Sharp Z-87 Service Manual page 40

7. Drum cartridge
General description:
The drum cartridge consists of an OPC drum, main corona, remover
tape, cleaning blade, and auger roller. A small tab on the rear frame
side of the cartridge is used for resetting the mechanical drum
counter. This is a one-time only action and will not reset the counter
again though the drum cartridge is removed and reinserted.
Inside the drum cartridge the cleaner blade is always in contact with
the drum. During the copy process the residual toner is removed from
the drum surface by the blade. The auger roller transports the used
toner to the toner collection container located on the front of the TD
cartridge.
The remover tape located on the rear frame side of the drum
cartridge mechanically strips the paper from the drum and guides it to
the separation roller. Due to the copy paper not contacting the drum
in this area there is a void of less than 9 mm along the rear frame
side of the copy.
NOTE: The drum cartridge is set to factory specifications and is not
adjustable in the field. If a problem is suspected replace the
entire cartridge.
8. TD cartridge
General description:
The TD cartridge applies toner to the electrostatically charged areas
of the drum, and develops the latent image on the drum. The mag-
netic roller is a rotating aluminum sleeve. At the center of the MG
roller are stationary magnets. These magnets hold and direct the
developer. The developer is composed of very fine magnetic filings
and is used to transport the Toner from the developer to the drum.
As the MG roller rotates, it carries Developer and Toner. The mag-
netic field around the MG roller forms the Developer into a "Magnetic
Brush". The height of the magnetic brush is determined by the doctor
blade. The angle of the brush is determined by the position of the
magnets in the MG roller.
The auger roller keeps the mixture of Toner and Developer agitated
and uniformly mixed. Since the developer is used as a carrier of
toner, the developer is not used up, and the volume of developer
remains constant. As the toner is pulled out of the developer, the ratio
of toner to developer decreases. The toner sensor measures this
ratio, and feed back this information to the main PWB which will
energize the toner motor (TM) when additional toner is required. The
toner motor is mounted on the rear frame of the copier.
The toner sensor and bias connect to the main PWB by a four pin
connector located on the rear side of the unit.
The bias voltage is used to prevent background by applying a counter
balancing charge to the developer.
NOTE: The TD cartridge is set to factory specifications and is not
adjustable in the field. If a problem is suspected replace the
entire cartridge.
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