25 July 1996FUSING AND PAPER EXIT
8.3 FUSING TEMPERATURE CONTROL
Detailed
Descriptions
A174D529.wmf
8.3.1 Fusing Circuit Operation
The fusing lamp is powered by the ac drive board and controlled by the main
board.
The ac drive board receives direct wall voltage ac power (not stepped down)
at T201 and T202. It also receives +24 volts at CN201-2. The ac power is
applied to the drive circuit, the fusing lamp, and the triac (TRC201). The dc
power drives PTC201 and RA201.
To turn on the fusing lamp, the main board drops CN102-A20 to LOW. This
activates the photocoupler (PTC201) which in turn energizes the drive circuit.
The drive circuit turns on the triac to complete the lamp circuit, thus turning
on the lamp.
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