JP4056260B2 - Aqueous recording liquid, and recording method, ink cartridge, and ink jet recording apparatus using the aqueous recording liquid - Google Patents

Description

【００７８】
上記化合物は、単独で用いてもよく、複数のものを混合して用いてもよい。市販の界面活性剤で本化合物を主成分として含有するものとしては、日光ケミカルズ（株）より入手可能なＥＣＴＤ３ＮＥＸ（前記一般式（１）において、Ｒ₁：トリデシル基、ｍ：３、Ｍ：Ｎａ）、ＥＣＴ３（Ｒ₁：トリデシル基、ｍ：３、Ｍ：Ｈ）、ＥＣＴＤ６ＮＥＸ（Ｒ₁：トリデシル基、ｍ：６、Ｍ：Ｎａ）等の界面活性剤も使用可能である。
【００７９】
前記一般式（１）で表される化合物の対イオンとして、アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、またはアルカノールアミンを用いることにより、優れた溶解安定性を示す。更に、対イオンとしてナトリウム、リチウムおよび／または下記一般式(２)で表される第４級アンモニウム、第４級ホスホニウム、アルカノールアミン陽イオンを用いると、より一層溶解安定性が増して更に好ましい。
【００８０】
【化５】

【００８１】
（式中、Ｙは窒素またはリンを表し、Ｒ₁〜Ｒ₄は各々水素原子、炭素数１〜４のアルキル基、ヒドロキシアルキル基、ハロゲン化アルキル基を表す。）
【００８２】
前記一般式（１）の対イオンとして、例えばリチウム塩を用いる場合には、水酸化リチウムを添加することにより行われ、一般式（２)の第４級アンモニウム、ホスホニウム、アルカノールアミン陽イオン等を用いる場合には、具体的には下記式（２−１）〜（２−９）に示す水酸化物を添加することにより行われる。
【００８３】
【化６】

