Protective Functions - Canon iR4570 Series Service Manual

Chapter 9

9.4 Protective Functions

9.4.1 Protective Functions
0006-6009
iR2270 / iR2870 / iR3570 / iR4570 / iR3530
As part of its protective mechanism, the machine has a thermo switch, triacs, and a relay. Protective measures
according to location are described below:
1. When the thermistor is out of order
Software detects a failure, and the triac and the relay are turned off.
The thermo switch is turned off.
2. When the CPU goes out of control
The latch circuit detects the excessive temperature rise, and the relay is turned off.
The thermo switch is turned off.
3. When the triac short-circuits
Software detects failure, and the relay is turned off.
The latch circuit detects the excessive temperature rise, and the relay is turned off.
The thermo switch is turned off.
Protective Circuit Block Configuration Diagram
DCON
and
CPU
and
and
A/D
and
Tr
S_TH M_TH
AC driver
SW
F-9-5
9-9