Patent ID: 7954936

Claim:
An ink cartridge comprising: an ink chamber configured to store ink therein, wherein the ink chamber is defined by at least one wall, and an air layer is formed in the ink chamber between a surface of the ink and at least a portion of the at least one wall; and a pump configured to selectively supply air to the air layer and to draw air from the air layer, the pump comprising: at least one wall which defines an air space therein, and the air space is in fluid communication with the air layer, wherein the pump is configured to change a volume of the air space; a tube, the tube having: an inner space formed therethrough by an inner surface of the tube; a first end; and a second end opposite the first end, wherein the inner space is configured to be in fluid communication with the ink chamber via the first end, and the inner space is configured to be in fluid communication with an atmosphere via the second end; and a movable member positioned in the inner space and configured to selectively move in the inner space in a first direction such that the air space decreases and in a second direction opposite the first direction such that the air space increases, wherein a portion of the movable member contacts the inner surface of the tube, and the movable member prevents fluid communication between the ink chamber and the atmosphere via the movable member regardless of whether the movable member moves in the first direction or the second direction.