HP PageWide Enterprise Color 765, PageWide Enterprise Color 780, PageWide Enterprise Color 785 Troubleshooting Manual
HP PageWide Enterprise Color 765 and MFP
780/785
HP PageWide Managed Color E75160 and
MFP E77650/P77660
Troubleshooting Manual
Copyright and License
Trademark Credits
© Copyright 2017 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, 9/2017
Microsoft®, Windows®, Windows® XP, and
Windows Vista® are U.S. registered trademarks
of Microsoft Corporation.
Adobe®, Acrobat®, and PostScript® are
trademarks of Adobe Systems Incorporated.
UNIX® is a registered trademark of The Open
Group.
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 iii
iv Conventions used in this guide ENWW
For additional service and support information
HP service personnel, go to one of the following Web-based Interactive Search Engines (WISE) sites:
AMS
●
https://support.hp.com/wise/home/ams-en
●
https://support.hp.com/wise/home/ams-es
●
https://support.hp.com/wise/home/ams-pt
APJ
●
https://support.hp.com/wise/home/apj-en
●
https://support.hp.com/wise/home/apj-ja
●
https://support.hp.com/wise/home/apj-ko
●
https://support.hp.com/wise/home/apj-zh-Hans
●
https://support.hp.com/wise/home/apj-zh-Hant
EMEA
●
https://support.hp.com/wise/home/emea-en
Channel partners, go to HP Channel Services Network (CSN) at www.hp.com/partners/csn .
At these locations, nd information on the following topics:
●
Install and congure
●
Printer specications
●
Up-to-date control panel message (CPMD) troubleshooting
●
Solutions for printer issues and emerging issues
●
Remove and replace part instructions and videos
●
Service advisories
●
Warranty and regulatory information
Channel partners, access training materials in the HP University and Partner Learning Center at
https://content.ext.hp.com/sites/LMS/HPU.page.
To access HP PartSurfer information from any mobile device, go to http://partsurfermobile.hp.com/ or scan the
Quick Response (QR) code below.
ENWW v
vi For additional service and support information ENWW
Table of contents
1 Theory of operation .................................................................................................................................................................................. 1
Basic operation ......................................................................................................................................................................... 2
Function structure ............................................................................................................................................... 2
Operation sequence ............................................................................................................................................ 4
System control .......................................................................................................................................................................... 6
................................................................................................................................................................................. 6
Formatter and data path .................................................................................................................................... 6
Engine control ...................................................................................................................................................... 8
Pen interface (I/F) .............................................................................................................................................. 10
Power supply ...................................................................................................................................................... 11
AC control module ............................................................................................................................................. 11
Cabling system ....................................................................................................................................................................... 13
Flat Flexible Cables ........................................................................................................................................... 13
FFC routing .......................................................................................................................................................... 16
Discrete cables ................................................................................................................................................... 19
Ground wires ...................................................................................................................................................... 20
Connectors .......................................................................................................................................................... 21
Ferrites ................................................................................................................................................................ 23
Cable management ........................................................................................................................................... 23
Print subsystem ..................................................................................................................................................................... 25
Printhead ............................................................................................................................................................ 25
Printhead air management system ................................................................................................................ 26
Printhead lift ....................................................................................................................................................... 26
Print cartridges .................................................................................................................................................. 26
Optical scan carriage ......................................................................................................................................... 26
Print system operational states ...................................................................................................................... 26
Paper-handling system ......................................................................................................................................................... 29
Printer sensors ................................................................................................................................................... 29
High Capacity Input (HCI) sensors ................................................................................................................... 30
3x550 tray sensors ........................................................................................................................................... 31
1x550 tray sensors ........................................................................................................................................... 32
Inline nisher sensors ....................................................................................................................................... 33
ENWW vii
Printer motors/solenoids ................................................................................................................................. 34
High capacity input (HCI) motors/solenoids .................................................................................................. 35
3x550 tray motors/solenoids .......................................................................................................................... 36
1x550 tray motors/solenoids .......................................................................................................................... 37
Inline nisher motors ........................................................................................................................................ 38
Printer printing system ..................................................................................................................................... 39
Input trays ........................................................................................................................................................... 40
Paper path zones ............................................................................................................................................... 43
Jam detection ..................................................................................................................................................... 45
Servicing system .................................................................................................................................................................... 48
Printhead wiper .................................................................................................................................................. 48
Service uid and aerosol management systems ............................................................................................................. 49
Airow system ........................................................................................................................................................................ 51
Function .............................................................................................................................................................. 51
Heating ................................................................................................................................................................ 51
Airow ................................................................................................................................................................. 51
Modes .................................................................................................................................................................. 51
Components ....................................................................................................................................................... 52
Document feeder system ..................................................................................................................................................... 53
Document feed system .................................................................................................................................... 53
Sensors in the document feeder .................................................................................................................... 53
Document feeder paper path .......................................................................................................................... 54
Document feeder simplex operation ............................................................................................................. 55
Document feeder e-duplex operation ........................................................................................................... 56
Deskew operation ............................................................................................................................................. 57
Document feeder hinges .................................................................................................................................. 57
Scanning and image capture system (780/785) .............................................................................................................. 59
Fax functions and operation ................................................................................................................................................. 60
