Patent ID: 8342661

Claim:
An inkjet printing apparatus including a printing head having an ejection portion configured to eject ink and an ink supplying apparatus configured to supply the ink to the printing head, the ink supplying apparatus comprising: a liquid chamber which reserves ink supplied to the ejection portion; an air releasing portion which releases air in a space provided at an upper side of the liquid chamber to an outside; an air introducing portion which introduces air of the outside into the space; and a control portion which controls a negative pressure in the space by adjusting an air releasing amount from the air releasing portion, wherein the air releasing portion releases air in the space and air from the air introducing portion via an air passage to the outside by a fan, and wherein the air passage includes a portion having a first passage which communicates with the space, a second passage which communicates with the air releasing portion, and a third passage which communicates with the air introducing portion, and wherein in the portion all of the first, second and third passages are connected, wherein the supplying apparatus further comprises: a pressure detecting sensor provided in the first passage; and a valve provided between the space and the first passage, the valve being operable to block and release the first passage from the space, wherein before ejection of ink from the ejection portion, and in a state where the valve blocks the first passage, the control portion drives the fan and thereafter releases the first passage by the valve, responsive to a detection by the pressure detecting sensor of a predetermined pressure in the first passage.