JP2004090575A - Process for manufacturing inkjet recording head, inkjet recording head, and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for manufacturing an inkjet recording head in which manufacturing yield is increased and variation in the ejection quantity of ink can be limited to an extremely small range by enhancing flatness of the surface of a coating resin layer. <P>SOLUTION: An ink channel pattern 3 formed of a soluble resin on a basic body is coated with a solvent for forming a coating resin layer 4 becoming an ink channel wall and then the coating resin layer 4 is held in the state of reduced pressure thus accelerating removal of the solvent in the coating resin forming the coating resin layer 4. Furthermore, flatness of the surface of the coating resin layer 4 is enhanced by employing a solvent containing 2-ethoxyethanol as the solvent in the coating resin forming the coating resin layer 4. <P>COPYRIGHT: (C)2004,JPO

Description

【００３１】
次に、図４（ａ）および（ｂ）のように吐出口５を形成する。本例の場合、被覆樹脂層４は、光カチオン重合開始剤を含み、ネガ型の感光特性が付与されているため、フォトリソグラフィーによって吐出口５を形成する。すなわち、キャノン製マスクアライナーＭＰＡ６００を用い、マスクを介してパターン露光（露光時間５０秒）を行い、次いで９０℃の温度で４分間加熱処理を行った後に、現像処置を施して吐出口５を形成した。吐出口５の径は、φ２０μｍに形成した。
【００３２】
次に、シリコン基板１の裏面から、マスクを介してシリコンの異方性エッチングを行い、図５（ａ）および（ｂ）のようなインク供給口６を形成した。
【００３３】
次に、現工程において残存しているインク流路パターン３を全面露光により分解した後、図６（ａ）および（ｂ）のように、それを乳酸メチルによって除去した。
【００３４】
その後、被覆樹脂層４を完全に硬化させるために、２００℃の温度で１時間の加熱処理をしてから、電気的接続およびインク供給部材を配置して、インクジェット記録ヘッドを完成させた。
【００３５】
このように製作された本実施例の記録ヘッドの比較対象として、被覆樹脂層４の回転塗布の終了後に、それを減圧下に保持せずに、常圧下において９０℃の温度で３分間ベークして、塗布溶媒の乾燥を行ったサンプルを作成した。そのサンプルに対する処理において、被覆樹脂層４の回転塗布終了後に減圧下での保持がない以外は、上述した実施例の記録ヘッドに対する処理と同様である。
【００３６】
本実施例の記録ヘッド、つまり被覆樹脂層４の回転塗布終了後に減圧下において保持された記録ヘッドの場合、所定パターンの画像を記録する記録検査の結果、歩留まりは９５％であった。不良の５％について解析を行ったところ、顕微鏡観察では、ゴミ等は検出されず原因は特定できなかった。
【００３７】
一方、比較対象としてのサンプル、つまり被覆樹脂層４の回転塗布終了後に減圧下に保持しなかった記録ヘッドの場合、本実施例の記録ヘッドと同様の記録検査の結果、歩留まりは８１％であった。不良の１９％について解析を行ったところ、顕微鏡観察においては、薄膜状のゴミによる不良が１３％、ゴミ等は検出されずに原因が特定できなかったものが６％であった。その薄膜状のゴミは、インク流路パターン３と被覆樹脂層４の相溶物と考えられる。
【００３８】
（第１の実施形態の実施例２）
本実施例では、２４μｍ角の電気熱変換素子２を２列配した。その電気熱変換素子２は３００ノズル分配置され、その配備形態は、６００ＤＰＩのピッチで２列、かつ千鳥状に配されており、記録ヘッドとして１２００ＤＰＩの３００ノズルが形成できるようになっている。なお、基板１は、シリコン基板用素材に２５０チップ分配列される。
【００３９】
このような基板１を用いて、前述した実施例１と同様の方法によって記録ヘッドを作成した。ただし、塗布溶媒としてキシレンを用い、前述した表１の被覆樹脂組成物を４５ｗｔ％の濃度で溶解して、スピンコートにより、インク流路パターン３上に塗布した。その塗布は、被覆樹脂層４が１２μｍとなるように、スピン回転数を調整しながら行う。その回転塗布の終了後、１０ｃｍＨｇの減圧下において、４０℃の温度で３分間保持してから、最後に常圧下にて９０℃の温度で３分間ベークして、塗布溶媒の乾燥を行った。なお、吐出口５の径は、φ１５μｍとした。
【００４０】
このように製作された本実施例の記録ヘッドの比較対象として、被覆樹脂層４の回転塗布の終了後に、減圧下に保持せずに、常圧下において９０℃の温度で３分間ベークして、塗布溶媒の乾燥を行ったサンプルを作成した。
【００４１】
本実施例の記録ヘッド、つまり被覆樹脂層４の回転塗布終了後に減圧下において保持された記録ヘッドの場合、所定パターンの画像を記録する記録検査の結果、歩留まりは９３％であった。不良の７％について解析を行ったところ、顕微鏡観察では、２％の記録ヘッドに糸状のゴミ等が検出され、残りの記録ヘッドに関してはゴミ等が検出されず原因は特定できなかった。その糸状のゴミは、組立て工程中に混入したと思われるゴミであり、前述した実施例１の比較例としてのサンプルにおいて検出された薄膜状のゴミとは明らかに形態が異なっていた。
【００４２】
一方、比較対象としてのサンプル、つまり被覆樹脂層４の回転塗布終了後に減圧下に保持しなかった記録ヘッドの場合、本実施例の記録ヘッドと同様の記録検査の結果、歩留まりは８５％であった。不良の１５％について解析を行ったところ、顕微鏡観察においては、薄膜状のゴミによる不良が１０％、ゴミ等は検出されずに原因が特定できなかったものが５％であった。その薄膜状のゴミは、インク流路パターン３と被覆樹脂層４の相溶物と考えられる。
【００４３】
（第１の実施形態の実施例３）
本実施例では、前述した実施例１と同様に記録ヘッドを作成した。ただし、塗布溶媒として、メチルイソブチルケトン／ジグライム＝１／１（ｗｔ）を用い、下表２の被覆樹脂組成物を５０ｗｔ％の濃度で溶解して、スピンコートにより、インク流路パターン３上に塗布した。その塗布は、被覆樹脂層４が１２μｍとなるように、スピン回転数を調整しながら行う。その回転塗布の終了後、５ｃｍＨｇの減圧下において、４０℃の温度で３分間保持してから、最後に常圧下にて９０℃の温度で３分間ベークして、塗布溶媒の乾燥を行った。なお、吐出口５の径は、φ２０μｍとした。また、その吐出口５の形成に際しては、露光時間を６０秒とした。
【００４４】
【表２】

【００４５】
このように製作された本実施例の記録ヘッドの比較対象として、被覆樹脂層４の回転塗布の終了後に、減圧下に保持せずに、常圧下において９０℃の温度で３分間ベークして、塗布溶媒の乾燥を行ったサンプルを作成した。
【００４６】
本実施例の記録ヘッド、つまり被覆樹脂層４の回転塗布終了後に減圧下において保持された記録ヘッドの場合、所定パターンの画像を記録する記録検査の結果、歩留まりは８２％であった。不良の１８％について解析を行ったところ、顕微鏡観察では、薄膜状のゴミ等は検出されなかった。
【００４７】
一方、比較対象としてのサンプル、つまり被覆樹脂層４の回転塗布終了後に減圧下に保持しなかった記録ヘッドの場合、本実施例の記録ヘッドと同様の記録検査の結果、歩留まりは７５％であった。不良の２５％について解析を行ったところ、顕微鏡観察において、薄膜状のゴミによる不良が１８％検出された。その薄膜状のゴミは、インク流路パターン３と被覆樹脂層４の相溶物と考えられる。
【００４８】
以上の実施例１，２，３から明らかなように、塗布溶媒の種類に拘わらず、被覆樹脂層４の回転塗布終了後に減圧下に保持した記録ヘッドと、被覆樹脂層４の回転塗布終了後に減圧下に保持しなかった記録ヘッドの記録検査の結果、インク流路パターン３と被覆樹脂層４の相溶物と考えられる薄膜状のゴミの出現率に大きな差が生じて、歩留まりに差が生じた。
【００４９】
（第２の実施形態）
以下、本発明の第２の実施形態について説明する。
【００５０】
本実施形態は、前述した第１の実施形態と同様に、図１から図６と同様の手順によって記録ヘッドを製造する。本実施形態は、図３（ａ）および（ｂ）の製造段階、つまり、エポキシ樹脂を含む被覆樹脂を溶媒に溶解し、スピンコート等のソルベントコート法によって、それをインク流路パターン３上に塗布して被覆樹脂層４を形成する製造段階において、その被覆樹脂層４の膜厚精度の観点から、その塗布溶媒を選定した。
【００５１】
すなわち、まず、インク流路パターン３は、多くの場合１０μｍ以上の膜厚を有するため、被覆樹脂層４は、少なくとも１０μｍ以上の凹凸を吸収して、その表面がフラットになるように形成しなければならない。図３（ａ）および（ｂ）において、電気熱変換素子２上のインク流路パターン３の膜厚と被覆樹脂層４の膜厚との合計分の距離Ｌは、前述したＯＨ距離、つまり電気熱変換素子２とオリフィス（インク吐出口の形成面）との間の距離となり、前述したように、ノズル毎の特性のばらつきを抑える上において、そのＯＨ距離を正確に設定することが重要となる。前者のインク流路パターン３の膜厚管理に関しては、基本的にほぼフラットな基板１上にインク流路パターン３を形成するため、通常のスピンコート法等によって充分な膜厚精度を出すことができる。問題は、後者の被覆樹脂層４の膜厚管理である。
