HP Color LaserJet Enterprise CP4025, Color LaserJet Enterprise CP4525 Service Manual

COLOR LASERJET ENTERPRISE CP4020/CP4520

SERIES PRINTER

Service Manual

CP4025n

CP4025dn

CP4525n

CP4525dn

CP4525xh

Copyright and License

© 2009 Copyright Hewlett-Packard

Development Company, L.P.

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

The information contained herein is subject to change without notice.

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

Part number: CC489-90936

Edition 1, 10/2009

Trademark Credits

Adobe®, Acrobat®, and PostScript® are trademarks of Adobe Systems Incorporated.

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

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

Java™ is a US trademark of Sun

Microsystems, Inc.

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

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

UNIX® is a registered trademark of The Open Group.

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

Conventions used in this guide

TIP: Tips provide helpful hints or shortcuts.

NOTE: Notes provide important information to explain a concept or to complete a task.

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

WARNING! Warnings alert you to specific procedures that you should follow to avoid personal injury, catastrophic loss of data, or extensive damage to the product.

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Table of contents

1 Theory of operation
Basic operation .....................................................................................................................................	2
Sequence of operation .........................................................................................................	3
Engine-control system ..........................................................................................................................	4
DC controller ........................................................................................................................	5
Solenoids ............................................................................................................	5
Clutches ..............................................................................................................	6
Switches ..............................................................................................................	6
Sensors ...............................................................................................................	7
Motors .................................................................................................................	8
Fans .....................................................................................................................................	9
High-voltage power supply ................................................................................................	10
Low-voltage power supply .................................................................................................	12
Overcurrent/overvoltage protection ...................................................................	13
Safety ................................................................................................................	13
Voltage detection ..............................................................................................	13
Sleep (powersave) mode ..................................................................................	13
Low-voltage power supply failure ......................................................................	13
Fuser control ......................................................................................................................	14
Fuser temperature control .................................................................................	15
Fuser sleeve temperature protection ................................................................	15
Failure detection ................................................................................................	16
Fuser unit identification .....................................................................................	17
Fuser unit life detection .....................................................................................	17
Laser/scanner system ........................................................................................................................	18
Laser/scanner failure .........................................................................................................	19
Protective-glass cleaners ...................................................................................................	19
Image-formation system .....................................................................................................................	21
Image-formation process ...................................................................................................	22
Step 1: Pre-exposure ........................................................................................	24
Step 2: Primary charging ...................................................................................	24
Step 3: Laser-beam exposure ...........................................................................	25
Step 4: Development .........................................................................................	25
Step 5: Primary transfer ....................................................................................	26

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Step 6: Secondary transfer ...............................................................................	26
Step 7: Separation ............................................................................................	27
Step 8: Fusing ...................................................................................................	27
Step 9: ITB cleaning ..........................................................................................	28
Step 10: Drum cleaning .....................................................................................	28
Print cartridge ....................................................................................................................	28
Developing-roller engagement and disengagement ..........................................................	30
Intermediate transfer belt (ITB) unit ...................................................................................	31
Primary-transfer-roller engagement and disengagement ..................................	32
ITB cleaning ......................................................................................................	34
Calibration ..........................................................................................................................	34
Color-misregistration control .............................................................................	35
Image-stabilization control ................................................................................	35
Pickup, feed, and delivery system ......................................................................................................	37
Pickup-and-feed unit ..........................................................................................................	41
Cassette pickup .................................................................................................	41
Cassette-presence detection ............................................................	42
Cassette lift operation and cassette paper-presence detection ........	43
Cassette multiple-feed prevention ....................................................	43
Multipurpose tray pickup ...................................................................................	44
Paper feed .........................................................................................................	45
Skew-feed prevention .......................................................................	46
Paper detection ................................................................................	47
Feed speed control ...........................................................................	48
Fusing and delivery unit .....................................................................................................	48
Loop control ......................................................................................................	49
Pressure-roller pressurization control ...............................................................	50
Duplexing unit (HP Color LaserJet CP4525dn, HP Color LaserJet CP4025dn, and HP
Color LaserJet CP4525xh only) .........................................................................................	52
Duplexing reverse and feed control ..................................................................	52
Duplex print operation .......................................................................................	53
Jam detection .....................................................................................................................................	55
Optional paper feeder .........................................................................................................................	57
Motor control ......................................................................................................................	59
Paper-feeder pickup and feed operation ...........................................................................	60
Paper-size detection and cassette-presence detection .....................................................	62
Paper-feeder cassette lift operation ...................................................................................	63
Paper feeder jam detection ................................................................................................	64
2 Removal and replacement
Introduction .........................................................................................................................................	68
Removal and replacement strategy ...................................................................................................	68
Electrostatic discharge .......................................................................................................................	69
Required tools ...................................................................................................................................	69

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Before performing service ..................................................................................................................	70
After performing service .....................................................................................................................	70
Post-service test .................................................................................................................................	71
Print-quality test .................................................................................................................	71
Parts removal order ............................................................................................................................	72
Customer self repair (CSR) components ...........................................................................................	74
Print cartridges ...................................................................................................................	74
Toner-collection unit ..........................................................................................................	76
Formatter PCA ...................................................................................................................	78
Hard drive ..........................................................................................................................	79
Remove the hard drive ......................................................................................	79
Memory DIMM ...................................................................................................................	81
Remove the memory DIMM ..............................................................................	81
Enable memory ................................................................................	82
Tray ....................................................................................................................................	84
Fuser .................................................................................................................................	85
Feed and separation rollers (Trays 2-5) ............................................................................	86
Pickup roller (Tray 1) .........................................................................................................	87
Secondary transfer roller ...................................................................................................	90
Reinstall the transfer roller ................................................................................	91
Intermediate transfer belt (ITB) ..........................................................................................	92
External panels, covers, and doors ....................................................................................................	95
Identification and location ..................................................................................................	95
Upper-left cover .................................................................................................................	96
Power-supply cover ...........................................................................................................	98
Left cover ...........................................................................................................................	99
Remove the left cover .......................................................................................	99
Front-top cover ................................................................................................................	100
Remove the front-top cover .............................................................................	100
Rear-top cover .................................................................................................................	102
Remove the rear-top cover .............................................................................	102
Right-front cover ..............................................................................................................	103
Remove the right-front cover ...........................................................................	103
Reinstall the power button ..............................................................	104
Control-panel assembly ...................................................................................................	105
Remove the control-panel assembly ...............................................................	105
Front-door assembly ........................................................................................................	107
Remove the front-door assembly ....................................................................	107
Right-rear cover ...............................................................................................................	110
Remove the right-rear cover ...........................................................................	110
Rear cover .......................................................................................................................	112
Remove the rear cover ...................................................................................	112
Right-door assembly ........................................................................................................	113
Internal assemblies ..........................................................................................................................	118

