Patent ID: 7055922

Claim:
An ink jet head, comprising: a head assembly provided with a plurality of nozzles and a plurality of pressure chambers storing ink therein and communicated respectively to the nozzles; actuators each associated with one of the pressure chambers and each including a piezoelectric element, a scanning electrode provided on one side of the piezoelectric element, and a recording electrode provided on the other side of the piezoelectric element, wherein the actuators are arranged in a matrix pattern of n rows by m columns (where n and m are natural numbers equal to or greater than two) in terms of electrical circuit, with recording electrodes of each row being electrically connected to one another, and scanning electrodes of each column being electrically connected to one another; and a driving circuit for supplying a scanning signal to the scanning electrodes for each column, while supplying a recording signal to each row of the recording electrodes in synchronization with the scanning signal, wherein a voltage of a driving signal obtained by combining the scanning signal with the recording signal varies among at least two or more actuator columns, wherein when ink is to be discharged, the driving signal includes an ink discharging pulse signal for driving an actuator so as to discharge ink and an auxiliary pulse signal for driving an actuator to such a degree that ink is not discharged, and when ink is not to be discharged, the driving signal includes the auxiliary pulse signal for driving an actuator to such a degree that ink is not discharged; and a voltage of the ink discharging pulse signal varies among at least two or more actuator columns.