Patent ID: 7073894

Claim:
An ink jet printer head, comprising: a cavity unit having a plurality of nozzles arranged in a reference direction, a plurality of pressure chambers which communicate with the nozzles, respectively, and a plurality of partition walls which separate the pressure chambers from each other; a piezoelectric actuator having a plurality of active portions each of which is driven to change a pressure of an ink accommodated in a corresponding one of the pressure chambers, and thereby eject, from a corresponding one of the nozzles, a droplet of the ink, the cavity unit and the piezoelectric actuator being fixed to each other; the piezoelectric actuator comprising a plurality of sheet members which are stacked on each other and include at least one piezoelectric sheet; at least one common electrode; and at least one individual-electrode layer including a plurality of individual electrodes which are aligned with the pressure chambers, respectively, and each of which cooperates with a corresponding one of a plurality of portions of said at least one common electrode to sandwich a corresponding one of a plurality of portions of said at least one piezoelectric sheet, in a direction of stacking of the sheet members, and thereby provide a corresponding one of the active portions of the piezoelectric actuator; the piezoelectric actuator further comprising a plurality of external pads which are provided on an outer surface of an outermost sheet member of the sheet members and are electrically connected to a cable member through which drive signals for said active portions are transmitted; and a plurality of internal leads which electrically connect between the individual electrodes and the external pads, respectively; and the external pads being located, on the outer surface of the outermost sheet member of the piezoelectric actuator, at respective positions that are at least partially aligned with the partition walls each of which is located between corresponding two pressure chambers of the plurality of pressure chambers in said reference direction.