Oki OKIPAGE18 User manual

40931201TH Rev. 4 1 / 244
OKIPAGE18 / OKIPAGE20Plus
LED Page Printer
Maintenance Manual
ODA/ OEL/ INT
2002-09-06 Rev. 4

40931201TH Rev. 4 2 /
PREFACE
This maintenance manual describes the field maintenance methods for OKIPAGE18/OKIPAGE20Plus.
This manual is written for use by maintenance personnel. Note, however, that the user should refer to
the USER’S MANUAL for methods of handling and operating the equipment.

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CONTENTS
1. CONFIGURATION....................................................................................... 7
1.1 System Configuration................................................................................................. 7
1.2 Printer Configuration .................................................................................................. 8
1.3 Optional Configuration ............................................................................................... 9
1.4 Specification............................................................................................................... 11
1.5 Safety Standards ....................................................................................................... 13
1.5.1 Certification label .......................................................................................... 13
1.5.2 Warning label................................................................................................ 13
2. OPERATION DESCRIPTION ...................................................................... 14
2.1 Main Control Board (BOARD-FFH)............................................................................ 16
2.2 Power Supply Unit ..................................................................................................... 20
2.3 Electro-photographic Process.................................................................................... 22
2.3.1 Electro-photographic process mechanism ................................................... 22
2.3.2 Electro-photographic process....................................................................... 24
2.3.3 Process operation descriptions .................................................................... 28
2.3.4 Revision of LED Head Illumination............................................................... 38
2.4 Paper Jam Detection ................................................................................................. 46
2.5 Cover Open................................................................................................................ 47
2.6 Toner Low Detection.................................................................................................. 48
2.7 Stacker-full Detection................................................................................................. 50
2.8 Page Size Detection .................................................................................................. 50
3. PARTS REPLACEMENT............................................................................. 51
3.1 Precautions for Parts Replacement ........................................................................... 51
3.2 Parts Layout............................................................................................................... 53
3.3 How to Change Parts................................................................................................. 56
3.3.1 Face -up Stacker Assy ................................................................................. 57
3.3.2 Contact Assy ................................................................................................ 58
3.3.3 DC Fan Motor............................................................................................... 59
3.3.4 OP Panel Assy ............................................................................................. 60
3.3.5 Board-FFH.................................................................................................... 61
3.3.6 Stacker Assy, Damper Arm, Cover Rear..................................................... 62
3.3.7 Sensor Stacker Full ...................................................................................... 63
3.3.8 Cable cover (guide film)................................................................................ 64
3.3.9 Damper......................................................................................................... 65
3.3.10 Feeder Unit-Front ......................................................................................... 66
3.3.11 Roller Assy-Regist....................................................................................... 67
3.3.12 Motor -Main .................................................................................................. 68
3.3.13 Guide Assy-Eject .......................................................................................... 70
3.3.14 Heat Assy ..................................................................................................... 71
3.3.15 Roller feed (C) ............................................................................................. 72
3.3.16 Roller Assy-BK ............................................................................................. 73
3.3.17 Roller Assy-Feed .......................................................................................... 74
3.3.18 LED Head..................................................................................................... 75
3.3.19 Paper cassette, ROLLER Ass-Feed, ROLLER-Assy-Hoppibg..................... 76
3.3.20 Frame Assy-Separation................................................................................ 77
3.3.21 Transfer Roller/TR Gear/TR Bearing............................................................ 78
3.3.22 EP lock shaft................................................................................................. 79
3.3.23 LEVER Assy- Out Sensor............................................................................. 80
3.3.24 Toner sensor lever........................................................................................ 81
3.3.25 Paper sensor lever ....................................................................................... 82
3.3.26 Inlet sensor lever .......................................................................................... 83
3.3.27 Power supply unit ......................................................................................... 84

