Developing Unit - Canon imageRUNNER 2545 Series Service Manual

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Technology > Image Formation System > Controls > Developing Unit

■ Developing Unit

The developing unit mainly consists of the developing cylinder, developing blade, toner
agitation plate, and toner feed screw, and driven by the main motor (M1) and developing
cylinder clutch (CL3).
The toner supplied from the toner cartridge is fed into the drum unit by the toner feed screw
and toner agitation plate. The toner presence/absence in the drum unit is detected by the
developing unit toner sensor (TS1) which is a magnetic permeability sensor.
Toner agitation plate
Developing Blade
TS1
CL 3
M 1
[3] [2]
DC Controller PCB
TS1 Developing unit toner sensor
CL3 Developing cylinder clutch
M1 Main motor
[1] Developing cylinder clutch drive signal
[2] Main motor drive signal
[3] Developing unit toner sensor detection signal
2 Technology > Image Formation System > Controls > Developing Unit
Toner feed screw
Developing cylinder
[1]
F-2-63
● Developing Bias Control
The DC bias and AC bias are applied to the developing cylinder.
Density Setting
Main Controller PCB
Environment sensor
HVT PCB
[3] [2]
Developing AC bias
control circuit
DC Controller PCB
[1] Developing bias control signal
[2] Environment sensor detection signal
[3] Density setting 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 developing cylinder to keep their voltage at the fixed level.
● DC bias switch control
The DC bias output varies according to the environment or density setting detected by the
environment sensor (HU1).
Photosensitive drum
Developing cylinder
[1]
Developing DC bias
control circuit
F-2-64
2-39
2-39