JP3799291B2 - Liquid composition, ink set, and method for forming colored portion on recording medium - Google Patents

Description

【０１４８】
更に、顔料を含む水溶液を分散処理する前にプレミキシングを３０分間以上行うと、顔料の分散効率がよくなる。このプレミキシング操作は、顔料表面の濡れ性を改善し、顔料表面への分散剤の吸着を促進するものである。
【０１４９】
アルカリ可溶型樹脂を使用した場合の分散液に添加される塩基類としては、例えば、モノエタノールアミン、ジエタノールアミン、トリエタノールアミン、アミンメチルプロパノール、アンモニア等の有機アミン或いは水酸化カリウム、水酸化ナトリウム等の無機塩基を用いることが好ましい。
【０１５０】
一方、顔料インクの調製に使用する分散機は、一般に使用される分散機ならいかなるものでもよいが、例えば、ボールミル、サンドミル等が挙げられる。その中でも、高速型のサンドミルが好ましく、例えば、スーパーミル、サンドグラインダー、ビーズミル、アジテータミル、グレンミル、ダイノールミル、パールミル、コボルミル（いずれも商品名）等が挙げられる。
【０１５１】
尚、本発明で使用するインクは、上記成分の他に必要に応じて、水溶性有機溶剤、界面活性剤、ｐＨ調製剤、防錆剤、防カビ剤、酸化防止剤、蒸発促進剤、キレート化剤及び水溶性ポリマー等の添加剤を添加してもよい。
【０１５２】
本発明で用いる、前記した色材を溶解又は分散する液媒体は、水と水溶性有機溶剤との混合物であることが好ましい。具体的な水溶性有機溶剤としては、例えば、メチルアルコール、エチルアルコール、ｎ−プロピルアルコール、イソプロピルアルコール、ｎ−ブチルアルコール、ｓｅｃ−ブチルアルコール、ｔｅｒｔ−ブチルアルコール等の炭素数１〜４のアルキルアルコール類、ジメチルホルムアミド、ジメチルアセトアミド等のアミド類、アセトン等のケトン類、テトラヒドロフラン、ジオキサン等のエーテル類、ポリエチレングリコール、ポリプロピレングリコール等のポリアルキレングリコール類、エチレングリコール、プロピレングリコール、ブチレングリコール、トリエチレングリコール、１，２，６−ヘキサントリオール、チオジグリコール、ヘキシレングリコール、ジエチレングリコール等のアルキレン基が２〜６個の炭素原子を含むアルキレングリコール類、グリセリン、エチレングリコールモノメチル（又はエチル）エーテル、ジエチレングリコールモノメチル（又はエチル）エーテル等の多価アルコールの低級アルキルエーテル類、Ｎ−メチル−２−ピロリドン、１，３−ジメチル−２−イミダゾリジノン、スルホラン、ジメチルサルフォオキサイド、２−ピロリドン、ε−カプロラクタム等の環状アミド化合物、及びスクシンイミド等のイミド化合物等が挙げられる。
【０１５３】
上記したような水溶性有機溶剤の含有量は、一般には、インクの全質量に対して質量％で１〜４０％が好ましく、より好ましくは３〜３０％の範囲である。また、インク中の水の含有量を３０〜９５質量％の範囲とした場合に、色材の溶解性等も良好であり、インクの粘度が高くなることを抑えることができ、且つインクの固着特性を十分に満足させたものとすることができる。
【０１５４】
本発明で使用するアニオン性インクは、一般の水性筆記用具としても使用できるが、熱エネルギーによるインクの発泡現象によりインクを吐出させるタイプのインクジェット記録方法に適用する場合に特に好適であり、吐出が極めて安定となり、サテライトドットの発生等が生じないという特徴がある。但し、この場合には、熱的な物性値（例えば、比熱、熱膨張係数、熱伝導率等）を調整する場合もある。
【０１７１】
＜水性インクの濃度＞
上記したアニオン性のインク中に含まれる色材成分の質量濃度は、水性染料、顔料や自己分散型顔料等の色材の種類に応じて適宜選択されるが、インクの質量に対し、０．１〜２０質量％、特には０．１〜１２質量％の範囲とすることが好ましい。また、色材成分の質量濃度が０．３〜７質量％の範囲では、液体組成物中の微粒子の濃度とインク中の色材の濃度との関係に関して、質量基準で、該微粒子１に対して色材が１．２以下、特には１．０以下とした場合に、通常の２液系の記録条件の下で形成される画像の発色性は特に優れたものとなる。
【０１７２】
＜被記録媒体に着色部を形成する方法＞
次に、先に説明した本発明にかかる液体組成物を使用する、本発明の被記録媒体に着色部を形成する方法について説明する。本発明の被記録媒体に着色部を形成する方法は、上記で説明したような色材を含むインクを被記録媒体に付与する工程（ｉ）、及び本発明にかかる液体組成物を被記録媒体に付与する工程（ii）とを有することを特徴とする。本発明においては、工程（ｉ）で、上記で説明したようなアニオン性の水性インクを用い、工程（ii）で、該インクとは逆の極性に表面が帯電している微粒子が分散状態で含まれている、先述した液体組成物を用いることが好ましい。そして、被記録媒体の表面において、これらの水性インクと液体組成物とが互いに液体状態で接するように付与するように構成することが好ましい。
以下、上述したような構成の液体組成物及び水性インクを被記録媒体上に付与する方法について説明する。
【０１７３】
本発明にかかる被記録媒体に着色部を形成する方法では、液体組成物を被記録媒体上に付与する工程（ii）と、インクを被記録媒体に付与する工程（ｉ）を有するが、その際に、被記録媒体における着色部形成領域、又は着色部形成領域とその近傍に液体組成物を付与して、水性インクと液体組成物とが互いに液体状態で接するように付与することが好ましい。ここでいう着色部形成領域とは、インクのドットが付着する領域のことであり、着色部形成領域の近傍とは、インクのドットが付着する領域の外側の１〜５ドット程度離れた領域のことを指す。
【０１７４】
本発明の被記録媒体に着色部を形成する方法では、前記した本発明の液体組成物と水性インクとが被記録媒体上で互いに液体状態で接するようになれば、これらをいずれの方法で付与させてもよい。従って、液体組成物とインクのいずれを先に被記録媒体上に付与するかは問題ではない。例えば、工程（ii）を行なった後に工程（ｉ）を行なってもよいし、工程（ｉ）を行なった後に工程（ii）を行なってもよい。また、工程（ｉ）を行なった後に、工程（ii）を行ない、その後に再び工程（ｉ）を行なうことも好ましい形態である。また、液体組成物を被記録媒体に先に付与させた場合に、液体組成物を被記録媒体に付与してから、インクを被記録媒体上に付与させるまでの時間については特に制限されるものではないが、互いに液体状態で接するようにするためには、ほぼ同時或いは数秒以内にインクを被記録媒体上に付与させることが好ましい。
【０１７５】
（被記録媒体）
上記した本発明の被記録媒体に着色部を形成する方法に使用される被記録媒体としては、特に限定されるものではなく、従来から使用されている、コピー用紙やボンド紙等の、いわゆる普通紙を好適に使用できる。勿論、インクジェット記録用に特別に作製されたコート紙や、ＯＨＰ用透明フィルムも好適に使用できる。更に、一般の上質紙や光沢紙にも好適に使用することができる。
【０１７６】
（液体組成物の付与方法）
本発明にかかる液体組成物を被記録媒体上に付与せしめる方法としては、例えば、スプレーやローラー等によって被記録媒体の全面に付与せしめる方法も考えられる。しかし、より好ましくは、インクを付与する着色部形成領域、或いは着色部形成領域とその着色部形成領域の近傍にのみに、選択的に且つ均一に液体組成物を付与せしめることのできるインクジェット方式によって行うのがよい。また、この際には、種々のインクジェット記録方式を用いることができるが、特に好ましいのは、熱エネルギーによって発生した気泡を用いて液滴を吐出する方式である。
【０１７７】
＜インクジェット記録装置＞
以下、本発明のインクジェット記録装置の具体例について説明する。
本発明のインクジェット記録装置の一形態は、色材を含むインクを収容したインク収容部と、該インクを吐出させるインクジェットヘッドを備えた第１の記録ユニットと、例えば、水性インクとは逆の極性に表面が帯電している微粒子が分散状態で含まれている本発明にかかる液体組成物を収容した液体組成物収容部と、該液体組成物を吐出させるインクジェットヘッドを備えた第２の記録ユニットとを備えていることを特徴とする。
【０１７８】
図１は、上記形態を有する本発明にかかるインクジェット記録装置である出力情報を記録するインクジェット方式のプリンタの概略構成の一例を示す、模式的斜視図である。図１において、１は、インクを吐出してプリントを行って着色部を形成するためのインクジェットヘッドを構成するカートリッジ（以下、プリント用ヘッドカートリッジ）であり、２は、液体組成物を吐出するための液体組成物吐出ヘッドを構成するカートリッジ（以下、液体組成物用ヘッドカートリッジ）である。図示した例では、異なる色のインクを用いる４個のプリント用ヘッドカートリッジ１と、１個の液体組成物用ヘッドカートリッジ２が使用されている。プリント用の各ヘッドカートリッジ１は、その上部にインクタンク部、下部にインク吐出部（プリント部）を設けた構造をしている。液体組成物用のヘッドカートリッジ２は、その上部に液体組成物タンク部、下部に液体組成物吐出部を設けた構造をしている。更に、これらのヘッドカートリッジ１及び２には、駆動信号等を受信するためのコネクタが設けられている。３はキャリッジである。
【０１７９】
キャリッジ３上には、それぞれ異なる色のインクでプリントするための４個のプリント用ヘッドカートリッジ１と、１個の液体組成物用ヘッドカートリッジ２が位置決め搭載されている。また、該キャリッジ３には、各プリント用ヘッドカートリッジ１及び液体組成物用ヘッドカートリッジ２を駆動するための信号等を伝達するためのコネクタホルダーが設けられており、該コネクタホルダーを介して各ヘッドカートリッジ１及び２に電気的に接続されている。
【０１８０】
各プリント用ヘッドカートリッジ１は、それぞれ異なった色のインク、例えば、イエロー（Ｙ）、マゼンタ（Ｍ）、シアン（Ｃ）、及びブラック（Ｂ）のインクが収納されている。本図では、図示左から、イエロー、マゼンタ、シアン、及びブラックの各インクのプリント用ヘッドカートリッジ１Ｙ、１Ｍ、１Ｃ、及び１Ｂが搭載され、そして右端には、前記液体組成物を収納した液体組成物用ヘッドカートリッジ２が搭載されている。
【０１８１】
図１において、４は、キャリッジ３の主走査方向に延在し該キャリッジを摺動自在に支持する走査レール、５は、キャリッジ３を往復動させるための駆動力を伝達する駆動ベルトである。また、６、７及び８、９は、それぞれ、各ヘッドカートリッジのプリントヘッドによるプリント位置の前後に配置されて被記録媒体１０の挟持搬送を行うための搬送ローラ対である。紙等の被記録媒体１０は、プリント位置の部分で、プリント面を平坦に規制するためのプラテン（不図示）に圧接状態で案内支持されている。この時、キャリッジ３に搭載された各ヘッドカートリッジ１及び２の吐出口形成面は、該キャリッジ３から下方へ突出して被記録媒体搬送用ローラ７、９間に位置し、プラテン（不図示）の案内面に圧接された被記録媒体１０に平行に対向するようになっている。
【０１８２】
本図のインクジェットプリンタのプリント領域を外れた左側に設定されたホームポジションの近傍には、回復ユニット１１が配設されている。回復ユニット１１には、４個のプリント用ヘッドカートリッジ１Ｙ、１Ｍ、１Ｃ、及び１Ｂのインク吐出部に対応する４個のキャップ１２と、１個の液体組成物用ヘッドカートリッジ２の液体組成物吐出部に対応する１個のキャップ１３が上下方向に昇降可能に設けられている。そして、キャリッジ３がホームポジションにあるときには、各ヘッドカートリッジ１及び２の吐出部の吐出口形成面に対して、対応するキャップ１２及び１３とが圧接接合されることにより、各ヘッドカートリッジ１及び２の吐出口が密封（キャッピング）される。キャッピングすることにより、吐出口内のインク溶剤の蒸発によるインクの増粘・固着が防止され、吐出不良の発生が防止されている。
【０１８３】
また、回復ユニット１１は、各キャップ１２に連通した吸引ポンプ１４とキャップ１３に連通した吸引ポンプ１５を備えている。これらのポンプ１４及び１５は、プリント用ヘッドカートリッジ１や液体組成物用ヘッドカートリッジ２に吐出不良が生じた場合に、それらの吐出口形成面をキャップ１２及び１３でキャッピングして、吸引回復処理を実行するのに使用される。更に、回復ユニット１１には、ゴム等の弾性部材からなる２個のワイピング部材（ブレード）１６及び１７が設けられている。ブレード１６はブレードホルダー１８によって保持され、ブレード１７はブレードホルダー１９によって保持されている。
【０１８４】
図に示した装置においては、前記ブレードホルダー１８、１９は、それぞれ、キャリッジ３の移動を利用して駆動されるブレード昇降機構（不図示）により昇降され、それによって、前記ブレード１６及び１７は、各ヘッドカートリッジ１及び２の吐出口形成面に付着したインクや異物をワイピングすべく突出（上昇）した位置（ワイピング位置）と吐出口形成面に接触しない後退（下降）した位置（待機位置）との間で昇降する。この場合、プリント用ヘッドカートリッジ１の吐出口形成面をワイピングするブレード１６（以下、インク用ブレード）と液体組成物用ヘッドカートリッジ２の吐出口形成面をワイピングするブレード１７（以下、液体組成物用ブレード）は、互いに独立して、個別に昇降できるように構成されている。
【０１８５】
そして、キャリッジ３が図１中右側（プリント領域側）からホームポジション側へ移動するとき、或いはホームポジション側からプリント領域側へ移動するときに、ブレード１６が各プリント用ヘッドカートリッジ１の吐出口形成面と当接し、ブレード１７が液体組成物吐出ヘッド２の吐出口形成面と当接し、相対移動によってそれらの吐出口形成面の拭き取り（ワイピング）動作が行われる。
【０１８６】
図２は、インク吐出部とインクタンクを一体化した構造のプリント用ヘッドカートリッジ１を示す模式的斜視図である。尚、液体組成物用ヘッドカートリッジ２は、貯蔵及び使用する液体が液体組成物である点を除き、プリント用ヘッドカートリッジ１と実質上同じ構成をしている。図２において、プリント用ヘッドカートリッジ１は、上部にインクタンク部２１を、下部にインク吐出部（プリントヘッド部）２２を有しており、更に、インク吐出部２２を駆動するための信号等を受信すると共に、インク残量検知信号を出力するためのヘッド側コネクタ２３を有している。このコネクタ２３はインクタンク部２１に並ぶ位置に設けられている。
プリント用ヘッドカートリッジ１は、図２中、底面側（被記録媒体１０側）に吐出口形成面８１を有し、該吐出口形成面８１には複数の吐出口が形成されている。各吐出口に通じる液路部分に、インクを吐出するのに必要なエネルギーを発生する吐出エネルギー発生素子が配置されている。
【０１８７】
前記プリント用ヘッドカートリッジ１は、そのインク吐出部からインクを吐出してプリントを行うインクジェットプリント手段であり、インク吐出部２２とインクタンク２１とを一体化した交換可能なインクジェットカートリッジで構成されている。このプリント用ヘッドカートリッジ１は、熱エネルギーを利用してインクを吐出するインクジェットプリント手段であって、熱エネルギーを発生するための電気熱変換体を備えたものである。また、前記プリント用ヘッドカートリッジ１は、前記電気熱変換体によって印加される熱エネルギーにより生じる膜沸騰による気泡の成長、収縮によって生じる圧力変化を利用して、吐出口よりインクを吐出させ、プリントを行なうものである。
【０１８８】
図３は、プリント用ヘッドカートリッジ１（液体組成物用ヘッドカートリッジ２）のインク吐出部２２（液体組成物吐出部２２Ａ）の構造を模式的に示す部分斜視図である。図３において、被記録媒体（プリント用紙等）１０と所定の隙間（例えば、約０．５〜２．０ｍｍ程度）をおいて対面する吐出口形成面８１には、所定のピッチで複数の吐出口８２が形成され、共通液室８３と各吐出口８２とを連通する各液路８４の壁面に沿ってインク吐出用のエネルギーを発生するための電気熱変換体（発熱抵抗体等）８５が配設されている。前記複数の吐出口８２はプリント用ヘッドカートリッジ１の移動方向（主走査方向）と交叉する方向に並ぶような位置関係で配列されている。こうして、画像信号または吐出信号に基づいて対応する電気熱変換体８５を駆動（通電）して、液路８４内のインクを膜沸騰させ、その時に発生する圧力によって吐出口８２からインクを吐出させるプリント用ヘッドカートリッジ１が構成されている。
【０１８９】
ここで、プリント用ヘッドカートリッジ１及び２が備えている、インクを保持しているインクタンク、並びに液体組成物を保持しているタンク（説明の簡略化のため、このタンクもインクタンクと称する）を構成する部材は、インクや液体組成物と接触するため耐薬品性に優れるものが好ましく用いられる。その要件を満たし、且つ一般に入手し易い材料としては、例えば、ポリオレフィン系樹脂やポリ塩化ビニル、ポリ塩化ビニリデン、シリコーン樹脂、エチレン−酢酸ビニル共重合体、ＡＢＳ樹脂、ポリアセタール、ナイロン、不飽和ポリエステル樹脂、ＰＥＴ、アラミド樹脂等の樹脂材料や、スチレンブタジエンゴム（ＳＢＲ）、ブタジエンゴム、クロロプレン、ニトリルゴム、ブチルゴム、ＥＰＤＭ、ウレタンゴム、シリコーンゴム、アクリルゴム、エピクロルヒドリンゴム、フッ素ゴム等の合成ゴムが挙げられる。これらの樹脂や合成ゴムは、それ自身を構成する化学物質以外に、安定剤やＵＶ吸収剤、酸化防止剤等多くの添加助剤が、目的に応じて適当量添加されている。
【０１９０】
本発明者らの検討によれば、この場合に、これらの添加剤成分がインクや液体組成物中へ溶出し、該溶出成分がインクや液体組成物の組成分と反応して、不溶物を生成する場合がある。上記した成分の中でも特に、脂肪酸や脂肪酸誘導体類は、インクや液体組成物中へ溶出し、温度等の環境変化によって再び析出して不溶物を作ったり、また、インクや液体組成物中に含まれている溶存イオンと溶出物が反応し、脂肪酸塩の不溶物を生成したりして、フィルターや吐出口をつまらせ、インクの流れを妨げる場合があった。このような部材からの溶出物自体の析出や、該溶出物とインクや液体組成物中の成分との反応による不溶物の析出を防ぐためには、例えば、インクタンクを形成する樹脂成分中の添加剤含有量を少なくしたり、溶出し難い材料の選択や、インクや液体組成物の溶剤組成の変更、インクや液体組成物中の反応成分の含有量を少なくする等の対策を講じることが有効である。このような手段によって、上記した析出を抑制することができる。
【０１９１】
図４〜図６は、以上のインクジェットプリンタのワイピング動作を示す模式図である。図４は、キャリッジ３がプリント領域側からホームポジション側へ移動する場合を示す。図４において、（Ａ）のようにキャリッジ４上のプリント用ヘッドカートリッジ１及び液体組成物用ヘッドカートリッジ２が右側（プリント領域側）よりホームポジションに向かって移動してくる。そうすると、（Ｂ）のように、先ず、インク用のキャップ１２と液体組成物用のキャップ１３との間にあるインク用ブレード１６が上昇し、キャリッジ３の移動に伴って各プリントヘッド１Ｙ、１Ｍ、１Ｃ、１Ｂを順次ワイピングしていく。
【０１９２】
更に、図４の（Ｃ）のように、各プリント用ヘッドカートリッジ１が、液体組成物用ブレード１７上を通過した後、この液体組成物用ブレード１７を上昇させて（Ｄ）のように液体組成物ヘッドカートリッジ２の吐出口形成面を同時にワイピングする。インク用ブレード１６が４個目のプリントヘッド１をワイピングし、更に液体組成物用ブレード１７が液体組成物用ヘッドカートリッジ２の吐出部をワイピングし終わった後、それぞれのブレード１６、１７は下降し、待機位置で待機する。図４では、キャリッジ３が図１中の右側（プリント領域）から回復ユニット１１の有るホームポジション側へ移動するときにブレード１６、１７によるワイピングが実行されるように構成したが、ワイピング方向はこれに限定されるものではなく、図５のようにキャリッジ３がホームポジション側から右側（プリント領域側）へ移動する際にワイピングを行うように構成してもよい。
【０１９３】
図５において、（Ａ）では、インク用ブレード１６と液体組成物用ブレード１７を同時に上昇させ、キャリッジ３を右方向へ（プリント領域側へ）移動させることにより、プリント用ヘッドカートリッジ１と液体組成物用ヘッドカートリッジ２を同時にワイピングし（Ｂ）、液体組成物用ヘッドカートリッジ２のワイピングが終了すると同時に液体組成物用のブレード１７のみを下降させて待機させ、インク用ブレード１６はそのまま残りのプリント用ヘッドカートリッジ１のワイピングを行う（Ｃ）。最後に、図５の（Ｄ）のように、全てのプリント用ヘッドカートリッジ１のワイピングが終了したところで、インク用ブレード１６を下降させて一連のワイピング動作を終了する。図５で説明したようなワイピング方向を採用することにより、ワイピングにより除去されてブレード１６及び１７に付着した液滴が該ブレードの弾性によって被記録媒体１０の搬送部へ飛散し、被記録媒体１０を不用意に汚す危険性を無くすことができる。
【０１９４】
更に、図６に示すように、プリント用ヘッドカートリッジ１のワイピング方向と液体組成物用ヘッドカートリッジ２のワイピング方向を異ならせてもよい。図６において、例えば（Ａ）及び（Ｂ）に示すように、キャリッジ３がホームポジション側から右側（プリント領域側）へ移動するときにインク用ブレード１６でプリント用ヘッドカートリッジ１をワイピングし、（Ｃ）及び（Ｄ）に示すように、キャリッジ３がプリント領域側からホームポジション側へ移動するときに液体組成物用ブレード１７で液体組成物用ヘッドカートリッジ２の吐出部のみをワイピングするようにしてもよい。このようなワイピング方向を採ることにより、ブレード１６の弾性力によって飛散するインクが液体組成物用ヘッドカートリッジ２の吐出部に付着したり、逆に、ブレード１７の弾性力によって飛散した液体組成物がプリント用ヘッドカートリッジ１の吐出部に付着するという不都合（危険性）をなくすか、大幅に減少させることができる。
【０１９５】
また、図１においては、プリント用ヘッドカートリッジ１用のキャップ１２と液体組成物用ヘッドカートリッジ２用のキャップ１３とを別々にして互いに独立させ（専用にし）、更に、これらのキャップ１２及び１３に接続される吸引ポンプ１４、１５も、プリント用ヘッドカートリッジ１用と、液体組成物用ヘッドカートリッジ２用とに独立させて別々（専用）にした。これにより、キャップ１２、１３、及びポンプ１４、１５内において、インクと該インクと反応性を有する液体組成物とを接触させることなく、これらの廃液を処理することができ、高い信頼性を維持することが可能になる。
【０１９６】
図７は、ポンプ１４、１５から排出されるインク及び液体組成物を廃インクタンク内へ回収するための回収系統を示す模式図である。図７において、キャップ１２に連通した吸引ポンプ１４によりプリント用ヘッドカートリッジ１から吸引された廃インク、並びにキャップ１３に連通した吸引ポンプ１５により液体組成物用ヘッドカートリッジ２から吸引された廃液は、プリンタ外へ漏れ出さないように、それぞれ独立した経路を通して廃液タンク２４内に回収され、収納される。
【０１９７】
前記廃液タンク２４は、その内部に多孔質の吸収体２５が充填され、該吸収体２５に廃液を吸収保持するように構成されている。この廃液タンク２４は、プリンタ本体内に設けられている。図７では、プリント用ヘッドカートリッジ１用の吸引ポンプ１４からの廃インク導管２６と液体組成物用ヘッドカートリッジ２用の吸引ポンプ１５からの廃液導管２７とは、図示のように、廃液タンク２４の両端の互いに離れた位置に接続されている。こうすることにより、廃液タンク２４内の液体組成物とインクは吸収体２５内に液が充分に吸収された状態ではじめて接触するようになるため、多孔質吸収体２５が吸収保持できる液の量を充分に確保することができる。
【０１９８】
図８は、図７の廃液回収系統において、廃液タンク２４内の吸収体２５を上下２段に配置し、下段の吸収体２５Ａにインクを吸収させ、上段の吸収体２５Ｂに液体組成物を吸収させるように構成した廃液回収系統を示す模式図である。図８の構成によれば、下段のインク吸収体２５Ａが溢れた場合でも、上段の吸収体２５Ｂとそこに吸収されている液体組成物により、インク中の染料は上段の吸収体２５Ｂで反応し固定化されるため、該インクが漏れ出してプリンタ内外を汚すことはない。
【０１９９】
また、本発明の別の形態のインクジェット記録装置は、好ましくは、色材を含む、アニオン性若しくはカチオン性の水性インクを収容したインク収容部と、上記水性インクとは逆の極性に表面が帯電している微粒子が分散状態で含まれている前記本発明にかかる液体組成物を収容した液体組成物収容部と、上記インク収容部に収容されている水性インクと上記液体組成物収容部に収容されている液体組成物とを各々独立に吐出させるためのインクジェットヘッドとを備えていることを特徴とする。以下、かかる形態のインクジェット記録装置について説明する。
【０２００】
図１０は、そのような形態のインクジェット記録装置の一例であるカートリッジ１００１を示すものであるが、図中の１００３は、インクが収容されているインク収容部、１００５は、液体組成物が収容されている液体組成物収容部である。該カートリッジは、図１１に示すように、インク及び液体組成物の各々を吐出せしめる記録ヘッド１１０１に着脱可能に構成されてなると共に、カートリッジ１００１を記録ヘッド１１０１に装着した状態では、液体組成物及びインクが、記録ヘッド１１０１に供給されるように構成されているものである。
【０２０１】
本発明のインクジェット記録装置は、上記の如きヘッドとインクカートリッジとが別体となったものに限らず、図１５に示す如きそれらが一体となったものでもよい。図１５において、１５００は、記録ユニットであって、この中にインクを収容したインク収容部、例えば、インク吸収体が収納されており、かかるインク吸収体中のインクが、複数のオリフィスを有するヘッド部１５０１からインク滴として吐出される構成になっている。インク吸収体の材料としては、例えば、ポリプロピレンやポリウレタンを用いることができる。１５０２は、記録ユニット内部を大気に連通させるための大気連通口である。
【０２０２】
更に、本発明で使用する記録ユニットの他の実施態様として、インクと液体組成物とを、１個のインクタンク内の各々の収納部に収納し、且つインク及び液体組成物の各々を吐出させるための記録ヘッドを一体的に備えた記録ユニット、具体的には、例えば、図１２に示すように、液体組成物を収容部１２０１Ｌに、ブラックインクを収容部１２０１Ｂｋに、また、イエロー、シアン及びマゼンタのカラーインクを各々カラーインク収納部１２０１Ｙ、１２０１Ｍ及び１２０１Ｃに収納し、更に、これらを各々個別に吐出させることができるように、インク流路を分けて構成した記録ヘッド１２０３を備えているような記録ユニット１２０１が挙げられる。
【０２０３】
図１６は、本発明のインクジェット記録装置であるインクジェットプリンタの他の実施態様の概略構成を示す、模式的斜視図である。
図１６において、４は、キャリッジ３の主走査方向に延在し、該キャリッジを摺動自在に支持する走査レール、５は、キャリッジ３を往復動させるための駆動力を伝達する駆動ベルトである。また、６、７及び８、９は、それぞれ、プリントヘッドによるプリント位置の前後に配置されて被プリント材１０の挟持搬送を行うための搬送ローラ対である。紙等の被プリント材１０は、プリント位置の部分で、プリント面を平坦に規制するためのプラテン（不図示）に圧接状態で案内支持されている。この時、キャリッジ３に搭載された各ヘッドカートリッジ１及び２の吐出口形成面は、該キャリッジ３から下方へ突出して被記録媒体搬送用ローラ７、９間に位置し、プラテン（不図示）の案内面に圧接された被記録媒体１０に平行に対向するようになっている。
【０２０４】
図１６において、キャリッジ３上には合計６個のヘッドカートリッジが位置決め搭載されており、本実施例では、キャリッジ３上の図示左端から右側へ向けて、イエローのプリン用ヘッドカートリッジ１Ｙ、マゼンタのプリント用ヘッドカートリッジ１Ｍ、シアンのプリント用ヘッドカートリッジ１Ｃ、ブラックのプリント用ヘッドカートリッジ１Ｂ、液体組成物用ヘッドカートリッジ２、第２のブラックのプリント用ヘッドカートリッジ１ＢＢの順に配置されている。液体組成物用ヘッドカートリッジ２は、インク中の色材と反応性を有する本発明の液体組成物を被記録媒体１０へ吐出するものである。また、右端の第２のブラックのプリント用ヘッドカートリッジ１ＢＢは、往復プリントでの副走査プリント時等に使用されるブラックインクを用いるプリント用ヘッドカートリッジである。つまり、前述の各実施例におけるブラックプリント用ヘッドカートリッジ１Ｂの次に（右隣に）液体組成物用ヘッドカートリッジ２を配置し、更にその次に（右端）に前記ブラックのプリント用ヘッドカートリッジ１ＢＢを配置する構成が採られている。
【０２０５】
図１６において、プリント領域の左側には回復ユニット１１が配設され、該回復ユニット１１においては、前記ヘッドカートリッジ１及び２の配置に対応して、左から右へ、プリント用ヘッドカートリッジ１Ｙ、１Ｍ、１Ｃ、１Ｂの吐出部をキャッピングするキャップ１２が順次配置され、その次に（右隣に）液体組成物用ヘッドカートリッジ２の吐出部をキャッピングするキャップ１３が配置され、更に、その右隣（右端）には第２のブラックプリント用ヘッドカートリッジ１ＢＢの吐出部をキャッピングするキャップ１２が配置されている。そして各々のキャップは、上下方向に昇降可能に設けられており、キャリッジ３がホームポジションにあるときには、各ヘッド１、２の吐出口形成面に対して対応するキャップ１２、１３が各々圧接されることにより、各ヘッドカートリッジ１及び２の吐出口が密封（キャッピング）され、これにより吐出口内のインク溶剤の蒸発によるインクの増粘や、固着が防止され、吐出不良の発生が防止されている。
【０２０６】
また、回復ユニット１１は、各キャップ１、２に連通した吸引ポンプ１４とキャップ１３に連通した吸引ポンプ１５を備えている。これらのポンプ１４、１５はプリント用ヘッドカートリッジ１や液体組成物用ヘッドカートリッジ２の吐出部に吐出不良が生じた場合に、それらの吐出口形成面をキャップ１２、１３でキャッピングして吸引回復処理を実行するのに使用される。更に、左端から５番目の液体組成物用のキャップ１３と６番目（右端）のブラックインク用のキャップ１２との間に、液体組成物用のブレード１７が配置され、右端のキャップ１２の右側（プリント領域側）に各プリント用ヘッドカートリッジ１の吐出部用のブレード１６が配置されている。そしてブレード１７はブレードホルダー１９によって保持され、ブレード１６はブレードホルダー１８によって保持されている。
【０２０７】
この態様においては、ブレードホルダー１９は、各々キャリッジ３の移動を利用して駆動されるブレード昇降機構（不図示）による昇降され、それによってブレード１６及び１７は、ヘッドカートリッジ１及び２の吐出口形成面に付着したインクや異物をワイピングすべく突出した位置（ワイピング位置）と吐出口形成面に接触しない後退した位置（待機位置）との間で昇降する。この場合、プリント用ヘッドカートリッジ１の吐出部をワイピングするブレード１６と液体組成物用ヘッドカートリッジ２の吐出部をワイピングするブレード１７は、互いに独立して個別に昇降できるように構成されている。
【０２０８】
図１７は、図１６のインクジェットプリントターのワイピング動作を示す模式図である。図１６において、（Ａ）に示すように、プリン用のブレード１６が突出（上昇）した後、キャリッジ３に搭載された各ヘッドが右側（プリント領域側）からホームポジションに向かって移動してくる。上昇したインク用ブレード１６は、（Ｂ）に示すように、キャリッジ３の左向き移動に伴いプリントヘッド１を順次ワイピングしていく。そして、（Ｃ）に示すように、液体組成物用ヘッドカートリッジ２が、インク用ブレード１６の手前（右隣）にきた時点で、該ブレード１６が待機位置まで後退（下降）し、該ブレード１６と液体組成物ヘッドカートリッジ２の吐出ヘッドとの接触が防止される。
【０２０９】
更に、キャリッジ３が左向きに移動して、液体組成物用ヘッドカートリッジ２がプリントヘッド用ブレード１６を通過した時点で、（Ｄ）に示すように、インク用ブレード１６、及び液体組成物用ブレード１７の両方を突出（上昇）させる。そして、キャリッジ３の左向き移動に伴って、（Ｅ）に示すように、ブレード１７による液体組成物用ヘッドカートリッジ２のワイピングとブレード１６による右端のプリントヘッド１ＢＢのワイピングを同時に行う。全てのヘッド１、２のワイピングが終了した後、（Ｆ）に示すように、両方のブレード１６、１７を後退（下降）させ、待機位置で待機させる。
【０２１０】
図１６及び図１７の実施例では、キャリッジ３がプリント領域側（右側）から回復ユニット１１のあるホームポジション側へ移動するときにブレード１６及び１７によるワイピングを行うようにしたが、ワイピング方向はこれに限定されるものではなく、ホームポジション側から右側（プリント領域側）へ移動する際にワイピングするようにしてもよい。
【０２１１】
図１６のインクジェットプリンタは、液体組成物吐出ヘッド２からインク中の色材と反応性を有するような、本発明にかかる液体組成物を被記録媒体１０に吐出し、各プリントヘッド０１から吐出されたインクと被記録媒体１０上で接触させて記録物を形成可能なように構成されている。被記録媒体１０上ではインク中の色材が液体組成物と反応することによって、インク中の色材が単分子状態で微粒子表面に吸着し、その微粒子によって画像の形成がなされるため、発色性や色の均一性に優れた画像が得られる。
【０２１２】
尚、本発明に使用する記録装置において、上記ではインク及び液体組成物に熱エネルギーを作用させてインク液滴を吐出するインクジェット記録装置を例に挙げたが、その他、圧電素子を使用するピエゾ方式のインクジェット記録装置でも同様に利用できる。
ところで、本発明にかかるインクジェット記録装置は、上記した構成を有するインクジェット記録装置に限定されず、例えば特開平１０−１４６９９１号公報に開示されているような構成を有し、ヘッドのワイピングブレードの動作方向が上記したインクジェット記録装置と異なっているインクジェット記録装置であってもよい。
【０２１３】
【実施例】
次に、実施例及び比較例を挙げて本発明を更に具体的に説明する。尚、文中、部及び％とあるのは、特に断りのない限り質量基準である。また、文中のゼータ電位は、微粒子の固形分濃度が０．１％になるよう液体組成物をイオン交換水で分散させた後に、ゼータ電位測定機（ブルックヘブン社製、ＢＩ−ＺＥＴＡｐｌｕｓ、液温２０℃、アクリルセル使用）で測定した値である。また、ｐＨは、作成した液体組成物に対し、液温２５℃でｐＨメーター計（堀場製作所（株）製、カスタニーｐＨメーターＤ−１４）を用いて測定した。微粒子の平均粒子直径は、微粒子の固形分濃度が０．１％になるように、液体組成物をイオン交換水で分散させた後に、動的光散乱法粒度分布計（ブルックヘブン社製、ＢＩ−９０、液温２０℃、アクリルセル使用）を用いて測定した。
【０２１４】
先ず、液体組成物の作製について説明する。実施例で使用した液体組成物Ａ〜Ｄは、後述する各成分を混合溶解した後、ポアサイズが１μｍのメンブレンフィルター（商品名、フロロポアフィルター、住友電工（株）製）にて加圧濾過することで作製した。また、液体組成物の細孔半径分布及び細孔容積は、下記の（１）〜（３）の手順に従って前処理した後、試料をセルに入れ、１２０℃で８時間真空脱気して、カンタクローム社製のオムニソーブ１を用いて窒素吸着脱離法により測定した。細孔半径及び細孔容積は、Barrettらの方法（J．Am．Chem．Soc.，Vol．７３、３７３、１９５１）により計算から求めた。また、ＢＥＴ比表面積は、Brunauerらの方法（J．Am．Chem．Soc.，Vol．６０、３０９、１９３８）により計算から求めた。
（１）測定対象の液体組成物を大気雰囲気下１２０℃で１０時間乾燥して、ほぼ溶媒分を蒸発させて乾燥する。
（２）上記乾燥物を１２０〜７００℃まで１時間で昇温させた後、７００℃で３時間焼成する。
（３）焼成後、得られた焼成物を徐々に常温に戻し、焼成物をメノウ乳鉢で摺り潰して粉体化する。
【０２１５】
（アルミナ水和物の合成例）
先ず、米国特許明細書第４，２４２，２７１号に記載の方法でアルミニウムドデキシドを製造した。次に、米国特許明細書第４，２０２，８７０号に記載された方法で、上記で得られたアルミニウムドデキシドを加水分解してアルミナスラリーを製造した。このアルミナスラリーをアルミナ水和物の固形分が８．２％になるまで水を加えた。アルミナスラリーのｐＨは９．７であった。３．９％の硝酸溶液を加えてｐＨを調整し、表１に示した各熟成条件でコロイダルゾルを得た。更に、このコロイダルゾルを８３℃でスプレードライすることによって、Ａ〜Ｄのアルミナ水和物を作製した。このアルミナ水和物は、いずれも水中で表面がプラスに帯電し、カチオン性を示した。これらのアルミナ水和物をイオン交換水に分散させてコロジオン膜上に滴下して測定用試料を作製し、透過型電子顕微鏡で観察したところ、すべて平板形状の微粒子であった。
【０２１６】
また、これらのアルミナ水和物粉体を試料をセルに入れ、１２０℃で８時間真空脱気して、カンタクローム社製のオムニソーブ１を用いて窒素吸着脱離法により測定し、Brunauerらの方法（J．Am．Chem．Soc.，Vol．６０、３０９、１９３８）によりＢＥＴ比表面積を計算から求めた。得られた各アルミナ水和物Ａ〜ＤのＢＥＴ比表面積を表１に示した。
【０２１７】

