Xerox PHASER 7500, Service Manual

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2-14 Phaser 7500 Printer Service Manual
Theory of Operation
Cleaning (Drum/ BCR)
Excess toner on the Drum surface and the BCR is removed, and the potential on
the Drum surface is discharged.
• Discharging the Drum - A Drum that has gone through the "Primary Transfer"
process is discharged by exposure of light from the Erase Lamp.
• Cleaning a Drum - Toner that was not transferred to the belt during the
"Primary Transfer" process remains on the Drum surface. Because this toner
will interfere with the subsequent processes if allowed to remain on the Drum
surface, the Cleaning Blade that is in contact with the Drum scrapes off the
remaining toner, which is then transported by the Drum Waste Toner Collector
into the Waste Toner Bottle.
• Cleaning the BCR - The Cleaning Roll, which is made from spongy material,
contacts the BCR surface to remove the remaining External Additive (the
whitish transparent powder on the toner surface) and returns it to the Drum.
The External Additive that was returned to the Drum, along with any
remaining toner on the Drum, will be scraped off and removed by the
Cleaning Blade during the Drum Cleaning process.
Positive Electric Charge
Negative Electric Charge
Toner
Toner External Additive
Erase Lamp (LED)
Conductor
Photoconductor
Cleaning Roll
BCR
Cleaning Blade
Drum
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