Engine power supply The power supply consists of the fuser-control circuit, the high-voltage circuit, and the low-voltage circuit. The fuser-control and high-voltage circuits control the temperature of the fuser and generate high- voltage according to signals from the DC controller PCA. The low-voltage circuit generates the DC voltages that other components in the product use (for example the DC controller PCA, the motors, and fans). Fuser-control circuit The fuser-control circuit controls the fuser components. The two fuser heaters provide the high temperatures that cause the toner to permanently bond to the media. The fuser thermistor monitors the fuser temperatures.
The thermal switch detects abnormally high fuser temperatures and interrupts the supply of voltage to the fuser if the temperature is too high. Figure 1-10 Fuser control TH2 TP1 H1 TH1 Fuser control FUSER HEATER DRIVE signal Fuser sleeve Fuser heater drive circuit Relay Pressure roller FUSER HEATER TEMPERATURE signal DC controller ENWW Engine-control system 15 Fuser heater safety circuit CPU