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Cassette feed guide .........................................................................................................	118
Secondary transfer assembly ..........................................................................................	119
Reinstall the secondary transfer assembly .....................................................	120
Separation pad (Tray 1) ...................................................................................................	121
Remove the separation pad (Tray 1) ..............................................................	121
Registration density (RD) sensor assembly .....................................................................	124
Remove the RD sensor assembly ...................................................................	124
Registration assembly .....................................................................................................	128
Remove the registration assembly ..................................................................	129
Residual-toner-feed motor ...............................................................................................	133
Remove the residual-toner-feed motor ...........................................................	133
Residual-toner duct and feed assembly ..........................................................................	134
Remove the residual-toner duct and feed assembly .......................................	134
Cartridge fan and environmental sensor ..........................................................................	137
Remove the cartridge fan and environmental sensor .....................................	137
Toner-collection sensor and scanner-thermistor assembly .............................................	141
Remove the toner-collection sensor and scanner-thermistor assembly .........	141
Delivery fan ......................................................................................................................	143
Remove the delivery fan .................................................................................	143
Delivery assembly ............................................................................................................	145
Remove the delivery assembly .......................................................................	145
Reinstall the delivery assembly ......................................................	149
Duplex-drive assembly ....................................................................................................	151
Remove the duplex-drive assembly ................................................................	151
Power-supply fan .............................................................................................................	152
Remove the power-supply fan ........................................................................	152
Interconnect board (ICB) .................................................................................................	153
Remove the ICB ..............................................................................................	153
DC controller PCA only ....................................................................................................	155
Remove the DC controller PCA only ...............................................................	155
Low-voltage power supply (LVPS) ...................................................................................	157
Remove the low-voltage power supply ...........................................................	157
DC controller PCA and tray .............................................................................................	161
Remove the DC controller PCA and tray ........................................................	161
High-voltage power supply lower (HVPS-D) ....................................................................	163
Remove the high-voltage power supply lower ................................................	163
Reinstall the high-voltage power supply lower ...............................	167
Developing-disengagement motor ...................................................................................	168
Remove the developing-disengagement motor ..............................................	168
Exhaust fan and fan duct .................................................................................................	169
Remove the exhaust fan and fan duct ............................................................	169
Reinstall the exhaust fan and fan duct ............................................................	171
Pickup motor ....................................................................................................................	172
Remove the pickup motor ...............................................................................	172

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Lifter-drive assembly ........................................................................................................	173
Remove the lifter-drive assembly ....................................................................	173
Lifter base assembly ........................................................................................................	175
Remove the lifter base assembly ....................................................................	175
Reinstall the lifter base assembly ....................................................................	176
Tray-pickup drive assembly .............................................................................................	178
Remove the tray-pickup drive assembly .........................................................	178
Tray-pickup assembly ......................................................................................................	180
Remove the tray-pickup assembly ..................................................................	180
Laser/scanner assembly (Y/M) ........................................................................................	186
Remove the laser/scanner assembly (Y/M) ....................................................	187
Laser/scanner assembly (C/Bk) .......................................................................................	190
Remove the laser/scanner assembly (C/Bk) ...................................................	191
Reinstall the protective glass cleaner (PGC) actuators ..................	193
High-voltage power supply upper (HVPS-T) ....................................................................	196
Remove the high-voltage power supply upper ................................................	196
Reinstall the high-voltage power supply upper ...............................	198
Yellow, magenta, cyan, and black drum motors ..............................................................	199
Remove the yellow, magenta, cyan, and black drum motors ..........................	199
Fuser motor .....................................................................................................................	200
Remove the fuser motor ..................................................................................	201
ITB motor .........................................................................................................................	202
Remove the ITB motor ....................................................................................	202
Main-drive assembly ........................................................................................................	203
Remove the main-drive assembly ...................................................................	204
Reinstall the main-drive assembly ..................................................	207
Fuser-drive assembly ......................................................................................................	211
Remove the fuser-drive assembly ...................................................................	212
Reinstall the fuser-drive assembly ..................................................	215
Optional paper feeder assemblies (1 x 500-sheet and 3 x 500-sheet) .............................................	216
Front door (optional paper feeder) ...................................................................................	216
Rear cover (optional paper feeder) ..................................................................................	218
Right-front cover (optional paper feeder) .........................................................................	219
Right door (optional paper feeder) ...................................................................................	220
Left cover (optional paper feeder) ....................................................................................	222
Remove the left cover (optional paper feeder) ................................................	222
Right cover (optional paper feeder) .................................................................................	224
Remove the right cover (optional paper feeder) ..............................................	224
Rear-right cover (optional paper feeder) ..........................................................................	225
Remove the rear-right cover (optional paper feeder) ......................................	225
Pickup assembly (optional paper feeder) ........................................................................	226
Remove the pickup assembly (optional paper feeder) ....................................	226
Lifter assembly (optional paper feeder) ...........................................................................	229
Remove the lifter assembly (optional paper feeder) .......................................	229

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Lifter-drive assembly (optional paper feeder) ..................................................................	230
Remove the lifter-drive assembly (optional paper feeder) ..............................	230
Pickup motor assembly (optional paper feeder) .............................................................	231
Remove the pickup motor (optional paper feeder) assembly ..........................	231
Controller PCA (optional paper feeder) ...........................................................................	232
Remove the controller PCA (optional paper feeder) .......................................	232
3 Solve problems
Solve problems checklist ..................................................................................................................	234
Menu map ........................................................................................................................................	236
Troubleshooting process ..................................................................................................................	237
Determine the problem source ........................................................................................	237
Pre-troubleshooting checklist ..........................................................................	237
Troubleshooting flowchart ...............................................................................	239
Power subsystem ............................................................................................................	240
Power-on checks .............................................................................................	240
Power-on troubleshooting overview ...............................................	240
Tools for troubleshooting ..................................................................................................................	242
Individual component diagnostics ....................................................................................	242
LED diagnostics ..............................................................................................	242
Understand lights on the formatter .................................................	242
Engine diagnostics ..........................................................................................	243
Defeating interlocks ........................................................................	243
Disable cartridge check ..................................................................	244
Engine-test button ..........................................................................	244
Paper-path test ................................................................................................	245
Manual sensor test (special-mode test) ..........................................................	246
A TOP (top of page) sensor ............................................................	247
B and C loop sensors .....................................................................	248
D fuser delivery sensor ...................................................................	249
E duplex re-pickup sensor ..............................................................	250
F output bin full sensor ...................................................................	251
I developer alienation .....................................................................	252
J fuser pressure-release sensor ....................................................	253
K primary transfer-roller-disengagement sensor ............................	254
L media sensor ..............................................................................	256
M front-door switch .........................................................................	257
N right-door switch ..........................................................................	258
Manual sensor test 2 (special-mode test) .......................................................	259
O Tray 1 paper present sensor ......................................................	261
P Tray 2 paper present sensor .......................................................	262
Q Tray 2 paper surface 1 and 2 sensors ........................................	263
R Tray 2 paper size switches ........................................................	264

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S Tray 3 paper present sensor .......................................................	265
T Tray 3 feed sensor ......................................................................	265
U Tray 3 paper surface 1 and 2 sensors ........................................	265
V Tray 3 paper size switches ..........................................................	265
W Tray 4 paper present sensor ......................................................	265
X Tray 4 feed sensor ......................................................................	265
Y Tray 4 paper surface 1 and 2 sensors ........................................	265
Z Tray 4 paper size switches ..........................................................	266
a Tray 5 paper present sensor .......................................................	266
b Tray 5 feed sensor .......................................................................	266
c Tray 5 paper surface 1 and 2 sensors .........................................	266
d Tray 5 paper size switches ..........................................................	266
5V laser and 24V interlock and logic switches (and power
switch) ............................................................................................	267
New ITB sensor ..............................................................................	271
Tray 3, 4, and 5 right door switch ...................................................	272
Paper-path sensors test ..................................................................................	273
Print/stop test ..................................................................................................	273
Component tests .............................................................................................	274
Component test (special-mode test) ...............................................	274
Diagrams .........................................................................................................................	277
Block diagrams ................................................................................................	277
Plug/jack locations ..........................................................................................	280
Location of connectors ....................................................................................	281
DC controller connector locations ...................................................	281
Controller PCA (1 x 500-sheet and 3 x 500-sheet optional paper
feeders) .........................................................................................	283
Locations of major components ......................................................................	284
General timing chart ........................................................................................	294
Circuit diagrams ..............................................................................................	294
HP Easy Printer Care ......................................................................................................	298
Open the HP Easy Printer Care software .......................................................	299
HP Easy Printer Care software sections .........................................................	299
Internal print-quality test pages ........................................................................................	302
Print-quality-troubleshooting pages .................................................................	302
Diagnostics page .............................................................................................	305
Cleaning page .................................................................................................	306
Configuration page ..........................................................................................	307
Configuration page .........................................................................	307
HP embedded Jetdirect page .........................................................	309
Embedded protocol page ...............................................................	310
Finding important information on the configuration pages ..............	311
Color-band test ................................................................................................	311
Print-quality troubleshooting tools ....................................................................................	312