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3.3.28 Lever-Paper end & Lever-Paper near end ................................................... 85
3.3.29 Guide Assy-Cassette (L) .............................................................................. 87
3.3.30 Guide Assy-Cassette (R).............................................................................. 88
4. ADJUSTMENT............................................................................................. 90
4.1 Maintenance Modes And Functions........................................................................... 90
4.1.1 User maintenance mode .............................................................................. 92
4.1.2 System maintenance mode.......................................................................... 96
4.1.3 Engine maintenance mode........................................................................... 98
4.1.4 EEPROM initialization .................................................................................. 102
4.2 Adjustment When Replacing A Part........................................................................... 103
4.2.1 Resetting the fuser counter .......................................................................... 104
4.2.2 Destination setting ........................................................................................ 105
4.2.3 Setting of LED head drive time..................................................................... 106
5. PERIODIC MAINTENANCE ........................................................................ 109
5.1 Periodic Replacing Part ............................................................................................. 109
5.2 Cleaning..................................................................................................................... 109
5.2.1 Cleaning of LED lens array........................................................................... 109
5.2.2 Cleaning the Plastic Film .............................................................................. 110
6. TROUBLESHOOTING PROCEDURES ...................................................... 111
6.1 Troubleshooting Tips ................................................................................................. 111
6.2 Points to Check before Correcting Image Problems.................................................. 111
6.3 Tips for Correcting Image Problems .......................................................................... 111
6.4 Preparation for Troubleshooting ................................................................................ 112
6.5 Troubleshooting Flow................................................................................................. 112
6.5.1 LCD status message/trouble list................................................................... 112
6.5.2 LCD message troubleshooting ..................................................................... 124
6.5.3 Image troubleshooting.................................................................................. 142
7. WIRING DIAGRAM..................................................................................... 153
7.1 Interconnect Signal Diagram...................................................................................... 153
7.2 PCB Layout................................................................................................................ 154
7.3 Resistance Check ...................................................................................................... 157
7.4 Program/Font ROM Location ..................................................................................... 159
8. PARTS LIST ................................................................................................ 160

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Appendix A CENTRONICS PARALLEL INTERFACE..................................... 168
Appendix B RS-232C SERIAL INTERFACE.................................................... 172
Appendix C Duplex Unit maintenance ........................................................... 174
1. OUTLINE ................................................................................................................... 174
1.1 Functions ...................................................................................................... 174
1.2 External View and Component Names......................................................... 174
2. MECHANISM DESCRIPTION ................................................................................... 175
2.1 General Mechanicsm.................................................................................... 175
2.2 JAM Release Mechanism............................................................................. 176
2.3 Removing/Installing Duplex Unit................................................................... 177
3. PARTS REPLACEMENT ........................................................................................... 179
3.1 Precautions Concerning Parts Replacement................................................ 179
3.2 Parts Layout ................................................................................................. 181
3.3 Parts Replacement Methods ........................................................................ 182
3.3.1 Board-LEX....................................................................................... 183
3.3.2 Connector (IMSA-9714N-14A) ........................................................ 184
3.3.3 Photo Sensor .................................................................................. 185
3.3.4 SOLENOID Assy............................................................................. 186
3.3.5 Motor ............................................................................................... 187
4. TROUBLESHOOTING............................................................................................... 188
4.1 Precautions Prior to the Troubleshooting ..................................................... 188
4.2 Preparations for the Troubleshooting ........................................................... 188
4.3 Troubleshooting Method............................................................................... 189
4.3.1 LCD Status Message List................................................................ 189
4.3.2 Troubleshooting Flow...................................................................... 190
5. CONNECTION DIAGRAM ......................................................................................... 193
5.1 Interconnection Diagram .............................................................................. 193
5.2 PCB Layout .................................................................................................. 194
6. PARTS LIST .............................................................................................................. 195
Appendix D Second/ Third Paper Feeder Maintenance................................ 198
1. OUTLINE ................................................................................................................... 198
1.1 Functions ...................................................................................................... 198
1.2 Appearance and Parts Name ....................................................................... 198
2. Description of operartion............................................................................................ 199
2.1 Driving Mechanism....................................................................................... 199
2.2 Hopper Mechanism ...................................................................................... 201
3. PARTS REPLACEMENT ........................................................................................... 202
3.1 Precautions Concerning Parts Replacement................................................ 202
3.2 Parts Layout ................................................................................................. 204
3.3 Parts Replacement Methods ........................................................................ 205
3.3.1 Roller assy hopping, Roller assy feed............................................. 206
3.3.2 Cover front assy .............................................................................. 207
3.3.3 Board-BBB ...................................................................................... 208
3.3.4 Lever paper end, Lever paper near end.......................................... 209
3.3.5 Motor ............................................................................................... 210
3.3.6 Connector (IMSA-9714N-14B), Connector (IMSA-9714N-14A)...... 211
3.3.7 Frange pulley, pulley Idle, Mini pitch belt, Plate Earth shaft,
Gear double, Tray switch assy........................................................ 212
3.3.8 Roller feed .................................................................................................... 213
3.3.9 Bracket sub roller.......................................................................................... 214
3.3.10 Frame side (L) assy...................................................................................... 215
3.3.11 Frame side (R) assy ..................................................................................... 216

