Patent ID: 7654650

Claim:
An ink-jet head including: a passage unit in which formed are a common ink chamber and a plurality of individual ink passages, each individual ink passage extending from an outlet of the common ink chamber through at least one of a plurality of pressure chambers to one of a plurality of ink ejection ports; and an actuator unit that is fixed to a plane defined by a surface of the passage unit and gives ejection energy to ink in at least one pressure chamber of the plurality of pressure chambers, wherein: a plurality of closed passages, each having a shape of the individual ink passage being partially closed are formed in the passage unit; wherein the plurality of ink ejection ports corresponding to the plurality of the pressure chambers are aligned such that when each of the plurality of ink ejection ports is projected in a particular direction onto an imaginary line that is parallel to the plane defined by the surface of the passage unit, the projected points of each of the plurality of ink ejection ports onto the imaginary line align at regular intervals, wherein the particular direction is perpendicular to the imaginary line; and wherein the plurality of closed passages are formed in a region that is enclosed by a contour of the actuator unit when viewed in a plan view, and a length of the actuator unit intersected by an imaginary plane formed perpendicular to the imaginary line varies as the imaginary plane is displaced along the imaginary line.