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Repetitive defects ruler ...................................................................................	312
Calibrate the product .......................................................................................	313
Control panel menus ........................................................................................................	314
Control panel menus .......................................................................................	314
Show Me How menu ......................................................................	314
Retrieve job menu ..........................................................................	314
Information menu ............................................................................	317
Paper handling menu .....................................................................	317
Manage supplies menu ..................................................................	318
Configure device menu ...................................................................	321
Diagnostics menu ...........................................................................	342
Service menu ..................................................................................	344
Interpret control-panel messages ....................................................................................	345
Control-panel message types .........................................................................	345
Control-panel messages .................................................................................	345
Event log messages ........................................................................................................	376
Print an event log ............................................................................................	376
Show an event log ...........................................................................................	376
Sample event log ............................................................................................	377
Clear the event log ..........................................................................................	377
Event log message table .................................................................................	378
Clear paper jams ..............................................................................................................................	383
Common causes of jams .................................................................................................	383
Jam locations ...................................................................................................................	386
Clear jams in the right door ..............................................................................................	387
Clear jams in the output bin area .....................................................................................	390
Clear jams in Tray 1 .........................................................................................................	390
Clear jams in Tray 2 or optional Trays 3, 4, or 5 ..............................................................	392
Clear jams in the lower right door (Tray 3, 4, or 5) ..........................................................	393
Jam causes and solutions ...............................................................................................	394
Jams in the output bin .....................................................................................	394
Jams in the fuser and transfer area ................................................................	394
Jams in the duplex area (HP Color LaserJet CP4525dn, HP Color LaserJet
CP4025dn, and HP Color LaserJet CP4525xh only) ......................................	397
Jams in Tray 1, Tray 2 and internal paper path ..............................................	399
Jams in Tray 3, 4, and 5 ..................................................................................	400
Change jam recovery .......................................................................................................	402
Solve paper-handling problems ........................................................................................................	403
Product feeds multiple sheets ..........................................................................................	403
Product feeds incorrect page size ...................................................................................	403
Product pulls from incorrect tray ......................................................................................	403
Paper does not feed automatically ..................................................................................	404
Paper does not feed from Tray 2, 3, 4, or 5 .....................................................................	404
Transparencies or glossy paper will not feed ..................................................................	405

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Envelopes jam or will not feed in the product ..................................................................	405
Output is curled or wrinkled .............................................................................................	406
Product will not duplex or duplexes incorrectly ................................................................	406
Use manual print modes ..................................................................................................................	408
Solve image-quality problems ..........................................................................................................	410
Image defects table .........................................................................................................	410
Clean the product .............................................................................................................................	416
Clean the paper path .......................................................................................................	416
Solve performance problems ...........................................................................................................	417
Solve connectivity problems .............................................................................................................	418
Solve direct-connect problems ........................................................................................	418
Solve network problems ..................................................................................................	418
Service mode functions ....................................................................................................................	420
Service menu ...................................................................................................................	420
Product resets ..................................................................................................................	423
Restore factory-set defaults ............................................................................	423
Hard disk initialization (optional) .....................................................................	423
NVRAM initialization ........................................................................................	423
Product cold reset ..........................................................................................	424
Product updates ...............................................................................................................................	424
4 Parts and diagrams
Order parts, accessories, and supplies ............................................................................................	426
Part numbers ....................................................................................................................................	427
Accessories .....................................................................................................................	427
Print cartridges and toner collection unit ..........................................................................	427
Memory ............................................................................................................................	427
Cables and interfaces ......................................................................................................	427
Customer self repair (CSR) parts ....................................................................................	428
Service maintenance kits .................................................................................................	428
Unique components .........................................................................................................	429
Screws ..............................................................................................................................................	430
How to use the parts lists and diagrams ..........................................................................................	431
External covers, panels, and doors ..................................................................................................	432
Right door assembly .........................................................................................................................	434
Front door assembly .........................................................................................................................	436
Internal components .........................................................................................................................	438
Internal components (1 of 7) ............................................................................................	438
Internal components (2 of 7) ............................................................................................	440
Internal components (3 of 7) ............................................................................................	442
Internal components (4 of 7) ............................................................................................	444
Internal components (5 of 7) ............................................................................................	446
Internal components (6 of 7) ............................................................................................	448

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Internal components (7 of 7) ............................................................................................	450
Cassettes 2-5 ...................................................................................................................	452
Paper pickup assembly ....................................................................................................	454
Tray 1 paper pickup assembly .........................................................................................	456
Registration assembly .....................................................................................................	458
Secondary transfer assembly ..........................................................................................	460
Delivery assembly ............................................................................................................	462
Fuser assembly ...............................................................................................................	464
PCAs ................................................................................................................................	466
Assessories ......................................................................................................................................	468
Paper feeders ..................................................................................................................	468
Paper feeder external covers, panels, and doors ............................................................	470
1 X 500 paper feeder main body .....................................................................................	472
3 X 500 paper feeder main body .....................................................................................	474
Alphabetical parts list .......................................................................................................................	476
Numerical parts list ...........................................................................................................................	484
Appendix A Service and support
Hewlett-Packard limited warranty statement ....................................................................................	494
HP's Premium Protection Warranty: LaserJet print cartridge limited warranty statement ................	495
HP Color LaserJet Fuser Kit Limited Warranty Statement ...............................................................	496
End User License Agreement ..........................................................................................................	497
Customer self-repair warranty service ..............................................................................................	499
Customer support .............................................................................................................................	500
Appendix B Product specifications
Physical specifications .....................................................................................................................	502
Performance specifications ..............................................................................................................	502
Electrical specifications ....................................................................................................................	502
Acoustic specifications .....................................................................................................................	503
Environmental specifications ............................................................................................................	503
Skew specifications ..........................................................................................................................	504
Appendix C Regulatory information
FCC regulations ...............................................................................................................................	506
Environmental product stewardship program ...................................................................................	507
Protecting the environment ..............................................................................................	507
Ozone production ............................................................................................................	507
Power consumption .........................................................................................................	507
Toner consumption ..........................................................................................................	507
Paper use ........................................................................................................................	507
Plastics ............................................................................................................................	507
HP LaserJet print supplies ...............................................................................................	507

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Return and recycling instructions .....................................................................................	508
United States and Puerto Rico ........................................................................	508
Multiple returns (more than one cartridge) .....................................	508
Single returns .................................................................................	508
Shipping ..........................................................................................	508
Non-U.S. returns .............................................................................................	508
Paper ...............................................................................................................................	508
Material restrictions ..........................................................................................................	509
Disposal of waste equipment by users in private households in the European
Union ...............................................................................................................................	509
Chemical substances .......................................................................................................	509
Material Safety Data Sheet (MSDS) ................................................................................	510
For more information .......................................................................................................	510
Declaration of Conformity .................................................................................................................	511
Safety statements .............................................................................................................................	512
Laser safety .....................................................................................................................	512
Canadian DOC regulations ..............................................................................................	512
VCCI statement (Japan) ..................................................................................................	512
Power cord instructions ...................................................................................................	512
Power cord statement (Japan) .........................................................................................	512
EMC statement (China) ...................................................................................................	513
EMC statement (Korea) ...................................................................................................	513
EMI statement (Taiwan) ...................................................................................................	513
Laser statement for Finland .............................................................................................	513
GS statement (Germany) .................................................................................................	514
Substances Table (China) ...............................................................................................	514
Restriction on Hazardous Substances statement (Turkey) .............................................	514
Index .................................................................................................................................................................	515