【００５２】
前述した特開平６−２８６１４９号公報には、溶解可能な樹脂によって形成されたインク流路パターン３上に、エポキシ樹脂を含む被覆樹脂層４を形成する際に、被覆樹脂を濃度３０〜７０ｗｔ％で塗布溶媒に溶解し、それをソルベントコートによって形成する方法が記載されている。本発明者による詳細な検討の結果、より高精度に被覆樹脂層４の膜厚を管理するためには、被覆樹脂の固形分濃度と併せて、塗布溶媒の選定の必要性が判明した。塗布溶媒の選定に当たっては、考慮しべき事項として、溶解可能な流路パターン３を溶解、変形させないこと、およびエポキシ樹脂を含む被覆樹脂を必要な固形分濃度まで溶解させること等、厚膜の精度以外にも考慮するべき事項がある。本発明者の検討によれば、塗布溶媒として、２−エトキシエタノール（商品名：エチルセルソルブ）が最適であることが判明した。
【００５３】
以下、本発明の第２の実施形態における具体的な実施例について説明する。
【００５４】
（第２の実施形態の実施例１）
本実施例では、前述した図１から図６に示される手順にしたがって、インクジェット記録ヘッドを製作した。まず、シリコン基板１上に、図１に示すような形態で、３０μｍ角の電気熱変換素子（窒化タンタル　ＴａＮ）２を２列配した。電気熱変換素子２は２５６ノズル分配置され、その配備形態は、３００ＤＰＩのピッチで２列、かつ千鳥状に配されており、記録ヘッドとして６００ＤＰＩの２５６ノズルが形成できるようになっている。なお、基板１は、シリコン基板用素材に２００チップ分配列される。
【００５５】
次に、図２（ａ）および（ｂ）のような溶解可能なインク流路パターン３を形成するために、ポジ型レジストＯＤＵＲ１０１０（東京応化工業社製）をスピンコートを用いて塗布し、成膜した。その後、キャノン製マスクアライナーＰＬＡ６２０（ｄｅｅｐ　ＵＶ対応）により、マスクを介してパターン露光（露光時間３分）を行い、それから現像処理を行ってインク流路パターン３を形成した。そのインク流路パターン３の設計形状は、図７（図１のＢ―Ｂ′線に沿う断面図に相当）のとおりであり、幅が３３μｍ、、膜厚が１３μｍである。また、電気熱変換素子２の幅は３０μｍ、隣接する電気熱変換素子２の間隔は８４．５μｍである。
【００５６】
１つの基板（１チップ）１内の１０ノズルのインク流路パターン３の膜厚を１０個の基板分（１０チップ分）、つまり計１００ノズル分のインク流路パターン３の膜厚を膜厚計（λエース）によって測定した結果、その膜厚平均が１３．１μｍ（バラツキは、σ＝０．１μｍ）となり、ほぼ均一な膜厚に形成されていることが確認できた。
【００５７】
次に、図３（ａ）、（ｂ）のような被覆樹脂層４を形成するために、下表３の被覆樹脂組成物を、塗布溶媒としての２−エトキシエタノールに５０ｗｔ％の濃度で溶解し、それをスピンコートによりインク流路パターン３上に塗布した。その塗布は、被覆樹脂層４が１２μｍとなるように、スピン回転数を調整しながら行う。その後、９０℃の温度で３分間ベークして、塗布溶媒の乾燥を行った。
【００５８】
【表３】

【００５９】
次に、図４（ａ）および（ｂ）のように吐出口５を形成する。本例の場合、被覆樹脂層４は、光カチオン重合開始剤を含み、ネガ型の感光特性が付与されているため、フォトリソグラフィーによって吐出口５を形成する。すなわち、キャノン製マスクアライナーＰＬＡ６２０を用い、マスクを介してパターン露光（露光時間４秒）を行い、次いで９０℃の温度で３分間加熱処理を行った後に、現像処置を施して吐出口５を形成した。吐出口５の径は、φ２０μｍに形成した。
【００６０】
次に、シリコン基板１の裏面から、マスクを介して、シリコンの異方性エッチングを行い、図５（ａ）および（ｂ）のようなインク供給口６を形成した。次に、現工程において残存しているインク流路パターンを全面露光により分解した後、図６（ａ）および（ｂ）のように、それを乳酸メチルによって除去した。その後、被覆樹脂層４を完全に硬化させるために、２００℃の温度で１時間の加熱処理をした。
【００６１】
このようにしてノズル構造を成した後、干渉膜厚計（Ｚｙｇｏ　ｎｅｗ　ｖｉｅｗ　２００）を用いて、電気熱変換素子２と吐出口５の形成面との間のＯＨ距離を測定した。そのＯＨ距離の測定個所は、１つの基板（１チップ）１内の１０ノズルを１０個の基板分（１０チップ分）、つまり計１００ノズル分とした。その１００ノズル分のＯＨ距離の平均は、２５．０μｍ（バラツキは。σ＝０．０４μｍ）であった。
【００６２】
このような本実施例のノズル構造の比較対象として、被覆樹脂の塗布溶媒として、２−エトキシエタノールに代えて、前述した特開平６−２８６１４９号公報の実施例１に記載されているメチルイソブチルケトン／キシレン＝１／１（重量部）を用いて、被覆樹脂層４を形成した。その比較対象のサンプルのＯＨ距離を前述した測定方法により測定した結果、その平均が２４．９μｍ（バラツキは、σ＝０．９μｍ）であった。上述した本発明の実施例におけるＯＨ距離の平均値と、その比較対象のサンプルにおけるＯＨ距離の平均値は、両者共に、ほぼ設計値の２５μｍに形成されてはいるものの、ＯＨ距離のバラツキσの値は、後者の比較対象のサンプルに比して、前者の本発明の実施例の場合の方が半分以下に低減していることが確認できた。
【００６３】
さらに、前者の本発明の実施例におけるノズル構造と、後者の比較対象のサンプルにおけるノズル構造のぞれぞれに対して、電気的接続およびインクタンク供給部材を配置して記録ヘッドを構成して、それらの両者の記録ヘッドからインク滴を吐出した。そして、両者の記録ヘッドのそれぞれに対して、１つの記録ヘッド当たり１ノズルからのインク滴の吐出量を１０個の記録ヘッド分測定した結果、前者の本発明の実施例の記録ヘッドにおけるインク滴の吐出量の平均値は８．５ピコリットル、バラツキは±０．３ピコリットルであった。一方、後者の比較対象のサンプルにおけるインク滴の吐出量の平均値は８．５ピコリットル、バラツキは±０．６ピコリットルであった。これら両者の比較から明らかなように、本発明の実施例のように塗布溶媒として２−エトキシエタノール（エチルセルソルブ）を用いた記録ヘッドは、ＯＨ精度のバラツキの低減を反映して、インク滴の吐出量のバラツキを小さく抑えることができる。
【００６４】
（第２の実施形態の実施例２）
本実施例では、前述した図１から図６に示される手順にしたがって、インクジェット記録ヘッドを製作した。まず、シリコン基板１上に、図１に示すような形態で、２４μｍ角の電気熱変換素子（窒化タンタル　ＴａＮ）２を２列配した。
電気熱変換素子２は３００ノズル分配置され、その配備形態は、６００ＤＰＩのピッチで２列、かつ千鳥状に配されており、記録ヘッドとして１２００ＤＰＩの３００ノズルが形成できるようになっている。なお、基板１は、シリコン基板用素材に２５０チップ分配列される。
【００６５】
次に、上述した実施例１と同様にして、図２（ａ）および（ｂ）のような溶解可能な樹脂によってインク流路パターン３を形成した。そのインク流路パターン３の設計形状は、図８（図１のＢ―Ｂ′線に沿う断面図に相当）のとおりであり、幅が３０μｍ、膜厚が１３μｍである。また、電気熱変換素子２の幅は２４μｍ、隣接する電気熱変換素子２の間隔は４２．５μｍである。
【００６６】
１つの基板（１チップ）１内の１０ノズルのインク流路パターン３の膜厚を１０個の基板分（１０チップ分）、つまり計１００ノズル分のインク流路パターン３の膜厚を膜厚計（λエース）によって測定した結果、その膜厚平均が１３．０μｍ（バラツキは、σ＝０．１μｍ）となり、ほぼ均一な膜厚に形成されていることが確認できた。
【００６７】
次に、図３（ａ）、（ｂ）のような被覆樹脂層４を形成するために、下表４の被覆樹脂組成物を、塗布溶媒としての２−エトキシエタノールに５０ｗｔ％の濃度で溶解し、それをスピンコートによりインク流路パターン３上に塗布した。その塗布は、被覆樹脂層４が１２μｍとなるように、スピン回転数を調整しながら行う。その後、９０℃の温度で３分間ベークして、塗布溶媒の乾燥を行った。
【００６８】
【表４】

【００６９】
次に、図４（ａ）および（ｂ）のように吐出口５を形成する。本例の場合、被覆樹脂層４は、光カチオン重合開始剤を含み、ネガ型の感光特性が付与されているため、フォトリソグラフィーによって吐出口５を形成する。すなわち、キャノン製マスクアライナーＭＰＡ６００を用い、マスクを介してパターン露光（露光時間６０秒）を行い、次いで９０℃の温度で３分間加熱処理を行った後に、現像処置を施して吐出口５を形成した。吐出口５の径は、φ１５μｍに形成した。
【００７０】
次に、シリコン基板１の裏面から、マスクを介して、シリコンの異方性エッチングを行い、図５（ａ）および（ｂ）のようなインク供給口６を形成した。次に、現工程において残存しているインク流路パターンを全面露光により分解した後、図６（ａ）および（ｂ）のように、それを乳酸メチルによって除去した。その後、被覆樹脂層４を完全に硬化させるために、２００℃の温度で１時間の加熱処理をした。
【００７１】
このようにしてノズル構造を成した後、干渉膜厚計（Ｚｙｇｏ　ｎｅｗ　ｖｉｅｗ　２００）を用いて、電気熱変換素子２と吐出口５の形成面との間のＯＨ距離を測定した。そのＯＨ距離の測定個所は、１つの基板（１チップ）１内の１０ノズルを１０個の基板分（１０チップ分）、つまり計１００ノズル分とした。その１００ノズル分のＯＨ距離の平均は、２５．０μｍ（バラツキは、σ＝０．３μｍ）であった。
【００７２】
さらに、このようなノズル構造に対して、電気的接続およびインクタンク供給部材を配置して記録ヘッドを構成して、その記録ヘッドからインク滴を吐出した。そして、１つの記録ヘッド当たり１ノズルからのインク滴の吐出量を１０個の記録ヘッド分測定した結果、インク滴の吐出量の平均値は５．０ピコリットル、バラツキは±０．２ピコリットルであった。このように１ノズル当たりのインク吐出量が５ピコリットルの微小量であるにも拘わらず、そのバラツキをきわめて小さい範囲に抑えることができた。
【００７３】
以上の実施例１，２において、前述した本発明の第１の実施形態と同様に、被覆樹脂層４の塗布終了後に減圧下に保持することにより、薄膜状のゴミの出現率を抑えて、記録ヘッドの製造上の歩留まりを向上させることもできる。これらの組合せの相乗効果により、記録ヘッドの信頼性を大幅に向上させることができる。
【００７４】
（インクジェット記録ヘッド全体の構成例）
