JPH0550599A - Liquid drop jet device - Google Patents
Liquid drop jet deviceInfo
- Publication number
- JPH0550599A JPH0550599A JP21546191A JP21546191A JPH0550599A JP H0550599 A JPH0550599 A JP H0550599A JP 21546191 A JP21546191 A JP 21546191A JP 21546191 A JP21546191 A JP 21546191A JP H0550599 A JPH0550599 A JP H0550599A
- Authority
- JP
- Japan
- Prior art keywords
- ink flow
- flow path
- ink
- piezoelectric
- length
- 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.)
- Granted
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
- B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
- B41J2202/01—Embodiments of or processes related to ink-jet heads
- B41J2202/10—Finger type piezoelectric elements
Landscapes
- Particle Formation And Scattering Control In Inkjet Printers (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、液滴噴射装置に係り、
特に圧電トランスデューサとして圧電厚みすべり効果に
より変形する圧電素子を用いたプリンタヘッド（液滴噴
射装置）の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet ejecting device,
In particular, the present invention relates to an improvement of a printer head (droplet ejecting device) using a piezoelectric element that deforms as a piezoelectric transducer due to a piezoelectric thickness sliding effect.
【０００２】[0002]
【従来の技術】近年、プリンタヘッドに圧電式インクジ
ェットを利用したタイプのものが提案されている。この
タイプのプリンタヘッドは、圧電アクチュエータの寸法
変位に基づきインク流路の容積を変化させることによ
り、その容積減少時にインク流路内のインクをオリフィ
スから噴射し、逆に容積増大時に他方の弁からインク流
路内にインクを導入するようにしたものであり、ドロッ
プオンデマンド方式と呼ばれる。かかる噴射装置を多数
互いに近接配置し、所定位置の噴射装置からインクを噴
射させることにより、所望する文字や画像を形成するよ
うにしている。2. Description of the Related Art In recent years, a type of printer head using a piezoelectric ink jet has been proposed. This type of printer head changes the volume of the ink flow path based on the dimensional displacement of the piezoelectric actuator, so that the ink in the ink flow path is ejected from the orifice when the volume decreases, and conversely from the other valve when the volume increases. Ink is introduced into the ink flow path, which is called a drop-on-demand method. A large number of such ejection devices are arranged close to each other, and ink is ejected from the ejection device at a predetermined position to form a desired character or image.
【０００３】この種の液滴噴射装置としては、本出願人
が先に提案した特願平３−５４６６９号がある。この液
滴噴射装置のアレイの例の断面図を図５に示す。図５に
示すように、１個のインク流路４は変形可能な６個の側
壁５に囲まれ、この側壁５はインク流路４方向（図中紙
面に垂直方向）に分極され、かつ、厚み方向に電極６を
介して駆動電界が印加される。分極方向と駆動電界方向
とが直交しているので、前記６個の側壁５は圧電厚みす
べりモードの変形により前記インク流路４内側に変形
し、インク流路４内のインク圧を増加させてオリフィス
（図示せず）から液滴を噴射する。この液滴噴射装置
は、前述の如く圧電素子に複数の貫通孔を設け貫通方向
に分極し、その貫通孔表面に駆動用電極を設けることに
より、ヘッドのマルチ化、高解像度化、小形化、単純構
造化を図り、製造コストの低減を実現している。An example of this type of droplet ejecting apparatus is Japanese Patent Application No. 3-54669 previously proposed by the present applicant. A cross-sectional view of an example of the array of this droplet ejection device is shown in FIG. As shown in FIG. 5, one ink flow path 4 is surrounded by six deformable side walls 5, and the side wall 5 is polarized in the direction of the ink flow path 4 (direction perpendicular to the paper surface in the drawing), and A driving electric field is applied through the electrode 6 in the thickness direction. Since the polarization direction and the driving electric field direction are orthogonal to each other, the six side walls 5 are deformed inside the ink flow path 4 by the deformation of the piezoelectric thickness sliding mode, and the ink pressure in the ink flow path 4 is increased. A droplet is ejected from an orifice (not shown). As described above, this liquid droplet ejecting apparatus is provided with a plurality of through holes in the piezoelectric element, is polarized in the through direction, and is provided with a driving electrode on the surface of the through holes, thereby making the head multi-, high-resolution, and compact. Achieving a simple structure and reducing manufacturing costs.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、前記従
来の液滴噴射装置（特願平３−５４６６９号）は、圧電
セラミックスからなるインク流路の側壁の形状に応じて
必要駆動電圧が大きく変化するという問題点がある。例
えば、前記図５に示した従来例の場合、６個の側壁５が
駆動時に共通のインク流路４内側に変形する際に、隣合
う側壁５同志の接点（インク流路４の正六角形断面の頂
点部分）が殆ど当該インク流路４内側に変形せず、固定
端となるため側壁５を厚みすべり変形させるには高い駆
動電圧が必要となってしまう。However, in the above-mentioned conventional liquid droplet ejecting apparatus (Japanese Patent Application No. 3-54669), the required driving voltage greatly changes depending on the shape of the side wall of the ink flow path made of piezoelectric ceramics. There is a problem. For example, in the case of the conventional example shown in FIG. 5, when the six side walls 5 are deformed to the inside of the common ink flow path 4 at the time of driving, the contacts of the adjacent side walls 5 (regular hexagonal cross section of the ink flow path 4). The apex) of the side wall is hardly deformed to the inside of the ink flow path 4 and becomes a fixed end, so that a high driving voltage is required to cause the side wall 5 to undergo the thickness slip deformation.
