LASERJET ENTERPRISE 500 COLOR
Service Manual
M551n M551dn M551xh
HP LaserJet Enterprise 500 color M551
Printers
Service Manual
Copyright and License
© 2011 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: CF079-90942
Edition 1, 10/2011
Trademark Credits
®
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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iv Conventions used in this guide ENWW
Table of contents
1 Theory of operation .......................................................................................................... 1
Basic operation ........................................................................................................................ 2
Sequence of operation ............................................................................................... 3
Engine control system ............................................................................................................... 4
DC controller ............................................................................................................ 5
Solenoids .................................................................................................. 6
Clutches .................................................................................................... 6
Switches ................................................................................................... 6
Sensors ..................................................................................................... 7
Motors and fans ......................................................................................... 7
High voltage power supply ...................................................................................... 10
Low voltage power supply ........................................................................................ 12
Overcurrent/overvoltage protection ............................................................ 14
Safety ..................................................................................................... 14
Sleep (powersave) mode ........................................................................... 14
Power supply voltage detection .................................................................. 14
Low voltage power supply failure ............................................................... 14
Power off condition .................................................................................. 15
Fuser control ........................................................................................................... 15
Fuser temperature control circuit ................................................................. 16
Fuser over temperature protection ............................................................... 17
Fuser failure detection ............................................................................... 18
Laser/scanner system ............................................................................................................. 19
Image formation system .......................................................................................................... 21
Image formation process .......................................................................................... 22
Step 1: Pre-exposure ................................................................................. 23
Step 2: Primary charging .......................................................................... 23
Step 3: Laser-beam exposure ..................................................................... 24
Step 4: Development ................................................................................ 24
Step 5: Primary transfer ............................................................................ 25
Step 6: Secondary transfer ........................................................................ 25
Step 7: Separation ................................................................................... 26
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Step 8: Fusing ......................................................................................... 26
Step 9: ITB cleaning ................................................................................. 27
Step 10: Drum cleaning ............................................................................ 27
Print cartridge ......................................................................................................... 27
Developing roller engagement and disengagement ..................................................... 29
Intermediate transfer belt (ITB) unit ............................................................................. 31
Primary-transfer-roller engagement and disengagement ................................. 32
ITB cleaning ............................................................................................ 35
Calibration ............................................................................................................. 36
Color misregistration control ...................................................................... 36
Image stabilization control ........................................................................ 37
Pickup, feed, and delivery system ............................................................................................. 38
Pickup-and-feed unit ................................................................................................ 42
Cassette pickup ........................................................................................ 43
Cassette presence detection ........................................................ 44
Cassette lift operation ................................................................ 45
Cassette paper presence detection .............................................. 46
Cassette media width detection ................................................... 47
Multifeed prevention .................................................................. 48
Multipurpose tray pickup ........................................................................... 49
Paper feed .............................................................................................. 50
Skew-feed prevention ................................................................. 51
OHT detection .......................................................................... 52
Fusing and delivery unit ........................................................................................... 52
Loop control ............................................................................................ 53
Pressure-roller pressurization control ........................................................... 54
Duplexing unit (duplex models) ................................................................................. 55
Duplexing reverse and feed control ............................................................ 56
Duplex pickup operation ........................................................................... 56
Jam detection ........................................................................................................................ 57
Optional paper feeder ............................................................................................................ 59
Paper-feeder pickup and feed operation .................................................................... 61
Paper size detection and cassette presence detection .................................................. 62
Paper feeder cassette lift operation ............................................................................ 64
Paper feeder presence detection ............................................................................... 66
Paper-feeder multiple feed prevention ........................................................................ 67
Paper feeder jam detection ....................................................................................... 68
2 Removal and replacement .........................................
Introduction ........................................................................................................................... 70
Removal and replacement strategy ........................................................................................... 70
vi ENWW
..................................................... 69
Cautions during removal and replacement ................................................................. 70
Electrostatic discharge ............................................................................................. 71
Required tools ......................................................................................................... 72
Service approach ................................................................................................................... 73
Before performing service ........................................................................................ 73
After performing service ........................................................................................... 73
Post service test ....................................................................................................... 73
Print-quality test ........................................................................................ 73
Parts removal order ................................................................................................. 74
Customer self repair (CSR) components ..................................................................................... 76
Print cartridges ........................................................................................................ 76
Duplex reverse guide ............................................................................................... 78
Toner collection unit ................................................................................................ 79
Formatter PCA ........................................................................................................ 81
Disk drives ............................................................................................................. 82
Remove the HDD ...................................................................................... 82
Remove the SSM ...................................................................................... 84
Install a replacement hard drive ................................................................. 85
Reload the firmware .................................................................. 85
Tray cassette .......................................................................................................... 86
Fuser ..................................................................................................................... 87
Pickup roller (Tray 1) ............................................................................................... 88
Pickup roller (Tray 2) ............................................................................................... 89
Pickup and feed rollers (Tray 3) ................................................................................ 91
Separation roller (Tray 2) ......................................................................................... 93
Secondary transfer roller .......................................................................................... 94
Reinstall the transfer roller ......................................................................... 95
Secondary transfer assembly .................................................................................... 96
Reinstall the secondary transfer assembly .................................................... 97
Intermediate transfer belt (ITB) ................................................................................... 98
Right door (optional paper feeder) .......................................................................... 100
Covers ................................................................................................................................ 102
Identification and location ...................................................................................... 102
Front door assembly .............................................................................................. 103
Right door assembly .........................................
Right rear cover .................................................................................................... 109
Left cover ............................................................................................................. 111
Remove the left cover .............................................................................. 111
Left bottom cover ................................................................................................... 113
Remove the left bottom cover ................................................................... 113
Left bottom handle ................................................................................................. 114
..................................................... 105
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Remove the left bottom handle ................................................................. 114
Hardware integration pocket (HIP) (dn and xh models only) ....................................... 115
Control panel assembly ......................................................................................... 116
Right front cover .................................................................................................... 118
Remove the right front cover .................................................................... 118
Reinstall the power button ........................................................ 121
Front top cover ..................................................................................................... 122
Remove the front top cover ...................................................................... 122
Rear cover and upper rear cover ............................................................................ 124
Remove the rear cover and upper rear cover ............................................. 124
Rear top cover ...................................................................................................... 127
Remove the rear top cover ....................................................................... 127
Right bottom handle .............................................................................................. 129
Remove the right bottom handle ............................................................... 129
Rear bottom handle ............................................................................................... 130
Remove the rear bottom handle ................................................................ 130
Internal assemblies ............................................................................................................... 131
Delivery fan, cartridge fan, and environmental sensor ................................................ 131
Remove the delivery fan, cartridge fan, and environmental sensor ................ 131
Toner collection sensor ........................................................................................... 136
Remove the toner collection sensor ........................................................... 136
Residual toner feed motor ....................................................................................... 138
Remove the residual toner feed motor ....................................................... 138
Reinstall the residual toner collection door .................................. 142
Registration density (RD) sensor assembly ................................................................. 143
Remove the RD sensor assembly ............................................................... 143
Power supply fan and fan duct ................................................................................ 147
Remove the power supply fan and fan duct ............................................... 147
Registration assembly ............................................................................................ 150
Remove the registration assembly ............................................................. 150
Lower pickup guide ............................................................................................... 155
Remove the lower pickup guide ............................................................... 155
Reinstall the lower pickup guide ............................................................... 157
Interconnect board (ICB) ........................................................................................ 158
Remove the ICB ...................................................................................... 158
DC controller PCA and tray .................................................................................... 160
Remove the DC controller PCA ................................................................. 160
Low voltage power supply ...................................................................................... 163
ve the low voltage power supply ...................................................... 163
Remo
High voltage power supply lower (HVPS-D) .............................................................. 167
Remove the high voltage power supply lower ............................................ 167
viii ENWW
Reinstall the high voltage power supply lower ............................. 169
Developing disengagement motor ........................................................................... 170
Remove the developing disengagement motor ........................................... 170
Pickup motor ........................................................................................................ 172
Remove the pickup motor ........................................................................ 172
Lifter drive assembly .............................................................................................. 173
Remove the lifter drive assembly ............................................................... 173
Automatic close assembly ....................................................................................... 175
Remove the automatic close assembly ....................................................... 175
Cassette pickup drive assembly ............................................................................... 176
Remove the cassette pickup drive assembly ............................................... 176
Reinstall the cassette pickup drive assembly ................................ 181
Cassette pickup assembly ....................................................................................... 183
Remove the cassette pickup assembly ....................................................... 184
Laser/scanner assembly (Y/M) ............................................................................... 186
Remove the laser/scanner assembly (Y/M) ................................................ 186
Laser/scanner assembly (C/Bk) .............................................................................. 193
Remove the laser/scanner assembly (C/Bk) ............................................... 194
Reinstall the protective glass cleaner (PGC) actuators ................... 198
High voltage power supply upper (HVPS-T) .............................................................. 201
Remove the high voltage power supply upper ............................................ 202
Reinstall the high voltage power supply upper ............................ 205
Drum motor 1 ....................................................................................................... 206
Remove the drum motor 1 ....................................................................... 207
Drum motor 2 or drum motor 3 ............................................................................... 208
Remove the drum motor 2 or drum motor 3 ............................................... 209
Fuser motor .......................................................................................................... 210
Remove the fuser motor ........................................................................... 211
Main drive assembly ............................................................................................. 212
Remove the main drive assembly .............................................................. 213
Reinstall the main drive assembly .............................................. 217
Fuser drive assembly ............................................................................................. 223
Remove the fuser drive assembly .............................................................. 224
Reinstall the fuser drive assembly ............................................... 2
Delivery assembly ................................................................................................. 228
Remove the delivery assembly .................................................................. 229
Reinstall the delivery assembly .................................................. 232
Duplex drive assembly ........................................................................................... 233
Remove the duplex drive assembly ........................................................... 234
Optional paper feeder assembly (Tray 3) ................................................................................ 235
Drawer connector ................................................................................................. 235
27
ENWW ix
3 Solve problems ............................................................................................................. 237
Solve problems checklist ....................................................................................................... 238
Menu map .......................................................................................................................... 240
Current settings pages .......................................................................................................... 241
Preboot menu options ........................................................................................................... 242
Troubleshooting process ........................................................................................................ 243
Determine the problem source ................................................................................. 243
Troubleshooting flowchart ....................................................................... 243
Power subsystem ................................................................................................... 244
Power-on checks .................................................................................... 244
Power-on troubleshooting overview ............................................ 244
Tools for troubleshooting ....................................................................................................... 246
Individual component diagnostics ............................................................................ 246
LED diagnostics ...................................................................................... 246
Understand lights on the formatter ............................................. 246
Engine diagnostics ................................................................................. 254
Defeating interlocks ................................................................. 254
Disable cartridge check ........................................................... 256
Engine test button .................................................................... 257
Paper path test ....................................................................................... 258
Paper path sensors test ........................................................................... 258
Manual sensor test ................................................................................. 260
Registration sensor .................................................................. 261
Fuser loop sensors ................................................................... 262
Fuser output sensor .................................................................. 263
Duplexer refeed sensor ............................................................ 264
Output-bin full sensor ............................................................... 265
Fuser pressure-release sensor .................................................... 266
ITB alienation sensor ................................................................ 267
Right- and front-door interlock switches ....................................... 269
Tray/bin manual sensor test ..................................................... 271
Print/stop test ........................................................................................ 279
Component tests ..................................................................................... 280
Compo
Diagrams ............................................................................................................. 282
Block diagrams ...................................................................................... 282
Location of connectors ............................................................................ 284
DC controller PCA ................................................................... 284
Paper feeder driver PCA .......................................................... 285
Plug/jack locations ................................................................................. 286
Locations of major components ................................................................ 286
nent test (special-mode test) ............................................ 280
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Base product .......................................................................... 286
1 x 500 paper feeder .............................................................. 293
General timing chart ............................................................................... 294
Circuit diagrams .................................................................................... 295
Internal print-quality test pages ................................................................................ 297
Print quality troubleshooting pages ........................................................... 297
Print quality assessment page .................................................................. 300
Cleaning page ....................................................................................... 302
Set up an auto cleaning page ................................................... 302
Configuration page ................................................................................ 303
