JP2004066606A - Liquid drop ejecting head, its manufacturing process and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid drop ejecting head and its manufacturing process in which high reliability is attained by suppressing variation in the characteristics, and to provide an inkjet recorder capable of recording with high image quality using the liquid drop ejecting head. <P>SOLUTION: A gap 12 is formed between a diaphragm 10 and an electrode 14 by removing a sacrifice layer formed on the electrode 14 after formation of the electrode 14 and the diaphragm 10. A multilayer diaphragm having two or more layers is preferably employed. Furthermore, a cavity is provided under the electrode to communicate with the gap and an insulating film is provided on the both sides of the electrode. <P>COPYRIGHT: (C)2004,JPO

Description

【００３９】
なお、（１）式において、Ｆ：電極間に働く力、ε：誘電率、Ｓ：電極の対向する面の面積、ｄ：電極間距離、Ｖ：印加電圧である。
【００４０】
次に、このインクジェットヘッドの製造方法の第１実施形態について図３ないし図５を参照して説明する。なお、図３及び図４は同製造方法の説明に供する断面説明図、図５は同じく平面説明図である。
【００４１】
本実施形態においては、後に液室（吐出室）６を形成する第１基板１に振動板材料及び電極材料を成膜していくことで静電型アクチュエータを作製する。
先ず、図３（ａ）に示すように、第１基板１を構成する主基板１１となる面方位（１１０）のシリコン基板３１の表面に振動板１０となる窒化膜１０ａを０．２μｍ厚み及び共通電極となるポリシリコン膜１０ｂを０．１μｍ厚み、更に本実施形態では酸化膜１０ｃを０．８μｍ厚みにそれぞれ成膜する。
【００４２】
なお、膜厚については上記の値に限らず、ギャップ間隔及び振動板短辺長による振動板剛性を考慮して最適な値に設定すればよい。また、共通電極は絶縁膜（ここでは、窒化膜１０ａと酸化膜１０ｃ）に挟まれた構成となっているので導電性の膜であればほとんど膜が使用可能である。
【００４３】
そして、酸化膜１０ｃ上にポリシリコン３２を０．５μｍ厚みに成膜する。ポリシリコン３２は犠牲層として用いるための材料で、この膜厚がギャップ間隔となるため、前記振動板材料の膜厚と同様に上記の値に限らず最適な膜厚に設定すればよい。
【００４４】
さらに、ポリシリコン３２上に絶縁膜１３となる酸化膜３３及び個別電極１４を成膜する。個別電極１４の材料としては、ポリシリコンやＡｌ、ＴｉＮ、Ｔｉ、Ｗ、ＩＴＯなどを用いることができる。
【００４５】
次いで、個別電極１４をリソ／エッチ法により電極形状にパターニングし、また酸化膜３３及びポリシリコン３２も所要の形状にパターニングする。
【００４６】
そして、同図（ｂ）に示すように、個別電極１４表面及び露出している酸化膜１０ｃ表面などを含めて酸化膜３３上にＣＶＤ法により絶縁膜１５となる酸化膜３５を５μｍ厚みに成膜し、ＣＭＰ法により約１μｍの研磨を行なって表面を平坦化する。ここで、ＣＭＰ法による平坦化は必ずしも必要なわけではない。また酸化膜３５の膜厚は振動板１０の膜厚よりも十分に厚い膜厚とし、酸化膜３３及び個別電極１４及び並びに酸化膜３５の総膜厚の膜剛性が少なくとも積層膜からなる振動板１０の剛性の１０倍以上となる膜厚とすることが好ましい。
【００４７】
次に、同図（ｃ）及び図５に示すように、犠牲層であるポリシリコン３２を除去するための除去孔（連通孔）１８を形成するため、リソ／エッチ法により酸化膜３３、個別電極１４、酸化膜３５をパターニングする。なお、個別電極１４には図５に示すように電極パッド部１４ａも形成する。その後、酸化を行なって除去孔１８の側面に露出した個別電極１４表面に酸化膜を形成し、ＳＦ_６を用いた等方性のドライエッチングによりポリシリコン３２を除去する。
【００４８】
ここで、犠牲層であるポリシリコン３２の周りを酸化膜３５で囲んだ構造としているため、酸化膜３５に対して選択性の高い犠牲層エッチング条件で犠牲層を除去でき、ギャップを精度良く形成することができる。犠牲層であるポリシリコン３２の除去方法としては、ＴＭＡＨを用いたウェットエッチングでも良いし、ＸＦ_２ガスを用いた常圧ドライエッチングでも良い。
【００４９】
また、ここでは、図５に示すように、格子状に犠牲層除去孔１８を配置しているが、犠牲層除去孔１８は犠牲層を効率よく除去するために電極面に均一に配置されていればよく、配置パターンはこの限りではない。ただし、除去孔１８を数多く配置することは個別電極１４の面積を低下させることにつながり電極間の静電力を弱めることになるため、犠牲層除去プロセスとの整合を図り、数、形状、寸法等最適な配置を選択する必要がある。
【００５０】
その後、図４（ａ）に示すように、ギャップ１２に対応する部分に凹部１６及び連通溝１７を形成した保護基板（第２基板）２を接着剤３６によりシリコン基板３１に貼り合わせ、基板１表面に窒化膜３７を成膜し、リソ／エッチ法により液室パターンに窒化膜３７に形成し、同図（ｂ）に示すように窒化膜３７のパターンをマスクとしてＫＯＨによるウェットエッチングでシリコン基板３１に吐出室（液室）６を形成する。
【００５１】
なお、液室６の形成はＳＦ_６ガスを用いたＩＣＰエッチングによるドライエッチングで形成することも可能であるが、この場合、マスクは窒化膜３７に代えて酸化膜とし、窒化膜１０ａ成膜前に酸化膜１０ｃを成膜して３層構造の積層振動板にしておくことで、酸化膜をマスクとして液室６の形成が可能となる。また、この場合、シリコン基板３１を面方位（１００）の基板とすることができ、材料コストを下げることができる。
【００５２】
このように、ポリシリコンを犠牲層として使用することにより、半導体製造で使用されているエッチング材料を用いて犠牲層除去が可能になり、また上下に対エッチング性の高いシリコン酸化膜を成膜することでバラツキの少ない製造プロセスとすることができて、低コストでの大量生産が可能となる。
【００５３】
また、犠牲層としてポリシリコンに代えて、シリコン酸化膜を用いることもできる。この場合はシリコン酸化膜の保護膜としてポリシリコンを用いることが好ましい。この場合、犠牲層酸化膜をウエットエッチ法、ＨＦベーパー法、ケミカルドライエッチング法などにより除去後、保護膜としてポリシリコン表面を酸化することで絶縁層を形成する。
【００５４】
このように、シリコン酸化膜を犠牲層として使用することにより、半導体製造で使用されているエッチング材料を用いて犠牲層除去が可能であり、また上下に対エッチング性の高いポリシリコン膜を成膜することでバラツキの少ない製造プロセスとすることができ、低コストでの大量生産が可能となる。
【００５５】
また、犠牲層酸としてレジストを用いてＯ_２プラズマや剥離液で除去する方法、犠牲層に高分子材料を用いて有機系剥離液で除去する方法、犠牲層にアルミを用いてＫＯＨなどの薬液で除去する方法、犠牲層にＴｉＮ用いてＮＨ_３ＯＨとＨ_２Ｏ_２混合液などの薬液で除去する方法等色々な組み合わせで同様のプロセスを組み立てることができる。
【００５６】
なお、図では省略したが、最後にノズル板３を基板３１表面に張り合わせることで静電型液滴吐出ヘッドが完成する。
【００５７】
上記製造工程により作製された液滴吐出ヘッドは、犠牲層膜厚によりギャップ間隔を規定するため、精度良く、且つバラツキの少ないギャップ形成が可能である。また、直接接合や陽極接合などが必要なく、大半を半導体プロセスで作成できるため、歩留まり良く安定した液滴吐出ヘッドを製造することができる。
【００５８】
