Sharp Digital Copier Printer User Manual


 
b. Major parts functions and operations
1 Developing
roller
5 Toner seal 9 Discharge
brush
2 Doctor 6 Transfer
charger roller
10 Main charger
brush
3 Toner stirring
plate
7 Separation
electrode
11 Toner seal
4 Toner supply
roller
8 Phot conductor
drum
12 Discharge
(Earth) sheet
<1> Photoconductor drum unit
The photoconductor surface is charged and latent electrostatic im-
ages are formed, then visible images are formed with toner.
1) Photoconductor drum
Latent electrostatic images are formed and visible images are formed
with toner.
An OPC (Organic Photo Conductor) drum is used. The OPC drum
surface is negatively charged by the main charger brush.
When laser beams are radiated on the OPC drum, the electric resis-
tance at the radiated area is reduced to generate an electric charge
inside the OPC drum. As a result, the charges on the OPC drum are
removed. This process is used to form latent electrostatic images.
2) Main charger brush
The main charger brush charges the OPC drum surface. It is com-
posed of brush textures and of a roller shape.
A high voltage of AC 600V (P-P) is applied to DC-850V to charge the
brush.
The main charger brush is in contact with the OPC drum. By supply-
ing electric charges to the OPC drum, the OPC drum is charged to
about –850V.
3) Toner seal
The OPC drum has two toner seals. The toner seals are used to
prevent residual toner on the OPC drum from leaking outside.
<2> Developing unit
Visible images are formed with toner over the latent electrostatic
images formed on the OPC drum surface. Toner is filled in the
developing unit.
1) Developing roller
The developing roller is made of urethane and it has considerably
high electrical resistance. It is flexible and pressed onto the OPC
drum. Toner is attached to the latent electrostatic images on the OPC
drum to make visible images. A voltage of DC-310V/+200V is applied
to the developing roller. A voltage of –310V is applied when develop-
ing. A voltage of +220V is applied when cleaning.
2) Doctor
The doctor is pressed onto the developing roller. It adjust the toner
quantity on the developing roller surface.
The doctor is made of a conductive material.
3) Toner supply roller
The toner supply roller transports toner to the developing roller.
4) Toner stirring plate
The toner stirring plate stirs toner in the developing unit to transport
toner to the developing roller smoothly.
5) Toner seal
The toner seal prevents toner from leaking outside the developing
unit.
6) Discharge (Earth) sheet
The discharge sheet maintains the developing roller surface potential
at a constant level.
<3> Transfer charger roller
The transfer charger roller is made of urethane and its electrical
resistance is considerably high. It is flexible and pressed onto the
OPC drum.
A high voltage of AC600V (P-P) is applied to DC +3500V.
Paper transported from the paper feed section is charged positively
and negatively charged toner on the OPC drum are transferred onto
the paper.
During cleaning, a voltage of –850V is applied.
<4> Separation electrode
The separation electrode is connected to the drum earth. This dis-
charges paper charged positively in the transfer section to reduce
potential difference with the OPC drum, reducing electrostatic attrac-
tion power between paper and the OPC drum, facilitating paper
separation.
<5> High voltage unit
The high voltage is made by the invertor system, and is supplied to
the main charger unit, the transfer unit, and the developing roller.
3)
4)
12)
2)
5)
6)7)
8)
9)
10)
11)
1)
OPC layer
CTL
(Charge Transfer Layer)
CGL
(Charge Generation Layer)
Aluminum layer
1 – 20