Heater Control Circuit; Temperature Detection Unit - Toshiba 1550 Service Manual

12.4

Heater Control Circuit

(1) Temperature detection unit

In order to control the temperature of the heat roller, the temperature detector unit detects the heat-
roller temperature with a thermistor and ON/OFF controls the heater lamp. Heat roller surface tem-
perature 180°C (thermistor resistance value: 7.4 KΩ approx.)
Reference
Relationship between heat roller surface temperature and thermistor
resistance value.
Temperature
Less than 180°C
180°C
More than 180°C
Warming up
°C
180
Heat roller
temperature
distribution
Mar. 1998 © TOSHIBA
Thermistor resistance
More than 7.4 KΩ
7.4KΩ
Less than 7.4 KΩ
Ready (180°C)
Heater lamp
OFF ON
ON
Heater lamp state
ON
Maintains previous state
OFF
OFF ON OFF ON OFF
12 - 9
During copying (180°C)
ON ON
1550/1560 FUSER