Okidata OKIPAGE 20n, OKIPAGE 20dx Maintenance Manual
OKIPAGE20n / OKIPAGE20n/dx
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 OKIPAGE20n / OKIPAGE20n/dx.
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
1.5.1Certification 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/Sensor Board.................................................................................................. 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
2.4.3 Process operation descriptions .................................................................... 2 -14
2.3.4 Revision of LED Head Illumination ............................................................... 2 - 23
2.4 Paper Jam Detection ................................................................................................. 2 - 27
2.5 Cover Open................................................................................................................ 2 - 28
2.6 Toner Low Detection.................................................................................................. 2 - 29
2.7 Stacker-full Detection................................................................................................. 2 - 31
2.8 Page Size Detection .................................................................................................. 2 - 31
2.9 PostScript ROM module (BOARD-MSM or BOARD-FSL)......................................... 2 - 31
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 ......................................................................... 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-Resist ....................................................................................... 3 - 17
3.3.12 Motor -Main .................................................................................................. 3 - 18
3.3.13 Guide Assy-Eject .......................................................................................... 3 - 20
3.3.14 Heat Ass’y .................................................................................................... 3 - 21
3.3.15 Roller feed (C) ............................................................................................. 3 - 22
3.3.16 Roller Assy-BK ............................................................................................. 3 - 23
3.3.17 The feed roller .............................................................................................. 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 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 Paper end lever ........................................................................................... 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 of Regist ........................................................................................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
B RS-232C SERIAL INTERFACE ............................................... B - 1
C DUPLEX UNIT.......................................................................... C - 1
D Second/ Third Paper Feeder.................................................. D - 1
E Multi Feeder ............................................................................ E - 1
1. CONFIGURATION
1. CONFIGURATION
1.1 System Configuration
OKIPAGE20n / OKIPAGE20nDX consists of control and engine blocks as the standard
configuration (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
230/240V
Face up
stacker
*
*
Toner Cartridge
Front Feeder
LAN etc.
OKI HSP
interface board
(Option)
Extension RAM
(Option)
4MB/ 8MB
Extension
Flash ROM
Memory
: Paper feeding
: Singal flow
PostScript
Board
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 OKIPAGE20n / OKIPAGE20nDX. They are sold
separately from the printer unit.
(1) Multi Feeder
(2) Second/ Third Paper Feeder
(3) DUPLEX Unit
1 - 3
(3) RAM module (72 pin SIMM, 1 MB/2 MB/4 MB/8 MB/16 MB/32 MB)
(4) Flash ROM Memory (72 pin SIMM, 4MB/8MB) module
(5) PS ROM module
1 - 4
1.4 Specification
(1) Type Desk top
(2) External dimensions Height 13.2” (336 mm)
(excludes protruding Width 14.4” (366 mm)
Portion) Depth 18.2” (462 mm)
(3) Weight 18.6 kg (41 lbs) If Installed Duplex 20.9 kg (46.1 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
(6) Printing speed First print: 10 sec.
Continuous print: 20 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
(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 dB (A) or less
At standby: 45 dB (A) or less
Power save mode: 43 dB (A) or less
(14) Consumables Toner cartridge kit 5,000 (5% duty)
Image drum cartridge 30,000 (at continuous printing)
18,000 (3 page/job)
11,000 (1 page/job)
1 - 6
1.5 Safety Standards
1.5.1 Certification label
The safety certification label is affixed to the printer in the position below.
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
OKIPAGE20n / OKIPAGE20nDX consists of a main control board, a power supply/sensor board,
a driver board, 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 OKIPAGE20n / OKIPAGE20nDX block diagram.
2 - 1
FLASH ROM
Module
or
PS ROM
Module
MAIN BOARD (BOARD-AAA)
DUPLEX unit
MULTI feeder
Parallel
I/F
RS232C
I/F
OKI HSP
I/F
(Optional)
ROM
DRAM
Module
DRAM
7407
75188
OKI
HSP
Board
(Optional)
3V 5V +8V -8V 38V
CPU
LSI
EEPROM
TRANSISTOR
TRANSISTOR
DRIVER
DRIVER
2nd tray
Paper end sensor
Paper near end sensor
BOARD PXC
CL
CL
M
M
Operator panel
LED HEAD
3rd tray
Tray size
sensor board
POWER
SUPPLY
UNIT
(AC120V/240V)
FILTER CIRCUIT
LOW VOLTAGE
GENERATION
CIRCUIT
COVER
OPEN
Figure 2-1 OKIPAGE20n / OKIPAGE20nDX block diagram
SW
DRIVER
DRIVER
COVER
OPEN
SW
POWER
SUPPLY
UNIT
(high voltage)
LSI
0V
HIGH
VOLTAGE
CIRCUIT
Inlet sensor1
paper sensor
Inlet sensor2
Toner sensor
CH
TR
DB
SB
CL
THERMISTOR
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 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 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 operator panel, EEPROM, and options
Control of a LSI in the power/sensor board
I/O port Inputting/outputting of sensor, signal and motor signal
Option I/O interface Control of OKI HSP interface
(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)
This LSI is used as a peripheral device of the CPU and has the following fanctions.
