All specifications are subject to change without notice.
40245101TH
HP, LaserJet and PCL5e are trademarks of Hewlett-Packard Co.
PREFACE
This Maintenance Manual describes the field maintenance methods for LED Page Printers.
This manual is written for use by service persons. Please note that you should refer to the Printer
Handbook for the handling and operating methods of the equipment.
ture 77 ˚F (25 ˚C))
(7) Paper feeding methodAutomatic paper feed or manual paper feed
(8) Paper delivery methodFace down
(9) Resolution300 dpi x 300 dpi, 600 dpi x 600 dpi (quasi)
(10) Power input230 VAC +15%, -14% (for OEL/INT)
120 VAC +6%, -15% (for ODA)
(11) Power consumptionPeak:450W
Typical operation:100W
Idle:30W
Power save mode:5W
1 - 4
(12)Temperature and humidity
Humidity
During operation
In storage
Caution:
Temperature and humidity in storage are measured with the OKIPAGE 4w plus/4m
being packed; they are valid for one year.
Temperature
10 to 32 ˚C
–10 to +43 ˚C
20 to 80% RH (relative humidity)
10 to 90% RH (relative humidity)
1.5.1Certification Label
The safety certification label is affixed to the following location of the OKIPAGE 4w:
OKI-INT
4w Plus
1.5.2Warning Label
Warning labels are affixed to the locations that may cause bodily injury.
During maintenance, do work with enough care while following instructions on these warning
labels.
For OEL
1 - 6
For OEL, OKI-INT
For China, TAIWANFor Korea
2.OPERATION DESCRIPTION
2.OPERATION DESCRIPTION
The OKIPAGE 4w Plus/4m consists of a main control board, a high-voltage power supply board,
a power supply unit, and an electro-photographic processor. The OKIPAGE 4w Plus/4m receives
print data from a higher-level interface and sequentially stores it in memory. The OKIPAGE 4w
Plus/4m decodes and edits the received data while storing print data from the interface in
memory. It sequentially transfers the edited data to the LED head for each dot line. The electrophotographic processor then prints the data on sheets of paper.
The display of the higher-level host is used for device operation and status display.
Figure 2-1 is the block diagram of the OKIPAGE 4w Plus/4m.
2 - 1
EEPROM
Parallel
I/F
LED head
Main motor
Electromagnetic
clutch
Sensors
TEMP
TR-VSEN
TR-ISEN
Reset
circuit
10 MHz
MSM65917
(nX-8 core)
Address
latch
EPROM
(52 KByte)
OE
CS
A8 ~ A15
AD0 ~ AD7A0 ~ A7
D0 ~ D3
A0 ~ A10
D0 ~ D7
D-RAM
(512 KB: For INT)
(128 KB: For OEL)
DriverHigh-voltage power I/F
LED
HEAT ON
5V
5V
OVL
CN
Parallel
I/F
Parallel
I/F
LED head
Main motor
Electromagnetic
clutch
LS07
Driver
Main motor
Electromagnetic
clutch
LED head
Driver
Driver
AC output ON/OFF
Switching
power supply
<Power Supply Unit>
<Main Control Board>
<High-voltage Power Supply Board>
LED
Thermistor
EP cartridge
Heater
(Halogen lamp)
AC
(120 V/230 V)
Manual feed sensor
Paper sensor
Outlet sensor
Toner sensor
Cover open switch
LED
Sensors
TEMP
High-voltage
power I/F
TR-VSEN
TR-ISEN
HEAT ON
+24 V
+5 V
0VL
0VP
M
High voltage
power
supply
Figure 2-1 Block Diagram (OKIPAGE 4w Plus)
2 - 2
EEPROM
Parallel
I/F
LED head
Main motor
Electromagnetic
clutch
Sensors
TEMP
TR-VSEN
TR-ISEN
Reset
circuit
10 MHz
MSM65917
(nX-8 core)
Address
latch
EPROM
(52 KByte)
OE
CS
A8 ~ A15
AD0 ~ AD7A0 ~ A7
D0 ~ D3
A0 ~ A10
D0 ~ D7
D-RAM
(512 KByte)
D-RAM
(2 MByte)
DriverHigh-voltage power I/F
LED
HEAT ON
5V
5V
OVL
CN
Parallel
I/F
Parallel
I/F
LED head
Main motor
Electromagnetic
clutch
LS07
Driver
Main motor
Electromagnetic
clutch
LED head
Driver
Driver
AC output ON/OFF
Switching
power supply
<Power Supply Unit>
<Main Control Board>
<High-voltage Power Supply Board>
LED
Thermistor
EP cartridge
Heater
(Halogen lamp)
AC
(120 V/230 V)
Manual feed sensor
Paper sensor
Outlet sensor
Toner sensor
Cover open switch
LED
Sensors
TEMP
High-voltage
power I/F
TR-VSEN
TR-ISEN
HEAT ON
+24 V
+5 V
0VL
0VP
M
High voltage
power
supply
option
Driver IC
Mac I/F
(Option RAM-PCB)
Figure 2-1 Block Diagram (OKIPAGE 4m)
2 - 3
2.1Main Control Board
The main control board consists of a one-chip CPU, a program ROM, a DRAM, an EEPROM, a
host interface circuit, and a mechanism driving circuit. The mechanism driving circuit consists of
a LED head, a main motor, and an electromagnetic clutch.
