JP2005007792A - Inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording method excellent in gas fading resistance, gloss properties, a tint of gloss reflected light, and beading resistance of an image. <P>SOLUTION: This inkjet recording method is characterized in that the image is recorded by ejecting a water-based dye ink, containing ionic resin particles, to an inkjet recording medium with a recoding layer not containing an ionic mordant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４２】
一般式（１）において、Ｒは水素原子またはアルキル基を表し、Ｒ_１、Ｒ_２、Ｒ_３は各々アルキル基またはベンジル基を表し、Ｊは単なる結合手または２価の有機基を表す。Ｘ⁻はアニオン基を表す。
【００４３】
前記一般式（１）において、Ｒで表されるアルキル基としては、メチル基が好ましい。Ｒ_１、Ｒ_２、およびＲ_３で表されるアルキル基は、好ましくはメチル基、エチル基またはベンジル基である。Ｊで表される２価の有機基としては、好ましくは−ＣＯＮ（Ｒ′）−を表す。Ｒ′は水素原子またはアルキル基を表す。
【００４４】
Ｘで表されるアニオン基は、例えば、ハロゲンイオン、酢酸イオン、メチル硫酸イオン、ｐ−トルエンスルホン酸塩などを挙げることができる。
【００４５】
好ましいカチオン性ポリマーは、前記一般式（１）で表される繰り返し単位からなるホモポリマーであってもよく、他の共重合可能な単量体との共重合であってもよい。共重合可能な繰り返し単位としては、前記一般式（１）以外のカチオン性単量体および、カチオン性基を有しない単量体を挙げることができる。
【００４６】
カチオン性基を有する単量体としては、例えば、下記の繰り返し単位を挙げることができる。
【００４７】
【化２】

【００４８】
カチオン性基を有しない共重合可能な繰り返し単位としては、例えば、エチレン、スチレン、ブタジエン、メチルメタクリレート、エチルメタクリレート、プロピルメタクリレート、ブチルメタクリレート、オクチルメタクリレート、メチルアクリレート、エチルアクリレート、プロピルアクリレート、ブチルアクリレート、オクチルアクリレート、ヒドロキシルエチルメタクリレート、アクリルアミド、酢酸ビニル、ビニルメチルエーテル、塩化ビニル、４−ビニルピリジン、Ｎ−ビニルピロリドン、Ｎ−ビニルイミダゾール、アクリルニトリルなどを挙げることができる。
【００４９】
本発明で好ましく用いられるカチオン性ポリマーが、前記一般式（１）で表される繰り返し単位を有する場合、前記一般式（１）で表される繰り返し単位は、好ましくは２０モル％以上、特に好ましくは４０〜１００モル％である。
【００５０】
本発明に係る一般式（１）で表される繰り返し単位を有するカチオン性ポリマーの具体例を以下に示すが、本発明はこれらに限定されるものではない。
【００５１】
【化３】

