Xerox PHASER 6130, Service Manual

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2-8 Phaser 6130 Color Laser Printer Service Manual
Theory of Operation
The Magnet Roller is covered by a thin semi-conductive sleeve over the
surface. The Developer Bias voltage is supplied to this semiconductor sleeve
from the High-Voltage Power Supply (HVPS). Developer Bias is negative
Direct Current (DC) voltage combined with Alternating Current (AC) voltage.
The Magnet Roller is kept at constant negative voltage against the
photoreceptor layer of the drum by DC voltage. Therefore, at the area on the
drum surface where the negative electric charge does not decrease, potential
is lower than the Magnet Roller, while the potential is higher than the Magnet
Roller at the area where the negative charge on the drum surface decreases.
The AC voltage shakes the Developer on the Magnet Roller surface, causing
the toner to transfer to the drum.
Thus, the negatively charged toner is attracted only to the area on the drum
surface (electrostatic latent image) where the negative charge is lower than
the charge on the Magnet Roller, forming the toner image on the drum. Once
the toner adheres to the drum, the negative charge of the toner-bearing
location increases, which decreases the potential and the toner-attracting
force.
Drum Surface
Toner
Image
Electric Potential
on Drum
Developing
Bias
-V
0
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