HP CP4020, CP4520 User Manual

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COLOR LASERJET ENTERPRISE CP4020/CP4520

SERIES PRINTER

Service Manual

CP4025n CP4025dn CP4525n CP4525dn

CP4525xh

HP Color LaserJet Enterprise CP4020CP4520 Series Printers

Service Manual

Trademark Credits

, Acrobat®, and PostScript® are

Adobe trademarks of Adobe Systems Incorporated.

Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowed under the copyright laws.

The information contained herein is subject to change without notice.

The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

Part number: CC489-90936 Edition 1, 10/2009

Corel® is a trademark or registered trademark of Corel Corporation or Corel Corporation Limited.

Intel® Core™ is a trademark of Intel Corporation in the U.S. and other countries.

Java™ is a US trademark of Sun Microsystems, Inc.

Microsoft®, Windows®, Windows® XP, and Windows Vista® are U.S. registered trademarks of Microsoft Corporation.

PANTONE® is Pantone, Inc's checkstandard trademark for color.

is a registered trademark of The Open

UNIX Group.

ENERGY STAR and the ENERGY STAR mark are registered U.S. marks.

Conventions used in this guide

TIP: Tips provide helpful hi nts or sh or tcu t s. NOTE: Notes provide important information to explain a concept or to complete a task.

CAUTION: Cautions indicate procedures that you should follow to avoid losing data or damaging the

product.

WARNING! Warnings alert you to specific procedures that you should follow to avoid personal injury,

catastrophic loss of data, or extensive damage to the product.

ENWW iii

iv Conventions used in this guide ENWW

Table of contents

1 Theory of operation

Basic operation ...................... ...... ....... ..... ..................................... ....... ...... ..... ...................................... 2

Sequence of operation ......................................................................................................... 3

Engine-control system .............. .... ..... ..... .............................. ..... ..... .... ............................... ................... 4

DC controller ........................... .... ..... ..... ........................... ..... ..... .... ............................. ......... 5

Solenoids ............................................................................................................ 5

Clutches .............................................................................................................. 6

Switches .............................................................................................................. 6

Sensors ............................................................................................................... 7

Motors ................................................................................................................. 8

Fans ..................................................................................................................................... 9

High-voltage power supply ................ ..... ..... ....... ................................. ..... ....... ..... ............. 10

Low-voltage power supply ................................................................................................. 12

Overcurrent/overvoltage protection ................ ............ ....... ........... ........... .......... 13

Safety ................................................................................................................ 13

Voltage detection ............................................ ...... ...... ..... ................................ . 13

Sleep (powersave) mode ... ... ... ................ ................. ................ ................. ....... 13

Low-voltage power supply failure .............................. .... .... .... ...................... .... .. 13

Fuser control .................................... .......... ........ ........... ... .......... ......... .......... ......... ............ 14

Fuser temperature control ................................................................................. 15

Fuser sleeve temperature protection .............. ..... ..... ..... .............................. .... . 15

Failure detection ................... ..... ..... ..... ...... ................................ ..... ...... ...... ....... 16

Fuser unit identification ..................................................................................... 17

Fuser unit life detection ............. ... ... .... ... .................... ... .... ... .................... ... .... .. 17

Laser/scanner system .............. .... ... .... ... ..................... .... ... .... ...................... ... .... ... ............................ 18

Laser/scanner failure ......... ... .................... ... ... ... ................... .... ... ... .................... ... ... ... ...... 19

Protective-glass cleaners ................ .................................. ..... ....... ..... ................................ 19

Image-formation system ........... ..... ..... ............................. ..... ..... ..... ............................. ..... ......... ..... .... 21

Image-formation process ............ .... .... ...................... .... ... .... ...................... .... .... ... ............. 22

Step 1: Pre-exposure ............ ... .. .... .. ................. ... ... ... ................. ... ... ... ............. 24

Step 2: Primary charging ...................... ...... ..... ..... ............................... ..... ..... .... 24

Step 3: Laser-beam exposure .............. .... .... .... ... ........................ .... .... ... ........... 25

Step 4: Development ....................... .............................. ...... ...... ..... ................... 25

Step 5: Primary transfer ................ ................ ... ... ... ................. .. ... ... ................ .. 26

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Step 6: Secondary transfer ............................................................................... 26

Step 7: Separation ............................................................................................ 27

Step 8: Fusing ................................................................................................... 27

Step 9: ITB cleaning .......................................................................................... 28

Step 10: Drum cleaning ..................................................................................... 28

Print cartridge ............. ... .................. ... ... ... .................. ... ... ... .................. ... ... ... ................... 28

Developing-roller engagement and disengagement .......................................................... 30

Intermediate transfer belt (ITB) unit ................. ... .................... ... .... ... ..................... ... .... ... .. 31

Primary-transfer-roller enga gem ent and disengagement ....... ........................ ... 32

ITB cleaning ...................................................................................................... 34

Calibration .......................................................................................................................... 34

Color-misregistration control ............................................................................. 35

Image-stabilization control ................................................................................ 35

Pickup, feed, and delivery system ........................................... .... .... ...... ............................. .... ............ 37

Pickup-and-feed unit ................. ..... .... ..... ........................... ..... .... ..... ........................... ...... . 41

Cassette pickup ................................................................................................. 41

Cassette-presence detection ............................................................ 42

Cassette lift operation and cassette paper-presence detection ........ 43

Cassette multiple-feed prevent ion ..... ... .............. .............. ............... . 43

Multipurpose tray pickup ....................... ... ... ... ................ ... ... .. ................. ... .. ... .. 44

Paper feed ......................................................................................................... 45

Skew-feed prevention ....................................................................... 46

Paper detection ................................................................................ 47

Feed speed control .................. .... .... ..................... .... .... .... ................ 48

Fusing and delivery unit ....................... ........................... .... ..... ..... .......................... .... ...... . 48

Loop control ...................................................................................................... 49

Pressure-roller pressurization control .. .. .. .. ............ .. .. .. ............ .. .. .. ............ .. .. .. . 50

Duplexing unit (HP Color LaserJet CP4525dn, HP Color LaserJet CP4025dn, and HP

Color LaserJet CP4525xh only) ......................................................................................... 52

Duplexing reverse and feed control ......... .. ............ .. .. .. ............. .. .. .. ............. .. .. . 52

Duplex print operation ........... .... ... ... ... ..................... ... ... .... .................... ... .... ... .. 53

Jam detection ..................................................................................................................................... 55

Optional paper feeder ..................... ..... ...... ....... ..... ..................................... ....... ...... ....... .................... 57

Motor control ...................................................................................................................... 59

Paper-feeder pickup an d feed operati on ............... .............. .............. .............. .............. .... 60

Paper-size detection and cassette-presence d etectio n ..... ................. ................ ............... 62

Paper-feeder cassette lift operatio n ......... .... .... .... ..... ......................... ..... .... .... ................... 63

Paper feeder jam detection ................................................................................................ 64

2 Removal and replacement

Introduction ......................................................................................................................................... 68

Removal and replacement strategy ................................................................................................... 68

Electrostatic discharge .................. ....... ....... ....... ....... ....... ... ....... ........ ....... ....... ....... ... ....... ................. 69

Required tools ................................................................................................................................... 69

vi ENWW

Before performing service ............................................................................................................ .... .. 70

After performing service ............. ... ..................... .... ... .... ..................... .... ... .... ..................... ....... ......... 70

Post-service test ........................... ..... ..... .............................. ..... .... ..... ......................................... ..... .. 71

Print-quality test ............. .... ....................... .... .... ....................... .... .... .... ....................... .... ... 71

Parts removal order ............................................................................................................................ 72

Customer self repair (CSR) components .... ... .. ... .. ................ ... ... ... ................ ... .. ... ................ .. ... ... .. .. 74

Print cartridges ......................... ...... ...... .................................. ..... ....... ..... ........................... 74

Toner-collection unit ........................ .... .. ... ................. ... ... ... ................. .. .... .. .................. .. .. 76

Formatter PCA ................................................................................................................... 78

Hard drive ........................................ ... .... ... ..................... ... .... ... ..................... .... ... .... ......... 79

Remove the hard drive .................. ..... .... ... ..... ........................ .... ..... .... .............. 79

Memory DIMM ................................................................................................................... 81

Remove the memory DIMM .............................................................................. 81

Enable memory ........ .. ... .. .............. .. .. .. .............. .. .. .. .............. .. ... .. .... 82

Tray .................................... ...... ..... ....... ..... ................................... ..... ....... ..... ..................... 84

Fuser ....................................... ..... ....... ..... ....... .................................. ...... ..... ....... ............ .. 85

Feed and separation roller s (Tr ay s 2-5) .... .............. .............. ... .. ... ............. ... .. .. ............... . 86

Pickup roller (Tray 1) ................... .. .... .. ... ................. ... .. ... ................. ... ... ... ................. ... .. .. 87

Secondary transfer roller ....... .. .... .. ... ................. .. ... .. ................. ... .. ... ................. .. ... ... ....... 90

Reinstall the transfer roller ........ .. ... ... ... ................ ... .. ... ................ .. .... .. ............. 91

Intermediate transfer belt (ITB) .................. ........................... ... ...... ... ........................... .... .. 92

External panels, covers, and doors .................................................................................................... 95

Identification and location .................................................................................................. 95

Upper-left cover ..................... ... .... ... .................... ... .... ... .................... ... .... ... ...................... 96

Power-supply cover ................. ... ... .................... ... .... ... .................... ... ... ... .................... ... .. 98

Left cover ........................................................................................................................... 99

Remove the left cover .............. ... ... ... ................. .. ... ... ................. ... .. .... ............. 99

Front-top cover ................................... .... ....... ........ ....... ......... ....... .... ........ ....... ......... ....... 100

Remove the front-top cover ............................................................................. 100

Rear-top cover .................................................................. ...... ..... ....... ............................. 102

Remove the rear-top cover .............. ... ... ... .... ................... .. ... .... ................... ... 102

Right-front cover .................................... .......... ......... ..... ......... ......... ......... ......... .......... .... 103

Remove the right-front cover ...................... ..... ..... ............................... ..... ..... .. 103

Reinstall the power button .............................................................. 104

Control-panel assembly ................................................................................................... 105

Remove the control-panel assembly ........ ...................... ... .... ... ....................... 105

Front-door assembly ........................................................................................................ 107

Remove the front-door assembly .................................................................... 107

Right-rear cover .............................. ...... ..... ...... ...... .................................. ..... ....... ..... ....... 110

Remove the right-rear cover ............. ... ... ... ... ................... ... ... ... ................... ... 110

Rear cover .............................. .... ............................ ..... .... ..... ............................ .... ..... ...... 112

Remove the rear cover ............................................................. ..... ...... ..... ...... 112

Right-door assembly ........................................................................................................ 113

Internal assemblies .............. ......................... .... .... .... .......................... ... ..... .... ................................. 118

ENWW vii

Cassette feed guide ......................................................................................................... 118

Secondary transfer assembly .......................................................................................... 119

Reinstall the secondary transfer assembly ..................................................... 120

Separation pad (Tray 1) ................................................................................................... 121

Remove the separation pad (Tray 1) ...... .. .. ............ ............ ............ ............ .... 121

Registration density (RD) sensor assembly .............. ...... ................................. ..... ..... ..... . 124

Remove the RD sensor assembly ................................................................... 124

Registration assembly ......... ... ... ................ ... ... ... ................ ... ... ... ................ ... ... .. ............ 128

Remove the registration assembly .................................................................. 129

Residual-toner-feed motor ............................................................................................... 133

Remove the residual-toner-feed motor ........................................................... 133

Residual-toner duct and feed assembly .......................................................................... 134

Remove the residual-toner duct and feed assembly .... ... ... ................. ............ 134

Cartridge fan and environmental sensor ......................................... ................................ . 137

Remove the cartridge fan and environmental sensor ..................................... 137

Toner-collection sensor and scanner-thermistor assembly ............................................. 141

Remove the toner-collection sensor and scanner-thermistor assembly ......... 141

Delivery fan ............................ ..... ..... .... ............................. ..... .... .... ............................. ..... 143

Remove the delivery fan .......... ... .. .............. .. .. ... .............. .. ... .. .............. ... .. .. ... 143

Delivery assembly ........................... ...... .................................. ..... ....... ..... ........................ 145

Remove the delivery assembly ....................................................................... 145

Reinstall the delivery assembly ...................................................... 149

Duplex-drive assembly .................................................................................................... 151

Remove the duplex-drive assembly ....................... .... .. ... ................. ... ... ... ...... 151

Power-supply fan .................... ........................ ... .... .... ....................... .... .... ... .................... 152

Remove the power-supply fan ........................................................................ 152

Interconnect board (ICB) ................................................................................................. 153

Remove the ICB .............................................................................................. 153

DC controller PCA only ........................... ........................... .... ..... ..... .......................... ..... . 155

Remove the DC controller PCA only ............................................................... 155

Low-voltage power supply (LVPS) ................................................................................... 157

Remove the low-voltage power sup ply ........... .......... . . . . . .......... ......... .......... . . .. 157

DC controller PCA and tray ............................................................................................. 161

Remove the DC controller PCA and tray ........................................................ 161

High-voltage power supply lower (HVPS-D) ........ .... .... .... ....................... .... .... .... ............. 163

Remove the high-voltage power supply lower ................................................ 163

Reinstall the high-voltage power supply lower ............................... 167

Developing-disengagement motor ................................................................................... 168

Remove the developing-disengagement motor .............................................. 168

Exhaust fan and fan duct ................................................................................................. 169

Remove the exhaust fan and fan duct ............................................................ 169

Reinstall the exhaust fan and fan duct ............................................................ 171

Pickup motor .......................... ..... ...... .... .... ............................. .... ..... ..... ............................ 172

Remove the pickup motor ........... ... ... ... ................ .. ... ... ................ .. ... ... ........... 172

viii ENWW

Lifter-drive assembly .................................................... ..... ...... ..... .................................... 173

Remove the lifter-drive assembly .................... .. ... ... .............. .. ... .. ............... .. .. 173

Lifter base assembly ........................................................................................................ 175

Remove the lifter base assembly .................................................................... 175

Reinstall the lifter base assembly ....... ... ... ... ... ................. ... .... .. .................. ... .. 176

Tray-pickup drive assembly .......... ... .. ... .. ................ .. ... ... ................ .. ... .. ................ ... .. ... .. 178

Remove the tray-pickup drive assembly ......................................................... 178

Tray-pickup assembly ...................................................................................................... 180

Remove the tray-pickup assembly .................................................................. 180

Laser/scanner assembly (Y/M) ........................................................................................ 186

Remove the laser/scanner assembly (Y/M) .................................................... 187

Laser/scanner assembly (C/Bk) ....................................................................................... 190

Remove the laser/scanner assembly (C/Bk) ................................................... 191

Reinstall the protective glass cleaner (PGC) actuators ................ .. 193

High-voltage power supply upper (HVP S- T) ...................... ................... .................. ......... 196

Remove the high-voltage powe r suppl y up per ........... .. . . .......... .......... . . ......... .. 196

Reinstall the high-voltage power supply upper ............................... 198

Yellow, magenta, cyan, and black drum motors ... ............. ............ ............ ............ .......... 199

Remove the yellow, magenta, cyan, and black drum motors .......................... 199

Fuser motor .................... .................. ... ... ... .................. ... ... ... .................. ... ... ... ................ 200

Remove the fuser motor .................................................................................. 201

ITB motor ................... ... .. .... .................. ... ... ... .................. ... .... .. ................... .. .... ... ........... 202

Remove the ITB motor .................................................................................... 202

Main-drive assembly ........................................................................................................ 203

Remove the main-drive assembly ................................................................... 204

Reinstall the main-drive assembly .................................................. 207

Fuser-drive assembly ...................................................................................................... 211

Remove the fuser-drive assembly ................................................................... 212

Reinstall the fuser-drive assembly .................................................. 215

Optional paper feeder assemblies (1 x 500-sheet and 3 x 500-sheet) ............................................. 216

Front door (optional paper feeder) ......... ... ... .................. .. ... ... ................. ... .. .... ................ 216

Rear cover (optional paper feeder) ............ ... ................ .... .. ... ................. ... ... ... ................ 218

Right-front cover (optiona l pap er feeder) ......................................................................... 219

Right door (optional paper feeder) ...... ... .. .... .. .................. ... .. ... .................. .. .... .. .............. 22 0

Left cover (optional paper feeder) .................................................................................... 222

Remove the left cover (optional paper feeder) ................................................ 222

Right cover (optional paper feeder) ...... ... ... ... .. .................. .. .... .. ................. ... ... ... ............ 224

Remove the right cover (optional paper feeder) ....... ............. ............... ........... 224

Rear-right cover (optional paper feeder) .......................................................................... 225

Remove the rear-right cover (optional paper feeder) ...................................... 225

Pickup assembly (optional paper feeder) ........................................................................ 226

Remove the pickup assembly (optional paper feeder) .................................... 226

Lifter assembly (optional paper feeder) ......... ................. .. ... .. ................ .... .. ... ................ . 229

Remove the lifter assembly (optional paper feeder) ....................................... 229

ENWW ix

3 Solve problems

Solve problems checklist .................................................................................................................. 234

Menu map ........................................................................................................................................ 236

Troubleshooting process .................... ........ ........ .... ........ ........ ......... ........ ........ .... ........ ........ ............. 237

Tools for troubleshooting .................................................................................................................. 242

Lifter-drive assembly (op tio nal pape r fe ede r) ..... ............... ............... ............... ............... . 230

Remove the lifter-drive ass em bl y (opti onal paper feeder) .............................. 230

Pickup motor assembly (optional paper feeder) ............................................................. 231

Remove the pickup motor (optional paper feeder) assembly .......................... 231

Controller PCA (optional paper feeder) ....... .............. .. .. .. ............... .. .. .. ............... .. .. .. ...... 232

Remove the controller PCA (optional paper f e eder) ................ ....................... 232

Determine the problem source ........................................................................................ 237