【００５２】
【化４】

【００５３】
【化５】

【００５４】
上記カチオン性ポリマーの平均分子量は、概ね３０００〜２０万であり、好ましくは５０００〜１０万である。平均分子量は、ゲルパーミエーションクロマトグラフィーから求められたポリエチレングリコール換算の値で表す。
【００５５】
本発明に係るカチオン性ポリマーの使用量は、記録用紙１ｍ^２当たり、概ね０．１〜１０ｇ、好ましくは０．２〜５ｇである。
【００５６】
本発明に係る表層には、上記構成に加えて、水溶性バインダーを適宜含有することができる。
【００５７】
水溶性バインダーとしては、例えば、ポリビニルアルコール、ゼラチン、ポリエチレンオキサイド、ポリビニルピロリドン、ポリアクリル酸、ポリアクリルアミド、ポリウレタン、デキストラン、デキストリン、カラーギーナン（κ、ι、λ等）、寒天、プルラン、水溶性ポリビニルブチラール、ヒドロキシエチルセルロース、カルボキシメチルセルロース等が挙げられる。これらの水溶性樹脂は二種以上併用することも可能である。
【００５８】
本発明で好ましく用いられる水溶性樹脂は、ポリビニルアルコールである。本発明で好ましく用いられるポリビニルアルコールには、ポリ酢酸ビニルを加水分解して得られる通常のポリビニルアルコールの他に、末端をカチオン変性したポリビニルアルコールやアニオン性基を有するアニオン変性ポリビニルアルコール等の変性ポリビニルアルコールも含まれる。
【００５９】
酢酸ビニルを加水分解して得られるポリビニルアルコールは、平均重合度が１，０００以上のものが好ましく用いられ、特に、平均重合度が１，５００〜５，０００のものが好ましく用いられる。ケン化度は７０〜１００％のものが好ましく、８０〜９９．５％のものが特に好ましい。
【００６０】
カチオン変性ポリビニルアルコールとしては、例えば、特開昭６１−１０４８３号公報に記載されているような、第一〜三級アミノ基や第四級アンモニウム基を上記ポリビニルアルコールの主鎖または側鎖中に有するポリビニルアルコールであり、カチオン性基を有するエチレン性不飽和単量体と酢酸ビニルとの共重合体をケン化することにより得られる。
【００６１】
カチオン性基を有するエチレン性不飽和単量体としては、例えば、トリメチル−（２−アクリルアミド−２，２−ジメチルエチル）アンモニウムクロライド、トリメチル−（３−アクリルアミド−３，３−ジメチルプロピル）アンモニウムクロライド、Ｎ−ビニルイミダゾール、Ｎ−ビニル−２−メチルイミダゾール、Ｎ−（３−ジメチルアミノプロピル）メタクリルアミド、ヒドロキシルエチルトリメチルアンモニウムクロライド、トリメチル−（２−メタクリルアミドプロピル）アンモニウムクロライド、Ｎ−（１，１−ジメチル−３−ジメチルアミノプロピル）アクリルアミド等が挙げられる。
【００６２】
カチオン変性ポリビニルアルコールのカチオン変性基含有単量体の比率は、酢酸ビニルに対して０．１〜１０モル％、好ましくは０．２〜５モル％である。
【００６３】
アニオン変性ポリビニルアルコールは、例えば、特開平１−２０６０８８号公報に記載されているようなアニオン性基を有するポリビニルアルコール、特開昭６１−２３７６８１号公報、同６３−３０７９７９号公報に記載されているようなビニルアルコールと水溶性基を有するビニル化合物との共重合体及び特開平７−２８５２６５号公報に記載されているような水溶性基を有する変性ポリビニルアルコールが挙げられる。
【００６４】
また、ノニオン変性ポリビニルアルコールとしては、例えば、特開平７−９７５８号公報に記載されているようなポリアルキレンオキサイド基をビニルアルコールの一部に付加したポリビニルアルコール誘導体、特開平８−２５７９５号公報に記載された疎水性基を有するビニル化合物とビニルアルコールとのブロック共重合体等が挙げられる。
【００６５】
ポリビニルアルコールは、重合度や変性の種類違いなど二種類以上を併用することもできる。
【００６６】
記録層に用いられる無機微粒子の添加量は、要求されるインク吸収容量、記録層の空隙率、無機微粒子の種類、水溶性樹脂の種類に大きく依存するが、一般にはインクジェット記録媒体１ｍ^２当たり、通常、５〜３０ｇ、好ましくは１０〜２５ｇである。
【００６７】
また、記録層に用いられる無機微粒子と水溶性樹脂の比率は、質量比で通常２：１〜２０：１であり、特に３：１〜１０：１であることが好ましい。
【００６８】
記録層に用いられるイオン性樹脂は、インクジェット記録媒体１ｍ^２当たり通常０．１〜１０ｇ、好ましくは０．２〜５ｇの範囲で用いられる。
【００６９】
記録層において、空隙の総量（空隙容量）は記録媒体１ｍ^２当り２０ｍｌ以上であることが好ましい。空隙容量が２０ｍｌ／ｍ^２未満の場合、印字時のインク量が少ない場合には、インク吸収性は良好であるものの、インク量が多くなるとインクが完全に吸収されず、画質を低下させたり、乾燥性の遅れを生じるなどの問題が生じやすい。
【００７０】
本発明においては、前述の最外層及び最外層以外の層の空隙率が３０〜７０％であることが好ましい。
【００７１】
空隙率は、一つの方法としては、以下の式に従って求めることができる。
空隙率＝１００×〔（全乾燥膜厚−塗布固形分膜厚）／（全乾燥膜厚）〕
また、下記の方法によっても、空隙率を測定することができる。例えば、１００μｍポリエチレンテレフタレート上に、記録層を塗布し、ブリストー測定による飽和転移量、あるいは吸水量測定などによっても簡易に求めることができる。
【００７２】
次いで、本発明に係るインクジェット記録媒体で用いる支持体について説明する。
【００７３】
本発明で用いる支持体としては、従来からインクジェット記録媒体に用いられている支持体、例えば、普通紙、アート紙、コート紙およびキャストコート紙などの紙支持体、プラスチック支持体、両面をポリオレフィンで被覆した紙支持体、これらを張り合わせた複合支持体を用いることができるが、本発明の効果をより発揮させる観点から、非吸水性支持体を用いることが好ましい。
【００７４】
本発明において用いられる非吸水性支持体としては、プラスチック樹脂フィルム支持体、あるいは紙の両面をプラスチック樹脂フィルムで被覆した支持体が挙げられる。プラスチック樹脂フィルム支持体としては、例えば、ポリエステルフィルム、ポリ塩化ビニルフィルム、ポリプロピレンフィルム、セルローストリアセテートフィルム、ポリスチレンフィルムあるいはこれらの積層したフィルム支持体等が挙げられる。これらのプラスチック樹脂フィルムは、透明又は半透明なものも使用できる。
【００７５】
本発明において、特に好ましい支持体は、紙の両面をプラスチック樹脂で被覆した支持体であり、最も好ましいのは紙の両面をポリオレフィン樹脂で被覆した支持体である。
【００７６】
以下、本発明で特に好ましい支持体である紙の両面をポリオレフィン樹脂で被覆した支持体について説明する。
【００７７】
本発明に係る支持体に用いられる紙は、木材パルプを主原料とし、必要に応じて木材パルプに加えてポリプロピレン等の合成パルプあるいはナイロンやポリエステル等の合成繊維を用いて抄紙される。木材パルプとしてはＬＢＫＰ、ＬＢＳＰ、ＮＢＫＰ、ＮＢＳＰ、ＬＤＰ、ＮＤＰ、ＬＵＫＰ、ＮＵＫＰのいずれも用いることができるが短繊維分の多いＬＢＫＰ、ＮＢＳＰ、ＬＢＳＰ、ＮＤＰ、ＬＤＰをより多く用いることが好ましい。ただし、ＬＢＳＰ及び／またはＬＤＰの比率は１０〜７０％が好ましい。上記パルプは、不純物の少ない化学パルプ（硫酸塩パルプや亜硫酸塩パルプ）が好ましく用いられ、また漂白処理を行って白色度を向上させたパルプも有用である。
【００７８】
紙中には、例えば、高級脂肪酸、アルキルケテンダイマー等のサイズ剤、炭酸カルシウム、タルク、酸化チタン等の白色顔料、スターチ、ポリアクリルアミド、ポリビニルアルコール等の紙力増強剤、蛍光増白剤、ポリエチレングリコール類等の水分保持剤、分散剤、４級アンモニウム等の柔軟化剤等を適宜添加することができる。
【００７９】
抄紙に使用するパルプの濾水度は、ＣＳＦの規定で２００〜５００ｍｌが好ましく、また、叩解後の繊維長がＪＩＳ Ｐ ８２０７に規定される２４メッシュ残分と４２メッシュ残分の和が３０〜７０％が好ましい。なお、４メッシュ残分は２０％以下であることが好ましい。
【００８０】
紙の坪量は５０〜２５０ｇが好ましく、特に、７０〜２００ｇが好ましい。紙の厚さは５０〜２１０μｍが好ましい。
【００８１】
紙は、抄紙段階または抄紙後にカレンダー処理して高平滑性を与えることもできる。紙密度は０．７〜１．２ｇ／ｃｍ^３（ＪＩＳ Ｐ ８１１８）が一般的である。更に原紙剛度はＪＩＳ Ｐ ８１４３に規定される条件で２０〜２００ｇが好ましい。
【００８２】
紙表面には表面サイズ剤を塗布してもよく、表面サイズ剤としては前記原紙中に添加できるのと同様のサイズ剤を使用できる。
【００８３】
紙のｐＨは、ＪＩＳ Ｐ ８１１３で規定された熱水抽出法により測定された場合、ｐＨ５〜９であることが好ましい。
【００８４】
次に、この紙の両面を被覆するポリオレフィン樹脂について説明する。
この目的で用いられるポリオレフィン樹脂としては、ポリエチレン、ポリプロピレン、ポリイソブチレン、ポリエチレンが挙げられるが、プロピレンを主体とする共重合体等のポリオレフィン類が好ましく、ポリエチレンが特に好ましい。
【００８５】
以下、特に好ましいポリエチレンについて説明する。
紙表面及び裏面を被覆するポリエチレンは、主として低密度のポリエチレン（ＬＤＰＥ）及び／または高密度のポリエチレン（ＨＤＰＥ）であるが、他のＬＬＤＰＥやポリプロピレン等も一部使用することができる。
【００８６】
特に、塗布層側のポリオレフィン層は、ルチルまたはアナターゼ型の酸化チタンをその中に添加し、不透明度及び白色度を改良したものが好ましい。酸化チタン含有量はポリオレフィンに対して概ね１〜２０％、好ましくは２〜１５％である。
【００８７】
ポリオレフィン層中には白地の調整を行うための耐熱性の高い着色顔料や蛍光増白剤を添加することができる。
【００８８】
着色顔料としては、例えば、群青、紺青、コバルトブルー、フタロシアニンブルー、マンガンブルー、セルリアン、タングステンブルー、モリブデンブルー、アンスラキノンブルー等が挙げられる。
【００８９】
蛍光増白剤としては、例えば、ジアルキルアミノクマリン、ビスジメチルアミノスチルベン、ビスメチルアミノスチルベン、４−アルコキシ−１，８−ナフタレンジカルボン酸−Ｎ−アルキルイミド、ビスベンズオキサゾリルエチレン、ジアルキルスチルベン等が挙げられる。
【００９０】
紙の表裏のポリエチレンの使用量は、記録層の膜厚やバック層を設けた後で低湿及び高湿化でのカールを最適化するように選択されるが、一般にはポリエチレン層の厚さは記録層側で１５〜５０μｍ、バック層側で１０〜４０μｍの範囲である。表裏のポリエチレンの比率は、記録層の種類や厚さ、中紙の厚み等により変化するカールを調整する様に設定されるのが好ましく、通常は表／裏のポリエチレンの比率は、厚みで概ね３／１〜１／３である。
【００９１】
更に、上記ポリエチレンで被覆紙支持体は、以下（１）〜（８）の特性を有していることが好ましい。
【００９２】
（１）引っ張り強さは、ＪＩＳ Ｐ ８１１３で規定される強度で縦方向が１９．６〜２９４Ｎ、横方向が９．８〜１９６Ｎであることが好ましい。
【００９３】
（２）引き裂き強度は、ＪＩＳ Ｐ ８１１６で規定される強度で縦方向が０．２０〜２．９４Ｎ、横方向が０．０９８〜２．４５Ｎが好ましい。
【００９４】
（３）圧縮弾性率は、９．８ｋＮ／ｃｍ^２が好ましい。
（４）不透明度は、ＪＩＳ Ｐ ８１３８に規定された方法で測定したときに８０％以上、特に８５〜９８％が好ましい。
【００９５】
（５）白さは、ＪＩＳ Ｚ ８７２７で規定されるＬ^＊、ａ^＊、ｂ^＊が、Ｌ^＊＝８０〜９６、ａ^＊＝−３〜＋５、ｂ^＊＝−７〜＋２であることが好ましい。
【００９６】
（６）クラーク剛直度は、記録媒体の搬送方向のクラーク剛直度が５０〜３００ｃｍ３／１００である支持体が好ましい。
【００９７】
（７）原紙中の水分は、中紙に対して４〜１０％が好ましい。
（８）記録層を設ける面側の光沢度（７５度鏡面光沢度）は、１０〜９０％が好ましい。
【００９８】
次いで、本発明に係る水性染料インクについて説明する。
本発明に係る水性染料インクは、少なくともイオン性（アニオン性、及びカチオン性の両方を意味する：以下、単にイオン性と記す）樹脂微粒子、水溶性染料、水及び有機溶媒を含有するものが好ましい。
【００９９】
本発明で用いることのできるイオン性樹脂微粒子を構成するポリマーとしては、特に制限はないが、例えば、アクリル系樹脂（例えば、アクリル樹脂、アクリル−スチレン共重合体、アクリル−酢酸ビニル共重合体、アクリル−シリコン共重合体等）、ウレタン樹脂、ポリエステル樹脂、酢酸ビニル系樹脂（例えば、酢酸ビニル樹脂、酢酸ビニル−エチレン共重合体等）、ブタジエン系樹脂（例えば、スチレン−ブタジエン共重合体、アクリルニトリル−ブタジエン共重合体等）、フッ素系樹脂、ポリアミド系樹脂等を挙げることができ、通常、これらの樹脂微粒子は、乳化重合法によって得られる。そこで用いられる界面活性剤、重合開始剤等については、常法で用いられるものを用いれば良い。樹脂微粒子の合成法に関しては、米国特許第２，８５２，３６８号、同２，８５３，４５７号、同３，４１１，９１１号、同３，４１１，９１２号、同４，１９７，１２７号、ベルギー特許第６８８，８８２号、同６９１，３６０号、同７１２，８２３号、特公昭４５−５３３１号、特開昭６０−１８５４０号、同５１−１３０２１７号、同５８−１３７８３１号、同５５−５０２４０号等に詳しく記載されている。
【０１００】
また、本発明に係るイオン性樹脂微粒子は、市販品としても容易に入手することができる。
【０１０１】
アニオン性ラテックスの例としてはＡＥ １２０（ＪＳＲ株式会社製）、スーパーフレックス４６０（第一工業製薬製）、スーパーフレックス３７０（第一工業製薬製）等があげられる。
【０１０２】
ノニオン性ラテックスの例としてはモビニール７３０（クラリアント社製）、スーパーフレックスＥ−４５００（第一工業製薬製）、スーパーフレックスＲ−５０００（第一工業製薬製）等があげられる。
【０１０３】
カチオン性ラテックスの例としてはスーパーフレックス６００（第一工業製薬製）、スーパーフレックス６１０（第一工業製薬製）、パテラコールＩＪ−６０（大日本インク製）等があげられる。但し、本発明は上記ラテックスに限定されるものではない。
【０１０４】
本発明においては、イオン性樹脂微粒子の平均粒径が、３０〜１００ｎｍが好ましく、最も好ましくは３０〜７０ｎｍである。
【０１０５】
イオン性樹脂微粒子の平均粒径は、光散乱方式やレーザードップラー方式を用いた市販の粒径測定装置、例えば、ゼータサイザー１０００（マルバーン社製）等を用いて、簡便に求めることができる。
【０１０６】
また、本発明に係る水溶性染料インクにおいては、イオン性樹脂微粒子のインク中での含有量が、０．２〜１０質量％であることが好ましく、さらに好ましくは０．５〜５質量％である。イオン性樹脂微粒子の添加量が０．２質量％以上であれば、ガス褪色性に対し、より十分な効果を発揮することができ、１０質量％以下であれば、インク吐出性がより安定となり、更に保存中でのインク粘度の上昇を抑制することができ、より好ましい。
【０１０７】
また、本発明においては、イオン性樹脂微粒子の最低造膜温度（ＭＦＴ）またはガラス転移温度（Ｔｇ）のいずれかが、６０℃以下であることが好ましい。本発明においては、イオン性樹脂微粒子の最低造膜温度をコントロールするため、造膜助剤を添加してもよい。造膜助剤は、可塑剤ともよばれポリマーラテックスの最低造膜温度を低下させる有機化合物（通常有機溶媒）であり、例えば「合成ラテックスの化学（室井宗一著、高分子刊行会発行（１９７０））」に記載されている。
【０１０８】
