Xerox PHASER 8560MFP, Service Documentation

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10/2006
8-14 Phaser 8510/8560MFP Multifunction Product
Image Output Terminal
Initial Issue Theory of Operation
The Print Process
Once an image has been processed and a printing bitmap created, the print cycle begins. The
Printhead and drum are brought up to their operating temperatures and the ink levels in the ink
reservoirs are checked. Ink is added from the ink loader, if necessary.
In the ready state, the print process consists of the following steps, which are described in this
section:
• Drum Preparation
• Printing
– Ink Loader
– Printhead
– Drum Assembly
– Transfix System
• Purge System
• Transfix and Exiting
WARNING
Keep your fingers away from the Y-Axis drum rotation drive system; it uses a closed-
loop servo drive system and is inherently dangerous; the motor speeds up if it senses
the drive system slowing down, and fingers caught in the belts and gears can be
severely injured.
Drum Preparation
To prepare the Drum, a thin coating of silicone oil is applied to the surface of the Drum. First the
Drum is rotated. Next, the oil roller and blade of the Drum Maintenance Kit are raised into con-
tact with the Drum. To accomplish this, the Process Drive rotates the drum maintenance cam-
shaft lifting the oil and wiper blade to the Drum. The cams on the ends of the camshaft push
against followers on each side of the Drum Maintenance Kit, forcing the oil roller and blade
against the Drum. The Drum is rotated against the oil saturated roller.
Figure 9 Drum Oiling
Printing
To print, the Drum starts rotating at a speed dependent upon print resolution. As the Drum
reaches the correct speed, the jets begin to fire to deposit the image on the oiled portion of the
Drum. As the jets fire, the Printhead moves from right to left to complete the image on the
Drum.
When printing, the system performs a “six-jet interlace,” in which each jet lays down a particular
number of pixel columns, depending on the print resolution. Each jet lays down one pixel col-
umn for each Drum rotation, which varies from eight to 16 rotations, depending on the print res-
olution. Interlacing “averages out” the variability between jets by interlacing each jet with other
jets. In some test prints, the Printhead moves to the right and lays down 309 parallel bands of
ink. Each band is composed of 15 pixel columns of dots from an individual jet.
Jet substitution allows a better performing jet to be used in place of a missing or poorly per-
forming neighboring jet. When jet substitution is used, the Printhead makes a second right-to-
left movement to deposit the pixel columns of the substituted jets. See Jet Substitution Mode.
Ink Loader
The Ink Loader consists of four parallel channels with an ink melting element at the end of each
channel. Ink sticks, one color loaded in each channel, are pressed by coil spring pressure into
the melting elements. As ink is required by the Printhead, the appropriate color’s melting ele-
ment is activated and the end of the ink stick is melted. The melted ink drips into the ink reser-
voirs of the Printhead underneath. Sensors in the Ink Loader alert the customer to install more
ink sticks before the current sticks are completely consumed.