【０２１８】

【０２１９】
上記で得られた液体組成物ＡのｐＨは３．８であり、ゼータ電位は＋３５ｍＶであった。また、キヤノン製ＢＪＦ８５００用インクタンク（ＢＣＩ−８ＷＦ）と同型のインクタンクに液体組成物Ａを充填し、６０℃／Ｄｒｙ・１ヶ月の保存試験を行ったところ、保存後もインクタンク内に沈降物は見られず、このインクタンクをキヤノン製プリンターＢＪＦ８５００に装着した際の記録ヘッドからの吐出安定性も良好であった。また、液体組成物Ａから、先に説明した（１）〜（３）の手順に従った前処理後に得られた微粒子凝集物は、細孔半径が３ｎｍ〜３０ｎｍの範囲における細孔容積が０．９５ｍｌ／ｇであり、３０ｎｍを越える範囲での細孔容積は０．０１５ｍｌ／ｇであった。また、３ｎｍ〜２０ｎｍの範囲での細孔容積は０．８８ｍｌ／ｇであり、２０ｎｍを越える範囲での細孔容積は０．０９ｍｌ／ｇであった。また、微粒子凝集物のＢＥＴ比表面積は７４ｍ²／ｇであった。
【０２２０】

【０２２１】
上記で得られた液体組成物ＢのｐＨは３．７であり、ゼータ電位は＋３７ｍＶであった。また、キヤノン製ＢＪＦ８５００用インクタンク（ＢＣＩ−８ＷＦ）と同型のインクタンクに液体組成物Ｂを充填し、６０℃／Ｄｒｙ・１ヶ月の保存試験を行ったところ、インクタンク内に沈降物は見られず、このインクタンクをキヤノン製プリンターＢＪＦ８５００に装着した際の記録ヘッドからの吐出安定性も良好であった。また、液体組成物Ｂから、先に説明した（１）〜（３）の手順に従った前処理後に得られた微粒子凝集物は、細孔半径が３ｎｍ〜３０ｎｍの範囲における細孔容積は０．９２ｍｌ／ｇであり、３０ｎｍを越える範囲での細孔容積は０．００９ｍｌ／ｇであった。また、３ｎｍ〜２０ｎｍの範囲での細孔容積は０．９１ｍｌ／ｇであり、２０ｎｍを越える範囲での細孔容積は０．０１５ｍｌ／ｇであった。また、微粒子凝集物のＢＥＴ比表面積は１０３ｍ²／ｇであった。
【０２２２】

【０２２３】
上記で得られた液体組成物ＣのｐＨは３．７であり、ゼータ電位は＋４０ｍＶであった。また、キヤノン製ＢＪＦ８５００用インクタンク（ＢＣＩ−８ＷＦ）と同型のインクタンクに液体組成物Ｃを充填し、６０℃／Ｄｒｙ・１ヶ月の保存試験を行ったところ、インクタンク内に沈降物は見られず、このインクタンクをキヤノン製プリンターＢＪＦ８５００に装着した際の記録ヘッドからの吐出安定性も良好であった。また、液体組成物Ｃから、先に説明した（１）〜（３）の手順に従った前処理後に得られた微粒子凝集物は、細孔半径が３ｎｍ〜３０ｎｍの範囲における細孔容積は０．５１ｍｌ／ｇであり、３０ｎｍを越える範囲での細孔容積は０．００１ｍｌ／ｇであった。また、３ｎｍ〜２０ｎｍの範囲での細孔容積は０．５０ｍｌ／ｇであり、２０ｎｍを越える範囲での細孔容積は０．００７ｍｌ／ｇであった。また、微粒子凝集物のＢＥＴ比表面積は１９２ｍ²／ｇであった。
【０２２４】

【０２２５】
上記で得られた液体組成物ＤのｐＨは３．７であり、ゼータ電位は＋４０ｍＶであった。また、キヤノン製ＢＪＦ８５００用インクタンク（ＢＣＩ−８ＷＦ）と同型のインクタンクに液体組成物Ｄを充填し、６０℃／Ｄｒｙ・１ヶ月の保存試験を行ったところ、インクタンク内に沈降物は見られず、このインクタンクをキヤノン製プリンターＢＪＦ８５００に装着した際の記録ヘッドからの吐出安定性も良好であった。また、液体組成物Ｃから、先に説明した（１）〜（３）の手順に従った前処理後に得られた微粒子凝集物は、細孔半径が３ｎｍ〜３０ｎｍの範囲における細孔容積は０．４１ｍｌ／ｇであり、３０ｎｍを越える範囲での細孔容積は０．００１ｍｌ／ｇであった。また、３ｎｍ〜２０ｎｍの範囲での細孔容積は０．３８ｍｌ／ｇであり、２０ｎｍを越える範囲での細孔容積は０．０２７ｍｌ／ｇであった。また、微粒子凝集物のＢＥＴ比表面積は２１５ｍ²／ｇであった。
【０２２６】
次に、本発明の実施例及び比較例で使用するインクサブセット１及び２の作製について説明する。
＜インクサブセット１の作製＞
下記に示す各成分を混合し、十分攪拌して溶解後、ポアサイズが０．４５μｍのフロロポアフィルター（商品名、住友電工（株）製）にて加圧濾過し、ブラック、イエロー、マゼンタ及びシアンの各色の染料インク、Ｂｋ１、Ｙ１、Ｍ１及びＣ１を得、これらの染料インクからなる組み合わせをインクサブセット１とした。
【０２２７】

【０２２８】

【０２２９】

【０２３０】

【０２３１】
＜インクサブセット２の作製＞
下記に示す各成分によって顔料分散液を調製し、これを用いてブラックインクＢｋ２を作製した。更に、色材を代えた以外は上記と同様にして得られた各色の顔料分散液を用いて、イエロー、マゼンタ及びシアンの各顔料インクＹ２、Ｍ２及びＣ２を得た。そして、これらの顔料インクＢｋ２、Ｙ２、Ｍ２及びＣ２からなる組み合わせをインクサブセット２とした。
【０２３２】
［ブラックインクＢｋ２］
（顔料分散液の作製）
・スチレン−アクリル酸−アクリル酸エチル共重合体
（酸価１４０、質量平均分子量５，０００）１．５部
・モノエタノールアミン １．０部
・ジエチレングリコール ５．０部
・イオン交換水 ８１．５部
【０２３３】
上記成分を混合し、ウォーターバスで７０℃に加温し、樹脂分を完全に溶解させる。この溶液に新たに試作されたカーボンブラック（ＭＣＦ８８、三菱化成製）１０部、イソプロピルアルコール１部を加え、３０分間プレミキシングを行った後、下記の条件で分散処理を行った。
・分散機：サンドグラインダー（五十嵐機械製）
・粉砕メディア：ジルコニウムビーズ、１ｍｍ径
・粉砕メディアの充填率：５０％（体積比）
・粉砕時間：３時間
更に、遠心分離処理（１２，０００ｒｐｍ．、２０分間）を行い、粗大粒子を除去して顔料分散液とした。
【０２３４】
（ブラックインクＢｋ２の作製）
上記の顔料分散液を使用し、下記の組成比を有する成分を混合し、顔料を含有するインクを作製し、これをブラックインクＢｋ２とした。
・上記顔料分散液 ３０．０部
・グリセリン １０．０部
・エチレングリコール ５．０部
・Ｎ−メチルピロリドン ５．０部
・エチルアルコール ２．０部
・イオン交換水 ４８．０部
【０２３５】
［イエローインクＹ２］
ブラックインクＢｋ２の調製の際に使用したカーボンブラック（ＭＣＦ８８、三菱化成製）１０部を、ピグメントイエロー７４に代えたこと以外はブラックインクＢｋ２の調製と同様にして、顔料含有イエローインクＹ２を調製した。
【０２３６】
［マゼンタインクＭ２］
ブラックインクＢｋ２の調製の際に使用したカーボンブラック（ＭＣＦ８８、三菱化成製）１０部を、ピグメントレッド７に代えたこと以外はブラックインクＢｋ２の調製と同様にして、顔料含有マゼンタインクＭ２を調製した。
【０２３７】
［シアンインクＣ２］
ブラックインクＢｋ２の調製の際に使用したカーボンブラック（ＭＣＦ８８、三菱化成製）１０部を、ピグメントブルー１５に代えたこと以外はブラックインクＢｋ２の調製と同様にして、顔料含有シアンインクＣ２を調製した。
【０２３８】
（実施例１〜実施例８）
上記のようにして得られた本発明の液体組成物Ａ〜Ｄと、インクサブセット１（Ｂｋ１、Ｙ１、Ｍ１及びＣ１）、及びインクサブセット２（Ｂｋ２、Ｙ２、Ｍ２及びＣ２）の各インクセットを用いて、下記の表２の組み合わせで、印字を行った。これを本発明の実施例１〜８とした。
【０２３９】

【０２４０】
上記のようにして液体組成物Ａ〜Ｄとインクサブセット１及び２を組み合わせて使用する実施例１〜８の着色部の形成方法においては、ＰＰＣ用紙（キヤノン製）に記録を行った。また、その際に使用したインクジェト記録装置としては、図１に示したのと同様の記録装置を用い、図３に示した記録ヘッドを５つ用いてカラー画像を形成した。具体的には、キヤノン製プリンターＢＪＦ８００の改造機を用い、普通紙耐水強化剤のインクタンク内に液体組成物を詰め、各インクは夫々の色に対応するインクタンクに詰めて画像形成を行った。この際、液体組成物を先打ちして先ずＰＰＣ用紙上に付着させ、その後、インクを付着させた。
【０２４１】
そして、印字領域を２回の走査で印字する２パスファイン印字を行って、画像を形成した。このとき、液体組成物は各パス毎に、イエロー、マゼンタ、シアン及びブラックのいずれかのインクが印字される画素位置に印字を行った。即ち、各パス毎のイエロー、マゼンタ、シアン及びブラックの印字データの論理和を液体組成物の印字データとして用いた。尚、ファイン印字時のファインマスクの種類には、特に制限はなく、公知の技術が利用可能であるので、ここでの詳細な説明は省略する。
【０２４２】
ここで用いた記録ヘッドは、６００ｄｐｉの記録密度を有し、駆動条件としては、駆動周波数９．６ｋＨｚとした。６００ｄｐｉのヘッドを使用したときの１ドット当たりの吐出量は、イエロー、マゼンタ、シアンインク及び液体組成物についてはそれぞれ１５ｎｇ、ブラックインクについては１ドット当たり３０ｎｇのヘッドを使用した。尚、これらの記録条件は、実施例及び比較例を通じて同一である。
【０２４３】
（比較例１及び２）
インクサブセット１及び２のみを用いて、下記の表３のようにして印字を行った。

