JP3869786B2 - Ink jet head and manufacturing method thereof - Google Patents

Description

【００３１】
この実験によれば、ギャップが小さいほど圧力波の残留振動の影響が小さくなる傾向があり、逆に、ギャップが大きくなって４０μｍになると、従来構造と同様にインクの噴出特性に影響を及ぼすことがわかった。これは、ギャップがある程度以上大きいと圧力波がチャンネル溝内の空間と狭隙部との界面で反射する量が大きくなることによると考えられる。また、別途実験を行なって、狭隙部の長さＬは、インクジェットヘッドの全長の範囲内で可能な限り長い方が圧力波の残留振動を抑制する効果が大きいことも確認できた。したがって、狭隙部の長さＬを可能な限り長く設定し、ギャップを３０μｍ以下に適宜設定することで圧力波の残留振動の悪影響を抑制できることが確認できた。
【００３２】
（実施の形態２）
（製造方法）
図３〜図１０を参照して、本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法について説明する。このインクジェットヘッドの製造方法は、実施の形態１で説明したインクジェットヘッドを製造するために適用可能な製造方法である。
【００３３】
図３にカバー基板５２を示す。カバー基板５２とは、カバー部材２ｉの材料となる板である。カバー部材２ｉは、カバー基板５２から切り出される。図３は、カバー基板５２の、後に圧電基板５１と貼り合せられる側から見た図である。カバー基板５２から切り出されるカバー部材２ｉは、圧電基板５１と接着されてインク室を構成するものであることから、圧電基板５１とカバー基板５２とは熱膨張率を揃えることが好ましい。また、共通インク室２４ｉを形成する際の加工特性についても圧電基板５１と大差ないものが望ましい。
【００３４】
カバー基板５２は、通常、快削性セラミックス、圧電基板などで構成されている。また、カバー基板５２には、圧電基板５１と接着された時に共通インク室２４ｉを構成するための凹部２１が形成されている。凹部２１は、カバー基板５２にレジストをパターニングして王水でエッチング加工をすることによって形成することができる。凹部２１を形成するための他の方法として、カバー基板５２にドライフィルムレジストをパターニングし、ＳｉＣやＡｌ₂Ｏ₃などの粒子を高圧力で吹き付けるサンドブラスト加工で形成することができる。あるいは、エンドミルやダイシングブレードなどによる研削加工によっても形成することができる。そもそも共通インク室２４ｉの加工深さや加工位置はインク吐出にあまり影響しないため、凹部２１の形成時には高精度な加工は要求されない。
【００３５】
次に、図４に示すように、インクジェットヘッドとなったときにアクティブ領域１２ｉ（図２参照）となる予定の領域３２、およびインク室と対向しないインク封止部分１５の領域に、シリカフィラー１４が分散された接着剤１３を転写供給する。接着剤１３は厚さ３５μｍのフィルム状で所望の形状に型抜きされた状態で転写される。フィルム状の接着剤１３は、図５に示すように、保護フィルム１６に貼られた状態で供給される。保護フィルム１６には接着剤１３の型抜きと同時に位置決め用穴１８が形成されている。図５に示すように、転写ステージ２２上には位置決めピン１７が配置されている。図４、図５に示すように位置決めピン１７は、カバー基板５２の端に当接することによってカバー基板５２の位置を規定する。これと同時に位置決めピン１７は、図５に示すように、位置決め用穴１８に挿入されることによって保護フィルム１６の位置を規定する。その結果、カバー基板５２と保護フィルム１６との位置関係が固定される。
【００３６】
接着剤１３に対して、転写ツール１９を用いて８０℃に加熱しつつ加圧を行なう。その結果、フィルム状の接着剤１３とカバー基板５２とが密着する。その後に保護フィルム１６を剥離する。なお、保護フィルム１６は厚さ１００μｍ以上の厚手ＰＥＴフィルムや強靭なポリイミドフィルムなどで構成することとすれば、位置決め穴などの寸法精度を確保することができる。
【００３７】
ここでは、接着剤をフィルム状であるとしてその供給方法を説明したが、接着剤を供給するための他の方法として、接着剤を液状として供給する方法も考えられる。スペーサ部材を分散した液状の接着剤をメタルマスクなどを利用して印刷することによって供給する。メタルマスクは、メタルマスクに形成した位置決め穴とウエハ位置決めピンとを利用して位置決めされる。メタルマスクを利用する場合は、たとえば、ギャップの大きさが１０μｍ、２０μｍ、３０μｍの狭隙部をそれぞれ形成したいときは、シリカフィラー径を１０μｍ、２０μｍ、３０μｍにそれぞれ設定して、メタルマスクの厚みはシリカフィラー径より若干厚い２０μｍ、３０μｍ、４０μｍとしてそれぞれ印刷する。こうすることで、均一なフィラー分散が実現できるとともに、印刷不良などの欠陥が生じない印刷供給が実現できる。ただし、できれば真空中で印刷が行なえる真空印刷機を用いることが望ましい。このように液状の接着剤を適用する場合は、接着剤供給装置および接着剤供給工程が簡単に実現可能であるので、生産歩留まりが向上して低コスト化を実現することができる。
【００３８】
次に、図６に示すように、圧電基板５１の上面にドライフィルムレジスト２０をラミネートし、その上からチャンネル溝４を、等間隔かつ等幅となるように、ダイシング装置のダイシングブレード２３により形成する。チャンネル溝４は内部空間がインク室となるものである。なお、圧電基板５１はあらかじめ、厚み方向に一定の向きに分極させた圧電材料の板同士を分極の向きが互いに逆になるように貼り合せたものである。この貼合せに用いる板の厚みは、チャンネル溝４を形成したときに、チャンネル溝４の深さ方向のほぼ中間位置に、板同士の境目（図示省略）が露出するように選ばれる。
【００３９】
図７に示すように、チャンネル溝４の内壁に対して、２方向からＡｌ、Ｃｕなどの斜め蒸着を行なうことによりＡｌ、Ｃｕなどの電極５を形成する。電極５を形成するには、斜め蒸着による以外に、スパッタリングやめっきなどによっても可能である。この電極８の形成時には、ドライフィルムレジスト２０上にも金属膜が付着するが、これについてはドライフィルムレジスト２０を剥離することで除去する。こうして、図８に示す構造が得られる。