【０００５】かかる問題点を解決する手段として固定端
間距離を長くすること、即ち、流路方向に対して垂直方
向に側壁を長くすることが有効であるが、このようにす
るとオリフィス間距離が増大し、印字の解像度が低下し
たり、側壁の強度が下がり装置の信頼性が低くなるとい
う問題点が発生する。As a means for solving such a problem, it is effective to lengthen the distance between the fixed ends, that is, to lengthen the side wall in the direction perpendicular to the flow channel direction. However, there is a problem in that the printing resolution is lowered, the printing resolution is lowered, the side wall strength is lowered, and the reliability of the apparatus is lowered.
【０００６】そこで本発明は上記問題点を解決するため
になされたものであり、強度および信頼性が高く、か
つ、低電圧で駆動可能な高解像度で製造コストの低い液
滴噴射装置を提供することを目的とする。Therefore, the present invention has been made to solve the above problems, and provides a droplet ejection apparatus having high strength and reliability, capable of being driven at a low voltage, and having a high resolution and a low manufacturing cost. The purpose is to
【０００７】[0007]
【課題を解決するための手段】本発明は上記目的を達成
するために、圧電トランスデューサの分極方向と平行に
複数のインク流路を形成し、個々のインク流路における
分極方向と垂直に駆動電界を印加することにより前記圧
電トランスデューサを変形して前記インク流路の容積を
変化せしめ、前記インク流路中に滞留されたインクを噴
射するようにした液滴噴射装置であって、隣接したイン
ク流路間の圧電トランスデューサがなす側壁の横断面形
状における幅方向をなす駆動電界方向長さＷ、前記側壁
の長手方向をなす長さＬ、前記側壁の深さをなす分極方
向長さＨ、とした場合に、前記側壁は、Ｈ≧ＬおよびＬ
／Ｗ≧３になるように構成した。In order to achieve the above object, the present invention forms a plurality of ink flow paths in parallel with the polarization direction of a piezoelectric transducer, and drives an electric field perpendicular to the polarization direction in each ink flow path. A liquid droplet ejecting apparatus configured to deform the piezoelectric transducer by applying a force to change the volume of the ink flow path and to eject the ink retained in the ink flow path. A length W of the driving electric field in the width direction, a length L of the longitudinal direction of the side wall, and a length H of the polarization direction forming the depth of the side wall in the transverse cross-sectional shape of the side wall formed by the piezoelectric transducer between the paths. Where the sidewalls are H ≧ L and L
/ W ≧ 3.
【０００８】[0008]
【作用】本発明によれば、例えば、図２（Ｂ）に示すよ
うに分極方向に平行にインク流路を直方体状に形成し、
隣接した直方体間の圧電トランスデューサがなす側壁の
各辺の長さを分極方向（深さ）Ｈ、駆動電界方向（幅）
Ｗ、分極方向と駆動電界方向の双方に垂直方向（長手方
向の幅）Ｌとする。そして、深さＨ≧長手方向の幅Ｌに
しているのでインクの噴出方向が一定となり、また幅Ｗ
を小さくしているので解像度を低下させることがなく、
長手方向の幅Ｌ／短辺の幅Ｗ≧３にしているので側壁の
「くの字」変形を比較的大きくとれ、比較的大きなイン
ク流路の容積変化が得られる。例えば、Ｌ／Ｗ＝４の場
合に約９０ｐｌの液滴を噴射する駆動電圧は４３Ｖであ
り、低い実用的な電圧で大きな液滴噴射量を得ることが
できる。According to the present invention, for example, as shown in FIG. 2B, the ink flow path is formed in a rectangular parallelepiped shape in parallel with the polarization direction,
The length of each side of the side wall formed by the piezoelectric transducer between adjacent rectangular parallelepipeds is the polarization direction (depth) H, the driving electric field direction (width)
W, the direction L (width in the longitudinal direction) perpendicular to both the polarization direction and the driving electric field direction. Since the depth H ≧ the width L in the longitudinal direction, the ejection direction of the ink is constant, and the width W
Since it is small, there is no reduction in resolution,
Since the width L in the longitudinal direction / the width W of the short side ≧ 3, the “doglegged” deformation of the side wall can be relatively large, and a relatively large volume change of the ink flow path can be obtained. For example, when L / W = 4, the drive voltage for ejecting droplets of about 90 pl is 43 V, and a large droplet ejection amount can be obtained with a low practical voltage.
【０００９】[0009]
【実施例】以下、本発明を図示の実施例に基づいて説明
する。なお、図５で説明した部分と同一部分および均等
部分には同一符号を付し、重複記載を省略する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. It should be noted that the same parts and equivalent parts as those described in FIG. 5 are designated by the same reference numerals, and duplicate description will be omitted.