本発明に係る水溶性染料インクには、上記のイオン性樹脂微粒子の他に、少なくとも水溶性染料、水及び有機溶剤を含有している。
【０１０９】
本発明で用いることのできる水溶性染料としては、例えば、アゾ染料、メチン染料、アゾメチン染料、キサンテン染料、キノン染料、フタロシアニン染料、トリフェニルメタン染料、ジフェニルメタン染料等を挙げることができ、その具体的化合物を以下に示す。ただし、これら例示した化合物に限定されるものではない。
【０１１０】
〔Ｃ．Ｉ．アシッドイエロー〕
１、３、１１、１７、１８、１９、２３、２５、３６、３８、４０、４２、４４、４９、５９、６１、６５、６７、７２、７３、７９、９９、１０４、１１０、１１４、１１６、１１８、１２１、１２７、１２９、１３５、１３７、１４１、１４３、１５１、１５５、１５８、１５９、１６９、１７６、１８４、１９３、２００、２０４、２０７、２１５、２１９、２２０、２３０、２３２、２３５、２４１、２４２、２４６
〔Ｃ．Ｉ．アシッドオレンジ〕
３、７、８、１０、１９、２４、５１、５６、６７、７４、８０、８６、８７、８８、８９、９４、９５、１０７、１０８、１１６、１２２、１２７、１４０、１４２、１４４、１４９、１５２、１５６、１６２、１６６、１６８
〔Ｃ．Ｉ．アシッドレッド〕
１、６、８、９、１３、１８、２７、３５、３７、５２、５４、５７、７３、８２、８８、９７、１０６、１１１、１１４、１１８、１１９、１２７、１３１、１３８、１４３、１４５、１５１、１８３、１９５、１９８、２１１、２１５、２１７、２２５、２２６、２４９、２５１、２５４、２５６、２５７、２６０、２６１、２６５、２６６、２７４、２７６、２７７、２８９、２９６、２９９、３１５、３１８、３３６、３３７、３５７、３５９、３６１、３６２、３６４、３６６、３９９、４０７、４１５
〔Ｃ．Ｉ．アシッドバイオレット〕
１７、１９、２１、４２、４３、４７、４８、４９、５４、６６、７８、９０、９７、１０２、１０９、１２６
〔Ｃ．Ｉ．アシッドブルー〕
１、７、９、１５、２３、２５、４０、６２、７２、７４、８０、８３、９０、９２、１０３、１０４、１１２、１１３、１１４、１２０、１２７、１２８、１２９、１３８、１４０、１４２、１５６、１５８、１７１、１８２、１８５、１９３、１９９、２０１、２０３、２０４、２０５、２０７、２０９、２２０、２２１、２２４、２２５、２２９、２３０、２３９、２４９、２５８、２６０、２６４、２７８、２７９、２８０、２８４、２９０、２９６、２９８、３００、３１７、３２４、３３３、３３５、３３８、３４２、３５０
〔Ｃ．Ｉ．アシッドグリーン〕
９、１２、１６、１９、２０、２５、２７、２８、４０、４３、５６、７３、８１、８４、１０４、１０８、１０９
〔Ｃ．Ｉ．アシッドブラウン〕
２、４、１３、１４、１９、２８、４４、１２３、２２４、２２６、２２７、２４８、２８２、２８３、２８９、２９４、２９７、２９８、３０１、３５５、３５７、４１３
〔Ｃ．Ｉ．アシッドブラック〕
１、２、３、２４、２６、３１、５０、５２、５８、６０、６３、１０７、１０９、１１２、１１９、１３２、１４０、１５５、１７２、１８７、１８８、１９４、２０７、２２２
〔Ｃ．Ｉ．ダイレクトイエロー〕
８、９、１０、１１、１２、２２、２７、２８、３９、４４、５０、５８、８６、８７、９８、１０５、１０６、１３０、１３２、１３７、１４２、１４７、１５３
〔Ｃ．Ｉ．ダイレクトオレンジ〕
６、２６、２７、３４、３９、４０、４６、１０２、１０５、１０７、１１８
〔Ｃ．Ｉ．ダイレクトレッド〕
２、４、９、２３、２４、３１、５４、６２、６９、７９、８０、８１、８３、８４、８９、９５、２１２、２２４、２２５、２２６、２２７、２３９、２４２、２４３、２５４
〔Ｃ．Ｉ．ダイレクトバイオレット〕
９、３５、５１、６６、９４、９５
〔Ｃ．Ｉ．ダイレクトブルー〕
１、１５、７１、７６、７７、７８、８０、８６、８７、９０、９８、１０６、１０８、１６０、１６８、１８９、１９２、１９３、１９９、２００、２０１、２０２、２０３、２１８、２２５、２２９、２３７、２４４、２４８、２５１、２７０、２７３、２７４、２９０、２９１
〔Ｃ．Ｉ．ダイレクトグリーン〕
２６、２８、５９、８０、８５
〔Ｃ．Ｉ．ダイレクトブラウン〕
４４、１０６、１１５、１９５、２０９、２１０、２２２、２２３
〔Ｃ．Ｉ．ダイレクトブラック〕
１７、１９、２２、３２、５１、６２、１０８、１１２、１１３、１１７、１１８、１３２、１４６、１５４、１５９、１６９
〔Ｃ．Ｉ．ベイシックイエロー〕
１、２、１１、１３、１５、１９、２１、２８、２９、３２、３６、４０、４１、４５、５１、６３、６７、７０、７３、９１
〔Ｃ．Ｉ．ベイシックオレンジ〕
２、２１、２２
〔Ｃ．Ｉ．ベイシックレッド〕
１、２、１２、１３、１４、１５、１８、２３、２４、２７、２９、３５、３６、３９、４６、５１、５２、６９、７０、７３、８２、１０９
〔Ｃ．Ｉ．ベイシックバイオレット〕
１、３、７、１０、１１、１５、１６、２１、２７、３９
〔Ｃ．Ｉ．ベイシックブルー〕
１、３、７、９、２１、２２、２６、４１、４５、４７、５２、５４、６５、６９、７５、７７、９２、１００、１０５、１１７、１２４、１２９、１４７、１５１
〔Ｃ．Ｉ．ベイシックグリーン〕
１、４
〔Ｃ．Ｉ．ベイシックブラウン〕
１
〔Ｃ．Ｉ．リアクティブイエロー〕
２、３、７、１５、１７、１８、２２、２３、２４、２５、２７、３７、３９、４２、５７、６９、７６、８１、８４、８５、８６、８７、９２、９５、１０２、１０５、１１１、１２５、１３５、１３６、１３７、１４２、１４３、１４５、１５１、１６０、１６１、１６５、１６７、１６８、１７５、１７６
〔Ｃ．Ｉ．リアクティブオレンジ〕
１、４、５、７、１１、１２、１３、１５、１６、２０、３０、３５、５６、６４、６７、６９、７０、７２、７４、８２、８４、８６、８７、９１、９２、９３、９５、１０７
〔Ｃ．Ｉ．リアクティブレッド〕
２、３、５、８、１１、２１、２２、２３、２４、２８、２９、３１、３３、３５、４３、４５、４９、５５、５６、５８、６５、６６、７８、８３、８４、１０６、１１１、１１２、１１３、１１４、１１６、１２０、１２３、１２４、１２８、１３０、１３６、１４１、１４７、１５８、１５９、１７１、１７４、１８０、１８３、１８４、１８７、１９０、１９３、１９４、１９５、１９８、２１８、２２０、２２２、２２３、２２８、２３５
〔Ｃ．Ｉ．リアクティブバイオレット〕
１、２、４、５、６、２２、２３、３３、３６、３８
〔Ｃ．Ｉ．リアクティブブルー〕
２、３、４、５、７、１３、１４、１５、１９、２１、２５、２７、２８、２９、３８、３９、４１、４９、５０、５２、６３、６９、７１、７２、７７、７９、８９、１０４、１０９、１１２、１１３、１１４、１１６、１１９、１２０、１２２、１３７、１４０、１４３、１４７、１６０、１６１、１６２、１６３、１６８、１７１、１７６、１８２、１８４、１９１、１９４、１９５、１９８、２０３、２０４、２０７、２０９、２１１、２１４、２２０、２２１、２２２、２３１、２３５、２３６
〔Ｃ．Ｉ．リアクティブグリーン〕
８、１２、１５、１９、２１
〔Ｃ．Ｉ．リアクティブブラウン〕
２、７、９、１０、１１、１７、１８、１９、２１、２３、３１、３７、４３、４６
〔Ｃ．Ｉ．リアクティブブラック〕
５、８、１３、１４、３１、３４、３９
等が挙げられ、これら上記に列挙した染料は、「染色ノート第２１版」（出版；色染社）等に記載されている。
【０１１１】
本発明で用いることのできる有機溶媒は、特に制限はないが、水溶性の有機溶媒が好ましく、具体的にはアルコール類（例えば、メタノール、エタノール、プロパノール、イソプロパノール、ブタノール、イソブタノール、セカンダリーブタノール、ターシャリーブタノール、ペンタノール、ヘキサノール、シクロヘキサノール、ベンジルアルコール等）、多価アルコール類（例えば、エチレングリコール、ジエチレングリコール、トリエチレングリコール、ポリエチレングリコール、プロピレングリコール、ジプロピレングリコール、ポリプロピレングリコール、ブチレングリコール、ヘキサンジオール、ペンタンジオール、グリセリン、ヘキサントリオール、チオジグリコール等）、多価アルコールエーテル類（例えば、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノブチルエーテル、エチレングリコールモノフェニルエーテル、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテル、ジエチレングリコールジメチルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノブチルエーテル、エチレングリコールモノメチルエーテルアセテート、トリエチレングリコールモノメチルエーテル、トリエチレングリコールモノエチルエーテル、トリエチレングリコールモノブチルエーテル、トリエチレングリコールジメチルエーテル、ジプロピレングリコールモノプロピルエーテル、トリプロピレングリコールジメチルエーテル等）、アミン類（例えば、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、Ｎ−メチルジエタノールアミン、Ｎ−エチルジエタノールアミン、モルホリン、Ｎ−エチルモルホリン、エチレンジアミン、ジエチレンジアミン、トリエチレンテトラミン、テトラエチレンペンタミン、ポリエチレンイミン、ペンタメチルジエチレントリアミン、テトラメチルプロピレンジアミン等）、アミド類（例えば、ホルムアミド、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド等）、複素環類（例えば、２−ピロリドン、Ｎ−メチル−２−ピロリドン、Ｎ−シクロヘキシル−２−ピロリドン、２−オキサゾリドン、１，３−ジメチル−２−イミダゾリジノン等）、スルホキシド類（例えば、ジメチルスルホキシド等）、スルホン類（例えば、スルホラン等）、スルホン酸塩類（例えば１−ブタンスルホン酸ナトリウム塩等）、尿素、アセトニトリル、アセトン等が挙げられる。
【０１１２】
本発明に係る水溶性染料インクにおいて、各種の界面活性剤を用いることができる。本発明で用いることのできる各界面活性剤として、特に制限はないが、例えば、ジアルキルスルホコハク酸塩類、アルキルナフタレンスルホン酸塩類、脂肪酸塩類等のアニオン性界面活性剤、ポリオキシエチレンアルキルエーテル類、ポリオキシエチレンアルキルアリルエーテル類、アセチレングリコール類、ポリオキシエチレン・ポリオキシプロピレンブロックコポリマー類等のノニオン性界面活性剤、アルキルアミン塩類、第四級アンモニウム塩類等のカチオン性界面活性剤が挙げられる。特に樹脂微粒子とおなじ極性のアニオン、またはカチオン界面活性剤およびノニオン性界面活性剤を好ましく用いることができる。
【０１１３】
また、本発明におけるインク中に、高分子界面活性剤も用いることができ、例えば、スチレン−アクリル酸−アクリル酸アルキルエステル共重合体、スチレン−アクリル酸共重合体、スチレン−マレイン酸−アクリル酸アルキルエステル共重合体、スチレン−マレイン酸共重合体、スチレン−メタクリル酸−アクリル酸アルキルエステル共重合体、スチレン−メタクリル酸共重合体、スチレン−マレイン酸ハーフエステル共重合体、ビニルナフタレン−アクリル酸共重合体、ビニルナフタレン−マレイン酸共重合体等を挙げることができる。
【０１１４】
本発明に係る水溶性染料インクでは、上記説明した以外に、必要に応じて、出射安定性、プリントヘッドやインクカートリッジ適合性、保存安定性、画像保存性、その他の諸性能向上の目的に応じて、公知の各種添加剤、例えば、粘度調整剤、比抵抗調整剤、皮膜形成剤、紫外線吸収剤、酸化防止剤、退色防止剤、防ばい剤、防錆剤等を適宜選択して用いることができ、例えば、流動パラフィン、ジオクチルフタレート、トリクレジルホスフェート、シリコンオイル等の油滴微粒子、特開昭５７−７４１９３号、同５７−８７９８８号及び同６２−２６１４７６号に記載の紫外線吸収剤、特開昭５７−７４１９２号、同５７−８７９８９号、同６０−７２７８５号、同６１−１４６５９１号、特開平１−９５０９１号及び同３−１３３７６号等に記載されている退色防止剤、特開昭５９−４２９９３号、同５９−５２６８９号、同６２−２８００６９号、同６１−２４２８７１号および特開平４−２１９２６６号等に記載されている蛍光増白剤等を挙げることができる。
【０１１５】
本発明のインクジェット記録方法で使用するインクジェットヘッドは、オンデマンド方式でもコンティニュアス方式でも構わない。また吐出方式としては、電気−機械変換方式（例えば、シングルキャビティー型、ダブルキャビティー型、ベンダー型、ピストン型、シェアーモード型、シェアードウォール型等）、電気−熱変換方式（例えば、サーマルインクジェット型、バブルジェット（Ｒ）型等）、静電吸引方式（例えば、電界制御型、スリットジェット型等）及び放電方式（例えば、スパークジェット型等）などを具体的な例として挙げることができるが、いずれの吐出方式を用いても構わない。
【０１１６】
【実施例】
以下、本発明を実施例により具体的に説明するが、本発明はこれに限定されるものではない。
【０１１７】
実施例１
《記録媒体の作製》
（シリカ分散液Ｄ１の調製）
予め均一に分散されている１次粒子の平均粒径が約０．０４０μｍの気相法シリカ（日本アエロジル社製：アエロジル５０）を２５質量％、水溶性蛍光増白剤ＵＶＩＴＥＸＮＦＷ ＬＩＱＵＩＤ（チバスペシャリティーケミカルズ社製）を０．３質量％含むシリカ分散液Ｂ１（ｐＨ＝２．３、エタノール１質量％含有）の４００Ｌを、カチオン性ポリマー（Ｐ−１）を１２質量％、ｎ−プロパノールを１０質量％およびエタノールを２質量％含有する水溶液Ｃ１（ｐＨ＝２．５、サンノブコ社製の消泡剤ＳＮ３８１を２ｇ含有）の１１０Ｌに、室温で３０００ｒｐｍで攪拌しながら添加した。次いで、ホウ酸とほう砂の１：１質量比の混合水溶液Ａ１（各々３質量％の濃度）の５４Ｌを攪拌しながら徐々に添加した。
【０１１８】
次いで、三和工業株式会社製の高圧ホモジナイザーで、３ｋＮ／ｃｍ^２の圧力で分散し、全量を純水で６３０Ｌに仕上げて、ほぼ透明なシリカ分散液Ｄ１を得た。
【０１１９】
上記シリカ分散液Ｄ１を、３０μｍの濾過精度を有するアドバンテック東洋社製のＴＣＰ−３０タイプのフィルターを用いて濾過を行った。
【０１２０】
（シリカ分散液Ｄ２の調製）
上記シリカ分散液Ｄ１の調製において、上記シリカ分散液Ｂ１の４００Ｌを、カチオン性ポリマー（Ｐ−２）を１２質量％、ｎ−プロパノール１０質量％およびエタノールを２質量％含有する水溶液Ｃ２（ｐＨ＝２．５）の１２０Ｌに、室温で３０００ｒｐｍで攪拌しながら添加し、次いで、上記混合水溶液Ａ１の５２Ｌを攪拌しながら徐々に添加した以外は同様にしてシリカ分散液Ｄ２を調製した。
【０１２１】
（シリカ分散液Ｄ３の調製）
上記シリカ分散液Ｄ２の調製において、水溶液Ｃ２の替わりに、ｎ−プロパノール１０質量％およびエタノールを２質量％含有する水溶液Ｃ３を１２０Ｌ添加した以外は同様にしてシリカ分散液Ｄ３を調製した。
【０１２２】
（シリカ分散液Ｄ４の調製）
上記シリカ分散液Ｄ１の調製において、カチオン性ポリマー（Ｐ−１）の替わりに、アニオン性ポリマー（Ｐ−Ａ）（ポリビニルスルホン酸 重合度２０００）を用いたこと以外は同様にしてシリカ分散液Ｄ４を調製した。
【０１２３】
（オイル分散液の調製）
ジイソデシルフタレート２０ｋｇと酸化防止剤（ＡＯ−１）２０ｋｇとを４５ｋｇの酢酸エチルに加熱溶解し、酸処理ゼラチン８ｋｇ、カチオン性ポリマーＰ−１を２．９ｋｇおよびサポニン１０．５ｋｇとを含有するゼラチン水溶液２１０Ｌと５５℃で混合し、高圧ホモジナイザーで乳化分散した後、全量を純水で３００Ｌに仕上げて、オイル分散液を調製した。
【０１２４】
【化６】

