JP2004182889A - Water-based recording liquid and recording method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based recording liquid having practically sufficient drying property usable in a high-speed inkjet printer without using a particular drying apparatus and free from the defects of the image such as strike-through and bleeding and provide a recording method to use the recording liquid. <P>SOLUTION: The water-based recording liquid at least contains water, a coloring agent soluble or dispersible in water, 2,4-diethyl-1,5-pentanediol, a ≤4C diol derivative and a water-soluble organic solvent as the ink composition. The recording method comprises the ejection of the water-based recording liquid through small nozzles in the form of flying droplets and the formation of an image on a recording medium. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００１３】
なお、一般式（１）で表される化合物はこれらに限定されるものではない。また、これらは、単独で用いても、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（一般式において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。
【００１４】
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浸透剤を添加してもよい。該浸透剤としては、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、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ブチルエーテル、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、テトラ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−ペンタンジオールである。
【００１５】
本発明における着色剤は、染料および／または顔料であることができる。着色剤として用いられる水溶性染料は、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、或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。これら着色剤は本発明の効果を妨げない範囲で添加される。
【００１６】
これら染料を具体的に挙げれば、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
直接性染料として
Ｃ．Ｉ．ダイレクト・イエロー １，１２，２４，２６，３３，４４，５０，８６，１２０，１３２，１４２，１４４，
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
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 ２，１２，１３，１４，１５，１８，２２，２３，２４，２７，２９，３５，３６，３８，３９，４６，４９，５１，５２，５４，５９，６８，６９，７０，７３，７８，８２，１０２，１０４，１０９，１１２Ｃ．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
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
等が使用できる。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、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。インク組成物中の着色剤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１〜１０重量％である。
【００１７】
本発明の着色剤としての顔料は、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。無機顔料としては、酸化チタンおよび酸化鉄、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、クロムイエローに加え、コンタクト法、ファーネス法、サーマル法等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、キレートアゾ顔料等を含む）、多環式顔料（例えば、フタロシアニン顔料、べリレン顔料、べリノン顔料、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、キノフラロン顔料等）、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等）、ニトロ顔料、ニトロソ顔料、アニリンブラック等を使用できる。これらの顔料のうち、水と親和性の良いものが好ましく用いられる。インク組成物中の着色剤としての顔料の添加量は、０．５〜２５重量％程度が好ましく、より好ましくは１〜１０重量％程度である。
本発明において好ましく用いられる顔料の具体例として、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、チャンネルブラツ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）等の有機顔料があげられる。さらに、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、４８：１、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。
【００１８】
その他、顔料（例えばカーボン）の表面を樹脂等で処理し、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ポキシル基等の官能基を付加し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。
【００１９】
本発明の好ましい態様によれば、水性記録液中の着色剤は平均粒径が１０ｎｍ〜２００ｎｍの範囲であることが好ましい。ここでいう平均粒径とは、体積累積パーセント５０％の値をさす。体積累積パーセント５０％の値を測定するには、例えば、インク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）といわれる方法を用いることができる。着色剤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しまう裏抜け（以下単に裏抜けと記す）を防止できる。顔料は、インクジェットで印字された際、記録媒体中でインク中の水や湿潤剤より記録媒体の中に入りにくく、乾燥性はやや遅くなるが裏抜けを防止することができる。着色剤の平均粒径が１０ｎｍ未満であると裏抜けを防止する効果が少なく、２００ｎｍ超ではインク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。
【００２０】
着色剤、とくに顔料は分散剤で水性媒体中に分散させて得られた顔料分散液として水性記録液に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液を使用することができる。分散剤として例えば以下のものが挙げられる。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、スチレンー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−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あげられる。これらの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、さらに好ましくは７，０００〜１５，０００である。
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宜添加されていればよい。分散剤としては、顔料に対して１：０．０６〜１：３（重量比）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。
【００２１】
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記録液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インクを得やすい。
顔料分散剤として使用する水溶性界面活性剤の具体例として、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。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。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。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。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宜添加されていればよい。
【００２２】
分散剤は、カルボキシル基が結合していることが好ましい。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ともに、印字後の記録媒体の耐水性がより向上する。更に、上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−ｎ−ブチル−２−エチル−１，３−プロパンジオールとを併用した場合においては、普通紙等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、且つ、裏抜けが少ないという効果が得られる。これは、カルボン酸の解離定数が他の酸系に比較して小さい為、顔料が記録媒体に付着した後、インクのｐＨ価の低下や、記録媒体表面近傍に存在するカルシウム等の多価金属イオンとの相互作用等により、分散剤自体の溶解度が低下し、分散剤自体や顔料が凝集する為と推定される。
【００２３】
また別の形態としては、着色剤（例えば顔料）が表面改質されカルボキシル基が直接顔料に結合され水中に分散されている形態も好ましい。これも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に、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ともに、印字後の記録媒体の耐水性がより向上する。またこの形態の記録液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のノズル付近の記録液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。
