JP3582754B2 - Ink jet recording device - Google Patents

Description

測定２
第２の測定結果を第２表に示す。
【００９４】
ヒーターの構成は、ＨＷ_Ａ ＝２１μｍ，ＨＬ_Ａ ＝１３６μｍ，ＯＨ_Ａ ＝１００μｍとＨＷ_Ｂ ＝１９μｍ，ＨＬ_Ｂ ＝１３７μｍ，ＯＨ_Ｂ ＝１４０μｍとした。この場合も第１の実施例と同じく高画質な印字を行うのに充分な結果が得られた。
【００９５】
つまり、ヒーターの形状や大きさを変化させてもＯＨ距離の差を適当な値にすれば、良好な結果が得られる。
【００９６】
【表２】

測定３
次に、ＯＨ距離の差に対する吐出速度とインクミストの関係を第３表に示す。ヒーターＡのＯＨ距離と小液滴の吐出速度とインクミストの関係を第３表（ａ）に、２つのヒーターのＯＨ距離の差と大液滴の吐出速度ととインクミストの関係を第３表（ｂ）に示した。このときのヒーターサイズは実施例１と同じくＨＷ_Ａ ＝２２μｍ，ＨＬ_Ａ ＝１３５μｍとＨＷ_Ｂ ＝２４μｍ，ＨＬ_Ｂ ＝１３５μｍとした。
【００９７】
第３表（ａ）において、小液滴の吐出速度はヒーターＡのＯＨ距離が１２０μｍを超えると徐々に遅くなり、高品位な印字を期待できない。また７０μｍ以下になるとインクミスト量が増大する。これはリフィル周波数ｆｒが悪くなり、吐出状態が不安定となるためと考えられる。
【００９８】
第３表（ｂ）については、ヒーターＡのＯＨ距離は１００μｍとし、ヒーターＢのＯＨ距離に対して大液滴の吐出速度を示した。ＯＨ距離が１１０μｍを下回ると大液滴吐出時にインクミストが発生し、吐出方向が曲がり液滴着弾精度が低下する。また、ＯＨ距離が２００μｍ以上では、たまに不吐出が発生した。
【００９９】
したがって、小液滴の吐出速度を上昇させ、且つ大液滴吐出時のインクミストの発生を抑止し、安定した吐出を行なわせるには、小液滴を吐出するためのヒーターのＯＨ距離を８０〜１３０μｍとし、２つのヒーターのＯＨ距離の差を１０〜８０μｍにすればよい。さらに高画質な記録品位を求めるならば、前記ＯＨ距離の差を２０〜６０μｍにすればよい。
【０１００】
【表３】

測定４
次に、後ろ側ヒータの距離ＯＨを１７０μｍに固定とし、前側ヒータの位置を変化させたときの吐出特性を測定した。測定は、吐出口面積ＳＯや前ヒータおよび後ろ側ヒータ面積ＳＨが異なるものについて行った。結果を第４表および第５表に示し、これらをグラフ化したものを図１３および図１４に示す。図１３および図１４において、（ａ）は吐出速度ｖ、（ｂ）は吐出量Ｖｄ、（ｃ）は吐出速度ｖを吐出量Ｖｄで除いた値であり、これらはともに前側ヒータのみを用いた場合と前側ヒータおよび後ろ側ヒータを同時に用いた場合が示さている。（ｄ）は各場合の位置ずれ量を示している。
【０１０１】
第４表に測定結果が示される測定では吐出口面積ＳＯが３８０μｍ^２、前側ヒータおよび後ろ側ヒータのいずれも面積ＳＨが１７μｍ×１３５μｍのものを用いた。第５表に測定結果が示される測定では、吐出口面積ＳＯが４００μｍ^２、前側ヒータの面積ＳＨが１７μｍ×１１５μｍ、後ろ側ヒータの面積ＳＨが２３μｍ×１１５μｍのものを用いた。いずれの測定においても、測定は使用インクは表面張力約２６．０〜３７．０（ｄｙｎｅ／ｃｍ）であり、粘度が１．８５〜２．６０（ｃＰ）のものを用い、小ドットおよび大ドット吐出を行った際の吐出速度ｖＦおよびｖＦ＋Ｂと吐出量ＶｄＦおよびＶｄＦ＋Ｂについて測定を行い、上記のような構成のインクジェット記録ヘッドを走査速度が０．７（ｍ／ｓ）のキャリッジに搭載し、記録媒体までの距離が１ｍｍの記録装置に搭載したときの記録的の飛翔時間および着弾位置ずれを求め、さらに、小ドット吐出時の吐出速度を吐出量で除した第１の値と、大ドット吐出時の吐出速度を吐出量で除した第２の値とを求め、さらに第１の値を第２の値で除した値を求めている。
【０１０２】
【表４】

【０１０３】
【表５】

上記の測定結果から、第１の値が第２の値に比例係数１．１５を乗じた値よりも大きなとき、すなわち、吐出速度ｖＦ，ｖＦ＋Ｂおよび吐出量吐出量ＶｄＦ，ＶｄＦ＋Ｂが、
（ｖＦ／ＶｄＦ）≧（ｖＦ＋Ｂ／ＶｄＦ＋Ｂ）×Ｃ
（Ｃは定数）
の関係を満たすように配置することにより、好ましい吐出速度、吐出量比、着弾位置ずれ量およびリフィル周波数が得られることが判った。定数Ｃはインク物性等によって変わるもので、本発明者の実験によれば表面張力が約２６．０〜３７．０（ｄｙｎｅ／ｃｍ）であり、粘度が１．８５〜２．６０（ｃＰ）のインクを用いたときには、Ｃ＝１．１５となり、表面張力が約４０．５〜４６．５（ｄｙｎｅ／ｃｍ）であり、粘度が１．５〜２．１（ｃＰ）のインクを用いたときには、Ｃ＝１．０となることが判った。
【０１０４】
次に、本発明の第２の実施例について説明する。本実施例はヒータの形状および重心位置に関するものである。
【０１０５】
ヒータを加熱させてその上のインクを発泡させてインク滴を吐出させるインクジェット記録装置において所定のインク滴体積を得るためには、所定の面積のヒータが必要となる。
【０１０６】
ノズルを高密度化していくためにはヒータ幅を狭くする必要があるが、このとき、幅の大きなヒータと同じインク滴体積とするためにはヒータ面積を等しくする必要があり、必然的にヒータ長さを大きくすることとなる。１ノズル内に複数のヒータをノズル列方向に並設する場合には幅はさらに狭くなり、ヒータ長さもより大きなものとなる。
【０１０７】
図１５（ａ），（ｂ）のそれぞれは、上記の特性を考慮した第２の実施例を説明するための図で、ほぼ同じインク滴を吐出するノズル１００１，１００５の構成を示す平面図であり、ヒータ形状により特性が異なるものとなることを説明するための図である。
【０１０８】
ノズル１００１内には２つのヒータ１００２と１００３が配設され、ノズル１００１と同形状のノズル１００５内にはヒータ１００６と１００８が配設されている。ヒータ１００２（１００３）はヒータ１００６（１００８）と幅が小さく、長さが大きいが、面積はほぼ等しいものとされ、また、各ヒータのノズル１００１および１００５に対する重心の位置は等しくなるように配設されている。このような条件で配設されることにより、図１５（ａ）に示すノズル１００１における吐出口１００４から前側ヒータ１００２までの距離ＯＣ１は図１５（ｂ）に示すノズル１００５における吐出口１００７から前側ヒータ１００６までの距離ＯＣ２よりも短いものとなる。この結果、ヒータ１００２の端部はＢ領域に配置され、吐出量Ｖｄが小さくなる。また、発泡中心となる吐出口１００４から重心までの距離は、幅の広い、図１５（ｂ）に示したものと同じであり、各ヒータの重心はＡ領域となるため、リフィル周波数ｆｒに関してはこれらはいずれもほぼ等しいものとなり、小液滴の形成と効率良くリフィルを行うことが両立できるものとなっている。
【０１０９】
次に、本発明の第３の実施例について説明する。
【０１１０】
本実施例は、上記のＡ領域とＡ領域以外のＢ領域およびＣ領域の分岐点を図４に示した内容から１３０μｍと規定し、さらに、各測定結果からインクの種類に応じて吐出速度ｖＦ，ｖＦ＋Ｂおよび吐出量吐出量ＶｄＦ，ＶｄＦ＋Ｂを規定するものである。
【０１１１】
これらの各パラメータは以下により説明され、規定することができる。
【０１１２】
表面張力が約２６．０〜３７．０（ｄｙｎｅ／ｃｍ）であり、粘度が１．８５〜２．６０（ｃＰ）のインクを用いたときには、
ｖＦ≧８（ｍ／Ｓ）
ｖＦ＋Ｂ≦１６（ｍ／Ｓ）
ＶｄＦ≦２５（ｐｌ）
３５≦ＶｄＦ＋Ｂ≦４５（ｐｌ）
の関係を満たすこととする。
【０１１３】
また、表面張力が約４０．５〜４６．５（ｄｙｎｅ／ｃｍ）であり、粘度が１．５〜２．１（ｃＰ）のインクを用いたときには、
ｖＦ≧７．５（ｍ／Ｓ）
ｖＦ＋Ｂ≦１６（ｍ／Ｓ）
ＶｄＦ≦４０（ｐｌ）
６５≦ＶｄＦ＋Ｂ≦８０（ｐｌ）
の関係を満たすこととする。上記のような条件のときに大小吐出を良好に行うことができる。
【０１１４】
図１６は、上記のような各特性を備えたインクジェット記録ヘッドを用いたインクジェトヘッドカートリッジＡ〜Ｄを組み合せたものである。インクジェトヘッドカートリッジＡ〜Ｄにはカラー記録を行うためにＹ（イエロー）、Ｍ（マゼンタ）、Ｃ（シアン）、Ｂｋ（ブラック）がそれぞれ供給される。ここで、インクジェトヘッドカートリッジＡ〜Ｃを構成するインクジェット記録ヘッドは、上記の定数Ｃが１．１５となるものが使用され、インクジェトヘッドカートリッジＤには上記の定数Ｃが１．００となるものが使用されている。
【０１１５】
上述した各実施例の実施形態としては、図１７（ａ）に示す例では同形状の両ヒータの一部が隣接するように配置されたもの、図１７（ｂ）に示すように同形状の両ヒータが隣接しないように配置されたもの、図１７（ｃ）に示すように異なる形状のヒータの一部が隣接するように配置されたもの、図１７（ｄ）に示すように異なる形状の両ヒータが隣接しないように配置されたものの全てが含まれる。
【０１１６】
なお、上述した各実施例においては、ヒータが２つ設けられたものを例として説明したが、さらに多くのヒータを配置する場合であっても本発明の考え方を適用することができる。例えば、１箇所に複数のヒータが並設される場合にはこれらを１つのヒータと見なしてその重心に本発明を適用すればよい。また、距離ＯＨが異なるように設けられた場合には、前後関係を持つヒータを１つのヒータと見なしてその重心に本発明を適用すればよい。
また、上述した各実施例を組み合せることにより、各実施例における効果が相乗したものとなり、このように構成してもよい。
【０１１７】
図１８は上記のように構成されるインクジェット記録ヘッドを用いたインクジェットヘッドカートリッジの一例を示す分解斜視図である。
【０１１８】