Pre-troubleshooting checklist .......................................................................... 237

Troubleshooting flowchart ............................................................................... 239

Power subsystem ............................................................................................................ 240

Power-on checks ............................................................................................. 240

Power-on troubleshooting overview ............................................... 240

Individual component diagnos tics ...... ..... ......................... .......................... ...................... 242

LED diagnostics .............................................................................................. 242

Underst and lights on the fo rmatter .......... ....................................... 242

Engine diagnostics .......................................................................................... 243

Defeating interlocks ........................................................................ 243

Disable cartridge check ....... ... .. .............. .. ... .. ............. ... .. ... ............ 244

Engine-test button .......................................................................... 244

Paper-path test ................................................................................................ 245

Manual sensor test (special-mo de tes t) .... ............. ............. .............. ............. . 246

A TOP (top of page) sensor ............................................................ 247

B and C loop sensors ..................................................................... 248

D fuser delivery sensor ................. .... ... .... ... ..................... ... .... ... ..... 249

E duplex re-pickup sensor .............................................................. 250

F output bin full sensor ................................................................... 251

I developer alienation ...... .. ............. .. .. .. ............ ... .. .. ............ .. .. .. ..... 252

J fuser pressure-release sensor .......... ............... .. ... .. .............. ... .. . 253

K primary transfe r-r oll er -disengagement se nso r ............................ 254

L media sensor .............................................................................. 256

M front-door switch ......................................................................... 257

N right-door switch ................ ...... ..... .... .... ............................. ..... ..... 258

Manual sensor test 2 (special-mode test) ....................................................... 259

O Tray 1 paper present sensor ...................................................... 261

P Tray 2 paper present sensor ....................................................... 262

Q Tray 2 paper surface 1 and 2 sensors .................................. ...... 263

R Tray 2 paper size switches ........................................................ 264

x ENWW

S Tray 3 paper present sensor ....................................................... 265

T Tray 3 feed sensor ...................................................................... 265

U Tray 3 paper surface 1 and 2 s ensors ................. ....................... 265

V Tray 3 paper size switches .......................................................... 265

W Tray 4 paper present sensor ...................................................... 265

X Tray 4 feed sensor ...................................................................... 265

Y Tray 4 paper surface 1 and 2 sensors ........................................ 265

Z Tray 4 paper size switches .......................................................... 266

a Tray 5 paper present sensor .......... ............................................. 266

b Tray 5 feed sensor ....................................................................... 266

c Tray 5 paper surface 1 and 2 sensors ......................................... 266

d Tray 5 paper size switches .......................................................... 266

5V laser and 24V interlock and logic switches (and power

switch) ............................................................................................ 267

New ITB sensor .............................................................................. 271

Tray 3, 4, and 5 right door switch ........................................ ........... 272

Paper-path sensors test .................................................................................. 273

Print/stop test .................................................................................................. 273

Component tests ............................................................................................. 274

Component test (special-mode test) ................ ... .. .. ............. ... .. .. .... 274

Diagrams ......................................................................................................................... 277

Block diagrams ................................................................................................ 277

Plug/jack locations .......................................................................................... 280

Location of connectors .................................................................................... 281

DC controller connector locations ................................................... 281

Controller PCA (1 x 500-sheet and 3 x 500-sheet optional paper

feeders) ......................................................................................... 283

Locations of major components ...................................................................... 284

General timing chart ............ ... ... .. .................. .. ... ... ................. ... ... ... ................ 294

Circuit diagrams .............................................................................................. 294

HP Easy Printer Care ...................................................................................................... 298

Open the HP Easy Printer Care software ....... ................................................ 299

HP Easy Printer Care software sections ..... .................................................... 299

Internal print-quality test pages ........ ... ..................... .... .... ... ..................... .... .... ... ............. 302

Print-quality-troubleshooting pages ................................................................. 302

Diagnostics page ................................ ... .... ... ..................... .... ... .... ................... 305

Cleaning page ................................................................................................. 306

Configuration page ......... .................. ... ... ... ................. ... ... ... ................. ... ... ... .. 307

Configuration page ......................................................................... 307

HP embedded Jetdirect page ......................................................... 309

Embedded protocol page ............................................................... 310

Finding important information on the configuration pages .............. 311

Color-band test ................................................................................................ 311

Print-quality troubleshooti ng to ols ....................... ..................... ..................... ................... 312

ENWW xi

Repetitive defects ruler ........ ... .. ............... .. .. ... .............. ... .. .. ............... .. .. ... ..... 312

Calibrate the product ................. .... .... ......................... .... .... .... ......................... 313

Control panel menus ........................................................................................................ 314

Control panel menus .................. ................................ ..... ..... ..... ...................... 314

Show Me How menu ...................................................................... 314

Retrieve job menu .......................................................................... 314

Information menu ............................................................................ 317

Paper handling menu ..................................................................... 317

Manage supplies menu ....... ... ... ... ................ ... .. .... ................ ... ... ... 318

Configure device menu ........... .... ..... ..... ........................... ............... 321

Diagnostics menu ........................................................................... 342

Service menu .................................................................................. 344

Interpret control-panel messages .................................................................................... 345

Control-panel message types ........ ................... ... .. .... .................. ... ... ... .......... 345

Control-panel messages ................................................................................. 345

Event log messages ........................................................................................................ 376

Print an event log ............................................................................................ 376

Show an event log .......................................................... ...... ...... ..... ................ 376

Sample event log ................. ... .... ... ..................... ... ... .... .................... .... ... .... ... 377

Clear the event log .......................................................................................... 377

Event log message table ................................................................................. 378

Clear paper jams ........................................................... ..... ....... ....... ................................................ 383

Common causes of jams ................................................................................................. 383

Jam locations ...................... .... .... ..... ............................ ..... ..... ..... ........................... ..... ..... 386

Clear jams in the right door .............................................................................................. 387

Clear jams in the output bin area ..................................................................................... 390

Clear jams in Tray 1 ......................................................................................................... 390

Clear jams in Tray 2 or optional Trays 3, 4, or 5 .................................. ..... ....................... 392

Clear jams in the lower right door (Tray 3, 4, or 5) .......................................................... 393

Jam causes and solutions ............................................................................................... 394

Jams in the output bin ..................................................................................... 394

Jams in the fuser and transfer area ................................................................ 394

Jams in the duplex area (HP Color LaserJet CP4525dn, HP Color LaserJet

CP4025dn, and HP Color LaserJet CP4525xh only) ...................................... 397

Jams in Tray 1, Tray 2 and internal paper path .............................................. 399

Jams in Tray 3, 4, and 5 .................................................................................. 400

Change jam recovery ............................ ..... .................................. ...... ...... ..... ................... 402

Solve paper-handling problems ........... ....... ..................................... ...... ..... ...................................... 403

Product feeds multiple sheets .......................................................................................... 403

Product feeds incorrect page size ............... ... .... ... .... .................... ... .... ... ..................... ... 403

Product pulls from incorrect tray .................... ...... ..... ...... ..... .................................. ..... ..... 403

Paper does not feed automatically .................................................................................. 404

Paper does not feed from Tray 2, 3, 4, or 5 ..................................................................... 404

Transparencies or glossy paper will not feed ........... ... .................. ... ... ... .................. .... ... 405

xii ENWW

Envelopes jam or will not feed in the product .................................................................. 405

Output is curled or wrinkled ................... ... ... .................. ... .... .. ................... ... ... ... ............. 406

Product will not duplex or duplexes incorrect ly ........................... ....................... .............. 406

Use manual print modes .................................................................................................................. 408

Solve image-quality problems ....... ... .... ... ..................... ... ... .... .................... .... ... ... ............................ 410

Image defects table ............. ................. ... ... ... ................. ... .. .... ................ .... .. ... ............... 410

Clean the product ............................................................................................................................. 416

Clean the paper path ....................................................................................................... 416

Solve performance problems ........................................................................................................... 417

Solve connectivity problems ............................................................................................................. 418

Solve direct-connect problems ....... ................ .. ... ... ............... .. ... .. ................ .. ... ... ........... 418

Solve network problems ............. ... ................ .. .... .. ................ ... ... ... ................ .. .... .. ......... 418

Service mode functions .................................................................................................................... 420

Service menu ..................... ..... .... .... ...... ........................... ..... ..... .... ............................. ..... 420

Product resets .................................................................................................................. 423

Restore factory-set defaults ....... ... .. ... ............... ... .. .... ............... ... .. ... .............. 423

Hard disk initialization (optional ) .... .. ... .. ............ .. ... .. ............ .. ... .. ............ .. ... .. . 423

NVRAM initialization ........................................................................................ 423

Product cold reset .......................................................................................... 424

Product updates ............ .... .... .... ... ...................... .... .... .... ..................... .... .... .... ................................. 424

4 Parts and diagrams

Order parts, accessories, and supplies ......... .... ...................... .... .... ... ....................... .... ... .... ............ 426

Part numbers ......................... ..... ..... ............................... ..... ..... ..... .............................. ..................... 427

Accessories ..................................................................................................................... 427

Print cartridges and toner collection unit .......................................................................... 427

Memory ............................................................................................................................ 427

Cables and interfaces ...................................................................................................... 427

Customer self repair (CSR) parts .................................................................................... 428

Service maintenance kits ................ .......................... ..... ..... .... ........................... .... ..... .... . 428

Unique components ......................................................................................................... 429

Screws .............................................................................................................................................. 430

How to use the parts lists and diagrams .......................................................................................... 431

External covers, panels, and doors .................................................................................................. 432

Right door assembly ......................................................................................................................... 434

Front door assembly ......................................................................................................................... 436

Internal components ................ ..... ..... ..... .............................. .... ..... ..... ............................... ............... 438

Internal components (1 of 7) ............................................................................................ 438

Internal components (2 of 7) ............................................................................................ 440

Internal components (3 of 7) ............................................................................................ 442

Internal components (4 of 7) ............................................................................................ 444

Internal components (5 of 7) ............................................................................................ 446

Internal components (6 of 7) ............................................................................................ 448

ENWW xiii

Internal components (7 of 7) ........................................... ... ..... .... ........................... .... ..... . 450

Cassettes 2-5 ............................ ..... ....... ..... ....... .................................. ...... ..... ....... ........... 452

Paper pickup assembly .................................................................................................... 454

Tray 1 paper pickup assembly ......................................................................................... 456

Registration assembly ......... ... ... ................ ... ... ... ................ ... ... ... ................ ... ... .. ............ 458

Secondary transfer assembly .......................................................................................... 460

Delivery assembly ........................... ...... .................................. ..... ....... ..... ........................ 462

Fuser assembly ................................ ... ... ... ................. ... ... ... .................. .. ... ... ................. . 464

PCAs ................................................................................................................................ 466

Assessories ....................... ......................... .... ..... .... ......................... ..... .... ..... .................................. 468

Paper feeders .................. ... .... ... .... .................... ... .... ... ..................... ... ... .... ..................... 468

Paper feeder external covers, panels, and doors ............ .... ................. ... ... ... ................. . 470

1 X 500 paper feeder main body ..................................................................................... 472

3 X 500 paper feeder main body ..................................................................................... 474

Alphabetical parts list ....................................................................................................................... 476

Numerical parts list ........................................................................................................................... 484

Appendix A Service and support

Hewlett-Packard limited warranty statement .... .... ...................... .... ... .... ..................... .... ... .... ........... 494

HP's Premium Protection Warranty: LaserJet print cartridge limited warranty statement ................ 495

HP Color LaserJet Fuser Kit Limited Warranty Statement ............................................................... 496

End User License Agreement ............................. ... ... ... ................. ... .... .. .................. ... ... ... ............... 497

Customer self-repair warranty service ........... ..... ...... .................................... ...... ..... ....... .................. 499

Customer support ................... ..... ..... ..... .............................. ..... ..... ..... .............................. ................ 500

Appendix B Product specifications

Physical specifications .............. ....... ...... ... ...... ....... ..... ....... ...... ... ...... ....... ..... ....... ...... ... ................... 502

Performance specifications ....... .................... .... ... ... ..................... ... .... .... .................... .... ... ... ........... 502

Electrical specifications ...... ... .... .... ..................... ... .... ... ..................... .... ... .... .................................... 502

Acoustic specifications ....... .... ... .... ..................... ... .... ... ...................... ... .... ... ..................... ............... 503

Environmental specifications ........... .......... ......... .......... .......... ......... ..... .......... ......... .......... ............... 503

Skew specifications .............. ........................ ..... .... ... .......................... .... ..... ... .................................. 504

Appendix C Regulatory information

FCC regulations ............................................................................................................................... 506

Environmental product stewardship pro gram ..... ..... .... ..... .... ........................... ..... ..... ... .................... 507

Protecting the environment ............. .... ........................... .... ..... .... ........................... .... ..... . 507

Ozone production ............................................................................................................ 507

Power consumption ......................................................................................................... 507

Toner consumption .......................................................................................................... 507

Paper use ........................................................................................................................ 507

Plastics ............................................................................................................................ 507

HP LaserJet print supplies ............................................................................................... 507

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Return and recycling instructions ..................................................................................... 508

United States and Puerto Rico ........................................................................ 508

Multiple returns (more than one cartridge) ....................... ... .. ... ...... 508

Single returns ................................................................................. 508

Shipping .......................................................................................... 508

Non-U.S. returns ............................................................................................. 508

Paper ............................................................................................................................... 508

Material restrictions .................. ....... ..... .................................. ...... ...... ..... ......................... 509

Disposal of waste equipment by users in private households in the European

Union ........................ ..... ..... ..... ..... ............................ ..... ..... ..... ............................ ..... ....... 509

Chemical substances ....................................................................................................... 509

Material Safety Data Sheet (MSDS) ................................................................................ 510

For more information ....................................................................................................... 510

Declaration of Conformity .............. ..... ..... ...... ..... ............................. ..... ..... .... ................................... 511

Safety statements .......................... ...... ..................................... ..... ....... ....... ..................................... 512

Laser safety .................................. .................................. ...... ..... ....... ............................... 512

Canadian DOC regulations ............. .... ..... ... ..... .......................... ..... ..... .... ........................ 512

VCCI statement (Japan) .................................................................................................. 512

Power cord instructions ................................................................................................... 512

Power cord statement (Japan) ......................................................................................... 512

EMC statement (China) ................................................................................................... 513

EMC statement (Korea) ................................................................................................... 513

EMI statement (Taiwan) ................................................................................................... 513

Laser statement for Finland ............................................................................................. 513

GS statement (Germany) .................................. ..... ..... ....... ..... .................................. ....... 514

Substances Table (China) ................... ...... ...... ................................. ..... ....... ..... .............. 514

Restriction on Hazardous Substances statem ent (Turkey) ....................... .................... .. 514

Index ................................................................................................................................................................. 515

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xvi ENWW

List of tables

Table 1-1 Sequence of operation ........... .... ..... .... ........................... ... ..... .... .......................... ..... . ........................ 3

Table 1-2 Solenoids .............. .... ... ... ..................... ... .... ... ..................... .... ... .... .................................................... 5

Table 1-3 Switches ......................... ..... ..... ..... ................................. ..... ..... ..... ..................................................... 6

Table 1-4 Sensors ......................... ..... ........................... .... ..... ..... ... ............................ ..... ................................... 7

Table 1-5 Motors ...................... .... .... .... ........................ ... .... ..... ....................... .... .... .... ....................................... 8

Table 1-6 Fans ........................ .... .... .... ........................ .... .... .... ........................ .... .... .... ....................................... 9

Table 1-7 High-voltage power supply circuits ........................ ...................................... ....... ...... ....... ....... ...... .... 10

Table 1-8 Converted DC voltages ................ .... .... ..... .... .......................... ... ..... .... .......................... .... .... ..... .... .. 12

Table 1-9 Fuser components ................................ .... ... .... ................... ... ... ... .................... ... .... ...... ................... 14

Table 1-10 Primary-transfer-rolle r eng agem ent s tates ... ...... ....... ....... ........................................ ...................... 32

Table 1-11 Image-stabilization cont rols ............ ....... ....... ...... ....................................... ...... ....... ....... ...... ........... 36

Table 1-12 Switches and sensors for the pickup, feed, and de li very system ...... .......................... ................... 38

Table 1-13 Motors and solenoid s for the pic kup, feed, and delivery system .. .. . . . . . . ........ .. . . . . . . . . ........ .. . . . . . . . . ..... 39

Table 1-14 Print mode and feed speed ................. ......................... .... ..... ... .......................... .... ..... . .. ..... .... .... ... 48

Table 1-15 Paper sizes .................. .... ... .... .................... ... ... .... ..................... ... ... ... ......................... ... ... ... .... ..... 53

Table 1-16 Jams that the product detects ........................................................................................................ 56

Table 1-17 Electrical components for the paper feeder ............................................................................ ... .. .. 59

Table 1-18 Pickup feed components (1 x 500-sheet paper feede r) ..... ................ ................. ................. .......... 60

Table 3-1 Pre-troubleshooting checkli st ........ ......................... .... .... ..... ........................ .... ..... ... ....................... 237

Table 3-2 Troubleshooting flowchart ........... .......................... .... ..... ... .......................... .... .... .... .... ................... 239

Table 3-3 Manual sensor diagnostic tests ....................................... ..... ..... ..... ............................... ................. 246

Table 3-4 Default state of bits .................. .................... .... ... ... ................... ... .... ... ........................................... 246

Table 3-5 Manual sensor test 2 diagnostic tests .................................... .... .... .... ....................... ..... ... ............. 259

Table 3-6 Default state of bits .................. .................... .... ... ... ................... ... .... ... ........................................... 260

Table 3-7 Paper-path sensors diagnostic tests .......... .... ........................ .... ... .... ........................ .... ................. 273

Table 3-8 Component test details .................................................................................................................. 274

Table 3-9 Formatter PCA ......................... ...................... .... .... .... ...................... .... ... .... ................................... 280

Table 3-10 DC controller connectors ............................................................... ....... ....... ...... ........................... 281

