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IMPORTANT SAFETY INFORMATION AND WARNING
[3] L2 (Fixing Heater Lamp) Overheating
Protection Circuit
TH1
TH2
TS1
PSB
RL1
RL2
RL1
RL2
1. Protection function provided by software
This function turns OFF L2 (fixing heater lamp), RL1, and
RL2 (main relays) in the event that the output voltage from
TH1 (fixing temperature sensor 1), read by the CB (control
board), is abnormal.
Caution: Periodically check the surfaces of TH1 and
TH2 that contact the roller, and replace
them if they are abnormal.
The function of RL1 and RL2 must not be
deactivated under any circumstances.
2. Protection function provided by hardware
This function uses a comparator circuit which compares the
output voltage of TH1 and TH2(fixing temperature sensor 2)
with the abnormal judgment reference value.
It disconnects L2, RL1, and RL2 from the circuit in the event
that the output voltage of TH1 or TH2 exceed the reference
value.
Caution: Periodically check the surfaces of TH1 and
TH2 that contact the roller, and replace
them if they are abnormal.
The function of RL1 and RL2 must not be
deactivated under any circumstances.
3. Protection function using TS1 (Thermostat)
If the surface temperature of the upper fixing roller exceeds
a specified value, TS1 will blow, directly cutting off the flow
of current to L2.
Caution: Do not use a piece of wire in place of TS1
under any circumstances.
CB
Comparator
Section
Control
Section
L2
TRC
C - 6
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