HP M750 series

Fuser protective function
The protective function detects an abnormal temperature rise of the fuser unit and interrupts power supply
to the fuser heater.
The following three protective components prevent an abnormal temperature rise of the fuser heater:
●
DC controller
◦
The DC controller interrupts power supply to the fuser heater when it detects an abnormal
temperature of the fuser heater.
●
Fuser-heater safety circuit
◦
The fuser heater safety circuit interrupts power supply to the fuser heater when the detected
temperature of the main and sub thermistors is abnormal.
●
Thermal fuse
◦
The thermal fuse is broken to interrupt power supply to the fuser heater when the thermoswitch
detects an abnormal temperature of the fuser heater.
◦
The current detection circuit detects the current value flowing in the fuser heater control circuit.
The DC controller deactivates the FUSER HEATER CONTROL signal and releases the relay to
interrupt power supply to the fuser heater when it detects a specified current value or higher by
the CURRENT DETECTION (FUR_CURRMS) signal.
16 Chapter 1 Theory of operation ENWW