図９は、本発明のインクジェット記録ヘッドの全体的な構成例を説明するための斜視図である。
【００７５】
図９において、２は、前述した第１、第２の実施形態におけるノズル構造を成す素子基板であり、２列に配列された複数の吐出口４が千鳥状に設けられている。素子基板２は、Ｌ字状に加工された支持部材１０２の一部に接着固定されている。この支持部材１０２上に固定された配線基板１０４の配線部分と、素子基板２における配線部分は、ボンディングにより電気的に接続されている。支持部材１０２は、コストおよび加工性等の観点から、アルミニウム材によって形成される。モールド部材１０３は、その内部に支持部材１０２の一部を挿入して、その支持部材１０２を支持すると共に、その内部に形成されたインク供給路を介して、インク貯留部から、前述したインク供給口６にインクを供給するための部材である。また、モールド部材１０３は、本例の記録ヘッド全体をインクジェット記録装置に着脱自在に固定するための装着、位置決め部材としての役割を果たす。
【００７６】
（インクジェット記録装置の構成例）
図１０は、本発明のインクジェット記録ヘッドを使用可能なシリアルタイプのインクジェット記録装置の概略斜視図である。
【００７７】
図１０において、２００は、上述した本発明のインクジェット記録ヘッドが着脱自在に装着されるキャリッジである。本例の場合、記録ヘッドは、インク色の種類に応じて４種類装着され、イエローインクのタンク２０１Ｙ、マゼンタインクのタンク２０１Ｍ、シアンインクのタンク２０１Ｃ、ブラックインクのタンク２０１Ｂと共に、キャリッジ２００上に搭載される。
【００７８】
キャリッジ２００は、ガイドシャフト２０２に支持され、モータ２０３により順方向または逆方向に駆動される無端ベルト２０４により、ガイドシャフト２０２に沿って矢印Ａ方向（主走査方向）に往復移動される。無端ベルト２０４は、プーリ２０５，２０６間に架け渡されている。
【００７９】
被記録媒体としての記録紙Ｐは、矢印Ａ方向と直交する矢印Ｂ方向（副走査方向）に間欠的に搬送される。記録紙Ｐは、上流側の一対のローラユニット２０７，２０８と、下流側の一対のローラユニット２０９，２１０とによって挟持され、かつ一定の張力が印加されて、記録ヘッドに対する平面性を確保しながら搬送される。各ローラユニットに対する駆動力は、駆動部２１１から付与される。また、各ローラユニットは、モータ２０３によって駆動する構成としてもよい。
【００８０】
キャリッジ２００は、記録開始または記録動作中に、必要に応じてホームポジッションに停止する。このポジッションには、各記録ヘッドの吐出口面をキャップするキャップ部材２１２が設けられている。キャップ部材２１２には、吐出口面に開口する吐出口から画像の記録に寄与しないインクを強制的に吸引して、吐出口内の目詰まりを防止するための吸引回復手段が接続されている。
【００８１】
（その他）
なお、本発明は、特にインクジェット記録方式の中でも、インク吐出を行わせるために利用されるエネルギとして熱エネルギを発生する手段（例えば電気熱変換体やレーザ光等）を備え、前記熱エネルギによりインクの状態変化を生起させる方式の記録ヘッド、記録装置において優れた効果をもたらすものである。かかる方式によれば記録の高密度化，高精細化が達成できるからである。
【００８２】
その代表的な構成や原理については、例えば、米国特許第４７２３１２９号明細書，同第４７４０７９６号明細書に開示されている基本的な原理を用いて行うものが好ましい。この方式は所謂オンデマンド型，コンティニュアス型のいずれにも適用可能であるが、特に、オンデマンド型の場合には、液体（インク）が保持されているシートや液路に対応して配置されている電気熱変換体に、記録情報に対応していて核沸騰を越える急速な温度上昇を与える少なくとも１つの駆動信号を印加することによって、電気熱変換体に熱エネルギを発生せしめ、記録ヘッドの熱作用面に膜沸騰を生じさせて、結果的にこの駆動信号に一対一で対応した液体（インク）内の気泡を形成できるので有効である。この気泡の成長，収縮により吐出用開口を介して液体（インク）を吐出させて、少なくとも１つの滴を形成する。この駆動信号をパルス形状とすると、即時適切に気泡の成長収縮が行われるので、特に応答性に優れた液体（インク）の吐出が達成でき、より好ましい。このパルス形状の駆動信号としては、米国特許第４４６３３５９号明細書，同第４３４５２６２号明細書に記載されているようなものが適している。なお、上記熱作用面の温度上昇率に関する発明の米国特許第４３１３１２４号明細書に記載されている条件を採用すると、さらに優れた記録を行うことができる。
【００８３】
記録ヘッドの構成としては、上述の各明細書に開示されているような吐出口，液路，電気熱変換体の組合せ構成（直線状液流路または直角液流路）の他に熱作用部が屈曲する領域に配置されている構成を開示する米国特許第４５５８３３３号明細書，米国特許第４４５９６００号明細書を用いた構成も本発明に含まれるものである。加えて、複数の電気熱変換体に対して、共通するスリットを電気熱変換体の吐出部とする構成を開示する特開昭５９−１２３６７０号公報や熱エネルギの圧力波を吸収する開孔を吐出部に対応させる構成を開示する特開昭５９−１３８４６１号公報に基いた構成としても本発明の効果は有効である。すなわち、記録ヘッドの形態がどのようなものであっても、本発明によれば記録を確実に効率よく行うことができるようになるからである。
【００８４】
さらに、記録装置が記録できる記録媒体の最大幅に対応した長さを有するフルラインタイプの記録ヘッドに対しても本発明は有効に適用できる。そのような記録ヘッドとしては、複数記録ヘッドの組合せによってその長さを満たす構成や、一体的に形成された１個の記録ヘッドとしての構成のいずれでもよい。
【００８５】
加えて、上例のようなシリアルタイプのものでも、装置本体に固定された記録ヘッド、あるいは装置本体に装着されることで装置本体との電気的な接続や装置本体からのインクの供給が可能になる交換自在のチップタイプの記録ヘッド、あるいは記録ヘッド自体に一体的にインクタンクが設けられたカートリッジタイプの記録ヘッドを用いた場合にも本発明は有効である。
【００８６】
また、本発明の記録装置の構成として、記録ヘッドの吐出回復手段、予備的な補助手段等を付加することは本発明の効果を一層安定できるので、好ましいものである。これらを具体的に挙げれば、記録ヘッドに対してのキャッピング手段、クリーニング手段、加圧或は吸引手段、電気熱変換体或はこれとは別の加熱素子或はこれらの組み合わせを用いて加熱を行う予備加熱手段、記録とは別の吐出を行なう予備吐出手段を挙げることができる。
【００８７】
また、搭載される記録ヘッドの種類ないし個数についても、例えば単色のインクに対応して１個のみが設けられたものの他、記録色や濃度を異にする複数のインクに対応して複数個数設けられるものであってもよい。すなわち、例えば記録装置の記録モードとしては黒色等の主流色のみの記録モードだけではなく、記録ヘッドを一体的に構成するか複数個の組み合わせによるかいずれでもよいが、異なる色の複色カラー、または混色によるフルカラーの各記録モードの少なくとも一つを備えた装置にも本発明は極めて有効である。
【００８８】
さらに加えて、以上説明した本発明実施例においては、インクを液体として説明しているが、室温やそれ以下で固化するインクであって、室温で軟化もしくは液化するものを用いてもよく、あるいはインクジェット方式ではインク自体を３０℃以上７０℃以下の範囲内で温度調整を行ってインクの粘性を安定吐出範囲にあるように温度制御するものが一般的であるから、使用記録信号付与時にインクが液状をなすものを用いてもよい。加えて、熱エネルギによる昇温を、インクの固形状態から液体状態への状態変化のエネルギとして使用せしめることで積極的に防止するため、またはインクの蒸発を防止するため、放置状態で固化し加熱によって液化するインクを用いてもよい。いずれにしても熱エネルギの記録信号に応じた付与によってインクが液化し、液状インクが吐出されるものや、記録媒体に到達する時点ではすでに固化し始めるもの等のような、熱エネルギの付与によって初めて液化する性質のインクを使用する場合も本発明は適用可能である。このような場合のインクは、特開昭５４−５６８４７号公報あるいは特開昭６０−７１２６０号公報に記載されるような、多孔質シート凹部または貫通孔に液状又は固形物として保持された状態で、電気熱変換体に対して対向するような形態としてもよい。本発明においては、上述した各インクに対して最も有効なものは、上述した膜沸騰方式を実行するものである。
【００８９】
さらに加えて、本発明インクジェット記録装置の形態としては、コンピュータ等の情報処理機器の画像出力端末として用いられるものの他、リーダ等と組合せた複写装置、さらには送受信機能を有するファクシミリ装置の形態を採るもの等であってもよい。
【００９０】
【発明の効果】
以上説明したように、本発明は、溶解可能な樹脂によって形成された基体上のインク流路パターンの上に、インク流路壁となる被覆樹脂層を形成するソルベントコート後に、その被覆樹脂層を減圧状態に保持することによって、その被覆樹脂層を形成する被覆樹脂の溶媒の除去を促進し、インク流路パターンと被覆樹脂層との間に、記録ヘッドの最終製造工程においてゴミとなる相溶層が発生することを回避して、インクジェット記録ヘッドの製造上の歩留まりを向上させることができる。
【００９１】
さらに、被覆樹脂層を形成する被覆樹脂の溶媒として、２−エトキシエタノールを含む溶媒を用いることにより、被覆樹脂層の表面の平坦度を向上させて、インク吐出量のバラツキをきわめて小さい範囲に抑えることができる。
【図面の簡単な説明】
【図１】本発明の記録ヘッドを構成する基板の斜視図である。
【図２】（ａ）は、本発明の記録ヘッドのインク流路パターン形成段階における図１のＡ―Ａ′線に沿う断面図、（ｂ）は、そのインク流路パターンの形成段階における図１のＢ−Ｂ′線に沿う断面図である。
【図３】（ａ）は、本発明の記録ヘッドの被覆樹脂層形成段階における図１のＡ―Ａ′線に沿う断面図、（ｂ）は、その被覆樹脂層形成段階における図１のＢ−Ｂ′線に沿う断面図である。
【図４】（ａ）は、本発明の記録ヘッドの吐出口形成段階における図１のＡ―Ａ′線に沿う断面図、（ｂ）は、その吐出口形成段階における図１のＢ−Ｂ′線に沿う断面図である。
