Patent ID: 6923528

Claim:
A liquid-jet head comprising: a passage-forming substrate having a plurality of pressure generation chambers communicating with corresponding nozzle orifices; and a plurality of piezoelectric elements provided on one side of said passage-forming substrate via a vibration plate, each of said piezoelectric elements comprising a lower electrode, a piezoelectric layer, and an upper electrode, said passage-forming substrate having a plurality of liquid supply paths that are equal in depth with said pressure generation chambers and communicate with corresponding longitudinal ends of said pressure generation chambers for supplying liquid to said pressure generation chambers, an active piezoelectric section, which substantially serves as a drive section of each of said piezoelectric elements, provided in a region facing a corresponding one of said pressure generation chambers, such that an end of said active piezoelectric section, on a side toward said liquid supply paths, is within said region facing the corresponding one of said pressure generation chambers, a reinforcement film being provided on said vibration plate in regions that face said liquid supply paths, said reinforcement film comprising a nonactive piezoelectric section of each of said piezoelectric elements in regions that face said liquid supply paths, the nonactive piezoelectric section including said piezoelectric layer which extends from said active piezoelectric section but remaining substantially undriven, and an overall internal stress of said reinforcement film and said vibration plate being tensile.