【０１２５】
（塗布液の調製）
上記調製した各分散液を使用して、以下に記載の各添加剤を順次混合して、塗布液を調製した。なお、各添加量は塗布液１Ｌ当たりの量で表示した。
【０１２６】

純水で全量を１０００ｍｌに仕上げた
なお、最外層におけるカチオン性ポリマー（Ｐ−２）と無機顔料微粒子（アエロジル５０）との質量比は、１：６．９である。
【０１２７】
【化７】

【０１２８】
上記の様にして調製した各塗布液を、２０μｍの濾過精度を持つアドバンテック東洋社製のＴＣＰＤ−３０フィルターで濾過した後、ＴＣＰＤ−１０フィルターで濾過した。
【０１２９】
（塗布）
次に、上記の各塗布液を下記に記載の湿潤膜厚となるよう、４０℃で両面にポリエチレンを被覆した紙支持体１上に、スライドホッパー型コーターを用いて４層同時塗布した。
【０１３０】
〈湿潤膜厚〉
第１層：４２μｍ
第２層：３９μｍ
第３層：４４μｍ
最外層：４μｍ
なお、上記で使用した紙支持体１は、含水率が８％で、坪量が１７０ｇの写真用原紙表面を、アナターゼ型酸化チタンを６％含有するポリエチレンを厚さ３５μｍで押し出し溶融塗布し、裏面には厚さ４０μｍのポリエチレンを押し出し溶融塗布した。表面側は、コロナ放電した後、ポリビニルアルコール（クラレ社製ＰＶＡ２３５）を記録媒体１ｍ^２当たり０．０５ｇになるように下引き層を塗布し、裏面側にはコロナ放電加工した後、Ｔｇが約８０℃のスチレン・アクリル酸エステル系ラテックスバインダー約０．４ｇ、帯電防止剤（カチオン性ポリマー）０．１ｇおよび約２μｍのシリカ０．１ｇをマット剤として含有するバック層を塗布した。
【０１３１】
なお、記録層用塗布液の塗布を行った後の乾燥は、５℃に保った冷却ゾーンを１５秒間通過させて膜面の温度を１３℃にまで低下させた後、複数設けた乾燥ゾーンの温度を適宜設定して乾燥を行った後、ロール状に巻き取って記録媒体１を得た。
【０１３２】
〔記録媒体２の作製〕
上記記録媒体１の作製において、最外層で用いたカチオン性ポリマー（Ｐ−２）を、シリカ分散液Ｄ３を用いることで除いた以外は同様にして、記録媒体２を作製した。
【０１３３】
〔記録媒体３の作製〕
上記記録媒体１の作製において、第１及び第２層で用いたカチオン性ポリマー（Ｐ−１）と第３及び最外層で用いたカチオン性ポリマー（Ｐ−２）を、シリカ分散液Ｄ３を用いることで除いた以外は同様にして、記録媒体３を作製した。
【０１３４】
〔記録媒体４の作製〕
上記記録媒体１の作製において、第１及び第２層で用いたカチオン性ポリマー（Ｐ−１）と第３及び最外層で用いたカチオン性ポリマー（Ｐ−２）を、シリカ分散液Ｄ４を用いることでアニオン性ポリマー（Ｐ−Ａ）にした以外は同様にして、記録媒体４を作製した。
【０１３５】
〔記録媒体５の作製〕
上記記録媒体４の作製において、最外層で用いたアニオン性ポリマー（Ｐ−Ａ）を、シリカ分散液Ｄ３を用いることで除いた以外は同様にして、記録媒体５を作製した。
【０１３６】
《水性染料インクの調製》
〔染料インク１の調製〕
アニオン染料 Ｃ．Ｉ．Ｄｉｒｅｃｔ Ｂｌａｃｋ １０８ ５質量％
アニオン性ラテックス ＡＥ１２０（ＪＳＲ株式会社製） ２質量％
ジエチレングリコール ２５質量％
ジオクチルスルホコハク酸ナトリウム ０．０１質量％
水で全量を１００質量％に仕上げて、染料インク１を調製した。
【０１３７】
〔染料インク２〜６の調製〕
上記染料インク１のアニオン性ラテックス ＡＥ１２０の替わりに、表１に記載の各樹脂微粒子（ラテックス）を添加した以外は同様にして、染料インク２〜６を調製した。
【０１３８】
〔染料インク７〜９の調製〕
上記染料インク１において、アニオン染料をカチオン染料Ｃ．Ｉ．ＢａｓｉｃＢｌｕｅ １９９に替え、アニオン性ラテックス ＡＥ１２０の替わりに、表１に記載の各樹脂微粒子（ラテックス）を添加した以外は同様にして、染料インク７〜９を調製した。
【０１３９】
〔染料インク１０の調製〕
上記染料インク１において、アニオン性ラテックス ＡＥ１２０を除いた以外は同様にして、染料インク１０を調製した。
【０１４０】
なお、各樹脂微粒子（ラテックス）の平均粒径は、レーザードップラー方式のゼータサイザー１０００（マルバーン社製）を用いて測定した。
【０１４１】
【表１】

【０１４２】
《インクジェット画像形成》
プリンターとして、セイコーエプソン社製のＭＪ８００Ｃを用い、プリンターに装備されているインクカートリッジに、上記調製した染料インク１〜１０をそれぞれ装填し、表２に記載の各記録媒体との組み合わせにより、吐出量として１０ｍｌ／ｍ^２となるようにベタ画像を印字し、画像１〜２５を出力した。
【０１４３】
また、インクセットを６０℃のオーブンで ７２時間静置保存し、同様にベタ画像を印字した。
【０１４４】
《インクジェット画像の測定及び評価》
以上の様にして形成したシアン画像について、下記の方法に従って各測定及び評価を行った。
【０１４５】
（ガス褪色耐性の評価）
各ベタ画像を、２３℃でオゾン濃度が５０ｐｐｍの環境下に１２０分間曝露させた後、曝露前後の反射濃度を光学濃度計（Ｘ−Ｒｉｔｅ社製Ｘ−Ｒｉｔｅ９３８）の赤色単色光で測定し、下式に従い画像残存率を求め、下記の基準に則りガス褪色耐性の評価を行った。
【０１４６】
画像残存率＝曝露後の濃度／曝露前の濃度×１００（％）
５：画像残存率が９５％以上
４：画像残存率が８５〜９５％未満
３：画像残存率が７０〜８５％未満
２：画像残存率が６０〜７０％未満
１：画像残存率が６０％未満。
【０１４７】
（光沢性（Ｃ値）の評価）
上記作成したベタ画像を、写像性測定器ＩＣＭ−１ＤＰ（スガ試験機械社製）で反射６０度、光学くし２ｍｍでの写像性（光沢値Ｃ値％）を測定した。Ｃ値は実用上７０以上が好ましく、８０以上がより好ましく、８５以上が特に好ましく、７０未満は実用性が乏しい。
【０１４８】
（発色性の評価）
上記作成したベタ画像の反射濃度を、光学濃度計（Ｘ−Ｒｉｔｅ社製Ｘ−Ｒｉｔｅ９３８）の赤色単色光で測定し、下記に従い発色性の評価を行った。
○：画像番号２５に対して０．９５〜１．０倍の濃度を示す
△：画像番号２５に対して０．９４倍以下の濃度を示す
【０１４９】
【表２】

【０１５０】
表２より明らかなように、樹脂粒子を含むインクで作製した画像はガス褪色耐性が優れていた。
【０１５１】
また、イオン性媒染剤を最上層に含有しない記録媒体を用いることで、高い写像性を得られることがわかった。
【０１５２】
また、樹脂粒子がイオン性を持つことで、インク保存後もプリントで得られるＣ値が高いままであることがわかった。
【０１５３】
また、記録媒体中にイオン性媒染剤を含有した方が、発色性の点でより望ましいことがわかった。
【０１５４】
実施例２
〔記録媒体６〜１７の作製〕
上記記録媒体２の作製において、最外層で用いた無機顔料粒子（気相法シリカ）の粒径を表３記載の様に変更した以外は同様にして記録媒体６〜１７をそれぞれ作製した。
【０１５５】
〔染料インク１１〜２２の調製〕
上記染料インク１のアニオン性ラテックス ＡＥ１２０の粒径を、表３に記載の粒径に変更した以外は同様にして、染料インク１１〜２２を調製した。
【０１５６】
〔画像２６〜５０の作製〕
実施例１に記載の方法と同様にして、表３に記載の記録媒体とインクの組み合わせを行い、画像を作成した。
【０１５７】
（光沢発色の評価）
上記作成したベタ画像に入射角６０℃で白色光をあて、直接反射光の色味を目視評価した。
赤色：反射光が赤く色づいている
黄色：反射光が黄色く色づいている
青色；反射光が青く色づいている
白色：色が付いていない
光沢性の評価は、実施例１と同様に行い、結果を表３に示す。
【０１５８】
【表３】

【０１５９】
表３より明らかなように、記録材料の無機顔料粒子の１次粒径が３０ｎｍ以上であれば反射光に色味がつかないため好ましく、１次粒径が１００ｎｍ以下であればＣ値８０以上が得られるため好ましい。
【０１６０】
また、インク中の樹脂粒径が３０ｎｍ以上であれば反射光に色味がつかないため好ましく、１００ｎｍ以下であればＣ値８０以上が得られるため好ましい。
【０１６１】
実施例３
〔記録媒体１８〜２７の作製〕
上記記録媒体２の作製において、最外層の膜厚を表３記載の様に変更した以外は同様にして記録媒体１８〜２７をそれぞれ作製した。
【０１６２】
〔画像５１〜６１の作製〕
実施例１に記載の方法と同様にして、表４に記載の記録媒体とインクの組み合わせを行い、画像を作成した。
【０１６３】
（ビーディングの評価）
上記作製したベタ画像の表面を目視観察し、インク吸収速度が遅く、インク液滴が記録材料上で混ざってしまうビーディング現象の有無を評価した。
○：全く見られない
△：一部に見られる
×：プリント全面に見られる
光沢性の評価は、実施例１と同様に行い、結果を表４に示す。
【０１６４】
【表４】