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4. TROUBLESHOOTING............................................................................................... 217
4.1 Precautions Prior to the Troubleshooting ..................................................... 217
4.2 Preparations for the Troubleshooting ........................................................... 217
4.3 Troubleshooting Method............................................................................... 218
4.3.1 LCD Status Message List................................................................ 218
4.3.2 Troubleshooting Flow...................................................................... 219
5. CONNECTION DIAGRAM ......................................................................................... 220
5.1 Interconnection Diagram .............................................................................. 220
5.2 PCB Layout .................................................................................................. 221
6. PARTS LIST .............................................................................................................. 222
Appendix E Multi Feeder Maintenance .......................................................... 225
1. OUTLINE ................................................................................................................... 225
1.1 Functions ...................................................................................................... 225
1.2 External View and Component Names......................................................... 225
2. MECHANISM DESCRIPTION ................................................................................... 226
2.1 General Mechanism ..................................................................................... 226
2.2 Hopper Mechanism ...................................................................................... 226
3. PARTS REPLACEMENT ........................................................................................... 227
3.1 Precautions Concerning Parts Replacement................................................ 227
3.2 Parts Layout ................................................................................................. 229
3.3 Parts Replacement Methods ........................................................................ 230
3.3.1 Separator ........................................................................................ 231
3.3.2 AOLE-PCB ...................................................................................... 232
3.3.3 Square-shaped connector............................................................... 233
3.3.4 Hopping Motor................................................................................. 234
3.3.5 Planet gear...................................................................................... 235
3.3.6 Roller B ........................................................................................... 236
3.3.7 Roller A ........................................................................................... 237
3.3.8 Mini pitch belt & Feed roller............................................................. 238
4. TROUBLESHOOTING............................................................................................... 239
4.1 Precautions Prior to the Troubleshooting ..................................................... 239
4.2 Preparations for the Troubleshooting ........................................................... 239
4.3 Troubleshooting Method............................................................................... 239
4.3.1 LCD Status Message List................................................................ 240
4.3.2 Troubleshooting Flow...................................................................... 241
5. CONNECTION DIAGRAM ......................................................................................... 242
5.1 Interconnection Diagram .............................................................................. 242
5.2 PCB Layout .................................................................................................. 242
6. PARTS LIST .............................................................................................................. 243

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1. CONFIGURATION
1.1 System Configuration
OKIPAGE18 / OKIPAGE20Plus consists of control and engine blocks as the standard configu-
ration (See Figure 1-1.)
In addition, the following options are also available.
Printer
Operator
panel
Face down
stacker
Face up
stacker
Power
supply
unit
DC Fan
Main control
PC etc.
Centronics
Parallel interface
(Bidirection)
OKI HSP
interface board
(Option)
LAN etc.
Extension D-RAM
SIMM
(Option)
4MB/ 8MB
Flash ROM SIMM
(Option)
: Paper feeding
: Singal flow
*: Consumables
: produced by third vender
High Capacity
Second Paper
Feeder
(Option)
High Capacity
Third Paper
Feeder
(Option)
Multi Feeder
(Option)
Duplex Unit
(Option)
Paper size
detection switch
Paper tray
LED head
Motor-Main
Hopping motor
Front Feeder
Printer
Mechanism
I/D unit
*
*
AC IN
120V
230V
Toner Cartridge
RS-232C
Serial I/F
Figure 1-1

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1.2 Printer Configuration
The printer unit consists of the following hardware components:
• Electro-photographic processor
• Paper feeder
• Controller
• Operator panel
• Power supply unit
Figure 1-2 shows the printer unit configuration.
Figure 1-2
Face-up stacker Assy
Cover-Rear
Cover-Frame
Heat Assy
Stacker Assy
Cover-Side(R)
I/D Unit
Manual Feed Assy
Base Unit
Cover-Side(L) Assy
Cover-Blind
Contact Assy
Frame-OP panel Assy Cover-Side(I/F)
Plate-Shield

40931201TH Rev. 4 9 /
1.3 Optional Configuration
The options below are available for use with OKIPAGE18 / OKIPAGE20Plus. They are sold
separately from the printer unit.
(1) Multi Feeder
(2) Second/ Third Paper Feeder
(3) DUPLEX Unit

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(4) D-RAM SIMM module (72 pin SIMM, 16 MB/32 MB, EDO SIMM type)
(5) Flash ROM module (72 pin SIMM, 4MB/8MB)
See 7.2 (1) for where
to install.
See 7.2 (1) for where
to install.

