Fuser temperature control The fuser temperature control detects the temperature of the fuser heater surface, and then controls the FUSER HEATER DRIVE (FSRD1) signal to the fuser heater until the fuser heater temperature reaches the target temperature. The DC controller controls the FSRD1 signal by monitoring the detected fuser heater temperature—using the thermistor (TH3)—and then holds the heater at the target temperature. Figure 1-11 Fuser temperature control AC input Fuser control DC controller CPU /FSRARI TH1 TH2 H1 TP1 J128 1 2 16 Chapter 1 Theory of operation ENWW Zero crossing circuit +24VC Relay Relay (RL102) (RL101) Current detection circuit Fuser heater drive circuit JP1001 100V:
Open 200V: Close /RLD FSRSAFE Fuser heater safety circuit CURRMS detection circuit FSRD1 FSRTH2 JP1001 100V: Open 200V: Close /AC200 +3.3V /HITMP Q704 Zero crossing circuit