Development - Xerox Phaser 6128MFP Service Manual

Development

Phaser 6128MFP Service Manual
Toner is electrically attached to the invisible electrostatic latent image on the drum
surface to form the visible toner image on the drum.
The toner in the Toner Cartridge is agitated by the built-in agitator and fed into
the developer. The augers are driven by the Toner Motor and the developer motor
in the Main Drive. The toner to be consumed according to the print count is
calculated and fed into the developer. This process, called toner dispensation, is
controlled by two processes: pixel count dispense control (PCDC) and automatic
density control (ADC).
The toner fed into the developer and the carrier in the developer are agitated by
the auger, and supplied to the magnet roller arranged in the drum surface area.
The toner and carrier are charged by friction due to agitation (toner in negative,
carrier in positive), and they are attracted electrically. A uniform layer is formed by
the trimmer bar as the carrier magnetic substance is attracted to the magnetic
roller.
Toner Cartridge
Agitator
Auger
The magnet roller is covered by a thin semi-conductive sleeve. The developer bias
voltage is supplied to the sleeve by the HVPS. Developer bias is negative DC
voltage combined with 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.
Theory of Operation
: Negative Electric Charge
: Positive Electric Charge
: Toner
: Carrier
Paddle
Trimmer Rod
Drum
Magnet Roller
HVPS
Auger
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