Okidata OKIPAGE 20, OKIPAGE 20n Maintenance Manual

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OKIPAGE20 / OKIPAGE20n

LED Page Printer

Maintenance Manual

ODA/ OEL/ INT

All specifications are subject to change without notice.

PostScript, Adobe and the PostScript logo are trademarks of Adobe Systems Incorporated, registered
in the U.S.A.
*Times, Helvetica and Palatino are trademarks of Linotype AG and/or its subsidiaries.
ITC Avant Garde Gothic, ITC Zapf Chancery, ITC Zapf Dingbats and ITC Bookman are registered
trademarks of International Typeface Corporation.
HP and LaserJet are registered trademarks of Hewlett-Packard Company.
Diablo 630 is a registered trademark of Xerox corporation.
AppleTalk is a registered trademark of Apple Computer, Inc.
LocalTalk is a trademark of Apple Computer, Inc.

PREFACE

This maintenance manual describes the field maintenance methods for OKIPAGE20 / OKIPAGE20n.
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.

CONTENTS

1. CONFIGURATION....................................................................................... 1 - 1

1.1 System Configuration................................................................................................. 1 - 1

1.2 Printer Configuration .................................................................................................. 1 - 2

1.3 Optional Configuration ............................................................................................... 1 - 3

1.4 Specification............................................................................................................... 1 - 5

1.5 Safety Standards ....................................................................................................... 1 - 7

1.5.1 Certification label .......................................................................................... 1 - 7

1.5.2 Warning label................................................................................................ 1 - 7

2. OPERATION DESCRIPTION ...................................................................... 2 - 1

2.1 Main Control Board (BOARD-AAA) ........................................................................... 2 - 3

2.2 Power Supply Unit ..................................................................................................... 2 - 7

2.3 Electro-photographic Process.................................................................................... 2 - 9

2.3.1 Electro-photographic process mechanism ................................................... 2 - 9

2.3.2 Electro-photographic process....................................................................... 2 - 11

2.3.3 Process operation descriptions .................................................................... 2 - 15

2.3.4 Revision of LED Head Illumination............................................................... 2 - 25

2.4 Paper Jam Detection ................................................................................................. 2 - 30

2.5 Cover Open................................................................................................................ 2 - 31

2.6 Toner Low Detection.................................................................................................. 2 - 32

2.7 Stacker-full Detection................................................................................................. 2 - 34

2.8 Page Size Detection .................................................................................................. 2 - 34

2.9 PostScript ROM module (BOARD-MSM or BOARD-FSL)......................................... 2 - 34

3. PARTS REPLACEMENT............................................................................. 3 - 1

3.1 Precautions for Parts Replacement ........................................................................... 3 - 1

3.2 Parts Layout............................................................................................................... 3 - 3

3.3 How to Change Parts................................................................................................. 3 - 6

3.3.1 Face -up Stacker Assy ................................................................................. 3 - 7

3.3.2 Contact Assy ................................................................................................ 3 - 8

3.3.3 DC Fan Motor ............................................................................................... 3 - 9

3.3.4 OP Panel Assy ............................................................................................. 3 - 10

3.3.5 Board-AAA.................................................................................................... 3 - 11

3.3.6 Stacker Assy, Damper Arm, Cover Rear..................................................... 3 - 12

3.3.7 Sensor Stacker Full ...................................................................................... 3 - 13

3.3.8 Cable cover (guide film)................................................................................ 3 - 14

3.3.9 Damper......................................................................................................... 3 - 15

3.3.10 Feeder Unit-Front ......................................................................................... 3 - 16

3.3.11 Roller Assy-Regist ........................................................................................ 3 - 17

3.3.12 Motor -Main .................................................................................................. 3 - 18

3.3.13 Guide Assy-Eject .......................................................................................... 3 - 20

3.3.14 Heat Assy ..................................................................................................... 3 - 21

3.3.15 Roller feed (C) .............................................................................................. 3 - 22

3.3.16 Roller Assy-BK ............................................................................................. 3 - 23

3.3.17 Roller Assy-Feed .......................................................................................... 3 - 24

