D. High-Voltage Power Supply Circuit - Canon LBP-2000 Service Manual

CHAPTER 2

D. High-Voltage Power Supply Circuit

1. Outline
Video
controller PCB
J5
-20
/PRNT
The high-voltage power supply circuit is mounted on the DC controller PCB, and is used to apply
a voltage (generated by combining DC and AC voltages) to the primary charging roller and the
developing cylinder in response to commands from the CPU and according to the print signal (/
PRNT) from the video controller PCB; it applies a positive or negative DC voltage to the transfer
charging roller.
It also varies the primary DC bias and the developing DC bias to adjust the image density based
on the image density data from the video controller PCB.
2 - 18
DC controller PCB
ASIC
J104
-20
CPU
Figure 2-2-7
High-voltage power
supply PCB
Primary
bias circuit
Transfer
bias circuit
Developing
bias circuit
Toner level
detection circuit
TB401/TB402
Pr
T403
Tr
TB403/TB404
Dv
TB405/TB406
Ant