Purge Unit Structure - Canon BJC-2000 Service Manual

Part 4: Technical Reference

3.3.2 Purge unit structure

1) Purge drive gear
Through a transmission gear, the purge drive gear is driven by the feed roller which
is driven by the paper feed motor. The purge drive gear in turn drives the cam which
controls the pump's operation.
The cam's position is detected by the home position sensor via the sensor arm.
2) Wiper unit
When the carriage moves from left to right, the wiper retracts so that it does not
touch the head. However, when the carriage moves from right to left, the wiper wipes
ink from the BJ cartridge's face plate at the following times:
Once every 60 seconds (or when the specified dot count is reached) during printing,
when the paper pick-up operation ends, when the recovery operation ends, and
when the cap is opened or closed.
3) Capping unit
The capping unit has a rubber cap. When the carriage moves to the home position,
the cap is pressed against the print head's face plate.
Also, since the cap is connected to a pump, the cap sucks ink from the BJ cartridge
during the cleaning operation. The ink which has been sucked out is sent to the
base cover unit's waste ink absorber.
4) Maintenance jet receiving section
The maintenance jet receiving section takes in ink (for test ejection to maintain the
nozzles' working condition) ejected from the BJ cartridge. The ink is received, and
when a gear is rotated, the ink is sent to the waste ink absorber below.
5) Slide lock pin
The slide lock pin moves the cap when the carriage moves from left to right and reaches
the capping position after moving from left to right. Capping is executed while the slide
arm is unlocked.
When the slide arm is unlocked, the rotation of the feed roller is transmitted to the
purge drive gear and sheet feeder.
6) Ink shield
The ink shield stops ink splattering when the wiper unit wipes off ink.
Purge Unit Drive Gear
Maintenance Jet Receiving Section
Slide Lock Pin
Wiper Unit
Figure 4-14 Purge Unit
4-18
BJC-2000
Capping Unit
Ink Shield