Patent ID: 6174051
Filing Date: 2001-01-16
Classification: B41J

Abstract:
An ink jet head including ink pressure chambers formed in a cavity plate, each ink pressure chamber being open in one plane thereof;at least two or more piezoelectric layers fixed on the cavity plate so as to cover the open plane of the ink pressure chamber, each of the at least two or more piezoelectric layers including first inner electrodes each disposed at a position corresponding to each said ink pressure chamber and second inner electrodes each disposed in a periphery of the ink pressure chamber;a power source having a first terminal to which the first inner electrodes are connected and a second terminal to which the second inner electrodes are connected and has a polarity different from the first terminal;said first and second inner electrodes produce electric deformation of a part of the piezoelectric layer upon application of an actuating voltage between the first and second inner electrodes from the power source, to jet ink from the ink pressure chamber via an ink jetting orifice, said ink jet head comprising:a laminated piezoelectric element formed of said at least two or more piezoelectric layers so that said first and second inner electrodes are individually stacked up, the laminated piezoelectric element being polarized in a direction of lamination;an outer piezoelectric layer stacked on a surface of the laminated piezoelectric element, the surface being positioned at an opposite side to the ink pressure chambers and the outer piezoelectric layer being polarized in a direction of thickness; andan outer electrode formed on one side of the outer piezoelectric layer, connected to said second terminal of the power source;wherein, upon application of the actuating voltage from the power source, an electric field in a direction perpendicular to the polarization direction of the laminated piezoelectric element is generated in the laminated piezoelectric element to deform the same in a shear mode, and an electric field in a direction parallel to the polarization direction of the outer piezoelectric layer is generated in the outer piezoelectric layer to deform the same in an expansion mode.