HP m454, m479 Service Manual
HP Color LaserJet Pro M454
HP Color LaserJet Pro MFP M479
Service Manual: Troubleshooting
www.hp.com/videos/LaserJet
www.hp.com/support/
colorljM454
www.hp.com/support/colorljM479MFP
HP Color LaserJet Pro M454, HP Color
LaserJet Pro MFP M479
Service Manual: Troubleshooting
Copyright and License
Trademark Credits
© Copyright 2019 HP 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.
Edition 1, 6/2019
Microsoft®, Windows®, Windows® XP, and
Windows Vista® are U.S. registered trademarks
of Microsoft Corporation.
Revision history
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.
Table -1 Revision history
Revision number Revision date Revision notes
1 6/2019 HP LaserJet Pro M454
HP LaserJet Pro MFP M479
Troubleshooting manual initial release
ENWW iii
iv Revision history ENWW
Conventions used in this guide
TIP: Helpful hints or shortcuts.
NOTE: Information that explains a concept or how to complete a task.
Reinstallation tip: Reinstallation helpful hints, shortcuts, or considerations.
IMPORTANT: Information that help the user to avoid potential printer error conditions.
CAUTION: Procedures that the user must follow to avoid losing data or damaging the printer.
WARNING! Procedures that the user must follow to avoid personal injury, catastrophic loss of data, or extensive
damage to the printer.
ENWW v
vi Conventions used in this guide ENWW
HP service and support
Learn about HP access to additional service and support information.
Additional service and support for channel partners
Channel partners, go to partner.hp.com, and then use the steps below to access the HP Web-based Interactive
Search Engine (WISE).
Access WISE for Channel partners
1. Select Services & Support, and then select Services Delivery.
2. Select Technical Support, and then select Technical Documentation.
Find information about the following topics
● Service manuals
● Service advisories
● Up-to-date control panel message (CPMD) troubleshooting
● Install and congure
● Printer specications
● Solutions for printer issues and emerging issues
● Remove and replace part instructions and videos
● Warranty and regulatory information
Additional service and support for HP internal personnel
HP internal personnel, go to one of the following Web-based Interactive Search Engine (WISE) sites:
Americas (AMS)
– https://support.hp.com/wise/home/ams-enWISE - English
– https://support.hp.com/wise/home/ams-esWISE - Spanish
– https://support.hp.com/wise/home/ams-ptWISE - Portuguese
– https://support.hp.com/wise/home/ams-frWISE - French
Asia Pacic / Japan (APJ)
○ https://support.hp.com/wise/home/apj-enWISE - English
○ https://support.hp.com/wise/home/apj-jaWISE - Japanese
○ https://support.hp.com/wise/home/apj-koWISE - Korean
○ https://support.hp.com/wise/home/apj-zh-HansWISE - Chinese (simplied)
○ https://support.hp.com/wise/home/apj-zh-HantWISE - Chinese (traditional)
○ https://support.hp.com/wise/home/apj-thWISE - Thai
Europe / Middle East / Africa (EMEA)
– https://support.hp.com/wise/home/emea-enWISE - English
ENWW vii
viii HP service and support ENWW
Table of contents
1 Theory of operation .................................................................................................................................................................................. 1
HP service and support ........................................................................................................................................................... 1
Additional service and support for channel partners .................................................................................... 1
Additional service and support for HP internal personnel ............................................................................ 1
Basic operation ......................................................................................................................................................................... 2
Sequence of operation ........................................................................................................................................ 4
Formatter-control system ...................................................................................................................................................... 5
Sleep delay ............................................................................................................................................................ 5
Setting up sleep delay ......................................................................................................................................... 5
Printer job language (PJL) ................................................................................................................................... 6
Printer management language (PML) .............................................................................................................. 6
Control panel ........................................................................................................................................................ 6
Walk-up USB ......................................................................................................................................................... 7
Wireless ................................................................................................................................................................. 7
Low end data model (LEDM) overview ............................................................................................................. 7
CPU ......................................................................................................................................................................... 7
Input/output (I/O) ................................................................................................................................................. 7
USB .................................................................................................................................................... 7
USB hosts ......................................................................................................................................... 7
10/100/1000 networking .............................................................................................................. 7
Fax ..................................................................................................................................................... 8
Memory ............................................................................................................................................. 8
Firmware ...................................................................................................................... 8
Nonvolatile random access memory (NVRAM) ...................................................... 8
Flash memory ............................................................................................................. 8
Random access memory ........................................................................................... 8
HP Memory Enhancement technology (MEt) ......................................................... 8
Engine-control unit .................................................................................................................................................................. 8
DC controller ......................................................................................................................................................... 9
High-voltage power supply ............................................................................................................................. 10
Motors ................................................................................................................................................................. 12
Fans ..................................................................................................................................................................... 13
Engine laser/scanner system ............................................................................................................................................... 14
Laser/scanner failure detection ...................................................................................................................... 15
Image-formation system ................................................................................................................................. 16
Image-formation process ............................................................................................................ 19
ENWW ix
Step 1: Primary charging ......................................................................................... 20
Step 2: Laser-beam exposure ................................................................................ 22
Step 3: Development ............................................................................................... 22
Step 4: Primary transfer .......................................................................................... 23
Step 5: Secondary transfer ..................................................................................... 23
Step 6: Separation .................................................................................................... 24
Step 7: Fusing ........................................................................................................... 24
Step 8: Drum cleaning ............................................................................................. 24
Toner cartridges ................................................................................................................................................. 26
Design ............................................................................................................................................. 26