Table 3-11 Controller PCA connectors .................... ....................................... ...... ....... ....... ............................ 283

Table 3-12 Important information on the configuration pag es ......... ............................. ........................... .. ..... 311

Table 3-13 Embedded Jetdirect menu ........ ... .... ..................... ... .... ... ...................... ... .... ... ............................. 334

Table 3-14 Control-panel messages ...... .... ... .... ..................... ... .... ... ...................... ... .... ... .............................. 345

Table 3-15 Common causes of jams (by area) .............................................................................................. 385

Table 3-16 Causes and solutions for delivery delay jam ................................................................................ 394

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Table 3-17 Causes and solutions for fuser delivery delay jams ..................................................................... 394

Table 3-18 Causes and solutions for wrapping jams ..................................................................................... 394

Table 3-19 Causes and solutions for fuser delivery stationary jams .............................................................. 395

Table 3-20 Causes and solutions for residual media jams ............................................................................ 396

Table 3-21 Causes and solutions for pickup delay jams 2 ............................................................................. 396

Table 3-22 Causes and solutions for pickup stationary jams ......................................................................... 397

Table 3-23 Causes and solutions for duplexing reverse jams ..... ............ ............. ............ ............. ............... 397

Table 3-24 Causes and solutions for duplex repick jams .............................................................................. 397

Table 3-25 Causes and solutions for residual media jams ............................................................................ 398

Table 3-26 Causes and solutions for pickup delay jam 1: tray pickup ........................................................... 399

Table 3-27 Causes and solutions for pickup stationary jams ......................................................................... 400

Table 3-28 Causes and solutions for pickup delay and pickup stationary jams ............................................. 400

Table 3-29 Causes and solutions for residual media jams ............................................................................ 401

Table 3-30 MP modes under the ADJUST PAPER TYPES sub menu ......................................................... 408

Table 3-31 MP modes under the OPTIMIZE submenu .................................................................................. 409

Table 4-1 Maintenance kits ............................................................................................................................ 428

Table 4-2 110V and 220V unique components .............................................................................................. 429

Table 4-3 Simplex and duplex unique components .... ... ................. ................ ................. ................ .............. 429

Table 4-4 Common fasteners ........................................................................................................................ 430

Table 4-5 External covers, panels, and doors; .............................................................................................. 433

Table 4-6 Right door assembly ...................................................................................................................... 435

Table 4-7 Front door assembly ...................................................................................................................... 437

Table 4-8 Internal components (1 of 7) .......................................................................................................... 439

Table 4-9 Internal components (2 of 7) .......................................................................................................... 441

Table 4-10 Internal components (3 of 7) ................. ... .... ... ..................... .... ... .... .................... .... ... .................. 443

Table 4-11 Internal components (4 of 7) ................. ... .... ... ..................... .... ... .... .................... .... ... .................. 445

Table 4-12 Internal components (5 of 7) ................. ... .... ... ..................... .... ... .... .................... .... ... .................. 447

Table 4-13 Internal components 6 of 7 .......................................................................................................... 449

Table 4-14 Internal components 7 of 7 .......................................................................................................... 451

Table 4-15 Cassette ....................................................................................................................................... 453

Table 4-16 Paper pickup assembly ................................................................................................................ 455

Table 4-17 Tray 1 paper pickup assembly ..................................................................................................... 457

Table 4-18 Registration assembly .................................................................................................................. 459

Table 4-19 Secondary Transfer assembly ......... ... ... ... ... .................. ... .. .... ................. ... ... ... ........................... 461

Table 4-20 Delivery assembly ........................................................................................................................ 463

Table 4-21 Fuser assembly ............................................................................................................................ 465

Table 4-22 PCAs ............................................................................................................................................ 467

Table 4-23 Paper feeders ............................................................................................................................... 469

Table 4-24 Paper feeder external covers, panels, and doors ........................................................................ 471

Table 4-25 1 X 500 paper feeder main body .................................................................................................. 473

Table 4-26 3 X 500 paper feeder main body .................................................................................................. 475

Table 4-27 Alphabetical parts list ......... .... ... ...................... .... .... ... ...................... .... ... .... ................................. 476

Table 4-28 Numerical parts list ....................................................................................................................... 484

Table B-1 Product dimensions ....................................................................................................................... 502

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Table B-2 Product dimensions, with all doors an d trays full y op ened ....... ... .................... ................... ........... 502

Table B-3 Power requirements ........................... ...................................... ....... ....... ...... .................................. 503

Table B-4 Power consumpt io n (a ver age, in watts) Table B-5 HP Color LaserJet Ente rpr i se CP 402 0- CP4 520 Ser ies

1246

.............................. .... ..... ............................. ..... ...... .... . 503

.............................................................. 503

Table B-6 Media registration and im age pl ac eme nt ac cu rac y ................. ............... .............. ............... .......... 504

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List of figures

Figure 1-1 Relationship between the main product systems ............................................................................. 2

Figure 1-2 Engine-control system ...................................................................................................................... 4

Figure 1-3 DC controller block diagram .............................................................................................................. 5

Figure 1-4 High-voltage power supply circuits ............................................................................................. .. .. 10

Figure 1-5 Low-voltage power-supply circuit ....................... ............................. ..... ..... ..... ................................. 12

Figure 1-6 Fuser components ................................................................................................................. ... .... .. 14

Figure 1-7 Fuser temperature-control circuit ............. .... ........................ .... .... .... ........................ .... ........ .... .... ... 15

Figure 1-8 Laser/scanner system ..................................................................................................................... 18

Figure 1-9 Protective-glass cleaners (PGCs) .................. ............................. ...... ..... ..... .... ................................ 20

Figure 1-10 Image-formation system ....... ... .................. .... .. ... ................... ... ... .... .................. ... ... ... ... .... .. ......... 21

Figure 1-11 Image-formation drive system .............................................................................................. ....... .. 22

Figure 1-12 Image-formation process .............................................................................................................. 23

Figure 1-13 Pre-exposure ................................................................................................................................ 24

Figure 1-14 Primary charging ......................................................................................................................... .. 24

Figure 1-15 Laser-beam exposure ................................................................................................................... 25

Figure 1-16 Development .......................................................................................................................... ..... .. 25

Figure 1-17 Primary transfer ................................................................................................................... ... .... .. 26

Figure 1-18 Secondary transfer ........................................................................................................................ 26

Figure 1-19 Separation ................................................................................................................................... .. 27

Figure 1-20 Fusing ............................................................................................................................ ............... 27

Figure 1-21 ITB cleaning .................................................................................................................................. 28

Figure 1-22 Drum cleaning ............................................................................................................................. .. 28

Figure 1-23 Print-cartridge system ................................................................................................ ................... 29

Figure 1-24 Developing-rolle r en gagement and disengageme nt co ntrol ............. ............. ............ ............. ...... 30

Figure 1-25 ITB unit ................................................................................................................................. ....... .. 31

Figure 1-26 Three states of primary-transfer-roller engagement and disengagement ..................................... 33

Figure 1-27 ITB cleaning process ............................................................................................................ ... ... .. 34

Figure 1-28 Toner patterns for calibration ........... .... .... .... ......................... .... .... ......................... ....................... 35

Figure 1-29 Paper path .............................................................................................................................. .... .. 37

Figure 1- 30 Switches and sensors for the pickup, feed, and delivery system ....... .......................................... 38

Figure 1- 31 Motors and solenoids for the pickup, feed, and delivery system .................................................. 39

Figure 1-32 Three main units of the pickup, feed, and delivery system ........................................................... 40

Figure 1-33 Pickup-and-feed unit ..................................................................................................................... 41

Figure 1-34 Cassette-pickup mechanism ......................................................................................................... 42

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Figure 1-35 Cassette lift mechanism ................................................................................................................ 43

Figure 1-36 Multiple-feed prevention ................................................................................................................ 44

Figure 1-37 Multipurpose tray pickup mechanism ........... ...... ....... ....... ........................................ ...... ............... 45

Figure 1-38 Paper-feed mechanism ................................................................................................................. 46

Figure 1-39 Skew-feed prevention ............ .... ... ..................... .... .... .... ..................... .... ... .... ............................... 47

Figure 1-40 Fuser and delivery unit .................................................................................................................. 49

Figure 1-41 Loop-control mechanism ............................................................................................................... 50

Figure 1-42 Pressure-roller pressurization control ..... ... ... .... ................... ... ... ... .................... ... .... ... ... ............... 51

Figure 1-43 Duplexing unit ............................................................................................................................... 52

Figure 1-44 Duplex reverse and feed control ................................................................................................... 53

Figure 1-45 Jam detection sensors .................................................................................................................. 55

Figure 1-46 1 x 500 optional paper feeder ....................................................................................................... 57

Figure 1-47 3 x 500-sheet optional paper feeder ............................................................................................. 58

Figure 1-48 Signals for the paper feeder .......... ... .. ................ ... .. ... ................ ... .. .... ............... ... ... .................... 58

Figure 1-49 Paper-feeder pickup and feed op er atio n .... .............. .............. ............... .............. .............. ........... 60

Figure 1-50 Paper-feeder cassette lift ............................................................................................................. 63

Figure 1-51 Jam detection (1 x 500-sheet paper feeder) ................................................................................. 64

Figure 1-52 Jam detection (3 x 500-sheet paper feeder) ................................................................................. 65

Figure 2-1 Phillips and pozidrive screwdriver comparison ...... .. .................. ... .... ... .................. .. .... ... ................ 69

Figure 2-2 Parts removal order (1 of 2) ............................................................................................................ 72

Figure 2-3 Parts removal order (2 of 2) ............................................................................................................ 73

Figure 2-4 Remove the print cartridge (1 of 2) ................................................................................................. 74

Figure 2-5 Remove the print cartridge (2 of 2) ................................................................................................. 75

Figure 2-6 Remove the toner-collection unit (1 of 4) ........................................................................................ 76

Figure 2-7 Remove the toner-collection unit (2 of 4) ........................................................................................ 76

Figure 2-8 Remove the toner-collection unit (3 of 4) ........................................................................................ 77

Figure 2-9 Remove the toner-collection unit (4 of 4) ........................................................................................ 77

Figure 2-10 Remove the formatter ................................................................................................................... 78

Figure 2-11 Remove the hard drive (1 of 3) ..................................................................................................... 79

Figure 2-12 Remove the hard drive (2 of 3) ..................................................................................................... 79

Figure 2-13 Remove the hard drive (3 of 3) ..................................................................................................... 80

Figure 2-14 Remove the memory DIMM (1 of 2) .............................................................................................. 81

Figure 2-15 Remove the memory DIMM (2 of 2) .............................................................................................. 82

Figure 2-16 Remove the tray (1 of 2) ............................................................................................................... 84

Figure 2-17 Remove the tray (2 of 2) ............................................................................................................... 84

Figure 2-18 Remove the fuser (1 of 2) ............................................................................................................. 85

Figure 2-19 Remove the fuser (2 of 2) ............................................................................................................. 85

Figure 2-20 Remove the Pickup and feed rollers (Trays 2-5) .......................................................................... 86

Figure 2-21 Remove the pickup roller (Tray 1) (1 of 5) .................................................................................... 87

Figure 2-22 Remove the pickup roller (Tray 1) (2 of 5) .................................................................................... 87

Figure 2-23 Remove the pickup roller (Tray 1) (3 of 5) .................................................................................... 88

Figure 2-24 Remove the pickup roller (Tray 1) (4 of 5) .................................................................................... 88

Figure 2-25 Remove the pickup roller (Tray 1) (5 of 5) .................................................................................... 89

Figure 2-26 Remove the transfer roller (1 of 3) ................................................................................................ 90

xxii ENWW

Figure 2-27 Remove the transfer roller (2 of 3) ................................................................................................ 90

Figure 2-28 Remove the transfer roller (3 of 3) ................................................................................................ 91

Figure 2-29 Reinstall the transfer roller ......................................................................................... .... .... ........... 91

Figure 2-30 Remove the intermediate transfer belt (1 of 4) ......................................................................... .. .. 92

Figure 2-31 Remove the intermediate transfer belt (2 of 4) ......................................................................... .. .. 92

Figure 2-32 Remove the intermediate transfer belt (3 of 4) ......................................................................... .. .. 93

Figure 2-33 Remove the intermediate transfer belt (4 of 4) ......................................................................... .. .. 94

Figure 2-34 External panels, covers, and doors; identification and location .................................................... 95

Figure 2-35 Remove the upper-left cover (1 of 3) ....................................................................................... ... .. 96

Figure 2-36 Remove the upper-left cover (2 of 3) ....................................................................................... ... .. 96

Figure 2-37 Remove the upper-left cover (3 of 3) ....................................................................................... ... .. 97

Figure 2-38 Remove the power-supply cover .................................................................................................. 98

Figure 2-39 Remove the left cover (1 of 2) ....................................................................................................... 99

Figure 2-40 Remove the left cover (2 of 2) ....................................................................................................... 99

Figure 2-41 Remove the front-top cover (1 of 3) ............................................................................................ 100

Figure 2-42 Remove the front-top cover (2 of 3) ............................................................................................ 100

Figure 2-43 Remove the front-top cover (3 of 3) ............................................................................................ 101

Figure 2-44 Remove the rear-top cover (1 of 2) ............................................................................................. 102

Figure 2-45 Remove the rear-top cover (2 of 2) ............................................................................................. 102

Figure 2-46 Remove the right-front cover (1 of 3) .......................................................................................... 103

Figure 2-47 Remove the right-front cover (2 of 3) .......................................................................................... 103

Figure 2-48 Remove the right-front cover (3 of 3) .......................................................................................... 104

Figure 2-49 Reinstall the power button .......................................................................................................... 104

Figure 2-50 Remove the control-panel assembly (1 of 2) .............................................................................. 105

Figure 2-51 Remove the control-panel assembly (2 of 2) .............................................................................. 106

Figure 2-52 Remove the front-door assembly (1 of 5) ................................................................................... 107

Figure 2-53 Remove the front-door assembly (2 of 5) ................................................................................... 108

Figure 2-54 Remove the front-door assembly (3 of 5) ................................................................................... 108

Figure 2-55 Remove the front-door assembly (4 of 5) ................................................................................... 109

Figure 2-56 Remove the front-door assembly (5 of 5) ................................................................................... 109

Figure 2-57 Remove the right-rear cover (1 of 2) ........................................................................................... 110

Figure 2-58 Remove the right-rear cover (2 of 2) ........................................................................................... 111

Figure 2-59 Remove the rear cover ............................................................................................................... 112

Figure 2-60 Remove the right-door assembly (1 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 113

Figure 2-61 Remove the right-door assembly (2 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 113

Figure 2-62 Remove the right-door assembly (3 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 114

Figure 2-63 Remove the right-door assembly (4 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 114

Figure 2-64 Remove the right-door assembly (5 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 115

Figure 2-65 Remove the right-door assembly (6 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 115

Figure 2-66 Remove the right-door assembly (7 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 116

Figure 2-67 Remove the right-door assembly (8 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 116

Figure 2-68 Remove the right-door assembly (9 of 9) ........... .. .. ... .. .............. .. ... .. .............. .. .. ... ..................... 117

Figure 2-69 Remove the cassette feed guide (1 of 2) .................................................................................... 118

Figure 2-70 Remove the cassette feed (2 of 2) .............................................................................................. 118

ENWW xxiii

Figure 2-71 Remove the secondary transfer assembly (1 of 3) ..................................................................... 119

Figure 2-72 Remove the secondary transfer assembly (2 of 3) ..................................................................... 119

Figure 2-73 Remove the secondary transfer assembly (3 of 3) ..................................................................... 120

Figure 2-74 Reinstall the secondary transfer assembly ...... .... .. ................... ... ... ... .................. .... .. ... .............. 120

Figure 2-75 Remove the separation pad (1 of 6) ........................................................................................... 121

Figure 2-76 Remove the separation pad (2 of 6) ........................................................................................... 121

Figure 2-77 Remove the separation pad (3 of 6) ........................................................................................... 122

Figure 2-78 Remove the separation pad (4 of 6) ........................................................................................... 122

Figure 2-79 Remove the separation pad (5 of 6) ........................................................................................... 123

Figure 2-80 Remove the separation pad (6 of 6) ........................................................................................... 123

Figure 2-81 Remove the RD sensor assembly (1 of 7) .................................................................................. 124

Figure 2-82 Remove the RD sensor assembly (2 of 7) .................................................................................. 124

Figure 2-83 Remove the RD sensor assembly (3 of 7) .................................................................................. 125

Figure 2-84 Remove the RD sensor assembly (4 of 7) .................................................................................. 125

Figure 2-85 Remove the RD sensor assembly (5 of 7) .................................................................................. 126

Figure 2-86 Remove the RD sensor assembly (6 of 7) .................................................................................. 126

Figure 2-87 Remove the RD sensor assembly (7 of 7) .................................................................................. 127

Figure 2-88 Remove the registration assembly (1 of 8) ................................................................................. 129

Figure 2-89 Remove the registration assembly (2 of 8) ................................................................................. 129

Figure 2-90 Remove the registration assembly (3 of 8) ................................................................................. 130

Figure 2-91 Remove the registration assembly (4 of 8) ................................................................................. 130

Figure 2-92 Remove the registration assembly (5 of 8) ................................................................................. 131

Figure 2-93 Remove the registration assembly (6 of 8) ................................................................................. 131

Figure 2-94 Remove the registration assembly (7 of 8) ................................................................................. 132

Figure 2-95 Remove the registration assembly (8 of 8) ................................................................................. 132

Figure 2-96 Remove the residual-toner-feed motor ....................................................................................... 133

Figure 2-97 Remove the residual-toner duct and feed assembly (1 of 4) ...................................................... 134

Figure 2-98 Remove the residual-toner duct and feed assembly (2 of 4) ...................................................... 135

Figure 2-99 Remove the residual-toner duct and feed assembly (3 of 4) ...................................................... 135