【００８４】
【化７】

【００８５】
【化８】

【００８６】
【化９】

【００８７】
【化１０】

【００８８】
【化１１】

【００８９】
【化１２】

【００９０】
【化１３】

【００９１】
【化１４】

【００９２】
また、２，４−ジエチル−１，５−ペンタンジオール以外に表面張力を調整する等の目的で添加される浸透剤としては、ジエチレングリコールモノフェニルエーテル、エチレングリコールモノフェニルエーテル、エチレングリコールモノアリルエーテル、ジ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ブチルエーテル、トリエチレングリコールモノブチルエーテル、プロピレングリコールモノブチルエーテル、テトラエチレングリコールクロロフェニルエーテル等の多価アルコールのアルキルおよびアリールエーテル類、フッ素系界面活性剤、エタノール、２−プロパノール等の低級アルコール類が挙げられるが、特に好ましいのはジエチレングリコールモノブチルエーテルまたはトリエチレングリコールモノブチルエーテルである。
【００９３】
本発明に用いられる色材としては、顔料および／または染料のいずれであってもよい。色材として用いられる水溶性染料としては、カラーインデックスにおいて酸性染料、直接性染料、塩基性染料、反応性、食用染料に分類される染料が用いられる。これら染料は複数の種類を混合して用いてもよいし、あるいは必要に応じて顔料等の他の色素と混合して用いてもよい。これら色材は本発明の効果を妨げない範囲で添加される。
これら染料の具体例を下記に挙げる。
【００９４】
酸性染料および食用染料として、Ｃ．Ｉ．アシッド・イエロー１７、２３、４２、４４、７９、１４２；Ｃ．Ｉ．アシッド・レッド１、８、１３、１４、１８、２６、２７、３５、３７、４２、５２、８２、８７、８９、９２、９７、１０６、１１１、１１４、１１５、１３４、１８６、２４９、２５４、２８９；Ｃ．Ｉ．アシッド・ブルー９、２９、４５、９２、２４９；Ｃ．Ｉ．アシッド・ブラック１、２、７、２４、２６、９４；Ｃ．Ｉ．フード・イエロー２、３、４；Ｃ．Ｉ．フード・レッド７、９、１４；Ｃ．Ｉ．フード・ブラック１、２
等が挙げられる。
【００９５】
直接性染料として、Ｃ．Ｉ．ダイレクト・イエロー１、１２、２４、２６、３３、４４、５０、１２０、１３２、１４２、１４４、８６；Ｃ．Ｉ．ダイレクト・レッド１、４、９、１３、１７、２０、２８、３１、３９、８０、８１、８３、８９、２２５、２２７；Ｃ．Ｉ．ダイレクト・オレンジ２６、２９、６２、１０２；Ｃ．Ｉ．ダイレクト・ブルー１、２、６、１５、２２、２５、７１、７６、７９、８６、８７、９０、９８、１６３、１６５、１９９、２０２；Ｃ．Ｉ．ダイレクト・ブラック１９、２２、３２、３８、５１、５６、７１、７４、７５、７７、１５４、１６８、１７１
等が挙げられる。
【００９６】
塩基性染料として、Ｃ．Ｉ．ベーシック・イエロー１、２、１１、１３、１４、１５、１９、２１、２３、２４、２５、２８、２９、３２、３６、４０、４１、４５、４９、５１、５３、６３、４６５、６７、７０、７３、７７、８７、９１；Ｃ．Ｉ．ベーシック・レッド２、１２、１３、１４、１５、１８、２２、２３、２４、２７、２９、３５、３６、３８、３９、４６、４９、５１、５２、５４、５９、６８、６９、７０、７３、７８、８２、１０２、１０４、１０９、１１２；Ｃ．Ｉ．ベーシック・ブルー１、３、５、７、９、２１、２２、２６、３５、４１、４５、４７、５４、６２、６５、６６、６７、６９、７５、７７、７８、８９、９２、９３、１０５、１１７、１２０、１２２、１２４、１２９、１３７、１４１、１４７、１５５；Ｃ．Ｉ．ベーシック・ブラック２、８
等が挙げられる。
【００９７】
反応性染料として、Ｃ．Ｉ．リアクティブ・ブラック３、４、７、１１、１２、１７；Ｃ．Ｉ．リアクテイブ・イエロー１、５、１１、１３、１４、２０、２１、２２、２５、４０、４７、５１、５５、６５、６７；Ｃ．Ｉ．リアクティブ・レッド１、１４、１７、２５、２６、３２、３７、４４、４６、５５、６０、６６、７４、７９、９６、９７；Ｃ．Ｉ．リアクティブ・ブルー１、２、７、１４、１５、２３、３２、３５、３８、４１、６３、８０、９５
等が挙げられる。
【００９８】
染料としては、特に酸性染料および直接性染料が好ましく用いることができ、本発明の水性記録液の溶解安定性の向上や、色調、耐水性、耐光性で優れた効果が得られる。インク組成物中の色材としての染料の添加量は、０．５〜２５重量％が好ましく、より好ましくは２〜１５重量％である。
【００９９】
顔料は、特にその種類を限定することなく、無機顔料、有機顔料を使用することができる。染料に比べてインク中で溶解せずに粒子として分散しているので、同じ浸透特性のインクであっても紙の奥深くに浸透しにくく、このため画像濃度も高く、裏抜けの少ない良好な画質を得ることが可能になる。
【０１００】
無機顔料としては、酸化チタン、酸化鉄、炭酸カルシウム、硫酸バリウム、水酸化アルミニウム、バリウムイエロー、カドミウムレッド、クロムイエロー、あるいはコンタクト法、ファーネス法、サーマル法などの公知の方法によって製造されたカーボンブラックを使用することができる。また、有機顔料としては、アゾ顔料（アゾレーキ、不溶性アゾ顔料、縮合アゾ顔料、キレートアゾ顔料などを含む）、多環式顔料（例えば、フタロシアニン顔料、ぺリレン顔料、ぺリノン顔料、アントラキノン顔料、キナクリドン顔料、ジオキサジン顔料、インジゴ顔料、チオインジゴ顔料、イソインドリノン顔料、キノフラロン顔料など）、染料キレート（例えば、塩基性染料型キレート、酸性染料型キレートなど）、ニトロ顔料、ニトロソ顔料あるいはアニリンブラックなどが使用できる。これらの顔料の中で、特に水と親和性の良いものが好ましく用いられる。インク組成物中の色材としての顔料の添加量は、０．５〜２５重量％が好ましく、より好ましくは２〜１５重量％である。
【０１０１】
本発明において好ましく用いられる顔料の具体例を以下に示す。
黒色用としては、ファーネスブラック、ランプブラック、アセチレンブラック、チャンネルブラック等のカーボンブラック（Ｃ．Ｉ．ピグメントブラック７）類、または銅、鉄（Ｃ．Ｉ．ピグメントブラック１１）、酸化チタン等の金属類、アニリンブラック（Ｃ．Ｉ．ピグメントブラック１）等の有機顔料が挙げられる。更に、カラー用としては、Ｃ．Ｉ．ピグメントイエロー１、３、１２、１３、１４、１７、２４、３４、３５、３７、４２（黄色酸化鉄）、５３、５５、８１、８３、９５、９７、９８、１００、１０１、１０４、４０８、１０９、１１０、１１７、１２０、１３８、１５０、１５３；Ｃ．Ｉ．ピグメントオレンジ５、１３、１６、１７、３６、４３、５１；Ｃ．Ｉ．ピグメントレッド１、２、３、５、１７、２２、２３、３１、３８、４８：２、４８：２（パーマネントレッド２Ｂ（Ｃａ））、４８：３、４８：４、４９：１、５２：２、５３：１、５７：１（ブリリアントカーミン６Ｂ）、６０：１、６３：１、６３：２、６４：１、８１、８３、８８、１０１（べんがら）、１０４、１０５、１０６、１０８（カドミウムレッド）、１１２、１１４、１２２（キナクリドンマゼンタ）、１２３、１４６、１４９、１６６、１６８、１７０、１７２、１７７、１７８、１７９、１８５、１９０、１９３、２０９、２１９；Ｃ．Ｉ．ピグメントバイオレット１（ローダミンレーキ）、３、５：１、１６、１９、２３、３８；Ｃ．Ｉ．ピグメントブルー１、２、１５（フタロシアニンブルー）、１５：１、１５：２、１５：３（フタロシアニンブルー）、１６、１７：１、５６、６０、６３；Ｃ．Ｉ．ピグメントグリーン１、４、７、８、１０、１７、１８、３６、等がある。
【０１０２】
色材として用いられるブラック用の顔料としては、カーボンブラックであることが好ましい。ブラックインク用としてカーボンブラックは色調に優れるとともに耐水性、退光性、分散安定性に優れ、かつ安価である。その他顔料（例えばカーボン）の表面を樹脂等で処理して水中に分散可能としたグラフト顔料や、顔料（例えばカーボン）の表面にスルホン基やカルボキシル基等の官能基を付加して水中に分散可能とした加工顔料等が使用できる。また、顔料をマイクロカプセルに包含させ、該顔料を水中に分散可能なのものとしたものであってもよい。
【０１０３】
本発明の好ましい態様によれば、前記インク組成物中の顔料は平均粒径が１０ｎｍ〜２００ｎｍの範囲であることが好ましい。ここで云う平均粒径とは、記録液中のブラウン運動を行っている粒子にレーザー光を照射し、粒子から戻ってくる光（後方散乱光）の振動数（光の周波数）の変化量から粒子径を求める動的光散乱法（ドップラー散乱光解析）を用いて測定した体積累積パーセント５０％の値を指す。
【０１０４】
色材を顔料とすると耐水性や耐光性が良好になり、更に記録媒体の層をインクが抜け、裏面までしみ出してまう裏抜け（以下単に裏抜けと記す）を防止することができる。顔料は、インク組成物からなる水性記録液中に溶解せず分散しているためにインクジェットで印字された際、インクの液体成分に比べて記録媒体の中に入りにくく、記録媒体の表面近傍に留まるため、乾燥性は速く、かつ裏抜けを防止することができる。平均粒径が１０ｎｍ以下であると裏抜けを防止する効果が少なく、２００ｎｍ以上では水性記録液の分散安定性が悪く、保存時に凝集等で粒径が大きくなり吐出安定性が劣る場合がある。
【０１０５】
前記顔料は、分散剤を用いて予め水性媒体中に分散させて顔料分散液とし、この分散液状態でインク組成物として添加されるのが好ましい。好ましい分散剤としては、従来公知の顔料分散液を調整するのに用いられる公知の分散剤を使用することができる。高分子分散剤として例えば以下のものが挙げられる。
【０１０６】
親水性高分子として、天然系ではアラビアガム、トラガンガム、グーアガム、カラヤガム、ローカストビーンガム、アラビノガラクトン、ペクチン、クインスシードデンプン等の植物性高分子、アルギン酸、カラギーナン、寒天等の海藻系高分子、ゼラチン、カゼイン、アルブミン、コラーゲン等の動物系高分子、キサンテンガム、デキストラン等の微生物系高分子、半合成系ではメチルセルロース、エチルセルロース、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース、カルボキシメチルセルロース等の繊維素系高分子、デンプングリコール酸ナトリウム、デンプンリン酸エステルナトリウム等のデンプン系高分子、アルギン酸ナトリウム、アルギン酸プロピレングリコールエステル等の海藻系高分子が挙げられる。
【０１０７】
また、純合成系ではポリアクリル酸、ポリメタクリル酸、アクリル酸−アクリロニトリル共重合体、酢酸ビニル−アクリル酸エステル共重合体、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−メタクリル酸共重合体、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−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−α−メチルスチレン−アクリル酸共重合体、スチレン−α−メチルスチレン−アクリル酸共重合体−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、ビニルナフタレン−マレイン酸共重合体、酢酸ビニル−エチレン共重合体、酢酸ビニル−脂肪酸ビニルエチレン共重合体、酢酸ビニル−マレイン酸エステル共重合体、酢酸ビニル−クロトン酸共重合体、酢酸ビニル−アクリル酸共重合体等が挙げられる。
【０１０８】
上記共重合体は重量平均分子量が３，０００〜５０，０００であるのが好ましく、より好ましくは５，０００〜３０，０００、最も好ましくは７，０００〜１５，０００である。高分子分散剤の添加量は、顔料を安定に分散させ、本発明の他の効果を失わせない範囲で適宣添加されてよい。顔料と分散剤との比としては１：０．０６〜１：３の範囲が好ましく、より好ましくは１：０．１２５〜１：３の範囲である。
【０１０９】
また、水溶性界面活性剤を顔料分散剤として使用することも可能である。この場合、その使用量に対するインク粘度の上昇が高分子分散剤を使用した場合よりも小さく、インクジェット記録法に用いたときに良好な吐出特性の顔料系インクを得やすい。
【０１１０】
顔料分散剤として使用する水溶性界面活性剤としては、アニオン界面活性剤、カチオン界面活性剤、ノニオン系界面活性剤、両性界面活性剤等が使用できるが、分散剤としての界面活性剤の添加量は、顔料を安定に分散させ、本発明の他の効果を失わせない範囲で適宣添加されてよい。以下に具体例を示す。
【０１１１】
例えば、アニオン界面活性剤としては、アルキルアリルまたはアルキルナフタレンスルホン酸塩、アルキルリン酸塩、アルキル硫酸塩、アルキルスルホン酸塩、アルキルエーテル硫酸塩、アルキルスルホコハク酸塩、アルキルエステル硫酸塩、アルキルベンゼンスルホン酸塩、アルキルジフェニルエーテルジスルホン酸塩、アルキルアリールエーテルリン酸塩、アルキルアリールエーテル硫酸塩、アルキルアリールエーテルエステル硫酸塩、オレフィンスルホン酸塩、アルカンオレフィンスルホン酸塩、ポリオキシエチレンアルキルエーテルリン酸塩、ポリオキシエチレンアルキルエーテル硫酸エステル塩、エーテルカルボキシレート、スルホコハク酸塩、α−スルホ脂肪酸エステル、脂肪酸塩、高級脂肪酸とアミノ酸の縮合物、ナフテン酸塩等がある。
【０１１２】
また、カチオン界面活性剤としては、アルキルアミン塩、ジアルキルアミン塩、脂肪族アミン塩、ベンザルコニウム塩、第４級アンモニウム塩、アルキルピリジニウム塩、イミダゾリニウム塩、スルホニウム塩、ホスホニウム塩等がある。
【０１１３】
更に、ノニオン系界面活性剤としては、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルアリルエーテル、ポリオキシエチレンアルキルフェニルエーテル、ポリオキシエチレングリコールエステル、ポリオキシエチレン脂肪酸アミド、ポリオキシエチレン脂肪酸エステル、ポリオキシエチレンポリオキシプロピレングリコール、グリセリンエステル、ソルビタンエステル、ショ糖エステル、グリセリンエステルのポリオキシエチレンエーテル、ソルビタンエステルのポリオキシエチレンエーテル、ソルビトールエステルのポリオキシエチレンエーテル、脂肪酸アルカノールアミド、アミンオキシド、ポリオキシエチレンアルキルアミン、グリセリン脂肪酸エステル、ソルビタン脂肪酸エステル、ポリオキシエチレンソルビタン脂肪酸エステル、ポリオキシエチレンソルビトール脂肪酸エステル、アルキル（ポリ）グリコキシド等がある。
【０１１４】
あるいは、両性界面活性剤としては、イミダゾリニウムベタイン等のイミダゾリン誘導体、ジメチルアルキルラウリルベタイン、アルキルグリシン、アルキルジ（アミノエチル）グリシン等がある。
【０１１５】
インク組成物中の前記分散剤は、カルボキシル基の結合しているものが好ましい。分散剤にカルボキシル基が結合していると分散安定性が向上するばかりではなく、高品位な印字品質が得られると共に印字後の記録媒体の耐水性がより向上する。更に、前記の裏抜けを防止する効果が得られる。特に、カルボキシル基が結合している分散剤で分散した顔料と、２，４−ジエチル−１，５−ペンタンジオールとを併用した場合においては、普通紙などの比較的サイズ度の高い記録媒体に印字した場合においても十分な乾燥速度が得られ、かつ裏抜けが少ないという効果が得られる。この理由は、カルボン酸の解離定数が他の酸基に比較して小さいために顔料が記録媒体に付着した後、インクのｐＨ値の低下や記録媒体表面近傍に存在するカルシウムなどの多価金属イオンとの相互作用などにより、分散剤自体の溶解度が低下して分散剤自体や顔料が凝集することによるものと推定される。
【０１１６】
また、より好ましい別の形態としては、インク組成物中の顔料が表面改質されてカルボキシル基が直接顔料に結合しており、この状態で水中に分散されている形態が挙げられる。この場合、顔料が表面改質されカルボキシル基が結合しているため、分散安定性が向上するばかりではなく、上述と同様な作用により高品位な印字品質が得られると共に印字後の記録媒体の耐水性がより向上する。また、この形態のインクは乾燥後の再分散性に優れるため、長期間印字を休止し、インクジェットヘッド（記録ヘッド）のノズル付近のインクの水分が蒸発した場合も目詰まりを起こさず簡単なクリーニング動作で容易に良好な印字が行えるようになる。
【０１１７】
また、近年急速に普及しつつある不可視記録液によるバーコード印刷、消印印刷への適用も可能である。この場合、通常の染料や顔料に替えて、可視領域に吸収を持たず、赤外線や紫外線に吸収を持つ赤外線吸収剤あるいは紫外線吸収剤がインク組成物中に添加される。
本発明の水性記録液は色材、水、湿潤剤、２，４−ジエチル−１，５−ペンタンジオールを主要成分として含有し、界面活性剤等が適宜添加できるが、その他の従来知られている添加剤を加えることもできる。例えば、本発明の水性記録液には樹脂エマルジョンが添加されていてもよい。
【０１１８】
本発明に用いることのできる樹脂エマルジョンとは、連続相が水であり、分散相が次の様な樹脂成分であるエマルジョンを意味する。すなわち、分散相の樹脂成分としてはアクリル系樹脂、酢酸ビニル系樹脂、スチレン−ブタジエン系樹脂、塩化ビニル系樹脂、アクリル−スチレン系樹脂、ブタジエン系樹脂、スチレン系樹脂などが挙げられる。この樹脂は親水性部分と疎水性部分とを併せ持つ重合体であるのが好ましい。また、これらの樹脂成分の粒子径はエマルジョンを形成する限り特に限定されないが、１５０ｎｍ程度以下が好ましく、より好ましくは５〜１００ｎｍ程度である。これらの樹脂エマルジョンは、樹脂粒子を、場合によって界面活性剤と共に水に混合することによって得ることができる。
【０１１９】
市販の樹脂エマルジョンとしては、例えばマイクロジェルＥ−１００２、Ｅ−５００２（スチレン−アクリル系樹脂エマルジョン：日本ペイント株式会社製）、ボンコート４００１（アクリル系樹脂エマルジョン：大日本インキ化学工業株式会社製）、ボンコート５４５４（スチレン−アクリル系樹脂エマルジョン：大日本インキ化学工業株式会社製）、ＳＡＥ−１０１４（スチレン−アクリル系樹脂エマルジョン：日本ゼオン株式会社製）、サイビノールＳＫ−２００（アクリル系樹脂エマルジョン：サイデン化学株式会社製）等が挙げられる。
【０１２０】
本発明の水性記録液におけるインク組成物は、樹脂エマルジョンを該樹脂成分がインク組成物の０．１〜４０重量％となるよう含有するのが好ましく、より好ましくは１〜２５重量％の範囲である。樹脂エマルジョンは、増粘・凝集する性質を持ち、色材成分の紙深さ方向への浸透を抑制し、更に記録媒体への定着を促進する効果を有する。また、樹脂エマルジョンの種類によっては記録媒体上で皮膜を形成し、印刷物の耐擦性をも向上させる効果を有する。
【０１２１】
また、水性記録液中の水分蒸発を抑制するなどの目的で、インク組成物は糖を含有していてもよい。糖類の例としては、単糖類、二糖類、オリゴ糖類（三糖類および四糖類を含む）および多糖類が挙げられ、好ましくはグルコース、マンノース、フルクトース、リボース、キシロース、アラビノース、ガラクトース、マルトース、セロビオース、ラクトース、スクロース、トレハロース、マルトトリオース等が挙げられる。ここで、多糖類とは広義の糖を意味し、α−シクロデキストリン、セルロースなど自然界に広く存在する物質を含む意味に用いることとする。
【０１２２】
また、これらの糖類の誘導体としては、前記した糖類の還元糖（例えば糖アルコール（一般式ＨＯＣＨ₂（ＣＨＯＨ）_nＣＨ₂ＯＨ（ここでｎ＝２〜５の整数を表す）で表される）、酸化糖（例えば、アルドン酸、ウロン酸など）、アミノ酸、チオ酸などが挙げられる。特に、糖アルコールが好ましく、具体例としてはマルチトール、ソルビットなどが挙げられる。これら糖類の含有量は、インク組成物の０．１〜４０重量％、好ましくは０．５〜３０重量％の範囲が適当である。
【０１２３】
インク組成物としては、その他アルギン酸ナトリウムを含有させてもよい。アルギン酸ナトリウムは、褐藻類にのみ含まれる物質で、主に細胞膜あるいは細胞間隙物質として存在する親水性高分子電解質である。化学的にはβ−１，４結合するＤ−Ｍａｎｎｕｒｏｎｉｃ ａｃｉｄ〔Ｍ〕と、α−１，４結合するＬ−Ｇｕｌｕｒｏｎｉｃ ａｃｉｄ〔Ｇ〕の重合体である。増粘作用、安定化作用、分散作用、ゲル化作用、フィルム形成作用等の効果がある。インクジェット用のインク組成物に添加すると、ｐＨによる粘度変化、塩類による析出、多価陽イオンとのゲル化により、単色の滲み（フェザリング）や異なる色間の滲み（カラーブリード）が改善できる。
【０１２４】
更に、水性記録液のインク組成物中には、防腐防黴剤、ｐＨ調整剤、キレート試薬、防錆剤等を添加することができる。
防腐防黴剤としてはデヒドロ酢酸ナトリウム、ソルビン酸ナトリウム、２−ピリジンチオール−１−オキサイドナトリウム、安息香酸ナトリウム、ペンタクロロフェノールナトリウム等が本発明に使用できる。
【０１２５】
ｐＨ調整剤としては、調合される記録液に悪影響を及ぼさずにｐＨを所望の値に調整できるものであれば、任意の物質を使用することができる。その例として、ジエタノールアミン、トリエタノールアミン等のアミン、水酸化リチウム、水酸化ナトリウム、水酸化カリウム等のアルカリ金属元素の水酸化物、水酸化アンモニウム、第４級アンモニウム水酸化物、第４級ホスホニウム水酸化物、炭酸リチウム、炭酸ナトリウム、炭酸カリウム等のアルカリ金属の炭酸塩等が挙げられる。
【０１２６】
キレート試薬としては、例えば、エチレンジアミン四酢酸ナトリウム、ニトリロ三酢酸ナトリウム、ヒドロキシエチルエチレンジアミン三酢酸ナトリウム、ジエチレントリアミン五酢酸ナトリウム、ウラミル二酢酸ナトリウム等がある。
【０１２７】
防錆剤としては、例えば、酸性亜硫酸塩、チオ硫酸ナトリウム、チオジグリコール酸アンモン、ジイソプロピルアンモニウムニトライト、四硝酸ペンタエリスリトール、ジシクロヘキシルアンモニウムニトライト等がある。
この他、その目的に応じて水溶性紫外線吸収剤を添加することもできる。
【０１２８】
本発明の水性記録液は、インクを記録ヘッドの微細な吐出口より液滴として吐出、飛翔させて記録媒体にカラー画像を形成する、いわゆるインクジェット記録方法にとりわけ好適に用いられるが、水性ペン、水性マーカー、水性ボールペンなどの一般の筆記用具や記録計、ペンプロッター用のインクとして使用できることは云うまでもない。また、本発明の水性記録液は、上記用途に限定されるものではない。
【０１２９】
インクジェット記録方法に使用する場合、インク粘度を所望の値に調節する必要がある。ヘッドの吐出力に依存するものの、一般にインクの粘度は１０ｍＰａ・ｓ以下であることが好ましい。１０ｍＰａ・ｓより大きいとインクジェットによって十分な吐出が行えず、画像不良の問題が発生する場合が多い。本発明の水性記録液を用いて記録を行うのに好適な方法としては、水性記録液に記録信号に対応した熱エネルギーを与え、該熱エネルギーにより液滴を発生させて記録媒体に画像を形成する方法が挙げられる。
【０１３０】
本発明の水性記録液を用いて画像を形成する記録媒体は、パルプ繊維を主成分とし、サイズ度が１０ｓ以上、透気度が５〜５０ｓであることが好ましい。このような記録媒体に対して本発明の水性記録液により印字を行えば、記録媒体の両面にインクジェット記録方法により印字を行っても、裏面の画像により表面の画像の認識を妨げられるようなことはない。ここで云うサイズ度とは、紙のステキヒト・サイズ度試験方法ＪＩＳ Ｐ８１２２−７６に従うものであり、透気度とは、紙及び板紙の透気度試験方法 ＪＩＳ Ｐ８１１７−８０に従うものである。サイズ度が１０ｓより小さいと記録液が裏面まで浸透してしまい裏抜けが発生し、透気度が５ｓより小さい場合も記録液が裏面まで浸透してしまい裏抜けが発生し、５０ｓ以上の場合は印字品質や乾燥性に問題はないが、必要以上に填料を添加しているためにコストが高くなってしまう。また、この記録媒体を電子写真方式の複写機やプリンターに使用した場合、感光体や定着ローラー等に填料が転写し、画像品質の低下や故障の原因になるため、結局はインクジェット専用の紙として使用しなくてはならず消費者に使い分けをさせる必要が生じて負担となる。前記のサイズ度および透気度とすることによって、電子写真用転写紙、印刷用紙、タイプライター用紙、ワイヤードットプリンター用紙、ワードプロセッサー用紙、レター用紙、レポート用紙等種々のノンコートの普通紙と同様に扱うことができ、それに伴い利用者が他の普通紙と分別する手間が無くなる。また、紙を生産する上でも基本的に現有の抄紙機により生産が可能であり、設備投資を最小限に押さえることができる。またこれら他の記録方式の用途にも共通に使用することができる。
【０１３１】
本発明に使用するパルプ繊維の材料としてはインクジェットプロセスに影響無い物であればパルプの種類、処理方法は問わず適宜に使用できる。また非木材パルプ（ケナフ、亜麻、竹、海草等）や古紙パルプを用いてもよいし、これらを主体としたものでもよい。好ましくは、ＬＢＫＰやＮＢＫＰに代表される化学パルプである。これらパルプの抄紙は、一般の普通紙同様公知のサイズ剤、填料、その他抄紙助剤を必要に応じて用い、常法により抄紙される。
