Xerox Phaser 8400 Service Manual page 204

If the printer was not shutdown by the power switch the last time it
was turned off or it was shutdown with ink on the drum:
1.
As soon as the printer has warmed up, the media path motor moves the wiper to
the bottom of its travel and the process motor moves the printhead to the print
position a chase page is sent through the paper path to clean ink from the drum.
If printhead, ink reservoirs, or jetstack temperature are below purge
threshold, the printer performs a head clean cycle.
1.
The printer waits for the printhead to reach its purge temperature.
2. The printer moves the wiper to the bottom of its travel and tilts the printhead
forward to its print position to check the ink levels. If the ink level is low, ink is
melted into the appropriated reservoirs.
3. The printhead tilts to the standby position and moves the wiper assembly to the
purge position in front of the printhead faceplate.
4.
The purge pump begins the pressure purge after about 2 seconds the purge pump
solenoid opens.
5.
The printhead tilts forward against the wiper assembly (wipe position) and the
purge and wipe cycle begins.
6. The Control Panel indicates the printer is performing the cleaning process.
7. The printhead is moved left to the tilt zone, where the printhead can tilt back
without interference, and the media path motor moves the wiper to the bottom of
its travel to engage the printhead tilt cam. The process motor rotates the printhead
tilt gears, which tilt in order to move the printhead to the forward print position.
8.
After the print engine is in a known, valid state the Control Panel display shows
the warm-up progress (the Ready LED flashes). When warm-up completes, the
Ready LED displays solid.
9. The temperature of the printhead, drum and paper preheater are allowed to
stabilize at their operating temperatures and ink is melted if needed.
10.
The printhead is homed to the print position for printing.
11.
A cleaning page is printed at this time, if a purge was performed.
12.
A start page is printed (if enabled).
13. The Control Panel displays a message that the printer is initializing and then
ready.
14.
The print engine is initialized and is ready to print.
4-64 Phaser 8400/8500/8550 Color Printer