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List of tables

Table 1-1 Sequence of operation .......................................................................................................................		3
Table 1-2	Solenoids ...........................................................................................................................................	5
Table 1-3	Switches .............................................................................................................................................	6
Table 1-4	Sensors ..............................................................................................................................................	7
Table 1-5	Motors ................................................................................................................................................	8
Table 1-6	Fans ...................................................................................................................................................	9
Table 1-7 High-voltage power supply circuits ...................................................................................................		10
Table 1-8 Converted DC voltages ....................................................................................................................		12
Table 1-9	Fuser components ...........................................................................................................................	14
Table 1-10 Primary-transfer-roller engagement states .....................................................................................		32
Table 1-11	Image-stabilization controls ............................................................................................................	36
Table 1-12 Switches and sensors for the pickup, feed, and delivery system ...................................................		38
Table 1-13 Motors and solenoids for the pickup, feed, and delivery system ...................................................		39
Table 1-14 Print mode and feed speed ............................................................................................................		48
Table 1-15	Paper sizes ....................................................................................................................................	53
Table 1-16 Jams that the product detects ........................................................................................................		56
Table 1-17 Electrical components for the paper feeder ...................................................................................		59
Table 1-18 Pickup feed components (1 x 500-sheet paper feeder) .................................................................		60
Table 3-1	Pre-troubleshooting checklist .........................................................................................................	237
Table 3-2	Troubleshooting flowchart ..............................................................................................................	239
Table 3-3 Manual sensor diagnostic tests ......................................................................................................		246
Table 3-4 Default state of bits ........................................................................................................................		246
Table 3-5 Manual sensor test 2 diagnostic tests ............................................................................................		259
Table 3-6 Default state of bits ........................................................................................................................		260
Table 3-7 Paper-path sensors diagnostic tests ..............................................................................................		273
Table 3-8 Component test details ..................................................................................................................		274
Table 3-9	Formatter PCA ...............................................................................................................................	280
Table 3-10 DC controller connectors ..............................................................................................................		281
Table 3-11 Controller PCA connectors ...........................................................................................................		283
Table 3-12 Important information on the configuration pages ........................................................................		311
Table 3-13 Embedded Jetdirect menu ...........................................................................................................		334
Table 3-14	Control-panel messages ..............................................................................................................	345
Table 3-15 Common causes of jams (by area) ..............................................................................................		385
Table 3-16 Causes and solutions for delivery delay jam ................................................................................		394

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Table 3-17 Causes and solutions for fuser delivery delay jams .....................................................................		394
Table 3-18 Causes and solutions for wrapping jams .....................................................................................		394
Table 3-19 Causes and solutions for fuser delivery stationary jams ..............................................................		395
Table 3-20 Causes and solutions for residual media jams ............................................................................		396
Table 3-21 Causes and solutions for pickup delay jams 2 .............................................................................		396
Table 3-22 Causes and solutions for pickup stationary jams .........................................................................		397
Table 3-23 Causes and solutions for duplexing reverse jams ......................................................................		397
Table 3-24 Causes and solutions for duplex repick jams ..............................................................................		397
Table 3-25 Causes and solutions for residual media jams ............................................................................		398
Table 3-26 Causes and solutions for pickup delay jam 1: tray pickup ...........................................................		399
Table 3-27 Causes and solutions for pickup stationary jams .........................................................................		400
Table 3-28 Causes and solutions for pickup delay and pickup stationary jams .............................................		400
Table 3-29 Causes and solutions for residual media jams ............................................................................		401
Table 3-30 MP modes under the ADJUST PAPER TYPES sub menu .........................................................		408
Table 3-31 MP modes under the OPTIMIZE submenu ..................................................................................		409
Table 4-1	Maintenance kits ............................................................................................................................	428
Table 4-2 110V and 220V unique components ..............................................................................................		429
Table 4-3 Simplex and duplex unique components .......................................................................................		429
Table 4-4	Common fasteners ........................................................................................................................	430
Table 4-5 External covers, panels, and doors; ..............................................................................................		433
Table 4-6 Right door assembly ......................................................................................................................		435
Table 4-7 Front door assembly ......................................................................................................................		437
Table 4-8 Internal components (1 of 7) ..........................................................................................................		439
Table 4-9 Internal components (2 of 7) ..........................................................................................................		441
Table 4-10 Internal components (3 of 7) ........................................................................................................		443
Table 4-11 Internal components (4 of 7) ........................................................................................................		445
Table 4-12 Internal components (5 of 7) ........................................................................................................		447
Table 4-13 Internal components 6 of 7 ..........................................................................................................		449
Table 4-14 Internal components 7 of 7 ..........................................................................................................		451
Table 4-15	Cassette .......................................................................................................................................	453
Table 4-16	Paper pickup assembly ................................................................................................................	455
Table 4-17 Tray 1 paper pickup assembly .....................................................................................................		457
Table 4-18	Registration assembly ..................................................................................................................	459
Table 4-19 Secondary Transfer assembly .....................................................................................................		461
Table 4-20	Delivery assembly ........................................................................................................................	463
Table 4-21	Fuser assembly ............................................................................................................................	465
Table 4-22	PCAs ............................................................................................................................................	467
Table 4-23	Paper feeders ...............................................................................................................................	469
Table 4-24 Paper feeder external covers, panels, and doors ........................................................................		471
Table 4-25 1 X 500 paper feeder main body ..................................................................................................		473
Table 4-26 3 X 500 paper feeder main body ..................................................................................................		475
Table 4-27	Alphabetical parts list ...................................................................................................................	476
Table 4-28 Numerical parts list .......................................................................................................................		484
Table B-1	Product dimensions .......................................................................................................................	502

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Table B-2 Product dimensions, with all doors and trays fully opened ............................................................		502
Table B-3	Power requirements .......................................................................................................................	503
Table B-4	Power consumption (average, in watts)1246 ....................................................................................	503
Table B-5	HP Color LaserJet Enterprise CP4020-CP4520 Series13 ..............................................................	503
Table B-6	Media registration and image placement accuracy .......................................................................	504

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List of figures

Figure 1-1 Relationship between the main product systems .............................................................................		2
Figure 1-2	Engine-control system ......................................................................................................................	4
Figure 1-3 DC controller block diagram ..............................................................................................................		5
Figure 1-4 High-voltage power supply circuits .................................................................................................		10
Figure 1-5 Low-voltage power-supply circuit ....................................................................................................		12
Figure 1-6	Fuser components ..........................................................................................................................	14
Figure 1-7 Fuser temperature-control circuit ....................................................................................................		15
Figure 1-8	Laser/scanner system .....................................................................................................................	18
Figure 1-9 Protective-glass cleaners (PGCs) ...................................................................................................		20
Figure 1-10	Image-formation system ...............................................................................................................	21
Figure 1-11 Image-formation drive system .......................................................................................................		22
Figure 1-12	Image-formation process ..............................................................................................................	23
Figure 1-13	Pre-exposure ................................................................................................................................	24
Figure 1-14	Primary charging ...........................................................................................................................	24
Figure 1-15	Laser-beam exposure ...................................................................................................................	25
Figure 1-16	Development .................................................................................................................................	25
Figure 1-17	Primary transfer ............................................................................................................................	26
Figure 1-18	Secondary transfer ........................................................................................................................	26
Figure 1-19	Separation .....................................................................................................................................	27
Figure 1-20	Fusing ...........................................................................................................................................	27
Figure 1-21	ITB cleaning ..................................................................................................................................	28
Figure 1-22	Drum cleaning ...............................................................................................................................	28
Figure 1-23	Print-cartridge system ...................................................................................................................	29
Figure 1-24 Developing-roller engagement and disengagement control .........................................................		30
Figure 1-25	ITB unit ..........................................................................................................................................	31
Figure 1-26 Three states of primary-transfer-roller engagement and disengagement .....................................		33
Figure 1-27 ITB cleaning process ....................................................................................................................		34
Figure 1-28 Toner patterns for calibration ........................................................................................................		35
Figure 1-29	Paper path ....................................................................................................................................	37
Figure 1-30 Switches and sensors for the pickup, feed, and delivery system .................................................		38
Figure 1-31 Motors and solenoids for the pickup, feed, and delivery system ..................................................		39
Figure 1-32 Three main units of the pickup, feed, and delivery system ...........................................................		40
Figure 1-33	Pickup-and-feed unit .....................................................................................................................	41
Figure 1-34	Cassette-pickup mechanism .........................................................................................................	42

