Protective Functions - Canon CLC 1120 Service Manual

B. Protective Functions
The copier is equipped with the following six protective mechanisms to prevent malfunction of
the fixing heater:
a. The DC-CPU monitors the voltage of the thermistor (THM1, THM3). When it detects
210°C or more, the copier will indicate 'E000' on the control panel, generate SHUTOFF*
signal, and turn off the main switch (SW1).
b. If the copier detects that the SSR is on (USSRD or LSSRD=1) in the absence of the heater
drive signal from the DC-CPU, the copier will indicate 'E000' on the control panel, and
will cut off the power to the fixing heater.
c. If the gate array detects that the difference in thermistor voltage between THM1 and THM2
(upper thermistors) or between THM3 and THM4 (lower thermistors) is about 1.6 V (about
50°C) or more, the copier will indicate 'E000' on the control panel, and will cut off the
power to the fixing heater.
d. If the gate array detects that the voltage of any of the four thermistors (THM1, THM2,
THM3, THM4) is about 1.0 V (about 220°C) or more, 'E000' will be indicated on the
control panel and, thereafter, the power to the fixing heater will be cut.
e. If the SSR is on (USSRD or LSSRD=1) in the absence of heater drive signal from the DC-
CPU, the copier will indicate 'E004' on the control panel, and will cut off the power to the
fixing heater.
f. If the internal temperature of the fixing thermal switch (TP2, TP3) of the upper roller or the
lower roller exceeds about 220°C, the copier will turn off the respective thermal switch and
the power to the fixing heater.
Caution:
Once open, the contact of a thermal switch will not close (even after recovery to normal
temperature). Do not use a thermal switch whose contact has opened once.
Resetting E000/E004/E008
1) Remove the cause.
2) Start service mode, and select FUNCTION>CLEAR>ERROR.
3) Press the OK key.
4) End service mode, and turn off and then on the power switch.
COPYRIGHT © 1999 CANON INC. CANON CLC1120/1130/1150 REV.0 MAR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 8 FIXING SYSTEM
8-11