JPH01235649A - Ink jet head - Google Patents

Ink jet head

Info

Publication number
JPH01235649A
JPH01235649A JP6245788A JP6245788A JPH01235649A JP H01235649 A JPH01235649 A JP H01235649A JP 6245788 A JP6245788 A JP 6245788A JP 6245788 A JP6245788 A JP 6245788A JP H01235649 A JPH01235649 A JP H01235649A
Authority
JP
Japan
Prior art keywords
ink
nozzle
outlet orifice
ink outlet
area
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP6245788A
Other languages
Japanese (ja)
Inventor
Koichi Higashimura
東村　公一
Masanao Matsuzawa
松澤　正尚
Hisashi Miyazawa
久 宮澤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seiko Epson Corp
Original Assignee
Seiko Epson Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Seiko Epson Corp filed Critical Seiko Epson Corp
Priority to JP6245788A priority Critical patent/JPH01235649A/en
Publication of JPH01235649A publication Critical patent/JPH01235649A/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2/14201—Structure of print heads with piezoelectric elements
    • B41J2/14282—Structure of print heads with piezoelectric elements of cantilever type

Abstract

PURPOSE:To allow improvement of characteristics such as ink droplet discharge speed, discharge amount, discharge stability and response to be achieved simultaneously by increasing the area of an ink inlet orifice in a nozzle beyond the size of the area of an ink outlet orifice, and providing a straight cylindrical side on the ink outlet orifice as a nozzle side. CONSTITUTION:A nozzle-equipped substrate 11 is provided with a plurality of nozzles 15 whose area ratio of an ink inlet orifice 12 to an ink outlet orifice 13 is more than 1 and whose nozzle side of the ink outlet orifice 13 is straight- cylindrical. The pressure of ink existing in the gap between a pressure- generating member 18 and the nozzle 15 increases and ink droplets are discharged from the nozzle. As the area of the ink inlet orifice of the nozzle is broader than that of the ink outlet orifice 13, a sufficient quantity of ink penetrates through the ink inlet orifice 12, proceeding to the ink outlet orifice 13 by increasing of the speed due to a reduction of nozzle cross section. However, the increased speed of ink is stopped and the flow is uniformized in the straight cylindrical nozzle side of the ink outlet orifice 13. Consequently, the ink is discharged in the form of stable ink droplets.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、インクの中に浸されて（＼る圧力発生部材に
電圧を印加して圧力発生部材を変位させ、ノズルとの間
隙に存在するインクの圧力を高めてノズルからインク滴
を吐出させる機構のインクジェットヘッドに関する。Detailed Description of the Invention [Field of Industrial Application] The present invention applies a voltage to a pressure generating member that is immersed in ink to displace the pressure generating member and displace the pressure generating member that exists in the gap between the nozzle and the The present invention relates to an inkjet head with a mechanism that increases the pressure of ink to eject ink droplets from a nozzle.

〔従来の技術〕[Conventional technology]

複数のノズルをイイするノズル形成基板と、ノズルの各
々と対向配置し、インクの中に浸されている圧力発生部
材とを備え、電圧印加により圧力発生部材を変位させ、
ノズルとの間隙に存在するインクの圧力を高めてノズル
からインク滴を吐出させるオンデマンド型インクジェッ
トヘッドは＄１１えば特開昭５７−１７８７６８等に提
案されており、このインクジェットａ構は、インク滴の
吐出安定性に優れ、インク中に気泡・ゴミ等が混入した
場合でもその影響を受けず：こ正常なインク滴の吐出が
可能であるという特徴を有している。A nozzle forming substrate for forming a plurality of nozzles, a pressure generating member disposed opposite each of the nozzles and immersed in ink, and displacing the pressure generating member by applying a voltage,
An on-demand inkjet head that ejects ink droplets from the nozzle by increasing the pressure of the ink existing in the gap between the nozzle and the nozzle has been proposed in Japanese Patent Application Laid-open No. 57-178768. It has excellent ejection stability, and is characterized by being able to eject normal ink droplets without being affected by air bubbles, dirt, etc. mixed into the ink.