HP Cartridges with JetIntelligence ............................................................................................. 27
HP Cartridge Policy .................................................................................................. 27
Anti-theft or cartridge protection .......................................................................... 27
Memory chip .................................................................................................................................. 28
Dynamic security ........................................................................................................................... 29
Toner seal ....................................................................................................................................... 29
Toner cartridge life detection ...................................................................................................... 29
Developing unit engagement and disengagement control ................................................... 29
Intermediate transfer belt (ITB) unit ............................................................................................................... 30
Secondary transfer roller functions ........................................................................................... 30
Color self calibration ..................................................................................................................... 32
Engine pickup, feed, and delivery system .......................................................................................................................... 33
Photo sensors and switches ............................................................................................................................ 33
Motors, clutches, and solenoids ...................................................................................................................... 35
Feed speed control ....................................................................................................................... 36
Pickup and feed delivery features .............................................................................................. 36
Tray 1 (multipurpose)/Tray 2 (base printer) ................................................................................................. 37
Duplexing unit .................................................................................................................................................... 37
Duplexing reverse and duplex feed control ............................................................................. 38
Duplex pickup operation .............................................................................................................. 38
Jam detection/prevention ................................................................................................................................ 38
Input accessories .................................................................................................................................................................... 40
Tray 3 ................................................................................................................................................................... 40
Tray 3 paper feeder controller .................................................................................................... 40
Tray 3 motor control .................................................................................................................... 41
Tray 3 paper pickup ...................................................................................................................... 41
Tray 3 pickup and feed functions ............................................................................................... 42
Tray 3 jam detection ......................................................................................................................................... 42
Scanning and image capture system .................................................................................................................................. 43
Document feeder system ..................................................................................................................................................... 44
Document feeder simplex operation ............................................................................................................. 44
x ENWW
Fax functions and operation (fax models only) ................................................................................................................. 45
Computer and network security features ..................................................................................................... 45
PSTN operation .................................................................................................................................................. 45
Receive faxes when you hear fax tones ........................................................................................................ 45
Distinctive ring function .................................................................................................................................... 46
Set up the distinctive ring function ............................................................................................ 46
Fax by using voice over IP (VOIP) services ..................................................................................................... 46
The fax subsystem ............................................................................................................................................ 47
Fax card in the fax subsystem ......................................................................................................................... 47
Safety isolation ............................................................................................................................. 47
Safety-protection circuitry .......................................................................................................... 47
Data path ........................................................................................................................................ 48
Hook state ...................................................................................................................................... 48
Downstream device detection .................................................................................................... 48
Hook switch control ...................................................................................................................... 48
Ring detect ..................................................................................................................................... 48
Line current control ...................................................................................................................... 48
Billing or metering tone lters .................................................................................................... 49
Fax page storage in ash memory ................................................................................................................. 49
Stored fax pages ........................................................................................................................... 49
Advantages of ash memory storage ....................................................................................... 49
2 Solve problems ....................................................................................................................................................................................... 51
HP service and support ......................................................................................................................................................... 52
Additional service and support for channel partners .................................................................................. 52
Additional service and support for HP internal personnel .......................................................................... 52
Troubleshooting process ...................................................................................................................................................... 53
Solve problems checklist .................................................................................................................................. 53
Print the menu map ..................................................................................................................... 54
Print a conguration page ........................................................................................................... 54
Print the Printer Status Report (includes a partial event log) ................................................ 55
Determine the problem source ....................................................................................................................... 55
Pre-troubleshooting checklist .................................................................................................... 55
Troubleshooting owchart .......................................................................................................... 56
Power subsystem .............................................................................................................................................. 57
Power-on checks ........................................................................................................................... 57
Power-on troubleshooting overview .................................................................... 57
Control panel checks ......................................................................................................................................... 61
