Temperature Detection By The Thermistor - Toshiba DP1600 Service Manual

14.6.2 Temperature detection by the thermistor

* The detection circuits for heater thermistors 1 and 2 are equal to each other. Here, heater thermistor 1
is described.
Heater
thermistor 1
• The input voltage is obtained by dividing the +5V among R342, Heater thermistor 1 and R337.
• The surface temperature of the heat roller varies.
• The resistance of the heater thermistor 1 changes.
• The input voltage changes.
• The input voltage is converted to digital data by the A/D converter and output to the register of the
system control GA. The CPU reads this value and detects a change in the data to judge if the heat roller
temperature is normal or abnormal.
December 2000 © TOSHIBA TEC
+5V +5V
R342
IC23
TH
A/D
converter
R337
SG
Fig. 14-6-2
14 - 9
IC34
ADCDO
System
control
GA
1600/2000/2500 FUSER UNIT/EXIT UNIT
IC66
CPU
14-06-02