Chapter 9
9.5 Protective Functions
9.5.1 Detecting Overheating Using Thermistors
The main thermistor and the sub thermistor of individual rollers may detect any of the following temperatures; in
response, the DC controller issues signals to cut off the heater drive circuit, thereby depriving the heaters of power.
Fixing roller
Pressure roller
External heating roller
9.5.2 Cutting Off the Power Using Thermal Switches
If the reading of the inside temperatures of the thermal switch of individual rollers indicates a temperature higher
hand the following, the thermal switch goes off to stop the power to the fixing heater:
Fixing roller: 220 +/ 8 deg C
Pressure roller: 220 +/ 8 deg C
Outside roller: 250 +/ 10 deg C
9.5.3 Errors
Related Error
E000 (inadequate rise in temperature of the fixing assembly at power on)
The main thermistor (THM1, THM2, THM3) has an open circuit or poor contact. The thermal switch (TP1, TP2,
TP3) has an open circuit. The heater (H1, H2, H3, H4) has an open circuit. The AC driver PCB is faulty. The DC
controller PCB is faulty.
A check is made during initial multiple rotation.
E001 (overheating of the fixing assembly)
The main thermistor (THM1, THM2, THM3) has an open circuit or poor contact. The sub thermistor (THM4, THM5,
THM6) has an open circuit or poor contact. The thermal switch (TP1, TP2, TP3) has an open circuit. The heater (H1,
H2, H3, H4) has an open circuit. The AC driver PCB is faulty. The DC controller PCB is faulty.
A check is made at all times.
9-22
T-9-11
Main (middle)
235 deg C
200 deg C
245 deg C
Sub (end)
245 deg C
210 deg C
247 deg C
0003-2901
0003-2902
0003-2903