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Technical Overview > Fixing System > Various Control Mechanisms > Protective Functions
Technical Overview > Fixing System > Various Control Mechanisms > Protective Functions
Various Control Mechanisms
■
Fixing Temperature Control
●
Heater Temperature Control
The heater temperature control is to keep the fixing heater in the fixing film unit to the
specified temperature.
The engine controller monitors the fixing heater temperature detection signal (FSRTH) and
outputs the fixing heater drive signal (FSRD) according to the detected temperature.
The fixing heater drive PCB controls the fixing heater according to this signal to keep the
fixing heater temperature within the target values.
(220-240V model only)
FU101
RL101
+24V
FREQSNS
FSRD
24VOFF
FSRTH
CPU
Engine controller
Fixing heater (H1)
Pressure
roller
Thermistor (TH1)
Thermal fuse (TP1)
Fixing film
Low-voltage
power supply
Frequency
detection
circuit
Fixing control
Relay drive
circuit
Fixing heater
drive circuit
Fixing heater
safety circuit
F-2-31
There are 11 types of target fixing temperature depending on the fixing mode.
These types are according to the paper type settings and resolution settings on a driver.
fixing mode
The number of sheets Normal Heavy1 Heavy2 Light OHT Envelope Envelope2 Quiet
1
185
175
185
160
165
165
145
150
2 to 6
185
175
185
160
165
165
143
150
7 to 26
185
175
185
160
165
165
140
150
27 to 41
185
175
185
160
165
165
140
150
42 to 76
185
173
185
160
165
165
138
148
77 to 150
183
170
185
160
165
165
135
145
151 to 197
180
170
185
160
165
165
135
145
More than 198
180
170
185
160
165
165
135
145
fixing mode
The number of sheets Post
Nomal
N/N
Nomal
(Copy)
1
185
185
190
2 to 6
185
185
190
7 to 26
185
185
190
27 to 41
185
185
190
42 to 76
185
185
190
77 to 150
185
183
188
151 to 197
185
180
185
More than 198
185
180
185
■
Protective Functions
●
Protective Function of fixing assembly
Host machine carries the following 3 functions to prevent the fixing heater from overheating.
1) Protective function by CPU
CPU of engine controller monitors the thermistor (TH1) temperature consistently.
When TH1 reaches approx 220 deg C, CPU determines that the fixing heater is overheating
and stops the fixing heater drive signal (FSRD) output and also turns OFF relays to shut
the power supply to fixing heater.
2) Protection function by fixing heater safety circuit
Fixing heater safety circuit monitors the thermistor (TH1) temperature consistently.
When TH1 reaches approx 235 deg C, it determines that the fixing heater is overheating
and the fixing heater safety circuit turns OFF the relay drive circuit to shut the power supply
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T-2-7
Summary of Contents for MF4500 Series
Page 222: ...5 5 Adjustment Adjustment Mechanical Adjustment ...
Page 224: ...6 6 Trouble Shooting Trouble Shooting Test Print Trouble Shooting Items Version Upgrade ...
Page 230: ...7 7 Error Codes Error Codes Overview Error Codes ...
Page 234: ...8 8 Service Mode Service Mode Overview COPIER FEEDER FAX TESTMODE ...
Page 251: ... Service Tools Solvent Oil List General Circuit Diagram General Timing Chart Appendix ...