Configuration page ................................................................. 303
HP embedded Jetdirect page .................................................... 305
Finding important information on the configuration pages ............ 306
Color band test ...................................................................................... 307
Print quality troubleshooting tools ............................................................................ 308
Repetitive defects ruler ............................................................................ 308
Calibrate the product .............................................................................. 309
Control panel menus .............................................................................................. 310
Sign In menu ......................................................................................... 310
Retrieve Job From USB menu ................................................................... 311
Retrieve Job From Device Memory menu ................................................... 312
Supplies menu ....................................................................................... 316
Trays menu ............................................................................................ 324
Administration menu ............................................................................... 329
Reports menu .......................................................................... 329
General Settings menu ............................................................. 331
Retrieve From USB Settings menu .............................................. 349
General Print Settings menu ...................................................... 349
Default Print Options menu ....................................................... 352
Display Settings menu .............................................................. 355
Manage Supplies menu ........................................................... 356
Manage Trays menu ................................................................ 363
Network Settings menu ............................................................ 365
Troubleshooting menu ............................................................................. 382
Device Maintenance menu ...................................................................... 38
Backup/Restore menu .............................................................. 388
Calibrate/Cleaning menu ........................................................ 388
USB Firmware Upgrade menu ................................................... 391
Interpret control panel messages, status-alert messages, and event code errors ............. 392
10.0X.Y0 Supply memory error ............................................................... 392
10.22.50 .............................................................................................. 393
8
ENWW xi
10.22.51 .............................................................................................. 393
10.22.52 .............................................................................................. 393
10.23.50 .............................................................................................. 393
10.23.51 .............................................................................................. 394
10.23.52 .............................................................................................. 394
10.23.60 .............................................................................................. 394
10.23.70 Printing past very low .............................................................. 394
10.XX.34 Used supply in use ................................................................... 395
10.XX.40 Genuine HP supplies installed ................................................... 395
10.XX.41 Unsupported supply in use ........................................................ 396
10.XX.70 Printing past very low ............................................................... 396
10.YY.15 Install <supply> ....................................................................... 397
10.YY.25 Wrong cartridge in <color> slot ................................................ 397
10.YY.35 Incompatible <supply> ............................................................. 398
11.00.YY Internal clock error .................................................................. 399
13.00.00 .............................................................................................. 399
13.A3.D3 ............................................................................................. 399
13.A3.FF .............................................................................................. 399
13.B2.9C ............................................................................................. 399
13.B2.A1 ............................................................................................. 400
13.B2.A2 ............................................................................................. 400
13.B2.A3 ............................................................................................. 400
13.B2.D1 .............................................................................................. 400
13.B2.D2 .............................................................................................. 400
13.B2.D3 .............................................................................................. 400
13.D3.DZ ............................................................................................. 401
13.WX.EE ............................................................................................. 401
13.WX.FF ............................................................................................. 401
13.WX.YZ Fuser area jam ...................................................................... 402
13.WX.YZ Fuser wrap jam ...................................................................... 403
13.WX.YZ Jam below control panel ......................................................... 404
13.WX.YZ Jam in middle right door ......................................................... 404
13.WX.YZ Jam in right door .................................................................... 405
13.WX.YZ Jam in Tray 1 ........................................................................ 4
13.WX.YZ Jam in Tray <X> ..................................................................... 406
20.00.00 Insufficient memory To continue, press OK .................................. 406
21.00.00 Page too complex ................................................................... 406
32.08.XX .............................................................................................. 407
32.1C.XX .............................................................................................. 407
32.21.00 .............................................................................................. 411
33.XX.YY .............................................................................................. 412
05
xii ENWW
33.XX.YY Used board/disk ..................................................................... 412
41.02.00 Error ...................................................................................... 412
41.03.YZ Unexpected size in tray <X> ..................................................... 413
41.05.YZ Unexpected type in tray <X> .................................................... 413
41.07.YZ Error To continue, press OK ...................................................... 415
42.XX.YY .............................................................................................. 417
47.00.XX .............................................................................................. 417
47.01.XX .............................................................................................. 417
47.02.XX .............................................................................................. 417
47.03.XX .............................................................................................. 418
47.04.XX .............................................................................................. 418
47.05.00 .............................................................................................. 418
47.06.XX .............................................................................................. 418
47.WX.YZ Printer calibration error To continue, press OK ........................... 418
49.XX.YY To continue, turn off then on ...................................................... 420
50.WX.YZ Fuser error To continue, turn off then on .................................... 421
51.00.YY Error ...................................................................................... 424
52.00.XX To continue, turn off then on ...................................................... 424
54.XX.YY Error ...................................................................................... 425
55.00.YY DC controller error To continue, turn off then on .......................... 427
55.0X.YY DC controller error To continue, turn off then on .......................... 427
56.00.YY Error To continue, turn off then on .............................................. 427
57.00.0Y Error To continue, turn off then on ............................................. 428
58.00.04 .............................................................................................. 428
59.00.YY Error To continue, turn off then on .............................................. 429
59.05.XX .............................................................................................. 429
60.00.0Y Tray <Y> lifting error ............................................................... 430
61.00.01 .............................................................................................. 431
62.00.00 No system To continue, turn off then on ...................................... 431
70.00.00 Error To continue, turn off then on ............................................. 431
81.0X.YY Embedded JetDirect error ......................................................... 432
98.00.01 Corrupt data in firmware volume ............................................... 432
98.00.02 Corrupt data in solutions volume ............................................... 433
98.00.03 Corrupt data in configuration volume ......................................... 433
98.00.04 Corrupt data in job data volume ............................................... 433
99.00.01 Upgrade not performed file is corrupt ........................................ 433
99.00.02 Upgrade not performed timeout during receive ........................... 434
99.00.03 Upgrade not performed error writing to disk ............................... 434
99.00.04 Upgrade not performed timeout during receive ........................... 434
99.00.05 Upgrade not performed timeout during receive ........................... 434
99.00.06 Upgrade not performed error reading upgrade ........................... 435
ENWW xiii
99.00.07 Upgrade not performed error reading upgrade ........................... 435
99.00.08 Upgrade not performed error reading upgrade ........................... 435
99.00.09 Upgrade canceled by user ....................................................... 435
99.00.10 Upgrade canceled by user ....................................................... 436
99.00.11 Upgrade canceled by user ....................................................... 436
99.00.12 Upgrade not performed the file is invalid ................................... 436
99.00.13 Upgrade not performed the file is invalid ................................... 436
99.00.14 Upgrade not performed the file is invalid ................................... 437
99.00.2X .............................................................................................. 437
99.09.60 Unsupported disk .................................................................... 438
99.09.61 Unsupported disk .................................................................... 438
99.09.62 Unknown disk ......................................................................... 438
99.09.63 Incorrect disk .......................................................................... 438
99.09.64 Disk malfunction ...................................................................... 438
99.09.65 Disk data error ........................................................................ 439
99.09.66 No disk data installed .............................................................. 439
99.09.67 Disk is not bootable please download firmware .......................... 439
99.XX.YY .............................................................................................. 439
99.XX.YY .............................................................................................. 440
<Binname> Full Remove all paper from bin ............................................... 440
<Supply> almost full ............................................................................... 440
<Supply> low OR Supplies low ................................................................ 440
<Supply> very low OR Supplies very low .................................................. 441
<Tray X> lifting ...................................................................................... 442
[File System] device failure To clear, press OK ........................................... 442
[File System] file operation failed To clear, press OK .................................. 442
[File System] file system is full To clear, press OK ....................................... 442
[File System] is not initialized ................................................................... 443
[File System] is write protected ................................................................. 443
Accept bad signature ............................................................................. 443
Bad optional tray connection ................................................................... 443
Calibration reset pending ........................................................................ 444
Canceling ............................................................................................. 444
Canceling... <jobname> ......................................................................... 444
Checking engine .................................................................................... 444
Checking paper path .............................................................................. 444
osen personality not available To continue, press OK ............................. 445
Ch
Cleaning do not grab paper .................................................................... 445
Cleaning... ............................................................................................ 445
Clearing event log .................................................................................. 445
Clearing paper path ............................................................................... 445
xiv ENWW
Close front door ..................................................................................... 446
Close lower right door ............................................................................ 446
Close upper right door ............................................................................ 446
Creating cleaning page .......................................................................... 446
Data received To print last page, press OK ............................................... 447
EIO <X> disk initializing ......................................................................... 447
Event log is empty .................................................................................. 447
Expected drive missing ........................................................................... 447
HP Secure Hard Drive disabled ................................................................ 447
Incompatible <supply> ............................................................................ 448
Incompatible supplies ............................................................................. 448
Install <supply> ...................................................................................... 449
Install <supply> Close rear door .............................................................. 449
Install Fuser Unit ..................................................................................... 449
Install supplies ....................................................................................... 450
Install Transfer Unit ................................................................................. 450
Internal disk not functional ....................................................................... 450
Internal disk spinning up ......................................................................... 451
Load Tray <X>: [Type], [Size] .................................................................. 451
Load Tray <X>: [Type], [Size] To use another tray, press OK ....................... 451
Manually feed output stack Then press OK to print second sides .................. 452
Manually feed: [Type], [Size] ................................................................... 452
Manually feed: [Type], [Size] To use another tray, press OK ....................... 452
Moving solenoid .................................................................................... 452
Moving solenoid and motor ..................................................................... 453
No job to cancel .................................................................................... 453
Paused .................................................................................................. 453
Performing Color Band Test... .................................................................. 453
Performing Paper Path Test... ................................................................... 453
Please wait... ......................................................................................... 454
Printing CMYK samples... ........................................................................ 454
Printing Color Usage Log... ..................................................................... 454
Printing Configuration... .......................................................................... 454
Printing Demo Page... ............................................................................. 454
Printing Diagnostics Page... ..................................................................... 454
Printing Engine Test... ............................................................................. 455
Printing Event Log... ................................................................................ 455
Printing File Directory... ........................................................................... 455
Printing Font List... .................................................................................. 455
inting Fuser Test Page... ....................................................................... 455
Pr
Printing Help Page... .............................................................................. 456
ENWW xv
Printing Menu Map... ............................................................................. 456
Printing PQ Troubleshooting... ................................................................. 456
Printing Registration Page... ..................................................................... 456
Printing RGB Samples... .......................................................................... 456
Printing stopped ..................................................................................... 456
Printing Supplies Status Page... ................................................................ 457
Printing Usage Page... ............................................................................ 457
Processing duplex job Do not grab paper until job completes ...................... 457
Processing job from tray <X>... Do not grab paper until job completes ......... 457
Processing... .......................................................................................... 457
Processing... copy <X> of <Y> ................................................................ 458
Ready ................................................................................................... 458
Ready <IP Address> ............................................................................... 458
Remove all print cartridges ...................................................................... 458
Remove at least one print cartridge .......................................................... 458
Remove shipping lock from Tray 2 ............................................................ 459
Replace <supply> .................................................................................. 459
Replace Supplies .................................................................................... 460
Restore Factory Settings .......................................................................... 461
Restricted from printing in color ................................................................ 461
Rotating <color> motor ........................................................................... 461
Rotating motor ....................................................................................... 461
Size mismatch in Tray <X> ...................................................................... 462
Sleep mode on ...................................................................................... 462
Supplies in wrong positions ..................................................................... 462
Tray <X> empty: [Type], [Size] ................................................................ 463
Tray <X> open ....................................................................................... 463
Tray <X> overfilled ................................................................................. 464
Troubleshooting ..................................................................................... 464
Type mismatch Tray <X> ......................................................................... 464
Unsupported drive installed To continue, press OK ..................................... 464
Unsupported supply in use OR Unsupported supply installed To continue,
press OK ............................................................................................... 465
Unsupported tray configuration ................................................................ 465
Unsupported USB accessory detected Remove USB accessory ...................... 465
USB accessory needs too much power Remove USB and turn off then on ...... 466
USB accessory not functional ................................................................... 4
Used supply installed To continue, press OK OR Used supply in use ............. 466
Wrong cartridge in <color> slot ............................................................... 467
Event log messages ............................................................................................... 468
Print an event log ................................................................................... 469
66
xvi ENWW
View an event log .................................................................................. 470
Clear an event log .................................................................................. 470
Clear jams .......................................................................................................................... 471
Common causes of jams ........................................................................................ 471
Jam locations ........................................................................................................ 472
Clear jams in Tray 1 .............................................................................................. 473
Clear jams in the output bin area ............................................................................ 475
Clear jams in Tray 2 .............................................................................................. 476
Clear jams in the right door .................................................................................... 477
Clear jams in the optional 500-sheet paper and heavy media tray (Tray 3) .................. 481
Clear jams in the lower right door (Tray 3) ............................................................... 482
Jam causes and solutions ....................................................................................... 483
Jams in the output bin ............................................................................. 483
Jams in the fuser and transfer area ........................................................... 483
Jams in the duplex area (duplex models) ................................................... 487
Jams in Tray 1, Tray 2 and internal paper path .......................................... 488
Jams in Tray 3 ....................................................................................... 490
Change jam recovery ............................................................................................ 491
Solve paper handling problems ............................................................................................. 492
Product feeds multiple sheets .................................................................................. 492
Paper does not feed automatically ........................................................................... 492
Use manual print modes ....................................................................................................... 494
Solve image quality problems ................................................................................................ 497
Image defects table ............................................................................................... 497
Clean the product ................................................................................................................ 503
Clean the paper path ............................................................................................ 503
Set up an auto cleaning page .................................................................. 503
Solve performance problems ................................................................................................. 504
Solve connectivity problems ................................................................................................... 505
lve direct connect problems ................................................................................ 505
So
Solve network problems ......................................................................................... 505