Computer and network security features ..................................................................................................... 60
PSTN operation .................................................................................................................................................. 60
The fax subsystem ............................................................................................................................................ 60
Fax card in the fax subsystem ......................................................................................................................... 60
Fax page storage in ash memory ................................................................................................................. 62
Output accessories ................................................................................................................................................................ 63
Inline nisher ...................................................................................................................................................... 64
2 Solve problems ....................................................................................................................................................................................... 91
Problem-solving checklist .................................................................................................................................................... 92
Step 1: Check that the printer power is on .................................................................................................... 92
Step 2: Check the control panel for error messages ................................................................................... 92
Step 3: Test print functionality ........................................................................................................................ 93
viii ENWW
Step 4: Test copy functionality (MFP models only) ...................................................................................... 93
Step 5: Test the fax sending functionality (785f/785zs/785z+) ............................................................... 94
Step 6: Test the fax receiving functionality (fax models only) ................................................................... 94
Step 7: Try sending a print job from a computer ......................................................................................... 94
Step 8: Test the Plug and Print USB Drive printing functionality ............................................................... 94
Factors that aect printer performance ........................................................................................................ 94
Troubleshooting process ...................................................................................................................................................... 96
Determine the problem source ....................................................................................................................... 96
Power subsystem .............................................................................................................................................. 98
Tools for troubleshooting ................................................................................................................................................... 129
Print the conguration and printhead information pages ........................................................................ 129
Event log messages ........................................................................................................................................ 132
Tools for troubleshooting: Individual component diagnostics ................................................................ 133
Diagrams .......................................................................................................................................................... 146
Print-quality troubleshooting tools .............................................................................................................. 159
Control panel menus ...................................................................................................................................... 168
Control panel message document (CPMD) ................................................................................................. 243
Print quality troubleshooting guide .................................................................................................................................. 244
Printer pre-checks .......................................................................................................................................... 244
Printer specic image defects ....................................................................................................................... 258
Solve copy/scan problems (780/785) .............................................................................................................................. 297
Solve copy problems (780/785 models only) ............................................................................................ 297
Solve scan problems (780/785 models only) ............................................................................................ 302
Solve paper jam or feed problems ................................................................................................................................... 308
Printer does not pick up paper or misfeeds ................................................................................................ 308
Clear paper jams ............................................................................................................................................. 310
Solve performance problems ............................................................................................................................................ 340
Factors aecting print performance ............................................................................................................ 340
The printer does not print or it prints slowly .............................................................................................. 341
The printer prints slowly ................................................................................................................................ 342
Solve connectivity problems .............................................................................................................................................. 343
Solve USB connection problems ................................................................................................................... 343
Solve wired network problems ..................................................................................................................... 343
Service mode functions ...................................................................................................................................................... 345
Service menu ................................................................................................................................................... 345
Printer resets ................................................................................................................................................... 354
Format Disk and Partial Clean functions ..................................................................................................... 356
Firmware upgrades ............................................................................................................................................................. 359
Determine the installed revision of rmware ............................................................................................. 359
Perform a rmware upgrade ........................................................................................................................ 361
Solve fax problems .............................................................................................................................................................. 365
ENWW ix
Solve email problems ......................................................................................................................................................... 366
Appendix A Printer specications ......................................................................................................................................................... 367
Printer dimensions and weight ......................................................................................................................................... 368
Printer space requirements ............................................................................................................................................... 369
Power consumption, electrical specications, and acoustic emissions ...................................................................... 369
Operating-environment range .......................................................................................................................................... 370
Certicate of Volatility ......................................................................................................................................................... 371
Index ........................................................................................................................................................................................................... 415
x ENWW
List of tables
Table 1-1 Operation sequence ................................................................................................................................................................ 4
Table 1-2 Printbar components ............................................................................................................................................................ 25
Table 1-3 Service Fluid and Aerosol Management System Components ...................................................................................... 50
Table 1-4 Document feeder sensors ................................................................................................................................................... 54
Table 1-5 Document feeder paper path .............................................................................................................................................. 54
Table 2-1 Troubleshooting owchart .................................................................................................................................................. 97
Table 2-2 MPCA LEDs ........................................................................................................................................................................... 100
Table 2-3 MPCA LED sequence at printer power on ....................................................................................................................... 100
Table 2-4 MPCA LEDs ........................................................................................................................................................................... 133
Table 2-5 MPCA LED sequence at printer power on ....................................................................................................................... 134
Table 2-6 ACCM LEDs ........................................................................................................................................................................... 135
