HP m125, m126, m127, m128 Troubleshooting Manual
LASERJET PRO MFP
Troubleshooting Manual
M125-126 M127-128 M127-128
HP LaserJet Pro MFP M125, M126, M127,
M128
Troubleshooting Manual
Copyright and License
Trademark Credits
© 2013 Copyright Hewlett-Packard
Development Company, L.P.
Reproduction, adaptation, or translation
without prior written permission is prohibited,
except as allowed under the copyright laws.
The information contained herein is subject to
change without notice.
The only warranties for HP products and
services are set forth in the express warranty
statements accompanying such products and
services. Nothing herein should be construed
as constituting an additional warranty. HP shall
not be liable for technical or editorial errors or
omissions contained herein.
Part number: CZ183-90907
Edition 1, 9/2013
Microsoft®, Windows®, Windows® XP, and
Windows Vista® are U.S. registered trademarks
of Microsoft Corporation.
Conventions used in this guide
TIP: Tips provide helpful hints or shortcuts.
NOTE: Notes provide important information to explain a concept or to complete a task.
CAUTION: Cautions indicate procedures that you should follow to avoid losing data or damaging the
product.
WARNING! Warnings alert you to specific procedures that you should follow to avoid personal injury,
catastrophic loss of data, or extensive damage to the product.
ENWW iii
iv Conventions used in this guide ENWW
Table of contents
1 Theory of operation ....................................................................................................................................... 1
Basic operation ...................................................................................................................................................... 2
Major product systems ........................................................................................................................ 2
Product block diagram ........................................................................................................................ 2
Sequence of operation ........................................................................................................................ 3
Normal sequence of operation ......................................................................................... 3
Formatter-control system ..................................................................................................................................... 4
Sleep mode .......................................................................................................................................... 4
Input/output ........................................................................................................................................ 4
CPU ....................................................................................................................................................... 4
Memory ................................................................................................................................................ 4
Firmware ........................................................................................................................... 5
PJL overview ........................................................................................................................................ 5
LEDM overview .................................................................................................................................... 5
ACL overview ....................................................................................................................................... 5
Control panel ....................................................................................................................................... 5
Engine-control system .......................................................................................................................................... 6
Motors, solenoids, switches, and sensors .......................................................................................... 7
DC controller operations ................................................................................................................... 10
Fuser-control circuit .......................................................................................................................... 11
Fuser failure detection ................................................................................................... 12
Fuser temperature control ............................................................................................. 13
Fuser protective function ............................................................................................... 14
Pressure roller cleaning .................................................................................................. 14
Low-voltage power supply ............................................................................................................... 15
Over-current/over-voltage protection .......................................................................... 17
High-voltage power supply ............................................................................................................... 18
Laser/scanner system ....................................................................................................................... 19
Laser failure detection .................................................................................................... 19
Image-formation system .................................................................................................................................... 21
Electrophotographic process ............................................................................................................ 21
Image formation process .................................................................................................................. 23
ENWW v
Latent-image formation stage ....................................................................................... 24
Primary charging .......................................................................................... 24
Laser beam exposure ................................................................................... 24
Developing stage ............................................................................................................ 25
Toner cartridge ............................................................................................. 25
Transfer stage ................................................................................................................. 26
Fusing stage ................................................................................................. 26
Cleaning stage .............................................................................................. 27
Pickup, feed, and delivery system ...................................................................................................................... 28
Photo sensors, motor, and solenoid ................................................................................................. 29
Jam detection .................................................................................................................................... 30
Scanner system ................................................................................................................................................... 31
Electrical system ............................................................................................................................... 31
Scanner power-on sequence of events .......................................................................... 31
Copy or scan-to-computer sequence of events ............................................................. 32
Document feeder functions and operation ......................................................................................................... 33
Document feeder operation .............................................................................................................. 33
Document feeder paper path and document feeder sensors .......................................................... 33
Document feeder jam detection ....................................................................................................... 34
Fax functions and operation ............................................................................................................................... 35
Computer and network security features ........................................................................................ 35
PSTN operation ................................................................................................................................. 35
The fax subsystem ............................................................................................................................ 35
Fax card in the fax subsystem .......................................................................................................... 35
Safety isolation ............................................................................................................... 36
Safety-protection circuitry ............................................................................................. 36
