Read Sharp AL-840 (serv.man5) Service Manual online
C. Functional parts
(1) Sensor, detector
No.
Parts
Note
Code
Signal name
Name
Type
Function/operation
Active condition
1
MHPS
MHPS
Scanner home position
sensor
sensor
Photo
transmission
sensor
transmission
sensor
Detects the scanner home position.
This signal is used to control image
scanning operation.
This signal is used to control image
scanning operation.
HIGH (5V) when the
home position is
detected.
home position is
detected.
2
SL SENSOR
PDA/PDK
Scanner lamp light
quantity sensor
quantity sensor
Photo diode
Detects the scanner lamp light
quantity. This signal is inputted to
the scanner lamp control PWB to
control the scanner lamp drive
voltage to maintain a constant level
of light quantity.
quantity. This signal is inputted to
the scanner lamp control PWB to
control the scanner lamp drive
voltage to maintain a constant level
of light quantity.
Analog signal (0
∼
0.5V)
3
PAPER SIZE
SW
SW
PAPER SIZE
IN
IN
Paper width detector
Mechanical
switch (Micro
switch)
switch (Micro
switch)
Detects the paper width. This signal
is used to control the laser beam
radiation area.
is used to control the laser beam
radiation area.
LOW (0V) when the
max. width is detected.
max. width is detected.
4
PE SENSOR
PEMP IN
Paper empty detector
Photo
transmission
sensor
transmission
sensor
Detects paper on the paper tray.
LOW (0V) when paper
is detected.
is detected.
5
SYNC
SYNC IN
Laser beam sensor
Bin diode
Detects the laser beam position.
This signal is used to control the left
image print start position.
This signal is used to control the left
image print start position.
LOW (0V) when laser
beam is detected.
beam is detected.
6
CCD SENSOR
CCD OUT
CCD (image) sensor
CCD
Scans document images (photo
signals) and converts them into
electrical signals.
signals) and converts them into
electrical signals.
Digital signal (8Bit)
7
PIN SENSOR
PIN
Paper in detector
Photo
transmission
sensor
transmission
sensor
Detects whether the fed paper is
transported to the transfer position or
not.
transported to the transfer position or
not.
LOW (0V) when paper
is detected.
is detected.
8
TS
TS IN
Toner empty sensor
Photo
transmission
sensor
transmission
sensor
Detects remaining toner in the
developing cartridge.
developing cartridge.
HIGH (5V) when toner
empty is detected.
empty is detected.
9
RTH
RTH IN
Fusing temperature
sensor
sensor
Thermistor
Detects the fusing roller surface
temperature.
temperature.
Analog signal (2.0
∼
5.0V)
10
POUT
POUT IN
Paper exit detector
Photo
transmission
sensor
transmission
sensor
Detects discharge of paper.
LOW (0V) when paper
is detected.
is detected.
11
DSW
DSW
Front cover open/close
switch
switch
Micro switch
Turns on/off the
+
24V power line
(power source for the motor, the high
voltage PWB, and solenoids) when
opening/closing the front cover for
safety. (Detects open/close of the
front cover at the same time.)
voltage PWB, and solenoids) when
opening/closing the front cover for
safety. (Detects open/close of the
front cover at the same time.)
Close
8) TS
9) RTH
10) POUT
11) DSW
1) MHPS
2) SL SENSOR
7) PIN SENSOR
6) CCD SENSOR
3) PAPER SIZE SW
4) PE SENSOR
5) SYNC
5 – 14
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