これらに用いられるブラックインク用の顔料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、耐光性、分散安定性に優れ、且つ安価である。
【００２４】
本発明の水性記録液には前記で説明した各成分の他に、従来知られている添加剤を加えることができる。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。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。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、スチレン系樹脂等があげられる。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ともに水に混合することによって得ることができる。
市販の樹脂エマルジョンとしては、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）等があげられる。本発明の水性記録液は、樹脂エマルジョンを、その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、着色成分の浸透を抑制し、さら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。
【００２５】
本発明の水性記録液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）および多糖類があげられ、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あげられる。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、セルロース等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。前記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ＨＯＣＨ_２（ＣＨＯＨ）ｎＣＨ_２ＯＨ（ここでｎは２〜５の整数を表す）で表される〕｝、酸化糖（例えば、アルドン酸、ウロン酸等）、アミノ酸、チオ酸誘導体等があげられる。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、ソルビット等があげられる。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。
【００２６】
その他、本発明の水性記録液は、アルギン酸ナトリウムを含有していてもよい。アルギン酸ナトリウムは、褐藻類にのみ含まれる物質で、主に細胞膜或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り、増粘作用、安定化作現、分散作用、ゲル化作用、フイルム形成作用等の効果がある。インクジェットインクに添加すると、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、異なる色間の惨み（カラーブリード）が改善できる。
【００２７】
また、防腐防黴剤として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、ぺンタクロロフェノールナトリウム等が使用できる。ｐＨ調整剤として、調合されるインクに悪影響をおよぼさずにｐＨを７以上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。また、キレート試薬として、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。防錆剤として、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、四硝酸ぺンタエリスリトール、ジシクロへキシルアンモニウムニトライト等がある。その他その目的に応じて水溶性紫外線吸収剤、水溶性赤外線吸収剤を添加することもできる。
【００２８】
本発明の水性記録液は、微細な吐出口より液滴として吐出、飛翔させ記録媒体にカラー画像を形成す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、水性ボールペン等の一般の筆記用具や記録計、ペンプロッター用の記録液として使用できることはいうまでもない。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。
インクジェット記録方法に使用する場合、記録液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、一般に記録液の粘度は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。
【００２９】
本発明の水性記録液に適合する記録媒体は、パルプ繊維を主成分としサイズ度１０ｓ以上、透気度５〜５０ｓであることが好ましい。ここでい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、透気度とは紙および板紙の透気度試験方法 ＪＩＳＰ８１１７−８０に従って行う。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超の場合は印字品質や乾燥性に問題はないが、必要以上に填量を添加しているため、コストが高くなってしまう。
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が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を主体としてもよい。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。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、スチレン一マレイン酸コポリマー、第４級アンモニウム塩、アルケニル無水コハク酸、石油樹脂系サイズ、エピクロルヒドリン、カチオン澱粉、アクリルアミド等がある。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。さらに紙力増強剤、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。
【００３０】
次に、本発明の水性記録液を記録液カートリッジ（インクカートリッジ）に収容し、このインクカートリッジをインクジェットプリンターに装着して、微細な吐出口より液滴として吐出、飛翔させ記録媒体に画像を形成する方法を添付図面を参照して説明するが、以下は構成例の一つに過ぎず、本発明になんら限定を加えるものではない。
図１は本発明の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（Ｂｋ）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。
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、即ち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。さらに、側板１とサブフレーム１２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。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。さらに、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、発泡部材或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。
【００３１】
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（水性記録液）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の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等のカートリッジ取扱い時、或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。また、大気開放口４７は、図２に示すように、酸素透過率が１００ｍｌ／ｍ^２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。このように大気開放口４７を酸素透過率が１００ｍｌ／ｍ^２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。
【００３２】
また、図４には、本発明の水性記録液を収容した記録液収容部と、記録液滴を吐出させるためのヘッド部を備えた記録カートリッジ（記録ユニット）の構成例を示す。以下に記録ユニットについて説明する。
記録ユニット３０は、シリアルタイプのものであり、ヘッド６と、このヘッド６に供給される水性記録液（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３４とで主要部が構成される。記録ユニット３０のヘッド６には、水性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記録ユニット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。本発明の記録液は、バブルやサーマル方式等の記録方法において、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及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。
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、ノズルを千鳥等任意の配列で、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、ここでいう記録装置とは、ＰＣやデジタルカメラ用の出力プリンタのみならず、ファックスやスキャナ、電話等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。
【００３３】
【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、実施例に記載の各成分の量（％）は重量基準である。
実施例１
下記処方のインク組成物を作成し、ｐＨが８〜９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のメンプレンフィルターで濃過を行いインク組成物を得た。
【００３４】
ダイレクトブルー １９９ ３．０重量％
グリセリン ７．０重量％
１，３−ブタンジオール ２８．０重量％
２，４−ジエチル−１，５−ペンタンジオール ４．０重量％
イオン交換水 残量
【００３５】
実施例２
下記処方のインク組成物を作成し、ｐＨが８〜９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０．２μｍのメンプレンフィルターで濃過を行いインク組成物を得た。
【００３６】
ダイレクトイエロー １３２ ２．５重量％
ジエチレングリコール １５．０重量％
１，３−ブタンジオール ２０．０重量％
２，４−ジエチル−１，５−ペンタンジオール ４．５重量％
イオン交換水 残量
【００３７】
実施例３
下記処方のインク組成物を作成し、ｐＨが８〜９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のメンプレンフィルターで濃過を行いインク組成物を得た。
【００３８】
アシッドレッド ２４９ ３．０重量％
グリセリン ７．０重量％
１，３−ブタンジオール ２８．０重量％
