Ink-jet head, ink jet printer, and its driving method
AssigneeSeiko Epson Corporation
InventorsMasahiro Fujii, Hiroyuki Ishikawa, Yasushi Matsuno
Life of this patent
Estimating the term…
Abstract
An ink-jet head ejects an ink droplet from an ink nozzle by the charging and discharging between a counter electrode and vibrating plates. The counter electrode comprises a main electrode and an auxiliary electrode, which is provided on the ink-nozzle's side in common with the vibrating plates. Auxiliary charging between the auxiliary electrode and the vibrating plates is effected to vibrate a meniscus in the ink nozzle without ejecting a useless droplet. Consequently, the ink is prevented from forming a film on the meniscus, and an increase of the viscosity of the ink due to evaporation of the ink solvent is prevented by diffusing the ink in the ink passage.
Claims19
An ink jet head, comprising:
- a plurality of ink nozzles for ejecting ink;
- a plurality of ink chambers, each communicating with a respective one of the plurality of ink nozzles;
- a plurality of ink supply channels, each for supplying ink to a respective one of the plurality of ink chambers;
- a plurality of elastically displaceable diaphragms, each formed in a circumferential wall of a respective one of the plurality of ink chambers;
- and
- a plurality of groups of electrodes, each group positioned so as to oppose a respective one of the plurality of diaphragms with intervention of a gap;
- wherein each group of electrodes is charged and discharged relative to the respective diaphragm to eject ink droplets from the respective ink nozzle;
- wherein, for each group of electrodes, each electrode in that group is electrically independent of the other electrodes in that group;
- and
- wherein at least one electrode in one group of electrodes opposing one of the diaphragms is electrically connected to at least one electrode in another group of electrodes opposing another of the diaphragms.
An ink jet printer, comprising:
- an ink jet head including:
- a plurality of ink nozzles for ejecting ink;
- a plurality of ink chambers, each communicating with a respective one of the plurality of ink nozzles;
- a plurality of ink supply channels, each for supplying ink to a respective one of the plurality of ink chambers;
- a plurality of elastically displaceable diaphragms, each formed in a circumferential wall of a respective one of the plurality of ink chambers;
- and
- a plurality of groups of electrodes, each group positioned so as to oppose a respective one of the plurality of diaphragms with intervention of a gap;
- wherein each group of electrodes is charged and discharged relative to the respective diaphragm to eject ink droplets from the respective ink nozzle;
- wherein, for each group of electrodes, each electrode in that group is electrically independent of the other electrodes in that group;
- and
- wherein at least one electrode in one group of electrodes opposing one of the diaphragms is electrically connected to at least one electrode in another group of electrodes opposing another of the diaphragms.
A method for driving an ink jet head which includes a plurality of ink nozzles for ejecting ink;
- a plurality of ink chambers, each communicating with a respective one of the plurality of ink nozzles;
- a plurality of ink supply channels, each for supplying ink to a respective one of the plurality of ink chambers;
- a plurality of elastically displaceable diaphragms, each formed in a circumferential wall of a respective one of the plurality of ink chambers;
- and a plurality of groups of electrodes, each group positioned so as to oppose a respective one of the plurality of diaphragms with intervention of a gap;
- wherein, for each group of electrodes, each electrode in that group is electrically independent of the other electrodes in that group;
- wherein at least one electrode in one group of electrodes opposing one of the diaphragms is electrically connected to at least one electrode in another group of electrodes opposing another of the diaphragms;
- and wherein the method comprises the step of:
- electrically charging and discharging the groups of electrodes relative to the respective diaphragms in accordance with a predetermined pattern so as to eject ink droplets from the ink nozzles.
Dependencies are inferred from the claim text.