Patent ID: 8047628

Claim:
A printing apparatus to form an image on a recording medium according to print data representing the image, comprising: a recording head, which ejects ink onto the recording medium; an ink cartridge, which contains the ink therein; an ink cartridge storage to store the ink cartridge; an ink conveyer tube, which connects the recording head and the ink cartridge to convey the ink; a maintenance system having an aspirator to aspirate the ink to be drawn in the recording head and the ink conveyer tube and a cap to cover a nozzle surface of the recording head when the ink in the recording head and the ink conveyer tube is aspirated; and a releasing system, which is arranged in the ink conveyer tube to switch an open state in which air flow in the ink conveyer tube is released and a closed state in which the air flow in the ink conveyer tube is shut down, the releasing system being arranged in a position higher than a position of the ink cartridge so that the releasing system and the ink cartridge have a predetermined water head difference therebetween, wherein: the releasing system includes: an electrically-operable valve to be switched between an open position and a closed position, and a valve controller to control switching motions of the electrically-operable valve, the valve controller controlling the electrically-operable valve to be in the open position to release the air flow in the ink conveyer tube so that the ink in the recording head and the ink conveyer tube is withdrawn into the ink cartridge, the valve controller controlling the electrically-operable valve to be in the closed position after the ink in the recording head and the ink conveyer tube is withdrawn in the ink cartridge; and the maintenance system includes a maintenance controller, which controls the cap to cover the nozzle surface of the recording head and the ink in the recording head and the ink conveyer tube to be aspirated when the valve controller switches the electrically-operable valve to be in the closed position so that the air flow in the ink conveyer tube is shut down, and controls the cap to cover the nozzle surface of the recording head and the ink in the recording head and the ink conveyer tube to be aspirated so that the ink once withdrawn in the ink cartridges is drawn again in the recording head and the ink conveyer tube to be used.