Safety Circuits - Konica Minolta 7085/FORCE 85 Service Manual

SAFETY CIRCUITS

This machine is provided with the following safety
circuits to prevent machine faults from resulting in
serious accidents.
[1] Overall protection circuit
[2] L2, L3, and L4 (fixing heater lamps) overheating
prevention circuit
These safety circuits are described below to provide
the service engineer with a renewed awareness of
them in order to prevent servicing errors that may impair
their functions.
[1] Overall Protection Circuit
CBR1
1. Protection by CBR1 (circuit breaker 1)
The CBR1 interrupts the AC line instantaneously
when an excessive current flows due to a short
in the AC line.
Caution: The CBR1 function must not be
deactivated under any circu-
mstances.
NF NF2
xvii
SAFETY AND IMPORTANT WARNING ITEMS
[2] Protection by L2, L3, and L4 (fixing
heaters) overheating prevention
circuit
CB
Control
section
1. Protection by software
The output voltage from TH1 (fixing temperature
sensor 1) is read by the CPU. If this voltage is
abnormal, L2 (fixing heater lamp 1), L3 (fixing
heater lamp 2), and L4 (fixing heater lamp 3),
and RL1 (main relay) are turned OFF.
Caution: Do not change the gap between
the roller and TH1. When repl-
acing TH1, check the specified
mounting dimensions.
The RL1 function must not be
deactivated under any circum-
stances.
RL1
ACDB
RL driver
RL1
section
TS1
L2
CBR2 *1
AC driver
L3
section
TS2
L4
*1: 7075 only