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Figure 1-35 Cassette lift mechanism ................................................................................................................		43
Figure 1-36	Multiple-feed prevention ................................................................................................................	44
Figure 1-37 Multipurpose tray pickup mechanism ............................................................................................		45
Figure 1-38	Paper-feed mechanism .................................................................................................................	46
Figure 1-39	Skew-feed prevention ...................................................................................................................	47
Figure 1-40 Fuser and delivery unit ..................................................................................................................		49
Figure 1-41	Loop-control mechanism ...............................................................................................................	50
Figure 1-42 Pressure-roller pressurization control ...........................................................................................		51
Figure 1-43	Duplexing unit ...............................................................................................................................	52
Figure 1-44 Duplex reverse and feed control ...................................................................................................		53
Figure 1-45 Jam detection sensors ..................................................................................................................		55
Figure 1-46 1 x 500 optional paper feeder .......................................................................................................		57
Figure 1-47 3 x 500-sheet optional paper feeder .............................................................................................		58
Figure 1-48 Signals for the paper feeder .........................................................................................................		58
Figure 1-49 Paper-feeder pickup and feed operation ......................................................................................		60
Figure 1-50 Paper-feeder cassette lift .............................................................................................................		63
Figure 1-51 Jam detection (1 x 500-sheet paper feeder) .................................................................................		64
Figure 1-52 Jam detection (3 x 500-sheet paper feeder) .................................................................................		65
Figure 2-1 Phillips and pozidrive screwdriver comparison ...............................................................................		69
Figure 2-2 Parts removal order (1 of 2) ............................................................................................................		72
Figure 2-3 Parts removal order (2 of 2) ............................................................................................................		73
Figure 2-4 Remove the print cartridge (1 of 2) .................................................................................................		74
Figure 2-5 Remove the print cartridge (2 of 2) .................................................................................................		75
Figure 2-6 Remove the toner-collection unit (1 of 4) ........................................................................................		76
Figure 2-7 Remove the toner-collection unit (2 of 4) ........................................................................................		76
Figure 2-8 Remove the toner-collection unit (3 of 4) ........................................................................................		77
Figure 2-9 Remove the toner-collection unit (4 of 4) ........................................................................................		77
Figure 2-10 Remove the formatter ...................................................................................................................		78
Figure 2-11 Remove the hard drive (1 of 3) .....................................................................................................		79
Figure 2-12 Remove the hard drive (2 of 3) .....................................................................................................		79
Figure 2-13 Remove the hard drive (3 of 3) .....................................................................................................		80
Figure 2-14 Remove the memory DIMM (1 of 2) ..............................................................................................		81
Figure 2-15 Remove the memory DIMM (2 of 2) ..............................................................................................		82
Figure 2-16 Remove the tray (1 of 2) ...............................................................................................................		84
Figure 2-17 Remove the tray (2 of 2) ...............................................................................................................		84
Figure 2-18 Remove the fuser (1 of 2) .............................................................................................................		85
Figure 2-19 Remove the fuser (2 of 2) .............................................................................................................		85
Figure 2-20 Remove the Pickup and feed rollers (Trays 2-5) ..........................................................................		86
Figure 2-21 Remove the pickup roller (Tray 1) (1 of 5) ....................................................................................		87
Figure 2-22 Remove the pickup roller (Tray 1) (2 of 5) ....................................................................................		87
Figure 2-23 Remove the pickup roller (Tray 1) (3 of 5) ....................................................................................		88
Figure 2-24 Remove the pickup roller (Tray 1) (4 of 5) ....................................................................................		88
Figure 2-25 Remove the pickup roller (Tray 1) (5 of 5) ....................................................................................		89
Figure 2-26 Remove the transfer roller (1 of 3) ................................................................................................		90

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Figure 2-27 Remove the transfer roller (2 of 3) ................................................................................................	90
Figure 2-28 Remove the transfer roller (3 of 3) ................................................................................................	91
Figure 2-29 Reinstall the transfer roller ............................................................................................................	91
Figure 2-30 Remove the intermediate transfer belt (1 of 4) .............................................................................	92
Figure 2-31 Remove the intermediate transfer belt (2 of 4) .............................................................................	92
Figure 2-32 Remove the intermediate transfer belt (3 of 4) .............................................................................	93
Figure 2-33 Remove the intermediate transfer belt (4 of 4) .............................................................................	94
Figure 2-34 External panels, covers, and doors; identification and location ....................................................	95
Figure 2-35 Remove the upper-left cover (1 of 3) ............................................................................................	96
Figure 2-36 Remove the upper-left cover (2 of 3) ............................................................................................	96
Figure 2-37 Remove the upper-left cover (3 of 3) ............................................................................................	97
Figure 2-38 Remove the power-supply cover ..................................................................................................	98
Figure 2-39 Remove the left cover (1 of 2) .......................................................................................................	99
Figure 2-40 Remove the left cover (2 of 2) .......................................................................................................	99
Figure 2-41 Remove the front-top cover (1 of 3) ............................................................................................	100
Figure 2-42 Remove the front-top cover (2 of 3) ............................................................................................	100
Figure 2-43 Remove the front-top cover (3 of 3) ............................................................................................	101
Figure 2-44 Remove the rear-top cover (1 of 2) .............................................................................................	102
Figure 2-45 Remove the rear-top cover (2 of 2) .............................................................................................	102
Figure 2-46 Remove the right-front cover (1 of 3) ..........................................................................................	103
Figure 2-47 Remove the right-front cover (2 of 3) ..........................................................................................	103
Figure 2-48 Remove the right-front cover (3 of 3) ..........................................................................................	104
Figure 2-49 Reinstall the power button ..........................................................................................................	104
Figure 2-50 Remove the control-panel assembly (1 of 2) ..............................................................................	105
Figure 2-51 Remove the control-panel assembly (2 of 2) ..............................................................................	106
Figure 2-52 Remove the front-door assembly (1 of 5) ...................................................................................	107
Figure 2-53 Remove the front-door assembly (2 of 5) ...................................................................................	108
Figure 2-54 Remove the front-door assembly (3 of 5) ...................................................................................	108
Figure 2-55 Remove the front-door assembly (4 of 5) ...................................................................................	109
Figure 2-56 Remove the front-door assembly (5 of 5) ...................................................................................	109
Figure 2-57 Remove the right-rear cover (1 of 2) ...........................................................................................	110
Figure 2-58 Remove the right-rear cover (2 of 2) ...........................................................................................	111
Figure 2-59 Remove the rear cover ...............................................................................................................	112
Figure 2-60 Remove the right-door assembly (1 of 9) ...................................................................................	113
Figure 2-61 Remove the right-door assembly (2 of 9) ...................................................................................	113
Figure 2-62 Remove the right-door assembly (3 of 9) ...................................................................................	114
Figure 2-63 Remove the right-door assembly (4 of 9) ...................................................................................	114
Figure 2-64 Remove the right-door assembly (5 of 9) ...................................................................................	115
Figure 2-65 Remove the right-door assembly (6 of 9) ...................................................................................	115
Figure 2-66 Remove the right-door assembly (7 of 9) ...................................................................................	116
Figure 2-67 Remove the right-door assembly (8 of 9) ...................................................................................	116
Figure 2-68 Remove the right-door assembly (9 of 9) ...................................................................................	117
Figure 2-69 Remove the cassette feed guide (1 of 2) ....................................................................................	118
Figure 2-70 Remove the cassette feed (2 of 2) ..............................................................................................	118