【図５】（ａ）は、本発明の記録ヘッドのインク供給口形成段階における図１のＡ―Ａ′線に沿う断面図、（ｂ）は、そのインク供給口形成段階における図１のＢ−Ｂ′線に沿う断面図である。
【図６】（ａ）は、本発明の記録ヘッドの被覆樹脂層溶解段階における図１のＡ―Ａ′線に沿う断面図、（ｂ）は、その被覆樹脂層溶解段階における図１のＢ−Ｂ′線に沿う断面図である。
【図７】本発明の記録ヘッドの第２の実施形態における実施例１の要部の拡大断面図である。
【図８】本発明の記録ヘッドの第２の実施形態における実施例２の要部の拡大断面図である。
【図９】本発明の記録ヘッド全体の構成例を説明するための斜視図である。
【図１０】本発明の記録ヘッドを使用可能な記録装置の要部の斜視図である。
【符号の説明】
１　基板（基体）
２　電気熱変換素子
３　インク流路パターン
４　被覆樹脂層
５　吐出口
６　インク供給口[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an ink jet recording head capable of discharging fine ink droplets, an ink jet recording head manufactured by the method, and an ink jet recording apparatus using the ink jet recording head manufactured by the method.
[0002]
[Prior art]
Conventionally, various methods have been proposed for a method of manufacturing an ink jet recording head used in an ink jet recording technique. The present applicant has previously proposed in Patent Document 1 a method of manufacturing an inkjet recording head that is optimal for obtaining a high-quality image. Patent Document 1 describes a method of manufacturing an ink jet recording head that is optimal for the following ink discharging method. That is, the ink ejection method includes a method of driving a driving signal corresponding to recording information to an electrothermal conversion element as an ink ejection pressure generating element (ejection energy generating element) described in Patent Document 2, Patent Document 3, and Patent Document 4. By applying heat to the electrothermal conversion element to generate thermal energy that gives the ink a sharp temperature rise exceeding the nucleate boiling, thereby forming bubbles in the ink, and communicating the bubbles with the outside air to form ink droplets. Is a method of discharging the ink. Specifically, Patent Literature 1 discloses a method of forming a coating resin layer containing an epoxy resin on a dissolvable ink flow path pattern.
[0003]
Further, in the ink discharging methods described in Patent Documents 2, 3, and 4, the distance between the electrothermal transducer and the orifice (the surface on which the ink discharge port is formed) (hereinafter referred to as “OH” distance). ) Is the main factor in determining the ink ejection volume, so it is important to set the OH distance accurately with respect to the design value and with good reproducibility. As a specific example, Patent Document 1 proposed by the present applicant discloses that, when a coating resin layer containing an epoxy resin is formed on an ink flow path pattern formed of a dissolvable resin, the coating resin is applied. A method is disclosed in which a solvent is dissolved in a solvent at a concentration of 30 to 70% by weight, and the solution is solvent-coated.
[0004]
[Patent Document 1]
JP-A-6-286149
[0005]
[Patent Document 2]
JP-A-4-10940
[0006]
[Patent Document 3]
JP-A-4-10941
[0007]
[Patent Document 4]
JP-A-4-10942
[0008]
[Problems to be solved by the invention]
According to a detailed study by the present inventors, when forming a coating resin layer containing an epoxy resin on an ink flow path pattern formed of a dissolvable resin, in rare cases, the ink flow path pattern and the coating resin layer It was confirmed that a very thin compatible layer was generated between them, and this became dust in the final step, resulting in the occurrence of defective products.
[0009]
Further, as a method for preventing compatibility between resists when laminating resists, for example, JP-A-5-17285 discloses that an upper resist is formed by vapor deposition polymerization. However, in the inkjet recording head, the coating resin layer needs to have a thickness of about 5 μm or more, and it is required to form a film with good coverage on the ink flow path pattern. Have difficulty.
[0010]
On the other hand, in recent years, there has been a demand for high image quality comparable to silver halide photography in ink jet recording, and for that purpose, it is necessary to eject ink droplets of about 10 picoliters or less with good reproducibility. It is becoming necessary to further improve the nozzle structure including the OH distance setting accuracy described above.
[0011]
An object of the present invention is to improve the production yield of an ink jet recording head, further improve the flatness of the surface of a coating resin layer, and suppress the variation in ink ejection amount to a very small range. An object of the present invention is to provide a manufacturing method, an inkjet recording head, and an inkjet recording device.