【００４０】
次に、図９に示すように、ディスペンサ２８などを用いて、チャンネル溝４を横切るように導電性ペーストからなる導電材２６ｕを塗布する。ディスペンサ２８の走査経路がチャンネル溝４に交差する箇所では、導電材２６ｕはチャンネル溝４内に充填される。加熱することで、導電材２６ｕは硬化する。この状態では各インク室の電極５はいずれも電気的につながっていることになる。その後、圧電基板５１上面に載っている導電材２６ｕを研磨除去することによって、各インク室を電気的にそれぞれ分離し、互いの絶縁を確保する。各チャンネル溝４内には、導電材２６ｕが硬化し、チャンネル溝４ごとに分離された形状のものである導電性部材２６が配置された形となる。
【００４１】
次に、フィルム状の接着剤１３が供給されたカバー基板５２（図５参照）と、チャンネル溝４が形成されて電極５が形成されて導電性部材２６が充填されている圧電基板５１とを、図１０に示すように重ねて、加熱および加圧することによって接着剤１３を硬化させて貼り合わせる。接着剤１３を挟み込んで圧電基板５１とカバー基板５２とが対向するところには、接着剤１３の中に含まれるスペーサ部材としてのシリカフィラー１４の存在によって間隙が生じ、この間隙は狭隙部１１ｉとなる。この重ね合わせ基板に対して、図１０に破線で示すダイシングライン２９に沿って、ダイシングブレードで切断を行なう。ダイシングライン２９は、カバー基板５２の凹部２１および圧電基板５１の導電性部材２６の充填部分を通過するように設定されている。この切断により、重ね合わせ基板は、個々のインクジェットヘッド片に分割され、アクチュエータとしてのインクジェットヘッド片が完成する。凹部２１は共通インク室２４ｉとなる。
【００４２】
さらに、前端にノズル板９を貼り付けたり、必要に応じて後端に外部接続端子８を貼り付けたりする。その結果、図１、図２に示すインクジェットヘッドを得ることができる。
【００４３】
（作用・効果）
本実施の形態では、シリカフィラー１４をスペーサ部材として接着剤１３中に混入させることによってベース部材１とカバー部材２ｉとの間に狭隙部１１ｉを構成する方法を採っているので、高精度な切削加工や研削加工を必要とせずに狭隙部を得ることができる。また、シリカフィラー１４の直径を適宜変更することで狭隙部のギャップの大きさを所望の値に変更することができる。
【００４４】
また、スペーサ部材としては、シリカフィラーに代えて、プラスチックフィラーを用いてもよい。プラスチックフィラーを用いた場合はフィラー径を揃えやすい。また、スペーサ部材を分散した接着剤を安価に製造することができ、コスト低減が実現できる。プラスチックフィラーを用いた場合、１通りの直径から複数とおりのギャップの大きさを実現することができる。たとえば、直径３０μｍのプラスチックフィラーを分散させた接着剤を用意するだけで、あとはカバー基板５２と圧電基板５１との接着時に印加する荷重の大きさを適切に選ぶことによってフィラーの潰れ具合を制御し、３０μｍ以下の所望の値のギャップの大きさを任意に設定することができる。
【００４５】
（実施の形態３）
（構成）
実施の形態１，２では、スペーサ部材として球形のシリカフィラー１４を用いたが、スペーサ部材は球形のものに限る必要はない。本発明に基づく実施の形態３では、異なる形状のスペーサ部材を用いた例として、図１１、図１２を参照して、インクジェットヘッド１２１について説明する。図１１は、インクジェットヘッド１２１を正面から見たところを示す。図１２は、図１１のＸＩＩ−ＸＩＩ線に関する矢視断面図である。インクジェットヘッド１２１では、ベース部材１とカバー部材２ｉとは、間に平板状スペーサ部材１９を挟み込むようにして接着されている。平板状スペーサ部材１９としては、ベース部材１やカバー部材２ｉとの線膨張係数の相性を考慮してアルミナセラミックの薄板を用いることができる。他の材料としては、加工性に優れていることから金属薄板やプラスチック薄板を用いることもできる。
【００４６】
（製造方法）
インクジェットヘッド１２１を製造するには、平板状スペーサ部材１９の表裏面もしくは圧電基板５１およびカバー基板５２に接着剤を供給し、平板状スペーサ部材１９を介在させた状態で積み重ねて接着することとすればよい。あるいは、あらかじめ平板状スペーサ部材１９の表裏面にフィルム状接着剤を形成したものを用意して、これを圧電基板５１とカバー基板５２との間に挟み込んで加熱および加圧することによってもよい。いずれも重ね合わせ基板とした後にダイシングブレードなどで分割して個別のインクジェットヘッドを得る点は、実施の形態２と同様である。
【００４７】
（作用・効果）
本実施の形態のようにスペーサ部材として平板状のものを用いた場合にも、狭隙部１１ｉを構成することができるので、実施の形態１と同様の効果が得られる。
【００４８】
本実施の形態においては、インク室内部に向けて接着剤が露出する表面には平板状のスペーサ部材の表面形状がそのまま現れるので、粒子状のスペーサ部材を含む接着剤の場合に比較して、はるかに平滑となる。したがって、インクの流れおよびインク中の気泡の流れがスムーズになり、インク吐出性能を向上させることができる。また、インクジェットヘッドの内部から気泡を排出するためのメンテナンス作業を容易にできるという効果も奏する。
【００４９】
なお、上述の各実施の形態では、圧電方式のインクジェットヘッドの場合について述べた。しかし、インクの噴出原理が異なる他の方式（例えば、サーマルインクジェット方式）のインクジェットヘッドについても、インクの流路の基本構造（インク加圧室、共通インク室）が同じであれば本発明を適用することができる。
【００５０】
なお、今回開示した上記実施の形態はすべての点で例示であって制限的なものではない。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更を含むものである。
【００５１】
【発明の効果】
本発明によれば、カバー部材がベース部材に対してスペーサ部材によって規定される間隙を介して対向する領域は、いわゆる狭隙部として作用し、インクの吐出に伴って生じる圧力波を、吸収、減衰させることができる。しかも、狭隙部の間隙の大きさはスペーサ部材によって規定されるので、高精度な機械加工などが不要であり、所望の大きさの間隙の狭隙部に製作することが容易となる。