3.3.18 LED Head ..................................................................................................... 3 - 25

3.3.19 Paper cassette, ROLLER Ass-Feed, ROLLER-Assy-Hoppibg..................... 3 - 26

3.3.20 Frame Assy-Separation................................................................................ 3 - 27

3.3.21 Transfer Roller/TR Gear/TR Bearing............................................................ 3 - 28

3.3.22 EP lock shaft................................................................................................. 3 - 29

3.3.23 LEVER Assy- Out Sensor............................................................................. 3 - 30

3.3.24 Toner sensor lever........................................................................................ 3 - 31

3.3.25 Paper sensor lever ....................................................................................... 3 - 32

3.3.26 Inlet sensor lever .......................................................................................... 3 - 33

3.3.27 Power supply unit ......................................................................................... 3 - 34

3.3.28 Lever-Paper end & Lever-Paper near end ................................................... 3 - 35

3.3.29 Guide Assy-Cassette (L) .............................................................................. 3 - 37

3.3.30 Guide Assy-Cassette (R).............................................................................. 3 - 38

4. ADJUSTMENT............................................................................................. 4 - 1

4.1 Maintenance Modes And Functions........................................................................... 4 - 1

4.1.1 User maintenance mode .............................................................................. 4 - 3

4.1.2 System maintenance mode.......................................................................... 4 - 7

4.1.3 Engine maintenance mode........................................................................... 4 - 10

4.1.4 EEPROM initialization .................................................................................. 4 - 14

4.2 Adjustment When Replacing A Part........................................................................... 4 - 15

4.2.1 Resetting the fuser counter .......................................................................... 4 - 16

4.2.2 Destination setting........................................................................................ 4 - 17

5. PERIODIC MAINTENANCE ........................................................................ 5 - 1

5.1 Periodic Replacing Part ............................................................................................. 5 - 1

5.2 Cleaning..................................................................................................................... 5 - 1

5.2.1 Cleaning of LED lens array........................................................................... 5 - 1

5.2.2 Cleaning the Plastic Film .............................................................................. 5 - 2

6. TROUBLESHOOTING PROCEDURES ...................................................... 6 - 1

6.1 Troubleshooting Tips ................................................................................................. 6 - 1

6.2 Points to Check before Correcting Image Problems.................................................. 6 - 1

6.3 Tips for Correcting Image Problems .......................................................................... 6 1

6.4 Preparation for Troubleshooting ................................................................................ 6 - 2

6.5 Troubleshooting Flow................................................................................................. 6 - 2

6.5.1 LCD status message/trouble list................................................................... 6 - 2

6.5.2 LCD message troubleshooting ..................................................................... 6 - 14

6.5.3 Image troubleshooting.................................................................................. 6 - 34

7. WIRING DIAGRAM...................................................................................... 7 - 1

7.1 Interconnect Signal Diagram...................................................................................... 7 - 1

7.2 PCB Layout................................................................................................................ 7 - 2

7.3 Resistance Check ...................................................................................................... 7 - 5

7.4 Program/Font ROM Location ..................................................................................... 7 - 7

8. PARTS LIST ................................................................................................ 8 - 1

APPENDIX A CENTRONICS PARALLEL INTERFACE ................................ A - 1

APPENDIX B RS-232C SERIAL INTERFACE ............................................... B - 1

APPENDIX C DUPLEX UNIT.......................................................................... C - 1

APPENDIX D Second/ Third Paper Feeder.................................................. D - 1

APPENDIX E Multi Feeder ............................................................................ E - 1

1. CONFIGURATION

1. CONFIGURATION

1.1 System Configuration

OKIPAGE20 / OKIPAGE20n consists of control and engine blocks as the standard configura-

tion (See Figure 1-1.)

In addition, the following options are also available.

PC etc.

Centronics

Parallel interface

(Bidirection)

RS-232C

Serial I/F

Printer

Operator

panel

Main control

Power/
Sensor

Board

DC Fan

Face down

stacker

Printer

Mechanism

I/D unit

LED head
Motor-Main
Hopping motor

AC IN

120V
230V

Face up

stacker

*

*

Toner Cartridge

Front Feeder

LAN etc.

