Fuser heater protection
The fuser heater protective function detects an excessive temperature rise of the fuser and interrupts
the power supply to the fuser heater.
The following four protective components prevent the fuser heater from excessive rising temperature:
●
DC controller
The DC controller monitors the detected temperature of the thermistor. It releases the triac and
relay to interrupt power supply to the fuser heater when it detects an excessive temperature.
◦
TH1: 223° C (433° F) or higher
◦
TH2: 195° C (383° F) or higher
◦
TH3: 223° C (433° F) or higher
◦
TH4: 195° C (383° F) or higher
◦
TP1: 240° C (464° F) or higher
◦
TP2: 240° C (464° F) or higher
●
Fuser-heater safety circuit
The fuser heater safety circuit monitors the detected temperature of the thermistor. It releases
the triac and relay to interrupt power supply to the fuser heater when it detects an excessive
temperature.
◦
TH1: 230° C (446° F) or higher
◦
TH2: 200° C (392° F) or higher
◦
TH3: 230° C (446° F) or higher
◦
TH4: 200° C (392° F) or higher
◦
TP1: 250° C (482° F) or higher
◦
TP2: 250° C (482° F) or higher
●
Current detection circuit
The inlet current detection circuit monitors the current flowing through the fuser control circuit.
The fuser current detection circuit monitors the current flowing through the fuser heater. The DC
controller deactivates the FUSER HEATER CONTROL signal to interrupt power supply to the
fuser heater when the current of the CURRENT DETECTION signal is higher than a specified
value.
●
Thermoswitch
The contact to the thermoswitch breaks to interrupt the power supply to the fuser heater when
the temperature of the fuser heater is abnormally high.
◦
TS101: 200° C (392° F) or higher
◦
TS102: 200° C (392° F) or higher
◦
TS103: 200° C (392° F) or higher
ENWW Engine-control system 23
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