Canon iR2318 series, Service Manual, Page: 157 / 308

Chapter 6
6-5
- At the end of printing
To prevent fogging of the drum, the developing DC bias is held higher than usual except during image formation.
To prevent the toner remaining on the photosensitive drum from sticking to the transfer charging roller, the transfer roller bias which is lower than that applied
during printing the is applied at the prescribed timing.
F-6-5
[1] Time until post-rotation
6.4 Driving and Controlling the High-Voltage System
6.4.1 Outline
0020-4095
The voltage generated by superimposing the DC voltage over the AC voltage is applied to the primary charging roller and developing cylinder, and a positive or
negative DC voltage is applied to the transfer charging roller according to the instruction of the CPU on the DC controller PCB.
The primary DC bias and developing DC bias are changed according to the image density information sent from the image processor PCB, thus adjusting the image
density.
A negative DC voltage is applied to the electrostatic discharge needle and fixing film.
F-6-6
Cleaning bias
[1]
PRINT LSTR STBY
Main motor
(M204)
Scanner motor
(M203)
Primary charging
AC bias
Primary charging
DC bias
Developing
AC bias
Developing
DC bias
Transfer bias
Fixing film bias
Static eliminator
bias
ASIC
CPU
Primary bias
circuit
Fixing film bias
circuit
Transfer bias circuit
Remaining toner
level detection circuit
Static eliminator
bias circuit
JP3/JP4
JP9/JP10
JP7/JP8 Developing bias
circuit
JP1/JP2
High-voltage power
supply PCB
DC controller
PCB
J214 J100
Tr3
JP5/JP6