図１８において記録ヘッドユニットＩＪＵは、電気信号に応じて熱エネルギーを生成しインクに膜沸騰を生じさせることによりインク吐出を行う方式のユニットである。ヒータボード１００は、Ｓｉ基板上に、複数の列状に配された上記熱エネルギーを生成するための電気熱変換素子（吐出ヒータ）と、これに電力を供給するＡｌ等の電気配線とが成膜技術により形成されて成る、配線基板２００は、ヒータボード１００の配線に対応する配線（例えばワイヤボンディングにより接続される）と、この配線の端部に位置し本体装置からの電気信号を受けるパッド２０１とを有している。天板１３００は、複数のインク吐出口のそれぞれに対応したインク路や共通液室等を構成するための隔壁を具え、また、インクタンクから供給されるインクを受けて共通液室へ導入するためのインク受け口１５００と、吐出口を複数有するオリフィスプレート４００を一体に具える。天板１３００が具える隔壁等は天板１３００と一体成型されるものであり、これらの一体成型材料としてはポリサルフォンが好ましいが、他の成型用樹脂材料でも良い。
【０１１９】
支持体３００は配線基板２００の裏面を平面で支持し、例えば金属によって形成され、記録ヘッドユニットの構造部材をなす。押えばね５００はＭ字形状をなし、そのＭ字の中央で天板１３００の共通液室に対応する部分を押圧すると共に前だれ部５０１で同様に天板１３００のインク路に対応する部分を線接触で押圧する。押えばね５００の足部が支持体３００の穴３１２１を通って支持体３００の裏面側に係合することにより、ヒータボード１００および天板１３００を支持体３００との間に挟み込んだ状態とし、これにより、押えばね５００とその前だれ部５０１の付勢力によってヒータボ−ド１００と天板１３００とを支持体３００に圧着固定することができる。支持体３００は、インクタンクに設けられた２つの位置決め凸起１０１２および２つの位置決め且つ熱融着保持用凸起１８００のそれぞれに係合するそれぞれ２つの位置決め用穴３１２，１９００を有する他、ヘッドカートリッジの装置本体側キャリッジに対する位置決め用の突起２５００，２６００を裏面側に有している。加えて支持体３００はインクタンクからのインク供給を可能とするインク供給管２２００（後述）を貫通可能にする穴３２０をも有している。支持体３００に対する配線基板２００の取付は、接着剤等で貼着して行われる。
【０１２０】
なお、支持体３００の凹部２４００，２４００は、それぞれ位置決め用突起２５００，２６００の近傍に設けられており、これら凹部は、組立てられたヘッドカートリッジ（図１９に示される）において、ヘッドカートリッジにおける記録ヘッドユニットＩＪＵの周囲の３辺に形成されたそれぞれ複数の平行溝３０００，３００１延長点にあって、ゴミやインク等の不要物が突起２５００，２６００に至ることがないように設けられている。平行溝３０００が形成される蓋部材８００は、ヘッドカートリッジの外壁を形成すると共に、記録ヘッドユニットＩＪＵを収納する部分を形成している。また、平行溝３００１が形成されるインク供給路部材６００は、前述したインク供給管２２００と接続することによりこれにインク連通するインク導管１６００を、供給管２２００との接続側が固定の片持ちばり形態で具え、また、インク導管１６００の固定部においてインク供給管２２００との毛管現象を確保するための封止ピン６０２を具える。尚、６０１はインクタンクと供給管２２００との結合シールを行うパッキン、７００は供給管２２００のタンク側端部に設けられたフィルターである。インク供給路部材６００は、モールド成型されているため、廉価で位置精度が高く形成されるばかりでなく、片持ちばり形態の導管１６００によって大量生産時においても導管１６００の、天板１３００のインク受け口１５００に対する圧接状態を安定化できる。本例では、この圧接状態下で封止用接着剤をインク供給路部材側から流し込む。
【０１２１】
なお、インク供給路部材６００の支持体３００に対する固定は、支持体３００の穴１９０１，１９０２に対するインク供給路部材６００の裏面側ピン（不図示）を支持体３００の穴１９０１，１９０２を介して貫通突出せしめ、支持体３００の裏面側に突出した部分を熱融着することで簡単に行われる。尚、この熱融着された裏面部のわずかな突出領域は、インクタンクの記録ヘッドユニットＩＪＵ取付面側壁面のくぼみ（不図示）内に収められるのでユニットＩＪＵの位置決め面は正確に得られる。
【０１２２】
インクタンクは、カートリッジ本体１０００と、インク吸収体９００と、インク吸収体９００をカートリッジ本体１０００の上記ユニットＩＪＵ取付面とは反対側の側面から挿入した後、これを封止するための蓋１１００と、で構成されている。吸収体９００は、カートリッジ本体１０００内に配置される。供給口１２００は上記各部１００〜６００からなるユニットＩＪＵに対してインクを供給するための供給口であり、当該ユニットをカートリッジ本体１０００の部分１０１０に配置する前の工程で供給口１２００よりインクを注入することにより吸収体９００のインク含浸を行うための注入口でもある。本例のヘッドカートリッジでは、インクをインクタンク内に注入できる部分は、大気連通口１４０１と供給口１２００である。しかしながら、本体１０００内側面に設けられたリブ２３００および蓋１１００の内側面に設けられたリブ２５００，２５０１とによってそれぞれ形成されるタンク内空気存在領域を、大気連通口１４０１側から連続した部分に設け、かつインク供給口１２００から最も遠い角部域にわたって設けた構成をとることにより、インク吸収体からのインク供給性を良好に保っている。このため、相対的に良好かつ均一な吸収体へのインク注入は、供給口１２００を介して行われることが重要である。この方法は実用上極めて有効である。リブ２３００は、カートリッジ本体１０００の後方において、キャリッジ移動方向に平行なリブを４本（図１８には上面の２本のみ示される）有し、吸収体が本体１０００の面に密着することを防止している。また、部分リブ２５０１，２５００は、リブ２３００の延在する方向の延長上にあって蓋１１００の内側面に設けられているが、リブ２３００とは異なり分割された状態となっている。これにより、空気の存在空間を前者より増加させている。なお、リブ２５００，２５０１は蓋１１００の全面積の半分以下の面に分散された形となっている。これらのリブによってインク吸収体９００のタンク供給口１２００から最も遠い角部の領域のインクをより安定させつつも確実に供給口１２００側へ毛管力で導くことができる。１４０１はインクタンク内部を大気に連通するために蓋部材に設けられた大気連通口である。１４００は大気連通口１４０１の内方に配置される揆液材であり、これにより大気連通口１４００からのインク漏洩が防止される。
【０１２３】
インクタンクのインク収容空間は長方形形状であり、その長辺を側面に持つ場合であるので上述したリブの配置構成は特に有効であるが、キャリッジの移動方向に長辺を持つ場合又は立方体の場合は、蓋１１００の全体にリブを設けるようにすることでインク吸収体９００からのインク供給を安定化できる。
【０１２４】
インクタンクおよび、これにユニットＩＪＵが装着された後にユニットＩＪＵを覆う蓋８００によって、ユニットＩＪＵは下方開口を除いて包囲されることになるが、ヘッドカートリッジは、装置本体側のキャリッジに装着され、この際、上記下方開口はキャリッジと近接するため、実質的な４方包囲空間が形成される。従って、この包囲空間内にある記録ヘッドＩＪＨからの発熱は、この空間内に均一に分散してこの空間を均一な温度に保つものとして有効となる。しかしながら、ヘッドＩＪＨが長期連続して駆動された場合など、わずかな昇温を生じることがある。このため、本例では、支持体３００からの自然放熱を助けるためにカートリッジの上方面に、この空間よりは小さい幅のスリット１７００を設けて、昇温を防止しつつもユニットＩＪＵ全体の温度分布の均一化を環境に左右されないようにする。
【０１２５】
図１９に示されるようにヘッドカートリッジＩＪＣとして組立てられると、インクはインクタンクの供給口１２００から支持体３００に設けた穴３２０および供給タンク６００の中裏面側に設けた導入口を貫ぬいて配される供給管２２００を介してインク供給路部材６００内の導管１６００に導かれ、その内部を通った後、天板１３００のインク導入口１５００を介して共通液室内へと流入される。以上における供給管および導管の接続部には、例えばシリコンゴムやブルチゴム等のパッキンが配設され、これによって封止が行われてインク供給路が確保される。
【０１２６】
なお、本実施例においては、天板１３００は耐インク性に優れたポリサルフォン，ポリエーテルサルフォン，ポリフェニレンオキサイド，ポリプロピレンなどの樹脂を用い、オリフィスプレート部４００と共に金型により一体に同時成型してある。
【０１２７】
図２０は本発明のインクジェット記録ヘッドカートリッジを用いたインクジェット記録装置ＩＪＲＡの概観図である。記録ヘッドとインクタンクとが一体となったインクジェットカートリッジＩＪＣは、キャリッジＨＣに搭載される。キャリッジＨＣは駆動モータ５０１３の正転逆転に連動して駆動力伝達ギア５０１１，５０００９を介して回転するリードスクリュー５００４の螺旋溝５００５に対して係合するキャリッジＨＣはピン（不図示）を有し、矢印ａ，ｂ方向に往復移動される。キャリッジＨＣには記録ヘッド部５０２５，インクタンク部５０２６が装着される。５００２は紙押え板であり、キャリッジの移動方向にわたって紙をプラテン５０００に対して押圧する。５００７，５００８はフォトカプラであり、キャリッジのレバー５００６のこの域での存在を確認してモータ５０１３の回転方向切り替え等を行うためのホームポジション検知手段である。５０１６は記録ヘッドの前面をキャップするキャップ部材５０２２を支持する部材、５０１５はこのキャップ内を吸引する吸引手段であり、キャップ内開口５０２３を介して記録ヘッドの吸引回復を行う。５０１７はクリーニングブレード、５０１９はこのブレードを前後方向に移動可能にする部材であり、本体支持板５０１８にこれらは支持されている。ブレードは、この形態でなく周知のクリーニングブレードが本例に適用できることはいうまでもない。また、５０１２は、吸引回復の吸引を開始するためのレバーであり、キャリッジと係合するカム５０２０の移動に伴って移動し、駆動モータからの駆動力がクラッチ切り替え等の公知の伝達手段で移動制御される。