(1) One-chip CPU
The one-chip CPU is a custom CPU (8-bit internal bus, 8-bit external bus, 10-MHz clock)
incorporating mask ROM and CPU peripheral devices. This CPU has the functions listed in
the table below.
Built-in DeviceFunction
DRAM controller
DMA controller
Parallel interface controller
Video output port
LED STB output port
Timer
I/O port
A/D converter
(2) Program ROM
Program ROM contains a program for the equipment. EPROM is used as program ROM.
When mask ROM in the one-chip CPU explained in (1) above is valid, the EPROM is not
mounted. (For details on short wiring setting, see Section 7.2.)
(3) DRAM
DRAM is used as resident memory.
Controls DRAM.
Transfers image data from Parallel I/F to DRAM, from DRAM to a video output port and
between CPU and DRAM.
Controls the parallel interface.
Controls LED head.
Generates various control timings for monitoring paper feeding and a paper size.
Inputs and outputs the sensor signals and motor signals, etc.
Also performs I/O for EEPROM.
Inputs the feedback signals from a high-voltage generation circuit and thermistor signal.
(4) EEPROM
EEPROM holds the following data:
• Menu data
• Counter value
• Adjustment value
(5) Parallel interface
The parallel interface receives parallel data from the host; it conforms to the IEEE1284
specification.
(6) Macintosh interface <only OKIPAGE 4m>
Mcintosh interfacce receives serial data from the host ; it conforms to the IEEE1284.
2 - 4
2.2Power Supply Unit
The power supply unit supplies +5 V and +24 V to the main control board according to 230 VAC
/120 VAC.
Output voltageApplication
+5 V
+24 V
Used to generate a logic circuit and a high voltage.
Used to drive the motor and electromagnetic clutch.
The power supply unit also contains a heater drive circuit.
2.3High-Voltage Power Supply Board
(1) High-Voltage power supply circuit
The high-voltage power supply circuit generates the following voltages required for the
electro-photographic processor from +5 V according to the control sequence from the main
control board. When the cover is open, +5 V supply is automatically interrupted to stop high-
voltage output.
OutputApplication
CH
–1.35 KV
DB
–300 V/+300 V
SB
–450 V/ 0 V
CB
+400 V
TR
+500 V ~ +3.5 KV/–750 V
Voltage
Voltage to be applied to a charge roller.
Voltage to be applied to a developing roller.
Voltage to be applied to a sponge roller.
Voltage to be applied to a cleaning roller.
Voltage to be applied to a transfer roller.
Caution:
The TR voltage varies with medium and transfer roller impedance.
2 - 5
(2) Sensors
The high-voltage power supply board consists of the high-voltage power supply circuit that
supplies power to the electro-photographic processor system and the photosensor that
detects a paper feeding system and toners.
Figure 2-2 shows the sensor layout drawing.
Exit roller
Outlet sensor
Heat roller
Transfer roller
Paper sensor
Toner
sensor
assy
Manual feed sensor
Paper feeding direction
Feed roller
Hopping
roller
Figure 2-2
SensorFunctionSensing State
Manual feed
sensor
Paper sensor
Outlet sensor
Toner sensor
Monitors whether paper was inserted into the manual feed sensor
section.
Detects the leading part of the paper.
Monitors paper feeding.
Monitors paper feeding and the paper size according to the paper
sensor arrival and passing time.