Service mode functions ......................................................................................................... 507
Service menu ........................................................................................................ 507
Product resets ....................................................................................................... 509
Restore factory-set defaults ....................................................................... 509
Product cold reset ................................................................................... 510
Clean Disk and Partial Clean functions .................................................................... 510
Active and repository firmware locations ................................................... 510
Partial Clean ......................................................................................... 511
Execute a Partial Clean ............................................................ 511
Clean Disk ............................................................................................ 512
ENWW xvii
Execute a Clean Disk ............................................................... 512
Preboot menu options ........................................................................................................... 514
Product updates ................................................................................................................... 521
Determine the installed revision of firmware .............................................................. 521
Perform a firmware upgrade ................................................................................... 521
Embedded Web Server ........................................................................... 521
USB storage device (Preboot menu) .......................................................... 522
USB storage device (control-panel menu) ................................................... 523
4 Parts and diagrams ...................................................................................................... 525
Order parts, accessories, and supplies ................................................................................... 526
Part numbers ....................................................................................................................... 527
Accessories .......................................................................................................... 527
Print cartridges and toner collection unit ................................................................... 527
Memory ............................................................................................................... 527
Customer self repair (CSR) and service kits ............................................................... 528
Screws ................................................................................................................................ 530
How to use the parts lists and diagrams .................................................................................. 530
Covers ................................................................................................................................ 532
............................................................................................................................ 532
Right-door assembly ............................................................................................................. 534
Internal assemblies ............................................................................................................... 536
Internal assemblies (1 of 5) ..................................................................................... 536
Internal assemblies (2 of 5) ..................................................................................... 538
Internal assemblies (3 of 5) ..................................................................................... 540
Internal assemblies (4 of 5) ..................................................................................... 542
Internal assemblies (5 of 5) ..................................................................................... 544
Cassette ............................................................................................................... 546
Paper pickup assembly .......................................................................................... 548
PCAs ................................................................................................................... 550
Assessories .......................................................................................................................... 552
1 x 500-sheet paper feeder .................................................................................... 552
Paper feeder covers ............................................................................................... 554
feeder main body ........................................................................................ 556
Paper
Paper feeder cassette ............................................................................................. 558
Paper feeder PCA ................................................................................................. 560
Alphabetical parts list ........................................................................................................... 562
Numerical parts list .............................................................................................................. 568
Appendix A Service and support ..................................................................................... 575
Hewlett-Packard limited warranty statement ............................................................................. 576
xviii ENWW
HP's Premium Protection Warranty: LaserJet print cartridge limited warranty statement .................. 578
Color LaserJet Fuser Kit, Toner Collection Unit, and Transfer Kit Limited Warranty Statement .......... 579
Data stored on the print cartridge ........................................................................................... 580
End User License Agreement .................................................................................................. 581
OpenSSL ............................................................................................................................. 584
Customer self-repair warranty service ..................................................................................... 585
Customer support ................................................................................................................. 586
Appendix B Product specifications ................................................................................... 587
Physical specifications .......................................................................................................... 588
Power consumption, electrical specifications, and acoustic emissions .......................................... 588
Environmental specifications .................................................................................................. 588
Appendix C Regulatory information ................................................................................. 589
FCC regulations ................................................................................................................... 590
Environmental product stewardship program ........................................................................... 591
Protecting the environment ...................................................................................... 591
Ozone production ................................................................................................. 591
Power consumption ............................................................................................... 591
Paper use ............................................................................................................. 591
Plastics ................................................................................................................. 591
HP LaserJet print supplies ....................................................................................... 591
Return and recycling instructions ............................................................................. 592
United States and Puerto Rico .................................................................. 592
Multiple returns (more than one cartridge) .................................. 592
Single returns .......................................................................... 592
Shipping ................................................................................ 592
Non-U.S. returns .................................................................................... 593
Paper .................................................................................................................. 593
Material restrictions ............................................................................................... 593
Disposal of waste equipment by users in private households in the European Union ...... 594
Chemical substances ............................................................................................. 594
Material Safety Data Sheet (MSDS) ......................................................................... 594
For more information ............................................................................................. 594
Declaration of conformity ...................................................................................................... 5
Certificate of volatility ........................................................................................................... 597
Types of memory ................................................................................................... 597
Volatile memory ..................................................................................... 597
Non-volatile memory .............................................................................. 597
Mass Storage memory ............................................................................ 597
Safety statements ................................................................................................................. 598
9
5
ENWW xix
Laser safety .......................................................................................................... 598
Canadian DOC regulations .................................................................................... 598
VCCI statement (Japan) .......................................................................................... 598
Power cord instructions .......................................................................................... 598
Power cord statement (Japan) ................................................................................. 598
EMC statement (Korea) .......................................................................................... 599
Laser statement for Finland ..................................................................................... 599
GS statement (Germany) ........................................................................................ 600
Substances Table (China) ....................................................................................... 600
Restriction on Hazardous Substances statement (Turkey) ............................................. 600
Restriction on Hazardous Substances statement (Ukraine) ........................................... 600
Index ............................................................................................................................... 601
xx ENWW
List of tables
Table 1-1 Sequence of operation ............................................................................................................ 3
Table 1-2 Solenoids .............................................................................................................................. 6
Table 1-3 Clutches ................................................................................................................................ 6
Table 1-4 Switches ................................................................................................................................ 6
Table 1-5 Sensors ................................................................................................................................. 7
Table 1-6 Motors .................................................................................................................................. 8
Table 1-7 Fans ..................................................................................................................................... 9
Table 1-8 High voltage power supply circuits ......................................................................................... 10
Table 1-9 Converted DC voltages ......................................................................................................... 13
Table 1-10 Fuser components ............................................................................................................... 15
Table 1-11 Image formation process ..................................................................................................... 22
Table 1-12 Primary-transfer-roller engagement states ............................................................................... 32
Table 1-13 Image-stabilization controls .................................................................................................. 37
Table 1-14 Switches and sensors for the pickup, feed, and delivery system (1 of 2) .................................... 38
Table 1-15 Switches and sensors for the pickup, feed, and delivery system (2 of 2) .................................... 39
Table 1-16 Motors and solenoids for the pickup, feed, and delivery system ............................................... 40
Table 1-17 Jams that the product detects ............................................................................................... 57
Table 1-18 Electr
Table 1-19 Paper size detection ........................................................................................................... 62
Table 3-1 Troubleshooting flowchart .................................................................................................... 243
Table 3-2 Heartbeat LED, product initialization ..................................................................................... 247
Table 3-3 Heartbeat LED, product operational ...................................................................................... 249
Table 3-4 Connectivity LED, product initialization .................................................................................. 251
Table 3-5 Connectivity LED, product operational ................................................................................... 253
Table 3-6 Paper-path sensors diagnostic tests ....................................................................................... 259
Table 3-7 Manual sensor diagnostic tests ............................................................................................. 260
Table 3-8 Manual sensor test 2 diagnostic tests .................................................................................... 271
Table 3-9 Component test details ........................................................................................................ 280
Table 3-10 Sensors ........................................................................................................................... 282
Table 3-11 DC controller connectors ................................................................................................... 284
Table 3-12 Paper feeder driver PCA connectors ................................................................................... 285
Table 3-13 PCAs, motors, fans, switches, solenoids, and clutches ........................................................... 291
ical components for the paper feeder ............................................................................ 60
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Table 3-14 Important information on the configuration pages ................................................................. 306
Table 3-15 Sign In menu .................................................................................................................. 310
Table 3-16 Retrieve Job From USB menu ....................................................................................... 311
Table 3-17 Retrieve Job From Device Memory menu ................................................................... 312
Table 3-18 Supplies menu ............................................................................................................... 316
Table 3-19 Trays menu .................................................................................................................... 324
Table 3-20 Reports menu ................................................................................................................ 329
Table 3-21 General Settings menu ................................................................................................. 331
Table 3-22 Retrieve From USB Settings menu ............................................................................... 349
Table 3-23 General Print Settings menu .......................................................................................... 349
Table 3-24 Default Print Options menu .......................................................................................... 352
Table 3-25 Display Settings menu .................................................................................................. 355
Table 3-26 Manage Supplies menu ................................................................................................ 356
Table 3-27 Manage Trays menu ..................................................................................................... 363
Table 3-28 Network Settings menu ................................................................................................ 365
Table 3-29 Jetdirect Menu ............................................................................................................. 365
Table 3-30 Troubleshooting menu .................................................................................................. 382
Table 3-31 Backup/Restore menu .................................................................................................. 388
Table 3-32 Calibrate/Cleaning menu ............................................................................................. 388
Table 3-33 Causes an
Table 3-34 Causes and solutions for fuser delivery delay jams ............................................................... 483
Table 3-35 Causes and solutions for wrapping jams ............................................................................. 484
Table 3-36 Causes and solutions for fuser delivery stationary jams .......................................................... 484
Table 3-37 Causes and solutions for residual media jams ...................................................................... 484
Table 3-38 Causes and solutions for pickup delay jams 2 ...................................................................... 485
Table 3-39 Causes and solutions for pickup stationary jams ................................................................... 486
Table 3-40 Causes and solutions for duplexing reverse jams .................................................................. 487
Table 3-41 Causes and solutions for duplex repick jams ........................................................................ 487
Table 3-42 Causes and solutions for residual media jams ...................................................................... 488
Table 3-43 Causes and solutions for pickup delay jam 1: tray pickup ..................................................... 488
Table 3-44 Causes and solutions for pickup stationary jams ................................................................... 489
Table 3-45 Causes and solutions for pickup delay jam 1; MP tray pickup ................................................ 489
Table 3-46 Causes and solutions for pickup delay and pickup stationary jams ......................................... 490
Table 3-47 Print modes under the Adjust Paper Types sub menu ....................................................... 494
Table 3-48 MP modes under the Optimize submenu ........................................................................... 4
Table 3-49 Image defects table .......................................................................................................... 497
Table 3-50 Solve performance problems .............................................................................................. 504
Table 3-51 Preboot menu options (1 of 5) ............................................................................................ 514
Table 3-52 Preboot menu options (2 of 5) ............................................................................................ 516
Table 3-53 Preboot menu options (3 of 5) ............................................................................................ 517
Table 3-54 Preboot menu options (4 of 5) ............................................................................................ 518
d solutions for delivery delay jam ........................................................................ 483
95
xxii ENWW
Table 3-55 Preboot menu options (5 of 5) ............................................................................................ 519
Table 3-56 Preboot menu options (5 of 5) ............................................................................................ 520
Table 4-1 Common fasteners ............................................................................................................. 530
Table 4-2 External covers, panels, and doors ....................................................................................... 533
Table 4-3 Right-door assembly ............................................................................................................ 535
Table 4-4 Internal assemblies (1 of 5) .................................................................................................. 537
Table 4-5 Internal assemblies (2 of 5) .................................................................................................. 539
Table 4-6 Internal assemblies (3 of 5) .................................................................................................. 541
Table 4-7 Internal assemblies (4 of 5) .................................................................................................. 543
Table 4-8 Internal assemblies (5 of 5) .................................................................................................. 545
Table 4-9 Cassette ............................................................................................................................ 547
Table 4-10 Paper pickup assembly ..................................................................................................... 549
Table 4-11 PCAs .............................................................................................................................. 551
Table 4-12 1 x 500-sheet paper feeder ............................................................................................... 553
Table 4-13 Paper feeder covers .......................................................................................................... 555
Table 4-14 Paper feeder main body .................................................................................................... 557
Table 4-15 Cassette .......................................................................................................................... 559
Table 4-16 Paper feeder PCA ............................................................................................................ 561
Table 4-17 Alphabetical parts list ....................................................................................................... 562
Table 4-18 Numerical parts list ........................................................................................................... 56
Table B-1 Product dimensions ............................................................................................................. 588
Table B-2 Product dimensions, with all doors and trays fully opened ....................................................... 588
8
ENWW xxiii
xxiv ENWW
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 ................................................................................................................ 15
Figure 1-7 Fuser temperature control circuit ............................................................................................ 16
Figure 1-8 Laser/scanner system ........................................................................................................... 19
Figure 1-9 Image formation system ........................................................................................................ 21
Figure 1-10 Image formation process .................................................................................................... 22
Figure 1-11 Pre-exposure ..................................................................................................................... 23
Figure 1-12 Primary charging ............................................................................................................... 23
Figure 1-13 Laser-beam exposure ......................................................................................................... 24
Figure 1-14 Development ..................................................................................................................... 24
Figure 1-15 Primary transfer ................................................................................................................. 25
Figure 1-16 Secondary transfer ............................................................................................................ 25
Figure 1-17 Separation ....................................................................................................................... 26
Figure 1-18 Fusing .............................................................................................................................. 26
Figure 1-19 ITB cleaning ...................................................................................................................... 27
Figure 1-20 Drum cleaning .................................................................................................................. 27
Figure 1-21 Print-cartridge system ......................................