Data path ......................................................................................................................... 36
Hook state ....................................................................................................................... 36
Downstream device detection ........................................................................................ 37
Hook switch control ........................................................................................................ 37
Ring detect ...................................................................................................................... 37
Line current control ........................................................................................................ 37
Billing- (metering-) tone filters ...................................................................................... 37
Fax page storage in flash memory ................................................................................................... 37
Stored fax pages ............................................................................................................. 38
Advantages of flash memory storage ............................................................................ 38
2 Solve problems ........................................................................................................................................... 39
Solve problems checklist ..................................................................................................................................... 40
Troubleshooting process .................................................................................................................................... 42
Determine the problem source ......................................................................................................... 42
vi ENWW
Power subsystem .............................................................................................................................. 43
Power-on checks ............................................................................................................ 43
Tools for troubleshooting ................................................................................................................................... 44
Component diagnostics .................................................................................................................... 44
Engine diagnostics .......................................................................................................... 44
Engine-test page .......................................................................................... 44
Drum rotation functional check .................................................................. 44
Half self-test functional check ..................................................................... 44
Diagrams ........................................................................................................................................... 46
Plug/jack locations ......................................................................................................... 46
Location of connectors ................................................................................................... 47
Locations of major components ..................................................................................... 48
General timing chart ....................................................................................................... 53
General circuit diagram .................................................................................................. 54
Internal print-quality test pages ...................................................................................................... 55
Clean the paper path ....................................................................................................... 55
Print the configuration page .......................................................................................... 55
Print-quality troubleshooting tools ................................................................................................. 57
Repetitive defect ruler .................................................................................................... 57
Control panel menus ......................................................................................................................... 58
Touchscreen control panel ............................................................................................. 58
Setup menu .................................................................................................. 58
Fax Menu ....................................................................................................... 65
Copy Menu .................................................................................................... 67
LCD control panel ............................................................................................................ 69
Setup menu .................................................................................................. 69
Copy menu .................................................................................................... 77
Interpret control-panel messages .................................................................................................... 79
Control-panel message types ........................................................................................ 79
Control-panel messages ................................................................................................ 79
Clear jams ............................................................................................................................................................ 86
Solve paper feed or jam problems .................................................................................................... 86
The product does not pick up paper ............................................................................... 86
The product picks up multiple sheets of paper .............................................................. 86
Frequent or recurring paper jams .................................................................................. 86
Prevent paper jams ......................................................................................................... 87
Clear jams from the input tray .......................................................................................................... 88
Clear jams in the toner-cartridge area ............................................................................................. 91
Clear jams in the output bin .............................................................................................................. 94
Clear jams in the document feeder ................................................................................................... 97
Solve paper-handling problems .......................................................................................................................... 99
ENWW vii
Solve image-quality problems .......................................................................................................................... 100
General print-quality issues ........................................................................................................... 100
Copy print-quality problems ........................................................................................................... 104
Scan-quality problems .................................................................................................................... 105
Prevent scan-quality problems .................................................................................... 105
Solve scan-quality problems ........................................................................................ 105
Clean the product .............................................................................................................................................. 106
Clean the pickup roller and separation pad .................................................................................... 106
Clean the paper path ....................................................................................................................... 112
Clean the toner-cartridge area ....................................................................................................... 113
Clean the exterior ............................................................................................................................ 116
Check the scanner glass for dirt and smudges ............................................................................... 117
Clean the pickup rollers and separation pad in the document feeder ........................................... 118
Solve performance problems ............................................................................................................................ 119
Solve connectivity problems ............................................................................................................................. 120
Solve direct-connect problems ...................................................................................................... 120