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Figure 2-71 Remove the secondary transfer assembly (1 of 3) .....................................................................	119
Figure 2-72 Remove the secondary transfer assembly (2 of 3) .....................................................................	119
Figure 2-73 Remove the secondary transfer assembly (3 of 3) .....................................................................	120
Figure 2-74 Reinstall the secondary transfer assembly .................................................................................	120
Figure 2-75 Remove the separation pad (1 of 6) ...........................................................................................	121
Figure 2-76 Remove the separation pad (2 of 6) ...........................................................................................	121
Figure 2-77 Remove the separation pad (3 of 6) ...........................................................................................	122
Figure 2-78 Remove the separation pad (4 of 6) ...........................................................................................	122
Figure 2-79 Remove the separation pad (5 of 6) ...........................................................................................	123
Figure 2-80 Remove the separation pad (6 of 6) ...........................................................................................	123
Figure 2-81 Remove the RD sensor assembly (1 of 7) ..................................................................................	124
Figure 2-82 Remove the RD sensor assembly (2 of 7) ..................................................................................	124
Figure 2-83 Remove the RD sensor assembly (3 of 7) ..................................................................................	125
Figure 2-84 Remove the RD sensor assembly (4 of 7) ..................................................................................	125
Figure 2-85 Remove the RD sensor assembly (5 of 7) ..................................................................................	126
Figure 2-86 Remove the RD sensor assembly (6 of 7) ..................................................................................	126
Figure 2-87 Remove the RD sensor assembly (7 of 7) ..................................................................................	127
Figure 2-88 Remove the registration assembly (1 of 8) .................................................................................	129
Figure 2-89 Remove the registration assembly (2 of 8) .................................................................................	129
Figure 2-90 Remove the registration assembly (3 of 8) .................................................................................	130
Figure 2-91 Remove the registration assembly (4 of 8) .................................................................................	130
Figure 2-92 Remove the registration assembly (5 of 8) .................................................................................	131
Figure 2-93 Remove the registration assembly (6 of 8) .................................................................................	131
Figure 2-94 Remove the registration assembly (7 of 8) .................................................................................	132
Figure 2-95 Remove the registration assembly (8 of 8) .................................................................................	132
Figure 2-96 Remove the residual-toner-feed motor .......................................................................................	133
Figure 2-97 Remove the residual-toner duct and feed assembly (1 of 4) ......................................................	134
Figure 2-98 Remove the residual-toner duct and feed assembly (2 of 4) ......................................................	135
Figure 2-99 Remove the residual-toner duct and feed assembly (3 of 4) ......................................................	135
Figure 2-100 Remove residual-toner duct and feed assembly (4 of 4) ..........................................................	136
Figure 2-101 Remove the cartridge fan and environmental sensor (1 of 7) ...................................................	137
Figure 2-102 Remove the cartridge fan and environmental sensor (2 of 7) ...................................................	138
Figure 2-103 Remove the cartridge fan and environmental sensor (3 of 7) ...................................................	138
Figure 2-104 Remove the cartridge fan and environmental sensor (4 of 7) ...................................................	139
Figure 2-105 Remove the cartridge fan and environmental sensor (5 of 7) ...................................................	139
Figure 2-106 Remove the cartridge fan and environmental sensor (6 of 7) ...................................................	140
Figure 2-107 Remove the cartridge fan and environmental sensor (7 of 7) ...................................................	140
Figure 2-108 Remove the toner-collection sensor and scanner-thermistor assembly (1 of 3) .......................	141
Figure 2-109 Remove the toner-collection sensor and scanner-thermistor assembly (2 of 3) .......................	142
Figure 2-110 Remove the toner-collection sensor and scanner-thermistor assembly (3 of 3) .......................	142
Figure 2-111 Remove the delivery fan (1 of 2) ...............................................................................................	143
Figure 2-112 Remove the delivery fan (2 of 2) ...............................................................................................	144
Figure 2-113 Remove the delivery assembly (1 of 7) ....................................................................................	145
Figure 2-114 Remove the delivery assembly (2 of 7) ....................................................................................	146

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Figure 2-115 Remove the delivery assembly (3 of 7) ....................................................................................	146
Figure 2-116 Remove the delivery assembly (4 of 7) ....................................................................................	147
Figure 2-117 Remove the delivery assembly (5 of 7) ....................................................................................	147
Figure 2-118 Remove the delivery assembly (6 of 7) ....................................................................................	148
Figure 2-119 Remove the delivery assembly (7 of 7) ....................................................................................	148
Figure 2-120 Reinstall the delivery assembly (1 of 4) ....................................................................................	149
Figure 2-121 Reinstall the delivery assembly (2 of 4) ....................................................................................	149
Figure 2-122 Reinstall the delivery assembly (3 of 4) ....................................................................................	150
Figure 2-123 Reinstall the delivery assembly (4 of 4) ....................................................................................	150
Figure 2-124 Remove the duplex-drive assembly .........................................................................................	151
Figure 2-125 Remove the power-supply fan ..................................................................................................	152
Figure 2-126 Remove the ICB (1 of 2) ...........................................................................................................	153
Figure 2-127 Remove the ICB (2 of 2) ...........................................................................................................	154
Figure 2-128 Remove the DC controller PCA only (1 of 2) ............................................................................	155
Figure 2-129 Remove the DC controller PCA only (2 of 2) ............................................................................	156
Figure 2-130 Remove the low-voltage power supply (1 of 6) .........................................................................	157
Figure 2-131 Remove the low-voltage power supply (1 of 6) .........................................................................	158
Figure 2-132 Remove the low-voltage power supply (2 of 6) .........................................................................	158
Figure 2-133 Remove the low-voltage power supply (3 of 6) .........................................................................	159
Figure 2-134 Remove the low-voltage power supply (4 of 6) .........................................................................	159
Figure 2-135 Remove the low-voltage power supply (5 of 6) .........................................................................	160
Figure 2-136 Remove the low-voltage power supply (6 of 6) .........................................................................	160
Figure 2-137 Remove the DC controller PCA and tray (1 of 3) ......................................................................	161
Figure 2-138 Remove the DC controller PCA and tray (2 of 3) ......................................................................	162
Figure 2-139 Remove the DC controller PCA and tray (3 of 3) ......................................................................	162
Figure 2-140 Remove the high-voltage power supply lower (1 of 7) ..............................................................	163
Figure 2-141 Remove the high-voltage power supply lower (2 of 7) ..............................................................	164
Figure 2-142 Remove the high-voltage power supply lower (3 of 7) ..............................................................	165
Figure 2-143 Remove the high-voltage power supply lower (4 of 7) ..............................................................	165
Figure 2-144 Remove the high-voltage power supply lower (5 of 7) ..............................................................	166
Figure 2-145 Remove the high-voltage power supply lower (6 of 7) ..............................................................	166
Figure 2-146 Remove the high-voltage power supply lower (7 of 7) ..............................................................	167
Figure 2-147 Reinstall the high-voltage power supply lower ..........................................................................	167
Figure 2-148 Remove the developing-disengagement motor ........................................................................	168
Figure 2-149 Remove the exhaust fan and fan duct (1 of 3) ..........................................................................	169
Figure 2-150 Remove the exhaust fan and fan duct (2 of 3) ..........................................................................	170
Figure 2-151 Remove the exhaust fan and fan duct (3 of 3) ..........................................................................	170
Figure 2-152 Reinstall the exhaust fan and fan duct .....................................................................................	171
Figure 2-153 Remove the pickup motor .........................................................................................................	172
Figure 2-154 Remove the lifter-drive assembly (1 of 2) .................................................................................	173
Figure 2-155 Remove the lifter-drive assembly (2 of 3) .................................................................................	174
Figure 2-156 Remove the lifter-drive assembly (3 of 3) .................................................................................	174
Figure 2-157 Remove the lifter base assembly (1 of 2) .................................................................................	175
Figure 2-158 Remove the lifter base assembly (2 of 2) .................................................................................	176