【図面の簡単な説明】
【図１】 本発明に基づく実施の形態１におけるインクジェットヘッドの正面図である。
【図２】 本発明に基づく実施の形態１におけるインクジェットヘッドの断面図である。
【図３】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法で用いるカバー基板の平面図である。
【図４】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法で用いるカバー基板に接着剤を塗布した状態の平面図である。
【図５】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法で行なわれる、カバー基板に保護フィルムを押し付ける工程の説明図である。
【図６】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法の第１の工程の説明図である。
【図７】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法の第２の工程の説明図である。
【図８】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法の第３の工程の説明図である。
【図９】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法の第４の工程の説明図である。
【図１０】 本発明に基づく実施の形態２におけるインクジェットヘッドの製造方法の第５の工程の説明図である。
【図１１】 本発明に基づく実施の形態３におけるインクジェットヘッドの正面図である。
【図１２】 本発明に基づく実施の形態３におけるインクジェットヘッドの断面図である。
【図１３】 従来技術に基づくインクジェットヘッドの正面図である。
【図１４】 従来技術に基づくインクジェットヘッドの断面図である。
【図１５】 本発明の参考となるインクジェットヘッドの正面図である。
【図１６】 本発明の参考となるインクジェットヘッドの断面図である。
【符号の説明】
１ ベース部材、２，２ｈ，２ｉ カバー部材、３ チャンネル壁、４ チャンネル溝、５ 電極、８ 外部接続端子、９ ノズル板、１０ ノズル孔、１１，１１ｉ 狭隙部、１２，１２ｉ アクティブ領域、１３ 接着剤、１４ シリカフィラー、１５ インク封止部、１６ 保護フィルム、１７ 位置決めピン、１８ 位置決め用穴、１９ 平板状スペーサ部材、２０ ドライフィルムレジスト、２１ 凹部、２３ ダイシングブレード、２４，２４ｈ 共通インク室、２６ 導電性部材、２６ｕ （固化前の）導電材、２７ インク供給口、２８ ディスペンサ、２９ ダイシングライン、３２ （アクティブ領域となる予定の）領域、５１ 圧電基板、５２ カバー基板。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet head used in a printer or the like and a manufacturing method thereof.
[0002]
[Prior art]
An inkjet printer prints an image on a medium such as paper by ejecting minute droplets of ink in accordance with print data from minute nozzle holes provided in an inkjet head. One of the ink jet head systems is a piezoelectric system.
[0003]
A conventional piezoelectric inkjet head will be described with reference to FIGS. FIG. 13 shows the inkjet head 100 as viewed from the front. A nozzle plate 9 having a plurality of nozzle holes 10 is disposed on the front surface of the inkjet head 100. Corresponding to each of the nozzle holes 10, channel grooves 4 extend in parallel behind the nozzle plate 9. Since the channel groove 4 provided in the base member 1 is closed by the cover member 2, the internal space of the channel groove 4 functions as an ink chamber. Adjacent channel grooves 4 are separated by a channel wall 3. 14 is a cross-sectional view taken along the line XIV-XIV in FIG. As shown in FIG. 14, an electrode 5 is formed on the side surface of the channel wall 3. A conductive member 26 is filled at the rear end (right end in FIG. 14) of the channel groove 4, and the electrode 5 is connected to the external connection terminal 8 through the conductive member 26. Ink enters the common ink chamber 24 from the ink supply port 27. Further, it flows from the common ink chamber 24 into each channel groove 4.
