Patent ID: 6948804

Claim:
An ink cartridge comprising: an ink chamber; a valve chamber having a wall, the wall having a protruding portion having a tip and a fixing portion, the tip of the protruding portion being offset from the fixing portion; an ink supply port; a membrane valve seat disposed in the valve chamber to divide the valve chamber into a first compartment and a second compartment, wherein a periphery of the membrane valve seat is fixed to the fixing portion of the wall of the valve chamber, a central portion of the membrane valve seat is displaceable to contact with and separate from the protruding portion of the wall of the valve chamber, the membrane valve seat has a first surface facing the first compartment and receiving a pressure in the ink chamber via the first compartment and a second surface facing the second compartment and receiving a pressure in the ink supply port via the second compartment; and an ink flow passage selectively opened and closed by the displacement of the membrane valve seat central portion caused due to a pressure difference between the first and second compartments, to thereby selectively establish and interrupt fluidic communication between the ink chamber and the ink supply port, wherein the protruding portion of the valve chamber wall is selectively contacted with and separated from the membrane valve seat central portion by the displacement of the membrane valve seat central portion, and contact between the protruding portion of the valve chamber wall and the membrane valve seat closes an opening of the ink flow passage.