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1.4 Specification
(1) Type Desk top
(2) External dimensions Height 13.0”(331 mm)
(excludes protruding Width 14.4”(366 mm)
Portion) Depth 18.2”(462 mm)
(3) Weight 19.0 kg (42 lbs) If Installed Duplex 21.3 kg (47 lbs)
(4) Development method Dry electrophotography
Exposure method LED stationary head
(5) Paper used <Type>
•Standard paper
–Xerox 4200 (20 lbs)
•Application paper (manual face-up feed)
–Label
–Envelope
–OHP paper (Transparency)
<Size>
•Standard sizes
–Letter
–Legal
–Executive
–Envelope (without Duplex printing)
–A4
–A5 (without Duplex printing)
–B5 (without Duplex printing)
–A6 (without Duplex printing)
•Applicable sizes
–Width: 3.4”to 8.5”(86 to 216 mm)
–Length: 5.5”to 14”(140 to 355.6 mm)
<Thickness>
–Automatic feed: 16 to 28 lbs (60 to 105 g/m2)
–Manual feed: Label, OHP paper (transparency)
Envelope, 16~36 lb
(6) Printing speed First print: 7.4 sec.
Continuous print: 20 sheets/min.
[at duplex print :10 sheets/min]
Warm-up time: 90 sec. [at room temperature 77˚F
(25˚C) and rated voltage (120 VAC)]
(7) Paper feed method Automatic feed or manual feed
(8) Paper delivery method Face down/face up
(9) Resolution 600 x 600 dots/inch (default)
600 x 1200 dots/inch
(10)Power input 120 VAC + 5.5%, –15% (ODA)
230 VAC + 10%
(11)Power consumption Peak: Approx. 860W
Typical Operation: Approx. 400W
Idle: Approx. 95W
Power save mode: Approx. 25W

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(12)Temperature and humidity
(13) Noise During operation: 52 dBA or less (without second tray)
55 dBA or less (with second tray)
At standby: 45 dBA or less
Power save mode: 43 dBA or less
(14)Consumables Toner cartridge kit 6,000 pages(5% duty)*
Image drum cartridge 30,000 pages(at continuous Simplex printing)*
19,000 pages(3 page/job)(Simplex printing)*
* Simplex printing without Power Save.
Temperature 50 - 90 32 - 110 14 - 110 °F
In operation Power off mode During Storage Unit
Maximum wet
bulb temperature
Minimum difference
of wet and dry
bulb temperatures
Humidity
35.6 35.6 °F
77 80.4 °F
(10 - 32) (0 - 43) (–10 - 43) (°C)
20 - 80 10 - 90 10 - 90 %RH
(25) (26.8) (°C)
(2) (2) (°C)
Notes:
1. Storage conditions specified above apply to printers in packed condition.
2. Temperature and humidity must be in the range where no condensation
occurs.
10
28
32
Temperature
(°C)
20 80 Humidity (%)
Operation range

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1.5 Safety Standards
1.5.1 Certification label
The safety certification label is affixed to the printer in the position below.
ex. ODA 120V
1.5.2 Warning label
The warning label is affixed to the portion which may cause an injury to human body.
Follow the instructions on warning labels during maintenance.

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2. OPERATION DESCRIPTION
OKIPAGE18 / OKIPAGE20Plus consists of a main control board, a power supply unit (120V/
230V),apowersupplyunit(highvoltage),anoperatorpanelandanelectro-photographicprocess
mechanism.
The control board receives data through a host I/F, decodes and edits the data, and stores the
edited data in a memory. After completing edition of one page of data, it references the font
memoryandgenerates bitdataon the samememory. At the sametime,it transfersthebit image
data to an LED head in units of one dot line.
The electro-photographic process mechanism prints data on paper.
The operator panel is used for operations and status display.
Fig. 2-1 shows an OKIPAGE18 / OKIPAGE20Plus block diagram.