[0004]
In this inkjet head 100, when a voltage corresponding to print data is applied to the electrode 5 through the external connection terminal 8 and the conductive member 26, the channel walls 3 (see FIG. 13) on both sides of the corresponding channel groove 4 face inward. The ink in the channel groove 4 is pressurized. As a result, this ink is ejected from the nozzle hole 10.
[0005]
Ink supply from the common ink chamber 24 toward each ink chamber (space in each channel groove 4) is performed by applying a voltage to the electrode 5 opposite to that during the previous ink ejection. That is, when a voltage opposite to that applied during pressurization is applied, the channel walls 3 on both sides of the corresponding channel groove 4 are deformed so as to protrude outward, and the ink chamber becomes negative pressure. As a result, ink flows from the common ink chamber 24 into the ink chamber.
[0006]
Such a piezoelectric method has an advantage that gradation printing is easy because the pressurization amount of ink and the amount of ejected ink droplets can be controlled by controlling the deformation of the piezoelectric body by adjusting the voltage.
[0007]
However, in the conventional ink jet head as described above, if the number of ejections per unit time is increased by increasing the driving frequency to increase the printing speed, the subsequent ink ejection becomes unstable due to the residual vibration of the pressure in the ink chamber. There was a problem of becoming.
[0008]
The cause of this phenomenon can be explained as follows. When the ink in the ink chamber is pressurized, a pressure wave (vibration) is generated at the same time as the ink is ejected from the nozzle hole 10 at the front end of the ink chamber. Of these pressure waves, those that proceed toward the common ink chamber 24 are mostly reflected by the water hammer effect at the interface between the ink chamber and the common ink chamber 24, return to the ink chamber without attenuation, and the subsequent ink. This will adversely affect the discharge performance. In particular, when the drive frequency is increased, the subsequent ink discharge operation is performed before the remaining pressure wave is completely attenuated, so the discharge speed may fluctuate greatly or the discharge may become unstable. In some cases, the discharge may stop.
[0009]
On the other hand, as described in Japanese Patent Application Laid-Open No. 2000-43252 (Patent Document 1), in order to absorb a pressure wave generated by pressurization of the ink chamber, the filter is made of porous urethane or fluorine resin. There has been proposed a structure in which a vibration absorber such as a filter is provided in a communication portion between an ink chamber and a common ink chamber.
[0010]
[Patent Document 1]
JP 2000-43252 A
[0011]
[Problems to be solved by the invention]
However, in this method, a vibration absorber having a damper effect that absorbs pressure waves generated by pressurization of the ink chamber is arranged in the ink jet head, so that the structure of the ink jet head is complicated and productivity is increased. It gets worse and the cost is expensive.
[0012]
Accordingly, the present invention provides an inkjet head that can suppress residual vibration of pressure waves and can be easily manufactured in order to stabilize ink ejection even in high-speed printing, and a method for manufacturing the same.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, an ink jet head according to the present invention has a front end and a rear end, and is formed such that a plurality of channel grooves extend in the front-rear direction so as to be separated by a channel wall containing a piezoelectric material. A base member; a cover member disposed to face the surface of the base member on the side having the plurality of channel grooves; and a drive electrode disposed on at least a part of the inner surface of the channel groove. Further, between the front end and the rear end, a first region in which the cover member is bonded to the base member via a spacer member, and the cover member to the base member And a second region facing each other through a gap defined by the spacer member. By adopting this configuration, the second region acts as a so-called narrow gap portion, and can absorb and attenuate pressure waves generated as a result of ink ejection. In addition, since the size of the gap in the narrow gap portion is defined by the spacer member, high-precision machining or the like is not required, and it is easy to manufacture the gap in the gap having a desired size.
[0014]
In the above invention, preferably, the spacer member is a substantially spherical member. By adopting this configuration, the spacer member can be mixed with the adhesive and supplied. Moreover, since it is spherical, there is no need to worry about the posture of each spacer member, and a gap of a desired size can be reliably realized simply by arranging the spacer member in a desired region.
[0015]
In the above invention, the spacer member is preferably a flat plate member. By adopting this configuration, the surface exposed to the inside of the ink chamber can be smoothed, the flow of ink and the flow of bubbles in the ink become smooth, and the ink ejection performance can be improved. In addition, maintenance work for discharging bubbles from the inside of the inkjet head is facilitated.
[0016]
Preferably, in the above invention, the gap distance is 30 μm or less. By adopting this configuration, it is possible to suppress the adverse effect of the residual vibration of the pressure wave.
[0017]
In order to achieve the above object, a method of manufacturing an ink jet head according to the present invention includes a channel groove forming step of forming a plurality of channel grooves by performing groove processing on a surface of a base substrate containing a piezoelectric material, and the plurality of channels. An electrode forming step of forming an electrode on the inner wall of the groove; and the plurality of channel grooves are closed by a cover substrate, and the spacer member is sandwiched in a part of the region between the base substrate and the cover substrate. It includes a bonding step for bonding the base substrate and the cover substrate, and a dividing step for dividing the superposed substrate obtained by the bonding step. By adopting this method, it is possible to easily obtain an ink jet head having a narrow gap portion of a desired size by sandwiching the spacer member without performing highly accurate machining or the like.
[0018]
Preferably, the invention includes an adhesive supply step of supplying an adhesive containing the spacer member to a part of the surface of at least one of the base substrate and the cover substrate. By adopting this method, the spacer member is supplied in a state where it is contained in the adhesive, so that the spacer member can be efficiently arranged in a desired region. Further, the adhesive is surely spread to the place where the spacer member is present, and the spacer member can be prevented from falling off.
