Patent ID: 8807722

Claim:
An ink cartridge comprising: an ink bag which is formed in a bag shape and which includes two layers of flexible sheets that are disposed to face each other, and which stores ink inside; a plug which is provided on the ink bag and which includes a hollow portion that leads from a first opening that is communicatively connected with the ink bag to a second opening that opens to the outside; a case that is substantially box-shaped, and that includes a first wall portion and a second wall portion, which are a pair of wall portions whose longitudinal direction is an axial line of the plug and which are arranged substantially in parallel with the axial line, a third wall portion that is a wall portion arranged substantially perpendicularly with respect to an extending planar direction of the pair of wall portions and diagonally with respect to the axial line, and a penetration portion that is provided in the third wall portion such that the penetration portion faces the second opening of the plug, the case housing the ink bag such that sheet surfaces of the two layers of sheets respectively face the first wall portion and the second wall portion; and a pressing member that includes a curved portion, which is a surface portion formed by curving, toward an outer side, a sheet having lower flexibility than that of the two layers of sheets such that a one surface of the sheet is on an inner side, such that at least one end portion of the sheet faces the one surface, and such that an empty space is created on the inner side, wherein inside the case; between the ink bag and the first wall portion, the pressing member is elastically deformed and a restoring force occurs in directions in which one section and another section are separated from each other by the one section of the curved portion being in contact with the first wall portion and the other section other than the one section of the curved portion being in contact with a first layer portion that is one of the two layers of sheets, and the empty space is positioned between the one section and the other section.