Sharp AL-1600 Service Manual page 19

Operation cycle
Paper exit roller
Paper exit
Main charger
High voltage power
Laser beam
Laser scanning unit
B. Outline of print process
The printer section of this machine employs the laser print system
where print images are formed by the laser beams on the OPC drum.
A high voltage (corona) is applied from the main charger to the OPC
drum to charge the OPC drum.
Laser beams are radiated to the charged OPC drum to form electrical
images on the OPC drum. (Exposure)
(At that time, the print image on the OPC drum cannot be seen: latent
electrostatic image)
By the potential difference between the unexposed area and the
latent electrostatic images, toner ia attracted only to the im-
ages.(Developing)
(At that time, the print image formed by toner on the OPC drum can
be seen. Visible images)
The toner image on the OPC drum is transferred on the print paper
by the transfer corona (voltage).
After that, the print paper with the toner image on it is subject to heat
and pressure in the fusing section to fuse the image on the paper.
This machine employs the following organic photoconductor (OPC)
drum.
An OPC drum is used for the photoconductor.
(Structure of the OPC drum layers)
Heat roller
Fusing
Cleaning blade
Cleaning
Waste toner box
Charging
Exposure
High voltage
Developing unit
power
Toner hopper
OPC layer
(20microns thick)
Pigment layer (0.2
to 0.3 microns thick)
Aluminium drum
Separation
Transfer
Transfer
Synchronization
with drum
Developing
Developer
Toner
Cassette paper
feed
C. Actual print process
(1) Charging
A high voltage is applied to the main charger, and negative charges
are discharged to the OPC drum. A screen grid is provided between
the main charger and the OPC drum, and negative charges are
uniformly charged on the OPC drum surface.
Positive charges are attracted by the negative electrode on the OPC
drum surface and excited in the aluminum layer in the OPC drum.
DC5.5KV
6 – 3
AL-1610
Separation charger High voltage power
Transfer charger High voltage power
Resist roller
Manual paper
feed
(-525V/-400V)