次に、本発明に係る液滴吐出ヘッドであるインクジェットヘッドの第２実施形態についてその製造方法の第２実施形態とともに図６ないし図８を参照して説明する。なお、図６及び図７は同製造方法の説明に供する断面説明図、図８は同じく平面説明図である。
【００５９】
本実施形態では、振動板面から犠牲層を除去し、感光性ポリイミドにより犠牲層除去孔の封止と液室形成を行なっている。
先ず、図６（ａ）に示すように、面方位（１００）のシリコン基板４１に熱酸化膜４５を約１．０μｍの厚みに形成してから個別電極となるポリシリコン４４を０．５μｍの厚みに成膜する。このポリシリコン４４に低抵抗化のために燐をドープ後、リソエッチ法により電極分離溝４４ｂを形成した後、高温酸化膜（ＨＴＯ膜）４３を０．２５μｍ厚みに成膜する。なお、個別電極となるポリシリコン４４には図８に示すように電極パッド部４４ａも形成する。
【００６０】
次いで、図７（ｂ）に示すように、ＨＴＯ膜４３上に犠牲層となるポリシリコン４２を０．５μｍ厚みに成膜した後、リソエッチ法により分離溝４２ａを形成し、さらに高温酸化膜（ＨＴＯ膜）５０ｃを０．１μｍ厚みに成膜する。
【００６１】
さらに、同図（ｃ）に示すように、共通電極となるポリシリコン５０ｂを０．５μｍ厚みに、次いで振動板保護膜となる酸化膜５０ａを０．５μｍ厚みに成膜する。その後、リソエッチ法により犠牲層除去孔５１を後に液室間隔壁となる領域に形成するために、犠牲層除去孔５１よりオーバーサイズしたパターンをリソエッチ法により形成し、酸化膜５０ａ、ポリシリコン５０ｂの順にエッチングを行なう。その後、酸化を行なって除去孔５１の側面に露出したポリシリコン５０ｂ表面に酸化膜５０ｂ１を形成する。
【００６２】
その後、図７（ａ）及び図８に示すように、リソエッチ法により除去孔５１のパターニングを行ない酸化膜５０ｃをエッチング除去し、ＳＦ_６を用いた等方性のドライエッチングにより犠牲層４２を除去してギャップ５２を形成する。なお、前記第１実施形態と同様にＴＭＡＨを用いたウェットエッチングでも良いし、ＸＦ_２ガスを用いた常圧ドライエッチングでも良い。
【００６３】
次いで、図７（ｂ）に示すように、液室間隔壁となる部分に感光性ポリイミド５３をスピンコートにより１００μｍ厚みに成膜し、犠牲層除去孔５１の封止及び露光現像による液室５６のパターンを形成を行う。その後、３５０℃−５時間ベークを行ないポリイミド５３を硬化させ液室間隔壁とする。
【００６４】
なお、図では省略したが、最後にノズル板３をポリイミド５３表面に貼り合わせることで静電型液滴吐出ヘッドが完成する。
【００６５】
この場合、振動板５０は、酸化膜５０ａ、ポリシリコン５０ｂ及びＨＴＯ膜５０ｃで構成され、この振動板５０はギャップ５２間の隔壁領域に対応する液室間隔壁の領域において除去孔５１により部分的に除去された構造となる。
【００６６】
すなわち、隔壁領域において犠牲層除去孔を形成するために振動板が部分的に除去されているので、吐出室の一方の壁を構成する振動板に影響せずに犠牲層を除去でき、信頼性の高い液滴吐出ヘッドとすることができ、また、下部電極を保護する保護基板も必要が無いためより低コスト化を図れる。
【００６７】
また、上記製造工程により作製した液滴吐出ヘッドは、犠牲層膜厚によりギャップ間隔を規定するため、精度良く、且つバラツキの少ないギャップ形成が可能である。また、直接接合や陽極接合などが必要なく、２枚の基板で液滴吐出ヘッドを構成することができ、一層の低コストなヘッドを作成できる。また、大半を半導体プロセスで作成できるため、歩留まり良く安定した液滴吐出ヘッドが得られる。
【００６８】
次に、本発明に係る液滴吐出ヘッドのインクカートリッジ一体型ヘッドについて図９を参照して説明する。
このインクカートリッジ一体型ヘッド１００は、ノズル孔１０１等を有する上記各実施形態のいずれかのインクジェットヘッド１０２と、このインクジェットヘッド１０１に対してインクを供給するインクタンク１０３とを一体化したものである。
【００６９】
このように本発明に係る液滴吐出ヘッドにインクを供給するインクタンクを一体化することにより、滴吐出効率が高く、安定した滴吐出特性が得られる液滴吐出ヘッドを一体化したインクカートリッジ（インクタンク一体型ヘッド）が得られる。
【００７０】
次に、本発明に係るインクジェットヘッド（ヘッド一体型のインクカートリッジを含む。）を搭載したインクジェット記録装置の機構の一例について図１０及び図１１を参照して説明する。なお、図１１は同記録装置の斜視説明図、図１２は同記録装置の機構部の側面説明図である。
【００７１】
このインクジェット記録装置は、記録装置本体１１１の内部に主走査方向に移動可能なキャリッジ、キャリッジに搭載した本発明に係るインクジェットヘッドからなる記録ヘッド、記録ヘッドへインクを供給するインクカートリッジ等で構成される印字機構部１１２等を収納し、装置本体１１１の下方部には前方側から多数枚の用紙１１３を積載可能な給紙カセット（或いは給紙トレイでもよい。）１１４を抜き差し自在に装着することができ、また、用紙１１３を手差しで給紙するための手差しトレイ１１５を開倒することができ、給紙カセット１１４或いは手差しトレイ１１５から給送される用紙１１３を取り込み、印字機構部１１２によって所要の画像を記録した後、後面側に装着された排紙トレイ１１６に排紙する。
【００７２】
印字機構部１１２は、図示しない左右の側板に横架したガイド部材である主ガイドロッド１２１と従ガイドロッド１２２とでキャリッジ１２３を主走査方向（図１５で紙面垂直方向）に摺動自在に保持し、このキャリッジ１２３にはイエロー（Ｙ）、シアン（Ｃ）、マゼンタ（Ｍ）、ブラック（Ｂｋ）の各色のインク滴を吐出する本発明に係る液滴吐出ヘッドであるインクジェットヘッドからなるヘッド１２４を複数のインク吐出口を主走査方向と交叉する方向に配列し、インク滴吐出方向を下方に向けて装着している。またキャリッジ１２３にはヘッド１２４に各色のインクを供給するための各インクカートリッジ１２５を交換可能に装着している。
【００７３】
インクカートリッジ１２５は上方に大気と連通する大気口、下方にはインクジェットヘッドへインクを供給する供給口を、内部にはインクが充填された多孔質体を有しており、多孔質体の毛管力によりインクジェットヘッドへ供給されるインクをわずかな負圧に維持している。
【００７４】
また、記録ヘッドとしてここでは各色のヘッド１２４を用いているが、各色のインク滴を吐出するノズルを有する１個のヘッドでもよい。
【００７５】
ここで、キャリッジ１２３は後方側（用紙搬送方向下流側）を主ガイドロッド１２１に摺動自在に嵌装し、前方側（用紙搬送方向上流側）を従ガイドロッド１２２に摺動自在に載置している。そして、このキャリッジ１２３を主走査方向に移動走査するため、主走査モータ１２７で回転駆動される駆動プーリ１２８と従動プーリ１２９との間にタイミングベルト１３０を張装し、このタイミングベルト１３０をキャリッジ１２３に固定しており、主走査モーター１２７の正逆回転によりキャリッジ１２３が往復駆動される。
【００７６】
一方、給紙カセット１１４にセットした用紙１１３をヘッド１２４の下方側に搬送するために、給紙カセット１１４から用紙１１３を分離給装する給紙ローラ１３１及びフリクションパッド１３２と、用紙１１３を案内するガイド部材１３３と、給紙された用紙１１３を反転させて搬送する搬送ローラ１３４と、この搬送ローラ１３４の周面に押し付けられる搬送コロ１３５及び搬送ローラ１３４からの用紙１１３の送り出し角度を規定する先端コロ１３６とを設けている。搬送ローラ１３４は副走査モータ１３７によってギヤ列を介して回転駆動される。
【００７７】
そして、キャリッジ１２３の主走査方向の移動範囲に対応して搬送ローラ１３４から送り出された用紙１１３を記録ヘッド１２４の下方側で案内する用紙ガイド部材である印写受け部材１３９を設けている。この印写受け部材１３９の用紙搬送方向下流側には、用紙１１３を排紙方向へ送り出すために回転駆動される搬送コロ１４１、拍車１４２を設け、さらに用紙１１３を排紙トレイ１１６に送り出す排紙ローラ１４３及び拍車１４４と、排紙経路を形成するガイド部材１４５，１４６とを配設している。
【００７８】
記録時には、キャリッジ１２３を移動させながら画像信号に応じて記録ヘッド１２４を駆動することにより、停止している用紙１１３にインクを吐出して１行分を記録し、用紙１１３を所定量搬送後次の行の記録を行う。記録終了信号または、用紙１１３の後端が記録領域に到達した信号を受けることにより、記録動作を終了させ用紙１１３を排紙する。この場合、ヘッド１２４を構成する本発明に係るインクジェットヘッドはインク滴噴射の制御性が向上し、特性変動が抑制されているので、安定して高い画像品質の画像を記録することができる。
【００７９】