【０１２８】
これらのキャッピング，クリーニング，吸引回復は、キャリッジＨＣがホームポジション側領域に位置づけられたときにリードスクリュー５００５の作用によってそれらの対応位置で所望の処理が行えるように構成されているが、周知のタイミングで所望の動作を行うようにすれば、本例にはいずれも適用できる。
【０１２９】
また、カートリッジタイプの記録ヘッド，インクタンク一体型のものを用いたインクジェット記録装置を説明してきたが、インクンタクから記録ヘッドまで非常に細い管でインクが供給されるタイプのインクジェット記録装置も本発明に包含されるものである。
【０１３０】
図２１は、本発明のインクジェット記録ヘッドを適用したインク吐出記録を動作させるための装置全体のブロック図である。
【０１３１】
記録装置は、ホストコンピュータ３００より印字情報を制御信号として受ける。印字情報は印字装置内部の入力インタフェイス３０１に一時保存されると同時に、記録装置内で処理可能なデータに変換され、ヘッド駆動信号供給手段を兼ねるＣＰＵ３０２に入力される。ＣＰＵ３０２はＲＯＭ３０３に保存されている制御プログラムに基づき、前記ＣＰＵ３０２に入力されたデータをＲＡＭ３０４等の周辺ユニットを用いて処理し、印字するデータ（画像データ）に変換する。
【０１３２】
またＣＰＵ３０２は前記画像データを記録用紙上の適当な位置に記録するために、画像データに同期して記録用紙および記録ヘッドを移動する駆動用モータを駆動するための駆動データを作る。画像データおよびモータ駆動データは、各々ヘッドドライバ３０７と、モータドライバ３０５を介し、ヘッド２００および駆動モータ３０６に伝達され、それぞれ制御されたタイミングで駆動され画像を形成する。
【０１３３】
上述のような記録装置に適用でき、インク等の液体の付与が行われる被記録媒体としては、各種の紙やＯＨＰシート、コンパクトディスクや装飾板等に用いられるプラスチック材、布帛、アルミニュウムや銅等の金属材、牛皮、豚皮、人工皮革等の皮革材、木、合板等の木材、竹材、タイル等のセラミックス材、スポンジ等の三次元構造体等を対象とすることができる。
【０１３４】
また上述の記録装置として、各種の紙やＯＨＰシート等に対して記録を行うプリンタ装置、コンパクトディスク等のプラスチック材に記録を行うプラスチック用記録装置、金属板に記録を行う金属用記録装置、皮革に記録を行う皮革用記録装置、木材に記録を行う木材用記録装置、セラミックス材に記録を行うセラミックス用記録装置、スポンジ等の三次元網状構造体に対して記録を行う記録装置、又布帛に記録を行う捺染装置等をも含むものである。
【０１３５】
またこれらの液体吐出装置に用いる吐出液としては、夫々の被記録媒体や記録条件に合わせた液体を用いればよい。
【０１３６】
＜記録システム＞
次に、本発明のインクジェット記録ヘッドを記録ヘッドとして用い被記録媒体に対して記録を行う、インクジェット記録システムの一例を説明する。
【０１３７】
図２２は、前述した本発明のインクジェット記録ヘッド２０１を用いたインクジェット記録システムの構成を説明するための模式図である。本実施例におけるインクジェット記録ヘッドは、被記録媒体１５０の記録可能幅に対応した長さに３６０ｄｐｉの間隔で吐出口を複数配したフルライン型のヘッドであり、イエロー（Ｙ），マゼンタ（Ｍ），シアン（Ｃ），ブラック（Ｂｋ）の４色に対応した４つのヘッドをホルダ２０２によりＸ方向に所定の間隔を持って互いに平行に固定支持されている。
【０１３８】
これらのヘッドに対してそれぞれ駆動信号供給手段を構成するヘッドドライバ３０７から信号が供給され、この信号に基づいて各ヘッドの駆動が成される。
【０１３９】
各ヘッドには、吐出液としてＹ，Ｍ，Ｃ，Ｂｋの４色のインクがそれぞれ２０４ａ〜２０４ｄのインク容器から供給されている。なお、符号２０４ｅは発泡液が蓄えられた発泡液容器であり、この容器から各ヘッドに発泡液が供給される構成になっている。
【０１４０】
また、各ヘッドの下方には、内部にスポンジ等のインク吸収部材が配されたヘッドキャップ２０３ａ〜２０３ｄが設けられており、非記録時に各ヘッドの吐出口を覆うことでヘッドの保守を成すことができる。
【０１４１】
符号２０６は、先の各実施例で説明したような各種、非記録媒体を搬送するための搬送手段を構成する搬送ベルトである。搬送ベルト２０６は、各種ローラにより所定の経路に引き回されており、モータドライバ３０５に接続された駆動用ローラにより駆動される。
【０１４２】
本実施例のインクジェット記録システムにおいては、記録を行う前後に被記録媒体に対して各種の処理を行う前処理装置２５１および後処理装置２５２をそれぞれ被記録媒体搬送経路の上流と下流に設けている。
【０１４３】
前処理と後処理は、記録を行う被記録媒体の種類やインクの種類に応じて、その処理内容が異なるが、例えば、金属、プラスチック、セラミックス等の被記録媒体に対しては、前処理として、紫外線とオゾンの照射を行い、その表面を活性化することでインクの付着性の向上を図ることができる。また、プラスチック等の静電気を生じやすい被記録媒体においては、静電気によってその表面にゴミが付着しやすく、このゴミによって良好な記録が妨げられる場合がある。このため、前処理としてイオナイザ装置を用い被記録媒体の静電気を除去することで、被記録媒体からごみの除去を行うとよい。また、被記録媒体として布帛を用いる場合には、滲み防止、先着率の向上等の観点から布帛にアルカリ性物質、水溶性物質、合成高分子、水溶性金属塩、尿素およびチオ尿素から選択される物質を付与する処理を前処理として行えばよい。前処理としては、これらに限らず、被記録媒体の温度を記録に適切な温度にする処理等であってもよい。
【０１４４】
一方、後処理は、インクが付与された被記録媒体に対して熱処理、紫外線照射等によるインクの定着を促進する定着処理や、前処理で付与し未反応で残った処理剤を洗浄する処理等を行うものである。
【０１４５】
なお、本実施例では、ヘッドとしてフルラインヘッドを用いて説明したが、これに限らず、前述したような小型のヘッドを被記録媒体の幅方向に搬送して記録を行う形態のものであってもよい。
【図面の簡単な説明】
【図１】（ａ）および（ｂ）のそれぞれは、本発明によるインクジェット記録ヘッドの一実施例および比較例としての従来品のノズル部の構成を示す平面図である。
【図２】（ａ）〜（ｃ）のそれぞれは、吐出口からヒータ先端までの距離ＯＨを変数としたときの液滴の吐出量Ｖｄ、吐出速度ｖ、リフィル周波数ｆｒを示す図である。
【図３】液滴の吐出量Ｖｄと吐出速度ｖ、および吐出口面積ＳＯと吐出口からヒータ先端までの距離ＯＨとの積と距離ＯＨとの関係をともに示す図である。
【図４】吐出速度ｖを吐出量Ｖｄで除算した結果と距離ＯＨとの関係を示す図である。
【図５】本発明の一実施例にかかる記録ヘッドの主にインク路の縦断面を示す図である。
【図６】本発明の実施例を説明するための図１と同様の図である。
【図７】上記実施例を説明するための吐出ヒータ距離と吐出インク滴体積との関係を示す線図である。
【図８】ヒータ面積ＳＨを大きくしていったときの曲線曲線曲線ａ，ｂ の変化を示す図である。
【図９】（Ａ）〜（Ｄ）は、上記実施例と従来例とを比較しながら吐出時のリフィルの挙動を説明するためのインク路の断面図である。
【図１０】比例係数ＳＯ’の変化を示す図である。
【図１１】（ａ）〜（ｃ）のそれぞれは、２つのヒータの重心位置と吐出口間の距離ＯＰを変数とすると、吐出量Ｖｄ、吐出速度Ｖおよびリフィル周波数ｆｒ等の吐出特性を示す図である。
【図１２】本発明によるインクジェット記録ヘッドの特性測定において使用したノズルおよびヒータの形状を示す図である。
【図１３】後ろ側ヒータの距離ＯＨを固定とし、前側ヒータの位置を変化させたときの吐出特性示す図であり、（ａ）は吐出速度ｖ、（ｂ）は吐出量Ｖｄ、（ｃ）は吐出速度ｖを吐出量Ｖｄで除いた値であり、これらはともに前側ヒータのみを用いた場合と前側ヒータおよび後ろ側ヒータを同時に用いた場合が示さている。（ｄ）は各場合の位置ずれ量を示している。
【図１４】後ろ側ヒータの距離ＯＨを固定とし、前側ヒータの位置を変化させたときの吐出特性示す図であり、（ａ）は吐出速度ｖ、（ｂ）は吐出量Ｖｄ、（ｃ）は吐出速度ｖを吐出量Ｖｄで除いた値であり、これらはともに前側ヒータのみを用いた場合と前側ヒータおよび後ろ側ヒータを同時に用いた場合が示さている。（ｄ）は各場合の位置ずれ量を示している。
【図１５】（ａ），（ｂ）のそれぞれは、本発明の第２の実施例を説明するための図で、ほぼ同じインク滴を吐出するノズル１００１，１００５の構成を示す平面図である。
【図１６】本発明によるインクジェット記録カートリッジの一例を示す図である。
【図１７】本発明の実施形態を説明するための図である。
【図１８】インクジェット記録ヘッドを用いたインクジェットヘッドカートリッジの一例を示す分解斜視図である。
【図１９】インクジェットヘッドカートリッジの模式的斜視図である。
【図２０】インクジェット記録装置ＩＪＲＡの概観図である。
【図２１】装置全体のブロック図である。
【図２２】インクジェット記録システムの構成を説明するための模式図である。
【符号の説明】
１０１，１０５ ノズル
１０２，１０３，１０６ ヒータ
１０４，１０７ 吐出口[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention,An inkjet recording head having a plurality of electrothermal transducers in one flow path (nozzle)TheThe present invention relates to an inkjet recording apparatus used.
