Purge System - Xerox Phaser 8400 Service Manual

Purge System

Proper printhead operation is dependant on the correct operation of the Purge System.
The purge system uses air pressure and a wiper blade to purge any debris or air
bubbles that may be obstructing the printhead nozzles. The waste ink that is expelled
during the purge is funneled into the waste tray. Following the purge, a wipe operation
is performed on the faceplate using the wiper blade. After the wipe, a cleaning page is
printed.
Wiper blade
2.5 sec
Purge tube
Printhead
Purge pump
s8400-147
To perform a printhead maintenance cycle, the printhead is first tilted away from the
drum, to allow the wiper assembly to pass by. The wiper blade is then raised in front
of the printhead. Wiper movement is governed by the media path drive, by engaging a
clutch on the exit shaft of the printer. The purge pump applies pressure to the ink
reservoir for approximately 2.5 seconds. Valves in the reservoir seal when pressure is
applied. The pressurization ejects a small amount of ink from the jets. Following the
pressure purge, the printhead is tilted into the wiper assembly and the wipe cycle
begins. The pump runs again with the solenoid for approximately 30 seconds,
creating a neutral balance between pressure and ink. The wiper blade lowers and
wipes excess ink from the jets into the ink waste tray. A proper purge will layer the
length of the waste tray with a single layer of ink about 20 mm wide.
Service Manual 2-21