Solve wired network problems ....................................................................................................... 120
Poor physical connection ............................................................................................. 120
The computer is using the incorrect IP address for the product ................................. 120
The computer is unable to communicate with the product ........................................ 121
The product is using incorrect link and duplex settings for the network ................... 121
New software programs might be causing compatibility problems ........................... 121
The computer or workstation might be set up incorrectly .......................................... 121
The product is disabled, or other network settings are incorrect ............................... 121
Solve wireless network problems .................................................................................................. 122
Wireless connectivity checklist .................................................................................... 122
The product does not print after the wireless configuration completes .................... 123
The product does not print, and the computer has a third-party firewall installed ... 123
The wireless connection does not work after moving the wireless router or
product .......................................................................................................................... 123
Cannot connect more computers to the wireless product .......................................... 123
The wireless product loses communication when connected to a VPN ...................... 123
The network does not appear in the wireless networks list ....................................... 123
The wireless network is not functioning ...................................................................... 124
Perform a wireless network diagnostic test ................................................................ 124
Reduce interference on a wireless network ................................................................ 124
Service mode functions ..................................................................................................................................... 126
Secondary service menu ................................................................................................................. 126
Open the secondary service menu ............................................................................... 126
Secondary service menu structure .............................................................................. 126
Product resets ................................................................................................................................. 128
viii ENWW
Restore factory settings ............................................................................................... 128
NVRAM initialization ..................................................................................................... 128
Solve fax problems ............................................................................................................................................ 129
Check the hardware setup .............................................................................................................. 129
Faxes are sending slowly ................................................................................................................ 130
Fax quality is poor ........................................................................................................................... 131
Fax cuts off or prints on two pages ................................................................................................ 132
Product updates ................................................................................................................................................ 133
Appendix A Service and support .................................................................................................................... 135
Hewlett-Packard limited warranty statement ................................................................................................. 136
HP's Premium Protection Warranty: LaserJet toner cartridge limited warranty statement ........................... 137
HP policy on non-HP supplies ........................................................................................................................... 138
HP anticounterfeit Web site .............................................................................................................................. 139
Data stored on the toner cartridge ................................................................................................................... 140
End User License Agreement ............................................................................................................................ 141
OpenSSL ............................................................................................................................................................. 143
Customer self-repair warranty service ............................................................................................................. 144
Customer support .............................................................................................................................................. 145
Appendix B Product specifications ................................................................................................................. 147
Physical specifications ...................................................................................................................................... 148
Power consumption, electrical specifications, and acoustic emissions .......................................................... 148
Environmental specifications ............................................................................................................................ 148
Appendix C Regulatory information ............................................................................................................... 149
FCC regulations .................................................................................................................................................. 150
Environmental product stewardship program ................................................................................................. 151
Protecting the environment ........................................................................................................... 151
Ozone production ............................................................................................................................ 151
Power consumption ........................................................................................................................ 151
Toner consumption ......................................................................................................................... 151
Paper use ......................................................................................................................................... 151
Plastics ............................................................................................................................................ 151
HP LaserJet print supplies .............................................................................................................. 152
Return and recycling instructions ................................................................................................... 152
United States and Puerto Rico ...................................................................................... 152
Multiple returns (more than one cartridge) ............................................... 152
Single returns ............................................................................................. 152
Shipping ...................................................................................................... 152
ENWW ix
Non-U.S. returns ........................................................................................................... 153
Paper ............................................................................................................................................... 153
Material restrictions (LaserJet Pro MFP M125-M126 series) ......................................................... 153
Material restrictions (LaserJet Pro MFP M127-M128 series) ......................................................... 153
Disposal of waste equipment by users ........................................................................................... 154
Electronic hardware recycling ........................................................................................................ 154
Chemical substances ....................................................................................................................... 154
Material Safety Data Sheet (MSDS) ................................................................................................ 154
EPEAT .............................................................................................................................................. 154