Table 2-7 ACCMA LED sequence at printer power on ..................................................................................................................... 135
Table 2-8 Heartbeat LED, product initialization ............................................................................................................................... 136
Table 2-9 Heartbeat LED, product operational ................................................................................................................................ 139
Table 2-10 Reports menu ................................................................................................................................................................... 169
Table 2-11 Settings menu ................................................................................................................................................................... 171
Table 2-12 Copy menu (MFP only) ..................................................................................................................................................... 197
Table 2-13 Scan menu (780/785) ..................................................................................................................................................... 203
Table 2-14 Fax menu (fax models only) ........................................................................................................................................... 231
Table 2-15 Print Options menu .......................................................................................................................................................... 235
Table 2-16 Supplies menu .................................................................................................................................................................. 236
Table 2-17 Trays menu ........................................................................................................................................................................ 237
Table 2-18 Backup/Restore menu ..................................................................................................................................................... 238
Table 2-19 Calibrate/Cleaning menu ................................................................................................................................................. 238
Table 2-20 Troubleshooting menu .................................................................................................................................................... 240
Table 2-21 Printhead health score .................................................................................................................................................... 251
Table 2-22 Solve performance problems ......................................................................................................................................... 340
Table 2-23 Service menu .................................................................................................................................................................... 345
Table A-1 Dimensions for printer base model (SFP; all) ................................................................................................................. 368
Table A-2 Dimensions for base models (780dn, 785f; MFP) ......................................................................................................... 368
Table A-3 Dimensions for 785zs (MFP) ............................................................................................................................................. 368
Table A-4 Dimensions for the 1x550-sheet paper feeder ............................................................................................................. 368
ENWW xi
Table A-5 Dimensions for the 1x550-sheet paper feeder with stand ......................................................................................... 369
Table A-6 Dimensions for the 3x550-sheet paper feeder with stand ......................................................................................... 369
Table A-7 Dimensions for the 4,000-sheet HCI with stand ........................................................................................................... 369
Table A-8 Operating-environment specications ............................................................................................................................ 370
xii ENWW
List of gures
Figure 1-3 FFC insertion line ................................................................................................................................................................. 13
Figure 1-4 FFC support tape ................................................................................................................................................................. 14
Figure 1-5 FFC label ................................................................................................................................................................................ 14
Figure 1-6 FFC wing feature .................................................................................................................................................................. 15
Figure 1-7 ZIF connector ........................................................................................................................................................................ 15
Figure 1-8 FFC hook arm retainers ...................................................................................................................................................... 16
Figure 1-9 FFC pill bump retainers ....................................................................................................................................................... 17
Figure 1-10 FFC die-cut retainers ........................................................................................................................................................ 18
Figure 1-11 FFC double-sided tape retainer ...................................................................................................................................... 18
Figure 1-12 Discrete cable ferrite ........................................................................................................................................................ 19
Figure 1-13 Discrete cable tie-wraps .................................................................................................................................................. 20
Figure 1-14 Ground wires ...................................................................................................................................................................... 21
Figure 1-16 FFC wing feature ............................................................................................................................................................... 22
Figure 1-17 ZIF connector ..................................................................................................................................................................... 23
Figure 1-18 FFC spacing ........................................................................................................................................................................ 24
Figure 1-19 Printhead components ..................................................................................................................................................... 25
Figure 1-20 Print engine sensors ......................................................................................................................................................... 29
Figure 1-21 HCI sensors ........................................................................................................................................................................ 30
Figure 1-22 3x550 Tray sensors .......................................................................................................................................................... 31
Figure 1-23 1x550 tray sensors ........................................................................................................................................................... 32
Figure 1-24 Inline nisher sensors ....................................................................................................................................................... 33
Figure 1-25 HCI motors/solenoids ....................................................................................................................................................... 35
Figure 1-26 3x550 tray motors/solenoids ......................................................................................................................................... 36
Figure 1-27 1x550 tray motors/solenoids ......................................................................................................................................... 37
Figure 1-28 Inline nisher motors ........................................................................................................................................................ 38
Figure 1-29 Printer printing system .................................................................................................................................................... 39
Figure 1-30 Tray 1 pick and separation system ................................................................................................................................ 40
Figure 1-31 Service uid and aerosol management system .......................................................................................................... 50
Figure 1-32 Airow system components ........................................................................................................................................... 52
Figure 1-33 Document feeder sensors ............................................................................................................................................... 54
Figure 1-34 Document feeder paper path .......................................................................................................................................... 54
Figure 1-35 Deskew operation ............................................................................................................................................................. 57
ENWW xiii
Figure 1-36 Document feeder open (book mode) ............................................................................................................................ 58
Figure 1-37 Document feeder open (60º to 80º) .............................................................................................................................. 58
Figure 1-38 FFC insertion line ............................................................................................................................................................... 67
Figure 1-39 FFC support tape ............................................................................................................................................................... 68
Figure 1-40 FFC label ............................................................................................................................................................................. 68
Figure 1-41 FFC hook arm retainers .................................................................................................................................................... 69
Figure 1-42 FFC pill bump retainers .................................................................................................................................................... 70
Figure 1-43 FFC die-cut retainers ........................................................................................................................................................ 71