２，４−ジエチル−１，５−ペンタンジオール ２．５重量％
日光ケミカルズ（株）ＥＣＴＤ３ＮＥＸ ０．５重量％
（一般式（１）のＲ１：トリデシル基、ｍ：３、Ｍ：Ｎａ）
イオン交換水 残量
【００３９】
実施例４
下記組成物を用いる以外は実施例１と同様にして．ｐＨが８〜９になるように水酸化リチウム１０％水溶液にて調整してインク組成物とした。
【００４０】
ダイレクトブラック １６８ ５．０重量％
グリセリン ７．０重量％
１，３−ブタンジオール ２８．０重量％
２，４−ジエチル−１，５−ペンタンジオール ２．０重量％
２−エチル−１，３−ヘキサンジオール １５重量％
イオン交換水 残量
【００４１】
実施例５
下記処方のインク組成物を作成し、ｐＨが８〜９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のメンプレンフィルターで濃過を行いインク組成物を得た。
【００４２】
ダイレクトブラック １６８ ４．０重量％
グリセリン ７．０重量％
１，３−ブタンジオール ２８．０重量％
２，４−ジエチル−１，５−ペンタンジオール ４．０重量％
２−ピロリドン ２．０重量％
イオン交換水 残量
【００４３】
実施例６
下記処方で顔料分散液を調整した。下記処方の混合物をプレミックス後１リットルのベッセルに入れ、直径０．３ｍｍのジルコニアビーズを９００ｇ加え、カンペ製バッチ式卓上サンドミルで４８時間分散し、顔料分散液１を得た。平均粒径は１０２ｎｍであった（マイクロトラックＵＰＡ１５０を使用して測定）。
【００４４】
顔料分散液１
Ｃ．Ｉ．ピグメントブルー１５：３ １５．０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 ３．０重量％
イオン交換水 残量
【００４５】
インク組成物６
上記顔料分散液１を使用し、ｐＨが８〜９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のメンプレンフィルターで濃過を行いインク組成物を得た。
【００４６】
顔料分散液１ ２０．０重量％
グリセリン ７．０重量％
１，３−ブタンジオール ２８．０重量％
２，４−ジエチル−１，５−ペンタンジオール ２．０重量％
２，２，４−トリメチル−１，３−ペンタンジオール ２．０重量％
イオン交換水 残量
【００４７】
実施例７
下記処方で顔料分散液を調整した。下記処方の混合物をプレミックス後１リットルのベッセルに入れ、直径０．３ｍｍのジルコニアビーズを９００ｇ加え、カンペ製バッチ式卓上サンドミルで４８時間分散し、顔料分散液２を得た。平均粒径は１１４ｎｍであった（マイクロトラックＵＰＡ１５０を使用して測定）。
【００４８】
顔料分散液２
カーボンブラック １５．０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 ３．０重量％
イオン交換水 残量
【００４９】
インク組成物７
上記顔料分散液２を使用し、ｐＨが８〜９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のメンプレンフィルターで濃過を行いインク組成物を得た。
【００５０】
顔料分散液２ ３３．３３重量％
グリセリン ７．０重量％
１，３−ブタンジオール ２８．０重量％
日光ケミカルズ（株）ＥＣＴＤ６ＮＥＸ ０．５重量％
（一般式（１）のＲ１：トリデシル基、ｍ：６、Ｍ：Ｎａ）
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重量％
イオン交換水 残量
【００５１】
実施例８
下記組成物を用いる以外は実施例１と同様にして、ｐＨが８になるように水酸化リチウム１０ ％水溶液にて調整してインク組成物とした。
【００５２】
カルボン酸塩結合型カーボンブラック分散液 ３３．３３重量％
（キャボット社 ＣＡＢ−Ｏ−ＪＥＴ ３００）
グリセリン ７．０重量％
１，３−ブタンジオール ２８重量％
２，４−ジエチル−１，５−ペンタンジオール ４．０重量％
イオン交換水 残量
【００５３】
実施例９
下記組成物を用いる以外は実施例１と同様にして、ｐＨが８になるように水酸化リチウム１０ ％水溶液にて調整してインク組成物とした。
スルホン酸塩結合型カーボンブラック分散液 ２５重量％
（キャボット社 ＣＡＢ−Ｏ−ＪＥＴ ２００）
グリセリン ７．０重量％
１，３−ブタンジオール ２８重量％
２，４−ジエチル−１，５−ペンタンジオール ４．０重量％
イオン交換水 残量
【００５４】
比較例１
下記組成物を用いる以外は実施例１と同様にして、ｐＨが８〜９になるように水酸化リチウム １０％水溶液にて調整してインク組成物とした。
【００５５】
ダイレクトブラック １６８ ４．０重量％
グリセリン ７．０重量％
トリエチレングリコール ２８．０重量％
イオン交換水 残量
【００５６】
比較例２
下記組成物を用いる以外は実施例１と同様にして、ｐＨが８〜９になるように水酸化ナトリウム１０％水溶液にて調整してインク組成物とした。
【００５７】
ダイレクトブラック １６８ ４．０重量％
グリセリン ７．０重量％
ジエチレングリコール ２８．０重量％
２−メチル−２−プロピル−１，３−プロパンジオール ２．０重量％
イオン交換水 残量
【００５８】
比較例３
下記組成物を用いる以外は実施例１と同様にして、ｐＨが８〜９になるように水酸化ナトリウム１０％水溶液にて調整してインク組成物とした。
【００５９】
ダイレクトブラック １６８ ４．０重量％
グリセリン ７．０重量％
ジエチレングリコール ２８．０重量％
２−メチル−２−プロピル−１，３−プロパンジオール ４．０重量％
イオン交換水 残量
【００６０】
比較例４
下記組成物を用いる以外は実施例１と同様にして、ｐＨが８〜９になるように水酸化リチウム１０％水溶液にて調整してインク組成物とした。
【００６１】
実施例７の顔料分散液２ ３３．３３重量％
グリセリン ７．０重量％
トリエチレングリコール ２３．０重量％
トリエチレングリコールモノブチルエーテル ４．０重量％
イオン交換水 残量
【００６２】
次に、上記実施例および比較例について下記の試験を行った。その結果を表１に記す。
（１）インクの表面張力
ＫＲＵＳＳ製自動表面張力計Ｋ１０ＳＴを使用して２５℃におけるインクの表面張力を測定した（単位はｍＮ／ｍ ）。
（２）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）を用いピエゾ方式のインクジェットプリンター（（株）リコー製ＩＰＳＩＯ ＪＥＴ ３００ ）で印字を行い、乾燥後、２色重ね部境界の惨み、画像惨み、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。
（３）画像の乾燥性
記録媒体にべタ画像印字後の画像に０．１ｋ ｇ／ｃｍ^２の圧力で濃紙を押しつけインクが源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〇と判定した。
（４）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となる様にべタ画像を形成した。この画像を裏面から目視観察し、べタ画像と白地部分の境界が明らで両面印字に使用する場合支障がある場合は×、べ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べルの場合は○、べ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。
（５）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、マーキングぺンで擦過し、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。
（６）画像の埋まり
乾燥後、べタ画像を目視で観察し、インクで均一に記録媒体が着色している場合は〇、地肌が見えるような不均一な着色の場合は×とした。
（７）保存性
インクをインクジェットプリンタ一にセットしたまま、６０℃、７日間放置し、その後インクジェットプリンターのクリーニング操作で復帰可能ならば〇、不可能ならば×とした。
【００６３】
【表１】

【００６４】
上記表の結果に示されるように本発明の水性記録液は、表面張力が低下し、インクと紙表面との濡れ性が向上し、紙への浸透速度が高まるだけではなく、従来知られるような界面活性剤を中心として浸透性を高めた場合にくらべ、画像劣化がきわめて少ない。また着色剤の種類の如何に関わらず浸透速度もほぼ同等である。
【００６５】
【発明の効果】
本発明によれば、高速印字が可能なインクジェットプリンターにおいて特別な乾燥装置を使用しなくても実用上十分な乾燥性を有し、画像の裏抜けあるいは滲み等の画像劣化のない水性記録液およびこれを用いた記録方法が提供される。本発明の水性記録液は、ピエゾ方式、サーマル方式等のオンディマンド法や荷電制御方式等の連続噴射法等のインクジェット記録用に適し、特に所謂普通紙に対するカラーインクとして優れた特性を示すものであり、水性筆記用具、記録計、ペンプロッター用水性インクとしても用いられ得る。
【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構成例を示す概略正面図である。
【図２】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】インクカートリッジの正断面図である。
【図４】本発明の水性記録液を収容した記録液収容部と、記録液滴を吐出させるためのヘッド部を備えた記録カートリッジの構成例を説明するための図である。
【符号の説明】
１，２ 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
７ インクカートリッジ
１５ 搬送ローラ
１６ 用紙
２１ 信頼性維持回復機構
２２ キャップ手段
２３ ホルダ
２４ リンク部材
２８ ワイパブレード
２９ ブレードアーム
３０ 記録ユニット
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
５５ フィルム状シール部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an aqueous recording liquid and a recording method using the same, and in particular, has a practically sufficient drying property without using a special drying device in an inkjet printer capable of high-speed printing, The present invention relates to an aqueous recording liquid free from image deterioration such as strike-through or bleeding of an image, and a recording method using the same. The aqueous recording liquid of the present invention is suitable for ink jet recording such as a piezo method, an on-demand method such as a thermal method, and a continuous ejection method such as a charge control method, and particularly exhibits excellent characteristics as a color ink for so-called plain paper. , Water-based writing utensils, recorders, and water-based inks for pen plotters.
