Patent ID: 7891785

Claim:
A liquid jet head comprising: a flow passage forming substrate in which a pressure generating chamber communicating with a nozzle for ejecting liquid droplets; a piezoelectric element which is formed above one surface of the flow passage forming substrate and each includes a lower electrode, a piezoelectric layer, and an upper electrode; and a joining substrate which is adhered onto the one surface of the flow passage forming substrate by an adhesive and includes a piezoelectric element preserver which is a space ensuring that drive of the piezoelectric element is not interrupted, wherein each of the lower electrodes is independently provided in correspondence to the pressure generating chamber to serve as an individual electrode of the piezoelectric element, wherein the upper electrode is continuously formed in an arrangement direction of the pressure generating chambers to serve as a common electrode piezoelectric elements, wherein the lower electrode in the area opposed to the pressure generating chamber is formed so as to have a width narrower than a width of the pressure generating chamber, and an upper surface and an end surface of the lower electrode in an area corresponding to the pressure generating chamber are covered with the piezoelectric layer, wherein an upper surface of the piezoelectric layer in the area opposed to the pressure generating chamber and a side surface of the piezoelectric layer in an arrangement direction of the piezoelectric elements are covered with the upper electrode, and wherein on one end in a longitudinal direction of the piezoelectric element, the piezoelectric layer extends up to an adhesive area of the flow passage forming substrate to which a circumferential portion of the piezoelectric element preserver of the joining substrate is adhered, and the lower electrode extends up to the outside of an end portion of the piezoelectric layer to form a terminal section in an end portion of the lower electrode.