[0012]
[Means for Solving the Problems]
The method of manufacturing an ink jet recording head according to the present invention includes: (1) a step of forming an ink flow path pattern with a dissolvable resin on a substrate provided with a discharge energy generating element for generating discharge energy of ink; ▼ By dissolving a coating resin containing a solid epoxy resin at room temperature in a solvent, and solvent-coating this on a dissolvable resin layer forming the ink flow path pattern, the dissolvable resin layer A step of forming a coating resin layer serving as an ink flow path wall thereon; (3) a step of forming an ink discharge port at a position of the coating resin layer located above the discharge energy generating element; A step of eluting the dissolvable resin layer, and a method of manufacturing an ink jet recording head, comprising: after solvent coating for forming the coating resin layer, The serial coating resin layer, characterized in that it comprises a step of maintaining a reduced pressure state.
[0013]
An inkjet recording head according to the present invention is manufactured by the above method.
[0014]
An inkjet recording apparatus of the present invention is an inkjet recording apparatus capable of recording an image on a recording medium using an inkjet recording head, wherein the inkjet recording head manufactured by the above method is used as the inkjet recording head. And
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
(1st Embodiment)
FIG. 1 is a perspective view of a silicon substrate 1 on which a plurality of electrothermal conversion elements 2 as ink discharge pressure generating elements (discharge energy generating elements) are arranged. Electrodes and IC circuits (not shown) are connected to the electrothermal conversion element 2 to operate the element 2.
[0017]
2 to 6 are explanatory diagrams of a procedure for manufacturing an ink jet recording head using the silicon substrate 1 of FIG. In these figures, (a) is a cross-sectional view along the line AA in FIG. 1, and (b) is a cross-sectional view along the line BB in FIG.
[0018]
First, as shown in FIGS. 2A and 2B, an ink flow path pattern 3 is formed on a substrate 1 using a soluble resin layer. As a material for forming the ink flow path pattern, a positive resist can be suitably used. The positive resist is required to have a property of not dissolving when the coating resin layer described below is solvent-coated, and therefore a resist composed of an ionizing radiation decomposable polymer compound having a molecular weight of 10,000 or more is optimal. Specific examples include polymethyl methacrylate and polymethyl isopropenyl ketone.
[0019]
Next, a coating resin containing an epoxy resin is dissolved in a solvent, and the solution is applied onto the dissolvable ink flow path pattern 3 by a solvent coating method such as spin coating, and is then applied to the ink flow path pattern 3 shown in FIGS. Such a coating resin layer 4 is formed.
[0020]
Usually, in a solvent coating method such as spin coating, a coating solvent is dried by heat treatment (approximately 70 ° C. to 120 ° C.) after coating to form a film. That is, a heat treatment for drying the solvent is performed in a state where the application solvent at the end of the application is considerably remaining. Therefore, an extremely thin compatible layer may be formed between the ink flow path pattern and the coating resin layer 4. According to the study of the present inventor, it has been found that this compatible layer remains as dust in the post-processing step, and as a result, it is one of the causes of lowering the production yield of the inkjet recording head.
[0021]
When forming the coating resin layer 4 on the dissolvable ink flow path pattern 3, the inventor holds the substrate 1 in a reduced pressure state after the application of the dissolved coating resin and before the heat treatment. It has been found that the generation of the above-mentioned compatible layer can be completely suppressed by removing most of the coating solvent and then performing heat treatment to form a film. Therefore, when forming the coating resin layer 4 in FIGS. 3A and 3B, the application solvent was removed by such reduced pressure. The reduced pressure state can be appropriately set according to the vapor pressure of the coating solvent used. The reduced pressure state needs to be set to approximately 50 cmHg or less, and is preferably set to 30 cmHg or less. Further, the temperature of the substrate 1 under such reduced pressure is preferably set to 50 ° C. or lower. That is, from the viewpoint of drying the solvent, it is preferable that the temperature is high even in the reduced pressure state, but from the viewpoint of preventing the formation of the compatible layer, the temperature is preferably 50 ° C. or less.
[0022]
The coating solvent needs to have a property of completely dissolving the epoxy resin or the like and not dissolving the ink flow path pattern 3 and is appropriately selected depending on the thickness of the coating resin layer 4 to be formed. Specific examples include methyl isobutyl ketone, 2 ethoxyethanol, ethyl cellosolve acetate, diglyme, toluene, xylene and the like.
[0023]
After the formation of the coating resin layer 4, the discharge ports 5 are formed in the coating resin layer 4 as shown in FIGS. 4 (a) and 4 (b). As a method for forming the discharge port 5, for example, a method in which the coating resin layer 4 is provided with photosensitivity and exposed (light-cured) by ordinary photolithography technology and developed, or the coating resin layer 4 is formed. May be cured by heating and then formed by etching with an excimer laser or oxygen plasma.
[0024]
Next, as shown in FIGS. 5A and 5B, the substrate 1 is subjected to anisotropic etching from the back surface to form an ink supply port 6. The ink supply port 6 may be formed in the substrate 1 in advance by mechanical processing.
[0025]
Finally, as shown in FIGS. 6A and 6B, the ink flow path pattern 3 is dissolved to complete the nozzle. Then, an ink jet recording head is completed by electrical connection (not shown) and connection with an ink supply member.
[0026]
Hereinafter, a specific example of the first embodiment of the present invention will be described.
[0027]
(Example 1 of the first embodiment)
In this embodiment, an ink jet recording head was manufactured according to the procedure shown in FIGS. First, two rows of 30 μm square electrothermal conversion elements (tantalum nitride TaN) 2 were arranged on a silicon substrate 1 in a form as shown in FIG.
The electrothermal conversion elements 2 are arranged for 256 nozzles, and are arranged in two rows at a pitch of 300 DPI in a staggered manner, so that 256 nozzles of 600 DPI can be formed as a recording head. The substrate 1 is arranged in a silicon substrate material for 200 chips.
[0028]
Next, in order to form the ink flow path pattern 3 with a dissolvable resin as shown in FIGS. 2A and 2B, a positive resist ODUR1010 (polymethylisopropenyl ketone manufactured by Tokyo Ohka Kogyo Co., Ltd.) is spin-coated. To form a film. After that, pattern exposure (exposure time: 3 minutes) was performed through a mask using a mask aligner PLA620 (compatible with deep UV) manufactured by Canon Inc., and then development was performed to form an ink flow path pattern 3.
[0029]
Next, in order to form the coating resin layer 4 as shown in FIGS. 3A and 3B, the coating resin composition shown in Table 1 below was dissolved at a concentration of 50 wt% in 2-ethoxyethanol as a coating solvent. Then, it was applied on the ink flow path pattern 3 by spin coating. The application is performed while adjusting the spin rotation speed so that the coating resin layer 4 has a thickness of 12 μm. After completion of the spin coating, the coating was held at a temperature of 40 ° C. for 3 minutes under a reduced pressure of 5 cmHg, and finally baked at a temperature of 90 ° C. for 3 minutes under normal pressure to dry the coating solvent.
[0030]
[Table 1]

[0031]
Next, the discharge port 5 is formed as shown in FIGS. In the case of this example, since the coating resin layer 4 contains a photocationic polymerization initiator and has negative photosensitive characteristics, the discharge ports 5 are formed by photolithography. That is, using a mask aligner MPA600 manufactured by Canon, pattern exposure (exposure time: 50 seconds) is performed through a mask, and then heat treatment is performed at a temperature of 90 ° C. for 4 minutes, and then development processing is performed to form the discharge port 5. did. The diameter of the discharge port 5 was formed to be φ20 μm.
[0032]
Next, anisotropic etching of silicon was performed from the back surface of the silicon substrate 1 via a mask to form an ink supply port 6 as shown in FIGS. 5A and 5B.
[0033]
Next, after the ink flow path pattern 3 remaining in the present process was decomposed by whole-surface exposure, as shown in FIGS. 6A and 6B, it was removed with methyl lactate.
[0034]
Thereafter, in order to completely cure the coating resin layer 4, a heat treatment was performed at a temperature of 200 ° C. for 1 hour, and then an electrical connection and an ink supply member were arranged, thereby completing an ink jet recording head.
[0035]
As a comparative object of the recording head of this embodiment manufactured in this way, after the spin coating of the coating resin layer 4 is completed, the coating resin layer 4 is baked at a temperature of 90 ° C. under normal pressure for 3 minutes without being kept under reduced pressure. Thus, a sample in which the coating solvent was dried was prepared. The processing for the sample is the same as the processing for the recording head of the above-described embodiment, except that there is no holding under reduced pressure after the completion of the spin coating of the coating resin layer 4.
[0036]
In the case of the recording head of this embodiment, that is, the recording head held under reduced pressure after the completion of the spin coating of the coating resin layer 4, the yield was 95% as a result of the recording inspection for recording an image of a predetermined pattern. When analysis was performed for 5% of the defects, no dust or the like was detected by microscopic observation, and the cause could not be specified.
