Canon Laser Shot LBP-5100, Service Manual

Page: 48 / 162

Chapter 2
2-14
F-2-19
2.4.2.3 Generation of the Primary Charging Bias
0010-6082
LBP5000 / LBP5100
The primary charging bias (PRI) is used to charge the surface of the photosensitive drum to a uniform negative potential in preparation for image formation.
The machine's primary charging bias is a negative DC bias generated by the primary charging high voltage generation circuit found on the high-voltage power
supply PCB. The high-voltage power supply PCB applies the primary charging bias it has generated to the primary charging roller of the individual cartridges at
specific timing.
The level of the primary charging bias varies according to the instructions from the DC controller PCB.
2.4.2.4 Generation of the Developing Bias
0010-6083
LBP5000 / LBP5100
The developing bias (DEV1, DEV2, DEV3, DEV4) is used to deposit toner over the latent (static) image formed on the surface of the photosensitive drum.
The developing bias is generated by the developing high-voltage generation circuit of the high-voltage power supply PCB, and may be a negative DC bias or AC
bias. The high-voltage power supply PCB applies a combination of these 2 types of biases to the developing cylinder of the cartridge at specific timing.
The level of the developing bias varies according to the instructions from the DC controller PCB.
2.4.2.5 Generation of the Transfer Bias
0010-6084
LBP5000 / LBP5100
The transfer bias (TR1, TR2, TR3, TR4) is used to move the toner image from the surface of the photosensitive drum to the print paper.
The transfer bias is generated by the transfer high-voltage generation circuit of the high-voltage power supply PCB, and may be a positive DC bias or negative DC
bias. The high-voltage power supply PCB applies these 2 types of transfer biases to the transfer roller according to the selected printing sequence.
The machine applies these biases in keeping with the following printing sequence:
TR1
TR2
TR3
TR4
DEV1
DEV2
DEV3
DEV4
PRI
TRS
FSR
DC controller
PCB
High-voltage
power supply PCB
Primary
charging
high-voltage
generation
circuit
Developing
high-voltage
generation
circuit
Sub high-voltage
power supply PCB
Transfer roller
ETB
Bk cartridge
C cartridge
M cartridge
Y cartridge
Fixing pressure
roller
ETB drive roller
Electrostatic eliminator unit
Transfer
high-voltage
generation
circuit
Fixing
high-voltage
generation
circuit
Electrostatic
eliminate
high-voltage
generation
circuit