また、キャリッジ１２３の移動方向右端側の記録領域を外れた位置には、ヘッド１２４の吐出不良を回復するための回復装置１４７を配置している。回復装置１４７はキャップ手段と吸引手段とクリーニング手段を有している。キャリッジ１２３は印字待機中にはこの回復装置１４７側に移動されてキャッピング手段でヘッド１２４をキャッピングされ、吐出口部を湿潤状態に保つことによりインク乾燥による吐出不良を防止する。また、記録途中などに記録と関係しないインクを吐出することにより、全ての吐出口のインク粘度を一定にし、安定した吐出性能を維持する。
【００８０】
吐出不良が発生した場合等には、キャッピング手段でヘッド１２４の吐出口（ノズル）を密封し、チューブを通して吸引手段で吐出口からインクとともに気泡等を吸い出し、吐出口面に付着したインクやゴミ等はクリーニング手段により除去され吐出不良が回復される。また、吸引されたインクは、本体下部に設置された廃インク溜（不図示）に排出され、廃インク溜内部のインク吸収体に吸収保持される。
【００８１】
このように、このインクジェット記録装置においては本発明に係る液滴吐出ヘッドであるインクジェットヘッドを搭載しているので、低コストで高い画像品質の画像を記録できる記録装置が得られる。
【００８２】
次に、本発明に係る液滴吐出ヘッドのアクチュエータ部分を適用したマイクロデバイスとしてのマイクロポンプについて図１２を参照して説明する。なお、同図は同マイクロポンプの要部断面説明図である。
このマイクロポンプは、流路基板２０１とアクチュエータ基板２０２とを有している。流路基板２０１には流体が流れる流路２０３を形成している。アクチュエータ基板２０２は、支持基板２１０上に、流路２０１の壁面を形成する変形可能な可動板２０４（ヘッドの振動板に相当する。）と、この可動板２０４の可動部分２０４ａ（固定されていない部分）にギャップ２０５を介して対向する電極２０６とを有する。
【００８３】
可動板２０４は詳細な図示を省略しているが、前記インクジェットヘッドの実施形態で説明したと同様に、共通電極材料の膜両面を絶縁膜で挟んだ積層膜で形成している。また、電極２０６の両面にもそれぞれ絶縁膜２０７、２０８を形成している。
【００８４】
このマイクロポンプの動作原理を説明すると、前述したインクジェットヘッドの場合と同様に、電極２０６に対して選択的にパルス電位を与えることによって可動板２０４との間で静電吸引力が生じるので、可動板２０４の可動部分２０４ａが電極２０６側に変形する。ここで、可動板２０４の可動部分２０４ａを図中右側から順次駆動することによって流路２０３内の流体は、矢印方向へ流れが生じ、流体の輸送が可能となる。
【００８５】
この場合、本発明に係る液滴吐出ヘッドのアクチュエータを備えることで、小型で低消費電力のマイクロポンプを得られる。なお、ここでは可動板の可動部分が複数ある例を示したが、可動部分は１つでも良い。また、輸送効率を上げるために、可動部分間に１又は複数の弁、例えば逆止弁などを設けることもできる。
【００８６】
次に、本発明に係る液滴吐出ヘッドのアクチュエータ部分を適用した光学デバイスの一例について図１３を参照して説明する。なお、同図は同デバイスの概略構成図である。
この光学デバイスは、変形可能なミラー３０１を含むアクチュエータ基板３０２を有している。ミラー３０１の表面は反射率を増加させるため誘電体多層膜や金属膜を形成すると良い。
【００８７】
アクチュエータ基板３０２は、支持基板３１０上に、変形可能なミラー３０１（ヘッドの振動板に相当する。）と、このミラー３０１の可動部分３０１ａ（固定されていない部分）にギャップ３０５を介して対向する電極３０６とを有する。なお、電極３０６の両面にはそれぞれ絶縁膜３０７、３０８を形成している。
【００８８】
この光学デバイスの原理を説明すると、前述したインクジェットヘッドの場合と同様に、電極３０６に対して選択的にパルス電位を与えることによって、電極３０６と対向するミラー３０１の可動部分３０１ａ間で静電吸引力が生じるので、ミラー３０１の可動部分３０１ａが凹状に変形して凹面ミラーとなる。したがって、光源３１０からの光がレンズ３１１を介してミラー３０１に照射した場合、ミラー３０１を駆動しないときには、光は入射角と同じ角度で反射するが、ミラー３０１の可動部分３０１ａを駆動した場合はその可動部分３０１ａが凹面ミラーとなるので反射光は発散光となる。これにより光変調デバイスが実現できる。
【００８９】
そして、本発明の液滴吐出ヘッドのアクチュエータを備えることで小型で低消費電力の光学デバイスを得ることができる。
【００９０】
そこで、この光学デバイスを応用した例を図１４をも参照して説明する。この例は、上述した光学デバイスを２次元に配列し、各ミラー３０１の可動部分３０１ａを独立して駆動するようにしたものである。なお、ここでは、４×４の配列を示しているが、これ以上配列することも可能である。
【００９１】
したがって、前述した図１３と同様に、光源３１０からの光はレンズ３１１を介してミラー３０１に照射され、ミラー３０１を駆動していないところに入射した光は、投影用レンズ３１２へ入射する。一方、電極３０６に電圧を印加してミラー３０１の可動部分３０１ａを変形させているところは凹面ミラーとなるので光は発散し投影用レンズ３１２にほとんど入射しない。この投影用レンズ３１２に入射した光はスクリーン（図示しない）などに投影され、スクリーンに画像を表示することができる。
【００９２】
なお、上記実施形態においては、液滴吐出ヘッドとしてインクジェットヘッドに適用した例で説明したが、インクジェットヘッド以外の液滴吐出ヘッドとして、例えば、液体レジストを液滴として吐出する液滴吐出ヘッド、ＤＮＡの試料を液滴として吐出する液滴吐出ヘッドなどの他の液滴吐出ヘッドにも適用できる。また、液滴吐出ヘッドを構成するアクチュエータは、マイクロポンプ、光学デバイス（光変調デバイス）以外にも、マイクロスイッチ（マイクロリレー）、マルチ光学レンズのアクチュエータ（光スイッチ）、マイクロ流量計、圧力センサなどにも適用することができる。
【００９３】
【発明の効果】
以上説明したように、本発明に係る液滴吐出ヘッドによれば、振動板と電極との間のギャップは電極上に形成された犠牲層を電極及び振動板形成後に除去することにより形成されたので、ギャップのバラツキが低減して特性のバラツキが少なく高い信頼性が得られる。
【００９４】
本発明に係る液滴吐出ヘッドの製造方法は、本発明に係る液滴吐出ヘッドを製造する方法であって、犠牲層にポリシリコン又はシリコン酸化膜を用いる構成としたので、ヘッドの低コスト化を図れる。
【００９５】
本発明に係るインクジェット記録装置によれば、インク滴を吐出するインクジェットヘッドが本発明に係る液滴吐出ヘッドである構成としたので、高画質記録を行うことができる。
【図面の簡単な説明】
【図１】本発明の液滴吐出ヘッドの第１実施形態に係るインクジェットヘッドの分解斜視説明図
【図２】同ヘッドの振動板短手方向に沿う断面説明図
【図３】本発明の液滴吐出ヘッドであるインクジェットヘッドの製造方法の第１実施形態の説明に供する断面説明図
【図４】図３に続く工程を説明する断面説明図
【図５】同工程の説明に供する平面説明図
【図６】本発明の液滴吐出ヘッドであるインクジェットヘッド及びその製造方法の第２実施形態の説明に供する断面説明図
【図７】図６に続く工程を説明する断面説明図
【図８】同工程の説明に供する平面説明図
【図９】本発明に係る液滴吐出ヘッドを含むインクカートリッジ一体型ヘッドの説明に供する斜視説明図
【図１０】本発明に係るインクジェット記録装置の一例を説明する斜視説明図
【図１１】同記録装置の機構部の説明図
【図１２】本発明に係る液滴吐出ヘッドのアクチュエータ部分を適用したマイクロポンプの一例を説明する説明図
【図１３】本発明に係る液滴吐出ヘッドのアクチュエータ部分を適用した光学デバイスの一例を説明する説明図
【図１４】同光学デバイスを用いた光変調デバイスの一例を説明する斜視説明図
【符号の説明】
１…第１基板、２…第２基板、３…ノズル板、４…ノズル孔、６…吐出室、７…流体抵抗部、８…共通液室、１０…振動板、１２…ギャップ、１４…電極、１００…インクカートリッジ一体型ヘッド、１２４…記録ヘッド、２０１…流路基板、２０３…流路、２０４ａ…可動部分、２０６…電極、３０１…ミラー、３０４ａ…可動部分、３０６…電極。[0001]
[Industrial applications]
The present invention relates to a droplet discharge head, a method for manufacturing the same, and an ink jet recording apparatus.