【０１６５】
表４より明らかなように、最外層膜厚が０．１μｍ以上であればインク打ち込み時のメディア菱面でのラテックス粒子の凝集が抑制され、高光沢が得られる。最外層膜厚が１０μｍ以下であればビーディングがほとんど目立たなくなる。
【０１６６】
【発明の効果】
本発明により、ガス褪色耐性、光沢性、光沢反射光の色味、及び画像のビーディング耐性に優れたインクジェット記録方法を提供することができた。
【図面の簡単な説明】
【図１】従来のインクジェット記録媒体の記録時の模式図である。
【図２】本発明に係るインクジェット記録媒体の記録時の模式図である。
【符号の説明】
１ 支持体
２ インク吸収層
３ 最外層
４ カチオン性媒染剤
５ インク液滴[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel ink jet recording method, and more particularly to an ink jet recording method excellent in gas fading resistance, glossiness, color developability, ink absorption speed during printing, and ink preservability before printing.
[0002]
[Prior art]
Ink-jet recording is a method in which micro droplets of ink are ejected according to various operating principles and deposited on a recording sheet such as paper to record images and characters. Has advantages such as being easy.
[0003]
In particular, since the image quality of printers has recently improved and has reached photographic quality, the recording paper also realizes photographic quality and reproduces the texture (glossiness, smoothness, stiffness, etc.) of silver halide photography. Is required.
[0004]
As one method for reproducing the texture of a silver salt photograph, a so-called swelling type in which a hydrophilic binder such as gelatin or polyvinyl alcohol is coated on a support as a recording paper is known. However, this method has drawbacks such as a slow ink absorption rate, a sticky surface after printing, and an image that tends to bleed due to the influence of humidity during storage. In particular, since the ink absorption speed is slow, the ink droplets mix before being absorbed, tend to cause bleeding (bleeding) between different colors and uneven color (beading) within the same color, Achievement is very difficult.
[0005]
As a method for solving the above problems, a so-called void type is becoming the mainstream instead of the above-described swelling type, and is characterized by a high absorption speed because ink is absorbed into fine voids. However, when a void-type inkjet recording medium (hereinafter also simply referred to as a recording medium) capable of achieving high image quality and a water-soluble dye ink are combined, image discoloration caused by gas in the storage environment is a significant problem. It has become. Although the details of the mechanism of image fading caused by this gas have not yet been clarified, the gas in the storage environment, particularly the oxidizing gas, easily penetrates into the recording medium through the void structure. It is presumed that image discoloration proceeds by reaching and decomposing dye molecules.
[0006]
As a method of preventing fading caused by such oxidizing gas, after printing an image on a recording medium, the surface is laminated or the recording medium on which the image is printed is stored in a gas-blockable frame. However, both methods require post-processing, which complicates the processing steps, and results in an increase in cost due to the preparation of equipment for that purpose.
[0007]
As a means of overcoming such drawbacks, by printing a water-soluble dye ink containing resin fine particles in advance on a recording medium, the resin fine particles remain on the surface of the recording medium, and then formed into a film, There has been proposed a method for preventing penetration of an oxidizing gas into a recording medium by forming a blocking layer (see, for example, Patent Documents 1 to 5).
[0008]
However, in the above configuration, the electrical properties of the resin fine particles in the ink and the mordant in the recording material have a great influence on the film formability of the resin fine particles.
[0009]
Usually, in a recording medium, a cationic mordant is used for an ink containing an anionic dye and an ink containing a cationic dye for the purpose of fixing the dye component of the ink applied from the nozzle in the layer. In some cases, an anionic mordant is contained in the recording layer.
[0010]
On the other hand, when the resin fine particles are added to the ink, it is necessary to select anionic or nonionic resin fine particles for the anionic dye ink and cationic or nonionic resin fine particles for the cationic dye ink. Otherwise, the resin fine particles are electrically neutralized in the ink, disperse the power, and aggregate.
[0011]
On the other hand, when an ink containing an anionic dye and anionic resin fine particles is applied to a recording material having a cationic mordant on the surface layer, the anionic fine particles aggregate on the surface of the recording medium, resulting in unevenness in the printed portion. The surface smoothness inherent to the recording material is impaired, and the image clarity is lowered as shown in FIG.
[0012]
FIG. 1 is a schematic diagram during recording on a conventional ink jet recording medium. A cationic mordant 4 is contained in the ink absorbing layer 2 on the support 1 and in the outermost layer 3 which is located farthest from the support 1. When recording with ink droplets 5 containing anionic resin fine particles on such an ink jet recording medium, as shown in FIG. 1, the latex particles in the ink droplets 5 do not penetrate into the recording layer, and the printed portion is uneven. Arise.
[0013]
Similarly, when an ink containing a cationic dye and cationic resin fine particles is applied to a recording material having an anionic mordant on the surface layer, the cationic fine particles are likely to be aggregated on the surface of the recording medium, and as a result, the printed portion is printed. Unevenness occurs, and the surface smoothness inherent in the recording material is impaired, resulting in a decrease in image clarity.
[0014]
On the other hand, nonionic resin fine particles exhibit hydrophilicity by hydration of water molecules to ether oxygen of ethylene oxide chain, but this hydration due to hydrogen bonds weakens as the temperature rises and exceeds a certain temperature. In this case, the dispersion force is rapidly reduced and aggregation occurs. For this reason, from the viewpoint of ink storage stability, the application of nonionic resin fine particles remains a problem in terms of temperature control during ink transportation and storage, and associated cost increases.
[0015]
[Patent Document 1]
JP-A-55-18412 (Claims, page 1)
[0016]
[Patent Document 2]
JP-A-3-6270 (Claims, pages 2-3)
[0017]
[Patent Document 3]
Japanese Patent Laid-Open No. 3-160068 (Claims, page 3)
[0018]
[Patent Document 4]
JP-A-3-163175 (Claims, page 2)
[0019]
[Patent Document 5]
JP 2001-187852 A (Claims, pages 2 to 3)
[0020]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and its purpose is that the resulting print has high image quality, excellent gas fading resistance, and glossiness, and further excellent color development, gloss discoloration suppression, and beading suppression. To provide an ink jet recording method which is excellent in storability as an ink, easy to handle and relatively low cost.
[0021]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitutions.
[0022]
1. An ink jet recording method comprising recording an image by ejecting an aqueous dye ink containing ionic resin fine particles onto an ink jet recording medium having a recording layer containing no ionic mordant.
[0023]
2. An ink jet recording medium has a plurality of recording layers, and only an outermost layer on the recording surface side contains an ionic resin particle, and an aqueous dye ink containing ionic resin fine particles is ejected to record an image. An inkjet recording method characterized by the above.
[0024]
3. 3. The ink jet recording method according to 1 or 2, wherein the recording layer of the ink jet recording medium is a void type.
[0025]
4). 4. The inkjet recording method according to any one of 1 to 3, wherein the inkjet recording medium contains fine particles in an outermost layer on the recording surface side, and the primary particle size of the fine particles is 30 to 100 nm. .
[0026]
5. 5. The ink jet recording method according to any one of 1 to 4, wherein the particle diameter of the ionic resin fine particles contained in the aqueous dye ink is 30 to 100 nm.
[0027]
6). 6. The ink jet recording method according to any one of 1 to 5, wherein the outermost layer on the recording surface side of the ink jet recording medium has a thickness of 100 nm to 10 μm.
[0028]
The present invention will be described in more detail. As a result of intensive studies in view of the above problems, the present inventors have recorded a gas by discharging an aqueous dye ink containing ionic resin fine particles onto an inkjet recording medium containing no ionic mordant, thereby recording a gas. It has been found that an ink jet recording method using a dye ink excellent in fading resistance, glossiness and bleeding resistance can be realized, and as soon as the present invention has been achieved.
[0029]
That is, by discharging an aqueous dye ink containing ionic resin fine particles onto an ink jet recording medium that does not contain an ionic mordant and recording an image, aggregation of the resin fine particles on the surface of the printed part is suppressed, and gas fading resistance It is possible to form an image excellent in bleeding resistance, glossiness and color development.
[0030]
First, the ink jet recording medium according to the present invention will be described.
FIG. 2 is a schematic diagram at the time of recording on the ink jet recording medium according to the present invention. As shown in FIG. 2, the support 1 has at least two recording layers, the outermost layer 3 located farthest from the support 1 contains inorganic pigment particles, and contains an ionic mordant. One of the features is that the ink absorbing layer 2 located in the lowermost layer of the outermost layer has a void structure containing inorganic pigment fine particles and an ionic mordant.
[0031]
Examples of inorganic pigment fine particles that can be used in the recording layer according to the present invention include, for example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, water Zinc oxide, zinc sulfide, zinc carbonate, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, And white inorganic pigments such as magnesium hydroxide.
[0032]
The average particle size of the inorganic pigment fine particles is obtained by observing the particles themselves or the particles appearing on the cross section or surface of the surface layer with an electron microscope, obtaining the particle size of 1,000 arbitrary particles, and calculating the simple average value (number average). As required. Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.
[0033]
As the inorganic pigment fine particles, it is preferable to use solid fine particles selected from silica and alumina or alumina hydrate.
[0034]
As the silica, silica synthesized by a usual wet method, colloidal silica, silica synthesized by a gas phase method, or the like is preferably used, and the fine particle silica particularly preferably used in the present invention is a colloidal silica or a gas phase method. Synthesized fine particle silica, colloidal silica has excellent particle performance, and fine particle silica synthesized by a vapor phase method has high performance. Alumina or alumina hydrate may be crystalline or amorphous, and any shape such as amorphous particles, spherical particles, and acicular particles can be used.
[0035]
The inorganic pigment fine particles constituting the outermost layer on the recording surface side preferably have a particle size of 100 nm or less. For example, in the case of the vapor phase fine particle silica, the average particle size (particle size in the dispersion state before coating) of the primary particles of the inorganic pigment fine particles dispersed in the primary particle state is preferably 30 to 100 nm. is there. When the average particle size of the primary particles of the inorganic pigment fine particles is less than 30 nm, the reflected light becomes tinted, and when it exceeds 100 nm, the gloss value becomes low.
[0036]
The thickness of the outermost layer on the recording surface side is preferably 100 nm to 10 μm. When the thickness is less than 100 nm, the gloss value is low, and when it exceeds 10 μm, beading becomes conspicuous.
[0037]
The inorganic pigment fine particles constituting the recording layer other than the outermost layer are preferably silica synthesized by a gas phase method having an average particle diameter of 4 to 20 nm. For example, Aerosil manufactured by Nippon Aerosil Co., Ltd. is commercially available. Yes. The vapor phase fine particle silica can be dispersed to primary particles relatively easily by sucking and dispersing in water using, for example, a jet stream inductor mixer manufactured by Mitamura Riken Kogyo Co., Ltd.
[0038]
Next, the anionic polymer will be described. A polymer having a sulfonic acid group, a carboxyl group, and a phosphoric acid group is preferable as the anionic polymer, and an anionic polymer having a sulfonic acid group is particularly preferable. Examples of preferred anionic polymers include sulfonic acid group types such as homopolymers of vinyl sulfonic acid, vinyl sulfonic acids such as vinyl chloride, acrylonitrile, styrene, vinyl acetate and other polymerizable monoolefinic compounds. And copolymers with one or more of such copolymerizable organic monomers. As the type of carboxyl group, acrylic acid or methacrylic acid derivatives such as acrylic acid, alkali metal and ammonium salts of acrylic acid, methacrylic acid, alkali metal salts of methacrylic acid, acrylamide, methacrylamide, N-alkyl substituted amide, N -Crosslinked anionic polymers of aminoalkylamides and corresponding N-alkylaminoalkyl substituted amides, aminoalkyl acrylates, aminoalkyl methacrylamides and N-alkyl substituted aminoalkyl esters of acrylic acid or methacrylic acid. These polymeric compositions may be homopolymers and may be ethylene, propylene, isobutylene, styrene, α-methylstyrene, vinyl acetate, vinyl formate, alkyl ether, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride. And copolymers with other copolymerizable monomers such as alkyl acrylate, alkyl methacrylate, alkyl maleate, alkyl fumarate, and other copolymerizable olefinic monomers. .
[0039]
Next, the cationic polymer will be described. There is no restriction | limiting in particular as a cationic polymer used for this invention, A conventionally well-known cationic polymer is mentioned by an inkjet recording paper, For example, "Inkjet printer technology and material" 268 pages (CMC publication 1998), The polymers described in JP-A-9-193532 and the like can be mentioned. Among them, cationic polymers having a quaternary ammonium base are preferable. For example, a cationic polymer having a guanidyl group described in JP-A-57-64591, dimethyldiallylammonium chloride described in JP-A-59-20696, polyamine sulfones described in JP-A-59-33176, (Meth) acrylic acid alkyl quaternary ammonium salt or (meth) acrylamide alkyl quaternary ammonium salt type cationic polymer disclosed in JP-A-63-115780, JP-A-64-9776 and JP-A-64-75281 Copolymer of dimethylallylammonium chloride and acrylamide, a cationic polymer containing two or more quaternary nitrogen atoms in the repeating unit described in JP-A-3-133686, and a fourth polymer described in JP-A-4-288283 Polyvinylpyrrolidone with secondary ammonium base Cationic polymers obtained by reaction of secondary amines and epihalohydrins described in JP-A-6-92010 and JP-A-6-234268, polystyrene-type cationic polymers described in International Patent Publication No. 99-64248, JP-A-11- Examples thereof include a cationic polymer composed of a repeating unit having two or more kinds of cationic groups described in No. 348409.
[0040]
The cationic polymer particularly preferred in the present invention is a cationic polymer having a quaternary ammonium base, more preferably a cationic polymer having a quaternary ammonium base in the side chain, particularly preferably the following general formula (1) A cationic polymer having a repeating unit represented by the formula:
[0041]
[Chemical 1]