Figure 2-100 Remove residual-toner duct and feed assembly (4 of 4) .......................................................... 136

Figure 2-101 Remove the cartridge fan and environmental sensor (1 of 7) ................................................... 137

Figure 2-102 Remove the cartridge fan and environmental sensor (2 of 7) ................................................... 138

Figure 2-103 Remove the cartridge fan and environmental sensor (3 of 7) ................................................... 138

Figure 2-104 Remove the cartridge fan and environmental sensor (4 of 7) ................................................... 139

Figure 2-105 Remove the cartridge fan and environmental sensor (5 of 7) ................................................... 139

Figure 2-106 Remove the cartridge fan and environmental sensor (6 of 7) ................................................... 140

Figure 2-107 Remove the cartridge fan and environmental sensor (7 of 7) ................................................... 140

Figure 2-108 Remove the toner-collection sensor and scanner-thermistor assembly (1 of 3) ....................... 141

Figure 2-109 Remove the toner-collection sensor and scanner-thermistor assembly (2 of 3) ....................... 142

Figure 2-110 Remove the toner-collection sensor and scanner-thermistor assembly (3 of 3) ....................... 142

Figure 2-111 Remove the delivery fan (1 of 2) ............................................................................................... 143

Figure 2-112 Remove the delivery fan (2 of 2) ............................................................................................... 144

Figure 2-113 Remove the delivery assembly (1 of 7) .................................................................................... 145

Figure 2-114 Remove the delivery assembly (2 of 7) .................................................................................... 146

xxiv ENWW

Figure 2-115 Remove the delivery assembly (3 of 7) .................................................................................... 146

Figure 2-116 Remove the delivery assembly (4 of 7) .................................................................................... 147

Figure 2-117 Remove the delivery assembly (5 of 7) .................................................................................... 147

Figure 2-118 Remove the delivery assembly (6 of 7) .................................................................................... 148

Figure 2-119 Remove the delivery assembly (7 of 7) .................................................................................... 148

Figure 2-120 Reinstall the delivery assembly (1 of 4) .................................................................................... 149

Figure 2-121 Reinstall the delivery assembly (2 of 4) .................................................................................... 149

Figure 2-122 Reinstall the delivery assembly (3 of 4) .................................................................................... 150

Figure 2-123 Reinstall the delivery assembly (4 of 4) .................................................................................... 150

Figure 2-124 Remove the duplex-drive assembly ......................................................................................... 151

Figure 2-125 Remove the power-supply fan .................................................................................................. 152

Figure 2-126 Remove the ICB (1 of 2) ........................................................................................................... 153

Figure 2-127 Remove the ICB (2 of 2) ........................................................................................................... 154

Figure 2-128 Remove the DC controller PCA only (1 of 2) ............................................................................ 155

Figure 2-129 Remove the DC controller PCA only (2 of 2) ............................................................................ 156

Figure 2-130 Remove the low-voltage power supply (1 of 6) ......................................................................... 157

Figure 2-131 Remove the low-voltage power supply (1 of 6) ......................................................................... 158

Figure 2-132 Remove the low-voltage power supply (2 of 6) ......................................................................... 158

Figure 2-133 Remove the low-voltage power supply (3 of 6) ......................................................................... 159

Figure 2-134 Remove the low-voltage power supply (4 of 6) ......................................................................... 159

Figure 2-135 Remove the low-voltage power supply (5 of 6) ......................................................................... 160

Figure 2-136 Remove the low-voltage power supply (6 of 6) ......................................................................... 160

Figure 2-137 Remove the DC controller PCA and tray (1 of 3) ...................................................................... 161

Figure 2-138 Remove the DC controller PCA and tray (2 of 3) ...................................................................... 162

Figure 2-139 Remove the DC controller PCA and tray (3 of 3) ...................................................................... 162

Figure 2-140 Remove the high-voltage power supply lower (1 of 7) .............................................................. 163

Figure 2-141 Remove the high-voltage power supply lower (2 of 7) .............................................................. 164

Figure 2-142 Remove the high-voltage power supply lower (3 of 7) .............................................................. 165

Figure 2-143 Remove the high-voltage power supply lower (4 of 7) .............................................................. 165

Figure 2-144 Remove the high-voltage power supply lower (5 of 7) .............................................................. 166

Figure 2-145 Remove the high-voltage power supply lower (6 of 7) .............................................................. 166

Figure 2-146 Remove the high-voltage power supply lower (7 of 7) .............................................................. 167

Figure 2-147 Reinstall the high-voltage power supply lower .......................................................................... 167

Figure 2-148 Remove the developing-disengagem ent m oto r ....... ... ................. ... .... .. .................. ... .. .... ......... 168

Figure 2-149 Remove the exhaust fan and fan duct (1 of 3) .......................................................................... 169

Figure 2-150 Remove the exhaust fan and fan duct (2 of 3) .......................................................................... 170

Figure 2-151 Remove the exhaust fan and fan duct (3 of 3) .......................................................................... 170

Figure 2-152 Reinstall the exhaust fan and fan duct ..................................................................................... 171

Figure 2-153 Remove the pickup motor ............. .... .... ......................... .... .... .... ........................ ..... .................. 172

Figure 2-154 Remove the lifter-drive assembly (1 of 2) ................................................................................. 173

Figure 2-155 Remove the lifter-drive assembly (2 of 3) ................................................................................. 174

Figure 2-156 Remove the lifter-drive assembly (3 of 3) ................................................................................. 174

Figure 2-157 Remove the lifter base assembly (1 of 2) ................................................................................. 175

Figure 2-158 Remove the lifter base assembly (2 of 2) ................................................................................. 176

ENWW xxv

Figure 2-159 Reinstall the lifter base assembly (1 of 2) ................................................................................. 176

Figure 2-160 Reinstall the lifter base assembly (2 of 2) ................................................................................. 177

Figure 2-161 Remove the tray-pickup drive assembly (1 of 3) ...................................................................... 178

Figure 2-162 Remove the tray-pickup drive assembly (2 of 3) ...................................................................... 179

Figure 2-163 Remove the tray-pickup drive assembly (3 of 3) ...................................................................... 179

Figure 2-164 Remove the tray-pickup assembly (1 of 11) ............................................................................. 180

Figure 2-165 Remove the tray-pickup assembly (2 of 11) ............................................................................. 181

Figure 2-166 Remove the tray-pickup assembly (3 of 11) ............................................................................. 181

Figure 2-167 Remove the tray-pickup assembly (4 of 11) ............................................................................. 182

Figure 2-168 Remove the tray-pickup assembly (5 of 11) ............................................................................. 182

Figure 2-169 Remove the tray-pickup assembly (6 of 11) ............................................................................. 183

Figure 2-170 Remove the tray-pickup assembly (7 of 11) ............................................................................. 183

Figure 2-171 Remove the tray-pickup assembly (8 of 11) ............................................................................. 184

Figure 2-172 Remove the tray-pickup assembly (9 of 11) ............................................................................. 184

Figure 2-173 Remove the tray-pickup assembly (10 of 11) ........................................................................... 185

Figure 2-174 Remove the tray-pickup assembly (11 of 11) ........................................................................... 185

Figure 2-175 Remove the las er/scanner assembly (Y/M) (1 of 5) ........................................................... ...... 187

Figure 2-176 Remove the las er/scanner assembly (Y/M) (2 of 5) ........................................................... ...... 187

Figure 2-177 Remove the las er/scanner assembly (Y/M) (3 of 5) ........................................................... ...... 188

Figure 2-178 Remove the las er/scanner assembly (Y/M) (4 of 5). .......................................................... ...... 189

Figure 2-179 Remove the las er/scanner assembly (Y/M) (5 of 5) ........................................................... ...... 189

Figure 2-180 Remove the laser/scanner assembly (C/Bk) (1 of 5) ................................................................ 191

Figure 2-181 Remove the laser/scanner assembly (C/Bk) (2 of 5) ................................................................ 191

Figure 2-182 Remove the laser/scanner assembly (C/Bk) (3 of 5) ................................................................ 192

Figure 2-183 Remove the laser/scanner assembly (C/Bk) (4 of 5) ................................................................ 192

Figure 2-184 Remove the laser/scanner assembly (C/Bk) (5 of 5) ................................................................ 193

Figure 2-185 Reinstall the PGC actuators (1 of 5) ......................................................................................... 193

Figure 2-186 Reinstall the PGC actuators (2 of 5) ......................................................................................... 194

Figure 2-187 Reinstall the PGC actuators (3 of 5) ......................................................................................... 194

Figure 2-188 Reinstall the PGC actuators (4 of 5) ......................................................................................... 195

Figure 2-189 Reinstall the PGC actuators (5 of 5) ......................................................................................... 195

Figure 2-190 Remove the high-voltage power supply upper (1 of 2) ............................................................. 196

Figure 2-191 Remove the high-voltage power supply upper (2 of 2) ............................................................. 197

Figure 2-192 Reinstall the high-voltage power suppl y upper ..... .................. ................. .................. ............... 198

Figure 2-193 Remove the yellow, magenta, cyan, and black drum motors ................................................... 199

Figure 2-194 Remove the fuser motor ........................................................................................................... 201

Figure 2-195 Remove the ITB motor (1 of 2) ................................................................................................. 202

Figure 2-196 Remove the main-drive assembly (1 of 6) ................................................................................ 204

Figure 2-197 Remove the main-drive assembly (2 of 6) ................................................................................ 204

Figure 2-198 Remove the main-drive assembly (3 of 6) ................................................................................ 205

Figure 2-199 Remove the main-drive assembly (4 of 6) ................................................................................ 205

Figure 2-200 Remove the main-drive assembly (5 of 6) ................................................................................ 206

Figure 2-201 Remove the main-drive assembly (6 of 6) ................................................................................ 206

Figure 2-202 Reinstall the main-drive assembly (1 of 7) ................................................................................ 207

xxvi ENWW

Figure 2-203 Reinstall the main-drive assembly (2 of 7) ................................................................................ 207

Figure 2-204 Reinstall the main-drive assembly (3 of 7) ................................................................................ 208

Figure 2-205 Reinstall the main-drive assembly (4 of 7) ................................................................................ 209

Figure 2-206 Reinstall the main-drive assembly (5 of 7) ................................................................................ 209

Figure 2-207 Reinstall the main-drive assembly (6 of 7) ................................................................................ 210

Figure 2-208 Reinstall the main-drive assembly (7 of 7) ................................................................................ 210

Figure 2-209 Remove the fuser-drive assembly (1 of 7) ................................................................................ 212

Figure 2-210 Remove the fuser-drive assembly (2 of 7) ................................................................................ 212

Figure 2-211 Remove the fuser-drive assembly (3 of 7) ................................................................................ 213

Figure 2-212 Remove the fuser-drive assembly (4 of 7) ................................................................................ 213

Figure 2-213 Remove the fuser-drive assembly (5 of 7) ................................................................................ 214

Figure 2-214 Remove the fuser-drive assembly (6 of 7) ................................................................................ 214

Figure 2-215 Remove the fuser-drive assembly (7 of 7) ................................................................................ 215

Figure 2-216 Reinstall the fuser-drive asse mbly ..... ... ........................ ....................... ....................... .............. 215

Figure 2-217 Remove the front door (optional paper feeder) (1 of 2) ............................................................ 216

Figure 2-218 Remove the front door (optional paper feeder) (2 of 2) ............................................................ 217

Figure 2-219 Remove the rear cover (optional paper feeder) ........................ ...................... .......................... 218

Figure 2-220 Remove the right-front cover (optional paper feeder) .............................................................. 219

Figure 2-221 Remove the right door (optional paper feeder) (1 of 3) ............................................................ 220

Figure 2-222 Remove the right door (optional paper feeder) (2 of 3) ............................................................ 220

Figure 2-223 Remove the right door (optional paper feeder) (3 of 3) ............................................................ 221

Figure 2-224 Remove the left cover (optional paper feeder) (1 of 3) ............................................................. 222

Figure 2-225 Remove the left cover (optional paper feeder) (2 of 3) ............................................................. 223

Figure 2-226 Remove the left cover (optional paper feeder) (3 of 3) ............................................................. 223

Figure 2-227 Remove the right cover (optional paper feeder) ...................................................................... 224

Figure 2-228 Remove the rear-right cover (optional paper feeder) ............................................................... 225

Figure 2-229 Remove the pickup assembly (optional paper feeder) (1 of 5) ................................................. 226

Figure 2-230 Remove the pickup assembly (optional paper feeder) (2 of 5) ................................................. 227

Figure 2-231 Remove the pickup assembly (optional paper feeder) (3 of 5) ................................................. 227

Figure 2-232 Remove the pickup assembly (optional paper feeder) (4 of 5) ................................................. 228

Figure 2-233 Remove the pickup assembly (optional paper feeder) (5 of 5) ................................................. 228

Figure 2-234 Remove the lifter assembly (optional paper feeder) (1 of 2) ..................................................... 229

Figure 2-235 Remove the lifter assembly (optional paper feeder) (2 of 2) ..................................................... 229

Figure 2-236 Remove the lifter-drive asse mbl y (opti onal pape r feeder ) (1 of 2) ........................... ................. 230

Figure 2-237 Remove the lifter-drive asse mbl y (opti onal pape r feeder ) (2 of 2) ........................... ................. 230

Figure 2-238 Remove the pickup motor assembly (optional paper feeder) (1 of 2) ....................................... 231

Figure 2-239 Remove the pickup motor assembly (optional paper feeder) (2 of 2) ....................................... 231

Figure 2-240 Remove the controller PCA (optional paper feeder) (1 of 2) .................................................... 232

Figure 2-241 Remove the controller PCA (optional paper feeder) (2 of 2) .................................................... 232

Figure 3-1 Diagnostic test (1 of 2) .................................................................................................................. 243

Figure 3-2 Diagnostic test (2 of 2) .................................................................................................................. 244

Figure 3-3 Engine-test button ......................................................................................................................... 245

Figure 3-4 Test the TOP sensor (1 of 2) ........................................................................................................ 247

Figure 3-5 Test the TOP sensor (2 of 2) ........................................................................................................ 247

ENWW xxvii

Figure 3-6 Test the loop sensors .................................................................................................................... 248

Figure 3-7 Test the fuser delivery sensor (1 of 2) .......................................................................................... 249

Figure 3-8 Test the fuser delivery sensor (2 of 2) .......................................................................................... 249

Figure 3-9 Test the duplex re-pickup sensor ................... ..... .... .............................. ..... ..... ..... ......................... 250

Figure 3-10 Test the output-bin-full sensor .................................................................................................... 251

Figure 3-11 Test the fuser pressure-release sensor ......... ... ... .... .................. ... .... ... ................... ... ... .... .......... 253

Figure 3-12 Test the primary transfer-roller-disengagement sensor (1 of 4) ................................................. 254

Figure 3-13 Test the primary transfer-roller-disengagement sensor (2 of 4) ................................................. 254

Figure 3-14 Test the primary transfer-roller-disengagement sensor (3 of 4) ................................................. 255

Figure 3-15 Test the primary transfer-roller-disengagement sensor (4 of 4) ................................................. 255

Figure 3-16 Media sensor .............................................................................................................................. 256

Figure 3-17 Test the front-door switch ........................................................................................................... 257

Figure 3-18 Test the right door switch ............................................................................................................ 258

Figure 3-19 Test the Tray 1 media-present sensor ...................... ... .... .... .... ....................... ... .... .... ................ 261

Figure 3-20 Test the tray 2 paper-present sensor .................... ..... ............................. ..... ..... ..... .................... 262

Figure 3-21 Tray 2 paper surface 1 and 2 ...................................................................................................... 263

Figure 3-22 Test the Tray 2 paper size switches ........................................................................................... 264

Figure 3-23 Test the Tray 3 feed sensor ........................................................................................................ 265

Figure 3-24 Test the new ITB sensor ......................... .... ..... ... ..... ......................... ..... ... ..... ............................. 271

Figure 3-25 Test the new ITB sensor ......................... .... ..... ... ..... ......................... ..... ... ..... ............................. 271

Figure 3-26 Test the right door switch ............................................................................................................ 272

Figure 3-27 Product cross section .................................................................................................................. 277

Figure 3-28 Optional paper feeder (1 x 500-sheet) ........................................................................................ 278

Figure 3-29 Optional paper feeder (3 x 500-sheet) ........................................................................................ 279

Figure 3-30 Formatter PCA ............................................................................................................................ 280

Figure 3-31 DC controller connector locations ............................................................................................... 281

Figure 3-32 Controller PCA connectors ........ .................. ... ... .... .................. .. ... .... ................. .... .. ... ................ 283

Figure 3-33 External component locations ..................................................................................................... 284

Figure 3-34 Major component locations (1 of 3) ............................................................................................ 285

Figure 3-35 Major component locations (2 of 3) ............................................................................................ 286

Figure 3-36 Major component locations (3 of 3) ............................................................................................ 287

Figure 3-37 Motors, fans, and rollers comp onen t loc ati ons ................. ............... .............. ............... .............. 288

Figure 3-38 PCA component locations .......................................................................................................... 289

Figure 3-39 Optional paper feeder (1 x 500- sheet) component locations (1 of 2) ......................................... 290

Figure 3-40 Optional paper feeder (1 x 500- sheet) component locations (2 of 2) ......................................... 291

Figure 3-41 Optional paper feeder (3 x 500- sheet) component locations (1 of 2) ......................................... 292

Figure 3-42 Optional paper feeder (3 x 500- sheet) component locations (2 of 2) ......................................... 293

Figure 3-43 General timing chart ................................ ...................................... ....... ...... ....... .......................... 294

Figure 3-44 General circuit diagram (1 of 2) .................................................................................................. 295

Figure 3-45 General circuit diagram (1 of 2) .................................................................................................. 295

Figure 3-46 Paper feeder circuit diagram (1 X 500-sheet) ............................................................................. 296

Figure 3-47 Paper feeder circuit diagram (3 X 500-sheet) ............................................................................. 297