OKI HSP

interface board

(Option)

Extension D-RAM

SIMM

(Option)

4MB/ 8MB

Flash ROM SIMM

(Option)

: Paper feeding
: Singal flow

or

PostScript

SIMM

(Option)

Figure 1-1

1 - 1

Paper tray

Paper size

detection switch

High Capacity
Second Paper

Feeder

(Option)

High Capacity

Third Paper

Feeder

(Option)

*: Consumables

: produced by third vender

Multi Feeder

(Option)

Duplex Unit

(Option)

1.2 Printer Configuration

The printer unit consists of the following hardware components:

• Electro-photographic processor

• Paper feeder

• Controller

• Operator panel

• Power/sensor board
Figure 1-2 shows the printer unit configuration.

Stacker Assy

Frame-OP panel Assy

Plate-Shield

Cover-Side(I/F)

Face-up stacker Assy

Cover-Rear

Cover-Side(L) Assy

Contact Assy

Cover-Frame

Heat Assy

Cover-Side(R)

Manual Feed Assy

Base Unit

Figure 1-2

I/D Unit

1 - 2

1.3 Optional Configuration

The options below are available for use with OKIPAGE20 / OKIPAGE20n. They are sold

separately from the printer unit.

(1) Multi Feeder

(2) Second/ Third Paper Feeder

(3) DUPLEX Unit

1 - 3

(3) D-RAM SIMM module (72 pin SIMM, 4 MB/8 MB/16 MB/32 MB)

(4) Flash ROM module (72 pin SIMM, 4MB/8MB)

(5) PostScript ROM module (72pin SIMM)

1 - 4

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
–A4
–A5
–B5
–A6

• 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: 8 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

600 x 1200 dots/inch

(10)Power input 120 VAC + 5.5%, –15% (ODA)

230 VAC + 10%

1 - 5

(11) Power consumption Peak: Approx. 820W

Typical Operation: Approx. 350W
Idle: Approx. 95W
Power save mode: Approx. 25W

(12) Temperature and humidity

In operation Power off mode During Storage Unit

Temperature 50 - 90 32 - 110 14 - 110 °F

(10 - 32) (0 - 43) (–10 - 43) (°C)
Humidity
Maximum wet

bulb temperature
Minimum difference

of wet and dry
bulb temperatures

20 - 80 10 - 90 10 - 90 %RH

77 80.4 °F

(25) (26.8) (°C)

35.6 35.6 °F
(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.

Temperature

(°C)

32

28

Operation range

10

20 80

Humidity (%)

(13) Noise During operation: 50 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 5,000 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.

1 - 6

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.

1 - 7

2. OPERATION DESCRIPTION

2. OPERATION DESCRIPTION

OKIPAGE20 / OKIPAGE20n consists of a main control board, a power supply unit (120V/230V),
a power supply unit (high voltage), an operator panel and an electro-photographic process
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
memory and generates bit data on the same memory. At the same time, it transfers the bit 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 OKIPAGE20 / OKIPAGE20n block diagram.

2 - 1

FLASH ROM

Module

or

PS ROM

Module

MAIN BOARD (BOARD-AAA)

DUPLEX unit

MULTI feeder

Centronics

I/F

RS232C

I/F

LAN etc.

(Option)

ROM

Extension

DRAM

Module

DRAM

7407

75188

OKI

HSP I/F

Board

(Option)

3V 5V +8V -8V 38V

CPU

LSI

EEPROM

TRANSISTOR

TRANSISTOR

DRIVER

DRIVER

2nd tray

Paper end sensor

Paper near end sensor

BOARD PXC

Clutch for

CL

Regist Roller

Clutch for

CL

Hopping Roller

Hopping Motor

M

Main Motor

M

Operator panel

LED HEAD

3rd tray

Tray size
sensor board

POWER
SUPPLY
UNIT
(AC120V/230V)