For more information ...................................................................................................................... 154
Declaration of conformity (M125a-M125ra) .................................................................................................... 156
Declaration of conformity (M125nw-M126nw) ................................................................................................ 158
Declaration of conformity (M127fn-M128fn) ................................................................................................... 160
Declaration of conformity (M127fp-M128fp) ................................................................................................... 162
Declaration of conformity (M127fw-M128fw) ................................................................................................. 164
Safety statements ............................................................................................................................................. 166
Laser safety ..................................................................................................................................... 166
Canadian DOC regulations .............................................................................................................. 166
VCCI statement (Japan) ................................................................................................................... 166
Power cord instructions .................................................................................................................. 166
Power cord statement (Japan) ....................................................................................................... 166
EMC statement (Korea) ................................................................................................................... 167
Laser statement for Finland ........................................................................................................... 167
GS statement (Germany) ................................................................................................................ 168
Substances Table (China) ................................................................................................................ 168
SEPA Ecolabel User Information (China) ........................................................................................ 168
Restriction on Hazardous Substances statement (Turkey) ........................................................... 169
Restriction on Hazardous Substances statement (Ukraine) .......................................................... 169
Eurasian Conformity (Belarus, Kazakhstan, Russia) ...................................................................... 169
Additional statements for telecom (fax) products ........................................................................................... 170
EU Statement for Telecom Operation ............................................................................................ 170
New Zealand Telecom Statements ................................................................................................. 170
Additional FCC statement for telecom products (US) .................................................................... 170
Telephone Consumer Protection Act (US) ...................................................................................... 171
Industry Canada CS-03 requirements ............................................................................................ 171
Vietnam Telecom wired/wireless marking for ICTQC Type approved products ............................ 172
Additional statements for wireless products ................................................................................................... 173
FCC compliance statement—United States ................................................................................... 173
Australia statement ........................................................................................................................ 173
Brazil ANATEL statement ................................................................................................................ 173
Canadian statements ...................................................................................................................... 173
x ENWW
Products with 5 GHz Operation Industry of Canada ....................................................................... 173
Exposure to Radio Frequency Radiation (Canada) ......................................................................... 173
European Union regulatory notice .................................................................................................. 174
Notice for use in France .................................................................................................................. 174
Notice for use in Russia ................................................................................................................... 174
Mexico statement ........................................................................................................................... 174
Taiwan statement ........................................................................................................................... 175
Korean statement ........................................................................................................................... 175
Vietnam Telecom wired/wireless marking for ICTQC Type approved products ............................ 172
Index ........................................................................................................................................................... 177
ENWW xi
xii ENWW
List of tables
Table 1-1 Sequence of operation ......................................................................................................................................... 3
Table 1-2 Motors ................................................................................................................................................................... 7
Table 1-3 Solenoids .............................................................................................................................................................. 8
Table 1-4 Switches ............................................................................................................................................................... 8
Table 1-5 Sensors ................................................................................................................................................................. 9
Table 1-6 DC controller controlled components ............................................................................................................... 10
Table 1-7 DC power supply specifications ......................................................................................................................... 16
Table 1-8 Photo sensors, motor, and solenoid .................................................................................................................. 29
Table 1-9 Document feeder sensors .................................................................................................................................. 33
Table 2-1 Basic problem solving ........................................................................................................................................ 40
Table 2-2 HP Web Services menu (touchscreen control panel) ........................................................................................ 58
Table 2-3 Reports menu (touchscreen control panel) ....................................................................................................... 59
Table 2-4 Self Diagnostics menu (touchscreen control panel) ......................................................................................... 59
Table 2-5 Fax Setup menu (touchscreen control panel) ................................................................................................... 59
Table 2-6 System Setup menu (touchscreen control panel) ............................................................................................. 62
Table 2-7 Service menu (touchscreen control panel) ........................................................................................................ 64
Table 2-8 Network Setup menu (touchscreen control panel) ........................................................................................... 65
Table 2-9 Fax Menu (touchscreen control panel) .............................................................................................................. 65
Table 2-10 Copy Menu (touchscreen control panel) .......................................................................................................... 67
Table 2-11 HP Web Services menu (LCD control panel) .................................................................................................... 69
Table 2-12 PhoneBook Number menu (LCD control panel) ............................................................................................... 69
Table 2-13 Fax Functions menu (LCD control panel) ......................................................................................................... 70
