Patent ID: 7686421

Claim:
A method of manufacturing a liquid jet head including a passage-forming substrate in which pressure generating chambers communicating with nozzle orifices for jetting liquid are formed; piezoelectric elements which are provided on one side of the passage-forming substrate with a vibration plate interposed therebetween and cause pressure changes in the pressure generating chambers; and a sealing plate which is made of a single crystal silicon substrate and has a piezoelectric element holding portion for sealing a space sufficient enough so as not to inhibit movement of the piezoelectric elements in a state where the space is ensured, the sealing plate further having a reservoir portion constituting at least part of a reservoir communicating with the pressure generating chambers, the method comprising the steps of: forming a mask pattern on a surface of a sealing plate forming material, which becomes the sealing plate; forming the reservoir portion and the piezoelectric element holding portion by etching the sealing plate forming material except a region where the mask pattern has been formed; removing the mask pattern to form the sealing plate; forming a protective film having resistance to liquid at least on an inner wall surface of the reservoir portion in the sealing plate; and joining the passage-forming substrate, in which the piezoelectric elements have been formed, and the sealing plate.