HP m552, m553, m577 Troubleshooting Manual

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Troubleshooting Manual

Color LaserJet Enterprise M552 Color LaserJet Enterprise M553

www.hp.com/support/colorlj552 www.hp.com/support/colorlj553 www.hp.com/support/colorljM577MFP

For printer part removal and part number information, see the Repair Manual.

M553xM552dn

M553dn

M553n

M577dn

M577f

M577c

M577z

Color LaserJet Enterprise MFP M577

HP Color LaserJet Enterprise M553, HP Color LaserJet Enterprise M552, and HP Color LaserJet Enterprise MFP M577

Troubleshooting Manual

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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.

Edition 1, 11/2015

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

Conventions used in this guide

TIP: Helpful hints or shortcuts.

NOTE: Information that explains a concept or how to complete a task.

Reinstallation tip: Reinstallation helpful hints, shortcuts, or considerations.

IMPORTANT: Information that help the user to avoid potential printer error conditions.

CAUTION: Procedures that the user must follow to avoid losing data or damaging the printer.

WARNING! Procedures that the user must follow to avoid personal injury, catastrophic loss of data, or

extensive damage to the printer.

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iv Conventions used in this guide ENWW

For additional service and support information

HP service personnel, go to the Service Access Work Bench (SAW) at http://h41302.www4.hp.com/km/saw/

home.do.

Channel partners, go to HP Channel Services Network (CNS) at https://h30125.www3.hp.com/hpcsn.

At these locations, nd information on the following topics:

●

Install and congure

●

Printer specications

●

Up-to-date control panel message (CPMD) troubleshooting

●

Solutions for printer issues and emerging issues

●

Remove and replace part instructions and videos

●

Service advisories

●

Warranty and regulatory information

To access HP PartSurfer information from any mobile device, go to http://partsurfermobile.hp.com/ or scan the Quick Response (QR) code below.

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vi For additional service and support information ENWW

Table of contents

1 Theory of operation ....................................................................................................................................... 1

For additional service and support ........................................................................................................................ 2

Basic operation ...................................................................................................................................................... 3

Sequence of operation ........................................................................................................................ 5

Formatter-control system ..................................................................................................................................... 7

Sleep mode .......................................................................................................................................... 7

Printer job language (PJL) ................................................................................................................... 8

Printer management language (PML) ................................................................................................. 8

Control panel ....................................................................................................................................... 8

Easy-access USB port .......................................................................................................................... 9

Wireless ............................................................................................................................................... 9

Near eld communication (NFC) .......................................................................................................... 9

CPU ....................................................................................................................................................... 9

Input/output (I/O) ................................................................................................................................ 9

Memory ................................................................................................................................................ 9

Firmware ......................................................................................................................... 10

Nonvolatile random access memory (NVRAM) ............................................................... 10

Random access memory (RAM) ...................................................................................... 10

HP Memory Enhancement technology (MEt) .................................................................. 10

Engine-control system ........................................................................................................................................ 11

DC controller ...................................................................................................................................... 12

Motors ............................................................................................................................. 13

Fans ................................................................................................................................. 14

Solenoids ......................................................................................................................... 14

Clutches ........................................................................................................................... 14

Switches .......................................................................................................................... 14

Sensors ........................................................................................................................... 16

Low-voltage power supply ................................................................................................................ 18

Low-voltage power supply voltages description ........................................................... 19

Over-current/over-voltage protection ........................................................................... 19

Sleep mode operation ..................................................................................................... 19

Low-voltage power supply failure detection ................................................................. 20

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Low-voltage power supply functions ............................................................................. 20

High-voltage power supply ............................................................................................................... 20

High-voltage power supply circuits ................................................................................ 21

Fuser bias ........................................................................................................................ 22

Fuser control ..................................................................................................................................... 22

Fuser circuits ................................................................................................................... 22

Fuser control functions ................................................................................................... 24

Fuser temperature control ............................................................................................. 24

Fuser heater protection .................................................................................................. 26

Fuser unit life detection .................................................................................................. 26

Fuser identication ......................................................................................................... 26

Engine laser/scanner system .............................................................................................................................. 27

Laser/scanner failure detection ........................................................................................................ 28

Safety ................................................................................................................................................ 28

Image-formation process ................................................................................................................. 29

Step 1: Pre-exposure ...................................................................................................... 35

Step 2: Primary charging ................................................................................................ 35

Step 3: Laser-beam exposure ......................................................................................... 36

Step 4: Development ...................................................................................................... 36

Step 5: Primary transfer ................................................................................................. 37

Step 6: Secondary transfer ............................................................................................. 37

Step 7: Separation ........................................................................................................... 38

Step 8: Fusing .................................................................................................................. 38

Step 9: ITB cleaning ......................................................................................................... 39

Step 10: Drum cleaning ................................................................................................... 39

Toner cartridges ................................................................................................................................ 40

Design ............................................................................................................................. 40

Memory chip .................................................................................................................... 42

Toner seal ........................................................................................................................ 42

Toner level and cartridge life detection .......................................................................... 42

Developing unit engagement and disengagement control ........................................... 42

Cartridge Authentication Technology (CAT) ................................................................... 43

Authentication .............................................................................................. 44

Anti-theft ...................................................................................................... 44

Intermediate transfer belt (ITB) unit ................................................................................................. 45

Primary-transfer roller engagement and disengagement control ................................ 45

ITB unit detection ............................................................................................................ 47

ITB cleaning mechanism ................................................................................................. 48

Secondary transfer roller functions ............................................................................... 48

Calibration ....................................................................................................................... 49

Pickup, feed, and delivery system ....................................................................................................................... 50

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Photo sensors and switches ............................................................................................................. 51

Motors, clutches, and solenoids ........................................................................................................ 53

Tray 1 (multipurpose)/Tray 2 (base printer) ..................................................................................... 54

Tray 1 paper pickup and feed ......................................................................................... 54

Tray 2 paper presence detection .................................................................................... 55

Tray 2 lift operation ........................................................................................................ 55

Tray 2 paper pickup ......................................................................................................... 56

Tray 2 multiple-feed prevention ..................................................................................... 56

Tray 2 presence detection .............................................................................................. 57

Tray 2 skew feed prevention ........................................................................................... 57

Tray 2 media type detection ........................................................................................... 58

Feed speed control .......................................................................................................... 59

Duplexing unit (M552dn, M553dn, M553x, and M577 only) ............................................................ 60

Duplexing reverse and duplex feed control ................................................................... 60

Jam detection/prevention ................................................................................................................. 60

Fuser wrapping jam detection ........................................................................................ 62

Loop control .................................................................................................. 62

Pressure roller pressurization and depressurization control ...................... 63

Input accessories ................................................................................................................................................. 65

Trays 3-5 ........................................................................................................................................... 65

Trays 3-5 driver PCA ....................................................................................................... 65

Trays 3-5 motor control .................................................................................................. 66

Trays 3-5 electrical components .................................................................................... 66

Trays 3-5 paper pickup ................................................................................................... 67

Trays 3-5 multiple feed prevention ................................................................................ 67

Trays 3-5 tray presence detection .................................................................................. 67

Trays 3-5 tray lift operation ........................................................................................... 68

Trays 3-5 jam detection .................................................................................................. 69

Scanning and image capture system (M577) ...................................................................................................... 70

Document feeder system (M577) ........................................................................................................................ 71

Document feed system ..................................................................................................................... 71

Sensors in the document feeder ....................................................................................................... 71

Document feeder paper path ............................................................................................................ 72

Document feeder simplex operation ................................................................................................ 73

Document feeder e-duplex operation .............................................................................................. 74

Deskew operation .............................................................................................................................. 74

Document feeder hinges ................................................................................................................... 75

2 Solve problems ............................................................................................................................................ 77

For additional service and support ..................................................................................................................... 78

Solve problems checklist ..................................................................................................................................... 79

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Solve problems checklist ................................................................................................................... 79

Print the conguration page ............................................................................................................. 84

Print menu map ................................................................................................................................. 84

Print current settings pages ............................................................................................................. 85

Print event log ................................................................................................................................... 86

Pre-boot menu options ..................................................................................................................... 88

Remote Admin ................................................................................................................. 98

Required software and network connection ................................................ 98

Connect a remote connection .................................................................... 100

Disconnect a remote connection ................................................................ 104

Troubleshooting process ................................................................................................................................... 107

Determine the problem source ....................................................................................................... 107

Pre-troubleshooting checklist ...................................................................................... 107

Troubleshooting owchart ........................................................................................... 108

Power subsystem ............................................................................................................................ 109

Power-on checks ........................................................................................................... 109

Power-on troubleshooting overview ......................................................... 109

Control panel checks ....................................................................................................................... 113

Control-panel diagnostics ............................................................................................ 113

Touchscreen diagnostic mode (M553x and M577) .................................... 113

Control-panel system diagnostics (M553x and M577) .............................. 118

Control panel diagnostic owcharts (M553x and M577) ............................................. 133

Touchscreen black, white, or dim (no image) ............................................ 134

Touchscreen is slow to respond or requires multiple presses to

respond ....................................................................................................... 135

Touchscreen has an unresponsive zone .................................................... 136

No control panel sound .............................................................................. 137

Home button is unresponsive .................................................................... 138

Hardware integration pocket (HIP) is not functioning (control panel

functional) .................................................................................................. 139

Tools for troubleshooting .................................................................................................................................. 140

Individual component diagnostics .................................................................................................. 140

Tools for troubleshooting: LED diagnostics ................................................................. 140

Understand lights on the formatter ........................................................... 140

Tools for troubleshooting: Engine diagnostics ............................................................ 143

Engine test button ...................................................................................... 143

Defeating interlocks ................................................................................... 145

Disable cartridge check .............................................................................. 147

Tools for troubleshooting: Paper path and sensor diagnostic tests ........................... 148

Paper path test ........................................................................................... 148

Paper path sensors test ............................................................................. 149

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Manual sensor tests ................................................................................... 151

Tray/bin manual sensor test ...................................................................... 153

Tools for troubleshooting: Print/stop test ................................................................... 154

Tools for troubleshooting: Component tests ............................................................... 156

Individual component diagnostics (special-mode test) ............................ 156

Tools for troubleshooting: Scanner tests (M577 only) ................................................ 158

Scanner tests .............................................................................................. 158

Diagrams ......................................................................................................................................... 160

Diagrams: Block diagrams ............................................................................................ 161

Sensors and switches ................................................................................. 161

Cross section diagrams .............................................................................. 163

Diagrams: Printed circuit assembly (PCA) connector locations ................................... 164

DC controller PCA ........................................................................................ 165

Formatter PCA (M552 and M553) ............................................................... 167

Formatter PCA (M577) ................................................................................ 168

1x550-sheet paper feeder PCA .................................................................. 169

Scanner control board PCA ......................................................................... 170

Diagrams: External plug and port locations ................................................................. 171

Diagrams: Locations of major assemblies ................................................................... 172

Main assemblies (printer base) .................................................................. 172

Printed circuit assembly (PCA) locations ................................................... 175

Diagrams: General timing chart ................................................................................... 176

Diagrams: General circuit diagrams ............................................................................. 177

Internal test and information pages ............................................................................................... 180

Print a conguration page ............................................................................................ 180

HP embedded Jetdirect page ..................................................................... 182

Finding important information on the conguration pages ..................... 183

Print a cleaning page .................................................................................................... 184

Enable and congure auto cleaning ........................................................... 184

Control-panel menus ...................................................................................................................... 185

Administration menu .................................................................................................... 185

Reports menu ............................................................................................. 185

General Settings menu ............................................................................... 187

Copy Settings menu (M577 only) ............................................................... 201

Scan/Digital Send Settings menu (M577 only) .......................................... 209

Fax Settings menu (M577 only) ................................................................. 219

General Print Settings menu ...................................................................... 232

Default Print Options menu ....................................................................... 235

Display Settings menu ............................................................................... 237

Manage Supplies menu .............................................................................. 239

Manage Trays menu ................................................................................... 244

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Network Settings menu ............................................................................. 246

Troubleshooting menu ............................................................................... 257

Device Maintenance menu ............................................................................................ 260

Backup/Restore menu ................................................................................ 260

Calibration/Cleaning menu (M577 only) .................................................... 260

USB Firmware Upgrade menu .................................................................... 263

HP FutureSmart Level menu ...................................................................... 263

Service menu .............................................................................................. 263

Control panel message document (CPMD) ..................................................................................... 264

Control-panel message types ...................................................................................... 264

Control-panel messages and event log entries ........................................................... 264

10.XX.YZ Error Messages ........................................................................... 264

11.XX.YZ Error Messages ........................................................................... 273

13.XX.YZ Error Messages ........................................................................... 273

20.XX.YZ Error Messages ........................................................................... 294

30.XX.YZ Error Messages ........................................................................... 295

31.XX.YZ Error Messages ........................................................................... 302

32.XX.YX and 33.XX.YZ Error Messages .................................................... 309

40.XX.YZ Error Messages ........................................................................... 317

41.XX.YZ Error Messages ........................................................................... 318

42.XX.YZ Error Messages ........................................................................... 326

44.XX.XX Error Messages ........................................................................... 326

47.XX.XX Error Messages ........................................................................... 328

48.XX.YY Error Messages ........................................................................... 331

49.XX.YY Error Messages ........................................................................... 331

50.WX.YZ Error Messages .......................................................................... 332

51.XX.YZ, 52.XX.YZ Error Messages .......................................................... 338

54.XX.YZ Error Messages ........................................................................... 338

55.XX.YZ, 56.XX.YZ Error Messages .......................................................... 340

57.XX.YZ Error Messages ........................................................................... 342

58.XX.YZ Error Messages ........................................................................... 343

59.XX.YZ Error Messages ........................................................................... 345

60.00.0Y, 62.00.00 Error Messages ........................................................... 348

70.XX.YY Error Messages ........................................................................... 348

80.WX.YZ, 81.WX.YZ, 82.WX.YZ Error Messages ....................................... 349

90.XX.YY error messages ........................................................................... 350

