Patent ID: 7748835

Claim:
An ink cartridge, adapted to be mounted on an ink jet recording apparatus, comprising: a container body, including a wall having a first face; an ink chamber, containing ink therein; a differential pressure valve; a valve chamber, accommodating the differential pressure valve therein and including an opening opened at the first face of the wall; a groove, formed on the first face of the wall; and a first film, covering the opening and the groove; and a second film, wherein: the first face of the wall includes a first part defining an edge of the opening, a second part formed with the groove, and a third part which is other than the first part and the second part; a passage communicating the ink chamber with atmosphere is defined at least in part, by the first film and the groove; and the ink chamber is defined by the second film and a second face of the wall which is an opposite side face of at least the third part of the first face of the wall.