[0002]
[Prior art]
2. Description of the Related Art In recent years, ink jet recording systems have rapidly become widespread in recent years because of their advantages such as small size, low cost, low running cost and low noise. Inkjet printers capable of printing on various non-coated plain papers such as electrophotographic transfer paper, printing paper, typewriter paper, wire dot printer paper, word processor paper, letter paper, and report paper have also been put on the market. In these ink jet printers, various proposals have been made to improve the ink absorbency so that higher quality images can be obtained.
However, it is difficult to satisfy all of the color reproducibility of an image, water fastness, light fastness, image drying, image misery, and ejection reliability. In particular, in the case of a color printer, even if there is no image quality deterioration in the yellow, magenta, and cyan single-color printing portions, the image quality is likely to deteriorate in the two-color overlapping portion of red, green, and blue. In particular, when drying is performed without using a fixing device, in order to solve this problem, Japanese Patent Application Laid-Open No. 55-29546 discloses a method of improving the drying property by increasing the permeability of ink. However, since the amount of the surfactant used is large, it is extremely disastrous depending on the type of paper.
Patent Document 2 (Japanese Patent Publication No. 60-23793) discloses a technique in which a dialkyl sulfosuccinic acid is used as a surfactant to improve drying properties and prevent image deterioration. There is a problem that the pixel diameter is remarkably different, the image density is remarkably reduced, and the activator is decomposed on the alkali side, and the activation effect is lost during storage.
Patent Document 3 (Japanese Patent Publication No. 58-6752) discloses a quick-drying ink using a surfactant that is an ethylene oxide adduct having an acetylene bond. According to this technology, it is said that the penetrability is improved and the misery is reduced. However, depending on the type of the colorant, for example, an ink using a direct dye such as Direct Black 168 has a hydrophobic interaction with the colorant. Therefore, there is a problem that the drying speed is not improved, or the ink using a pigment such as carbon black is apt to agglomerate, and it is easy to cause clogging of nozzles and bending of the ink jetting direction.
Also, in order to improve the drying speed, Patent Document 4 (Japanese Patent Application Laid-Open No. 8-113439) proposes an ink containing a dye and a water-soluble glycol ether, and Patent Document 5 (Japanese Patent Application Laid-Open No. 10-95941). In Japanese Patent Application Laid-Open Publication No. HEI 9-207, an ink composition comprising a pigment, a glycol ether such as diethylene glycol mono-n-butyl ether, and water is 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.
Patent Document 6 (Japanese Patent Application Laid-Open No. 56-57862) discloses an ink to which a strongly basic substance is added. However, although it is effective for rosin-sized acidic paper, alkyl ketene dimer and alkenyl are effective. It has no effect on paper using sulfosuccinic acid as a sizing agent. In addition, even with acidic paper, there is no effect in the two-color overlapping portion.
Patent Document 7 (JP-A-1-203483) discloses a recording liquid characterized by containing a polyhydric alcohol derivative and pectin, which is prepared by adding pectin as a thickener. However, although pectin is prevented, there is a problem that pectin lacks ejection stability after printing is stopped because it is nonionic having a hydroxyl group as a hydrophilic group.
Patent Document 8 (Japanese Patent Application Laid-Open No. 2-36276) discloses 2-propanol as a component for improving frequency response and fixability, but has problems in safety such as toxicity and flammability. .
Further, since there is a problem that the foaming property of the ink is increased when the above-described surfactant is used for the purpose of increasing the permeability, as a method of increasing the permeability with a material other than the surfactant, Patent Document 9 (JP-A-62-169875) discloses a C4-C6 diol derivative, and Patent Document 10 (JP-A-3-2286) discloses 2-methylpentane-2,4-diol. (JP-A-6-508392) discloses a diol derivative having a solubility in water at 25 ° C. of 4.5% by weight and 6 to 8 carbon atoms in Patent Document 12 (JP-A-9-268266). Discloses an ink using a 3,3-propanediol derivative or the like. However, since these diol derivatives have high solubility in water, the surface tension of the ink, which is one measure of the permeability, cannot be reduced, and the permeability for improving the drying property of the ink can be secured. Not done.
The aqueous ink composition using a diol derivative is also disclosed in Patent Documents 13 to 16 below.
[0003]
[Patent Document 1]
JP-A-55-29546
[Patent Document 2]
Japanese Patent Publication No. 60-23793
[Patent Document 3]
JP-B-58-6752
[Patent Document 4]
JP-A-8-113439
[Patent Document 5]
JP-A-10-95941
[Patent Document 6]
JP-A-56-57862
[Patent Document 7]
JP-A-1-203483
[Patent Document 8]
JP-A-2-36276
[Patent Document 9]
JP-A-62-169875
[Patent Document 10]
JP-A-3-2286
[Patent Document 11]
Japanese Patent Publication No. 6-508392
[Patent Document 12]
JP-A-9-268266
[Patent Document 13]
JP-A-6-157959
[Patent Document 14]
JP 2001-172534 A
[Patent Document 15]
JP 2001-254036 A
[Patent Document 16]
JP 2001-254037 A
[0004]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an ink jet printer capable of high-speed printing, which has practically sufficient drying properties without using a special drying device, and which does not cause image deterioration such as image strikethrough or bleeding. And a recording method using the same.