[0002]
[Prior art]
An inkjet head, which is a droplet ejection head used in an image recording apparatus such as a printer, a facsimile, and a copying apparatus or an inkjet recording apparatus used as an image forming apparatus, includes a single or a plurality of nozzle holes for discharging ink droplets, and the nozzle holes. A discharge chamber (also referred to as a pressure chamber, an ink chamber, a liquid chamber, a pressurized liquid chamber, a pressure chamber, an ink flow path, etc.) communicating with the pressure chamber, and a pressure generating means for generating a pressure for pressurizing the ink in the discharge chamber. Ink is ejected from the nozzle holes by pressurizing the ink in the ejection chamber with the pressure generated by the pressure generating means.
[0003]
The droplet discharge head includes, for example, a droplet discharge head that discharges a liquid resist as droplets, a droplet discharge head that discharges a DNA sample as droplets, and the like. . The microactuator constituting the actuator portion of the droplet discharge head includes, for example, a micropump, an optical device such as a micro light modulation device, a micro switch (micro relay), a multi-optical lens actuator (optical switch), a micro flow meter, It can be applied to a pressure sensor and the like.
[0004]
By the way, as a droplet discharge head, a piezo type that discharges ink droplets by deforming and displacing a diaphragm forming a wall surface of a discharge chamber using an electromechanical transducer such as a piezoelectric element as a pressure generating means. A thermal type in which bubbles are generated by ink film boiling using an electrothermal conversion element such as a heating resistor disposed in a discharge chamber to discharge ink droplets, and a vibrating plate forming a wall surface of the discharge chamber is statically moved. There is an electrostatic type in which ink droplets are ejected by being deformed by electric power.
[0005]
In recent years, a bubble type and an electrostatic type, which are lead-free due to environmental problems, have attracted attention. In addition to lead-free, a plurality of electrostatic types have been proposed which have little effect on the environment from the viewpoint of low power consumption.
[0006]
As this electrostatic ink jet head, for example, as described in JP-A-6-71882, a pair of electrodes is provided via an air gap, and one electrode functions as a diaphragm, An ink chamber filled with ink is formed on the opposite side of the diaphragm from the opposite electrode, and by applying a voltage between the electrodes (between the diaphragm and the electrode), an electrostatic attractive force acts between the electrodes and the electrode (vibration plate) is formed. ) Is deformed and when the voltage is removed, the diaphragm returns to its original state by the elastic force, and there is a type in which an ink droplet is ejected using the force.
[0007]
Japanese Patent Application Laid-Open No. 2001-18383 describes that a small gap between a diaphragm and an electrode is formed by sacrificial layer etching, and a liquid chamber substrate is bonded thereon to form a head. Japanese Patent Application Laid-Open No. H11-314363 discloses that a diaphragm having a single-stick or double-stick structure in which ink can flow into a gap is formed, and low-voltage driving is possible by filling the gap with high-permittivity ink. Is described.
[0008]
[Problems to be solved by the invention]
By the way, in an electrostatic ink jet head having a diaphragm and electrodes facing each other, the air gap between the electrodes must be made very small in order to reduce the voltage.
[0009]
However, in the head described in Japanese Patent Application Laid-Open No. 6-71882, an air gap is created by forming a concave portion by etching and bonding to a diaphragm substrate by anodic bonding. There is a problem that it is very difficult to form a small amount and the yield does not increase.
[0010]
Therefore, in the head described in Japanese Patent Application Laid-Open No. 2001-18383, a gap formation method using sacrifice layer etching is used as a method for forming a gap with high accuracy, but holes for sacrifice layer etching are formed on the diaphragm surface. Therefore, the reliability of the diaphragm decreases. In addition, since the method of closing the etching hole with the insulating film after the sacrifice layer etching is used, it is necessary to form a thick insulating film for sealing the hole, the rigidity of the diaphragm increases, the driving voltage increases, In addition, there is a problem that the diaphragm rigidity is a factor of variation.
[0011]
In the head described in JP-A-11-314363, a gap is formed by etching a sacrificial layer. ing. In this case, there is no need to form a hole for etching the sacrificial layer, and the ink can penetrate into the gap. Therefore, by using a high dielectric constant ink, the effective gap can be reduced and low voltage driving is possible. However, since a voltage is applied to the ink in the gap, there is a problem that the problem of aggregation of the ink components easily occurs, and high-speed driving cannot be performed due to the conductance of the ink in the gap.
[0012]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and a droplet discharge head that has small variations in characteristics and high reliability, a method of manufacturing the droplet discharge head, and high image quality by including the droplet discharge head An object of the present invention is to provide an ink jet recording apparatus capable of recording.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, in the droplet discharge head according to the present invention, the gap between the diaphragm and the electrode is formed by removing the sacrificial layer formed on the electrode after the formation of the electrode and the diaphragm. It is a configuration that is a thing.
[0014]
Here, it is preferable that the diaphragm is formed of a laminated film of two or more layers. Preferably, the electrodes are partially removed. Further, it is preferable that a cavity is provided below the electrode, and the gap and the cavity communicate with each other. Further, it is preferable that an insulating film is provided on both surfaces of the electrode, and the total thickness of the electrode and the insulating film is larger than the thickness of the laminated diaphragm.
[0015]
Further, it is preferable that the diaphragm is partially removed in a partition region between a plurality of gaps that are continuously arranged.
[0016]
A method for manufacturing a droplet discharge head according to the present invention is a method for manufacturing a droplet discharge head according to the present invention, and has a configuration in which polysilicon is used for a sacrificial layer. Here, it is preferable to form silicon oxide films above and below the sacrificial layer film made of polysilicon.
[0017]
Further, a method for manufacturing a droplet discharge head according to the present invention is a method for manufacturing a droplet discharge head according to the present invention, wherein a silicon oxide film is used for a sacrificial layer. Here, it is preferable to form polysilicon above and below the sacrificial layer film made of a silicon oxide film.
[0018]
The droplet discharge head according to the present invention may have a configuration in which an ink tank for supplying ink is integrated.