Figure 1-22 Developing-roller engagement and disengagement control ..................................................... 29
Figure 1-23 ITB unit ............................................................................................................................. 31
Figure 1-24 Three states of primary-transfer-roller engagement and disengagement ..................................... 33
Figure 1-25 ITB cleaning process .......................................................................................................... 35
Figure 1-26 Toner patterns for calibration .............................................................................................. 36
Figure 1-27 Switches and sensors for the pickup, feed, and delivery system (1 of 2) ................................... 38
Figure 1-28 Switches and sensors for the pickup, feed, and delivery system (2 of 2) ................................... 39
Figure 1-29 Motors and solenoids for the pickup, feed, and delivery system .............................................. 40
Figure 1-30 Three main units of the pickup, feed, and delivery system ....................................................... 41
Figure 1-31 Pick feed mechanism ......................................................................................................... 42
Figure 1-32 Cassette-pickup mechanism ................................................................................................ 43
................................................................... 28
ENWW xxv
Figure 1-33 Cassette presence sensor .................................................................................................... 44
Figure 1-34 Cassette lift mechanism ...................................................................................................... 45
Figure 1-35 Paper level detection mechanism ......................................................................................... 46
Figure 1-36 Cassette media width detection ........................................................................................... 47
Figure 1-37 Multifeed prevention .......................................................................................................... 48
Figure 1-38 Multipurpose tray pickup mechanism ................................................................................... 49
Figure 1-39 Paper-feed mechanism ....................................................................................................... 50
Figure 1-40 Skew-feed prevention ......................................................................................................... 51
Figure 1-41 Fuser and delivery unit ....................................................................................................... 52
Figure 1-42 Loop-control mechanism ..................................................................................................... 53
Figure 1-43 Pressure-roller pressurization control .................................................................................... 54
Figure 1-44 Duplexing unit ................................................................................................................... 55
Figure 1-45 Jam detection sensors ........................................................................................................ 57
Figure 1-46 Optional paper feeder ....................................................................................................... 59
Figure 1-47 Signals for the paper feeder ............................................................................................... 60
Figure 1-48 Paper-feeder pickup and feed operation ............................................................................... 61
Figure 1-49 Paper size detection .......................................................................................................... 62
Figure 1-50 Paper-feeder cassette lift ..................................................................................................... 64
Figure 1-51 Paper
Figure 1-52 Jam detection .................................................................................................................... 68
Figure 2-1 Phillips and pozidrive screwdriver comparison ........................................................................ 72
Figure 2-2 Parts removal order (1 of 2) .................................................................................................. 74
Figure 2-3 Parts removal order (2 of 2) .................................................................................................. 75
Figure 2-4 Remove the print cartridge (1 of 2) ........................................................................................ 76
Figure 2-5 Remove the print cartridge (2 of 2) ........................................................................................ 77
Figure 2-6 Remove the duplex reverse guide (1 of 2) ............................................................................... 78
Figure 2-7 Remove the duplex reverse guide (2 of 2) ............................................................................... 78
Figure 2-8 Remove the toner collection unit (1 of 4) ................................................................................. 79
Figure 2-9 Remove the toner collection unit (2 of 4) ................................................................................. 79
Figure 2-10 Remove the toner collection unit (3 of 4) ............................................................................... 80
Figure 2-11 Remove the toner collection unit (4 of 4) ............................................................................... 80
Figure 2-12 Remove the formatter ......................................................................................................... 81
Figure 2-13 Remove the HDD (1 of 2) ................................................................................................... 82
Figure 2-14 Remove the HDD (2 of 2) ................................................................................................... 83
Figure 2-15 Remove the SSM (1 of 2) .................................................................................................... 84
Figure 2-16 Remove the SSM (2 of 2) .................................................................................................... 84
Figure 2-17 Remove the tray cassette (1 of 2) ......................................................................................... 86
Figure 2-18 Remove the tray cassette (2 of 2) ......................................................................................... 86
Figure 2-19 Remove the fuser
Figure 2-20 Remove the fuser (2 of 2) ................................................................................................... 87
Figure 2-21 Remove the pickup roller (Tray 1; 1 of 2) ............................................................................. 88
-feeder multiple feed prevention .................................................................................. 67
(1 of 2) ................................................................................................... 87
xxvi ENWW
Figure 2-22 Remove the pickup roller (Tray 1; 2 of 2) ............................................................................. 88
Figure 2-23 Remove the pickup roller (Tray 2; 1 of 4) ............................................................................. 89
Figure 2-24 Remove the pickup roller (Tray 2; 2 of 4) ............................................................................. 89
Figure 2-25 Remove the pickup roller (Tray 2; 3 of 4) ............................................................................. 90
Figure 2-26 Remove the pickup roller (Tray 2; 4 of 4) ............................................................................. 90
Figure 2-27 Remove the Pickup and feed rollers (Tray 3; 1 of 2) ............................................................... 91
Figure 2-28 Remove the Pickup and feed rollers (Tray 3; 2 of 2) ............................................................... 92
Figure 2-29 Remove the separation roller (Tray 2) ................................................................................... 93
Figure 2-30 Remove the transfer roller (1 of 3) ....................................................................................... 94
Figure 2-31 Remove the transfer roller (2 of 3) ....................................................................................... 94
Figure 2-32 Remove the transfer roller (3 of 3) ....................................................................................... 95
Figure 2-33 Reinstall the transfer roller ................................................................................................... 95
Figure 2-34 Remove the secondary transfer assembly (1 of 3) .................................................................. 96
Figure 2-35 Remove the secondary transfer assembly (2 of 3) .................................................................. 96
Figure 2-36 Remove the secondary transfer assembly (3 of 3) .................................................................. 97
Figure 2-37 Reinstall the secondary transfer assembly ............................................................................. 97
Figure 2-38 Remove the intermediate transfer belt (1 of 3) ....................................................................... 98
Figure 2-39 Remove the intermediate transfer belt (2 of 3) ....................................................................... 98
Figure 2-40 Remove the intermediate transfer belt (3 of 3) ....................................................................... 99
Figure 2-41 Remove the right door; optional paper feeder (1 of 3) ......................................................... 100
Figure 2-42 Remove the right door; optional paper feeder (2 of 3)
Figure 2-43 Remove the right door; optional paper feeder (3 of 3) ......................................................... 101
Figure 2-44 External panels, covers, and doors; identification and location ............................................. 102
Figure 2-45 Remove the front door assembly (1 of 2) ............................................................................ 103
Figure 2-46 Remove the front door assembly (2 of 2) ............................................................................ 104
Figure 2-47 Remove the right door assembly (1 of 8) ............................................................................ 105
Figure 2-48 Remove the right door assembly (2 of 8) ............................................................................ 105
Figure 2-49 Remove the right door assembly (3 of 8) ............................................................................ 106
Figure 2-50 Remove the right door assembly (4 of 8) ............................................................................ 106
Figure 2-51 Remove the right door assembly (5 of 8) ............................................................................ 107
Figure 2-52 Remove the right door assembly (6 of 8) ............................................................................ 107
Figure 2-53 Remove the right door assembly (7 of 8) ............................................................................ 108
Figure 2-54 Remove the right door assembly (8 of 8) ............................................................................ 108
Figure 2-55 Remove the right rear cover (1 of 3) .................................................................................. 109
Figure 2-56 Remove the right rear cover (2 of 3) .................................................................................. 109
Figure 2-57 Remove the right rear cover (3 of 3) .................................................................................. 110
Figure 2-58 Remove the left cover (1 of 4) ........................................................................................... 111
Figure 2-59 Remove the left cover (2 of 4) ........................................................................................... 111
Figure 2-60 Remove the left cover (3 of 4) ........................................................................................... 112
Figure 2-61 Remove the l
Figure 2-62 Remove the left bottom cover ............................................................................................ 113
eft cover (4 of 4) ........................................................................................... 112
......................................................... 100
ENWW xxvii
Figure 2-63 Remove the left bottom handle .......................................................................................... 114
Figure 2-64 Remove the HIP (1 of 2) ................................................................................................... 115
Figure 2-65 Remove the HIP (2 of 2) ................................................................................................... 115
Figure 2-66 Remove the control panel assembly (1 of 4) ........................................................................ 116
Figure 2-67 Remove the control panel assembly (2 of 4) ........................................................................ 116
Figure 2-68 Remove the control panel assembly (3 of 4) ........................................................................ 117
Figure 2-69 Remove the control panel assembly (4 of 4) ........................................................................ 117
Figure 2-70 Remove the right front cover (1 of 5) .................................................................................. 118
Figure 2-71 Remove the right front cover (2 of 5) .................................................................................. 119
Figure 2-72 Remove the right front cover (3 of 5) .................................................................................. 119
Figure 2-73 Remove the right front cover (4 of 5) .................................................................................. 120
Figure 2-74 Remove the right front cover (5 of 5) .................................................................................. 120
Figure 2-75 Reinstall the power button ................................................................................................. 121
Figure 2-76 Remove the front top cover (1 of 2) .................................................................................... 122
Figure 2-77 Remove the front top cover (2 of 2) .................................................................................... 123
Figure 2-78 Remove the rear cover and upper rear cover (1 of 4) ........................................................... 124
Figure 2-79 Remove the rear cover and upper rear cover (2 of 4) ........................................................... 125
Figure 2-80 Remove the rear cover and upper rear cover (3 of 4) ........................................................... 125
Figure 2-81 Remove the rear cover and upper rear cover (4 of 4) ........................................................... 126
Figure 2-82 Remove the rear top cover (1 of 2) .................................................................................... 12
Figure 2-83 Remove the rear top cover (2 of 2) .................................................................................... 128
Figure 2-84 Remove the right bottom handle ........................................................................................ 129
Figure 2-85 Remove the rear bottom handle ......................................................................................... 130
Figure 2-86 Remove the delivery fan, cartridge fan, and environmental sensor (1 of 9) ............................. 131
Figure 2-87 Remove the delivery fan, cartridge fan, and environmental sensor (2 of 9) ............................. 132
Figure 2-88 Remove the delivery fan, cartridge fan, and environmental sensor (3 of 9) ............................. 132
Figure 2-89 Remove the delivery fan, cartridge fan, and environmental sensor (4 of 9) ............................. 133
Figure 2-90 Remove the delivery fan, cartridge fan, and environmental sensor (5 of 9) ............................. 133
Figure 2-91 Remove the delivery fan, cartridge fan, and environmental sensor (6 of 9) ............................. 134
Figure 2-92 Remove the delivery fan, cartridge fan, and environmental sensor (7 of 9) ............................. 134
Figure 2-93 Remove the delivery fan, cartridge fan, and environmental sensor (8 of 9) ............................. 135
Figure 2-94 Remove the delivery fan, cartridge fan, and environmental sensor (9 of 9) ............................. 135
Figure 2-95 Remove the toner collection sensor (1 of 4) ......................................................................... 136
Figure 2-96 Remove the toner collection sensor (2 of 4) ......................................................................... 136
Figure 2-97 Remove the toner collection sensor (3 of 4) ......................................................................... 137
Figure 2-98 Remove the toner collection sensor (4 of 4) ......................................................................... 137
Figure 2-99 Remove the residual toner feed motor (1 of 7) ..................................................................... 138
Figure 2-100 Remove the residual toner feed motor (2 of 7) ................................................................... 139
Figure 2-101 Remove the residual toner feed motor (3 of 7) ................................................................... 139
Figure 2-102 Remove the residual toner feed motor (4 of 7) ................................................................... 140
Figure 2-103 Remove the residual toner feed motor (5 of 7) ................................................................... 140
7
xxviii ENWW
Figure 2-104 Remove the residual toner feed motor (6 of 7) ................................................................... 141
Figure 2-105 Remove the residual toner feed motor (7 of 7) ................................................................... 141
Figure 2-106 Reinstall the residual toner collection door ........................................................................ 142
Figure 2-107 Remove the RD sensor assembly (1 of 6) .......................................................................... 143
Figure 2-108 Remove the RD sensor assembly (2 of 6) .......................................................................... 144
Figure 2-109 Remove the RD sensor assembly (3 of 6) .......................................................................... 144
Figure 2-110 Remove the RD sensor assembly (4 of 6) .......................................................................... 145
Figure 2-111 Remove the RD sensor assembly (5 of 6) .......................................................................... 145
Figure 2-112 Remove the RD sensor assembly (6 of 6) .......................................................................... 146
Figure 2-113 Remove the power supply fan (1 of 4) .............................................................................. 147
Figure 2-114 Remove the power supply fan (2 of 4) .............................................................................. 148
Figure 2-115 Remove the power supply fan (3 of 4) .............................................................................. 148
Figure 2-116 Remove the power supply fan (4 of 4) .............................................................................. 149
Figure 2-117 Remove the registration assembly (1 of 8) ........................................................................ 150
Figure 2-118 Remove the registration assembly (2 of 8) ........................................................................ 151
Figure 2-119 Remove the registration assembly (3 of 8) ........................................................................ 151
Figure 2-120 Remove the registration assembly (4 of 8) ........................................................................ 152
Figure 2-121 Remove the registration assembly (5 of 8) ........................................................................ 152
Figure 2-122 Remove the registration assembly (6 of 8) ........................................................................ 153
Figure 2-123 Remove the registration assembly (7 of 8) ........................................................................ 153
Figure 2-124 Remove the r
Figure 2-125 Remove the ICB (1 of 3) ................................................................................................. 158
Figure 2-126 Remove the ICB (2 of 3) ................................................................................................. 159
Figure 2-127 Remove the ICB (3 of 3) ................................................................................................. 159
Figure 2-128 Remove the DC controller PCA and tray (1 of 4) ............................................................... 160
Figure 2-129 Remove the DC controller PCA and tray (2 of 4) ............................................................... 161
Figure 2-130 Remove the DC controller PCA and tray (3 of 4) ............................................................... 161
Figure 2-131 Remove the DC controller PCA and tray (4 of 4) ............................................................... 162
Figure 2-132 Remove the low voltage power supply (1 of 7) .................................................................. 163
Figure 2-133 Remove the low voltage power supply (2 of 7) .................................................................. 164
Figure 2-134 Remove the low voltage power supply (3 of 7) .................................................................. 164
Figure 2-135 Remove the low voltage power supply (4 of 7) .................................................................. 165
Figure 2-136 Remove the low voltage power supply (5 of 7) .................................................................. 165
Figure 2-137 Remove the low voltage power supply (6 of 7) .................................................................. 166
Figure 2-138 Remove the low voltage power supply (7 of 7) .................................................................. 166
Figure 2-139 Remove the high voltage power supply lower (1 of 4) ........................................................ 167
Figure 2-140 Remove the high voltage power supply lower (2 of 4) ........................................................ 168
Figure 2-141 Remove the high voltage power supply lower (3 of 4) ........................................................ 168
Figure 2-142 Remove the high voltage power supply lower (4 of 4) ........................................................ 169
Figure 2-143 Reinstall the high voltage power supply lower ................................................................... 169