[0005]
[Means for Solving the Problems]
The present inventor studied various diol derivatives as a material for enhancing the permeability to paper in order to improve the drying property of the aqueous recording liquid, and found that 2,4-diethyl-1,5-pentanediol was used as the recording liquid. By adding a small amount, the surface tension becomes 35 mJ / m ² Not only is it possible to improve the wettability between the recording liquid and the paper surface and increase the permeation rate to the paper, but also to increase the permeation mainly with a surfactant as conventionally known. As compared with the case, it was found that the image deterioration was extremely small, and the present invention was able to be achieved.
[0006]
The invention of claim 1 provides at least water, a colorant soluble or dispersible in water, 2,4-diethyl-1,5-pentanediol, a diol derivative having 4 or less carbon atoms, and a water-soluble organic solvent. As an ink composition.
The invention according to claim 2 is characterized in that 2,4-diethyl-1,5-pentanediol is contained in a proportion of 0.1 to 5% by weight based on the total weight of the ink composition. 2. The aqueous recording liquid according to item 1.
The invention according to claim 3 is the aqueous recording liquid according to claim 1 or 2, wherein the surfactant is contained in a ratio of 0.01 to 5% by weight based on the total weight of the ink composition. is there.
The invention according to claim 4 is the aqueous recording liquid according to claim 3, wherein a polyoxyethylene alkyl ether acetate represented by the following general formula (1) is used as the surfactant.
R1-O- (CH ₂ CH ₂ O) m-CH ₂ COOM ... (1)
(Wherein, R1 represents an alkyl group having 6 to 14 carbon atoms which may be branched, m represents a natural number of 3 to 12, and M represents an alkali metal ion, quaternary ammonium, quaternary phosphonium, or alkanolamine)
According to a fifth aspect of the present invention, the aqueous recording liquid further comprises at least one selected from the group consisting of 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. The aqueous recording liquid according to any one of claims 1 to 4, wherein the aqueous recording liquid is contained.
The invention according to claim 6 is the aqueous recording liquid according to any one of claims 1 to 5, wherein the aqueous recording liquid further contains 2-pyrrolidone.
The invention according to claim 7 is the aqueous recording liquid according to any one of claims 1 to 6, wherein the colorant is a pigment having an average particle size of 50 nm to 200 nm.
The invention according to claim 8 is characterized in that the colorant is a pigment dispersed in water by a dispersant to which a carboxyl group is bonded, and the aqueous solution according to any one of claims 1 to 7, wherein It is a recording liquid.
The invention according to claim 9 is characterized in that the colorant is a pigment which is modified by binding a carboxyl group to its surface and can be dispersed in water. Aqueous recording liquid.
The invention according to claim 10 is characterized in that the colorant is a pigment that is modified by bonding a sulfonic acid group to its surface and can be dispersed in water. It is an aqueous recording liquid of the description.
An eleventh aspect of the present invention is characterized in that the aqueous recording liquid according to any one of the first to tenth aspects is ejected as a droplet from a fine ejection port to fly, thereby forming an image on a recording medium. It is a recording method.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail.
As described above, the aqueous recording liquid of the present invention contains 2,4-diethyl-1,5-pentanediol as an essential component in the ink composition. Although 2,4-diethyl-1,5-pentanediol has a solubility in water of 2% by weight or less, the combined use of a diol derivative having a carbon number of 4 or less described below results in 5% by weight of the recording liquid. Can be dissolved up to Conversely, because of its low solubility in water, even a small amount of addition can lower the surface tension.
The 2,4-diethyl-1,5-pentanediol is preferably contained in a ratio of 0.1 to 5% by weight, and more preferably 0.5 to 4.0% by weight, based on the total weight of the ink composition. preferable. If it is less than 0.1% by weight, the effect of enhancing permeability is small, and if it is more than 5% by weight, it does not dissolve stably in the composition, and there is a problem in storage stability of the composition and jetting stability by inkjet. .
In addition, in a recording method such as a so-called bubble or thermal method in which recording is performed by applying thermal energy to the ink and discharging the ink from the fine holes to fill the liquid, a method of adding 2-propanol to obtain discharge stability is known. However, in the present invention, the use of 2,4-diethyl-1,5-pentanediol instead improves the wettability to a thermal element, and enables a small amount of addition. Discharge stability and frequency stability are obtained, and safety issues associated with the use of 2-propanol are also ameliorated.
[0008]
The aqueous recording liquid of the present invention contains a diol derivative having 4 or less carbon atoms as an essential component.
Specific examples of the diol derivative having 4 or less carbon atoms include ethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. , 3-butanediol is preferred.
A diol derivative having 4 or less carbon atoms can enhance the dissolution stability of 2,4-diethyl-1,5-pentanediol and can also prevent clogging due to drying of the aqueous recording liquid. Therefore, the aqueous recording liquid of the present invention hardly causes clogging and can perform normal printing even when moisture in the recording liquid evaporates at the discharge port of the inkjet head, for example. It has also been found that even if clogging occurs, normal printing can be restored by a simple cleaning operation. The diol derivative having 4 or less carbon atoms is preferably added at a ratio of 5 to 50% by weight, preferably 10 to 40% by weight based on the total weight of the ink composition. When the amount is less than 5% by weight, the storage stability of the aqueous recording liquid and the jetting stability by the ink jet are inferior.
[0009]
The aqueous recording liquid of the present invention uses water as a liquid medium. However, in order to make the recording liquid have desired physical properties, to further prevent clogging due to drying, and to further improve the stability of the recording liquid. The following water-soluble organic solvents can be used in combination as a wetting agent for the purpose of, for example, making the composition wet. Examples of such a water-soluble organic solvent include diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerin, and 1,2,6-hexane. Polyhydric alcohols such as triol, 1,2,4-butanetriol, 1,2,3-butanetriol, pentantriol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether; Polyhydric alcohol alkyl ethers such as diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; ethylene glycol Polyhydric alcohol aryl ethers such as monophenyl ether and ethylene glycol monobenzyl ether; 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε Nitrogen-containing heterocyclic compounds such as caprolactam and γ-butyrolactone; amides such as formamide, N-methylformamide, N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine and the like. Amines; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol; propylene carbonate, ethylene carbonate and the like. These water-soluble organic solvents are used alone or as a mixture of two or more.
Above all, when diethylene glycol, triethylene glycol and / or glycerin are added, more excellent effects are obtained in preventing clogging due to drying of the aqueous recording liquid, that is, in preventing jetting characteristics failure due to water evaporation, and improving dissolution stability of the aqueous recording liquid. Is obtained.