[0002]
[Prior art]
Most of ink jet recording apparatuses are used as printing apparatuses in printers, facsimile machines, word processor copiers, etc., and among them, heat energy is used as energy used for ink ejection, and ink is ejected by bubbles generated thereby. Has recently become widespread.
[0003]
Further, as another application of the ink jet recording apparatus of this type, an ink jet textile printing apparatus for printing a fixed pattern, a picture, or a composite image on a cloth has recently been known. An ink jet recording head used in an ink jet recording apparatus as described above uses an electrothermal conversion element (hereinafter, also referred to as a "heater") to generate thermal energy. And a configuration having one heater. On the other hand, an apparatus provided with a plurality of heaters for one discharge port is conventionally known from the viewpoints described below.
[0004]
In other words, first, a plurality of heaters are driven alternately or one by one in order to extend the life of the inkjet recording head. Second, a plurality of heaters are used for the purpose of increasing the range in which the ink ejection amount is changed. In such a case, the ejection amount is changed by selecting a heater to be driven and the number thereof.
[0005]
As a more specific configuration of the latter, a plurality of heaters are arranged in the ink discharge direction in the ink flow path communicating with the discharge port of the ink jet recording head, and the heater to be driven (heated) or the heater of the heater is provided. It is known that by selecting the number, the distance between the discharge port and the driven heater is made different, thereby changing the discharge amount.
[0006]
As another configuration, for example, as disclosed in Japanese Patent Application Laid-Open No. 55-132259, a plurality of heaters having different surface areas are arranged in the ink flow path, and the heaters or the number of heaters that are driven in the same manner are changed. It is known that the ink ejection amount is made variable by changing the amount of ink.
[0007]
[Problems to be solved by the invention]
However, there are some problems in realizing an ink jet recording apparatus that makes the ejection amount variable.
[0008]
One problem is that when an ink droplet having a small ejection amount is ejected, the ejection power is small, that is, since the ink is foamed by a heater having a small heater area, not only the ejection amount but also the ejection speed is reduced. This is a particularly serious problem in so-called preliminary ejection performed as part of the ejection recovery process.
[0009]
Preliminary ejection is generally performed when the apparatus is in a predetermined state, and ejects ink that is not involved in recording from the inkjet recording head, thereby removing thickened ink and the like in the inkjet recording head. As a result, the ink ejection state can be kept good. Such preliminary ejection is usually performed at regular time intervals immediately after the power of the apparatus is turned on or during printing.
[0010]
However, when the ink can be ejected at various ejection amounts by a plurality of heaters as described above, it is necessary to shorten the preliminary ejection interval when performing printing with a small ejection amount setting. That is, since the power of the small ejection ink droplet is small, there is a possibility that the thickened ink may not be able to be stably ejected depending on the degree of thickening of the ink due to the evaporation of the water at the ejection port. For this reason, it is necessary to frequently perform the preliminary ejection, and in particular, it is necessary to shorten the interval of the preliminary ejection performed at a certain time interval during printing, and there is a problem that the printing throughput is reduced.
[0011]
Further, when the ejection speed of the ink droplets is low, the degree of elasticity of the recording medium on the recording medium may decrease due to a slight change in the ejection direction from the ejection port, which may adversely affect the image quality.
[0012]
Further, conventionally, it has been known that the ejection speed is substantially proportional to the ejection amount, and the difference between the ejection speed at the large ejection amount and the ejection speed at the small ejection amount is large. When an image is formed with such an ink jet recording head, the landing positions of large dots and small dots formed by large and small discharge droplets are shifted due to a difference in discharge speed, so that image deterioration may occur. Danger increases.
[0013]
The conventional example has the following problems in addition to the above-mentioned problems.
[0014]
When printing with a small ejection amount, the image data amount increases due to the high resolution, and the number of recording dots increases.To maintain or increase the recording speed, the ejection repetition frequency must be increased. However, it is very difficult depending on the type of ink used.
[0015]
It is also important that the repetition frequency at a large discharge rate is high. This is because, even if the printing speed of the small ejection amount is increased, the printing apparatus will be down-specified if the printing speed of the conventional ejection amount is decreased.
[0016]
From another viewpoint, it is also important to have commonality with the conventional type. This is because, for example, an ink jet recording head having a certain discharge amount is used as a replaceable type. In order to improve the function of the recording device, it is assumed that not only a large ejection amount but also a small ejection amount of ink droplets are ejected by the same inkjet recording head, and if there is no commonality with the conventional type, the conventional In order to increase the number of production lines, conventional inkjet printheads and new inkjet printheads that eject large and small ink droplets must be manufactured in parallel for users of existing recording devices. As a result, there is a problem that the manufacturing cost increases.
[0017]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional technology, and has been made in consideration of the above-described problems. Inkjet printhead that has a single heater corresponding to the outlet, can print high-quality images at high speed, and can be used for conventional printing apparatuses.Inkjet recording device usingThe purpose is to realize.
[0018]
Other objects of the present invention can be inferred from the contents of the embodiments.
[0019]
To achieve the above purposeThe present inventionIncludes a plurality of liquid flow paths having discharge ports for discharging ink, and a plurality of electrothermal conversion elements disposed in each liquid flow path and generating thermal energy for discharging ink. One head,
A plurality of liquid flow paths having discharge ports for discharging ink, and provided in parallel with respect to each liquid flow pathThe shape is different from the plurality of electrothermal transducers of the first headA second head including a plurality of electrothermal conversion elements, and an ink jet recording apparatus that is used by exchanging, and ejects ink.
The distance from the center of gravity of the plurality of electrothermal conversion elements to the discharge port in each liquid flow path of the first head, and the distance from the center of gravity of the plurality of electrothermal conversion elements to the discharge port in each liquid flow path of the second head. And are substantially the same.
[0020]
Also, the present invention provides a plurality of liquid flow paths having discharge ports for discharging ink, and one electrothermal conversion element disposed in each liquid flow path and generating thermal energy for discharging ink. A first head including:
A second head including a plurality of liquid flow paths having discharge ports for discharging ink and a plurality of electrothermal transducers provided in parallel with respect to each liquid flow path is used by exchanging ink. An inkjet recording apparatus that performs
The distance from the center of gravity of the electrothermal conversion element in each liquid flow path of the first head to the discharge port and the distance from the center of gravity of both electrothermal conversion elements in each liquid flow path of the second head to the discharge port are: It is characterized by being substantially the same.
[0038]
"Action"
The discharge amount Vd of the ink droplet has a maximum value when the distance OH from the discharge port side end of the electrothermal transducer to the discharge port is a predetermined distance, and decreases as the distance from the predetermined distance OH decreases. In addition, the ejection speed v increases as the distance OH decreases, and the refill frequency fr decreases as the distance OH decreases, contrary to the ejection speed v.
[0039]
According to the present invention, by arranging the electrothermal transducer as described above based on the above-described characteristics, when discharging large and small droplets, the discharge amount, the discharge speed and the refill frequency are satisfied. It has become something.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0041]
Next, examples of the present invention will be described.
[0042]
<Head structure>
FIGS. 1A and 1B are plan views showing the configuration of a conventional nozzle section as an embodiment and a comparative example of an ink jet recording head according to the present invention.
[0043]
This embodiment shows an edge chute type configuration in which liquid is discharged in a direction substantially perpendicular to the surface on which the heating element is formed, and the nozzle 101 has an array density of 360 dpi. In the nozzle 101, two heaters 102 and 103 having substantially the same size and the same length are arranged side by side so that the distance from the discharge port 104 to each heater is different. In the comparative example shown in FIG. 1B, the arrangement density of the nozzles 105 is the same as that in the embodiment shown in FIG. 1A, but only one heater 106 is provided in the nozzle 105.
[0044]
In the following description, the distance from the discharge port 104 to each heater 102, 103 in the embodiment shown in FIG. 1A is OH1, OH2, and the distance from the discharge port 104 to the center of gravity (center) of each heater 102, 103. Are OP1 and OP2, and the center of gravity when these two heaters 102 and 103 are viewed as one heater is OP = (OP1 + OP2) / 2. 1B, the distance from the discharge port 107 to the heater 106 in the comparative example is OH, and the distance from the discharge port 107 to the center of gravity of the heater 106 is OC.
[0045]
As will be described in detail later, the two heaters are configured to be able to be driven independently of each other, and in this case, the ejection amount of the small droplet is set to about 20 pl. By driving the two heaters simultaneously, a large droplet having a discharge amount of about 40 pl, which is about twice the discharge amount of either one, is discharged.
[0046]
Next, the ejection characteristics of the ink jet recording head according to this embodiment will be described with reference to FIG. Each of FIGS. 2A to 2C is a diagram showing a discharge amount Vd of a droplet, a discharge speed v, and a refill frequency fr when the distance OH from the discharge port to the tip of the heater is used as a variable. It shows the following trends.
[0047]
The ejection amount Vd of the ink droplet is set to a maximum value at a certain predetermined distance OH indicated by a dashed line in FIG. 2A, and decreases as the distance from the predetermined distance OH increases.
[0048]
The discharge speed v increases as the distance OH decreases, as shown in FIG.
[0049]
As shown in FIG. 2C, the refill frequency fr decreases as the distance OH decreases, contrary to the ejection speed v.
[0050]
2 (b) and 2 (c) show the ejection speed v and the refill frequency fr for two heater areas, and any of these parameters shifts according to the size of the ejection area SH.
[0051]
FIG. 3 is a diagram showing both the relationship between the discharge amount Vd of the droplet and the discharge speed v, the product of the discharge port area SO and the distance OH from the discharge port to the tip of the heater, and the distance OH. FIG. 4 is a diagram showing a relationship between a result obtained by dividing a discharge speed v by a discharge amount Vd and a distance OH. 3 and 4, the singular points a and b are defined from a viewpoint different from the predetermined distance OH as described above, and the distance OH is defined as an area A equal to or more than a, an area B equal to or less than b, and a and b. Are divided into three regions, that is, a region C between them.
[0052]
The characteristic tendency of each region is that, in the region A, the discharge speed v and the discharge amount Vd are substantially proportional to the increase in the distance OH, and v / Vd is substantially constant. Further, in the region B, the ejection amount Vd is substantially proportional to the product of the ejection opening area SO and the distance OH, and in the region C, the ejection amount Vd is substantially constant.
[0053]
In addition, the above-described areas A to C can be defined as follows by considering each of the ejection amount Vd and the ejection speed v.
[0054]
<When viewed from the discharge amount Vd>
Area A: a section in which the discharge amount Vd decreases as the distance OH increases.
Area B: a section that increases almost in proportion to the ejection amount Vd and the distance OH
Area C: a section where the discharge amount Vd is substantially constant with respect to the distance OH.