【０２４４】
上記インクサブセット１及びインクサブセット２のみを用いての記録（比較例１及び２）においては、記録ヘッドは６００ｄｐｉの記録密度を有し、駆動条件としては、駆動周波数９．６ｋＨｚとした。６００ｄｐｉの記録ヘッドを使用したときの１ドット当たりの吐出量は、イエロー、マゼンタ及びシアンインクについてはそれぞれ約１５ｎｇ、ブラックインクについては１ドット当たり約３０ｎｇのヘッドを使用し、実施例１〜８の場合と同条件で記録を行った。
【０２４５】
［評価方法及び評価基準］
上記の実施例１〜実施例８、及び比較例１、２で得られたそれぞれの記録画像について、下記の評価方法及び評価基準で評価を行った。表４に、その結果をまとめて示した。
【０２４６】
（記録画像の評価方法）
（１）発色性
高精細ＸＹＺ・ＣＩＥＬＡＢ・ＲＧＢ標準画像（ＳＨＩＰＰ）（監修：高精細標準画像作成委員会、発行：画像電子学会）のＲＧＢカラーチャートをプリンタを用いて印字し、それらのカラーチャートを測色した。発色性の評価は同技術解説書に記載されている方法で色彩分布の３次元的な広がり（以下、文中では色域体積と呼ぶ）の計算を行い、比較した。その際、印字画像を形成する際の画像処理は同一条件とし、測色は、印字後２４時間経過後、ＧＲＥＴＡＧスペクトロリノで光源：Ｄ５０、視野：２°の条件で測定した。その評価基準を以下に示した。インクサブセットのみの印字画像（比較例１及び２）に対しての色域体積の比を、評価基準とした。
【０２４７】
ＡＡＡ：色域体積比が１．７倍以上
ＡＡ：色域体積比が１．５〜１．７倍未満
Ａ：色域体積比が１．４〜１．５倍未満
ＢＢ：色域体積比が１．２〜１．４倍未満
Ｂ：色域体積比が１．０〜１．２倍未満
Ｃ：色域体積比が１．０倍未満
【０２４８】
尚、これとは別に、インクジェット用コート紙（商品名：カラーＢＪ用紙ＬＣ−１０１、キヤノン（株）製）を用いてインクサブセット１で印字して画像を形成し、上記の比較例１の印字物との色域体積の比を求めたところ、１．３倍であった。
【０２４９】
（２）均一性
前記したプリンタを用いて、イエロー、マゼンタ、シアン及びブラック各色のインクのベタ画像を印字した後、目視にて、白モヤと色ムラに関して色の均一性を評価した。この際、特に均一性の悪い色を評価対象とした。評価基準は、以下の通りである。
Ａ：白モヤや色ムラは殆ど発生しない。
Ｂ：若干紙の繊維に沿って白モヤや色ムラが見えるが、実質上問題のないレベルである。
Ｃ：紙の繊維に沿って著しく白モヤや色ムラが見える。
【０２５０】
（３）スジムラ
前記したプリンタを用いて、イエロー、マゼンタ、シアン及びブラック各色のインクのベタ画像を印字した後、目視にて、スジムラを評価した。この際、特にスジムラの悪い色を評価対象とした。評価基準は以下の通りである。
Ａ：スジムラは殆ど発生しない。
Ｂ：若干ヘッドスキャン毎のスジムラが見えるが、実質上問題のないレベルである。
Ｃ：著しくヘッドスキャン毎の白いスジムラが見える。
【０２５１】
（４）風合い
前記したプリンタを用いて、イエロー、マゼンタ、シアン及びブラック各色のインクのベタ画像を印字した後、目視にて被記録媒体の風合いを評価した。評価基準は、以下の通りである。
Ａ：印字部及び未印字部が共に違和感がなく普通紙の風合いを残している。
Ｂ：印字部と未印字部で風合いが異なる、又は記録媒体全体が普通紙の風合いと大きく異なる。
【０２５２】
（５）ブリード
前記したプリンタを用いて、シアンとブラックのベタ画像を隣接して印字した後、色間境界部のブリードを目視で観察し、下記の基準で評価した。
ＡＡ：ブリーディングを視認できない。
Ａ：ブリーディングは殆ど目立たない。
Ｂ：ブリーディングはしているが、実質上問題のないレベルである。
Ｃ：色の境界紙がハッキリしない程、ブリーディングしている。
【０２５３】
（６）文字品位
前記したプリンタを用いてブラックのテキストを印字し、文字品位の程度を目視により観察した。評価基準は以下の通りである。
Ａ：シャープにテキストが再現され、フェザリングや文字太りが殆ど発生しないもの。
Ｂ：ややフェザリングが発生するが、実質上問題のないレベルである。
Ｃ：上記以外のもの。
【０２５４】

【０２５５】
（実施例９〜１５）
使用する被記録媒体の種類による画像品質への影響を調べるため、上記で作成した液体組成物Ｂとインクサブセット１とを用いて、下記１）〜７）の商品名で広く流通している７種類の「普通紙」を用い、これらの普通紙上で、インクサブセット１を構成する４色のインク各々と該液体組成物Ｂとを上記実施例と同様に印字して実施例９〜１５の記録画像を形成した。この画像を、上記した評価基準に基づき評価した。得られた結果を下記の表５に示した。
【０２５６】
被記録媒体
１）キヤノン社製：ＰＢ用紙
２）キヤノン社製：Brilliant Whitepaper
３）Union Camp社製：Great White Inkjet
４）ハンマーミル（Hammermill）社製：JetPrint
５）ゼロックス（Xerox）社製：Xerox ４０２４
６）ヒューレットパッカード（Hewlett Packard）社製：Bright White Inkjet Paper
７）AussdatRay社製：RayJet
【０２５７】