Figure 1-44 FFC double-sided tape retainer ...................................................................................................................................... 71
Figure 1-45 Discrete cable ferrite ........................................................................................................................................................ 72
Figure 1-46 Discrete cable tie-wraps .................................................................................................................................................. 73
Figure 1-47 Connectors ......................................................................................................................................................................... 74
Figure 1-48 FFC spacing ........................................................................................................................................................................ 75
Figure 1-49 Inline nisher control diagram (front) ............................................................................................................................ 76
Figure 1-50 Inline nisher sensor control diagram (front) ............................................................................................................... 77
Figure 1-51 Inline nisher motor control diagram (front) ................................................................................................................ 78
Figure 1-52 Inline nisher sensor diagram (1 of 2) ........................................................................................................................... 79
Figure 1-53 Inline nisher sensor diagram (2 of 2) ........................................................................................................................... 80
Figure 1-54 Inline nisher motor diagram .......................................................................................................................................... 81
Figure 1-55 Inline nisher stapler control diagram ........................................................................................................................... 82
Figure 1-56 Inline nisher stapler sensor diagram ........................................................................................................................... 83
Figure 1-57 Inline nisher stapler motor control diagram ............................................................................................................... 84
Figure 2-1 MPCA LEDs ......................................................................................................................................................................... 100
Figure 2-2 Formatter heartbeat LED ................................................................................................................................................. 101
Figure 2-3 Diagnostic-tests access button (765 printers) ............................................................................................................. 104
Figure 2-4 Diagnostic-tests access button (780/785 printers) .................................................................................................... 104
Figure 2-5 Press the diagnostics-access button (780/785 printers) ........................................................................................... 105
Figure 2-6 Control panel version A yellow screen ........................................................................................................................... 105
Figure 2-7 Exit the diagnostic mode ................................................................................................................................................. 107
Figure 2-8 Open the Pre-boot menu ................................................................................................................................................. 108
Figure 2-9 Pre-boot menu .................................................................................................................................................................. 109
Figure 2-10 Access the administration menu .................................................................................................................................. 110
Figure 2-11 Access the diagnostics menu ........................................................................................................................................ 110
Figure 2-12 Open the screen test ...................................................................................................................................................... 111
Figure 2-13 Blue vertical gradient screen ........................................................................................................................................ 111
Figure 2-14 Open the touch test ........................................................................................................................................................ 115
Figure 2-15 Touch the white grid ....................................................................................................................................................... 115
Figure 2-16 Verify the mark ............................................................................................................................................................... 116
Figure 2-17 Open the softkey test .................................................................................................................................................... 117
Figure 2-18 Select Home .................................................................................................................................................................... 117
Figure 2-19 Successful test ................................................................................................................................................................ 118
xiv ENWW
Figure 2-20 Open the backlight test .................................................................................................................................................. 119
Figure 2-21 Open the sound test ....................................................................................................................................................... 120
Figure 2-22 Open the keyboard test ................................................................................................................................................. 121
Figure 2-23 Open the sound test ....................................................................................................................................................... 122
Figure 2-24 Touchscreen blank, white, or dim (no image) ............................................................................................................ 124
Figure 2-25 Touchscreen has an unresponsive zone ..................................................................................................................... 125
Figure 2-26 No control panel sound .................................................................................................................................................. 126
Figure 2-27 Home key is unresponsive ............................................................................................................................................ 127
Figure 2-28 Hardware integration pocket (HIP) is not functioning (control panel functional) ................................................ 128
Figure 2-29 Conguration page ......................................................................................................................................................... 129
Figure 2-30 Printhead information page .......................................................................................................................................... 131
Figure 2-31 MPCA LEDs ....................................................................................................................................................................... 133
Figure 2-32 ACCM LEDs ....................................................................................................................................................................... 135
Figure 2-33 Defeating interlocks (cartridge door) .......................................................................................................................... 141
Figure 2-34 Defeating interlocks (left door) .................................................................................................................................... 142
Figure 2-35 Defeating interlocks (right door) .................................................................................................................................. 142
Figure 2-36 Plug/jack locations (external printer) .......................................................................................................................... 146
Figure 2-37 Print engine sensors ...................................................................................................................................................... 148
Figure 2-38 HCI sensors ...................................................................................................................................................................... 149
Figure 2-39 3x550 tray sensors ........................................................................................................................................................ 150
Figure 2-40 1x550 tray sensors ........................................................................................................................................................ 151
Figure 2-41 Inline nisher sensors .................................................................................................................................................... 152
Figure 2-42 Printer motors/solenoids .............................................................................................................................................. 153
Figure 2-43 HCI motors/solenoids ..................................................................................................................................................... 154
Figure 2-44 3x550 tray motors/solenoids ....................................................................................................................................... 155
Figure 2-45 1x550 tray motors/solenoids ....................................................................................................................................... 156
Figure 2-46 Inline nisher motors ..................................................................................................................................................... 157
Figure 2-47 Printer printing system .................................................................................................................................................. 158
Figure 2-50 Ink smear/redeposit ....................................................................................................................................................... 255
Figure 2-51 Print Quality Report page .............................................................................................................................................. 260
Figure 2-52 Print Head Diagnostic Page ........................................................................................................................................... 262
Figure 2-53 Printhead Details page .................................................................................................................................................. 264