【００１０】図１（Ａ）に圧電式液滴噴射装置に用いる
アレイ１の断面図を示し、図１（Ｂ）に図１（Ａ）にお
けるＸ−Ｘ線に沿う縦断面図を示す。図１（Ａ）、
（Ｂ）に示すように、アレイ１は、矢印２６方向に分極
処理を施し、かつ、縦１．０ｍｍ、横０．２５ｍｍの長
方形断面の貫通孔を中心間距離０．５ｍｍで横方向（ア
レイ方向）に４個、縦方向に２列に配置した厚さ１．５
ｍｍの上部圧電セラミックス板２と、矢印２８方向に分
極処理を施し、かつ、前記上部圧電セラミックス板２と
同様に縦１．０ｍｍ、横０．２５ｍｍの長方形断面の貫
通孔を中心間距離０．５ｍｍで横方向（アレイ方向）に
４個、縦方向に２列に配置した厚さ１．５ｍｍの下部圧
電セラミックス板３とを、接合してなる。ここに前記貫
通孔により形成されるインク流路４の流路長さは３．０
ｍｍ、流路を分ける両圧電セラミックス板２、３の側壁
５、７の横方向（アレイ方向）寸法は０．２５ｍｍであ
る。FIG. 1A shows a sectional view of the array 1 used in the piezoelectric liquid droplet ejecting apparatus, and FIG. 1B shows a longitudinal sectional view taken along the line XX in FIG. 1A. FIG. 1 (A),
As shown in (B), the array 1 is polarized in the direction of the arrow 26, and the through holes having a rectangular cross section of 1.0 mm in length and 0.25 mm in width are arranged in the lateral direction (array Direction), and a thickness of 1.5 arranged in two rows in the vertical direction
The upper piezoelectric ceramics plate 2 having a rectangular cross section of 1.0 mm in length and 0.25 mm in width has a center-to-center distance of 0. The lower piezoelectric ceramics plate 3 having a thickness of 1.5 mm, which is arranged in two rows in the vertical direction, is bonded to four pieces in a horizontal direction (array direction) of 5 mm. The flow path length of the ink flow path 4 formed by the through hole is 3.0.
mm, the lateral dimension (array direction) of the side walls 5 and 7 of the piezoelectric ceramic plates 2 and 3 that divide the flow path is 0.25 mm.
【００１１】全てのインク流路４の内壁表面には電極６
を形成し、更に電極６の表面はインクとの絶縁のための
絶縁処理を施してある。また、上部圧電セラミックス板
２の上部表面には各インク流路４に対応するオリフィス
１０を有するオリフィスプレート８、下部圧電セラミッ
クス板３の下部表面には、各インク流路４に対応する図
示しないインク供給装置に連結するインク供給路１３を
有する底プレート１２が接合されている。噴射装置３４
は、液滴を噴射するオリフィス１０と、インク流路４
と、インク供給路１３と、流路内容積を変化させインク
に圧力を与えるための圧電セラミックス板２、３からな
り、アレイ１は８個の噴射装置３４を有する圧電式液滴
噴射装置を構成している。Electrodes 6 are provided on the inner wall surfaces of all ink flow paths 4.
And the surface of the electrode 6 is subjected to an insulation treatment for insulation from ink. Further, on the upper surface of the upper piezoelectric ceramics plate 2, the orifice plate 8 having the orifices 10 corresponding to the respective ink flow paths 4, and on the lower surface of the lower piezoelectric ceramics plate 3, the inks not shown corresponding to the respective ink flow paths 4 are shown. A bottom plate 12 having an ink supply path 13 connected to a supply device is joined. Injection device 34
Is an orifice 10 for ejecting droplets and an ink flow path 4
And an ink supply path 13 and piezoelectric ceramic plates 2 and 3 for changing the volume of the flow path and applying pressure to the ink, and the array 1 constitutes a piezoelectric droplet ejecting device having eight ejecting devices 34. is doing.
【００１２】次に図２（Ａ）、（Ｂ）に基づいて前記ア
レイ１の製造方法を説明する。図２（Ａ）に示すよう
に、先ず強誘電性を有するチタン酸ジルコン酸鉛（ＰＺ
Ｔ）系のセラミック材料により、前記インク流路４を形
成する貫通孔を有する圧電セラミックス板２、３の成形
体を射出成形により作成する。前記射出成形後、脱脂工
程・焼結工程・板の厚み方向への分極処理・無電解銅
（またはニッケル）めっき処理による電極形成・電極の
絶縁処理を行う。次いで、点線Ｗに沿った切断工程と、
圧電セラミックス板上下表面に付着した余分な電極を除
き、かつ、平面度を良好にするための上下端面加工を経
て圧電セラミックス２、３を得る。かかる場合に成形法
としては押出し成形法、或いは予め焼結した圧電セラミ
ックス板に機械加工により孔を穿設してもよい。また、
電極形成法として銅またはニッケルのスパッタ法（孔の
内部表面に電極形成のために前記孔の軸と金属原子の平
行ビームとを傾斜させるとよい）を用いても同様な圧電
セラミックス板２、３が得られる。Next, a method for manufacturing the array 1 will be described with reference to FIGS. 2 (A) and 2 (B). As shown in FIG. 2A, first, lead zirconate titanate (PZ) having ferroelectricity is used.