Figure 3-48 Print-quality troubleshootin g pro cedure ...... ... ................... ... .... ................... ... ... ... ....................... 302

Figure 3-49 Yellow print-quality troubleshooti ng p age ................... ................... ................... .......................... 303

xxviii ENWW

Figure 3-50 Yellow comparison page ............................................................................................................. 303

Figure 3-51 Black print-quality troubl eshoo ting page .......................... ........................ ...................... ............. 304

Figure 3-52 Configuration page ..................................................................................................................... 307

Figure 3-53 HP embedded Jetdirect page ........ ... ... .................. ... ... ... .................. .. .... ... ................. ... ............. 309

Figure 3-54 Embedded protocol page ........................................................................................................... 310

Figure 3-55 Repetitive defects ruler ............................................................................................................... 312

Figure 3-56 Sample event log ........................................................................................................................ 377

Figure 3-57 Common causes of jams (by area) ............................................................................................. 384

Figure 3-58 Jam locations .............................................................................................................................. 386

Figure 4-1 External covers, panels, and doors ......... ............... .. ... .. ............... .. ... .. ............... ... ... .. .................. 432

Figure 4-2 Right door assembly ..................................................................................................................... 434

Figure 4-3 Front door assembly ..................................................................................................................... 436

Figure 4-4 Internal components 1 of 7 ........................................................................................................... 438

Figure 4-5 Internal components 2 of 7 ........................................................................................................... 440

Figure 4-6 Internal components 3 of 7 ........................................................................................................... 442

Figure 4-7 Internal components 4 of 7 ........................................................................................................... 444

Figure 4-8 Internal components 5 of 7 ........................................................................................................... 446

Figure 4-9 Internal components 6 of 7 ........................................................................................................... 448

Figure 4-10 Internal components 7 of 7 ......................................................................................................... 450

Figure 4-11 Cassettes 2-5 .............................................................................................................................. 452

Figure 4-12 Paper pickup assembly ............................................................................................................... 454

Figure 4-13 Tray 1 paper pickup assembly .................................................................................................... 456

Figure 4-14 Registration assembly ................................................................................................................ 458

Figure 4-15 Secondary transfer assembly .............. ................. .... ... .. .................. ... ... ... .................. ............... 460

Figure 4-16 Delivery assembly ........................ ............................... ..... ..... ..... ................................................ 462

Figure 4-17 Fuser assembly ........................................................................................................................... 464

Figure 4-18 PCAs ........................................................................................................................................... 466

Figure 4-19 Paper feeders ............................................................................................................................. 468

Figure 4-20 Paper feeder external covers, panels, and doors ....................................................................... 470

Figure 4-21 1 X 500 paper feeder main body ................................................................................................ 472

Figure 4-22 3 X 500 paper feeder main body ................................................................................................ 474

ENWW xxix

xxx ENWW

1 Theory of operation

Basic operation

●

Engine-control system

●

Laser/scanner system

●

Image-formation system

●

Pickup, feed, and delivery system

●

Jam detection

●

Optional paper feeder

●

ENWW 1

Basic operation

The product routes all high-level processes through the formatter, which stores font information, processes the print image, and co mm uni cates with the host computer .

The basic product opera tio n com pr ises the foll owing systems:

The engine-control system, which includes the power supply and the DC controller printed circuit

●

assembly (PCA) The laser/scanner system, which forms the latent image on the photosensitive drum

●

The image-formation system, which transfers a toner image onto the paper

●

The media feed system, which uses a system of rollers and belts to transport the paper through

●

the product Option (optional paper feeder)

●

Figure 1-1 Relationship between the main product systems

Laser/scanner system

Engine control system

Image-formation system

Media-feed system

Option

2 Chapter 1 Theory of operation ENWW

Sequence of operation

The DC controller PCA controls the operating sequence, as described in the following table.

Table 1-1 Sequence of operation

Period Duration Description

Waiting From the time the power is turned on, the

door is closed, or when the product exits Sleep mode until the product is ready for printing

Standby From the end of the waiting sequence or

the last rotation until the formatter receives a print command or until the product is turned off

Initial rotation From the time the formatter receives a

print command until the paper enters the paper path

Printing From the time the first sheet of paper

enters the paper path until the last sheet has passed through the fuser

Heats the fuser sleeve in the fuser

●

Pressurizes the pressure roller in

●

the fuser Detects the print cartridges

●

Moves the ITB and developing unit

●

to the home position Cleans the ITB and secondary

●

transfer roller The product is in the READY state.

●

The product enters Sleep mode if

●

the sleep command is received from the formatter.

The product calibrates if it is time for

●

an automatic calibration. Activates the high-voltage power

●

supply Prepares each laser/scanner unit

●

Warms the fuser to the correct

●

temperature Forms the image on the

●

photosensitive drums Transfers the toner to the paper

●

Fuses the toner image onto the

●

paper

Last rotation From the time the last sheet of paper

exits the fuser until the motors stop rotating

Moves the last printed sheet into the

●

output bin Stops the high-voltage power

●

supply Stops each laser/scanner unit

●

If another print command is

●

received, the product enters the initial rotation period when the last rotation is complete.

ENWW Basic operation 3

Engine-control system

The engine-control system receives commands from the formatter and interacts with the other main systems to coordinate all product functions. The engine-control system consists of the following components:

DC controller

●

Low-voltage power suppl y

●

High-vol tage power supply

●

Fuser control

●

Figure 1-2 Engine-control syst em

Formatter

ENGINE CONTROL SYSTEM

DC controller

Low-voltage power supply

High-voltage power supply

Fuser control

LASER SCANNER SYSTEM

IMAGE-FORMATION SYSTEM

MEDIA FEED SYSTEM

OPTION

4 Chapter 1 Theory of operation ENWW

DC controller

The DC controller controls the operational sequence of the product.

Figure 1-3 DC controller block diagram

Motor

Solenoid

Secondary

transfer roller

Print cartridge

(Y/M/C/Bk)

Motor

Fan

Photointerrupter

ITB unit

AC input

High-voltage

power supply T

High-voltage

power supply D

Fuser

Low-voltage

power supply

DC controller

ICB

Fan

Motor

Clutch

Solenoid

Switch

Photointerrupter

Sensor

LED

Option

Control panel

NVRAM

Solenoids

Table 1-2 Solenoids

Laser scanner unit

Component a bbreviati on Component name

SL1 Primary transfer roller disengagement solenoid SL2 Duplex reverse solenoid (HP Color LaserJet CP4525dn, HP Color LaserJet CP4025dn, and

HP Color LaserJet CP4525xh only) SL3 Multipurpose-tray pickup solenoid SL4 Cassette pickup solenoid

Formatter

ENWW Engine-control s y ste m 5

Clutches

Component abbreviation Component name

Switches

CL1 Duplex re-pickup clutch (HP Color LaserJet CP4525dn, HP Color LaserJet CP4025dn, and HP

Color LaserJet CP4525xh only)

Table 1-3 Switches

Component abbreviation Component name

SW1 5V interlock switch SW2 24V interlo ck switch SW3 Power switch SW4 Cassette media size switch SW5 Front door switch SW6 Right door switch Test print switch

6 Chapter 1 Theory of operation ENWW

Sensors

Table 1-4 Sensors

Component a bbreviati on Component name

NPLED Media sensor SR1 Yellow drum home position sensor SR2 Magenta drum home position sensor SR3 Cyan drum home position sensor SR4 Black drum home position sensor SR5 Fuser delivery sensor SR6 Output bin full sensor SR7 Fuser pressure release sensor SR8 MP-tray-media-presence sensor SR9 Primary-transfer-roller disengagement sensor SR10 New ITB sensor SR11 Developer alienation sensor SR14 Loop sensor 1 SR15 Loop sensor 2 SR20 TOP (top of page) sensor SR22 Duplex re-pickup sensor (HP Color LaserJet CP4525dn, HP Color LaserJet CP4025dn, and

SR23 Tray 2 paper surface 1 sensor SR24 Tray 2 paper surface 2 sensor SR25 Tray 2 paper present sensor RD sensor Environment sensor (temperature and humidity) Yellow toner-level sensor Magenta toner-level sensor Cyan toner-level sensor Black toner-level sensor Residual toner full sensor TH4 Laser scanner temperature sensor

HP Color LaserJet CP4525xh only)

ENWW Engine-control s y ste m 7

Motors

The product has 13 motors. The motor s drive the co mpo nents in the paper-feed and imag e- for mat ion systems.

Table 1-5 Motors

Abbreviation Name Purpose Failure detection

M1 ITB motor Drives the ITB and residual

toner feed screw

M2 Fuser motor Drives the fuser sleeve,

pressure roller, fuser pressure roller, and primary transfer roller disengagement

M3 Y drum motor Drives the photosensitive

drum (yellow), developing roller (yellow), and primary charging roller (yellow)

M4 M drum motor Drives the photosensitive

drum (magenta), developing roller (magenta), and primary charging roller (magenta)

M5 C drum motor Drives the photosensitive

drum (cyan), developing roller (cyan), and primary charging roller (cyan)

M6 Bk drum motor Drives the photosensitive

drum (black), developing roller (black), and primary charging roller (black)

M7 Lifter motor Drives the lifter for the

cassette

Yes

M8 Cyan/black scanner motor Drives the scanner mirror in

M9 Yellow/magenta scanner

motor

M10 Developing disengagement

motor

M11 Duplex reverse motor (HP

Color LaserJet CP4525dn, HP Color LaserJet CP4025dn , and HP Color LaserJet CP4525xh only)

M12 Residual toner-feed motor Drives the residual toner feed

M13 Pickup motor Drives the cassette pickup

the cyan/black laser scanner Drives the scanner mirror in

the yellow/magenta laser scanner

Drives the developing unit disengagement

Drives the duplex reverse roller and duplex feed roller

screw

roller, MP tray pickup roller, feed roller, and cassette separation roller

Yes

8 Chapter 1 Theory of operation ENWW

Fans

The DC controller determines if a motor has failed and notifies the formatter when it encounters the following conditions :

Startup failure: the motor does not reach a specified speed within a specified time from when the

●

motor starts. Rotational failure: the rotational speed of the motor is not in the specified range for a specified time

●

after the motor reaches a specified speed. Lock detection (for the residual toner feed motor): the value of the motor drive signal voltage is not

●

in the specified range for a specified time.

The product has four fans for preventing the temperature from rising in the product.

Table 1-6 Fans

Abbreviation Name Cooling area Type Speed

FM1 Power supply fan Around the power

supply unit FM2 Cartridge fan Around the cartridges Intake Full/half FM3 Delivery fan Around the delivery unit Intake Full/half FM4 Exhaust fan 1 Around the cartridge Exhaust Full/half

Intake Full/half

The DC controller determines if there is a fan failure and notifies the formatter if the fan locks for a specified time from when the fan starts.

ENWW Engine-control s y ste m 9

High-voltage power supply

The DC controller controls the high-voltage power supply to generate biases. The high-voltage power supply delivers the high-voltage biases to the following components used to transfer toner during the image-formation pr oc es s:

Primary-chargin g roller (in the cart ri dge )

●

Developing roller ( in the cartridge)

●

Primary-transfer ro ller

●

Secondary-transfer r oller

●

Figure 1-4 High-voltage power supply circuits

Primary transfer roller

Developing bias

circuit

Primary transfer

bias circuit

High-voltage power supply D

High-voltage power supply T

Secondary transfer

bias circuit

ITB

Secondary transfer roller

DC controller

Print cartridge

Primary charging

bias circuit

The high-voltage p ower supply contains sever al s epar at e ci rc ui ts.

Table 1-7 High-voltage power supply circuits

Circuit Description

Primary-charging-bias generation The primary charging bias negatively charges the surface of the photosensitive drum

to prepare for image formation. The primary-charging-bias circuit in the high-voltage power supply generates the biases for each color.

Developing-bias generation The developing bias adheres toner to an electrostatic latent image formed on the

photosensitive drum. The developing-bias circuit in the high-voltage power supply generates the biases for each color.

10 Chapter 1 Theory of operation ENWW

Table 1-7 High-voltage power supply circuits (continued)

Circuit Description

Primary-transfer-bias generation The primary transfer bias transfers the toner from each photosensitive drum onto

the ITB. The primary transfer bias circuit in the high-voltage power supply generates the biases for each color.

Secondary-transfer-bias generation The secondary transfer bias transfers the toner image from the ITB onto the paper.

The secondary transfer bias circuit in the high-voltage power supply generates the bias. The reversed bias transfers residual toner on the secondary transfer roller back to the ITB. The residual toner on the ITB is deposited in the toner collection box.

ENWW Engine-control s y ste m 11

Low-voltage power supply

The low-voltage power-supply circuit converts the AC power from the wall receptacle into the DC voltage that the product components use. The product has two low-voltage power-supplies for 110 Volt or 220 Volt input.

Figure 1-5 Low-voltage power-supply circuit

AC input

Fuse

DC controller

Fuse

Noise filter

Rectifying

circuit

+12V

generation

circuit

Low-voltage power supply

Noise filter

circuit

Protection circuit

Remote switch

control circuit

Power switch

Zerocross

circuit

+24V

generation

circuit

Fuser control

Protection circuit

+3.3V

generation

circuit

+5V

generation

circuit

PSTYP100

ZEROX

24RMT

+24VA

+5VB

+3.3V

Switching

PWROFF

PWRSWON

+12VA

circuit

ICB

+24VB

SW2

SW1

+5VC

+3.3VS

Formatter

The low-voltage power supply converts the AC power into three DC voltages, which it then subdivides, as described in the followin g tabl e.

Table 1-8 Converted DC voltages

Main DC voltage Sub-voltage Behavior

+24 V +24 VA Constantly supplied

12 Chapter 1 Theory of operation ENWW

Table 1-8 Converted DC voltages (continued)

Main DC voltage Sub-voltage Behavior

+24 VB Interrupted when the front door or right

door open +5 V +5 VB Constantly supplied +5 VC Interrupted when the front door or right

+3.3 V 3.3 V Constantly supplied

3.3 VS Stopped during Sleep (powersave)

Overcurrent/overvoltage protection

The low-voltage power su ppl y sto ps su ppl yi ng the DC voltage to the product components whenever it detects excessive current or abnormal voltage from the power source. If DC voltage is not being supplied from the low-voltage power supply, the protective function might be running. In this case, turn the power off and unplug the power cord. Do not turn the power switch on until the root cause is found. The DC controller notifies the formatter of a low-voltage power supply failure when the protective function is activated. In addition, the low-voltage power supply circuit and the fuser control unit have a fuse to protect against overcurrent. If overcurrent flows into the AC line, the fuse blows to stop AC power.

Safety

For personal safety, the produ ct int er rupts 24 VB power to the f use r, high- v olt age po wer sup ply , and motors, in addition to +5 VC to the laser scanners when the front or right door is opened. The power switch is on the dc line so that the ac power flows even if the power switch is turned off. Unplug the power cord before disas se mbl in g the pr odu ct.

door open

mode

Voltage detection

The product detects the power supply voltage that is connected to the product. The DC controller monitors the POWER SUPPLY VOLTAGE (PSTYP100) signal and detects power supply voltage, whether 100 V or 200 V, to control the fuser operation.

Sleep (powersave) mode

Sleep mode conserves energy by stopping the power to several components when the product is idle. If the DC controller detects voltage that is too high when the product is in Sleep mode, it determines that the low-voltage power supply has failed, and it notifies the formatter.

Low-voltage power supply failure

The DC controller determine s a low-vo ltage power supply failure and not ifi es th e for matt er when the low-voltage power su ppl y doe s not su ppl y + 24 V.

ENWW Engine-control s y ste m 13

Fuser control

The fuser heater-control circuit and the fuser heater safety circuit control the fuser temperature according to commands from the DC controll er.

Figure 1-6 Fuser components

TH2

Table 1-9 Fuser components

Type of component Abbreviation Name Function

TH1

Fuser sleeve

TP1

TH3

CONTROL signal

FUSER TEMPERATURE signal

Pressure roller

Low-voltage power

FUSER HEATER

supply unit

Fuser heater

control circuit

DC controller

Fuser heater

safety circuit

Heaters H1 Fuser heater Heats the fuser sleeve. Thermistors (Contact type)

Thermoswitches (Contact type)

TH1 Main thermistor Detects the center temperature of

the fuser sleeve.

TH2 Sub thermistor 1 Detects the temperature at one

end of the fuser heater.

TH3 Sub thermistor 2 TP1 For the fuser heater Controls the fuser-roller main

heater

14 Chapter 1 Theory of operation ENWW

Fuser temperature control

The fuser temperature co ntr ol ma inta ins the tar get su rfa ce tempe ra tur e of the fuser sl eev e.

Figure 1-7 Fuser temperature-control circuit

Fuser

Fuser sleeve unit

TH1 TH2 TH3

Pressure

roller

H1: Fuser heater TP1: Thermoswitch TH1: Main thermistor TH2: Sub thermistor 1 TH3: Sub thermistor 2

TP1

Fuse

Fuser heater control circuit

Current

detection

circuit

Fuser heater safety circuit

Relay

Fuser heater safety circuit

Low-voltage power supply

Zerocross

circuit

Relay

control

circuit

Relay

FSR_CURRMS

Fuser control circuit

/ZEROX

FSRD1

/RLD

FSRSAFE1

FSRSAFE2

/FSRNEW

/FSRSNS FSRTH3 FSRTH2 FSRTH1

CPU

Fuser heater

safety circuit

Fuser sleeve temperature p rotection

The fuser heater controls the temperature of the fuser sleeve. The DC controller detects the center area temperature by monit ori ng the main the rm ist or. The DC control ler co ntr ols the F IXING HEATER CONTROL (FSRD1) signal, so that the fuser sleeve remains at the targeted temperature.