Figure 2-144 Remove the d
egistration assembly (8 of 8) ........................................................................ 154
eveloping disengagement motor (1 of 2) ....................................................... 170
ENWW xxix
Figure 2-145 Remove the developing disengagement motor (2 of 2) ....................................................... 171
Figure 2-146 Remove the pickup motor ............................................................................................... 172
Figure 2-147 Remove the lifter drive assembly (1 of 2) .......................................................................... 173
Figure 2-148 Remove the lifter drive assembly (2 of 2) .......................................................................... 174
Figure 2-149 Remove the automatic close assembly .............................................................................. 175
Figure 2-150 Remove the cassette pickup drive assembly (1 of 10) ......................................................... 176
Figure 2-151 Remove the cassette pickup drive assembly (2 of 10) ......................................................... 177
Figure 2-152 Remove the cassette pickup drive assembly (3 of 10) ......................................................... 177
Figure 2-153 Remove the cassette pickup drive assembly (4 of 10) ......................................................... 178
Figure 2-154 Remove the cassette pickup drive assembly (5 of 10) ......................................................... 178
Figure 2-155 Remove the cassette pickup drive assembly (6 of 10) ......................................................... 179
Figure 2-156 Remove the cassette pickup drive assembly (7 of 10) ......................................................... 179
Figure 2-157 Remove the cassette pickup drive assembly (8 of 10) ......................................................... 180
Figure 2-158 Remove the cassette pickup drive assembly (9 of 10) ......................................................... 180
Figure 2-159 Remove the cassette pickup drive assembly (10 of 10) ....................................................... 181
Figure 2-160 Reinstall the cassette pickup drive assembly (1 of 3) .......................................................... 181
Figure 2-161 Reinstall the cassette pickup drive assembly (2 of 3) .......................................................... 182
Figure 2-162 Reinstall the cassette pickup drive assembly (3 of 3) .......................................................... 182
Figure 2-163 Remove the cassette pickup assembly (1 of 3) ................................................................... 184
Figure 2-164 Remove the cassette pickup assembly (2 of 3) ................................................................... 184
Figure 2-165 Remove the cassette pickup assembly (3 of 3) ................................................................... 185
Figure 2-166 Remove the l
Figure 2-167 Remove the laser/scanner assembly (Y/M) (2 of 12) ......................................................... 187
Figure 2-168 Remove the laser/scanner assembly (Y/M) (3 of 12) ......................................................... 187
Figure 2-169 Remove the laser/scanner assembly (Y/M) (4 of 12) ......................................................... 188
Figure 2-170 Remove the laser/scanner assembly (Y/M) (5 of 12) ......................................................... 188
Figure 2-171 Remove the laser/scanner assembly (Y/M) (6 of 12) ......................................................... 189
Figure 2-172 Remove the laser/scanner assembly (Y/M) (7 of 12) ......................................................... 189
Figure 2-173 Remove the laser/scanner assembly (Y/M) (8 of 12) ......................................................... 190
Figure 2-174 Remove the laser/scanner assembly (Y/M) (9 of 12) ......................................................... 190
Figure 2-175 Remove the laser/scanner assembly (Y/M) (10 of 12) ....................................................... 191
Figure 2-176 Remove the laser/scanner assembly (Y/M) (11 of 12) ....................................................... 191
Figure 2-177 Remove the laser/scanner assembly (Y/M) (12 of 12) ....................................................... 192
Figure 2-178 Remove the laser/scanner assembly (C/Bk) (1 of 7) .......................................................... 194
Figure 2-179 Remove the laser/scanner assembly (C/Bk) (2 of 7) .......................................................... 194
Figure 2-180 Remove the laser/scanner assembly (C/Bk) (3 of 7) .......................................................... 195
Figure 2-181 Remove the laser/scanner assembly (C/Bk) (4 of 7) .......................................................... 195
Figure 2-182 Remove the laser/scanner assembly (C/Bk) (5 of 7) .......................................................... 196
Figure 2-183 Remove the laser/scanner assembly (C/Bk) (6 of 7) .......................................................... 197
Figure 2-184 Remove the laser/scanner assembly (C/Bk) (7 of 7) .......................................................... 198
Figure 2-185 Reinstall the PGC actuators (1 of 5) ................................................................................. 198
aser/scanner assembly (Y/M) (1 of 12) ......................................................... 186
xxx ENWW
Figure 2-186 Reinstall the PGC actuators (2 of 5) ................................................................................. 199
Figure 2-187 Reinstall the PGC actuators (3 of 5) ................................................................................. 199
Figure 2-188 Reinstall the PGC actuators (4 of 5) ................................................................................. 200
Figure 2-189 Reinstall the PGC actuators (5 of 5) ................................................................................. 200
Figure 2-190 Remove the high voltage power supply upper (1 of 5) ....................................................... 202
Figure 2-191 Remove the high voltage power supply upper (2 of 5) ....................................................... 202
Figure 2-192 Remove the high voltage power supply upper (3 of 5) ....................................................... 203
Figure 2-193 Remove the high voltage power supply upper (4 of 5) ....................................................... 203
Figure 2-194 Remove the high voltage power supply upper (5 of 5) ....................................................... 204
Figure 2-195 Reinstall the high voltage power supply upper ................................................................... 205
Figure 2-196 Remove the drum motor 1 ............................................................................................... 207
Figure 2-197 Remove the drum motor 2 or drum motor 3 ...................................................................... 209
Figure 2-198 Remove the fuser motor .................................................................................................. 211
Figure 2-199 Remove the main drive assembly (1 of 7) ......................................................................... 213
Figure 2-200 Remove the main drive assembly (2 of 7) ......................................................................... 213
Figure 2-201 Remove the main drive assembly (3 of 7) ......................................................................... 214
Figure 2-202 Remove the main drive assembly (4 of 7) ......................................................................... 214
Figure 2-203 Remove the main drive assembly (5 of 7) ......................................................................... 215
Figure 2-204 Remove the mai
Figure 2-205 Remove the main drive assembly (7 of 7) ......................................................................... 216
Figure 2-206 Reinstall the main drive assembly (1 of 11) ....................................................................... 217
Figure 2-207 Reinstall the main drive assembly (2 of 11) ....................................................................... 217
Figure 2-208 Reinstall the main drive assembly (3 of 11) ....................................................................... 218
Figure 2-209 Reinstall the main drive assembly (4 of 11) ....................................................................... 218
Figure 2-210 Reinstall the main drive assembly (5 of 11) ....................................................................... 219
Figure 2-211 Reinstall the main drive assembly (6 of 11) ....................................................................... 220
Figure 2-212 Reinstall the main drive assembly (7 of 11) ....................................................................... 220
Figure 2-213 Reinstall the main drive assembly (8 of 11) ....................................................................... 221
Figure 2-214 Reinstall the main drive assembly (9 of 11) ....................................................................... 221
Figure 2-215 Reinstall the main drive assembly (10 of 11) ..................................................................... 222
Figure 2-216 Reinstall the main drive assembly (11 of 11) ..................................................................... 222
Figure 2-217 Remove the fuser drive assembly (1 of 6) .......................................................................... 224
Figure 2-218 Remove the fuser drive assembly (2 of 6) .......................................................................... 224
Figure 2-219 Remove the fuser drive assembly (3 of 6) .......................................................................... 225
Figure 2-220 Remove the fuser drive assembly (4 of 6) .......................................................................... 225
Figure 2-221 Remove the fuser drive assembly (5 of 6) .......................................................................... 226
Figure 2-222 Remove the fuser drive assembly (6 of 6) .......................................................................... 226
Figure 2-223 Reinstall the fuser drive assembly ..................................................................................... 227
Figure 2-224 Remove the delivery assembly (1 of 5) ............................................................................. 2
Figure 2-225 Remove the delivery assembly (2 of 5) ............................................................................. 229
Figure 2-226 Remove the delivery assembly (3 of 5) ............................................................................. 230
n drive assembly (6 of 7) ......................................................................... 215
29
ENWW xxxi
Figure 2-227 Remove the delivery assembly (4 of 5) ............................................................................. 230
Figure 2-228 Remove the delivery assembly (5 of 5) ............................................................................. 231
Figure 2-229 Reinstall the delivery assembly (1 of 2) ............................................................................. 232
Figure 2-230 Reinstall the delivery assembly (2 of 2) ............................................................................. 232
Figure 2-231 Remove the duplex drive assembly (1 of 2) ....................................................................... 234
Figure 2-232 Remove the duplex drive assembly (2 of 2) ....................................................................... 234
Figure 2-233 Remove the drawer connector; optional paper feeder ........................................................ 236
Figure 3-1 Diagnostic test (1 of 3) ....................................................................................................... 255
Figure 3-2 Diagnostic test (2 of 3) ....................................................................................................... 255
Figure 3-3 Diagnostic test (3 of 3) ....................................................................................................... 256
Figure 3-4 Engine-test button .............................................................................................................. 257
Figure 3-5 Test the registration sensor .................................................................................................. 261
Figure 3-6 Test the fuser loop sensors .................................................................................................. 262
Figure 3-7 Test the fuser output sensor (1 of 2) ...................................................................................... 263
Figure 3-8 Test the fuser output sensor (2 of 2) ...................................................................................... 263
Figure 3-9 Test the duplexer refeed sensor ........................................................................................... 264
Figure 3-10 Test the output-bin-full sensor ............................................................................................. 265
Figure 3-11 Test the fuser pressure-release sensor (1 of 2) ...................................................................... 266
Figure 3-12 Test the fuser pressure-release sensor (2 of 2) ...................................................................... 266
Figure 3-13 Test the ITB alienation sensor (1 of 2) ................................................................................. 267
Figure 3-14 Test the ITB alienation sensor (2 of 2) ................................................................................. 268
Figure 3-15 Test the ri
Figure 3-16 Test the right- and front-door interlock switches (2 of 4) ........................................................ 269
Figure 3-17 Test the right- and front-door interlock switches (3 of 4) ........................................................ 270
Figure 3-18 Test the right- and front-door interlock switches (4 of 4) ........................................................ 270
Figure 3-19 Test the Tray 1 paper sensor ............................................................................................. 272
Figure 3-20 Test the Tray 2 paper sensor ............................................................................................. 273
Figure 3-21 Test the Tray 2 cassette sensor (1 of 2) ............................................................................... 274
Figure 3-22 Test the Tray 2 cassette sensor (2 of 2) ............................................................................... 274
Figure 3-23 Test the Tray 2 cassette lifter sensor ................................................................................... 275
Figure 3-24 Test the optional Tray 3 empty sensor ................................................................................ 276
Figure 3-25 Test the optional Tray 3 media feed sensor ......................................................................... 277
Figure 3-26 Test the optional Tray 3 stack surface sensor ....................................................................... 278
Figure 3-27 Test the optional Tray 3 media size sensors ........................................................................ 279
Figure 3-28 Sensors .......................................................................................................................... 282
Figure 3-29 DC controller PCA ........................................................................................................... 284
Figure 3-30 Paper feeder driver PCA ................................................................................................. 285
Figure 3-31 Component locations (1 of 6) ............................................................................................ 286
Figure 3-32 Component locations (2 of 6) ...........................................................................
Figure 3-33 Component locations (3 of 6) ............................................................................................ 288
Figure 3-34 Component locations (4 of 6) ............................................................................................ 289
ght- and front-door interlock switches (1 of 4) ........................................................ 269
................. 287
xxxii ENWW
Figure 3-35 Component locations (5 of 6) ............................................................................................ 290
Figure 3-36 Component locations (6 of 6) ............................................................................................ 291
Figure 3-37 1 x 500 paper feeder ...................................................................................................... 293
Figure 3-38 General timing chart ........................................................................................................ 294
Figure 3-39 General circuit diagram ................................................................................................... 295
Figure 3-40 Paper feeder circuit diagram ............................................................................................ 296
Figure 3-41 Print-quality troubleshooting procedure ............................................................................... 297
Figure 3-42 Yellow print-quality troubleshooting page ........................................................................... 298
Figure 3-43 Yellow comparison page .................................................................................................. 298
Figure 3-44 Black print-quality troubleshooting page ............................................................................. 299
Figure 3-45 Configuration page ......................................................................................................... 304
Figure 3-46 HP embedded Jetdirect page ............................................................................................ 305
Figure 3-47 Repetitive defects ruler ..................................................................................................... 308
Figure 3-48 Sample event log ............................................................................................................ 468
Figure 3-49 Jam locations .................................................................................................................. 472
Figure 4-1 External covers, panels, and doors ...................................................................................... 532
Figure 4-2 Right-door assembly ........................................................................................................... 534
Figure 4-3 Internal assemblies (1 of 5) ................................................................................................. 536
Figure 4-4 Internal assemblies (2 of 5) ................................................................................................. 538
Figure 4-5 Internal assemblies (3 of 5) ................................................................................................. 540
Figure 4-6 Internal assemblies (4 of 5) ................................................................................................. 542
Figure 4-7 Internal assemblies (5 of 5) ................................................................................................. 544
Figure 4-8 Cassette ........................................................................................................................... 546
Figure 4-9 Paper
Figure 4-10 PCAs ............................................................................................................................. 550
Figure 4-11 1 x 500-sheet paper feeder .............................................................................................. 552
Figure 4-12 Paper feeder covers ......................................................................................................... 554
Figure 4-13 Paper feeder main body ................................................................................................... 556
Figure 4-14 Cassette ......................................................................................................................... 558
Figure 4-15 Paper feeder PCA ........................................................................................................... 560
pickup assembly ...................................................................................................... 548
ENWW xxxiii
xxxiv ENWW
1 Theory of operation
Basic operation
●
Engine control system
●
Laser/scanner system
●
Image formation system
●
Pickup, feed, and delivery system
●
Jam detection
●
Optional paper feeder
●
ENWW 1
Basic operation
The product routes all high-level processes through the formatter, which stores font information,
processes the print image, and 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
Engine control system
Image-formation system
Media-feed system
Option
2 Chapter 1 Theory of operation ENWW
Sequence of operation
The DC controller PCA controls the operating sequence, as described in the following table.
NOTE: The terms fusing and fixing are synonymous.
Table 1-1 Sequence of operation
Period Duration Description
Waiting From the time the power is turned on,
the door is closed, or when the product
exits Sleep mode until the product is
ready for printing
Standby From the end of the waiting sequence or
the last rotation until the formatter
receives a print command or until the
product is turned off
Initial rotation From the time the formatter receives a
print command until the paper enters the
paper path
Printing From the time the first sheet of paper
enters the paper path until the last sheet
has passed through the fuser
Heats the fuser sleeve
●
Pressurizes the fuser pressure roller
●
Detects the print cartridges
●
Detects the home position for the
●
primary transfer roller and the
developing unit
Cleans the secondary transfer roller
●
The product is in the READY state.
●
The product enters Sleep mode
●
after the specified length of time.
The product calibrates if it is time
●
for an automatic calibration.
Activates the high-voltage power
●
supply
Prepares each laser/scanner unit
●
Warms the fuser to the correct
●
temperature
Forms the image on the
●
photosensitive drums
Transfers the toner to the paper
●
ENWW
Last rotation From the time the last sheet of paper
exits the fuser until the motors stop
rotating
Fuses the toner image onto the
●
paper
Performs calibration after a
●
specified number of pages
Moves the last printed sheet into
●
the output bin
Stops each laser/scanner unit
●
Discharges the bias from the high-
●
voltage power supply
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
●
High-voltage power supply
●
Low-voltage power supply
●
Figure 1-2 Engine control system
Laser/scanner system
Image-formation system
Media-feed system
Option
4 Chapter 1 Theory of operation ENWW
DC controller
The DC controller controls the operational sequence of the printer.
