Patent ID: 6840602

Claim:
An inkjet head, comprising: a plurality of pressure chambers, each of which is configured such that an end thereof is connected to a discharging nozzle and the other end is connected to an ink supplier, each of said pressure chamber having a shape defined by a longitudinal length and a width which is not longer than the longitudinal length; and an actuator unit for said plurality of pressure chambers, wherein said actuator unit includes: a plurality of planar piezoelectric layers covering over said plurality of pressure chambers; a planar common electrode provided on one side surface of at least one of said plurality of planar piezoelectric layers; and a plurality of planar driving electrodes provided for said pressure chambers, respectively, said plurality of driving electrodes being formed on the other side of said at least one of said plurality of planar piezoelectric layers, wherein said plurality of planar piezoelectric layers include an active layer sandwiched between said common electrode and said plurality of driving electrodes, and an inactive layer which is not sandwiched by said common electrode and driving electrodes, wherein, when each of said plurality of driving electrodes is set to have a voltage different from the potential of said common electrode, a portion of said active layer corresponding to the driving electrode deforms in accordance with piezoelectric transverse effect, a unimorph effect being generated by the deformation of said active layer in association with the inactive layer to vary a capacity of each pressure chamber, and wherein conditions: 0.1 mm≦L, and 0.29 ≦δ/L≦ 1, are satisfied, wherein L represents the width of a pressure chamber and δ represents a length of a driving electrode extending in parallel with the width L.