A molded body of the piezoelectric ceramic plates 2 and 3 having through holes that form the ink flow path 4 is made of a T) -based ceramic material by injection molding. After the injection molding, a degreasing step, a sintering step, a polarization treatment in the thickness direction of the plate, an electrode formation by electroless copper (or nickel) plating treatment, and an insulation treatment of the electrode are performed. Then, a cutting process along a dotted line W,
Excessive electrodes attached to the upper and lower surfaces of the piezoelectric ceramic plate are removed, and the upper and lower end surfaces are processed to improve flatness to obtain piezoelectric ceramics 2 and 3. In such a case, the forming method may be an extrusion forming method, or holes may be formed in a piezoelectric ceramic plate that has been sintered in advance by machining. Also,
The same piezoelectric ceramic plates 2 and 3 may be formed by using a copper or nickel sputtering method (it is preferable to incline the axis of the hole and a parallel beam of metal atoms to form an electrode on the inner surface of the hole) as the electrode forming method. Is obtained.
【００１３】このようにして得た上部圧電セラミックス
板２と下部圧電セラミックス板３と、各インク流路に対
応するオリフィス１０を形成したオリフィスプレート８
と、各インク流路４に対応するインク供給路１３を形成
し且つ流路内の電極と駆動用ＬＳＩチップ１６とを電気
的に連結するための配線を下部表面に施した底プレート
１２とを、圧電セラミックス板２、３の分極が低下しな
いように当該圧電セラミックス板２、３のキュリー温度
より十分低い温度で接合する。この接合後、駆動用ＬＳ
Ｉチップ１６を装着してアレイ１が得られる。The upper piezoelectric ceramic plate 2 and the lower piezoelectric ceramic plate 3 thus obtained, and the orifice plate 8 in which the orifices 10 corresponding to the respective ink flow paths are formed.
And a bottom plate 12 on the lower surface of which a wiring for forming an ink supply passage 13 corresponding to each ink passage 4 and electrically connecting an electrode in the passage and the driving LSI chip 16 is provided. , The piezoelectric ceramic plates 2 and 3 are bonded at a temperature sufficiently lower than the Curie temperature of the piezoelectric ceramic plates 2 and 3 so as not to lower the polarization. After this joining, drive LS
The array 1 is obtained by mounting the I-chip 16.
【００１４】前述のようにして得られたアレイ１に、図
３（Ｂ）に示すような電気回路を設ける。この電気回路
において前記切断工程により得られた表面の電極６ｅは
全て接地されている。電極６ａ〜６ｄがそれぞれ別々に
駆動用ＬＳＩチップ１６に接続され、クロックライン１
８、データライン２０、電圧ライン２２およびアースラ
イン２４も駆動用ＬＳＩチップ１６に接続されている。The array 1 obtained as described above is provided with an electric circuit as shown in FIG. In this electric circuit, all the electrodes 6e on the surface obtained by the cutting step are grounded. The electrodes 6a to 6d are separately connected to the driving LSI chip 16, and the clock line 1
8, the data line 20, the voltage line 22, and the ground line 24 are also connected to the driving LSI chip 16.
【００１５】インク流路４は前記図１（Ａ）に示したよ
うに互いに隣合わないＡ、Ｂのグループに分けられ、ク
ロックライン１８から供給された連続するクロックパル
スがこのＡ、Ｂのグループを順次駆動する。データライ
ン２０上に現れる多ビット・ワード形式のデータが各グ
ループの内、どのインク流路４を作動すべきかを決定
し、駆動用ＬＳＩチップ１６の回路により選択されたグ
ループのインク流路４の電極６に電圧ライン２２の電圧
Ｖを印加する。このとき作動されていない同一グループ
のインク流路４の電極６と、他のグループに属する全て
のインク流路４の電極６は接地される。これにより選択
されたインク流路４と隣合うインク流路４の各々に電極
間に両圧電セラミックス板２、３の分極方向と垂直な方
向に電界が印加され、電界の印加された両圧電セラミッ
クス板２、３の流路壁が圧電厚みすべり効果に基づく変
形をなし、前記選択されたインク流路４の容積を変化さ
せる。従って各グループにおいて全てのインク流路４が
作動可能になる。The ink flow path 4 is divided into groups A and B which are not adjacent to each other as shown in FIG. 1A, and continuous clock pulses supplied from the clock line 18 are the groups A and B. Are sequentially driven. The data of the multi-bit word format appearing on the data line 20 determines which ink flow path 4 of each group should be operated, and the ink flow path 4 of the group selected by the circuit of the driving LSI chip 16 is selected. The voltage V of the voltage line 22 is applied to the electrode 6. At this time, the electrodes 6 of the ink channels 4 of the same group which are not operated and the electrodes 6 of all the ink channels 4 belonging to other groups are grounded. As a result, an electric field is applied between the electrodes of each of the ink flow paths 4 adjacent to the selected ink flow path 4 in the direction perpendicular to the polarization direction of the piezoelectric ceramic plates 2 and 3, and the piezoelectric ceramics to which the electric field is applied. The flow path walls of the plates 2 and 3 are deformed based on the piezoelectric thickness sliding effect, and the volume of the selected ink flow path 4 is changed. Therefore, all the ink flow paths 4 can be operated in each group.
【００１６】次に、図３（Ａ）、（Ｂ）に基づき所定の
印字データにより噴射装置３４ｂが選択された場合の噴
射装置の動作を説明する。図３（Ａ）はアレイ１の断面
図でありインク流路４の断面を示し、図３（Ｂ）は図３
（Ａ）におけるＸ1 −Ｘ1 線に沿う縦断面図である。Next, the operation of the ejection device when the ejection device 34b is selected by the predetermined print data will be described with reference to FIGS. 3 (A) and 3 (B). 3A is a cross-sectional view of the array 1 showing a cross section of the ink flow path 4, and FIG.