Figure 1-3 DC controller block diagram
Fuser
Laser/scanner
ENWW
Engine control system
5
Solenoids
Table 1-2 Solenoids
Component abbreviation Component name
SL1 Primary transfer roller disengagement solenoid
SL2 Duplex reverse solenoid (HP LaserJet Enterprise 500 color M551dn and HP LaserJet Enterprise
SL3 Multipurpose-tray pickup solenoid
SL4 Cassette pickup solenoid
Clutches
Table 1-3 Clutches
Component abbreviation Component name
CL1 Duplex re-pickup clutch (HP LaserJet Enterprise 500 color M551dn and HP LaserJet Enterprise
500 color M551xh only)
500 color M551xh only)
Switches
Table 1-4 Switches
Component abbreviation Component name
SW1, SW2 5V interlock switch
SW3 24V interlock switch
SW4 Power switch
Test print switch
6 Chapter 1 Theory of operation ENWW
Sensors
Table 1-5 Sensors
Component abbreviation Component name
SR1 Drum home position sensor 1
SR2 Drum home position sensor 2
SR3 Drum home position sensor 3
SR5 Fuser output sensor
SR6 Output bin full sensor
SR7 Fuser pressure release sensor
SR8 Registration sensor
SR9 Fuser pressure release sensor
SR11 Developer alienation sensor
SR13 Tray 2 cassette sensor
SR14 Fuser loop 1 sensor
SR15 Fuser loop 2 sensor
SR17 ITB alienation sensor
SR20 Tray 2 paper sensor
SR21 Tray 1 paper sensor
SR22 Duplexer refeed sensor (HP LaserJet Enterprise 500 color M551dn and HP LaserJet Enterprise
500 color M551xh only)
OHT sensor (in)
OHT sensor (out)
RD sensor (front)
RD sensor (rear)
Environmental sensor (temperature and humidity)
Yellow toner-level sensor
Magenta toner-level sensor
Cyan toner-level sensor
Black toner-level sensor
Toner collection-box-full sensor
Motors and fans
ENWW
Engine control system
7
The product has 11 motors and three fan motors. The motors drive the components in the paper-feed
and image-formation systems. The fan motors cool the product's inside.
Table 1-6 Motors
Abbreviation Name Purpose Type Failure detection
M2 Fuser motor Drives the Fuser roller,
the delivery roller, and
the Fuser pressure
roller
M3 Drum motor 1 Drives the
photosensitive drum
(yellow/magenta),
developing unit
(yellow), and primary
charging roller
(yellow/magenta)
M4 Drum motor 2 Drives the
photosensitive drum
(cyan), developing unit
(magenta/cyan), and
primary charging roller
(cyan)
M5 Drum motor 3 Drives the
photosensitive drum
(black), developing unit
(black), and ITB drive
roller, and secondary
transfer roller
M7 Lifter motor Drives the lifter for the
cassette
DC motor Yes
DC motor Yes
DC motor Yes
DC motor Yes
Stepping motor Yes
M8 Cyan/black scanner
motor
M9 Yellow/magenta
scanner motor
M10 Developing
disengagement motor
M11 Duplex reverse motor
(HP LaserJet Enterprise
500 color M551dn
and HP LaserJet
Enterprise 500 color
M551xh only)
Drives the scanner
mirror in the cyan/
black laser scanner
Drives the scanner
mirror in the yellow/
magenta laser scanner
Drives the developing
unit disengagement
Drives the duplex
reverse roller and
duplex feed roller
DC motor Yes
DC motor Yes
Stepping motor No
Stepping motor No
8 Chapter 1 Theory of operation ENWW
Table 1-6 Motors (continued)
Abbreviation Name Purpose Type Failure detection
M12 Residual toner-feed
motor
M13 Pickup motor Drives the cassette
Drives the residual
toner feed screw
pickup roller, MP tray
pickup roller, feed
roller, registration
roller, and re-pickup
roller
DC motor Yes
Stepping motor No
Table 1-7 Fans
Abbreviation Name Cooling area Type Speed
FM1 Power supply fan Around the power
supply unit
FM2 Cartridge fan Around the cartridges Intake Full/half
FM3 Delivery fan Around the delivery
unit
Intake Full/half
Intake Full/half
ENWW
Engine control system
9
High voltage power supply
The high-voltage power supply delivers the high-voltage biases to the following components used to
transfer toner during the image-formation process:
Primary-charging roller (in the cartridge)
●
Developing roller (in the cartridge)
●
Primary-transfer roller
●
Secondary-transfer roller
●
Figure 1-4 High voltage power supply circuits
Y
M
C
K
The high voltage power supply contains several separate circuits.
Table 1-8 High voltage power supply circuits
Circuit Description
Primary-charging-bias generation DC negative bias is applied to the surface of the photosensitive drum to prepare it
for image formation.
Developing-bias generation DC negative bias adheres the toner to each photosensitive drum during the image-
formation process.
10 Chapter 1 Theory of operation ENWW
Table 1-8 High voltage power supply circuits (continued)
Circuit Description
Primary-transfer-bias generation DC positive bias transfers the latent toner image from each photosensitive drum
onto the ITB.
Secondary-transfer-bias generation Two DC biases, one positive and one negative, transfer the toner from the ITB onto
the paper.
ENWW
Engine control system
11
Low voltage power supply
The low-voltage power-supply circuit converts the AC power from the wall receptacle into the DC
voltage that the product components use. The product has two low-voltage power-supplies for 110 Volt
or 220 Volt input.
Figure 1-5 Low voltage power-supply circuit
AC input
Fuse
Noise filter
DC controller
Fuse
Noise filter
Zero crossing
Switch
Rectifying
circuit
+5V
generation
circuit
Low-voltage power supply
circuit
Rectifying
circuit
Protection circuit
Switch
Fixing control
circuit
+24V
generation
circuit
Protection circuit
+3.3V
generation
circuit
+5VB
ICB
PSTYP100
/ZEROX
24VRMT
+24VB
+24VA
SW3
+24VB
+5VA
PWRSAVE
+3.3VA
VC5VOFF
VC3VOFF
Switch
Switch
+3.3VC
Switch
+3.3VB
+3.3VA
+5VB
+5VD
Power switch
PWRSWON
SW1
+5VC
SW2
Formatter
The low voltage power supply converts the AC power into three DC voltages, which it then subdivides,
as described in the following table.
12 Chapter 1 Theory of operation ENWW
Table 1-9 Converted DC voltages
Main DC voltage Sub-voltage Behavior Notes
+24 V +24VA Stopped during Sleep
(powersave) mode
+24VB Interrupted when the front
door or right door open
Stopped during Sleep
(powersave) mode
+5 V +5VA Supplied during Sleep
(powersave) mode 2 and
Sleep (powersave) mode 3
+5VB Supplied during Sleep
(powersave) mode 2
Stopped during Sleep
(powersave) mode 3
Supplies power to the
formatter
+5VC Supplied during Sleep
(powersave) mode 2 and
Sleep (powersave) mode 3
Interrupted when the front
door or right door open
The 24V POWER SUPPLY
(24VRMT) signal controls
supply or interruption of
+24VA.
The VOLTAGE
CONVERSION (PWRSAVE)
signal converts output voltage
of +5VA into 3.2V.
The 5V POWER SUPPLY
(VC5VOFF) signal sontrols
supply or interruption of
+5VB.
The VOLTAGE
CONVERSION (PWRSAVE)
signal converts output voltage
of +5VB into 3.2V
the VOLTAGE CONVERSION
(PWRSAVE) signal converts
output voltage of +5VC into
3.2V.
ENWW
+5VD Stopped during Sleep
(powersave) mode
Interrupted when the front
door or right door open
+3.3 V 3.3VA Constantly supplied
3.3VB Stopped only when the power
is off
Supplies power to the
formatter
3.3VC Stopped during Sleep
(powersave) mode 2 and
Sleep (powersave) mode 3
Engine control system
The 3V POWER SUPPLY
(VC3VOFF) signal controls
supply or interruption of
+3.3VB.
13
Overcurrent/overvoltage protection
The low-voltage power supply stops supplying the DC voltage to the product components whenever it
detects excessive current or abnormal voltage from the power source.
The low-voltage power supply has a protective circuit against overcurrent and overvoltage to prevent
failures in the power supply circuit.
If the low-voltage power supply is not supplying DC voltage, the protective function might be running. In
this case, turn the power off and unplug the power cord. Do not plug in and turn on the product until
the cause is found and corrected.
In addition, the low-voltage power supply has two fuses (FU100/FU101) to protect against overcurrent.
If overcurrent flows into the AC line, the fuse blows to stop AC power.
Safety
For safety, the product interrupts the power supply of +24VB by turning off the interlock switch (SW3)
and +5VC by turning off the interlock switch (SW1/SW2).
The AC power is supplied to the product even when the power switch is turned off because the product
uses the soft switch for turning on/off the product. Always unplug the power cord before disassembling
the product.
Sleep (powersave) mode
Sleep mode conserves energy by stopping the power to several components when the product is idle.
The product has three sleep modes depending on the power consumption. The DC controller supplies or
converts each power supply according to the sleep mode.
Sleep mode 1: Stops +24VA and +24VB
●
Sleep mode 2: Stops +24VA, +24VB and +5VD. Converts +5VA, +5VB and +5VC into +3.2V.
●
Sleep mode 3: Stops +24VA, +24VB, +5VB and +5VD. Converts +5VA and +5VC into +3.2V.
●
Power supply voltage detection
The product detects the power supply voltage that is connected to the product. The DC controller
monitors the POWER SUPPLY VOLTAGE (PSTYP100) signal and detects power supply voltage, whether
100 V or 200 V, to control the fusing operation.
Low voltage power supply failure
The DC controller determines a low-voltage power supply failure and notifies the formatter when the
low-voltage power supply does not supply +24 V.
14 Chapter 1 Theory of operation ENWW
Power off condition
The DC controller turns off the product with the 24V POWER SUPPLY (24VRMT) signal, 5V POWER
SUPPLY (VC5VOFF) signal, 3V POWER SUPPLY (VC3VOFF) signal, and VOLTAGE CONVERSION
(PWRSAVE) signal.
+5VA and +5VC, are converted into +3.2V, and +3.3VA and supplied during the power off condition.
Fuser control
The fuser-control circuit controls the fuser temperature. The product uses an on-demand fusing method.
Figure 1-6 Fuser components
Fuser control
FUSER HEATING
CONTROL signal
FUSER TEMPERATURE signal
circuit
Fuser heater
safety circuit
Fuser sleeve
Table 1-10 Fuser components
Type of component Abbreviation Name Function
Heaters H1 Fuser heater Heats the fuser sleeve.
Thermistors
(Contact type)
Thermoswitches
(Non-contact type)
TH1 Main thermistor Each thermistor detects the center
temperature of the fuser sleeve.
TH2
TH3
TP1 For the fuser heater Controls the fuser-roller main
Sub thermistor Each thermistor detects the side
temperature of the fuser heater.
heater
ENWW
Engine control system
15
Fuser temperature control circuit
The temperatures of the two rollers in the fuser fluctuate according to the stage of the printing process.
The DC controller sends commands to the fuser-control circuit to adjust temperatures.
Figure 1-7 Fuser temperature control circuit
Fuser
Fuser sleeve unit
Fuser heater
control circuit
Fuser heater safety
circuit
Fuser
Fuser heater safety circuit
Fuser control circuit
Fuser
16 Chapter 1 Theory of operation ENWW
Fuser over temperature protection
To protect the fuser from excessive temperatures, the product has four layers of protective functions. If
one function fails, the subsequent functions should detect the problem.
DC controller: When a thermistor or thermopile detects a temperature above a certain threshold,
●
the DC controller interrupts power to the specific heater. Following are the thresholds for each
component:
TH1: 230° C (446° F) or higher
◦
TH2: 285° C (545° F) or higher
◦
TH3: 285° C (545° F) or higher
◦
Fuser heater safety circuit: If the DC controller fails to interrupt the power to the heaters at the
●
prescribed temperatures, the fuser heater safety circuit deactivates the triac-drive circuit and
releases the relay, which causes the heaters to stop at slightly higher temperature thresholds.
TH2: 290° C (554° F) or higher
◦
TH3: 290° C (554° F) or higher
◦
Current detection protection circuit: If current flowing in each triac exceeds a specific value,
●
the current detection protection circuit deactivates the triac-drive circuit and releases the relay,
which interrupts the power supply to the heaters.
Thermoswitch: If the temperature in the heaters is abnormally high, and the temperature in the
●
thermoswitches exceeds a specified value, the contact to the thermoswitch breaks. Breaking this
contact deactivates the triac-drive circuit and releases the relay, which interrupts the power supply
to the heaters. Following are the thresholds for each thermoswitch:
TP1: 270° C (518° F) or higher
◦
NOTE: When the thermoswitches reach this temperature, the temperature on the fuser rollers is about
320° C (608° F).
ENWW
Engine control system
17
Fuser failure detection
When the DC controller detects any of the following conditions, it determines that the fuser has failed.
The DC controller then interrupts power to the fuser heaters and notifies the formatter.
Abnormally high temperatures: Temperatures are too high for any of the following
●
components, at any time:
TH1: 230° C (446° F) or higher
◦
TH2: 285° C (545° F) or higher
◦
TH3: 285° C (545° F) or higher
◦
Abnormally low temperatures: Temperatures are too low at any of the following
●
components after the product has initialized.
TH1: 120° C (248° F) or lower
◦
TP2 or TP3: 100° C (212° F) or lower
◦
Or, the temperature drops in either of the thermopiles (TP1 and TP2) by 30° C (86° F) or more
within a specified length of time.
Abnormal temperature rise: The DC controller determines an abnormal temperature rise if
●
the detected temperature of TH1 does not rise 2° C within a specified time period after the fuser
motor is turned on, or if the detected temperature of the thermistors does not rise to a specified
temperature for a specified time after the fuser motor is turned on.
Thermistor open: The DC controller determines a thermistor open if:
●
The detected temperature of TH1 is kept at 12° C (53° F) or lower for a specified time after
◦
the fuser motor is turned on.
The detected temperature of TH2 is kept at 4° C (39° F) or lower for a specified time.
◦
The detected temperature of TH3 is kept at 4° C (39° F) or lower for a specified time.
◦
Drive-circuit failure: The DC controller determines a drive-circuit failure:
●
If the detected power supply frequency is out of a specified range when the printer is turned
◦
on or during the standby period
If the current detection circuit detects an out of specified current value
◦
Fuser discrepancy: The DC controller determines a fuser type mismatch when it detects an
●
unexpected fuser unit presence signal. The product has two fusers for 110 V or 220 V input
power.
18 Chapter 1 Theory of operation ENWW
Laser/scanner system
The laser/scanner system forms the latent electrostatic image on the photosensitive drums according to
the VIDEO signals sent from the formatter. The product has two laser/scanners: one for yellow and
magenta and the other for cyan and black.