[0019]
The droplet discharge head according to the present invention is configured such that the inkjet head that discharges ink droplets is the droplet discharge head according to the present invention.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of an ink jet head according to a first embodiment of the droplet discharge head of the present invention, and is a partial cross-sectional view. FIG. 2 is an explanatory cross-sectional view of the same head taken along the transverse direction of the diaphragm.
[0021]
This ink jet head is of a side shooter type in which ink droplets are ejected from nozzle holes provided in a surface portion of a substrate, and three first, second, and third substrates 1, 2, and 3 are overlapped and joined. The first substrate 1 and the third substrate 3 are joined to form a discharge chamber 6 in which a plurality of nozzle holes 4 for discharging ink droplets communicate, and a fluid resistance portion 7 is provided in each discharge chamber 6. A common liquid chamber (common ink chamber) 8 for supplying ink through the ink passage is formed. Note that an edge shooter type in which ink droplets are ejected from a nozzle hole provided at an end of the substrate can also be used.
[0022]
The intermediate first substrate 1 has a concave portion for forming a discharge chamber 6 having a bottom wall as a vibration plate 10 on the main substrate 11 and a common liquid chamber 8 for supplying ink to each discharge chamber 6. Having a recess. An individual electrode 14 facing the diaphragm 10 is formed below the diaphragm 10 via the gap 12, and the diaphragm 10 and the individual electrodes 14 constitute an electrostatic actuator. Further, the diaphragm 10 and the electrode 14 are electrically separated.
[0023]
Here, the diaphragm 10 is formed of, for example, a two-layer laminated film of a nitride film 10a on the electrode 14 side and a polysilicon film 10b serving as a common electrode. In this manner, by forming the diaphragm from the laminated film, as described later, in this head, the electrode and the sacrificial layer formed on the electrode after the formation of the diaphragm are etched to form the gap 12, so that the diaphragm is formed. By stacking an electrode material (here, a polysilicon film) and an insulating film (here, a nitride film) having high selectivity with respect to an etching gas as a protective film as 10, even if the electrode material has low selectivity with respect to an etching gas, The process can be used, the process selection range can be widened, and the cost can be reduced.
[0024]
Further, the gap 12 is formed by removing the sacrificial layer formed on the electrode 14 after forming the electrode 14 and the vibration plate 10, whereby the gap 12 can be controlled by the thickness of the sacrificial layer. In addition, variations in the gap 12 are reduced.
[0025]
Further, an insulating film 13 is formed on the upper surface of the electrode 14 (the surface on the side of the diaphragm 10), and an insulating film 15 is formed on the lower surface of the electrode 14 (the surface on the side opposite to the side of the diaphragm 10). An insulating film is formed on both sides. The insulating film 15 also forms a partition between the electrodes 14 and 14 (between channels).
[0026]
In this case, the total thickness of the electrode 14 and the insulating films 13 and 15 is preferably greater than the thickness of the laminated diaphragm 10, and more preferably three times or more. As described above, by sandwiching the individual electrodes between the insulating films from above and below, and making the total film thickness larger than the film thickness of the diaphragm, particularly, three times or more, the electrode portion has sufficient rigidity with respect to the diaphragm rigidity. A structure can be provided, and reliability and stability are improved.
[0027]
The second substrate 2 bonded to the lower surface of the first substrate 1 is a protection substrate for protecting the first substrate 1. When directly mounted on another pedestal having a similar function, the second substrate 2 may be omitted.
[0028]
In the second substrate 2, recesses 16 for forming cavities are formed below the individual electrodes 14 corresponding to the gaps 12, and the recesses 16 are communicated by communication grooves 17. In addition, the individual electrode 14 is partially removed to form a communication hole 18, and the gap 12 communicates with the cavity formed by the recess 16 via the communication hole 18.
[0029]
As a result, the cavity and the gap below the individual electrode communicate with each other, and the cavity acts as a re-damper in which the gas existing in the gap is compressed by the displacement of the diaphragm, thereby reducing the pressure rise in the gap when the diaphragm is displaced. The drive voltage can be reduced.
[0030]
The communication hole 18 also functions as a sacrifice layer etching hole when the gap 12 is formed by etching the sacrifice layer formed on the electrode 14 after the formation of the electrode 14 and the diaphragm 10. As a result, the sacrificial layer can be removed by etching from the entire individual electrode surface, the etching gas is easily supplied to the sacrificial layer region, and extremely long over-etching can be reduced, so that the reliability of the head can be improved and the process time can be improved. And cost can be reduced.
[0031]
Further, the air pressure correcting recess 20 is formed in the second substrate 2, and a communication hole 21 for communicating the air pressure correcting recess 20 to the outside is formed. On the other hand, the air pressure correcting recess 20 is formed in the first substrate 1. A movable plate 22 for atmospheric pressure correction that forms a wall surface is formed.
[0032]
As described above, by forming the air pressure correction concave portion 20 in the second substrate 2 and forming the communication hole 21 communicating the outside with the outside, the air pressure correction concave portion 20, the concave portion 16, After the dry air or the like is sealed in the gap 12, the communication hole 21 can be closed, so that the structure is not affected by the external environment, and the reliability of the droplet discharge head can be further improved. is there.
[0033]
In addition, it is preferable that the movable plate 22 for air pressure correction facing the concave portion 20 for air pressure correction be formed in a size having a shorter side length than the vibration plate 10 of the head part in order to reduce the rigidity of the vibration plate. It is preferable that the head is formed so as to be displaced more sensitively than the diaphragm 10 of the head.
[0034]
The third substrate 3 bonded to the upper surface of the first substrate 1 is a nickel substrate having a thickness of 50 microns, and a nozzle hole 4 and a common liquid are provided on the surface of the substrate 3 so as to communicate with the discharge chamber 6. A groove 7 serving as a fluid resistance for connecting the chamber 8 to the discharge chamber 6 is provided, and an ink supply port 9 is provided for communicating with the common ink chamber 8.
[0035]
The operation of the ink jet head thus configured will be described. When a pulse potential of 40 V is applied from the oscillation circuit (drive circuit) to the individual electrode 14 in a state where the ejection chamber 6 is filled with the ink, the surface of the individual electrode 14 is charged to a positive potential, and a static potential is formed between the individual electrode 14 and the diaphragm 10. The power acts, and the diaphragm 10 bends toward the individual electrode 14 side. As a result, the pressure in the discharge chamber 6 decreases, and ink flows from the common liquid chamber 8 into the discharge chamber 6 via the fluid resistance portion 7.
[0036]
Thereafter, when the pulse voltage to the individual electrode 14 is set to 0 V, the diaphragm 10 bent downward by the electrostatic force returns to its original state due to its rigidity. As a result, the pressure in the ejection chamber 6 rapidly rises, and the ink droplets 23 are ejected from the nozzle holes 4 toward the recording paper 24 as shown in FIG. By repeating this, ink droplets can be continuously ejected.
[0037]
Here, the force F acting between the diaphragm 10 as an electrode and the individual electrode 14 increases in inverse proportion to the square of the distance d between the electrodes as shown in the following equation (1). In order to drive at a low voltage, it is important to narrow the gap (gap length) between the individual electrode 14 and the gap 12 between the diaphragm 10.
[0038]
(Equation 1)

[0039]
In the equation (1), F is a force acting between electrodes, ε is a dielectric constant, S is an area of a surface facing the electrodes, d is a distance between the electrodes, and V is an applied voltage.
[0040]
Next, a first embodiment of the method of manufacturing the ink jet head will be described with reference to FIGS. 3 and 4 are cross-sectional explanatory views for explaining the same manufacturing method, and FIG. 5 is a plan explanatory view of the same.
[0041]
In this embodiment, an electrostatic actuator is manufactured by forming a diaphragm material and an electrode material on the first substrate 1 on which a liquid chamber (discharge chamber) 6 is to be formed later.
First, as shown in FIG. 3A, a nitride film 10a serving as the diaphragm 10 is formed on the surface of a silicon substrate 31 having a plane orientation (110) serving as the main substrate 11 constituting the first substrate 1 with a thickness of 0.2 μm. The polysilicon film 10b serving as a common electrode is formed to a thickness of 0.1 μm, and in the present embodiment, the oxide film 10c is formed to a thickness of 0.8 μm.