Built in device Function
Serial I/O port Control of option unit (2nd/ 3rd Tray, Multifeeder, Duplex unit)
I/O Bort Inputting/ Outputting of sensor, signal and motor signal
(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
2 - 4
to cause the interface time-out at the host side.
(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 DTRLO)
• 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.
Printer
Network, etc.
Control board
LAN
expansion board
OKI HSP
interface
Fig. 2-2
2 - 5
(For the electrical/physical characteristics of the OKI HSP interface, see the OKI HSP interface
technical manual.)
(7) RAM module
• Pin layout
• Basic specificaton
- Type: 72 pins SIIM (32 bits buss width)
- Access time: 60ns, 70ns, 80ns, 100ns
- Capacity: 1, 2, 4, 8, 16 or 32MB
- Parity: None
(8) Flash ROM Memory module
1363772
Board-FSL
1363772
• Pin layout
• Basic specificaton
- Type: 72 pins SIIM (32 bits buss width)
- Access time: 90ns
- Capacity: 4 or 8MB
(9) PS ROM module BOARD
PS ROM module is BOARD-MSM or BOARD-FSL
BOARD-MSM
or
BOARD-FSL
1363772
BOARD MSM consists of MASK ROM
BOARD FSL consists of Flash ROM (8MB).
• Pin layout
• 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/Sensor Board
The power/sensor board 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
–8 V Local Talk 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 -1.5 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/-1300V Voltage applied to clearimng roller
(3) Photosensor
The photosensor mounted on this power/sensor board 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
Paper near-end
sensor 2
Inlet sensor 1
sensor
Paper sensor
Roller-regist
Paper end sensor
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
Paper end sensor
Toner low sensor
Paper near-end 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.
Detect the end of the paper.
Detects the lack of toner.
Detect the near-end of the paper
ON: Paper exists.
OFF: No paper exists.
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
ON:
OFF:
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 Feeder
Hopping Motor
Roller Assy-Feed
Image Drum Unit
LED HEAD
Figure 2-4
Heat Assy
Face Up stacker
Motor-Main
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 drum 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) Clatch (for Roller-Regist)
(5) Clatch (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 ~ 188°C) 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
Doctor
Developing
Charging
blade
Inlet sensor
roller
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
PMON-N
RMON-N
DMON-N
INSNS
WRSNS
OUTSNS
LEDSTB
IN Sensor OFF Paper Sensor
OFF
Feed StopOut Sensor
OFF
Feed start
Figure 2-6
2 - 13
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
First Tray
Turning the Hopping motor in the “a” direction drives the hopping roller of the first tray.
Turning the Hopping motor in the “b” direction drives the Hopping roller of the front feeder.
Gear C and Hopping roller contain one-way bearing, so that turning each of these gears in
reverse direction will not be transmitted to the corresponding roller.
a
One-way Clutch Gear C
b
Inlet Sensor
Hopping Rooler
Roller-Regist
One way clutch Hopping Rooler
Gear B
Sub Roller
Gear A
2 - 14
(a) Hopping (1st tray)
1 Rotating the pulse motor in the direction b (CW direction) drives the hopping roller
of the front feeder to advance the paper until the inlet sensor turns on. At the same
time, Gear B rotates as well as Gear A and the sub roller is driven. Although Gear
C is also rotating due to an all-time raotation of the main motor in direction c, the
feeder roller would not rotates because the clutch (feed) is turned off.
After the hopping roller of the front feeder is driven, feed a paper by 30 mm and then
turn on the clutch (feed) to rotate the feed roller.
When the pulse motor is driven, one-way clutch gear c also rotates simultaneously.
However the hopping roller of the front feeder would not rotate due to the one-way
bearing.
2 After turning on the inlet sensor, the paper advances further by a predetermined
length until it hits the registration roller. (The skew of the paper can thus be
corrected.)
Roller Feed
Clutch (Feed)
Gear D
Inlet Sensor
Roller-Regist
Gear E
Clutch (Regist)
c
Main Motor
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(b) Hopping (front feeder)
1 Rotating the pulse motor in the direction b (CCW direction) drives the hopping roller
of the front feeder to advance the paper until the inlet sensor turns on. At the same
time, Gear A also rotates. But the hopping roller of 1st tray would not rotate due to
the one-way bearing. Also, the sub-roller would not rotate by a disengagement of
the linkage with a planetary gear (because the planetary gear is moved in direction
d).
A cam to push down the front feeder plate is attached on each of the ends of the
hopping roller shaft. These cams push down the front feeder plate when the
hopping operation is not performed so as to facilitate the setting of paper into the
tray. A microswitch is provided under the front feeder plate to detect that the front
feeder plate is at the lower position. When the front feeder plate is at the lower
position, this microswitch causes the motor to stop.
Hopping Roller
(Front Feeder)
Front Feeder Plate
Hopping Roller
One-way clutch Hopping roller
Inlet Sensor
Roller-Regist
Paper
Sub Roller
2 After turning on the inlet sensor, the paper advances further by a predetermined
length until it hits the registration roller. (The skew of the paper can thus be
corrected.)
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