98.0X.0Y Error Messages ........................................................................... 351

99.XX.YY Error Messages ........................................................................... 352

Alpha Error Messages ................................................................................. 359

Tools for troubleshooting: Event log messages .......................................................... 389

Print or view an event log ........................................................................... 390

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Clear the event log ..................................................................................... 391

Solve image-quality problems .......................................................................................................................... 392

Improve print quality ...................................................................................................................... 392

Color band test .............................................................................................................. 392

Repetitive image defect ruler ....................................................................................... 393

Use a ruler to measure between repetitive defects .................................. 394

Print-quality troubleshooting pages ............................................................................ 397

Print-quality assessment page .................................................................................... 401

Print from a dierent software program ..................................................................... 402

Check the paper-type setting for the print job ............................................................ 403

Check toner-cartridge status ....................................................................................... 403

Clean the printer ........................................................................................................... 404

Print a cleaning page .................................................................................. 404

Visually inspect the toner cartridge or cartridges ....................................................... 404

Check paper and the printing environment ................................................................. 405

Calibrate the printer ...................................................................................................... 405

Use manual print modes ............................................................................................... 406

Image defects table ...................................................................................................... 409

Clean the printer ................................................................................................................................................ 417

Clean the paper path ....................................................................................................................... 417

Print a cleaning page ....................................................................................................................... 417

Clean the Tray 1 rollers ................................................................................................................... 418

Step 1: Remove the Tray 1 pickup roller ....................................................................... 418

Step 2: Remove the Tray 1 separation roller ................................................................ 420

Step 3: Clean the Tray 1 rollers ..................................................................................... 422

Step 4: Install the Tray 1 separation roller ................................................................... 423

Step 5: Install the Tray 1 pickup roller .......................................................................... 426

Clean the Tray 2-X rollers ................................................................................................................ 429

Step 1: Remove the Tray 2-X paper pickup roller assembly ........................................ 429

Step 2: Remove the Tray 2-X separation roller ............................................................ 432

Step 3: Clean the Tray 2-X rollers ................................................................................. 434

Step 4: Install the Tray 2-X separation roller ............................................................... 434

Step 5: Install the Tray 2-X paper pickup roller assembly ........................................... 436

Check the scanner glass for dirt and smudges (M577 only) .......................................................... 439

Clean the pickup rollers and separation pad in the document feeder (M577 only) ....................... 442

Solve paper handling problems ........................................................................................................................ 444

Printer feeds incorrect page size .................................................................................................... 444

Printer pulls from incorrect tray ..................................................................................................... 444

Printer will not duplex or duplexes incorrectly ............................................................................... 444

Paper does not feed from Tray 2-X ................................................................................................. 445

Output is curled or wrinkled ............................................................................................................ 445

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Printer does not pick up paper or misfeeds .................................................................................... 446

The printer does not pick up paper .............................................................................. 446

The printer picks up multiple sheets of paper ............................................................. 447

Paper does not feed automatically .............................................................................. 447

Clear paper jams .............................................................................................................................. 447

Paper path jam sensor locations .................................................................................. 448

Auto-navigation for clearing jams ................................................................................ 449

Experiencing frequent or recurring paper jams? ......................................................... 449

Clear paper jams in the document feeder .................................................................... 451

Clear paper jams in Tray 1 ............................................................................................ 454

Clear paper jams in Tray 2 ............................................................................................ 456

Clear paper jams in the optional 550-sheet trays ....................................................... 460

Clear paper jams in the right door and the fuser area ................................................. 465

Clear paper jams in the output bin ............................................................................... 470

Change jam recovery .................................................................................................... 471

Solve performance problems ............................................................................................................................ 472

Factors aecting print performance ............................................................................................... 472

Print speeds ..................................................................................................................................... 473

The printer does not print or it prints slowly .................................................................................. 473

The printer prints slowly ................................................................................................................. 474

Solve connectivity problems ............................................................................................................................. 475

Solve USB connection problems ..................................................................................................... 475

Solve wired network problems ....................................................................................................... 475

Poor physical connection .............................................................................................. 475

The computer is using the incorrect IP address for the product .................................. 475

The computer is unable to communicate with the product ......................................... 476

The product is using incorrect link and duplex settings for the network .................... 476

New software programs might be causing compatibility problems ........................... 476

The computer or workstation might be set up incorrectly .......................................... 476

The product is disabled, or other network settings are incorrect ............................... 476

Service mode functions ..................................................................................................................................... 477

Service menu ................................................................................................................................... 477

Printer resets ................................................................................................................................... 479

Restore factory-set defaults ........................................................................................ 479

Restore the service ID ................................................................................................... 479

Printer cold reset .......................................................................................................... 480

Format Disk and Partial Clean functions ........................................................................................ 482

Active and repository rmware locations .................................................................... 482

Partial Clean .................................................................................................................. 482

Execute a Partial Clean ............................................................................... 483

Format Disk ................................................................................................................... 483

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Execute a Format Disk ................................................................................ 484

Firmware upgrades ............................................................................................................................................ 486

Determine the installed revision of rmware ................................................................................. 487

Perform a rmware upgrade .......................................................................................................... 488

HP Embedded Web Server ............................................................................................ 488

USB ash drive (Pre-boot menu) .................................................................................. 489

USB ash drive (control-panel menu) .......................................................................... 491

Solve email problems ........................................................................................................................................ 492

Cannot connect to the email server ................................................................................................ 492

Validate the SMTP gateway (Windows) .......................................................................................... 492

Validate the LDAP gateway (Windows) ........................................................................................... 492

Appendix A Printer specications .................................................................................................................. 493

Printer dimensions ............................................................................................................................................ 494

Printer space requirements ............................................................................................................................... 499

Power consumption, electrical specications, and acoustic emissions ........................................................... 499

Operating-environment range .......................................................................................................................... 499

Certicates of Volatility ..................................................................................................................................... 500

Index ........................................................................................................................................................... 505

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List of tables

Table 1-1 Sequence of operation .......................................................................................................................................... 5

Table 1-2 Motors ................................................................................................................................................................. 13

Table 1-3 Fans ..................................................................................................................................................................... 14

Table 1-4 Solenoids ............................................................................................................................................................ 14

Table 1-5 Clutches .............................................................................................................................................................. 14

Table 1-6 Switches .............................................................................................................................................................. 14

Table 1-7 Sensors ............................................................................................................................................................... 16

Table 1-8 Converted DC voltages ....................................................................................................................................... 19

Table 1-9 Low-voltage power supply functions ................................................................................................................. 20

Table 1-10 High-voltage power supply circuits ................................................................................................................. 21

Table 1-11 Fuser components ............................................................................................................................................ 23

Table 1-12 Low-voltage power supply functions ............................................................................................................... 24

Table 1-13 Motors ............................................................................................................................................................... 31

Table 1-14 Sensors ............................................................................................................................................................. 32

Table 1-15 Image formation process ................................................................................................................................. 33

Table 1-16 Primary-transfer roller engagement states .................................................................................................... 45

Table 1-17 Secondary transfer roller functions ................................................................................................................. 48

Table 1-18 Calibration functions ........................................................................................................................................ 49

Table 1-19 Photo sensors and switches ............................................................................................................................. 51

Table 1-20 Motors, clutches, and solenoids ....................................................................................................................... 53

Table 1-21 Print mode and feed speed .............................................................................................................................. 59

Table 1-22 Jams that the printer detects ........................................................................................................................... 61

Table 1-23 Trays 3-5 motor control ................................................................................................................................... 66

Table 1-24 Tray 3-5 electrical components ....................................................................................................................... 66

Table 1-25 Pickup feed components (1x550-sheet paper feeder) .................................................................................... 67

Table 1-26 Document feeder sensors ................................................................................................................................ 72

Table 1-27 Document feeder paper path ........................................................................................................................... 72

Table 2-1 Pre-boot menu options (1 of 7) .......................................................................................................................... 91

Table 2-2 Pre-boot menu options (2 of 7) .......................................................................................................................... 92

Table 2-3 Pre-boot menu options (3 of 7) .......................................................................................................................... 93

Table 2-4 Pre-boot menu options (4 of 7) .......................................................................................................................... 94

Table 2-5 Pre-boot menu options (5 of 7) .......................................................................................................................... 94

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Table 2-6 Pre-boot menu options (6 of 7) .......................................................................................................................... 95

Table 2-7 Pre-boot menu options (7 of 7) .......................................................................................................................... 96

Table 2-8 Troubleshooting owchart ............................................................................................................................... 108

Table 2-9 Heartbeat LED, product initialization ............................................................................................................... 141

Table 2-10 Heartbeat LED, product operational .............................................................................................................. 142

Table 2-11 Paper-path sensors diagnostic tests ............................................................................................................. 149

Table 2-12 Manual sensor diagnostic tests ..................................................................................................................... 152

Table 2-13 Tray/bin manual sensors ................................................................................................................................ 154

Table 2-14 Component test details .................................................................................................................................. 157

Table 2-15 Printer base, sensors and switches block diagram ....................................................................................... 161

Table 2-16 1x550-sheet paper feeder, sensors and switches block diagram ................................................................ 162

Table 2-17 Document feeder, sensors block diagram ..................................................................................................... 162

Table 2-18 Printer base cross section diagram ................................................................................................................ 163

Table 2-19 1x550-sheet paper feeder cross section diagram ........................................................................................ 164

Table 2-20 DC controller PCA ............................................................................................................................................ 165

Table 2-21 Formatter PCA ................................................................................................................................................ 167

Table 2-22 Formatter PCA ................................................................................................................................................ 168

Table 2-23 1x550-sheet paper feeder PCA ...................................................................................................................... 169

Table 2-24 Scan control board PCA .................................................................................................................................. 170

Table 2-25 External plug and port locations .................................................................................................................... 171

Table 2-26 Main assemblies, printer base (1 of 2) ........................................................................................................... 172

Table 2-27 Main assemblies, printer base (2 of 2) ........................................................................................................... 173

Table 2-28 PCA locations (printer base) ........................................................................................................................... 175

Table 2-29 Conguration page ......................................................................................................................................... 181

Table 2-30 HP embedded Jetdirect page ......................................................................................................................... 182

Table 2-31 Important information on the conguration pages ...................................................................................... 183

Table 2-32 Reports menu ................................................................................................................................................. 185

Table 2-33 General Settings menu ................................................................................................................................... 187

Table 2-34 Copy Settings menu (M577 only) ................................................................................................................... 201

Table 2-35 Scan/Digital Send Settings menu (M577 only) .............................................................................................. 209

Table 2-36 Fax Settings menu (M577 only) ..................................................................................................................... 219

Table 2-37 General Print Settings menu .......................................................................................................................... 232

Table 2-38 Default Print Options menu ........................................................................................................................... 235

Table 2-39 Display Settings menu ................................................................................................................................... 237

Table 2-40 Manage Supplies menu .................................................................................................................................. 239

Table 2-41 Manage Trays menu ....................................................................................................................................... 244

Table 2-42 Network Settings menu ................................................................................................................................. 246

Table 2-43 Wireless Menu ................................................................................................................................................ 246

Table 2-44 Embedded Jetdirect Menu .............................................................................................................................. 246

Table 2-45 Troubleshooting menu ................................................................................................................................... 257

Table 2-46 Backup/Restore menu .................................................................................................................................... 260

xviii ENWW

Table 2-47 Calibration/Cleaning menu (M577) ................................................................................................................ 260

Table 2-48 Call out Cable identication ........................................................................................................................... 295

Table 2-49 Call out Cable identication ........................................................................................................................... 302

Table 2-50 Sample event log page ................................................................................................................................... 389

Table 2-51 Repetitive defects .......................................................................................................................................... 393

Table 2-52 Print modes under the Adjust Paper Types submenu ................................................................................... 407

Table 2-53 Print modes under the Optimize submenu .................................................................................................... 407

Table 2-54 Image defects table ........................................................................................................................................ 409

Table 2-55 Printer feeds incorrect page size ................................................................................................................... 444

Table 2-56 Printer pulls from incorrect tray .................................................................................................................... 444

Table 2-57 Printer will not duplex (print 2-sided jobs) or duplexes incorrectly .............................................................. 444

Table 2-58 Paper does not feed from Tray 2-X ................................................................................................................ 445

Table 2-59 Output is curled or wrinkled ........................................................................................................................... 445

Table 2-60 Paper does not feed automatically ................................................................................................................ 447

Table 2-61 Printer base jam sensors ................................................................................................................................ 448

Table 2-62 1x550-sheet paper-feeder jam sensors ........................................................................................................ 449

Table 2-63 Document feeder, sensors block diagram ..................................................................................................... 449

Table 2-64 Solve performance problems ......................................................................................................................... 472

Table A-1 Operating-environment specications ............................................................................................................ 499

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List of gures

Figure 1-1 Relationship between the main printer systems ............................................................................................... 3

Figure 1-2 System block diagram ......................................................................................................................................... 4

Figure 1-3 Engine-control system ...................................................................................................................................... 11

Figure 1-4 DC controller block diagram .............................................................................................................................. 12

Figure 1-5 Low-voltage power-supply circuit .................................................................................................................... 18

Figure 1-6 High-voltage power supply circuits .................................................................................................................. 21

Figure 1-7 Fuser components ............................................................................................................................................ 23

Figure 1-8 Fuser temperature-control circuit .................................................................................................................... 25

Figure 1-9 Laser/scanner system ....................................................................................................................................... 27

Figure 1-10 Image-formation system ................................................................................................................................ 30

Figure 1-11 Motors ............................................................................................................................................................. 31

Figure 1-12 Sensors ............................................................................................................................................................ 32

Figure 1-13 Image-formation process ............................................................................................................................... 33

Figure 1-14 Pre-exposure .................................................................................................................................................. 35

Figure 1-15 Primary charging ............................................................................................................................................. 35

Figure 1-16 Laser-beam exposure ..................................................................................................................................... 36

Figure 1-17 Development ................................................................................................................................................... 36

Figure 1-18 Primary transfer .............................................................................................................................................. 37