[0019]
In the above invention, preferably, the adhesive supplying step is included before the channel groove forming step. By adopting this method, since the adhesive is supplied to the flat surface before the channel groove is formed, it can be easily and reliably supplied to a desired region.
[0020]
In the above invention, preferably, the adhesive is in the form of a film, and the adhesive supplying step is performed by applying the adhesive. By adopting this method, the film can be cut into a desired shape in advance. Moreover, it becomes clear in which area | region an adhesive agent is arrange | positioned, and an adhesive agent can be uniformly supplied without excess and deficiency in a desired area | region.
[0021]
Preferably, in the above invention, the adhesive is in a liquid state, and the adhesive supplying step is performed by printing the adhesive. By adopting this method, an adhesive can be directly supplied to a desired site without requiring a step such as peeling, so that it can be easily adhered.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Prior to the description of the embodiments according to the present invention, an ink jet head serving as a reference of the present invention will be described with reference to FIGS. FIG. 15 shows the inkjet head 110 as viewed from the front. 16 is a cross-sectional view taken along the line XVI-XVI in FIG. In the inkjet head 110, the upper surface of the channel wall 3 of the base member 1 and the cover member 2h are bonded and fixed in the vicinity of the front end, and this portion is the active region 12, but the active region 12 and the vicinity of the rear end are close to each other. A narrow gap portion 11 is provided between the common ink chamber 24h. The narrow gap portion 11 is a portion formed by slightly digging the cover member 2h. In the narrow gap portion 11, the upper surface of the channel wall 3 of the base member 1 and the lower surface of the cover member 2h are interposed via a gap. Facing each other.
[0023]
Since the ink jet head 110 has the narrow gap portion 11, the pressure wave generated as the ink is ejected is absorbed by the viscous resistance when passing through the narrow gap portion 11, and is attenuated toward the common ink chamber 24h. And proceed. By appropriately designing the length of the narrow gap portion 11, the pressure wave is sufficiently attenuated before reaching the common ink chamber 24 h, so that the occurrence of residual vibration of the pressure wave that affects the subsequent ink ejection is not caused. Can be suppressed. As a result, high-speed and high-quality printing that is faithful to the print data is possible. In addition, an increase in material cost can be suppressed as compared with a structure in which an additional member such as a vibration absorber is arranged.
[0024]
However, in order to manufacture the inkjet head 110, it is necessary to form the narrow gap portion 11 by grinding with a dicing blade, grinding with an end mill, sandblasting, or the like. When processing such a narrow gap portion 11, it is necessary to stably process the recess depth in the narrow gap portion 11 with respect to other portions of the cover member 2 h with an accuracy of micron order. Such processing steps are complicated and difficult, and there is a problem that production efficiency and production yield are lowered.
[0025]
Therefore, the present inventors have repeatedly studied for further improvement and have come to make the present invention.
[0026]
(Embodiment 1)
(Constitution)
With reference to FIG. 1 and FIG. 2, the ink jet head in Embodiment 1 based on this invention is demonstrated. FIG. 1 shows the inkjet head 120 as viewed from the front. 2 is a cross-sectional view taken along the line II-II in FIG. In the ink jet head 120, an active region 12i, a narrow gap portion 11i, and a common ink chamber 24i are arranged in order from the front to the back between the base member 1 and the cover member 2i. The lower surface of the cover member 2i is flat across the narrow gap portion 11i and the active region 12i. However, in the active region 12i, the base member 1 and the cover member 2i are spherical silica fillers having a diameter of 30 μm as spacer members. The base member 1 and the cover member 2i are bonded so as to sandwich the adhesive 13 to which 14 is added. As a result, the gap of the narrow gap portion 11i is 30 μm. Other configurations are the same as those in the inkjet head 110.
[0027]
(Action / Effect)
Ink enters the common ink chamber 24 i from the ink supply port 27. Furthermore, it flows into the inside of each channel groove 4 from the common ink chamber 24i. The operation of the channel wall 3 when a voltage is applied is the same as that described for the inkjet head 100.
[0028]
Since the ink jet head 120 has the narrow gap portion 11 i, the pressure wave generated when ink is ejected can be absorbed and attenuated by the narrow gap portion 11 i as in the case of the ink jet head 110. Unlike the narrow gap portion 11 in the inkjet head 110, the narrow gap portion 11i in the inkjet head 120 is formed by the silica filler 14 mixed in the adhesive 13, and the size of the gap depends on the diameter of the silica filler 14 as a spacer member. Therefore, the inkjet head 120 does not need to be ground or sandblasted, and can be easily provided with a gap of a desired size.
[0029]
(Experiment)
According to the present invention, it is possible to easily realize a narrow gap portion with a desired gap. Therefore, ink jet heads having different gap sizes are prepared, and residual pressure wave vibrations are prepared. An experiment was conducted to investigate the state of. The experiment was performed with the length of the active region 12i and the length of the narrow gap portion 11i fixed, and the size of the gap varied in four ways. The evaluation was performed in four stages of ◎, ○, Δ, and × by evaluating the ink discharge performance. ◎ is the best, and x is the worst. The results are shown in Table 1.
