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COPY PROCESS
3 - 3
(2) Charging
Charging is a process of applying a charge uniformly to the photoconductive drum surface.
The charger wire produces a negative corona discharge, which is controlled by the grid so that the
drum surface is uniformly charged with negative potential.
The surface potential on the drum is determined by the grid potential and controlled to a certain
value by the grid control circuit.
Fig. 3-4
(3) Scanning
Scanning is a process of exposing the original to the light and converting the reflection into electrical
signals.
The light reflected from the original is imported to the charge coupled device (CCD) and this optical
image information is converted into electrical signals (image signals), which are then sent to the
image processing section.
Fig. 3-5
Fig. 3-6
Main charger
Rotation of drum
Grid control circuitHigh-voltage
transformer
Image processing
section
CCD
(Example)
CCD light
receiving
amount
Value of image
signals to be
output
255
0
Difference between
"light " and "dark" is
divided into 256 steps.
Light
Dark
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