Operating a piezoelectric actuator membrane of a pressure chamber

摘要

A method of controlling a pressure of a fluid in a pressure chamber, which pressure chamber is delimited by an actuator membrane having a first piezoelectric portion arranged in a central zone of the actuator membrane and at least one second piezoelectric portion arranged in at least one peripheral zone of the actuator membrane; and an ink jet printing device. In a neutral stage, a first flexure state of the actuator membrane is provided by applying first and second voltages to respective piezoelectric portions. In an activation stage, the first and second voltages are temporarily varied, without reversing their polarity, such that a curvature of the central part of the actuator membrane and a curvature of the peripheral part of the actuator membrane are changed in opposite directions, in order to expell a droplet of fluid through a nozzle.

主权项

1. A method of controlling a pressure of a fluid in a pressure chamber, which pressure chamber is delimited by an actuator membrane, wherein the actuator membrane comprises a first piezoelectric part arranged in a central part of the actuator membrane and at least one second piezoelectric part arranged in at least one peripheral part of the actuator membrane, the method comprising:
a neutral stage for providing a first flexure state of the actuator membrane, the neutral stage comprising: applying a first voltage to the first piezoelectric part, thereby generating a first electric field in the first piezoelectric part; and applying a second voltage to the second piezoelectric part, thereby generating a second electric field in the second piezoelectric part; and an activation stage for temporarily providing a second flexure state of the actuator membrane, the activation stage comprising: temporarily varying the first voltage and the second voltage, without reversing a polarity of the first voltage and without reversing a polarity of the second voltage, such that a curvature of the central part of the actuator membrane and a curvature of the at least one peripheral part of the actuator membrane are changed in opposite directions, and a pressure wave is generated in the pressure chamber to expel a droplet of an ink supplied to the pressure chamber, wherein the first piezoelectric part is arranged over the pressure chamber in a central portion of the pressure chamber, and the second piezoelectric part is at least partially arranged over the pressure chamber, and wherein the curvature of the central part of the actuator membrane and the curvature of the at least one peripheral part of the actuator membrane are caused by the corresponding piezoelectric part extending or contracting in a lateral direction parallel to the actuator membrane.