[0030]
[Table 1]

[0031]
According to this experiment, the smaller the gap, the smaller the influence of the residual vibration of the pressure wave tends to be smaller. Conversely, when the gap is increased to 40 μm, it affects the ink ejection characteristics as in the conventional structure. I understood. This is considered to be because when the gap is larger than a certain level, the amount of pressure waves reflected at the interface between the space in the channel groove and the narrow gap portion increases. Further, an experiment was conducted separately, and it was confirmed that the length L of the narrow gap portion was as long as possible within the entire length of the inkjet head, and the effect of suppressing the residual vibration of the pressure wave was large. Therefore, it was confirmed that the adverse effect of the residual vibration of the pressure wave can be suppressed by setting the length L of the narrow gap portion as long as possible and appropriately setting the gap to 30 μm or less.
[0032]
(Embodiment 2)
(Production method)
With reference to FIGS. 3-10, the manufacturing method of the inkjet head in Embodiment 2 based on this invention is demonstrated. This inkjet head manufacturing method is a manufacturing method applicable for manufacturing the inkjet head described in the first embodiment.
[0033]
FIG. 3 shows the cover substrate 52. The cover board | substrate 52 is a board used as the material of the cover member 2i. The cover member 2 i is cut out from the cover substrate 52. FIG. 3 is a view of the cover substrate 52 as viewed from the side to be bonded to the piezoelectric substrate 51 later. Since the cover member 2 i cut out from the cover substrate 52 is bonded to the piezoelectric substrate 51 to form an ink chamber, it is preferable that the piezoelectric substrate 51 and the cover substrate 52 have the same thermal expansion coefficient. Further, it is desirable that the processing characteristics when forming the common ink chamber 24 i are not so different from the piezoelectric substrate 51.
[0034]
The cover substrate 52 is usually composed of free-cutting ceramics, a piezoelectric substrate, or the like. Further, the cover substrate 52 is formed with a recess 21 for constituting the common ink chamber 24i when bonded to the piezoelectric substrate 51. The recess 21 can be formed by patterning a resist on the cover substrate 52 and etching with aqua regia. As another method for forming the recess 21, a dry film resist is patterned on the cover substrate 52, and SiC or Al ₂ O _Three And the like can be formed by sandblasting in which particles are sprayed at a high pressure. Alternatively, it can be formed by grinding using an end mill or a dicing blade. In the first place, since the processing depth and processing position of the common ink chamber 24i do not significantly affect ink ejection, high-precision processing is not required when the recess 21 is formed.
[0035]
Next, as shown in FIG. 4, the silica filler 14 is formed in the region 32 that will be the active region 12 i (see FIG. 2) when the ink jet head is formed, and the region of the ink sealing portion 15 that does not face the ink chamber. The adhesive 13 in which is dispersed is transferred and supplied. The adhesive 13 is transferred in the form of a film having a thickness of 35 μm and die-cut into a desired shape. As shown in FIG. 5, the film-like adhesive 13 is supplied in a state of being attached to the protective film 16. A positioning hole 18 is formed in the protective film 16 simultaneously with the release of the adhesive 13. As shown in FIG. 5, positioning pins 17 are arranged on the transfer stage 22. As shown in FIGS. 4 and 5, the positioning pin 17 abuts the end of the cover substrate 52 to define the position of the cover substrate 52. At the same time, the positioning pins 17 define the position of the protective film 16 by being inserted into the positioning holes 18 as shown in FIG. As a result, the positional relationship between the cover substrate 52 and the protective film 16 is fixed.
[0036]
The adhesive 13 is pressed while being heated to 80 ° C. using the transfer tool 19. As a result, the film adhesive 13 and the cover substrate 52 are in close contact with each other. Thereafter, the protective film 16 is peeled off. If the protective film 16 is made of a thick PET film having a thickness of 100 μm or more, a tough polyimide film, or the like, dimensional accuracy such as positioning holes can be ensured.
[0037]
Here, the supply method has been described on the assumption that the adhesive is in the form of a film. However, as another method for supplying the adhesive, a method of supplying the adhesive as a liquid is also conceivable. A liquid adhesive in which spacer members are dispersed is supplied by printing using a metal mask or the like. The metal mask is positioned using positioning holes and wafer positioning pins formed in the metal mask. When using a metal mask, for example, when it is desired to form narrow gap portions with gap sizes of 10 μm, 20 μm, and 30 μm, the silica filler diameter is set to 10 μm, 20 μm, and 30 μm, respectively, and the thickness of the metal mask is set. Are printed as 20 μm, 30 μm and 40 μm, which are slightly thicker than the silica filler diameter. In this way, uniform filler dispersion can be realized, and printing supply that does not cause defects such as defective printing can be realized. However, it is desirable to use a vacuum printer that can perform printing in a vacuum if possible. Thus, when applying a liquid adhesive, since an adhesive supply apparatus and an adhesive supply process are easily realizable, a production yield improves and cost reduction can be implement | achieved.
[0038]
Next, as shown in FIG. 6, the dry film resist 20 is laminated on the upper surface of the piezoelectric substrate 51, and the channel grooves 4 are formed by the dicing blade 23 of the dicing device so as to be equidistant and equal in width. To do. The channel groove 4 has an internal space serving as an ink chamber. The piezoelectric substrate 51 is obtained by pasting together plates of piezoelectric material polarized in a certain direction in the thickness direction so that the directions of polarization are opposite to each other. The thickness of the plate used for the bonding is selected so that when the channel groove 4 is formed, the boundary (not shown) between the plates is exposed at a substantially intermediate position in the depth direction of the channel groove 4.