It is a longitudinal sectional view taken along the X 1 -X 1 line in (A).
【００１７】図３（Ａ）、（Ｂ）に示すように、インク
流路４ｂ内の電極６ｂに電圧ライン２２の電圧Ｖが印加
され、他の電極６ａ、６ｃを始めとするインク流路４ｂ
と隣合うインク流路４の電極６は全て接地され、側壁５
ｂ、７ｂ、５ｃ、７ｃを始めとするインク流路４ｂを囲
む側壁５、７に矢印３２方向に駆動電界が印加される。
駆動電界と分極方向とが直交しているため圧電厚み効果
の変形により側壁５ｂ、７ｂ、５ｃ、７ｃを始めとする
インク流路４ｂを囲む側壁５、７が「くの字」にインク
流路４ｂの内側に向かって変形する。この変形によりイ
ンク流路４ｂの容積が減少し、インクがオリフィス１０
ｂから噴射される。また、電圧の印加が遮断され側壁５
ｂ、７ｂ、５ｃ、７ｃを始めとするインク流路４ｂを囲
む側壁５、７が元の位置まで戻されると、その際のイン
ク流路４ｂの容積増加に伴いインク供給路１３ｂを経て
図示しないインク供給装置からインクが補充される。な
お、例えば他の噴射装置３４ｃが選択された場合は、側
壁５ｃ、７ｃ、５ｄ、７ｄを始めとするインク流路４ｃ
を囲む側壁５、７が「くの字」にインク流路４ｃ内側に
向かって変形し、インク流路４ｃ内のインクが噴射され
る。As shown in FIGS. 3A and 3B, the voltage V of the voltage line 22 is applied to the electrode 6b in the ink flow path 4b, and the ink flow path 4b including the other electrodes 6a and 6c.
All the electrodes 6 of the ink flow path 4 adjacent to the
A driving electric field is applied in the direction of arrow 32 to the side walls 5 and 7 surrounding the ink flow path 4b including b, 7b, 5c and 7c.
Since the driving electric field and the polarization direction are orthogonal to each other, the piezoelectric thickness effect is deformed so that the side walls 5 and 7 surrounding the ink flow path 4b including the side walls 5b, 7b, 5c, and 7c have a "doglegged" ink flow path. It deforms toward the inside of 4b. Due to this deformation, the volume of the ink flow path 4b is reduced, and the ink flows into the orifice 10.
It is injected from b. In addition, the application of voltage is blocked and the side wall 5
When the side walls 5 and 7 surrounding the ink flow path 4b including b, 7b, 5c and 7c are returned to their original positions, the volume of the ink flow path 4b at that time increases and the ink supply path 13b is not shown. Ink is replenished from the ink supply device. In addition, for example, when another ejection device 34c is selected, the ink flow path 4c including the side walls 5c, 7c, 5d, and 7d.
The side walls 5 and 7 surrounding the are deformed toward the inside of the ink flow path 4c in a "dogleg" shape, and the ink in the ink flow path 4c is ejected.
【００１８】ここで、図４（Ａ）、（Ｂ）に基づいて厚
みすべりモードによる変形について説明する。図４
（Ａ）は基盤４１に固定した壁４０の斜視図であり、こ
の壁４０の分極方向２８における寸法を高さＨ、一対の
電極４２により印加される駆動電界方向における寸法を
厚さＷ、分極方向２８と駆動電界方向の双方に垂直な方
向の寸法を長さＬとした場合に、駆動電界方向が図中右
向きであるときに点線Ｔで示すように、壁４０は図中左
向きに剪断変形する。この剪断変形により前述の如くイ
ンク流路４の容積を変化させる場合、その容積変化量は
厚さＷと駆動電圧を一定としたとき、長さＬに比例し、
高さＨの２乗に比例するので容積変化量を増加するには
高さＨをより高くした方が有利である。Here, the deformation due to the thickness sliding mode will be described with reference to FIGS. 4 (A) and 4 (B). Figure 4
(A) is a perspective view of a wall 40 fixed to a substrate 41, in which the dimension in the polarization direction 28 of this wall 40 is height H, the dimension in the driving electric field direction applied by a pair of electrodes 42 is thickness W, and the polarization is When the dimension in the direction perpendicular to both the direction 28 and the driving electric field direction is length L, the wall 40 is sheared to the left in the drawing as indicated by a dotted line T when the driving electric field direction is to the right in the drawing. To do. When the volume of the ink flow path 4 is changed by the shear deformation as described above, the volume change amount is proportional to the length L when the thickness W and the driving voltage are constant,
Since it is proportional to the square of the height H, it is advantageous to make the height H higher in order to increase the volume change amount.
