Image Number 7 for United States Patent #7413292.
The present invention is directed to a method for driving a piezoelectric ink jet head comprising a piezoelectric actuator AC that includes two piezoelectric ceramic layers 7a, 7b having such a size that covers the plurality of pressure chambers 2, wherein an electric field of opposite sense to the polarizing direction is applied to the second piezoelectric ceramic layer 7b by using the common electrodes 8a, 8b and, (1) for the pressure chambers 2 from which the ink is discharged, an electric field of the same sense as the polarizing direction of the layer is applied to the first piezoelectric ceramic layer 7a by using the individual electrode 10 and the first common electrode 8a, thereby causing the region of the piezoelectric actuator AC to deflect toward the pressure chamber 2, while (2) for the pressure chambers 2 from which the ink should not be discharged, an electric field of the opposite sense to the polarizing direction is applied to the first piezoelectric ceramic layer 7a by using the electrodes 10, 8a, thereby to maintain the region of the piezoelectric actuator AC in the initial state, so as to discharge an ink droplet selectively through the nozzle 3 that communicates with the pressure chamber 2 described in (1) and form a dot.
|