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

このタイプのインクジェットヘッドにおいては、ノズル
側面形状がインクジェット特性に大きな影響を与える事
が判明しているものの、満足のいく特性を獲得する事は
非常に難しく、各特性間のトレードオフによってノズル
側面形状が選ばれ採用されていた。即ち、ノズル側面形
状を、ノズルのインク入口開口部の面積がインク出口開
口部の面積よりも広い所謂ホーン形状に設計する事は、
インク滴の吐出スピード並びに吐出量のアップに貢献す
る半面、インク滴を吐出した後にノズル内へ引き込まれ
るインクメニスカスの曲率半径が大きくなるため毛細管
力が小さくなってインクメニスカスの戻り時間が長くか
かる様になり応答性の低下を招いていた。また、ノズル
内でのインクの流れが不均一になりやすく、インク滴の
吐出が不安定になって劣悪な記録品質となりがちであっ
た。In this type of inkjet head, it is known that the shape of the nozzle side surface has a large effect on the inkjet characteristics, but it is extremely difficult to obtain satisfactory characteristics, and the nozzle side shape was selected and adopted. In other words, designing the side surface of the nozzle into a so-called horn shape in which the area of the ink inlet opening of the nozzle is wider than the area of the ink outlet opening is as follows:
While this contributes to increasing the ejection speed and amount of ink droplets, it also increases the radius of curvature of the ink meniscus that is drawn into the nozzle after ejecting the ink droplets, which reduces the capillary force and makes it take longer for the ink meniscus to return. This resulted in a decrease in responsiveness. Furthermore, the flow of ink within the nozzle tends to become non-uniform, and the ejection of ink droplets tends to become unstable, resulting in poor recording quality.

更に、ノズル側面形状を、ノズルのインク入口開口部の
面積とインク出口開口部の面積とが等しい所謂直筒側面
形状に設計すると、ノズル内でのインクの流れが均一と
なるためインク滴の安定な吐出が達成出来る半面、イン
ク滴の必要吐出スピードと必要吐出量の確保が困難とな
った。Furthermore, if the nozzle side shape is designed to be a so-called straight cylindrical side shape in which the area of the ink inlet opening and the area of the ink outlet opening of the nozzle are equal, the flow of ink within the nozzle becomes uniform, resulting in stable ink droplets. Although ejection could be achieved, it became difficult to secure the necessary ejection speed and amount of ink droplets.

本発明の目的は、これらの技術課題を解決して、インク
滴の吐出スピード・吐出量・吐出安定性・応答性といっ
た緒特性の向上を同時に達成し、性能の優れたインクジ
ェットヘッドを提供する事にある。The purpose of the present invention is to provide an inkjet head with excellent performance by solving these technical problems and simultaneously achieving improvements in the performance characteristics such as ink droplet ejection speed, ejection amount, ejection stability, and response. It is in.

〔課題を解決するための手段〕[Means to solve the problem]

本発明におけるインクジェットヘッドは、複数のノズル
を有するノズル形成基板と、ノズルの各々と対向配置し
、インクの中に浸されている圧力発生部材とを備え、電
圧印加により圧力発生部材を変位させ、ノズルとの間隙
に存在するインクの圧力を高めてノズルからインク滴を
吐出させるインクジェットヘッドであって、ノズルのイ
ンク入口開口部とインク出口開口部の面積比が１以上で
あり、かつインク出口開口部のノズル側面が直筒側面形
状である事を特徴とする。An inkjet head according to the present invention includes a nozzle forming substrate having a plurality of nozzles, a pressure generating member disposed facing each of the nozzles and immersed in ink, and displacing the pressure generating member by applying a voltage. An inkjet head that ejects ink droplets from the nozzle by increasing the pressure of ink existing in a gap between the nozzle and the nozzle, wherein the area ratio of the ink inlet opening to the ink outlet opening of the nozzle is 1 or more, and the ink outlet opening The nozzle side surface of the section is characterized by a straight cylinder side surface shape.