【０１３２】
サイズ剤としては、ロジンサイズ、ＡＫＤ、塩化ナトリウム、塩化カリウム、スチレン−マレイン酸コポリマー、第４級アンモニウム塩、アルニケル無水コハク酸、石油樹脂系サイズ、エピクロルヒドン、カチオン澱粉、アクリルアミド等がある。また、填料としてはクレー、炭酸カルシウム、タルク、二酸化チタン、合成シリカ等が挙げられる。更に、紙力増強剤、歩留まり向上剤、定着剤、染料、その他抄紙助剤が添加される。
【０１３３】
本発明者らは、鋭意検討を重ねた結果、本発明の水性記録液をインクジェット記録装置に用いて、記録ヘッドから吐出される１滴あたりの吐出量Ｖ（ｐｌ）が、下記の式（ａ）で示される関係を満足するようにして記録を行うことにより、いわゆる普通紙に対する印字において、裏抜けが少なく、かつべた画像が埋まり良く、白抜けのない良好な画像が得られることを見出した。
【０１３４】
【数３】
２．５×１０⁸／Ｒ^2.6 ≦ Ｖ ≦ ６．０×１０⁸／Ｒ^2.6 ……(ａ)
【０１３５】
（式中、Ｒはパルプ繊維を主成分とし、サイズ度１０ｓ以上、透気度５〜５０ｓである記録媒体に対して記録を行うときの液滴の最大打ち込み密度を示し、単位はｄｏｔ ｐｅｒ ｉｎｃｈ（ｄｐｉ）で表し、液滴吐出量Ｖの単位はｐｉｃｏ ｌｉｔｅｒ（ｐｌ）で表す。）
【０１３６】
シリアル型のインクジェット記録装置の場合、記録ヘッドの走査方向（主走査方向）と紙搬送方向（副走査方向）での打ち込み密度（ｄｐｉ）が異なる場合があるが、この場合は、単位面積当りの打ち込み数を主走査方向と副走査方向とで均等になるように換算した値を用いるのが好ましい。
【０１３７】
前記式（ａ）は、種々の記録液に対して検討してきた結果、実験的に得られた式であるが、式（ａ）の左側は、べた画像を普通紙上に形成したときに白筋などを発生せず、高い画像濃度を得るのに適した関係を示し、式の右側は、過剰な記録液を付着させることによる裏抜け濃度の増大やにじみの発生などを防ぐのに適した関係を示す。いずれの関係も本発明の水性記録液の普通紙に対する優れた浸透特性があって初めて成立する関係である。
【０１３８】
本発明の水性記録液は、浸透性が高く、かつ滲みの無い高品質な画像が得られるため、通常では困難であった高速記録プロセスへの適用が可能である。すなわち、本発明の水性記録液を記録ヘッドの同一あるいは別個の吐出口から複数の液滴として吐出、飛翔させて記録媒体上で画素領域の少なくとも一部が重なるように画像を形成する記録方法において、該記録媒体上で重なりを生じる二つの水性記録液液滴を吐出時間差が０．１２５ミリ秒以下とすることにより、非常に高速記録が可能になる。近年、インクジェットプリンターに間する技術は目覚しい進歩をとげ、印字速度も向上しているものの、ある程度の高画質を維持するためには、隣接する位置関係にあるドットは連続で形成せず、一方が紙中に染み込むまでもう一方の記録液（インク）は着弾させなかった。すなわち、いわゆるマルチパス印字と呼ばれる方法により、印字速度を犠牲にさせながら高画質印字を達成していると云える。本発明の水性記録液は、非常に高い浸透特性を示すため、従来では成し得なかったシングルパスでの高画質印字が可能となった。
【０１３９】
本発明の水性記録液を収容したインクカートリッジおよび該インクカートリッジを具備するインクジェット記録装置について、添付図面を参照して説明するが、以下は構成例のひとつに過ぎず、本発明になんら限定を加えるものではない。
【０１４０】
図１は本発明の水性記録液を収容した記録液収容部を備えたインクカートリッジを搭載するシリアル型インクジェット記録装置の機構部の概略正面図である。
このインクジェット記録装置の機構部は、両側の側板１、２間に主支持ガイドロッド３および従支持ガイドロッド４を略水平な位置関係で横架し、これらの主支持ガイドロッド３および従支持ガイドロッド４でキャリッジユニット５を主走査方向に摺動自在に支持している。キャリッジユニット５には、それぞれイエロー（ｙ）インク、マゼンタ（ｍ）インク、シアン（ｃ）インク、ブラック（ｋ）インクをそれぞれ吐出する４個のヘッド６を、その吐出面（ノズル面）６ａを下方に向けて搭載し、またキャリッジユニット５のヘッド６の上側には４個のヘッド６に各々インクを供給するための各色のインク供給体である４個のインクカートリッジ７ｙ、７ｍ、７ｃ、７ｋを交換可能に搭載している。
【０１４１】
そして、キャリッジユニット５は主走査モータ８で回転される駆動プーリ（駆動タイミングプーリ）９と従動プーリ（アイドラプーリ）１０との間に張装したタイミングベルト１１に連結して、主走査モータ８を駆動制御することによってキャリッジ５、すなわち４個のヘッド６を主走査方向に移動するようにしている。また、側板１、２をつなぐ底板１２上にサブフレーム１３、１４を立設し、このサブフレーム１３、１４間に用紙１６を主走査方向と直交する副走査方向に送るための搬送ローラ１５を回転自在に保持している。そして、サブフレーム１４側方に副走査モータ１７を配設し、この副走査モータ１７の回転を搬送ローラ１５に伝達するために、副走査モータ１７の回転軸に固定したギヤ１８と搬送ローラ１５の軸に固定したギヤ１９とを備えている。
【０１４２】
更に、側板１とサブフレーム１３との間には、ヘッド６の信頼性維持回復機構（以下、「サブシステム」という。）２１を配置している。サブシステム２１は、各ヘッド６の吐出面をキャッピングする４個のキャップ手段２２をホルダ２３で保持し、このホルダ２３をリンク部材２４で揺動可能に保持して、キャリッジユニット５の主走査方向の移動でホルダ２３に設けた係合部２５にキャリッジユニット５が当接することで、キャリッジユニット５の移動に従ってホルダ２３がリフトアップしてキャップ手段２２でインクジェットヘッド６の吐出面６ａをキャッピングし、キャリッジユニット５が印写領域側へ移動することで、キャリッジユニット５の移動に従ってホルダ２３がリフトダウンしてキャップ手段２２がインクジェットヘッド６の吐出面６ａから離れるようにしている。
【０１４３】
なお、キャップ手段２２は、それぞれ吸引チューブ２６を介して吸引ポンプ２７に接続すると共に、大気開放口を形成して、大気開放チューブおよび大気開放バルブを介して大気に連通している。また、吸引ポンプ２７は吸引した廃液を、ドレインチューブ等を介して図示しない廃液貯留槽に排出する。
【０１４４】
更に、ホルダ２３の側方には、インクジェットヘッド６の吐出面６ａをワイピングする繊維部材、発泡部材あるいはゴム等の弾性部材からなるワイピング手段であるワイパブレード２８をブレードアーム２９に取付け、このブレードアーム２９は揺動可能に軸支し、図示しない駆動手段で回動されるカムの回転によって揺動させるようにしている。
【０１４５】
次に、インクカートリッジ７について図２、図３を参照して説明する。ここで、図２は図１の記録装置に装填する前のインクカートリッジの外観斜視図、図３はインクカートリッジの正面断面図である。
インクカートリッジ７は、図３に示すように、カートリッジ本体４１内に所要の色のインクを吸収させたインク吸収体４２を収容してなる。カートリッジ本体４１は、上部に広い開口を有するケース４３の上部開口に上蓋部材４４を接着または溶着して形成したものであり、例えば樹脂成型品からなる。また、インク吸収体４２は、ウレタンフォーム体等の多孔質体からなり、カートリッジ本体４１内に圧縮して挿入した後、インクを吸収させている。
カートリッジ本体４１のケース４３底部には記録ヘッド６へインクを供給するためのインク供給口４５を形成し、このインク供給口４５内周面にはシールリング４６を嵌着している。また、上蓋部材４４には大気開放口４７を形成している。そして、カートリッジ本体４１には、装填前の状態で、インク供給口４５を塞ぐと共に装填時や輸送時などのカートリッジ取扱い時、あるいは真空包装時による幅広側壁に係る圧力でケース４３が圧縮変形されて内部のインクが漏洩することを防止するため、キャップ部材５０を装着している。
【０１４６】
また、大気開放口４７は、図２に示すように、酸素透過率が１００ｍｌ／ｍ²以上のフィルム状シール部材５５を上蓋部材４４に貼着してシールしている。このシール部材５５は大気開放口４７と共にその周囲に形成した複数本の溝４８をもシールする大きさにしている。このように大気開放口４７を酸素透過率が１００ｍｌ／ｍ²以上のシール部材５５でシールすることで、インクカートリッジ７を透気性のないアルミラミネートフィルム等の包装部材を用いて減圧状態で包装することにより、インク充填時やインク吸収体４２とカートリッジ本体４１との間に生じる空間Ａ（図３参照）にある大気のためにインク中に気体が溶存したときでも、シール部材５５を介してインク中の空気が真空度の高いカートリッジ本体４１外の包装部材との間の空間に排出され、インクの脱気度が向上する。
【０１４７】
次に、図４に本発明の記録液を収容した記録液収容部と、記録液液滴を吐出させるためのインクジエットヘッド（記録ヘッド）を備えたインクカートリッジの構成例を示す。以下にインクカートリッジについて説明する。
インクカートリッジ３０は、シリアル型のものであり、インクジェットヘッド６と、このインクジェットヘッド６に供給される記録液（インク）を収容するインクタンク３３と、このインクタンク３３内を密閉する蓋部材とで主要部が構成される。インクジェットヘッド６には、記録液を吐出するための多数のノズル３２が形成されている。記録液はインクタンク３３から、図示しないインク供給管を介して、やはり図示しない共通液室へと導かれ、電極３１より入力される記録装置本体からの電気信号に応じて、ノズル３２より吐出される。このようなタイプのインクカートリッジ３０は、構成上、安価に製造できるタイプのヘッド、いわゆるサーマル方式、バブル方式と呼ばれる熱エネルギーを駆動の動力源とするヘッドに適した構造である。本発明の水性記録液は、バブル方式やサーマル方式等の記録方法において、２，４−ジエチル−１，５−ペンタンジオールを添加することによって、熱素子への濡れ性が改良されるため、少量の添加量でも吐出安定性および周波数安定性が得られ、かつ安全性も高く、非常に適している。
【０１４８】
ここでは、前述のようなシリアル型インクジェット記録装置を説明したが、本発明の水性記録液は、ノズルを千鳥など任意の配列で、目的とする画像の解像度と同じか数分の１程度の密度に集積し、記録媒体の幅以上に配列させた、いわゆるラインヘッドを有する記録装置に適用することも可能である。また、ここで云う記録装置とは、ＰＣやデジカメ用の出力プリンタのみならず、ファックスやスキャナ、電話などと組み合わせた複合的な機能を有する装置であっても構わない。
【０１４９】
【実施例】
以下に本発明の実施例および比較例を示すが、本発明はこれらに限定されるものではない。なお、実施例および比較例に記載の各成分の量（％）は重量基準である。
【０１５０】
実施例１
先ずカーボンブラックを下記の顔料分散液１に示す処方にてビーズミルを用いて分散した。得られた顔料分散液１を下記のインク組成物１に示すインク処方にて混合攪拌した後、ｐＨが８になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液１を得た。
【０１５１】
＜顔料分散液１＞
カーボンブラック （平均粒径１０４ｎｍ） １５ 重量％
スチレン−アクリレート−メタクリル酸ジエ
タノールアミン塩共重合体 ３重量％
イオン交換水 残量
【０１５２】
＜インク組成物１＞
顔料分散液１ ３３．３重量％
グリセリン １０重量％
ジエチレングリコール ６．５重量％
エチレングリコール ３．５重量％
２，４−ジエチル−１，５−ペンタンジオール ５重量％
イオン交換水 残量
【０１５３】
実施例２
下記インク組成物２に示すインク処方にて混合攪拌した後、ｐＨが９になるように水酸化ナトリウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液２を得た。
【０１５４】
＜インク組成物２＞
カルボキシル基結合型カーボンブラック分散液
（固形分１６．４重量％、平均粒径１０８ｎｍ） ３３．３重量％
グリセリン ５重量％
ジエチレングリコール １５重量％
化合物（式（１−１））のナトリウム塩 ０．３重量％
２，４−ジエチル−１，５−ペンタンジオール ２重量％
イオン交換水 残量
【０１５５】
実施例３
下記インク組成物３に示すインク処方にて混合攪拌した後、ｐＨが９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．２μｍのメンブレンフィルターで濾過を行い水性記録液３を得た。
【０１５６】
＜インク組成物３＞
Ｃ．Ｉ．ダイレクトイエロー１４２ ２．０重量％
グリセリン ８重量％
トリエチレングリコール ２０重量％
２，４−ジエチル−１，５−ペンタンジオール ５重量％
２−ピロリドン ２重量％
イオン交換水 残量
【０１５７】
実施例４
実施例１と同様のプロセスで、下記顔料分散液２に示す分散液を処方し、次いでインク組成物４に示すインク処方により混合攪拌した後、ｐＨが９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液４を得た。
【０１５８】
＜顔料分散液２＞
Ｃ．Ｉ．ピグメントブルー１５：３
（平均粒径１３８ｎｍ） １５ 重量％
スチレン−アクリレート−メタクリル酸ジエ
タノールアミン塩共重合体 ３重量％
イオン交換水 残量
【０１５９】
＜インク組成物４＞
顔料分散液２ ３３．３重量％
グリセリン ８重量％
トリエチレングリコール ２０重量％
化合物（式(１−８)）のナトリウム塩 ０．３重量％
２，４−ジエチル−１，５−ペンタンジオール ４重量％
２−ピロリドン ２重量％
イオン交換水 残量
【０１６０】
実施例５
実施例２と同様のプロセスで、下記インク組成物５に示すインク処方により混合攪拌した後、ｐＨ９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液５を得た。
【０１６１】
＜インク組成物５＞
スルホン基結合型カーボンブラック分散液
（固形分１８重量％、平均粒径１３２ｎｍ） ３３重量％
グリセリン ３重量％
ジエチレングリコール ２重量％
化合物（式（１−１３））のリチウム塩 １重量％
２，４−ジエチル−１，５−ペンタンジオール １．５重量％
２−エチル−１，３−ヘキサンジオール ０．５重量％
イオン交換水 残量
【０１６２】
実施例６
実施例１と同様のプロセスで、下記顔料分散液３に示す分散液を処方し、次いでインク組成物６に示すインク処方により混合攪拌した後、ｐＨが９になるように水酸化ナトリウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液６を得た。
【０１６３】
＜顔料分散液３＞
カーボンブラック （平均粒径１０４ｎｍ） １５ 重量％
スチレン−アクリレート−メタクリル酸ジエ
タノールアミン塩共重合体 ３重量％
イオン交換水 残量
【０１６４】
＜インク組成物６＞
顔料分散液３ ３０．０重量％
ダイレクトブラック１６８ ０．５重量％
グリセリン ５重量％
ジエチレングリコール ３０重量％
化合物（式（１−２)）の対イオンに
化合物（式（２−２））を使用した塩 ４重量％
２，４−ジエチル−１，５−ペンタンジオール ３重量％
イオン交換水 残量
【０１６５】
実施例７
実施例１と同様のプロセスで、下記顔料分散液４に示す分散液を処方し、次いでインク組成物７に示すインク処方により混合攪拌した後、ｐＨが８になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液７を得た。
【０１６６】
＜顔料分散液４＞
カーボンブラック（平均粒径５３ｎｍ） １５ 重量％
ナフタレンスルホン酸塩のホルマリン縮合物 ３重量％
イオン交換水 残量
【０１６７】
＜インク組成物７＞
顔料分散液４ ３３．３重量％
エチレングリコール ５重量％
ポリエチレングリコール（分子量２００) ５重量％
ポリオキシエチレン(ｎ＝７)（２級アルキル
エーテル：ノニオン界面活性剤） ０．１重量％
２，４−ジエチル−１，５−ペンタンジオール ３．５重量％
イオン交換水 残量
【０１６８】
実施例８
実施例１と同様のプロセスで、下記顔料分散液５に示す分散液を処方し、次いでインク組成物８に示すインク処方により混合攪拌した後、ｐＨが９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液８を得た。
【０１６９】
＜顔料分散液５＞
カーボンブラック（平均粒径１９６ｎｍ） １５ 重量％
ナフタレンスルホン酸塩のホルマリン縮合物 ３重量％
イオン交換水 残量
【０１７０】
＜インク組成物８＞
顔料分散液５ ３３．３重量％
グリセリン ５重量％
フッ素化アルキルエステル（ノニオン界面活性剤）０．３重量％
２，４−ジエチル−１，５−ペンタンジオール ３重量％
ジエチレングリコールモノブチルエーテル ３重量％
イオン交換水 残量
【０１７１】
実施例９
実施例３と同様のプロセスで、下記インク組成物９に示すインク処方により混合攪拌した後、ｐＨが８になるように水酸化ナトリウム１０％水溶液にて調整した。その後、平均孔径０．２μｍのメンブレンフィルターで濾過を行い水性記録液９を得た。
【０１７２】
＜インク組成物９＞
Ｃ．Ｉ．ダイレクトブラック１６８ ４重量％
グリセリン ５重量％
Ｎ−メチル−２−ピロリドン ５重量％
エチレンオキシド付加ポリプロピレングリコール:ポリ
プロピレングリコール分子量950；ノニオン界面活性剤 ２重量％
２，４−ジエチル−１，５−ペンタンジオール ２．５重量％
２−ピロリドン ２．０重量％
イオン交換水 残量
【０１７３】
実施例１０
実施例３と同様のプロセスで、下記インク組成物１０に示すインク処方により混合攪拌した後、ｐＨが８になるように水酸化ナトリウム１０％水溶液にて調整した。その後、平均孔径０．２μｍのメンブレンフィルターで濾過を行い水性記録液１０を得た。
【０１７４】
＜インク組成物１０＞
Ｃ．Ｉ．ダイレクトレッド２２７ ３重量％
ジエチレングリコール ２０重量％
トリエチレングリコール １０重量％
イオネットＤ−２（アニオン界面活性剤：
三洋化成工業社製） ２．５重量％
２，４−ジエチル−１，５−ペンタンジオール ０．５重量％
２，２，４−トリメチル−１，３−ペンタンジオール １重量％
イオン交換水 残量
【０１７５】
実施例１１
実施例３と同様のプロセスで、下記インク組成物１１に示すインク処方により混合攪拌した後、ｐＨが９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．２μｍのメンブレンフィルターで濾過を行い水性記録液１１を得た。
【０１７６】
＜インク組成物１１＞
Projet FastCyan２（ゼネカ社製） ３重量％
エチレングリコール ２０重量％
ジエチレングリコール ２０重量％
化合物（式（１−５））の対イオンに
化合物（式（２−７））を使用した塩 １重量％
イオネットＤ−２（アニオン界面活性剤;
三洋化成工業社製） １重量％
２，４−ジエチル−１，５−ペンタンジオール ２重量％
２−ピロリドン ０．５重量％
イオン交換水 残量
【０１７７】
比較例１
実施例１と同様のプロセスで、下記顔料分散液６に示す分散液を処方し、次いでインク組成物１２に示すインク処方により混合攪拌した後、ｐＨが９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液１２を得た。
【０１７８】
＜顔料分散液６＞
カーボンブラック（平均粒径１０４ｎｍ） １５ 重量％
スチレン−アクリレート−メタクリル酸ジエ
タノールアミン塩共重合体 ３重量％
イオン交換水 残量
【０１７９】
＜インク組成物１２＞
顔料分散液６ ３３．３重量％
化合物（式（１−１））のナトリウム塩 １重量％
２，４−ジエチル−１，５−ペンタンジオール ２重量％
イオン交換水 残量
【０１８０】
比較例２
実施例２と同様のプロセスで、下記インク組成物１３に示すインク処方により混合攪拌した後、ｐＨ９になるように水酸化ナトリウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液１３を得た。
【０１８１】
＜インク組成物１３＞
黒色顔料（カルボキシル基結合型カーボン
ブラック 平均粒径１０８ｎｍ） ５重量％
グリセリン １０重量％
ジエチレングリコール １０重量％
化合物（式（１−８））のナトリウム塩 ０．３重量％
ジエチレングリコールモノブチルエーテル １重量％
イオン交換水 残量
【０１８２】
比較例３
実施例３と同様のプロセスで、下記インク組成物１４に示すインク処方により混合攪拌した後、ｐＨが９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．２μｍのメンブレンフィルターで濾過を行い水性記録液１４を得た。
【０１８３】
＜インク組成物１４＞
Ｃ．Ｉ．ダイレクトイエロー１４２ ２．０重量％
グリセリン １０重量％
ジエチレングリコール １０重量％
化合物（式（１−１３））のリチウム塩 ４重量％
２−ピロリドン ２重量％
イオン交換水 残量
【０１８４】
比較例４
実施例２と同様のプロセスで、下記インク組成物１５に示すインク処方により混合攪拌した後、ｐＨ９になるように水酸化リチウム１０％水溶液にて調整した。その後、平均孔径０．８μｍのメンブレンフィルターで濾過を行い水性記録液１５を得た。
【０１８５】
＜インク組成物１５＞
スルホン基結合型カーボンブラック分散液
（固形分１８重量％、平均粒径１３２ｎｍ） ３３重量%
グリセリン １０ 重量％
ジエチレングリコール １０ 重量％
化合物（式（１−２））の対イオンに
化合物（式（２−２））を使用した塩 ７重量％
イオン交換水 残量
【０１８６】
上記実施例１〜１１および比較例１〜４で得られた水性記録液１〜１５について下記３種類の記録装置（評価装置）を用いて、画像の鮮明性、画像の乾燥性、裏抜け、擦過性、画像の埋まり、保存性について評価を行った。用いた評価装置は、下記の３台である。各出力に用いた評価装置と各評価項目に対する評価結果を表１に示す。
【０１８７】
評価装置（Ａ）：普通紙に対する液滴の打ち込み密度が、最密の状態で６００×６００ｄｐｉであり、各ノズルから１滴あたりの吐出量２３ｐｌで吐出するよう駆動電圧を調整したピエゾ方式のインクジェットプリンター（ＩＰＳＩＯ ＪＥＴ３００；(株)リコー社製）。
評価装置（Ｂ）：普通紙に対する液滴の打ち込み密度が、最密の状態で２４００×１２００ｄｐｉであり、各ノズルから１滴あたりの吐出量５ｐｌで吐出するサーマル方式のインクジェットプリンター（ＢＪ Ｓ６３０；キャノン(株)社製）。
評価装置（Ｃ）：普通紙に対する液滴の打ち込み密度が、最密の状態で１４４０×７２０ｄｐｉであり、出力画像に合わせて１滴あたりの吐出量を制御することが可能であり、最小の１滴あたりの吐出量が３ｐｌであるピエゾ方式のインクジェットプリンター（ＥＭ−９００Ｃ；セイコーエプソン(株)社製）。
【０１８８】
画像の鮮明性、画像の乾燥性、裏抜け、擦過性、画像の埋まり、保存性の各評価条件と評価の判断は下記によった。
（１）画像の鮮明性：
記録媒体としてＮＢＳリコー社製；マイペーパー（サイズ度１２ｓ，透気度１６ｓ）に印字を行い、乾燥後、画像の滲み、色調、濃度を目視および反射型カラー分光測色濃度計（Ｘ−Ｒｉｔｅ社製）により総合的に判断した。極めて良好を◎、良好を○、普通〜若干劣るを△、不良を×と判定した。
（２）画像の乾燥性：
記録媒体にベタ画像印字後の画像に０．１ｋｇ／ｃｍ²の圧力で濾紙を押しつけインクが濾紙に転写しなくなるまでの時間を測定した。いずれの紙でも３秒以内で乾燥した場合に○、３から２０秒を△、２０秒以上を×と判定した。
（３）裏抜け：
記録媒体に反射型カラー分光測色濃度計（Ｘ−Ｒｉｔｅ社製）で測定した各インク色での濃度が１．０となる様にベタ画像を形成した。この画像を裏面から目視観察し、ベタ画像の着色剤（色材）が裏面まで抜けており、両面印字に使用できないレベルの場合は×、ベタ画像の着色剤（色材）が裏面までは抜けていないが、ベタ画像と白地部分の境界がやや不明確で、両面印字に使用しても支障の無いレベルの場合は△、ベタ画像と白地部分の境界がほとんど不明確で両面印字に使用しても支障の無いレベルの場合は○、ベタ画像と白地部分の境界が完全に不明確で両面印字に使用しても支障の無い場合は◎として判定した。
（４）擦過性：
記録媒体に各インクで形成された画像を、印字３０秒後に指、布、消しゴム、マーキングペンで擦過し、擦過後の様子を目視にて観察し擦過による画像の変化が発生した場合は×とし、発生がなければ○とした。
（５）画像の埋まり：
乾燥後ベタ画像を観察し、拡大して観察してもインクで均一に記録媒体が着色している場合は◎、目視で観察する限りインクで均一に記録媒体が着色している場合は○、目視で地肌が見えるような不均一な着色の場合は×とした。
（６）保存性：
インクをインクジェットプリンターにセットしたまま、６０℃、７日間放置し、その後従来公知のインクジェットプリンターのクリーニング操作1回で復帰可能ならば○、２から５回で復帰可能ならば△、５回でも復帰しなければ×とした。
【０１８９】
【表１】

