Patent ID: 7585061

Claim:
An ejection head, comprising: a wall member which forms a pressure chamber and has an ejection aperture through which droplets of a liquid are ejected onto an ejection receiving medium, the pressure chamber accommodating the liquid to be ejected from the ejection aperture; a diaphragm which causes a volume of the pressure chamber to change by performing bending deformation so as to cause the liquid accommodated in the pressure chamber to be ejected from the ejection aperture, the diaphragm forming one face of the pressure chamber; a piezoelectric element which causes the diaphragm to perform bending deformation in accordance with a drive signal, the piezoelectric element being disposed on the diaphragm; and a bonding member which bonds the diaphragm with the wall member, a diaphragm plate which is divided by a groove structure into a plurality of regions, wherein the diaphragm corresponds to one of the regions and wherein depth of the groove structure determines the position of the groove structure on the diaphragm plate adjacent to the bonding member; wherein the bonding member has a rigidity lower than that of the wall member of the pressure chamber; and the piezoelectric element has a greater length and a width than an internal effective length and an internal effective width of the pressure chamber thereby to suppress reduction in pressure generated by the piezoelectric element.