【０２５８】
以上の結果、実施例９〜１５の着色部の形成方法においては、表５に示されているように、被記録材の種類によらず、発色性や均一性に優れ、スジムラやブリードの発生が抑制され、更には、風合いや文字品位のいずれにおいても満足できる画像が得られることが確認できた。
【０２５９】
【発明の効果】
以上説明したように、本発明によれば、特に、普通紙に対するカラーインクジェット記録を行った場合に、普通紙の風合いを残しながらインクジェット用コート紙並みの優れた発色性と色の均一性、及び色境界部でのブリードの発生が抑制された文字品位に優れ、且つベタ画像部のスジムラが少ないインクジェット記録画像が得られる液体組成物、インクセット、被記録媒体に着色部を形成する方法及びインクジェット記録装置が提供される。しかも、本発明によれば、保存安定性や記録ヘッドからの吐出安定性にも優れたインクジェット記録特性に優れる液体組成物が提供される。
【図面の簡単な説明】
【図１】本発明を適用したインクジェットプリンタを模式的に示す一部破断斜視図。
【図２】図１中のヘッドカートリッジの模式的斜視図。
【図３】図１中のヘッドカートリッジのインク吐出部の構造を模式的に示す部分斜視図。
【図４】図１のインクジェットプリンタのワイピング動作を示す模式図であり、（Ａ）は各ヘッドのプリント領域側からホームポジションへの移動とインク用ブレードの上昇、（Ｂ）はプリントヘッドのワイピング、（Ｃ）は液体組成物吐出ヘッドのワイピング、（Ｄ）は各ブレードの下降をそれぞれ示す。
【図５】図１のインクジェットプリンタのワイピング動作を示す模式図であり、（Ａ）は各ブレードの上昇、（Ｂ）は各ヘッドのホームポジションからプリント領域側への移動、（Ｃ）は液体組成物用ブレードの下降、（Ｄ）はプリントヘッドのワイピングとインク用ブレードの下降をそれぞれ示す。
【図６】図１のインクジェットプリンタのワイピング動作を示す模式図であり、（Ａ）はインク用ブレードの上昇、（Ｂ）は各ヘッドのホームポジション側からプリント領域側への移動とプリントヘッドのワイピング、（Ｃ）は各ヘッドのプリント領域側からホームポジション側への移動とインク用ブレードの待機と液体組成物用ブレードの上昇、（Ｄ）各ヘッドのホームポジション側への移動と液体組成物吐出ヘッドのワイピングをそれぞれ示す。
【図７】図１のインクジェットプリンタの廃液回収系統を示す模式図。
【図８】図７の廃液回収系統の一部変更例を示す模式図。
【図９】コート紙にインクジェット記録を行なったときの着色部の状態を説明する模式的断面図。
【図１０】本発明にかかるインクカートリッジの一実施態様を示す概略図。
【図１１】図１０のインクカートリッジを装着した記録ヘッドの概略図。
【図１２】本発明にかかる記録ユニットの一実施態様を示す概略図。
【図１３】本発明にかかるインクジェット画像の着色部の状態を説明する模式的断面図。
【図１４】本発明にかかるインクジェット記録画像の着色部の形成工程を示す概略工程図。
【図１５】記録ユニットの斜視図。
【図１６】本発明にかかるインクジェットプリンタの一つの実施態様を模式的に示す一部破断斜視図である。
【図１７】図１６のインクジェットプリンタのワイピング動作を示す模式図であり、（Ａ）はインク用ブレードの上昇、（Ｂ）はプリントヘッドのワイピング、（Ｃ）はインク用ブレードの下降、（Ｄ）は液体組成物が適正位置についた後の両ブレードの上昇、（Ｅ）は液体組成物と第２のブラックインク用ヘッドのワイピング、（Ｆ）は両ブレードの下降をそれぞれ示す。
【符号の説明】
１：プリント用ヘッドカートリッジ）
２：液体組成物用ヘッドカートリッジ
３：キャリッジ
４：ガイド軸（走査レール）
５：駆動ベルト
６、７：搬送ローラ
８、９：搬送ローラ
１０：被記録媒体
１１：回復ユニット
１２：キャップ（インク用）
１３：キャップ（液体組成物用）
１４：吸引ポンプ（インク用）
１５：吸引ポンプ（液体組成物用）
１６：ブレード（インク用）
１７：ブレード（液体組成物用）
１８：ブレードホルダー（ブレード１６用）
１９：ブレードホルダー（ブレード１７用）
２１：液貯留タンク部
２２：（インク）吐出部
２２Ａ：（液体組成物）吐出部
２３：ヘッド側コネクタ
２４：廃液タンク
２５：吸収体
２５Ａ：インク吸収体
２５Ｂ：液体組成物吸収体
２６：廃インク導管
２７：廃液導管
８１：吐出口形成面
８２：吐出口
８３：共通液室
８４：液路
８５：電気熱変換体（発熱抵抗体等）
９０１：基紙
９０３：インク受容層
９０５：多孔質微粒子
９０７：接着剤
９０９：インク浸透部
１００１：カートリッジ
１００３：インク収容部
１００５：液体組成物収容部
１１０１：記録ヘッド
１２０１：記録ユニット
１２０１Ｙ：イエローインク収容部
１２０１Ｍ：マゼンタインク収容部
１２０１Ｃ：シアンインク収容部
１２０１Ｌ：液体組成物収容部
１２０１Ｂｋ：ブラックインク収容部
１２０３：記録ヘッド
１３０１：被記録媒体
１３０２：被記録媒体の繊維間の空隙
１３０３：微粒子
１３０５：色材
１３０７：（色材を保持する）微粒子の凝集物
１３０９：（被記録媒体の繊維付近の）微粒子の凝集物
Ｉ：着色部
ＩＭ：主画像部
ＩＳ：周辺部
１４００：着色部
１４０１：反応部
１４０２：インク流出部
１４０３：被記録媒体
１４０４：色材
１４０５：被記録媒体の繊維間の空隙
１４０６：液体組成物
１４０７：液溜り
１４０９：微粒子
１４１１：微粒子同士の集まり
１４１３：インク
１４１５：色材が付着した微粒子の凝集物
１５００：記録ユニット
１５０１：ヘッド部
１５０２：大気連通孔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for obtaining an excellent image with high color developability and color uniformity in color image formation, improved bleed and improved character quality, and particularly suitable for image formation using an ink jet recording system. Liquid composition, ink set that can be used for as well as How to form colored parts on the recording medium To the law Related.
[0002]
[Prior art]
The ink jet recording method performs recording by flying ink and attaching the ink to a recording medium such as paper. For example, as disclosed in JP-B-61-59911, JP-B-61-59912 and JP-B-61-59914, an electrothermal converter is used as a discharge energy supply means, and heat energy is applied to the ink. According to the ink jet recording method of discharging droplets by generating bubbles, it is possible to easily realize a high-density multi-orifice of the recording head and to record a high-resolution and high-quality image at high speed. Can do.
[0003]
By the way, the ink used in the conventional ink jet recording method is mainly composed of water and a coloring material, and water-soluble high boiling point such as glycol for the purpose of preventing the ink from drying in the nozzle and preventing clogging of the nozzle. Those containing a solvent are generally used. Therefore, when recording is performed on a recording medium using such an ink, sufficient fixability cannot be obtained, or due to uneven distribution of fillers and sizing agents on the surface of the recording paper as the recording medium. May cause problems such as the generation of non-uniform images. On the other hand, in recent years, there has been a strong demand for ink jet recordings to have the same high image quality as that of silver halide photographs, increasing the image density of the ink jet recording image, expanding the color reproduction area, Technical requirements for improving the color uniformity of recorded matter are very high.
[0004]
Under such circumstances, various proposals have been made so far in order to stabilize the ink jet recording method and improve the quality of the recorded matter by the ink jet recording method. As one of proposals regarding the recording medium, a method of applying a filler or a sizing agent to the surface of the base paper of the recording medium has been proposed. For example, a technique is disclosed in which porous fine particles that adsorb a coloring material as a filler are coated on a base paper, and an ink receiving layer is formed by the porous fine particles. Inkjet coated paper and the like are commercially available as recording media using these techniques.
[0005]
Under such circumstances, various proposals have been made so far in order to stabilize the ink jet recording method and improve the quality of the recorded matter by the ink jet recording method. Some of the typical ones are classified and summarized below.
(1) A method of internally adding a volatile solvent or a penetrating solvent to the ink;
Japanese Patent Application Laid-Open No. 55-65269 discloses a method of adding a compound that enhances permeability such as a surfactant into the ink as means for accelerating the fixability of the ink on the recording medium. Japanese Patent Application Laid-Open No. 55-66976 discloses the use of an ink mainly composed of a volatile solvent.
[0006]
(2) A method in which a liquid composition that reacts with ink is mixed with ink on a recording medium;
For the purpose of improving image density, improving water resistance, and suppressing bleeding, a liquid composition that makes an image good before or after jetting ink for forming a recorded image is formed on the recording medium. A method of granting has been proposed. For example, Japanese Patent Application Laid-Open No. 63-60783 discloses a method in which a liquid composition containing a basic polymer is attached to a recording medium and then recorded with an ink containing an anionic dye. Japanese Laid-Open Patent Publication No. 63-22681 discloses a recording method in which a first liquid composition containing a reactive chemical species and a second liquid composition containing a compound that reacts with the reactive chemical species are mixed on a recording medium. Further, Japanese Patent Application Laid-Open No. 63-299971 discloses an anion after applying a liquid composition containing an organic compound having two or more cationic groups per molecule on a recording medium. A method of recording with an ink containing a dye is disclosed. Japanese Patent Application Laid-Open No. 64-9279 discloses a method of recording with an ink containing an anionic dye after applying an acidic liquid composition containing succinic acid or the like onto a recording medium.
[0007]
Japanese Patent Application Laid-Open No. 64-63185 discloses a method in which a liquid composition that insolubilizes a dye is applied to paper prior to application of ink. Further, JP-A-8-224955 discloses a method of using a liquid composition containing cationic substances having different molecular weight distribution regions together with an ink containing an anionic compound, and JP-A-8-72393 discloses. Discloses a method of using a liquid composition containing a cationic substance and finely pulverized cellulose together with ink, all of which have high image density, good print quality and water resistance, and good color reproducibility and bleeding. It is described that an image can be obtained. Japanese Patent Application Laid-Open No. 55-150396 discloses a method of applying a water-proofing agent that forms a dye and a rake after recording with a dye ink on a recording medium, and imparts water resistance to a recorded image. It has been proposed.
[0008]
(3) A method of mixing ink and a fine particle-containing liquid composition on a recording medium;
Japanese Laid-Open Patent Publication No. 4-259590 discloses a method for applying a non-aqueous recording liquid after applying a colorless liquid containing colorless fine particles made of an inorganic substance onto a recording medium. Discloses a method of applying an ink containing a pigment, a water-soluble resin, a water-soluble solvent and water after applying a solution containing fine particles or a solution containing fine particles and a binder polymer onto a recording medium. Japanese Patent No. 2000-34432 discloses a recording material containing a liquid composition composed of water-insoluble fine particles and an ink, and any of them can provide an image with good print quality and color developability regardless of the type of paper. Is described.
[0009]
As a result of studying various ink jet recording techniques as described above, the present inventors can confirm excellent effects for each technical problem, but in exchange for this, other ink jet recording characteristics are reduced. I found out that it might end up.
[0010]
For example, a recording medium (hereinafter referred to as coated paper) obtained by applying a filler or a sizing agent on the surface of a base paper of the recording medium is recognized as a technique capable of forming a high-quality image. In general, in order to obtain a high-saturation image, it is known that it is necessary to leave the coloring material on the surface of the recording medium in a monomolecular state without aggregating the coloring material. Fine particles have such a function. However, in order to obtain higher image density and image saturation, it is indispensable to form a thick ink-receiving layer that covers the base paper with a large amount of porous fine particles for the color material in a given ink. As a result, the coated paper has another problem that the texture of the base paper is lost. The present inventors need the ink receiving layer so as to lose the texture of the base paper because the coloring material in the ink is not efficiently adsorbed to the porous fine particles. I guessed.
[0011]
A description will be given below assuming a coated paper having one ink-receiving layer. FIG. 9 schematically shows a cross section near the surface of the coated paper. In the figure, reference numeral 901 denotes a base paper, and reference numeral 903 denotes an ink receiving layer. In general, the ink receiving layer 903 includes porous fine particles 905 and an adhesive 907 that fixes them. When the ink is applied, the ink permeates the gap between the porous fine particles 905 by capillary action to form an ink permeation portion 909. As shown in the figure, since the porous fine particles 905 in the ink receiving layer have locally different densities, the manner of ink penetration by this capillary phenomenon varies depending on the location. For this reason, in the ink permeation step, the color material cannot uniformly contact the surface of the porous fine particles, and the color material is not efficiently adsorbed by the porous fine particles.
[0012]
Further, there is a portion where the ink penetration is hindered by the adhesive 907, and there is a portion where the ink cannot permeate in the ink receiving layer 903, and a portion which does not contribute to color generation occurs. That is, in the conventional coated paper, the coloring material cannot be efficiently adsorbed in a monomolecular state with respect to the amount of the porous fine particles due to the reasons described above, and as a result, a high quality image is obtained. For this purpose, a large amount of porous fine particles 905 are required, which impairs the texture of the base paper.
[0013]
Further, according to the study by the present inventors, by adopting the technique (1) described above, although the fixing property of the ink to the recording medium is improved, the image density is lowered and the recording on the plain paper is performed. It has been found that the color reproduction range, which is important for recording color images, may decrease. Further, according to the study by the present inventors, according to the technique (2) described above, since the coloring material in the ink can be retained on the surface of the recording medium, a recorded matter with a high image density can be obtained. However, the color reproduction range and saturation may not be sufficiently obtained because the color material is aggregated on the surface of the recording medium. In the prior art described in (3) above, although the surface condition of the recording medium was improved by applying a solution containing fine particles, a high-definition image equivalent to that of coated paper was obtained. Absent. Furthermore, particularly with respect to non-aqueous recording liquids, there are limitations on the selectivity of the color material, the method of applying the recording, and the like, and there remains a problem with the degree of freedom. As described above, since all of the conventional methods still have problems, the present inventors have developed a new ink jet recording technique for the higher quality ink jet recorded material that has been demanded in recent years. It came to recognition that development of was necessary. The present invention has been made based on these recognitions.
[0014]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a liquid composition that is used to obtain a high-quality inkjet recording material having a wider color reproduction range, excellent color uniformity, suppressed bleeding, and excellent character quality. To provide things.
Another object of the present invention is to provide an excellent inkjet recording product having a wider color reproduction range, excellent color uniformity, suppressed bleeding, excellent character quality, and less unevenness of solid portions. Another object of the present invention is to provide a method of forming a colored portion on a recording medium that can be formed on plain paper.
Another object of the present invention is that the color reproduction range is further widened, the color uniformity is excellent, the occurrence of bleeding is suppressed, the character quality is excellent, and the occurrence of uneven stripes in the solid portion is suppressed to a good state. Inkjet recordings can be formed Liquid The object is to provide a body composition and an ink set.
Furthermore, another object of the present invention is to provide a liquid composition having excellent ink jet recording characteristics such as storage stability and ejection stability from a recording head.
[0015]
[Means for Solving the Problems]
According to one embodiment of the present invention, an anion containing a coloring material Sex A liquid composition that is applied to a recording medium together with a water-based ink (except when it contains resin emulsion particles) and is used to form a colored portion on the recording medium. The surface is charged with a polarity opposite to that of at least the solvent and the water-based ink, and has reactivity with the colorant. Alumina hydrate Fine particles With child And a specific surface area determined by measuring by BET nitrogen adsorption / desorption method for a fine particle aggregate formed from the liquid composition according to the following steps (1) to (4): ² A liquid composition is provided that is characterized by / g.
(1) A step of drying the liquid composition at 120 ° C. for 10 hours in an air atmosphere;
(2) The temperature of the dried product is raised to 120 to 700 ° C. over 1 hour and then calcined at 700 ° C. for 3 hours;
(3) A step of gradually cooling the fired product obtained in the step (2) to room temperature and then pulverizing it; and
(4) A step of obtaining a fine particle aggregate by vacuum degassing the powder obtained in (3) above at 120 ° C. for 8 hours.
[0016]
In addition, according to another embodiment of the present invention, a coloring material is included. Anionic An ink set comprising an ink and a liquid composition containing fine particles having reactivity with the coloring material independently, wherein the liquid composition is the liquid composition described above is provided Is done.
According to another embodiment of the present invention, the recording target includes the step (i) of applying an ink containing a coloring material to a recording medium and the step (ii) of applying a liquid composition to the recording medium. A method for forming a colored portion on a medium, wherein each of the ink and the liquid composition is an ink and a liquid composition constituting the ink set described above. A method of forming is provided.
A preferred embodiment of a method for forming a colored portion on a recording medium is as described above.
1) Method for forming a colored portion on a recording medium to be subjected to step (i) after performing step (ii)
2) Method for forming a colored portion on the recording medium to be subjected to step (ii) after performing step (i)
Is mentioned.
[0018]
As a result of intensive studies to solve the above-described problems of the prior art, the present inventors have used fine particles having an action of adsorbing a color material in a monomolecular state and efficiently adsorbing the color material to the fine particles. By dispersing the fine particles in a solvent for bonding and using them together with ink in a liquid state, it is possible to cause the color material and the fine particles to react in a liquid-liquid state. As a result, the density and saturation of the image can be reduced. The inventors have found that it can be improved with high reliability, and have reached the present invention.
[0019]
In this specification, “reaction” in “fine particles having reactivity with color material” or “reaction between color material and fine particles” refers to ionic bonds, physical bonds in addition to covalent bonds between color materials and fine particles. -It shall mean chemical adsorption, absorption, adhesion and other interactions.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments.
As described above, the liquid composition according to one embodiment of the present invention includes an anion containing a coloring material. Sex A liquid composition that is applied to a recording medium together with a water-based ink (except when it contains resin emulsion particles) and is used to form a colored portion on the recording medium. The surface is charged with a polarity opposite to that of at least the solvent and the water-based ink, and has reactivity with the colorant. Alumina hydrate Fine particles With child And a specific surface area determined by measuring by BET nitrogen adsorption / desorption method for a fine particle aggregate formed from the liquid composition according to the following steps (1) to (4): ² / G.
(1) A step of drying the liquid composition at 120 ° C. for 10 hours in an air atmosphere and substantially evaporating the solvent to dry;
(2) The temperature of the dried product is raised to 120 to 700 ° C. over 1 hour and then calcined at 700 ° C. for 3 hours;
(3) A step of gradually cooling the fired product obtained in the step (2) to room temperature and then pulverizing it; and
(4) A step of vacuum degassing the powder obtained in (3) above at 120 ° C. for 8 hours to obtain fine particle aggregates formed from the liquid composition.
[0021]
As a preferred embodiment of a method for forming a colored portion on a recording medium using such a liquid composition, the step (i) of applying an ink containing a coloring material to the recording medium and the liquid composition described above are used. And a step (ii) of applying to a recording medium, and the ink and the liquid composition are applied so as to be in contact with each other in a liquid state on the surface of the recording medium. By adopting such an embodiment, the ink jet recording has an even wider color reproduction area, color uniformity, occurrence of bleeding, excellent character quality, and less unevenness of solid portions. A thing is obtained stably.
[0022]
Furthermore, one embodiment of the ink set according to the present invention that can achieve the above object includes a combination of an ink containing a coloring material and the above liquid composition. By using the ink set of such an embodiment, inkjet recording having a wider color reproduction region, color uniformity, occurrence of bleeding, excellent character quality, and less solid stripes A thing is obtained stably. In the present invention, since the ink used for recording and the liquid composition itself used in combination with the ink have a very simple configuration as described above, both the ink and the liquid composition have excellent storage stability. As a result, there is also an effect that it is possible to stably perform image formation from which a high-quality ink jet recorded matter can be obtained.
[0023]
Although the reason why the above-described excellent effect is achieved by the present invention is not clear, the present inventors consider that the reason is as follows. That is, the present inventors have heretofore provided an image forming method using an ink set comprising an ink containing a color material and a liquid composition containing fine particles having reactivity with the color material. The mechanism by which the fine particle aggregates are formed on the surface of the recording medium or on the surface and the vicinity thereof when mixed above has been studied.
[0024]
First, the mechanism will be described more specifically with reference to FIGS. In this case, an aqueous ink containing a water-soluble dye having an anionic group (anionic dye) is used as the ink, and the liquid composition combined therewith contains fine particles whose surfaces are cationically charged in a dispersed state. The case where the aqueous liquid composition currently used is used is demonstrated.
[0025]
Prior to the explanation, define the words. The “monomolecular state” used in the following description means that a color material such as a dye or a pigment is almost kept dissolved or dispersed in the ink. At this time, even if the color material causes some aggregation, it is included in the “monomolecular state” as long as the saturation does not fall. For example, in the case of a dye, it is considered that it is preferably a single molecule, and therefore, for the sake of convenience, a color material other than a dye is also referred to as a “single molecule state”.
[0026]
FIG. 13 is a schematic cross-sectional view schematically showing a state in which the colored portion I of the recorded image formed based on the above mechanism is composed of the main image portion IM and its peripheral portion IS. In FIG. 13, reference numeral 1301 denotes a recording medium, and 1302 denotes a gap generated between fibers of the recording medium. Reference numeral 1303 schematically shows fine particles that the colorant 1305 chemically adsorbs. As shown in FIG. 13, in the ink jet recording image obtained by the present invention, the main image portion IM has the color material 1305 in a monomolecular state or a state close to this state (hereinafter referred to as “monomolecular state”). It is composed of fine particles 1303 that are uniformly adsorbed on the surface and fine particle aggregates 1307 that maintain the monomolecular state of the coloring material. Reference numeral 1309 denotes an aggregate of fine particles present in the vicinity of the recording medium fiber in the main image portion IM. Such a main image portion IM is formed by a process in which the fine particles 1303 are physically or chemically adsorbed on the recording medium fiber and a process in which the coloring material 1305 and the fine particles 1303 are adsorbed in a liquid-liquid state. For this reason, the coloring characteristics of the color material itself are rarely impaired, and even on a recording medium such as plain paper where the ink is likely to sink, the image density and saturation are high, and the image has a wide color reproduction range similar to that of coated paper. Formation is possible.
[0027]
On the other hand, the coloring material 1305 that is not adsorbed on the surface of the fine particles 1303 and remains in the ink penetrates the recording medium 1301 both in the lateral direction and in the depth direction. Form. In this way, the color material remains in the vicinity of the surface of the recording medium 1301, and in order to form a slight blur of ink in the peripheral portion, even in an image region having a large amount of ink applied such as a shadow portion or a solid portion, In addition, an image with little color unevenness and excellent color uniformity is formed. As shown in FIG. 13, in the case where the recording medium 1301 has the permeability of the ink or the liquid composition, this aspect allows the penetration of the ink component or the liquid composition component into the recording medium. Is not necessarily impeded, but tolerate some degree of penetration.
[0028]
Furthermore, when the fine particle aggregate 1309 existing near the surface of the recording medium is formed by the reaction with the color material in the ink, the liquid composition has pores of a certain size inside the aggregate. Is formed. The color material 1305 that has been present alone in the ink penetrates into the pores of the fine particle aggregate 1309 when the ink penetrates into the recording medium, and near the entrance of the pores. In other words, the coloring material is adsorbed to the inner wall in an ideal single molecule state, so that more coloring material remains near the surface of the recording medium. As a result, it is possible to obtain a recorded matter having even more excellent color developability.
[0029]
As a result of further studies on this mechanism, the present inventors have found that the specific surface area of the aggregate has an influence on the existence state of the color material in the recording portion, and the specific surface area of the aggregate. As a result, it was recognized that the existence state of the color material in the recording portion can be controlled more accurately, and as a result, a higher quality recorded matter can be formed. However, in the examination process for obtaining a preferable value of the specific surface area, it was extremely difficult to obtain the specific surface area of the aggregate from the actual recorded matter. This is because the color material is adsorbed to the surface and pores of the actual aggregate. In view of this, the present inventors have studied various methods for defining the specific surface area of the fine particle aggregate having a correlation with the quality of the recording portion. As a result, the value of the specific surface area obtained by the BET nitrogen adsorption / desorption method correlates with the higher-quality ink image with respect to the fine particle aggregate obtained according to the following procedures (1) to (4). I found that I have.
[0030]
Specifically, the specific surface area value obtained by the following procedures (1) to (4) is 70 to 250 m. ² / G, it was found that an extremely high-quality recording part can be formed. The present invention has been made based on such novel findings of the present inventors.
(1) A step of drying the liquid composition at 120 ° C. for 10 hours in an air atmosphere;
(2) A step of heating the dried product obtained in (1) above to 120 to 170 ° C. over 1 hour and then baking at 700 ° C. for 3 hours;
(3) The step of allowing the fired product obtained in (2) above to cool to room temperature (25 ° C.) and then pulverizing using, for example, an agate mortar;
(4) A step of obtaining a fine particle aggregate by vacuum degassing the powder obtained in (3) above at 120 ° C. for 8 hours.
[0031]
The pulverization in the above step (3) is an operation for improving workability, and this operation does not affect the specific surface area value obtained by the BET nitrogen adsorption / desorption method to be performed thereafter. Absent. That is, the specific surface area of the fine particle aggregate does not change before and after this operation. In the liquid composition of the present invention, since the specific surface area of the fine particle aggregate 1309 formed as described above has a size within the specific range described above, the liquid composition of the present invention is image-formed. When it is used, the adsorption site of the color material component increases, and the reactivity with the color material is improved. As a result, the occurrence of bleed at the color boundary portion is suppressed while the fine blur is formed as described above, and the character quality is improved even on a recording medium such as plain paper which is likely to cause feathering. The effect of is obtained.
[0032]
14 (1) to 14 (4) are schematic cross-sectional views illustrating a colored portion 1400 showing an embodiment of a method for forming a colored portion on a recording medium according to the present invention, and a forming step of the colored portion. It is a schematic diagram. In FIG. 13, reference numeral 1401 denotes a part mainly containing a reaction product of ink and a liquid composition, for example, a reaction product of a coloring material and fine particles (hereinafter abbreviated as “reaction part”). It is a part corresponding to. Reference numeral 1402 denotes a portion (hereinafter, abbreviated as “ink outflow portion”) formed by the ink that has not substantially participated in the reaction with the liquid composition flowing out to the edge of the reaction portion 1401. It corresponds to the peripheral part IS. The colored portion 1400 is formed as follows, for example. Note that reference numeral 1405 shown in FIG. 14A schematically represents a gap generated between fibers of the recording medium. As described below, according to the method for forming a colored portion on the recording medium according to the present invention using the liquid composition of the present invention, the image density is much higher than that of the conventional one, and the coloring portion is colored. Highly recorded material can be obtained stably, and this reason is considered to have been achieved as a result of the following mechanisms.
[0033]
First, as shown in FIG. 14 (1), when the liquid composition 1406 having fine particles 1409 having reactivity with the coloring material is applied as droplets to the recording medium 1403, it is shown in FIG. 14 (2). As described above, the liquid composition pool 1407 is formed on the surface of the recording medium. In the liquid reservoir 1407, fine particles 1409 near the fiber surface of the recording medium 1403 are physically or chemically adsorbed on the fiber surface of the recording medium. At this time, it is considered that there are some which become unstable in a dispersed state and form an aggregate 1411 of fine particles. On the other hand, it is considered that the fine particles 1409 maintain the original uniform dispersion state in a portion away from the fibers in the liquid reservoir 1407.
[0034]
Next, as shown in FIG. 14 (2), when the ink 1413 having the color material 1404 is applied as a droplet to the recording medium 1403, first, at the interface between the ink 1413 and the liquid reservoir 1407, The color material 1404 is chemically adsorbed to the fine particles 1409 (see FIG. 14 (3)). Since this reaction is a liquid-liquid reaction (liquid-liquid reaction), as shown in FIG. 14 (3) -2, it is considered that the coloring material 1404 is in a single molecule state and is uniformly adsorbed on the surface of the fine particles 1409. It is done. That is, it is presumed that the color materials 1404 do not aggregate on the surface of the fine particles 1409 or are slightly aggregated. As a result, a large number of fine particles 1409 in which the color material 1404 is adsorbed in a monomolecular state are formed on the surface layer portion of the reaction portion 1401. As a result, since the color material 1404 remains in a monomolecular state on the surface layer that most affects the color development of the image, the formed image has a high image density and high saturation. Become.
[0035]
Further, the fine particles 1409 on which the coloring material 1404 is adsorbed on the surface are considered to be aggregated among the fine particles because the dispersion state becomes unstable. Here, as shown in FIG. 14 (3) -2, the formed agglomerate 1415 holds the color material 1404 in a monomolecular state therein. Due to the presence of the agglomerates 1415, the method for forming a colored portion on the recording medium of the present invention makes it possible to form a recorded image with higher image density and higher saturation.
[0036]
Further, a part of the unreacted color material 1404 diffuses in the liquid reservoir 1407 and is adsorbed on the surface of the unreacted fine particles 1409. In this manner, the reaction between the color material 1404 and the fine particles 1409 further proceeds in the liquid reservoir 1407, so that an image with higher density and higher saturation is formed. On the other hand, it is considered that the fine particle aggregate 1411 formed on the fiber surface of the recording medium 1403 described above has a role of suppressing the penetration of the liquid phase of the liquid reservoir 1407 into the recording medium. For this reason, in the liquid reservoir 1407, the fine particles 1409 and the color material 1404 in the liquid composition in which the permeation is suppressed can be mixed more. As a result, the contact probability between the color material 1404 and the fine particles 1409 is increased. The reaction proceeds relatively uniformly and sufficiently. As a result, it is possible to form an image that is more uniform and excellent in image density and saturation.
[0037]
