Development - Xerox Phaser 6500 Service Manual

Development

Phaser 6500/WorkCentre 6505 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 motors and the developer motor
in the Main Drive Assembly. The toner is consumed according to the print count
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 is agitated by the auger, and supplied to the
magnet roller. 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 is attracted to the magnetic roller.
Toner Cartridge
Agitator
Auger
The magnet roller is covered by a thin semi-conductive sleeve. A developing bias
voltage is supplied to the sleeve from the High Voltage Power Supply (HVPS). The
developing bias voltage is negative DC voltage combined with AC voltage. The DC
voltage holds the magnet roller at a constant negative voltage against the
photoreceptor layer of the drum. Therefore, at the area where the negative electric
charge on the drum surface does not decrease, the potential is lower than that of
the magnet roller, while the potential is higher than that of the magnet roller at
the area where the negative charge on the drum surface decreases.
The AC voltage waveform releases the developer on the magnet roll so that the
toner moves to the drum. Thus, only the portions of the drum surface where the
negative charge has decreased below that of the magnet roll (electrostatic latent
image) attract toner to form an image on the drum.
Once the toner is deposited on the drum, the potential and the toner-attracting
force of the corresponding portion decreases because the increase of negative
charge lowers the potential at that portion.
Xerox Internal Use Only
Theory of Operation
: Negative Electric Charge
: Positive Electric Charge
: Toner
: Carrier
Paddle
Trimmer Rod
Drum
Magnet Roller
HVPS
Auger
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