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June 2004 © TOSHIBA TEC e-STUDIO200L/202L/230/232/280/282 COPY PROCESS
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2) Charging
Charging is the process to apply charge evenly on the drum surface.
The needle electrode produces negative corona discharge is controlled by the grid, allowing the
drum surface to be evenly charged with the negative potential.
The surface potential on the drum is determined by the grid potential and is controlled to a certain
value by the grid control circuit.
Fig. 3-4
3) Data reading (scanning)
Data reading is the process of illuminating the original with light and converting the reflected light
into electrical signals.
The light reflected from the original is directed to the charge coupled device (CCD) and this optical
image information is converted into electrical signals (image signals), which are then transmitted to
the image processing section.
Fig. 3-5
Fig. 3-6
Main charger
Drum rotation
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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