The water-soluble organic solvent is preferably added in a range of 5 to 50% by weight based on the total weight of the ink composition.
[0010]
The present inventor has also found that the addition of 2-pyrrolidone provides an excellent effect of improving image density and preventing strike-through without impairing the permeability of the ink into paper. This is because the inclusion of 2-pyrrolidone makes it easier for the ink to wet and spread on the paper surface and relatively suppresses penetration into the thickness direction of the paper, so that the colorant is easily retained near the paper surface. It is speculated that there is. The amount of 2-pyrrolidone added is preferably 0.1% by weight to 10% by weight, and more preferably 0.5% by weight to 5% by weight, based on the total weight of the ink composition.
[0011]
Further, the aqueous recording liquid of the present invention preferably further contains a surfactant. As a result, a synergistic effect with the essential components of the recording liquid of the present invention is exhibited, the wettability between the ink and the paper surface is further improved, the permeation speed to the paper is increased, and the problem with the conventional permeation type ink is solved. The image density can be prevented from being reduced and strike-through can be prevented. In addition, there is an advantage that the solvent smell is smaller than that of a conventional ink in which a large amount of ethers of a polyhydric alcohol is added to increase the permeability.
The addition amount of the surfactant in the ink composition is 0.01% by weight to 5.0% by weight, and preferably 0.1% by weight to 3.0% by weight. If the content is less than 0.01% by weight, the effect of the addition is not obtained. If the content is more than 5.0% by weight, the permeability to the recording medium becomes unnecessarily high, and there is a problem that the image density is reduced and strikethrough occurs.
Examples of the surfactant used in the present invention include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether acetate, sodium laurate, and ammonium salts of polyoxyethylene alkyl ether sulfate. Cationic surfactants such as quaternary ammonium salts, amphoteric surfactants such as imidazoline derivatives, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl Amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, acetylene alcohol with ethylene oxide Nonionic surfactants such things like. In particular, a surfactant of an anionic surfactant is preferable, and among them, a polyoxyethylene alkyl ether acetate represented by the following general formula (1) is preferable. When this is used, the filling of the image is improved, and an excellent effect in increasing the image density can be obtained.
R1-O- (CH ₂ CH ₂ O) m-CH ₂ COOM ... (1)
(Wherein, R1 represents an alkyl group having 6 to 14 carbon atoms which may be branched, m represents a natural number of 3 to 12, and M represents an alkali metal ion, quaternary ammonium, quaternary phosphonium, or alkanolamine. )
Specific examples of the compound represented by the general formula (1) are shown below in free acid form.
[0012]
Embedded image

[0013]
The compound represented by the general formula (1) is not limited to these. These may be used alone or as a mixture of two or more. Commercially available surfactants containing this compound as a main component include ECTD3NEX (R1: tridecyl group, m: 3, M: Na in the general formula) and ECT3 (R1: Surfactants such as tridecyl group, m: 3, M: H) and ECTD6NEX (R1: tridecyl group, m: 6, M: Na) can also be used.
[0014]
In addition to 2,4-diethyl-1,5-pentanediol, a penetrant may be added for the purpose of adjusting the surface tension and the like. Examples of the penetrant include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol butyl ether and ethylene glycol monophenyl ether. Alkyl and aryl ethers of polyhydric alcohols such as allyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether, and fluorine-based surfactants And lower alcohols such as ethanol, 2-propanol and the like. 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol.
[0015]
The colorant in the present invention can be a dye and / or a pigment. As the water-soluble dye used as the coloring agent, dyes classified into acid dyes, direct dyes, basic dyes, reactive dyes and food dyes in a color index are used. These dyes may be used by mixing a plurality of types, or may be used by mixing with other dyes such as pigments as necessary. These colorants are added in a range that does not hinder the effects of the present invention.
[0016]
Specific examples of these dyes include acid dyes and food dyes.
C. I. Acid Yellow 17,23,42,44,79,142
C. 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. Acid Blue 9,29,45,92,249
C. I. Acid Black 1,2,7,24,26,94
C. I. Food Yellow 2,3,4
C. I. Food Red 7,9,14
C. I. Food black 1,2
As direct dye
C. I. Direct Yellow 1,12,24,26,33,44,50,86,120,132,142,144,
C. I. Direct Red 1,4,9,13,17,20,28,31,39,80,81,83,89,225,227
C. I. Direct orange 26,29,62,102
C. I. Direct Blue 1,2,6,15,22,25,71,76,79,86,87,90,98,163,165,199,202
C. I. Direct Black 19,22,32,38,51,56,71,74,75,77,154,168,171
As a basic dye
C. 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. 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, 112C. 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
C. I. Basic Black 2,8
As a reactive dye
C. I. Reactive Black 3,4,7,11,12,17
C. I. Reactive Yellow 1,5,11,13,14,20,21,22,25,40,47,51,55,65,67
C. I. Reactive Red 1,14,17,25,26,32,37,44,46,55,60,66,74,79,96,97
C. I. Reactive Blue 1,2,7,14,15,23,32,35,38,41,63,80,95
Etc. can be used. As the dye, acid dyes and direct dyes can be particularly preferably used, and the effects of improving the dissolution stability of the aqueous recording liquid and excellent color tone, water resistance and light resistance can be obtained. The amount of the dye as a colorant in the ink composition is preferably 0.5 to 25% by weight, and more preferably 1 to 10% by weight.
[0017]
As the pigment as the coloring agent of the present invention, an inorganic pigment or an organic pigment can be used without any particular limitation. Inorganic pigments include titanium oxide and iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon produced by a known method such as a contact method, a furnace method, and a thermal method. Black can be used. Examples of the organic pigment include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelated azo pigments, etc.), and polycyclic pigments (for example, phthalocyanine pigments, berylene pigments, velinone pigments, anthraquinone pigments, quinacridone pigments) , Dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinoflurone pigments, etc., dye chelates (eg, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used. . Among these pigments, those having good affinity for water are preferably used. The amount of the pigment added as a coloring agent in the ink composition is preferably about 0.5 to 25% by weight, and more preferably about 1 to 10% by weight.
Specific examples of the pigment preferably used in the present invention include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, or copper, iron (C.I. Pigment Black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1). Further, for color, 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, C.I. 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: 1, 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, C.I. I. Pigment Violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36 and the like.