Outlet sensor

FILTER CIRCUIT

AC120V/230V

LOW VOLTAGE

GENERATION

CIRCUIT

Inlet sensor1
paper sensor

Inlet sensor2
Toner sensor

LSI

COVER

OPEN

SW

DRIVER

DRIVER

POWER
SUPPLY
UNIT
(high voltage)

0V

HIGH

VOLTAGE

CIRCUIT

Sub-CH

CH

TR

DB

SB

CB

Figure 2-1 OKIPAGE20 / OKIPAGE20n block diagram

THERMISTOR

SUB CHARGE ROLLER

CHARGE ROLLER

TRANFER ROLLER

DEVELOPPING ROLLER

TONER SUPPLY ROLLER

CLEANING ROLLER

FAN

HEATOR

2 - 2

2.1 Main Control Board (BOARD-AAA)

The control board consists of an one chip CPU,a LSI, program/font ROM's, DRAM's, an
EEPROM, a host interface circuit, and a mechanism driving circuit.

(1) One-chip CPU

The one-chip CPU is a custom CPU (32-bit internal bus, 32-bit external bus, 40-MHz clock)
that incorporates an RISC CPU and its peripheral devices, and has the following functions.

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
Motr driver controller Control of Main Motor
Compression/extension circuit Compressed frame buffer is produced by compressing the data of temporary

band buffer.

Extension printing operation is executed by extending the data of

compressed frame buffer

(2) Program/font ROM's

The program/font ROM's store the HP LJ5 emulation program and various types of font.
MASK ROM is used as the program/font ROM's.

2 - 3

(3) DRAM's

4-Megabyte DRAM (16 Mbit DRAM x 2) is mounted as resident memory to be used for storing
the program and providing various buffers. This DRAM is expandable up to 68 Mbytes by
adding expansion memory (SIMMs). This DRAM provides the areas shown in the following
table.

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

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

(4) EEPROM

The EEPROM has a 1-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

the menu. If the busy state of the printer continues for a long time period, the buffer near­full 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.

2 - 4

(a) Centronics bidirectional parallel interface

This is an interface conforming to IEEE-1284 and provides either of unidirectional and
bidirectional communications according to each of the following communication modes.

• 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.
(When the BI DIRECTION is set to ENABLE in the menu, this change can be performed.)
(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
board in the piggyback board from without modifying the program at the printer side. The

conceptual diagram of the OKI HSP interface is shown in Fig. 2-2.
(For the electrical/physical characteristics of the OKI HSP interface, see the OKI HSP
interface technical manual.)

Printer

Network, etc.

Control board

LAN

expansion board

OKI HSP

interface

Fig. 2-2

2 - 5

(7) RAM module

• Pin layout

1363772

• Basic specificaton

- Type: 72 pins Standerd SIMM (32 bits buss width)

- Access time: 60ns, 70ns, 80ns, 100ns

- Capacity: 4, 8, 16 or 32MB

- Parity: None

(8) Flash ROM module

• Pin layout

Board-FSL

[Note : EDO SIMMtype cannot be used.]

1363772

• Basic specificaton

- Type: 72 pins SIIM (32 bits buss width)

- Access time: 90ns

- Capacity: 4 or 8MB

(9) PS ROM module

PS ROM module is BOARD-MSM or BOARD-FSL
BOARD MSM consists of MASK ROM

BOARD FSL consists of Flash ROM (8MB).

• Pin layout

BOARD-MSM

or

BOARD-FSL

1363772

• Basic specificaton

- Type:72 pins SIIM (32 bits buss width)

- Access time: 100ns (Board-MSM), 90n (Board-FSL)

- Capacity: 6MB (Board-MSM), 8MB (Board-FSL)

• Emulation : Pstscript Level 2

2 - 6

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.

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

(2) High voltage power supply circuit

This circuit generates the following voltages necessary for electro-photographic processing
from +30 V according to the control sequence from the control board. When cover open state
is detected, +30 V supply is automatically interrupted to stop the supply of all the high-voltage
outputs.

Output Voltage Use Remarks

Sub-CH -15 µA 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

(3) Photosensor

The photosensor mounted on this power supply unit supervises the paper running state
during printing.