Further, when the liquid composition 1406 shown in FIG. 14 (1) is applied to the recording medium 1403, or when the ink 1413 is applied to the liquid composition reservoir 1407 shown in FIG. 14 (2). In some cases, dispersion of the fine particles 1409 becomes unstable due to a change in the dispersion medium in which the fine particles 1409 are dispersed, and aggregation occurs between the fine particles 1409 before the coloring material 1404 is adsorbed. The change of the dispersion medium here means a change generally observed when two or more kinds of different liquids are mixed, for example, pH of the liquid phase, solid content concentration, liquid medium (solvent) composition, This refers to changes in physical properties such as the concentration of dissolved ions. When the liquid composition comes into contact with the recording medium or ink, these changes occur suddenly and complexly, destroying the dispersion stability of the fine particles, and generating an aggregate 1415 It is thought to do. These agglomerates 1415 are presumed to bring about an effect of filling the gaps between the fibers and an effect of leaving the fine particles 1409 adsorbing the coloring material 1404 more in the vicinity of the surface of the recording medium 1403.
[0038]
Further, the agglomerate 1415 formed in the liquid reservoir 1407 may be adsorbed on the recording medium 1403 or may be movable (has fluidity) in the liquid phase, but the fluidity is low. In the same manner as in the reaction step between the color material 1404 and the fine particles 1409 described above, the color material is adsorbed on the surface of the fine particle aggregate 1415 in a monomolecular state to form larger aggregates. And this is considered to have contributed to the improvement of color development. That is, this large agglomerate moves with the liquid phase as it penetrates along the fibers, fills the gap and smoothes the surface of the recording medium 1403, and contributes to the formation of a more uniform and high-density image. It is thought to do.
[0039]
Although it is clear from the results described later that an image having a very high density and high color can be obtained by the present invention as compared with the conventional one, as described above, When the liquid composition and the liquid composition are both applied to the recording medium, the color material 1404 in the ink is adsorbed in a monomolecular state to the fine particles 1409 or the fine particle aggregates 1415 that are constituents of the liquid composition. This is presumably because it remains in the vicinity of the surface of the recording medium 1403. Further, since the coloring material is adsorbed in a monomolecular state and the fine particles remaining in the vicinity of the surface of the recording medium are fixed on the surface of the recording medium in this state, the scratch resistance, water resistance, etc. of the formed image are reduced. Robustness is also improved.
[0040]
In the above description, the case where the liquid composition and the ink are applied to the recording medium has been described. However, if the liquid-liquid reaction between the ink and the liquid composition is achieved, the ink and the liquid composition The order in which the recording media are assigned to the recording medium is not limited. Therefore, the order of applying the ink and then applying the liquid composition may be used.
[0041]
Furthermore, as shown in FIG. 14 (2), at least a part of the fine particles 1409 in the liquid composition applied to the recording medium is contained in the recording medium of the liquid medium that is a component of the liquid composition. It is considered that the recording medium 1403 penetrates with the penetration. On the other hand, as clearly shown in FIG. 14 (4), it can be sufficiently assumed that the coloring material 1404 is adsorbed or bonded in a monomolecular state to the fine particles 1409 that have penetrated previously. As described above, it is considered that the fine particles 1409 in which the coloring material 1404 is adsorbed or bonded in a monomolecular state inside the recording medium also contributes to the improvement of color development. Further, it is considered that the fixability of the ink is improved by such penetration of the liquid medium.
[0042]
Further, when the fine particle aggregate 1411 existing near the surface of the recording medium is formed by using the liquid composition of the present invention, pores having a certain size are formed inside the aggregate. It is formed. In the liquid reservoir 1407, the color material 1404 that could not be adsorbed by the fine particles 1409 penetrates into the recording medium 1403, along with the liquid medium component, through the pores and inside the fine particle aggregate 1411. Some of them penetrate into. At that time, the coloring material 1404 adsorbs to the vicinity of the entrance of the pores in the fine particle aggregates or the inner wall of the fine pores, and only the solvent component permeates into the recording medium 1403, thereby increasing the coloring material in a larger amount. It can be efficiently adsorbed on the surface and the inside of the aggregate 1411 and can remain in the vicinity of the surface of the recording medium. Further, when the coloring material 1404 is a dye, the fine particle aggregate 1411 has a pore diameter of about 1 to several times the molecular size present in the ink of the coloring material 1404, and is therefore adsorbed inside the pores. The color material 1404 is extremely unlikely to aggregate between the color materials, and can form an ideal monomolecular state. This greatly contributes to the further improvement of color developability and makes it possible to obtain a recorded matter having a wider color reproduction range.
[0043]
Further, the fine particle aggregate 1411 is considered to be substantially fixed with the fluidity being remarkably reduced in the vicinity of the surface of the recording medium, and the color material component adsorbed on the surface of the fine particle aggregate and inside the pores is It tends to be difficult to move inside the liquid reservoir 1407. According to the study by the present inventors, when the specific surface area of the fine particle aggregate 1411 has a specific size, the adsorption sites of the color material component particularly in the fine particle aggregate increase, On the recording medium, such as plain paper, where the reactivity is improved, and as a result, the diffusion of the coloring material on the recording medium is suppressed to some extent, the bleeding at the color boundary is suppressed, and feathering is likely to occur. However, it is considered that a good character quality can be obtained.
[0044]
Further, the present inventors have determined that the pore properties and specific surface area of the fine particle aggregate 1411 are not only based on the fine particles 1409 contained in the liquid composition 1406, but also the liquid composition, the liquid medium composition constituting the ink, and the like. If the fine particle aggregate is configured to have a specific surface area when the fine particle aggregate is formed from the liquid composition, the fine particle in a specific pore radius region The fact that the pore volume of the agglomerates is in a specific range has a very high correlation with the image forming ability formed on the recording medium. In the present invention, the liquid composition is subjected to a predetermined treatment. It is one of the more preferable embodiments that the pore radius and pore volume of the obtained fine particle aggregate are within a specific range as described later.
[0045]
Further, according to the study by the present inventors, as described above, in the present invention, the fine particles in the liquid composition and the color material in the ink are reacted in the liquid phase on the surface of the recording medium. Therefore, the ink is an anionic or cationic water-based ink, and the liquid composition used in combination with the ink is dispersed in a state in which fine particles whose surface is charged with a polarity opposite to that of the water-based ink are dispersed. It has been found that particularly good results can be obtained when an aqueous liquid composition is contained. That is, for example, when the coloring material in the ink is anionic, if the cationic particles are used as the fine particles in the liquid composition, the coloring material is adsorbed on the surface of the fine particles in the liquid composition very efficiently. Will be. On the other hand, if it is attempted to achieve the same color material adsorption as that of the present invention by using the ink-jet coated paper which has been conventionally used, a large amount of cationic porous fine particles are required, so that the base paper is covered. It is essential to form a thick ink receiving layer. For this reason, when coated paper is used, it leads to the result of impairing the texture of the base paper. Compared with this case, in the image formation using the liquid composition of the present invention, the amount of fine particles constituting the liquid composition can be reduced. This makes it possible to form a good image with no sense of incongruity in the texture at the part.
[0046]
Further, the remaining amount of the color material itself on the surface of the recording medium is not sufficient as in the prior art (1) described above, or on the surface of the recording medium of the color material as in the prior art (2). Even if the remaining amount is sufficient, the color materials are not aggregated, and according to the present invention, the color material adsorbed on the surface of the fine particles can be left on the surface of the recording medium together with the fine particles, In addition, since these color materials maintain a monomolecular state, a high color image can be obtained.
[0047]
Further, the present invention is described in (3) in the above prior art in that an image is formed by applying a liquid composition containing fine particles and an ink having a color material to the surface of a recording medium. The method seems to be similar to the method of externally adding the fine particle-containing liquid composition to the ink. However, as described above, in the present invention, the liquid composition and the coloring material are reacted positively, and the fine particles in the liquid composition are used as a means for suppressing the aggregation (rake) of the coloring material. In the prior art described in (3) above, the purpose of applying the solution containing fine particles is to modify the surface state of the recording medium, which is completely different. That is, in the prior art, the idea of causing a chemical reaction between the fine particles in the liquid composition and the coloring material in the ink of the present invention is not disclosed. And, the difference in quality between the recorded material according to the conventional recording technology, which is presumed to be based on the difference in the mechanism, and the recorded material obtained by the present invention is obvious, and according to the present invention, An image having excellent image density and saturation and excellent image characteristics such as fixability can be obtained.
[0048]
Hereinafter, the components of the liquid composition of the present invention and the components of the ink used therewith will be described in detail.
First, the definition of the cationic ink or the anionic ink in this specification will be described. When referring to the ionic properties of the ink, it is well known in the art that the ink itself is not charged and is neutral in itself. The anionic ink or the cationic ink as used herein is a component in the ink, for example, a coloring material has an anionic group or a cationic group, and these groups are anionic group or cationic in the ink. It refers to ink that has been adjusted to behave as a base. The meaning of the anionic or cationic liquid composition is the same as described above.
[0049]
<Liquid composition>
First, the liquid composition according to the present invention will be described.
(Specific surface area of fine particle aggregate)
The liquid composition according to the present invention includes at least a solvent and fine particles having reactivity with the colorant in the ink, and fine particle aggregation formed from the liquid composition according to the following procedures (1) to (4): The specific surface area of the product determined by the BET nitrogen adsorption / desorption method is 70 to 250 m. ² Requires / g:
(1) A step of drying the liquid composition at 120 ° C. for 10 hours in an air atmosphere to substantially evaporate the solvent and drying;
(2) The temperature of the dried product is raised to 120 to 700 ° C. over 1 hour and then calcined at 700 ° C. for 3 hours;
(3) a step of leaving the fired product obtained in (2) above until it returns to room temperature, and then pulverizing the fired product; and
(4) A step of obtaining fine particle aggregates formed from the liquid composition by vacuum degassing the powder obtained in (3) above at 120 ° C. for 8 hours.
Here, the reason for performing the pretreatment consisting of the above procedures (1) to (3) is that a fine particle aggregate is formed from the liquid composition by drying, and the solvent component is completely removed by firing to remove the inside of the aggregate. This is because the pores are emptied to form voids.
[0050]
In the present invention, from the viewpoint of reactivity with the color material component, the specific surface area is 70 to 250 m when measured as described above. ² A liquid composition capable of obtaining fine particle aggregates in the range of / g is used. By using such a liquid composition, the reactivity with the color material is further increased, the occurrence of bleeding at the color boundary portion is further reduced, and the effect of further improving the character quality can be obtained. In addition, the reactivity with the color material component in the ink does not become excessively high, and it is possible to effectively suppress a decrease in color developability due to the remarkably large aggregation of the color material component. Further, it is possible to effectively suppress a decrease in dispersion stability due to excessive interaction between fine particles in the liquid composition and a decrease in storage stability of the liquid composition due to aggregation of the fine particles. A more preferable specific surface area range is 100 to 200 m. ² / G. Within this range, the balance of reactivity with the color material is particularly excellent, and the resulting image is suppressed from bleeding and further improved in character quality and suppression of streaking. Furthermore, fine particle aggregates having appropriate pores are easily formed, and the color developability is further enhanced, which is preferable from this point.
[0051]
Further, in the present invention, the specific surface area of the fine particle aggregate is determined by the BET method by the nitrogen adsorption / desorption method. The BET specific surface area is obtained by performing the pre-treatment as described above, and fine particle aggregation from the liquid composition. After forming the product, it can be determined by the method of Brunauer et al. (J. Am. Chem. Soc., Vol. 60, 309, 1938). In this invention, it measured using this method.
[0052]
(Pore radius and pore volume of fine particle aggregate)
As described above in the recording mechanism, when the liquid composition of the present invention is used for image formation, fine particle aggregates are formed in the vicinity of the surface of the recording medium by the specific fine particles contained, Inside the aggregate, pores having a certain size are formed. Then, the color material that existed alone in the ink permeates into the pores of the fine particle aggregates when the ink permeates into the recording medium, and near the entrance of the pores or the inner wall. In addition, since it is adsorbed in an ideal single molecule state, a larger amount of coloring material remains in the vicinity of the surface of the recording medium, thereby obtaining a recorded matter having a further excellent color developability. It becomes possible. Accordingly, it is preferable that the liquid composition of the present invention is further configured so that appropriate pores are formed in the fine particle aggregate during image formation.
[0053]
Here, the pores formed by the fine particles contained in the liquid composition can be measured by the nitrogen adsorption / desorption method in the same manner as in the case of measuring the specific surface area of the fine particle aggregate described above. That is, the liquid composition of the present invention has a specific surface area of a fine particle aggregate formed by the above-described method from a liquid composition containing at least fine particles and a solvent, more preferably a specific pore. By measuring the pore volume in the radius region and configuring such a value to be within a suitable range, it is possible to form a better image.
[0054]
As a result of investigations by the present inventors, in the present invention, the fine particle aggregates formed from the liquid composition by the method described above have a pore radius of 3 nm to 30 nm as measured by the nitrogen adsorption / desorption method. It was found that good image formation is possible when the pore volume in the region is in a specific range. The reason why the pore volume in the pore size region is highly correlated with the image forming ability is not clear, but it is speculated that in the region smaller than the pore radius, the color material or the inside of the fine particle aggregate It is considered that the penetration of the solvent component is remarkably reduced, the coloring material is less adsorbed due to the pores, and does not substantially contribute to the improvement of the coloring property. On the other hand, in the case of pores larger than this pore radius region, the penetration of the coloring material and solvent component is likely to occur, while the coloring material adsorbed near or inside the pore is affected by the light scattering of the pore itself. Therefore, it is considered that the coloring material is less likely to participate in light absorption, and conversely, the color developability is reduced.
[0055]
Therefore, with respect to the fine particle aggregate formed when the above pretreatment is performed on the liquid composition to be measured, the pore volume is measured in the region where the pore radius is 3 nm to 30 nm and in the region exceeding 30 nm. It is effective as a method for measuring the color development performance of a formed image formed using a liquid composition. As described above, the most suitable method for measuring the physical properties of the pores in this region is the nitrogen adsorption / desorption method. The pore radius and the pore volume were determined by the method of Barrett et al. (J. Am. Chem. Soc., J. Am. Vol. 73, 373, 1951). A more preferable measurement method is to measure the pore volume in the region having a pore radius of 3 nm to 20 nm and in the region exceeding 20 nm for the pores formed in the fine particle aggregate. In this range, particularly when the colorant is a dye, a further improvement in color developability can be obtained, which is preferable in measuring such color development performance.
[0056]
As described above, the pore radius of the fine particle aggregate is in the range of 3 nm to 30 nm from the viewpoint of preventing rapid penetration of the color material, adsorption to the vicinity of the pore entrance and the inner wall, and aggregation of the color material inside the pore. It is considered preferable. In addition, a certain amount of capacity is required at the same time in order to incorporate into the interior a color material that contributes to the improvement of color development. In addition, increasing the pore volume is thought to increase the number of pores in the fine particle aggregate, and not only the amount of coloring material adsorbed inside the pores, but also the amount of adsorption near the pore entrance increases. Conceivable.
[0057]
Therefore, from these viewpoints, the liquid composition suitably used in the present invention has pores having a pore radius in the range of 3 nm to 30 nm when the pores in the fine particle aggregate are measured by the method described above. Those having a volume of 0.4 ml / g or more and a pore volume in a region where the pore radius exceeds 30 nm are preferably 0.1 ml / g or less. By setting the pore radius within the range as described above, the coloring material and the solvent component penetrate into the pores, and the pores of the fine particle aggregate effectively contribute to the improvement of the color developability. Further, since light scattering by the pores can be suppressed, it is possible to effectively suppress the color material adsorbed on the vicinity of the pore entrance or on the inner wall from contributing to color development.
[0058]
More preferable range is a pore volume of 0.4 ml / g or more in a pore radius range of 3 nm to 20 nm and a pore volume of 0.1 ml / g or less in a region where the pore radius exceeds 20 nm. Is preferably used. The presence of many pores having a radius in the range of 3 nm to 20 nm, particularly when a dye is used as the color material, further improves the color developability and forms an image having a wider color reproduction range. it can. The pore radius and pore volume of the fine particle aggregates formed from the liquid composition change depending on not only the chemical species, shape and size of the contained fine particles, but also the solvent species and other additives and their composition ratio. It is considered that the formation state of the fine particle aggregate can be controlled by controlling these conditions. Therefore, when producing the liquid composition of the present invention, it is preferable to take these into consideration so that the shape of the pores formed in the fine particle aggregate is within the above range.
[0059]
(Action of fine particles)
Examples of the desired action of the fine particles contained in the liquid composition of the present invention that characterize the present invention include the following 1) and 2). May be achieved.
1) When mixed with ink, the color material can be adsorbed on the particle surface without impairing the color developability inherent in the color material.
2) When mixed with ink or applied to a recording medium, the dispersion stability decreases and remains on the surface of the recording medium.
[0060]
In order to satisfy the above-mentioned effect 1), as a property that the fine particles preferably have, for example, the fine particles exhibit ionicity opposite to that of the coloring material used in combination. If fine particles having such properties are used, the coloring material is electrostatically adsorbed on the surface of the fine particles. For example, when the color material used in the ink is anionic, cationic fine particles are used. Conversely, when the color material is cationic, anionic fine particles may be used. Examples of the element that adsorbs the coloring material other than the ionic material described above include the size and mass of fine particles, or the surface shape. For example, a porous fine particle having a large number of pores on the surface exhibits unique adsorption characteristics, and can favorably adsorb a coloring material by a plurality of factors such as the size and shape of the pores.
[0061]
The action 2) described above is caused by the interaction with the ink and the recording medium. For this reason, it may be achieved by each configuration. For example, the properties of the fine particles include an ionicity opposite to that of the ink composition component and the recording medium constituent component. The dispersion stability of the fine particles is also affected by the presence of an electrolyte in the ink or liquid composition. In the present invention, it is desirable that one of the above-described actions 1) and 2) be obtained instantaneously when the ink and the liquid composition are mixed. Furthermore, it is more preferable that both the effects 1) and 2) described above are obtained instantaneously when the ink and the liquid composition are mixed.
[0062]
[Cationic liquid composition]
The liquid composition of the present invention having a cationic property (hereinafter referred to as a cationic liquid composition) includes, for example, fine particles having a cationic group on the surface and an acid, and the fine particles are stably dispersed. And a liquid composition. Examples of the cationic liquid composition suitable for the present invention include those containing an acid and having a pH adjusted to 2 to 7, or those having a zeta potential of +5 to +90 mV.
[0063]
(About pH and zeta potential)
Here, the zeta potential of the liquid composition will be described. First, the basic principle of zeta potential will be described. In general, in a system in which a solid is dispersed in a liquid, if there is a free charge on the surface of the solid phase, a charged layer with an opposite charge appears in the liquid phase near the solid phase interface to maintain electrical neutrality. . This is called an electric double layer, and a potential difference caused by this electric double layer is called a zeta potential. When the zeta potential is positive, the surface of the fine particles is cationic, and when it is negative, it is anionic. Generally, the higher the absolute value, the stronger the electrostatic repulsive force acting between the fine particles, and it is said that the dispersibility is good, and at the same time, the ionicity of the fine particle surface is considered strong. That is, it can be said that the cationic fine particles have a stronger cationic property as the zeta potential is higher, and a stronger force to attract the anionic compound in the ink.
[0064]
Furthermore, as a result of examining the relationship between the zeta potential of the cationic liquid composition used for image formation and the image quality of the formed image, the present inventors have found a liquid composition having a zeta potential in the range of +5 to +90 mV. It has been found that when used, the colored portion formed on the recording medium exhibits particularly excellent color development characteristics. The reason is not clear, but probably because the fine particles are cationic enough, the anionic compound adsorbs thinly and uniformly on the surface of the fine particles without agglomeration of rapid anionic compounds (anionic colorants). Therefore, it is considered that the color material is difficult to form a huge rake, and as a result, the original color development characteristic of the color material is expressed in a better state. Further, in the cationic liquid composition according to the present invention, even after the anionic compound is adsorbed on the surface of the fine particles, the fine particles are weakly cationic and become in a dispersion unstable state, so that the fine particles are aggregated and recorded. It is thought that it is easily adsorbed on the surface of an anionic cellulose fiber or the like present in the medium and tends to remain near the surface of the recording medium.
[0065]
As a result, the following excellent effects are considered to be obtained. In other words, by using the cationic liquid composition according to the present invention, excellent color development characteristics similar to those of coated paper for ink-jet printing and white fog and color unevenness in an image area having a large amount of ink applied such as a shadow portion or a solid portion. And the color uniformity is excellent. In addition, since anionic compounds such as coloring materials are adsorbed and colored on the surface of the fine particles very efficiently compared to coated paper, the amount of cationic fine particles applied can be reduced, especially when printing on plain paper, A good image can be obtained which does not impair the texture of the paper and is excellent in scratch resistance of the printed portion. As a more preferable zeta potential range, for example, when a liquid composition containing cationic fine particles having a zeta potential in the range of +10 to +85 mV is used, the boundary between dots becomes inconspicuous when solid printing is performed, A good image with less unevenness by head scanning can be obtained.
[0066]
The pH of the cationic liquid composition according to the present invention is preferably in the range of 2 to 7 around 25 ° C. from the viewpoint of storage stability and anionic compound adsorption. Within this pH range, when mixed with an anionic ink, the stability of the anionic compound is not significantly reduced. It is possible to effectively prevent the image from becoming dull or dull. Further, when the content is within the above range, the dispersion state of the cationic fine particles is also improved, so that the storage stability of the liquid composition and the ejection stability from the recording head can be maintained well. Furthermore, when mixed with ink, the anionic substance is sufficiently adsorbed on the surface of the cationic fine particles, so that excessive penetration of the coloring material into the recording medium is suppressed, and an excellent color-forming ink jet recording product Can be obtained. A more preferable pH range is 3 to 6. In this range, corrosion of the recording head due to long-term storage can be extremely effectively prevented, and the scratch resistance of the printed portion is further improved.
[0067]
(Cationic fine particles)
Next, components constituting the cationic liquid composition according to the present invention will be described. First, as the cationic fine particles mentioned as the first component, in order to achieve the above-described effects, the surfaces of the particles themselves are cationic in a state of being dispersed in the liquid composition. It is preferable. That is, by making the surface cationic, the anionic coloring material is quickly adsorbed on the particle surface when mixed with the anionic ink, resulting in excessive penetration of the coloring material into the recording medium. Therefore, an ink jet recorded product having a sufficient image density can be obtained. On the other hand, when the surface of the fine particles is not cationic and exists separately from the water-soluble cationic compound in the liquid composition, the coloring material causes aggregation mainly in the cationic compound. In addition, since the color development characteristics of the color material itself are impaired, it is difficult to achieve color development comparable to that of ink-jet coated paper.
[0068]
The fine particles used in the cationic liquid composition need to have a cationic surface, but are naturally cationic as well as fine particles that are electrostatically anionic or neutral in nature. However, any fine particle whose surface is cationized by treatment can be suitably used as a constituent material of the liquid composition of the present invention.
[0069]
As the cationic fine particles suitably used in the present invention, if the pores are formed in the aggregates of these fine particles formed on the recording medium and the specific surface area is within a specific range, the purpose of the present invention is as follows. Can be sufficiently achieved, and there is no particular limitation on the material type of the fine particles. Specific examples include, for example, cationized silica, alumina, alumina hydrate, titania, zirconia, boria, silica boria, ceria, magnesia, silica magnesia, calcium carbonate, magnesium carbonate, zinc oxide, hydrotalcite. These composite fine particles, organic fine particles, inorganic organic composite fine particles, and the like. And in the liquid composition of this invention, it can be used individually from these or in mixture of 2 or more types.
[0070]
Among the above, fine particles made of alumina hydrate are particularly preferable because the surface of the particles has a positive charge. Further, if alumina hydrate showing a boehmite structure by X-ray diffraction method is used, excellent color development is achieved. From the viewpoints of color properties, color uniformity, storage stability, and the like. Alumina hydrate is defined by the following general formula.
[0071]
Al ₂ O _3-n (OH) _2n ・ MH ₂ O
However, in said formula, n represents one of the integers of 0-3, m has the value of 0-10, Preferably it is 0-5. mH ₂ The expression O represents a detachable aqueous phase that is often not involved in the formation of a crystal lattice, and therefore m can also take a non-integer value. However, m and n are not 0 at the same time.
[0072]
In general, a crystal of alumina hydrate having a boehmite structure is a layered compound whose (020) plane forms a giant plane, and exhibits a diffraction peak characteristic of an X-ray diffraction pattern. In addition to complete boehmite, a structure called excess boehmite containing excess water between (020) plane layers can also be used. The X-ray diffraction pattern of this pseudoboehmite shows a broader diffraction peak than complete boehmite.
[0073]
Boehmite and pseudoboehmite are not clearly distinguishable, and unless otherwise specified in the present invention, both are referred to as alumina hydrate showing a boehmite structure (hereinafter simply referred to as alumina hydrate). The (020) plane has an interplanar spacing and the (020) crystal thickness is measured by measuring the peak at a diffraction angle 2θ of 14 to 15 °. From the peak diffraction angle 2θ and the half-value width B, the plane spacing is Bragg ( In the Bragg equation, the crystal thickness can be determined using the Scherrer equation. The (020) face spacing can be used as a measure of the hydrophilicity / hydrophobicity of the alumina hydrate. The method for producing the alumina hydrate used in the present invention is not particularly limited, but any method capable of producing an alumina hydrate having a boehmite structure, for example, hydrolysis of aluminum alkoxide or hydrolysis of sodium aluminate. It can manufacture by well-known methods, such as.
[0074]
As disclosed in JP-A-56-120508, amorphous alumina hydrate by X-ray diffraction is used by changing to a boehmite structure by heat treatment at 50 ° C. or higher in the presence of water. be able to. A method that can be particularly preferably used is a method of obtaining an alumina hydrate by adding an acid to a long-chain aluminum alkoxide, followed by hydrolysis and peptization. Here, the long-chain aluminum alkoxide is, for example, an alkoxide having 5 or more carbon atoms, and when an alkoxide having 12 to 22 carbon atoms is used, removal of alcohol and hydration of alumina in the production process as described later. This is preferable because shape control of the object becomes easy.
