Epson Stylus SCAN 2000 Service Manual page 44

EPSON Stylus Scan 2000
2.2.6.1 Cap Mechanism
The cap mechanism prevents ink from thickening and sticking on the head surface
when the printer is not in operation and it also plays a part in cleaning the printhead.
During the power-off sequence, the printhead moves to the right where the head
surface and cap come into contact, and the head surface contacts the rubber frame of
the cap surface until the power is turned back on.
An absorber pad is spread in the cap and can hold a certain amount of ink which is
absorbed from the head without draining it to the waste ink pad. Also, below the
absorber pad, there are two valves that control the adhesion pressure between the head
and cap surface. There is also one exit and tube to drain ink to the waste ink pads.
Position A
When the carriage is out of the HP (for example in the printable area or paper feed
position), the valves on the cap mechanism stay in Position A (closed) as shown to the
right.
Position B
When the carriage returns to the right, it catches the carriage flag on the cap
mechanism. This raises the cap to meet the head surface. This position is used for head
cleaning because the valves are still closed but the rubber around the cap traps air, so
when the pump sucks air away from the cap, a vacuum is created and ink is sucked
away from the head surface. Ink absorption and slight ink absorption are performed in
Position B.
Position C
By moving the carriage a little further to the right, the frame flag on the cap mechanism
contacts the frame and the air valve opens. When the carriage is in this position and the
pump sucks air, no ink is absorbed from the head surface but ink left in the absorber
pad in the cap is drained.
Operating Principles
Position A
Figure 2-17. Cap mechanism and valve operation
Printer Mechanism Operation
Positions B and C
Carriage flag
Ink Eject Valve
Negative Pressure
Valve
Closed-valve
state
Frame flag
Revision A
Open-valve state
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