Detects the low toner status.
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
OFF (short): Toner High
2 - 6
2.4Electro-Photographic Processor
The electro-photographic processor prints out the image data to be sent from the main control
board on sheets of paper. Figure 2-3 shows the layout drawing of the electro-photographic
processor.
(1) Image drum unit
The image drum unit makes a toner adhere to the formed electrostatic latent image with static
electricity. This electrostatic latent image is formed by the lights irradiated from LED heads.
(2) Electromagnetic clutch
The electromagnetic clutch controls the rotation of the hopping roller according to signals
from the control block.
2 - 7
Exit roller
Heat roller
(ø 19.910)
6.85
10
OFF
ON
26.50
Outlet sensor
Cleaning roller
(ø 9.000)
Charge roller
(ø 9.000)
6.77
LED head
Drum roller
(ø 16.000)
Developing roller
(ø 14.000)
17.23
12.72
23.18
20.32
64.60
Single tray
Transfer roller
(ø 15.000)
Hopping roller
OFF
32.00
10
Tray printing
10
ON
OFF
Manual feed sensor
Manual
printing
Feed roller
Paper sensor
2 - 8
Figure 2-3 Layout Drawing of Electro-Photographic Processor
(3) Pulse motor (Main)
This pulse motor of 48 steps/rotation is two-phase excited by the signal from the main control
board; it performs feeding control by switching normal rotation to reverse rotation or vice
versa and turning on/off the electromagnetic clutch. The relationship between the main
motor, electromagnetic clutch, resist gear, drum gear, hopping roller is shown in the table
below and on the subsequent pages.
Main MotorElectromagnetic Clutch
Normal rotation
Reverse rotation
OFF
ON
OFF
Hopping Roller
Non-rotation
Rotation
Non-rotation
Regist GearDrum GearOperation
Non-rotation
Rotation
Rotation
Rotation
Rotation
Rotation
Warm-up
Hopping
Prinitng
(4) LED head
The shift and latch registers receive image data from the main control board for each dot line.
2,560 or 2,496 LEDs are driven to radiate the image drum.
(5) Heat Assy
The heat Assy consists of a heater, a heat roller, a thermistor, and a thermostat.
The power supply unit supplies AC voltage to the heater according to the HEATON signal
from the main control board to heat the heat roller. The main control board monitors the heat
roller temperature via the thermistor and keeps the temperature constant by turning on/off
the heater AC voltage supply.
If the heat roller temperature rises abnormally, the thermostat of the heater voltage supply
circuit functions to forcibly suspend the AC voltage supply.
2 - 9
Exit roller
Heat roller
Transfer roller
Cleaning roller
CH roller
Drum roller
Developing roller
Outlet
sensor
Paper sensor
Hopping roller
TRAY printing
Feed roller
Manual
feed
sensor
Manual printing
2
Roller to be driven by reverse
rotation of pulse motor (Main)
1
Motor to be driven by normal
rotation of pulse motor (main)
Roller control by pulse motor (main)
1
Normal rotation of pulse motor (main): Drum roller, transfer roller, cleaning roller, CH roller, developing roller, heat roller, exit roller rotation
2
Reverse rotation of pulse motor (main): Drum roller, transfer roller, cleaning roller, CH roller, developing roller, heat roller, exit roller, feed roller,
hopping roller rotation
Hopping operation from the tray, however, is performed when the electromagnetic clutch is turned on.
Figure 2-4 Schematic Drawing of OKIPAGE4w Plus/4m Paper Feeding
2 - 10
2.5Electro-Photographic Process
(1) Electro-photographic process
The electro-photographic process is outlined below.
1 Charging
The surface of the OPC drum is charged negatively and uniformly by applying the DC
voltage to the CH roller.
2 Exposure
Light emitted from the LED head irradiates the negatively charged surface of the OPC
drum. The surface potential of the irradiated surface attenuates to form the electrostatic
latent image corresponding to the image signal.
3 Development and residual toner recovery
The negatively charged toner is brought into contact with the OPC drum, adhering to the
electrostatic latent image on the OPC drum by static electricity. This adhesion causes
the electrostatic latent image to change to a visible image.
At the same time, the residual toner on the OPC drum is attracted to the developing
rollerby static electricity.
4 Transfer
When paper is placed over the image drum surface, the positive charge which is
opposite in polarity to that of the toner, is applied to the reverse side by the transfer roller.