【０１９０】
実施例１２
次に、実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をゼロックス社製;ゼロックスペーパーＲ(サイズ度８ｓ、透気度２０ｓ)に替え、前記評価装置（Ａ）を用いた以外は実施例２と同様にして、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９１】
実施例１３
実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をＡＵＳＴＲＡＬＩＡＮ ＰＡＰＥＲ社製(オーストラリア); ＲＥＦＬＥＸ（サイズ度２５ｓ、透気度４ｓ）に替えた以外は実施例２と同様に前記評価装置（Ｂ）を用いて、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９２】
実施例１４
実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をＮＢＳリコー社製；ＮＢＳ複写印刷用紙９０Ｋ（サイズ度６０Ｓ、透気度６８ｓ）に替え、前記評価装置（Ａ）を用いた以外は実施例２と同様にして、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９３】
実施例１５
次に、実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をキャノン社製;ＰＢ用紙（サイズ度２１ｓ、透気度８ｓ）に替え、前記評価装置（Ｃ）を用いた以外は実施例２と同様にして、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９４】
実施例１６
次に、実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をＮＢＳリコー社製；ＮＢＳ複写印刷用紙４５Ｋ（サイズ度１１ｓ、透気度４５ｓ）に替え、前記評価装置（Ａ）を用いた以外は実施例２と同様にして、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９５】
実施例１７
次に、実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）を本州製紙社製;やまゆり（サイズ度１２ｓ、透気度２１ｓ）に替え、前記評価装置（Ｃ）を用いた以外は実施例２と同様にして、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９６】
実施例１８
実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をリコー社製;紙源ＰＰＣ用紙タイ−ｆＳ（(サイズ度２２ｓ、透気度１３ｓ)に替えた以外は実施例２と同様に前記評価装置（Ｂ）を用いて、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９７】
実施例１９
実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をゼロックス社製;Ｐ紙（サイズ度２４ｓ、透気度１９ｓ）に替え、前記評価装置（Ｃ）を用いた以外は実施例２と同様にして、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９８】
実施例２０
実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をゼロックス社製;マルチエース（サイズ度２５ｓ、透気度１７ｓ）に替え、前記評価装置（Ａ）を用いた以外は実施例２と同様にして、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０１９９】
実施例２１
実施例２と同様の水性記録液２を用いて、記録媒体（普通紙）をゼロックス社製;Ｘｅｒｏｘ４０２４（サイズ度３２ｓ、透気度２１ｓ）に替えた以外は実施例２と同様に前記評価装置（Ｂ）を用いて、保存性の評価は除いて前記と同じ評価項目について評価した。結果を表２に示す。
【０２００】
【表２】

