Patent ID: 7611229

Claim:
An inkjet head comprising: a passage unit comprising a common ink chamber and an individual ink passage leading from an outlet of the common ink chamber through a pressure chamber to an ejection port; and an actuator that can selectively take a first state in which the volume of the pressure chamber is V 1 and a second state in which the volume of the pressure chamber is V 2 larger than V 1 , the actuator changing from the first state into the second state and then returning to the first state to eject ink from the ejection port, the individual ink passage being formed such that the volume Vd of a partial passage in the individual ink passage corresponding to a region from an outlet of the pressure chamber to the ejection port, and the volume Vc of the individual ink passage, satisfy a condition that Vd/Vc is not less than 0.12 and not more than 0.40.