C. Controlling the Fixing TemperatureThe surface temperature of the upper fixing roller is monitored by the main thermistor(TH1), and the output of the thermistor is sent to the microprocessor.Using the output, the microprocessor varies the main heater drive signal (MHRD)and the sub heater drive signal (SHRD) to control the fixing temperature.The rear of the copier’s upper fixing roller is equipped with a sub thermistor (TH2) tomonitor overheating.Figure 6-102Upper fixingrollerPS47Fixing unit delivery paper detect signal (FXDEL)Fixing assembly claw jam signal (FXCJS)Cleaning belt out precaution signal (CBOP)Fixing heater main thermistor (TH1)Main heater drive signal (MHRD)Sub heater drive signal (SHRD)DC controller PCBTPI SSRPS11PS52Cleaning beltguide plateMain thermistor (TH1)ThermalswitchLowerfixingrollerAC power supply AC driver PCBFixing heater sub thermistor (TH2)Subthermistor(TH2)COPYRIGHT © 1997 CANON INC. CANON NP6045 REV. 1 MAR. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)CHAPTER 6 FIXING SYSTEM6-3