<When viewed from the discharge speed v>
The discharge speed v decreases with an increase in the distance OH over all the sections, but particularly in the region C, the change amount becomes gentle.
[0055]
Based on the above-described discharge amount characteristics and refill frequency characteristics, a mechanism in which the regions shown in FIGS.
[0056]
Assuming that the heater is fixed, the ink droplet speed v and the ejection amount Vd greatly depend on the (inertia) resistance on the ejection port side from the heater of the nozzle and the (inertia) resistance behind the heater, and The amount Vd is determined from the relationship that the product does not greatly exceed the product of the discharge port area SO and the distance OH from the discharge port to the heater tip.
[0057]
A region (second region) in FIG. 3 has a relationship of SO '× OH <Vd (SO' is a proportional constant). In other words, this is an area where the velocity v and the discharge amount Vd are determined by the balance between the (inertia) resistance behind (liquid chamber side) and the front (discharge port side) of the heater. Let F and R be the areas where the ejection speed v and the ejection amount Vd are substantially proportional to R / (F + R). Therefore, when the distance OH is increased, the inertial resistance in front of the heater increases. On the other hand, since the inertial resistance behind the heater is reduced, the force on the ejection port side is weakened, and the speed and amount of ink moving to the ejection port side are reduced. This will be described in more detail.
[0058]
FIG. 5 is a diagram showing a cross-sectional configuration of an ink flow path of a general inkjet recording head.
[0059]
The ink path 401 is formed by joining the top plate 413 with the ink path groove formed thereon and the heater board 403, and the ink path 401 is communicated with the common liquid chamber 407 and is filled with the ink 406. A heater 404 for generating thermal energy for discharging ink is formed on the heater board 403, thereby heating the ink 406 in the ink path 401 to generate bubbles by vaporization. In the stationary state, the ink 406 forms a meniscus at a certain position near the orifice due to the balance between the negative pressure in the ink tank (not shown) and the capillary force (flow path resistance) in the ink path 401. I have. When the driving power is supplied to the heater 404 to form bubbles, the ink 406 in the ink path 401 in front of the heater 404 is ejected as droplets by the pressure due to the change in the volume of the bubbles. Thereafter, the meniscus of the ink 406 remaining in the ink path 401 in front of the heater 404 retreats to return to the heater portion.
[0060]
In FIG. 5, when the ink flow resistance (inertia resistance) on the orifice side from the center of the heater 4 is F, the following equation can be obtained: F = heater center to orifice distance / ink path cross-sectional area. Further, if the ink flow resistance on the common liquid chamber 7 side from the center of the heater 4 is R, R = distance from the center of the heater to the liquid chamber / ink path cross-sectional area.
[0061]
Now, it is considered that the ink 406 is heated by the heater 404 to generate a bubble 408 as shown in FIG. 6 and eject the ink droplet 409 from the orifice 405. At this time, the volume Vd of the ink droplet 409 is substantially expressed by the following equation (1), where Vb is the maximum volume of the bubble 408.
[0062]
Vb = (R / (F + R)) · Vb (1)
Where Vb∝SH (heater size)
The following is clear from equation (1).
[0063]
The discharge volume Vd decreases as F increases, that is, as the distance OH (see FIG. 5) from the front end of the heater 404 to the orifice 405 increases. This relationship is shown by curve a in FIG.
[0064]
On the other hand, the area B (first area) is an area where Vd ≒ SO ’× OH. When the distance OH is short, the inertia resistance in front of the heater is small, so that the speed v is large. However, the bubbling bubbles on the heater become obstacles to the flow of ink toward the ejection port side in the nozzle, and the flow is interrupted. As a result, the ejection amount Vd is not reduced in proportion to the ejection speed v. It is inferred. In short, it is conceivable that a state in which ink is not supplied may occur even though the applied power is expected to be a larger ejection amount Vd. That is, it is considered that a limited discharge amount Vdlim formed by the discharge port area SO and the distance OH from the discharge port to the heater end can be obtained. This relationship is expressed by the following equation (2).
[0065]
Vdlim = SO · OH (2)
The relationship of the above equation (2) is shown by a curve b in FIG.
[0066]
FIG. 8 shows an approximate relationship between the discharge amount Vd and the distance OH, and is a diagram showing a change in the curves a and b when the heater area SH is changed. As is apparent from the figure, the curves a and b shift according to the size of the heater area SH.
[0067]
Here, let L be the distance between points where the two curves a and b shown in FIG. 7 intersect. Basically, a region where Vd> Vdlim is satisfied at the boundary of OH = L is a region B, and a region where Vd <Vdlim is satisfied. A region. The process of foaming → defoaming → refilling the meniscus will be described below with reference to FIG.
[0068]
When bubbles 408 are generated by heating by the heater 404 at time t1 (FIG. 9A), the state shown in FIG. 9B is obtained at time t2.
[0069]
As shown in FIG. 9C, the bubble 408 disappears at time t3.
[0070]
The principle of the defoaming will be described with reference to FIG.
[0071]
The retreat volume VMe of the meniscus 411 (the volume that becomes blank) is Vb, the maximum volume of the bubble 408 is Vb, the fluid resistance on the orifice 405 side of the bubble 408 is F ′ (see FIG. 6), and the liquid chamber side is R ′ (see FIG. 6). )
VMe = (R '/ F' + R '). Vb = (R' / F '+ R'). (F + R) / R) .Vd
Indicated by In other words, when defoaming, considering that ink moves from the orifice 405 side and the liquid chamber 407 side to fill the defoaming bubble, respectively, as shown in the area A (the distance OH is If F ′ is large (because it is relatively large), the resistance on the orifice 405 side becomes large, and the amount of ink movement from the liquid chamber 407 becomes relatively large. As a result, the defoaming position 410 does not move backward, so that the retreat amount (VMe) of the meniscus is reduced. This is advantageous for refilling.
[0072]
On the other hand, when F ′ is small (because the distance OH is small) as in the area B, the ink movement from the meniscus 409 side becomes large, and the defoaming position 410 shifts backward. As a result, the meniscus retreat amount is smaller than the ejection amount. It becomes big. Therefore, the refill time becomes longer.
[0073]
As described above, in the region A, the amount of meniscus retreat is small, and the refill frequency fr is high. On the other hand, in the region B, the meniscus retreat amount is large and the refill frequency fr is low.
[0074]
As described above, the area A and the area B are distinguished from each other based on the distance OH at which the ejection amount Vd has a maximum value when the distance OH is a variable. As a result of the experiment using the head of this embodiment, A close look at the vicinity of the value shows that the ejection amount Vd is a very gentle curve that is almost constant with respect to the distance OH.
[0075]
This is presumed to be at least partly because foamed bubbles on the heater are not completely obstructed by the flow of ink toward the discharge ports in the nozzles.
[0076]
That is, since the heaters are arranged substantially in parallel between the nozzles, the front heater does not block the entire nozzle flow path and does not completely block the flow of ink, so that ink can be supplied from the side of the front heater. It is thought to be from.
[0077]
Inferring from another point of view, it takes a certain time until the droplet is completed, so if some ink protrudes from the tip of the discharge port at the initial stage of discharge, the inertial resistance on the front side of the heater will decrease. The viscous resistance becomes dominant and the flow of ink in the nozzles slows down. In particular, when the distance OH is shortened, the above effect is not obtained, and the ejection amount Vd may gradually decrease. It is thought that there is not. In any case, in this region, the ejection amount Vd is stable irrespective of the value of the distance OH, so that it can be said that the ejection amount Vd is also stable against variations in head manufacturing. Further, since the distance OH is relatively long, the refill frequency fr also has a relatively good value.
[0078]
In a conventional ink jet recording head having a large discharge amount provided with one discharge heater in one nozzle, the discharge amount Vd is smaller than a predetermined distance OH indicated by a dashed line in FIG. When OH was used as a variable, the experimental result was almost equal to the proportional relationship in which the proportional coefficient SO ′ was approximately SO.
[0079]
However, this time, when an experiment was performed by changing the heater area so as to reduce the heater width, the proportional coefficient SO ′ increased as the heater width increased as shown in FIG. I found it to be.
[0080]
That is, when the heater width is small, the proportional coefficient SO 'has a smaller value than the discharge port area SO. Here, assuming that the proportional coefficient SO 'is the effective discharge port area, it can be considered that the effective discharge port area decreases as the heater width decreases. Here, it is assumed that SO ′ on the vertical axis of FIG. 10 is an effective discharge port, and the discharge port diameter 2 (SO ′ / π) in that case is assumed.^1/2Were made to correspond.
[0081]
Based on the knowledge described above, in the ink jet recording head of this embodiment, the size of the heater width of one heater (the front heater (the discharge port side is defined as the front side)) is compared with the effective discharge port area of SO. And the distance OH is set as the heater position so that the distance OH is in the area B (or the area C (the second area)), and the other heater (the rear heater) is set. The heaters were arranged so that the distance OH was substantially the same size as the front heater and the distance OH was in the area A (or area C).
[0082]
The driving method was set so that the discharge amounts when driven independently by the respective heaters were substantially equal, and when both were driven simultaneously, the discharge amount was doubled. When the discharge amount ratio of the large and small droplets is set to 2: 1 in this manner, the driving method is facilitated by setting the distance OH of each heater to be symmetrical with respect to the distance to be a bending point, Such an arrangement is desirable.
[0083]
Here, a small dot is ejected by the front heater, and a large dot is ejected by simultaneously driving the front and rear heaters to increase the ejection speed of the small dot, and the difference (or ratio) between the ejection speeds of the large and small dots. Could be reduced. Further, if the distance OH of the front heater is too short, the refill frequency fr becomes low although the ejection speed v becomes large, so that the distance OH may be set within a range that can satisfy the drive frequency.
[0084]
Next, a preferred position of the heater for discharging large dots will be described.
[0085]
As described above, the large dot is ejected by driving the front and rear heaters. Assuming that the distance OP between the center of gravity of the two heaters and the ejection port is a variable, the ejection amount Vd, ejection speed V, and refill The ejection characteristics such as the frequency fr are as shown in FIGS. In the example shown in FIG. 11, the distance OH1 of the front heater is fixed, and the distance OP obtained by changing the distance OH2 of the rear heater is used as a variable.
[0086]
It is known that the discharge amount Vd in the above case is substantially equal to the sum of the discharge amounts when the front heater and the rear heater are independently driven, and the discharge amount Vd becomes maximum when the distance OP is a predetermined distance. . In the present embodiment, the distance OP is set to a value larger than the predetermined distance.
