Machine Configuration; Copy Processes Around The Drum And Belt - Ricoh A66 Service Manual

2. MACHINE CONFIGURATION

2.1 COPY PROCESSES AROUND THE DRUM AND BELT

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1. Drum Charge
In the dark, the charge corona unit gives a negative charge to the
organic photoconductive (OPC) drum. The grid plate ensures that corona
charge is applied uniformly. The charge remains on the surface of the
drum because the OPC layer has a high electrical resistance in the dark.
The amount of negative charge on the drum is proportional to the
negative voltage applied to the drum charge corona wire and casing.
2. Laser Exposure
A laser beam is reflected onto the drum by the polygon and drum
mirrors. This forms an electrical latent image on the drum surface. The
amount of charge remaining as a latent image on the drum depends on
the laser beam intensity.
3. Drum Potential Detection
The drum potential sensor detects the strength of the electric field on the
charged drum. The sensor output is one of the signals used in process
control.
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MACHINE CONFIGURATION
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A166/A187/A189
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