【００１９】また、図４（Ｂ）は前記壁４０を長さＬ方
向の両端部４４において横基盤４３に固定した場合の平
面図であり、実際に液滴噴射装置のアレイ１に応用する
場合には図示の構成となる。この場合の変形は点線Ｔ1
により示すように、両端部４４を固定端として壁４０が
変形方向に反った形状となり、前記図４（Ａ）で示した
長さＬ方向の両端部がフリーの場合に比較し、壁４０に
働く応力の分だけ余分なエネルギ（駆動電圧）を必要と
する。この余分に必要な駆動電圧はＬ／Ｗ比が大きいほ
ど少なくなる。計算によれば長さ方向の両端部４４を固
定した場合に或る容積変化を得るために、両端部フリー
の場合に比較しＬ／Ｗ＝１のとき数１００倍になり、Ｌ
／Ｗ＝２のとき数１０倍にもなるが、Ｌ／Ｗが３以上に
なると数倍〜１０倍程度になることが確認された。FIG. 4B is a plan view of the wall 40 fixed to the horizontal base 43 at both ends 44 in the length L direction, and is actually applied to the array 1 of the liquid droplet ejecting apparatus. The configuration shown in FIG. The deformation in this case is the dotted line T1
As shown by, the wall 40 has a shape in which the both ends 44 are fixed ends and is warped in the deformation direction, and the wall 40 has a wall 40 in comparison with the case where both ends in the length L direction shown in FIG. 4A are free. Extra energy (driving voltage) is required for the stress applied. The extra drive voltage required decreases as the L / W ratio increases. According to the calculation, in order to obtain a certain volume change when the both end portions 44 in the length direction are fixed, when L / W = 1, it becomes several hundred times larger than that in the case where both end portions are free.
It was confirmed that when / W = 2, it increased several tens of times, but when L / W became 3 or more, it increased several times to 10 times.
【００２０】そのため少なくともＬ／Ｗの比は３以上は
必要である。但し、Ｌ／Ｗの比が大きすぎると圧電セラ
ミックス２、３にＬ方向に非常に細長い側壁５、７（図
３参照）を設ける必要があり、射出成形法による成形
時、機械加工による穴開け加工時、あるいは駆動時の強
度・信頼性が著しく低下するため、好ましくはＬ／Ｗ≦
１０とするのがよい。即ち、より効率よく壁４０を厚み
すべりモードで変形させるには、分極方向の寸法Ｈ、厚
み寸法Ｗ、分極方向と厚み方向の双方に垂直となる方向
の寸法Ｌとした場合に、高さＨを最も大きくし、更にＬ
／Ｈ比が３以上になるようにすればよい。Therefore, at least the L / W ratio must be 3 or more. However, if the L / W ratio is too large, the piezoelectric ceramics 2 and 3 need to be provided with very long side walls 5 and 7 (see FIG. 3) in the L direction, and during molding by the injection molding method, holes are formed by machining. Since strength / reliability during processing or driving is significantly reduced, L / W ≦
A value of 10 is good. That is, in order to more efficiently deform the wall 40 in the thickness-sliding mode, the height H is set to the dimension H in the polarization direction, the thickness dimension W, and the dimension L in the direction perpendicular to both the polarization direction and the thickness direction. Is made the largest, and further L
The / H ratio may be set to 3 or more.
【００２１】本実施例の液滴噴射装置のアレイ１は１つ
のインク流路４を囲む側壁５、７が合計４個であり、各
々の側壁５、７はＨ＝１．５ｍｍ、Ｌ＝１．０ｍｍ、Ｗ
＝０．２５ｍｍであり、Ｈが最大で、Ｌ／Ｗ＝４である
ので前記条件を満たしている。このとき約９０ｐｌの液
滴を噴射するための駆動電圧は４３Ｖであった。比較例
としてＨとＷ、およびオリフィス１０のアレイ方向のピ
ッチを一定としＬを変えＬ／Ｗ比を２．６〜３．６まで
変えた場合の駆動電圧は３７３Ｖ（Ｌ／Ｗ＝２．６）、
２５７Ｖ（Ｌ／Ｗ＝２．８）、１８２Ｖ（Ｌ／Ｗ＝
３）、１３２Ｖ（Ｌ／Ｗ＝３．２）、９７Ｖ（Ｌ／Ｗ＝
３．４）、７３Ｖ（Ｌ／Ｗ＝３．６）となりＬ／Ｗ比が
３より小さい場合には駆動電圧が２００Ｖを越えてしま
い実用的でない。The array 1 of the droplet ejecting apparatus of this embodiment has a total of four side walls 5 and 7 surrounding one ink flow path 4, and each side wall 5 and 7 is H = 1.5 mm and L = 1. 0.0 mm, W
= 0.25 mm, H is maximum, and L / W = 4, the above conditions are satisfied. At this time, the driving voltage for ejecting a droplet of about 90 pl was 43V. As a comparative example, the driving voltage when H and W and the pitch of the orifices 10 in the array direction are fixed and L is changed to change the L / W ratio from 2.6 to 3.6, the drive voltage is 373 V (L / W = 2.6). ),
257V (L / W = 2.8), 182V (L / W =
3), 132V (L / W = 3.2), 97V (L / W =
3.4), 73V (L / W = 3.6), and when the L / W ratio is smaller than 3, the driving voltage exceeds 200V, which is not practical.
【００２２】更にこのとき、どの場合もアレイ方向のオ
リフィス１０のピッチが一定であるということは、逆に
いえば本発明によれば印字の解像度を低下させずに低電
圧駆動化が実現でき、更にアレイ方向に垂直な方向への
側壁５、７の長さＬについても分極方向への高さＨを大
きくすることで最小限に押さえることができる。Further, at this time, in any case, the pitch of the orifices 10 in the array direction is constant. Conversely, according to the present invention, low voltage driving can be realized without lowering the printing resolution. Further, the length L of the side walls 5 and 7 in the direction perpendicular to the array direction can be minimized by increasing the height H in the polarization direction.