Figure 1-19 Secondary transfer ......................................................................................................................................... 37

Figure 1-20 Separation ....................................................................................................................................................... 38

Figure 1-21 Fusing .............................................................................................................................................................. 38

Figure 1-22 ITB cleaning ..................................................................................................................................................... 39

Figure 1-23 Drum cleaning ................................................................................................................................................. 39

Figure 1-24 Toner cartridge system ................................................................................................................................... 41

Figure 1-25 Developer roller engagement and disengagement control ........................................................................... 43

Figure 1-26 ITB unit ............................................................................................................................................................ 45

Figure 1-27 Three states of primary-transfer roller engagement and disengagement ................................................... 46

Figure 1-28 ITB cleaning process ....................................................................................................................................... 48

Figure 1-29 Pickup, feed, and delivery system .................................................................................................................. 50

Figure 1-30 Photo sensors and switches ........................................................................................................................... 51

Figure 1-31 Motors, clutches, and solenoids ..................................................................................................................... 53

Figure 1-32 Tray 1 pickup mechanism ............................................................................................................................... 55

ENWW xxi

Figure 1-33 Tray 2 multiple-feed prevention ..................................................................................................................... 57

Figure 1-34 Skew-feed prevention ..................................................................................................................................... 58

Figure 1-35 Media sensors ................................................................................................................................................. 59

Figure 1-36 Jam detection sensors .................................................................................................................................... 61

Figure 1-37 Loop control mechanism ................................................................................................................................ 63

Figure 1-38 Pressure roller pressurization control ............................................................................................................ 63

Figure 1-39 550-sheet paper feeder .................................................................................................................................. 65

Figure 1-40 Tray 3-5 driver PCA ......................................................................................................................................... 66

Figure 1-41 Paper pickup and feed operation (550-sheet paper feeder) ......................................................................... 67

Figure 1-42 Jam detection (1x550-sheet paper feeder) ................................................................................................... 69

Figure 1-43 Document feeder sensors .............................................................................................................................. 72

Figure 1-44 Document feeder paper path ......................................................................................................................... 72

Figure 1-45 Deskew operation ........................................................................................................................................... 75

Figure 1-46 Document feeder open (book mode) .............................................................................................................. 76

Figure 1-47 Document feeder open (60º to 80º) ............................................................................................................... 76

Figure 2-1 Open the Pre-boot menu .................................................................................................................................. 88

Figure 2-2 Pre-boot menu .................................................................................................................................................. 89

Figure 2-3 Open the Pre-boot menu .................................................................................................................................. 90

Figure 2-4 Open the Control Panel ..................................................................................................................................... 99

Figure 2-5 Turn Windows features on or o ...................................................................................................................... 99

Figure 2-6 Enable the telnet client feature ...................................................................................................................... 100

Figure 2-7 Select the +3:Administrator item ................................................................................................................... 101

Figure 2-8 Select the +A:Remote Admin item .................................................................................................................. 101

Figure 2-9 Select the 1:Start Telnet item ......................................................................................................................... 101

Figure 2-10 Telnet connecting message .......................................................................................................................... 101

Figure 2-11 Telnet error message .................................................................................................................................... 102

Figure 2-12 Telnet server function initialized .................................................................................................................. 102

Figure 2-13 Open a command window ............................................................................................................................ 103

Figure 2-14 Start a telnet session .................................................................................................................................... 103

Figure 2-15 Establish a telnet connection ....................................................................................................................... 103

Figure 2-16 Enter the PIN ................................................................................................................................................. 104

Figure 2-17 Remote Admin window ................................................................................................................................. 104

Figure 2-18 Access the administrator menu .................................................................................................................... 105

Figure 2-19 Access the remote admin menu ................................................................................................................... 105

Figure 2-20 Terminate the telnet connection .................................................................................................................. 106

Figure 2-21 Diagnostic-tests access button .................................................................................................................... 113

Figure 2-22 Press the diagnostics-access button ............................................................................................................ 114

Figure 2-23 Diagnostic-tests access button .................................................................................................................... 114

Figure 2-24 Press the diagnostics-access button ............................................................................................................ 115

Figure 2-25 Control-panel version A yellow screen ......................................................................................................... 115

Figure 2-26 Exit the diagnostic mode .............................................................................................................................. 117

xxii ENWW

Figure 2-27 Open the Pre-boot menu .............................................................................................................................. 118

Figure 2-28 Pre-boot menu .............................................................................................................................................. 119

Figure 2-29 Access the administration menu .................................................................................................................. 120

Figure 2-30 Access the diagnostics menu ........................................................................................................................ 120

Figure 2-31 Open the screen test ..................................................................................................................................... 121

Figure 2-32 Blue vertical gradient screen ........................................................................................................................ 121

Figure 2-33 Open the touch test ...................................................................................................................................... 125

Figure 2-34 Touch the white grid ..................................................................................................................................... 125

Figure 2-35 Verify the mark ............................................................................................................................................. 126

Figure 2-36 Open the softkey test ................................................................................................................................... 127

Figure 2-37 Touch the Home button ................................................................................................................................ 127

Figure 2-38 Successful test .............................................................................................................................................. 128

Figure 2-39 Open the backlight test ................................................................................................................................. 129

Figure 2-40 Open the sound test ...................................................................................................................................... 130

Figure 2-41 Open the sound test ...................................................................................................................................... 131

Figure 2-42 Open the sound test ...................................................................................................................................... 132

Figure 2-43 Touchscreen blank, white, or dim (no image) .............................................................................................. 134

Figure 2-44 Touchscreen is slow to respond or requires multiple presses to respond ................................................... 135

Figure 2-45 Touchscreen has an unresponsive zone ....................................................................................................... 136

Figure 2-46 No control panel sound ................................................................................................................................. 137

Figure 2-47 Home button is unresponsive ....................................................................................................................... 138

Figure 2-48 Hardware integration pocket (HIP) is not functioning (control panel functional) ....................................... 139

Figure 2-49 Engine test button ........................................................................................................................................ 144

Figure 2-50 Defeating interlocks (front door) .................................................................................................................. 145

Figure 2-51 Defeating interlocks (right door; right side) ................................................................................................. 146

Figure 2-52 Defeating interlocks (right door; left side) ................................................................................................... 146

Figure 2-53 Printer base, sensors and switches block diagram ...................................................................................... 161

Figure 2-54 1x550-sheet paper feeder, sensors and switches block diagram ............................................................... 162

Figure 2-55 Document feeder, sensors block diagram .................................................................................................... 162

Figure 2-56 Printer base cross section diagram .............................................................................................................. 163

Figure 2-57 1x550-sheet paper feeder cross section diagram ....................................................................................... 164

Figure 2-58 DC controller PCA .......................................................................................................................................... 165

Figure 2-59 Formatter PCA ............................................................................................................................................... 167

Figure 2-60 Formatter PCA ............................................................................................................................................... 168

Figure 2-61 1x550-sheet paper feeder PCA .................................................................................................................... 169

Figure 2-62 Scan control board PCA ................................................................................................................................. 170

Figure 2-63 External plug and port locations .................................................................................................................. 171

Figure 2-64 Main assemblies, printer base (1 of 2) ......................................................................................................... 172

Figure 2-65 Main assemblies, printer base (2 of 2) ......................................................................................................... 173

Figure 2-66 PCA locations (printer base) ......................................................................................................................... 175

Figure 2-67 General timing chart ..................................................................................................................................... 176

ENWW xxiii

Figure 2-68 General circuit diagram (printer base) (1 of 2) ............................................................................................. 177

Figure 2-69 General circuit diagram (printer base) (2 of 2) ............................................................................................. 178

Figure 2-70 General circuit diagram 1x550-sheet paper feeder ..................................................................................... 179

Figure 2-71 Conguration page ....................................................................................................................................... 181

Figure 2-72 Conguration page ....................................................................................................................................... 182

Figure 2-73 Paper Tray guides ......................................................................................................................................... 275

Figure 2-74 Paper height guides ...................................................................................................................................... 275

Figure 2-75 Paper Tray guides ......................................................................................................................................... 277

Figure 2-76 Paper height guides ...................................................................................................................................... 277

Figure 2-77 Paper Tray guides ......................................................................................................................................... 279

Figure 2-78 Paper height guides ...................................................................................................................................... 279

Figure 2-79 Tray 1 Paper guides ...................................................................................................................................... 283

Figure 2-80 Tray 1 Paper height guides ........................................................................................................................... 283

Figure 2-81 Tray 2 Paper guides ...................................................................................................................................... 284

Figure 2-82 Tray 2 Paper height guides ........................................................................................................................... 284

Figure 2-83 Paper Tray guides ......................................................................................................................................... 287

Figure 2-84 Paper height guides ...................................................................................................................................... 287

Figure 2-85 500 Sheet paper tray door ............................................................................................................................ 364

Figure 2-86 Sample event log .......................................................................................................................................... 389

Figure 2-87 Examples of repetitive defects ..................................................................................................................... 394

Figure 2-88 Place the ruler on the page ........................................................................................................................... 395

Figure 2-89 Locate the next repetitive defect ................................................................................................................. 395

Figure 2-90 Determine the defective assembly ............................................................................................................... 396

Figure 2-91 Print-quality troubleshooting procedure ..................................................................................................... 398

Figure 2-92 Yellow print-quality troubleshooting page .................................................................................................. 398

Figure 2-93 Yellow comparison page ............................................................................................................................... 399

Figure 2-94 Black print-quality troubleshooting page .................................................................................................... 400

Figure 2-95 Open Tray 1 ................................................................................................................................................... 418

Figure 2-96 Open the roller cover .................................................................................................................................... 418

Figure 2-97 Remove the cover ......................................................................................................................................... 419

Figure 2-98 Release two tabs ........................................................................................................................................... 419

Figure 2-99 Remove the roller ......................................................................................................................................... 420

Figure 2-100 Release the tray retainers .......................................................................................................................... 420

Figure 2-101 Raise Tray 1 up ............................................................................................................................................ 421

Figure 2-102 Open the roller cover .................................................................................................................................. 421

Figure 2-103 Release one tab .......................................................................................................................................... 422

Figure 2-104 Remove the roller ....................................................................................................................................... 422

Figure 2-105 Clean the rollers .......................................................................................................................................... 423

Figure 2-106 Locate the keyed end of the roller and the holder ..................................................................................... 423

Figure 2-107 Install the roller .......................................................................................................................................... 424

Figure 2-108 Rotate the end of the roller into the holder ............................................................................................... 424

xxiv ENWW

Figure 2-109 Close the roller cover .................................................................................................................................. 425

Figure 2-110 Lower Tray 1 down ...................................................................................................................................... 425

Figure 2-111 Reconnect the tray retainers ...................................................................................................................... 426

Figure 2-112 Install the roller .......................................................................................................................................... 426

Figure 2-113 Reconnect two tabs .................................................................................................................................... 427

Figure 2-114 Install the roller cover ................................................................................................................................. 427

Figure 2-115 Close the roller cover .................................................................................................................................. 428

Figure 2-116 Close Tray 1 ................................................................................................................................................. 428

Figure 2-117 Pull the tray out .......................................................................................................................................... 429

Figure 2-118 Remove the tray ......................................................................................................................................... 429

Figure 2-119 Open the right door .................................................................................................................................... 430

Figure 2-120 Raise the transfer roller assembly ............................................................................................................. 430

Figure 2-121 Lower the paper guide ................................................................................................................................ 431

Figure 2-122 Locate the tray pickup roller ....................................................................................................................... 431

Figure 2-123 Slide the assembly to the left ..................................................................................................................... 432

Figure 2-124 Remove the roller assembly ....................................................................................................................... 432

Figure 2-125 Locate the roller assembly ......................................................................................................................... 433

Figure 2-126 Push up on the blue label ........................................................................................................................... 433

Figure 2-127 Remove the roller assembly ....................................................................................................................... 434

Figure 2-128 Clean the rollers .......................................................................................................................................... 434

Figure 2-129 Install the roller assembly .......................................................................................................................... 435

Figure 2-130 Fully seat the roller assembly .................................................................................................................... 435

Figure 2-131 Check the installation ................................................................................................................................. 436

Figure 2-132 Note of the mounting tab ........................................................................................................................... 436

Figure 2-133 Position the roller assembly in the printer ................................................................................................. 437

Figure 2-134 Release the spring loaded shaft ................................................................................................................. 437

Figure 2-135 Verify the roller installation ....................................................................................................................... 438

Figure 2-136 Install the tray ............................................................................................................................................. 438

Figure 2-137 Close the tray .............................................................................................................................................. 439

Figure 2-138 Printer base jam sensors ............................................................................................................................ 448

Figure 2-139 1x550-sheet paper-feeder jam sensors .................................................................................................... 449

Figure 2-140 Document feeder jam sensors ................................................................................................................... 449

Figure 2-141 Open the Pre-boot menu ............................................................................................................................ 480

Figure 2-142 Open the Pre-boot menu ............................................................................................................................ 483

Figure 2-143 Open the Pre-boot menu ............................................................................................................................ 484

Figure 2-144 Open the Pre-boot menu ............................................................................................................................ 489

Figure A-1 Dimensions for the M552dn and M553n/dn models ...................................................................................... 494

Figure A-2 Dimensions for the M553x model .................................................................................................................. 494

Figure A-3 Dimensions for the M577 models .................................................................................................................. 495

Figure A-4 Dimensions for the 1 x 550-sheet paper feeder ............................................................................................ 495

Figure A-5 Dimensions for the cabinet/stand .................................................................................................................. 496

ENWW xxv

Figure A-6 Dimensions for the M552 and M553 models with one 1 x550-sheet tray and the cabinet/stand ............... 497

Figure A-7 Dimensions for the M577 models with three 1 x 550-sheet paper feeders and the cabinet/stand ............. 498

Figure A-8 Certicate of Volatility (M522/M553; 1 of 2) .................................................................................................. 500

Figure A-9 Certicate of Volatility (M522/M553; 2 of 2) .................................................................................................. 501

Figure A-10 Certicate of Volatility (M577; 1 of 2) .......................................................................................................... 502

Figure A-11 Certicate of Volatility (M577; 2 of 2) .......................................................................................................... 503

xxvi ENWW

1 Theory of operation

●

For additional service and support

●

Basic operation

●

Formatter-control system

●

Engine-control system

●

Engine laser/scanner system

●

Pickup, feed, and delivery system

●

Input accessories

●

Scanning and image capture system (M577)

●

Document feeder system (M577)

ENWW 1

For additional service and support

HP service personnel, go to the Service Access Work Bench (SAW) at http://h41302.www4.hp.com/km/saw/

home.do.

