Lexmark C91 Series, Service Manual

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Service Manual
5055-xxx
Development unit
Toner forms the electrostatic image on the photosensitive drum
during exposure. The single component, non-magnetic toner and the
lusterless color toner are weather-resistant, and fade little under
ultraviolet rays. This is helpful in saving documents.
Toner in the hopper is agitated and supplied to the development roll
by the supply roll. A (conductive rubber) doctor blade is fitted to the
development roll. Toner enters between the development roll and
doctor blade by the rotating development roll and is negatively
charged, forming the electrostatic image on the photosensitive
drum. Toner attaches to the bright portion of the photosensitive drum
per the voltage of the development roll.
Transfer unit
Paper feeds electrostatically by the transfer belt and is carried to the
transfer unit which turn at the speed of the photodeveloper drum. A
charge roller applies a positive charge to the paper. The toner image
formed on the photoconductor drum is transferred to the paper from
the back side by the positive dc voltage applied to the transfer sheet,
which is in contact with the paper through the transfer belt.