Figure 2-67 Paper jam locations (765) ............................................................................................................................................. 310
Figure 2-68 Paper jam locations (780/785) .................................................................................................................................... 312
Figure 2-69 Open the Pre-boot menu .............................................................................................................................................. 355
Figure 2-70 Open the Pre-boot menu .............................................................................................................................................. 357
Figure 2-71 Open the Pre-boot menu .............................................................................................................................................. 358
Figure 2-72 Determine the installed revision of rmware ............................................................................................................ 360
Figure 2-73 Open the Pre-boot menu .............................................................................................................................................. 363
Figure A-1 Certicate of Volatility (750dn; 1 of 3) ........................................................................................................................... 371
Figure A-2 Certicate of Volatility (750dn; 2 of 3) ........................................................................................................................... 372
ENWW xv
Figure A-3 Certicate of Volatility (750dn; 3 of 3) ........................................................................................................................... 373
Figure A-4 Certicate of Volatility (750dw; 1 of 4) .......................................................................................................................... 374
Figure A-5 Certicate of Volatility (750dw; 2 of 4) .......................................................................................................................... 375
Figure A-6 Certicate of Volatility (750dw; 3 of 4) .......................................................................................................................... 376
Figure A-7 Certicate of Volatility (750dw; 4 of 4) .......................................................................................................................... 377
Figure A-8 Certicate of Volatility (772dn; 1 of 3) ........................................................................................................................... 378
Figure A-9 Certicate of Volatility (772dn; 2 of 3) ........................................................................................................................... 379
Figure A-10 Certicate of Volatility (772dn; 3 of 3) ........................................................................................................................ 380
Figure A-11 Certicate of Volatility (772dw; 1 of 4) ........................................................................................................................ 381
Figure A-12 Certicate of Volatility (772dw; 2 of 4) ........................................................................................................................ 382
Figure A-13 Certicate of Volatility (772dw; 3 of 4) ........................................................................................................................ 383
Figure A-14 Certicate of Volatility (772dw; 4 of 4) ........................................................................................................................ 384
Figure A-15 Certicate of Volatility (777z; 1 of 4) ........................................................................................................................... 385
Figure A-16 Certicate of Volatility (777z; 2 of 4) ........................................................................................................................... 386
Figure A-17 Certicate of Volatility (777z; 3 of 4) ........................................................................................................................... 387
Figure A-18 Certicate of Volatility (777z; 4 of 4) ........................................................................................................................... 388
Figure A-19 Certicate of Volatility (75050dn; 1 of 3) .................................................................................................................... 389
Figure A-20 Certicate of Volatility (75050dn; 2 of 3) .................................................................................................................... 390
Figure A-21 Certicate of Volatility (75050dn; 3 of 3) .................................................................................................................... 391
Figure A-22 Certicate of Volatility (75050dw; 1 of 4) ................................................................................................................... 392
Figure A-23 Certicate of Volatility (75050dw; 2 of 4) ................................................................................................................... 393
Figure A-24 Certicate of Volatility (75050dw; 3 of 4) ................................................................................................................... 394
Figure A-25 Certicate of Volatility (75050dw; 4 of 4) ................................................................................................................... 395
Figure A-26 Certicate of Volatility (77740dn; 1 of 3) .................................................................................................................... 396
Figure A-27 Certicate of Volatility (77740dn; 2 of 3) .................................................................................................................... 397
Figure A-28 Certicate of Volatility (77740dn; 3 of 3) .................................................................................................................... 398
Figure A-29 Certicate of Volatility (77740dw; 1 of 4) ................................................................................................................... 399
Figure A-30 Certicate of Volatility (77740dw; 2 of 4) ................................................................................................................... 400
Figure A-31 Certicate of Volatility (77740dw; 3 of 4) ................................................................................................................... 401
Figure A-32 Certicate of Volatility (77740dw; 4 of 4) ................................................................................................................... 402
Figure A-33 Certicate of Volatility (77740z; 1 of 4) ...................................................................................................................... 403
Figure A-34 Certicate of Volatility (77740z; 2 of 4) ...................................................................................................................... 404
Figure A-35 Certicate of Volatility (77740z; 3 of 4) ...................................................................................................................... 405
Figure A-36 Certicate of Volatility (77740z; 4 of 4) ...................................................................................................................... 406
Figure A-37 Certicate of Volatility (77750z; 1 of 4) ...................................................................................................................... 407
Figure A-38 Certicate of Volatility (77750z; 2 of 4) ...................................................................................................................... 408
Figure A-39 Certicate of Volatility (77750z; 3 of 4) ...................................................................................................................... 409
Figure A-40 Certicate of Volatility (77750z; 4 of 4) ...................................................................................................................... 410
Figure A-41 Certicate of Volatility (77760z; 1 of 4) ...................................................................................................................... 411
Figure A-42 Certicate of Volatility (77760z; 2 of 4) ...................................................................................................................... 412
Figure A-43 Certicate of Volatility (77760z; 3 of 4) ...................................................................................................................... 413
xvi ENWW
Figure A-44 Certicate of Volatility (77760z; 4 of 4) ...................................................................................................................... 414
ENWW xvii
xviii ENWW
1 Theory of operation
●
Basic operation
●
System control
●
Cabling system
●
Print subsystem
●
Paper-handling system
●
Servicing system
●
Service uid and aerosol management systems
●
Airow system
●
Document feeder system
●
Scanning and image capture system (780/785)
●
Fax functions and operation
●
Output accessories
ENWW 1
Airflow Assembly
Printhead Lift
Motor
Printhea d
Wiper Mo tor
N
S
Air Pump
Fluid Pump
Vent Soleno id
Air Pump
Motor
Fluid Pump Motor
Drop Detect
Carriage Motor
Image Sensor
Carriage Motor
Fluid Level Sensors
Acumen
Printhead Lift
Sensor
Printhead Lift
Encoder
Aerosol Fan
Motor
Airflow Fan
Motor
Airflow Heater
Airflow Ass embl y
Thermistor
F
Sheet 500 Tray 3
500 Sheet Tray 2
Duplex
Pinch 1
Duplex
Pinch 2
Output
Pinch 1
Ejection
Pinch 1
Output
Pinch 2
Tray 1
Separation
Pinch
Outpu t
Pinch 3
Duplex
Pinch 3
Duplex
Pinch 4
Duplex
Pinch 5
Left Vertical
Pinch 2
Tray 2 Pick
Roller
Tray 3 Pick
Roller
Printhead Assembly
Legend
Pinch roller
Motor
Star Wheel
Media Path
Retard Roller
Switch/Hall
Effect Sensor
Fan/Digital Tach
F
Other Sensors
Torque Coupling
12.13 mm Dia
16.17 mm Dia
PTO connection
150 LPI, 1200 Line
Digital Encoder
Opto Sensor
Solenoid
N
S
Reflective REDI
Basic operation
Function structure
HP recommends printing the following document (on A3 size paper) for troubleshooting reference. It is available
on the HP Web-based Interactive Search Engines (WISE). See HP Web-based Interactive Search Engines (WISE)
on page 3.
Figure 1-1 Printer printing system
2 Chapter 1 Theory of operation ENWW
HP Web-based Interactive Search Engines (WISE)
The printer print system document is available on the HP Web-based Interactive Search Engines (WISE). Go to
the appropriate Web site (listed below), and then search information by printer name.
NOTE: Make sure that this document is printed on A3 size paper.
AMS
●
https://support.hp.com/wise/home/ams-en
●
https://support.hp.com/wise/home/ams-es
●
https://support.hp.com/wise/home/ams-pt
APJ
●
https://support.hp.com/wise/home/apj-en
●
https://support.hp.com/wise/home/apj-ja
●
https://support.hp.com/wise/home/apj-ko
●
https://support.hp.com/wise/home/apj-zh-Hans
●
https://support.hp.com/wise/home/apj-zh-Hant
EMEA
●
https://support.hp.com/wise/home/emea-en
ENWW Basic operation 3
Operation sequence
The engine-control system on the main printed circuit board MPCA controls the operational sequences. The
following table describes the durations and the operations for each period of a print operation from when the
printer is turned on to when the motors stop rotating.
Table 1-1 Operation sequence
Period Duration Purpose
Initial startup and
calibrations
Servicing operations Performed just before the
Print preparation From the time the printer
When the printer is set up for the
rst time from the factory.