Channel partners, go to HP Channel Services Network (CSN) at https://h30125.www3.hp.com/hpcsn.

At these locations, nd information on the following topics:

●

Install and congure

●

Printer specications

●

Up-to-date control-panel message (CPMD) troubleshooting

●

Solutions for printer issues and emerging issues

●

Remove and replace part instructions and videos

●

Service advisories

●

Warranty & regulatory information

To access HP PartSurfer information from any mobile device, go to http://partsurfermobile.hp.com/ or scan the Quick Response (QR) code below.

2 Chapter 1 Theory of operation ENWW

Basic operation

Engine-control system

Laser scanner system

Image-formation system

Pickup, feed, and delivery system

Accessory

Image Scanner (M577)

The printer routes all high-level processes through the formatter, which stores font information, processes the print image, and communicates with the host computer.

The basic printer operation comprises the following 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 pickup, feed, and delivery system, which uses a system of rollers and belts to transport the paper through the printer

●

Accessory (optional paper feeder)

●

Image scanner (M577)

Figure 1-1 Relationship between the main printer systems

ENWW Basic operation 3

Figure 1-2 System block diagram

Formatter

Easy-access

USB

DC controller

Control

Panel

Low-voltage power supply (LVPS)

Image scanner

(M577)

Scanner control board (M577)

LAN

USBD

USBH

4 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 printer exits Sleep mode until the printer is ready for printing.

Standby From the end of the waiting sequence, the last

rotation until the formatter receives a print command, or until the printer is turned o.

●

Detects the fuser

●

Heats the fuser sleeve in the fuser

●

Pressurizes the pressure roller in the fuser

●

Detects the toner cartridges

●

Separates all of the developing rollers from the photosensitive drums in the toner cartridges

●

Separates all of the transfer rollers from the photosensitive drums in the toner cartridges

●

Rotates and stops each motor

●

Rotates and stops each fan

●

Detects the ITB

●

Cleans the ITB and secondary transfer roller

●

Is in the Ready state

●

Enters Sleep mode if the formatter sends the sleep command

●

Rotates and stops each fan

●

Calibrates if the formatter sends the calibration command

Initial rotation From the time the formatter receives a print command

until the paper enters the paper path.

●

Rotates each motor

●

Rotates each fan

●

Activates the high-voltage power supply

●

Prepares the laser/scanner unit

●

Warms the fuser to the correct temperature

ENWW Basic operation 5

Table 1-1 Sequence of operation (continued)

Period Duration Description

Printing From the time the rst sheet of paper enters the paper

path until the last sheet has passed through the fuser.

Last rotation From the time the last sheet of paper exits the fuser

until the motors stop rotating.

●

Forms the image on the photosensitive drums

●

Transfers the toner to the paper

●

Fuses the toner image onto the paper

●

Moves the last printed sheet into the output bin

●

Stops each motor

●

Stops each fan

●

Stops the high-voltage power supply

●

Stops the laser/scanner unit

●

Turns the fuser heater o

●

If another print command is received, the printer enters the initial rotation period when the last rotation is complete.

6 Chapter 1 Theory of operation ENWW

Formatter-control system

The formatter performs the following functions:

●

Controls sleep mode

●

Receives and processes print data from the various printer interfaces

●

Monitors control panel functions and relays printer status information through the control panel and the network or bi-directional interface

●

Develops and coordinates data placement and timing with the DC controller PCA

●

Stores font information

●

Communicates with the host computer through the network or the bidirectional interface

The formatter receives a print job from the network or bidirectional interface and separates it into image information and instructions that control the printing process. The DC controller PCA synchronizes the image formation system with the paper input and output systems, and then signals the formatter to send the print image data.

Sleep mode

NOTE: In the General Settings menu (a submenu of the Administration menu), this item is termed Sleep

Timer Settings.

This feature conserves power after the printer has been idle for an adjustable period of time. When the printer is in Sleep mode, the printer retains all settings, downloaded fonts, and macros. The default setting is for Sleep mode to be enabled, and the printer enters Sleep mode after a 30-second idle time.

The printer rmware uses a combination of timers and Sleep settings to control when the printer enters a dierent state as well as what states the printer will enter. The available states are listed below, in descending order, from using the most power to using the least power:

●

Active: The printer control panel is fully illuminated. The power button light is illuminated.

●

Shallow sleep: The printer control panel is dim and the content is grayed out, but is still readable. The power button light is illuminated.

●

Sleep: The printer control panel is o (blacked out). The power button light blinks once every three seconds.

●

Deep sleep: The printer control panel is o (blacked out). The power button light blinks once every three seconds. The control panel and power button appearance is the same in this state as the sleep state. However, the printer is drawing less than 1 watt of power in the deep sleep state (as opposed to 6 watts of power in the sleep state).

●

O: This state is entered by pressing the power button or removing power from the printer. The power button light is not illuminated.

NOTE: In some countries/regions, Sleep mode cannot be turned o.

The printer exits Sleep mode and enters the warm-up cycle when any of the following events occur:

●

The printer receives a print job, valid data, or a PML or PJL command.

●

A control-panel button is pressed or the touchscreen is touched.

ENWW Formatter-control system 7

●

A cover or door is opened.

●

The engine self-test switch is pressed.

●

A paper tray, other than Tray 1, is opened.

NOTE: If the printer is in the deep sleep state, opening a paper tray will not cause the printer to exit

Sleep mode.

NOTE: Printer error messages override the Sleep message. The printer enters Sleep mode at the

appropriate time, but the error message continues to appear.

TIP: When the printer is in Sleep mode, the sub-power supply is o and the low-voltage power supply is on.

Printer job language (PJL)

PJL is an integral part of printer conguration, in addition to the standard printer command language (PCL) and PostScript (PS). With standard cabling, the printer can use PJL to perform a variety of functions, such as these:

●

Two-way communication with the host computer through a network connection or a USB device port: The printer can inform the host about the control-panel settings, and the control-panel settings

can be changed from the host.

●

Dynamic I/O switching: The printer uses this switching to be congured with a host on each I/O. The printer can receive data from more than one I/O simultaneously, until the I/O buer is full. This can occur even when the printer is oine.

●

Context-sensitive switching: The printer can automatically recognize the personality (PS or PCL) of each job and congure itself to serve that personality.

●

Isolation of print environment settings from one print job to the next: For example, if a print job is sent to the printer in landscape mode, the subsequent print jobs print in landscape only if they are formatted for landscape printing.

Printer management language (PML)

PML allows remote conguration of the printer and status read-back from the printer through the I/O ports.

Control panel

The M552dn, M553n and M553dn control panel is a 6.85 cm (2.7 in) four-line color display with numeric keypad and additional buttons for navigating control panel menus. The M553x control panel is a 10.9 cm (4.3 in) full-color SVGA with infrared touchscreen and adjustable viewing angle. The M577 control panel is a 20.3 cm (8 in) full-color SVGA with infrared touchscreen and adjustable viewing angle.

The M553x and M577 control panels have a diagnostic mode to allow testing of the touchscreen, Home button, and speaker. The control panels do not require calibration.

8 Chapter 1 Theory of operation ENWW

Easy-access USB port

This printer features easy-access USB printing, for quickly printing les without sending them from a computer. The printer accepts standard USB ash drives in the USB port near the control panel. It supports the following types of les:

●

.pdf

●

.prn

●

.pcl

●

.ps

●

.cht

The USB port is disabled by default. Follow the instructions in the printer user guide to enable the USB port and print USB documents.

Wireless

The M553x and M577z models contain a wireless card to enable wireless direct printing over a 802.11b/g/n wireless connection.

NOTE: This card does not enable the printer to connect to the network.

Near eld communication (NFC)

The M553x and M577z models support NFC capabilities. NFC enables a connection between the printer and a mobile device, such as a smartphone or tablet, by touching the device to the NFC icon on the bottom of the control panel. Documents and images from the mobile device can then be printed through the wireless card on the printer

CPU

The formatter incorporates a 1.2 GHz processor.

Input/output (I/O)

The printer has three I/O interfaces:

●

Hi-Speed USB 2.0

●

10/100/1000 Ethernet LAN connection with IPv4 and IPv6

●

Easy-access USB printing (no computer required)

Memory

The formatter incorporates dierent types of memory and storage to store the printer rmware as well as print-job data and user settings.

ENWW Formatter-control system 9

Firmware

The embedded MultiMedia Card (eMMC) on the formatter stores the rmware for the M552 and M553 models. The hard disk drive (HDD) on the formatter stores the rmware for the M577 models. A remote rmware upgrade process is used to overwrite and upgrade the rmware.

Nonvolatile random access memory (NVRAM)

The printer uses NVRAM to store printer and user conguration settings. The contents of NVRAM are retained when the printer is turned o or disconnected.

Random access memory (RAM)

The RAM on the formatter serves as a temporary storage area for printing and system operation.

HP Memory Enhancement technology (MEt)

MEt eectively doubles the amount of standard memory through a variety of font- and data-compression methods.

NOTE: MEt is available only in when printing in printer command language (PCL) mode. It is not functional

when printing in PostScript (PS) mode.

10 Chapter 1 Theory of operation ENWW

Engine-control system

Formatter

Engine-control system

DC controller

Low-voltage power supply

Laser scanner system

Image-formation system

Pickup, feed, and delivery

system

Accessory

High-voltage power supplies

Fuser power supply

Image Scanner (M577)

Formatter

Engine-control system

DC controller

Low-voltage power suppl

Laser scanner system

Image-formation system

Pickup, feed, and delivery

stem

Accessor

igh-voltage power supplies

Fuser power suppl

Image Scanner (M577

)

The engine-control system receives commands from the formatter and interacts with the other main systems to coordinate all printer functions. The engine-control system consists of the following components:

●

DC controller

●

One low-voltage power supply

●

Two high-voltage power supplies

●

One fuser power supply

Figure 1-3 Engine-control system

ENWW Engine-control system 11

LED

Motor

Fan

Solenoid

LED

Accessory

HIP

Fuser

AC input

Photointerrupter

Sensor

Motor

Fan

T2 roller

Cartridge

(Y/M/C/K)

High-voltage

power supply T

Fuser

power supply

DC controller

Low-voltage

power supply

Motor

Fan

Solenoid

Photointerrupter

Switch

ITB ass’y

Laser scanner ass’y

Control panel

Formatter

Clutch

Sensor

High-voltage

power supply D

Fan

Sensor

LED

tor

olenoi

Accessor

inpu

Photointerrupter

ensor

tor

T2 roller

artrid

Y/M

/C/K)

igh-volta

ower supply

use

ower suppl

DC controller

Low-volta

ower supp

tor

olenoi

Photointerrupter

witc

ITB ass

’y

Laser scanner ass

’y

ontrol panel

Formatter

lutc

ensor

igh-volta

ower supply D

ensor

DC controller

The DC controller controls the operation of the printer and its components. The DC controller starts the printer operation when the printer power is turned on and the power supply sends DC voltage to the DC controller. After the printer enters the standby period, the DC controller sends out various signals to operate motors, solenoids, and other printer components based on the print command and image data that the host computer sends.

Figure 1-4 DC controller block diagram

12 Chapter 1 Theory of operation ENWW

Motors

The printer has eight motors. The motors drive the components in the paper-feed and image-formation systems.

The DC controller monitors the fuser motor; the scanner motor, and drum motors 1, 2, and 3 to determine if a motor has failed. It noties the formatter when it encounters the following conditions:

●

Startup failure: the motor does not reach a specied speed within a specied time from when the motor starts.

●

Rotational failure: the rotational speed of the motor is not in the specied range for a specied time after the motor reaches a specied speed.

Table 1-2 Motors

Abbreviation Name Purpose Failure

detection

M1 Drum motor 1 Drives the yellow photosensitive

drum, yellow developing roller, and magenta developing roller

M2 Drum motor 2 Drives the magenta photosensitive

drum, cyan photosensitive drum, and cyan developing roller

M3 Drum motor 3 Drives the black photosensitive

drum, black developing roller, and ITB

M4 Fuser motor Drives the pressure roller and

delivery roller; the pressurization and release of the pressure roller; and the engagement and disengagement of the primary and secondary transfer rollers

M5 Pickup motor Drives the registration roller, Tray 1

pickup roller, Tray 2 pickup roller, and Tray 2 feed roller

M6 Developer disengagement

motor

Drives the engagement and disengagement of the developing rollers

Yes Drum motor

Yes Fuser drive assembly

No Paper pickup drive

No Stepping motor

Replacement part number

(RM2-0078-000CN)

(RM2-0009-000CN)

assembly (RM2-0008-000CN)

(RK2-6027-000CN)

M7 Scanner motor Drives the scanner mirror Yes Laser scanner assembly

(RM2-6545-000CN)

M8 Duplex reverse motor

(M552dn, M553dn, M553x, and M577 only)

Drives the duplex reverse roller No Duplex drive assembly

(RM2-0006-000CN)

ENWW Engine-control system 13

Fans

The printer has four fans for preventing the temperature from rising in the printer and for cooling the printed pages.

The DC controller determines if there is a fan failure and noties the formatter if the fan locks for a specied time from when the fan starts.