[0037]
On the other hand, in the case of the sample to be compared, that is, the recording head which was not kept under reduced pressure after the completion of the spin coating of the coating resin layer 4, the yield was 81% as a result of the recording inspection similar to that of the recording head of this embodiment. Was. An analysis was performed on 19% of the defects. Microscopic observation revealed that 13% of the defects were caused by thin film-like dust, and 6% were that the cause could not be identified without detecting dust or the like. The thin film dust is considered to be a compatible substance of the ink flow path pattern 3 and the coating resin layer 4.
[0038]
(Example 2 of the first embodiment)
In this embodiment, two rows of 24 μm square electrothermal transducers 2 are arranged. The electrothermal transducers 2 are arranged for 300 nozzles, and are arranged in a staggered manner in two rows at a pitch of 600 DPI, so that 300 nozzles of 1200 DPI can be formed as a recording head. The substrate 1 is arranged on a silicon substrate material for 250 chips.
[0039]
Using such a substrate 1, a recording head was prepared in the same manner as in Example 1 described above. However, the coating resin composition of Table 1 described above was dissolved at a concentration of 45 wt% using xylene as a coating solvent, and was applied onto the ink flow path pattern 3 by spin coating. The application is performed while adjusting the spin rotation speed so that the coating resin layer 4 has a thickness of 12 μm. After completion of the spin coating, the coating was held at a temperature of 40 ° C. for 3 minutes under a reduced pressure of 10 cmHg, and finally baked at a temperature of 90 ° C. under a normal pressure for 3 minutes to dry the coating solvent. The diameter of the discharge port 5 was 15 μm.
[0040]
As a comparative object of the recording head of the present embodiment manufactured in this way, after completion of the spin coating of the coating resin layer 4, without baking under reduced pressure, baking at a temperature of 90 ° C. under normal pressure for 3 minutes. A sample in which the coating solvent was dried was prepared.
[0041]
In the case of the recording head of this example, that is, the recording head held under reduced pressure after the completion of the spin coating of the coating resin layer 4, the yield was 93% as a result of the recording inspection for recording an image of a predetermined pattern. When analysis was performed for 7% of the defects, thread-like dust and the like were detected in 2% of the recording heads by microscopic observation, and dust and the like were not detected in the remaining recording heads, and the cause could not be identified. The thread-like dust was considered to have been mixed during the assembling process, and was clearly different in form from the thin-film dust detected in the sample as a comparative example of Example 1 described above.
[0042]
On the other hand, in the case of the sample to be compared, that is, the recording head which was not kept under reduced pressure after the completion of the spin coating of the coating resin layer 4, the yield was 85% as a result of the recording inspection similar to that of the recording head of this embodiment. Was. When 15% of the defects were analyzed, microscopic observation revealed that 10% of the defects were caused by thin-film-like dust, and 5% were that no dust or the like was detected and the cause could not be identified. The thin film dust is considered to be a compatible substance of the ink flow path pattern 3 and the coating resin layer 4.
[0043]
(Example 3 of the first embodiment)
In this embodiment, a recording head was prepared in the same manner as in the first embodiment. However, methylisobutylketone / diglyme = 1/1 (wt) was used as a coating solvent, the coating resin composition shown in Table 2 below was dissolved at a concentration of 50 wt%, and the solution was applied onto the ink flow path pattern 3 by spin coating. Applied. The application is performed while adjusting the spin rotation speed so that the coating resin layer 4 has a thickness of 12 μm. After completion of the spin coating, the coating was held at a temperature of 40 ° C. for 3 minutes under a reduced pressure of 5 cmHg, and finally baked at a temperature of 90 ° C. for 3 minutes under normal pressure to dry the coating solvent. Note that the diameter of the discharge port 5 was φ20 μm. In forming the discharge port 5, the exposure time was set to 60 seconds.
[0044]
[Table 2]

[0045]
As a comparative object of the recording head of the present embodiment manufactured in this way, after completion of the spin coating of the coating resin layer 4, without baking under reduced pressure, baking at a temperature of 90 ° C. under normal pressure for 3 minutes. A sample in which the coating solvent was dried was prepared.
[0046]
In the case of the recording head of this example, that is, the recording head held under reduced pressure after the completion of the spin coating of the coating resin layer 4, the yield was 82% as a result of the recording inspection for recording an image of a predetermined pattern. When analysis was performed on 18% of the defects, thin film dust and the like were not detected by microscopic observation.
[0047]
On the other hand, in the case of the sample to be compared, that is, the recording head which was not kept under reduced pressure after the completion of the spin coating of the coating resin layer 4, the yield was 75% as a result of the recording inspection similar to the recording head of the present embodiment. Was. When analysis was performed on 25% of the defects, 18% of defects due to thin film dust were detected by microscopic observation. The thin film dust is considered to be a compatible substance of the ink flow path pattern 3 and the coating resin layer 4.
[0048]
As is clear from the above Examples 1, 2 and 3, irrespective of the type of the coating solvent, the recording head was kept under reduced pressure after the completion of the spin coating of the coating resin layer 4 and after the spin coating of the coating resin layer 4 was completed. As a result of the recording inspection of the recording head that was not held under reduced pressure, a large difference occurred in the appearance rate of thin film dust considered to be a compatible substance between the ink flow path pattern 3 and the coating resin layer 4, resulting in a difference in yield. occured.
[0049]
(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described.
[0050]
In the present embodiment, similarly to the above-described first embodiment, a print head is manufactured by the same procedure as in FIGS. In the embodiment, the coating resin containing the epoxy resin is dissolved in a solvent at the manufacturing stage of FIGS. 3A and 3B, and the solution is coated on the ink flow path pattern 3 by a solvent coating method such as spin coating. In the manufacturing step of forming the coating resin layer 4 by coating, the coating solvent was selected from the viewpoint of the accuracy of the film thickness of the coating resin layer 4.
[0051]
That is, first, since the ink flow path pattern 3 has a film thickness of 10 μm or more in many cases, the coating resin layer 4 must be formed so as to absorb at least irregularities of 10 μm or more and have a flat surface. Must. 3A and 3B, the total distance L of the film thickness of the ink flow path pattern 3 on the electrothermal transducer 2 and the film thickness of the coating resin layer 4 is the above-mentioned OH distance, that is, the electric distance. It is the distance between the heat conversion element 2 and the orifice (the surface on which the ink discharge port is formed). As described above, it is important to accurately set the OH distance in suppressing the variation in the characteristics of each nozzle. . Regarding the former method of controlling the film thickness of the ink flow path pattern 3, since the ink flow path pattern 3 is basically formed on the substantially flat substrate 1, sufficient film thickness accuracy can be obtained by a normal spin coating method or the like. it can. The problem is the latter film thickness control of the coating resin layer 4.
[0052]
The above-mentioned Japanese Patent Application Laid-Open No. 6-286149 discloses that when a coating resin layer 4 containing an epoxy resin is formed on an ink flow path pattern 3 formed of a dissolvable resin, the concentration of the coating resin is 30 to 70 wt%. Discloses a method of dissolving in a coating solvent and forming it by a solvent coat. As a result of detailed studies by the present inventor, it became clear that in order to control the film thickness of the coating resin layer 4 with higher accuracy, it is necessary to select a coating solvent in addition to the solid content concentration of the coating resin. In selecting a coating solvent, consideration must be given to the thickness of the thick film, such as dissolving and deforming the dissolvable flow path pattern 3 and dissolving the coating resin including the epoxy resin to a required solid content concentration. There are other considerations. According to the study of the present inventors, it has been found that 2-ethoxyethanol (trade name: ethylcellosolve) is optimal as a coating solvent.
[0053]
Hereinafter, a specific example of the second embodiment of the present invention will be described.
[0054]
(Example 1 of the second embodiment)
In this embodiment, an ink jet recording head was manufactured according to the procedure shown in FIGS. First, two rows of 30 μm square electrothermal conversion elements (tantalum nitride TaN) 2 were arranged on a silicon substrate 1 in a form as shown in FIG. The electrothermal conversion elements 2 are arranged for 256 nozzles, and are arranged in two rows at a pitch of 300 DPI in a staggered manner, so that 256 nozzles of 600 DPI can be formed as a recording head. The substrate 1 is arranged in a silicon substrate material for 200 chips.
[0055]
Next, in order to form a dissolvable ink flow path pattern 3 as shown in FIGS. 2A and 2B, a positive resist ODUR1010 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied using spin coating. Filmed. After that, pattern exposure (exposure time: 3 minutes) was performed through a mask using a mask aligner PLA620 (compatible with deep UV) manufactured by Canon Inc., and then development was performed to form an ink flow path pattern 3. The design shape of the ink flow path pattern 3 is as shown in FIG. 7 (corresponding to a cross-sectional view along the line BB ′ in FIG. 1), and has a width of 33 μm and a film thickness of 13 μm. The width of the electrothermal transducer 2 is 30 μm, and the distance between adjacent electrothermal transducers 2 is 84.5 μm.
