Canon imageRUNNER 2525 Series, Service Manual, Page: 67 / 402

Cleaning blade in contact with the photosensitive drum scrapes off the residual toner on its surface without being transferred to
a paper. The residual toner scraped off by the cleaning blade is fed from the toner ejection part into the waste toner box by the
waste toner feed screw. The primary charging roller is cleaned by the brush roller in contact with it.
Photosensitive drum
Cleaning Blade
Primary charging roller
Waste toner feed screw
M 1
[1]
Toner ejection part
Brush roller
DC Controller PCB
No. Part name
M1 Main motor
[1] Main motor drive signal
● Primary Charging Bias Control
The machine is directly charged by the charging roller. DC bias and AC bias that stabilized the charge is applied to the primary
charging roller.
Photosensitive drum
[2]
Environment sensor
[1]
Primary charging roller
HVT PCB
Primary DC bias
control circuit
Primary AC bias
control circuit
DC Controller PCB
No. Part name
[1] Primary charging bias control signal
[2] Environment sensor detection signal
● Constant voltage control of DC bias and AC bias
The DC bias and AC bias control circuits on the DC controller PCB control the DC bias and AC bias applied to the primary charging
roller to keep their voltage at the fixed level.
2. Technical Explanation
57