Patent ID: 7018023

Claim:
A liquid-jet head including a passage-forming substrate on which pressure generating chambers communicating with nozzle orifices ejecting liquid are formed; and piezoelectric elements which are provided on one side of the passage-forming substrate through a vibration plate and cause pressure changes in the pressure generating chambers, wherein a covering plate having a piezoelectric element holding portion which covers the piezoelectric elements is joined with a surface of the passage-forming substrate where the piezoelectric elements are provided, and a nozzle plate provided with the nozzle orifices is joined with a surface of the passage-forming substrate opposite to the surface where the covering plate is joined, and a region of the passage-forming substrate facing the piezoelectric element holding portion is thicker than an outside region of the passage-forming substrate facing the piezoelectric element holding portion, when said piezoelectric elements are in a non-activated state.