Toshiba e-studio 151, Service Manual

Page: 33 / 176

e-STUDIO162/162D/151/151D COPY PROCESS 6 - 2
2. Outline of print process
This printer is a non-impact printer that uses a semiconductor laser
and electrostatic print process. This printer uses an OPC (Organic
Photo Conductor) for its photoconductive material.
First, voltage from the main corona unit charges the drum surface and
a latent image is formed on the drum surface using a laser beam. This
latent image forms a visible image on the drum surface when toner is
applied. The toner image is then transferred onto the print paper by the
transfer corona and fused on the print paper in the fusing section with
a combination of heat and pressure.
Step-1: Charge
Step-2: Exposure
*
Latent image is formed on the drum.
Step-3: Developing
Latent image formed on the drum is then changed into visible
image with toner.
Step-4: Transfer
The visible image (toner image) on the drum is transferred
onto the print paper.
Step-5: Cleaning
Residual toner on the drum surface is removed and collected
by the cleaning blade.
Step-6: Optical discharge
Residual charge on the drum surface is removed, by
semiconductor laser beam.
3. Actual print process
Step-1: DC charge
A uniform negative charge is applied over the OPC drum surface by
the main charging unit. Stable potential is maintained by means of the
Scorotron charger.
Positive charges are generated in the aluminum layer.
Step-2: Exposure (laser beam, lens)
A Laser beam is generated from the semiconductor laser and
controlled by the print pattern signal. The laser writes onto the OPC
drum surface through the polygon mirrors and lens. The resistance of
the OPC layer decreases for an area exposed by the laser beam
(corresponding to the print pattern signal). The beam neutralizes the
negative charge. An electrostatic latent image is formed on the drum
surface.
About
DC5.5KV
( 580V/ 400V)
OPC layer
Pigment
layer
Aluminum
drum
OPC layer
Pigment
layer
Aluminum
layer
Drum surface charge
after the exposure
Non-image area Image area
Semiconductor laser
Exposure
(semiconductor laser)
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