[0042]
The film thickness is not limited to the above value, and may be set to an optimum value in consideration of the diaphragm rigidity due to the gap interval and the shorter side length of the diaphragm. Further, since the common electrode is sandwiched between insulating films (here, the nitride film 10a and the oxide film 10c), almost any conductive film can be used.
[0043]
Then, a polysilicon 32 is formed to a thickness of 0.5 μm on the oxide film 10c. The polysilicon 32 is a material to be used as a sacrificial layer, and since this film thickness becomes a gap interval, the film thickness is not limited to the above value and may be set to an optimum film thickness similarly to the film thickness of the diaphragm material.
[0044]
Further, an oxide film 33 serving as the insulating film 13 and the individual electrodes 14 are formed on the polysilicon 32. As a material of the individual electrode 14, polysilicon, Al, TiN, Ti, W, ITO, or the like can be used.
[0045]
Next, the individual electrode 14 is patterned into an electrode shape by a litho / etch method, and the oxide film 33 and the polysilicon 32 are also patterned into a required shape.
[0046]
Then, as shown in FIG. 2B, an oxide film 35 serving as the insulating film 15 is formed to a thickness of 5 μm on the oxide film 33 including the surface of the individual electrode 14 and the exposed surface of the oxide film 10c by the CVD method. The film is polished to a thickness of about 1 μm by a CMP method to flatten the surface. Here, planarization by the CMP method is not always necessary. The film thickness of the oxide film 35 is sufficiently larger than the film thickness of the diaphragm 10, and the film rigidity of the total film thickness of the oxide film 33, the individual electrodes 14, and the oxide film 35 is at least a laminated film. Preferably, the film thickness is 10 times or more the rigidity of 10.
[0047]
Next, as shown in FIG. 5C and FIG. 5, in order to form a removal hole (communication hole) 18 for removing the polysilicon 32 as the sacrificial layer, the oxide film 33 is formed by a litho / etch method. The electrode 14 and the oxide film 35 are patterned. Note that an electrode pad portion 14a is also formed on the individual electrode 14, as shown in FIG. Thereafter, oxidation is performed to form an oxide film on the surface of the individual electrode 14 exposed on the side surface of the removal hole 18, and SF is formed. ₆ Polysilicon 32 is removed by isotropic dry etching using.
[0048]
Here, since the structure surrounding the polysilicon 32 serving as the sacrifice layer is surrounded by the oxide film 35, the sacrifice layer can be removed under a sacrifice layer etching condition having high selectivity with respect to the oxide film 35, and a gap can be accurately formed. can do. As a method for removing the polysilicon 32 as the sacrificial layer, wet etching using TMAH may be used, or XF ₂ Normal pressure dry etching using gas may be used.
[0049]
Further, here, as shown in FIG. 5, the sacrificial layer removing holes 18 are arranged in a grid, but the sacrificial layer removing holes 18 are uniformly arranged on the electrode surface in order to efficiently remove the sacrificial layer. The arrangement pattern is not limited to this. However, arranging a large number of the removal holes 18 leads to a reduction in the area of the individual electrodes 14 and weakening of the electrostatic force between the electrodes. It is necessary to select the optimal arrangement.
[0050]
Thereafter, as shown in FIG. 4A, a protection substrate (second substrate) 2 having a recess 16 and a communication groove 17 formed in a portion corresponding to the gap 12 is attached to a silicon substrate 31 with an adhesive 36, and A nitride film 37 is formed on the surface, a liquid chamber pattern is formed on the nitride film 37 by a litho / etch method, and the silicon substrate is wet-etched with KOH using the pattern of the nitride film 37 as a mask as shown in FIG. A discharge chamber (liquid chamber) 6 is formed in 31.
[0051]
The liquid chamber 6 is formed by SF ₆ It is also possible to form by dry etching by ICP etching using gas, but in this case, a mask is an oxide film instead of the nitride film 37, and an oxide film 10c is formed before the nitride film 10a is formed. By forming a laminated diaphragm having a layer structure, the liquid chamber 6 can be formed using the oxide film as a mask. In this case, the silicon substrate 31 can be a substrate having a plane orientation (100), and the material cost can be reduced.
[0052]
By using polysilicon as the sacrificial layer, the sacrificial layer can be removed using the etching material used in semiconductor manufacturing, and a silicon oxide film having high etching resistance is formed on the upper and lower sides. As a result, a manufacturing process with less variation can be achieved, and mass production at low cost becomes possible.
[0053]
Further, a silicon oxide film can be used as the sacrificial layer instead of polysilicon. In this case, it is preferable to use polysilicon as a protective film of the silicon oxide film. In this case, the sacrificial layer oxide film is removed by a wet etch method, an HF vapor method, a chemical dry etching method, or the like, and then the polysilicon surface is oxidized as a protective film to form an insulating layer.
[0054]
In this way, by using the silicon oxide film as the sacrificial layer, the sacrificial layer can be removed using the etching material used in the semiconductor manufacturing, and a polysilicon film having high etching resistance is formed vertically. By doing so, a manufacturing process with less variation can be achieved, and mass production at low cost becomes possible.
[0055]
Also, using a resist as a sacrificial layer acid, ₂ A method of removing with a plasma or a stripping solution, a method of removing with a organic material using a polymer material for the sacrificial layer, a method of removing with a chemical solution such as KOH using aluminum for the sacrificial layer, and a method of removing NH3 using TiN for the sacrificial layer ₃ OH and H ₂ O ₂ A similar process can be assembled by various combinations such as a method of removing with a chemical solution such as a mixed solution.
[0056]
Although not shown in the drawing, the nozzle plate 3 is finally adhered to the surface of the substrate 31 to complete the electrostatic droplet discharge head.
[0057]
In the droplet discharge head manufactured by the above-described manufacturing process, the gap interval is defined by the thickness of the sacrificial layer, so that the gap can be formed with high accuracy and little variation. In addition, since direct bonding and anodic bonding are not required and most can be formed by a semiconductor process, a stable droplet discharge head with good yield can be manufactured.
[0058]
Next, a second embodiment of the ink jet head which is a droplet discharge head according to the present invention will be described with reference to FIGS. 6 and 7 are cross-sectional explanatory views for explaining the manufacturing method, and FIG. 8 is a plan explanatory view of the same.
[0059]
In the present embodiment, the sacrifice layer is removed from the diaphragm surface, and the sacrifice layer removal hole is sealed with a photosensitive polyimide and a liquid chamber is formed.
First, as shown in FIG. 6A, a thermal oxide film 45 is formed to a thickness of about 1.0 μm on a silicon substrate 41 having a (100) plane orientation, and then a polysilicon 44 serving as an individual electrode is formed to a thickness of 0.5 μm. The film is formed to a thickness. After doping the polysilicon 44 with phosphorus to reduce the resistance, an electrode isolation groove 44b is formed by a litho-etch method, and then a high-temperature oxide film (HTO film) 43 is formed to a thickness of 0.25 μm. Note that an electrode pad portion 44a is also formed on the polysilicon 44 serving as an individual electrode as shown in FIG.
[0060]
Next, as shown in FIG. 7B, a polysilicon 42 serving as a sacrificial layer is formed to a thickness of 0.5 μm on the HTO film 43, and then a separation groove 42a is formed by a litho-etching method. (HTO film) 50c is formed to a thickness of 0.1 μm.
[0061]
Further, as shown in FIG. 3C, a polysilicon 50b serving as a common electrode is formed to a thickness of 0.5 μm, and an oxide film 50a serving as a diaphragm protection film is formed to a thickness of 0.5 μm. Thereafter, in order to form the sacrificial layer removing hole 51 in a region which will later become the liquid chamber spacing wall by the lithoetch method, a pattern oversized from the sacrificial layer removing hole 51 is formed by the lithoetch method, and the oxide film 50a and the polysilicon 50b are formed. Etching is performed in order. Thereafter, oxidation is performed to form an oxide film 50b1 on the surface of the polysilicon 50b exposed on the side surface of the removal hole 51.
