Patent ID: 6991313

Claim:
An ink jet printer, comprising: a print head having a plurality of ink jet nozzles arranged in plural columns; an ink cartridge including an ink accommodation chamber having a deformable wall and an air chamber for exerting via the wall air pressure on ink accommodated in the ink accommodation chamber; an ink supply tube connecting the ink cartridge to the print head; an air pump for producing pressurized air for changing a state of ink that is located at a tip portion of each of the ink jet nozzles; an air supply tube for guiding the pressurized air to the air chamber of the ink cartridge; and a maintenance unit including a cap member for covering the print head, wherein the maintenance unit opens the cap member while the air pump supplies the pressurized air to the air chamber of the ink cartridge such that the pressurized air projects the ink in a convex shape from a tip portion of each of the ink jet nozzles.