Patent ID: 7575306

Claim:
A discharge apparatus, comprising: a liquid chamber which accommodates a liquid to be discharged from a discharge hole onto a discharge receiving medium; an actuator formed on the liquid chamber comprising a piezoelectric body, a thin film member, and a second electrode; the piezoelectric body acts in a d 31 mode which applies a discharge pressure to the liquid inside the liquid chamber; the thin film member which includes a first electrode provided at least on a surface of the piezoelectric body on a side facing the liquid chamber; the second electrode which is provided on a surface of the piezoelectric body on a side opposite to the liquid chamber; a holding plate which is bonded to a surface of the second electrode on a side opposite to the piezoelectric body, wherein a thickness of the thin film member is less than a sum of a thickness of the second electrode and a thickness of the holding plate; and a drive unit applying a discharge voltage to the actuator having an absolute value of the discharge voltage applied between the first electrode and the second electrode of the actuator during the liquid discharge operation, the change in the actuator caused by change in the discharge voltage coincides with the direction which returns the actuator to its initial state when the liquid accommodated in the liquid chamber is discharged by driving the piezoelectric body that is less than the drive unit applying a securing voltage to the actuator having an absolute value of the securing voltage applied between the first electrode and the second electrode of the actuator when the holding plate is secured in position during non-discharge of the liquid accommodated in the liquid chamber and the liquid is discharged by the drive unit applying a pull-in voltage between the first electrode and the second electrode of the actuator to expand the liquid chamber from a state in which the securing voltage is applied between the first electrode and the second electrode of the actuator by the drive unit and then the drive unit applying the discharge voltage between the first electrode and the second electrode of the actuator to reduce the liquid chamber.