〔作用〕[Effect]

本発明の上記の構成によれば、ノズルのインク入口開口
部の面積がインク出口開口部の面積よりも広いためにイ
ンク滴の吐出スピード並びに吐出量のアップが実現出来
ると同時に、インク出口開口部のノズル側面が直筒側面
形状であるためにノズル出口付近でのインクの流れが均
一となってインク滴の安定な吐出が確保出来る。According to the above configuration of the present invention, since the area of the ink inlet opening of the nozzle is wider than the area of the ink outlet opening, it is possible to increase the ejection speed and amount of ink droplets, and at the same time, the ink outlet opening can increase the ejection speed and amount of ink droplets. Since the side surface of the nozzle is shaped like a straight cylindrical side surface, the flow of ink near the nozzle outlet becomes uniform, and stable ejection of ink droplets can be ensured.

〔実施例〕〔Example〕

本発明における実施例を、図面に基づき説明する。 Embodiments of the present invention will be described based on the drawings.

第１図は、本発明におけるインクジェットヘッドを搭載
した記録装置の一実施例を説明するための斜視図である
。記録媒体１は、送りローラー２・３の押圧によりプラ
テン４に捲き回され、記録の進行に従い矢印５の方向に
搬送される。ガイド軸６・７に案内されプラテン４の軸
と平行な方向に移動可能なキャリッジ８上には、複数の
ノズルを有するインクジェットヘッド９が搭載されてお
り、矢印ＩＯの方向に移動しつつ各々のノズルからイン
ク滴を吐出して記録媒体上にインク像を形成する。FIG. 1 is a perspective view for explaining an embodiment of a recording apparatus equipped with an inkjet head according to the present invention. The recording medium 1 is wound around the platen 4 by the pressure of the feed rollers 2 and 3, and is conveyed in the direction of the arrow 5 as recording progresses. An inkjet head 9 having a plurality of nozzles is mounted on a carriage 8 that is guided by guide shafts 6 and 7 and movable in a direction parallel to the axis of the platen 4, and each inkjet head 9 is moved in the direction of an arrow IO. An ink image is formed on a recording medium by ejecting ink droplets from a nozzle.

第２図は、本発明におけるインクジェットヘッド９の構
造並びにインク滴の吐出原理を説明するためのヘッド断
面図である。ノズル形成基板１１には、インク入口開口
部１２とインク出口開口部１３０面積比が１以上であり
、かつインク出口開口部１３のノズル側面が直筒側面形
状１４である、複数のノズル１５が設けられ、各々のノ
ズル１５には圧電素子１６と金属板１７の積層材から成
る圧力発生部材１８が対向配置され、インク１９中に浸
された構造となっている。圧電素子１６に電圧２０を印
加すると、圧電素子１６が収縮し金属板１７とで形成す
るバイメタル効果によって圧力発生部材１８がノズルの
方向へ変形し、この変形によって圧力発生部材１８とノ
ズル１５との間隙に存在するインクの圧力が高まり、ノ
ズルからインク滴が吐出する。この時、ノズルのインク
入ロ開ロ部１２０面積がインク出口開口部１３の面積よ
りも広いため、十分な量のインクがインク入口開口部１
２がら侵入、ノズル断面積の減少による速度増幅を受け
ながらインク出口開口部１３へ向かうが、インク出口開
口部１３のノズル側面の直筒側面形状１４部に於いて、
インクの加速の停止並びに流れの均一化の作用を受け、
安定なインク滴となって吐出される。このインク滴の吐
出安定性に関しては、インク出口開口部１３のノズル側
面の直筒側面形状１４部のインク流路長を１０μｍ以上
に設定した時に効果が現われ始める事が実験により確認
されている。FIG. 2 is a sectional view of the inkjet head 9 for explaining the structure of the inkjet head 9 and the principle of ejecting ink droplets according to the present invention. The nozzle forming substrate 11 is provided with a plurality of nozzles 15 in which the area ratio of the ink inlet opening 12 to the ink outlet opening 130 is 1 or more, and the nozzle side surface of the ink outlet opening 13 has a straight cylinder side surface shape 14. A pressure generating member 18 made of a laminated material of a piezoelectric element 16 and a metal plate 17 is disposed facing each nozzle 15 and is immersed in the ink 19. When a voltage 20 is applied to the piezoelectric element 16, the piezoelectric element 16 contracts and the pressure generating member 18 deforms in the direction of the nozzle due to the bimetallic effect formed with the metal plate 17, and this deformation causes the pressure generating member 18 and the nozzle 15 to The pressure of the ink existing in the gap increases, and ink droplets are ejected from the nozzle. At this time, since the area of the ink inlet opening 120 of the nozzle is wider than the area of the ink outlet opening 13, a sufficient amount of ink flows into the ink inlet opening 1.
2, the ink enters the ink and moves toward the ink outlet opening 13 while undergoing speed amplification due to the reduction in the nozzle cross-sectional area.
Due to the effect of stopping the acceleration of ink and equalizing the flow,
The ink is ejected as stable ink droplets. Regarding the ejection stability of ink droplets, it has been confirmed through experiments that the effect begins to appear when the ink flow path length of the straight cylindrical side surface 14 of the nozzle side of the ink outlet opening 13 is set to 10 μm or more.