Tools for troubleshooting ..................................................................................................................................................... 62
Individual component diagnostics .................................................................................................................. 62
Tools for troubleshooting: LED diagnostics .............................................................................. 62
ENWW xi
Network port LEDs ................................................................................................... 62
Two-line control panel LEDs ................................................................................... 63
Tools for troubleshooting: Engine diagnostics ......................................................................... 63
Engine test ................................................................................................................ 63
Diagrams ............................................................................................................................................................. 65
Diagrams: Block diagrams ........................................................................................................... 65
Sensors and switches (printer base) ..................................................................... 65
Diagrams: Printed circuit assembly (PCA) connector locations ............................................. 67
Diagrams: Formatter connections ......................................................................... 67
Diagrams: Engine controller PCA connections .................................................... 70
Diagrams: 550-sheet paper feeder controller PCA connections ...................... 72
Diagrams: External plug and port locations ............................................................................. 73
Diagrams: Locations of major components ............................................................................. 74
Major components (printer base) .......................................................................... 74
Motors (printer base) ............................................................................................... 75
Fans (printer base) ................................................................................................... 76
Rollers and power switch (printer base) ............................................................... 76
PCAs (printer base) ................................................................................................... 78
Major components (550-sheet paper feeder) ..................................................... 79
PCA (550-sheet paper feeder) ............................................................................... 79
Motors and rollers (550-sheet paper feeder) ...................................................... 80
Diagrams: Timing chart ................................................................................................................ 81
Diagrams: Circuit diagrams ......................................................................................................... 81
Advanced conguration with HP Embedded Web Server (EWS) and HP Device Toolbox
(Windows) ........................................................................................................................................................... 82
Control panel menus ......................................................................................................................................... 90
2-line control-panel view (M454nw and M454dn models) ................................................... 90
Touchscreen control-panel view (M454dw model) ................................................................. 91
Touchscreen control-panel view (M479 models) .................................................................... 92
Setup menu ................................................................................................................................... 93
Preferences menu .................................................................................................... 93
Network Setup menu .............................................................................................. 95
Wi-Fi Direct menu (wireless models only) ........................................................... 97
Bluetooth low energy menu ................................................................................... 97
Web Services Setup menu ...................................................................................... 97
Tray Management menu ......................................................................................... 98
Paper Setup menu ................................................................................................. 100
Supply Settings menu ........................................................................................... 100
Printer maintenance menu .................................................................................. 101
Print Settings menu ............................................................................................... 103
Power Management menu ................................................................................... 104
xii ENWW
Reports menu ......................................................................................................... 105
Fax Setup menu (M479 models) ......................................................................... 106
Security menu ........................................................................................................ 109
Quick Forms menu ................................................................................................. 109
Function specic menus ............................................................................................................ 110
USB menu ............................................................................................................... 110
Fax Menu (M479 models only) ............................................................................ 110
Copy menu ( M479 models only) ........................................................................ 113
Scan menu (M479 models only) ......................................................................... 115
Apps ......................................................................................................................... 115
Print .......................................................................................................................... 115
Quick sets ................................................................................................................ 115
Hidden menus ............................................................................................................................. 116
Support menu ........................................................................................................ 116
Boot Screen Menu .................................................................................................. 126
Error code and control panel message troubleshooting overview ......................................................... 129
Error codes .................................................................................................................................. 129
How to search for printer documentation .............................................................................. 130
How to search WISE for printer documentation ............................................... 130
How to search GCSN for printer documentation .............................................. 131
Solve image quality problems ........................................................................................................................................... 133
Improve print quality ...................................................................................................................................... 133
Print from a dierent software program ................................................................................ 133
Check the paper-type setting for the print job ...................................................................... 133
Check the paper type setting (Windows) ........................................................... 134
Check the paper type setting (Mac OS X) ........................................................... 134
Check toner-cartridge status .................................................................................................... 134
Print and interpret the print quality page ............................................................................... 135
Clean the printer ......................................................................................................................... 136
Print a cleaning page ............................................................................................. 136
Clean the scanner glass strip and platen ........................................................... 136
Visually inspect the toner cartridge ......................................................................................... 136
Check paper and the printing environment ............................................................................ 136
Step one: Use paper that meets HP specications .......................................... 136
Step two: Check the environment ....................................................................... 137
Calibrate the printer to align the colors .................................................................................. 137
Check other print job settings .................................................................................................. 138
