Sharp AL-800 (serv.man3) Service Manual ▷ View online
d. OPC drum surface potential
<1> OPC drum surface potential shift in printing
<2> OPC drum surface potential and developing bias
voltage during developing
-310V
-850V
OPC drum surface potent
ial (-V)
Charging/
cleaning
cleaning
Laser
beams
beams
Dark area
potential
potential
Toner attraction
potential
potential
Light area potential
Exposure Residual toner
collection/
Development
Development
Time (OPC drum rotating angle)
Transfer
Developing
bias
bias
Charging
-310V
Start
OPC drum surface potent
ial (-V)
During developing
End
Developing
bias
bias
Light area potential
Time (OPC drum rotating angle)
Dark area
potential
potential
1 – 24
E. Fusing/paper exit section
(1) Outline
Toner attracted to the paper in the transfer section is fused by heat
and pressure of the heat roller. The heat roller is of thin aluminum
roller which is high heat conductivity, minimizing the warm up time.
The heat roller surface temperature is detected by the fusing
temperature sensor to maintain the fusing temperature at a constant
level (160/155 ˚C).
and pressure of the heat roller. The heat roller is of thin aluminum
roller which is high heat conductivity, minimizing the warm up time.
The heat roller surface temperature is detected by the fusing
temperature sensor to maintain the fusing temperature at a constant
level (160/155 ˚C).
(2) Major parts
No.
Parts
MODEL
Note
Code Signal name
Name
Type
Function/operation
Active condition
1
Heat roller
Heats toner on the paper and
fuses onto the paper.
fuses onto the paper.
LOW (0V) when
paper is
detected.
paper is
detected.
2
POUT POUT IN
Paper exit detector
Photo transmission
sensor
sensor
Detects paper exit.
3
RTH IN
Fusing temperature
sensor
sensor
Thermistor
Detects the heat roller
surface temperature.
surface temperature.
4
Temperature fuse 1
(Fusing section)
(Fusing section)
Mold
Assures safety in overheating.
5
Temperature fuse 2
(Fusing section)
(Fusing section)
Mold
Assures safety in overheating.
6
HL
Heater lamp
Halogen lamp
Heats the heat roller.
100V series 10V 500W
120V series 120V 500W
200V series 230V 500W
120V series 120V 500W
200V series 230V 500W
7
Pressure roller
Applies a pressure to the
heat roller and paper to
improve fusing efficiency.
heat roller and paper to
improve fusing efficiency.
8
Paper exit roller
Discharges paper after fusing.
9
Separation pawl
Separates paper from the
fusing roller mechanically.
fusing roller mechanically.
10
Paper exit roller
Discharges paper outside the
machine after fusing.
machine after fusing.
11
Pressure spring
Applies a pressure to the
heat roller, paper, and
pressure roller to improve
transfer efficiency.
heat roller, paper, and
pressure roller to improve
transfer efficiency.
7)
8)
11)
9)
1)
9)
10)
5)
4)
3)
2) POUT
6)
7)
8)
11)
1)
11)
10)
9)
6)
3)
2) POUT
4)
5)
1 – 25
(3) Operation
a. Wiring diagram
b. Operation
The heater lamp ON/OFF is controlled by the detection signal (volt-
age value) from the thermistor to maintain the heat roller surface
temperature at the optimum level.
age value) from the thermistor to maintain the heat roller surface
temperature at the optimum level.
The heat roller surface temperature is controlled to 160/155 ˚C in the
print mode and to 80 ˚C in the pre-heat mode.
print mode and to 80 ˚C in the pre-heat mode.
As a protective measure in case of abnormally high temperature in
the fusing section, two temperature fuses are provided in the heater
lamp power line.
the fusing section, two temperature fuses are provided in the heater
lamp power line.
The heater lamp is lighted by the AC power source.
Heat roller:
The heat roller is made of aluminum
tube coated with teflon to provide a good
separation capability.
tube coated with teflon to provide a good
separation capability.
Heater lamp:
A halogen lamp is used as the heater
lamp.
lamp.
Pressure roller:
Silicon rubber is used to provide enough
pressure.
pressure.
Thermistor:
A chip-type thermistor of good response
is used to detect the heat roller surface
temperature.
is used to detect the heat roller surface
temperature.
Temperature fuse (132 ˚C): The temperature fuse (132 ˚C) is at-
tached to the fusing cover. When the
fusing cover ambient temperature be-
comes abnormally high, this fuse is
blown off.
fusing cover ambient temperature be-
comes abnormally high, this fuse is
blown off.
Temperature fuse (187 ˚C): The temperature fuse (187 ˚C) is closely
attached to the heat roller. When the
heat roller temperature becomes abnor-
mally high, this fuse is blown off.
heat roller temperature becomes abnor-
mally high, this fuse is blown off.
Separation pawl:
The separation pawl separates paper
from the heat roller mechanically.
from the heat roller mechanically.
CPU
HLON
HLON-
RTH
HLL
1/3
CN603
(IC5)
HLN
2/4
CN603
GND
1
CN2
2
RTHN
COMP
AMP
AC POWER IN
PR
RTH
+24V
1
CN801
2 NC
3 +24VS
3 +24VS
DRIVER
PR
ASIC
(IC202)
+24V
MCU(PCU) PWB
POWER SUPPLY PWB
Gate
Temperature fuse
(132 C)
(132 C)
Fusing section
Temperature fuse
(187 C)
(187 C)
Heater
lamp
Thermistor
High voltage power PWB
1 – 26
F. Drive section
(1) Outline
The main motor drives the paper feed section, the transport section,
the image process section, and the fusing section . The main motor
drive circuit is built in the high voltage power PWB.
the image process section, and the fusing section . The main motor
drive circuit is built in the high voltage power PWB.
(2) Major parts
No.
Parts
Note
Code
Name
Type
Function, operation
1
MM
Main motor
Stepping motor (+24V)
Drives the paper feed section, the paper
transport section, the fusing section, and
the image process section.
transport section, the fusing section, and
the image process section.
2
Paper feed section drive
gear
gear
Transmits the main motor power to the
paper feed section.
paper feed section.
3
Imaging process/
fusing section drive gear
fusing section drive gear
Transmits the main motor power to the
imaging process section and the fusing
section.
imaging process section and the fusing
section.
(3) Wiring diagram
2)
1)
3)
MEN
ASIC
(IC8)
MCU(PCU)PWB
MMT0
MMT1
CPU
(IC5)
1
2
2
3
4
4
MA
MA-
MA-
MB
MB-
MB-
CN804
High voltage power PWB
Main motor
Paper feed roller
Heat roller
Pressure roller
Pressure roller
Paper exit roller
Developing cartridge
Photoconductor cartridge
Transfer roller
Motor
driver
driver
1 – 27
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