The formatter sends the DC controller instructions for the image of the page to be printed. The DC
controller signals the lasers to emit light, and the laser beams pass through lenses and onto the scanner
mirror, which rotates at a constant speed. The mirror reflects the beam onto the photosensitive drum in
the pattern necessary for the image, exposing the surface of the drum so it can receive toner.
Figure 1-8 Laser/scanner system
ENWW
Laser/scanner system
19
The DC controller determines that a laser/scanner has failed when any of the following conditions
occurs:
Laser failure: The detected laser intensity does not match a specified value when the product
●
initializes.
Beam-detect (BD) failure: The BD interval is outside a specified range during printing.
●
Scanner-motor failure: The scanner motor does not reach a specified rotation speed within a
●
certain time after it begins rotating.
20 Chapter 1 Theory of operation ENWW
Image formation system
The image-formation system creates the printed image on the paper. The system consists of the laser/
scanners, print cartridges, imaging drums, ITB, and fuser.
Figure 1-9 Image formation system
Y
M
Fuser
C
Laser/scanner
K
Laser/scanner
ENWW
Image formation system
21
Image formation process
The image-formation system consists of ten steps divided into six functional blocks.
Figure 1-10 Image formation process
Y
M
Fusing
Fuser
C
K
Table 1-11 Image formation process
Functional block Steps Description
Latent image formation 1. Pre-exposure
2. Primary charging
3. Laser-beam exposure
Development 4. Development Toner adheres to the electrostatic latent
Transfer 5. Primary transfer
6. Secondary transfer
7. Separation
Fusing 8. Fusing The toner fuses to the paper to make a
ITB cleaning 9. ITB cleaning Residual toner is removed from the ITB.
Drum cleaning 10. Drum cleaning Residual toner is removed from the
An invisible latent image forms on the
surface of the photosensitive drums.
image on the photosensitive drums.
The toner image transfers to the ITB and
subsequently to the paper.
permanent image.
photosensitive drums.
22 Chapter 1 Theory of operation ENWW
Step 1: Pre-exposure
Light from the pre-exposure LED strikes the surface of the photosensitive drum to remove any residual
electrical charges from the drum surface.
Figure 1-11 Pre-exposure
Step 2: Primary charging
The primary-charging roller contacts the photosensitive drum and charges the drum with negative
potential.
Figure 1-12 Primary charging
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Image formation system
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Step 3: Laser-beam exposure
The laser beam strikes the surface of the photosensitive drum in the areas where the image will form.
The negative charge neutralizes in those areas, which are then ready to accept toner.
Figure 1-13 Laser-beam exposure
Step 4: Development
Toner acquires a negative charge as the developing cylinder contacts the developing blade. Because
the negatively charged surface of the photosensitive drums have been neutralized where they have
been struck by the laser beam, the toner adheres to those areas on the drums. The latent image
becomes visible on the surface of each drum.
Figure 1-14 Development
24 Chapter 1 Theory of operation ENWW
Step 5: Primary transfer
The positively charged primary-transfer rollers contact the ITB, giving the ITB a positive charge. The ITB
attracts the negatively charged toner from the surface of each photosensitive drum, and the complete
toner image transfers onto the ITB, beginning with yellow, followed by magenta, cyan, and black.
Figure 1-15 Primary transfer
Step 6: Secondary transfer
The paper acquires a positive charge from the secondary-transfer roller, and so it attracts the negatively
charged toner from the surface of the ITB. The complete toner image transfers onto the paper.
Figure 1-16 Secondary transfer
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Image formation system
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Step 7: Separation
The stiffness of the paper causes it to separate from the ITB as the ITB bends. The static-charge
eliminator removes excess charge from the paper to ensure that the toner fuses correctly.
Figure 1-17 Separation
Step 8: Fusing
To create the permanent image, the paper passes through heated, pressurized rollers to melt the toner
onto the page.
Figure 1-18 Fusing
Fuser sleeve
Fuser heater
26 Chapter 1 Theory of operation ENWW
Step 9: ITB cleaning
The cleaning blade scrapes the residual toner off the surface of the ITB. The residual toner feed screw
deposits residual toner in the toner collection box.
Figure 1-19 ITB cleaning
Step 10: Drum cleaning
Inside the print cartridge, the cleaning blade removes residual toner from the surface of the drum to
prepare it for the next image. The waste toner falls into the hopper in the print cartridge.
Figure 1-20 Drum cleaning
Print cartridge
The product has four print cartridges, one for each color. Each print cartridge contains a reservoir of
toner and the following components:
Photosensitive drum
●
Developing roller
●
Primary-charging roller
●
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Image formation system
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The DC controller rotates the drum motor to drive the photosensitive drum, developing roller, and the
primary-charging roller.
Figure 1-21 Print-cartridge system
The DC controller rotates the drum motor to drive the photosensitive drum, developing unit, and primary
charging roller.
The memory tag is a non-volatile memory chip that stores information about the usage for the print
cartridge.
28 Chapter 1 Theory of operation ENWW
The DC controller notifies the formatter of an error if any of the following conditions exist:
The memory tag fails to either read to or write from the DC controller
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The RD sensors detect a missing or incorrectly installed print cartridge.
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The accumulated print time reaches a specified time period or the cartridge runs out of toner.
●
The toner level in any of the print cartridges drops below a certain level
●
Developing roller engagement and disengagement
The product can print in full-color mode or in black-only mode. To print in black-only mode, the product
disengages the developing rollers in the cyan, magenta, and yellow print cartridges. This maximizes
the life of the cartridges.
Figure 1-22 Developing-roller engagement and disengagement control
Four developing units engaged
Y
Y
M
M
C
C
K
K
Only the Bk developing unit engaged
Y
Y
M
Four developing units disengaged
Y
Y
M
M
C
C
K
K
M
C
C
K
K
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The DC controller rotates the developing disengagement motor and changes the direction of the cam
according to the instructions from the formatter for each print job.
When the product is turned on and at the end of each print job, all four of the developing rollers
disengage from the photosensitive drums. If the next print job is full-color mode, each of the developing
rollers engage. If the next print job is black-only mode, only the black developing roller engages.
If the DC controller does not detect any output from the developing home-position sensor, it determines
that the developing-disengagement motor has failed.
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Intermediate transfer belt (ITB) unit
The ITB unit accepts the toner images from the photosensitive drums and transfers the completed image
to the paper. The ITB unit has these main components:
ITB
●
ITB drive roller
●
ITB-driven roller
●
Primary-transfer rollers
●
ITB cleaner
●
The ITB motor drives the ITB drive roller, which rotates the ITB. The motion of the ITB causes the primary
transfer rollers to rotate. The ITB cleaner cleans the ITB surface.
Figure 1-23 ITB unit
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Primary-transfer-roller engagement and disengagement
Depending on the requirements of the print job, the primary-transfer rollers engage with the ITB so it
can receive toner from the photosensitive drums.
Table 1-12 Primary-transfer-roller engagement states
Roller state Product state
All rollers disengaged The home position for the ITB unit
32 Chapter 1 Theory of operation ENWW
Table 1-12 Primary-transfer-roller engagement states (continued)
Roller state Product state
All rollers engaged The state for a full-color print job
Black roller engaged The state for a black-only print job
Figure 1-24 Three states of primary-transfer-roller engagement and disengagement
Fuser motor
Four colors are disengaged
Y
FUSER MOTOR CONTROL
Y
Four colors are engaged
Y
Y
Only black is engaged
Y
Y
M
M
M
M
C
C
K
K
M
C
C
K
K
M
C
C
K
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K
The primary-transfer-roller disengagement motor rotates or reverses to place the primary-transfer-roller
disengagement cam into one of three positions. The cam causes the transfer-roller slide plate to move to
the right or left. This movement causes the primary-transfer rollers to move up to engage the ITB with the
photosensitive drum or down to disengage it.
Image formation system
33
If the DC controller does not receive the expected signal from the ITB home-position sensor when the
primary-transfer-roller engages or disengages, but the primary-transfer-roller disengagement motor is
rotating, the DC controller determines that the primary-transfer-disengagement mechanism has failed,
and notifies the formatter.
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ITB cleaning
The cleaning blade in the ITB cleaner scrapes the residual toner off the ITB surface. The drum motor
(M5) drives the residual toner feed screw. The screw feeds the residual toner to the residual toner feed
unit. The residual toner feed motor (M12) drives the residual toner feed screw. The residual toner feed
screw deposits the residual toner in the toner collection box. The DC control detects whether the toner
collection box is full, using the toner collection-box-full sensor, and then notifies the formatter.
Figure 1-25 ITB cleaning process
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Calibration
The product calibrates itself to maintain excellent print quality. Calibration corrects color-misregistration
and color-density variation.
During calibration, the product places a specific pattern of toner on the surface of the ITB. Sensors at
the end of the ITB read the toner pattern to determine if adjustments are necessary.
Figure 1-26 Toner patterns for calibration
Color misregistration control
Internal variations in the laser/scanners can cause the toner images to become misaligned. The colormisregistration control corrects the following problems:
Horizontal scanning start position
●
Horizontal scanning magnification
●
Vertical scanning start position
●
The calibration occurs when any of the following occurs:
A cartridge is replaced
●
The temperature of the sub thermistor is 50 C (122 F) or lower when the product recovers from
●
sleep mode after a specific number of pages print.
A specified number of pages have printed.
●
The formatter sends a command.
●
The user requests a calibration by using the control-panel menus.
●
36 Chapter 1 Theory of operation ENWW
If data from the color-misregistration and image-density sensors is outside a specified range when the
product is turned on or when it is beginning the calibration sequence, the DC controller determines that
these sensors have failed, and it notifies the formatter.
Image stabilization control
Environmental changes or deterioration of the photosensitive drums and toner can cause variations in
the image density. The image-stabilization control reduces these fluctuations. There are three kinds of
image stabilization controls.
Table 1-13 Image-stabilization controls
Image stabilization control Description
Environment change control The environment change control calibrates each high-voltage bias to obtain an
Image density control (DMAX) This control corrects variations in image density related to deterioration of the
appropriate image according to the environment changes. The DC controller
determines the environment where the product is installed based on the surrounding
temperature and humidity data from the environment sensor, controls, and related
biases. This control occurs under the following circumstances:
The print cartridge is replaced.
●
The DC controller notifies the formatter when it encounters a communication error
with the environmental sensor.
photosensitive drum or the toner. The DC controller adjusts the high-voltage biases
to correct the problem under the following conditions:
The sub thermistor detects a temperature that is too low when the product is
●
turned on.
After a specific period of the completion of a print operation
●
A print cartridge is replaced.
●
The ITB is replaced.
●
A specified number of pages have printed.
●
The formatter sends a command.
●
The environment is relatively charged.
●
Image halftone control (DHALF) The DC controller measures the halftone pattern according to the command from the
formatter. The formatter performs this control to calibrate the halftone, based on the
halftone-density measurements, under the following conditions:
The formatter sends a command.
●
DMAX is completed.
●
The DC controller determines a RD sensor failure and notifies the formatter if it detects an out-ofspecified-data value from the RD sensor when the product is turned on or when the color misregistration
control starts.
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Pickup, feed, and delivery system
The pickup, feed, and delivery system uses a series of rollers to move the paper through the product.
Figure 1-27 Switches and sensors for the pickup, feed, and delivery system (1 of 2)
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Table 1-14 Switches and sensors for the pickup, feed, and delivery system (1 of 2)
Abbreviation Component
SR5 Fuser output
SR6 Output bin full
SR7 Fuser pressure release
SR8 Registration
SR9 Tray 2 cassette lifter
SR13 Tray 2 cassette sensor
SR14 Fuser loop 1
SR15 Fuser loop 2
SR20 Tray 2 paper
38 Chapter 1 Theory of operation ENWW
Table 1-14 Switches and sensors for the pickup, feed, and delivery system (1 of 2) (continued)
Abbreviation Component
SR21 Tray 1 paper
SR22 Duplexer refeed (duplex models only)
Figure 1-28 Switches and sensors for the pickup, feed, and delivery system (2 of 2)
SR10
Table 1-15 Switches and sensors for the pickup, feed, and delivery system (2 of 2)
Abbreviation Component
SR10 Paper Width (Tray 2)
NOTE: For more information about this sensor, see
Cassette media width detection on page 47.
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Figure 1-29 Motors and solenoids for the pickup, feed, and delivery system
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Table 1-16 Motors and solenoids for the pickup, feed, and delivery system
Abbreviation Component
M2 Fuser motor
M5 Drum motor 3
M7 Lifter motor
M11 Duplex reverse motor (duplex models only)
M13 Pickup motor
CL1 Duplex re-pickup clutch (duplex models only)
SL2 Duplex reverse solenoid (duplex models only)
SL3 Multipurpose tray pickup solenoid
SL4 Cassette pickup solenoid
40 Chapter 1 Theory of operation ENWW
Figure 1-30 Three main units of the pickup, feed, and delivery system
Fuser/delivery block
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Duplex block
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Pickup-and-feed unit
The pickup-and-feed unit picks an individual sheet of paper from the multipurpose tray or the cassettes,
carries it through the secondary-transfer unit, and feeds it into the fuser.
Figure 1-31 Pick feed mechanism
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Cassette pickup
The sequence of steps for the cassette-tray pickup operation is the following:
1. When the product starts or the tray closes, the lifting mechanism lifts the paper stack so it is ready.
2. After receiving a print command from the formatter, the DC controller rotates the pickup motor,
which causes the cassette pickup roller, cassette feed roller, and cassette separation roller to
rotate.
3. The DC controller drives the cassette pickup solenoid, which rotates the cassette pickup cam. As
the pickup cam rotates, the pickup arm moves down, and the cassette pickup roller touches the
surface of the paper stack. The cassette pickup roller then picks up one sheet of paper.
Figure 1-32 Cassette-pickup mechanism
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NOTE: The lift-up operation lifts the lifting plate to keep the stack surface of the media at a pickup
position. The lifting spring helps support the lifting plate depending on the media size and amount.
