MX-1800N (serv.man29). Details of each Section - i Photoconductor Section - Sharp Copying Equipment Service Manual (repair manual). Page 2

MX-1800N  PHOTOCONDUCTOR SECTION  i – 2

The OPC drum surface is negatively charged by the main charger.
The laser beam images are radiated to the OPC drum surface by
the laser (writing) unit to form latent electrostatic images.
1) The OPC drum surface is negatively charged by the main

charger.

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

(writing) unit to form latent electrostatic images.

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 LED lights are not
radiated.
As a result, latent electrostatic images are formed on the OPC
drum surface.

3)

After transfer operation, remaining toner is removed by the
cleaning blade.
Toner removed from the OPC drum surface is transported to
the waste toner section by the waste toner transport screw.

4)

The whole surface of the OPC drum is discharged.

By radiating the discharge lamp light to the discharge lens,
light is radiated through the lens to the OPC drum surface.
When the discharge lamp light is radiated to the OPC drum
CGL, 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.

DMCL

Drum motor (Color)

Color photoconductor drive

DMBK

Drum motor (Black)

Black photoconductor drive

DL

Discharge lamp (Y, M, C, BK)

Light is passed to the discharge lens to drive the OPC drum surface.

MC

Main charge (Y, M, C, K)

The OPC drum surface is charged negatively.

GB

Grid (Y, M, C, K)

The OPC drum surface potential is controlled. 

1

OPC drum (Y, M, C, K)

Latent electrostatic images are formed. 

2

Cleaning blade

Residual toner is cleaned and removed from the OPC drum surface.

Aluminum

layer

OPC drum

CTL

CGL

High voltage unit

Main corona unit

Screen grid

LED lights

Aluminum
layer

OPC drum

OPC drum

CGL
CTL

Lens

CGL

CGL

Aluminum
layer

Aluminum
layer

CTL

CTL