Protective function: The protective function detects rising temperatures in the fuser and interrupts

●

power to the fuser heater. The following four protective components prevent the fuser sleeve and pressure roller from excessive rising temperature:

DC controller

◦

Fuser heater safety ci rc uit

◦

DC controller

ENWW Engine-control s y ste m 15

Current detection circ ui t

◦

Thermoswitch

◦

DC controller: The DC controller monitor s the dete cte d temp er ature of t he mai n ther mi sto r and

●

sub thermistors. The DC controller deactivates the FIXING HEATER CONTROL signal and releases the relay to interrupt powe r su ppl y to the fus er heate r und er the foll owi ng c ond iti ons :

TH1: 230° C (446° F) or higher

◦

TH2: 285° C (545° F) or higher

◦

TH3: 285° C (545° F) or higher

◦

Fuser-heater safety circuit: The fuser heater safety circuit monitors the detected temperature of

●

the sub thermistors. The fuser heater safety circuit releases the relay to interrupt powe r suppl y to the fuser heater under the following conditions:

TH2: 290° C (554° F) or higher

◦

TH3: 290° C (554° F) or higher

◦

Current-detection protection circuit: The current detection circuit monitors the current flowing

●

through the fuser heater control circu it. The c urre nt dete ction c ir cuit dea cti va tes the fus er heate r control circuit to interrupt power supply to the fuser heater when it detects the current higher than a specified value.

Thermoswitch: If the temperature in the heaters is abnormally high, and the temperature in the

●

thermoswitches exceeds a specified value, the contact to the thermoswitch breaks. Following are the thresholds for each thermos witch:

◦

NOTE: When the thermoswitches reach this temperature, the temperature on the fuser rollers is about

320° C (608° F).

Failure detection

The DC controller determines a fuser unit failure, deactivates the FIXING HEATER CONTROL signal, releases the relay to interrupt power supply to the fuser heater, and notifies the formatter of a failure status when it encounters any of following conditions:

Abnormally high temperatures: Temperatures are too high for any of the following components,

●

at any time:

◦

Abnormally low temperatures: Temperatures are too low at any of the follow ing comp one nts

●

after the product has initiali ze d.

TP1: 270° C (518° F) or higher

TH1: 230° C (446° F) or higher TH2: 285° C (545° F) or higher TH3: 285° C (545° F) or higher

TH1: 120° C (248° F) or lower

◦

TP2 or TP3: 100° C (212° F) or lower

◦

Abnormal temperature rise : The DC controller determines an abnormal temperature rise if the

●

detected temperature of TH1 does not rise 2° C within a specified time after the fuser motor is

16 Chapter 1 Theory of operation ENWW

turned on, or if the detected temperature of the thermistors does not rise to a specified temperature for a specified time after the fuser motor is turned on.

Thermistor open: The DC controller determines a thermistor open if:

●

The detected temperature of TH1 is kept at 12° C (53° F) or lower for a specified time after

◦

the fuser motor is turned on. The detected temperature of TH2 is kept at 4° C (39° F) or lower for a specified time.

◦

The detected temperature of TH3 is kept at 4° C (39° F) or lower for a specified time.

◦

Drive-circuit failu re: The DC con troller determines a drive- c ircu it fai lure:

●

If the detected power supply frequency is out of a specified range when the product is turned

◦

on or during the standby period If the current detection circuit det ects an out of specified current val ue

◦

Fuser discrepancy: The DC controller determines a fuser type mismatch when it detects an

●

unexpected power supply voltage.

Fuser unit identification

The product detects the type and presence of the fuser. The DC controller detects whether the fuser is installed and its type by monito ri ng the FIXING UNIT IDENTIFICATION (FS RSNS) signal when the product is turned on or when the right door is closed. The DC controller determines a low-voltage power supply failure and notifies the format ter when it fail s to dete ct the type or presenc e of the fus er .

NOTE: This product detects if the correct fuser for the product is installed. The fuser from a different

product (for example, the HP Color LaserJet CP 3525 Series printer) can be installed in this product, but it will not correctly function.

Fuser unit life detection

The product detects the remaining life of a fuser. The DC controller recognizes a new fuser from the NEW FIXING UNIT (/FSRNEW) signal. The DC controller determines a fuser's end of life and then notifies the formatter when a specified number of pages has been printed after the fuser was replaced.

NOTE: The product detects a new fuser using a fusible link that blows after 100 pages of printing. If

a new fuser is installed for troubleshooting purposes, be sure to remove it before printing 100 pages.

ENWW Engine-control s y ste m 17

Laser/scanner system

The laser/scanner sy s tem for ms the lat ent el ec tro sta tic ima ge on th e photo se ns iti ve dr um s ac co rd ing to the VIDEO signals sent from the formatter. The product has two laser/scanners: one for yellow and magenta and the other for cyan and black.

The main components of the laser/scanner system are the laser unit and the scanner motor unit, which are controlled by the signals sent from the DC controller.

Figure 1-8 Laser/scanner system

Photosensitive drum (Y)

BD sensor

Yellow laser

Magenta laser

Photosensitive drum (M)

Laser unit

VIDEO signal

Scanner motor unit

SCANNER MOTOR

LASER CONTROL signal

BDI signal

CONTROL signal

DC controller

Formatter

Protective glass

Scanner mirror

18 Chapter 1 Theory of operation ENWW

Laser/scanner failure

The DC controller determines that a laser/scanner has failed when any of the following conditions occurs:

Laser failure: The detected las er inten si ty doe s not match a specified value when the produc t

●

initializes. Scanner motor startup f ailu re : The scanner motor does not reach a specified rotation within a

●

specified period from when the laser scanner starts driving. Scanner-motor abnorm al rotatio n: When a specified BD interval is not detected during a print

●

operation, a BD error is determined. If the BD interval does not recover within a specified period after the BD error occurs, the pro duc t deter m ine s a scanner motor abnormal rota tion .

The laser/scanner system does not have a mechanical laser shutter. For safety reason, the product has a interlock switch. The interlock switch is turned off to interrupt +5 V power supply to the laser/scanner system, when the front or right door is open.

Protective-glass cleaners

Each laser/scanner has two ope ni ngs whic h allo w the las er beam to pass to the surface of the photosensitive drum. These ope nin gs ar e cover ed by pr otectiv e gl as s. W hen the pro tec tive glass gets dirty (for example, by pape r dus t or toner) a pr otec tiv e-gl as s cl ean er (PGC) cl eans them .

NOTE: When a glass is dirty, streaks appear on the printed page in the process direction.

The PGC is a cleaning pad which slides along the laser shutter. With the front door open, the laser shutter is positioned over the gla ss. As a print cartridge is inserted, the cl ean ing pad is pus hed down and wipes the glass. When the front door is closed after cartridge insertion, the laser shutter (and PGC) move away from the glass which allows the laser beam to pass through the glass.

When the front door is opened, the laser shutter and PGC move back into position over the glass. When the cartridge is pulled out, the cleaning pad is returned to its starting position at the front of the cartridge opening.

ENWW Laser/scanner sy ste m 19

Figure 1-9 Protective-glass cleaners (PGCs)

20 Chapter 1 Theory of operation ENWW

Image-formation system

The image-formation system creates the printed image on the paper. The system consists of the following components :

Print cartridges

●

ITB

●

Secondary transfer roller

●

Fuser

●

Laser /scanner units

●

The DC controller controls the laser scanner unit and each of the high-voltage power supplies to form the toner image on the photosensitive drum surface, according to the VIDEO signals. The toner image is then transferred to the print-m edi a and fuse d.

Figure 1-10 Image-formation system

High-voltage power supply T

Laser scanner unit

ITB

Laser scanner unit

High-voltage power supply D

Fuser

Secondary transfer roller

DC controller

Print cartridge

ENWW Image-formation sy ste m 21

Figure 1-11 Image-formation drive system

Primary

charging

roller

Developing

roller

Primary

charging

roller

Developing

roller

Developing

Primary

charging

roller

Fuser motor

Primary

charging

roller

Developing

roller

Y drum motor

M drum motor

C drum motor

Bk drum motor

ITB motor

22 Chapter 1 Theory of operation ENWW

Image-formation process

The image-formation syst em consis ts of ten s teps div id ed in to si x fun cti ona l blo ck s.

Figure 1-12 Image-formation process

: Media path : Direction of drum rotation : Block

Delivery

: Step

Fuser

ITB cleaning

9. ITB cleaning

5. Primary transfer

10. Drum cleaning

4. Developing

Developing

3. Laser beam exposure

Latent image formation

Functional block Steps Description

Latent image formation 1. Pre-exposure

2. Primary charging

1. Pre-exposure

2. Primary charging

Transfer

6. Secondary transfer

Drum cleaning

Pickup

An invisible latent image forms on the surface of the photosensitive drums.

8. Fusing

7. Separation

Registration

3. Laser-beam exposure

Development 4. Development Toner adheres to the electrostatic latent

image on the photosensitive drums.

Transfer 5. Primary transfer

6. Secondary transfer

7. Separation

Fusing 8. Fusing The toner fuses to the paper to make a

ITB cleaning 9. ITB cleaning Residual toner is removed from the ITB. Drum cleaning 10. Drum cleaning Residual toner is removed from the

The toner image transfers to the ITB and later to the paper.

permanent image.

photosensitive drums.

ENWW Image-formation sy ste m 23

Step 1: Pre-exposure

Light from the pre-exposure LED strikes the surface of the photosensitive drum to remove any residual electrical charges from the drum sur fac e.

Figure 1-13 Pre-exposure

LED

Photosensitive drum

Step 2: Primary charging

The primary-charging rol le r co ntac ts the photosensitive drum and char ges the dr um wi th neg ati ve potential.

Figure 1-14 Primary ch ar gin g

Primary charging roller

Photosensitive drum

Primary charging bias

24 Chapter 1 Theory of operation ENWW

Step 3: Laser -beam exposure

The laser beam strikes the surface of the photosensitive drum in the areas where the image will form. The negative charge neutr ali ze s in tho se ar eas, w hic h are then r ead y to ac ce pt toner.

Figure 1-15 Laser-beam exposure

Step 4: Develo pment

Toner acquires a negative ch arg e as the dev elo pin g cy li nde r co ntac ts the dev el opi ng bl ade . Bec ause the negatively charged su rface of the photosensitive drum s have been ne utr ali ze d whe re th ey ha ve been struck by the laser beam, the toner adheres to those areas on the drums. The latent image becomes visible on the surface of each drum.

Laser beam

Figure 1-16 Development

Developing blade

Developing roller

Developing bias

Photosensitive drum

ENWW Image-formation sy ste m 25

Step 5: Primary transfer

The positively charged prima ry -transfer rollers contact the ITB, giving the ITB a positive charge . The ITB attracts the negatively cha rg ed tone r fro m the su rfa ce of each ph otos ens it iv e dru m, an d the complete toner image transfers onto the ITB.

Figure 1-17 Primary trans fer

Primary transfer bias

Primary transfer roller

ITB

Photosensitive

drum

Step 6: Secondary transfer

The paper acquires a positive charge from the secondary-transfer roller, and so it attracts the negatively charged toner from the surface of the IT B. The com pl ete tone r im age trans fers onto the paper.

Figure 1-18 Secondary transfer

Secondary transfer

opposed roller

Paper

Secondary transfer bias

ITB

Secondary transfer roller

26 Chapter 1 Theory of operation ENWW

Step 7: Separation

The stiffness of the paper causes it to separate from the ITB as the ITB bends. The static-charge eliminator removes excess charge from the paper to make sure that the toner fuses correctly.

Figure 1-19 Separation

Paper

Secondary transfer roller

Step 8: Fusing

To create the permanent image, the paper passes through heated, pressurized rollers to melt the toner onto the page.

Secondary transfer

opposed roller

ITB

Static charge

eliminator

Figure 1-20 Fusing

Fuser heater

Fuser sleeve

Toner

Paper

Pressure roller

ENWW Image-formation sy ste m 27

Step 9: ITB cleaning

The cleaning blade scrapes the residual toner off the surface of the ITB. The residual toner feed screw deposits residual toner in the ton er col lecti on box .

Figure 1-21 ITB cleaning

Residual toner feed screw

Cleaning blade

Step 10: Drum cleaning

The cleaning blade scrapes the residual toner off the surface of the photosensitive drum, and toner is deposited in the toner collec tion box in the ca rtr id ge.

Figure 1-22 Drum cleaning

Cleaning blade

ITB

CRG toner collection box

Print cartridge

Each print cartridge is filled with toner and consists of the following components:

Photosensitive drum

●

Developing unit

●

Developing roller

●

Primary-chargin g ro ller

●

Photosensitive

drum

28 Chapter 1 Theory of operation ENWW

The DC controller rotates the drum motor to drive the photosensitive drum, developing roller, and the primary-charging roller.

Figure 1-23 Print-cartridge system

DC controller

M10

Developing

disengagement

motor

Developing unit

SR11: Developing disengagement sensor

SR1/SR2/SR3/SR4:

Drum home position sensor

M3/M4/M5/M6: Drum motor

Primary charging roller

Memory tag

Developing roller

The DC controller rotates the drum motor to drive the photosensitive drum, developing unit, and primary charging roller.

The memory tag is a non-volatile memory chip that stores information about the usage for the print cartridge. The product reads and writes the data in the memory tag.

ENWW Image-formation sy ste m 29

The DC controller determines a memory tag error and notifies the formatter when it fails to either read from or write to the memory tag.

Cartridge presence detection: The DC controller detects the presence of the cartridges by

●

monitoring the memory tag. The DC controller notifies the formatter when a cartridge is missing or installed in the incorr ec t slo t.

Toner level detection: The DC controll er detect s the rema ini ng ton er in a cartridge by the optical

●

detection method and then notifies the formatter of the remaining toner level. Cartridge life detection: The DC controller detects the cartridge life by monitoring the total operating

●

time or remaining toner level of the print cartridge. The DC controller determines a cartridge end of life and notifies the formatter when total operating time of the cartridge reaches a specified time or the cartridge runs out of toner.

Developing-roller engagement and disengagement

The product can print in full-color mode or in black-only mode. To print in black-only mode, the product disengages the developing rollers in the cyan, magenta, and yellow print cartridges which maximizes the life of the cartridges.

Figure 1-24 Developing-roller engagement and disengagement control

DC controller

Developing

M10

disengagement motor

Developing unit

SR11 Developing disengagement sensor

Developing unit is disengaged

Photosensitive drum

Developing disengagement cam

Developing unit is engaged

30 Chapter 1 Theory of operation ENWW

The developing-r ol ler e nga gem ent and dis engagement control ope rates as follows: When the pro duc t is turned on and when each print job is completed, all four of the developing units are disengaged from the photosensitive dr ums.

The drive of the developing disengagement motor rotates the developing disengagement cam.

●

As the cam rotates, the developing unit engages with or separates from the photosensitive drum.

●

When the print mode is full color, the developing units engage with the drums. When the print mode is black-only, only the black developing units engages with the drum.

The DC controller determines a developing disengagement motor failure and notifies the formatter when it does not detect a specified signal from the developing disengagement sensor during the developing unit engagement and dise nga gem ent operation.

Intermediate transfer belt (ITB) unit

The ITB unit accepts the toner images from the photosensitive drums and transfers the completed image to the paper. The ITB unit has the following main components:

ITB

●

ITB drive roller

●

ITB-drive roller

●

Primary-transfer ro ller

●

ITB cleaner

●

The ITB motor drives the ITB drive roller, which rotates the ITB. The motion of the ITB causes the primary transfer roller s to rota te. T he ITB cle ane r cl eans the ITB surface.

Figure 1-25 ITB unit

DC controller

ITB

ITB cleaner

ITB motor

ITB drive roller

Primary transfer roller

ENWW Image-formation sy ste m 31

Primary-transfer-roller engagement and disengagement

The sequence of the primary-transfer-roller engagement and disengagement control is as follows:

1. The fuser motor turns on the primary-transfer disengagement solenoid and rotates the primary-

transfer-roller di sen gagement cam.

2. As the cam rotates, the Y/M/C primary-transfer-roller slide plate or the Bk primary-transfer-roller

slide plate moves to the right or left, which causes the primary-transfer roller to move up or down.

3. The ITB engages with or separates from the photosensitive drum depending on the movement of

the primary-transfer rol lers .

Depending on the requirem en ts of the pr int jo b, the pri ma ry-t ra nsfer rollers engage with the ITB so it can receive toner from the photosensitive drums. The primary-transfer roller has three engagement states.

Table 1-10 Primary-transfer-roller engagement states

All rollers disengaged The ITB is disengaged from all t he four photosensitive drums. This state is the home

All rollers engaged The ITB is engaged with all four photosensitive drums. The state for full-color

Black roller engaged The ITB is engaged with only the black photosensitive drum. The state for black-

position for the ITB unit.

printing.

color mode printing .

The DC controller determines a primary-transfer-roller disengagement failure and notifies the formatter when it does not detect a signal from the prima ry -t ransfer disengagement sensor ev en tho ugh the primary-transfer di se ngag eme nt solenoid is turned on.

If the DC controller does not receive the expected signal from the ITB home-position sensor when the primary-transfer-roll er engag es or di sen gag es , but th e pr im ar y-tr ans fer-r ol ler di se ngagement motor is rotating, the DC controller dete rmine s that the primary-transfer -dis eng age men t mechanism has failed, and notifies the formatter.

The DC controller detects whether the ITB unit is new by monitoring the new ITB unit sensor. The DC controller determines the ITB unit is at end of life and notifies the formatter when a specified number of pages are printed after the ITB unit is replaced. If swapping ITB units between two products for troubleshooting purposes, be sure to return the ITB units to their original products to maintain the correct life count.

NOTE: A new ITB has a flag that causes the ITB life counter to be reset. When an ITB is installed in

the product, it cannot be removed and used again as a new ITB. The DC controller detects the presence of an ITB unit by monitoring the primary-transfer-roller

disengagement sensor. The DC controller turns on the primary-transfer disengagement solenoid for specified times during an initial rotation period when the following events occur:

The product is turned on.

●

The product exits sleep mode.

●

The door is closed.

●

The DC controller determines the absences of an ITB unit and notifies the formatter when it does not detect a specified signal from the new primary transfer-rol le r disen gagement sensor.

