US Patent 7585061 Ejection head and image forming apparatus

The ejection head includes 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, wherein the bonding member comprises a low-rigidity member; and the piezoelectric element has a greater length than an internal effective length of the pressure chamber.