- HP All-in-One Printer Manual

Q2431-90912 Chapter 5 Theory of operation 71
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 used by other components in the printer (for example the DC
controller PCA, the motors, and fans).
Figure 7. Power supply block diagram
Fuser-control circuit
The fuser-control circuit controls the fuser’s components. The two fuser heaters provide the high
temperatures which cause the toner to be permanently bonded to the media. The fuser
thermistor is used to monitor the fuser temperatures. The thermal switch detects abnormally high
fuser temperatures and interrupts the supply of voltage to the fuser if the temperature is
determined to be too high.
Figure 8. Fuser components
Fuser heaters
Fuser thermistor
Fuser thermal switch