【０２０１】
表１および表２に示した結果から、本発明のインク組成物からなる水性記録液を用いた場合には、いずれも画像の鮮明性、画像の乾燥性、裏抜け、擦過性、画像の埋まり、保存性に優れており、高速プリントに対しても高乾燥性で、かつ裏抜けのない印字のできることが確認された。
【０２０２】
【発明の効果】
本発明に係る２，４−ジエチル−１，５−ペンタンジオールをインク組成物として含有させることにより、高速印字および両面印字を可能とする裏抜けのない高乾燥性の水性記録液が実現でき、これにより、高速プリント速度に対応したインクジェット記録方法が達成され、該記録液を用いたインクカートリッジおよびインクジエット記録装置が提供される。以下に発明の効果を説明する。
【０２０３】
請求項１に係る発明では、少なくとも、水に溶解または分散する色材と、水と、湿潤剤と、２，４−ジエチル−１，５−ペンタンジオールとを含有するインク組成物とすることにより、色材や紙種によらず浸透性、乾燥性に優れ、かつ滲みが少なく、安全性、保存安定性の優れた水性記録液の提供が可能となる。
【０２０４】
請求項２に係る発明では、２，４−ジエチル−１，５−ペンタンジオールの含有量を０．１〜５重量％とすることにより、浸透特性が高く、画質に優れ、相分離を起さない安定した水性記録液の提供が可能となる。
【０２０５】
請求項３に係る発明では、湿潤剤の含有量を５〜５０重量％とすることにより、目詰まりを起こしにくく、簡単なクリーニング操作で正常な印字状態に回復ができる水性記録液の提供が可能となる。
【０２０６】
請求項４に係る発明では、界面活性剤の含有量を０．０１〜５．０重量％とすることにより、画像濃度の低下、裏抜けを防止し、少量の添加で高い浸透性が得られるため、溶剤臭の少ない水性記録液の提供が可能となる。
【０２０７】
請求項５に係る発明では、少なくともポリオキシエチレンアルキルエーテル酢酸塩を含む界面活性剤を含有することにより、少量の添加で高い浸透性を有する水性記録液の提供が可能となる。
【０２０８】
請求項６に係る発明では、ジエチレングリコール、トリエチレングリコール、グリセリンの少なくとも１つを湿潤剤とすることにより、ノズルの目詰まりを未然に防ぎ、保存安定性と噴射安定性を高めた水性記録液の提供が可能となる。
【０２０９】
請求項７に係る発明では、２−エチル−１，３−ヘキサンジオール、２，２，４−トリメチル−１，３−ペンタンジオールの少なくとも１つを含有することにより、画像濃度低下と裏抜けを防止した低溶剤臭の水性記録液の提供が可能となる。
【０２１０】
請求項８に係る発明では、インク組成物として２−ピロリドンを含有することにより、紙への浸透性は損なわずに、かつ必要以上の紙層内へのインクの浸透を抑えた画像濃度の向上と共に裏抜けを防止した水性記録液の提供が可能となる。
【０２１１】
請求項９に係る発明では、色材を顔料とすることにより、耐水性や耐光性が良好になり、更に高い浸透特性を維持して画像濃度も高く、裏抜けの少ない優れた水性記録液の提供が可能となる。
【０２１２】
請求項１０に係る発明では、顔料の平均粒径を１０ｎｍ〜２００ｎｍとすることにより、保存安定性やインクジェット記録方法における吐出安定性に優れた水性記録液の提供が可能となる。
【０２１３】
請求項１１に係る発明では、カルボキシル基が結合した分散剤により顔料が分散されることにより、滲みの少ない高品位な画像が形成され、かつ印字後の記録媒体の耐水性が向上した水性記録液の提供が可能となる。
【０２１４】
請求項１２に係る発明では、表面に親水基が結合された顔料を用いて水中に分散させることにより、保存安定性、信頼性の極めて高い水性記録液の提供が可能となる。
【０２１５】
請求項１３に係る発明では、顔料表面に結合した親水基をカルボキシル基とすることにより、滲みの少ない高品位な画像が形成され、かつ印字後の記録媒体の耐水性が向上した水性記録液の提供が可能となる。
【０２１６】
請求項１４に係る発明では、本発明の水性記録液を用いることにより、記録媒体上にインクジエット法で高速に画像を形成する記録方法の提供が可能となる。
【０２１７】
請求項１５に係る発明では、本発明の水性記録液を用い、熱エネルギーを作用させて液滴を吐出、飛翔させることにより、熱素子への濡れ性が改良され、吐出安定性、周波数安定性に優れた記録方法の提供が可能となる。
【０２１８】
請求項１６に係る発明では、本発明の水性記録液を用いて画像を形成する記録媒体の主成分をパルプ繊維とし、サイズ度を１０ｓ以上、透気度を５〜５０ｓとすることにより、インクジェット法で両面に印字を行っても、両面の画像の認識が妨げられない記録方法の提供が可能となる。
【０２１９】
請求項１７に係る発明では、本発明の水性記録液を用い、記録ヘッドから吐出される１滴あたりの吐出量と液滴の打ち込み密度との所定の関係を満たして記録することにより、ドット抜けや白筋がなく、高濃度で滲みの少ない高画質画像を得ることのできる記録方法の提供が可能となる。
【０２２０】
請求項１８に係る発明では、本発明の水性記録液を用い、記録媒体上で画素領域が重なりを生じる二つのインクジエット液滴の吐出時間差を０．１２５ミリ秒以下とすることにより、高速で高画質の画像が記録できる記録方法の提供が可能となる。
【０２２１】
請求項１９および請求項２０に係る発明では、記録液を収容した記録液収容部を備えたインクカートリッジの該記録液（インク）として本発明の記録液を用いることにより、高速インクジエットプリント用のインクカートリッジの提供が可能となる。
【０２２２】
請求項２１および請求項２２に係る発明では、インクジェット記録装置に設けられる、記録液を収容した記録液収容部を備えたインクカートリッジの該記録液として本発明の記録液（インク）を用いることにより、高速インクジェット記録装置の提供が可能となる。
【図面の簡単な説明】
【図１】本発明の水性記録液を収容するインクカートリッジを搭載するシリアル型インクジェット記録装置の機構部構成例を示す概略正面図である。
【図２】図１に示す記録装置に装填する前のインクカートリッジの外観斜視図である。
【図３】図２に示すインクカートリッジの正面断面図である。
【図４】図１に示す記録装置に装填する前の記録ヘッドと一体化されたインクカートリッジの外観斜視図である。
【符号の説明】
１ 側板
２ 側板
３ 主支持ガイドロッド
４ 従支持ガイドロッド
５ キャリッジユニット
６ ヘッド
６ａ 吐出面（ノズル面）
７ インクカートリッジ
７ｙ インクカートリッジ
７ｍ インクカートリッジ
７ｃ インクカートリッジ
７ｋ インクカートリッジ
８ 主走査モータ
９ 駆動プーリ（駆動タイミングプーリ）
１０ 従動プーリ（アイドラプーリ）
１１ タイミングベルト
１２ 底板
１３ サブフレーム
１４ サブフレーム
１５ 搬送ローラ
１６ 用紙
１７ 副走査モータ
１８ ギヤ
１９ 固定したギヤ
２１ サブシステム
２２ キャップ手段
２３ ホルダ
２４ リンク部材
２５ 係合部
２６ 吸引チューブ
２７ 吸引ポンプ
２８ ワイパブレード
２９ ブレードアーム
３０ インクカートリッジ
３１ 電極
３２ ノズル
３３ インクタンク
４１ カートリッジ本体
４２ インク吸収体
４３ ケース
４４ 上蓋部材
４５ インク供給口
４６ シールリング
４７ 大気開放口
４８ 溝
５０ キャップ部材
５５ シール部材
Ａ 空間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aqueous recording liquid suitable for ink jet recording to which an on-demand method such as a piezo method or a thermal method or a continuous jetting method such as a charge control method is applied, and particularly exhibits excellent characteristics for non-coated plain paper. The present invention relates to an aqueous recording liquid comprising an ink composition, and further relates to an aqueous recording liquid that is also used for an aqueous writing instrument, a recorder, and a pen plotter. The present invention also relates to a recording method, an ink cartridge, and an ink jet recording apparatus using the aqueous recording liquid.
[0002]
[Prior art]
In recent years, inkjet recording systems have become widespread rapidly due to the advantages of small size, low price, low running cost, low noise, electrophotographic transfer paper, printing paper, typewriter paper, wire dot printer paper, word processor paper. Inkjet printers (inkjet recording apparatuses) capable of printing on various non-coated plain paper such as letter paper and report paper are also on the market.
In these ink jet printers, recording liquids (inks) with improved drying properties have been proposed so that higher quality images can be obtained. However, it is difficult to satisfy all of the color reproducibility of the image, water resistance, light resistance, image drying property, image bleeding and ejection reliability. In particular, in the case of a color printer, even if there is no image quality degradation in the yellow, magenta, and cyan single color printing portions, image quality degradation is likely to occur in the two-color overlapping portion of red, green, and blue. In particular, when drying is performed without using a fixing device, it is known that the drying property is improved by increasing the permeability as disclosed in Japanese Patent Application Laid-Open No. 55-29546. There is a problem that causes.
[0003]
Japanese Patent Publication No. 60-23793 discloses that a dialkylsulfosuccinate as a surfactant improves drying properties and reduces image deterioration, but the pixel diameter is remarkably different depending on the type of paper as a recording medium. In contrast, there is a problem that the image density is significantly reduced. Japanese Examined Patent Publication No. 58-6752 discloses a quick-drying ink with less bleeding by improving the permeability by using a surfactant which is an ethylene oxide adduct having an acetylene bond.
[0004]
However, depending on the colorant (coloring material), for example, an ink using a direct dye such as DBK168 does not improve the drying speed because of a hydrophobic interaction with the coloring material, or an ink using a pigment such as carbon black. However, there is a problem that the pigment is likely to aggregate and the nozzle is clogged and the ink jet direction is likely to be bent.
[0005]
Alternatively, JP-A-8-113739 proposes an ink containing a dye and a water-soluble glycol ether in order to improve the drying rate, and JP-A-10-95941 discloses a pigment, diethylene glycol mono- An ink composition composed of glycol ethers such as n-butyl ether and water has been proposed. However, in order to improve the drying speed, it is necessary to add a large amount of glycol ethers, which is not preferable in terms of ink odor and safety.
[0006]
Japanese Patent Application Laid-Open No. 56-57862 discloses an ink to which a strongly basic substance is added. Although effective with rosin-sized acidic paper, alkyl ketene dimer or alkenyl sulfosuccinic acid is used as a sizing agent. No effect on the paper. In addition, acid paper is not effective in the two-color overlapping portion.
[0007]
Further, JP-A-2-138374 proposes a water-based recording ink comprising a water-soluble dye, water, and a benzyl ether having a specific structure. Among them, in order to further improve the permeability of the ink, an oily substance such as vegetable oil, unsaturated fatty acid, higher alcohol, fatty acid ester, mineral oil, and a solvent having a hydroxyl group in the molecule and hardly soluble or slightly soluble in water. It has been proposed to add 2-ethyl-1,6-hexanediol, diethylene glycol hexyl ether, an ethylene oxide adduct of acetylene glycol (added mole number of 5 or less), ethylene glycol benzyl ether, and the like. However, these inks have safety problems, and oily substances, poorly water-soluble, slightly soluble solvents, benzyl ethers and the like are separated depending on the environmental temperature, which causes a very large problem in stability.
[0008]
Japanese Patent No. 2894568 is a composition containing a dye and a liquid medium, and contains 60% by weight or more of water and 0.2-30% by weight of alkylene glycol having 7 to 10 carbon atoms in the liquid medium. Ink jet inks have been proposed. Preferred examples of the “C7-10 alkylene glycol” include 1,7-heptanediol, 2,6-heptanediol, 2,4-dimethyl-2,4-pentanediol, 3-ethyl-1, 3-pentanediol and the like are exemplified. By including these compounds in the ink, "improving ink bleeding, drying and penetrability on plain paper", "balanced in terms of bleeding and penetrability", "reliable in clogging prevention It is said that it is possible to provide “high-quality” ink. However, in practice, the addition of these exemplified compounds does not sufficiently improve the ink permeability, so that the dryness is low, and depending on the type of paper, bleeding is likely to occur. It was.
[0009]
Japanese Patent No. 2714482 discloses an inkjet ink containing an aliphatic diol compound having a specific structure having at least 6 carbon atoms and having a solubility of at least 4.5 parts by weight in 100 parts by weight of water at 25 ° C. Has been proposed. These diol compounds include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3-propanediol, 2- Methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1,2-diol, etc. Although illustrated, the ink to which any of them was added was not sufficiently penetrable and caused color bleeding and feathering.
[0010]
Accordingly, the present inventors have intensively studied and proposed a water-based ink containing 2-ethyl-1,3-hexanediol and a recording method using the same for the purpose of enhancing permeability (Japanese Patent Laid-Open No. 6-157959). ). The 2-ethyl-1,3-hexanediol contained in the water-based ink of the present invention is not included in the exemplified compound in the above-mentioned Japanese Patent No. 2894568, but a variety of compounds can be obtained by the present inventors. It was discovered after intensive studies from the inside. By containing 2-ethyl-1,3-hexanediol, it is possible to provide an ink composition that satisfies various properties as an inkjet ink, has excellent permeability and drying properties, and has improved image quality degradation. Thus, it was possible to provide a recording method for forming a good image using the ink composition. In addition, a high-frequency driven ejection stability and high safety ink can be provided with a small addition amount of 2-ethyl-1,3-hexanediol.
[0011]
However, due to the rapid technological progress in recent years, the output speed of ink jet printers is steadily increasing, and it is expected that the speed will increase further in the future. Under such circumstances, the ink is required not to cause color bleeding even at higher speed printing, and to dry immediately without rubbing fingers even after rubbing after output. In general, highly dry inks have improved paper penetrability, but have the disadvantages of decreasing the image density and increasing the back-through density due to the colorant (coloring material) penetrating in the thickness direction of the paper. is doing. In particular, it is clear that double-sided printing is indispensable from the viewpoint of so-called paper consumption, which is related to the development of inkjet printers and environmental problems. It can be said that an aqueous recording liquid) is required.
[0012]
As described above, water-based inkjet inks that still satisfy various characteristics as inkjet inks, have excellent penetrability and drying properties regardless of colorant (coloring material) type and paper type, and have improved image quality and back-through. The desire for is still strong. In recent years, in the fields of barcode printing, postmark printing such as mail, etc., a system that reads recorded information by infrared rays or ultraviolet rays, although normally invisible, has been put into practical use. From the viewpoint of environmental pollution, the ink used in these inks has been studied to be water-based, and in order to cope with the high-speed processing essential for such a system, it is water-based but highly permeable water-based recording liquid. Is becoming necessary.
[0013]
[Problems to be solved by the invention]
The present invention has been made in view of such problems, and the object of the present invention is to overcome the problems of the prior art described above, and to achieve high-speed printing corresponding to high-speed printing and double-sided printing that enables double-sided printing. An object of the present invention is to provide a highly dry aqueous recording liquid, an ink jet recording method using the aqueous recording liquid, and an apparatus (ink cartridge, ink jet recording apparatus) using the recording liquid.
[0014]
[Means for Solving the Problems]
The present invention includes at least high-speed printing and double-sided printing by containing, as an ink composition, a colorant that dissolves or disperses in water, water, a wetting agent, and 2,4-diethyl-1,5-pentanediol. And an ink cartridge using the recording liquid simultaneously with the achievement of an inkjet recording method corresponding to a high-speed printing speed by using the aqueous recording liquid. An ink jet recording device was realized.
Hereinafter, the present invention will be specifically described.
[0015]
The invention of claim 1 comprises an ink composition containing at least a colorant that is dissolved or dispersed in water, water, a wetting agent, and 2,4-diethyl-1,5-pentanediol. And an aqueous recording liquid.
[0016]
By using an aqueous recording medium comprising the ink composition of claim 1, an aqueous recording medium having improved image quality, such as excellent penetrability and drying, and less bleeding regardless of the colorant (colorant) or paper type. Liquid is provided. Further, even if the content of 2,4-diethyl-1,5-pentanediol is small, high penetrability is obtained, and an aqueous recording liquid excellent in terms of safety and odor is provided. Further, in addition to the high penetrability and excellent image quality, it is possible to provide high safety, storage stability, and an inexpensive aqueous recording liquid.
[0017]
The invention of claim 2 is characterized in that the content of 2,4-diethyl-1,5-pentanediol is 0.1 to 5% by weight with respect to the total amount of the ink composition. The aqueous recording liquid described in 1.
[0018]
By setting the content of 2,4-diethyl-1,5-pentanediol within the above range, a penetrating property is high, image quality is excellent, phase separation is not caused, and a stable aqueous recording liquid is provided.
[0019]
The invention according to claim 3 is the aqueous recording liquid according to claim 1 or 2, wherein the content of the wetting agent is 5 to 50% by weight with respect to the total amount of the ink composition.
[0020]
By setting the content of the wetting agent in the above range, clogging hardly occurs even when water in the aqueous recording medium made of the ink composition evaporates, and even if clogging occurs, a simple cleaning operation is possible. Provides a recording liquid capable of recovering to a normal printing state.
[0021]
The invention according to claim 4 is characterized in that the ink composition further contains a surfactant in a range of 0.01 to 5% by weight relative to the total amount of the ink composition. The aqueous recording liquid according to any one of the above.
[0022]
By using a combination of surfactants as an ink composition, water-based recording that exhibits synergistic effects and prevents image density reduction and back-through, which was a problem with conventional penetrating inks with improved penetrability Liquid is provided. In addition, it can obtain high penetrability with a small amount of addition compared to an aqueous recording liquid containing each of them alone, so compared with conventional inks that have increased penetrability by adding a large amount of polyhydric alcohol ethers, etc. There are also advantages such as low solvent odor.
[0023]
The invention according to claim 5 is the aqueous recording liquid according to claim 4, characterized in that the surfactant contains at least a polyoxyethylene alkyl ether acetate represented by the following general formula (1).
[0024]
[Chemical formula 2]
R₁-O- (CH₂CH₂O)_m-CH₂COOM (1)
(Wherein R₁Represents an alkyl group having 6 to 14 carbon atoms which may be branched, m represents a natural number of 3 to 12, M represents an alkali metal ion, quaternary ammonium, quaternary phosphonium or alkanolamine. )
[0025]
By containing the above polyoxyethylene alkyl ether acetate as a composition, an image recording is improved, and an aqueous recording liquid capable of obtaining an excellent effect in increasing the image density is provided.
[0026]
The invention according to claim 6 is the aqueous recording liquid according to any one of claims 1 to 5, wherein the wetting agent is a compound selected from at least one of diethylene glycol, triethylene glycol or glycerin. .
[0027]
When an aqueous recording liquid using one or more wetting agents selected from the above compounds in the composition is used in an ink jet recording apparatus, the occurrence of clogging due to water evaporation near the nozzle is prevented, and 2, 4 -Works as a dissolution aid for diethyl-1,5-pentanediol. Thus, an aqueous recording liquid having further improved storage stability and further improved jetting stability is provided.
[0028]
The invention according to claim 7 further includes at least one compound selected from 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol in the ink composition. The aqueous recording liquid according to claim 1, wherein the aqueous recording liquid is a liquid.
[0029]
By using one or more selected from the above-mentioned compounds in combination as a composition, a synergistic effect is exhibited and image density lowering, which is a problem with conventional penetrating inks with improved penetrability, A water-based recording liquid that prevents omission is provided. In addition to the ink containing each of the above compounds alone, high penetrability can be obtained with a small amount of addition, and in comparison with ink that has increased penetrability by adding a large amount of a single polyhydric alcohol ether. An aqueous recording liquid having advantages such as a low solvent odor is provided.
[0030]
The invention according to claim 8 is the aqueous recording liquid according to any one of claims 1 to 7, further comprising 2-pyrrolidone in the ink composition.
[0031]
By containing 2-pyrrolidone, the penetrability of the ink into the paper is not impaired, the ink permeation into the paper layer more than necessary after penetrating the paper is suppressed, and the coloring material is kept near the paper surface. Accordingly, an aqueous recording liquid having an excellent effect of preventing the back-through as well as further improving the image density is provided.
[0032]
The invention according to claim 9 is the aqueous recording liquid according to any one of claims 1 to 8, wherein the color material is a pigment.
[0033]
By using a pigment as a coloring material, water resistance and light resistance are improved, and an excellent aqueous recording liquid with high penetration characteristics and high image density and little show-through is provided.
[0034]
A tenth aspect of the present invention is the aqueous recording liquid according to the ninth aspect, wherein the average particle diameter of the pigment is in the range of 10 nm to 200 nm.
[0035]
Dispersion stability is improved by setting the average particle diameter of the pigment within the above range, and excellent storage stability and ejection stability in the ink jet recording method are provided, and an excellent aqueous recording liquid with less image back-through is provided. Is done.
[0036]
The invention according to claim 11 is an aqueous recording liquid obtained by adding, to an ink composition, a pigment dispersion in which a pigment is dispersed in water with a dispersant, and a carboxyl group is bonded to the dispersant. And an aqueous recording liquid.
[0037]
By using a dispersant to which a carboxyl group is bonded, it is possible to form a very high-quality image with less bleeding, in addition to an even higher image density and a low back-through density. An aqueous recording liquid having improved properties is provided.
[0038]
The invention according to claim 12 is an aqueous recording liquid obtained by adding, to an ink composition, a pigment dispersion in which a pigment is dispersed in water with a dispersant, and the surface of the pigment is modified by bonding with a hydrophilic group. An aqueous recording liquid.
[0039]
By using a pigment whose surface is modified and to which a hydrophilic group is bonded, an aqueous recording liquid having extremely high storage stability and reliability can be provided.
[0040]
A thirteenth aspect of the invention is the aqueous recording liquid according to the twelfth aspect, wherein the hydrophilic group is a carboxyl group.
[0041]
By using a surface-modified pigment in which the hydrophilic group bonded to the pigment is a carboxyl group, it is possible to form an extremely high-quality image with less blurring while further lowering the back-through density at a higher image density. Thus, an aqueous recording liquid in which the water resistance of the recording medium after printing is further improved is provided.
[0042]
According to a fourteenth aspect of the present invention, there is provided a recording method in which an aqueous recording liquid is ejected and ejected as droplets from a discharge port of a recording head to form an image on a recording medium. A recording method comprising the aqueous recording liquid described.
[0043]
Since the aqueous recording liquid comprising the ink composition of the present invention does not undergo phase separation and does not cause aggregation or thickening, it is used in a recording method in which an image is formed on a recording medium by ejecting and flying as droplets from a fine ejection port. Suitable for There is provided a recording method in which printing can be easily performed with a simple cleaning operation without causing clogging even when printing is suspended for a long period of time and the water content of the ink staying in the vicinity of the nozzles of the inkjet head evaporates.
[0044]
According to a fifteenth aspect of the present invention, in the recording method, thermal energy is applied to the aqueous recording liquid, and the liquid is ejected and ejected as droplets from the ejection port of the recording head to form an image on the recording medium. The recording method described in 1.
[0045]
The method of forming an image by applying thermal energy to the aqueous recording liquid is particularly suitable because the wettability to the thermal element is improved, and this provides a recording method having excellent ejection stability and frequency stability. The
[0046]
The invention according to claim 16 is the recording method according to claim 14 or 15, wherein the recording medium has pulp fibers as a main component, the sizing degree is 10 s or more, and the air permeability is 5 to 50 s. .
[0047]
If printing is performed with the aqueous recording liquid of the present invention using a recording medium having pulp fibers as the main component and the above sizing and air permeability, even if printing is performed on both sides of the recording medium by the inkjet recording method, the image on the back side Thus, a low-cost recording method that does not hinder recognition of the surface image is provided.
[0048]
The invention according to claim 17 is a recording method for forming an image on a recording medium by ejecting and flying the aqueous recording liquid according to any one of claims 1 to 13 as droplets from an ejection port of a recording head. The recording method is characterized in that the discharge amount V (pl) per droplet satisfies the following formula (a).
[0049]
[Expression 2]
2.5 × 10⁸/ R^2.6  ≦ V ≦ 6.0 × 10⁸/ R^2.6 ... (a)
[0050]
(In the formula, R represents the maximum drop density when droplets are recorded on a recording medium having pulp fibers as a main component, a sizing degree of 10 s or more and an air permeability of 5 to 50 s, and the unit is dpi (dot per inch), and the unit of the droplet discharge amount V is represented by picolitter (pl).)
[0051]
By using the aqueous recording liquid of the present invention and recording so as to satisfy a predetermined relationship between the ejection amount per droplet ejected from the recording head and the droplet ejection density, dot omission and white streak are recorded. There is provided a recording method capable of obtaining a high-quality image with high density and little blur.
[0052]
According to an eighteenth aspect of the present invention, the aqueous recording liquid according to any one of the first to thirteenth aspects is ejected and ejected as a plurality of droplets from the same or separate ejection openings of the recording head, and at least in the pixel area on the recording medium. In this recording method, an image is formed so that a part thereof overlaps, and a difference in ejection time between two droplets that cause an overlap on the recording medium is 0.125 milliseconds or less.
[0053]
If the high permeability of the aqueous recording liquid of the present invention is utilized, a recording method for recording a high-quality and high-quality image under the above-described high-speed ejection conditions is provided.
[0054]
The invention according to claim 19 is an ink cartridge including a recording liquid storage portion that stores a recording liquid.The recording liquidIs an aqueous recording liquid according to claim 1.
[0055]
When the aqueous recording liquid of the present invention is used as the recording liquid in the above-described configuration including the recording liquid container that contains the recording liquid, high penetrability and high reliability, safety, and excellent image characteristics are possible. An ink cartridge is provided.
[0056]
A twentieth aspect of the invention is an ink cartridge including a recording liquid storage portion that stores a recording liquid and a recording head portion that discharges recording liquid droplets. An ink cartridge comprising the aqueous recording liquid described above.
[0057]
In the above-described configuration including the recording liquid storage section that stores the recording liquid and the recording head section for discharging recording liquid droplets, if the aqueous recording liquid of the present invention is used as the recording liquid, it has high penetration characteristics and high An ink cartridge capable of reliability, safety, and excellent image characteristics is provided.
[0058]
The invention according to claim 21 is an ink jet recording apparatus including an ink cartridge including a recording liquid storage unit storing a recording liquid, and a recording head for discharging recording liquid droplets.The recording liquidIs an aqueous recording liquid according to any one of claims 1 to 13.
[0059]
In the ink jet recording apparatus having the above-described configuration, when the aqueous recording liquid of the present invention is used as a recording liquid, there is a recording apparatus that has high penetrability that can be used for high-speed printing, and that is capable of high reliability, safety, and excellent image characteristics. Provided.
[0060]
The invention of claim 22 is an ink jet recording apparatus equipped with an ink cartridge including a recording liquid storage portion storing a recording liquid and a recording head for discharging recording liquid droplets.The recording liquidIs an aqueous recording liquid according to any one of claims 1 to 13, wherein the inkjet recording apparatus is characterized in that:
[0061]
If the aqueous recording liquid of the present invention is used as the recording liquid in the ink jet recording apparatus having the above-described configuration, it has high penetrability and high reliability, safety, and excellent image characteristics corresponding to high-speed printing similar to claim 21. A possible recording device is provided.
[0062]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
For the purpose of increasing the permeability to paper, the present inventors include 2,4-diethyl-1,5-pentanediol as an ink composition, thereby reducing the surface tension to 50 mN / m or less, and the ink and paper. Not only is it possible to improve the wettability with the surface and increase the penetration speed into the paper, but there is very little image degradation compared to the case where the penetration is increased mainly with surfactants as conventionally known. In addition, when 2,4-diethyl-1,5-pentanediol is used, the colorant can be used because it has the effect that the permeation rate is almost the same regardless of the type of the colorant. However, the present invention is not limited, and it has been found that any coloring material conventionally used in ink jet can be used, and the present invention has been achieved.
[0063]
The 2,4-diethyl-1,5-pentanediol used in the ink composition of the present invention is preferably 0.1 to 5% by weight, more preferably 0.1% to 3% by weight based on the total amount of the ink composition. % By weight. If it is less than 0.1% by weight, the effect of increasing the permeability is small, and if it is added more than 5% by weight, it does not dissolve stably in the ink composition, and there is a problem in storage stability as an aqueous recording liquid and jetting stability in inkjet. Will occur.
[0064]
The surface tension in the present invention is an index indicating the permeability to paper. In particular, the surface tension indicates the dynamic surface tension in a short time of 1 second or less after the surface is formed, and is different from the static surface tension measured by the saturation time. . Any method can be used as long as it can measure a dynamic surface tension of 1 second or less by a conventionally known method described in JP-A-63-131237, etc. In the present invention, the maximum bubble pressure method is used. It was measured. This method is a method in which a dynamic surface tension is obtained by measuring a maximum pressure required to put a capillary tube vertically in a liquid, and send air to release generated bubbles. The surface tension value of the aqueous recording liquid of the present invention is preferably 50 mN / m or less, more preferably 40 mN / m or less, whereby excellent drying properties can be obtained.
[0065]
Also, in order to obtain ejection stability in a recording method such as a so-called bubble method or thermal method, in which thermal energy is applied to ink and ink is ejected as droplets from fine holes, recording is conventionally performed using 2-propanol. There is a method of adding, but instead of this, by adding 2,4-diethyl-1,5-pentanediol, the wettability to the thermal element is improved, and even with a small amount of addition, ejection stability and frequency stability are improved. And the safety issues associated with the use of 2-propanol are also improved.
[0066]
By containing 5% by weight to 50% by weight of a wetting agent for the purpose of preventing clogging due to drying of the ink and improving dissolution stability, the aqueous recording liquid of the present invention is an ejection port of an ink jet head (recording head). Therefore, even if water in the ink evaporates, not only can clogging hardly occur, but normal printing can be performed, and even if clogging occurs, it can be restored to a normal printing state by a simple cleaning operation. I found it.
[0067]
Further, 2,4-diethyl-1,5-pentanediol and a wetting agent, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol and / or a surfactant And a combination of the above and the like, it has been found that a synergistic effect is exhibited and a decrease in image density and a back-through, which have been problems with conventional penetrating inks with improved penetrability, are prevented. Further, when combined with the ink containing each of the above components alone, high permeability can be obtained with a small amount of addition. For this reason, there is an advantage that the solvent odor is less than that of the ink in which a large amount of ethers of polyhydric alcohols and the like are added to increase the permeability.
[0068]
The aqueous recording liquid of the present invention uses water as a liquid medium. In order to make the ink have desired physical properties, to prevent clogging due to drying of the ink, or to improve the dissolution stability of the ink, etc. For the purpose described above, the following water-soluble organic solvents can be used as the wetting agent.
[0069]
For example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 1,2,4 -Polyhydric alcohols such as butanetriol, 1,2,3-butanetriol, petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl Ethers, polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether, ethylene glycol monophenyl ether Polyhydric alcohol aryl ethers such as ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, nitrogen-containing heterocyclic compounds such as γ-butyrolactone, amides such as formamide, N-methylformamide, N, N-dimethylformamide, amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine, Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol, propylene carbonate, ethylene carbonate and the like. These solvents are used alone or in combination with water.
[0070]
The amount of these wetting agents added to the ink composition is 5 to 50% by weight, preferably 8 to 30% by weight, as described above. If it is less than 5% by weight, the storage stability of the ink and the jetting stability in the ink jet are inferior, and if it is added more than 50% by weight, the jetting stability in the ink jet is inferior due to an increase in viscosity.
[0071]
Among the wetting agents, particularly containing diethylene glycol, triethylene glycol and / or glycerin causes clogging due to drying of the ink, that is, prevention of poor ejection characteristics due to water evaporation and dissolution of the aqueous recording liquid comprising the ink composition of the present invention An excellent effect is obtained in improving the stability. Further, it has been found that when 2-pyrrolidone is added to the ink composition, an excellent effect can be obtained in improving the image density and preventing back-through without impairing the permeability of the ink to the paper. This is because the inclusion of 2-pyrrolidone makes it easier for the ink to wet and spread on the paper surface, and the penetration of the paper into the thickness direction of the paper is relatively suppressed, so that the color material tends to stay near the paper surface. Presumed to be. The amount of 2-pyrrolidone added is preferably 0.05 wt% to 8 wt%, more preferably 0.5 wt% to 4 wt%.
[0072]
Examples of the surfactant used in the present invention include anionic surfactants such as dodecylbenzene sulfonate, polyoxyethylene alkyl ether acetate, laurate, ammonium salt of polyoxyethylene alkyl ether sulfate, quaternary Cationic surfactants such as ammonium salts, amphoteric surfactants such as imidazoline derivatives, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, Nonionic surface activity such as polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, ethylene oxide additive of acetylene alcohol Agents.
[0073]
The addition amount of the surfactant in the ink composition is 0.01 wt% to 5 wt%, preferably 0.5 wt% to 3 wt%. If it is less than 0.01% by weight, there is no effect, and if it is more than 5% by weight, the permeability to the recording medium is unnecessarily high, and there is a problem in that the image density is lowered and show-through occurs. In particular, a surfactant of an anionic surfactant is preferable, and polyoxyethylene alkyl ether acetate represented by the following general formula (1) is more preferable. When this is used, the embedding of the image is improved, and an excellent effect is obtained in increasing the image density.
[0074]
[Chemical 3]
R₁-O- (CH₂CH₂O)_m-CH₂COOM (1)
[0075]
(Wherein R₁Represents an alkyl group having 6 to 14 carbon atoms which may be branched, m represents a natural number of 3 to 12, M represents an alkali metal ion, quaternary ammonium, quaternary phosphonium or alkanolamine. )
[0076]
Specific examples of the compound represented by the general formula (1) are shown in the following formulas (1-1) to (1-14) in a free acid form, but are not limited thereto.
[0077]
[Formula 4]