[0042]
In the general formula (1), R represents a hydrogen atom or an alkyl group, and R ₁ , R ₂ , R ₃ Each represents an alkyl group or a benzyl group, and J represents a simple bond or a divalent organic group. X ⁻ Represents an anionic group.
[0043]
In the general formula (1), the alkyl group represented by R is preferably a methyl group. R ₁ , R ₂ And R ₃ The alkyl group represented by is preferably a methyl group, an ethyl group or a benzyl group. The divalent organic group represented by J is preferably —CON (R ′) —. R ′ represents a hydrogen atom or an alkyl group.
[0044]
Examples of the anion group represented by X include halogen ions, acetate ions, methyl sulfate ions, p-toluenesulfonate, and the like.
[0045]
A preferred cationic polymer may be a homopolymer composed of the repeating unit represented by the general formula (1), or may be copolymerized with another copolymerizable monomer. Examples of the copolymerizable repeating unit include cationic monomers other than the general formula (1) and monomers having no cationic group.
[0046]
As a monomer which has a cationic group, the following repeating unit can be mentioned, for example.
[0047]
[Chemical 2]

[0048]
Examples of the copolymerizable repeating unit having no cationic group include, for example, ethylene, styrene, butadiene, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, Examples include octyl acrylate, hydroxyl ethyl methacrylate, acrylamide, vinyl acetate, vinyl methyl ether, vinyl chloride, 4-vinyl pyridine, N-vinyl pyrrolidone, N-vinyl imidazole, and acrylonitrile.
[0049]
When the cationic polymer preferably used in the present invention has a repeating unit represented by the general formula (1), the repeating unit represented by the general formula (1) is preferably 20 mol% or more, particularly preferably. Is 40 to 100 mol%.
[0050]
Although the specific example of the cationic polymer which has a repeating unit represented by General formula (1) based on this invention is shown below, this invention is not limited to these.
[0051]
[Chemical 3]

[0052]
[Formula 4]

[0053]
[Chemical formula 5]

