INK TANK AND INK CARTRIDGE

PROBLEM TO BE SOLVED: To eject ink without hindrance by suppressing ink pressure applied to a sleeve tube. SOLUTION: This ink tank 10 includes an ink storage part 11 formed sealed in flat bag shape with a plastic sheet, and the sleeve tube 20 with one end connected to the inside of the ink storage part 11 and with the other end exposed to the outside while having a through hole inside. The ink storage part 11 includes a weld 15 with front and rear sheets welded in strip shape from a peripheral edge on the side provided with the sleeve tube 20 toward a peripheral edge facing the peripheral edge to open an ink passage 17 between the weld 15 and the facing peripheral edge. The ink storage part 11 further includes a weld 16 from a peripheral edge facing the weld 15 with the sleeve tube 20 in between toward the weld 15 to open an ink passage 18 between the weld 16 and the weld 15, thereby partitioning the inside of the ink storage part 11 into a plurality of regions communicating with each other. COPYRIGHT: (C)2011,JPO&INPIT