[0062]
Thereafter, as shown in FIGS. 7A and 8, the removal hole 51 is patterned by a litho-etching method, and the oxide film 50 c is removed by etching. ₆ The gap 52 is formed by removing the sacrifice layer 42 by isotropic dry etching using. Note that, similarly to the first embodiment, wet etching using TMAH may be used, or XF ₂ Normal pressure dry etching using gas may be used.
[0063]
Next, as shown in FIG. 7B, a photosensitive polyimide 53 is formed into a film having a thickness of 100 μm by spin coating on a portion serving as a liquid chamber spacing wall, and the liquid chamber 56 is formed by sealing the sacrifice layer removing hole 51 and exposing and developing. Is formed. Thereafter, baking is performed at 350 ° C. for 5 hours to cure the polyimide 53 to form a liquid chamber spacing wall.
[0064]
Although not shown in the drawing, the nozzle plate 3 is finally attached to the surface of the polyimide 53 to complete the electrostatic liquid droplet ejection head.
[0065]
In this case, the diaphragm 50 is composed of an oxide film 50a, polysilicon 50b, and an HTO film 50c. The diaphragm 50 is partially formed by a removal hole 51 in the region of the liquid chamber spacing wall corresponding to the partition region between the gaps 52. Is removed.
[0066]
That is, since the diaphragm is partially removed to form the sacrificial layer removal hole in the partition region, the sacrificial layer can be removed without affecting the diaphragm constituting one wall of the discharge chamber, and the reliability is improved. Droplet discharge head, and the cost can be further reduced because there is no need for a protective substrate for protecting the lower electrode.
[0067]
Further, in the droplet discharge head manufactured by the above manufacturing process, since the gap interval is defined by the thickness of the sacrificial layer, it is possible to form the gap with high accuracy and little variation. In addition, since no direct bonding or anodic bonding is required, a droplet discharge head can be constituted by two substrates, and a further low-cost head can be manufactured. In addition, since most can be formed by a semiconductor process, a stable droplet discharge head with good yield can be obtained.
[0068]
Next, an ink cartridge integrated type head of a droplet discharge head according to the present invention will be described with reference to FIG.
The ink cartridge integrated type head 100 is obtained by integrating the ink jet head 102 having any of the above-described embodiments having the nozzle holes 101 and the like, and the ink tank 103 that supplies ink to the ink jet head 101. .
[0069]
As described above, by integrating the ink tank that supplies ink to the droplet discharge head according to the present invention, an ink cartridge (integrated with a droplet discharge head having high droplet discharge efficiency and stable droplet discharge characteristics) can be obtained. An ink tank integrated head) is obtained.
[0070]
Next, an example of a mechanism of an ink jet recording apparatus equipped with an ink jet head (including a head-integrated ink cartridge) according to the present invention will be described with reference to FIGS. FIG. 11 is a perspective view of the recording apparatus, and FIG. 12 is a side view of a mechanism of the recording apparatus.
[0071]
The inkjet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 111, a recording head including the inkjet head according to the present invention mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. A paper cassette (or a paper tray) 114 capable of loading a large number of sheets 113 from the front side is detachably attached to a lower portion of the apparatus main body 111. The manual feed tray 115 for manually feeding the paper 113 can be opened, and the paper 113 fed from the paper feed cassette 114 or the manual feed tray 115 is taken in. After the image is recorded, the sheet is discharged to a sheet discharge tray 116 mounted on the rear side.
[0072]
The printing mechanism 112 holds the carriage 123 slidably in the main scanning direction (the direction perpendicular to the paper surface in FIG. 15) by a main guide rod 121 and a sub guide rod 122, which are guide members laterally mounted on left and right side plates (not shown). On the carriage 123, a head 124 composed of an inkjet head, which is a droplet discharge head according to the present invention, which discharges ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction intersecting the main scanning direction with a plurality of ink ejection ports, and are mounted with the ink droplet ejection direction facing downward. Each ink cartridge 125 for supplying each color ink to the head 124 is exchangeably mounted on the carriage 123.
[0073]
The ink cartridge 125 has an upper air port that communicates with the atmosphere, a lower supply port for supplying ink to the inkjet head, and a porous body filled with ink inside. Maintains the ink supplied to the inkjet head at a slight negative pressure.
[0074]
Further, although the heads 124 of each color are used as the recording heads here, a single head having nozzles for ejecting ink droplets of each color may be used.
[0075]
Here, the carriage 123 is slidably fitted on the main guide rod 121 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the front guide rod 122 on the front side (upstream side in the paper conveyance direction). are doing. In order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between a drive pulley 128 and a driven pulley 129 which are driven to rotate by a main scanning motor 127. , And the carriage 123 is reciprocally driven by forward and reverse rotation of the main scanning motor 127.
[0076]
On the other hand, in order to convey the paper 113 set in the paper feed cassette 114 to the lower side of the head 124, the paper 113 is guided by a paper feed roller 131 and a friction pad 132 for separating and feeding the paper 113 from the paper feed cassette 114. A guide member 133, a transport roller 134 that transports the fed paper 113 in a reversed state, a transport roller 135 pressed against the peripheral surface of the transport roller 134, and a leading end that defines an angle at which the paper 113 is fed from the transport roller 134. A roller 136 is provided. The transport roller 134 is driven to rotate by a sub-scanning motor 137 via a gear train.
[0077]
Further, an image receiving member 139 is provided as a paper guide member for guiding the paper 113 sent from the transport roller 134 below the recording head 124 in accordance with the movement range of the carriage 123 in the main scanning direction. On the downstream side of the printing receiving member 139 in the paper transport direction, there are provided a transport roller 141 and a spur 142 which are driven to rotate to transport the paper 113 in the paper discharge direction. Rollers 143 and spurs 144 and guide members 145 and 146 forming a paper discharge path are provided.
[0078]
At the time of recording, the recording head 124 is driven in accordance with an image signal while moving the carriage 123, thereby ejecting ink to the stopped paper 113 to record one line, and after transporting the paper 113 by a predetermined amount, Record the line. Upon receiving a recording end signal or a signal indicating that the rear end of the sheet 113 has reached the recording area, the recording operation is terminated and the sheet 113 is discharged. In this case, the inkjet head according to the present invention, which forms the head 124, has improved controllability of ink droplet ejection and suppresses characteristic fluctuation, so that an image of high image quality can be stably recorded.
[0079]
In addition, a recovery device 147 for recovering the ejection failure of the head 124 is disposed at a position outside the recording area on the right end side in the moving direction of the carriage 123. The recovery device 147 has a cap unit, a suction unit, and a cleaning unit. The carriage 123 is moved to the recovery device 147 side during printing standby, the head 124 is capped by the capping means, and the ejection port is kept in a wet state, thereby preventing ejection failure due to ink drying. In addition, by discharging ink that is not related to printing during printing or the like, the ink viscosity of all the discharge ports is kept constant, and stable discharge performance is maintained.
[0080]
In the event of a discharge failure, for example, the discharge port (nozzle) of the head 124 is sealed by a capping unit, and air bubbles and the like are sucked out of the discharge port by a suction unit through a tube, and ink or dust adhered to the discharge port surface. Is removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) provided at a lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.
[0081]
As described above, since the inkjet recording apparatus is equipped with the inkjet head, which is the droplet discharge head according to the present invention, a recording apparatus capable of recording an image of high image quality at low cost can be obtained.
[0082]
Next, a micropump as a microdevice to which the actuator portion of the droplet discharge head according to the present invention is applied will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of a main part of the micropump.
This micropump has a flow path substrate 201 and an actuator substrate 202. The flow path substrate 201 has a flow path 203 through which a fluid flows. The actuator substrate 202 includes a deformable movable plate 204 (corresponding to a diaphragm of a head) that forms a wall surface of the flow path 201 on a support substrate 210, and a movable portion 204a (not fixed) of the movable plate 204. (A part) is provided with an electrode 206 which is opposed via a gap 205.
[0083]
Although not shown in detail, the movable plate 204 is formed of a laminated film in which both surfaces of a common electrode material are sandwiched between insulating films, as described in the embodiment of the inkjet head. Further, insulating films 207 and 208 are formed on both surfaces of the electrode 206, respectively.