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Figure 2-1 OKIPAGE18 / OKIPAGE20Plus block diagram
FLASH ROM
Module
PS ROM
Extension
DRAM
Module
DRAM
Centronics
I/F
RS232C
I/F
LAN etc.
(Option)
Outlet sensor
AC120V/230V
OKI
HSP I/F
Board
(Option)
PCL ROM
Driver
Receiver
Driver
Receiver
TRANSISTOR
TRANSISTOR
DRIVER
DRIVER
EEPROM
Operator panel
LED HEAD
THERMISTOR
CHARGE ROLLER
SUB CHARGE ROLLER
TRANFER ROLLER
DEVELOPPING ROLLER
TONER SUPPLY ROLLER
CLEANING ROLLER
HEATOR
DUPLEX unit
MULTI feeder
2nd tray
BOARD PXC
CL
CL
M
M
3rd tray
Paper end sensor
Paper near end sensor
Inlet sensor1
POWER
SUPPLY
UNIT
(AC120V/230V)
POWER
SUPPLY
UNIT
(high voltage)
Inlet sensor2
Toner sensor
paper sensor
Tray size
sensor board
Clutch for
Regist Roller
Clutch for
Hopping Roller
Hopping Motor
Main Motor
CPU
LSI
DRIVER
DRIVER
FILTER CIRCUIT
0V
LSI
MAIN BOARD (BOARD-FFH)
3V 5V +8V -8V 38V
HIGH
VOLTAGE
CIRCUIT
FAN
COVER
OPEN
SW
LOW VOLTAGE
GENERATION
CIRCUIT
Sub-CH
CH
TR
DB
SB
CB

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Built-in device Function
Chip select controller Control of peripheral LSI, ROM, DRAM and I/O device
Bus controller
DRAM controller
DMA controller Transfer of data from Host I/F to RAM
Serial interface controller Control of RS232C serial interface
Parallel interface controller Control of Centronics parallel interface
Timer Generation of various control timing
Monitoring of paper running and paper size
Serial I/O port Control of serial interface between controller and operator panel, EEPROM
Control of a serial interface between controller and power supply board
I/O port Inputting of various sensor signals
Outputting of various control signals
Motor driver controller Control of Main Motor
Image processing circuit Executes the image data process for printing.
2.1 Main Control Board (BOARD-FFH)
ThecontrolboardconsistsofanonechipCPU,aLSI,program/fontROM's,DRAM's,anEEPROM,
a host interface circuit, and a mechanism driving circuit.
(1) One-chip CPU
Theone-chip CPUis acustom CPU(32-bit internalbus, 32-bitexternal bus,140-MHzclock)
that incorporates an RISC CPU and its peripheral devices, and has the following functions.
(2) Program/font ROM's
• PCL ROM
Theprogram/font ROM'sstoretheHPLJ5 emulationprogram andvarioustypesoffont.
MASK ROM is used as the program/font ROM's.
• PS ROM
The program/font ROM's store the Adobe PostScript Level 2 program and its fonts.

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Memory area Use Memory capacity setting
MENU Expansion RAM
System area Fixed Fixed
Raster buffer Enable Expandable
Receive buffer Enable Expandable
Page buffer – Expandable
DLL/macro buffer – Expandable
Font cache buffer Enable Expandable
(3) DRAM's
16-MegabyteDRAM (64Mbit DRAMx 2)is mountedas residentmemory tobe usedfor storing
the program and providing various buffers. This DRAM is expandable up to 128 Mbytes by
adding expansion memory (SIMMs). This DRAM provides the areas shown in the following
table.
(4) EEPROM
The EEPROM has a 16-kbit capacity and stores the following data.
• Menu data
• Various counter data (page counter, drum counter, fuser counter, etc.)
• Adjustment parameters (LED head drive time, print start position, etc.)
(5) LSI (LZ9FF22)
Built in device Function
Serial I/O port Control of serial interface between controller and 2nd tray, 3rd tray, Multi purpose feeder
Control of serial interface between controller and Duplex unit
Motor driver controller Control of Hopping motor
I/O port Inputting of various sensor signals
Outputting of various control signals
(6) Host interface
This printer has the following interfaces to the host.
• Centronics bidirectional parallel interface
• RS232C interface
• OKI HSP interface (Option)
The single effective interface or the automatic interface select mode can be selected using
themenu. Ifthebusy state of theprintercontinuesfor a long timeperiod,thebuffer near-full
control releases the busy status at constant intervals even if the host side is busy so not to
cause the interface time-out at the host side.
Working area used for the program
Stores converted bit image data
Stores temporarily the data received
from the host interface
Adds print information to the analyzed
receive data and stores the resulted
data.
Stores soft fonts and macro data.
Stores bit map fonts generated by the
font rasterizer based on scalable font
information