[0087]
From FIGS. 11B and 11C, it can be seen that if the distance OP is too short, the ejection speed v becomes too fast, the speed difference between large and small dots becomes large, and the refill frequency becomes low. Here, a case is considered where only one heater is disposed in the nozzle as shown in FIG. An experiment was conducted in which the size of only one heater was set so that the two heaters of the present embodiment were combined into one, and the distance OC between the center of gravity and the discharge port was OC = OP. However, a discharge amount Vd, a discharge speed v, and a refill frequency fr substantially similar to those of the present embodiment were obtained.
[0088]
From the above experimental results, considering the commonality with the conventional inkjet recording head, the droplet ejection amount Vd, the ejection speed v, and the refill frequency fr are substantially equal by making the OP and OC of the conventional product substantially equal. It can be understood that it can be. If the distance OH1 to the front heater is set too small to improve the ejection speed v, the distance OH2 to the rear heater needs to be increased. However, the distance OH2 becomes longer than necessary to make OC ≒ OP. Then, there is a possibility that the generated air bubbles may penetrate to the rear where the supply system for supplying the ink to the nozzles is provided. Therefore, it is preferable to set OP <OC in order to prevent this.
[0089]
In addition, in the case of a large dot, if the distance OH is in the area B, the ejection stability deteriorates. Therefore, even if the commonality with the conventional product is not assumed, the distance OC is set such that the distance OH is in the area A. It is desirable to set to.
[0090]
An ink jet recording head in which a heater was arranged was manufactured based on the above setting conditions, and the characteristics were measured. The results are shown below.
[0091]
Measurement 1
FIG. 12 shows the shapes of the nozzle and the heater used in the measurement. The nozzle 104 communicates with the liquid chamber 51, and forms a meniscus 52 near the orifice 40 by capillary force in the nozzle. Although there are at least two or more heaters in the nozzle, the case of two heaters will be described in this figure. The total length L of the nozzle was 400 μm. An electrode is connected to each of the heaters A and B, and a common electrode is connected to terminals on opposite sides. Switching means is connected to the tip of each electrode, and can selectively drive the heaters A and B to discharge ink in the nozzles. The configuration of the two heaters is HW_A  = 22 μm, HL_A  = 135 μm, OH_A  = 100 μm and HW_B  = 24 μm, HL_B  = 135 μm, OH_B  = 160 μm, the evaluation was made on the assumption that the small droplets were formed by heating and foaming only the heater A and discharged, and the large droplets were formed by heating and foaming the heaters A and B simultaneously and discharged. The ink used had a surface tension of about 40.5 to 46.5 (dyne / cm) and a viscosity of 1.5 to 2.1 (cP). The opening area SO of the discharge port is 680 μm²And
[0092]
Table 1 showing the first measurement results is a table showing the relationship between the configuration of the heater, the ejection amount, and the ejection speed, and the amount of ink mist when ejection is performed at 6.5 KHz. From the results in the table, the ejection speed of small droplets and large droplets and the ejection amount are sufficient to perform high-quality printing, and the amount of ink mist generation is also small, so that high-quality printing can be obtained. You can see what you can do.
[0093]
[Table 1]

Measurement 2
Table 2 shows the results of the second measurement.
[0094]
The configuration of the heater is HW_A  = 21 μm, HL_A  = 136 μm, OH_A  = 100 μm and HW_B  = 19 μm, HL_B  = 137 μm, OH_B  = 140 μm. In this case as well, a result sufficient for performing high-quality printing was obtained as in the first embodiment.
[0095]
That is, even if the shape and size of the heater are changed, good results can be obtained by setting the difference in the OH distance to an appropriate value.
[0096]
[Table 2]

Measurement 3
Next, Table 3 shows the relationship between the ejection speed and the ink mist with respect to the difference in the OH distance. Table 3 (a) shows the relationship between the OH distance of heater A, the ejection speed of small droplets, and ink mist. Table 3 (a) shows the relationship between the difference in OH distance between the two heaters, the ejection speed of large droplets, and ink mist. The results are shown in Table (b). The heater size at this time was the same as that of the first embodiment in HW._A  = 22 μm, HL_A  = 135 μm and HW_B  = 24 μm, HL_B  = 135 μm.
[0097]
In Table 3 (a), when the OH distance of the heater A exceeds 120 μm, the discharge speed of the small droplet gradually decreases, and high-quality printing cannot be expected. When the thickness is 70 μm or less, the amount of ink mist increases. It is considered that this is because the refill frequency fr becomes worse and the ejection state becomes unstable.
[0098]
In Table 3 (b), the OH distance of the heater A was 100 μm, and the ejection speed of large droplets was shown with respect to the OH distance of the heater B. When the OH distance is less than 110 μm, ink mist is generated at the time of discharging a large droplet, the discharging direction is bent, and the droplet landing accuracy is reduced. Further, when the OH distance was 200 μm or more, non-discharge occurred occasionally.
[0099]
Therefore, in order to increase the ejection speed of small droplets, suppress the generation of ink mist at the time of ejecting large droplets, and perform stable ejection, the OH distance of the heater for ejecting small droplets must be set to 80. １３０130 μm, and the difference between the OH distances of the two heaters may be 10-80 μm. If higher quality recording is required, the difference between the OH distances may be set to 20 to 60 μm.
[0100]
[Table 3]

Measurement 4
Next, the distance OH of the rear heater was fixed at 170 μm, and the discharge characteristics when the position of the front heater was changed were measured. The measurement was carried out for those having different discharge port areas SO and front heater and rear heater areas SH. The results are shown in Tables 4 and 5, and graphs of these are shown in FIGS. 13 and 14. 13 and 14, (a) shows the discharge speed v, (b) shows the discharge amount Vd, and (c) shows the value obtained by removing the discharge speed v by the discharge amount Vd. Both of them use only the front heater. The case and the case where the front heater and the rear heater are used at the same time are shown. (D) shows the amount of displacement in each case.
[0101]
In the measurement in which the measurement results are shown in Table 4, the discharge port area SO is 380 μm²Each of the front heater and the rear heater had an area SH of 17 μm × 135 μm. In the measurement in which the measurement results are shown in Table 5, the discharge port area SO is 400 μm²The area SH of the front heater was 17 μm × 115 μm, and the area SH of the rear heater was 23 μm × 115 μm. In each measurement, the ink used had a surface tension of about 26.0 to 37.0 (dyne / cm) and a viscosity of 1.85 to 2.60 (cP). The ejection speeds vF and vF + B and the ejection amounts VdF and VdF + B at the time of dot ejection are measured, and the inkjet recording head having the above configuration is mounted on a carriage having a scanning speed of 0.7 (m / s). The recording flight time and landing position deviation when mounted on a recording apparatus having a distance to the recording medium of 1 mm are obtained, and a first value obtained by dividing the ejection speed at the time of ejection of small dots by the ejection amount, and a large dot A second value obtained by dividing the ejection speed at the time of ejection by the ejection amount is obtained, and a value obtained by dividing the first value by the second value is obtained.
[0102]
[Table 4]

[0103]
[Table 5]

From the above measurement results, when the first value is larger than the value obtained by multiplying the second value by the proportional coefficient 1.15, that is, the discharge speeds vF, vF + B and the discharge amounts VdF, VdF + B are:
(VF / VdF) ≧ (vF + B / VdF + B) × C
(C is a constant)
It has been found that by arranging such that the relationship is satisfied, preferable ejection speed, ejection amount ratio, landing position deviation amount, and refill frequency can be obtained. The constant C varies depending on the physical properties of the ink and the like. According to the experiments performed by the present inventors, the surface tension is about 26.0 to 37.0 (dyne / cm), and the viscosity is 1.85 to 2.60 (cP). When the ink of No. was used, C = 1.15, the surface tension was about 40.5 to 46.5 (dyne / cm), and the ink having a viscosity of 1.5 to 2.1 (cP) was used. Sometimes it was found that C = 1.0.
[0104]
Next, a second embodiment of the present invention will be described. This embodiment relates to the shape and the position of the center of gravity of the heater.
[0105]
In order to obtain a predetermined ink droplet volume in an ink jet recording apparatus that heats a heater to foam ink on the ink and discharge ink droplets, a heater having a predetermined area is required.
[0106]
In order to increase the density of the nozzles, it is necessary to reduce the width of the heater. However, at this time, the heater area must be equal in order to obtain the same ink droplet volume as the heater having a large width. The length will be increased. When a plurality of heaters are arranged in the nozzle row direction in one nozzle, the width is further reduced and the heater length is further increased.
[0107]
FIGS. 15A and 15B are views for explaining the second embodiment in consideration of the above characteristics, and are plan views showing the configurations of the nozzles 1001 and 1005 that discharge substantially the same ink droplets. FIG. 9 is a diagram for explaining that characteristics are different depending on a heater shape.
[0108]
Two heaters 1002 and 1003 are provided in the nozzle 1001, and heaters 1006 and 1008 are provided in a nozzle 1005 having the same shape as the nozzle 1001. The heaters 1002 (1003) have a smaller width and a longer length than the heaters 1006 (1008), but have substantially the same area, and are arranged so that the center of gravity of each heater with respect to the nozzles 1001 and 1005 is equal. Have been. By arranging under such conditions, the distance OC1 from the ejection port 1004 of the nozzle 1001 shown in FIG. 15A to the front heater 1002 is changed from the ejection port 1007 of the nozzle 1005 shown in FIG. It will be shorter than the distance OC2 to 1006. As a result, the end of the heater 1002 is located in the region B, and the discharge amount Vd is reduced. Further, the distance from the ejection port 1004, which is the center of foaming, to the center of gravity is the same as that shown in FIG. 15B, which is wide, and the center of gravity of each heater is in the A region. These are almost the same, and both the formation of small droplets and the efficient refilling can be achieved.
[0109]
Next, a third embodiment of the present invention will be described.
[0110]
In the present embodiment, the branch point of the A region, the B region and the C region other than the A region is defined as 130 μm from the contents shown in FIG. 4, and the ejection speed vF is determined from each measurement result in accordance with the type of ink. , VF + B and the discharge amount VdF, VdF + B.
[0111]
Each of these parameters is described and defined below.
[0112]
When an ink having a surface tension of about 26.0 to 37.0 (dyne / cm) and a viscosity of 1.85 to 2.60 (cP) is used,
vF ≧ 8 (m / S)
vF + B ≦ 16 (m / S)
VdF ≦ 25 (pl)
35 ≦ VdF + B ≦ 45 (pl)
It is assumed that the following relationship is satisfied.
[0113]
When an ink having a surface tension of about 40.5 to 46.5 (dyne / cm) and a viscosity of 1.5 to 2.1 (cP) is used,
vF ≧ 7.5 (m / S)
vF + B ≦ 16 (m / S)
VdF ≦ 40 (pl)
65 ≦ VdF + B ≦ 80 (pl)
It is assumed that the following relationship is satisfied. Under the above conditions, large and small discharges can be performed satisfactorily.