[0039]
As shown in FIG. 7, an electrode 5 made of Al, Cu or the like is formed by performing oblique vapor deposition of Al, Cu, etc. from two directions on the inner wall of the channel groove 4. The electrode 5 can be formed not only by oblique vapor deposition but also by sputtering or plating. When the electrode 8 is formed, a metal film is also deposited on the dry film resist 20, which is removed by peeling the dry film resist 20. In this way, the structure shown in FIG. 8 is obtained.
[0040]
Next, as shown in FIG. 9, using a dispenser 28 or the like, a conductive material 26 u made of a conductive paste is applied so as to cross the channel groove 4. The conductive material 26 u is filled in the channel groove 4 at a location where the scanning path of the dispenser 28 intersects the channel groove 4. The conductive material 26u is cured by heating. In this state, all the electrodes 5 in each ink chamber are electrically connected. Thereafter, the conductive material 26u placed on the upper surface of the piezoelectric substrate 51 is removed by polishing, whereby the ink chambers are electrically separated from each other to ensure insulation from each other. In each channel groove 4, the conductive material 26 u is cured, and the conductive member 26 having a shape separated for each channel groove 4 is disposed.
[0041]
Next, the cover substrate 52 (see FIG. 5) to which the film-like adhesive 13 is supplied and the piezoelectric substrate 51 in which the channel groove 4 is formed and the electrode 5 is formed and the conductive member 26 is filled are formed. As shown in FIG. 10, the adhesive 13 is cured and bonded by heating and pressurizing. A gap is generated where the piezoelectric substrate 51 and the cover substrate 52 face each other with the adhesive 13 interposed therebetween due to the presence of the silica filler 14 as a spacer member included in the adhesive 13, and this gap is a narrow gap portion 11i. It becomes. The superposed substrate is cut by a dicing blade along a dicing line 29 indicated by a broken line in FIG. The dicing line 29 is set so as to pass through the recessed portion 21 of the cover substrate 52 and the filling portion of the conductive member 26 of the piezoelectric substrate 51. By this cutting, the overlapping substrate is divided into individual ink jet head pieces, and the ink jet head pieces as actuators are completed. The recess 21 serves as a common ink chamber 24i.
[0042]
Further, the nozzle plate 9 is attached to the front end, or the external connection terminal 8 is attached to the rear end as necessary. As a result, the ink jet head shown in FIGS. 1 and 2 can be obtained.
[0043]
(Action / Effect)
In this embodiment, since the silica filler 14 is mixed in the adhesive 13 as a spacer member, the method of forming the narrow gap portion 11i between the base member 1 and the cover member 2i is adopted. A narrow gap can be obtained without the need for cutting or grinding. Moreover, the magnitude | size of the gap of a narrow gap part can be changed into a desired value by changing the diameter of the silica filler 14 suitably.
[0044]
Moreover, as a spacer member, it may replace with a silica filler and may use a plastic filler. When plastic filler is used, it is easy to align the filler diameter. Moreover, the adhesive which disperse | distributed the spacer member can be manufactured cheaply, and cost reduction is realizable. When a plastic filler is used, a plurality of gap sizes can be realized from one diameter. For example, just preparing an adhesive in which a plastic filler having a diameter of 30 μm is dispersed, and then controlling the degree of collapse of the filler by appropriately selecting the magnitude of the load applied when the cover substrate 52 and the piezoelectric substrate 51 are bonded. In addition, the gap size with a desired value of 30 μm or less can be arbitrarily set.
[0045]
(Embodiment 3)
(Constitution)
In the first and second embodiments, the spherical silica filler 14 is used as the spacer member, but the spacer member need not be limited to a spherical member. In Embodiment 3 based on the present invention, an inkjet head 121 will be described with reference to FIGS. 11 and 12 as an example using spacer members having different shapes. FIG. 11 shows the inkjet head 121 as viewed from the front. 12 is a cross-sectional view taken along line XII-XII in FIG. In the ink jet head 121, the base member 1 and the cover member 2i are bonded so as to sandwich the flat spacer member 19 therebetween. As the flat spacer member 19, an alumina ceramic thin plate can be used in consideration of the compatibility of the linear expansion coefficient with the base member 1 and the cover member 2i. As another material, since it is excellent in workability, a metal thin plate or a plastic thin plate can also be used.
[0046]
(Production method)
In order to manufacture the inkjet head 121, an adhesive is supplied to the front and back surfaces of the flat spacer member 19 or the piezoelectric substrate 51 and the cover substrate 52, and they are stacked and bonded together with the flat spacer member 19 interposed therebetween. That's fine. Alternatively, it is possible to prepare an adhesive in which a film-like adhesive is formed on the front and back surfaces of the flat spacer member 19 in advance, and to sandwich and sandwich this between the piezoelectric substrate 51 and the cover substrate 52 and heat and press. Both are the same as in the second embodiment in that individual substrates are obtained by dividing the substrate with a dicing blade or the like after forming the overlapping substrate.
[0047]
(Action / Effect)
Even when a flat spacer member is used as in the present embodiment, the narrow gap portion 11i can be formed, so that the same effect as in the first embodiment can be obtained.