Table 2-14 Reports menu (LCD control panel) .................................................................................................................. 70
Table 2-15 Fax Setup menu (LCD control panel) ............................................................................................................... 71
Table 2-16 System Setup menu (LCD control panel) ......................................................................................................... 74
Table 2-17 Service menu (LCD control panel) .................................................................................................................... 76
Table 2-18 Network Setup menu (LCD control panel) ....................................................................................................... 76
Table 2-19 Copy menu (LCD control panel) ....................................................................................................................... 77
Table 2-20 Control-panel messages .................................................................................................................................. 79
Table 2-21 General print-quality issues .......................................................................................................................... 100
Table 2-22 Copy print-quality problems ......................................................................................................................... 104
Table 2-23 Scan-quality problems .................................................................................................................................. 105
ENWW xiii
Table 2-24 Secondary service menu ................................................................................................................................ 126
Table B-1 Physical specifications ..................................................................................................................................... 148
Table B-2 Product dimensions with input tray opened ................................................................................................... 148
Table B-3 Operating-environment specifications ........................................................................................................... 148
xiv ENWW
List of figures
Figure 1-1 Product block diagram ........................................................................................................................................ 2
Figure 1-2 Engine-control system ........................................................................................................................................ 6
Figure 1-3 Motors ................................................................................................................................................................. 7
Figure 1-4 Solenoids ............................................................................................................................................................. 8
Figure 1-5 Switches .............................................................................................................................................................. 8
Figure 1-6 Sensors ................................................................................................................................................................ 9
Figure 1-7 DC controller block diagram ............................................................................................................................. 10
Figure 1-8 Fuser control circuit .......................................................................................................................................... 11
Figure 1-9 Fuser-heater control circuit .............................................................................................................................. 13
Figure 1-10 Low-voltage power supply (LVPS) ................................................................................................................. 15
Figure 1-11 High-voltage power supply ............................................................................................................................ 18
Figure 1-12 Laser/scanner system .................................................................................................................................... 19
Figure 1-13 Electrophotographic process block diagram (1 of 2) ..................................................................................... 21
Figure 1-14 Electrophotographic process block diagram (2 of 2) ..................................................................................... 22
Figure 1-15 Image formation process ............................................................................................................................... 23
Figure 1-16 Primary charging ............................................................................................................................................ 24
Figure 1-17 Laser beam exposure ..................................................................................................................................... 24
Figure 1-18 Toner cartridge ............................................................................................................................................... 25
Figure 1-19 Transfer ........................................................................................................................................................... 26
Figure 1-20 Separation ....................................................................................................................................................... 26
Figure 1-21 Fusing .............................................................................................................................................................. 27
Figure 1-22 Drum cleaning ................................................................................................................................................. 27
Figure 1-23 Pickup, feed, and delivery system block diagram ......................................................................................... 28
Figure 1-24 Photo sensors, motor, and solenoid .............................................................................................................. 29
Figure 1-25 Document feeder paper path and document feeder sensors ........................................................................ 33
Figure 2-1 Engine controller PCA connectors .................................................................................................................... 47
Figure 2-2 Main PCAs .......................................................................................................................................................... 48
Figure 2-3 Motor ................................................................................................................................................................. 49
Figure 2-4 Solenoid ............................................................................................................................................................ 50
Figure 2-5 Sensors .............................................................................................................................................................. 51
Figure 2-6 Cross section view ............................................................................................................................................. 52
Figure 2-7 General timing diagram .................................................................................................................................... 53
ENWW xv
Figure 2-8 Circuit diagram .................................................................................................................................................. 54
xvi ENWW
1 Theory of operation
●
Basic operation
●
Formatter-control system
●
Engine-control system
●
Image-formation system
●
Pickup, feed, and delivery system
●
Scanner system
●
Document feeder functions and operation
●
Fax functions and operation
ENWW 1
Basic operation
Major product systems
The product contains the following major systems:
●
Engine-control system
●
Laser/scanner system
●
Image-formation system
●
Pickup-and-feed system
●
Document feeder system (not shown)
Product block diagram
Figure 1-1 Product block diagram
LASER/SCANNER SYSTEM
ENGINE CONTROL
SYSTEM
IMAGE-FORMATION SYSTEM
PICKUP-AND-FEED SYSTEM
2 Chapter 1 Theory of operation ENWW
Sequence of operation
The DC controller in the engine-control system controls the operational sequences of the product. The table
below describes durations and operations for each period of a print operation from when the product is
turned on until the motor stops rotating.
NOTE: This sequence of operations is for the product base and does not include the document feeder.
Normal sequence of operation
Table 1-1 Sequence of operation
Name Timing Purpose
WAIT From the time the power switch is turned on, the door is
closed or the product exits Sleep mode until the product
gets ready for a print operation.
STBY (standby) From the end of the WAIT or LSTR period until either a
INTR (initial
rotation)
PRINT From the end of the INTR period until the last sheet
LSTR (last
rotation)
print command is sent or the power switch is turned off.
