Patent ID: 7926925

Claim:
An ink pack, comprising: a film bag that has a sealed chamber therein and is formed of a flexible film member having a form of a bag; a tap that has an ink flow channel therein and is welded to one edge of the flexible film member; a film welding part, in which opposed inner surfaces of the flexible film member are welded to each other, formed at least along the one edge of the flexible film member; and a tap welding part, in which a side of the tap is welded to opposed inner surfaces of the flexible film member, formed in the one edge of the flexible film member, wherein a welding width, in a direction in which ink flows through the ink flow channel, of a side of the film welding part neighboring the tap welding part is larger than a welding width, in the direction in which the ink flows through the ink flow channel, of a side of the tap welding part neighboring the film welding part, and a difference between the welding width of the film welding part and the welding width of the tap welding part forms a cylindrical recessed portion extending in a direction parallel to the direction in which ink flows through the ink flow channel, the cylindrical recessed portion being between the sealed chamber and the tap welding part.