Hitachi Koki Co., Ltd.

Hitachi Printing Solutions, Ltd.

Nobuhiro Noto

Yoshitaka Akiyama

Takuji Torii

Kenichi Kugai

Kenji Yamada

Shigenori Suematsu

Hiroshi Takahagi

Nobuhiro Kurosawa

Yasuo Takano

Kazuaki Akimoto

Yutaka Shoji

Kazuo Shimizu

Osamu Machida

Takahiro Yamada

Hitoshi Kida

Satoru Tobita

Takashi Sato

Mamoru Okano

Toshitaka Ogawa

Makoto Kurosawa

Stuart D Howkins

Katsunori Kawasumi

Yoshinari Suzuki

Hiroomi Kozawa

Tadahiro Kaneko

Yo Kawakami

Hiroyasu Ishikawa

Charles A Willus

Satsuo Sato

Norimasa Kondo

Osamu Kawanobe

Masatoshi Sakata

Takao Matsuoka

Kazunobu Hayashi

Takeshi Toyoshima

Takao Abe

Akira Kashimura

Ryoji Yabuki

Juurou Kobayahsi

Takayoshi Kaneta

Keiji Watanabe

Takuji Toru

An inkjet head includes a pair of support plates A, B and a diaphragm plate interposed between the support plates A, B. In this configuration, even when adhesion between the diaphragm plate and the support plate B is insecure, and when a piezoelectric element deforms a diaphragm toward a pressure chamber , that is, in a direction away from the support plate B, the support plate A prevents the diaphragm plate from peeling off the support plate B. Accordingly, the dimension and thus a deforming amount of the diaphragm is maintained uniform, whereby a uniform ink ejection performance is maintained.

Configuration of inkjet head realizing uniform ink ejection performance

An ink jet print head includes pressure chambers, nozzles, and ink channels in a one-to-one correspondence. A diaphragm forms a side of each pressure chamber. The ink channels are formed in a restrictor plate. Piezoelectric elements are attached to the diaphragm and to a piezoelectric element fixing plate, which supports the piezoelectric elements. A housing of the head is formed with a common ink channel for supplying ink to the ink channels and an internal space into which the piezoelectric elements and the piezoelectric element fixing plate are at least partially inserted. A cover is provided for covering the piezoelectric element fixing plate. The cover is connected to the housing and is provided with an internal space large enough to maintain a gap between the cover and the piezoelectric element fixing plate.

Ink jet print head and method of production thereof

An ink jet print head includes pressure chambers, a diaphragm forming a side of the pressure chambers, stacked piezoelectric elements, a piezoelectric element fixing plate, and a housing. The stacked piezoelectric elements are attached to the diaphragm in a one-to-one correspondence with pressure chambers. The piezoelectric element fixing plate is fixedly attached to and supports the stacked piezoelectric elements. The housing includes a common ink channel portion that supplies ink to the pressure chambers. The piezoelectric element fixing plate and the stacked piezoelectric elements are disposed at least partially in the space defined by the diaphragm and internal side walls of the ink channel portion with a gap existing between the piezoelectric element fixing plate and the internal side walls.

An appropriate pulse width of a driving pulse for driving a piezoelectric element of ink jet head is determined by using the head difference. That is, the pulse width with which the least change in the ink speed occurs can be used as the pulse width of the driving signal for the piezoelectric actuator. As a result, a reliable ink jet printer head capable of stably ejecting ink droplets over a long period of time and having excellent frequency characteristics can be provided.

Drive method for ink jet head

During a method for manufacturing an ink-jet print head, piezoelectric element bars are fixed to a base plate. Then, two corners of the piezoelectric element bars are cut. The bare are then diced to be separated into individual piezoelectric elements.

Method of manufacturing ink jet print head

An ink jet printhead composed of: a reservoir storing a quantity of printing ink, an ink manifold defining an ink supply volume in communication with the reservoir for holding a supply of ink received from the reservoir and a plurality of individually controlled ink jet delivery channels, each of the channels having an ink drop ejection transducer and an orifice to eject successive ink drops on demand in response to pressure pulses produced by the transducer, and each of the channels being in communication with the ink supply volume for receiving ink from the ink supply volume. The manifold is constructed to give the ink supply volume a large acoustic compliance to minimize propagation of pressure disturbances in the ink supply volume and acoustic signal crosstalk between the channels.

