Brother HL-3450CN Series, Service Manual

Page: 64 / 365

HL-3450CN SERVICE MANUAL
4-11
(2) Variation of OPC Belt Potential (See Fig.4-10.)
i) The OPC belt is initially biased to -CBV (V).
ii) The OPC belt surface is evenly charged to V
0
(V) in the charging process.
iii) The potential of the exposure part of the OPC belt is reduced to -VR (V) as it is
exposed to the laser beam in the process of exposing, and an electrostatic latent
image is formed on the OPC belt as the result.
iv) Negatively charged toner is moved onto the exposed part of the OPC belt in the
development process due to the difference of potential between -VR (V) and -DBV
(V), and a visible toner image is formed as the result.
v) Negatively charged toner on the OPC belt moves to the transfer drum surface in the
transfer process because the GND potential of the transfer drum is greater than -
VR (V) of the OPC belt.
vi) The OPC belt is discharged by the erase lamp.
2 3 4
5
OV
Transfer Drum
Toner
- CBV
OPC Belt
CBV
- V
O
- V
R
DBV
Charger
CHV
DBV
Dev. roller
Charging Process
Exposing Process
Developing Process
Transfering Process
Cleaning (Erase)
Power Supply for OPC Belt Bias
Power Supply for Charging
Power Supply for Dev. Roller Bias
Remain voltage on the OPC Belt
Process
GND
Toner
1
1
2
3
4
5
CBV
CHV
DBV
- VR
Fig. 4-10