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Figure 2-159 Reinstall the lifter base assembly (1 of 2) .................................................................................	176
Figure 2-160 Reinstall the lifter base assembly (2 of 2) .................................................................................	177
Figure 2-161 Remove the tray-pickup drive assembly (1 of 3) ......................................................................	178
Figure 2-162 Remove the tray-pickup drive assembly (2 of 3) ......................................................................	179
Figure 2-163 Remove the tray-pickup drive assembly (3 of 3) ......................................................................	179
Figure 2-164 Remove the tray-pickup assembly (1 of 11) .............................................................................	180
Figure 2-165 Remove the tray-pickup assembly (2 of 11) .............................................................................	181
Figure 2-166 Remove the tray-pickup assembly (3 of 11) .............................................................................	181
Figure 2-167 Remove the tray-pickup assembly (4 of 11) .............................................................................	182
Figure 2-168 Remove the tray-pickup assembly (5 of 11) .............................................................................	182
Figure 2-169 Remove the tray-pickup assembly (6 of 11) .............................................................................	183
Figure 2-170 Remove the tray-pickup assembly (7 of 11) .............................................................................	183
Figure 2-171 Remove the tray-pickup assembly (8 of 11) .............................................................................	184
Figure 2-172 Remove the tray-pickup assembly (9 of 11) .............................................................................	184
Figure 2-173 Remove the tray-pickup assembly (10 of 11) ...........................................................................	185
Figure 2-174 Remove the tray-pickup assembly (11 of 11) ...........................................................................	185
Figure 2-175 Remove the laser/scanner assembly (Y/M) (1 of 5) .................................................................	187
Figure 2-176 Remove the laser/scanner assembly (Y/M) (2 of 5) .................................................................	187
Figure 2-177 Remove the laser/scanner assembly (Y/M) (3 of 5) .................................................................	188
Figure 2-178 Remove the laser/scanner assembly (Y/M) (4 of 5). ................................................................	189
Figure 2-179 Remove the laser/scanner assembly (Y/M) (5 of 5) .................................................................	189
Figure 2-180 Remove the laser/scanner assembly (C/Bk) (1 of 5) ................................................................	191
Figure 2-181 Remove the laser/scanner assembly (C/Bk) (2 of 5) ................................................................	191
Figure 2-182 Remove the laser/scanner assembly (C/Bk) (3 of 5) ................................................................	192
Figure 2-183 Remove the laser/scanner assembly (C/Bk) (4 of 5) ................................................................	192
Figure 2-184 Remove the laser/scanner assembly (C/Bk) (5 of 5) ................................................................	193
Figure 2-185 Reinstall the PGC actuators (1 of 5) .........................................................................................	193
Figure 2-186 Reinstall the PGC actuators (2 of 5) .........................................................................................	194
Figure 2-187 Reinstall the PGC actuators (3 of 5) .........................................................................................	194
Figure 2-188 Reinstall the PGC actuators (4 of 5) .........................................................................................	195
Figure 2-189 Reinstall the PGC actuators (5 of 5) .........................................................................................	195
Figure 2-190 Remove the high-voltage power supply upper (1 of 2) .............................................................	196
Figure 2-191 Remove the high-voltage power supply upper (2 of 2) .............................................................	197
Figure 2-192 Reinstall the high-voltage power supply upper .........................................................................	198
Figure 2-193 Remove the yellow, magenta, cyan, and black drum motors ...................................................	199
Figure 2-194 Remove the fuser motor ...........................................................................................................	201
Figure 2-195 Remove the ITB motor (1 of 2) .................................................................................................	202
Figure 2-196 Remove the main-drive assembly (1 of 6) ................................................................................	204
Figure 2-197 Remove the main-drive assembly (2 of 6) ................................................................................	204
Figure 2-198 Remove the main-drive assembly (3 of 6) ................................................................................	205
Figure 2-199 Remove the main-drive assembly (4 of 6) ................................................................................	205
Figure 2-200 Remove the main-drive assembly (5 of 6) ................................................................................	206
Figure 2-201 Remove the main-drive assembly (6 of 6) ................................................................................	206
Figure 2-202 Reinstall the main-drive assembly (1 of 7) ................................................................................	207

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Figure 2-203 Reinstall the main-drive assembly (2 of 7) ................................................................................	207
Figure 2-204 Reinstall the main-drive assembly (3 of 7) ................................................................................	208
Figure 2-205 Reinstall the main-drive assembly (4 of 7) ................................................................................	209
Figure 2-206 Reinstall the main-drive assembly (5 of 7) ................................................................................	209
Figure 2-207 Reinstall the main-drive assembly (6 of 7) ................................................................................	210
Figure 2-208 Reinstall the main-drive assembly (7 of 7) ................................................................................	210
Figure 2-209 Remove the fuser-drive assembly (1 of 7) ................................................................................	212
Figure 2-210 Remove the fuser-drive assembly (2 of 7) ................................................................................	212
Figure 2-211 Remove the fuser-drive assembly (3 of 7) ................................................................................	213
Figure 2-212 Remove the fuser-drive assembly (4 of 7) ................................................................................	213
Figure 2-213 Remove the fuser-drive assembly (5 of 7) ................................................................................	214
Figure 2-214 Remove the fuser-drive assembly (6 of 7) ................................................................................	214
Figure 2-215 Remove the fuser-drive assembly (7 of 7) ................................................................................	215
Figure 2-216 Reinstall the fuser-drive assembly ............................................................................................	215
Figure 2-217 Remove the front door (optional paper feeder) (1 of 2) ............................................................	216
Figure 2-218 Remove the front door (optional paper feeder) (2 of 2) ............................................................	217
Figure 2-219 Remove the rear cover (optional paper feeder) ........................................................................	218
Figure 2-220 Remove the right-front cover (optional paper feeder) ..............................................................	219
Figure 2-221 Remove the right door (optional paper feeder) (1 of 3) ............................................................	220
Figure 2-222 Remove the right door (optional paper feeder) (2 of 3) ............................................................	220
Figure 2-223 Remove the right door (optional paper feeder) (3 of 3) ............................................................	221
Figure 2-224 Remove the left cover (optional paper feeder) (1 of 3) .............................................................	222
Figure 2-225 Remove the left cover (optional paper feeder) (2 of 3) .............................................................	223
Figure 2-226 Remove the left cover (optional paper feeder) (3 of 3) .............................................................	223
Figure 2-227 Remove the right cover (optional paper feeder) ......................................................................	224
Figure 2-228 Remove the rear-right cover (optional paper feeder) ...............................................................	225
Figure 2-229 Remove the pickup assembly (optional paper feeder) (1 of 5) .................................................	226
Figure 2-230 Remove the pickup assembly (optional paper feeder) (2 of 5) .................................................	227
Figure 2-231 Remove the pickup assembly (optional paper feeder) (3 of 5) .................................................	227
Figure 2-232 Remove the pickup assembly (optional paper feeder) (4 of 5) .................................................	228
Figure 2-233 Remove the pickup assembly (optional paper feeder) (5 of 5) .................................................	228
Figure 2-234 Remove the lifter assembly (optional paper feeder) (1 of 2) .....................................................	229
Figure 2-235 Remove the lifter assembly (optional paper feeder) (2 of 2) .....................................................	229
Figure 2-236 Remove the lifter-drive assembly (optional paper feeder) (1 of 2) ............................................	230
Figure 2-237 Remove the lifter-drive assembly (optional paper feeder) (2 of 2) ............................................	230
Figure 2-238 Remove the pickup motor assembly (optional paper feeder) (1 of 2) .......................................	231
Figure 2-239 Remove the pickup motor assembly (optional paper feeder) (2 of 2) .......................................	231
Figure 2-240 Remove the controller PCA (optional paper feeder) (1 of 2) ....................................................	232
Figure 2-241 Remove the controller PCA (optional paper feeder) (2 of 2) ....................................................	232
Figure 3-1 Diagnostic test (1 of 2) ..................................................................................................................	243
Figure 3-2 Diagnostic test (2 of 2) ..................................................................................................................	244
Figure 3-3 Engine-test button .........................................................................................................................	245
Figure 3-4 Test the TOP sensor (1 of 2) ........................................................................................................	247
Figure 3-5 Test the TOP sensor (2 of 2) ........................................................................................................	247

