HP Pro 4300 C9H70UT C9H70UT#ABA manual Power supply, Fuser-control circuit

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.

Fuser heaters

Fuser thermal switch

Fuser thermistor

Figure 8. Fuser components

Q2431-90912 Chapter 5 Theory of operation 71