32 Chapter 1 Theory of operation ENWW

Figure 1-26 Three states of primary-trans fer -r ol ler eng agement and disengageme nt

DC controller

Fuser motor

SL1

Primary transfer disengagement solenoid

Photosensitive drum

ITB

SR9:

Primary transfer

disengagement sensor

Primary transfer roller

Primary transfer roller disengagement cam

YMC primary transfer roller slide plate

Bk primary transfer roller slide plate

ENWW Image-formation sy ste m 33

ITB cleaning

The cleaning blade in the ITB cleaner scrapes the residual toner off the ITB surface. The residual toner feed screw deposits the residual toner to the residual toner feed unit. The ITB motor and the residual toner feed motor drive the screw. The DC control detects whether the toner collection box is full, using the residual-toner full sensor, and then notifies the formatter.

Figure 1-27 ITB cleaning process

Cleaning blade

ITB cleaner

ITB motor

Calibration

The product calibrates itself to maintain excellent print quality. Calibration corrects color-misregistration and color-densi t y va ri ation.

During calibration, the pr odu ct pla ce s a specific pattern of toner on the surface of the ITB. Sens or s at the end of the ITB read the toner pattern to deter mi ne if adj ust men ts ar e nec essary.

Residual toner

feed screw

M12

Residual toner feed motor

DC controller

Residual toner full sensor

ITB

Residual toner feed unit

Toner collection box

NOTE: The product performs a drum-speed adjustment (DS A) dur in g the ful l c ali bratio n operation.

The DSA compensates for variations between each drum and the speed of the ITB surface.

34 Chapter 1 Theory of operation ENWW

Color-misregistration control

Internal variations in the laser/scanners can cause the toner images to become misaligned. The colormisregistration control corrects the fo ll owi ng pr ob lem s:

Horizontal scanning sta rt pos iti on

●

Horizontal scanning magnification

●

Vertical scanning start position

●

The DC controller forms a pattern of toner on the surface of the ITB and measures a misaligned length with the RD sensor.

Figure 1-28 Toner patterns for calibrat ion

RD sensor

The DC controller signals the formatter to perform the color-misregistration control when one of the following events oc cu r:

A cartridge or the ITB is replaced.

●

A specified number of pages have printed.

●

The formatter sends a command.

●

The DC controller determines an RD sensor failure and notifies the formatter if it detects data from the RD sensor that is not in a specified range, when the product is turned on or when the colormisregistration cont rol s tarts.

ITB

Pattern of toner

Image-stabilization control

NOTE: The product contains a thermal sensor, locat ed with in the TCU le vel dete ction s ens or , whic h

monitors the temperature in the cartridge area and uses this information to make adjustments during CPR control.

ENWW Image-formation sy ste m 35

Environmental change s or deterior at ion of the photosensitive drums and toner can cause v ari ati ons in the image density. The image-stabilization control reduces these fluctuations.

Table 1-11 Image-stabilization controls

Image density control (DMAX) This control corrects variations in image density related to deterioration of the

Image halftone control (DHALF) The formatter performs this control to calibrate the halftone, based on the halftone-

photosensitive drum or the toner. The DC controller adjusts the high-voltage biases to correct the problem under the following conditions:

The image-stabilization control calibrates each high-voltage bias to stabilize the fluctuations in image density caused by deterioration of the photosensitive drums or toner or because of environmental changes. The DC controller determines the product's environment based on the surrounding temperature and humidity data from the environment sensor. The DC controller calibrates the biases according to the detected environment and usage condition of the print cartridge to obtain an appropriate image. The DC controller determines an environment sensor failure and notifies the formatter when it detects environmental data from the environment sensor with out of specified value. The DC controller commands the formatter to control the image density under the following conditions

The temperature of the main thermistor is too low when the product is turned

●

on. A print cartridge or the ITB is replaced.

●

A specified number of pages have printed.

●

After a specific period of the completion of a previous DMAX

●

The environment changes for a specified condition after a previous DMAX.

●

density measurements, under the following conditions:

The formatter sends a command.

●

DMAX is completed.

●

The DC controller determines an RD sensor failure and notifies the formatter if it detects data from the RD sensor out of a specified range.

The DC controller determines a RD sensor failure and notifies the formatter if it detects an out-ofspecified-data value from the RD sensor when the product is turned on or when the color misregistration control start s.

36 Chapter 1 Theory of operation ENWW

Pickup, feed, and delivery system

The pickup, feed, and delivery system uses a series of rollers to move the paper through the product.

Figure 1-29 Paper path

Duplex model only Simplex media path

Duplex media path

Reverse roller

Pressure roller

Fuser sleeve

Secondary transfer roller

MP tray pickup roller

Cassette feed roller

Cassette pickup roller

MP tray separation pad

Cassette separation roller

ENWW Pickup, feed, and delivery system 37

Figure 1-30 Switches and sensors for the pickup, feed, and delivery system

Duplex model only

SR6

SR5

SR14

SR15

SR20

SW4

SR25

SR23

SR24

SR22

Media sensor

SR8

Table 1-12 Switches and sensors for the pickup, feed, and delivery system

Abbreviation Component

SR5 Fuser delivery sensor SR6 Delivery tray media full sensor SR8 MP tray media presence sensor SR14 Loop sensor 1 SR15 Loop sensor 2 SR20 TOP (top of page) sensor SR21 MP tray media-presence sensor SR22 Duplex re-pickup sensor (duplex models only) SR23 Cassette-media stack-surface sensor 1 SR24 Cassette-media stack-surface sensor 2 SR25 Cassette presence sensor SW4 Cassette media size switch Media sensor

38 Chapter 1 Theory of operation ENWW

Figure 1-31 Motors and solenoids for the pickup, feed, and delivery system

M2 M11

Duplex model only

SL2

Duplex flapper

Pickup arm

SL4

Lifter

M13

Table 1-13 Motors and solenoids for the pickup, feed, and delivery system

Abbreviation Component

M1 ITB motor M2 Fuser motor M7 Lifter motor M11 Duplex reverse motor (duplex models only) M13 Pickup motor CL1 Duplex re-pickup clutch (duplex models only) SL2 Duplex reverse solenoid (duplex models only) SL3 Multipurpose tray pickup solenoid SL4 Cassette pickup solenoid

CL1

SL3

ENWW Pickup, feed, and delivery system 39

The pickup, feed, and delivery system is divided into the following three blocks:

Pickup-and-feed block: From each pickup source to the fuser inlet

●

Fuser-and-delivery block: From the fuser to the delivery destination

●

Duplex block: From the duplex reverse uni t to dupl ex r e- pic kup uni t (for duplex models only)

●

Figure 1-32 Three main units of the pickup, feed, and delivery system

Fusing-and-delivery block

Duplex block

Pickup-and-feed block

40 Chapter 1 Theory of operation ENWW

Pickup-and-feed unit

The pickup-and-feed unit picks an individual sheet of paper from the multipurpose tray or the cassettes, carries it through the secondary-transfer unit, and feeds it into the fuser.

Figure 1-33 Pickup-and-feed uni t

Simplex media path Duplex media path

Pickup-and-feed block

Cassette pickup

The sequence of steps for the cassette-tray pickup operation is the following:

1. The product is turned on or the cassette is inserted.

2. The cassette lift-up operation raises the lifting plate so paper can be picked up.

3. The pickup motor rotates when a print command is received from the formatter.

4. T he cass ette pi ck up ro lle r, cassette feed roller, and casse tte s eparation roller rotate.

5. The cassette pickup solenoid turns on at a specified time.

6. T he cass ette pickup cam rotates.

ENWW Pickup, feed, and delivery system 41

7. As the pickup arm lowers, the cassette pickup roller touches the surface of the paper stack.

8. One sheet of paper feeds into the product. Figure 1-34 Cassette-pickup mechanism

DC controller

Cassette pickup cam

SL1

Cassette pickup solenoid

Cassette-presence detect ion

The product detects the size of the paper loaded in the cassette and the presence of the cassette by monitoring the cassette media size switch. The DC controller notifies the formatter when it determines the absence of the cassette.

Pickup motor

Cassette feed roller

Cassette pickup roller

Pickup arm

M13

Cassette pickup solenoid

Cassette separation roller

Cassette feed roller

Pickup arm

Cassette pickup roller

Cassette separation roller

Paper size Cassette media size switch

Top switch

Universal ON ON ON A5 OFF OFF ON B5 OFF ON ON Executive ON OFF ON Letter OFF ON OFF A4 ON OFF OFF Legal ON ON OFF Cassette absence OFF OFF OFF

Center switch Bottom switch

42 Chapter 1 Theory of operation ENWW

Cassette lift operation an d cassette paper-presence d et ectio n

The product keeps the paper stack surface at the correct pickup position. The cassette lift-up operation is performed under the following c ond iti ons :

The product is turned on

●

The cassette is in serted

●

The paper stack surface in the casse tte lo wer s

●

Figure 1-35 Cassette lift mechanism

DC controller

SR23

Cassette media

Lifter motor

presence sensor

SR1

Cassette media stack surface sensor 1 Cassette media stack surface sensor 2

SR24

Lifting plate

The operational sequence of the cas s ette lift-up is as fo llows:

1. The lifter motor rotates and the lifter moves up.

2. When the cassette-media stack surface sensor 2 detects the stack surface of media, the lifter motor

stops.

3. The lifter motor rotates again to lift the lifter when the cassette-media stack surface sensor 1 detects

the stack surface and then lower s durin g pr inti ng.

When a cassette-media stack surface sensors does not detect the stack surface within a specified time period after the lifter motor starts rotating, the DC controller determines a lifter motor failure and notifies the formatter

Cassette multiple-feed preven tion

In the cassette, a separation roller prevents multiple sheets of paper from entering the paper path. The cassette pickup roller dr iv es the separation roller through a sheet of pap er .

The rotation of the cassette feed roller through the sheet drives the cassette separation roller. Because it is equipped with a torque limiter, only one sheet is fed into the product.

Cassette media stack surface sensor lever

Cassette media presence sensor lever

Lifter

ENWW Pickup, feed, and delivery system 43

The low friction force between the sheets weakens the driving force from the cassette feed roller. Therefore, the separation roller is driven by its own driving force and holds back any multiple-fed sheets from the cassette.

Figure 1-36 Multiple-fe ed pr ev ent ion

Cassette feed roller

Cassette pickup roller

Cassette separation roller follows the cassette feed roller

Driving force from

Print-media

Cassette separation roller

Normal-feed

the pickup motor

Multiple-feed

Multipurpose tray pickup

The product picks up one sheet of paper from the MP tray . The sequence of steps for the multipurpose tray pickup operation as follows:

1. The pickup motor reverses when a print command is received from the formatter .

2. When the DC controller turns on the MP tray pickup solenoid, the MP tray pickup roller rotates and

the lifting plate lifts.

3. As the lifti ng pla te ri se s, the pap er is picke d up.

4. The multipurpose tray separation pad removes any multiple-fed sheets, and one sheet is fed into

the product.

44 Chapter 1 Theory of operation ENWW

The MP-tray media-presence sensor (SR8) detects whether paper is present in the MP tray.

Figure 1-37 Multipurpose tray pickup mechanism

DC controller

Paper feed

After the pickup operation, the paper feeds through the product and into the fuser.

Pickup motor

MP tray pickup solenoid

MP tray pickup roller

MP tray separation pad

M13

SL2

MP tray media presence sensor SR8

Lifting plate

1. The paper picked up from the cassette is fed to the registration unit as the pickup motor rotates.

The paper picked up from the multipurpose tray is fed to the registration unit as the pickup motor rotates. The duplex model has the duplex feed clutch. The driving force of the pickup motor is transmitted to the duplex re-pickup ro ll er by turning on the clutch.

2. T he re gis tr ati on shutter corrects the sk ew- fee d.

3. When the TOP sensor detects the leading edge of paper, the DC controller stops the paper so that

the media sensor detects the type of paper.

4. The DC controller controls the rotational speed of the pickup motor to align the paper with the

leading edge of the toner image on the ITB.

5. The ITB motor rotates the ITB.

6. The toner image on the ITB is transferred onto the paper, and the paper is fed to the fuser.

ENWW Pickup, feed, and delivery system 45

The DC controller notifies the formatter of a paper size mismatch error when the paper length detected by the TOP sensor does not match the paper size specified by the formatter.

Figure 1-38 Paper-feed me ch ani sm

DC controller

ITB

Pickup motor

M13

TO P sensor

SR20

Duplex re-pickup clutch

CL1

Media sensor

Registration shutter

Duplex re-pickup roller

Registration front feed roller

ITB motor

46 Chapter 1 Theory of operation ENWW

Skew-feed preventio n

The product can straighten the pap er wi thou t slow ing the feed oper ati on.

1. The leading edge of paper strikes the registration shutter, and the leading edge is aligned with the

shutter.

2. As the feed rollers keep pushing the paper, the paper warps.

3. When the force is great enough, the registration shutter opens, and the paper passes through and

straightens

Figure 1-39 Skew-feed prevention

Registration shutter

Paper

Paper detection

The product detects the type of paper by monitoring the media sensor. The media sensor detects the glossiness of paper by the reflected light and the thickness of paper by transmitted light. The DC controller identifies the type of paper (for example, plain paper, light paper, heavy paper, glossy paper,

ENWW Pickup, feed, and delivery system 47

glossy film, or overhead transparency) and switches to the correct print mode. The DC controller determines a media mismatch error and notifies the formatter under the following condition:

Simplex printing

The specified print mode is overhead transparency (OHT), but the media sensor detects another

●

paper type. The specified print mode is not auto or OHT, but the media sensor detects OHT.

●

Duplex printing

The media sensor detects O HT.

●

The DC controller flashes the med ia se nso r dur in g the ini tial rotation period under the foll owi ng conditions:

The product is turned on

●

The product exits Sleep mode

●

When the light intensity is not a specified value, the DC controller determines a media-sensor failure and notifies the formatter.

Feed speed control

For the best print quality, the product adj usts the feed speed depending on the paper ty pe.

Table 1-14 Print mode and feed speed

Print mode Feed speed Media sensor detection

Normal 1/1 Yes Heavy media 1 3/4 Heavy media 2 1/2 Yes Heavy media 3 1/3 Yes Light media 1 1/1 Yes Glossy media 1 1/3 Yes Glossy media 2 1/3 Yes Glossy media 3 1/4 Yes Glossy film 1/4 Yes Envelope 1/2 No OHT 1/4 Yes Label 1/2 No Designated media 1 1/2 No

Fusing and delivery unit

The fusing and delivery unit fuses the toner onto the paper and delivers the printed page into the output bin. The following controls ens ure optimum print quality:

48 Chapter 1 Theory of operation ENWW

The face-down tray media full sensor on the output bin detects whether the tray is full of printed pages. The DC controller notifies the formatter when the sensor is on for a specified time.

Figure 1-40 Fuser and delivery unit

Simplex media path Duplex media path

Fusing-and-delivery block

SR6

Face-down tray media full sensor

Loop control

The loop control stabilizes the paper feed operation before the paper enters the fuser. If the pressure roller rotate slower than the secondary transfer roller, the paper loop increases and an image defect or paper crease occurs. If the pressure roller rotate faster than the secondary transfer roller, the paper loop decreases and a verti ca l sc ann ing magnification failur e occ ur s be ca use t he pr es sure r oll er pulls the paper.

To prevent these problems, loop sensor 1 and loop sensor 2 detect the paper loop before the paper enters the fuser. The DC controller adjusts the rotational speed of the fuser motor according to the output signals from the loop sensors and maintains the paper loop. Loop sensor 1 is for light media, and loop

ENWW Pickup, feed, and delivery system 49

sensor 2 is for heavy media. The DC controller slows the fuser motor when the sensor is off and speeds up the sensor when the sensor is on.

Figure 1-41 Loop-contr ol me ch ani sm

Pressure roller

Sensor flag

Pressure roller

ITB

Secondary transfer rollerr

The pressure roller rotates faster than the secondary transfer roller

SR15: Loop sensor 2

SR14: Loop sensor 1

Loop sensor 1,2

Sensor flag

For heavy media

For light media

Sensor flag

The pressure roller rotates slower than the secondary transfer roller

Loop sensor: OFF

Loop sensor: ON

50 Chapter 1 Theory of operation ENWW

Pressure-roller pressurization control

To prevent excessive wear on the pressure roller and help with jam-clearing procedures, the pressure roller pressurizes only duri ng pr int ing and stan dby . Th e DC co ntr oll er rev er ses the fuse r motor. The fuser motor rotates the fuser pressure-release cam.

Figure 1-42 Pressure-roller pre ss uriz ati on c ontrol

DC controller

Fuser motor

SR7 SR7

Fuser pressure release cam

Pressure roller

Fuser sleeve

Pressurized Depressurized

The pressure rolle r de pr ess ur iz es unde r the following conditions:

The product is turned off

●

Any failure occurs

●

During powersave mode

●

When a paper jam is detected

●

If the DC controller does not sense the fuser pressure-release sensor for a specified period after it reverses the fuser motor, it notifie s the for ma tter that a fus er press ure- re lea se mech ani sm f ail ure has occurred.

ENWW Pickup, feed, and delivery system 51

Duplexing unit (HP Color LaserJet CP4525dn, HP Color LaserJet CP4025dn, and HP Color LaserJet CP4525xh only)

For supported models, the duplexing unit reverses the paper and feeds it through the paper path to print the second side.

Figure 1-43 Duplexing unit

Simplex media path Duplex media path

Duplex block

Duplexing reverse and feed control

The duplex reverse control reverses the paper after the first side is printed and feeds it to the duplex repickup position to print the second side of the page.

1. At a specified time after the first side of a page is printed, the duplex reverse motor rotates, and

the duplex reverse solenoid is turned on.

2. The duplex flapper moves, and the paper is fed to the duplex reverse unit.

3. After a specified period of time, the duplex reverse motor is reversed, and the paper is fed to the

duplex feed unit.