2 - 7

Figure 2-3 shows the sensor layout diagram.

Paper running direction

Roller-exit

Roller-feeder (c)

Outlet sensor

Roller-Heat

Roller-transfer

Sensor

Inlet sensor 1

Inlet sensor 2

Toner sensor

Inlet sensor 1

Inlet

sensor 2

Paper sensor

Roller-regist

Feed roller

Figure 2-3

Function

Detects the leading part of the paper and gives the supervision
timing for switching from hopping operation to feeding opera­tion.
Supervises the paper running state and the paper size accord­ing to the paper reach time and running time.

Detects the form width.

ON: Paper exists.
OFF: No paper exists.

ON: A4 or larger
OFF: Smaller than A4

Sensing state

Paper sensor

Outlet sensor

Toner low sensor

Detects the leading part of the paper.
Supervises the paper running state.

Supervises the paper feed and size according to the time of
arrival to the sensor and the time of passage of paper.

Detects the lack of toner.

ON: Paper exists.
OFF: No paper exists.

ON: Paper exists.
OFF: No paper exists.

ON long: Toner low exists
OFF short: No Toner low exists

2 - 8

2.3 Electro-photographic Process

2.3.1 Electro-photographic process mechanism
This mechanism prints image data from the control board on the paper by electro-photographic

process.

The Figure 2-4 shows the layout of the electro-photographic process mechanism.

Front Hopping Roller

Front Feeder

Roller Assy-Feed

Image Drum Unit

Hopping Motor

1st Hopping Roller

Sub Roller

LED HEAD

Motor-Main

Heat Assy

Face Up stacker

Figure 2-4

2 - 9

(1) Image drum unit

The image drum unit consists of a sensitive drum, a charger, and a developer. The unit forms
a toner image on the sensitive drum, using a electrostatic latent image formed by the LED
head.

(2) Hopping motor

This motor is a pulse motor of 48 steps/rotation that is two-phase excited by the signal from
the control board. It drives the hopping roller of the first tray and the front feed roller via two
one-way clutches according to the direction of rotation.

(3) Motor-Main

This motor is a pulse motor of 72 steps/rotation that is two-phase excited by the signal from

the control board and is the main motor of this mechanism.
(4) Clutch (for Roller-Regist)
(5) Clutch (for Feed Roller)
(6) LED head

Image data for each dot line from the control board is received by the shift register and latch

register. The 4992 LEDs are driven to radiate the image data to the image drum.
(7) Fuser

The fuser consists of a heater, a heat roller, a thermistor and a thermostat.

An AC voltage from the power supply board is applied to the heater under the control of the

HEATON signal from the control board. This AC voltage heats the heater. The control board

supervises the heat roller temperature via the thermistor, and regulates the heater roller at

a predetermined temperature (185 °C : Normal paper, MEDIA TYPE = MEDIUM) by

connecting or disconnecting the AC voltage supply to the heater.

If the heater roller temperature rises abnormally, the thermostat of the heater voltage supply

circuit is activated to cut the AC voltage supply forcibly.

2 - 10

2.3.2 Electro-photographic process
The electro-photographic processing is outlined below. Figure 2-5 shows the electro-photo-

graphic printing process.

1 Charging

The surface of the image drum is uniformly charged with negative charges by applying a
negative voltage to the charge roller.

2 Exposure

Light emitted from the LED head irradiates the negatively charged surface of the image drum.
The surface potential of the irradiated part of the image drum surface is lowered, so that an
electrostatic latent image associated with the print image is formed.

3 Developing and toner recovery

When the negatively charged toner is brought into contact with the image drum, it is attracted
to the electrostatic latent image by static electricity, making the image visible.
At the same time, the residual toner on the image drum is attracted to the developing roller
by static electricity.

4 Transfer

When paper is placed over the image drum surface and a positive charge, opposite in polarity
to the toner, is applied to the reverse side of the paper from the transfer roller, the toner is
attracted by the positive charge and is transferred to the paper. As a result, the toner image
formed on the image drum is transferred to the paper.

