Lexmark X862de Service Manual page 52

7500-432, -632, and -832
The charge roll is a conductive roll that is positioned slightly above the surface of the drum. The HVPS supplies
the charge roll with two voltages; a negative DC charge voltage and an AC discharge voltage that is used for
electrically cleaning the drum.
Photoconductive
Surface
Conductive Tube
Exposure
The Printhead generates a beam of laser light. Image data received from the RIP card assembly modulates this
beam, turning it on and off according to image information that is received from the host computer and software.
Through the use of a series of rotating and stationary mirrors within the Printhead, the beam scans the negative
charged drum surface. Whenever the print controller sends a command to print a black pixel, the laser switches
on long enough to shine onto the drum at a single pixel point. That point is now discharged and slightly less
negative than the surrounding negative charge. The less negative areas are considered positive. This
discharge/no discharge process creates an invisible, electrostatic image on the surface of the drum. This image
is called a latent image.
1-28
MFP Service Manual
Charge roll
(-VDC)
DRUM
Ground
HVPS
(-VDC)
Ground
Drum Surface
Drum Surface
Image
Voltage
0V
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-VDC value