Patent ID: 7891781

Claim:
An ink jet head, comprising: a passage unit including a plurality of pressure chambers each communicating with a nozzle for ejecting ink, the plurality of pressure chambers being arranged along a plane to neighbor each other; and an actuator unit fixed to a surface of the passage unit for changing the volume of each of the pressure chambers, the actuator unit being formed to extend along the pressure chambers, the actuator unit including a plurality of pressure generation portions respectively corresponding to the pressure chambers, the actuator unit having a profile with five or more straight portions, each of the straight portions being connected with a neighboring straight portion at one of a right angle or an obtuse angle, such that the actuator unit is resistant to breaking, wherein a plurality of actuator units are arranged along a longitudinal direction of the passage unit, the plurality of actuator units including a first actuator unit and a second actuator unit, the first and second actuator units overlapping each other along a lateral direction of the passage unit, and the pressure chambers are arranged to form pressure chamber lines, each pressure chamber line being oriented along a straight line that extends through an upper acute portion of each pressure chamber of an associated pressure chamber line and crosses a lower oblique side of each pressure chamber in another pressure chamber line neighboring an upper side of the associated pressure chamber line.