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21
3. Fuser Temperature Control Circuit
The fuser temperature is controlled by IC1 on the SC PC Board, which contains A/D (Analog/Digital)
converters ANI0 to ANI7. The Fuser Temperature Control Circuit uses A/D converter, ANI1. When the
PC001 drive current is transmitted from the SC PC Board to the LVPS(PSU), the Fuser Lamp turns ON.
IC23 is a comparator with open output at pins 1 and 7 and is used as an abnormal temperature detection
circuit. IC23, pin 1, has a high impedance when Q35 is activated, turning ON the Fuser Lamp.
An abnormal temperature is detected when the VTH voltage level becomes higher than V+, forcing IC23,
pin 1 Low and deactivating Q35.
Abnormally low and high temperatures, as well as Thermistor release status, are detected by IC1 (CPU)
programming.
converters ANI0 to ANI7. The Fuser Temperature Control Circuit uses A/D converter, ANI1. When the
PC001 drive current is transmitted from the SC PC Board to the LVPS(PSU), the Fuser Lamp turns ON.
IC23 is a comparator with open output at pins 1 and 7 and is used as an abnormal temperature detection
circuit. IC23, pin 1, has a high impedance when Q35 is activated, turning ON the Fuser Lamp.
An abnormal temperature is detected when the VTH voltage level becomes higher than V+, forcing IC23,
pin 1 Low and deactivating Q35.
Abnormally low and high temperatures, as well as Thermistor release status, are detected by IC1 (CPU)
programming.
GND
GND
Q35
3
2
R188
R195
3
IC23
4
1
2
2
2
R189
GND
R184
R194
C156
R303
+5v
+24V
+3.3V
+3.3V
+3.3V
D13
C202
GND
PC001
1
2
6
4
+24v
R221
Thermistor
SNSE PCB
PSU (LVPS)
pSSRA
8
1
GND
Q34
3
1
Q32
3
1
79
SC PCB
2
1
CN7
TH2
D12
TH2
11
CN4
11
CN103
Fuser Temperature Control Circuit Diagram
(ANI1)
IC1
CPU
R199
R190
R191
IC3
SHINE
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