Service Manual 2-21Purge SystemProper 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 airbubbles that may be obstructing the printhead nozzles. The waste ink that is expelledduring the purge is funneled into the waste tray. Following the purge, a wipe operationis performed on the faceplate using the wiper blade. After the wipe, a cleaning page isprinted.To perform a printhead maintenance cycle, the printhead is first tilted away from thedrum, to allow the wiper assembly to pass by. The wiper blade is then raised in frontof the printhead. Wiper movement is governed by the media path drive, by engaging aclutch on the exit shaft of the printer. The purge pump applies pressure to the inkreservoir for approximately 2.5 seconds. Valves in the reservoir seal when pressure isapplied. The pressurization ejects a small amount of ink from the jets. Following thepressure purge, the printhead is tilted into the wiper assembly and the wipe cyclebegins. The pump runs again with the solenoid for approximately 30 seconds,creating a neutral balance between pressure and ink. The wiper blade lowers andwipes excess ink from the jets into the ink waste tray. A proper purge will layer thelength of the waste tray with a single layer of ink about 20 mm wide.s8400-147Wiper bladePrintheadPurge pumpPurge tube2.5 sec