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Figure 3-6 Test the loop sensors ....................................................................................................................		248
Figure 3-7 Test the fuser delivery sensor (1 of 2) ..........................................................................................		249
Figure 3-8 Test the fuser delivery sensor (2 of 2) ..........................................................................................		249
Figure 3-9 Test the duplex re-pickup sensor ..................................................................................................		250
Figure 3-10 Test the output-bin-full sensor ....................................................................................................		251
Figure 3-11 Test the fuser pressure-release sensor ......................................................................................		253
Figure 3-12 Test the primary transfer-roller-disengagement sensor (1 of 4) .................................................		254
Figure 3-13 Test the primary transfer-roller-disengagement sensor (2 of 4) .................................................		254
Figure 3-14 Test the primary transfer-roller-disengagement sensor (3 of 4) .................................................		255
Figure 3-15 Test the primary transfer-roller-disengagement sensor (4 of 4) .................................................		255
Figure 3-16	Media sensor ..............................................................................................................................	256
Figure 3-17 Test the front-door switch ...........................................................................................................		257
Figure 3-18 Test the right door switch ............................................................................................................		258
Figure 3-19 Test the Tray 1 media-present sensor .......................................................................................		261
Figure 3-20 Test the tray 2 paper-present sensor .........................................................................................		262
Figure 3-21 Tray 2 paper surface 1 and 2 ......................................................................................................		263
Figure 3-22 Test the Tray 2 paper size switches ...........................................................................................		264
Figure 3-23 Test the Tray 3 feed sensor ........................................................................................................		265
Figure 3-24 Test the new ITB sensor .............................................................................................................		271
Figure 3-25 Test the new ITB sensor .............................................................................................................		271
Figure 3-26 Test the right door switch ............................................................................................................		272
Figure 3-27 Product cross section ..................................................................................................................		277
Figure 3-28 Optional paper feeder (1 x 500-sheet) ........................................................................................		278
Figure 3-29 Optional paper feeder (3 x 500-sheet) ........................................................................................		279
Figure 3-30	Formatter PCA ............................................................................................................................	280
Figure 3-31 DC controller connector locations ...............................................................................................		281
Figure 3-32 Controller PCA connectors .........................................................................................................		283
Figure 3-33 External component locations .....................................................................................................		284
Figure 3-34 Major component locations (1 of 3) ............................................................................................		285
Figure 3-35 Major component locations (2 of 3) ............................................................................................		286
Figure 3-36 Major component locations (3 of 3) ............................................................................................		287
Figure 3-37 Motors, fans, and rollers component locations ...........................................................................		288
Figure 3-38 PCA component locations ..........................................................................................................		289
Figure 3-39 Optional paper feeder (1 x 500-sheet) component locations (1 of 2) .........................................		290
Figure 3-40 Optional paper feeder (1 x 500-sheet) component locations (2 of 2) .........................................		291
Figure 3-41 Optional paper feeder (3 x 500-sheet) component locations (1 of 2) .........................................		292
Figure 3-42 Optional paper feeder (3 x 500-sheet) component locations (2 of 2) .........................................		293
Figure 3-43 General timing chart ....................................................................................................................		294
Figure 3-44 General circuit diagram (1 of 2) ..................................................................................................		295
Figure 3-45 General circuit diagram (1 of 2) ..................................................................................................		295
Figure 3-46 Paper feeder circuit diagram (1 X 500-sheet) .............................................................................		296
Figure 3-47 Paper feeder circuit diagram (3 X 500-sheet) .............................................................................		297
Figure 3-48 Print-quality troubleshooting procedure ......................................................................................		302
Figure 3-49 Yellow print-quality troubleshooting page ...................................................................................		303

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Figure 3-50 Yellow comparison page .............................................................................................................		303
Figure 3-51 Black print-quality troubleshooting page .....................................................................................		304
Figure 3-52	Configuration page .....................................................................................................................	307
Figure 3-53 HP embedded Jetdirect page .....................................................................................................		309
Figure 3-54 Embedded protocol page ...........................................................................................................		310
Figure 3-55 Repetitive defects ruler ...............................................................................................................		312
Figure 3-56 Sample event log ........................................................................................................................		377
Figure 3-57 Common causes of jams (by area) .............................................................................................		384
Figure 3-58	Jam locations ..............................................................................................................................	386
Figure 4-1 External covers, panels, and doors ..............................................................................................		432
Figure 4-2 Right door assembly .....................................................................................................................		434
Figure 4-3 Front door assembly .....................................................................................................................		436
Figure 4-4 Internal components 1 of 7 ...........................................................................................................		438
Figure 4-5 Internal components 2 of 7 ...........................................................................................................		440
Figure 4-6 Internal components 3 of 7 ...........................................................................................................		442
Figure 4-7 Internal components 4 of 7 ...........................................................................................................		444
Figure 4-8 Internal components 5 of 7 ...........................................................................................................		446
Figure 4-9 Internal components 6 of 7 ...........................................................................................................		448
Figure 4-10 Internal components 7 of 7 .........................................................................................................		450
Figure 4-11	Cassettes 2-5 ..............................................................................................................................	452
Figure 4-12 Paper pickup assembly ...............................................................................................................		454
Figure 4-13 Tray 1 paper pickup assembly ....................................................................................................		456
Figure 4-14	Registration assembly ................................................................................................................	458
Figure 4-15 Secondary transfer assembly ....................................................................................................		460
Figure 4-16	Delivery assembly ......................................................................................................................	462
Figure 4-17	Fuser assembly ...........................................................................................................................	464
Figure 4-18	PCAs ...........................................................................................................................................	466
Figure 4-19	Paper feeders .............................................................................................................................	468
Figure 4-20 Paper feeder external covers, panels, and doors .......................................................................		470
Figure 4-21 1 X 500 paper feeder main body ................................................................................................		472
Figure 4-22 3 X 500 paper feeder main body ................................................................................................		474

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xxix

1 Theory of operation

●Basic operation

●Engine-control system

●Laser/scanner system

●Image-formation system

●Pickup, feed, and delivery system

●Jam detection

●Optional paper feeder

ENWW

1

Basic operation

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

The basic product 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 media feed system, which uses a system of rollers and belts to transport the paper through the product

●Option (optional paper feeder)

Figure 1-1 Relationship between the main product systems

Laser/scanner system

Image-formation system

Engine control system

Media-feed system

Option

2 Chapter 1 Theory of operation

ENWW

● Stops the high-voltage power supply

● Stops each laser/scanner unit

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

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	● Heats the fuser sleeve in the fuser
	door is closed, or when the product exits	● Pressurizes the pressure roller in
	Sleep mode until the product is ready for
	printing	the fuser
		● Detects the print cartridges
		● Moves the ITB and developing unit
		to the home position
		● Cleans the ITB and secondary
		transfer roller
Standby	From the end of the waiting sequence or	● The product is in the READY state.
	the last rotation until the formatter	● The product enters Sleep mode if
	receives a print command or until the
	product is turned off	the sleep command is received
		from the formatter.
		● The product calibrates if it is time for
		an automatic calibration.
Initial rotation	From the time the formatter receives a	● Activates the high-voltage power
	print command until the paper enters the	supply
	paper path	● Prepares each laser/scanner unit
		● Warms the fuser to the correct
		temperature
Printing	From the time the first sheet of paper	● Forms the image on the
	enters the paper path until the last sheet	photosensitive drums
	has passed through the fuser	● Transfers the toner to the paper
		● Fuses the toner image onto the
		paper
Last rotation	From the time the last sheet of paper	● Moves the last printed sheet into the
	exits the fuser until the motors stop	output bin
	rotating

ENWW	Basic operation 3

Engine-control system

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

●DC controller

●Low-voltage power supply

●High-voltage power supply

●Fuser control

Figure 1-2 Engine-control system

ENGINE CONTROL SYSTEM

LASER SCANNER SYSTEM

DC controller

IMAGE-FORMATION SYSTEM

Low-voltage power supply

Formatter

High-voltage power supply	MEDIA FEED SYSTEM

Fuser control

OPTION

4 Chapter 1 Theory of operation

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