【００２３】以上説明したように、本実施例の圧電式液
滴噴射装置においては、８個の噴射装置３４を駆動する
ための圧電トランスデューサが２枚の圧電セラミックス
板２、３からなり、アレイ１の構造が簡略化されている
ので、アレイ１、更にアレイ１を多数組み付けることに
より圧電式液滴噴射装置の製造工程が少なくなり、製造
コストも低減される。また、圧電セラミックス２、３に
貫通孔からなるインク流路４を多数密集させることによ
り、噴射装置３４の数の増加、アレイ１の小形化、印字
の解像度の向上、駆動電圧の低減を図ることができる。As described above, in the piezoelectric droplet ejecting apparatus of this embodiment, the piezoelectric transducer for driving the eight ejecting apparatuses 34 is composed of the two piezoelectric ceramic plates 2 and 3, and the array 1 is used. Since the structure of (1) is simplified, by assembling the array 1 and further a large number of arrays 1, the number of manufacturing steps of the piezoelectric type droplet jetting device is reduced and the manufacturing cost is also reduced. Further, by densely packing a large number of ink flow paths 4 formed of through holes in the piezoelectric ceramics 2 and 3, it is possible to increase the number of ejecting devices 34, downsize the array 1, improve printing resolution, and reduce driving voltage. You can
【００２４】例えば、本実施例と同一寸法のインク流路
４を同一の中心距離で６４個（縦２×横３２）に配置し
た場合のアレイ１の外形寸法は２．２ｍｍ×１６．２ｍ
ｍ×５ｍｍ以下でよい。また、本実施例の場合、側壁の
分極方向の寸法をＨ、厚み寸法をＷ、分極方向と厚み方
向の双方に垂直である方向の寸法をＬとしたときに、Ｈ
≧Ｌ且つＬ／Ｗ≧３であるように側壁の形状を最適に選
択したため、側壁の強度と信頼性および印字の解像度を
低下させずに４３Ｖという低駆動電圧で約９０ｐｌのイ
ンク液滴を噴射することができ、従来約１２０〜１７０
Ｖの駆動電圧が必要とされていたものを大幅な低電圧駆
動化を実現した。For example, when the ink channels 4 having the same dimensions as those of the present embodiment are arranged in 64 pieces (2 vertical × 32 horizontal) at the same center distance, the outer dimensions of the array 1 are 2.2 mm × 16.2 m.
It may be m × 5 mm or less. Further, in the case of the present embodiment, when the dimension of the side wall in the polarization direction is H, the thickness dimension is W, and the dimension in the direction perpendicular to both the polarization direction and the thickness direction is L, H
Since the side wall shape is optimally selected so that ≧ L and L / W ≧ 3, ink droplets of about 90 pl are ejected at a low driving voltage of 43 V without lowering the strength and reliability of the side wall and the resolution of printing. Can be done conventionally about 120-170
We have realized a drastic reduction in the voltage that required a V drive voltage.
【００２５】なお、本実施例ではインク流路の断面形状
を長方形としたが、短辺に丸みを付けた小判形状でもよ
い。このようにすれば、射出成形および機械加工による
流路形成が容易になり、また駆動時の応力集中が減少し
信頼性の向上に寄与する。In this embodiment, the cross section of the ink flow path is rectangular, but it may be oval with a rounded short side. This facilitates formation of the flow path by injection molding and machining, and reduces stress concentration during driving, which contributes to improvement in reliability.
【００２６】[0026]
【発明の効果】以上説明したように本発明によれば、イ
ンク流路間に形成される側壁の分極方向の寸法をＨ、厚
み寸法をＷ、分極方向と厚み方向の双方に垂直である方
向の寸法をＬとした場合に、Ｈ≧Ｌ且つＬ／Ｗ≧３とし
てインク流路を構成したので、印字の解像度を良好に保
ち、かつ、インク流路の形成加工が容易であり、駆動電
圧の低い液滴噴射装置を提供することができる。As described above, according to the present invention, the side wall formed between ink flow paths has a dimension H in the polarization direction, a thickness dimension W, and a direction perpendicular to both the polarization direction and the thickness direction. Since the ink flow path is configured so that H ≧ L and L / W ≧ 3 when the dimension of L is L, the printing resolution can be kept good, and the formation and processing of the ink flow path can be facilitated. Thus, it is possible to provide a liquid droplet ejecting apparatus having a low cost.
【図１】（Ａ）は本発明の実施例に使用するアレイの断
面図、（Ｂ）は前記アレイのＸ−Ｘ線に沿う断面図であ
る。FIG. 1A is a sectional view of an array used in an embodiment of the present invention, and FIG. 1B is a sectional view taken along line XX of the array.
【図２】（Ａ）は前記アレイに使用する圧電セラミック
ス板の正面図、（Ｂ）は前記アレイの分解斜視図であ
る。FIG. 2A is a front view of a piezoelectric ceramic plate used for the array, and FIG. 2B is an exploded perspective view of the array.