From the time a print command is received until the
paper is picked up.
completes the fuser operation.
From the end of the PRINT period until the main motor
stops rotating.
Brings the product to ready state. The product
performs the following during the operations:
●
Detects the toner cartridge
●
Heats the fuser film in the fuser
●
Rotates, and the stops, the main motor
Maintains the product in printable condition. The
product performs the following during the operation:
The product performs the following during the
operations:
●
Drives the main motor
●
Activates the high-voltage power supply
●
Activates the laser/scanner
●
Warms the fuser heater
Forms the image on the photosensitive drum based on
the VIDEO signals from the formatter. Transfers and
fuses the toner image to the paper.
Moves the last printed sheet out of the product. The
product performs the following during the operations:
●
Stops the main motor
●
Deactivates the high-voltage power supply
●
Deactivates the laser/scanner
●
Deactivates the fuser heater
The product enters the INTR period as the LSTR period
is completed, if the formatter sends another print
command.
ENWW Basic operation 3
Formatter-control system
The formatter is responsible for the following procedures:
●
Controlling sleep mode
●
Receiving and processing print data from the various product interfaces
●
Monitoring control-panel functions and relaying product-status information (through the control panel
and the network or bidirectional interface)
●
Developing and coordinating data placement and timing with the DC controller PCA
●
Storing font information
●
Communicating 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 imageformation system with the paper-input and -output systems, and then signals the formatter to send the
print-image data.
Sleep mode
After a user-specified time, the Sleep mode feature automatically conserves electricity by substantially
reducing power consumption when the product is not printing. After a user-specified time, the product
automatically reduces its power consumption (Sleep mode). The product returns to the ready state when a
button is pressed, a print job is received, or a door is opened. When the product is in Sleep mode, all of the
control-panel LEDs and the power button backlight LED is blinking or on.
NOTE: Although the product lights are off in Sleep mode, the product functions normally when it receives a
print job.
Input/output
The product receives print data primarily from the following:
●
Hi-Speed USB 2.0 port
●
10/100 Base-T network port.
●
Fax
●
Wireless
CPU
The formatter incorporates a 600 MHz processor.
Memory
The random access memory (RAM) on the formatter PCA contains the page and the I/O buffers. RAM stores
printing information received from the host system, and can also serve to temporarily store a full page of
print-image data before the data is sent to the print engine.
4 Chapter 1 Theory of operation ENWW
Firmware
●
The product has 128 MB of Synchronous DRAM, which is used for run-time firmware imaging and print,
fax, scan and copy job information during printing.
PJL overview
The printer job language (PJL) is an integral part of configuration, in addition to the standard printer
command language (PCL). With standard cabling, the product can use PJL to perform a variety of functions
such as these:
●
Two-way communication with the host computer through a network connection or a USB connection.
The product can inform the host about such things as the control-panel settings, and the control-panel
settings can be changed from the host.
●
Dynamic I/O switching. The product uses this switching to be configured with a host on each I/O. The
product can receive data from more than one I/O simultaneously, until the I/O buffer is full. This can
occur even when the product is offline.
●
Context-sensitive switching. The product can automatically recognize the personality (PS or PCL) of
each job and configure 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 product in landscape mode, the subsequent print jobs print in landscape mode only if they are
formatted for landscape printing.
LEDM overview
The low-end data model (LEDM) provides one consistent data representation method and defines the
dynamic and capabilities tickets shared between clients and devices, as well as the access protocol, event,
security, and discovery methods.
ACL overview
The advanced control language (ACL) is a language that supports product control and firmware downloads in
printers that support both PJL/PCL and host-based printing. Each sequence of ACL commands must be
preceded by a unified exit command (UEL) and an @PJL ENTER LANGUAGE=ACL command. The ACL sequence
is always followed by a UEL. Any number of commands can be placed between the UELs. The only exception
to these rules is the download command. If a firmware download is done, the download command must be
the last command in the sequence. It will not be followed by a UEL.
The firmware searches for the UEL sequence when parsing commands. However, while downloading binary
data such as host-based code or NVRAM data the firmware suspends UEL parsing. To handle hosts that
“disappear” during binary sequences, the firmware times out all ACL command sessions. If a timeout occurs
during a non-download command sequence, it is treated as the receipt of a UEL. If a timeout occurs during
firmware download the product resets.
