US 2007/0176978 A1Published application

Liquid-droplet jetting apparatus and liquid-droplet jetting method

AssigneeBrother Kogyo Kabushiki Kaisha

InventorHiroto Sugahara

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Abstract

An ink-jet head includes a piezoelectric layer, pressure chambers, nozzles, first electrodes, and second electrodes. When electric potentials of the first and second electrodes respectively are changed at the same timing such that increase and decrease in the electric potentials are opposite between the first and second electrodes, volume of the pressure chamber is changed to apply jetting-pressure to ink in the pressure chamber, thereby jetting an ink droplet from the nozzle. When only the electric potential of the second electrode is changed, the volume of the pressure chamber is changed to apply a vibrating-pressure lower than the jetting-pressure to the ink in the pressure chamber, thereby vibrating meniscus of the ink, agitating the ink in the nozzle. This makes it possible to suppress increase in viscosity of the ink in the nozzle.

Claims20

Dependent claims

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, 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.

6 more elements

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;
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;
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
a controller which controls electric potentials of the first electrodes and second electrodes to supply to the first electrodes a first electric potential for jetting the liquid from the nozzles, and to supply to the second electrodes a second electric potential for vibrating the liquid in the nozzles without jetting the liquid.

6 more elements

Dependencies are inferred from the claim text.