Adjust color settings (Windows) .......................................................................... 138
Try a dierent print driver ......................................................................................................... 139
Print quality troubleshooting guide ............................................................................................................. 140
Repetitive defects ruler ............................................................................................................. 140
ENWW xiii
Use a ruler to measure between repetitive defects ........................................ 140
Print quality of a photo is poor or prints as a gray box. ................................... 143
Clean the printer .................................................................................................................................................................. 143
Print a cleaning page ...................................................................................................................................... 143
Clean the scanner glass strip and platen .................................................................................................... 144
Clean the pickup and separation rollers ...................................................................................................... 145
Clean the pickup rollers and separation pad in the document feeder ................................................... 146
Clean the touchscreen .................................................................................................................................... 147
Solve paper-handling problems ........................................................................................................................................ 147
Printer feeds incorrect page size .................................................................................................................. 147
Printer pulls from incorrect tray ................................................................................................................... 147
Printer will not duplex or duplexes incorrectly .......................................................................................... 147
Paper does not feed from Tray 2 ................................................................................................................. 148
Output is curled or wrinkled .......................................................................................................................... 149
Printer does not pick up paper or misfeeds ................................................................................................ 149
The printer does not pick up paper ......................................................................................... 149
The printer picks up multiple sheets of paper ....................................................................... 149
The document feeder jams, skews, or picks up multiple sheets of paper (M479
models) ........................................................................................................................................ 150
Paper does not feed automatically ......................................................................................... 150
Prevent paper jams ............................................................................................................................................................. 150
Clear paper jams .................................................................................................................................................................. 151
Introduction ...................................................................................................................................................... 151
Experiencing frequent or recurring paper jams? ....................................................................................... 151
Paper jam locations ........................................................................................................................................ 153
Clear paper jams in the document feeder (M479 models only) .............................................................. 154
Clear paper jams in Tray 1 ............................................................................................................................. 156
Clear paper jams in Tray 2 ............................................................................................................................. 159
Clear paper jams in the rear door and the fuser area (simplex models) ............................................... 160
Clear paper jams in the output bin ............................................................................................................... 162
Clear paper jams in the duplexer (duplex models) .................................................................................... 163
Solve performance problems ............................................................................................................................................ 164
Solve connectivity problems .............................................................................................................................................. 164
Solve USB connection problems ................................................................................................................... 164
Solve wired network problems ..................................................................................................................... 164
Introduction ................................................................................................................................. 164
Poor physical connection .......................................................................................................... 165
The computer is using the incorrect IP address for the printer .......................................... 165
The computer is unable to communicate with the printer .................................................. 165
The printer is using incorrect link and duplex settings for the network ............................ 165
New software programs might be causing compatibility problems .................................. 166
xiv ENWW
The computer or workstation might be set up incorrectly .................................................. 166
The printer is disabled, or other network settings are incorrect ........................................ 166
Solve wireless network problems ................................................................................................................ 166
Introduction ................................................................................................................................. 166
Wireless connectivity checklist ................................................................................................. 166
The printer does not print after the wireless conguration completes ............................ 167
The printer does not print, and the computer has a third-party rewall installed .......... 167
The wireless connection does not work after moving the wireless router or printer ..... 167
Cannot connect more computers to the wireless printer .................................................... 167
The wireless printer loses communication when connected to a VPN .............................. 168
The network does not appear in the wireless networks list ............................................... 168
The wireless network is not functioning ................................................................................. 168
Perform a wireless network diagnostic test .......................................................................... 168
Reduce interference on a wireless network .......................................................................... 168
Service/Support menus and Repair Mode functions ..................................................................................................... 169
Service menu ................................................................................................................................................... 169
Support menu .................................................................................................................................................. 174
Printer resets ................................................................................................................................................... 179
Restore the factory-set defaults ............................................................................................. 179
Semi-full reset ............................................................................................................................ 179
OOBE or Cold reset ..................................................................................................................... 180
Repair Mode ..................................................................................................................................................... 180
When using toner cartridges multiple times .......................................................................... 180
Solve fax problems (MFP models only) ............................................................................................................................ 181
Checklist for solving fax problems ............................................................................................................... 181
Perform a fax diagnostic test ........................................................................................................................ 183
Solve general fax problems ........................................................................................................................... 183