[0114]
FIG. 16 shows a combination of inkjet head cartridges A to D using an inkjet recording head having the above-described characteristics. Y (yellow), M (magenta), C (cyan), and Bk (black) are supplied to the inkjet head cartridges A to D for color recording. Here, as the ink jet recording heads constituting the ink jet head cartridges A to C, those having the above constant C of 1.15 are used, and those of the ink jet head cartridge D having the above constant C of 1.00 are used. It is used.
[0115]
As an embodiment of each of the above-described embodiments, in the example shown in FIG. 17A, two heaters having the same shape are arranged so as to be adjacent to each other, and as shown in FIG. Both heaters are arranged so as not to be adjacent to each other, heaters having different shapes are arranged so as to be adjacent to each other as shown in FIG. 17C, and different heaters are arranged as shown in FIG. All the heaters arranged so that they are not adjacent to each other are included.
[0116]
In each of the above-described embodiments, an example in which two heaters are provided has been described. However, the concept of the present invention can be applied to a case where more heaters are provided. For example, when a plurality of heaters are arranged side by side at one location, these may be regarded as one heater and the present invention may be applied to the center of gravity. Further, when the distances OH are provided so as to be different from each other, the present invention may be applied to the center of gravity of a heater having a front-back relationship as one heater.
In addition, by combining the above-described embodiments, the effects of the respective embodiments are synergistic, and such a configuration may be adopted.
[0117]
FIG. 18 is an exploded perspective view showing an example of an ink jet head cartridge using the ink jet recording head configured as described above.
[0118]
In FIG. 18, a recording head unit IJU is a unit of a type that discharges ink by generating thermal energy according to an electric signal to cause film boiling of ink. The heater board 100 includes, on a Si substrate, electrothermal transducers (discharge heaters) for generating the thermal energy, which are arranged in a plurality of rows, and electric wiring such as Al for supplying power thereto. The wiring substrate 200 formed by the film technology includes a wiring corresponding to the wiring of the heater board 100 (for example, connected by wire bonding) and a pad located at an end of the wiring and receiving an electric signal from the main body device. 201. The top plate 1300 includes a partition for forming an ink path, a common liquid chamber, and the like corresponding to each of the plurality of ink ejection ports, and also receives ink supplied from the ink tank and introduces the ink into the common liquid chamber. And an orifice plate 400 having a plurality of ejection ports. The partition walls and the like provided on the top plate 1300 are formed integrally with the top plate 1300. As the integrally formed material, polysulfone is preferable, but another resin material for molding may be used.
[0119]
The support 300 supports the rear surface of the wiring substrate 200 on a flat surface, and is formed of, for example, metal, and forms a structural member of the recording head unit. The presser spring 500 has an M-shape, and presses a portion corresponding to the common liquid chamber of the top plate 1300 at the center of the M shape, and also linearly connects a portion corresponding to the ink path of the top plate 1300 with the front droop 501. Press by contact. The foot of the presser spring 500 is engaged with the back side of the support 300 through the hole 3121 of the support 300, so that the heater board 100 and the top plate 1300 are sandwiched between the support board 300 and the heater board 100. Accordingly, the heater board 100 and the top plate 1300 can be pressed and fixed to the support 300 by the urging force of the presser spring 500 and the front sag 501. The support body 300 has two positioning holes 312 and 1900 that respectively engage with the two positioning protrusions 1012 and the two positioning and heat fusion holding protrusions 1800 provided on the ink tank. Protrusions 2500 and 2600 for positioning the cartridge with respect to the carriage on the apparatus main assembly side are provided on the back side. In addition, the support 300 also has a hole 320 that can penetrate an ink supply pipe 2200 (described later) that allows ink to be supplied from the ink tank. The attachment of the wiring board 200 to the support 300 is performed by sticking with an adhesive or the like.
[0120]
The concave portions 2400, 2400 of the support 300 are provided near the positioning projections 2500, 2600, respectively. These concave portions are provided in the assembled head cartridge (shown in FIG. 19) in the recording head of the head cartridge. At the extension points of the plurality of parallel grooves 3000 and 3001 formed on the three sides around the unit IJU, unnecessary portions such as dust and ink are provided so as not to reach the projections 2500 and 2600. The lid member 800 in which the parallel groove 3000 is formed forms an outer wall of the head cartridge and also forms a portion for accommodating the recording head unit IJU. The ink supply path member 600 in which the parallel groove 3001 is formed is connected to the above-described ink supply pipe 2200 to form an ink conduit 1600 that communicates with the ink supply pipe 2200. And a sealing pin 602 for securing capillary action with the ink supply pipe 2200 at the fixed portion of the ink conduit 1600. Note that reference numeral 601 denotes packing for sealing the ink tank and the supply pipe 2200, and 700 denotes a filter provided at the tank-side end of the supply pipe 2200. Since the ink supply path member 600 is molded, not only is it inexpensive and formed with high positional accuracy, but also the ink receiving port of the top plate 1300 of the conduit 1600 during mass production by the cantilevered conduit 1600. The pressure contact state with respect to 1500 can be stabilized. In this example, the sealing adhesive is poured from the ink supply path member side under this pressure contact state.
[0121]
The ink supply path member 600 is fixed to the support 300 by passing a pin (not shown) on the back side of the ink supply path member 600 to the holes 1901 and 1902 of the support 300 through the holes 1901 and 1902 of the support 300. This can be easily performed by projecting and heat-sealing a portion of the support body 300 projecting to the rear surface side. Note that the slightly protruding area of the heat-fused back surface is accommodated in a recess (not shown) in the side wall of the recording head unit IJU mounting surface of the ink tank, so that the positioning surface of the unit IJU can be obtained accurately.
[0122]
The ink tank includes a cartridge body 1000, an ink absorber 900, and a lid 1100 for sealing the ink absorber 900 after inserting the ink absorber 900 from the side of the cartridge body 1000 opposite to the unit IJU mounting surface. , Is composed. The absorber 900 is arranged in the cartridge main body 1000. The supply port 1200 is a supply port for supplying ink to the unit IJU including the above-described units 100 to 600, and the ink is injected from the supply port 1200 in a process before the unit is arranged in the portion 1010 of the cartridge body 1000. This is also an inlet for impregnating the absorber 900 with ink. In the head cartridge of the present example, the portions where the ink can be injected into the ink tank are the atmosphere communication port 1401 and the supply port 1200. However, the in-tank air presence regions formed by the ribs 2300 provided on the inner surface of the main body 1000 and the ribs 2500 and 2501 provided on the inner surface of the lid 1100 are provided in portions continuous from the atmosphere communication port 1401 side. In addition, by adopting a configuration provided over the corner portion farthest from the ink supply port 1200, good ink supply from the ink absorber is maintained. Therefore, it is important that relatively good and uniform ink injection into the absorber is performed through the supply port 1200. This method is extremely effective in practical use. The rib 2300 has four ribs (only two upper surfaces are shown in FIG. 18) parallel to the carriage moving direction at the rear of the cartridge main body 1000 to prevent the absorber from sticking to the main body 1000 surface. are doing. The partial ribs 2501 and 2500 are provided on the inner surface of the lid 1100 on the extension in the direction in which the rib 2300 extends, but are separated from the rib 2300. As a result, the space where air is present is increased compared to the former. Note that the ribs 2500 and 2501 are distributed over a surface that is less than half the total area of the lid 1100. With these ribs, the ink in the corner region farthest from the tank supply port 1200 of the ink absorber 900 can be more stably guided to the supply port 1200 side by capillary force. Reference numeral 1401 denotes an atmosphere communication port provided in the lid member for communicating the inside of the ink tank with the atmosphere. Reference numeral 1400 denotes a liquid repellent material disposed inside the air communication port 1401, which prevents ink from leaking from the air communication port 1400.
[0123]
The above-described arrangement of the ribs is particularly effective since the ink storage space of the ink tank has a rectangular shape and has long sides on the side surfaces, but the case where the ink storage space has a long side in the moving direction of the carriage or a cube is used. By providing a rib on the entire lid 1100, the ink supply from the ink absorber 900 can be stabilized.
[0124]
The unit IJU is surrounded except for the lower opening by the ink tank and the lid 800 that covers the unit IJU after the unit IJU is mounted thereon, but the head cartridge is mounted on the carriage on the apparatus main body side. At this time, since the lower opening is close to the carriage, a substantially four-sided surrounding space is formed. Therefore, heat generated from the recording head IJH in the surrounding space is effectively dispersed in the space and is effective in maintaining the space at a uniform temperature. However, when the head IJH is driven continuously for a long period of time, a slight temperature rise may occur. For this reason, in this example, a slit 1700 having a width smaller than this space is provided on the upper surface of the cartridge in order to assist natural heat radiation from the support member 300, and the temperature distribution of the entire unit IJU is prevented while preventing a temperature rise. Uniformity of the environment is not affected by the environment.
[0125]
As shown in FIG. 19, when assembled as a head cartridge IJC, ink is distributed from the supply port 1200 of the ink tank through the hole 320 provided in the support 300 and the introduction port provided on the inside and back side of the supply tank 600. The ink is guided to a conduit 1600 in the ink supply path member 600 through the supply pipe 2200 to be passed through the supply pipe 2200, and then flows into the common liquid chamber through the ink introduction port 1500 of the top plate 1300. A packing made of, for example, silicon rubber or burch rubber is provided at the connection portion between the supply pipe and the conduit, whereby sealing is performed and an ink supply path is secured.
[0126]
In this embodiment, the top plate 1300 is made of a resin such as polysulfone, polyethersulfone, polyphenylene oxide, or polypropylene having excellent ink resistance, and is integrally molded with the orifice plate 400 by a mold. .
[0127]
FIG. 20 is a schematic view of an ink jet recording apparatus IJRA using the ink jet recording head cartridge of the present invention. The ink jet cartridge IJC in which the recording head and the ink tank are integrated is mounted on the carriage HC. The carriage HC engages with a helical groove 5005 of a lead screw 5004 that rotates via driving force transmission gears 5011 and 50009 in conjunction with forward and reverse rotation of the drive motor 5013. The carriage HC has pins (not shown). Are reciprocated in the directions of arrows a and b. The recording head unit 5025 and the ink tank unit 5026 are mounted on the carriage HC. Reference numeral 5002 denotes a paper pressing plate, which presses the paper against the platen 5000 in the moving direction of the carriage. Photocouplers 5007 and 5008 are home position detecting means for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the motor 5013. Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the recording head, and reference numeral 5015 denotes suction means that suctions the inside of the cap, and performs suction recovery of the recording head through an opening 5023 in the cap. Reference numeral 5017 denotes a cleaning blade, and reference numeral 5019 denotes a member capable of moving the blade in the front-rear direction. These members are supported by a main body support plate 5018. It goes without saying that the blade is not limited to this form, and a well-known cleaning blade can be applied to this embodiment. Reference numeral 5012 denotes a lever for starting suction for suction recovery. The lever 5012 moves with the movement of the cam 5020 that engages with the carriage, and the driving force from the drive motor moves by a known transmission means such as clutch switching. Controlled.