[0078]
The said compound may be used independently and may mix and use multiple things. As a commercially available surfactant containing this compound as a main component, ECTD3NEX (in the general formula (1), R₁: Tridecyl group, m: 3, M: Na), ECT3 (R₁: Tridecyl group, m: 3, M: H), ECTD6NEX (R₁: Tridecyl group, m: 6, M: Na) and other surfactants can also be used.
[0079]
By using an alkali metal ion, quaternary ammonium, quaternary phosphonium, or alkanolamine as a counter ion of the compound represented by the general formula (1), excellent dissolution stability is exhibited. Further, it is more preferable to use sodium, lithium and / or quaternary ammonium, quaternary phosphonium, or alkanolamine cation represented by the following general formula (2) as a counter ion because the dissolution stability is further increased.
[0080]
[Chemical formula 5]

[0081]
Wherein Y represents nitrogen or phosphorus, R₁~ R_FourEach represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, or a halogenated alkyl group. )
[0082]
For example, when a lithium salt is used as the counter ion of the general formula (1), it is carried out by adding lithium hydroxide, and the quaternary ammonium, phosphonium, alkanolamine cation, etc. of the general formula (2) are obtained. When using, specifically, it is carried out by adding a hydroxide represented by the following formulas (2-1) to (2-9).
[0083]
[Chemical 6]

[0084]
[Chemical 7]

[0085]
[Chemical 8]

[0086]
[Chemical 9]

