Xerox WorkCentre 385, Service Manual

Page: 139 / 184

Development Processing
12/98
7 - 5
WorkCentre 385
Development Processing
Charging
A negative voltage is applied to the surface of the OPC Drum. This is the first
step in creating an electrophotograph. The high voltage section of the Engine
Controller PBA supplies (-)1.4KV to the Charge Roller and transfers a charge of
approximately (-)800 V to the OPC Drum.
Exposure
LSU receives the transferred bitmap image data from the Engine PBA and turns
the LSU’s laser diode on and off, exposing the OPC Drum. If there is no data to
print the Laser Diode remains off and the OPC Drum is not exposed. Portions of
the OPC Drum exposed charged to approximately (-)50V by the laser beam
while unexposed portions charge to (-)800V. The image formed by the exposed
laser beam is invisible, and is called a latent image.
Development
Surface moves between the DEV Roller and the OPC Drum. Negatively
charged Toner is attracted to the high voltage(-50V) of the exposed portions of
the OPC Drum and is exposed more easily than the more negative (-800V)
surface voltage of unexposed areas of the OPC Drum, resulting in a latent
image.
OPC
CR
-800V
-1.4KV
OPC Surface
Unexposed Exposed Unexposed
-800V -800V
-50V
OPC
D/R S/R
-300V -500V
GND
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