Faxes are sending slowly .......................................................................................................... 183
Fax quality is poor ...................................................................................................................... 184
You touched the Cancel button to cancel a fax, but the fax was still sent .................. 185
Not able to locate the fax settings in HP Web Jetadmin ...................................................... 185
The header is appended to the top of the page when the overlay option is enabled .... 185
A mix of names and numbers is in the recipient's box ......................................................... 185
A one-page fax prints as two pages ........................................................................................ 185
A document stops in the document feeder in the middle of faxing ................................... 185
The volume for sounds coming from the fax accessory is too high or too low ............... 185
Use fax over VoIP networks ...................................................................................................... 185
Solve problems receiving faxes .................................................................................................................... 186
Solve problems sending faxes ...................................................................................................................... 190
Fax error messages on the control panel ................................................................................................... 191
The No Fax Detected message displays ................................................................................. 191
ENWW xv
The Communication error message appears ........................................................................ 191
No Dial Tone ................................................................................................................................ 192
The Fax is busy message appears ........................................................................................... 193
The No fax answer message appears ..................................................................................... 193
Document feeder paper jam .................................................................................................... 193
The Fax storage is full message appears ............................................................................... 194
Scanner error .............................................................................................................................. 194
The control panel displays a Ready message with no attempt to send the fax .............. 194
The control panel displays the message "Storing page 1" and does not progress
beyond that message ................................................................................................................ 194
Faxes can be received, but not sent ........................................................................................ 194
Printer is password protected .................................................................................................. 195
Unable to use fax functions from the control panel ............................................................. 195
Unable to use speed dials ......................................................................................................... 195
Unable to use group dials ......................................................................................................... 195
Receive a recorded error message from the phone company when trying to send a
fax ................................................................................................................................................. 196
Unable to send a fax when a phone is connected to the printer ........................................ 196
Troubleshoot fax codes and trace reports .................................................................................................. 196
View and interpret fax error codes .......................................................................................... 196
Fax trace report .......................................................................................................................... 197
Fax logs and reports ....................................................................................................................................... 198
Print all fax reports .................................................................................................................... 198
Print individual fax reports ........................................................................................................ 198
Set the fax error report ............................................................................................................. 198
Set the fax-error-correction mode ............................................................................................................... 199
Change the fax speed ..................................................................................................................................... 199
Use fax on a DSL, PBX, or ISDN system ....................................................................................................... 199
DSL ................................................................................................................................................ 200
PBX ............................................................................................................................................... 200
ISDN .............................................................................................................................................. 200
Solve email problems ......................................................................................................................................................... 200
Cannot connect to the email server ............................................................................................................. 200
Validate the SMTP gateway (Windows) ....................................................................................................... 201
Validate the LDAP gateway (Windows) ........................................................................................................ 201
Update the rmware ........................................................................................................................................................... 201
Method one: Update the rmware using the control panel ..................................................................... 201
Method two: Update the rmware using the Firmware Update Utility .................................................. 202
Appendix A Certicates of volatility ...................................................................................................................................................... 203
Certicates of volatility ....................................................................................................................................................... 204
xvi ENWW
Index ........................................................................................................................................................................................................... 211
ENWW xvii
xviii ENWW
List of tables
Table 1-1 Sequence of operation ........................................................................................................................................................... 4
Table 1-2 Printer electrical components ............................................................................................................................................... 9
Table 1-3 Motors1 .................................................................................................................................................................................... 12
Table 1-4 Fans ......................................................................................................................................................................................... 13
Table 1-8 Toner cartridge control functions ....................................................................................................................................... 26
Table 1-9 Secondary transfer roller functions ................................................................................................................................... 30
Table 1-10 Calibration functions .......................................................................................................................................................... 32
Table 1-11 Photo sensors and switches ............................................................................................................................................. 34
Table 1-13 Print mode and feed speed ............................................................................................................................................... 36
Table 1-14 Print mode and feed speed ............................................................................................................................................... 36
Table 1-15 Tray 3 paper feeder electrical components ................................................................................................................... 41
Table 1-16 Tray 3 motor control .......................................................................................................................................................... 41
Table 1-17 Pickup feed components (1x550-sheet paper feeder) ................................................................................................ 42
