Fixing System Here, you will learn about the protective mechanisms of the machine’s fixing system.

Protective Mechanism

　

○Purpose : Here, you will learn about the protective mechanisms of the machine’s fixing system.

　

　

1. Outline

If any of the following of the machine fails to operate normally, overheating of the fixing heater will be a possibility. In the light of this, the machine is equipped with a mechanism to protect against overheating of the fixing assembly in the event of a fault in any of these components:

a. Protection by CPU: Used when a fault occurs in the thermistor or a short circuit occurs in the triac. b. Protection by hardware circuit: Used when a fault occurs in the CPU (CPU going awry). c. Protection by thermal switch: Used when both CPU and hardware circuit go out of order.

　

These protective mechanisms are characterized as follows:

　

a. Protection by the CPU

The CPU detects a fault in TH1 or TH2, and cuts the drive to the triac or the relay.

∙ turns off the triac 1/2 -> cuts off the drive to the fixing heater

∙ turns off the relay -> cuts off the power to the fixing heater

　

b. Protection by the Hardware Circuit

The safety circuit detects an abnormally high reading of a thermistor, and cuts off the drive to the triac or the relay.

∙ turns off the triac 1/2 -> cuts off the drive to the fixing heater

∙ turns off the relay -> cuts off the power to the fixing heater

　

c. Protection by the Thermal Switch

The thermal switch melts under heat, thus cutting off the power to the fixing heater.