Patent ID: 7997670

Claim:
A liquid-ejection apparatus, comprising: a head configured to eject a liquid from a plurality of liquid-ejection openings; a main tank configured to accommodate the liquid supplied to the head; a liquid-supply pump configured to supply the liquid in the main tank to the head; a sub-tank in which are formed (a) a connection opening for connecting the sub-tank to the head and (b) an air-discharge opening for communicating the sub-tank with ambient air; a first channel extending from the liquid-supply pump to the sub-tank via the head and the connection opening; a second channel extending from the sub-tank to the liquid-supply pump; a third channel extending from the air-discharge opening of the sub-tank to the ambient air; an air-discharge valve provided in the third channel so as to be openable and closable; and a controller configured to control operations of the liquid-ejection apparatus, wherein the controller controls the air-discharge valve such that the air-discharge valve is in its opened state in a state in which the liquid-supply pump is not driven in a liquid introducing operation in which the liquid is introduced from the main tank to the liquid-supply pump, wherein the controller controls the air-discharge valve such that the air-discharge valve is opened in an air discharging operation in which air that has been separated from the liquid inside the sub-tank by driving the liquid-supply pump to cause the liquid to be flowed through the first channel, is discharged through the third channel, and wherein the controller controls the air-discharge valve such that the air-discharge valve is closed in times other than the liquid introducing operation and the air discharging operation.