[0018]
In addition, a pigment (for example, carbon) is treated with a resin or the like to treat the surface of the pigment with a resin or the like, and can be dispersed in water. Processed pigments and the like can be used. Alternatively, the pigment may be included in microcapsules so that the pigment can be dispersed in water.
[0019]
According to a preferred embodiment of the present invention, the colorant in the aqueous recording liquid preferably has an average particle size in a range of 10 nm to 200 nm. Here, the average particle size means a value of 50% by volume cumulative percentage. In order to measure the value of the volume cumulative percentage of 50%, for example, a laser beam is radiated to particles undergoing Brownian motion in the ink, and the frequency (light frequency) of light returning from the particles (backscattered light) is measured. ), A method called a dynamic light scattering method (Doppler scattered light analysis) for obtaining the particle diameter from the change amount can be used. When the coloring agent is a pigment, water resistance and light resistance are improved, and further, strike-through (hereinafter, simply referred to as strike-through) in which the ink escapes from the layer of the recording medium and exudes to the back surface can be prevented. The pigment is less likely to enter the recording medium than the water and the wetting agent in the ink in the recording medium when printed by inkjet, and the drying property is slightly slower, but strike-through can be prevented. If the average particle size of the colorant is less than 10 nm, the effect of preventing strike-through is small, and if it exceeds 200 nm, the dispersion stability of the ink is poor, and the particle size becomes large due to aggregation or the like during storage, resulting in poor ejection stability.
[0020]
The colorant, particularly the pigment, is preferably added to the aqueous recording liquid as a pigment dispersion obtained by dispersing the colorant, particularly a pigment, in an aqueous medium. As a preferred dispersant, a known dispersion used for preparing a conventionally known pigment dispersion can be used. Examples of the dispersant include the following. Polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-alkyl acrylate copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer Polymer, styrene-acrylic acid-alkyl acrylate copolymer, styrene-methacrylic acid-alkyl acrylate copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-maleic acid copolymer, Vinyl naphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic And acid copolymers. These copolymers preferably have a weight average molecular weight of 3,000 to 50,000, more preferably 5,000 to 30,000, and still more preferably 7,000 to 15,000.
The addition amount of the dispersant may be appropriately added as long as the pigment is stably dispersed and other effects of the present invention are not lost. The dispersant is preferably in the range of 1: 0.06 to 1: 3 (weight ratio) with respect to the pigment, and more preferably in the range of 1: 0.125 to 1: 3.
[0021]
In addition, a water-soluble surfactant can be used as a pigment dispersant. In this case, the increase in the viscosity of the recording liquid with respect to the amount used is smaller than when the polymer dispersant is used, and it is easy to obtain a pigment ink having good ejection characteristics when used in an inkjet recording method.
Specific examples of the water-soluble surfactant used as the pigment dispersant include, for example, an alkyl surfactant such as alkyl allyl or alkyl naphthalene sulfonate, alkyl phosphate, alkyl sulfate, alkyl sulfonate, and alkyl ether sulfate. , Alkyl sulfosuccinate, alkyl ester sulfate, alkyl benzene sulfonate, alkyl diphenyl ether disulfonate, alkyl aryl ether phosphate, alkyl aryl ether sulfate, alkyl aryl ether ester sulfate, olefin sulfonate, alkane olefin sulfone Acid salt, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl ether sulfate, ether carboxylate, sulfosuccinate, α-sulfofatty acid ester Fatty acid salts, condensates of higher fatty acid and an amino acid, a naphthenic acid salt or the like. Examples of the cationic surfactant include an alkylamine salt, a dialkylamine salt, an aliphatic amine salt, a benzalkonium salt, a quaternary ammonium salt, an alkylpyridinium salt, an imidazolinium salt, a sulfonium salt, and a phosphonium salt. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene glycol ester, polyoxyethylene fatty acid amide, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxy. Propylene glycol, glycerin ester, sorbitan ester, sucrose ester, polyoxyethylene ether of glycerin ester, polyoxyethylene ether of sorbitan ester, polyoxyethylene ether of sorbitol ester, fatty acid alkanolamide, amine oxide, polyoxyethylene alkylamine, Glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fat Esters, polyoxyethylene sorbitol fatty acid esters, alkyl (poly) Gurikokishido like. Examples of the amphoteric surfactant include imidazoline derivatives such as imidazolinium betaine, dimethyl alkyl lauryl betaine, alkyl glycine, and alkyl di (aminoethyl) glycine. The amount of the surfactant as a dispersant may be appropriately added as long as the pigment is stably dispersed and other effects of the present invention are not lost.
[0022]
The dispersant preferably has a carboxyl group bonded thereto. When a carboxyl group is bonded to the dispersant, not only the dispersion stability is improved, but also high-quality printing quality is obtained, and the water resistance of the recording medium after printing is further improved. Further, an effect of preventing the strike-through is obtained. In particular, when a pigment dispersed with a dispersant having a carboxyl group bonded thereto and 2-n-butyl-2-ethyl-1,3-propanediol are used in combination, a relatively large size such as plain paper is used. Even when printing is performed on a high recording medium, a sufficient drying speed can be obtained, and the effect of reducing strike-through can be obtained. This is because the dissociation constant of the carboxylic acid is smaller than that of other acid systems, so that after the pigment adheres to the recording medium, the pH value of the ink decreases, or the polyvalent metal such as calcium existing 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.
[0023]
As another form, a form in which a colorant (for example, a pigment) is surface-modified and a carboxyl group is directly bonded to the pigment and dispersed in water is also preferable. Again, because the pigment is surface-modified and the carboxyl groups are bonded, not only the dispersion stability is improved, but also high-quality printing quality is obtained, and the water resistance of the recording medium after printing is further improved. . In addition, since the recording liquid in this mode has excellent redispersibility after drying, printing is paused for a long time, and even if the water of the recording liquid near the nozzles of the inkjet head evaporates, clogging does not occur and simple cleaning operation is easy. And good printing can be performed.
The pigment for the black ink used in these is preferably carbon black. As a black ink, carbon black is excellent in color tone, excellent in water resistance, light resistance, dispersion stability, and inexpensive.
[0024]
Conventionally known additives can be added to the aqueous recording liquid of the present invention in addition to the components described above. For example, a resin emulsion may be added to the aqueous recording liquid of the present invention. 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. Examples of the resin component of the dispersed phase include an acrylic resin, a vinyl acetate resin, a styrene-butadiene resin, a vinyl chloride resin, an acryl-styrene resin, a butadiene resin, and a styrene resin. 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.