Control panel
The formatter sends and receives product status and command data to and from the control-panel PCA.
ENWW Formatter-control system 5
Engine-control system
The engine-control system coordinates all product functions, according to commands that the formatter
sends. The engine-control system drives the laser/scanner system, the image-formation system, and the
pickup/feed/delivery system.
The engine control system contains the following major components:
●
Engine-control unit (ECU)
◦
DC controller
◦
Low-voltage power supply
●
High-voltage power supply
●
Fuser control
Figure 1-2 Engine-control system
ENGINE CONTROL SYSTEM
DC controller
LASER/SCANNER SYSTEM
Formatter
Low-voltage power supply
IMAGE-FORMATION SYSTEM
High-voltage power supply
MEDIA-FEED SYSTEM
Fuser control
6 Chapter 1 Theory of operation ENWW
Motors, solenoids, switches, and sensors
Figure 1-3 Motors
Table 1-2 Motors
Item Description Components driven
1
M1 Main motor
●
Pickup roller
●
Feed roller
●
Photosensitive drum
●
Developing roller
●
Pressure roller
●
Delivery roller
ENWW Engine-control system 7
Figure 1-4 Solenoids
1
Table 1-3 Solenoids
Item Description
SL1 Pickup solenoid
Figure 1-5 Switches
Table 1-4 Switches
Item Description
SW501 Cartridge-door switch
SW1100 Power switch; not shown (the power switch is part of the control-
panel assembly)
8 Chapter 1 Theory of operation ENWW
Figure 1-6 Sensors
4
3
2
Table 1-5 Sensors
Item Sensor Description
1 PS901 Main-motor rotation-number sensor; not shown
2 PS751 Top-of-Page (TOP) sensor
1
3 PS701 Fuser delivery sensor
4 PS702 Paper-width sensor
ENWW Engine-control system 9
DC controller operations
The DC controller controls the operational sequences of the product systems.
Figure 1-7 DC controller block diagram
AC input
Engine controller
Fuser unit
Transfer roller
Cartridge
Formatter
Low-voltage
power supply
High-voltage
power supply
Motor
Solenoid
Photointerrupter
DC controller
Switch
Laser scanner
Operation panel
Table 1-6 DC controller controlled components
Component Designator Description
Motor M1 Main motor
Solenoid SL1 Pickup solenoid
Photointerrupter PS701 Fuser delivery sensor
PS702 Media-width sensor
PS751 Top-of-Page (TOP) sensor
PS901 Main-motor rotation-number sensor
Switch SW501 Cartridge-door switch
SW1100 Power switch
10 Chapter 1 Theory of operation ENWW
Fuser-control circuit
The fuser-control circuit monitors and controls the temperature in the fuser. The product uses on-demand
fusing. The fuser-control circuit consists of the following major components:
●
Fuser heater (H1); heats the fusing film
●
Thermistor (TH1); detects the fuser temperature (contact type)
●
Thermoswitch (TP1); prevents abnormal temperature rise in the fuser (contact type)
Figure 1-8 Fuser control circuit
Fuser film
TH1
TP1
H1
FUSER HEATER CONTROL signal
Fuser heater control
circuit
Fuser control
Pressure roller
FUSER TEMPERATURE signal
Fuser heater safety
circuit
DC controller
Engine controller
ENWW Engine-control system 11
Fuser failure detection
The DC controller determines a fuser unit failure, releases the relay to interrupt power supply to the fuser
heater, and notifies the formatter of a failure state when it encounters the following conditions:
●
Start up failure
◦
If the main thermistor does not detect a specified temperature during the start up process of the
heater in the wait period.
◦
If the main thermistor does not detect a specified temperature during the heater temperature
control in the initial rotation period.
●
Abnormal low temperature
◦
If the main thermistor detects an abnormal low temperature of the fuser unit during the printing
operation.
●
Abnormal high temperature
◦
If the main thermistor detects an abnormal high temperature of the fuser unit.
●
Frequency detection circuit failure
◦
If a specified frequency of the FREQUENCY signal is not detected within a specified period after the
product is turned on.
12 Chapter 1 Theory of operation ENWW
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