Xerox Phaser 8560MFP Service Documentation page 288

Figure 12 Printhead Detail
The Printhead's jet stack is fabricated from a stack of chemically etched steel plates which are
brazed together to form the jet array. Channels formed by the stacked plates route ink past the
1236 individual, piezo-electric crystal-driven diaphragms, which force the ink in droplets out the
1236 corresponding nozzles. Looking at the Printhead face, the nozzles are arranged in 12
rows, in color order KYKYKYCMCMCM, where K = black, Y = yellow, C = cyan, and M =
magenta. During the printing process, the Printhead would only have to travel approximately 14
pixels horizontally to provide complete coverage. However, the Printhead travels much further,
depending on print resolution, to interlace each jet with the output of neighboring jets.
The jet array is bonded to a cast aluminum ink reservoir. The reservoir supplies the molten ink
to the jet array. Heaters in the reservoir and the jet array maintain the ink at a temperature of
about 140° C for printing.
Theory of Operation
Image Output Terminal
Figure 13 Printhead X-Axis Drive
X-Axis or lateral movement of the Printhead is accomplished using a stepper motor driving a
fine-thread screw system. The Printhead, mounted to the X-Axis shaft, moves laterally across
the surface of the drum.
To find the Printhead home position, the X-Axis system drives the Printhead in an open-loop.
The Printhead is driven against the left frame for a few seconds, and then reversed a set dis-
tance. A tension spring links to the Printhead's left shaft, and provides a preloaded tension so
the Printhead moves smoothly.
Printhead Tilt
The Printhead is able to rotate into four basic positions:
1. Printhead lock / ship position (19.5 degrees): the Printhead restraint pins are resting
against the right and left locks. In this position, the Printhead tilt arm/ follower is free of the
tilt cam, and the head is secured for shipping.
2. Wipe position (12 degrees): the Printhead tilt arm/follower is engaged with the tilt cam,
and the head overload spring contact is engaged with the overload spring-plate to provide
the correct force for the wiper.
3. Standby position (20.9 degrees): allows the wiper to clear the Printhead in order to be in
the start wipe Printhead position, and also allow the Printhead locks to pivot and lock or
unlock the Printhead. In this position, the Printhead tilt arm/ follower is engaged at the
standby position of the tilt cam.
4. Print position (0 degrees): the Printhead is forward and resting against the right and left
head-to-drum buttons. The head-to-drum buttons define the space between the jet stack
and the drum.
10/2006
8-16
Initial Issue
Phaser 8510/8560MFP Multifunction Product