Table 2-1 Troubleshooting owchart .................................................................................................................................................. 56
Table 2-2 Formatter connections M454nw/dn models .................................................................................................................... 67
Table 2-3 Formatter connections M454dw model ............................................................................................................................ 68
Table 2-4 Formatter connections M479fnw/fdn/fdw models ......................................................................................................... 68
Table 2-5 Formatter connections M479dw models .......................................................................................................................... 69
Table 2-6 Engine controller PCA connectors ...................................................................................................................................... 70
Table 2-7 550-sheet paper feeder controller PCA connectors ....................................................................................................... 72
Table 2-8 Major components (printer base) ....................................................................................................................................... 74
Table 2-9 Motors (printer base) ............................................................................................................................................................ 75
Table 2-10 Fans (printer base) .............................................................................................................................................................. 76
Table 2-11 Rollers and power switch (printer base) ......................................................................................................................... 76
Table 2-12 PCAs (printer base) ............................................................................................................................................................. 78
Table 2-13 Major components (550-sheet paper feeder) ............................................................................................................... 79
Table 2-14 PCA (550-sheet paper feeder) .......................................................................................................................................... 79
Table 2-15 Motors and rollers (550-sheet paper feeder) ................................................................................................................ 80
Table 2-16 Preferences menu .............................................................................................................................................................. 93
Table 2-17 Network Setup menu ......................................................................................................................................................... 95
Table 2-18 Wi-Fi Direct menu ............................................................................................................................................................... 97
Table 2-19 Bluetooth menu .................................................................................................................................................................. 97
Table 2-20 HP Web Services menu ...................................................................................................................................................... 97
Table 2-21 Tray management menu ................................................................................................................................................... 98
Table 2-22 Paper setup menu ............................................................................................................................................................ 100
Table 2-23 Supply settings menu ...................................................................................................................................................... 100
ENWW xix
Table 2-24 Printer maintenance menu ............................................................................................................................................. 101
Table 2-25 Print Settings menu ......................................................................................................................................................... 103
Table 2-26 Power management menu ............................................................................................................................................. 104
Table 2-27 Reports menu ................................................................................................................................................................... 105
Table 2-28 Fax Setup menu ................................................................................................................................................................ 106
Table 2-29 Security menu ................................................................................................................................................................... 109
Table 2-30 Quick Forms menu ........................................................................................................................................................... 109
Table 2-31 USB menu .......................................................................................................................................................................... 110
Table 2-32 Fax Menu ............................................................................................................................................................................ 110
Table 2-33 Copy menu ......................................................................................................................................................................... 113
Table 2-34 Scan menu ......................................................................................................................................................................... 115
Table 2-35 Support Menu ................................................................................................................................................................... 116
Table 2-36 Service menu .................................................................................................................................................................... 122
Table 2-37 Boot screen menu ............................................................................................................................................................ 127
Table 2-38 ERROR CODES: The rst two characters ....................................................................................................................... 129
Table 2-40 Solve performance problems ......................................................................................................................................... 164
Table 2-41 Service menu .................................................................................................................................................................... 169
Table 2-42 Support Menu ................................................................................................................................................................... 174
Table 2-43 Solve problems receiving faxes ..................................................................................................................................... 186
Table 2-44 Solve problems sending faxes ....................................................................................................................................... 190
xx ENWW
List of gures
Figure 1-3 High-voltage power supply ................................................................................................................................................ 11
Figure 1-9 Primary charging ................................................................................................................................................................. 21
Figure 1-10 Laser-beam exposure ...................................................................................................................................................... 22
Figure 1-11 Development ..................................................................................................................................................................... 22
Figure 1-12 Primary transfer ................................................................................................................................................................ 23
Figure 1-13 Secondary transfer ........................................................................................................................................................... 23
Figure 1-14 Separation .......................................................................................................................................................................... 24
Figure 1-15 Fusing .................................................................................................................................................................................. 24
Figure 1-16 Drum cleaning .................................................................................................................................................................... 25
Figure 1-17 Toner cartridge block diagram ........................................................................................................................................ 26
Figure 1-20 Photo sensors and switches ........................................................................................................................................... 34
