Sharp AR-6020V Service Manual page 122

B. Operational descriptions
The OPC drum surface is negatively charged by the main charger,
then laser image beams are radiated to the OPC drum surface by
the laser (writing) unit to form electrostatic latent images.
1) The OPC drum surface is negatively charged by the main
charger.
High voltage unit
CTL
CGL
Aluminum
layer
The main charger grid is provided with the screen grid. The
OPC drum is charged at a voltage virtually same as the volt-
age applied to the screen grid.
2) LED lights are radiated to the OPC drum surface by the laser
unit to form latent electrostatic images.
Laser beam
OPC drum
When LED lights are radiated to the OPC drum CGL, negative
and positive charges are generated.
Positive charges generated in CGL are attracted to the nega-
tive charges on the OPC drum surface. On the other hand,
negative charges are attracted to positive charges in the alumi-
num layer of the OPC drum.
Therefore, positive charges and negative charges are bal-
anced out on the OPC drum and in the aluminum layer, reduc-
ing positive and negative charges to decrease the OPC drum
surface voltage.
Electric charges remain at a position where laser beam are not
radiated.
As a result, latent electrostatic images are formed on the OPC
drum surface.
Main corona unit
Screen grid
OPC drum
OPC drum
CTL
CGL
layer
Aluminum
AR-6020V OPERATIONAL DESCRIPTIONS 11 – 15
3) After transfer operation, remaining toner is removed by the
cleaning blade.
Residual toner removed from the OPC drum surface is trans-
ported to the waste toner box section in the toner cartridge by
the waste toner transport screw.
4) The whole surface of the OPC drum is discharged.
Laser beam
CLT
CGL
layer
Aluminum
After completion of the job, laser beams are radiated onto al
the surface of the OPC drum.
When laser beams are radiated onto the CGL of the OPC
drum, positive and negative charges are generated.
Positive charges generated in CGL are attracted to the nega-
tive charges on the OPC drum surface. On the other hand,
negative charges are attracted to positive charges in the alumi-
num layer of the OPC drum.
Therefore, positive and negative charges are balanced out on
the OPC drum surface and in the aluminum layer, reducing
positive and negative charged to decrease the surface voltage
of the OPC drum.
CLT
CGL
layer
Aluminum