Seiko Epson Corporation

Junhua Chang

Toshihisa Saruta

Takahiro Katakura

Shuji Yonekubo

Tomohiro Sayama

Keiji Matsumoto

Haruo Nakamura

Kenichi Kanbayashi

Hiroe Niimura

Keisuke Nishida

In order to provide a liquid ejection head which enables ejection of a droplet at a higher frequency, according to the invention, a piezoelectric vibrator has a multilayer structure. In the multilayer structure, an upper piezoelectric layer and a lower piezoelectric layer are laminated one on another. A drive electrode is formed at a boundary between the upper piezoelectric layer and the lower piezoelectric layer and is electrically connected to a source for supplying a drive signal. An upper common electrode is formed on the surface of the upper piezoelectric layer. A lower common electrode is formed on the surface of the lower piezoelectric layer. An inertance of a nozzle orifice and an inertance of an ink supply port are set so as to become greater than an inertance of a pressure generating portion.

Liquid ejection head

In order to provide a liquid ejection head which enables ejection of a droplet at a higher frequency, according to the invention, a piezoelectric vibratorhas a multilayer structure. In the multilayer structure, an upper piezoelectric layerand a lower piezoelectric layerare laminated one on another. A drive electrodeis formed at a boundary between the upper piezoelectric layerand the lower piezoelectric layerand is electrically connected to a source for supplying a drive signal. An upper common electrodeis formed on the surface of the upper piezoelectric layer. A lower common electrodeis formed on the surface of the lower piezoelectric layer. An inertance of a nozzle orificeand an inertance of an ink supply portare set so as to become greater than an inertance of a pressure generating portion

A first common electrode is formed on a vibration plate and to be fixed at a predetermined potential. A first piezoelectric layer is laminated on the first common electrode and having a first thickness. A drive electrode is laminated on the first piezoelectric layer, to which a drive signal is supplied externally. A second piezoelectric layer is laminated on the drive electrode and having a second thickness thicker than the first thickness. A second common electrode is laminated on the second piezoelectric layer and to be fixed at the predetermined potential.

Piezoelectric actuator and fluid ejection head having the same

A liquid ejecting apparatus of the invention includes: a pressure-generating chamber having an inside space whose volume is changeable, into which a liquid is supplied and which is communicated with a nozzle, a resonance frequency of said pressure-generating chamber having a period of Tc; a signal-generating unit that generates a driving signal having: a first signal-element for causing the pressure-generating chamber to expand, a second signal-element for causing the pressure-generating chamber to contract from an expanding state thereof in order to eject a drop of the liquid through the nozzle, and a third signal-element for causing the pressure-generating chamber to expand to an original state before outputting the first signal-element after the drop of the liquid is ejected; and a pressure-generating unit that causes the pressure-generating chamber to expand and contract, based on the driving signal. The third signal-element has: a first-step element for causing the pressure-generating chamber to expand to an intermediate contracting state, which is smaller than the original state before outputting the first signal-element; and a second-step element for causing the pressure-generating chamber of the intermediate contracting state to the original state before outputting the first signal-element. The first-step element and the second-step element are substantially discontinuous in at least one of applying time or inclination.

Liquid ejecting apparatus and controlling unit of liquid ejecting apparatus

A drive signal generator generates a drive signal including a drive pulse supplied to a pressure generating element. The drive pulse including a first expanding element, which drives the pressure generating element so as to expand a pressure chamber, so that a meniscus of liquid in a nozzle orifice is pulled toward the pressure chamber, a first contracting element, which drives the pressure generating element so as to contract the pressure chamber expanded by the first expanding element, so that a center portion of the meniscus is swelled in an ejecting direction of a liquid drop, and a second expanding element, which drives the pressure generating element so as to expand the pressure chamber contracted by the first contracting element, so that a marginal portion of the swelled center portion of the meniscus is pulled toward the pressure chamber. The first expanding element is supplied for a time period which is not greater than a half a natural vibration period of the pressure chamber. A potential difference of the first contracting element being not greater than 60% of a potential difference between a minimum potential and a maximum potential of the drive signal.

