3: Operation
Colorwriter LSR 2000 Printer
Service Guide
3-53
Generation of voltages applied to the
separation charging unit
Separation AC voltage is applied to the separation charging unit for
prevention of image distortion only when a low temperature/low
humidity environment is sensed by the environment detection
function. Separation DC voltage is usually applied to the fixing
upper roller and the separation charging unit during PRINT period.
The high-voltage control IC (IC1003) on the high-voltage power
supply PCB sets the separation dc voltage drive signal (/HVSEP) to
“L” and generates the voltage in the separation DC voltage
generation circuit in the high-voltage power supply PCB. The
separation DC voltage is input once to the separation HVT PCB,
and applied to the fixing upper roller and the separation charging
unit. On the other hand, when the separation ac voltage drive signal
(/HVSEPAC) input from the mechanical controller goes “L,” the
separation AC voltage generation circuit in the separation HVT
PCB generates the separation AC voltage, and applies it to the
separation charging unit upon superimposing it onto the separation
DC voltage.
Even if a low temperature/humidity environment is sensed, the
separation charging unit can be turned OFF from the density
adjustment panel.