User Guide

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 printer use (for example the dc controller PCA, the motors,
and fans).
Figure 5-2 Power-supply block diagram
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.
110 5 Theory of operation