The toner is attracted by the positive charge and is transferred onto the paper. This
results in the transfer of the toner image formed on the image drum onto the paper.
5 Cleaning
The cleaning roller temporarily attracts the residual toner on the transferred OPC drum
with static electricity, then returns the toner to the OPC drum.
6 Fusing
The transferred unfused toner image is fused to a sheet of paper by applying heat and
pressure to the image.
Figure 2-5 is a flow for the electro-photographic process.
2 - 11
Paper
holder
section
Manual feed
Control signal
LED head
Power
supply
Exposure
Toner
cartridge
roller
Developing
Paper
supply
Transfer
Manual feed
roller
Hopping
Feed roller
Paper sensor
Transfer roller
sensor
: OPC drum rotation direction
: Paper feeding path
Power
supply
roller
Charge
Paper delivery
Charging
Power
supply
CleaningDevelopment
roller
Cleaning
Paper feeding
Outlet sensor
roller
Paper eject
Fusing
Power
supply
roller
Back-up
Heat roller
Figure 2-5 Flow for Electro-Photographic Process
Paper ejectionFusingCleaningTransferDevelopmentPaper feedPaper hopping
2 - 12
2.5.1Explanation of Each Process Operation
(1) Hopping
As shown in the figure below, the clutch for hopping is turned on/off according to current ON/
OFF to a coil.
When the clutch is OFF
Coil
Hopping gear
Spring for resetting
Clutch plate
Magnetic
substance plate
Pin
Hopping roller
When the clutch is ON
Hopping shaft
Hopping gear
Engagement section
Clutch plate
When the clutch is on, the hopping gear engages with the clutch plate to rotate the hopping
roller.
When the clutch is off, the hopping gear is separated from the clutch plate by the spring for
resetting, disabling the rotation of the hopping roller.
2 - 13
(2) Printing and warm-up
At warm-up
Triple gear
Transfer gear
Resist gear
Idle gear
Planetary gear
a
Pulse motor (main)
Hopping gear
a"
a'
Gear A
Rotate the pulse motor (main) in the a direction. The planetary gear rotates in the a’ direction,
dislocating its position in the a” direction. This causes the planetary gear to be separated from
gear A. The hopping gear will not rotate. The triple gear and transfer gear rotate via the idle
gear to drive the EP unit.
At printing
Transfer gear
Resist gear
Hopping gear
Triple gear
b"
b'
Gear A
The paper is further advanced in synchronization to the print data.
Idle gear
Planetary gear
b
Pulse motor (main)
2 - 14
(3) Charging
Charging is performed by applying DC voltage to the charge roller that is in contact with the
surface of the OPC drum.
High-
voltage
power
supply
OPC drum
Charge roller
(4) Exposure
High-
voltage
power
supply
Light emitted from the LED head irradiates the negatively charged surface of the OPC drum.
The surface potential of the irradiated surface attenuates to form the electrostatic latent
image corresponding to the image signal.
LED head
Charge roller
OPC drum
LED head
2 - 15
Paper
OPC drum
(5) Development
The electrostatic latent image on the surface of the OPC drum is changed to a visible toner
image by applying a toner to it. Development is performed in the contact part between the
OPC drum and developing roller.
1 The sponge roller negatively charges a toner and applies it to the developing roller.
Developing blade
Charge roller
Sponge roller
Developing roller
OPC drum
2 The toner applied to the developing roller is thin-coated by the developing blade.
3 A toner adheres to the exposure part of the OPC drum in the contact part between the
OPC drum and developing roller. This causes the electrostatic latent image to be
changed to a visible image.
2 - 16
(6) Transfer
The transfer roller is composed of conductive sponge material. This roller is set so that the
surface of the OPC drum and sheets of paper will adhere closely.
A sheet of paper is placed on the surface of the OPC drum and the positive charge opposite
to the negative charge of a toner is applied from the reverse side by the transfer roller.
When a high negative voltage is applied from the power supply to the transfer roller, the
positive charge induced on the surface of the transfer roller moves to the paper side at the
contact part between the transfer roller and the sheet of paper. The positive charge on the
lower side of the sheet of paper then causes the negatively charged toner adhering to the
surface of the OPC drum to move to the upper side of the sheet. This enables transfer to the
sheet of paper.
OPC drum
Transfer roller
Paper
High-voltage
power supply
2 - 17
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