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(a) Centronics bidirectional parallel interface
This is an interface conforming to IEEE-1284 and provides either of unidirectional and
bidirectionalcommunicationsaccordingtoeachofthefollowingcommunicationmodes.
• Compatibility mode
Unidirectional communications from the host to the printer.
• Nibble mode
This mode transmits 4-bit wide data from the printer to the host. In this mode, each
1-byte data is transferred in the form of two nibbles using ERROR, BUSY, FAULT,
and SELECT signal leads. This mode can provide the bidirectional operation in
combination with the compatibility mode.
• ECP mode
This mode provides the asynchronous bidirectional interface and transmits and
receives 1-byte data using eight data signal leads under the semi-duplex control by
the host.
When the power is turned on, the compatibility mode is automatically selected. The
change to another mode from the compatibility mode is made through negotiation.
(WhentheBIDIRECTIONissettoENABLEinthemenu,thischangecanbeperformed.)
(For the electrical/physical characteristics of this interface, see APPENDIX B)
(b) RS232C serial interface
The following protocol is supported for the serial interface conforming to EIA RS232C.
• READY/BUSY (DTR HI or DTR LO)
• X-ON/X-OFF
• RBST X-ON
(For the electrical/ physical characteristics of the interface, see APPENDIX B)
(c) OKI HSP interface (Option)
This interface (slot) is an OKI unique universal interface that provides the platform to
connect various of boards (including those supplied by third venders) such as the LAN
connection expansion board and SCSI expansion board.
Any expansion boards compatible with this interface can be mounted on the Control
boardinthepiggybackboardfromwithoutmodifyingtheprogramattheprinterside. The
conceptual diagram of the OKI HSP interface is shown in Figure 2-2.
(For the electrical/physical characteristics of the OKI HSP interface, see the OKI HSP
interface technical manual.)
Printer
Control board LAN
expansion board
OKI HSP
interface
Network, etc.
Figure 2-2

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(7) RAM module
• Pin layout
• Basic specificaton
- Type: 72 pins Standerd SIMM (32 bits buss width)
[Note : EDO SIMMtype]
- Access time: 60ns, 70ns, 80ns, 100ns
- Capacity: 16 or 32MB
- Parity: None
(8) Flash ROM module
• Pin layout
• Basic specificaton
- Type: 72 pins SIIM (32 bits buss width)
- Access time: 90ns
- Capacity: 4 or 8MB
Board-FSL or Board-FSL-2
1363772
1363772
(4MB) (8MB)

40931201TH Rev. 4 20 /
Output voltage Use
+5 V Logic circuit supply voltage
+30 V Motor and fan drive voltage and source voltage for high-voltage supply
+8 V Reset circuit, RS232C Line voltage
–8 V RS232C Line voltage
+3.8V LED HEAD supply voltage
Output Voltage Use Remarks
Sub-CH -15 µ A Voltage applied to Sub charging roller
CH -1.30 KV Voltage applied to charging roller
DB -220 V/+300 V Voltage applied to developing roller
SB -450 V Voltage applied to toner supply roller
TR +4 KV/-1.3 kV Voltage applied to transfer roller Variable + Only
CB +450 V/-1350V Voltage applied to clearimng roller
2.2 Power Supply Unit
The power supply unit consists of an AC filter circuit, a low voltage power supply circuit, a high
voltage power supply circuit, heater drive circuit, and photosensors.
(1) Low voltage power supply circuit
This circuit generates the following voltages.
(2) High voltage power supply circuit
This circuit generates the following voltages necessary for electro-photographic processing
from+30Vaccordingtothecontrolsequencefromthecontrolboard. Whencoveropenstate
isdetected,+30Vsupplyisautomaticallyinterruptedtostopthesupplyofallthehigh-voltage
outputs.
(3) Photosensor
The photosensor mounted on this power supply unit supervises the paper running state
during printing.