Figure 1-22 Jam detection sensors ..................................................................................................................................................... 39
Figure 1-24 Tray 3 paper feeder controller ........................................................................................................................................ 41
Figure 1-25 Paper pickup and feed operation (550-sheet paper feeder) ..................................................................................... 42
Figure 1-26 Jam detection sensors (Tray 3) ...................................................................................................................................... 43
Figure 2-1 Engine test page .................................................................................................................................................................. 58
Figure 2-2 Engine test page .................................................................................................................................................................. 59
Figure 2-3 Engine test page .................................................................................................................................................................. 61
Figure 2-4 Engine test page .................................................................................................................................................................. 64
Figure 2-5 Sensors and switches (printer base) ................................................................................................................................ 65
Figure 2-6 Sensors and switches (550-sheet paper feeder) ........................................................................................................... 66
Figure 2-7 Formatter connections M454nw/dn models .................................................................................................................. 67
Figure 2-8 Formatter connections M454dw model .......................................................................................................................... 68
Figure 2-9 Formatter connections M479fnw/fdn/fdw models ....................................................................................................... 68
Figure 2-10 Formatter connections M479dw models ...................................................................................................................... 69
Figure 2-11 Engine controller PCA connectors .................................................................................................................................. 70
Figure 2-12 550-sheet paper feeder controller PCA connectors ................................................................................................... 72
Figure 2-13 Major components (printer base) ................................................................................................................................... 74
Figure 2-14 Motors (printer base) ........................................................................................................................................................ 75
Figure 2-15 Fans (printer base) ............................................................................................................................................................ 76
Figure 2-16 Rollers and power switch (printer base) ........................................................................................................................ 76
Figure 2-17 PCAs (printer base) ........................................................................................................................................................... 78
Figure 2-18 Major components (550-sheet paper feeder) .............................................................................................................. 79
Figure 2-19 PCA (550-sheet paper feeder) ........................................................................................................................................ 79
Figure 2-20 Motors and rollers (550-sheet paper feeder) ............................................................................................................... 80
Figure 2-21 General timing chart ......................................................................................................................................................... 81
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Figure 2-22 General circuit diagram (printer base) ........................................................................................................................... 82
Figure 2-23 Sample product search criteria .................................................................................................................................... 131
Figure 2-24 Print quality page ............................................................................................................................................................ 135
Figure 2-25 Examples of repetitive defects ..................................................................................................................................... 141
Figure 2-26 Place the ruler on the page ........................................................................................................................................... 142
Figure 2-27 Locate the next repetitive defect ................................................................................................................................. 142
Figure 2-28 Determine the defective assembly .............................................................................................................................. 143
Figure A-1 Certicate of volatility M454 non-wireless (1 of 2) ..................................................................................................... 204
Figure A-2 Certicate of volatility M454 wireless (1 of 2) .............................................................................................................. 205
Figure A-3 Certicate of volatility M454 wireless (2 of 2) .............................................................................................................. 206
Figure A-4 Certicate of volatility M479 non-wireless (1 of 2) ..................................................................................................... 207
Figure A-5 Certicate of volatility M479 non-wireless (2 of 2) ..................................................................................................... 208
Figure A-6 Certicate of volatility M479 wireless (1 of 2) .............................................................................................................. 209
Figure A-7 Certicate of volatility M479 wireless (2 of 2) .............................................................................................................. 210
xxii ENWW
1 Theory of operation
●
HP service and support
●
Basic operation
●
Formatter-control system
●
Engine-control unit
●
Engine laser/scanner system
●
Engine pickup, feed, and delivery system
●
Input accessories
●
Scanning and image capture system
●
Document feeder system
●
Fax functions and operation (fax models only)
HP service and support
Learn about HP access to additional service and support information.
Additional service and support for channel partners
Channel partners, go to partner.hp.com, and then use the steps below to access the HP Web-based Interactive
Search Engine (WISE).
Access WISE for Channel partners
1. Select Services & Support, and then select Services Delivery.
2. Select Technical Support, and then select Technical Documentation.
Find information about the following topics
● Service manuals
● Service advisories
● Up-to-date control panel message (CPMD) troubleshooting
● Install and congure
● Printer specications
● Solutions for printer issues and emerging issues
● Remove and replace part instructions and videos
● Warranty and regulatory information
Additional service and support for HP internal personnel
HP internal personnel, go to one of the following Web-based Interactive Search Engine (WISE) sites:
ENWW HP service and support 1
Americas (AMS)
– https://support.hp.com/wise/home/ams-enWISE - English
– https://support.hp.com/wise/home/ams-esWISE - Spanish
– https://support.hp.com/wise/home/ams-ptWISE - Portuguese
– https://support.hp.com/wise/home/ams-frWISE - French
Asia Pacic / Japan (APJ)
– https://support.hp.com/wise/home/apj-enWISE - English
– https://support.hp.com/wise/home/apj-jaWISE - Japanese
– https://support.hp.com/wise/home/apj-koWISE - Korean
– https://support.hp.com/wise/home/apj-zh-HansWISE - Chinese (simplied)
– https://support.hp.com/wise/home/apj-zh-HantWISE - Chinese (traditional)
– https://support.hp.com/wise/home/apj-thWISE - Thai
Europe / Middle East / Africa (EMEA)
– https://support.hp.com/wise/home/emea-enWISE - English
Basic operation
The printer routes all high-level processes through the formatter, which stores font information, processes the
print image, and communicates with the host computer.
The basic printer operation comprises the following systems:
● Engine control system
● Laser scanner system
● Image-formation system
● Pickup, feed, and delivery system
● Accessory (optional paper feeder)
● Integrated scanner system (M479 models only)
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Figure 1-1 Relationship between the main printer systems
Laser scanner system
Image-formation system
Pickup, feed and delivery system
Accessory
Scanner system (M479 models)only)
Formatter
Engine-control system
DC controller
Low-voltage power supply
High-voltage power supply
Fuser control
Engine-control unit
ENWW Basic operation 3
Sequence of operation
The DC controller PCA controls the operating sequence, as described in the following table.
