Patent ID: 7178909

Claim:
An ink cartridge, comprising: a cartridge case having a first side wall, a second side wall opposite from the first side wall, a front wall and a back wall opposite from the front wall; a bottom plate attached to a first end of the cartridge case; and a cover attached to a second end of the cartridge case; wherein: the bottom plate includes an ink port through which ink is transmitted to an exterior of the cartridge during operation, the ink port being positioned closer to the first side wall than to the second side wall; the bottom plate includes a recessed portion, the recessed portion being recessed with respect to an adjacent unrecessed area of the bottom plate and being positioned closer to the second side wall than to the first side wall; the recessed portion is formed in a shape capable of accommodating an engagement protrusion of an image forming apparatus; the recessed portion includes a particular portion that is not open to the exterior of the ink cartridge on a front-wall side and on a back-wall side, the particular portion of the recessed portion being capable of accommodating the engagement protrusion of an image forming apparatus; the ink port is situated between the first side wall and the recessed portion; and a diameter of the ink port is smaller than a width of the recessed portion.