5 Temporary cleaning

Residual toner that remains on the image drum without being transferred is made uniform
by the cleaning roller and is temporarily attracted to the cleaning roller by static electricity.

6 Fusing

The toner image transferred to the paper is fused under heat and pressure.
Figure 2-6 shows an electro-photographc process timing chart.

2 - 11

Toner

cartridge

Toner

supply roller

Front

feeder

Path of paper

feeding

Direction of

rotation of the

image drum

Image data

LED head

Power

supply

(Bias voltage)

Exposure

Charging

blade

Doctor

Inlet sensor

roller

Developing

Paper sensor

Developing

Cleaning

Paper

supply

Paper

registration

Transfer

roller

Hopping

roller

Registration

Image

production

roller

Transfer

Power

supply

developing Paper feed Paper hopping

eject

Paper

roller

eject

Paper

Power

supply

(Face down)

roller

Charger

Power

supply

eject

roller

Paper

Figure 2-5

2 - 12

Cleaning

path

Paper

roller

selector

eject

Paper

Fusing

Outlet sensor

(Face up)

Fusing pressure

Heater roller

Paper eject Fusing Cleaning Transfer

DMON-N (DRUM MOTOR)

OFF
ON

2 - 13

Figure 2-6

HMON-N (HOPPING MOTOR)

PWM1-P (CLUCH for hopping)

PWM2-P (CLUCH for REGISTRATION)

PSIN1-N (INLETSENSOR1)

WRSENSE-N (PAPER SENSOR)

PSOUT-N (OUTLET SENSOR)

STB-N (LED HEAD)

OFF
ON

ON
OFF

ON
OFF

OFF
ON

OFF
ON

OFF
ON

OFF
ON

PAPER TRAYPAPER PRINTER

SIMPLEX PRINTING TIMING CHART

STACKER

DMON-N (DRUM MOTOR)

OFF
ON

2 - 14

HMON-N (HOPPING MOTOR)

PWM1-P CLUCH for hopping)

PWM2-P (CLUCH for REGISTRATION)

PSIN1-N (INLETSENSOR1)

WRSENSE-N (PAPER SENSOR)

PSOUT-N (OUTLET SENSOR)

Figure 2-7

STB-N (LED HEAD)

DUPMON-N (MAIN MOTOR in DUPLEX
UNIT)

CLON-P (CLUCH in DUPLEX UNIT)

SLON-P (SOLENOID in DUPLEX UNIT)

DUPINSNS-N (INLET SENSOR in
DUPLEX UNIT)

DUPRSNS-N (REAR SENSOR inDUPLEX
UNIT)

DUPFSNS-N (FRONT SENSOR in
DUPLEX UNIT)

PAPER PRINTER PRINTER STACKERDUPLEX UNIT

OFF
ON

ON
OFF

ON
OFF

OFF
ON

OFF
ON

OFF
ON

OFF
ON

OFF
ON

ON
OFF

ON
OFF

OFF
ON

OFF
ON

OFF
ON

PAPER

TRAY

PRINTER/

DUPLEX UNIT

DUPLEX UNIT/

PRINTER

DUPLEX PRINTING TIMING CHART

2.4.3 Process operation descriptions

(1) Hopping

Hoppings from the first tray and the front feeder are effected by a single hopping motor in the
mechanism shown below.

Hopping Motor

Front Feeder

1st Tray

Turning the Hopping motor in direction a (CW) drives the 1st Hopping Roller. Turning the
Hopping motor in direction b (CCW) drives the Front Hopping Roller. Gear C and Hopping
roller bult in one-way bearing, so that turning each of these gears in reverse direction will not
be transmitted to the corresponding roller.

(One-way Clutch build-in )

Front Hopping Roller

(One-way clutch build-in)

Gear C

(CW)

a

b

Hopping Motor

(CCW)

Inlet Sensor

Roller-Regist

Planet Gear

1st Hopping Roller

(One-way clutch build-in)

2 - 15

Gear A

Gear B

Sub Roller

Paper