Sharp AM-900 Service Manual page 62

AM-900U
STEP 5 (Paper separation): The paper is separated from the OPC
drum.
OPC drum
Aluminum layer
(Drum base)
CGL
CTL
Fig. 16
There is an electrostatic force between the paper which is positively
charged in transfer operation and the OPC drum which is negatively
charged. The positive charge on the paper is released to the separa-
tion electrode, which is the same potential as the aluminum layer of
the OPC drum, to reduce the potential difference between the OPC
drum and the paper, reducing the electrostatic force.
This operation facilitates separation of the paper from the OPC drum.
Paper
Separation
electrode
Transfer roller
STEP 6 (Discharge): The drum surface is discharged to facilitate
cleaning of the drum surface. (The remaining
toner is easily collected by the main charger
roller.)
AC760V
Residual
(P-P)
toner
DC-950V
STEP 7 (Cleaning): Residual toner on the OPC drum is removed.
The main charger is a rotating brush roller.
The main charger removes residual toner from the OPC drum by its
rotating sweeping action and causes it to stick to the brush. The main
charger brush is in close contact with the mesh-type brush cleaning
plate which removes toner and paper dust from the main charger
brush mechanically.
3 – 15
Main charger
roller (brush)
OPC drum
Aluminum layer
(Drum base)
CGL
CTL
Fig. 17