Table 1-3 Fans

Abbreviation Name Cooling area Type Speed Replacement part

number

Solenoids

Clutches

FM1 Power supply fan Around the low-voltage

power supply unit

FM2 Cartridge fan Around the toner cartridges Intake Full Fan

FM3 Delivery fan Around the output tray

Around the fuser area

FM4 Fuser fan Around the fuser Exhaust Full/half Fan

Table

1-4 Solenoids

Abbreviation Component name

SL1 Primary transfer roller disengagement solenoid

SL2 Tray 1 pickup solenoid

SL3 Duplex reverse solenoid (M552dn, M553dn, M553x, and M577 only)

Intake Full/half Fan

Exhaust Full/half Fan

(RK2-2416-000CN)

(RK2-6124-000CN)

(RK2-2728-000CN)

(RK2-2418-000CN)

Table

1-5 Clutches

Abbreviation Component name

CL1 Tray 2 pickup clutch

CL2 Duplex re-pickup clutch (M552dn, M553dn, M553x, and M577 only)

Switches

1-6 Switches

Table

Abbreviation Component name Replacement part number

SW1 24V interlock switch Interlock switch cable assembly (RM2-7206-000CN; part not

available)

SW3 Right door switch Switch button (WC2-5806-000CN; part not available)

14 Chapter 1 Theory of operation ENWW

Table 1-6 Switches (continued)

Abbreviation Component name Replacement part number

SW4 Power supply switch Lever, switch (RC4-0131-000CN; part not available)

SW5 Tray 2 detection switch Switch button (WC2-5806-000CN; part not available)

SW1001 Test print switch Part not available

ENWW Engine-control system 15

Sensors

Table 1-7 Sensors

Abbreviation Component name Replacement part

PS1 Loop sensor Part not available

SE1 Media sensor Registration assembly

●

RM2-0093-000CN (M553n)

●

RM2-0018-000CN (M552dn, M553dn, M553x, M577)

SR1 Drum home position sensor 1 Part not available

SR2 Drum home position sensor 2 Part not available

SR3 Drum home position sensor 3 Part not available

SR4 Developing home position sensor Part not available

SR5 Primary transfer roller disengagement sensor Estrangement detect PCA assembly (RM2-7157-000CN)

SR6 Top-of-page (TOP) sensor (M552dn, M553dn,

M553x and M577 only)

SR6N Top-of-page (TOP) sensor (M553n only) Part not available

SR8 Tray 1 media-out sensor Part not available

SR9 Fuser delivery sensor Part not available

SR10 Output bin media-full sensor Part not available

SR11 Fuser pressure release sensor Photointerrupter (WG8-5953-000CN; part not available)

SR12 Tray 2 media-out sensor Part not available

SR13 Media width sensor, front (M552dn, M553dn,

M553x and M577 only)

SR13N Media width sensor, front (M553n only) Part not available

SR14 Media width sensor, rear (M552dn, M553dn, M553x

and M577 only)

SR14N Media width sensor, rear (M553n only) Part not available

Registration density sensor Density detect assembly (RM2-7160-000CN)

Environment sensor (temperature and humidity) Environment sensor PCA (RM2-7154-000CN)

Yellow toner-level sensor Cartridge lift-up rail assembly (RM2-0025-000CN; part

Part not available

not available)

Magenta toner-level sensor Cartridge lift-up rail assembly (RM2-0025-000CN; part

not available)

Cyan toner-level sensor Cartridge lift-up rail assembly (RM2-0025-000CN; part

not available)

Black toner-level sensor Cartridge lift-up rail assembly (RM2-0025-000CN; part

not available)

Residual toner collection unit full sensor Waste toner detect PCA (RM2-7130-000CN)

16 Chapter 1 Theory of operation ENWW

Table 1-7 Sensors (continued)

Abbreviation Component name Replacement part

Pre-exposure LED 1-3 Pre-exposure PCA (RM2-7168-000CN)

Pre-exposure LED 4 Pre-exposure PCA (RM2-7169-000CN)

ENWW Engine-control system 17

Low-voltage power supply

+3.3VA

+5VB

VC5VOFF

PWRSAVE

+24VB

ZEROX

+5VA

+24VA

+3.3VA

+3.3VC

24VRMT

+3.3VC +3.3VD

POWER_SW

+5VA

FET

+3.3VB

+5VC

FET

+3.3VB2

AC input

Low-voltage power supply

DC controller

Fuse

FU100

Interlock switch

SW1

Rectifying

circuit

Zerocross

circuit

+3.3V

generation

circuit

+24V

generation

circuit

+5V

generation

circuit

Fuser

Power switch

SW4

Rectifying

circuit

Protection

circuit

Fuse

FU101

Fuser power supply

Protection

circuit

Switching

circuit

Formatter

The low-voltage power-supply (LVPS) circuit converts the AC power from the wall receptacle into the DC voltage that the printer components use.

Figure 1-5 Low-voltage power-supply circuit

18 Chapter 1 Theory of operation ENWW

Low-voltage power supply voltages description

The low-voltage power supply converts the AC power into three DC voltages, which it then subdivides, as described in the following table.

Table 1-8 Converted DC voltages

Main DC voltage Sub-voltage Behavior

+24 V +24 VA Constantly supplied

Stopped during active OFF or inactive OFF

+24 VB Interrupted when the right door is open (SW1)

+24 VC Interrupted when the right door is open (SW1)

+5 V +5 VA Constantly supplied

+5 VB Constantly supplied

+5 VC Constantly supplied

Stopped during active OFF or inactive OFF

+3.3 V +3.3 VA Constantly supplied

+3.3 VB Constantly supplied

Stopped during inactive OFF

+3.3 VC Constantly supplied

+3.3 VD Constantly supplied

Over-current/over-voltage protection

The low-voltage power supply automatically stops supplying the DC voltage to the printer components whenever it detects excessive current or abnormal voltage. The low-voltage power supply has a protective circuit against over-current and over-voltage to prevent failures in the power supply circuit.

CAUTION: 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 switch o and unplug the power cord.

Do not turn the power switch on until the root cause is found and corrected.

If the protective function is active, the DC controller noties the formatter of a low-voltage power supply failure. In addition, the low-voltage power supply has two fuses to protect against over-current. If overcurrent ows into the AC line, the fuse stops the AC power.

Sleep mode operation

Stopped during active OFF or inactive OFF

Sleep mode conserves energy by stopping the power to several components when the printer is idle. If the DC controller detects voltage that is too high when the printer is in Sleep mode, it determines that the lowvoltage power supply has failed, and it noties the formatter.

ENWW Engine-control system 19

Low-voltage power supply failure detection

The DC controller determines a low-voltage power supply failure and noties the formatter when the lowvoltage power supply does not supply +24 V.

Low-voltage power supply functions

The printer has the following low-voltage power supply functions.

Table 1-9 Low-voltage power supply functions

Function Supported feature

Sleep mode Yes

Power supply voltage detection Yes

Automatic power OFF Yes

Automatic power ON/OFF Yes

Active OFF Yes

Inactive OFF Yes

Network mode No

Power switch illumination Yes

Low-voltage power supply failure detection Yes

Power save mode No

High-voltage power supply

The DC controller controls the high-voltage power supply (HVPS) to generate biases. The high-voltage power supply delivers the high-voltage biases to the following components used to transfer toner during the imageformation process:

●

Primary charging roller (in the toner cartridges)

●

Developing roller (in the toner cartridges)

●

Primary transfer roller

●

Secondary transfer roller

●

Pressure roller

●

ITB cleaning brush

20 Chapter 1 Theory of operation ENWW

High-voltage power supply circuits

High-voltage power supply D

Primary transfer bias circuit Fusing bias circuit

Pressure roller

Secondary transfer roller

Secondary transfer

bias circuit

Primary charging bias

circuit

Developing bias circuit

DC controller

Primary transfer roller

High-voltage power supply T

ITB cleaning

brush

igh-voltage power supply D

Primary transfer bias circui

using bias circui

essure rolle

econdary transfer

bias circuit

Primary charging bias

ircui

eveloping bias circui

controller

igh-voltage power supply

ITB cleaning

ush

The high-voltage power supply contains the following separate circuits.

Figure 1-6 High-voltage power supply circuits

Table 1-10 High-voltage power supply circuits

Circuit Description

Primary-charging-bias generation The primary charging bias negatively charges the surface of the photosensitive drum to

ENWW Engine-control system 21

prepare for image formation.

Table 1-10 High-voltage power supply circuits (continued)

Circuit Description

Developing-bias generation The developing bias adheres toner to an electrostatic latent image formed on the

Primary-transfer-bias generation The primary transfer bias transfers the toner from each photosensitive drum onto the

Secondary-transfer-bias generation The positive secondary transfer bias transfers the toner image from the ITB onto the

Fuser bias

The printer uses instant-on fusing. The fuser bias is DC positive for improved print quality. The fuser bias circuit is located in the high-voltage power supply, HVPS (T).

Fuser control

The DC controller and components in the fuser perform the following functions related to fuser operation:

●

Control fuser temperature

●

Detect fuser failures

photosensitive drums.

ITB.

paper. The negative 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 unit.

●

Fuser circuits

The fuser heater control circuit and the fuser heater safety circuit control the fuser temperature according to commands from the DC controller. The fuser consists of the following major components:

Prevent excessive temperature rise

Detect remaining life in the fuser

Determine if the correct fuser is installed

22 Chapter 1 Theory of operation ENWW

Figure 1-7 Fuser components

TH2

TH3

TH1

TP1

H1, H2

Fuser heater safety

circuit

Fuser film

Pressure roller

FUSER TEMPERATURE signal

FUSER HEATER CONTROL signal

DC controller

Fuser heater control

circuit

Fuser power supply

Fuser heater safet

ircui

user f

ilm

essure rolle

FUSER TEMPERATURE signal

FUSER HEATER CONTROL signal

DC controller

use

r heater control

ircui

Fuser power suppl

Table 1-11 Fuser components

Type of component Abbreviation Name Function

Heaters H1 Fuser main heater Heats the center of the fuser sleeve

Thermistors

(Contact type)

H2 Fuser sub-heater Heats the edge of the fuser sleeve

TH1 Main thermistor Detects the center temperature of

TH2 Sub-thermistor 1 Detects the temperature at one end

the fuser heater

of the fuser heater

ENWW Engine-control system 23

Table 1-11 Fuser components (continued)

Type of component Abbreviation Name Function

TH3 Sub-thermistor 2 Detects the temperature at one end

of the fuser heater

Thermoswitch

(Non-contact type)

Fuser control functions

The printer has the following fuser control functions.

Table 1-12 Low-voltage power supply functions

Failure detection function Supported feature

Fuser temperature control Yes

Fuser failure detection Yes

Frequency detection circuit failure detection Yes

Fuser pressure release mechanism failure detection Yes

Fuser type discrepancy detection Yes

Fuser type identication detection Yes

Fuser presence detection Yes

Fuser life detection Yes

Relay failure detection No

TP1 Thermoswitch Prevents an abnormal temperature

rise in the fuser heater

Pressure roller cleaning Yes

Fuser temperature control

The temperatures of the two rollers in the fuser uctuate according to the stage of the printing process. The DC controller sends commands to the fuser-control circuit to adjust temperatures.

24 Chapter 1 Theory of operation ENWW

/ZEROX

/RLD2

FSRD_MAIN

FSR_TH_SUB_F

FSRD_SUB

RLD1

RL6001

RL6002

H1, H2

TH3

TH2

TH1

FSR_TH_MAIN

FSR_TH_SUB_R

FSR_SNS

FSR_TYPE100

FSR_TH_SUB_R

FSR_TH_MAIN

+24VC

+24VB

+24VC

AC input

DC controller

Low-voltage

power supply

Fuser

Pressure roller

Fuser sleeve ass’y

Zerocross

circuit

Fuser heater

control circuit

Relay control

circuit

Fuser

power supply

Fuser heater safety circuit

Relay control

circuit

Figure 1-8 Fuser temperature-control circuit

ENWW Engine-control system 25

Fuser heater protection

Fuser heater protection is a feature that detects excessive temperatures in the fuser and interrupts the power supply to the fuser heater.

The following three protective components prevent the fuser heater from excessive rising temperature:

●

DC controller: When a thermistor or sub-thermistor detects a temperature above a certain threshold, the DC controller interrupts power to the specic heater.

●

Fuser-heater safety circuit: The fuser heater safety circuit monitors the detected temperature of the sub-thermistors.

●

Thermoswitch: If the temperature in the heaters is abnormally high, and the temperature in the thermoswitch exceeds a specied value, the contact to the thermoswitch breaks.

Fuser unit life detection

The fuser life is tracked by fuser rotations, and not by the number of pages printed. This is a more accurate tracking method since the fuser rotates for every print job. There will be variations in fuser life depending on customer usage. Customers who are running one- and two-page intermittent jobs with long pauses between each job might reach the fuser low message sooner due to the fuser rotating more times per page than it would for larger print jobs.

Fuser identication

The printer detects the type and presence of the fuser. The DC controller noties the formatter when it fails to detect the type or presence of the fuser.

NOTE: This printer detects if a fuser of the correct voltage for the printer is installed. If a fuser of the

incorrect voltage is installed, the DC controller noties the formatter and an error message is displayed on the control panel.

26 Chapter 1 Theory of operation ENWW

Engine laser/scanner system

Scanner motor assembly

Scanner mirror

Laser assembly

BD sensor

DC controller

Photosensitive drum

The laser/scanner system forms the latent electrostatic image on the photosensitive drums inside each of the toner cartridges.

The DC controller receives instructions from the formatter regarding the image of the page to be printed. The DC controller signals the lasers to emit light, and the laser beams pass through lenses and onto the scanner mirror, which rotates at a constant speed. The mirror reects the beam onto the photosensitive drum in the pattern required for the image, exposing the surface of the drum so it can receive toner.

The main components of the laser/scanner system are the laser assembly and the scanner motor assembly, which are controlled by signals sent from the DC controller.

Figure 1-9 Laser/scanner system

ENWW Engine laser/scanner system 27

Laser/scanner failure detection

The DC controller determines an optical unit failure and noties the formatter of the error status when any of the following occurs:

●

Laser/scanner motor startup failure: The scanner motor does not reach a specied rotation frequency within a specied period of time from when the laser/scanner starts up.