NOTE: Startup is disabled if the
temperature is 5°C (41°F) or
lower. The recommend
temperature range for this
function is 15°C (59°F) to 40°C
(104°F).
printhead enters the capped
state after printing, when leaving
the capped state after a print job
is initiated, or during printer idle
times when a print job is not
impacted.
receives a print command until
paper enters the print zone.
This one-time setup process gets the printer ready to print for the rst
time.
●
Fluid replacement—The printer ushes the shipping and
handling uid out of the printhead and replaces it with ink. No
pages are printed.
●
Pen energy calibration (TTOE)—No pages are printed.
●
Die alignment—The printer aligns the 14 die on the printhead
active face, and then prints and internally analyzes one page.
●
Die density leveling—The printer measures and compensates
for the drop variation, and then prints and internally analyzes
multiple pages.
Servicing maintains print quality by removing debris and excess ink.
Nozzle presence detection is employed to replace missing nozzles.
●
Nozzle presence detection—The optical scan carriage detects
and disables inoperable nozzles, and replaces them with
operable nozzles.
●
Printhead servicing—The web wipe on the printhead wiper
moves under the printhead to clean the active face and res the
nozzles into the ink collection unit to clear clogged or blocked
nozzles.
Prepares the printer for a print job.
●
The printhead leaves the capping state as the printhead wiper
moves away from the printhead.
●
If needed, some servicing occurs.
●
The printhead lowers to the printing position. The media type
and printing mode determine the print zone height.
●
The printer picks paper from one of the input trays.
●
Every page from Tray 1 is measured for edge detection. For Tray
2/3 and optional Trays 3, 4 and 5, the printer performs media
edge detection after printing the rst sheet. The last sheet of
each job is also measured for edge detection if at least ve
sheets have been printed.
●
The printer monitors environmental conditions. The printer can
slow the print speed if conditions are signicantly dierent from
a normal oce environment (23°C (73.4°F), 50% relative
humidity).
●
The formatter PCA processes print data and transmits the data
to the printhead.
4 Chapter 1 Theory of operation ENWW
Table 1-1 Operation sequence (continued)
Period Duration Purpose
Printing From the start of media pick in
the designated input tray until
the last sheet is delivered to the
designated output bin.
End of print job Performed after the print job is
completed, and continues until
the next job is initiated.
Processes the print job.
●
The page is picked from the designated tray and travels through
the media path to the print zone.
●
As the page passes under the printhead, the printhead applies
ink to the page.
●
The page then enters the airow assembly area where heated
air might be applied to reduce the moisture content of the page.
●
For Simplex print jobs, the page then proceeds to the output bin
(face-down).
●
For Duplex print jobs, the page then advances until the trailing
edge of the media moves past the left side vertical path sensor.
The page then reverses direction and proceeds down through
the duplex path and underneath the left duplexer (service uid
container). Then the page turns upward, and re-enters the print
zone.
Ink is then applied to the second side of the page by the
printhead.
●
The process continues until all the pages of the print job are
completed. The process might be interrupted by occasional
printhead servicing events if the job includes many pages.
This period puts the printer in a state where it’s ready for the next
print job.
●
After a short dwell interval, the printhead will be allowed to cap.
Standby The printer is sitting idle, waiting
for the next print job to be
initiated.
●
If needed, servicing or nozzle presence detection occurs, but
these events are interruptible if another job is initiated.
●
The printhead moves to the capping position.
●
The printhead wiper moves to cap the printhead.
This period is intended to conserve energy while the printer is sitting
idle. Certain functions might be disabled to save power, and then
restarted when needed. The printer has two standby modes:
●
Idle mode—The printhead is capped and the printer is ready to
immediately start a new job
●
Sleep 1 mode—After the printer is inactive for about 10 minutes
(a setting that can be adjusted from the control panel or the
Embedded Web Server), the control panel turns o and the
power LED blinks to indicate the unit is in Sleep mode. When in
Sleep mode, the printer must wake up and go to idle mode
before all printer functions are available. The printer is designed
to wake up from Sleep mode based on certain interactions with
the printer, such as touching the control panel or opening a
paper tray.
●
Sleep 2 mode-After the printer is inactive for a longer period of
time (typically 2 hours), the engine controller powers down to
minimize power consumptions. This setting can be adjusted
from the control panel.
ENWW Basic operation 5
System control
Power supply
FormaƩer
I/O, PDL, UI Control
Datapath
ASIC + memory
Pen I/F
Pen energy control
Pen voltage sequencing
Signal integrity
Ink-short protecƟon
Ink pumps
Printhead interconnects
Ink supply
Engine control
Motor + sensor drive
Printhead
56,000 nozzles
I/O
AC control
module
Airflow system
The system control coordinates all the other systems, according to commands from the MPCA.
Figure 1-2 System control
●
MPCA
●
Data path
●
Engine control
●
Pen interface
●
Power supply
●
AC control module
MPCA digital ASIC
The MPCA digital ASIC contains dual ARM CPUs (one at 512 MB and one at 600MHz) that execute rmware code
that provides high-level device control. The digital ASIC uses a standard PCle interface to pass data to the
formatter ASIC.
MPCA analog ASIC
The MPCA ASIC generates the system voltage for the MPCA, formatter drives the scanner and ADF motors,
manages the real-time clock, and drives the fax speaker.
Formatter and data path
IMPORTANT: Do not simultaneously install a replacement trusted platform module (TPM), hard disk drive (HDD
MFP), eMMC (SFP) and formatter PCA. Remove and install each part separately, making sure to turn the printer
power on between installations. Failure to do so results in an unusable printer.
The formatter controller ASIC controls the input/output (I/O) control, the user interface, and the rendering of
page description language les into printer-specic commands.