[0084]
The principle of operation of this micropump will be described. As in the case of the above-described inkjet head, by selectively applying a pulse potential to the electrode 206, an electrostatic attraction force is generated between the movable plate 204 and the electrode 206. The movable portion 204a of the plate 204 is deformed toward the electrode 206. Here, by sequentially driving the movable portion 204a of the movable plate 204 from the right side in the drawing, the fluid in the flow path 203 flows in the direction of the arrow, and the fluid can be transported.
[0085]
In this case, by providing the actuator of the droplet discharge head according to the present invention, a small-sized and low-power-consumption micropump can be obtained. Although an example in which the movable plate has a plurality of movable portions is shown here, one movable portion may be provided. In addition, one or more valves, for example, a check valve or the like can be provided between the movable parts to increase the transportation efficiency.
[0086]
Next, an example of an optical device to which the actuator portion of the droplet discharge head according to the invention is applied will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of the device.
This optical device has an actuator substrate 302 including a deformable mirror 301. It is preferable to form a dielectric multilayer film or a metal film on the surface of the mirror 301 to increase the reflectance.
[0087]
The actuator substrate 302 opposes a deformable mirror 301 (corresponding to a diaphragm of the head) on a support substrate 310 and a movable portion 301 a (unfixed portion) of the mirror 301 via a gap 305. And an electrode 306. Note that insulating films 307 and 308 are formed on both surfaces of the electrode 306, respectively.
[0088]
The principle of this optical device will be described. As in the case of the above-described ink jet head, by selectively applying a pulse potential to the electrode 306, electrostatic attraction between the electrode 306 and the movable portion 301a of the mirror 301 facing the electrode 306 is performed. Since a force is generated, the movable portion 301a of the mirror 301 is deformed into a concave shape to form a concave mirror. Therefore, when the light from the light source 310 irradiates the mirror 301 via the lens 311, when the mirror 301 is not driven, the light is reflected at the same angle as the incident angle, but when the movable part 301 a of the mirror 301 is driven, Since the movable part 301a becomes a concave mirror, the reflected light becomes divergent light. Thereby, an optical modulation device can be realized.
[0089]
The provision of the actuator of the droplet discharge head according to the present invention makes it possible to obtain a compact optical device with low power consumption.
[0090]
Therefore, an example in which this optical device is applied will be described with reference to FIG. In this example, the above-described optical devices are arranged two-dimensionally, and the movable portions 301a of each mirror 301 are independently driven. Although a 4 × 4 arrangement is shown here, more arrangements are possible.
[0091]
Therefore, similarly to FIG. 13 described above, the light from the light source 310 is applied to the mirror 301 via the lens 311, and the light that enters the place where the mirror 301 is not driven enters the projection lens 312. On the other hand, the portion where the movable portion 301a of the mirror 301 is deformed by applying a voltage to the electrode 306 becomes a concave mirror, so that light diverges and hardly enters the projection lens 312. The light incident on the projection lens 312 is projected on a screen (not shown) or the like, and an image can be displayed on the screen.
[0092]
In the above embodiment, an example in which the droplet discharge head is applied to an inkjet head has been described. However, as a droplet discharge head other than the inkjet head, for example, a droplet discharge head that discharges a liquid resist as a droplet, a DNA The present invention can be applied to other droplet discharge heads such as a droplet discharge head that discharges the sample as droplets. In addition to micro pumps and optical devices (optical modulation devices), actuators that constitute the droplet discharge head include micro switches (micro relays), multi-optical lens actuators (optical switches), micro flow meters, and pressure sensors. Can also be applied.
[0093]
【The invention's effect】
As described above, according to the droplet discharge head according to the present invention, the gap between the diaphragm and the electrode is formed by removing the sacrificial layer formed on the electrode after the formation of the electrode and the diaphragm. Therefore, variations in the gap are reduced, and variations in characteristics are reduced and high reliability is obtained.
[0094]
The method for manufacturing a droplet discharge head according to the present invention is a method for manufacturing the droplet discharge head according to the present invention, and has a configuration in which polysilicon or a silicon oxide film is used for the sacrificial layer, so that the cost of the head can be reduced. Can be achieved.
[0095]
According to the inkjet recording apparatus of the present invention, since the inkjet head for ejecting ink droplets is configured to be the droplet ejection head of the present invention, high-quality recording can be performed.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an inkjet head according to a first embodiment of a droplet discharge head of the present invention.
FIG. 2 is an explanatory cross-sectional view of the head taken along a lateral direction of a diaphragm.
FIG. 3 is an explanatory cross-sectional view for explaining a first embodiment of a method for manufacturing an ink-jet head which is a droplet discharge head according to the present invention;
FIG. 4 is an explanatory sectional view illustrating a step following FIG. 3;
FIG. 5 is an explanatory plan view for explaining the same step;
FIG. 6 is an explanatory cross-sectional view for explaining a second embodiment of an ink jet head which is a droplet discharge head of the present invention and a method of manufacturing the same.
FIG. 7 is an explanatory sectional view illustrating a step following FIG. 6;
FIG. 8 is an explanatory plan view for explaining the same step;
FIG. 9 is a perspective explanatory view for explaining an ink cartridge integrated type head including a droplet discharge head according to the present invention.
FIG. 10 is a perspective explanatory view illustrating an example of an ink jet recording apparatus according to the present invention.
FIG. 11 is an explanatory diagram of a mechanism section of the recording apparatus.
FIG. 12 is an explanatory view illustrating an example of a micropump to which the actuator portion of the droplet discharge head according to the invention is applied.
FIG. 13 is an explanatory diagram illustrating an example of an optical device to which the actuator portion of the droplet discharge head according to the invention is applied.
FIG. 14 is an explanatory perspective view illustrating an example of a light modulation device using the optical device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 2 ... 2nd board | substrate, 3 ... nozzle plate, 4 ... nozzle hole, 6 ... discharge chamber, 7 ... fluid resistance part, 8 ... common liquid chamber, 10 ... diaphragm, 12 ... gap, 14 ... Electrodes, 100: ink cartridge integrated head, 124: recording head, 201: flow path substrate, 203: flow path, 204a: movable part, 206: electrode, 301: mirror, 304a: movable part, 306: electrode.

Claims (12)

A diaphragm that forms at least one wall surface of a pressurized chamber to which a nozzle that discharges a droplet communicates, and an electrode that faces the diaphragm through a gap, and deforms the diaphragm by electrostatic force to form the liquid. In the droplet discharge head for discharging droplets, the gap between the diaphragm and the electrode is formed by removing a sacrificial layer formed on the electrode after the formation of the electrode and the diaphragm. A droplet discharge head characterized by the above-mentioned. 2. The droplet discharge head according to claim 1, wherein the diaphragm is formed of a laminated film of two or more layers. 3. The droplet discharge head according to claim 1, wherein the electrode is partially removed. The droplet discharge head according to claim 1, further comprising a cavity below the electrode, wherein the gap communicates with the cavity. 5. The droplet discharge head according to claim 1, wherein an insulating film is provided on both surfaces of the electrode, and a total thickness of the electrode and the insulating film is larger than a thickness of the laminated diaphragm. 6. Characteristic droplet discharge head. 3. The droplet discharge head according to claim 1, wherein the diaphragm is partially removed in a partition region between a plurality of gaps that are continuously arranged. The method for manufacturing a droplet discharge head according to any one of claims 1 to 6, wherein polysilicon is used for the sacrificial layer. 8. The method according to claim 7, wherein a silicon oxide film is formed above and below the sacrificial layer film made of polysilicon. The method for manufacturing a droplet discharge head according to any one of claims 1 to 6, wherein a silicon oxide film is used for the sacrificial layer. 10. The method of manufacturing a droplet discharge head according to claim 9, wherein polysilicon is formed above and below the sacrificial layer film made of the silicon oxide film. The droplet discharge head according to any one of claims 1 to 6, wherein an ink tank for supplying ink is integrated. An inkjet recording apparatus comprising an inkjet head for ejecting ink droplets, wherein the inkjet head is the droplet ejection head according to any one of claims 1 to 6, and 11.

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