14 - 1
FUSER UNIT
1. The Thermistor status counter normally has a value of between 0 and 9.
•
At the power on, if the heater is not turned ON and the copier goes into C41 CALL SERVICE, check the
Thermistor status counter to see if it is 2 or more. If it is 2 or more, be sure to check the thermistor and
heater lamp, and after repair, reset the Thermistor status counter (08-code 400) to 0 and then turn ON
the power switch.
•
2.
Relationship between the output voltage and the fusing temperature.
•
200°C corresponds to approx. 2.5V and 0.25 V corresponds to approx. 40°C.
3.
Relationship between heat roller surface temperature and fuser lamp operation.
14. FUSER UNIT
4.
Temperature control at heat roller ends
During multicopying, the temperature at each end (no paper-contact area) of the heat roller normally tends
to rise higher than the controlled temperature of the paper-contact area. Therefore, the circuit is designed so
that if the temperature in the no paper-contact area rises to 240°C, the second thermistor detects this,
causing the heater to be turned OFF immediately regardless of the temperature in the paper-contact area.
Temperature
(AR-650)
(AR-800)
Heater lamp state
Less than 200°C
ON
200°C
Maintains previous status
More than 200°C
OFF
Temperature
Fusing control
200°C or above
Heater lamp OFF
170~200°C
Heater lamp ON
Normal copy speed
160~170°C
Copying is continued at a
lower speed.
160°C or below
Copying is interrupted and
the machine is reset to the
ready state.
˚C
Copying
Copying
Waiting
Heater lamp
ON
Copy speed
OFF
0
0
0
80
65
80 65
0
80
65
0
OFF
ON
ON
ON
ON ON
ON
ON
Warm up
Standby(200 )
200
170
160
ON
ON
Standby
(200 )
Reference
Copying (200°C)
Heat roller
temperature
distribution
Heater lamp
ON
OFF
OFF
OFF
ON
ON
ON
ON
Warm-up
Standby (200°C)
C
200
OFF
OFF
ON
OFF
If the counter has a value 10 or greater (11 for example), the BC-RAM or the data in it have been
destroyed by charger leakage, etc. In this case, check the guide bias, high-voltage transformers,
charger wires, etc. for any defects. Also, all the data inside BC-RAM needs to be rechecked.