6 Chapter 1 Theory of operation ENWW
Input/output (I/O) control
The printers support 10/100/1000 Ethernet, 802.11 wireless and NFC (some 765 and 780/785 models), a rear
USB host port, a rear USB device port, a walk-up USB host port, and analog fax port (some 780/785 models).
The formatter PCA controls the USB device and USB host. The optional dual USB host port accessory is also
connected to the formatter after user installation.
Wireless and NFC I/O are provided via a separate radio module.
User interface
The printers contain either a 4.3-in (765 models) or an 8-in (780/785 models) color graphics display. For
wireless models, there is an icon on the control panel to denote that the wireless feature is enabled. The printers
include a walk-up USB host port for connection to thumb drives.
Formatter digital ASIC
The formatter digital ASIC has dual ARM CPUs (1.2 GHz) that execute rmware code that provides high-level
device control. The digital ASIC uses a standard PCle interface to pass data to the engine control ASIC. The
formatter rmware is located on either a 320 GB hard-disk drive (HDD) on 780/785 models, or an embedded 8
GHz MultiMedia Card (eMMC) or optional HDD on 765 models.
Additionally, the formatter digital ASIC manages the real-time clock, interfaces to the mass storage controller
ASIC, provides control of USB ports, and interfaces with the Ethernet LAN ASIC and fax module.
Formatter Ethernet ASIC
The formatter Ethernet ASIC connects to the formatter digital ASIC with a PCIe interface to transmit and receive
network packets.
Formatter mass storage ASIC
The formatter mass storage ASIC bridges between the formatter digital ASIC (via PCIe interface) and the mass
storage device (via SATA interface). The 780/785 models use a rotating media HDD, while the 765 models use
eMMC an optional HDD is available.
Formatter memory
Formatter memory is installed on-board and there is support for additional DIMM memory installation. The size
of the memory on the formatter is 1.5 GB for 765 models and 2.5-3.0 GB for 780/785 models. An optional 1GB
DIMM is available as a customer accessory.
Real-time clock
The real-time clock (RTC) allows the fax module to time-stamp outgoing faxes. It also determines the elapsed
time between printhead and ISS calibration events. The RTC uses a separate device connected to the formatter
digital ASIC, along with a crystal and a battery.
Late point dierentiation conguration (LPDC)
Allows the channel partner to congure the speed to the printer depending on the customer’s order. LPDC
conguration is stored on the Trusted Platform Module (TPM). There are three methods to program the speed to
the printer.
ENWW System control 7
●
Automatic
●
O line
●
Manual
Engine control
The engine controller digital ASIC receives high-level commands from the MPCA, and it then provides low-level
control to the print mechanism. In particular, the engine controller digital ASIC and its rmware control motors,
system sensors, and the printhead. The engine controller analog ASICs integrate motor drivers, voltage
regulators, sensor interfaces, and supervisory circuits.
Engine controller digital ASIC
The engine controller digital ASIC has a high-performance 480 MHz ARM CPU and DSP co-processors that
execute rmware code to provide low-level engine control. It also drives a FPGA which then creates the
printhead 15 high-speed LVDS transmission signals. The signals are routed from the engine PCA to the printhead
via two large FFC cables. The engine controller digital ASIC receives pre-rendered data from the MPCA digital
ASIC over a standard PCle interface.
When a printer enters Sleep mode, many functions of the printer go into a low-power mode. If a print job is
received while the printer is in Sleep mode, the printer will take a short period of time to "wake up". This can take
up to 15 seconds, which will delay the rst page out (FPO) time accordingly.
Engine controller analog ASICs
The engine uses six analog ASICs to generate the system voltages for the engine, drive the engine motors,
control various engine sensors, and monitor printhead power delivery for correct operation.
The engine contains 24 motors, 3 solenoids and 2 fans:
NOTE: The air ow fan is created using a DC motor.
Certain models might have fewer motors, depending upon the exact conguration of the paper trays.
Motors
●
Tray 1 pick motor
●
Tray 2 lift motor
●
Tray 3 lift motor
●
Tray 1 separation motor
●
Tray 2 separation motor
●
Tray 3 separation motor
●
Duplex diverter motor
●
Duplex entry motor
●
Duplex exit motor
●
Finisher diverter motor
●
Vertical motor
8 Chapter 1 Theory of operation ENWW
Solenoids
●
Deskew motor (front)
●
Deskew turn motor (back)
●
Scanning carriage motor
●
Stack control motor
●
Printhead wiper motor
●
Eject motor
●
Drop detect carriage motor
●
Print zone feed motor
●
Ink pump motor
●
Ink prime motor
●
Air ow fan motor (for the air ow fan)
●
Printhead lift motor
●
Tray 2 pick solenoid (E-clutch)
●
Tray 3 pick solenoid (E-clutch)
●
Ink prime vent solenoid
Fans
●
Airow fan
Aerosol fan
Most motors are DC motors with encoder feedback, to provide precision servo control. These motors are driven
directly by one of the engine analog ASICs.
The printer uses many sensors to track the media as it travels through the paper path. Most of these are optical
reective edge detection interrupter (REDI) sensors, which are used in conjunction with mirrors to sense the
presence or absence of paper in the paper path. These are carefully aligned and calibrated at the factory, so care
must be taken when servicing these sensors. See the remove and Replace chapter of the Repair manual for
more details.
Other printed circuit assemblies
In addition to hosting the system ASICs, the engine printed circuit assembly (PCA) incorporates many of the
circuits required to interface with sensors and other sub-system components. In some cases, this circuitry is
located on a smaller remote PCAs (SLBs) to optimize cable interconnects. The following table lists the various
PCAs in the base mechanism engine/MPCA.
IMPORTANT: Do not simultaneously install a replacement trusted platform module (TPM), hard disk drive (HDD
MFP), eMMC (SFP) and formatter PCA. Remove and install each part separately, making sure to turn the printer
power on between installations. Failure to do so results in an unusable printer.