[0087]
Embedded image

[0088]
Embedded image

[0089]
Embedded image

[0090]
Embedded image

[0091]
Embedded image

[0092]
In addition to 2,4-diethyl-1,5-pentanediol, penetrants added for the purpose of adjusting the surface tension include diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, Alkyl and aryl ethers of polyhydric alcohols such as diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether, fluorosurfactants, ethanol, 2-propanol, etc. Although lower alcohols are mentioned, diethylene glycol monobutyl ether or triethylene glycol monobutyl is particularly preferred. It is an ether.
[0093]
The color material used in the present invention may be any of a pigment and / or a dye. As the water-soluble dye used as the coloring material, dyes classified into acid dyes, direct dyes, basic dyes, reactive dyes, and food dyes in the color index are used. These dyes may be used as a mixture of a plurality of types, or may be used as a mixture with other pigments such as pigments as necessary. These coloring materials are added within a range not impeding the effects of the present invention.
Specific examples of these dyes are listed below.
[0094]
Examples of acid dyes and food dyes include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142; C.I. I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106, 111, 114, 115, 134, 186, 249, 254 289; C.I. I. Acid Blue 9, 29, 45, 92, 249; I. Acid Black 1, 2, 7, 24, 26, 94; I. Food Yellow 2, 3, 4; C.I. I. Food Red 7, 9, 14; C.I. I. Food Black 1, 2
Etc.
[0095]
As a direct dye, C.I. I. Direct yellow 1, 12, 24, 26, 33, 44, 50, 120, 132, 142, 144, 86; I. Direct red 1, 4, 9, 13, 17, 20, 28, 31, 39, 80, 81, 83, 89, 225, 227; I. Direct orange 26, 29, 62, 102; I. Direct Blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199, 202; C.I. I. Direct black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, 168, 171
Etc.
[0096]
As a basic dye, C.I. I. Basic Yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 465, 67 70, 73, 77, 87, 91; C.I. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70 73, 78, 82, 102, 104, 109, 112; I. Basic Blue 1, 3, 5, 7, 9, 21, 22, 26, 35, 41, 45, 47, 54, 62, 65, 66, 67, 69, 75, 77, 78, 89, 92, 93 105, 117, 120, 122, 124, 129, 137, 141, 147, 155; I. Basic Black 2, 8
Etc.
[0097]
As reactive dyes, C.I. I. Reactive Black 3, 4, 7, 11, 12, 17; C.I. I. Reactive Yellow 1, 5, 11, 13, 14, 20, 21, 22, 25, 40, 47, 51, 55, 65, 67; C.I. I. Reactive Red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96, 97; C.I. I. Reactive Blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95
Etc.
[0098]
As the dye, acidic dyes and direct dyes can be preferably used, and excellent effects can be obtained in terms of improving the dissolution stability of the aqueous recording liquid of the present invention, color tone, water resistance, and light resistance. The addition amount of the dye as the coloring material in the ink composition is preferably 0.5 to 25% by weight, more preferably 2 to 15% by weight.
[0099]
An inorganic pigment and an organic pigment can be used as the pigment without any particular limitation. Compared to dyes, they are not dissolved in the ink but dispersed as particles, so even inks with the same penetration characteristics are less likely to penetrate deep into the paper, which results in high image density and good image quality with little show-through Can be obtained.
[0100]
Examples of inorganic pigments include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, or carbon black produced by a known method such as contact method, furnace method, thermal method, etc. Can be used. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (eg, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments). , Dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (eg basic dye chelates, acid dye chelates), nitro pigments, nitroso pigments or aniline black . Among these pigments, those having particularly good affinity with water are preferably used. The addition amount of the pigment as the coloring material in the ink composition is preferably 0.5 to 25% by weight, more preferably 2 to 15% by weight.
[0101]
Specific examples of pigments preferably used in the present invention are shown below.
For black, carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, channel black, or metal such as copper, iron (CI Pigment Black 11), titanium oxide And organic pigments such as aniline black (CI Pigment Black 1). Further, for color use, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 81, 83, 95, 97, 98, 100, 101, 104, 408 109, 110, 117, 120, 138, 150, 153; I. Pigment orange 5, 13, 16, 17, 36, 43, 51; C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219; I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38; I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3 (phthalocyanine blue), 16, 17: 1, 56, 60, 63; I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
[0102]
The black pigment used as the color material is preferably carbon black. For black ink, carbon black is excellent in color tone, water resistance, light repellency, dispersion stability, and inexpensive. Other pigments (for example, carbon) that can be dispersed in water by treating the surface with a resin or the like, and pigments (for example, carbon) that have a functional group such as a sulfone group or a carboxyl group added to the surface. The processed pigment etc. which were made can be used. Further, the pigment may be included in the microcapsule so that the pigment can be dispersed in water.
[0103]
According to a preferred embodiment of the present invention, the pigment in the ink composition preferably has an average particle size in the range of 10 nm to 200 nm. The average particle diameter here refers to the amount of change in the frequency (frequency of light) of light (backscattered light) returning from the particle when the Brownian motion particles in the recording liquid are irradiated with laser light. This refers to a value of 50% cumulative volume measured by using a dynamic light scattering method (Doppler scattering light analysis) for determining the particle diameter.
[0104]
When the colorant is a pigment, water resistance and light resistance are improved, and further, it is possible to prevent a breakthrough (hereinafter simply referred to as a breakthrough) in which ink is removed from the recording medium layer and oozes out to the back surface. Since the pigment is not dissolved and dispersed in the aqueous recording liquid composed of the ink composition, the pigment is less likely to enter the recording medium than the liquid component of the ink when printed by inkjet, and is close to the surface of the recording medium. Since it stays, the drying property is fast and it is possible to prevent the see-through. When the average particle size is 10 nm or less, the effect of preventing the back-through is small, and when it is 200 nm or more, the dispersion stability of the aqueous recording liquid is poor, and the particle size may increase due to aggregation during storage, resulting in poor discharge stability.
[0105]
The pigment is preferably dispersed in an aqueous medium in advance using a dispersant to form a pigment dispersion, and the dispersion is added as an ink composition. As a preferable dispersing agent, a known dispersing agent used for preparing a conventionally known pigment dispersion can be used. Examples of the polymer dispersant include the following.
[0106]
As a hydrophilic polymer, naturally occurring gum arabic, tragan gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch and other seaweed polymers, alginic acid, carrageenan, agar, etc. Animal polymers such as gelatin, casein, albumin and collagen, microbial polymers such as xanthene gum and dextran, and fibrin polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose in the semi-synthetic system, Examples thereof include starch polymers such as sodium starch glycolate and sodium starch phosphate, and seaweed polymers such as sodium alginate and propylene glycol alginate.
[0107]
In the pure synthetic system, polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer , Styrene-methacrylic acid copolymer, styrene-acrylic acid-alkyl acrylate copolymer, styrene-methacrylic acid-alkyl acrylate copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene- α-methylstyrene-acrylic acid copolymer-alkyl acrylate ester copolymer, styrene-maleic acid copolymer, vinylnaphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene Copolymer, vinyl acetate-maleic acid ester copolymer Examples thereof include a polymer, a vinyl acetate-crotonic acid copolymer, and a vinyl acetate-acrylic acid copolymer.
[0108]
The copolymer preferably has a weight average molecular weight of 3,000 to 50,000, more preferably 5,000 to 30,000, and most preferably 7,000 to 15,000. The addition amount of the polymer dispersant may be appropriately added within the range in which the pigment is stably dispersed and the other effects of the present invention are not lost. The ratio of pigment to dispersant is preferably in the range of 1: 0.06 to 1: 3, more preferably in the range of 1: 0.125 to 1: 3.
[0109]
It is also possible to use a water-soluble surfactant as a pigment dispersant. In this case, the increase in the ink viscosity with respect to the amount used is smaller than when the polymer dispersant is used, and it is easy to obtain a pigment-based ink having good ejection characteristics when used in the ink jet recording method.
[0110]
Examples of water-soluble surfactants used as pigment dispersants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. The amount of surfactant added as a dispersant May be added as long as the pigment is stably dispersed and the other effects of the present invention are not lost. Specific examples are shown below.
[0111]
For example, anionic surfactants include alkyl allyl or alkyl naphthalene sulfonate, alkyl phosphate, alkyl sulfate, alkyl sulfonate, alkyl ether sulfate, alkyl sulfosuccinate, alkyl ester sulfate, alkyl benzene sulfonic acid Salt, alkyl diphenyl ether disulfonate, alkyl aryl ether phosphate, alkyl aryl ether sulfate, alkyl aryl ether ester sulfate, olefin sulfonate, alkane olefin sulfonate, polyoxyethylene alkyl ether phosphate, polyoxy Ethylene alkyl ether sulfate, ether carboxylate, sulfosuccinate, α-sulfo fatty acid ester, fatty acid salt, higher fatty acid and amino acid condensate, naphthenic acid And the like.
[0112]
Examples of the cationic surfactant include alkylamine salts, dialkylamine salts, aliphatic amine salts, benzalkonium salts, quaternary ammonium salts, alkylpyridinium salts, imidazolinium salts, sulfonium salts, phosphonium salts, and the like. .
[0113]
Further, nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene glycol ester, polyoxyethylene fatty acid amide, polyoxyethylene fatty acid ester, polyoxyethylene Ethylene polyoxypropylene glycol, glycerin ester, sorbitan ester, sucrose ester, glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol ester polyoxyethylene ether, fatty acid alkanolamide, amine oxide, polyoxyethylene Alkylamine, glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbi Emissions fatty acid esters, polyoxyethylene sorbitol fatty acid esters, alkyl (poly) Gurikokishido like.
[0114]
Alternatively, amphoteric surfactants include imidazoline derivatives such as imidazolinium betaine, dimethylalkyl lauryl betaine, alkyl glycine, alkyl di (aminoethyl) glycine, and the like.
[0115]
The dispersant in the ink composition is preferably one having a carboxyl group bonded thereto. When the carboxyl group is bonded to the dispersant, not only the dispersion stability is improved, but also high-quality print quality is obtained and the water resistance of the recording medium after printing is further improved. Furthermore, the effect of preventing the above-described back-through can be obtained. In particular, when a pigment dispersed with a dispersant having a carboxyl group bonded thereto and 2,4-diethyl-1,5-pentanediol are used in combination, a recording medium having a relatively high size such as plain paper is used. Even in the case of printing, a sufficient drying speed can be obtained, and the effect that there is little show-through is obtained. This is because the dissociation constant of the carboxylic acid is small compared to other acid groups, so that after the pigment adheres to the recording medium, the pH value of the ink decreases or the polyvalent metal such as calcium present near the recording medium surface. It is presumed that the solubility of the dispersant itself decreases due to interaction with ions and the like, and the dispersant itself and the pigment aggregate.
[0116]
Another more preferable form includes a form in which the pigment in the ink composition is surface-modified so that the carboxyl group is directly bonded to the pigment and is dispersed in water in this state. In this case, since the surface of the pigment is modified and the carboxyl group is bonded, not only the dispersion stability is improved, but also high-quality print quality is obtained by the same action as described above and the water resistance of the recording medium after printing is obtained. More improved. In addition, because this form of ink has excellent redispersibility after drying, printing is paused for a long period of time, and simple cleaning is possible without causing clogging even when water in the ink near the nozzles of the inkjet head (recording head) evaporates. Good printing can be easily performed by operation.
[0117]
Further, it can be applied to barcode printing and postmark printing using an invisible recording liquid that is rapidly spreading in recent years. In this case, instead of ordinary dyes and pigments, an infrared absorber or an ultraviolet absorber that does not absorb in the visible region and absorbs infrared rays or ultraviolet rays is added to the ink composition.
The aqueous recording liquid of the present invention contains a coloring material, water, a wetting agent, 2,4-diethyl-1,5-pentanediol as main components, and a surfactant and the like can be appropriately added. Additives can be added. For example, a resin emulsion may be added to the aqueous recording liquid of the present invention.
[0118]
The resin emulsion that can be used in the present invention means an emulsion in which the continuous phase is water and the dispersed phase is the following resin component. That is, examples of the resin component of the dispersed phase include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, and styrene resins. This resin is preferably a polymer having both a hydrophilic part and a hydrophobic part. The particle size of these resin components is not particularly limited as long as an emulsion is formed, but is preferably about 150 nm or less, more preferably about 5 to 100 nm. These resin emulsions can be obtained by mixing resin particles with water, optionally with a surfactant.
[0119]
Examples of commercially available resin emulsions include microgel E-1002, E-5002 (styrene-acrylic resin emulsion: manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion: manufactured by Dainippon Ink & Chemicals, Inc.), Boncoat 5454 (styrene-acrylic resin emulsion: manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion: manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion: Seiden Chemical) Etc.).
[0120]
The ink composition in the aqueous recording liquid of the present invention preferably contains a resin emulsion such that the resin component is 0.1 to 40% by weight of the ink composition, more preferably in the range of 1 to 25% by weight. is there. The resin emulsion has the property of thickening and aggregating, and has the effect of suppressing the penetration of the color material component in the paper depth direction and further promoting the fixing to the recording medium. In addition, depending on the type of resin emulsion, a film is formed on the recording medium, which has the effect of improving the scratch resistance of the printed matter.
[0121]
In addition, the ink composition may contain sugar for the purpose of suppressing water evaporation in the aqueous recording liquid. Examples of saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, Examples include lactose, sucrose, trehalose, maltotriose and the like. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose.
[0122]
Examples of derivatives of these saccharides include reducing sugars of the aforementioned saccharides (for example, sugar alcohol (general formula HOCH₂(CHOH)_nCH₂OH (represented by an integer of n = 2 to 5), oxidized sugar (for example, aldonic acid, uronic acid, etc.), amino acid, thioic acid and the like. In particular, sugar alcohols are preferred, and specific examples include maltitol, sorbit and the like. The content of these saccharides is suitably 0.1 to 40% by weight, preferably 0.5 to 30% by weight of the ink composition.
[0123]
In addition, the ink composition may contain sodium alginate. Sodium alginate is a substance contained only in brown algae, and is a hydrophilic polymer electrolyte that exists mainly as a cell membrane or intercellular substance. Chemically, it is a polymer of D-Mannuronic acid [M] that bonds β-1,4 and L-Guluronic acid [G] that bonds α-1,4. There are effects such as thickening action, stabilizing action, dispersing action, gelling action, film forming action and the like. When added to an ink composition for ink jetting, it is possible to improve single color bleeding (feathering) and bleeding between different colors (color bleeding) due to viscosity change due to pH, precipitation due to salts, and gelation with polyvalent cations.
[0124]
Furthermore, antiseptic / antifungal agents, pH adjusters, chelating reagents, rust inhibitors and the like can be added to the ink composition of the aqueous recording liquid.
As antiseptic / antifungal agents, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used in the present invention.
[0125]
As the pH adjuster, any substance can be used as long as the pH can be adjusted to a desired value without adversely affecting the recording liquid to be prepared. Examples thereof include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, and quaternary phosphonium. Examples thereof include carbonates of alkali metals such as hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate.
[0126]
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.
[0127]
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.
In addition, a water-soluble ultraviolet absorber can be added depending on the purpose.
[0128]
The aqueous recording liquid of the present invention is particularly preferably used in a so-called inkjet recording method in which a color image is formed on a recording medium by ejecting and flying ink as droplets from a fine ejection port of a recording head. Needless to say, it can be used as ink for general writing instruments such as water-based markers and water-based ballpoint pens, recorders, and pen plotters. Further, the aqueous recording liquid of the present invention is not limited to the above uses.
[0129]
When used in an ink jet recording method, it is necessary to adjust the ink viscosity to a desired value. In general, the viscosity of the ink is preferably 10 mPa · s or less although it depends on the ejection force of the head. When the pressure is higher than 10 mPa · s, sufficient ejection cannot be performed by ink jet, and a problem of image defect often occurs. As a suitable method for recording using the aqueous recording liquid of the present invention, thermal energy corresponding to a recording signal is applied to the aqueous recording liquid, and droplets are generated by the thermal energy to form an image on a recording medium. The method of doing is mentioned.
[0130]
The recording medium on which an image is formed using the aqueous recording liquid of the present invention preferably contains pulp fibers as a main component, has a sizing degree of 10 s or more, and an air permeability of 5 to 50 s. If such a recording medium is printed with the aqueous recording liquid of the present invention, even if printing is performed on both sides of the recording medium by the ink jet recording method, recognition of the front image is hindered by the back side image. There is no. The sizing degree referred to here conforms to the paper sticky sizing degree test method JIS P8122-76, and the air permeability refers to the paper and paperboard air permeability test method JIS P8117-80. When the sizing degree is less than 10 s, the recording liquid penetrates to the back surface, resulting in a back-through, and even when the air permeability is less than 5 s, the recording liquid penetrates to the back surface and a back-through occurs, and when it is 50 s or more. Although there is no problem in the print quality and drying property, since the filler is added more than necessary, the cost becomes high. In addition, when this recording medium is used in an electrophotographic copying machine or printer, the filler is transferred to a photoconductor or a fixing roller, etc., resulting in deterioration of image quality or failure. It must be used, and it becomes a burden because it is necessary for consumers to use them properly. By using the above sizing and air permeability, it is handled in the same way as various non-coated plain papers such as electrophotographic transfer paper, printing paper, typewriter paper, wire dot printer paper, word processor paper, letter paper, report paper, etc. Accordingly, there is no need for the user to separate from other plain paper. In addition, the paper can be basically produced by the existing paper machine, and the capital investment can be minimized. It can also be used in common for these other recording methods.
[0131]
The pulp fiber material used in the present invention can be appropriately used regardless of the type of pulp and the treatment method as long as it does not affect the inkjet process. Further, non-wood pulp (such as kenaf, flax, bamboo, seaweed, etc.) or waste paper pulp may be used, or those based on these may be used. Preferably, it is a chemical pulp represented by LBKP and NBKP. Paper making of these pulps is carried out in the usual manner using known sizing agents, fillers, and other paper making aids as required, as with ordinary plain paper.
[0132]
Examples of the sizing agent include rosin size, AKD, sodium chloride, potassium chloride, styrene-maleic acid copolymer, quaternary ammonium salt, arnique succinic anhydride, petroleum resin-based size, epichlorohydrone, cationic starch, acrylamide and the like. Examples of the filler include clay, calcium carbonate, talc, titanium dioxide, and synthetic silica. Further, a paper strength enhancer, a yield improver, a fixing agent, a dye, and other paper making aids are added.
[0133]
As a result of intensive studies, the present inventors have used the aqueous recording liquid of the present invention in an ink jet recording apparatus, and the ejection amount V (pl) per droplet ejected from the recording head is expressed by the following formula (a It has been found that by recording so as to satisfy the relationship shown in (2), it is possible to obtain a good image with less back-through, solid images, and no white spots in so-called plain paper printing. .
[0134]
[Equation 3]
2.5 × 10⁸/ R^2.6  ≦ V ≦ 6.0 × 10⁸/ R^2.6  ...... (a)
[0135]
(In the formula, R represents the maximum drop density when droplets are recorded on a recording medium having pulp fibers as a main component, a sizing degree of 10 s or more and an air permeability of 5 to 50 s, and the unit is dot per inch. (It is expressed by (dpi), and the unit of the droplet discharge amount V is expressed by pico liter (pl).)
[0136]
In the case of a serial type ink jet recording apparatus, the driving density (dpi) in the scanning direction (main scanning direction) of the recording head and the paper transport direction (sub-scanning direction) may be different. It is preferable to use a value obtained by converting the number of drivings so as to be equal in the main scanning direction and the sub-scanning direction.
[0137]
The equation (a) is an equation obtained experimentally as a result of studies on various recording liquids. The left side of the equation (a) shows white lines when a solid image is formed on plain paper. The right side of the equation shows a relationship that is suitable for preventing an increase in the back-through density and the occurrence of bleeding due to the excessive recording liquid adhering to the image. Indicates. Both of these relationships are established only when the aqueous recording liquid of the present invention has excellent penetration characteristics with respect to plain paper.
[0138]
The aqueous recording liquid of the present invention can be applied to a high-speed recording process, which has been difficult in general, because it has high penetrability and a high-quality image without bleeding. That is, in the recording method for forming an image so that at least a part of the pixel region overlaps on the recording medium by ejecting and flying the aqueous recording liquid of the present invention as a plurality of droplets from the same or different ejection ports of the recording head. By setting the difference in ejection time between two aqueous recording liquid droplets that overlap each other on the recording medium to be 0.125 milliseconds or less, very high speed recording can be performed. In recent years, the technology related to inkjet printers has made remarkable progress and the printing speed has improved, but in order to maintain a certain level of high image quality, dots in adjacent positional relations have not been formed continuously. The other recording liquid (ink) was not landed until it soaked into the paper. That is, it can be said that high-quality printing is achieved while sacrificing the printing speed by a method called multi-pass printing. Since the aqueous recording liquid of the present invention exhibits very high penetrability, high-quality printing in a single pass, which has not been possible in the past, has become possible.
[0139]
An ink cartridge containing the aqueous recording liquid of the present invention and an ink jet recording apparatus including the ink cartridge will be described with reference to the accompanying drawings. However, the following is only one example of the configuration, and the present invention is not limited in any way. It is not a thing.
[0140]
FIG. 1 is a schematic front view of a mechanism part of a serial type ink jet recording apparatus equipped with an ink cartridge equipped with a recording liquid storage part storing an aqueous recording liquid of the present invention.
The mechanism part of the ink jet recording apparatus lays the main support guide rod 3 and the sub support guide rod 4 between the side plates 1 and 2 on both sides in a substantially horizontal positional relationship, and the main support guide rod 3 and the sub support guide. The carriage 4 is supported by the rod 4 so as to be slidable in the main scanning direction. The carriage unit 5 has four heads 6 for discharging yellow (y) ink, magenta (m) ink, cyan (c) ink, and black (k) ink, respectively, and an ejection surface (nozzle surface) 6a. The four ink cartridges 7y, 7m, 7c, and 7k, which are ink supply bodies for each color, are mounted downward and are supplied to the four heads 6 on the upper side of the heads 6 of the carriage unit 5. Is installed in a replaceable manner.
[0141]
The carriage unit 5 is connected to a timing belt 11 stretched between a driving pulley (drive timing pulley) 9 and a driven pulley (idler pulley) 10 that are rotated by the main scanning motor 8, and the main scanning motor 8 is connected to the carriage unit 5. By controlling the driving, the carriage 5, that is, the four heads 6 are moved in the main scanning direction. Further, sub frames 13 and 14 are erected on the bottom plate 12 connecting the side plates 1 and 2, and a conveying roller 15 for feeding the paper 16 in the sub scanning direction orthogonal to the main scanning direction is provided between the sub frames 13 and 14. Holds freely. A sub-scanning motor 17 is disposed on the side of the sub-frame 14, and a gear 18 fixed to the rotation shaft of the sub-scanning motor 17 and the transporting roller 15 in order to transmit the rotation of the sub-scanning motor 17 to the transporting roller 15. And a gear 19 fixed to the shaft.
[0142]
Further, a reliability maintenance / recovery mechanism (hereinafter referred to as “subsystem”) 21 of the head 6 is disposed between the side plate 1 and the subframe 13. The sub-system 21 holds four cap means 22 for capping the ejection surface of each head 6 by a holder 23, and this holder 23 is held by a link member 24 so as to be swingable so that the carriage unit 5 can move in the main scanning direction. When the carriage unit 5 comes into contact with the engaging portion 25 provided on the holder 23 by the movement of the holder 23, the holder 23 is lifted up according to the movement of the carriage unit 5 and the ejection surface 6a of the inkjet head 6 is capped by the cap means 22, As the carriage unit 5 moves to the printing region side, the holder 23 is lifted down as the carriage unit 5 moves, so that the cap means 22 moves away from the ejection surface 6 a of the inkjet head 6.
[0143]
The cap means 22 is connected to the suction pump 27 via the suction tube 26, forms an atmosphere opening, and communicates with the atmosphere via the atmosphere opening tube and the atmosphere opening valve. The suction pump 27 discharges the sucked waste liquid to a waste liquid storage tank (not shown) through a drain tube or the like.
[0144]
Further, on the side of the holder 23, a wiper blade 28, which is a wiping means made of an elastic member such as a fiber member, a foam member, or rubber, for wiping the discharge surface 6a of the inkjet head 6 is attached to a blade arm 29. Reference numeral 29 is pivotally supported so that it can be swung by rotation of a cam that is rotated by a driving means (not shown).
[0145]
Next, the ink cartridge 7 will be described with reference to FIGS. Here, FIG. 2 is an external perspective view of the ink cartridge before being loaded into the recording apparatus of FIG. 1, and FIG. 3 is a front sectional view of the ink cartridge.
As shown in FIG. 3, the ink cartridge 7 includes an ink absorber 42 that absorbs ink of a required color in a cartridge main body 41. The cartridge body 41 is formed by adhering or welding an upper lid member 44 to an upper opening of a case 43 having a wide opening at the upper portion, and is made of, for example, a resin molded product. The ink absorber 42 is made of a porous material such as a urethane foam, and after being compressed and inserted into the cartridge body 41, the ink is absorbed.
An ink supply port 45 for supplying ink to the recording head 6 is formed at the bottom of the case 43 of the cartridge body 41, and a seal ring 46 is fitted on the inner peripheral surface of the ink supply port 45. The upper lid member 44 has an air opening 47 formed therein. In the cartridge body 41, the case 43 is compressed and deformed by the pressure applied to the wide side wall when the ink supply port 45 is closed and the cartridge is handled during loading or transportation, or during vacuum packaging, in the state before loading. In order to prevent internal ink from leaking, a cap member 50 is attached.
[0146]
Further, as shown in FIG. 2, the air opening 47 has an oxygen permeability of 100 ml / m.²The film-like sealing member 55 described above is adhered to the upper lid member 44 for sealing. The seal member 55 is sized to seal the plurality of grooves 48 formed around the air release port 47 as well as the atmosphere. In this way, the oxygen release rate of the atmosphere opening 47 is 100 ml / m.²By sealing with the sealing member 55 described above, the ink cartridge 7 is packaged under reduced pressure using a packaging member such as a non-permeable aluminum laminate film, so that the ink absorber 42 and the cartridge main body 41 Even when the gas is dissolved in the ink due to the atmosphere in the space A (see FIG. 3) generated between the air and the packaging member outside the cartridge main body 41 having a high degree of vacuum, the air in the ink passes through the seal member 55. The ink is discharged into the space between the ink and the degree of deaeration of the ink is improved.
[0147]
Next, FIG. 4 shows an example of the configuration of an ink cartridge provided with a recording liquid storage portion that stores the recording liquid of the present invention and an ink jet head (recording head) for discharging recording liquid droplets. The ink cartridge will be described below.
The ink cartridge 30 is of a serial type, and includes an inkjet head 6, an ink tank 33 that stores a recording liquid (ink) supplied to the inkjet head 6, and a lid member that seals the inside of the ink tank 33. The main part is composed. The inkjet head 6 is formed with a large number of nozzles 32 for discharging a recording liquid. The recording liquid is guided from the ink tank 33 to a common liquid chamber (not shown) through an ink supply pipe (not shown), and is discharged from the nozzle 32 in accordance with an electric signal from the recording apparatus main body input from the electrode 31. The This type of ink cartridge 30 has a structure suitable for a head that can be manufactured at a low cost, that is, a head that uses thermal energy called a thermal method or bubble method as a driving power source. The aqueous recording liquid of the present invention has a small amount because the wettability to the thermal element is improved by adding 2,4-diethyl-1,5-pentanediol in a recording method such as bubble method or thermal method. Even with the added amount, the ejection stability and the frequency stability can be obtained, and the safety is high, which is very suitable.
[0148]
Here, the serial type ink jet recording apparatus as described above has been described, but the aqueous recording liquid of the present invention has a density equal to or about a fraction of the target image resolution in an arbitrary arrangement such as a staggered nozzle. It is also possible to apply the present invention to a recording apparatus having a so-called line head, which is integrated in an array and arranged more than the width of the recording medium. In addition, the recording apparatus referred to here may be an apparatus having a complex function in combination with a fax machine, a scanner, a telephone, or the like, as well as an output printer for a PC or a digital camera.
[0149]
【Example】
Examples and Comparative Examples of the present invention are shown below, but the present invention is not limited to these. In addition, the amount (%) of each component described in Examples and Comparative Examples is based on weight.
[0150]
Example 1
First, carbon black was dispersed using a bead mill according to the formulation shown in the following pigment dispersion 1. The obtained pigment dispersion 1 was mixed and stirred with the ink formulation shown in the ink composition 1 below, and then adjusted with a 10% aqueous solution of lithium hydroxide so that the pH was 8. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and obtained the aqueous recording liquid 1.
[0151]
<Pigment dispersion 1>
Carbon black (average particle size 104nm) 15% by weight
Styrene-acrylate-methacrylic acid die
Tanolamine salt copolymer 3% by weight
Ion exchange water
[0152]
<Ink composition 1>
Pigment dispersion 1 33.3% by weight
Glycerin 10% by weight
Diethylene glycol 6.5% by weight
Ethylene glycol 3.5% by weight
2,4-diethyl-1,5-pentanediol 5% by weight
Ion exchange water
[0153]
Example 2
After mixing and stirring with the ink formulation shown in ink composition 2 below, the pH was adjusted to 9 with a 10% aqueous solution of sodium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 2.
[0154]
<Ink composition 2>
Carboxyl group-bonded carbon black dispersion
(Solid content 16.4 wt%, average particle size 108 nm) 33.3% wt
Glycerin 5% by weight
Diethylene glycol 15% by weight
Sodium salt of compound (formula (1-1)) 0.3% by weight
2,4-diethyl-1,5-pentanediol 2% by weight
Ion exchange water
[0155]
Example 3
After mixing and stirring with the ink formulation shown in ink composition 3 below, the pH was adjusted to 9 with a 10% aqueous solution of lithium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.2 μm was performed to obtain an aqueous recording liquid 3.
[0156]
<Ink composition 3>
C. I. Direct Yellow 142 2.0% by weight
Glycerin 8% by weight
Triethylene glycol 20% by weight
2,4-diethyl-1,5-pentanediol 5% by weight
2-pyrrolidone 2% by weight
Ion exchange water
[0157]
Example 4
In the same process as in Example 1, a dispersion shown in Pigment Dispersion 2 below was formulated, then mixed and stirred according to the ink formulation shown in Ink Composition 4, and then a 10% aqueous solution of lithium hydroxide so that the pH was 9 Adjusted. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 4.
[0158]
<Pigment dispersion 2>
C. I. Pigment Blue 15: 3
(Average particle size 138 nm) 15 wt%
Styrene-acrylate-methacrylic acid die
Tanolamine salt copolymer 3% by weight
Ion exchange water
[0159]
<Ink composition 4>
Pigment dispersion 2 33.3% by weight
Glycerin 8% by weight
Triethylene glycol 20% by weight
Sodium salt of compound (formula (1-8)) 0.3% by weight
2,4-diethyl-1,5-pentanediol 4% by weight
2-pyrrolidone 2% by weight
Ion exchange water
[0160]
Example 5
In the same process as in Example 2, the mixture was stirred with the ink formulation shown in Ink Composition 5 below, and then adjusted to pH 9 with a 10% aqueous solution of lithium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 5.
[0161]
<Ink composition 5>
Sulfon group-bonded carbon black dispersion
(Solid content 18 wt%, average particle size 132 nm) 33 wt%
Glycerin 3% by weight
Diethylene glycol 2% by weight
Lithium salt of compound (formula (1-13)) 1% by weight
2,4-diethyl-1,5-pentanediol 1.5% by weight
2-ethyl-1,3-hexanediol 0.5% by weight
Ion exchange water
[0162]
Example 6
In the same process as in Example 1, a dispersion shown in the following pigment dispersion 3 was formulated, then mixed and stirred according to the ink formulation shown in ink composition 6, and then a 10% aqueous solution of sodium hydroxide so that the pH was 9 Adjusted. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 6.
[0163]
<Pigment dispersion 3>
Carbon black (average particle size 104nm) 15% by weight
Styrene-acrylate-methacrylic acid die
Tanolamine salt copolymer 3% by weight
Ion exchange water
[0164]
<Ink composition 6>
Pigment dispersion 3 30.0% by weight
Direct Black 168 0.5% by weight
Glycerin 5% by weight
Diethylene glycol 30% by weight
As a counter ion of the compound (formula (1-2))
4% by weight of salt using compound (formula (2-2))
2,4-diethyl-1,5-pentanediol 3% by weight
Ion exchange water
[0165]
Example 7
In the same process as in Example 1, a dispersion shown in the following pigment dispersion 4 was formulated, then mixed and stirred according to the ink formulation shown in ink composition 7, and then a 10% aqueous solution of lithium hydroxide so that the pH was 8 Adjusted. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 7.
[0166]
<Pigment dispersion 4>
Carbon black (average particle size 53 nm) 15% by weight
3% by weight of formalin condensate of naphthalene sulfonate
Ion exchange water
[0167]
<Ink composition 7>
Pigment dispersion 4 33.3% by weight
Ethylene glycol 5% by weight
Polyethylene glycol (molecular weight 200) 5% by weight
Polyoxyethylene (n = 7) (secondary alkyl
Ether: Nonionic surfactant) 0.1% by weight
2,4-diethyl-1,5-pentanediol 3.5% by weight
Ion exchange water
[0168]
Example 8
In the same process as in Example 1, a dispersion shown in the following pigment dispersion 5 was formulated, then mixed and stirred according to the ink formulation shown in ink composition 8, and then a 10% aqueous solution of lithium hydroxide so that the pH was 9 Adjusted. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 8.
[0169]
<Pigment dispersion 5>
Carbon black (average particle size 196 nm) 15% by weight
3% by weight of formalin condensate of naphthalene sulfonate
Ion exchange water
[0170]
<Ink composition 8>
Pigment dispersion 5 33.3% by weight
Glycerin 5% by weight
Fluorinated alkyl ester (nonionic surfactant) 0.3% by weight
2,4-diethyl-1,5-pentanediol 3% by weight
Diethylene glycol monobutyl ether 3% by weight
Ion exchange water
[0171]
Example 9
In the same process as in Example 3, after mixing and stirring according to the ink formulation shown in Ink Composition 9 below, the pH was adjusted to 8 with a 10% aqueous solution of sodium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.2 μm was performed to obtain an aqueous recording liquid 9.
[0172]
<Ink composition 9>
C. I. Direct Black 168 4% by weight
Glycerin 5% by weight
N-methyl-2-pyrrolidone 5% by weight
Polyethylene glycol with ethylene oxide addition: Poly
Propylene glycol molecular weight 950; Nonionic surfactant 2% by weight
2,4-diethyl-1,5-pentanediol 2.5% by weight
2-pyrrolidone 2.0% by weight
Ion exchange water
[0173]
Example 10
In the same process as in Example 3, after mixing and stirring according to the ink formulation shown in Ink Composition 10 below, the pH was adjusted to 8 with a 10% aqueous solution of sodium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.2 μm was performed to obtain an aqueous recording liquid 10.
[0174]
<Ink composition 10>
C. I. Direct Red 227 3% by weight
Diethylene glycol 20% by weight
10% by weight of triethylene glycol
Ionette D-2 (anionic surfactant:
Sanyo Chemical Industries) 2.5% by weight
2,4-diethyl-1,5-pentanediol 0.5% by weight
2,2,4-Trimethyl-1,3-pentanediol 1% by weight
Ion exchange water
[0175]
Example 11
In the same process as in Example 3, after mixing and stirring according to the ink formulation shown in Ink Composition 11 below, the pH was adjusted to 9 with a 10% aqueous solution of lithium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.2 μm was performed to obtain an aqueous recording liquid 11.
[0176]
<Ink composition 11>
Projet FastCyan2 (manufactured by Zeneca) 3% by weight
20% ethylene glycol
Diethylene glycol 20% by weight
As a counter ion of the compound (formula (1-5))
1% by weight of salt using compound (formula (2-7))
Ionette D-2 (anionic surfactant;
Sanyo Chemical Industries) 1% by weight
2,4-diethyl-1,5-pentanediol 2% by weight
2-pyrrolidone 0.5% by weight
Ion exchange water
[0177]
Comparative Example 1
In the same process as in Example 1, a dispersion shown in the following pigment dispersion 6 was formulated, then mixed and stirred according to the ink formulation shown in the ink composition 12, and then a 10% aqueous solution of lithium hydroxide so that the pH was 9 Adjusted. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 12.
[0178]
<Pigment dispersion 6>
Carbon black (average particle size 104nm) 15% by weight
Styrene-acrylate-methacrylic acid die
Tanolamine salt copolymer 3% by weight
Ion exchange water
[0179]
<Ink composition 12>
Pigment dispersion 6 33.3% by weight
1% by weight of sodium salt of compound (formula (1-1))
2,4-diethyl-1,5-pentanediol 2% by weight
Ion exchange water
[0180]
Comparative Example 2
In the same process as in Example 2, the mixture was mixed and stirred according to the ink formulation shown in the following ink composition 13, and then adjusted to pH 9 with a 10% aqueous solution of sodium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 13.
[0181]
<Ink composition 13>
Black pigment (carboxyl-bonded carbon)
Black Average particle size 108nm) 5% by weight
Glycerin 10% by weight
Diethylene glycol 10% by weight
Sodium salt of compound (formula (1-8)) 0.3% by weight
Diethylene glycol monobutyl ether 1% by weight
Ion exchange water
[0182]
Comparative Example 3
In the same process as in Example 3, after mixing and stirring according to the ink formulation shown in Ink Composition 14 below, the pH was adjusted to 9 with a 10% aqueous solution of lithium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.2 μm was performed to obtain an aqueous recording liquid 14.
[0183]
<Ink composition 14>
C. I. Direct Yellow 142 2.0% by weight
Glycerin 10% by weight
Diethylene glycol 10% by weight
Lithium salt of compound (formula (1-13)) 4% by weight
2-pyrrolidone 2% by weight
Ion exchange water
[0184]
Comparative Example 4
In the same process as in Example 2, after mixing and stirring according to the ink formulation shown in Ink Composition 15 below, the pH was adjusted to 9 with a 10% aqueous solution of lithium hydroxide. Thereafter, filtration with a membrane filter having an average pore diameter of 0.8 μm was performed to obtain an aqueous recording liquid 15.
[0185]
<Ink composition 15>
Sulfon group-bonded carbon black dispersion
(Solid content 18 wt%, average particle size 132 nm) 33 wt%
Glycerin 10% by weight
Diethylene glycol 10% by weight
As a counter ion of the compound (formula (1-2))
7% by weight of salt using compound (formula (2-2))
Ion exchange water
[0186]
Using the following three types of recording devices (evaluation devices) for the aqueous recording liquids 1 to 15 obtained in Examples 1 to 11 and Comparative Examples 1 to 4, the image sharpness, the image drying property, the showthrough, Evaluations were made on scratchability, image embedding, and storage stability. The following three evaluation devices were used. Table 1 shows the evaluation device used for each output and the evaluation results for each evaluation item.
[0187]
Evaluation device (A): Piezo-type inkjet in which the density of droplets on plain paper is 600 × 600 dpi in the most dense state, and the drive voltage is adjusted so that each nozzle discharges at a discharge amount of 23 pl. Printer (IPSIO JET300; manufactured by Ricoh Co., Ltd.).
Evaluation device (B): Thermal ink jet printer (BJ S630; Canon) that ejects droplets onto plain paper at a close density of 2400 × 1200 dpi and ejects from each nozzle at an ejection amount of 5 pl (Made by Co., Ltd.).
Evaluation device (C): The density of droplets to be placed on plain paper is 1440 × 720 dpi in the most dense state, and the discharge amount per droplet can be controlled in accordance with the output image. Piezo-type ink jet printer (EM-900C; manufactured by Seiko Epson Corporation) having a discharge amount per droplet of 3 pl.
[0188]
The evaluation conditions and evaluation judgments for image sharpness, image dryness, back-through, scratching, image embedding, and storage stability were as follows.
(1) Image clarity:
As a recording medium, manufactured by NBS Ricoh Co., Ltd .; printed on my paper (size: 12 s, air permeability: 16 s); Comprehensive judgment). Very good was judged as ◎, good as ○, normal to slightly inferior Δ, and poor as x.
(2) Image dryness:
0.1kg / cm on the solid image printed on the recording medium²The pressure paper was pressed against the filter paper, and the time until the ink no longer transferred to the filter paper was measured. When any paper was dried within 3 seconds, it was judged as ◯ for 3 to 20 seconds, and x for 20 seconds or more.
(3) Betrayal:
A solid image was formed on the recording medium so that the density of each ink color measured with a reflective color spectrocolorimetric densitometer (manufactured by X-Rite) was 1.0. When this image is visually observed from the back side, the solid image colorant (coloring material) is missing up to the back side, and the level cannot be used for double-sided printing, x, the solid image colorant (coloring material) is missing up to the back side. However, if the boundary between the solid image and the white background is slightly unclear, and it is at a level that does not interfere with the use of double-sided printing, the boundary between the solid image and the white background is almost unclear and used for double-sided printing. Even when the level was satisfactory, it was judged as ◯, and when the solid image and the white background were completely unclear and judged to be satisfactory even when used for double-sided printing, it was judged as ◎.
(4) Abrasion:
The image formed with each ink on the recording medium is rubbed with a finger, cloth, eraser, or marking pen 30 seconds after printing. If there was no occurrence, it was rated as ○.
(5) Image filling:
Observe the solid image after drying, ◎ if the recording medium is uniformly colored with ink even if it is enlarged and observed, ◯ if the recording medium is uniformly colored with ink as long as visually observed, In the case of non-uniform coloring that allows the background to be seen with the naked eye, X was marked.
(6) Preservability:
Leave the ink in the ink jet printer for 7 days at 60 ° C, and then return to the previous well-known ink jet printer with a single cleaning operation. Otherwise, it was marked as x.
[0189]
[Table 1]

