Epson Scan 2500 service manual Cap Mechanism

EPSON Stylus Scan 2500 Revision A

2.2.7 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.

Position A	Positions B and C
	Carriage flag

Ink Eject Valve

Negative Pressure

Valve

Closed-	Open-valve
	state
valve state

Frame

flag

Figure 2-17. Cap mechanism and valve operation

Operating Principles Printer Mechanism Operation 49