Ink jet printhead with reduced crosstalk

To increase the size of dot printed on a print medium with an on-demand multi-nozzle ink jet head, at least two unit pulses are applied in succession to a piezoelectric element which varies the volume of an ink chamber. The unit pulse has a pulse width substantially equal to a period of Helmholtz natural oscillation determined based on dimensions, materials, and physical properties of an ink channel and the piezoelectric element and other components relating to oscillation. An off duration between adjacent unit pulses applied in succession to the piezoelectric element is preferably set one fifth to one fourth of the unit pulse width.

Drive method for an on-demand multi-nozzle ink jet head

To eliminate influence of cross-talk in an on-demand multi-nozzle ink jet head, drive pulses to be applied to piezoelectric elements for driving nozzles aligned in a row are individually adjusted so that the nozzles eject ink droplets at the same speed when the nozzles are driven simultaneously. To the piezoelectric elements which are deactuated during printing, a dummy drive pulse having a voltage level in a range from 50 to 75% of a minimum voltage for ejecting an ink droplet is applied, whereby the ejection speed achieved when individual nozzles are driven approaches the ejection speed achieved when all nozzles are driven simultaneously. As such, the print quality is improved.

Drive voltage adjusting method for an on-demand multi-nozzle ink jet head

A print head for ink jet printer having a reduced length in a main scanning direction and an elongated length in an auxiliary scanning direction perpendicular to the main scanning direction. A plurality of linear print head modules are arrayed in the auxiliary scanning direction, and each linear print head module extends in a slanting direction with respect to the main scanning direction by a predetermined angle. Further, each linear print head module has a width in a direction perpendicular to its extending direction. The slanting angle and the width determine scanning pitch extending in the auxiliary scanning direction and can reduces the length of the print head in the main scanning direction.

Print head having array of printing elements for printer

An on-demand ink jet head includes a plurality of piezoelectric elements in alignment with one another with one end of each facing in the same direction. The end of each piezoelectric element is bonded by an adhesive material to a diaphragm which, together with a nozzle plate, forms a pressurizing chamber. To confine the fluid state adhesive material expelled out of the endmost piezoelectric elements, a dummy piezoelectric element is disposed outside each endmost piezoelectric element. The adhesive material, when dried, serves as a damper of the piezoelectric element for damping unwanted vibrations of the piezoelectric elements. By the provision of the dummy piezoelectric elements, the distribution of the adhesive material becomes substantially even between the piezoelectric elements, resulting in uniform operations of the piezoelectric elements.

Multi-nozzle ink jet head with dummy piezoelectric elements at both ends of a piezoelectric element array for controlling the flow of adhesive about the piezoelectric element array

A piezoelectric element is driven by a predetermined pulse width in the range of 60 to 100% of the Helmholtz resonance vibration period of an ink vibration system comprising an orifice, a pressurizing chamber, a restrictor, the piezoelectric element, and an elastic material.

Method of minimizing ink drop velocity variations in an on-demand

An on-demand multi-nozzle ink jet head includes a diaphragm and a plurality of piezoelectric stacks. The diaphragm forms at least one wall of a pressurizing chamber used to increase the pressure of the ink. When print signals are applied to the piezoelectric stacks. The stacks generate pressure fluctuations in the walls of the pressurizing chamber. An elastic material with adhesive properties is used to bond the diaphragm to the piezoelectric stacks, which elastic material has a Shore hardness of less than 80 on the A scale and less than 30 on the D scale.

On-demand multi-nozzle ink jet head

A grinder has a grinding member. The grinder includes a rotatable spindle having an engagement portion. A first flange engages the engagement portion of the spindle. The first flange and the engagement portion of the spindle define a given play therebetween in a direction of rotation. The grinding member is held between the first flange and a second flange. A lubricant solid material is provided between the first flange and the engagement portion of the spindle.

Portable grinder

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Hitachinaka, Japan

Nobuhiro Noto