Abstract: A mounting method of an ink container to an ink jet unit mountable to an ink jet recording apparatus, wherein the ink container is mounted while a corner portion of the ink container between a top surface and a rear side is slid in contact with an urging member and while a corner portion of the ink container between a front side and a bottom side is slid toward a front side of the ink jet unit in contact with an inner bottom surface of the ink jet unit.

Abstract: An ink jet unit to which an ink container is detachably mountable, and which is further mountable to an ink jet recording apparatus so as to effect ink jet recording. The ink jet unit includes an ink jet head for ejecting ink for recording, an ink supply tube for receiving ink from the ink container and being provided at a bottom portion of the ink jet unit in fluid communication with the ink jet head, and an opening for permitting mounting of the ink container thereto. The opening is formed continuously, in such sides of the ink jet unit as take top and front positions when the ink jet unit is mounted to the ink jet recording apparatus. A cover is provided, at the top side of the ink jet unit.

Abstract: An ink container cartridge detachably mountable to an ink jet recording head, includes a main body of ink container cartridge; an ink retaining member, in the main body, for retaining the ink; wherein the ink retaining member is contained in the ink container cartridge so that a compression ratio A of the ink retaining member by a side having an ink supply opening of the ink container cartridge and a side opposite therefrom, and a compression ratio B by other two opposite sides thereof, satisfy A>B, and 1.1.ltoreq.A.ltoreq.1.6.