●

Laser/scanner motor abnormal rotation: The laser/scanner motor does not reach a specied rotational frequency within a specied period of time during a print operation.

Safety

The laser/scanner assembly has a mechanical laser shutter. For the safety of users and service technicians, the laser shutter interrupts the optical path of the laser/scanner assembly when the top door is opened (SW101).

28 Chapter 1 Theory of operation ENWW

Image-formation process

The image-formation system creates the printed image on the paper. The system consists of the following components:

●

Toner cartridges

●

Intermediate transfer belt (ITB)

●

Primary transfer roller

●

Secondary transfer roller

●

Fuser

●

Laser/scanner

●

High-voltage power supply D

●

High-voltage power supply T

The DC Controller controls the internal components of the image formation system (according to commands received from the formatter) to form the toner image on the photosensitive drum surface. The toner image is then transferred to the print media and fused.

ENWW Engine laser/scanner system 29

Figure 1-10 Image-formation system

Laser/scanner

DC controller

Fuser

Cartridge

ITB

Primary transfer roller

High-voltage power supply T

High-voltage power supply D

Secondary

transfer

roller

The following gure shows the motors for the image-formation system.

30 Chapter 1 Theory of operation ENWW

Figure 1-11 Motors

DC controller

M3 M4

Table 1-13 Motors

Abbreviation Component Replacement part number

M1 Drum motor 1 Drum motor assembly (RM2-0078-000CN)

M2 Drum motor 2 Drum motor assembly (RM2-0078-000CN)

M3 Drum motor 3 Drum motor assembly (RM2-0078-000CN)

M4 Fuser motor Fuser motor assembly (RM2-0077-000CN)

M6 Developer disengagement motor Stepping motor (RK2-6027-000CN)

The following gure shows the sensors for the image-formation system.

ENWW Engine laser/scanner system 31

Figure 1-12 Sensors

SR4

SR5

SR1

SR2

SR3

DC controller

Environmental

sensor

Y toner level

sensor

M toner level

sensor

C toner level

sensor

K toner level

sensor

Registration

density sensor

SE1

Toner collection unit full sensor

Table 1-14 Sensors

Abbreviation Component Replacement part number

SR1 Drum home position sensor 1 Main motor drive assembly (B5L25-67902)

SR2 Drum home position sensor 2 Main motor drive assembly (B5L25-67902)

SR3 Drum home position sensor 3 Main motor drive assembly (B5L25-67902)

SR4 Developing home position sensor Main motor drive assembly (B5L25-67902)

SR5 Primary transfer roller disengagement sensor Estrangement detect PCA assembly (RM2-7157-000CN)

SE1 Media sensor Registration assembly

Yellow toner-level sensor Part not available

Magenta toner-level sensor Part not available

Cyan toner-level sensor Part not available

Black toner-level sensor Part not available

Registration density sensor Density detect assembly (RM2-7160-000CN)

Environmental sensor Environmental sensor PCA assembly (RM2-7154-000CN)

Toner collection unit full sensor Waste toner detect PCA assembly (RM2-7130-000CN)

●

RM2-0093-000CN (M553n)

●

RM2-0018-000CN (M552dn, M553dn, M553x, M577)

32 Chapter 1 Theory of operation ENWW

Table 1-14 Sensors (continued)

: Paper path

: Direction of drum rotation

: Functional block

: Step

Pickup

Delivery

Fusing

Transfer

Drum cleaning

Developing

Latent image formation

8. Fusing

7. Separation

6. Secondary transfer

10. Drum cleaning

2. Primary charging 1. Pre-exposure

3. Laser-beam exposure

5. Primary transfer

4. Developing

YMC K

ITB cleaning

9. ITB cleaning

Abbreviation Component Replacement part number

Pre-exposure LEDs 1, 2, and 3 Pre-exposure PCA assembly (RM2-7168-000CN)

Pre-exposure LED 4 Pre-exposure PCA assembly (RM2-7169-000CN)

The image-formation process consists of ten steps divided into six functional blocks.

Figure 1-13 Image-formation process

ENWW Engine laser/scanner system 33

Table 1-15 Image formation process

Functional block Steps Description

Latent image formation 1. Pre-exposure

2. Primary charging

3. Laser-beam exposure

Development 4. Development Toner adheres to the electrostatic latent image on the

Transfer 5. Primary transfer

6. Secondary transfer

7. Separation

An invisible latent image forms on the surface of the photosensitive drums.

photosensitive drums.

The toner image transfers to the ITB and then to the paper.

Table 1-15 Image formation process (continued)

Functional block Steps Description

Fusing 8. Fusing The toner fuses to the paper to make a permanent

ITB cleaning 9. ITB cleaning Residual toner is removed from the ITB.

Drum cleaning 10. Drum cleaning Residual toner is removed from the photosensitive

image.

drums.

34 Chapter 1 Theory of operation ENWW

Step 1: Pre-exposure

LED

Photosensitive drum

Primary charging roller

Primary charging bias

Light from the pre-exposure LED strikes the surface of the photosensitive drum to remove any residual electrical charges from the drum surface.

Figure 1-14 Pre-exposure

Step 2: Primary charging

The primary-charging roller contacts the photosensitive drum and charges the drum with negative potential.

Figure 1-15 Primary charging

ENWW Engine laser/scanner system 35

Step 3: Laser-beam exposure

Photosensitive drum

Laser beam

Developer roller

Developing bias

Photosensitive drum

Developer blade

The laser beam strikes the surface of the photosensitive drum in the areas where the image will form. The negative charge neutralizes in those areas, which are then ready to accept toner.

Figure 1-16 Laser-beam exposure

Step 4: Development

Toner acquires a negative charge as the developing cylinder contacts the developing blade. Because the negatively-charged surface of the photosensitive drums have been neutralized where they have 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.

Figure 1-17 Development

36 Chapter 1 Theory of operation ENWW

Step 5: Primary transfer

Photosensitive

drum

Primary transfer roller

ITB

Primary transfer bias

ITB

Paper

Secondary transfer roller

Secondary transfer bias

ITB

Paper

econdary transfer roller

econdary transfer bias

The positively-charged primary-transfer rollers contact the ITB, giving the ITB a positive charge. The ITB attracts the negatively-charged toner from the surface of each photosensitive drum, and the complete toner image transfers onto the ITB.

Figure 1-18 Primary transfer

Step 6: Secondary transfer

The paper acquires a positive charge from the secondary-transfer roller, and attracts the negatively-charged toner from the surface of the ITB. The complete toner image transfers onto the paper.

Figure 1-19 Secondary transfer

ENWW Engine laser/scanner system 37

Step 7: Separation

ITB

Paper

Secondary transfer roller

Static charge eliminator

ITB

Paper

econdary transfer roller

tatic charge eliminator

Paper

Fuser film

Fuser heater

Pressure roller

Fusing bias

The stiness 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 1-20 Separation

Step 8: Fusing

To create the permanent image, the paper passes through heated, pressurized rollers to melt the toner onto the page. Fusing bias is added to the pressure roller to improve the print quality.

Figure 1-21 Fusing

38 Chapter 1 Theory of operation ENWW

Step 9: ITB cleaning

Cleaning blade

Residual toner

Photosensitive

drum

The cleaning blade scrapes the residual toner o the surface of the ITB. The residual toner feed screw deposits residual toner in the toner collection unit. The residual toner which cannot be removed by the cleaning blade is charged by the ITB cleaning brush, and then transferred from the ITB surface to the photosensitive drum by the primary transfer (T1) roller.

Figure 1-22 ITB cleaning

Step 10: Drum cleaning

The cleaning blade scrapes the residual toner o the surface of the photosensitive drum, and toner is deposited in the toner collection portion of the cartridge.

Figure 1-23 Drum cleaning

ENWW Engine laser/scanner system 39

Toner cartridges

The printer has four toner cartridges, one for each color: cyan, magenta, yellow, and black.

Design

Each toner cartridge is lled with toner and consists of the following components:

●

Photosensitive drum

●

Developer roller

●

Primary-charging roller

●

Memory chip

The DC controller rotates the drum motor to drive the photosensitive drum, developer roller, and the primarycharging roller.

40 Chapter 1 Theory of operation ENWW

Figure 1-24 Toner cartridge system

M1/M2/M3

Drum motor

SR4

SR1/SR2/SR3

DC controller

Memory chip

Photosensitive drum

Developer

Primary charging

roller

Developer roller

Cartridge

Developer

disengagement

motor

Drum home position

sensor

Developing home position

sensor

ENWW Engine laser/scanner system 41

Memory chip

The memory chip is non-volatile memory that stores information about the usage of the toner cartridge and helps protect the customer from counterfeit cartridges. This chip is also used to detect the presence of a cartridge within the printer or when a cartridge is installed in the wrong slot. The printer reads and writes the data in the memory chip.

Toner seal

The toner cartridge seal is opened automatically when the toner cartridge is installed into the printer.

Toner level and cartridge life detection

Toner level detection: The DC controller detects the remaining toner in the cartridge by the optical detection

method and then noties the formatter of the remaining toner level.

Cartridge life detection: Cartridge life detection is measured in two ways.

1. Toner level:

●

For the rst 75% of cartridge life, toner level is measure through pixel counting by the DC controller. Once the level reaches 25%, the toner level sensor utilizes electrical properties to determine the amount of toner remaining.

2. Rotations of internal components (OPC and developer roller):

●

The DC controller monitors these two life parameters and reports them to the formatter as percent life remaining. End of cartridge life is determined by the lower value of the two.

Developing unit engagement and disengagement control

The printer can print in full-color mode or in black-only mode. To print in black-only mode, the printer disengages the developing rollers in the cyan, magenta, and yellow toner cartridges, which maximizes the life of the cartridges.

42 Chapter 1 Theory of operation ENWW

Figure 1-25 Developer roller engagement and disengagement control

Developing unit is disengaged

Developing disengagement motor

Photosensitive drum

Developing unit

Developing disengagement cam

SR4 Developing home position sensor

DC controller

Developing unit is engaged

The developer roller engagement and disengagement control operates as follows: When the printer is turned on and when each print job is completed, all four of the developing units are disengaged from the photosensitive drums.

●

The drive of the developer disengagement motor rotates the developer 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 blackonly, only the black developing unit engages with the drum.

The DC controller determines a developer disengagement motor failure and noties the formatter when it does not detect a specied signal from the developer disengagement sensor during the developing unit engagement and disengagement operation.

Cartridge Authentication Technology (CAT)

CAT supports two features for managing toner cartridges.

●

The authentication feature allows customers to specify the use of only genuine HP toner cartridges in the printer.

●

The anti-theft feature enables locking a cartridge to a specic printer or eet of printers.

ENWW Engine laser/scanner system 43

Authentication

The genuine HP authentication feature allows a customer to specify that only genuine HP supplies can be used in a printer. If a non-HP or used supply is installed, the printer will not print. This feature is disabled by default, and can be enabled or disabled from the control panel or the Embedded Web Server (EWS).

If a genuine HP toner cartridge from another printer is moved to a printer with this feature enabled, the toner cartridge will authenticate and print, unless the toner cartridge has passed the low state. If the toner cartridge has passed the low state, an Unauthorized Cartridge message displays on the control panel.

If a non-HP toner cartridge is used in a printer with this feature enabled, the message Unauthorized

Cartridge

NOTE: If a customer suspects they have a counterfeit cartridge, they should report it by going to www.hp.com/go/anticounterfeit and selecting Report now.

Anti-theft

The toner cartridge anti-theft feature allows a customer to congure the printer to automatically lock genuine HP toner cartridges to a specic printer or eet of printers when they are installed. A locked toner cartridge will only work in the specied printer or eet of printers. This feature prevents toner cartridges from being stolen and used in another printer, or from being moved from an authorized printer to an unauthorized printer. This feature is disabled by default, and can be enabled or disabled from the control panel, the Embedded Web Server (EWS), or Web Jetadmin.

When the anti-theft feature is enabled, the toner cartridge in a printer will only work in the specied printer or eet of printers. If a locked toner cartridge is moved to another printer, the cartridge will not print and the message Protected Cartridge appears on the control-panel display.

appears on the control-panel display.

NOTE: When a toner cartridge is locked to a specic printer or eet of printers, it cannot be unlocked. This is

a permanent operation.

44 Chapter 1 Theory of operation ENWW

Intermediate transfer belt (ITB) unit

ITB cleaner

ITB

Drum motor 3

SR5

SL1

Toner collection unit

Toner collection unit full

sensor

Fuser motor

Primary transfer roller

disengagement solenoid

ITB drive roller

Primary transfer roller

DC controller

ITB cleaner

ITB

Drum motor

Toner collection uni

Toner collection unit full

r motor

Primary transfer roller

disengagement solenoi

ITB drive roller

Primary transfer roller

DC controller

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:

●

Intermediate transfer belt (ITB)

●

ITB-drive roller

●

Primary-transfer roller

●

ITB cleaner

Drum motor 3 drives the ITB drive roller, which rotates the ITB. The motion of the ITB causes the primary transfer rollers to rotate. The ITB cleaner cleans the ITB surface.

Figure 1-26 ITB unit

Primary-transfer roller engagement and disengagement control

ENWW Engine laser/scanner system 45

Depending on the requirements of the print job, the primary-transfer rollers engage with the ITB so it can receive toner from the photosensitive drums. The primary-transfer rollers have three engagement states.

1-16 Primary-transfer roller engagement states

Table

All rollers disengaged The ITB is disengaged from all the four photosensitive drums. This state is the home

All rollers engaged The ITB is engaged with all four photosensitive drums. This is the state for full-color

Black roller engaged The ITB is engaged with only the black photosensitive drum. This is the state for black-

position for the ITB unit.

printing.

only printing.