[0190]
Example 12
Next, using the same aqueous recording liquid 2 as in Example 2, the recording medium (plain paper) was changed to Xerox Corporation; Xerox Paper R (size 8s, air permeability 20s), and the evaluation device (A) In the same manner as in Example 2 except that was used, the same evaluation items as described above were evaluated except for storage stability evaluation. The results are shown in Table 2.
[0191]
Example 13
Similar to Example 2 except that the recording medium (plain paper) was changed to AUSTRALIAN PAPER (Australia); REFLEX (size 25 s, air permeability 4 s) using the same aqueous recording liquid 2 as in Example 2. Using the evaluation device (B), the same evaluation items as described above were evaluated except for storage stability evaluation. The results are shown in Table 2.
[0192]
Example 14
Using the same aqueous recording liquid 2 as in Example 2, the recording medium (plain paper) was changed to NBS Ricoh Co .; NBS copy printing paper 90K (size 60S, air permeability 68s), and the evaluation device (A) In the same manner as in Example 2 except that was used, the same evaluation items as described above were evaluated except for storage stability evaluation. The results are shown in Table 2.
[0193]
Example 15
Next, using the same aqueous recording liquid 2 as in Example 2, the recording medium (plain paper) was changed to Canon paper; PB paper (size 21 s, air permeability 8 s), and the evaluation device (C) was Except for the use, the same evaluation items as described above were evaluated in the same manner as in Example 2 except for the evaluation of storage stability. The results are shown in Table 2.
[0194]
Example 16
Next, using the same aqueous recording liquid 2 as in Example 2, the recording medium (plain paper) was changed to NBS Ricoh Co .; NBS copy printing paper 45K (size 11s, air permeability 45s), and the evaluation apparatus Except for using (A), the same evaluation items as described above were evaluated in the same manner as in Example 2 except for the evaluation of storage stability. The results are shown in Table 2.
[0195]
Example 17
Next, using the same aqueous recording liquid 2 as in Example 2, the recording medium (plain paper) was changed to Honshu Paper Co .; Yamayuri (size 12s, air permeability 21s), and the evaluation device (C) was changed to The same evaluation items as described above were evaluated except for the storage stability in the same manner as in Example 2 except that they were used. The results are shown in Table 2.
[0196]
Example 18
The same example as in Example 2 except that the recording medium (plain paper) was changed to a paper source PPC paper tie-fS ((size 22 s, air permeability 13 s), using a recording medium (plain paper) manufactured by Ricoh. Using the evaluation device (B), the same evaluation items as described above were evaluated except for the storage stability evaluation, and the results are shown in Table 2.
[0197]
Example 19
Using the same aqueous recording liquid 2 as in Example 2 except that the recording medium (plain paper) was changed to P paper (size 24 s, air permeability 19 s), and the evaluation device (C) was used. In the same manner as in Example 2, the same evaluation items as described above were evaluated except for the evaluation of storage stability. The results are shown in Table 2.
[0198]
Example 20
Using the same aqueous recording liquid 2 as in Example 2, the recording medium (plain paper) was made by Xerox Corporation; Multi-Ace (size 25s, air permeability 17s) was used, except that the evaluation device (A) was used. In the same manner as in Example 2, the same evaluation items as described above were evaluated except for the evaluation of storage stability. The results are shown in Table 2.
[0199]
Example 21
The evaluation apparatus was the same as in Example 2 except that the recording medium (plain paper) was changed to Xerox 4024 (size 32 s, air permeability 21 s) using the same aqueous recording liquid 2 as in Example 2. Using (B), the same evaluation items as described above were evaluated except for the evaluation of storage stability. The results are shown in Table 2.
[0200]
[Table 2]

[0201]
From the results shown in Table 1 and Table 2, when the aqueous recording liquid comprising the ink composition of the present invention is used, the image sharpness, the image drying property, the back-through, the scratching property, and the image filling are all observed. It was confirmed that it was excellent in storability, was highly dry for high-speed printing, and could be printed without show-through.
[0202]
【The invention's effect】
By including the 2,4-diethyl-1,5-pentanediol according to the present invention as an ink composition, it is possible to realize a highly dry aqueous recording liquid without back-through that enables high-speed printing and double-sided printing, Thereby, an ink jet recording method corresponding to a high-speed printing speed is achieved, and an ink cartridge and an ink jet recording apparatus using the recording liquid are provided. The effects of the invention will be described below.
[0203]
According to the first aspect of the present invention, an ink composition containing at least a colorant that is dissolved or dispersed in water, water, a wetting agent, and 2,4-diethyl-1,5-pentanediol is used. Therefore, it is possible to provide an aqueous recording liquid that is excellent in permeability and drying properties, has little bleeding, and has excellent safety and storage stability regardless of the color material and paper type.
[0204]
In the invention according to claim 2, by setting the content of 2,4-diethyl-1,5-pentanediol to 0.1 to 5% by weight, the penetration property is high, the image quality is excellent, and phase separation is caused. It is possible to provide a stable aqueous recording liquid.
[0205]
In the invention according to claim 3, by setting the content of the wetting agent to 5 to 50% by weight, it is possible to provide an aqueous recording liquid that is less likely to be clogged and can be restored to a normal printing state by a simple cleaning operation. It becomes.
[0206]
In the invention according to claim 4, by setting the content of the surfactant to 0.01 to 5.0% by weight, the image density is prevented from being lowered and the back-through is prevented, and high permeability can be obtained by adding a small amount. Therefore, it is possible to provide an aqueous recording liquid with little solvent odor.
[0207]
In the invention according to claim 5, by containing a surfactant containing at least polyoxyethylene alkyl ether acetate, it is possible to provide an aqueous recording liquid having high permeability with a small addition.
[0208]
In the invention according to claim 6, by using at least one of diethylene glycol, triethylene glycol, and glycerin as a wetting agent, clogging of the nozzle is prevented in advance, and the aqueous recording liquid having improved storage stability and jetting stability. Provision is possible.
[0209]
In the invention according to claim 7, by containing at least one of 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol, image density reduction and show-through are prevented. It is possible to provide an aqueous recording liquid having a low solvent odor that is prevented.
[0210]
In the invention according to claim 8, by containing 2-pyrrolidone as the ink composition, the image density is improved without impairing the permeability to the paper and suppressing the penetration of the ink into the paper layer more than necessary. At the same time, it is possible to provide an aqueous recording liquid that prevents the show-through.
[0211]
In the invention according to claim 9, by using a pigment as a coloring material, water resistance and light resistance are improved, and further, high penetrability is maintained, image density is high, and an excellent aqueous recording liquid with less show-through is obtained. Provision is possible.
[0212]
In the invention according to claim 10, by setting the average particle diameter of the pigment to 10 nm to 200 nm, it is possible to provide an aqueous recording liquid having excellent storage stability and ejection stability in the ink jet recording method.
[0213]
In the invention according to claim 11, the aqueous recording liquid in which the pigment is dispersed by the dispersant having a carboxyl group bonded thereto, thereby forming a high-quality image with less bleeding and improving the water resistance of the recording medium after printing. Can be provided.
[0214]
In the invention according to claim 12, it is possible to provide an aqueous recording liquid having extremely high storage stability and reliability by dispersing in water using a pigment having a hydrophilic group bonded to the surface.
[0215]
In the invention according to claim 13, by using a hydrophilic group bonded to the pigment surface as a carboxyl group, a high-quality image with less bleeding is formed and the water resistance of the recording medium after printing is improved. Provision is possible.
[0216]
In the invention according to claim 14, by using the aqueous recording liquid of the present invention, it is possible to provide a recording method for forming an image on a recording medium at a high speed by an ink jet method.
[0217]
In the invention according to claim 15, by using the aqueous recording liquid of the present invention and applying thermal energy to eject and eject droplets, wettability to the thermal element is improved, and ejection stability and frequency stability are improved. It is possible to provide an excellent recording method.
[0218]
In the invention according to claim 16, the main component of the recording medium for forming an image using the aqueous recording liquid of the present invention is pulp fiber, the sizing degree is 10 s or more, and the air permeability is 5 to 50 s. It is possible to provide a recording method that does not hinder recognition of images on both sides even if printing is performed on both sides by the method.
[0219]
According to the seventeenth aspect of the present invention, by using the aqueous recording liquid of the present invention and performing recording while satisfying a predetermined relationship between the ejection amount per droplet ejected from the recording head and the droplet ejection density, In addition, it is possible to provide a recording method that can obtain a high-quality image with high density and little bleeding without white stripes.
[0220]
In the invention according to claim 18, the aqueous recording liquid of the present invention is used, and the difference in ejection time between two ink jet droplets in which the pixel areas overlap on the recording medium is set to 0.125 milliseconds or less at high speed. A recording method capable of recording a high-quality image can be provided.
[0221]
In the inventions according to claim 19 and claim 20, by using the recording liquid of the present invention as the recording liquid (ink) of an ink cartridge provided with a recording liquid storage portion that stores the recording liquid, the ink for high-speed ink jet printing can be used. An ink cartridge can be provided.
[0222]
In the inventions according to claims 21 and 22, by using the recording liquid (ink) of the present invention as the recording liquid of an ink cartridge provided in an ink jet recording apparatus and provided with a recording liquid storage part that stores the recording liquid. It is possible to provide a high-speed ink jet recording apparatus.
[Brief description of the drawings]
FIG. 1 is a schematic front view showing a structural example of a mechanism part of a serial type ink jet recording apparatus equipped with an ink cartridge containing an aqueous recording liquid of the present invention.
FIG. 2 is an external perspective view of an ink cartridge before being loaded into the recording apparatus shown in FIG.
FIG. 3 is a front sectional view of the ink cartridge shown in FIG.
4 is an external perspective view of an ink cartridge integrated with a recording head before being loaded into the recording apparatus shown in FIG.
[Explanation of symbols]
1 Side plate
2 Side plate
3 Main support guide rod
4 Sub-support guide rod
5 Carriage unit
6 heads
6a Discharge surface (nozzle surface)
7 Ink cartridge
7y ink cartridge
7m ink cartridge
7c Ink cartridge
7k ink cartridge
8 Main scanning motor
9 Drive pulley (drive timing pulley)
10 Driven pulley (idler pulley)
11 Timing belt
12 Bottom plate
13 subframes
14 subframes
15 Transport roller
16 paper
17 Sub-scanning motor
18 gear
19 Fixed gear
21 Subsystem
22 Cap means
23 Holder
24 Link member
25 engaging part
26 Suction tube
27 Suction pump
28 Wiper blade
29 Blade Arm
30 Ink cartridge
31 electrodes
32 nozzles
33 Ink tank
41 Cartridge body
42 Ink absorber
43 cases
44 Upper lid member
45 Ink supply port
46 Seal Ring
47 Opening to the atmosphere
48 grooves
50 Cap member
55 Sealing member
A space

Claims (20)

At least a coloring material dissolved or dispersed in water, and water, and a wetting agent, Ri Do from an ink composition comprising a 2,4-diethyl-1,5-pentanediol, wherein the colorant is a pigment, An aqueous recording liquid, wherein the average particle diameter of the pigment is in the range of 10 nm to 200 nm .   2. The aqueous recording liquid according to claim 1, wherein the content of 2,4-diethyl-1,5-pentanediol is 0.1 to 5% by weight based on the total amount of the ink composition.   The aqueous recording liquid according to claim 1 or 2, wherein the content of the wetting agent is 5 to 50% by weight based on the total amount of the ink composition.   The aqueous recording according to any one of claims 1 to 3, wherein the ink composition further contains a surfactant in a range of 0.01 to 5% by weight based on the total amount of the ink composition. liquid. 5. The aqueous recording liquid according to claim 4, wherein the surfactant contains at least a polyoxyethylene alkyl ether acetate represented by the following general formula (1).
[Chemical 1]
R ₁ —O— (CH ₂ CH ₂ O) _m —CH ₂ COOM (1)
(In the formula, R ₁ is an alkyl group having 6 to 14 carbon atoms which may be branched, m is a natural number of 3 to 12, M represents an alkali metal ion, quaternary ammonium, quaternary phosphonium, or alkanolamine. .)   6. The aqueous recording liquid according to claim 1, wherein the wetting agent is a compound selected from at least one of diethylene glycol, triethylene glycol, or glycerin.   The ink composition further comprises at least one compound selected from 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. Item 7. The aqueous recording liquid according to any one of Items 1 to 6.   The aqueous recording liquid according to claim 1, further comprising 2-pyrrolidone in the ink composition. 9. An aqueous recording liquid obtained by adding, to an ink composition, a pigment dispersion in which a pigment is dispersed in water with a dispersant, and carboxyl groups are bonded to the dispersant. The aqueous recording liquid according to any one of the above . An aqueous recording liquid obtained by adding, to an ink composition, a pigment dispersion in which a pigment is dispersed in water with a dispersant, wherein the surface of the pigment is modified by bonding with a hydrophilic group. The aqueous recording liquid according to claim 1. The aqueous recording liquid according to claim 10, wherein the hydrophilic group is a carboxyl group. The aqueous recording liquid according to any one of claims 1 to 11, wherein the aqueous recording liquid is a recording method in which an aqueous recording liquid is ejected and ejected as droplets from an ejection port of a recording head to form an image on a recording medium. And a recording method. 13. The recording method according to claim 12, wherein in the recording method, thermal energy is applied to the aqueous recording liquid to eject and fly as droplets from the ejection port of the recording head to form an image on the recording medium. The recording method according to claim 12 or 13, wherein the recording medium contains pulp fibers as a main component, has a sizing degree of 10 s or more, and an air permeability of 5 to 50 s. A recording method for forming an image on a recording medium by ejecting and flying the aqueous recording liquid according to any one of claims 1 to 11 as a droplet from an ejection port of a recording head, wherein the ejection is performed per droplet. A recording method, wherein the quantity V (pl) satisfies the following formula (a):
[Expression 1]
2.5 × 10 ⁸ / R ^2.6 ≦ V ≦ 6.0 × 10 ⁸ / R ^2.6 (a)
(In the formula, R represents the maximum drop density when droplets are recorded on a recording medium having pulp fibers as a main component, a sizing degree of 10 s or more and an air permeability of 5 to 50 s, and the unit is dpi (dot per inch ) , and the unit of droplet discharge amount V is represented by picolitter (pl).) An image in which at least a part of a pixel region overlaps on a recording medium by ejecting and flying the aqueous recording liquid according to any one of claims 1 to 11 as a plurality of droplets from the same or separate ejection openings of a recording head. The recording method is characterized in that the discharge time difference between two droplets that overlap on the recording medium is 0.125 milliseconds or less. An ink cartridge comprising a recording liquid container that contains a recording liquid, wherein the recording liquid is the aqueous recording liquid according to any one of claims 1 to 11. An ink cartridge comprising a recording liquid storage part for storing a recording liquid and a recording head part for discharging recording liquid droplets, wherein the recording liquid is the aqueous recording liquid according to any one of claims 1 to 13. An ink cartridge characterized by that. 12. An ink jet recording apparatus comprising an ink cartridge having a recording liquid storage portion for storing a recording liquid and a recording head for discharging recording liquid droplets, wherein the recording liquid is any one of claims 1 to 11. An ink jet recording apparatus characterized by being an aqueous recording liquid. 12. An ink jet recording apparatus equipped with an ink cartridge including a recording liquid storage unit storing a recording liquid and a recording head for discharging recording liquid droplets, wherein the recording liquid is according to any one of claims 1 to 11. An ink jet recording apparatus which is an aqueous recording liquid.

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