[0048]
In the present embodiment, since the surface shape of the flat spacer member appears as it is on the surface where the adhesive is exposed toward the ink chamber, as compared with the case of the adhesive including the particulate spacer member, Much smoother. Therefore, the flow of ink and the flow of bubbles in the ink become smooth, and the ink discharge performance can be improved. In addition, there is an effect that the maintenance work for discharging the bubbles from the inside of the inkjet head can be facilitated.
[0049]
In each of the above-described embodiments, the case of a piezoelectric inkjet head has been described. However, the present invention is also applied to an ink jet head of another method (for example, thermal ink jet method) having a different ink ejection principle as long as the basic structure (ink pressurizing chamber, common ink chamber) of the ink flow path is the same. can do.
[0050]
In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.
[0051]
【The invention's effect】
According to the present invention, the region where the cover member is opposed to the base member via the gap defined by the spacer member acts as a so-called narrow gap, and absorbs the pressure wave generated along with ink ejection, Can be attenuated. In addition, since the size of the gap in the narrow gap portion is defined by the spacer member, high-precision machining or the like is unnecessary, and it is easy to manufacture the gap in the gap having a desired size.
[Brief description of the drawings]
FIG. 1 is a front view of an ink jet head according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the ink jet head according to the first embodiment of the present invention.
FIG. 3 is a plan view of a cover substrate used in the ink jet head manufacturing method according to the second embodiment of the present invention.
FIG. 4 is a plan view showing a state in which an adhesive is applied to a cover substrate used in the method for manufacturing an ink jet head according to Embodiment 2 of the present invention.
FIG. 5 is an explanatory diagram of a process of pressing a protective film against a cover substrate, which is performed by the method of manufacturing an ink jet head according to the second embodiment of the present invention.
FIG. 6 is an explanatory diagram of a first step of a method of manufacturing an ink jet head according to the second embodiment of the present invention.
FIG. 7 is an explanatory diagram of a second step of the ink jet head manufacturing method according to the second embodiment of the present invention.
FIG. 8 is an explanatory diagram of a third step of the inkjet head manufacturing method according to the second embodiment of the present invention.
FIG. 9 is an explanatory diagram of a fourth step of the method of manufacturing the ink jet head according to the second embodiment of the present invention.
10 is an explanatory diagram of a fifth step of the method of manufacturing the ink jet head according to the second embodiment of the present invention. FIG.
FIG. 11 is a front view of an ink jet head according to a third embodiment of the present invention.
FIG. 12 is a cross-sectional view of an ink jet head according to a third embodiment of the present invention.
FIG. 13 is a front view of an ink jet head based on a conventional technique.
FIG. 14 is a cross-sectional view of an ink jet head based on a conventional technique.
FIG. 15 is a front view of an ink jet head serving as a reference of the present invention.
FIG. 16 is a cross-sectional view of an ink jet head serving as a reference of the present invention.
[Explanation of symbols]
1 Base member, 2, 2h, 2i Cover member, 3 Channel wall, 4 Channel groove, 5 Electrode, 8 External connection terminal, 9 Nozzle plate, 10 Nozzle hole, 11, 11i Narrow gap part, 12, 12i Active region, 13 Adhesive, 14 Silica filler, 15 Ink sealing part, 16 Protective film, 17 Positioning pin, 18 Positioning hole, 19 Flat spacer member, 20 Dry film resist, 21 Recess, 23 Dicing blade, 24, 24h Common ink chamber , 26 conductive member, 26u conductive material (before solidification), 27 ink supply port, 28 dispenser, 29 dicing line, 32 (to be an active region), 51 piezoelectric substrate, 52 cover substrate.

Claims (7)

A base member having a front end and a rear end, wherein the plurality of channel grooves extend in the front-rear direction so as to be separated from the channel wall containing the piezoelectric material;
A cover member arranged to face the surface of the base member on the side having the plurality of channel grooves;
A drive electrode disposed on at least a part of the inner surface of the channel groove,
Between the front end and the rear end, a first region in which the cover member is bonded to the base member via a spacer member, and the cover member to the base member through a gap defined possess a second region opposed by,
A surface of the cover member facing the base member is provided with a common ink chamber that communicates in common with the plurality of channel grooves,
The spacer member is an ink jet head having a substantially spherical shape . The inkjet head according to claim 1, wherein a distance between the gaps is 30 μm or less. An inkjet head manufacturing method for obtaining the inkjet head according to claim 1, comprising:
A channel groove forming step of forming a plurality of channel grooves by performing groove processing on the surface of the base substrate containing the piezoelectric material;
An electrode forming step of forming electrodes on the inner walls of the plurality of channel grooves;
An adhering step of adhering the base substrate and the cover substrate so as to close the plurality of channel grooves with a cover substrate and sandwiching a spacer member between the base substrate and the cover substrate in a partial region; ,
A method of manufacturing an inkjet head, the method including a dividing step of dividing the superposed substrate obtained by the bonding step. The method of manufacturing an ink jet head according to claim 3 , further comprising an adhesive supplying step of supplying an adhesive including the spacer member to a part of a surface of at least one of the base substrate and the cover substrate. The method of manufacturing an ink jet head according to claim 4 , wherein the adhesive supplying step is included before the channel groove forming step. Wherein said adhesive is a film-like, the adhesive supplying step is carried out by pasting the adhesive, ink jet head manufacturing method according to claim 4 or 5. The adhesive is a liquid, the adhesive supplying step is carried out by printing the adhesive, ink jet head manufacturing method according to claim 4 or 5.

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