Figure 1-27 Three states of primary-transfer roller engagement and disengagement

Four colors are disengaged

Four colors are engaged

Only black is engaged

Fuser motor

FUSER MOTOR CONTROL

SR5

The primary-transfer-roller disengagement motor rotates or reverses to place the primary-transfer-roller disengagement cam into one of three positions. The cam causes the transfer-roller slide plate to move to the right or left. This movement causes the primary-transfer rollers to move up to engage the ITB with the photosensitive drum or down to disengage it.

The DC controller expects to receive a signal from the ITB home-position sensor when the primary-transfer roller engages or disengages. If the DC controller does not receive this signal, but detects that the primarytransfer-roller disengagement motor is rotating, the DC controller determines that the primary-transferdisengagement mechanism has failed, and noties the formatter.

46 Chapter 1 Theory of operation ENWW

ITB unit detection

The DC controller monitors several signals from the ITB unit to detect status.

ITB unit life detection The DC controller detects whether the ITB unit is new by monitoring the new ITB

ITB unit presence detection The DC controller detects the presence of an ITB unit by monitoring the primary-

unit sensor. The DC controller determines the ITB unit is at end of life and noties the formatter when a specied number of pages are printed after the ITB unit is replaced. If swapping ITB units between two printers for troubleshooting purposes, be sure to return the ITB units to their original printers to maintain the correct life count.

NOTE: When installing a new ITB, refer to the instructions for resetting the ITB

life counter in the installation guide provided with the replacement part.

transfer roller disengagement sensor. The DC controller turns on the primarytransfer disengagement solenoid for specied times during an initial rotation period when the following events occur:

●

The printer is turned on

●

The printer exits sleep mode

●

The door is closed

The DC controller determines the absences of an ITB unit and noties the formatter when it does not detect a specied signal from the new primarytransfer roller disengagement sensor.

ENWW Engine laser/scanner system 47

ITB cleaning mechanism

The cleaning blade in the ITB cleaner scrapes the residual toner o the ITB surface and deposits the residual toner into the toner collection unit. 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 residual toner that cannot be removed by the cleaning blade is charged by the ITB cleaning brush, and then transferred from the ITB surface to the photosensitive drum by the primary transfer (T1) roller. The DC controller detects whether the toner collection unit is full by using the toner collection unit full sensor, and then noties the formatter.

Figure 1-28 ITB cleaning process

Secondary transfer roller functions

The secondary transfer roller transfers the image from the ITB onto the paper.

The printer has the following secondary transfer roller functions.

Table

1-17 Secondary transfer roller functions

Function Supported feature

Secondary transfer roller cleaning mechanism Yes

Secondary transfer roller presence detection No

Secondary transfer roller life detection No

Secondary transfer roller alienation control Yes

48 Chapter 1 Theory of operation ENWW

Calibration

The printer calibrates itself to maintain proper print quality. The calibration corrects color-misregistration and color-density variation due to environmental changes or internal variation in the printer.

The printer has the following calibration functions.

Table 1-18 Calibration functions

Function Supported feature

Color-plane registration correction control Yes

Environment correction control Yes

Image density control (DMAX) Yes

Image halftone control (DHALF) Yes

Registration density sensor failure detection Yes

Color sensor control No

Gray axis control (GAS) No

Environment sensor failure detection Yes

ENWW Engine laser/scanner system 49

Pickup, feed, and delivery system

Simplex paper path

Fuser-and-delivery block

Pickup-and-feed block

Duplex paper path

Duplex block

The DC controller controls the pickup, feed, and delivery system according to commands from the formatter. The pickup, feed, and delivery system uses a series of rollers to move the paper through the printer.

The pickup, feed, and delivery system consists of the following three functional blocks. The DC controller controls each block to pick up, feed and deliver the paper.

●

Pickup-and-feed-block: Controls the movement of the paper from each pickup source to the fuser inlet

●

Fuser-and-delivery-block: Controls the movement of the paper from the fuser to the delivery destination

●

Duplex block: Controls the movement of the paper from the duplex switchback unit to the duplex repickup unit (M552dn, M553dn, M553x, and M577 only)

Figure 1-29 Pickup, feed, and delivery system

50 Chapter 1 Theory of operation ENWW

Photo sensors and switches

SR8

SR6 (SR6N)

SR13 (SR13N) SR14 (SR14N)

SR12

SR9

PS1

SE1

SR10

SW5

The following gure shows the sensors and switches for the pickup, feed, and delivery system.

Figure 1-30 Photo sensors and switches

Table 1-19 Photo sensors and switches

Abbreviation Component Replacement part number

PS1 Loop sensor Fuser

SE1 Media sensor Registration assembly

SR6 Top-of-page (TOP) sensor (M552dn, M553dn, M553x,

and M577 only)

●

B5L35-67901 (110V)

●

B5L36-67901 (220V)

●

RM2-0093-000CN (M553n)

●

RM2-0018-000CN (M552dn, M553dn, M553x, M577)

Registration assembly (RM2-0018-000CN)

SR6N Top-of-page (TOP) sensor (M553n only) Registration assembly (RM2-0093-000CN)

SR8 Tray 1 media-out sensor Right door assembly (RM2-0019-000CN)

ENWW Pickup, feed, and delivery system 51

Table 1-19 Photo sensors and switches (continued)

Abbreviation Component Replacement part number

SR9 Fuser delivery sensor Fuser

●

B5L35-67901 (110V)

●

B5L36-67901 (220V)

SR10 Output bin media-full sensor Paper delivery assembly

●

RM2-0092-000CN (M553n)

●

RM2-0016-000CN (M552dn, M553dn, M553x, M577)

SR11 Fuser pressure release sensor Part not available

SR12 Tray 2 media-out sensor Paper pickup assembly (RM2-0017-000CN)

SR13 Media width sensor, front (M552dn, M553dn, M553x

and M577 only)

SR13N Media width sensor, front (M553n only) Registration assembly (RM2-0093-000CN)

SR14 Media width sensor, rear (M552dn, M553dn, M553x and

M577 only)

SR14N Media width sensor, rear (M553n only) Registration assembly (RM2-0093-000CN)

SW5 Tray 2 detection switch Part not available

Registration assembly (RM2-0018-000CN)

52 Chapter 1 Theory of operation ENWW

Motors, clutches, and solenoids

SL3

CL2M3SL2CL1

The following gure shows the motors, clutches, and solenoids for the pickup, feed, and delivery system.

Figure 1-31 Motors, clutches, and solenoids

Table 1-20 Motors, clutches, and solenoids

Abbreviation Component Replacement part number

M3 Drum motor 3 Drum motor assembly (RM2-0078-000CN)

M4 Fuser motor Fuser motor assembly (RM2-0077-000CN)

M5 Pickup motor Paper pickup drive assembly (RM2-0008-000CN)

M6 Developer disengagement motor Stepping motor (RK2-6027-000CN)

M7 Scanner motor Laser scanner assembly (RM2-0100-000CN)

M8 Duplex reverse motor (M552dn, M553dn, M553x, and

M577 only)

Duplexing drive assembly (RM2-0006-000CN)

ENWW Pickup, feed, and delivery system 53

Table 1-20 Motors, clutches, and solenoids (continued)

Abbreviation Component Replacement part number

CL1 Tray 2 pickup clutch Lifter drive assembly (RM2-0010-000CN)

CL2 Duplex re-pickup clutch (M552dn, M553dn, M553x, and

M577 only)

SL1 Primary transfer roller alienation solenoid Fuser drive assembly

SL2 Tray 1 pickup solenoid Right door assembly (RM2-0019-000CN)

SL3 Duplex reverse solenoid (M552dn, M553dn, M553x, and

M577 only)

Tray 1 (multipurpose)/Tray 2 (base printer)

Moving paper from Tray 1 and Tray 2 involves the interaction of multiple components within the printer. The following sections describe these processes.

Tray 1 paper pickup and feed

The printer picks up one sheet of paper from Tray 1.

Duplexing drive assembly (RM2-0006-000CN)

●

RM2-0091-000CN (M553n)

●

RM2-0009-000CN (M552dn, M553dn, M553x, M577)

Duplexing drive assembly (RM2-0006-000CN)

Following are the sequence of steps for the Tray 1 pickup operation.

NOTE: Tray 1 and Tray 2 are optimal for paper pickup when using special paper or media other than 20 lb

plain paper. For Tray 1, the printer increases the number of attempts to pick up a page, which increases the reliability of successfully picking the page from the tray and decreases the possibility of a mis-pick jam.

HP recommends using Tray 1 or Tray 2 if the printer is experiencing excessive or reoccurring jams from trays other than Tray 1 and Tray 2, or for print jobs that require media other than 20 lb plain paper.

1. The pickup motor reverses when a print command is received from the formatter.

2. When the DC controller turns on the Tray 1 pickup solenoid, the Tray 1 pickup roller rotates and the

lifting plate lifts.

3. As the lifting plate rises, the paper is picked up.

4. The Tray 1 separation pad removes any multiply-fed sheets, and one sheet is fed into the printer.

The Tray 1 media-out sensor (SR8) detects whether paper is present in Tray 1.

54 Chapter 1 Theory of operation ENWW

Figure 1-32 Tray 1 pickup mechanism

SR8

SL2

Tray 1 pickup solenoid

Tray 1 pickup roller

Tray 1 separation pad

Tray 2 paper presence detection

The Tray 2 media-out sensor (SR12) detects the presence of paper in Tray 2.

The DC controller noties the formatter when the Tray 2 media-out sensor detects that paper is absent.

Tray 2 lift operation

The printer keeps the paper stack surface at the correct pickup position. The Tray 2 lift-up operation is performed under the following conditions:

●

The printer is turned on

●

Tray 2 is installed

●

The paper stack surface in Tray 2 lowers

The operational sequence of the Tray 2 lift operation is as follows:

ENWW Pickup, feed, and delivery system 55

1. The pickup motor (M5) rotates and the lifter moves up. Note that this printer uses the pickup motor

rather than a dedicated lifter motor.

2. When the Tray 2 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 Tray 2 media stack surface sensor 1 detects the

stack surface and then lowers during printing.

When a Tray 2 media stack surface sensors does not detect the stack surface within a specied time period after the lifter motor starts rotating, the DC controller determines a lifter motor failure and noties the formatter.

Tray 2 paper pickup

Following are the sequence of steps for the Tray 2 pickup operation.

NOTE: Tray 1 and Tray 2 are optimal for paper pickup when using special paper or media other than 20 lb

1. The printer is turned on or Tray 2 is inserted.

2. The tray 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. The Tray 2 pickup roller and Tray 2 feed roller rotate.

5. The Tray 2 pickup solenoid turns on at a specied time.

6. The Tray 2 pickup cam rotates.

7. As the pickup arm lowers, the Tray 2 pickup roller touches the surface of the paper stack.

8. One sheet of paper feeds into the printer.

Tray 2 multiple-feed prevention

The printer uses a separation roller method to prevent multiple sheets of print media from entering the paper path.

The separation roller overruns if just one sheet of paper is picked. If two or more sheets are picked, only the top sheet will be fed to registration and the multiply-fed sheets will be held at the pickup location by the separation roller. This printer does not have an actively-driven separation roller.

56 Chapter 1 Theory of operation ENWW

Figure 1-33 Tray 2 multiple-feed prevention

Tray 2 separation roller follows the Tray 2 feed roller

Driving force from the pickup motor

Normal feed

Multiple feed

Paper

Tray 2 pickup roller

Tray 2 separation roller

Tray 1 feed roller

Tray 2 separation roller

llows the Tray 2 feed roller

Driving force from the pickup motor

Normal

feed

ultiple fee

Paper

Tray 2 pickup roller

Tray 2 separation roller

Tray 1 feed roller

Tray 2 presence detection

The Tray 2 presence sensor is in the lifter drive unit. The sensor detects the tray-presence sensor ag and determines whether the cassette is installed correctly.

Tray 2 skew feed prevention

The printer can straighten the paper without slowing the feed operation.

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 rotates, and the paper passes through

straightened.

ENWW Pickup, feed, and delivery system 57

Figure 1-34 Skew-feed prevention

Registration shutter

Paper

Registration shutter

Paper

Tray 2 media type detection

The printer selects the optimal print mode based upon the media type detected by the media sensor. The media sensor consists of an optical sensor, which detects the surface texture of the paper, and an ultrasonic sensor, which measures the thickness of the paper.

Following are the print modes detected by the printer:

●

Normal

●

Heavy media 1

●

Heavy media 2

●

Heavy media 3

58 Chapter 1 Theory of operation ENWW

●

Optical sensor

Ultrasonic sensor

Registration unit

Light media

●

Glossy media 1

●

Glossy media 2

●

Glossy media 3

●

LBP_OHT

The DC controller determines a media sensor error and reports it to the formatter when the value detected by the media sensor is out of a specied range of values.

Figure 1-35 Media sensors

Feed speed control

The DC controller adjusts the feed speed to improve the print quality depending on the paper type. The paper is fed at a specied speed according to the print mode designated by the formatter.

Table

1-21 Print mode and feed speed

Print mode

Normal 1/1 Yes

Heavy media 1 Pro No

Heavy media 2 1/2 Yes

Heavy media 3 1/3 Yes

Light media 1 1/1 Yes

Light media 2 1/1 Yes

Light media 3 1/3 Yes

Feed speed

ENWW Pickup, feed, and delivery system 59

Media sensor detection

Table 1-21 Print mode and feed speed (continued)

Print mode

Glossy media 1 1/3 Yes

Glossy media 2 1/3 Yes

Glossy media 3 1/3 Yes

Glossy lm 1/3 Yes

Envelope 1 1/2 No

OHT 1/3 Yes

Label 1/2 No

Designated media 1 1/2 No

Designated media 2 1/3 No

Designated media 3 Pro No

Speed for both full color and black and white pages 1/1 speed = 210 mm/s Pro speed = 174 mm/s 1/2 speed = 105 mm/s 1/3 speed = 70 mm/s

Feed speed

Media sensor detection

Duplexing unit (M552dn, M553dn, M553x, and M577 only)

The duplexing unit reverses the paper and feeds it through the paper path to print the second side.

Duplexing reverse and duplex feed control

The duplex reverse control reverses the paper after the rst side is printed and feeds it to the duplex repickup position to print the second side of the page.