【図３】（Ａ）は前記アレイの駆動状態の断面図、
（Ｂ）は（Ａ）におけるＸ1 −Ｘ1線に沿う断面の駆動
状態を示す図である。FIG. 3A is a sectional view of a driving state of the array,
(B) is a diagram showing a driving state of a cross section taken along line X1-X1 in (A).
【図４】（Ａ）は圧電厚みすべりモードによる壁の変形
を示す斜視図、（Ｂ）は圧電厚みすべりモードによる両
端固定の壁の変形を示す平面図である。FIG. 4A is a perspective view showing deformation of a wall due to a piezoelectric thickness sliding mode, and FIG. 4B is a plan view showing deformation of a wall fixed at both ends due to a piezoelectric thickness sliding mode.
【図５】従来の液滴噴射装置を構成するアレイの断面図
である。FIG. 5 is a cross-sectional view of an array that constitutes a conventional droplet ejection device.
１…アレイ ２…上部圧電セラミックス（圧電トランスデューサ） ３…下部圧電セラミックス（圧電トランスデューサ） ４…インク流路 ５、７…側壁 ６…電極 １０…オリフィス １３…インク供給路 ２６、２８…分極方向 ３４…噴射装置 Ｈ…インク流路の深さをなす分極方向長さ Ｗ…インク流路の横断面形状における幅方向をなす駆動
電界方向の長さ Ｌ…インク流路の横断面形状における長手方向をなす長
さ1 ... Array 2 ... Upper piezoelectric ceramics (piezoelectric transducer) 3 ... Lower piezoelectric ceramics (piezoelectric transducer) 4 ... Ink flow path 5, 7 ... Side wall 6 ... Electrode 10 ... Orifice 13 ... Ink supply path 26, 28 ... Polarization direction 34 ... Ejection device H ... Polarization direction length that forms the depth of the ink flow path W ... Length in the driving electric field direction that forms the width direction in the cross section shape of the ink flow path L ... Makes the longitudinal direction in the cross section shape of the ink flow path length
Claims (1)
に複数のインク流路を形成し、個々のインク流路におけ
る分極方向と垂直に駆動電界を印加することにより前記
圧電トランスデューサを変形して前記インク流路の容積
を変化せしめ、前記インク流路中に滞留されたインクを
噴射するようにした液滴噴射装置であって、 隣接したインク流路間の圧電トランスデューサがなす側
壁の横断面形状における幅方向をなす駆動電界方向長さ
Ｗ、前記側壁の長手方向をなす長さＬ、前記側壁の深さ
をなす分極方向長さＨ、とした場合に、前記側壁は、Ｈ
≧ＬおよびＬ／Ｗ≧３になるように構成されていること
を特徴とする液滴噴射装置。1. A plurality of ink flow paths are formed in parallel with the polarization direction of the piezoelectric transducer, and a driving electric field is applied perpendicularly to the polarization direction in each ink flow path to deform the piezoelectric transducer to transform the ink flow. A droplet ejecting device that ejects the ink retained in the ink flow passage by changing the volume of the passage, and is a width direction in a lateral cross-sectional shape of a side wall formed by piezoelectric transducers between adjacent ink flow passages. When the length W of the driving electric field in the direction L, the length L of the side wall in the longitudinal direction, and the length H of the polarization direction in the depth of the side wall are H,
A droplet jetting device, characterized in that ≧ L and L / W ≧ 3.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21546191A JP3024291B2 (en) | 1991-08-27 | 1991-08-27 | Droplet ejector |
| US07/852,542 US5245244A (en) | 1991-03-19 | 1992-03-17 | Piezoelectric ink droplet ejecting device |
| EP92302387A EP0505188B1 (en) | 1991-03-19 | 1992-03-19 | Piezoelectric ink droplet ejecting device |
| DE69203901T DE69203901T2 (en) | 1991-03-19 | 1992-03-19 | Piezoelectric device for generating a jet from ink droplets. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21546191A JP3024291B2 (en) | 1991-08-27 | 1991-08-27 | Droplet ejector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0550599A true JPH0550599A (en) | 1993-03-02 |
| JP3024291B2 JP3024291B2 (en) | 2000-03-21 |
Family
ID=16672761
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21546191A Expired - Lifetime JP3024291B2 (en) | 1991-03-19 | 1991-08-27 | Droplet ejector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3024291B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6133484A (en) * | 1985-04-01 | 1986-02-17 | 株式会社日立製作所 | Constraint mechanism of cage door for elevator |
| US7988263B2 (en) | 2007-03-08 | 2011-08-02 | Fuji Xerox Co., Ltd. | Liquid droplet ejection head, liquid droplet ejection device, and image forming apparatus |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102186233B1 (en) | 2019-02-20 | 2020-12-03 | 충남대학교산학협력단 | Composition for removing odor from livestock manure comprising humic substance and lactic acid bacteria |
-
1991
- 1991-08-27 JP JP21546191A patent/JP3024291B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6133484A (en) * | 1985-04-01 | 1986-02-17 | 株式会社日立製作所 | Constraint mechanism of cage door for elevator |
| JPS6216912B2 (en) * | 1985-04-01 | 1987-04-15 | Hitachi Seisakusho Kk | |
| US7988263B2 (en) | 2007-03-08 | 2011-08-02 | Fuji Xerox Co., Ltd. | Liquid droplet ejection head, liquid droplet ejection device, and image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3024291B2 (en) | 2000-03-21 |
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