19. Fusing section
Theory of Operation Ver. 8.0 Jun. 2008
14
0
2
Composition/Operation
19.3.7
Protection from abnormally high temperature
• The machine provides protection against abnormally high temperature of the fusing unit
in the following three steps.
A. < Soft protection >
• When the controlled temperature of each roller is detected higher than the predeter-
mined value for more than 1 second, the temperature is judged to be abnormally high,
and the trouble code appears.
• When the trouble code is displayed, printing will be prohibited.
B. < Hard protection >
• Next level is provided when the level 1 cannot detect due to CPU overrun.
• The heater relay, through the electronic control board, is turned OFF in the second level
operation to block the power supply to the IH heater and the heater lamp.
• When the controlled temperature of each roller is detected higher than the predeter-
mined value, the temperature is judged to be abnormally high, and the trouble code
appears.
• Through these control procedures, the power supply to the IH heater and heater lamps
can be shut down before the thermostat is activated in the third level. It thereby sup-
presses damage to the fusing unit itself.
Roller name
Sensor name
Detected
temperature
(Degrees
centigrade)
Trouble code
Heating roller
NC sensor: TEMS
225
C3725
Fusing high temperature
abnormality_NC sensor
Heating roller thermistor/2:
TH2
270
C3721
Fusing high temperature
abnormality_heating center
Heating roller thermistor/3:
TH3
285
C3722
Fusing high temperature
abnormality_heating edge
Fusing pres-
sure roller
Fusing pressure roller ther-
mistor: TH4
215
C3723
Fusing high temperature
abnormality_pressure
Soaking roller
Soaking roller thermistor/1:
TH5
200
C3724
Fusing high temperature
abnormality_Soaking
2
Roller name
Sensor name: code
Controlled
temperature
(Degrees
centigrade)
Trouble code
Heating roller
Heating roller thermistor/1:
TH1
195
C3721
Fusing high temperature
abnormality_heating center
Heating roller thermistor/2:
TH2
225
Heating roller thermistor/3:
TH3
220
C3722
Fusing high temperature
abnormality_heating edge
Soaking
roller
Soaking roller thermistor/1:
TH5Soaking roller thermistor/
2: TH6
165
C3724
Fusing high temperature
abnormality_Soaking
2
Theory of Operation Y107522-3
Содержание d-Color MF550
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Страница 9: ...Outline Composition Operation Theory of Operation Ver 8 0 Jun 2008 vi Blank Page d Color MF550 MF450...
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