[0054]
The average molecular weight of the cationic polymer is generally 3000 to 200,000, preferably 5000 to 100,000. The average molecular weight is represented by a value in terms of polyethylene glycol determined from gel permeation chromatography.
[0055]
The amount of the cationic polymer according to the present invention is 1 m for recording paper. ² It is generally 0.1 to 10 g, preferably 0.2 to 5 g.
[0056]
The surface layer according to the present invention can appropriately contain a water-soluble binder in addition to the above-described configuration.
[0057]
Examples of the water-soluble binder include polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, color ginan (κ, ι, λ, etc.), agar, pullulan, water-soluble polyvinyl butyral. , Hydroxyethyl cellulose, carboxymethyl cellulose and the like. Two or more of these water-soluble resins can be used in combination.
[0058]
The water-soluble resin preferably used in the present invention is polyvinyl alcohol. The polyvinyl alcohol preferably used in the present invention includes, in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, modified polyvinyl alcohol such as polyvinyl alcohol having a cation-modified terminal and anion-modified polyvinyl alcohol having an anionic group. Alcohol is also included.
[0059]
The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1,000 or more, and particularly preferably has an average degree of polymerization of 1,500 to 5,000. The saponification degree is preferably 70 to 100%, particularly preferably 80 to 99.5%.
[0060]
Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups in the main chain or side chain of the polyvinyl alcohol as described in JP-A No. 61-10383. It is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.
[0061]
Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1, 1-dimethyl-3-dimethylaminopropyl) acrylamide and the like.
[0062]
The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate.
[0063]
Anion-modified polyvinyl alcohol is described in, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-206088, JP-A-61-237681, and JP-A-63-307979. Examples thereof include a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and modified polyvinyl alcohol having a water-soluble group as described in JP-A-7-285265.
[0064]
Nonionic modified polyvinyl alcohol includes, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group as described in JP-A-7-9758 is added to a part of vinyl alcohol, and JP-A-8-25795. The block copolymer of the vinyl compound and vinyl alcohol which have the described hydrophobic group is mentioned.
[0065]
Polyvinyl alcohol can be used in combination of two or more, such as the degree of polymerization and the type of modification.
[0066]
The amount of inorganic fine particles used in the recording layer depends largely on the required ink absorption capacity, the porosity of the recording layer, the type of inorganic fine particles, and the type of water-soluble resin. ² Usually, it is 5 to 30 g, preferably 10 to 25 g.
[0067]
The ratio of the inorganic fine particles and the water-soluble resin used in the recording layer is usually 2: 1 to 20: 1 by mass ratio, and particularly preferably 3: 1 to 10: 1.
[0068]
The ionic resin used for the recording layer is an inkjet recording medium 1 m. ² Usually, it is used in the range of 0.1 to 10 g, preferably 0.2 to 5 g.
[0069]
In the recording layer, the total amount of voids (void volume) is 1 m on the recording medium. ² It is preferably 20 ml or more per unit. The void volume is 20ml / m ² If the amount of ink is less, the ink absorbency is good when the amount of ink at the time of printing is small, but when the amount of ink increases, the ink is not completely absorbed, resulting in a decrease in image quality or a delay in drying. The problem is likely to occur.
[0070]
In this invention, it is preferable that the porosity of layers other than the above-mentioned outermost layer and outermost layer is 30 to 70%.
[0071]
The porosity can be obtained according to the following formula as one method.
Porosity = 100 × [(total dry film thickness−applied solid film thickness) / (total dry film thickness)]
The porosity can also be measured by the following method. For example, it can be easily obtained by applying a recording layer on 100 μm polyethylene terephthalate and measuring the saturation transition amount or the water absorption amount by Bristow measurement.
[0072]
Next, the support used in the ink jet recording medium according to the present invention will be described.
[0073]
The support used in the present invention is a support conventionally used for inkjet recording media, for example, a paper support such as plain paper, art paper, coated paper and cast-coated paper, a plastic support, and both sides made of polyolefin. Although a coated paper support and a composite support obtained by bonding them together can be used, it is preferable to use a non-water-absorbing support from the viewpoint of further exerting the effects of the present invention.
[0074]
Examples of the non-water-absorbing support used in the present invention include a plastic resin film support or a support in which both surfaces of paper are covered with a plastic resin film. Examples of the plastic resin film support include a polyester film, a polyvinyl chloride film, a polypropylene film, a cellulose triacetate film, a polystyrene film, and a film support in which these are laminated. These plastic resin films can be transparent or translucent.
[0075]
In the present invention, a particularly preferable support is a support in which both sides of paper are coated with a plastic resin, and most preferable is a support in which both sides of paper are coated with a polyolefin resin.
[0076]
Hereinafter, a support in which both sides of paper, which is a particularly preferable support in the present invention, is coated with a polyolefin resin will be described.
[0077]
The paper used for the support according to the present invention is made from wood pulp as a main raw material and, if necessary, using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp. As wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, and NUKP can be used, but it is preferable to use more LBKP, NBSP, LBSP, NDP, and LDP with a large amount of short fibers. However, the ratio of LBSP and / or LDP is preferably 10 to 70%. The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.
[0078]
In paper, for example, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc, and titanium oxide, paper strength enhancers such as starch, polyacrylamide, and polyvinyl alcohol, fluorescent whitening agents, polyethylene Water retaining agents such as glycols, dispersants, softening agents such as quaternary ammonium, and the like can be added as appropriate.
[0079]
The freeness of the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the sum of the 24 mesh residue and the 42 mesh residue whose fiber length after beating is defined in JIS P 8207 is 30 to 70% is preferred. The 4 mesh residue is preferably 20% or less.
[0080]
The basis weight of the paper is preferably 50 to 250 g, particularly preferably 70 to 200 g. The thickness of the paper is preferably 50 to 210 μm.
[0081]
The paper can also be given a high smoothness by calendering at the paper making stage or after paper making. Paper density is 0.7-1.2g / cm ³ (JIS P 8118) is common. Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P 8143.
[0082]
A surface sizing agent may be applied to the paper surface, and the same sizing agent that can be added to the base paper can be used as the surface sizing agent.
[0083]
The pH of the paper is preferably 5 to 9 when measured by the hot water extraction method specified in JIS P8113.
[0084]
Next, the polyolefin resin that covers both sides of the paper will be described.
Examples of the polyolefin resin used for this purpose include polyethylene, polypropylene, polyisobutylene, and polyethylene. Polyolefins such as copolymers mainly composed of propylene are preferable, and polyethylene is particularly preferable.
[0085]
Hereinafter, particularly preferred polyethylene will be described.
The polyethylene covering the paper surface and the back surface is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but other LLDPE, polypropylene and the like can also be used in part.
[0086]
In particular, the polyolefin layer on the coating layer side is preferably one in which rutile or anatase type titanium oxide is added therein to improve opacity and whiteness. The titanium oxide content is generally 1 to 20%, preferably 2 to 15%, based on the polyolefin.
[0087]
In the polyolefin layer, a highly heat-resistant coloring pigment or fluorescent brightening agent for adjusting the white background can be added.
[0088]
Examples of the color pigment include ultramarine blue, bitumen blue, cobalt blue, phthalocyanine blue, manganese blue, cerulean, tungsten blue, molybdenum blue, and anthraquinone blue.
[0089]
Examples of the optical brightener include dialkylaminocoumarin, bisdimethylaminostilbene, bismethylaminostilbene, 4-alkoxy-1,8-naphthalenedicarboxylic acid-N-alkylimide, bisbenzoxazolylethylene, dialkylstilbene, etc. Is mentioned.
[0090]
The amount of polyethylene used on the front and back of the paper is selected to optimize the curl at low and high humidity after the recording layer thickness and back layer are provided, but generally the thickness of the polyethylene layer is The range is 15 to 50 μm on the recording layer side and 10 to 40 μm on the back layer side. The ratio of the front and back polyethylene is preferably set so as to adjust the curl that changes depending on the type and thickness of the recording layer, the thickness of the inner paper, etc. 3/1 to 1/3.
[0091]
Further, the polyethylene-coated paper support preferably has the following characteristics (1) to (8).
[0092]
(1) The tensile strength is a strength defined by JIS P 8113, preferably 19.6 to 294N in the vertical direction and 9.8 to 196N in the horizontal direction.
[0093]
(2) The tear strength is a strength defined by JIS P 8116, preferably 0.20 to 2.94N in the longitudinal direction and 0.098 to 2.45N in the lateral direction.
[0094]
(3) The compression modulus is 9.8 kN / cm ² Is preferred.
(4) The opacity is preferably 80% or more, particularly preferably 85 to 98%, when measured by the method specified in JIS P 8138.
[0095]
(5) Whiteness is stipulated in JIS Z 8727 ^* , A ^* , B ^* But L ^* = 80-96, a ^* = -3 to +5, b ^* = -7 to +2 is preferable.
[0096]
(6) The support having a Clark stiffness of 50 to 300 cm 3/100 in the conveyance direction of the recording medium is preferable.
[0097]
(7) The moisture in the base paper is preferably 4 to 10% with respect to the middle paper.
(8) The glossiness on the surface side on which the recording layer is provided (75-degree specular glossiness) is preferably 10 to 90%.
[0098]
Next, the water-based dye ink according to the present invention will be described.
The aqueous dye ink according to the present invention preferably contains at least ionic (both anionic and cationic: hereinafter simply referred to as ionic) resin fine particles, a water-soluble dye, water and an organic solvent. .
[0099]
The polymer constituting the ionic resin fine particles that can be used in the present invention is not particularly limited. For example, acrylic resins (for example, acrylic resins, acrylic-styrene copolymers, acrylic-vinyl acetate copolymers, Acrylic-silicone copolymer), urethane resin, polyester resin, vinyl acetate resin (eg, vinyl acetate resin, vinyl acetate-ethylene copolymer), butadiene resin (eg, styrene-butadiene copolymer, acrylic) Nitrile-butadiene copolymer, etc.), fluorine-based resins, polyamide-based resins and the like. These resin fine particles are usually obtained by an emulsion polymerization method. The surfactants, polymerization initiators, etc. used there may be those used in conventional methods. Regarding the synthesis method of resin fine particles, U.S. Pat. Nos. 2,852,368, 2,853,457, 3,411,911, 3,411,912, 4,197,127, Belgian Patent Nos. 688,882, 691,360, 712,823, JP-B 45-5331, JP-A-60-18540, 51-130217, 58-137831, 55- 50240 and the like.
[0100]
Moreover, the ionic resin fine particles according to the present invention can be easily obtained as a commercial product.
[0101]
Examples of the anionic latex include AE 120 (manufactured by JSR Corporation), Superflex 460 (manufactured by Daiichi Kogyo Seiyaku), Superflex 370 (manufactured by Daiichi Kogyo Seiyaku), and the like.
[0102]
Examples of nonionic latex include Movinyl 730 (manufactured by Clariant), Superflex E-4500 (manufactured by Daiichi Kogyo Seiyaku), Superflex R-5000 (manufactured by Daiichi Kogyo Seiyaku), and the like.
[0103]
Examples of the cationic latex include Superflex 600 (Daiichi Kogyo Seiyaku), Superflex 610 (Daiichi Kogyo Seiyaku), Pateracol IJ-60 (Dainippon Ink). However, the present invention is not limited to the above latex.
[0104]
In the present invention, the average particle size of the ionic resin fine particles is preferably 30 to 100 nm, and most preferably 30 to 70 nm.
[0105]
The average particle size of the ionic resin fine particles can be easily obtained using a commercially available particle size measuring device using a light scattering method or a laser Doppler method, for example, Zetasizer 1000 (manufactured by Malvern).
[0106]
In the water-soluble dye ink according to the present invention, the content of the ionic resin fine particles in the ink is preferably 0.2 to 10% by mass, more preferably 0.5 to 5% by mass. is there. If the addition amount of the ionic resin fine particles is 0.2% by mass or more, a sufficient effect can be exerted on the gas fading property, and if it is 10% by mass or less, the ink discharge property becomes more stable. Further, the increase in ink viscosity during storage can be suppressed, which is more preferable.
[0107]
In the present invention, it is preferable that either the minimum film-forming temperature (MFT) or the glass transition temperature (Tg) of the ionic resin fine particles is 60 ° C. or lower. In the present invention, a film-forming aid may be added in order to control the minimum film-forming temperature of the ionic resin fine particles. The film-forming aid, also called a plasticizer, is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of the polymer latex. For example, “Synthetic Latex Chemistry (Souichi Muroi, published by Kobunshi Shuppankai (1970)” )"It is described in.
[0108]
The water-soluble dye ink according to the present invention contains at least a water-soluble dye, water and an organic solvent in addition to the above ionic resin fine particles.
[0109]
Examples of water-soluble dyes that can be used in the present invention include azo dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, phthalocyanine dyes, triphenylmethane dyes, diphenylmethane dyes, and the like. The compounds are shown below. However, it is not limited to these exemplified compounds.
[0110]
[C. I. Acid Yellow)
1, 3, 11, 17, 18, 19, 23, 25, 36, 38, 40, 42, 44, 49, 59, 61, 65, 67, 72, 73, 79, 99, 104, 110, 114, 116, 118, 121, 127, 129, 135, 137, 141, 143, 151, 155, 158, 159, 169, 176, 184, 193, 200, 204, 207, 215, 219, 220, 230, 232, 235, 241, 242, 246
[C. I. Acid Orange)
3, 7, 8, 10, 19, 24, 51, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140, 142, 144, 149, 152, 156, 162, 166, 168
[C. I. Acid Red)
1, 6, 8, 9, 13, 18, 27, 35, 37, 52, 54, 57, 73, 82, 88, 97, 106, 111, 114, 118, 119, 127, 131, 138, 143, 145, 151, 183, 195, 198, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 265, 266, 274, 276, 277, 289, 296, 299, 315, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415
[C. I. Acid Violet)
17, 19, 21, 42, 43, 47, 48, 49, 54, 66, 78, 90, 97, 102, 109, 126
[C. I. Acid Blue)
1, 7, 9, 15, 23, 25, 40, 62, 72, 74, 80, 83, 90, 92, 103, 104, 112, 113, 114, 120, 127, 128, 129, 138, 140, 142, 156, 158, 171, 182, 185, 193, 199, 201, 203, 204, 205, 207, 209, 220, 221, 224, 225, 229, 230, 239, 249, 258, 260, 264, 278, 279, 280, 284, 290, 296, 298, 300, 317, 324, 333, 335, 338, 342, 350
[C. I. Acid Green)
9, 12, 16, 19, 20, 25, 27, 28, 40, 43, 56, 73, 81, 84, 104, 108, 109
[C. I. Acid Brown)
2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413
[C. I. Acid Black)
1, 2, 3, 24, 26, 31, 50, 52, 58, 60, 63, 107, 109, 112, 119, 132, 140, 155, 172, 187, 188, 194, 207, 222
[C. I. Direct yellow)
8, 9, 10, 11, 12, 22, 27, 28, 39, 44, 50, 58, 86, 87, 98, 105, 106, 130, 132, 137, 142, 147, 153
[C. I. (Direct orange)
6, 26, 27, 34, 39, 40, 46, 102, 105, 107, 118
[C. I. (Direct Red)
2, 4, 9, 23, 24, 31, 54, 62, 69, 79, 80, 81, 83, 84, 89, 95, 212, 224, 225, 226, 227, 239, 242, 243, 254
[C. I. Direct violet)
9, 35, 51, 66, 94, 95
[C. I. (Direct blue)
1, 15, 71, 76, 77, 78, 80, 86, 87, 90, 98, 106, 108, 160, 168, 189, 192, 193, 199, 200, 201, 202, 203, 218, 225, 229, 237, 244, 248, 251, 270, 273, 274, 290, 291
[C. I. (Direct Green)
26, 28, 59, 80, 85
[C. I. (Direct Brown)
44, 106, 115, 195, 209, 210, 222, 223
[C. I. (Direct Black)
17, 19, 22, 32, 51, 62, 108, 112, 113, 117, 118, 132, 146, 154, 159, 169
[C. I. Basic yellow)
1, 2, 11, 13, 15, 19, 21, 28, 29, 32, 36, 40, 41, 45, 51, 63, 67, 70, 73, 91
[C. I. Basic orange)
2, 21, 22
[C. I. (Basic Red)
1, 2, 12, 13, 14, 15, 18, 23, 24, 27, 29, 35, 36, 39, 46, 51, 52, 69, 70, 73, 82, 109
[C. I. Basic violet)
1, 3, 7, 10, 11, 15, 16, 21, 27, 39
[C. I. (Basic Blue)
1, 3, 7, 9, 21, 22, 26, 41, 45, 47, 52, 54, 65, 69, 75, 77, 92, 100, 105, 117, 124, 129, 147, 151
[C. I. Basic green)
1, 4
[C. I. Basic brown)
1
[C. I. (Reactive Yellow)
2, 3, 7, 15, 17, 18, 22, 23, 24, 25, 27, 37, 39, 42, 57, 69, 76, 81, 84, 85, 86, 87, 92, 95, 102, 105, 111, 125, 135, 136, 137, 142, 143, 145, 151, 160, 161, 165, 167, 168, 175, 176
[C. I. (Reactive Orange)
1, 4, 5, 7, 11, 12, 13, 15, 16, 20, 30, 35, 56, 64, 67, 69, 70, 72, 74, 82, 84, 86, 87, 91, 92, 93, 95, 107
[C. I. (Reactive Red)
2, 3, 5, 8, 11, 21, 22, 23, 24, 28, 29, 31, 33, 35, 43, 45, 49, 55, 56, 58, 65, 66, 78, 83, 84, 106, 111, 112, 113, 114, 116, 120, 123, 124, 128, 130, 136, 141, 147, 158, 159, 171, 174, 180, 183, 184, 187, 190, 193, 194, 195, 198, 218, 220, 222, 223, 228, 235
[C. I. (Reactive Violet)
1, 2, 4, 5, 6, 22, 23, 33, 36, 38
[C. I. (Reactive Blue)
2, 3, 4, 5, 7, 13, 14, 15, 19, 21, 25, 27, 28, 29, 38, 39, 41, 49, 50, 52, 63, 69, 71, 72, 77, 79, 89, 104, 109, 112, 113, 114, 116, 119, 120, 122, 137, 140, 143, 147, 160, 161, 162, 163, 168, 171, 176, 182, 184, 191, 194, 195, 198, 203, 204, 207, 209, 211, 214, 220, 221, 222, 231, 235, 236
[C. I. (Reactive Green)
8, 12, 15, 19, 21
[C. I. (Reactive Brown)
2, 7, 9, 10, 11, 17, 18, 19, 21, 23, 31, 37, 43, 46
[C. I. (Reactive Black)
5, 8, 13, 14, 31, 34, 39
These dyes listed above are described in “Dyeing Note 21st Edition” (publishing; Color Dyeing Company) and the like.
[0111]
The organic solvent that can be used in the present invention is not particularly limited, but is preferably a water-soluble organic solvent. Specifically, alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, Tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexane) Diol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (eg ethylene glycol) Monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl Ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, triethylene glycol dimethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol dimethyl Ethers), amines (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethylene Imine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocyclics (eg, 2-pyrrolidone, N-methyl- 2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, etc.), sulfoxides (for example, dimethyl sulfoxide) Etc.), sulfones (for example, sulfolane), sulfonates (for example, 1-butanesulfonic acid sodium salt), urea, acetonitrile, acetone and the like.
[0112]
Various surfactants can be used in the water-soluble dye ink according to the present invention. Each surfactant that can be used in the present invention is not particularly limited, and examples thereof include anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl ethers, and the like. Nonionic surfactants such as oxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. In particular, anions having the same polarity as the resin fine particles, or cationic surfactants and nonionic surfactants can be preferably used.
[0113]
In the ink of the present invention, a polymer surfactant can also be used. For example, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer, styrene-maleic acid-acrylic acid. Alkyl ester copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid half ester copolymer, vinyl naphthalene-acrylic acid A copolymer, a vinyl naphthalene-maleic acid copolymer, etc. can be mentioned.
[0114]
In the water-soluble dye ink according to the present invention, in addition to the above description, depending on the purpose of improving the emission stability, print head and ink cartridge compatibility, storage stability, image storage stability, and other various performances as necessary. Various known additives such as viscosity modifiers, specific resistance modifiers, film forming agents, ultraviolet absorbers, antioxidants, anti-fading agents, anti-fouling agents, rust inhibitors, etc. are appropriately selected and used. For example, oil droplet fine particles such as liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil, ultraviolet absorbers described in JP-A-57-74193, 57-87988 and 62-261476, JP-A-57-74192, JP-A-57-87989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091 and JP-A-3-13376. Fluorescent whitening described in JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, JP-A-4-219266 and the like An agent etc. can be mentioned.
[0115]
The ink jet head used in the ink jet recording method of the present invention may be an on-demand system or a continuous system. As the discharge method, an electro-mechanical conversion method (for example, single cavity type, double cavity type, bender type, piston type, shear mode type, shared wall type, etc.), electro-thermal conversion method (for example, thermal ink jet) Specific examples include a mold, a bubble jet (R) type, an electrostatic attraction method (for example, an electric field control type, a slit jet type), and a discharge method (for example, a spark jet type). Any discharge method may be used.
[0116]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
[0117]
Example 1
<Production of recording medium>
(Preparation of silica dispersion D1)
25% by mass of gas phase method silica (Nippon Aerosil Co., Ltd .: Aerosil 50) having an average particle size of primary particles uniformly dispersed in advance of about 0.040 μm, water-soluble fluorescent whitening agent UVITEXNFW LIQUID (Ciba Specialty) 400 L of silica dispersion B1 (pH = 2.3, containing 1% by mass of ethanol) containing 0.3% by mass of Chemicals), 12% by mass of the cationic polymer (P-1), and 10 of n-propanol It was added to 110 L of an aqueous solution C1 containing 2% by mass and 2% by mass of ethanol (pH = 2.5, containing 2 g of antifoam SN381 manufactured by Sannobuco) with stirring at 3000 rpm at room temperature. Next, 54 L of a mixed aqueous solution A1 (concentration of 3% by mass) of boric acid and borax in a 1: 1 mass ratio was gradually added with stirring.
[0118]
Next, with a high-pressure homogenizer manufactured by Sanwa Industry Co., Ltd., 3 kN / cm ² And the whole amount was finished to 630 L with pure water to obtain a substantially transparent silica dispersion D1.
[0119]
The silica dispersion D1 was filtered using a TCP-30 type filter manufactured by Advantech Toyo Co., Ltd. having a filtration accuracy of 30 μm.
[0120]
(Preparation of silica dispersion D2)
In the preparation of the silica dispersion D1, 400 L of the silica dispersion B1 was added to an aqueous solution C2 containing 12% by mass of the cationic polymer (P-2), 10% by mass of n-propanol and 2% by mass of ethanol (pH = 2.5) was added while stirring at 3000 rpm at room temperature, and then a silica dispersion D2 was prepared in the same manner except that 52 L of the mixed aqueous solution A1 was gradually added with stirring.
[0121]
(Preparation of silica dispersion D3)
In the preparation of the silica dispersion D2, a silica dispersion D3 was prepared in the same manner except that 120 L of an aqueous solution C3 containing 10% by mass of n-propanol and 2% by mass of ethanol was added instead of the aqueous solution C2.
[0122]
(Preparation of silica dispersion D4)
In the preparation of the silica dispersion D1, the silica dispersion D4 was similarly used except that the anionic polymer (PA) (polyvinylsulfonic acid polymerization degree 2000) was used instead of the cationic polymer (P-1). Was prepared.
[0123]
(Preparation of oil dispersion)
Gelatin aqueous solution containing 20 kg of diisodecyl phthalate and 20 kg of antioxidant (AO-1) dissolved in 45 kg of ethyl acetate by heating, 8 kg of acid-treated gelatin, 2.9 kg of cationic polymer P-1 and 10.5 kg of saponin After mixing with 210 L at 55 ° C. and emulsifying and dispersing with a high-pressure homogenizer, the entire amount was finished to 300 L with pure water to prepare an oil dispersion.
[0124]
[Chemical 6]

