Patent ID: 8740358

Claim:
A liquid ejection head, comprising: a pressure generating portion, provided in an ink channel communicating a common ink chamber and a nozzle orifice; a vibration plate, which defines a part of the pressure generating portion, so that liquid in the pressure generating portion is ejected from the nozzle orifice as a liquid droplet by deforming the vibration plate; a piezoelectric vibrator, provided on a surface of the vibration plate which is opposite to a surface facing the pressure generating portion; and a liquid supply port, arranged between the common ink chamber and the pressure generating portion to serve as an orifice, wherein the piezoelectric vibrator has a multilayer structure which comprises: an upper piezoelectric layer and a lower piezoelectric layer, laminated one on another; a drive electrode, formed at a boundary between the upper piezoelectric layer and the lower piezoelectric layer, and electrically connected to a supply source of a drive signal; an upper common electrode, formed on a surface of the upper piezoelectric layer; and a lower common electrode, formed on a surface of the lower piezoelectric layer; and wherein an inertance of the nozzle orifice and an inertance of the liquid supply port are greater than an inertance of the pressure generating portion, a length of the piezoelectric vibrator is longer than a length of the pressure generating portion in a longitudinal direction of the pressure generating portion.