Read Sharp AL-1622 (serv.man16) Service Manual online
AL-1611/AL-1622
ELECTRICAL SECTION
13 – 15
H. TONER SUPPLY MOTOR DRIVE CIRCUIT
The IC31 is the motor control IC, which generates the pseudo AC waveform with the pulse signals (TM, TM-) outputted from ASIC, driving the toner
supply motor.
3. CCD PWB
The CCD PWB is provided with the CCD (Charge-Coupled Device), the differential amplifier which amplifies image signals, and the AD convertor
which converts the amplified image signals into digital signals.
The DC power and the pulse supply pins necessary for operating the CCD image sensor are the power source (CD pin), GND (SS pin), shift pulse
(SH pin), transfer pulse (
φ
1 pin), (
φ
2 pin), reset pulse (/RS pin), clamp pulse (/CP pin), and sampling (/SP pin).
interval between inputting two SH signals is called the photo accumulation time.
The signals are transfered to the register, then to the shift register sequentially by transfer pulses
φ
1 and
φ
2 and to the floating capacitor section
where electric signals are voltage-converted. Electric charges from the even number pixel shift register and the odd number pixel shift register are
flowed to the floating capacitor section alternatively.
flowed to the floating capacitor section alternatively.
The /RS signal is the reset signal of the CCD output signal. The CCD output is expressed as electric charges equivalently accumulated in the capac-
itor. Therefore, to take the CCD output data one pixel by one pixel, one output data must be cleared after it is outputted. The /RS signal is used for
that operation.
The /SP pulse signal is the peak hold signal of the signal voltage.
The output signal from the CCD is amplified by about 4.7 times greater in the differential amplifier circuit in the CCD PWB.
Differential amplification is made for the signal output (OS) and the compensation output (DOS).
The amplified CCD signal output is sent to the clamp circuit. In the clamp circuit, the black level is clamped to 2V at the BCLK signal timing by the
analog switch. The clamped voltage is maintained for one line by the coupling capacitor. The clamped analog signal is impedance-converted and
analog switch. The clamped voltage is maintained for one line by the coupling capacitor. The clamped analog signal is impedance-converted and
inputted to the AD convertor.
The analog signal inputted to the AD convertor is converted into 8bit digital data and passed to the PCU PWB.
The machine employs the TCD1501C as the image sensor. The TCD1501C is the reduction type high sensitivity CCD linear sensor of one-output
24V
2
9
1
4
IC27
TA7291S
IN1
IN2
GND
6
7
7
3
8
5
5
OUT1
OUT2
V5
VCC
GND
Vref
47K
47K
+
VCC
1
0µ/
1
6
V
TM
+
IC1 CPU
DTC114EKA
4.7K(1/4W)
76/
PWOFF
PWOFF
10K
1SS133
10K
4.7K(1/4W)
47K(1/4W)
TMD
/TMD
DTC114EKA
1SS133
10 /25V
229
/TM
228
TM
/TM
TM
/PWOFF
IC13
Image
ASIC
Image
ASIC
CCD analog shift register 1
CCD analog shift register 2
Photo diode
12V
Output
Photo diode
Accumulation electrode
Shift electrode
To Shift register
Photo energy