1. At a specied time after the rst side of a page is printed, the duplex reverse motor rotates, and the

duplex reverse solenoid is turned on.

2. The duplex apper moves, and the paper feeds to the duplex reverse unit.

3. After a specied period of time, the duplex reverse motor reverses, and the paper feeds to the duplex

feed unit.

4. The duplex reverse motor and the pickup motor move the paper to the duplex re-pickup position.

5. The duplex reverse motor and the duplex feed clutch stop, and the paper feed operation pauses.

6. After a specied period of time, the duplex reverse motor rotates, and the duplex feed clutch is turned

on. The paper is then picked up again.

Jam detection/prevention

The printer 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.

●

Top of page (TOP) sensor (SR6/SR6N)

●

Media width sensor (front, SR13/SR13N)

60 Chapter 1 Theory of operation ENWW

●

SR6(SR6N)

SR13(SR13N) SR14(SR14N)

SR9

PS1

SR10

SR21

Media width sensor (rear, SR14/SR14N)

●

Loop sensor (PS1)

●

Fuser delivery sensor (SR9)

●

Output bin media-full sensor (SR10)

●

1x550 sheet paper feeder media feed sensor (SR21)

Figure 1-36 Jam detection sensors

The printer 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 noties the formatter.

1-22 Jams that the printer detects

Table

Jam Description

Media input delay jam 1 Media did not reach the registration sensor in time.

Media input delay jam 2 Media did not reach the source tray feed sensor in time.

Media input delay jam 3 Media did not reach the tray 3 feed sensor in time.

ENWW Pickup, feed, and delivery system 61

Table 1-22 Jams that the printer detects (continued)

Jam Description

Duplex re-feed jam 1 Media did not reach the registration sensor in time.

Media input stay jam 1 Media remained at the registration sensor longer than legal-sized media should remain.

Fuser delivery delay jam 1 Media did not reach the fuser output sensor in time.

Fuser delivery stay jam 1 Media stayed at fuser output sensor longer than it should stay. Media is in duplex path.

Fuser delivery stay jam 2 Media stayed at fuser output sensor longer than it should stay. Media is in simplex path.

Wrap jam 1 Media is rst detected at fuser output sensor and then disappeared from the sensor before it should

have disappeared.

Door open jam A door is open while paper is moving through the printer.

Residual Media in paper path jam 1

Fuser wrapping jam detection

The printer includes controls for detecting when a jam occurs causing the paper to wrap around the fuser roller.

Loop control

The loop control stabilizes the paper feed operation before the paper enters the fuser. If the pressure roller rotates slower than the secondary transfer roller, the paper loop increases and an image defect or paper crease occurs. If the pressure roller rotates faster than the secondary transfer roller, the paper loop decreases and a vertical scanning magnication failure occurs because the pressure roller pulls the paper.

To prevent these problems, the loop sensor detects 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 sensor and maintains the paper loop. The DC controller slows the fuser motor when the sensor is o and speeds up the motor when the sensor is on.

Media detected in the paper path.

62 Chapter 1 Theory of operation ENWW

Figure 1-37 Loop control mechanism

The pressure roller rotates faster than the secondary transfer roller

Loop sensor: OFF

ITB

Loop sensor

Secondary transfer rollerr

Pressure roller

Sensor flag

Loop sensor: ON

The pressure roller rotates slower than the secondary transfer roller

SR11 SR11

Pressure roller

DC controller

Fuser pressure release cam

Fuser motor

Pressurized Depressurized

Fuser sleeve

Pressure roller pressurization and depressurization control

To prevent excessive wear on the pressure roller and help with jam-clearing procedures, the pressure roller pressurizes only during printing and standby. The DC controller reverses the fuser motor. The fuser motor rotates the fuser pressure-release cam.

Figure 1-38 Pressure roller pressurization control

The pressure roller depressurizes under the following conditions:

ENWW Pickup, feed, and delivery system 63

●

The printer is turned o

●

Any failure occurs

●

During power-save mode

●

A paper jam is detected

If the DC controller does not sense the fuser pressure-release sensor for a specied period after it reverses the fuser motor, it noties the formatter that a fuser pressure-release mechanism failure has occurred.

64 Chapter 1 Theory of operation ENWW

Input accessories

NOTE: An optional 550-sheet paper feeder is available for this printer. The printer supports up to three of

these paper feeders at a time.

Trays 3-5

The 550-sheet paper feeder is installed under the printer. It picks up paper and feeds it into the printer.

Figure 1-39 550-sheet paper feeder

Trays 3-5 driver PCA

The paper feeder controller controls the operational sequence of the paper feeder.

ENWW Input accessories 65

Figure 1-40 Tray 3-5 driver PCA

+24V

+3.3V

DC controller

Paper feeder controller

Motor

Photointerruptor

Clutch

Switch

550-sheet paper feeder

Trays 3-5 motor control

The 550-sheet paper feeder has one motor for lifting the tray and feeding paper.

Table 1-23 Trays 3-5 motor control

Component Drives Failure

detection

Trays 3-5 electrical components

M20 Feed motor (550-sheet paper

feeder)

Tray pickup roller (B5L24-67904)

Tray feed roller (B5L24-67904)

Paper feed assembly (RM2-5145-000CN)

Lifter drive assembly (RM2-5149-000CN)

The paper feeder contains several motors, solenoids, sensors, and switches, as described in the following table.

Table

1-24 Tray 3-5 electrical components

Component type Abbreviation Component name Replacement part number

Motor M20 Feed motor (550-sheet paper feeder) Paper feed assembly

(RM2-5145-000CN)

Clutch CL20 Tray pick up clutch (550-sheet paper

feeder)

Switches SW20 Right door switch (550-sheet paper

feeder)

Sensors SR20 Tray media-out sensor (550-sheet

SW21 Tray detection switch (550-sheet paper

feeder)

paper feeder)

Lifter drive assembly (RM2-5149-000CN)

Right door (RM2-5146-000CN)

Switch button (WC2-5806-000CN)

Paper pick up assembly (RM2-5154-000CN)

66 Chapter 1 Theory of operation ENWW

Table 1-24 Tray 3-5 electrical components (continued)

M20

CL20

SR21

SW21

SR20

Component type Abbreviation Component name Replacement part number

Trays 3-5 paper pickup

The 550-sheet paper feeder picks up one sheet from the paper-feeder tray and feeds it to the printer.

Figure 1-41 Paper pickup and feed operation (550-sheet paper feeder)

SR21 Feed sensor (550-sheet paper feeder) Paper feed assembly

(RM2-5145-000CN)

Table 1-25 Pickup feed components (1x550-sheet paper feeder)

Abbreviation Component Replacement part number

M20 Feed motor (550-sheet paper feeder) Paper feed assembly (RM2-5145-000CN)

CL20 Tray pickup clutch (550-sheet paper feeder) Part not available

SR20 Tray media-out sensor (550-sheet paper feeder) Paper pick up assembly (RM2-5154-000CN)

SR21 Feed sensor (550-sheet paper feeder) Paper feed assembly (RM2-5145-000CN)

SW21 Tray detection switch (550-sheet paper feeder) Switch button (WC2-5806-000CN)

Trays 3-5 multiple feed prevention

The multiple-feed prevention for the 550-sheet paper feeder is operated in the same way as that of the printer base.

Trays 3-5 tray presence detection

The presence detection for the 550-sheet paper feeder is the same way as that of the printer base.

ENWW Input accessories 67

Trays 3-5 tray lift operation

The 550-sheet paper feeder keeps the paper stack surface at the correct pickup position. The tray lift operation occurs under the following conditions:

●

The printer is turned on.

●

The tray is inserted.

●

The paper stack surface of the tray lowers.

The sequence occurs as follows:

1. The feeder tray-lifting motor rotates and the lifter moves up.

2. When the paper-feeder media-stack-surface sensor detects the stack surface of the paper, the lifting

motor stops.

3. The lifting motor rotates again to lift the lifter when the paper-feeder media-stack-surface sensor

detects the stack surface, and then lowers during printing.

If a tray media-stack-surface sensor does not detect a stack surface within a specied period after the lifting motor starts rotating, the paper feeder driver determines that the lifting motor has failed and noties the formatter through the DC controller.

The paper-feeder driver noties the formatter if either of the paper-feeder media-stack-surface sensors fails to detect the stack surface within a specied period from when a lift-up operation starts.

68 Chapter 1 Theory of operation ENWW

Trays 3-5 jam detection

SR21

SW20

The 550-sheet paper feeder uses the feed sensor (SR21) and right door switch (SW20) to detect the presence of paper and to check whether paper has jammed.

Figure 1-42 Jam detection (1x550-sheet paper feeder)

The 550-sheet paper feeder detects the following jams:

●

Media input delay jam 1 (550-sheet paper feeder): Paper did not reach the registration sensor in time.

●

Media input delay jam 2 (550-sheet paper feeder): Paper did not reach the source tray feed sensor in time.

●

Media input delay jam 3 (550-sheet paper feeder): Paper did not reach the tray 3 feed sensor in time.

●

Pickup stationary jam (550-sheet paper feeder): The feed sensor does not detect the trailing edge of paper within a specied time after the sensor detects the leading edge.

●

Residual paper jam (550-sheet paper feeder): The feed sensor detects the presence of paper for a

specied time during an automatic delivery operation.

●

Right door open jam (550-sheet paper feeder): The right door open is detected during a paper feed operation.

ENWW Input accessories 69

Scanning and image capture system (M577)

NOTE: This section is for the M577 printer only.

The scanner is a carriage-type platen scanner which includes the frame, glass, scan module, and a scan control board (SCB). The scanner has a sensor to detect legal-sized media and a switch to indicate when the document feeder is opened.

The document feeder and control panel are attached to the scanner. If the scanner fails, it can be replaced as a whole unit. The scanner replacement part does not include the document feeder, control panel, or SCB.

70 Chapter 1 Theory of operation ENWW

Document feeder system (M577)

NOTE: This section is for the M577 printer only.

Document feed system

This section describes the following:

●

Sensors in the document feeder

●

Document feeder paper path

●

Simplex single-pass scanning

●

Electronic duplexing (e-duplex) single-pass scanning

●

Deskew operation

●

Document feeder hinges

The printer supports single-pass electronic duplexing (e-duplex) copy jobs. Two separate scan modules scan the front-side and back-side of an e-duplex copy job page in a single pass through the document feeder.

For the M577c/z models, the document feeder supports a smart background, which auto-crops and adjusts the image extents.

Sensors in the document feeder

The document feeder contains the following sensors:

●

ADF paper present sensor: Detects whether a document is present in the document feeder. If paper is present in the document feeder when copies are made, the printer scans the document using the document feeder. If no paper is present when copies are made, the printer scans the document using the scanner glass.

●

ADF Y (length) sensor: Detects whether a legal-size original is present in the document feeder.

●

ADF jam cover sensor: Detects whether the document feeder cover is open or closed.

●

ADF paper path deskew sensor: Detects the top of the page as it enters the deskew rollers.

●

ADF paper path pick success sensor: Detects a successful one page feed from the document feeder tray.

NOTE: This sensor uses ultrasonic sound to detect a multi-page paper feed.

●

Paper path sensor 1: Detects the top of the page as it approaches the front-side scan module (document feeder glass).

ENWW Document feeder system (M577) 71

Figure 1-43 Document feeder sensors

Table 1-26 Document feeder sensors

Item Description

1 ADF Y (length) sensor

2 ADF paper present sensor

3 ADF deskew sensor

4 Paper path sensor 1

NOTE: For an e-duplex copy job, this sensor is used to activate the front-side scan module (in the

scanner base) and the front-side background selector (in the document feeder), if needed.

5 ADF jam cover sensor (open the jam access cover and insert a folded piece of paper to activate the ag)

Document feeder paper path

Figure 1-44 Document feeder paper path

Table

1-27 Document feeder paper path

Item Description Item Description

1 Input tray 7 Front-side scan module

NOTE: This scan module (document feeder glass) is

located in the scanner base.

2 Pre-pick roller 8 Back-side scan module

72 Chapter 1 Theory of operation ENWW

HP m552, m553, m577 Troubleshooting Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Theory of operation

For additional service and support

Basic operation

Sequence of operation

Formatter-control system

Sleep mode

Printer job language (PJL)

Printer management language (PML)

Control panel

Easy-access USB port

Wireless

Input/output (I/O)

Memory

Firmware

Nonvolatile random access memory (NVRAM)

Random access memory (RAM)

HP Memory Enhancement technology (MEt)

Engine-control system

DC controller

Motors

Fans

Solenoids

Clutches

Switches

Sensors

Low-voltage power supply

Low-voltage power supply voltages description

Over-current/over-voltage protection

Sleep mode operation

Low-voltage power supply failure detection

Low-voltage power supply functions

High-voltage power supply

High-voltage power supply circuits

Fuser bias

Fuser control

Fuser circuits

Fuser control functions

Fuser temperature control

Fuser heater protection

Fuser unit life detection

Engine laser/scanner system

Laser/scanner failure detection

Safety

Image-formation process

Step 1: Pre-exposure

Step 2: Primary charging

Step 3: Laser-beam exposure

Step 4: Development

Step 5: Primary transfer

Step 6: Secondary transfer

Step 7: Separation

Step 8: Fusing

Step 9: ITB cleaning

Step 10: Drum cleaning

Toner cartridges

Design

Memory chip

Toner seal

Toner level and cartridge life detection

Developing unit engagement and disengagement control

Cartridge Authentication Technology (CAT)

Authentication

Anti-theft

Intermediate transfer belt (ITB) unit

Primary-transfer roller engagement and disengagement control

ITB unit detection

ITB cleaning mechanism

Secondary transfer roller functions

Calibration

Pickup, feed, and delivery system

Photo sensors and switches

Motors, clutches, and solenoids

Tray 1 (multipurpose)/Tray 2 (base printer)

Tray 1 paper pickup and feed

Tray 2 paper presence detection

Tray 2 lift operation