Printronix L5535, Maintenance Manual

Page: 123 / 358

Precharging (Precleaning Charging)
II–123
Cleaning Section
In this section, the drum surface, containing excess toner from the previous
printing operation, is cleaned for the next printing cycle.
Precharging (Precleaning Charging)
After the paper is separated from the drum, some residual toner, carrier, and
paper dust remain on the drum. Such remaining toner should be positively
charged due to the friction with the carrier in the developing unit. In reality,
however, some toner particles are negatively charged. To avoid scratching
the drum, the remaining toner is removed electrically. The precharger forces
all of the toner particles to be positively charged.
Drum Cleaning
The remaining toner particles, which have been positively charged in the
precharging step, are removed by a negatively-biased semiconductive brush.
The toner on the brush then transfers to a recovery roller, to which a greater
negative DC bias is applied. A blade inside the cleaning unit then scrapes the
toner away from the recovery roller. Finally, the toner is carried away by a
screw conveyor and deposited in a waste toner bottle.
Precharger
Photoreceptor drum
Photoreceptor Drum
Precharger
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-
Blade
Recovery Roller Semiconductive Brush
Photoreceptor Drum
Screw Conveyor
Precharger
+
-
+
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