[0075]
In the above, as the acid added to the long-chain aluminum alkoxide, one or two or more kinds of organic acids and inorganic acids can be freely selected and used. Nitric acid is most preferably used in terms of shape control and dispersibility of the obtained alumina hydrate. It is also possible to control the particle size by performing hydrothermal synthesis or the like after this step. When hydrothermal synthesis is performed using a dispersion of alumina hydrate containing nitric acid, the nitric acid in the aqueous solution is taken into the surface of the alumina hydrate as nitrate radicals, which improves the water dispersibility of the hydrate. it can.
[0076]
The above-described method of hydrated alumina by hydrolysis of a long-chain aluminum alkoxide has an advantage that impurities such as various ions are less likely to be mixed as compared with a method of producing alumina hydrogel or cationic alumina. Furthermore, long-chain aluminum alkoxides should be fully alcohol-dealcoholated compared to the case where the long-chain alcohol after hydrolysis is a short-chain alkoxide such as, for example, aluminum isoproxide. There is also an advantage of being able to. In the above method, it is preferable to set the pH of the solution at the start of hydrolysis to less than 6. If the pH exceeds 8, the finally obtained alumina hydrate becomes crystalline, which is not preferable.
[0077]
Moreover, as the alumina hydrate used in the present invention, an alumina hydrate containing a metal oxide such as titanium dioxide can be used as long as it shows a boehmite structure by an X-ray diffraction method. The content ratio of the metal oxide such as titanium dioxide is preferably 0.01 to 1.00% by mass of the alumina hydrate because the optical density becomes high, more preferably 0.13 to 1.00% by mass. If such a material is used, the adsorption speed of the coloring material is increased, and bleeding and beading are less likely to occur. Furthermore, the titanium dioxide used in this case needs to have a titanium valence of +4. The content of titanium dioxide can be examined by the ICP method after melting in boric acid. Further, the distribution of titanium dioxide in the alumina hydrate and the valence of titanium can be analyzed using ESCA.
[0078]
For example, the surface of the alumina hydrate can be etched with argon ions for 100 seconds and 500 seconds to examine changes in the titanium content. When titanium valence is less than +4, titanium dioxide will act as a catalyst, and the weather resistance of the resulting printed matter may decrease, or yellowing of the printed part may occur easily. is there.
[0079]
The titanium dioxide may be contained only in the vicinity of the surface of the alumina hydrate or may be contained up to the inside. Moreover, content may change from the surface to the inside. It is more preferable that titanium dioxide is contained only in the very vicinity of the surface because the electrical properties of the alumina hydrate are easily maintained.
[0080]
As a method for producing an alumina hydrate containing titanium dioxide, for example, aluminum alkoxide and titanium as described in “Science of Surface”, page 327 (edited by Kenji Tamaru, 1985) published by Academic Publishing Center. A method in which a mixed solution of alkoxide is hydrolyzed and produced is preferred. As another method, when the mixed liquid of the aluminum alkoxide and the titanium alkoxide is hydrolyzed, it can be produced by adding alumina hydrate as a nucleus of crystal growth.
[0081]
Instead of titanium dioxide, silica, magnesium, calcium, strontium, barium, zinc, boron, germanium, tin, lead, zirconium, indium, phosphorus, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, What contains either oxides, such as nickel and ruthenium, can also be used. For example, alumina hydrate containing silica is effective in improving the scratch resistance of the printed part.
[0082]
As the alumina hydrate suitably used for the production of the liquid composition of the present invention, those having a (020) plane spacing in the range of 0.614 nm to 0.626 nm are preferably used. Within this range, a dispersion composition having good dispersion stability of alumina hydrate particles in the liquid composition and excellent storage stability and ejection stability can be obtained. The reason for this is not clear, but when the (020) plane spacing is within the above range, the ratio of the amount of hydrophobicity and hydrophilicity of the alumina hydrate is in an appropriate range. It is presumed that the discharge stability of the liquid composition is improved by the dispersion stability due to appropriate repulsion between particles and the balance of wettability inside the discharge port.
[0083]
The alumina hydrate used in the present invention preferably has a crystal thickness in the range of (020) plane of 4.0 to 10.0 nm. It is because it is excellent in transparency and the adsorptivity of a coloring material within this range. According to the knowledge of the present inventors, there is a correlation between the plane spacing of the (020) plane and the crystal thickness of the (020) plane, so if the plane spacing of the (020) plane is within the above range, (020) The crystal thickness of the surface can be adjusted to a range of 4.0 to 10.0 nm.
[0084]
Furthermore, alumina (aluminum oxide) produced by heat-treating the above-mentioned alumina hydrate, metal aluminum, aluminum salt or the like by calcination or the like is also preferably used since it has a positive charge. Alumina includes α-type, γ-type, and δ-, χ-, η-, ρ-, and β-type crystalline states, and the surface is kept cationic and stably dispersed in water. Any can be used. Among them, the γ type has an active surface, a high adsorbing power for coloring materials, and can easily form a relatively finely divided stable fine particle dispersion. Therefore, it is excellent in color development, storage stability, ejection stability, etc. Can be used.
[0085]
In addition, the above-mentioned cationic fine particles used in the present invention have an average particle diameter measured by a dynamic light scattering method of 0. 0 from the viewpoint of color developability after printing, color uniformity and storage stability. The thing of the range of 005-1 micrometer is used suitably. Within this range, excessive penetration into the recording medium can be effectively prevented, and deterioration in color development and color uniformity can be suppressed. In addition, it is possible to prevent the cationic fine particles from settling in the liquid composition, and it is possible to effectively prevent a decrease in storage stability of the liquid composition. More preferably, the average particle diameter is in the range of 0.01 to 0.8 μm. When such fine particles are used, the scratch resistance and texture of the image after printing on the recording medium are particularly preferable. It becomes. More preferably, the average particle diameter is in the range of 0.03 to 0.3 μm, and such fine particles have fine pore agglomerates formed on the recording medium having a desired pore radius. This is preferable because it can be easily formed effectively in the region.
[0086]
(Pore physical properties and shape of cationic fine particles)
In addition, the above-described cationic fine particles used in the present invention efficiently form pores of fine particle aggregates formed on the recording medium, and at the same time, efficiently adsorb the coloring material on the surface of the fine particles themselves. In addition, it is preferable that the fine pores in the nitrogen adsorption / desorption method have a maximum pore radius of 2 nm to 12 nm and a total pore volume of 0.3 ml / g or more. More preferably, the fine pores of the fine particle aggregate formed on the recording medium have a maximum pore radius of 3 nm to 10 nm and a total pore volume of 0.3 ml / g or more. This is preferable because it is easily formed effectively in the pore radius region.
[0087]
In the present invention, the cationic fine particles as mentioned above have a BET specific surface area of 70 to 300 m. ² / G within the range, the adsorbing point of the coloring material on the surface of the fine particles is sufficiently present, so that the coloring material can be more effectively left in the vicinity of the surface of the recording medium in a monomolecular state, and the coloring property is improved. Since it can contribute to improvement, it is preferable. Further, from the viewpoint of reactivity with the color material component, the BET specific surface area of the fine particles is 100 to 250 m. ² / G of fine particles, it is easy to effectively control the specific surface area of the fine particle aggregates within the target range of the present invention, so that the fine particles are excellent in suppressing bleeding at the color boundary and improving the character quality. A liquid composition that easily forms an aggregate is easily obtained. Furthermore, the specific surface area is 130-200m ² When fine particles within the range of / g are used, the balance of the reactivity with the colorant is particularly excellent, and the book capable of forming an image excellent in suppressing bleeding and improving character quality and further suppressing unevenness. It can be a liquid composition of the invention. Furthermore, it is preferable to use fine particles having such characteristics because fine particle aggregates having appropriate pores are easily formed, and the color developability of an image obtained when used for image formation can be further enhanced.
[0088]
The shape of the fine particles used in the present invention can be determined by dispersing fine particles in ion-exchanged water and dropping them on the collodion film to prepare a measurement sample and observing it with a transmission electron microscope. In the present invention, when fine particle aggregates are formed on a recording medium, fine particles are formed into needles, flat plates, or spherical primary particles in a direction in which pores are formed in the aggregates. A non-spherical shape such as a rod shape or a necklace shape forming secondary particles connected with each other can be suitably used.
[0089]
According to the study by the present inventors, the flat plate shape has better dispersibility in water than the needle shape or the hair bundle (ciliform shape), and the fine particle orientation is improved when the fine particle aggregate is formed. Since it becomes random, the pore volume becomes larger, which is more preferable. Here, the hair-like bundle shape means a state in which needle-shaped fine particles are gathered like a bundle of hairs in contact with each other. In particular, among the alumina hydrates that can be preferably used in the present invention, pseudoboehmite is described in the above-mentioned document (Rocek J., etal, Applied Catalysis, 74, 29-36, 1991). It is generally known that there are cilia and other shapes.
[0090]
The aspect ratio of tabular grains can be determined by the method defined in Japanese Patent Publication No. 5-16015. Aspect ratio is expressed as the ratio of diameter to particle thickness. Here, the diameter indicates the diameter of a circle having an area equal to the projected area of particles when the alumina hydrate is observed with a microscope or an electron microscope. The aspect ratio is observed in the same manner as the aspect ratio, and is represented by the ratio of the diameter indicating the minimum value and the diameter indicating the maximum value of the flat plate surface. Further, in the case of a hair bundle shape, the method for obtaining the aspect ratio is to determine the diameter and length of the upper and lower circles, using individual acicular alumina hydrate particles forming the hair bundle as a cylinder, It can be obtained by taking the ratio. The most preferred shape of the alumina hydrate is preferably in the range of an average aspect ratio of 3 to 10 for a flat plate, and in the range of 3 to 10 for a hair bundle. If the average aspect ratio is within the above range, a gap can easily be formed between the particles when the fine particle aggregate is formed, so that a porous structure can be easily formed.
[0091]
The content of the cationic fine particles as described above in the cationic liquid composition according to the present invention may be determined as appropriate depending on the type of the substance used, but is 0.1 to 40 on a mass basis. % Is a preferable range for achieving the object of the present invention, more preferably 1 to 30%, and further preferably 3 to 15%. Within such a range, an excellent color image can be stably obtained regardless of the paper type, and the storage stability and ejection stability of the liquid composition are particularly excellent.
[0092]
(acid)
As described above, the cationic liquid composition according to the present invention preferably contains an acid and has a pH adjusted to 2 to 7, but the second component acid is a cation. By ionizing the surface of the conductive fine particles and increasing the surface potential, the dispersion stability of the fine particles in the liquid is improved, the adsorptivity of the anionic compound (anionic colorant) in the ink is improved, and the liquid composition Plays a role in adjusting viscosity. The acid suitably used in the present invention is not particularly limited as long as the desired pH, zeta potential, or fine particle dispersibility can be obtained in combination with the cationic fine particles to be used. It can be freely selected from inorganic acids and organic acids.
[0093]
Specifically, examples of the inorganic acid include hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, boric acid, and carbonic acid, and examples of the organic acid include carboxylic acid and sulfone described below. Examples include acids and amino acids.
[0094]
Examples of the carboxylic acid include formic acid, acetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, fluoroacetic acid, trimethylacetic acid, methoxyacetic acid, mercaptoacetic acid, glycolic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, and caprine. Acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, o- Chlorobenzoic acid, m-chlorobenzoic acid, p-chlorobenzoic acid, o-bromobenzoic acid, m-bromobenzoic acid, p-bromobenzoic acid, o-nitrobenzoic acid, m-nitrobenzoic acid, p-nitrobenzoic acid Acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, tartaric acid, maleic acid, fumaric acid Acid, citric acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, p-hydroxybenzoic acid, anthranilic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-methoxybenzoic acid, m-methoxybenzoic acid, and Examples include p-methoxybenzoic acid.
[0095]
Examples of the sulfonic acid include benzenesulfonic acid, methylbenzenesulfonic acid, ethylbenzenesulfonic acid, dodecylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid, and 5-sulfone. Examples include salicylic acid, 1-sulfonaphthalene, 2-sulfonaphthalene, hexanesulfonic acid, octanesulfonic acid, and dodecanesulfonic acid.
[0096]
Examples of amino acids include glycine, alanine, valine, α-aminobutyric acid, γ-aminobutyric acid, β-alanine, taurine, serine, ε-amino-n-caproic acid, leucine, norleucine, and phenylalanine.
[0097]
And in the cationic liquid composition concerning this invention, these can be used 1 type or in mixture of 2 or more types. Among these, those having a primary dissociation constant pka of 5 or less in water of the acid to be used are particularly suitable because they are particularly excellent in dispersion stability of cationic fine particles and adsorbability of anionic compounds. Specific examples include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, acetic acid, formic acid, oxalic acid, lactic acid, citric acid, maleic acid, and malonic acid.
[0098]
In the cationic liquid composition according to the present invention, the mixing ratio of the cationic fine particles (A) and the acid (B) in the liquid composition is A: B = 200: 1 to 5: 1, more preferably on a mass basis. A range of 150: 1 to 8: 1 is preferable in terms of improving the dispersion stability of the cationic fine particles and improving the adsorptivity of the anionic compound to the fine particle surfaces.
[0099]
(Other components)
Next, the other component which comprises the cationic liquid composition concerning this invention is demonstrated concretely. The cationic liquid composition according to the present invention contains the above-described cationic fine particles as essential components, preferably contains an acid as described above, and usually contains water as a liquid medium. It may contain a water-soluble organic solvent and other additives.
[0100]
Examples of the water-soluble organic solvent used in this case include amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, Alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol, ethylene glycol methyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl Lower alkyl ethers of polyhydric alcohols such as ether, ethanol, isopropyl alcohol, n-butyl alcohol Lumpur, other monohydric alcohols such as isobutyl alcohol, glycerin, N- methyl-2-pyrrolidone, 1,3-dimethyl - imidazolidinone, triethanolamine, sulfolane, dimethyl monkey Hoki side, and the like. Examples of the humectant include nitrogen-containing compounds such as urea, thiourea, ethylene urea, alkyl urea, alkyl thiourea, dialkyl urea, and dialkyl thiourea, and saccharides such as glucitol, mannitol, and inositol. Although there is no restriction | limiting in particular about content of the said water-soluble organic solvent and a moisturizing agent, For example, 5 to 60% of the liquid composition total mass, Furthermore, 5 to 40% is a suitable range.
[0101]
In addition to the above, the liquid composition of the present invention may further include a viscosity adjusting agent, a pH adjusting agent, a preservative, various surfactants, an antioxidant, an evaporation accelerator, a water-soluble cationic compound, You may mix | blend additives, such as binder resin, suitably. The selection of the surfactant is particularly important in adjusting the permeability of the liquid composition to the recording medium.
[0102]
Surfactants include primary, secondary and tertiary amine salt type compounds, specifically, quaternary ammonium salt type compounds such as laurylamine, coconutamine, stearylamine, rosinamine and other hydrochlorides and acetates. Compounds, specifically lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, etc .; pyridinium salt type compounds, specifically cetylpyridinium chloride, cetylpyridinium bromide, etc .; imidazoline type cations Compounds, specifically 2-heptadecenyl-hydroxyethylimidazoline, etc .; ethylene oxide adducts of higher alkylamines, specifically, cationic surfactants such as dihydroxyethyl stearylamine, and a certain pH range Oite cationic amphoteric surfactants such as showing a can also be used. Specifically, for example, amino acid type amphoteric surfactant; R-NH-CH ₂ -CH ₂ -COOH type compounds; betaine type compounds, specifically, carboxylate type amphoteric surfactants such as stearyl dimethyl betaine and lauryl dihydroxyethyl betaine, as well as sulfate ester type, sulfonic acid type, phosphate ester type, etc. And amphoteric surfactants. Examples of the nonionic surfactant include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, acetylene alcohols, and acetylene glycols. From these, one or more kinds can be appropriately selected and used.
[0103]
Among the above, acetylene alcohols and acetylene glycols are particularly preferably used. That is, these surfactants can improve the permeability of the liquid composition to plain paper, while suppressing the foaming of the liquid composition, and even if the foam is a foam, Can be extinguished. In addition, although the usage-amount changes with surfactant to be used, it is desirable to set it as 0.05-5 mass% with respect to the liquid composition whole quantity, since sufficient permeability of a liquid composition can be ensured.
[0104]
In addition, the water-soluble cationic compound can be freely selected and added within a range that does not inhibit the action and effect of the present invention for the purpose of further imparting the cationic property of the cationic liquid composition according to the present invention. it can.
[0105]
The binder resin can be used in combination as long as it does not impair the texture of the recording medium and the storage stability and ejection stability of the liquid composition for the purpose of improving the scratch resistance of the image. Specifically, for example, water-soluble polymers such as polyvinyl alcohol, gelatin, polyvinyl pyrrolidone, polyethylene oxide, casein, starch, carboxymethyl cellulose, polyacrylic acid, polyurethane, polyvinyl acetate, etc., and emulsions of copolymers thereof, A latex such as SBR and NBR can be freely selected and used.
[0106]
(Surface tension of liquid composition)
The cationic liquid composition according to the present invention is more preferably colorless or white, but the color may be adjusted according to the color of the recording medium. Furthermore, as a suitable range of various physical properties of the liquid composition containing the above components, the surface tension is 10 to 60 mN / m (dyn / cm), more preferably 10 to 40 mN / m (dyn / cm). The viscosity is 1 to 30 mPa · s (cP).
[0125]
[Method of dispersing liquid composition]
Cations such as those listed above Sex As a method for dispersing the fine particles in the production of the liquid composition according to the present invention containing fine particles, it can be appropriately selected from methods generally used for dispersion. As an apparatus to be used, gentle stirring such as a homomixer or a rotating blade is preferable to a grinding type disperser such as a ball mill or a sand mill. The shear stress varies depending on the viscosity of the liquid composition, the amount or volume of the contained fine particles, but is, for example, 0.1 to 100.0 N / m. ² It is preferable to set it as the range. Furthermore, 0.1 to 20.0 N / m ² Within this range, it is possible to effectively prevent the pore volume of the fine particles themselves from being destroyed and the pore volume from becoming smaller, which is more preferable.
[0126]
The dispersion time varies depending on the amount of the dispersion, the size of the container, the temperature of the dispersion, and the like, but is preferably 30 hours or less from the viewpoint of preventing the change in the crystal structure of the fine particles, and further 10 hours. The pore structure of the fine particles can be controlled within the above range as long as it is below. During the dispersion treatment, the temperature of the dispersion liquid may be kept within a certain range by cooling or keeping warm. The preferred temperature range is 10 to 100 ° C., although it varies depending on the dispersion treatment method, material or viscosity.
[0127]
<Water-based ink>
[Anionic ink]
Next, an aqueous anionic ink (hereinafter referred to as an anionic ink) used when the ink set of the present invention is configured in combination with the cationic liquid composition according to the present invention described above will be described. The ink set here refers to, for example, a combination of the above-described cationic liquid composition and at least one kind of anionic ink containing an anionic substance (anionic color material). Further, a combination of at least two inks obtained by removing the liquid composition of the present invention from this ink set is called an ink subset. The anionic ink used in the present invention uses a water-soluble dye containing an anionic group as a color material, or a combination of an anionic compound when a pigment is used as a color material. In the invention, it is preferable to use an anionic colorant). The anionic ink as used in the present invention further includes water, a water-soluble organic solvent and other components such as a viscosity adjuster, a pH adjuster, a preservative, a surfactant, and an antioxidant. An agent or the like is included as necessary. Hereinafter, each component of these inks will be described.
[0128]
(Water-soluble dye)
The water-soluble dye having an anionic group used in the present invention is not particularly limited as long as it is a water-soluble acidic dye, a direct dye, or a reactive dye described in the Color Index. Further, even those not described in the color index are not particularly limited as long as they have an anionic group such as a sulfone group or a carboxyl group. Among the water-soluble dyes herein, those having a pH dependency of solubility are included.
[0129]
(Pigment)
As another form of the water-based anionic ink, a pigment and an anionic compound are used instead of the water-soluble dye having an anionic group as described above, and water, a water-soluble organic solvent and other components such as a viscosity are used. The ink may contain an adjusting agent, a pH adjusting agent, a preservative, a surfactant, an antioxidant, and the like as necessary. Here, the anionic compound may be a pigment dispersant, or when the pigment dispersant is not anionic, an anionic compound different from the dispersant may be added. Of course, even when the dispersant is an anionic compound, it may further be added with another anionic compound.
[0130]
Although there is no limitation in particular in the pigment which can be used by this invention, For example, the pigment demonstrated below can be used conveniently. First, the carbon black used in the black pigment ink is carbon black produced by the furnace method or the channel method, the primary particle size is 15-40 mμ (nm), and the specific surface area by the BET method is 50-300 m. ² / G, DBP oil absorption is preferably 40 to 150 ml / 100 g, volatile content is 0.5 to 10% by mass, and pH value is 2 to 9.
[0131]
As such a thing, for example, no. 2300, no. 900, MCF88, No. 40, no. 52, MA7, MA8, no. 2200B (Mitsubishi Kasei), RAVEN 1255 (Colombia), REGAL 400R, REGAL 660R, MOGUL L (Made by Botbot), Color Black FW1, Color Black FW18, Color Black S170, Color Black S150, Printex 35, Printex Commercial products such as U (above, manufactured by Degussa) can be used. Also, a new prototype for the present invention may be used.
[0132]
Examples of pigments used in yellow ink include CIPigment Yellow 1, CIPigment Yellow 2, CIPigment Yellow 3, CIPigment Yellow 13, CIPigment Yellow 16, CIPigment Yellow 74, CIPigment Yellow 83, CIPigment Yellow 93, CIPigment Yellow 128, and CIPigment Yellow 134, CIPigment Yellow 144, and the like.
[0133]
Examples of pigments used as magenta ink include CIPigment Red 5, CIPigment Red 7, CIPigment Red 12, CIPigment Red 48 (Ca), CIPigment Red 48 (Mn), CIPigment Red 57 (Ca), CIPigment Red 112, and CIPigment Red 122, CIPigment Violet 19, etc. are mentioned.
[0134]
Examples of the pigment used as the cyan ink include CIPigment Blue 1, CIPigment Blue 2, CIPigment Blue 3, CIPigment Blue 15: 3, CIPigment Blue 16, CIPigment Blue 22, CIVat Blue 4, CIVat Blue 6, and the like.
In addition, any of the above-described color materials that are newly produced for the present invention can be used.
[0135]
(Pigment dispersant)
As the pigment dispersant that can be used in the ink used in the present invention, any water-soluble resin having a function of stably dispersing the pigment in water or an aqueous medium due to the presence of an anionic group can be used. But it can be used. In particular, those having a weight average molecular weight in the range of 1,000 to 30,000 are preferred. More preferred are those in the range of 3,000 to 15,000. Specifically, for example, styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, hydrophobic monomers such as aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acid, or acrylic acid, acrylic acid derivatives, A block copolymer, a graft copolymer or a random copolymer composed of two or more monomers selected from maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid and fumaric acid derivatives, or these Examples include salts. These resins are alkali-soluble resins that are soluble in an aqueous solution in which a base is dissolved.
[0136]
Further, it may be a homopolymer composed of a hydrophilic monomer or a salt thereof. In addition, water-soluble resins such as polyvinyl alcohol, carboxymethyl cellulose, and naphthalene sulfonic acid formaldehyde condensate can also be used. However, the use of an alkali-soluble resin has the advantages that the viscosity of the dispersion can be reduced and the dispersion is easy. The water-soluble resin is preferably used in the range of 0.1 to 5% by mass with respect to the total amount of ink.
[0137]
The pigment ink that can be used in the present invention is constituted by dispersing or dissolving the above pigment and water-soluble resin in a water-soluble medium. In the pigment-based ink that can be used in the present invention, a suitable aqueous medium is a mixed solvent of water and a water-soluble organic solvent. The water is not general water containing various ions but ion-exchanged water (deionized water). ) Is preferred.
[0138]
When the dispersant is not an anionic polymer, it is preferable to add an anionic compound to the ink containing the pigment described above. Examples of the anionic compound preferably used in the present invention include a high molecular weight substance such as an alkali-soluble resin described in the section of the pigment dispersant and a low molecular weight anionic surfactant as described below. it can.
[0139]
Specific examples of the low molecular weight anionic surfactant include, for example, disodium lauryl sulfosuccinate, disodium polyoxyethylene lauroyl ethanolamide ester sulfosuccinate, disodium polyoxyethylene alkylsulfosuccinate, carboxylated polyoxyethylene Lauryl ether sodium salt, carboxylated polyoxyethylene tridecyl ether sodium salt, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether sulfate triethanolamine, polyoxyethylene alkyl ether sodium sulfate, sodium alkyl sulfate, alkyl sulfate triethanol Although amine etc. are mentioned, it is not necessarily limited to these. A suitable use amount of the anionic substance as described above is in a range of 0.05 to 10% by mass, and more preferably 0.05 to 5% by mass with respect to the total amount of the ink.
[0140]
(Self-dispersing pigment)
In addition, as a pigment that can be used for an anionic ink, a self-dispersing pigment that can be dispersed in water or an aqueous medium can be used without using a dispersant. The self-dispersing pigment is one in which at least one anionic hydrophilic group is bonded to the pigment surface directly or through another atomic group. The anionic hydrophilic group is, for example, at least one selected from the hydrophilic groups listed below, and the other atomic group is an alkylene group having 1 to 12 carbon atoms or a substituent. Examples thereof include a phenylene group which may have or a naphthylene group which may have a substituent.
-COOM, -SO _Three M, -SO ₂ NH ₂ , -PO _Three HM, -PO _Three M ₂ (M in these formulas represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium.)
[0141]
As described above, since the pigment charged anionic by introduction of a hydrophilic group on the pigment surface has excellent water dispersibility due to repulsion of ions, a dispersant or the like can be added even when contained in an aqueous ink. Even if it is not added, a stable dispersion state is maintained. It is particularly preferable when the pigment is carbon black.
[0142]
(Additional component in ink)
In addition to the above components, a surfactant, an antifoaming agent, an antiseptic, or the like can be added to the ink as necessary in order to obtain an ink having a desired physical property value. A water-soluble dye or the like can also be added.
[0143]
Examples of the surfactant include anionic surfactants such as fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, alkylallylsulfonates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters , Nonionic surfactants such as polyoxyethylene sorbitan alkyl esters, acetylene alcohols, acetylene glycols, and the like. In the present invention, one or more of these may be appropriately selected and used. it can. Of these, acetylene alcohols and acetylene glycols are particularly preferably used.
[0144]
That is, these surfactants can improve the penetrability of the ink into plain paper, but do not easily cause the ink to foam, and can also quickly eliminate the foam when foamed. The optimum amount of the surfactant in the ink varies depending on the type of the surfactant. However, if the range is 0.05 to 5% by mass based on the total mass of the ink, the ink has sufficient permeability. Therefore, it is preferable to adjust appropriately within this range. That is, by adding such an amount of surfactant to the ink, the ink permeability to plain paper can be improved, while suppressing the bubbling of the ink, and if it was a bubble Can quickly eliminate the bubbles.
[0145]
When preparing the ink used in the present invention, the surface tension at 25 ° C. is preferably 10 mN / m (dyne / cm) or more. More preferably, the surface tension is adjusted to 20 mN / m or more, more preferably 30 mN / m or more, and further the surface tension is adjusted to 70 mN / m or less. For this purpose, it is preferable to determine the addition amount of the surfactant so that the surface tension of the ink falls within such a range. In this way, when the ink used in the present invention is applied to the ink jet recording method, it is possible to effectively suppress the occurrence of printing misalignment (deviation of the landing point of ink droplets) due to wetting of the nozzle tip.
[0146]
As a method for producing a pigment-based ink as described above, first, a pigment is added to an aqueous solution containing at least a pigment-dispersing resin and water, and the mixture is stirred and then subjected to a dispersion treatment using a dispersion means described later. Then, a desired dispersion is obtained by centrifuging as necessary. Next, the above-described components may be further added to the dispersion and stirred to obtain ink.
[0147]
Further, when an alkali-soluble resin is used as a dispersant, it is necessary to add a base in order to dissolve the resin. At this time, the amount of amine or base for dissolving the resin needs to be added at least 1 times the amount of amine or base determined by calculation from the acid value of the resin. The amount of amine or base can be calculated by the following formula.