Liquid jetting apparatus and method of driving the same

The liquid-jetting apparatus has a liquid-jetting head with nozzle openings through which liquid particles are jetted. The liquid-jetting head performs a flushing operation to remove the thickened liquid from the nozzle openings to recover its normal liquid-jetting ability. The flushing operation jets liquid particles having a weight of 10 ng or below successively through the nozzle openings at a jetting speed of 8 m/s or above. The liquid-jetting apparatus is capable of achieving a satisfactory flushing operation to ensure a satisfactory liquid-jetting characteristic by recovering from a thickened state in a liquid in the nozzle openings even if the liquid is un-uniformly thickened in the nozzle openings.

Liquid-jetting apparatus and method of driving the same

A driving signal generation unit generates a plurality of kinds of driving pulses and a minute vibration pulse to be applied to a pressure generation element so as to finely vibrate a meniscus of liquid. A pulse generation unit generates the minute vibration pulse and the driving pulses by selecting a part of the driving signal. The driving signal includes a plurality of waveform elements used to generate the driving pulses and a connection element used to connect the waveform elements between different voltage levels and not used to generate the driving pulses. The pulse generation unit generates the minute vibration pulse by a combination of at least a part of the waveform elements and at least a part of the connection element. A plurality of driving pulses for ejecting a plurality of kinds of ink drops and a minute vibration pulse for causing minute vibrations to a meniscus of liquid can be efficiently put in a driving signal of one driving period.

Liquid jet apparatus and method for driving the same

A drive signal generating unit generates a drive signal sequence COM containing a first pulse, a fourth pulse, and a seventh pulse as a plurality of ejection pulse signals, a second pulse as a fine expansion waveform, and a sixth pulse as a fine contraction waveform. In the drive signal COM, the fourth pulse is placed between the second pulse and the sixth pulse. To finely vibrate a meniscus, the second pulse and the sixth pulse are selectively applied to a piezoelectric vibrator.

Liquid jetting apparatus, method of driving the same, and computer-readable record medium storing the method

A head member includes a plurality of first nozzles forming a first nozzle row, a plurality of second nozzles forming a second nozzle row that is paired with the first nozzle row, and an ink supplying unit that supplies a same kind of liquid to each of the nozzles. There is a slight gap between a moving track of a first nozzle by a main scanning unit and a moving track of a second nozzle paired with the first nozzle by the main scanning unit. A controlling unit is adapted to control an ink jetting unit and the main scanning unit in such a manner that an ink jetting from the first nozzle and an ink jetting from the second nozzle paired with the first nozzle are carried out in a same main scan, based on jetting data for a same jetting unit area. According to the invention, even if main scans are not repeated, liquid jetting for the same jetting unit area can be carried out from the two nozzles.

Liquid jetting apparatus

An ink jet recording apparatus comprises a recording head including a pressure generating element provided in association with a pressure generating chamber communicating with a nozzle orifice, an ink drop is jetted from the nozzle orifice by applying a drive pulse to the pressure generating element, drive signal generating means for generating a drive signal, and drive pulse generating means for generating a drive pulse from the drive signal. The drive signal generated by the drive signal generating means contains wave elements capable of activating the pressure generating element and a connection element incapable of activating the pressure generating chamber and for connecting connection ends of the wave elements having different voltage levels. The drive pulse generating means appropriately selects the wave elements in the drive signal and composes them into the drive pulse.

Driver for ink jet recording head

Disclosed is a method of driving an ink jet printhead having flexural or longitudinal vibration mode piezoelectric elements. The method includes a contracting step for expanding the pressure generating chamber until a velocity of the trailing edge of the ejected ink drop is substantially zero at a position near the nozzle orifice. The printhead ejects an ink drop having small volume without a reduction in ink drop velocity.

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Nagano, Japan

Junhua Chang