Patent ID: 7533972

Claim:
An inkjet head, comprising: a plurality of ink discharge nozzles which are arranged two-dimensionally; a plurality of pressure chambers which are in communication with the ink discharge nozzles so as to store ink, the pressure chambers being two-dimensionally arranged in correspondence with the ink discharge nozzles; a plurality of piezoelectric elements; a common electrode which is disposed on pressure chamber sides of the piezoelectric elements; a plurality of discrete electrodes which are disposed on sides of the piezoelectric elements opposite to the common electrode; and a plurality of discrete lead electrodes which feed electricity to the discrete electrodes, wherein: each of the piezoelectric elements is deformed by applying voltage to the common electrode and the discrete electrode so that a volume of the pressure chamber is varied to discharge a droplet of the ink from the ink discharge nozzle; where thickness is defined as the shortest straight-line distance between any point on one surface and an opposite surface, with respect to each pair of the discrete electrode and discrete lead electrode corresponding to each of the pressure chambers, when T 1 is a thickness of the discrete electrode and T 2 is a thickness of the discrete lead electrode which feed electricity to the discrete electrode, the discrete electrode and the discrete lead electrode are configured so that T 1 and T 2 satisfy the following formula: T1<T2; and further, wherein: when D is a width of the discrete electrode in the same direction as a width of the discrete lead electrode, d is the width of the discrete lead electrode, and N is a number of rows in the breadthways direction of the two-dimensionally arranged pressure chambers, the discrete electrode, the discrete lead electrode, and the pressure chambers are configured so that the D, the d, and the N satisfy the following formula: D ( N 2 ) > d ⁢ ⁢ where ⁢ ⁢ N > 2.