第３図は、本発明におけるインクジェットヘッド９に用
いられるノズル側面形状の別の実施例を説明するための
ノズル形成基板１１の断面図である。本実施例における
ノズル側面形状は、インク入口開口部１２とインク出口
開口部１３０面積比が１以上、かつインク出口開口部１
３のノズル側面が底筒側面形状１４であり、さらにイン
ク入口開口部１２の側面がノズル形成基板１１となす角
２１が概ね９０°であって、インク出口開口部１３のノ
ズル側面の立筒側面に滑らかに連結した側面形状となっ
ている。本形状を採用する事により、圧力発生部材の変
位からインク滴の吐出に至るまでのインクの流れが極め
て自然な流れとなるため、さらに効率の良い、安定した
特性を有するインクジェットヘッドが実現出来る。FIG. 3 is a sectional view of the nozzle forming substrate 11 for explaining another embodiment of the nozzle side shape used in the inkjet head 9 of the present invention. The side shape of the nozzle in this embodiment is such that the area ratio of the ink inlet opening 12 and the ink outlet opening 130 is 1 or more, and the ink outlet opening 1
The nozzle side surface of No. 3 has a bottom tube side surface shape 14, and the angle 21 that the side surface of the ink inlet opening 12 makes with the nozzle forming substrate 11 is approximately 90 degrees, and the nozzle side surface of the ink outlet opening 13 has a vertical tube side surface. It has a side shape that smoothly connects to the By adopting this shape, the flow of ink from the displacement of the pressure generating member to the ejection of ink droplets becomes an extremely natural flow, so an inkjet head with even higher efficiency and stable characteristics can be realized.