[0125]
(Preparation of coating solution)
Using the dispersions prepared above, the additives described below were sequentially mixed to prepare a coating solution. In addition, each addition amount was displayed by the quantity per 1L of coating liquids.
[0126]

The whole volume was finished to 1000ml with pure water.
In addition, the mass ratio of the cationic polymer (P-2) and the inorganic pigment fine particles (Aerosil 50) in the outermost layer is 1: 6.9.
[0127]
[Chemical 7]

[0128]
Each coating solution prepared as described above was filtered with a TCPD-30 filter manufactured by Advantech Toyo Co., Ltd. having a filtration accuracy of 20 μm, and then filtered with a TCPD-10 filter.
[0129]
(Application)
Next, four layers of each of the above coating solutions were simultaneously coated on a paper support 1 coated with polyethylene on both sides at 40 ° C. using a slide hopper type coater so that the wet film thickness described below was obtained.
[0130]
<Wet film thickness>
First layer: 42 μm
Second layer: 39 μm
Third layer: 44 μm
Outermost layer: 4μm
In addition, the paper support 1 used above has a water content of 8% and a basis weight of 170 g of a photographic base paper surface. The polyethylene containing 6% of anatase-type titanium oxide is extruded and melt coated at a thickness of 35 μm. Polyethylene having a thickness of 40 μm was extruded and melt coated on the back surface. On the surface side, after corona discharge, polyvinyl alcohol (PVA235 manufactured by Kuraray Co., Ltd.) was used as the recording medium 1 m. ² After applying an undercoat layer to 0.05 g per unit and corona discharge processing on the back side, about 0.4 g of a styrene / acrylate ester latex binder having a Tg of about 80 ° C., an antistatic agent (cationic) A back layer containing 0.1 g of polymer) and 0.1 g of about 2 μm silica as a matting agent was applied.
[0131]
The drying after applying the recording layer coating liquid is performed by passing through a cooling zone maintained at 5 ° C. for 15 seconds to lower the film surface temperature to 13 ° C. After appropriately setting the temperature and drying, the recording medium 1 was obtained by winding in a roll.
[0132]
[Preparation of recording medium 2]
A recording medium 2 was produced in the same manner as in the production of the recording medium 1 except that the cationic polymer (P-2) used in the outermost layer was removed by using the silica dispersion D3.
[0133]
[Preparation of recording medium 3]
In the production of the recording medium 1, the cationic polymer (P-1) used in the first and second layers and the cationic polymer (P-2) used in the third and outermost layers are used in the silica dispersion D3. A recording medium 3 was produced in the same manner except for the above.
[0134]
[Preparation of recording medium 4]
In the production of the recording medium 1, the silica dispersion D4 is used for the cationic polymer (P-1) used in the first and second layers and the cationic polymer (P-2) used in the third and outermost layers. Thus, a recording medium 4 was produced in the same manner except that the anionic polymer (PA) was used.
[0135]
[Preparation of recording medium 5]
A recording medium 5 was produced in the same manner as in the production of the recording medium 4 except that the anionic polymer (PA) used in the outermost layer was removed by using the silica dispersion D3.
[0136]
<< Preparation of water-based dye ink >>
[Preparation of dye ink 1]
Anionic dyes C.I. I. Direct Black 108 5% by mass
Anionic latex AE120 (manufactured by JSR Corporation) 2% by mass
Diethylene glycol 25% by mass
Dioctyl sodium sulfosuccinate 0.01% by mass
Dye ink 1 was prepared by finishing 100% by mass with water.
[0137]
[Preparation of dye inks 2 to 6]
Dye inks 2 to 6 were prepared in the same manner except that each resin fine particle (latex) shown in Table 1 was added instead of the anionic latex AE120 of the dye ink 1.
[0138]
[Preparation of dye inks 7 to 9]
In the dye ink 1, the anionic dye is a cationic dye C.I. I. Dye inks 7 to 9 were prepared in the same manner except that each resin fine particle (latex) shown in Table 1 was added instead of Basic Blue 199 instead of anionic latex AE120.
[0139]
[Preparation of dye ink 10]
A dye ink 10 was prepared in the same manner as in the dye ink 1 except that the anionic latex AE120 was omitted.
[0140]
In addition, the average particle diameter of each resin fine particle (latex) was measured using a laser Doppler type Zeta Sizer 1000 (manufactured by Malvern).
[0141]
[Table 1]

[0142]
<< Inkjet image formation >>
MJ800C manufactured by Seiko Epson Corporation is used as the printer, and the ink cartridges equipped in the printer are loaded with the prepared dye inks 1 to 10, respectively. As 10ml / m ² A solid image was printed so that the images 1 to 25 were output.
[0143]
The ink set was stored in an oven at 60 ° C. for 72 hours, and a solid image was printed in the same manner.
[0144]
<< Measurement and evaluation of inkjet images >>
The cyan image formed as described above was measured and evaluated according to the following methods.
[0145]
(Evaluation of gas fading resistance)
Each solid image was exposed at 23 ° C. in an environment with an ozone concentration of 50 ppm for 120 minutes, and then the reflection density before and after the exposure was measured with a red monochromatic light of an optical densitometer (X-Rite 938 manufactured by X-Rite). The image residual ratio was determined according to the following formula, and gas fading resistance was evaluated according to the following criteria.
[0146]
Image residual ratio = density after exposure / density before exposure x 100 (%)
5: Image remaining ratio is 95% or more
4: Image residual ratio is less than 85-95%
3: Image residual ratio is less than 70 to 85%
2: Image remaining ratio is less than 60 to 70%
1: Image remaining ratio is less than 60%.
[0147]
(Evaluation of glossiness (C value))
The created solid image was measured for image clarity (gloss value C value%) at a reflection of 60 degrees and an optical comb of 2 mm with a image clarity measuring instrument ICM-1DP (manufactured by Suga Test Instruments Co., Ltd.). In practice, the C value is preferably 70 or more, more preferably 80 or more, particularly preferably 85 or more, and less than 70 has poor practicality.
[0148]
(Evaluation of color development)
The reflection density of the created solid image was measured with red monochromatic light of an optical densitometer (X-Rite 938 manufactured by X-Rite), and the color development was evaluated according to the following.
○: 0.95 to 1.0 times the density of image number 25
Δ: The density is 0.94 times or less than the image number 25
[0149]
[Table 2]

[0150]
As is clear from Table 2, the image produced with the ink containing resin particles was excellent in gas fading resistance.
[0151]
It was also found that high image clarity can be obtained by using a recording medium that does not contain an ionic mordant in the uppermost layer.
[0152]
Further, it was found that the C value obtained by printing remains high even after storing the ink because the resin particles have ionicity.
[0153]
It was also found that it is more desirable in terms of color development to contain an ionic mordant in the recording medium.
[0154]
Example 2
[Preparation of recording media 6 to 17]
In the production of the recording medium 2, recording media 6 to 17 were produced in the same manner except that the particle diameter of the inorganic pigment particles (gas phase method silica) used in the outermost layer was changed as shown in Table 3.
[0155]
[Preparation of dye inks 11 to 22]
Dye inks 11 to 22 were prepared in the same manner except that the particle size of the anionic latex AE120 of the dye ink 1 was changed to the particle size shown in Table 3.
[0156]
[Production of images 26 to 50]
In the same manner as in the method described in Example 1, the recording medium and ink described in Table 3 were combined to form an image.
[0157]
(Evaluation of gloss coloring)
White light was applied to the created solid image at an incident angle of 60 ° C., and the color of the directly reflected light was visually evaluated.
Red: The reflected light is colored red
Yellow: The reflected light is colored yellow
Blue: Reflected light is colored blue
White: no color
The glossiness was evaluated in the same manner as in Example 1, and the results are shown in Table 3.
[0158]
[Table 3]

[0159]
As is apparent from Table 3, the primary particle diameter of the inorganic pigment particles of the recording material is preferably 30 nm or more because the reflected light is not tinted. If the primary particle diameter is 100 nm or less, the C value is 80 or more. Is preferable.
[0160]
Further, if the resin particle size in the ink is 30 nm or more, it is preferable because the reflected light is not colored, and if it is 100 nm or less, a C value of 80 or more is obtained.
[0161]
Example 3
[Preparation of recording media 18 to 27]
Recording media 18 to 27 were produced in the same manner except that the thickness of the outermost layer was changed as shown in Table 3 in the production of the recording medium 2.
[0162]
[Production of images 51 to 61]
In the same manner as in the method described in Example 1, the recording medium described in Table 4 and ink were combined to produce an image.
[0163]
(Evaluation of beading)
The surface of the produced solid image was visually observed, and the presence or absence of a beading phenomenon in which the ink absorption speed was slow and ink droplets were mixed on the recording material was evaluated.
○: not seen at all
△: seen in some
×: Seen on the entire print surface
The glossiness was evaluated in the same manner as in Example 1, and the results are shown in Table 4.
[0164]
[Table 4]

[0165]
As is apparent from Table 4, when the outermost layer thickness is 0.1 μm or more, aggregation of latex particles on the media rhombus during ink ejection is suppressed, and high gloss is obtained. If the outermost layer thickness is 10 μm or less, the beading becomes hardly noticeable.
[0166]
【The invention's effect】
According to the present invention, an ink jet recording method excellent in gas fading resistance, glossiness, glossy reflected light color, and image beading resistance can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a conventional inkjet recording medium during recording.
FIG. 2 is a schematic diagram at the time of recording on the ink jet recording medium according to the present invention.
[Explanation of symbols]
1 Support
2 Ink absorption layer
3 outermost layer
4 Cationic mordant
5 Ink droplet

Claims (6)

An ink jet recording method comprising recording an image by ejecting an aqueous dye ink containing ionic resin fine particles onto an ink jet recording medium having a recording layer containing no ionic mordant. An inkjet recording medium has a plurality of recording layers, and an image is recorded by ejecting aqueous dye ink containing ionic resin fine particles onto an inkjet recording medium that does not contain ionic resin particles only in the outermost layer on the recording surface side. An inkjet recording method characterized by the above. 3. The ink jet recording method according to claim 1, wherein the recording layer of the ink jet recording medium is a void type. The inkjet recording medium according to any one of claims 1 to 3, wherein the inkjet recording medium contains fine particles in an outermost layer on the recording surface side, and the primary particle diameter of the fine particles is 30 to 100 nm. Method. The inkjet recording method according to any one of claims 1 to 4, wherein the particle diameter of the ionic resin fine particles contained in the aqueous dye ink is 30 to 100 nm. 6. The ink jet recording method according to claim 1, wherein the outermost layer on the recording surface side of the ink jet recording medium has a thickness of 100 nm to 10 [mu] m.

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