High-Voltage Control - Digital Equipment COLORWRITER LSR 2000 Service Manual

Colorwriter LSR 2000 Printer
Service Guide
3: Operation
Heater
DC bias
Figure 3-34 Fixing unit
This printer has a fixing unit installation detection function. When
the presence of a fixing unit is not detected, the DC controller
notifies the video controller.

High-voltage control

The high-voltage power supply of the printer is controlled by the
high-voltage control IC (IC1003). IC1003 communicates with the
mechanical controller and applies voltage to the primary charging
roller, developing cylinder, transfer drum, attraction roller, discharge
roller, separation charging unit, and fixing upper roller in response
to the commands from the mechanical controller.
The primary charging roller, developing cylinder, and separation
charging unit are charged with superimposed DC and AC voltages.
The transfer drum is charged with a positive DC voltage. The
attraction roller is charged with voltage with negative DC voltage
being superimposed onto the transfer voltage. The discharge roller is
charged with voltage with AC voltage being superimposed onto the
transfer voltage. The separation charging unit is normally charged
with only DC voltage and is charged with voltage with AC voltage
superimposed on DC voltage only in a low temperature/low
humidity environment. The fixing upper roller is charged with DC
voltage.
Cleaning belt
Upper roller
Paper
Lower roller
Toner
3-45