[0148]
Further, when the premixing is performed for 30 minutes or more before the aqueous solution containing the pigment is dispersed, the pigment dispersion efficiency is improved. This premixing operation improves the wettability of the pigment surface and promotes the adsorption of the dispersant to the pigment surface.
[0149]
Examples of bases added to the dispersion when an alkali-soluble resin is used include, for example, organic amines such as monoethanolamine, diethanolamine, triethanolamine, aminemethylpropanol, and ammonia, or potassium hydroxide and sodium hydroxide. It is preferable to use an inorganic base such as
[0150]
On the other hand, the disperser used for preparing the pigment ink may be any disperser that is generally used, and examples thereof include a ball mill and a sand mill. Among these, a high speed type sand mill is preferable, and examples thereof include a super mill, a sand grinder, a bead mill, an agitator mill, a glen mill, a dinol mill, a pearl mill, and a cobol mill (all are trade names).
[0151]
In addition to the above-described components, the ink used in the present invention may contain a water-soluble organic solvent, a surfactant, a pH adjuster, a rust inhibitor, an antifungal agent, an antioxidant, an evaporation accelerator, a chelate as necessary. You may add additives, such as an agent and a water-soluble polymer.
[0152]
The liquid medium for dissolving or dispersing the colorant used in the present invention is preferably a mixture of water and a water-soluble organic solvent. Specific examples of the water-soluble organic solvent include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol and the like. Amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol and triethylene glycol , 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol and other alkylene groups containing 2 to 6 carbon atoms Lower alkyl ethers of polyhydric alcohols such as lenglycols, glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazo Examples thereof include cyclic amide compounds such as lysinone, sulfolane, dimethyl sulfoxide, 2-pyrrolidone and ε-caprolactam, and imide compounds such as succinimide.
[0153]
In general, the content of the water-soluble organic solvent as described above is preferably 1 to 40% by mass%, more preferably 3 to 30% with respect to the total mass of the ink. In addition, when the water content in the ink is in the range of 30 to 95% by mass, the colorant has good solubility, the ink viscosity can be prevented from increasing, and the ink can be fixed. The characteristics can be sufficiently satisfied.
[0154]
The anionic ink used in the present invention can also be used as a general water-based writing instrument, but is particularly suitable for application to an ink jet recording method in which ink is ejected by the foaming phenomenon of ink due to thermal energy. It is extremely stable and does not generate satellite dots. However, in this case, thermal physical property values (for example, specific heat, thermal expansion coefficient, thermal conductivity, etc.) may be adjusted.
[0171]
<Concentration of water-based ink>
Anion as described above Sex The mass concentration of the color material component contained in the ink is appropriately selected according to the type of the color material such as an aqueous dye, pigment, or self-dispersing pigment, but is 0.1 to 20% by mass with respect to the mass of the ink. In particular, the range of 0.1 to 12% by mass is preferable. Further, when the mass concentration of the color material component is in the range of 0.3 to 7% by mass, the relationship between the concentration of the fine particles in the liquid composition and the concentration of the color material in the ink is relative to the fine particles 1 on a mass basis. When the color material is 1.2 or less, particularly 1.0 or less, the color developability of an image formed under ordinary two-component recording conditions is particularly excellent.
[0172]
<Method for forming a colored portion on a recording medium>
Next, a method for forming a colored portion on the recording medium of the present invention using the liquid composition according to the present invention described above will be described. The method for forming a colored portion on the recording medium of the present invention includes the step (i) of applying an ink containing a coloring material as described above to the recording medium, and the liquid composition according to the present invention to the recording medium. And (ii). In the present invention, in step (i), the anion as described above Sex It is preferable to use the above-described liquid composition in which water-based ink is used and in step (ii), fine particles having a surface charged with a polarity opposite to that of the ink are contained in a dispersed state. It is preferable that the water-based ink and the liquid composition are applied so as to come into contact with each other in a liquid state on the surface of the recording medium.
Hereinafter, a method for applying the liquid composition and the aqueous ink having the above-described configuration onto a recording medium will be described.
[0173]
The method for forming a colored portion on a recording medium according to the present invention includes the step (ii) of applying a liquid composition onto the recording medium and the step (i) of applying ink to the recording medium. At this time, it is preferable to apply the liquid composition to the colored portion forming region of the recording medium or the colored portion forming region and the vicinity thereof so that the water-based ink and the liquid composition are in contact with each other in a liquid state. The colored portion forming region here is a region to which ink dots adhere, and the vicinity of the colored portion forming region is a region separated by about 1 to 5 dots outside the region to which ink dots adhere. Refers to that.
[0174]
In the method for forming a colored portion on the recording medium of the present invention, any of the above-described liquid composition and water-based ink can be applied by any method as long as they come into contact with each other in a liquid state on the recording medium. You may let them. Therefore, it does not matter which liquid composition or ink is applied on the recording medium first. For example, step (i) may be performed after performing step (ii), or step (ii) may be performed after performing step (i). In addition, it is also a preferred embodiment that step (ii) is performed after step (i) is performed, and then step (i) is performed again. In addition, when the liquid composition is first applied to the recording medium, the time from when the liquid composition is applied to the recording medium to when the ink is applied onto the recording medium is particularly limited. However, in order to contact each other in a liquid state, it is preferable to apply ink onto the recording medium almost simultaneously or within several seconds.
[0175]
(Recording medium)
The recording medium used in the above-described method for forming a colored portion on the recording medium of the present invention is not particularly limited, and so-called ordinary paper such as copy paper and bond paper, which has been conventionally used. Paper can be suitably used. Of course, a coated paper specially prepared for inkjet recording and a transparent film for OHP can also be suitably used. Furthermore, it can be suitably used for general high-quality paper and glossy paper.
[0176]
(Method for applying liquid composition)
As a method for applying the liquid composition according to the present invention on the recording medium, for example, a method of applying the liquid composition to the entire surface of the recording medium by spraying, rollers, or the like is also conceivable. However, more preferably, by the ink jet system that can selectively and uniformly apply the liquid composition only to the colored portion forming region to which the ink is applied, or to the vicinity of the colored portion forming region and the colored portion forming region. Good to do. In this case, various ink jet recording methods can be used, but a method of discharging droplets using bubbles generated by thermal energy is particularly preferable.
[0177]
<Inkjet recording apparatus>
Hereinafter, specific examples of the ink jet recording apparatus of the present invention will be described.
One form of the ink jet recording apparatus of the present invention includes an ink containing portion containing ink containing a color material, a first recording unit including an ink jet head that discharges the ink, and, for example, a polarity opposite to that of water-based ink A second recording unit comprising: a liquid composition containing portion containing the liquid composition according to the present invention, in which fine particles whose surface is charged are contained in a dispersed state; and an ink jet head for discharging the liquid composition It is characterized by having.
[0178]
FIG. 1 is a schematic perspective view showing an example of a schematic configuration of an ink jet printer that records output information, which is an ink jet recording apparatus according to the present invention having the above-described embodiment. In FIG. 1, reference numeral 1 denotes a cartridge (hereinafter referred to as a print head cartridge) constituting an ink jet head for forming a colored portion by discharging ink and printing, and 2 for discharging a liquid composition. The liquid composition discharge head is a cartridge (hereinafter, liquid composition head cartridge). In the illustrated example, four print head cartridges 1 using different color inks and one liquid composition head cartridge 2 are used. Each head cartridge 1 for printing has a structure in which an ink tank portion is provided in the upper portion and an ink discharge portion (print portion) is provided in the lower portion. The head cartridge 2 for liquid composition has a structure in which a liquid composition tank section is provided at the top and a liquid composition discharge section is provided at the bottom. Further, these head cartridges 1 and 2 are provided with connectors for receiving drive signals and the like. 3 is a carriage.
[0179]
On the carriage 3, four print head cartridges 1 for printing with different color inks and one liquid composition head cartridge 2 are positioned and mounted. Further, the carriage 3 is provided with a connector holder for transmitting signals for driving the print head cartridges 1 and the liquid composition head cartridge 2, and the heads are connected via the connector holders. The cartridges 1 and 2 are electrically connected.
[0180]
Each print head cartridge 1 contains ink of different colors, for example, yellow (Y), magenta (M), cyan (C), and black (B). In this figure, from the left in the drawing, print head cartridges 1Y, 1M, 1C, and 1B for yellow, magenta, cyan, and black inks are mounted, and a liquid composition that contains the liquid composition at the right end. A product head cartridge 2 is mounted.
[0181]
In FIG. 1, reference numeral 4 denotes a scanning rail that extends in the main scanning direction of the carriage 3 and slidably supports the carriage 5, and 5 is a driving belt that transmits a driving force for reciprocating the carriage 3. Reference numerals 6, 7, 8, and 9 denote a pair of conveyance rollers that are arranged before and after the print position of the print head of each head cartridge and perform nipping and conveyance of the recording medium 10. The recording medium 10 such as paper is guided and supported in a press-contact state on a platen (not shown) for regulating the printing surface to be flat at the printing position. At this time, the ejection port forming surfaces of the head cartridges 1 and 2 mounted on the carriage 3 protrude downward from the carriage 3 and are positioned between the recording medium conveying rollers 7 and 9, and are on a platen (not shown). It faces the recording medium 10 pressed against the guide surface in parallel.
[0182]
A recovery unit 11 is disposed in the vicinity of the home position set on the left side outside the print area of the ink jet printer of FIG. The recovery unit 11 includes four caps 12 corresponding to four print head cartridges 1Y, 1M, 1C, and 1B, and one liquid composition head cartridge 2. One cap 13 corresponding to the portion is provided so as to be movable up and down. When the carriage 3 is at the home position, the corresponding caps 12 and 13 are pressure-bonded to the discharge port forming surfaces of the discharge portions of the head cartridges 1 and 2, whereby the head cartridges 1 and 2. The discharge port is sealed (capped). By capping, thickening and fixing of the ink due to evaporation of the ink solvent in the discharge port is prevented, and the occurrence of defective discharge is prevented.
[0183]
The recovery unit 11 also includes a suction pump 14 that communicates with each cap 12 and a suction pump 15 that communicates with the cap 13. These pumps 14 and 15 perform suction recovery processing by capping their discharge port forming surfaces with caps 12 and 13 when a discharge failure occurs in the print head cartridge 1 or the liquid composition head cartridge 2. Used to execute. Further, the recovery unit 11 is provided with two wiping members (blades) 16 and 17 made of an elastic member such as rubber. The blade 16 is held by a blade holder 18, and the blade 17 is held by a blade holder 19.
[0184]
In the apparatus shown in the figure, the blade holders 18 and 19 are moved up and down by a blade lifting mechanism (not shown) driven by using the movement of the carriage 3, whereby the blades 16 and 17 are A position (wiping position) where the ink and foreign matter adhering to the ejection port forming surface of each of the head cartridges 1 and 2 are wiped (wiping position) and a position where the ink cartridge is not in contact with the ejection port forming surface (falling position). Go up and down between. In this case, a blade 16 for wiping the discharge port forming surface of the print head cartridge 1 (hereinafter referred to as an ink blade) and a blade 17 for wiping the discharge port forming surface of the liquid composition head cartridge 2 (hereinafter referred to as a liquid composition). The blades) are configured to be able to move up and down independently of each other.
[0185]
When the carriage 3 moves from the right side (print area side) in FIG. 1 to the home position side, or when moving from the home position side to the print area side, the blade 16 forms the ejection opening of each print head cartridge 1. The blade 17 comes into contact with the surface, the blade 17 comes into contact with the discharge port forming surface of the liquid composition discharge head 2, and wiping operation of these discharge port forming surfaces is performed by relative movement.
[0186]
FIG. 2 is a schematic perspective view showing the print head cartridge 1 having a structure in which the ink discharge section and the ink tank are integrated. The liquid composition head cartridge 2 has substantially the same configuration as the print head cartridge 1 except that the liquid to be stored and used is a liquid composition. In FIG. 2, the print head cartridge 1 has an ink tank portion 21 in the upper portion and an ink discharge portion (print head portion) 22 in the lower portion, and further, signals for driving the ink discharge portion 22 and the like. A head-side connector 23 is provided for receiving and outputting an ink remaining amount detection signal. The connector 23 is provided at a position aligned with the ink tank portion 21.
In FIG. 2, the print head cartridge 1 has a discharge port forming surface 81 on the bottom surface side (recording medium 10 side), and the discharge port forming surface 81 has a plurality of discharge ports. Discharge energy generating elements that generate energy necessary to discharge ink are disposed in the liquid path portions that communicate with the respective discharge ports.
[0187]
The print head cartridge 1 is an ink jet printing unit that performs printing by ejecting ink from an ink ejecting portion thereof, and is composed of a replaceable ink jet cartridge in which the ink ejecting portion 22 and the ink tank 21 are integrated. . This print head cartridge 1 is an ink jet printing means for ejecting ink using thermal energy, and is provided with an electrothermal converter for generating thermal energy. Further, the print head cartridge 1 ejects ink from an ejection port using a pressure change caused by bubble growth and contraction caused by film boiling caused by thermal energy applied by the electrothermal transducer, and performs printing. To do.
[0188]
FIG. 3 is a partial perspective view schematically showing the structure of the ink discharge section 22 (liquid composition discharge section 22A) of the print head cartridge 1 (liquid composition head cartridge 2). In FIG. 3, a plurality of discharges are formed at a predetermined pitch on a discharge port forming surface 81 facing a recording medium (print paper or the like) 10 with a predetermined gap (for example, about 0.5 to 2.0 mm). An electrothermal converter (such as a heating resistor) 85 for generating ink discharge energy is formed along the wall surface of each liquid passage 84 that is formed with an outlet 82 and communicates between the common liquid chamber 83 and each discharge port 82. It is arranged. The plurality of ejection ports 82 are arranged in a positional relationship such that they are aligned in a direction crossing the moving direction (main scanning direction) of the print head cartridge 1. In this way, the corresponding electrothermal converter 85 is driven (energized) based on the image signal or the discharge signal, the ink in the liquid channel 84 is boiled, and the ink is discharged from the discharge port 82 by the pressure generated at that time. A print head cartridge 1 is configured.
[0189]
Here, an ink tank that holds the ink, and a tank that holds a liquid composition, which are included in the print head cartridges 1 and 2 (for the sake of simplicity, this tank is also referred to as an ink tank). As the member constituting, those having excellent chemical resistance are preferably used because they come into contact with ink or a liquid composition. Examples of materials that satisfy the requirements and are easily available include, for example, polyolefin resins, polyvinyl chloride, polyvinylidene chloride, silicone resins, ethylene-vinyl acetate copolymers, ABS resins, polyacetals, nylons, and unsaturated polyester resins. Resin materials such as PET, aramid resin, and synthetic rubbers such as styrene butadiene rubber (SBR), butadiene rubber, chloroprene, nitrile rubber, butyl rubber, EPDM, urethane rubber, silicone rubber, acrylic rubber, epichlorohydrin rubber, and fluororubber. It is done. In addition to the chemical substances constituting these resins and synthetic rubbers, many additive aids such as stabilizers, UV absorbers and antioxidants are added in appropriate amounts depending on the purpose.
[0190]
According to the study by the present inventors, in this case, these additive components are eluted into the ink or liquid composition, and the eluted component reacts with the composition of the ink or liquid composition to remove insoluble matter. May be generated. Among the above-mentioned components, fatty acids and fatty acid derivatives are eluted into inks and liquid compositions, and are precipitated again due to changes in the environment such as temperature to form insoluble materials. Also, they are contained in inks and liquid compositions. In some cases, the dissolved ions and the eluate react with each other to generate an insoluble substance of the fatty acid salt, which may clog the filter and the ejection port and obstruct the flow of ink. In order to prevent precipitation of the eluate itself from such a member and precipitation of insoluble matter due to the reaction between the eluate and components in the ink or liquid composition, for example, addition to the resin component forming the ink tank It is effective to take measures such as reducing the agent content, selecting materials that are difficult to elute, changing the solvent composition of the ink and liquid composition, and reducing the content of reactive components in the ink and liquid composition. It is. By such means, the above-described precipitation can be suppressed.
[0191]
4 to 6 are schematic views showing the wiping operation of the ink jet printer described above. FIG. 4 shows a case where the carriage 3 moves from the print area side to the home position side. In FIG. 4, the print head cartridge 1 and the liquid composition head cartridge 2 on the carriage 4 move from the right side (print region side) toward the home position as shown in FIG. Then, as shown in (B), first, the ink blade 16 between the ink cap 12 and the liquid composition cap 13 rises, and each print head 1Y, 1M is moved along with the movement of the carriage 3. 1C and 1B are wiped sequentially.
[0192]
Further, as shown in FIG. 4C, after each print head cartridge 1 passes over the liquid composition blade 17, the liquid composition blade 17 is raised and the liquid as shown in FIG. 4D. The ejection port forming surface of the composition head cartridge 2 is wiped simultaneously. After the ink blade 16 wipes the fourth print head 1 and the liquid composition blade 17 finishes wiping the discharge part of the liquid composition head cartridge 2, the blades 16 and 17 are lowered. Wait at the standby position. In FIG. 4, the wiping is performed by the blades 16 and 17 when the carriage 3 moves from the right side (printing area) in FIG. 1 to the home position side where the recovery unit 11 is located. However, the present invention is not limited to this, and wiping may be performed when the carriage 3 moves from the home position side to the right side (print area side) as shown in FIG.
[0193]
5A, the ink blade 16 and the liquid composition blade 17 are simultaneously lifted and the carriage 3 is moved to the right (to the print region side), thereby the print head cartridge 1 and the liquid composition. The wiping of the product head cartridge 2 is simultaneously performed (B). At the same time as the wiping of the liquid composition head cartridge 2 is finished, only the liquid composition blade 17 is lowered to stand by, and the ink blade 16 is left as it is. The head cartridge 1 is wiped (C). Finally, as shown in FIG. 5D, when the wiping of all the print head cartridges 1 is completed, the ink blade 16 is lowered to complete a series of wiping operations. By adopting the wiping direction as described with reference to FIG. 5, the droplets removed by wiping and adhering to the blades 16 and 17 are scattered by the elasticity of the blades to the conveying portion of the recording medium 10, and the recording medium 10 The risk of unintentionally fouling can be eliminated.
[0194]
Further, as shown in FIG. 6, the wiping direction of the print head cartridge 1 and the wiping direction of the liquid composition head cartridge 2 may be different. In FIG. 6, for example, as shown in (A) and (B), when the carriage 3 moves from the home position side to the right side (print area side), the print head cartridge 1 is wiped by the ink blade 16 ( As shown in (C) and (D), when the carriage 3 moves from the print area side to the home position side, only the discharge part of the liquid composition head cartridge 2 is wiped by the liquid composition blade 17. Also good. By adopting such a wiping direction, ink scattered by the elastic force of the blade 16 adheres to the ejection part of the head cartridge 2 for liquid composition, or conversely, the liquid composition scattered by the elastic force of the blade 17 The inconvenience (risk) of adhering to the ejection part of the print head cartridge 1 can be eliminated or greatly reduced.
[0195]
In FIG. 1, the cap 12 for the print head cartridge 1 and the cap 13 for the liquid composition head cartridge 2 are separated and made independent (dedicated). The suction pumps 14 and 15 to be connected were also made separate (dedicated) independently for the print head cartridge 1 and for the liquid composition head cartridge 2. As a result, in the caps 12 and 13 and the pumps 14 and 15, these waste liquids can be treated without bringing the ink into contact with the liquid composition having reactivity with the ink, and high reliability is maintained. It becomes possible to do.
[0196]
FIG. 7 is a schematic diagram showing a collection system for collecting the ink and liquid composition discharged from the pumps 14 and 15 into the waste ink tank. In FIG. 7, the waste ink sucked from the print head cartridge 1 by the suction pump 14 communicated with the cap 12 and the waste liquid sucked from the liquid composition head cartridge 2 by the suction pump 15 communicated with the cap 13 The liquid is collected and stored in the waste liquid tank 24 through independent paths so as not to leak outside.
[0197]
The waste liquid tank 24 is filled with a porous absorbent body 25 and is configured to absorb and hold the waste liquid in the absorbent body 25. The waste liquid tank 24 is provided in the printer main body. In FIG. 7, the waste ink conduit 26 from the suction pump 14 for the print head cartridge 1 and the waste fluid conduit 27 from the suction pump 15 for the liquid composition head cartridge 2 are shown in FIG. The two ends are connected to positions separated from each other. By doing so, the liquid composition and the ink in the waste liquid tank 24 come into contact with each other only when the liquid is sufficiently absorbed in the absorber 25, and therefore the amount of liquid that the porous absorber 25 can absorb and hold. Can be secured sufficiently.
[0198]
FIG. 8 shows the waste liquid recovery system of FIG. 7 in which the absorber 25 in the waste liquid tank 24 is arranged in two upper and lower stages, the lower absorber 25A absorbs the ink, and the upper absorber 25B absorbs the liquid composition. It is a schematic diagram which shows the waste liquid collection | recovery system comprised so that it might make it. According to the configuration of FIG. 8, even when the lower ink absorber 25A overflows, the dye in the ink reacts with the upper absorber 25B by the upper absorber 25B and the liquid composition absorbed therein. Since the ink is fixed, the ink does not leak and stain the inside and outside of the printer.
[0199]
The ink jet recording apparatus according to another aspect of the present invention preferably includes an ink containing portion containing an anionic or cationic aqueous ink containing a coloring material, and a surface charged to a polarity opposite to that of the aqueous ink. A liquid composition container containing the liquid composition according to the present invention, in which dispersed fine particles are contained in a dispersed state, an aqueous ink stored in the ink container, and a liquid composition container And an ink jet head for independently ejecting the liquid composition. Hereinafter, an ink jet recording apparatus of this form will be described.
[0200]
FIG. 10 shows a cartridge 1001 which is an example of such an ink jet recording apparatus. In FIG. 10, reference numeral 1003 denotes an ink containing portion that contains ink, and 1005 denotes a liquid composition. The liquid composition container. As shown in FIG. 11, the cartridge is configured to be detachable from a recording head 1101 that discharges each of ink and liquid composition, and when the cartridge 1001 is mounted on the recording head 1101, the liquid composition and Ink is configured to be supplied to the recording head 1101.
[0201]
The ink jet recording apparatus of the present invention is not limited to the above-described head and the ink cartridge, but may be an integral unit as shown in FIG. In FIG. 15, reference numeral 1500 denotes a recording unit, in which an ink containing portion containing ink, for example, an ink absorber is housed, and the ink in the ink absorber has a plurality of orifices. It is configured to be ejected as ink droplets from the portion 1501. As a material of the ink absorber, for example, polypropylene or polyurethane can be used. Reference numeral 1502 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere.
[0202]
Furthermore, as another embodiment of the recording unit used in the present invention, the ink and the liquid composition are stored in each storage section in one ink tank, and each of the ink and the liquid composition is discharged. For example, as shown in FIG. 12, for example, as shown in FIG. 12, the recording unit is provided in the storage unit 1201L, the black ink is stored in the storage unit 1201Bk, and yellow, cyan, and A magenta color ink is stored in each of the color ink storage portions 1201Y, 1201M, and 1201C, and a recording head 1203 is provided that has a separate ink flow path so that these can be individually ejected. Recording unit 1201.
[0203]
FIG. 16 is a schematic perspective view showing a schematic configuration of another embodiment of the ink jet printer which is the ink jet recording apparatus of the present invention.
In FIG. 16, reference numeral 4 denotes a scanning rail that extends in the main scanning direction of the carriage 3 and slidably supports the carriage 5, and 5 denotes a driving belt that transmits a driving force for reciprocating the carriage 3. . Reference numerals 6, 7, 8, and 9 denote a pair of conveyance rollers that are arranged before and after the print position by the print head and perform nipping and conveyance of the printing material 10. The printed material 10 such as paper is guided and supported in a pressed state on a platen (not shown) for restricting the printing surface to be flat at the printing position. At this time, the ejection port forming surfaces of the head cartridges 1 and 2 mounted on the carriage 3 protrude downward from the carriage 3 and are positioned between the recording medium conveying rollers 7 and 9, and are on a platen (not shown). It faces the recording medium 10 pressed against the guide surface in parallel.
[0204]
In FIG. 16, a total of six head cartridges are positioned and mounted on the carriage 3. In this embodiment, the yellow print head cartridge 1Y and the magenta print are printed from the left end of the carriage 3 toward the right side. The head cartridge 1M, the cyan print head cartridge 1C, the black print head cartridge 1B, the liquid composition head cartridge 2, and the second black print head cartridge 1BB are arranged in this order. The liquid composition head cartridge 2 ejects the liquid composition of the present invention having reactivity with the coloring material in the ink onto the recording medium 10. The second black print head cartridge 1BB at the right end is a print head cartridge that uses black ink that is used during sub-scan printing in reciprocating printing. That is, the liquid composition head cartridge 2 is disposed next to (right next to) the black print head cartridge 1B in each of the above-described embodiments, and the black print head cartridge 1BB is disposed next (right end). The arrangement to arrange is taken.
[0205]
In FIG. 16, a recovery unit 11 is disposed on the left side of the print area. In the recovery unit 11, the print head cartridges 1Y, 1M are printed from left to right corresponding to the arrangement of the head cartridges 1 and 2. The caps 12 for capping the discharge parts 1C and 1B are sequentially arranged, and then the cap 13 for capping the discharge part of the liquid composition head cartridge 2 is arranged (next to the right). On the right end), a cap 12 for capping the ejection part of the second black print head cartridge 1BB is arranged. Each cap is provided so as to be movable up and down. When the carriage 3 is at the home position, the corresponding caps 12 and 13 are pressed against the discharge port forming surfaces of the heads 1 and 2, respectively. As a result, the ejection openings of the head cartridges 1 and 2 are sealed (capped), thereby preventing ink thickening and sticking due to evaporation of the ink solvent in the ejection openings, thereby preventing the occurrence of ejection failure.
[0206]
The recovery unit 11 also includes a suction pump 14 that communicates with the caps 1 and 2 and a suction pump 15 that communicates with the cap 13. These pumps 14 and 15 perform suction recovery processing by capping their discharge port forming surfaces with caps 12 and 13 when a discharge failure occurs in the discharge part of the print head cartridge 1 or the liquid composition head cartridge 2. Used to execute Further, a liquid composition blade 17 is disposed between the fifth liquid composition cap 13 from the left end and the sixth (right end) black ink cap 12, and the right side of the right end cap 12 ( A blade 16 for the discharge portion of each print head cartridge 1 is disposed on the print area side). The blade 17 is held by a blade holder 19, and the blade 16 is held by a blade holder 18.
[0207]
In this embodiment, the blade holder 19 is moved up and down by a blade lifting mechanism (not shown) driven by using the movement of the carriage 3, whereby the blades 16 and 17 form the ejection openings of the head cartridges 1 and 2. It moves up and down between a position (wiping position) that protrudes to wipe ink and foreign matter adhering to the surface and a retracted position (standby position) that does not contact the discharge port forming surface. In this case, the blade 16 for wiping the discharge part of the print head cartridge 1 and the blade 17 for wiping the discharge part of the liquid composition head cartridge 2 are configured to be able to move up and down independently of each other.
[0208]
FIG. 17 is a schematic diagram showing a wiping operation of the ink jet printer shown in FIG. In FIG. 16, after the pudding blade 16 protrudes (ascends), each head mounted on the carriage 3 moves from the right side (printing area side) toward the home position, as shown in FIG. . The raised ink blade 16 sequentially wipes the print head 1 as the carriage 3 moves to the left as shown in FIG. Then, as shown in (C), when the liquid composition head cartridge 2 comes to the front of the ink blade 16 (next to the right), the blade 16 retracts (lowers) to the standby position, and the blade 16 And the discharge head of the liquid composition head cartridge 2 are prevented from contacting each other.
[0209]
Further, when the carriage 3 moves to the left and the liquid composition head cartridge 2 passes through the print head blade 16, as shown in (D), the ink blade 16 and the liquid composition blade 17. Protrude (raise) both. Then, as the carriage 3 moves leftward, as shown in (E), the wiping of the liquid composition head cartridge 2 by the blade 17 and the wiping of the right end print head 1BB by the blade 16 are simultaneously performed. After the wiping of all the heads 1 and 2 is completed, as shown in (F), both the blades 16 and 17 are moved backward (lowered), and waited at the standby position.
[0210]
In the embodiment of FIGS. 16 and 17, wiping is performed by the blades 16 and 17 when the carriage 3 moves from the print area side (right side) to the home position side where the recovery unit 11 is located. However, the wiping may be performed when moving from the home position side to the right side (print area side).
[0211]
The ink jet printer of FIG. 16 discharges the liquid composition according to the present invention from the liquid composition discharge head 2 to the recording medium 10 that has reactivity with the color material in the ink, and is discharged from each print head 01. The printed material can be formed by bringing the ink into contact with the recording medium 10. On the recording medium 10, the color material in the ink reacts with the liquid composition, so that the color material in the ink is adsorbed on the surface of the fine particles in a single molecule state, and an image is formed by the fine particles. Images with excellent color uniformity can be obtained.
[0212]
In the recording apparatus used in the present invention, an ink jet recording apparatus that discharges ink droplets by applying thermal energy to the ink and the liquid composition has been described as an example. In addition, a piezo method using a piezoelectric element is also used. The present invention can also be used in the same manner.
By the way, the ink jet recording apparatus according to the present invention is not limited to the ink jet recording apparatus having the above-described configuration, and has a configuration disclosed in, for example, Japanese Patent Laid-Open No. 10-146991 and the operation of the wiping blade of the head. An ink jet recording apparatus having a direction different from that of the ink jet recording apparatus described above may be used.
[0213]
【Example】
Next, the present invention will be described more specifically with reference to examples and comparative examples. In the text, “part” and “%” are based on mass unless otherwise specified. The zeta potential in the text is determined by dispersing the liquid composition with ion-exchanged water so that the solid content concentration of the fine particles is 0.1%, and then measuring a zeta potential measuring machine (Brookhaven, BI-ZETAplus, liquid temperature). It is a value measured at 20 ° C. using an acrylic cell. Moreover, pH was measured with respect to the created liquid composition using the pH meter meter (Horiba Manufacturing Co., Ltd. product, Castany pH meter D-14) at the liquid temperature of 25 degreeC. The average particle diameter of the fine particles is obtained by dispersing the liquid composition with ion-exchanged water so that the solid content concentration of the fine particles becomes 0.1%, and then measuring the dynamic light scattering particle size distribution meter (BI manufactured by Brookhaven, BI). -90, liquid temperature 20 ° C., acrylic cell used).
[0214]
First, preparation of the liquid composition will be described. The liquid compositions A to D used in the examples were mixed and dissolved with the components described below, and then pressure filtered with a membrane filter (trade name, fluoropore filter, manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 1 μm. It was produced by. In addition, the pore radius distribution and pore volume of the liquid composition were pretreated according to the following procedures (1) to (3), and then the sample was placed in a cell and vacuum degassed at 120 ° C. for 8 hours. Measurement was performed by a nitrogen adsorption / desorption method using Omnisorb 1 manufactured by Cantachrome. The pore radius and pore volume were obtained by calculation according to the method of Barrett et al. (J. Am. Chem. Soc., Vol. 73, 373, 1951). The BET specific surface area was obtained by calculation according to the method of Brunauer et al. (J. Am. Chem. Soc., Vol. 60, 309, 1938).
(1) The liquid composition to be measured is dried at 120 ° C. for 10 hours in an air atmosphere, and the solvent is evaporated to dry.
(2) The dried product is heated to 120 to 700 ° C. over 1 hour and then baked at 700 ° C. for 3 hours.
(3) After calcination, the obtained baked product is gradually returned to room temperature, and the baked product is crushed with an agate mortar to be powdered.
[0215]
(Synthesis example of alumina hydrate)
First, aluminum dodexide was produced by the method described in US Pat. No. 4,242,271. Next, by the method described in US Pat. No. 4,202,870, the aluminum dodexide obtained above was hydrolyzed to produce an alumina slurry. Water was added to the alumina slurry until the solid content of alumina hydrate was 8.2%. The pH of the alumina slurry was 9.7. A 3.9% nitric acid solution was added to adjust the pH, and colloidal sol was obtained under each aging condition shown in Table 1. Further, the colloidal sol was spray-dried at 83 ° C. to prepare alumina hydrates A to D. All of these alumina hydrates were positively charged in water and were cationic. These alumina hydrates were dispersed in ion-exchanged water and dropped onto a collodion membrane to prepare a measurement sample. When observed with a transmission electron microscope, all were flat plate-like fine particles.
[0216]
In addition, these alumina hydrate powders were put into a cell, vacuum degassed at 120 ° C. for 8 hours, and measured by a nitrogen adsorption / desorption method using Omnisorb 1 manufactured by Cantachrome Co. The BET specific surface area was obtained from the calculation by the method (J. Am. Chem. Soc., Vol. 60, 309, 1938). The BET specific surface areas of the obtained alumina hydrates A to D are shown in Table 1.
[0217]