Table 1-1 Sequence of operation
Period Duration Description
Waiting From the time the power is turned on, the door is
closed, or when the printer exits sleep mode until the
printer is ready for printing.
Standby From the end of the waiting sequence, the last rotation
until the formatter receives a print command, or until
the printer is turned o.
Initial rotation From the time the formatter receives a print command
until the paper enters the paper path.
● Heats the fuser roller in the fuser
● Pressurizes the fuser lm
● Detects the toner cartridges
● Separates all of the developing rollers from the
photosensitive drums in the toner cartridges
● Rotates and stops each motor
● Cleans the intermediate transfer belt (ITB) and
secondary transfer roller
●
Detects cable breakage on the thermistor
● Rotates and stops each fan
● Detects any residual paper in the engine
● Is in the Ready state
● Enters Sleep mode if the formatter sends the
sleep command
● The printer calibrates if it is time for an automatic
calibration
● Rotates each motor
● Rotates each fan
● Activates the high-voltage power supply
Printing From the time the rst sheet of paper enters the paper
path until the last sheet has passed through the fuser.
Last rotation From the time the last sheet of paper exits the fuser
until the motors stop rotating.
● Prepares the laser/scanner unit
● Warms the fuser to the correct temperature
● Forms the image on the photosensitive drums
● Transfers the toner to the paper
● Fuses the toner image onto the paper
● Moves the last printed sheet into the output bin
● Stops each motor
● Stops the high-voltage power supply
● Stops the laser/scanner unit
● Turns the fuser heater o
● Cleans the ITB and secondary transfer roller
● If another print command is received, the printer
enters the initial rotation period when the last
rotation is complete.
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Formatter-control system
The formatter performs the following functions:
● Controlling the sleep delay function
● Receiving and processing print data from the various printer inputs
● Monitoring control-panel functions and relaying printer status information (through the control panel and
the bidirectional input/output)
● Developing and coordinating data placement and timing with the DC controller PCA
● Stores font information
● Communicates with the host computer through the network or the bidirectional interface
The formatter receives a print job from the network or bidirectional interface and separates it into image
information and instructions that control the printing process. The DC controller PCA synchronizes the image
formation system with the paper input and output systems, and then signals the formatter to send the print
image data.
Sleep delay
When the printer is in sleep delay mode, the control-panel backlight is turned o, but the printer retains all
printer settings, downloaded fonts, and macros. The default setting is a 1-minute idle time. The setting can be
changed from the control panel menus.
The printer exits sleep delay mode and enters the warm-up cycle when any of the following occurs.
● A print job, valid data, or a PML or PJL command is received at the serial port.
● The control panel is touched (button press or touchscreen touch depending on model).
● Inserting paper into the ADF will wake up the device. Opening the scanner lid will not wake up the device.
There is no sensor for the scanner lid open. (M479 only).
● Quick press on the power button.
● Connecting the ethernet cable to a live network.
● Connecting the fax cable to a live phone line.
● Inserting a USB drive in either the front USB port or the USB port on the back of the device.
● Opening the front door.
● Opening the rear door.
● Connecting a USB cable to a PC that is powered on.
NOTE: Opening the paper tray will not wake up the device.
TIP: Error messages override the sleep delay message. The printer enters sleep mode at the appropriate time,
but the error message continues to appear.
Setting up sleep delay
ENWW Formatter-control system 5
2-line control panels
1. On the product control panel, press the OK button. Then use or to navigate to Power Management, and
then select OK then use the or to navigate to Settings.
2. Open the following menus:
● Power Management
3. Use the arrow keys to select the time for the Sleep Delay , and then press the OK button.
Touchscreen control panels
1. From the Home screen on the product control panel, swipe down, and then select Setup button.
2. Open the following menus:
● Power Management
● Sleep Delay
3. Select the time for the Sleep Delay.
Printer job language (PJL)
PJL is an integral part of printer conguration, in addition to the standard PCL and PostScript (PS). With standard
cabling, the printer can use PJL to perform a variety of functions.
● Dynamic I/O switching: The printer can be congured with a host on each I/O by using dynamic I/O
switching. Even when the printer is oine, it can receive data from more than one I/O simultaneously, until
the I/O buer is full.
● Context-sensitive switching: The printer can automatically recognize the personality (PS or PCL) of each job
and congure itself to serve that personality.
● Isolation of print environment settings from one print job to the next: For example, if a print job is sent to
the printer in landscape mode, the subsequent print jobs print in landscape only if they are formatted for
landscape printing.
Printer management language (PML)
PML allows remote conguration of the printer and status monitoring through the input/output (I/O) ports.
Control panel
The formatter sends and receives printer status and command data to and from the control panel.
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