6 ] Copy Process; Copy Process Diagram; Image Forming Process; Detailed Description Of Image Forming Process - Sharp Z-21 Service Manual

[6] COPY PROCESS
This model uses an OPC. (photoconductor) drum to form an image
on it.

1. Copy process diagram

Copy lamp
Cleaning blade
Waste toner collection
Paper exit

2. Image forming process

Brief description of image forming process:
A charge is applied on the entire drum surface, onto which the
image of the original is projected by means of the copy lamp
selfoc. Where the light strikes the drum, the charge dissipates and
an electrostatic latent image is formed on the drum surface. Toner
is attracted to the electrostaticly charged areas of the drum to
form a visible image.
Step 1. Photoelectrical discharge (residual charge on the drum sur-
face is neutralized)
Step 2. Change
(a latent image is formed on the drum surface)
Step 3. Exposure
Step 4. Developing (the latent image on the drum is developed into
a visible image with toner)
Step 5. Transfer (the visible image, toner image, on the drum sur-
face is transferred onto the copy paper)
Step 6. The potential on the transfer paper is neutralized, and the
paper is separated.
Step 7. Cleaning (residual toner on the drum surface is collected by
the cleaning blade)
Step 8. Photoelectric discharge (residual charge on the drum sur-
face is neutralized)
Main corona
Charge
Discharge
Cleaning
Fusing Separation
Heat roller Separator pin
Heater lamp
Original
SELFOC lens
Exposure
Developing
Drum
Transfer
Transfer corona
3. Detailed description of image forming
process
Step 1. Photoelectric discharge
Prior to charging, light from the copy lamp is projected over the drum
surface to reduce electrical resistance of the OPC layer and neutral-
ize any residual charge.
As the electrical resistance is decreased, the positive charge in the
aluminum layer neutralizes the negative charge in the OPC layer.
– 9 –
Toner
Developer
Resist roller
Paper stoper
Sync with
Paper feed
drum
Copy lamp