Patent ID: 8038265

Claim:
A liquid-droplet jetting apparatus which jets droplets of a liquid to an object, the apparatus comprising: a channel unit which includes a plurality of nozzles and a plurality of pressure chambers communicating with the nozzles respectively; a piezoelectric actuator arranged on a surface of the channel unit and including: a vibration plate which covers the pressure chambers; a piezoelectric layer which is arranged on the vibration plate on a side opposite to the pressure chambers; a plurality of first electrodes which are arranged on a surface of the piezoelectric layer at positions facing the pressure chambers respectively and which apply a first electric potential for providing a jetting-pressure to the liquid in the pressure chambers so as to jet the liquid from the nozzles; a plurality of second electrodes which are mutually conducted and arranged on the surface of the piezoelectric layer at positions facing the pressure chambers respectively such that one second electrode which faces one of the pressure chambers is electrically conducted with another second electrode which faces another of the pressure chambers, and which apply a second electric potential for providing a vibrating-pressure to the liquid in the pressure chambers so as to vibrate the liquid without jetting the liquid; and a third electrode which is arranged on the other surface of the piezoelectric layer and which faces the first electrodes and the second electrodes across the piezoelectric layer; and an electric potential-changing mechanism which changes an electric potential of the first electrodes to the first electric potential to apply the jetting-pressure to the liquid in the pressure chambers so as to jet the liquid from the nozzles, and which changes an electric potential of the second electrodes to the second electric potential to apply the vibrating-pressure to the liquid in the pressure chambers.