4. The duplex reverse motor and the pickup motor move the paper to the duplex re-pickup position.

52 Chapter 1 Theory of operation ENWW

5. The duplex reverse motor and the duplex feed clutch stop, and the paper feed operation pauses.

6. After a specified period of time, the dup lex rever se motor rota tes, and the dup lex feed clutc h is

turned on. The paper is then picked up again.

Figure 1-44 Duplex reverse and feed control

Duplex reverse unit

M11

Duplex flapper

Duplex reverse solenoid

Duplex re-pickup clutch

Duplex re-pickup position

SL2

Duplex feed unit

Duplex reverse motor

Pickup motor

CL1

M13

Simplex media path Duplex media path

Duplex print operation

The product has the following two duplex-media-feed modes depending on the paper sizes:

One-sheet mode: Prints one sheet that is printed on two sides in one duplex print operation

●

Two-sheet mode: Prints two sheets that are printed on two-sides in one duplex print operation

●

Table 1-15 Paper sizes

Paper size Duplex media feed mode A4 One-sheet operation Letter B5 Executive Legal One-sheet operation

ENWW Pickup, feed, and delivery system 53

Two-sheet operation

The formatter specifies the duplex-media-feed mode for each two-sided print job. Duplex printable media size (A4, Letter, B5, Legal and Executive) and designated print mode (Auto, Normal, Heavy media 1, Heavy media 2 (120 g/m2 or lighter ), Glossy med ia 1, Glos sy medi a 2, Gloss y med ia 3, Glossy fil m, Designated media 1, and Designated media 2) must be specified.

54 Chapter 1 Theory of operation ENWW

Jam detection

The product uses the following sensors to detect the paper as it moves through the paper path and to report to the DC controller if the paper has jammed.

Fuser delivery sens or (S R5)

●

TOP (top of page) sensor (SR20)

●

Loop sensor 1 (SR14)

●

Loop sensor 2 (SR15)

●

Duplex re-pickup sensor (SR22)

●

Figure 1-45 Jam detection sensors

Duplex model only Simplex media path Duplex media path

SR5

SR14

SR15

SR22

SR20

The product determines that a jam has occurred if one of these sensors detects paper at an inappropriate time. The DC controller stops the print operation and notifies the formatter.

ENWW Jam detection 55

Table 1-16 Jams that the product detects

Jam Description

Pickup delay jam The TOP sensor does not detect the leading edge of the paper within a

Pickup stationary jam The TOP sensor does not detect the trailing edge of the paper within a

Fuser delivery delay jam

Fuser del i ve ry stationary jam

Wrapping jam After detecting the leading edge of the paper, the fuser delivery sensor

Residual paper jam One of the following sensors detects paper presence during the initialization

specified time (including two retries) after the pickup operation from the cassette, multipurpose tray, or optional paper feeder starts.

specified time from when it detects the leading edge. The fuser delivery sensor does not detect the leading edge of the paper

within a specified period after the TOP sensor detects the leading edge. The fuser delivery sensor does not detect the trailing edge of the paper

within a specified period after it detects the leading edge.

detects the absence of paper, and it has not yet detected the trailing edge.

sequence:

Fuser delivery sensor

●

Loop sensor 1

●

Loop sensor 2

●

One of the following sensors detects paper presence during the an automatic delivery operation:

Fuser delivery sensor

●

TOP sensor

●

Loop sensor 1

●

Loop sensor 2

●

Duplex re-pickup sensor

●

Door open jam A door is open while paper is moving through the product. Duplexing re-pickup

jam 1

Duplexing re-pickup jam 2

The duplex re-pickup sensor does not detect the leading edge of the paper within a specified period after the media reverse operation starts in the duplex reverse unit.

The TOP sensor does not detect the leading edge of the paper within a specified period after the paper is re-picked.

Automatic delivery: The produ ct automatically clears pape r if the TOP sensor detects resid ual paper during initiali za tio n .

56 Chapter 1 Theory of operation ENWW

Optional paper feeder

The 1 x 500-sheet paper feeder is optionally installed at bottom of the product. The paper feeder picks up the print media and feeds it to the product. There are two types of paper feeders: 1 x 500-sheet paper feeder and 3 x 500-sheet paper feeder. The operational sequence of the paper feeders is controlled by the paper feeder contr ol ler.

Figure 1-46 1 x 500 optional paper feeder

PD pickup roller

PD feed roller

PD separation roller

ENWW Optional paper feeder 57

Figure 1-47 3 x 500-sheet optional paper feeder

PD feed roller

PD pickup roller

PD separation roller

Figure 1-48 Signals for the paper feeder

Paper deck

Motor

+3.3V

Solenoid

Photointerrupter

Switch

DC controller

+24V

Paper deck

controller

The input trays contain several motors, solenoids, sensors, and switches, as described in the following table.

58 Chapter 1 Theory of operation ENWW

Table 1-17 Electrical components for the paper feeder

Component type

Motors M1 PD lifter motor 1

Solenoids SL1 PD pickup solenoid 1

Sensors SR1 Tray 3 paper surface sensor 1

Abbreviation Component name

M2 PD pickup motor M3 PD lifter motor 2 (3 x 500-sheet paper feeder only) M4 PD lifter motor 3 (3 x 500-sheet paper feeder only)

SL2 PD pickup solenoid 2 (3 x 500-sheet paper feeder only) SL3 PD pickup solenoid 3 (3 x 500-sheet paper feeder only)

SR2 Tray 3 paper surface sen sor 2 SR3 Tray 3 paper present presence sens or SR4 Tray 3 feed sensor SR5 Tray 4 paper surface sensor 1 (3 x 500-sheet paper feeder only) SR6 Tray 4 paper present sensor (3 x 500-sheet paper feeder only) SR7 Tray 4 feed sensor (3 x 500-sheet paper feeder only) SR8 Tray 4 paper surface sensor 2 (3 x 500-sheet paper feeder only)

Switches SW1 PD right door switch

Motor control

The 1 x 500-sheet paper feeder has two motors, and the 3 x 500-sheet paper feeder has four motors for feeding paper.

Component Drives Failure detection

PD lifter motor 1 M1 Lifter of the upper cassette No PD lifter motor 2 (3 x 500-sheet paper

feeder only)

SR9 Tray 5 paper surface sensor 1 (3 x 500-sheet paper feeder only) SR10 Tray 5 feed sensor (3 x 500-sheet paper feeder only) SR11 Tray 5 paper present sensor (3 x 500-sheet paper feeder only) SR12 Tray 5 paper surface sensor 2 (3 x 500-sheet paper feeder only)

SW2 PD media size switch 1 (3 x 500-sheet paper feeder only) SW3 PD media size switch 2 (3 x 500-sheet paper feeder only) SW4 PD media size switch 3 (3 x 500-sheet paper feeder only)

M3 Lifter of the middle cassette No

ENWW Optional paper feeder 59

Component Drives Failure d etecti o n

PD lifter motor 3 (3 x 500-sheet paper feeder only)

PD pickup motor M2 PD pickup roller, PD feed roller, and PD

M4 Lifter of the lower cassette No

Paper-feeder pickup and feed operation

The paper feeder picks up one sheet from the paper-feeder cassette and feeds it to the product.

Figure 1-49 Paper-feeder pic k up and fe ed ope ration

SW2

separation roller

Pickup arm

SR3

SR4

SR2

SR1

SL1

Table 1-18 Pickup feed components (1 x 500-sheet paper feeder)

Component

M1 PD lifter motor 1 M2 PD pickup motor SL1 PD pickup solenoid 1 SR1 Tray 3 paper surface sensor 1 SR2 Tray 3 paper surface sensor 2

60 Chapter 1 Theory of operation ENWW

Table 1-18 Pickup feed components (1 x 500-sheet paper feeder) (continued)

Component

SR3 Tray 3 paper presence sensor SR4 Tray 3 paper present sensor SW2 Tray 3 paper size switches

SW2

SW3

SW4

Pickup arm

SR11

SR3

SR6

SR2

SR8

SR9

SR1

SR5

SR12

SR4

SL1

SR7

SW1

SL2

SR10

SL3

Components M1 PD lifter motor 1 M2 PD pickup motor M3 PD lifter motor 2 (3 x 500-sheet paper feeder only) M4 PD lifter motor 3 (3 x 500-sheet paper feeder only) SL1 PD pickup solenoid 1 SL2 PD pickup solenoid 2 SL3 PD pickup solenoid 3 SR1 Tray 3 paper surface sensor 1 SR2 Tray 3 paper surface sensor 2 SR3 Tray 3 paper presence sensor SR4 Tray 3 paper presence sensor

ENWW Optional paper feeder 61

SR5 Tray 4 paper surface sensor 1 (3 x 500-sheet paper feeder only) SR6 Tray 4 paper surface sensor 2 (3 x 500-sheet paper feeder only) SR7 Tray 4 feed sensor (3 x 500-sheet paper feeder only) SR8 Tray 4 media-stack-surface sensor (3 x 500-sheet paper feeder only) SR9 Tray 5 paper surface sensor 1 (3 x 500-sheet paper feeder only) SR10 Tray 5 feed sensor (3 x 500-sheet paper feeder only) SR11 Tray 5 paper present sensor (3 x 500-sheet paper feeder only) SR12 Tray 5 media-stack-surface sensor (3 x 500-sheet paper feeder only) SW1 Tray 3, 4, and 5 right door switch SW2 Tray 3 paper size switches (3 x 500-sheet paper feeder only) SW3 Tray 4 paper size switches (3 x 500-sheet paper feeder only) SW4 Tray 5 paper size switches (3 x 500-sheet paper feeder only)

Paper-size detection and cassette-presence detection

The paper feeder detects the size of paper loaded in the paper feeder and the presence of the cassette using the PD media size switch.

Paper size Paper-feeder cassette media-size switch setti ngs

Top switch

Universal ON ON ON A5 OFF OFF ON B5 OFF ON ON Executive ON OFF ON Letter OFF ON OFF A4 ON OFF OFF Legal ON ON OFF No cassette OFF OFF OFF

Center switch Bottom switch

62 Chapter 1 Theory of operation ENWW

Paper-feeder cassette lift operation

The paper feeder keeps the paper stack surface at the correct pickup position. The cassette lift operation occurs under the following cond iti ons :

The product is turned on.

●

The cassette is in serted.

●

The paper stack surface of the cassette lowers.

●

The sequence occurs as follows:

1. The PD lifter motor rotates and the lifter moves up.

2. When the tray media-stack-surface sensor detects the stack surface of the paper, the PD lifter

motor stops.

3. The PD lifter motor rotates again to lift the lifter when the PD cassette media-stack-surface sensor

detects the stack surface, and then lowe rs durin g pri nti ng.

If a tray media-stack-surface sensor does not detect a stack surface within a specified period after the PD lifter motor starts rotating, the paper feeder driver determines that the PD lifter motor has failed and through the DC controller notifies the formatter.

Figure 1-50 Paper-feeder cassette lift

PD cassette media stack surface sensor 1

SR1/SR5/SR12

PD cassette media stack surface sensor 2

SR2/SR8/SR9

PD cassette media presence sensor

SR3/SR6/SR11

PD cassette media stack surface sensor lever

Lifting plate

M1/M3/M4

PD lifter motor

Lifter

PD cassette media presence sensor lever

The paper-feeder driver notifies the formatter if either of the paper-feeder media-stack surface sensors fails to detect the stack surfac e with in a spe ci fie d peri od from when a lift-up operation star ts.

ENWW Optional paper feeder 63

Paper feeder jam detection

The 1 x 500-sheet paper feeder uses the tray 3 paper presence sensor (SR4) to detect the presence of paper and to check whether paper has ja mm ed.

Figure 1-51 Jam detection (1 x 500 -s heet paper feeder)

SR4

The 1 x 500-sheet paper feeder detects the following jam s:

1 x 500-sheet PD pickup delay jam: Tray 3 feed sensor does not detect the leading edge of paper

●

within a specified time (including two retries) after the pickup operation starts. 1 x 500-sheet PD pickup stationary jam: Tray 3 feed sensor does not detect the trailing edge of

●

paper within a specified time after the sensor detects the leading edge. 1 x 500-sheet PD residual paper jam: Tray 3 feed sensor detects the presence of paper for a

●

specified time during an automatic delivery operation.

The 3 x 500-sheet paper feeder uses the following sensors to detect the presence of paper and to check whether paper has jammed.

Tray 3 paper presence sensor (SR4 )

●

Tray 4 feed sensor (SR7)

●

Tray 5 feed sensor (SR10)

●

64 Chapter 1 Theory of operation ENWW

Figure 1-52 Jam detection (3 x 500-sheet paper feeder)

SR4

SR7

SR10

The 3 x 500-sheet paper feeder detec ts the fo llowing jams:

3 x 500-sheet PD pickup delay jam: One of the tray feed sensors does not detect the leading edge

●

of paper within a specified t ime (incl udi ng two retries) after the pickup oper ation starts. 3 x 500-sheet PD pickup delay jam 2: Tray 3 feed sensor does not detect the leading edge of paper

●

within a specified time (including two retries) after the pickup operation starts. 3 x 500-sheet PD pickup stationary jam 1: Tray 4 or 5 feed sensors do not detect the trailing edge

●

of paper within a specified time after the sensor detects the leading edge. 3 x 500-sheet PD pickup stationary jam 2: Tray 3 feed sensor does not detect the trailing edge of

●

paper within a specified time after the sensor detects the leading edge. 3 x 500-sheet PD residual paper jam: Tray 3, 4, or 5 feed sensors detect the presence of paper for

●

a specified time during an automa tic del iv er y ope ra tion. 3 x 500-sheet PD door open jam: The door is open during paper feed operation.

●

ENWW Optional paper feeder 65

66 Chapter 1 Theory of operation ENWW

2 Removal and replacement

Introduction

●

Removal and replacement st ra teg y

●

Electrostatic discharge

●

Required tools

●

Before performing service

●

After performing s er vi ce

●

Post-service t est

●

Parts removal o rd er

●

Customer self repair (CSR) components

●

External panels, cover s, and doo rs

●

Internal assemblies

●

Optional paper feeder assembl ies (1 x 500-s hee t and 3 x 50 0- she et)

●

ENWW 67

Introduction

This chapter describes the removal and replace men t of fiel d- replaceable units (FR Us) onl y. Replacing FRUs is generally the reverse of removal. Occasionally, notes and tips are included to provide

directions for diffic ult or critical replacement procedures. HP does not support repairing individual subassemblies or troubleshooting to the component level. Note the length, diameter, color, type, and location of each screw. Be sure to return each screw to its

original locatio n dur i ng r eassembly. Incorrectly routed or loose wire harnesses can interfere with other internal components and can become

damaged or broken. Frayed or pinched harness wires can be difficult to find. When replacing wire harnesses, always use the provided wire loops, lance point s, or wir e-har ne ss guides and retainers.

Removal and replacement strategy

WARNING! Turn the product off, wait 5 seconds, and then remove the power cord before attempting

to service the product. If this warning is not followed, severe injury can result, in addition to damage to the product. The power must be on for certain functional checks during troubleshooting. However, disconnect the power supp ly during parts removal.

Never operate or serv ic e the pr odu ct with the protective cove r r emo ved f rom the la ser /s ca nne r assembly. The reflected beam, although invisible, can damag e you r eyes .

The sheet-metal parts can have sharp edges. Be careful when handling sheet-metal parts.

CAUTION: Do not bend or fold the flat flexible cables (FFCs) during removal or installation. Also, do

not straight en pre-folds in the FFCs. You must fully seat all FFCs in their connectors. Failure to fully seat an FFC into a connector can cause a short circuit in a PCA.

NOTE: To install a self-tapping screw, first turn it countercloc kw is e to alig n it with the existing thread

pattern, and then carefully turn it clockwise to tighten . Do not overtighte n. If a se lf-tapp in g scre w-hole becomes stripped, repair the screw-hole or replace the affected assembly.

TIP: For clarity, some photos in this chapter show components removed that would not be removed

to service the product. If necessary, rem ov e the co mponents listed at the beginning of a pr oc edu re before proceeding to service the pro duct.

68 Chapter 2 Removal and replacement ENWW

HP CP4020, CP4520 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Theory of operation

Basic operation

Sequence of operation

Engine-control system

DC controller

Solenoids

Clutches

Switches

Sensors

Motors

Fans

High-voltage power supply

Low-voltage power supply

Overcurrent/overvoltage protection

Safety

Voltage detection

Sleep (powersave) mode

Low-voltage power supply failure

Fuser control

Fuser temperature control

Fuser sleeve temperature p rotection

Failure detection

Fuser unit identification

Fuser unit life detection

Laser/scanner system

Laser/scanner failure

Protective-glass cleaners

Image-formation system

Image-formation process

Step 1: Pre-exposure

Step 2: Primary charging

Step 3: Laser -beam exposure

Step 4: Develo pment

Step 5: Primary transfer

Step 6: Secondary transfer

Step 7: Separation

Step 8: Fusing

Step 9: ITB cleaning

Step 10: Drum cleaning

Print cartridge

Developing-roller engagement and disengagement

Intermediate transfer belt (ITB) unit

Primary-transfer-roller engagement and disengagement

ITB cleaning

Calibration

Color-misregistration control

Image-stabilization control

Pickup, feed, and delivery system

Pickup-and-feed unit

Cassette pickup

Cassette-presence detect ion

Cassette lift operation an d cassette paper-presence d et ectio n

Cassette multiple-feed preven tion

Multipurpose tray pickup

Paper feed

Skew-feed preventio n

Paper detection

Feed speed control

Fusing and delivery unit

Loop control

Pressure-roller pressurization control

Duplexing reverse and feed control

Duplex print operation

Jam detection

Optional paper feeder

Motor control

Paper-feeder pickup and feed operation

Paper-size detection and cassette-presence detection

Paper-feeder cassette lift operation

Paper feeder jam detection

2 Removal and replacement

Introduction

Removal and replacement strategy