Pickup, feed, and delivery system
43
Cassette presence detection
The cassette presence sensor is in the lifter drive unit. The sensor detects the cassette-presence sensor
flag and determines whether the cassette is installed correctly.
Figure 1-33 Cassette presence sensor
44 Chapter 1 Theory of operation ENWW
Cassette lift operation
The DC controller rotates the lifter motor (M7) and moves the lifter rack until the Tray 2 cassette lifter
sensor (SR9) detects it. The lifter lifts, and the lifting plate moves up to the position where the media can
be picked up. The lift operation is performed by monitoring the cassette media-stack-surface sensor
when the printer is turned on, when the cassette is installed, or as needed during a print operation.
If the paper-stack surface sensor does not detect the paper within a specified time after the lifter motor
begins rotating, the DC controller notifies the formatter that the lifter motor has failed.
The DC controller lowers the lifting plate when no printing occurs to prevent media damage and pickup
failure. If a print operation does not occur for a specified time, the DC controller reverses the lifter
motor and moves the lifter rack until the cassette media-stack surface sensor stops detecting it.
Figure 1-34 Cassette lift mechanism
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Cassette paper presence detection
The cassette media-presence sensor detects whether paper is in the cassette.
Figure 1-35 Paper level detection mechanism
46 Chapter 1 Theory of operation ENWW
Cassette media width detection
The paper width 1 sensor (SR10) detects the size of the paper loaded in the cassette. The DC controller
determines the paper size using the paper-width sensor. The paper-width sensor flag moves relative to
the cassette-side paper guide.
The pickup pressure is adjusted according to the paper size to prevent a pickup failure. The pickup
pressure increases when large paper sizes (Letter, A4, and A5-R) are loaded and decreases when
small paper sizes (Executive, B5, A5, A6, and 4 x 6) are loaded.
Figure 1-36 Cassette media width detection
Cassette side paper guide
Media width sensor flag
Automatic close unit
Media width sensor
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Multifeed prevention
In the cassette, a separation roller prevents multiple sheets of paper from entering the paper path. The
cassette pickup roller drives the separation roller through a sheet of paper.
The low friction force between the sheets weakens the driving force from the cassette pickup roller.
Because some braking force is applied to the cassette separation roller, the weak rotational force of the
pickup roller is not enough to rotate the separation roller. Therefore, the separation roller holds back
any multiple-fed sheets, and one sheet of media is fed into the printer.
Figure 1-37 Multifeed prevention
Cassette pickup
roller
Cassette
separation
roller
Normal feed
Media
Lifting plate
Separation roller does not rotate
Multiple feed
48 Chapter 1 Theory of operation ENWW
Multipurpose tray pickup
The multipurpose tray paper-presence sensor detects whether paper is in the tray. If no paper is present,
the DC controller notifies the formatter. Printing does not occur until paper is in the tray.
The sequence of steps for the multipurpose tray pickup operation as follows:
1. After receiving a print command from the formatter, the DC controller reverses the pickup motor,
which causes the multipurpose tray separation roller to rotate.
2. The DC controller turns on the multipurpose tray pickup solenoid (SL3), causing the multipurpose
tray pickup roller to rotate.
3. The multipurpose tray separation roller isolates a single sheet of paper in case more than one
sheet was picked. The single sheet of paper feeds into the product.
The Tray 1 paper sensor (SR21) detects whether the media is present in the MP tray. No printing occurs
if no media is loaded.
Figure 1-38 Multipurpose tray pickup mechanism
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49
Paper feed
After the pickup operation, the paper feeds through the product and into the fuser.
1. The paper passes through the feed rollers. The registration shutter aligns the paper correctly to
2. The DC controller detects the leading edge of paper by the Registration sensor (SR8) and controls
3. The DC controller detects whether or not the media is overhead transparency, using the OHT
4. The toner image on the ITB transfers onto the media, which feeds to the fuser.
Figure 1-39 Paper-feed mechanism
prevent skewed printing.
the rotational speed of the pickup motor to align with the leading edge of image on the ITB.
sensor.
50 Chapter 1 Theory of operation ENWW
Skew-feed prevention
The product can straighten the paper without slowing the feed operation.
1. As the paper enters the paper path, the leading edge strikes the registration shutter, which
straightens the paper. The paper does not pass through the shutter .
2. The feed rollers keep pushing the paper, which creates a force on the leading edge against the
registration shutter.
3. When the force is great enough, the registration shutter opens and the paper passes through.
Figure 1-40 Skew-feed prevention
1
2
3
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51
OHT detection
The OHT sensor detects overhead transparencies. The OHT sensor is a transmission sensor that uses an
LED. The DC controller determines a media mismatch and notifies the formatter when the media type
differs from the media type detected by the OHT sensor. The DC controller turns the LED in the OHT
sensor on and off during the wait or initial rotation period. If the intensity of the light does not match the
specified value, the DC controller determines that the OHT sensor has failed.
Fusing and delivery unit
The fusing and delivery unit fuses the toner onto the paper and delivers the printed page into the output
bin. The following controls ensure optimum print quality:
Loop control
●
Pressure roller pressurization/depressurization control
●
A sensor detects when the output bin is full, and the DC controller notifies the formatter.
Figure 1-41 Fuser and delivery unit
Fuser/delivery block
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Loop control
The loop control monitors the tension of the paper between the second-transfer roller and the fuser.
If the fuser rollers rotate more slowly than the secondary transfer rollers, the paper warp increases
●
and an image defect or paper crease occurs.
If the fuser rollers rotate faster than the secondary transfer rollers, the paper warp decreases and
●
the toner image fails to transfer to the paper correctly, causing color misregistration.
To prevent these problems, the loop sensors, which are located between the secondary transfer rollers
and the fuser rollers, detect whether the paper is sagging or is too taut. The DC controller adjusts the
speed of the fuser motor.
Figure 1-42 Loop-control mechanism
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53
Pressure-roller pressurization control
To prevent excessive wear on the pressure roller and help with jam-clearing procedures, the pressure
roller pressurizes only during printing and standby. The DC controller reverses the fuser motor. The
fuser motor rotates the fuser pressure-release cam.
Figure 1-43 Pressure-roller pressurization control
FUSER MOTOR CONTROL
Fuser motor
FUSER PRESSURE RELEASE signal
Fuser pressure release cam
Fuser sleeve
The pressure roller depressurizes under the following conditions:
The product is turned off with the on/off switch
●
Any failure occurs other than a fuser pressure-release mechanism failure
●
During powersave mode
●
When a paper jam is detected
●
If the DC controller does not sense the fuser pressure-release sensor for a specified period after it
reverses the fuser motor, it notifies the formatter that a fuser pressure-release mechanism failure has
occurred.
NOTE: The fuser remains pressurized if the power is interrupted when the power cord is removed or
the surge protector is turned off, or if the fuser is removed without turning off the product.
54 Chapter 1 Theory of operation ENWW
Duplexing unit (duplex models)
For supported models, the duplexing unit reverses the paper and feeds it through the paper path to
print the second side. The duplexing unit consists of the following components:
Duplexing-reverse unit: Installed on top of the product
●
Duplexing-feed unit: Along the right side
●
The DC controller controls the operational sequence of the duplex block. The DC controller drives each
load, such as motors, solenoid, and clutch, depending on the duplex reverse unit and duplex feed unit
controls.
Figure 1-44 Duplexing unit
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55
Duplexing reverse and feed control
The duplexing reverse procedure pulls the paper into the duplexing unit after it exits the fuser. The
duplexing feed procedure moves the paper through the duplexer so it can enter the product paper path
to print the second side of the page.
1. After the first side has printed, the duplexing flapper solenoid opens, which creates a paper path
into the duplexing-reverse unit.
2. After the paper has fully entered the duplexing-reverse unit, the duplexing-reverse motor reverses
and directs the paper into the duplexing-feed unit.
3. The duplexing re-pickup motor and duplexing feed motor move the paper into the duplexing re-
pickup unit.
4. To align the paper with the toner image on the ITB, the duplexing re-pickup motor stops and the
paper pauses.
5. The paper re-enters the paper path, and the second side prints.
Duplex pickup operation
The product has the following two duplex-media-feed modes depending on the media sizes:
One-sheet mode: Prints one sheet that is printed on two sides in one duplex print operation
●
Two-sheet mode: Prints two sheets that are printed on two-sides in one duplex print operation
●
(maximum paper size is A4)
The formatter specifies the duplex-media-feed mode.
56 Chapter 1 Theory of operation ENWW
Jam detection
The product uses the following sensors to detect the paper as it moves through the paper path and to
report to the DC controller if the paper has jammed.
Fuser output sensor (SR5)
●
Registration sensor (SR8)
●
Fuser loop 1 (SR14)
●
Fuser loop 2 (SR15)
●
Duplexer refeed (SR22)
●
Figure 1-45 Jam detection sensors
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The product determines that a jam has occurred if one of these sensors detects paper at an
inappropriate time. The DC controller stops the print operation and notifies the formatter.
Table 1-17 Jams that the product detects
Jam Description
Pickup delay jam 1 Cassette pickup: The TOP sensor does not detect the leading edge of the paper within a
specified period after the cassette pickup solenoid has turned on.
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Multipurpose tray pickup: The TOP sensor does not detect the leading edge of the paper
within a specified period after the multipurpose tray solenoid has turned on.
Pickup stationary jam The TOP sensor does not detect the trailing edge of the paper within a specified time from
when it detects the leading edge.
Jam detection
57
Table 1-17 Jams that the product detects (continued)
Jam Description
Fuser delivery delay jam The fuser delivery paper-feed sensor does not detect the leading edge of the paper within a
specified period after the TOP sensor detects the leading edge.
Fuser delivery stationary jam The fuser delivery paper-feed sensor does not detect the trailing edge of the paper within a
specified period after it detects the leading edge.
Wrapping jam After detecting the leading edge of the paper, the fuser delivery paper-feed sensor detects the
absence of paper, and it has not yet detected the trailing edge.
Residual paper jam One of the following sensors detects paper presence during the initialization sequence:
Fuser delivery paper-feed sensor
●
TOP senosor
●
Loop sensor 1
●
Loop sensor 2
●
Door open jam A door is open while paper is moving through the product.
Duplexing re-pickup jam 1 The duplex re-pickup sensor does not detect the leading edge of the paper within a specified
period after the media reverse operation starts in the duplex reverse unit.
Duplexing re-pickup jam 2 The TOP sensor does not detect the leading edge of the paper within a specified period after
the paper is re-picked.
After a jam, some sheets of paper might remain inside the product. If the DC controller detects residual
paper after a door closes or after the product is turned on, the product automatically clears itself of
those residual sheets.
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Optional paper feeder
The 1x500-sheet paper feeder is optionally installed at bottom of the printer. The paper feeder picks up
the print media and feeds it to the printer.
NOTE: These optional trays are not identical to the main cassette (Tray 2).
Figure 1-46 Optional paper feeder
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The paper-deck drivers contain a microcomputer and control the paper feeder. The paper-deck drivers
receive commands from the DC controller. If the DC controller is unable to communicate with a paperdeck driver, it notifies the formatter that the optional paper feeders is not connected correctly.
Optional paper feeder
59
Figure 1-47 Signals for the paper feeder
The input trays contain several motors, solenoids, sensors, and switches, as described in the following
table.
Table 1-18 Electrical components for the paper feeder
Component
type
Motors M1 Paper feeder motor
Solenoids SL1 Paper feeder pickup solenoid
Sensors SR1 Tray 3 installed sensor
Switches SW1 Paper feeder cassette media-size switch
Abbreviation Component name
M2 Paper feeder lift motor
SR2 Tray 3 stack surface sensor 2
SR3 Tray 3 paper present sensor
SR4 Tray 3 feed sensor
SW2 Paper-feeder door switch
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Paper-feeder pickup and feed operation
The paper feeder picks up one sheet from the paper-feeder cassette and feeds it to the product.
Figure 1-48 Paper-feeder pickup and feed operation
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Paper size detection and cassette presence detection
The paper-feeder cassette media-size switch (SW1) detects the size of paper loaded in the paper-feeder
cassette. The paper-feeder driver determines the media size by monitoring the combination of the
switches.
Figure 1-49 Paper size detection
Table 1-19 Paper size detection
Paper size Paper-feeder cassette media-size switch settings
Top switch Center switch Bottom switch
62 Chapter 1 Theory of operation ENWW
Universal On On On
Table 1-19 Paper size detection (continued)
Paper size Paper-feeder cassette media-size switch settings
Top switch Center switch Bottom switch
A5
B5 Off On On
Executive On Off On
Letter Off On Off
A4 Off Off On
Legal On On Off
No cassette Off Off Off
On Off Off
The paper-feeder cassette media size switch (SW1) detects whether the paper-feeder cassette is
installed correctly. The paper-feeder driver determines if a cassette is absent when all three switches are
turned off. The paper-feeder driver determines a cassette presence when one of the switches is turned
on.
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Paper feeder cassette lift operation
The cassette lift operation keeps the stack surface of paper at a specified height to maintain stable
media feeding. The paper-feeder driver controls the paper-feeder lifter motor (M2) and monitors the
paper-feeder media stack surface sensors (SR1, SR2) to adjust the stack height when the printer is
turned on, when the printer recovers from sleep mode, when the paper-feeder cassette is installed or as
needed during a print operation. The paper feeder has two paper-feeder media-stack surface sensors.
The paper-feeder media stack surface sensor 1 detects the stack height during a print operation. The
paper-feeder media-stack surface sensor 2 detects the stack height when the printer is turned on, when
the printer recovers from sleep mode and when the paper-feeder cassette is installed. The operational
sequence of the lift operation is as follows:
1. The paper-feeder driver rotates the paper-feeder lifter motor to lift the lifting plate.
2. The paper-feeder driver stops the paper-feeder lifter motor when the paper-feeder media-stack
surface sensor 2 detects the stack surface.
3. The paper-feeder driver rotates the lifter motor again when paper-feeder media stack surface 1
detects that the media surface is lowered during a print operation.
Figure 1-50 Paper-feeder cassette lift
64 Chapter 1 Theory of operation ENWW
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