ENWW System control 9
Name Description/Function Name Description/Function
Left door PCA Distribution Main bin full sensor PCA Main bin paper out sensor
Printhead lift encoder PCA Printhead lift Heat zone temperature
thermistor PCA
Feed motor encoder PCA Feed motor Contact size detect PCA Paper length/width detect
Left front upper PCA Distribution SIM PCA SHAID and distribution
Air ow assembly PCA Air ow assembly TT dashboard PCA Tabletop control panel interface
Center rear lower PCA Distribution HE1 PCA Hall eect sensor
Left rear lower PCA Distribution Button on/o PCA Base mechanism on/o
AC control module PCA AC control for air ow assembly Power button interface PCA Base mechanism on/o button
Printhead registration sensor
PCA
Main logic PCA MPCA and engine Power button PCA Base mechanism on/o button
Through beam optical drop
detect (TBODD) PCA
Drop detect carriage PCA TBODD carriage Main bin LED PCA Main bin LED
Opto OOP lift plate sensor PCA Tandem tray sensor Hall eect left door PCA Left door hall eect
Separation PCA Tandem tray distribution Temperature/humidity
Printhead sensor eMMC module PCA (8 GB) eMMC module
TBODD sensor Light pipe PCA Light pipe LED
sensor/NVM/HE PCA
Air ow assembly temperature
sense
interface
Multiple sensors
Connector width adjust sensor
PCA
Duplex spittoon contact PCA Duplex spittoon contact Flatbed scan interconnect PCA Flatbed scan interface
Duplex spittoon EEPROM PCA Duplex spittoon EEPROM ADF PCA ADF interface
Right rear lower PCA Distribution eMMC module PCA (16 GB) eMMC module
Left rear upper PCA Distribution Acumen contact PCA Acumen PCA
Pen interface (I/F)
The printhead is the key component that dierentiates this printer from other inkjet printers. The conventional
approach is to print a page in horizontal swaths by moving a “scanning” printhead horizontally over a xed sheet
of paper, advancing the paper a xed amount, and then printing the next swath. This printer moves the paper
underneath a xed page-wide printhead in a single, smooth motion.
Single-pass page-wide printing requires that data and power be delivered to the printhead at a very high rate,
while also maintaining good control of paper position as it moves past the printhead nozzles.
The engine printed circuit assembly (PCA) sends power and data to the printhead via two large at exible cables
(80 pins for the data and 26 pins for the power). The printhead PCA routes power and data to 14 printhead die,
which are attached to the printhead PCA using a exible tab circuit and wire-bonding process.
The printers also contain electronics to control the ink supply station (ISS). The SIM PCA has several functions. It
detects low-ink conditions by detecting presence of ink and/or ink foam in the X-chamber. The SIM PCA also
collects and distributes electrical signals that drive the ink pump and prime motors, engage the solenoids, and
Multi-purpose tray sensor Carriage drop detect motor PCA Motor cable connect
10 Chapter 1 Theory of operation ENWW
read the ink supply acumen data. All data communications between the ISS and engine PCA are routed through a
single 20-pin FFC.
Each ink supply has a memory tag that stores information about its type of ink, the amount of ink remaining, and
other critical data. It uses a special authentication scheme to ensure that only genuine HP supplies are used and
the printer is not damaged by using invalid supplies. Acumen uses a two-line serial bus which, along with 3.3 V
and ground, is cabled via the SIM PCA to the engine PCA and the engine control digital ASIC.
Power supply
The power supply module converts 100-240 VAC to 34 VDC to power the system. The power supply module has
a sleep mode that reduces power consumption in system low-power modes. When in its sleep mode, the power
supply generates less than 20 W.
The power supply module supplies 34 V to the engine PCA. The power supply module has two operating modes,
depending upon the state of its nSLEEP input pin:
●
●
The power supply is a self-contained module that can be replaced if it is defective (see the Remove and Replace
chapter of the Repair manual).
To ensure safe operation, the power supply will “latch o” if a persistent over-current fault condition exists. This
would typically be caused by a short-circuit from 34 V to ground in the printer. Less severe faults can cause the
power supply to latch o, if present for an extended period of time, or if the printer is operated above the
recommended operating temperature range. In addition, the power supply output is split into 7 “rails”, each with
separate output fusing as an additional safety feature.
Printing = up to 170 W ( nSLEEP = high logic level)
Sleep mode = < 20 W ( nSLEEP = low logic level)
NOTE: The power supply includes fusible links for the AC output from the power supply to the AC control
module, and then to the airow assembly.
AC control module
The AC control module performs the following functions related to the heating elements in the air ow
assembly:
●
Low-cost voltage monitor
a. The voltage of the outlet, which the printer is attached, is monitored to ensure the printer remains
operational, even in a low-quality-power environment. This is done by instantly shutting o heater
power until the minimum voltage threshold is met. Hysteresis is included to avoid rapid uctuations in
voltage.
b. This circuit generates a frequency modulated signal that is sent across the isolation barrier, and
interpreted by rmware in the engine.
●
Isolation
–
Isolates the low voltage heater control signals from the high voltage AC power that is applied to the
heater. This is a safety feature to ensure line transients (i.e. lightning) aren’t coupled into the low
voltage system, which could cause damage to the printer or user.
●
AC switch
ENWW System control 11
–
Switches AC power on/o to the heater using TRIACs.
●
Heating Element Conguration
–
Using relays, the heating element conguration is changed between series and parallel, in
coordination with applied voltage. This is done to have a predictable temperature prole that is
functional across the full range of worldwide voltages (90-240VAC).
12 Chapter 1 Theory of operation ENWW
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