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 saturated 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
also directs excess oil back 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.
An NVRAM chip, built-in to the maintenance kit, stores the number of oiling cycles
performed by the Drum Maintenance System. At printer startup, four oiling cycles are
performed to condition the drum.
Drum maintenance
camshaft
Drum maintenance
pivot plate
Theory of Operation
Drum
Oil on drum
Blade
Maintenance roller
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