[0128]
The capping, cleaning, and suction recovery are configured so that desired operations can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage HC is positioned in the home position side area. Any desired operation can be performed in this example.
[0129]
Although the ink jet recording apparatus using a cartridge type recording head and an ink tank integrated type has been described, an ink jet recording apparatus in which ink is supplied from an ink tank to a recording head by a very thin tube is also included in the present invention. Included.
[0130]
FIG. 21 is a block diagram of an entire apparatus for operating ink discharge recording to which the inkjet recording head of the present invention is applied.
[0131]
The recording device receives print information from the host computer 300 as a control signal. The print information is temporarily stored in the input interface 301 inside the printing apparatus, and at the same time, is converted into data that can be processed in the printing apparatus, and is input to the CPU 302 also serving as a head drive signal supply unit. The CPU 302 processes the data input to the CPU 302 using a peripheral unit such as the RAM 304 based on the control program stored in the ROM 303, and converts the data into print data (image data).
[0132]
Further, the CPU 302 generates drive data for driving a drive motor for moving the recording paper and the recording head in synchronization with the image data in order to record the image data at an appropriate position on the recording paper. The image data and the motor drive data are transmitted to the head 200 and the drive motor 306 via the head driver 307 and the motor driver 305, respectively, and driven at controlled timing to form an image.
[0133]
Examples of the recording medium which can be applied to the recording apparatus as described above and to which a liquid such as ink is applied include various papers, OHP sheets, plastic materials used for compact discs and decorative plates, cloth, aluminum, copper, etc. Metal materials, leather materials such as cowhide, pig skin and artificial leather, wood materials such as wood and plywood, ceramic materials such as bamboo materials and tiles, and three-dimensional structures such as sponges.
[0134]
As the above-mentioned recording device, a printer device for recording on various types of paper and OHP sheets, a recording device for plastics for recording on plastic materials such as compact discs, a recording device for metal for recording on metal plates, leather A recording device for leather that records on wood, a recording device for wood that records on wood, a recording device for ceramic that records on ceramic materials, a recording device that records on a three-dimensional network structure such as a sponge, or a fabric It also includes a textile printing device that performs recording.
[0135]
Further, as a discharge liquid used in these liquid discharge devices, a liquid suitable for each recording medium and recording conditions may be used.
[0136]
<Recording system>
Next, an example of an ink jet recording system that performs recording on a recording medium using the ink jet recording head of the present invention as a recording head will be described.
[0137]
FIG. 22 is a schematic diagram for explaining a configuration of an inkjet recording system using the above-described inkjet recording head 201 of the present invention. The ink jet recording head according to the present embodiment is a full line type head in which a plurality of ejection ports are arranged at intervals of 360 dpi in a length corresponding to the recordable width of the recording medium 150, and yellow (Y) and magenta (M). , Cyan (C), and black (Bk) are fixedly supported in parallel by a holder 202 at predetermined intervals in the X direction.
[0138]
A signal is supplied to each of these heads from a head driver 307 constituting a drive signal supply unit, and each head is driven based on this signal.
[0139]
To each head, four color inks of Y, M, C, and Bk are supplied as ejection liquids from ink containers 204a to 204d, respectively. Reference numeral 204e denotes a foaming liquid container in which a foaming liquid is stored. The foaming liquid is supplied from the container to each head.
[0140]
Below each head, head caps 203a to 203d in which an ink absorbing member such as a sponge is disposed are provided, and the head can be maintained by covering the ejection openings of each head during non-printing. Can be.
[0141]
Reference numeral 206 denotes a transport belt that constitutes a transport unit for transporting various types of non-recording media as described in each of the above embodiments. The transport belt 206 is drawn around a predetermined path by various rollers, and is driven by a driving roller connected to a motor driver 305.
[0142]
In the ink jet recording system of this embodiment, a pre-processing device 251 and a post-processing device 252 for performing various processes on a recording medium before and after recording are provided upstream and downstream of the recording medium transport path, respectively. .
[0143]
The pre-processing and post-processing differ depending on the type of recording medium on which recording is performed and the type of ink, but for example, for recording media such as metals, plastics, and ceramics, the pre-processing is performed as pre-processing. By irradiating ultraviolet rays and ozone to activate the surface, the adhesion of the ink can be improved. Further, in a recording medium such as plastic which easily generates static electricity, dust easily adheres to the surface due to the static electricity, and good recording may be hindered by the dust. For this reason, it is preferable to remove dust from the recording medium by removing static electricity from the recording medium by using an ionizer device as pretreatment. When a cloth is used as the recording medium, the cloth is selected from an alkaline substance, a water-soluble substance, a synthetic polymer, a water-soluble metal salt, urea, and thiourea from the viewpoint of preventing bleeding and improving the first-arrival rate. What is necessary is just to perform the process which gives a substance as preprocessing. The pre-processing is not limited to these, and may be a process of setting the temperature of the recording medium to a temperature suitable for recording.
[0144]
Post-processing, on the other hand, includes a fixing process for promoting the fixing of the ink to the recording medium to which the ink has been applied by heat treatment, ultraviolet irradiation, and the like, and a process for cleaning the processing agent applied in the pre-processing and remaining unreacted. Is what you do.
[0145]
In the present embodiment, a full-line head has been described as a head. However, the present invention is not limited to this, and the recording may be performed by transporting a small head as described above in the width direction of the recording medium. You may.
[Brief description of the drawings]
FIGS. 1A and 1B are plan views showing the configuration of a conventional nozzle portion as an embodiment and a comparative example of an ink jet recording head according to the present invention.
FIGS. 2A to 2C are diagrams illustrating a discharge amount Vd of a droplet, a discharge speed v, and a refill frequency fr when a distance OH from a discharge port to a heater tip is used as a variable.
FIG. 3 is a diagram showing a relationship between a distance OH and a product of a discharge amount Vd of a droplet and a discharge speed v, and a product of a discharge port area SO and a distance OH from a discharge port to a heater tip.
FIG. 4 is a diagram illustrating a relationship between a result obtained by dividing a discharge speed v by a discharge amount Vd and a distance OH.
FIG. 5 is a view mainly showing a longitudinal section of an ink path of a recording head according to an embodiment of the present invention.
FIG. 6 is a view similar to FIG. 1, illustrating an embodiment of the present invention.
FIG. 7 is a diagram illustrating a relationship between a discharge heater distance and a discharge ink droplet volume for explaining the above embodiment.
FIG. 8 is a diagram showing changes in curve curves a and b when the heater area SH is increased.
FIGS. 9A to 9D are cross-sectional views of an ink path for explaining the behavior of refilling at the time of ejection while comparing the embodiment with the conventional example.
FIG. 10 is a diagram showing a change in a proportional coefficient SO ′.
FIGS. 11A to 11C show discharge characteristics such as a discharge amount Vd, a discharge speed V, and a refill frequency fr, where a distance OP between the center of gravity of two heaters and a discharge port is a variable. FIG.
FIG. 12 is a diagram showing the shapes of nozzles and heaters used in measuring the characteristics of the inkjet recording head according to the present invention.
13A and 13B are diagrams showing ejection characteristics when the distance OH of the rear heater is fixed and the position of the front heater is changed, wherein FIG. 13A shows the ejection speed v, FIG. 13B shows the ejection amount Vd, and FIG. Are the values obtained by removing the discharge speed v by the discharge amount Vd. These values show the case where only the front heater is used and the case where the front heater and the rear heater are used simultaneously. (D) shows the amount of displacement in each case.
14A and 14B are diagrams showing ejection characteristics when the distance OH of the rear heater is fixed and the position of the front heater is changed, wherein FIG. 14A shows the ejection speed v, FIG. 14B shows the ejection amount Vd, and FIG. Are the values obtained by removing the discharge speed v by the discharge amount Vd. These values show the case where only the front heater is used and the case where the front heater and the rear heater are used simultaneously. (D) shows the amount of displacement in each case.
FIGS. 15A and 15B are diagrams for explaining a second embodiment of the present invention, and are plan views showing the configuration of nozzles 1001 and 1005 that discharge substantially the same ink droplets. .
FIG. 16 is a diagram illustrating an example of an ink jet recording cartridge according to the present invention.
FIG. 17 is a diagram illustrating an embodiment of the present invention.
FIG. 18 is an exploded perspective view illustrating an example of an inkjet head cartridge using an inkjet recording head.
FIG. 19 is a schematic perspective view of an ink jet head cartridge.
FIG. 20 is a schematic view of an ink jet recording apparatus IJRA.
FIG. 21 is a block diagram of the entire apparatus.
FIG. 22 is a schematic diagram illustrating a configuration of an inkjet recording system.
[Explanation of symbols]
101, 105 nozzle
102, 103, 106 heater
104, 107 outlet

Claims (2)

A first head including a plurality of liquid flow paths having a discharge port for discharging ink, and a plurality of electrothermal conversion elements disposed in each liquid flow path and generating thermal energy for discharging ink. When,
Including a plurality of liquid flow paths having discharge ports for discharging ink, and a plurality of electrothermal conversion elements provided in parallel with respect to each liquid flow path and having different shapes from the plurality of electrothermal conversion elements of the first head. An ink jet recording apparatus, which is used after being replaced with a second head and ejects ink,
The distance from the center of gravity of the plurality of electrothermal conversion elements to the discharge port in each liquid flow path of the first head, and the distance from the center of gravity of the plurality of electrothermal conversion elements to the discharge port in each liquid flow path of the second head. Are substantially the same. A first head including a plurality of liquid flow paths having discharge ports for discharging ink, and one electrothermal conversion element disposed in each liquid flow path and generating thermal energy for discharging ink. When,
  A second head including a plurality of liquid flow paths having discharge ports for discharging ink and a plurality of electrothermal transducers provided in parallel with respect to each liquid flow path is used by exchanging ink. An inkjet recording apparatus that performs
The distance from the center of gravity of the electrothermal conversion element in each liquid flow path of the first head to the discharge port and the distance from the center of gravity of both electrothermal conversion elements in each liquid flow path of the second head to the discharge port are: An ink jet recording apparatus, which is substantially the same.

Images