[0056]
The film thickness of the ink flow path pattern 3 of 10 nozzles in one substrate (1 chip) 1 is set to the film thickness of the ink flow path pattern 3 for 10 substrates (10 chips), ie, 100 nozzles in total. As a result of measurement by a total meter (λ ace), the average film thickness was 13.1 μm (the variation was σ = 0.1 μm), and it was confirmed that the film was formed to have a substantially uniform film thickness.
[0057]
Next, in order to form the coating resin layer 4 as shown in FIGS. 3A and 3B, the coating resin composition shown in Table 3 below was dissolved in 2-ethoxyethanol as a coating solvent at a concentration of 50 wt%. Then, it was applied on the ink flow path pattern 3 by spin coating. The application is performed while adjusting the spin rotation speed so that the coating resin layer 4 has a thickness of 12 μm. Thereafter, the coating was baked at a temperature of 90 ° C. for 3 minutes to dry the coating solvent.
[0058]
[Table 3]

[0059]
Next, the discharge port 5 is formed as shown in FIGS. In the case of this example, since the coating resin layer 4 contains a photocationic polymerization initiator and has negative photosensitive characteristics, the discharge ports 5 are formed by photolithography. That is, using a mask aligner PLA620 made by Canon, pattern exposure (exposure time: 4 seconds) is performed through a mask, and then heat treatment is performed at a temperature of 90 ° C. for 3 minutes, and then development processing is performed to form the discharge port 5 did. The diameter of the discharge port 5 was formed to be φ20 μm.
[0060]
Next, anisotropic etching of silicon was performed from the back surface of the silicon substrate 1 through a mask to form an ink supply port 6 as shown in FIGS. 5A and 5B. Next, after the ink flow path pattern remaining in the present process was decomposed by whole-surface exposure, it was removed with methyl lactate as shown in FIGS. 6 (a) and 6 (b). Thereafter, in order to completely cure the coating resin layer 4, a heat treatment was performed at a temperature of 200 ° C. for one hour.
[0061]
After forming the nozzle structure in this manner, the OH distance between the electrothermal conversion element 2 and the surface on which the discharge port 5 was formed was measured using an interference film thickness meter (Zygo new view 200). The measurement points of the OH distance were 10 nozzles in one substrate (1 chip) 1 for 10 substrates (10 chips), that is, a total of 100 nozzles. The average of the OH distances for the 100 nozzles was 25.0 μm (variation: σ = 0.04 μm).
[0062]
As a comparative object of such a nozzle structure of this embodiment, methyl isobutyl ketone described in Example 1 of the above-mentioned JP-A-6-286149 was used instead of 2-ethoxyethanol as a coating solvent for the coating resin. / Xylene = 1/1 (parts by weight) to form a coating resin layer 4. As a result of measuring the OH distance of the sample to be compared by the measurement method described above, the average was 24.9 μm (the variation was σ = 0.9 μm). Although the average value of the OH distance in the above-described embodiment of the present invention and the average value of the OH distance in the sample to be compared with each other are both formed to approximately the designed value of 25 μm, the variation of the OH distance It was confirmed that the value was reduced to half or less in the case of the former example of the present invention as compared with the latter comparative sample.
[0063]
Furthermore, for each of the former nozzle structure in the embodiment of the present invention and the latter nozzle structure in the sample to be compared, an electrical connection and an ink tank supply member are arranged to form a recording head. Ink droplets were ejected from both of these recording heads. As a result of measuring the ejection amount of ink droplets from one nozzle per one recording head for each of the two recording heads for ten recording heads, the ink droplets in the former recording head according to the embodiment of the present invention were determined. Was 8.5 picoliters, and the variation was ± 0.3 picoliters. On the other hand, the average value of the ejection amount of the ink droplets in the latter comparative sample was 8.5 picoliters, and the variation was ± 0.6 picoliters. As is clear from the comparison between the two, the recording head using 2-ethoxyethanol (ethyl cellosolve) as the coating solvent as in the example of the present invention reflects the ink droplets reflecting the reduction in variation in OH accuracy. The variation in the discharge amount can be kept small.
[0064]
(Example 2 of the second embodiment)
In this embodiment, an ink jet recording head was manufactured according to the procedure shown in FIGS. First, two rows of 24 μm square electrothermal transducers (tantalum nitride TaN) 2 were arranged on a silicon substrate 1 in the form shown in FIG.
The electrothermal transducers 2 are arranged for 300 nozzles, and are arranged in two rows at a pitch of 600 DPI in a staggered manner, so that 300 nozzles of 1200 DPI can be formed as a recording head. The substrate 1 is arranged on a silicon substrate material for 250 chips.
[0065]
Next, in the same manner as in Example 1 described above, the ink flow path pattern 3 was formed with a soluble resin as shown in FIGS. 2 (a) and 2 (b). The design shape of the ink flow path pattern 3 is as shown in FIG. 8 (corresponding to a cross-sectional view along the line BB ′ in FIG. 1), and has a width of 30 μm and a film thickness of 13 μm. The width of the electrothermal transducer 2 is 24 μm, and the distance between adjacent electrothermal transducers 2 is 42.5 μm.
[0066]
The film thickness of the ink flow path pattern 3 of 10 nozzles in one substrate (1 chip) 1 is set to the film thickness of the ink flow path pattern 3 for 10 substrates (10 chips), ie, 100 nozzles in total. As a result of measurement by a total meter (λ ace), the average film thickness was 13.0 μm (the variation was σ = 0.1 μm), and it was confirmed that the film was formed to have a substantially uniform film thickness.
[0067]
Next, in order to form the coating resin layer 4 as shown in FIGS. 3A and 3B, the coating resin composition shown in Table 4 below was dissolved in 2-ethoxyethanol as a coating solvent at a concentration of 50 wt%. Then, it was applied on the ink flow path pattern 3 by spin coating. The application is performed while adjusting the spin rotation speed so that the coating resin layer 4 has a thickness of 12 μm. Thereafter, the coating was baked at a temperature of 90 ° C. for 3 minutes to dry the coating solvent.
[0068]
[Table 4]

[0069]
Next, the discharge port 5 is formed as shown in FIGS. In the case of this example, since the coating resin layer 4 contains a photocationic polymerization initiator and has negative photosensitive characteristics, the discharge ports 5 are formed by photolithography. That is, using a mask aligner MPA600 made by Canon, pattern exposure (exposure time: 60 seconds) is performed through a mask, and then heat treatment is performed at a temperature of 90 ° C. for 3 minutes, and then a developing treatment is performed to form the discharge port 5 did. The diameter of the discharge port 5 was formed to be φ15 μm.
[0070]
Next, anisotropic etching of silicon was performed from the back surface of the silicon substrate 1 through a mask to form an ink supply port 6 as shown in FIGS. 5A and 5B. Next, after the ink flow path pattern remaining in the present process was decomposed by whole-surface exposure, it was removed with methyl lactate as shown in FIGS. 6 (a) and 6 (b). Thereafter, in order to completely cure the coating resin layer 4, a heat treatment was performed at a temperature of 200 ° C. for one hour.
[0071]
After forming the nozzle structure in this manner, the OH distance between the electrothermal conversion element 2 and the surface on which the discharge port 5 was formed was measured using an interference film thickness meter (Zygo new view 200). The measurement points of the OH distance were 10 nozzles in one substrate (1 chip) 1 for 10 substrates (10 chips), that is, a total of 100 nozzles. The average of the OH distances for the 100 nozzles was 25.0 μm (the variation was σ = 0.3 μm).
[0072]
Further, an electrical connection and an ink tank supply member were arranged for such a nozzle structure to form a recording head, and ink droplets were ejected from the recording head. As a result of measuring the ejection amount of the ink droplet from one nozzle per one recording head for ten recording heads, the average value of the ejection amount of the ink droplet was 5.0 picoliters, and the variation was ± 0.2 picoliters. Met. As described above, although the ink ejection amount per nozzle is a very small amount of 5 picoliters, the variation can be suppressed to an extremely small range.
[0073]
In Examples 1 and 2 described above, as in the first embodiment of the present invention described above, by keeping the coating resin layer 4 under reduced pressure after completion of application, the appearance rate of thin film-like dust is suppressed, The manufacturing yield of the recording head can be improved. The synergistic effect of these combinations can greatly improve the reliability of the recording head.
[0074]
(Example of the overall configuration of the inkjet recording head)
FIG. 9 is a perspective view for explaining an overall configuration example of the ink jet recording head of the present invention.
[0075]
In FIG. 9, reference numeral 2 denotes an element substrate having a nozzle structure in the first and second embodiments described above, and a plurality of discharge ports 4 arranged in two rows are provided in a staggered manner. The element substrate 2 is bonded and fixed to a part of the support member 102 processed into an L shape. The wiring portion of the wiring substrate 104 fixed on the support member 102 and the wiring portion of the element substrate 2 are electrically connected by bonding. The support member 102 is formed of an aluminum material from the viewpoint of cost, workability, and the like. The mold member 103 inserts a part of the support member 102 therein to support the support member 102, and also supplies the above-described ink supply from the ink storage unit through an ink supply path formed therein. This is a member for supplying ink to the opening 6. Further, the mold member 103 plays a role as a mounting and positioning member for detachably fixing the entire recording head of this embodiment to the ink jet recording apparatus.