[0218]

[0219]
The pH of the liquid composition A obtained above was 3.8, and the zeta potential was +35 mV. In addition, an ink tank of the same type as the ink tank for BJF8500 made by Canon (BCI-8WF) was filled with the liquid composition A, and a storage test was conducted at 60 ° C./Dry·1 month. After storage, the ink tank settled in the ink tank. No matter was seen, and the ejection stability from the recording head when this ink tank was mounted on a Canon printer BJF8500 was also good. In addition, the fine particle aggregate obtained from the liquid composition A after the pretreatment according to the procedures (1) to (3) described above has a pore volume of 0 in the range of the pore radius of 3 nm to 30 nm. The pore volume in the range exceeding 30 nm was 0.015 ml / g. The pore volume in the range of 3 nm to 20 nm was 0.88 ml / g, and the pore volume in the range exceeding 20 nm was 0.09 ml / g. The fine particle aggregate has a BET specific surface area of 74 m. ² / G.
[0220]

[0221]
The pH of the liquid composition B obtained above was 3.7, and the zeta potential was +37 mV. In addition, when a liquid composition B was filled into an ink tank of the same type as a Canon BJF8500 ink tank (BCI-8WF) and a storage test was conducted at 60 ° C./Dry·1 month, sediment was found in the ink tank. The ejection stability from the recording head when this ink tank was mounted on a Canon printer BJF8500 was also good. In addition, the fine particle aggregate obtained after the pretreatment according to the procedures (1) to (3) described above from the liquid composition B has a pore volume of 0 to 3 in the range of the pore radius of 3 nm to 30 nm. The pore volume in the range exceeding 30 nm was 0.009 ml / g. The pore volume in the range of 3 nm to 20 nm was 0.91 ml / g, and the pore volume in the range exceeding 20 nm was 0.015 ml / g. The BET specific surface area of the fine particle aggregate is 103 m. ² / G.
[0222]

[0223]
The pH of the liquid composition C obtained above was 3.7, and the zeta potential was +40 mV. In addition, when a liquid composition C was filled in an ink tank of the same type as a Canon BJF8500 ink tank (BCI-8WF) and a storage test was conducted at 60 ° C./Dry·1 month, sediment was found in the ink tank. The ejection stability from the recording head when this ink tank was mounted on a Canon printer BJF8500 was also good. In addition, the fine particle aggregate obtained after the pretreatment according to the procedures (1) to (3) described above from the liquid composition C has a pore volume of 0 to within a pore radius range of 3 nm to 30 nm. The pore volume in the range exceeding 30 nm was 0.001 ml / g. The pore volume in the range of 3 nm to 20 nm was 0.50 ml / g, and the pore volume in the range exceeding 20 nm was 0.007 ml / g. The fine particle aggregate has a BET specific surface area of 192 m. ² / G.
[0224]

[0225]
The pH of the liquid composition D obtained above was 3.7, and the zeta potential was +40 mV. In addition, when a liquid composition D was filled in an ink tank of the same type as a Canon BJF8500 ink tank (BCI-8WF) and a storage test was performed at 60 ° C./Dry·1 month, sediment was found in the ink tank. The ejection stability from the recording head when this ink tank was mounted on a Canon printer BJF8500 was also good. In addition, the fine particle aggregate obtained after the pretreatment according to the procedures (1) to (3) described above from the liquid composition C has a pore volume of 0 to within a pore radius range of 3 nm to 30 nm. The pore volume in the range exceeding 30 nm was 0.001 ml / g. The pore volume in the range of 3 nm to 20 nm was 0.38 ml / g, and the pore volume in the range exceeding 20 nm was 0.027 ml / g. The BET specific surface area of the fine particle aggregate is 215 m. ² / G.
[0226]
Next, the production of ink subsets 1 and 2 used in the examples and comparative examples of the present invention will be described.
<Preparation of ink subset 1>
The components shown below were mixed, sufficiently stirred and dissolved, and then filtered under pressure with a fluoropore filter (trade name, manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 0.45 μm, and black, yellow, magenta and cyan The dye inks Bk1, Y1, M1 and C1 were obtained, and the combination of these dye inks was designated as ink subset 1.
[0227]

[0228]

[0229]

[0230]

[0231]
<Preparation of ink subset 2>
A pigment dispersion was prepared from the components shown below, and a black ink Bk2 was produced using the pigment dispersion. Further, yellow, magenta, and cyan pigment inks Y2, M2, and C2 were obtained using the pigment dispersion liquids of the respective colors obtained in the same manner as described above except that the color material was changed. A combination of these pigment inks Bk2, Y2, M2, and C2 was designated as ink subset 2.
[0232]
[Black ink Bk2]
(Preparation of pigment dispersion)
・ Styrene-acrylic acid-ethyl acrylate copolymer
(Acid value 140, weight average molecular weight 5,000) 1.5 parts
・ 1.0 parts of monoethanolamine
・ Diethylene glycol 5.0 parts
・ Ion exchange water 81.5 parts
[0233]
The above components are mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. To this solution, 10 parts of newly produced carbon black (MCF88, manufactured by Mitsubishi Kasei) and 1 part of isopropyl alcohol were added, premixed for 30 minutes, and then dispersed under the following conditions.
・ Disperser: Sand grinder (Igarashi Machine)
・ Crushing media: Zirconium beads, 1 mm diameter
・ Filling rate of grinding media: 50% (volume ratio)
・ Crushing time: 3 hours
Furthermore, centrifugal separation (12,000 rpm, 20 minutes) was performed to remove coarse particles to obtain a pigment dispersion.
[0234]
(Preparation of black ink Bk2)
Using the above pigment dispersion, components having the following composition ratios were mixed to prepare an ink containing a pigment, which was designated as black ink Bk2.
-30.0 parts of the above pigment dispersion
・ Glycerin 10.0 parts
・ Ethylene glycol 5.0 parts
・ N-methylpyrrolidone 5.0 parts
・ 2.0 parts of ethyl alcohol
・ Ion exchange water 48.0 parts
[0235]
[Yellow ink Y2]
A pigment-containing yellow ink Y2 was prepared in the same manner as the black ink Bk2, except that 10 parts of carbon black (MCF88, manufactured by Mitsubishi Kasei) used in the preparation of the black ink Bk2 was replaced with pigment yellow 74. .
[0236]
[Magenta ink M2]
A pigment-containing magenta ink M2 was prepared in the same manner as the black ink Bk2, except that 10 parts of carbon black (MCF88, manufactured by Mitsubishi Kasei) used in the preparation of the black ink Bk2 was replaced with Pigment Red 7. .
[0237]
[Cyan ink C2]
A pigment-containing cyan ink C2 was prepared in the same manner as the black ink Bk2, except that 10 parts of carbon black (MCF88, manufactured by Mitsubishi Kasei) used in the preparation of the black ink Bk2 was replaced with pigment blue 15. .
[0238]
(Example 1 to Example 8)
The liquid compositions A to D of the present invention obtained as described above, the ink subset 1 (Bk1, Y1, M1, and C1), and the ink subset 2 (Bk2, Y2, M2, and C2) are set. Using this, printing was performed in the combinations shown in Table 2 below. This was set as Examples 1 to 8 of the present invention.
[0239]

[0240]
In the method for forming colored portions of Examples 1 to 8 using the liquid compositions A to D and the ink subsets 1 and 2 in combination as described above, recording was performed on PPC paper (manufactured by Canon). Further, as the ink jet recording apparatus used at that time, a recording apparatus similar to that shown in FIG. 1 was used, and a color image was formed using five recording heads shown in FIG. Specifically, using a modified printer of Canon printer BJF800, the liquid composition was filled in an ink tank of plain paper water-resistant reinforcing agent, and each ink was filled in an ink tank corresponding to each color to form an image. . At this time, the liquid composition was preliminarily deposited on the PPC paper, and then the ink was adhered.
[0241]
Then, two-pass fine printing was performed in which the print area was printed by two scans to form an image. At this time, the liquid composition was printed at each pixel position on which any one of yellow, magenta, cyan, and black ink was printed for each pass. That is, the logical sum of yellow, magenta, cyan and black print data for each pass was used as print data for the liquid composition. There are no particular restrictions on the type of fine mask at the time of fine printing, and a known technique can be used, so detailed description thereof is omitted here.
[0242]
The recording head used here had a recording density of 600 dpi, and the driving condition was a driving frequency of 9.6 kHz. When a 600 dpi head was used, the discharge amount per dot was 15 ng for each of yellow, magenta, and cyan inks and the liquid composition, and 30 ng for each black ink. These recording conditions are the same throughout the examples and comparative examples.
[0243]
(Comparative Examples 1 and 2)
Using only ink subsets 1 and 2, printing was performed as shown in Table 3 below.

[0244]
In the recording using only the ink subset 1 and the ink subset 2 (Comparative Examples 1 and 2), the recording head has a recording density of 600 dpi, and the driving frequency is 9.6 kHz. When a 600 dpi recording head is used, the discharge amount per dot is about 15 ng for yellow, magenta and cyan inks, and about 30 ng per dot for black ink. Recording was performed under the same conditions as in the case.
[0245]
[Evaluation method and evaluation criteria]
Each recorded image obtained in Examples 1 to 8 and Comparative Examples 1 and 2 was evaluated by the following evaluation method and evaluation criteria. Table 4 summarizes the results.
[0246]
(Evaluation method of recorded image)
(1) Color development
RGB color charts of high-definition XYZ / CIELAB / RGB standard images (SHIPP) (supervision: High-definition standard image creation committee, published by the Institute of Image Electronics Engineers of Japan) were printed using a printer, and the color charts were measured. The evaluation of color development was carried out by calculating the three-dimensional spread of the color distribution (hereinafter referred to as the color gamut volume in the text) by the method described in the technical manual and compared. At that time, the image processing at the time of forming the printed image was made under the same conditions, and the colorimetry was measured under the conditions of light source: D50, field of view: 2 ° with GRETAG Spectrolino after 24 hours had elapsed after printing. The evaluation criteria are shown below. The ratio of the color gamut volume to the printed image of only the ink subset (Comparative Examples 1 and 2) was used as an evaluation criterion.
[0247]
AAA: Color gamut volume ratio is 1.7 times or more
AA: Color gamut volume ratio is less than 1.5 to 1.7 times
A: Color gamut volume ratio is less than 1.4 to 1.5 times
BB: Color gamut volume ratio is less than 1.2 to 1.4 times
B: Color gamut volume ratio is less than 1.0 to 1.2 times
C: Color gamut volume ratio is less than 1.0 times
[0248]
Separately from this, an ink-coated paper (trade name: Color BJ paper LC-101, manufactured by Canon Inc.) was used to print with ink subset 1 to form an image. The ratio of the color gamut volume to the product was determined to be 1.3 times.
[0249]
(2) Uniformity
Using the printer described above, solid images of yellow, magenta, cyan, and black inks were printed, and color uniformity was evaluated visually with respect to white fog and color unevenness. At this time, particularly poorly uniform colors were evaluated. The evaluation criteria are as follows.
A: White haze and color unevenness hardly occur.
B: Some white haze and color unevenness can be seen along the fibers of the paper.
C: Remarkable white haze and color unevenness are visible along the paper fibers.
[0250]
(3) Sujimura
After printing a solid image of yellow, magenta, cyan, and black inks using the printer described above, the unevenness was visually evaluated. At this time, particularly unfavorable colors were evaluated. The evaluation criteria are as follows.
A: Almost no streaks occur.
B: Although slight unevenness can be seen for each head scan, it is a level with no problem.
C: Remarkably white stripes are visible at every head scan.
[0251]
(4) Texture
Using the printer described above, solid images of yellow, magenta, cyan, and black inks were printed, and the texture of the recording medium was visually evaluated. The evaluation criteria are as follows.
A: Both the printed part and the unprinted part have no sense of incongruity and leave the texture of plain paper.
B: The texture is different between the printed portion and the unprinted portion, or the entire recording medium is greatly different from the texture of plain paper.
[0252]
(5) Bleed
Using the printer described above, solid images of cyan and black were printed adjacent to each other, and then bleed at the boundary between colors was visually observed and evaluated according to the following criteria.
AA: Bleeding cannot be visually recognized.
A: Bleeding is hardly noticeable.
B: Although bleeding is occurring, the level is substantially free of problems.
C: The color boundary paper is bleeding so that it is not clear.
[0253]
(6) Character quality
Black text was printed using the printer described above, and the degree of character quality was visually observed. The evaluation criteria are as follows.
A: The text is sharply reproduced, and feathering and character fatness hardly occur.
B: Feathering occurs slightly, but at a level where there is practically no problem.
C: Other than the above.
[0254]

[0255]
(Examples 9 to 15)
In order to investigate the influence on the image quality due to the type of recording medium to be used, the liquid composition B and the ink subset 1 created above are widely distributed under the trade names 1) to 7) below. The types of “plain paper” were used, and on these plain papers, each of the four color inks constituting the ink subset 1 and the liquid composition B were printed in the same manner as in the above examples, and the recording of Examples 9 to 15 An image was formed. This image was evaluated based on the evaluation criteria described above. The obtained results are shown in Table 5 below.
[0256]
Recording medium
1) Canon: PB paper
2) Canon: Brilliant Whitepaper
3) Made by Union Camp: Great White Inkjet
4) Hammermill company: JetPrint
5) Xerox 4024 manufactured by Xerox
6) Hewlett Packard: Bright White Inkjet Paper
7) AussdatRay: RayJet
[0257]

[0258]
As a result of the above, in the colored portion forming methods of Examples 9 to 15, as shown in Table 5, regardless of the type of the recording material, the coloring property and uniformity are excellent, and unevenness and bleeding are generated. It was confirmed that satisfactory images could be obtained in both texture and character quality.
[0259]
【The invention's effect】
As described above, according to the present invention, particularly when color ink jet recording is performed on plain paper, excellent color developability and color uniformity comparable to those of coated paper for ink jet while leaving the texture of plain paper, and Liquid composition, ink set, method for forming a colored portion on a recording medium, and ink jet, which are excellent in character quality in which occurrence of bleeding at a color boundary portion is suppressed and in which an ink jet recording image with little unevenness in a solid image portion is obtained A recording device is provided. Moreover, according to the present invention, there is provided a liquid composition excellent in ink jet recording characteristics that is excellent in storage stability and ejection stability from a recording head.
[Brief description of the drawings]
FIG. 1 is a partially broken perspective view schematically showing an ink jet printer to which the present invention is applied.
FIG. 2 is a schematic perspective view of the head cartridge in FIG.
3 is a partial perspective view schematically showing a structure of an ink discharge portion of the head cartridge in FIG. 1. FIG.
4A and 4B are schematic diagrams illustrating a wiping operation of the ink jet printer of FIG. 1, wherein FIG. 4A is a movement of each head from the print area side to the home position and an ink blade is lifted, and FIG. 4B is a wiping of the print head. , (C) shows the wiping of the liquid composition discharge head, and (D) shows the lowering of each blade.
5A and 5B are schematic diagrams illustrating a wiping operation of the ink jet printer of FIG. 1, in which (A) is a rise of each blade, (B) is a movement of each head from the home position to the print area side, and (C) is a liquid. The lowering of the composition blade, (D) shows the wiping of the print head and the lowering of the ink blade, respectively.
6 is a schematic diagram illustrating a wiping operation of the ink jet printer of FIG. 1, in which (A) is a rise of an ink blade, (B) is a movement of each head from a home position side to a print area side and a print head side. Wiping, (C) is the movement of each head from the print area side to the home position side, the standby of the ink blade and the rising of the blade for liquid composition, (D) the movement of each head to the home position side and the liquid composition The wiping of the discharge head is shown respectively.
7 is a schematic diagram showing a waste liquid recovery system of the ink jet printer of FIG. 1. FIG.
FIG. 8 is a schematic diagram showing a partial modification of the waste liquid recovery system in FIG.
FIG. 9 is a schematic cross-sectional view illustrating a state of a colored portion when ink jet recording is performed on a coated paper.
FIG. 10 is a schematic view showing an embodiment of an ink cartridge according to the present invention.
11 is a schematic diagram of a recording head equipped with the ink cartridge of FIG.
FIG. 12 is a schematic diagram showing an embodiment of a recording unit according to the present invention.
FIG. 13 is a schematic cross-sectional view illustrating a state of a colored portion of an inkjet image according to the present invention.
FIG. 14 is a schematic process diagram showing a process for forming a colored portion of an inkjet recorded image according to the present invention.
FIG. 15 is a perspective view of a recording unit.
FIG. 16 is a partially broken perspective view schematically showing one embodiment of the ink jet printer according to the present invention.
17 is a schematic diagram illustrating a wiping operation of the ink jet printer of FIG. 16, where (A) is a rise of an ink blade, (B) is a wiping of a print head, (C) is a descent of an ink blade, (D ) Shows the rising of both blades after the liquid composition is in the proper position, (E) shows the wiping of the liquid composition and the second black ink head, and (F) shows the lowering of both blades.
[Explanation of symbols]
1: Print head cartridge)
2: Head cartridge for liquid composition
3: Carriage
4: Guide shaft (scanning rail)
5: Drive belt
6, 7: Conveyance roller
8, 9: Conveying roller
10: Recording medium
11: Recovery unit
12: Cap (for ink)
13: Cap (for liquid composition)
14: Suction pump (for ink)
15: Suction pump (for liquid composition)
16: Blade (for ink)
17: Blade (for liquid composition)
18: Blade holder (for blade 16)
19: Blade holder (for blade 17)
21: Liquid storage tank
22: (ink) ejection part
22A: (Liquid composition) discharge part
23: Head side connector
24: Waste liquid tank
25: Absorber
25A: Ink absorber
25B: Liquid composition absorber
26: Waste ink conduit
27: Waste liquid conduit
81: Discharge port forming surface
82: Discharge port
83: Common liquid chamber
84: Liquid channel
85: Electrothermal converter (heating resistor, etc.)
901: Base paper
903: Ink receiving layer
905: Porous fine particles
907: Adhesive
909: Ink penetration part
1001: Cartridge
1003: Ink container
1005: Liquid composition container
1101: Recording head
1201: Recording unit
1201Y: Yellow ink container
1201M: Magenta ink container
1201C: Cyan ink container
1201L: Liquid composition container
1201Bk: Black ink container
1203: Recording head
1301: Recording medium
1302: Gaps between fibers of the recording medium
1303: Fine particles
1305: Color material
1307: Aggregate of fine particles (holding colorant)
1309: Aggregate of fine particles (near fibers of recording medium)
I: Colored part
IM: Main image part
IS: Peripheral part
1400: Colored part
1401: Reaction part
1402: Ink outflow portion
1403: Recording medium
1404: Color material
1405: Gaps between fibers of the recording medium
1406: Liquid composition
1407: Liquid pool
1409: Fine particles
1411: Collection of fine particles
1413: Ink
1415: Aggregate of fine particles to which coloring material is attached
1500: Recording unit
1501: Head part
1502: Air communication hole

Claims (16)

Anionic aqueous ink (except when containing resin emulsion particles) containing a coloring material was in the liquid composition used in conjunction with being applied to the recording medium to form colored portions on該被recording medium Te, the liquid composition comprises at least a solvent, are charged surface in the opposite polarity to the aqueous ink, and alumina hydrate fine particles reactive with the colorant, and, said liquid Liquid having a specific surface area of 70 to 250 m ² / g determined by BET nitrogen adsorption / desorption method for fine particle aggregates formed from the product according to the following steps (1) to (4) Composition:
(1) A step of drying the liquid composition at 120 ° C. for 10 hours in an air atmosphere;
(2) The temperature of the dried product is raised to 120 to 700 ° C. over 1 hour and then calcined at 700 ° C. for 3 hours;
(3) A step of gradually cooling the fired product obtained in the step (2) to room temperature and then pulverizing it; and (4) vacuuming the powder obtained in the step (3) at 120 ° C. for 8 hours. A step of deaeration to obtain a fine particle aggregate.   The liquid composition according to claim 1, wherein the fine particles are fine particles that adsorb the coloring material on the surface of the fine particles while preventing aggregation of the coloring material in the ink when forming the colored portion.   The liquid composition according to claim 1, wherein the zeta potential is +5 to +90 mV.   Furthermore, the liquid composition of any one of Claims 1-3 in which the primary dissociation constant pKa in water contains the acid which is 5 or less, and pH is adjusted to 2-7. The liquid composition according to any one of claims 1 to 4 , wherein the average particle diameter of the fine particles is in the range of 0.005 to 1 µm. The specific surface area of the fine particles, the liquid composition according to any one of claims 1 to 5 which is a 70~300m ² / g. 2. An ink set comprising an anionic ink containing a coloring material and a liquid composition containing fine particles having reactivity with the coloring material, wherein the liquid composition is the liquid composition according to claim 1. An ink set characterized by The ink set according to claim 7 , wherein the ink is at least one selected from the group consisting of yellow ink, magenta ink, cyan ink, black ink, red ink, blue ink, and green ink. The ink set according to claim 7 or 8 zeta potential of the liquid composition is a +. 5 to + 90 mV. Primary dissociation constant pKa of the liquid composition is in water, containing 5 following acids ink according to any one of claims 7 to 9, the pH is adjusted to 2 to 7 of the liquid composition set. The ink set according to any one of claims 7 to 10 , wherein an average particle diameter of the fine particles dispersed in the liquid composition is in a range of 0.005 to 1 µm. The ink set according to any one of claims 7 to 11, wherein the specific surface area of the fine particles is 70 to 300 m ² / g. The ink set according to any one of claims 7 to 12, wherein the ink contains any of the following i) to iii): i) a water-soluble dye having an anionic group;
ii) a pigment and an anionic compound which is a dispersant for the pigment,
iii) A pigment in which an anionic group is bonded to the pigment surface directly or through another atomic group. The ink set according to any one of claims 7-1 3 wherein the liquid composition and the ink is for inkjet recording. A method of forming a colored portion on a recording medium comprising the step (i) of applying an ink containing a coloring material to a recording medium and the step (ii) of applying a liquid composition to the recording medium, forming a colored portion on a recording medium, wherein each of the ink and the liquid composition is an ink and the liquid composition constituting the ink set according to any one of claims 7-1 4 Method. Ink jet recording method in which at least one of application of ink to recording medium in step (i) and application of liquid composition to recording medium in step (ii) is performed by ejecting ink from an orifice in accordance with a recording signal The method for forming a colored portion on a recording medium according to claim 15 , wherein

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