〔発明の効果〕〔Effect of the invention〕

以上述べたように、本発明によれば、インク入口開口部
とインク出口開口部の面積比が１以上であり、かつイン
ク出口開口部のノズル側面が底筒側面形状であるノズル
を用いるため、インク滴の吐出スピード並びに吐出量の
アップと、インク滴の安定吐出の確保が同時に達成出来
る。さらに、本発明においては、インク滴を吐出した後
にノズル内へ引き込まれるインクメニスカスが、引き込
まれるインクの流れの均一性のために、インク出口開口
部の立筒側面を延長した様な曲率半径か小さい形状とな
るため、強い毛細管力が作用し、インクメニスカスの戻
り時間が速く、高応答性が達成出来る。こうして、イン
ク滴の吐出スピード・吐出量・吐出安定性・応答性とい
った緒特性が同時に向上した、性能の優れたインクジェ
ットヘッドを提供する事が出来、本インクジェッ］・ヘ
ッドを搭載する事により、高性能の記録装置を実現する
事が可能となる。As described above, according to the present invention, a nozzle is used in which the area ratio of the ink inlet opening to the ink outlet opening is 1 or more, and the nozzle side surface of the ink outlet opening has a bottom cylinder side surface shape. It is possible to simultaneously increase the ejection speed and amount of ink droplets and ensure stable ejection of ink droplets. Furthermore, in the present invention, the ink meniscus that is drawn into the nozzle after ejecting ink droplets has a radius of curvature that is like an extension of the vertical cylinder side of the ink outlet opening, in order to ensure uniformity of the flow of the drawn ink. Due to the small size, strong capillary force acts, the return time of the ink meniscus is fast, and high responsiveness can be achieved. In this way, we were able to provide an inkjet head with excellent performance, which simultaneously improved the ejection speed, ejection volume, ejection stability, and responsiveness of ink droplets. It becomes possible to realize a high-performance recording device.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、本発明におけるインクジェットヘッドを搭載
した記録装置の一実施例を説明するための斜視図、第２
図は、本発明におけるインクジェットヘッドの構造並び
にインク滴の吐出原理を説明するためのヘッド断面図、
第３図は、本発明におけるインクジェットヘッドに用い
られるノズル側面形状の別の実施例を説明するためのノ
ズル形成基板の断面図。 １・・・記録媒体 ９・・・インクジェットヘッド １１・・・ノズル形成基板 １２・・・ノズル入口開口部 １３・・・ノズル出口開口部 １４・・・底筒側面形状　　１５・・・ノズル１８・・
・圧力発生部材　　１９・・・インク第１図FIG. 1 is a perspective view for explaining one embodiment of a recording device equipped with an inkjet head according to the present invention, and FIG.
The figure is a cross-sectional view of the inkjet head for explaining the structure of the inkjet head and the principle of ejecting ink droplets in the present invention.
FIG. 3 is a sectional view of a nozzle forming substrate for explaining another embodiment of the nozzle side shape used in the inkjet head of the present invention. 1... Recording medium 9... Inkjet head 11... Nozzle forming substrate 12... Nozzle inlet opening 13... Nozzle outlet opening 14... Bottom tube side shape 15... Nozzle 18...・
・Pressure generating member 19...Ink Figure 1

Claims (1)

【特許請求の範囲】[Claims] 複数のノズルを有するノズル形成基板と、前記ノズルの
各々と対向配置し、インクの中に浸されている圧力発生
部材とを備え、電圧印加により前記圧力発生部材を変位
させ、前記ノズルとの間隙に存在するインクの圧力を高
めて前記ノズルからインク滴を吐出させるインクジェッ
トヘッドにおいて、前記ノズルのインク入口開口部とイ
ンク出口開口部の面積比が１以上であり、かつ前記イン
ク出口開口部のノズル側面が直筒側面形状である事を特
徴とするインクジェットヘッド。A nozzle forming substrate having a plurality of nozzles, and a pressure generating member disposed opposite to each of the nozzles and immersed in ink, and displacing the pressure generating member by applying a voltage to reduce the gap between the nozzles and the nozzles. In an inkjet head that ejects ink droplets from the nozzle by increasing the pressure of ink present in the nozzle, the area ratio of the ink inlet opening and the ink outlet opening of the nozzle is 1 or more, and the nozzle of the ink outlet opening An inkjet head characterized by a side surface shaped like a straight cylinder.
JP6245788A 1988-03-16 1988-03-16 Ink jet head Pending JPH01235649A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6245788A JPH01235649A (en) 1988-03-16 1988-03-16 Ink jet head

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6245788A JPH01235649A (en) 1988-03-16 1988-03-16 Ink jet head

Publications (1)

Publication Number Publication Date
JPH01235649A true JPH01235649A (en) 1989-09-20

Family

ID=13200750

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6245788A Pending JPH01235649A (en) 1988-03-16 1988-03-16 Ink jet head

Country Status (1)

Country Link
JP (1) JPH01235649A (en)

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