[0076]
(Structural example of inkjet recording device)
FIG. 10 is a schematic perspective view of a serial type ink jet recording apparatus that can use the ink jet recording head of the present invention.
[0077]
In FIG. 10, reference numeral 200 denotes a carriage on which the above-described inkjet recording head of the present invention is detachably mounted. In the case of this example, four types of recording heads are mounted according to the types of ink colors, and are mounted on the carriage 200 together with the yellow ink tank 201Y, the magenta ink tank 201M, the cyan ink tank 201C, and the black ink tank 201B. Be mounted.
[0078]
The carriage 200 is supported by a guide shaft 202 and is reciprocated in the direction of arrow A (main scanning direction) along the guide shaft 202 by an endless belt 204 driven in a forward or reverse direction by a motor 203. Endless belt 204 is stretched between pulleys 205 and 206.
[0079]
The recording paper P as a recording medium is intermittently conveyed in a direction of arrow B (sub-scanning direction) perpendicular to the direction of arrow A. The recording paper P is sandwiched between a pair of roller units 207 and 208 on the upstream side and a pair of roller units 209 and 210 on the downstream side, and a constant tension is applied to the recording paper P while securing flatness with respect to the recording head. Conveyed. The driving force for each roller unit is provided from the driving unit 211. Further, each roller unit may be configured to be driven by the motor 203.
[0080]
The carriage 200 stops at the home position as necessary during the start of printing or during the printing operation. The position is provided with a cap member 212 for capping the ejection port surface of each recording head. The cap member 212 is connected to suction recovery means for forcibly sucking ink not contributing to image recording from the discharge ports opened on the discharge port surface to prevent clogging in the discharge ports.
[0081]
(Other)
In addition, the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for causing ink to be ejected, particularly in an ink jet recording system. The present invention brings about an excellent effect in a recording head and a recording apparatus of a type that causes a change in the state. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.
[0082]
Regarding the typical configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the liquid path holding the liquid (ink). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby causing the electrothermal transducer to generate thermal energy, and This is effective because film boiling occurs on the heat-acting surface of the liquid, and as a result, air bubbles in the liquid (ink) corresponding to this drive signal one-to-one can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is in a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in U.S. Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.
[0083]
As the configuration of the recording head, in addition to the combination configuration (straight liquid flow path or right-angle liquid flow path) of the discharge port, liquid path, and electrothermal converter as disclosed in the above-mentioned specifications, A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which a is bent, is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be performed reliably and efficiently regardless of the form of the recording head.
[0084]
Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by combining a plurality of recording heads, or a configuration as a single recording head that is integrally formed.
[0085]
In addition, even with the serial type printer as in the above example, the recording head fixed to the main unit or attached to the main unit enables electrical connection with the main unit and supply of ink from the main unit. The present invention is also effective when a replaceable chip-type recording head or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.
[0086]
Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. Specifically, heating is performed on the recording head by using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer or another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.
[0087]
Regarding the type or number of print heads to be mounted, for example, in addition to one provided for single color ink, a plurality of print heads are provided corresponding to a plurality of inks having different print colors and densities. May be used. That is, for example, the printing mode of the printing apparatus is not limited to the printing mode of only the mainstream color such as black, but may be any of integrally forming the printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.
[0088]
In addition, in the embodiments of the present invention described above, the ink is described as a liquid, but an ink that solidifies at room temperature or below and that softens or liquefies at room temperature may be used, or In general, in the ink jet method, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. A liquid may be used. In addition, in order to positively prevent the temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent the ink from evaporating, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink is held in a state of being held as a liquid or solid substance in the concave portion or through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.
[0089]
In addition, as the form of the ink jet recording apparatus of the present invention, in addition to a form used as an image output terminal of an information processing device such as a computer, a form of a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function are adopted. Or the like.
[0090]
【The invention's effect】
As described above, the present invention provides a method for forming a coating resin layer serving as an ink flow path wall on an ink flow path pattern on a substrate formed of a dissolvable resin. By maintaining the reduced pressure state, the removal of the solvent of the coating resin forming the coating resin layer is promoted, and the compatibility between the ink flow path pattern and the coating resin layer, which becomes dust in the final manufacturing process of the recording head, is improved. The generation of layers can be avoided, and the production yield of the inkjet recording head can be improved.
[0091]
Further, by using a solvent containing 2-ethoxyethanol as a solvent of the coating resin for forming the coating resin layer, the flatness of the surface of the coating resin layer is improved, and the variation in the ink ejection amount is suppressed to an extremely small range. be able to.
[Brief description of the drawings]
FIG. 1 is a perspective view of a substrate constituting a recording head of the present invention.
2A is a cross-sectional view taken along line AA ′ of FIG. 1 in an ink flow path pattern forming step of the recording head of the present invention, and FIG. 2B is a view in the ink flow path pattern forming step. FIG. 1 is a sectional view taken along line BB ′ of FIG.
3A is a cross-sectional view taken along the line AA ′ of FIG. 1 in a step of forming a coating resin layer of the recording head of the present invention, and FIG. 3B is a cross-sectional view of FIG. It is sectional drawing which follows the -B 'line.
4A is a cross-sectional view taken along the line AA ′ of FIG. 1 in a discharge port forming step of the recording head of the present invention, and FIG. 4B is a sectional view of FIG. It is sectional drawing which follows the 'line.
5A is a sectional view taken along the line AA ′ of FIG. 1 in an ink supply port forming step of the recording head of the present invention, and FIG. 5B is a sectional view of FIG. 1B in the ink supply port forming step; It is sectional drawing which follows the -B 'line.
6A is a cross-sectional view taken along the line AA ′ of FIG. 1 in a coating resin layer dissolving stage of the recording head of the present invention, and FIG. 6B is a sectional view of FIG. It is sectional drawing which follows the -B 'line.
FIG. 7 is an enlarged sectional view of a main part of Example 1 of a recording head according to a second embodiment of the present invention.
FIG. 8 is an enlarged sectional view of a main part of Example 2 of a recording head according to a second embodiment of the present invention.
FIG. 9 is a perspective view illustrating a configuration example of the entire recording head of the present invention.
FIG. 10 is a perspective view of a main part of a recording apparatus that can use the recording head of the present invention.
[Explanation of symbols]
1 Substrate (base)
2 Electrothermal conversion element
3 Ink channel pattern
4 coating resin layer
5 Discharge port
6 Ink supply port

Claims (11)

On a substrate provided with a discharge energy generating element that generates ink discharge energy,
(1) a step of forming an ink flow path pattern with a soluble resin;
(2) dissolving a coating resin containing a solid epoxy resin at room temperature in a solvent, and solvent-coating the coating resin on a dissolvable resin layer forming the ink flow path pattern; A step of forming a coating resin layer serving as an ink flow path wall on the layer,
(3) a step of forming an ink discharge port in a portion of the coating resin layer located above the discharge energy generating element;
(4) a step of eluting the soluble resin layer;
In a method for manufacturing an ink jet recording head having
A method for manufacturing an ink jet recording head, comprising a step of maintaining the coating resin layer under reduced pressure after solvent coating for forming the coating resin layer. 2. The method according to claim 1, wherein the reduced pressure is 30 cmHg or less. The method according to claim 1, wherein the reduced pressure state is a temperature of 50 ° C. or less. 4. The method according to claim 1, wherein the dissolvable resin forming the ink flow path pattern is an ionizing radiation decomposable resin, and contains a polymer of methyl isopropenyl ketone in its molecular structure. 5. A method for manufacturing an ink jet recording head. 5. The method according to claim 1, wherein the solvent in which the coating resin is dissolved contains xylene. 6. The method according to claim 1, wherein the solvent in which the coating resin is dissolved contains 2-ethoxyethanol. 7. The method according to claim 1, wherein the discharge energy generating element is an electrothermal converting element that generates thermal energy. An ink jet recording head manufactured by the method according to claim 1. In an inkjet recording apparatus capable of recording an image on a recording medium using an inkjet recording head,
8. An ink jet recording apparatus using an ink jet recording head manufactured by the method according to claim 1 as the ink jet recording head. First moving means for relatively moving the inkjet recording head and the recording medium in the main scanning direction;
The inkjet recording apparatus according to claim 9, further comprising: a second moving unit that relatively moves the inkjet recording head and the recording medium in a sub-scanning direction that intersects the main scanning direction. A moving unit that relatively moves the inkjet recording head and the recording medium in a longitudinal direction of the recording medium,
10. The ink jet recording apparatus according to claim 9, wherein the ink ejection port is formed at a position of the ink jet recording head facing a whole recording area in a width direction of the recording medium.

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