Controlling The Fixing Temperature - Canon GP335 Service Manual

CHAPTER 9 FIXING SYSTEM
C. Controlling the Fixing Temperature
1. Outline
The temperature of the copier's upper fixing roller is monitored by the main thermistor (TH1)
and the sub thermistor (TH2), and is controlled by the DC-CPU*, which varies the main heater
drive signal (H1-D) and the sub heater drive signal (H2-D) according to the levels of TH1 and TH2.
Image processor PCB
DC
-CPU
Figure 9-103 Major Parts Used for Fixing Temperature Control
9-6
DC controller PCB
Upper fixing roller
TH1-S
TH1
TH2
TH2-S
Error
detection
circuit
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
RL-D
RL1
THSW1
H1 H2
H1-D
H1-ERR
SSR
H2-ERR
H2-D
0V
Door switch
SW2
Main power
switch
SW1
Leakage
power
breaker