Patent ID: 9227420
Filing Date: 2016-01-05
CPC Classification: B41J

Claim Text:
1. An inkjet printing apparatus comprising: a printing unit having: a pressurizing-side atmospheric air opening valve for switching the pressurizing tank between a sealed state and an atmospheric air open state; a negative-pressure side atmospheric air opening valve for switching the negative-pressure tank between a sealed state and an atmospheric air open state; an air pump for feeding air from the negative-pressure tank to the pressurizing tank; and a control unit configured to bring the pressurizing tank and the negative-pressure tank into the sealed state, respectively, by the pressurizing-side atmospheric air opening valve and the negative-pressure side atmospheric air opening valve, to feed ink from the pressurizing tank toward the inkjet head by bringing about a state in which a positive pressure is applied to the pressurizing tank and a negative pressure is applied to the negative-pressure tank by the air pump, and to circulate ink along the circulation path by controlling driving of the ink pump in accordance with liquid level heights of the pressurizing tank and the negative-pressure tank, wherein the control unit, when starting ink circulation, executes preparatory processing of