Xerox Phaser 8860, Руководство по обслуживанию

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09/2007
8-16 Phaser 8860/8860MFP Service Manual
Image Output Terminal
Initial Issue Theory of Operation
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.
The head tilt cam tilts the head into the basic four positions listed above. The cam has five spe-
cial features and associated functions:
1. The cam is combined with a missing tooth gear (Head Tilt Gear) that allows the cam to be
inactive in the print position. This frees the Process Drive to perform other system opera-
tions.
2. The cam has a latching feature to unlatch and latch the missing tooth gear to engage the
Printhead tilt drive train.
3. The cam profile has a standby dwell (the portion of the cam that has a constant radius).
This holds the Printhead back in the standby position
4. The cam profile has a wipe dwell that holds the Printhead back in the wipe position.
5. The cam profile increases the power consumption at a specific phase of rotation. This
allows the software to identify a power consumption footprint to alert the system when the
head is locked in error.
The Printhead is tilted away from the drum and locked for shipping. When the Printhead is
locked in the shipping position there are three key restraining elements:
1. The Printhead is restrained from rotating from the shipping position by pins extending
from both ends of the Printhead into a pocket. These pockets are defined by dampening
pads that limit motion to the back and polycarbonate locks that pivot into the lock position
and limit forward motion toward the drum. The locks are held in the lock position by the
wiper carriage, and are spring-loaded to normally be unlocked.
2. The Printhead is restrained at the X-Axis shafts by the right and left Printhead Restraints
that limit motion at both ends of the Printhead.
3. The Printhead is limited to the nominal motion of 1.7 mm in the X-Axis (left / right side
motion when the Printhead is back and locked) by the right lock and the left home stop on
the left side frame.