Drum Maintenance System - Xerox Phaser 8400 Service Manual

Drum Maintenance System

The drum maintenance system creates a thin intermediate liquid transfer surface, a
layer of silicone oil, on the surface of the drum prior to printing. The oil keeps the ink
from sticking to the drum's surface and facilitates its transfer to the sheet of paper or
transparency film. The oil is contained in a porous foam roller.
Prior to each print, a cam, driven by the process motor, raises the pivot plate, which
raises the oil roller against the rotating drum. A compliant wiper blade, also raised by
the same cam, assures that the oil film is smooth and even across the drum's surface.
The process drive rotates in one direction, which rotates the drum maintenance
camshaft, and raises the drum maintenance system to the drum. The process drive
rotates in the opposite direction to lower the drum maintenance system. The blade
removes oil that is drained back into the maintenance kit drawer, through a felt filter,
to the oil roller for reuse. As the drum completes one rotation, the rotating cam lowers
the oil roller and then a moment later, lowers the blade.
The drum has a floating deadband, which is the narrow section of the drum containing
excess oil and other debris. The oil bar is left on the drum surface when the blade is
removed from the drum. This oil bar location is controlled to keep it outside of the
print area.
An EEPROM chip, built-in to the maintenance kit, stores the number of oiling cycles
performed by the drum maintenance system. The EEPROM stores the number of
prints remaining to track consumable life. At printer startup, four oiling cycles are
performed to condition the drum.
Drum maintenance
camshaft
Service Manual
Drum maintenance
pivot plate
Maintenance roller
Drum
Oil on drum
Blade
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