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 and Chemicals, Inc.), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink and Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion, Seiden Chemical Co., Ltd.) Manufactured by the company). 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 1 to 25% by weight. The resin emulsion has a property of thickening and aggregating, has an effect of suppressing penetration of a coloring component, and further promoting fixation to a recording medium. Further, depending on the type of the resin emulsion, a film is formed on the recording medium, which has the effect of improving the abrasion resistance of the printed matter.
[0025]
The aqueous recording liquid of the present invention may contain sugar. Examples of saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, Lactose, sucrose, trehalose, maltotriose and the like. Here, the polysaccharide means a saccharide in a broad sense, and is used to include substances widely existing in nature such as α-cyclodextrin and cellulose. Examples of the saccharide derivatives include reducing sugars of the saccharides described above, for example, sugar alcohols [formula HOCH ₂ (CHOH) nCH ₂ OH (where n represents an integer of 2 to 5)}, oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, and thioic acid derivatives. Particularly, sugar alcohols are preferred, and specific examples include maltitol, sorbitol and the like. The content of these saccharides is appropriately in the range of 0.1 to 40% by weight, preferably 0.5 to 30% by weight of the ink composition.
[0026]
In addition, the aqueous recording liquid of the present invention may contain sodium alginate. Sodium alginate is a substance contained only in brown algae and is a hydrophilic polyelectrolyte that mainly exists as a cell membrane or intercellular substance, and has a thickening action, stabilizing action, dispersing action, gelling action, and film forming action. And so on. When added to an inkjet ink, the misery between different colors (color bleed) can be improved by a change in viscosity due to pH, precipitation by salts, and gelation with polyvalent cations.
[0027]
Further, as a preservative and fungicide, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used. As the pH adjuster, any substance can be used as long as it can adjust the pH to 7 or more without adversely affecting the prepared ink. 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 include hydroxides, carbonates of alkali metals such as lithium carbonate, sodium carbonate, and potassium carbonate. Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uramildiacetate. Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and the like. In addition, a water-soluble ultraviolet absorber and a water-soluble infrared absorber can be added according to the purpose.
[0028]
The aqueous recording liquid of the present invention is particularly suitably used for an ink jet recording method of forming a color image on a recording medium by discharging and flying as droplets from a fine discharge port. Needless to say, it can be used as a recording liquid for writing instruments, recorders and pen plotters. Further, the aqueous recording liquid of the present invention is not limited to the use described above.
When used in an inkjet recording method, it is necessary to adjust the viscosity of the recording liquid to a desired value. Although it depends on the ejection force of the head, it is generally preferable that the viscosity of the recording liquid is 10 mPa · s or less. If the pressure is higher than 10 mPa · s, sufficient discharge cannot be performed by the ink jet, and the problem of image failure often occurs.
[0029]
The recording medium compatible with the aqueous recording liquid of the present invention preferably contains pulp fibers as a main component and has a size of 10 s or more and an air permeability of 5 to 50 s. Here, the sizing degree is measured in accordance with JIS P8122-76, a test method for stiffness of paper, and the air permeability is measured in accordance with JISP8117-80, a test method for air permeability of paper and paperboard. If the size is smaller than 10 s, the recording liquid penetrates to the back surface and strikethrough occurs. If the air permeability is smaller than 5 s, the recording liquid also penetrates to the back surface and strikethrough occurs. Although there is no problem with the printing quality and drying property, the cost is increased because the filler is added more than necessary.
As the material of the pulp fiber used in the present invention, any material that does not affect the ink jet process can be used irrespective of the type of pulp and the treatment method. Further, non-wood pulp (kenaf, flax, bamboo, seaweed, etc.) or waste paper pulp may be used or may be mainly used. Preferably, it is a chemical pulp represented by LBKP or NBKP. Papermaking of these pulp is carried out by a conventional method using a known sizing agent, filler and other papermaking auxiliaries as required, like ordinary plain paper. Examples of the sizing agent include rosin size, AKD, sodium chloride, potassium chloride, styrene-maleic acid copolymer, quaternary ammonium salt, alkenyl succinic anhydride, petroleum resin size, epichlorohydrin, 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 retention enhancer, a fixing agent, a dye, and other papermaking aids are added.
[0030]
Next, the aqueous recording liquid of the present invention is accommodated in a recording liquid cartridge (ink cartridge), and this ink cartridge is mounted on an ink jet printer, and discharged as fine droplets from fine discharge ports to form an image on a recording medium. The method will be described with reference to the accompanying drawings, but the following is only one of configuration examples and does not limit the present invention in any way.
FIG. 1 is a schematic front view of a mechanism section of a serial type ink jet recording apparatus equipped with an ink cartridge provided with a recording liquid storage section storing a recording liquid of the present invention.
The mechanism of the ink jet recording apparatus is configured such that a main support guide rod 3 and a sub support guide rod 4 are horizontally laid between side plates 1 and 2 on both sides in a substantially horizontal positional relationship. The carriage unit 5 is slidably supported in the main scanning direction by the rod 4. The carriage unit 5 has four heads 6 that respectively eject yellow (Y) ink, magenta (M) ink, cyan (C) ink, and black (Bk) ink, and has ejection surfaces (nozzle surfaces) 6a. Four ink cartridges 7y, 7m, 7c, and 7k, each of which is an ink supply unit for supplying ink to each of the four heads 6, are mounted on the head 6 of the carriage unit 5 downward. Is replaceably mounted.
The carriage unit 5 is connected to a timing belt 11 stretched between a driving pulley (driving timing pulley) 9 rotated by the main scanning motor 8 and a driven pulley (idler pulley) 10 so that the main scanning motor 8 is driven. By controlling the drive, the carriage 5, that is, the four heads 6, is 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 transport roller 15 for feeding the paper 16 in a sub-scanning direction orthogonal to the main scanning direction is provided between the sub-frames 13 and 14. It is held rotatably. A sub-scanning motor 17 is provided on the side of the sub-frame 14, and a gear 18 fixed to a rotation shaft of the sub-scanning motor 17 and a conveying roller 15 are provided to transmit the rotation of the sub-scanning motor 17 to the conveying roller 15. And a gear 19 fixed to the shaft. 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 12. The subsystem 21 holds four cap means 22 for capping the ejection surface of each head 6 with a holder 23, and holds the holder 23 so as to be swingable with a link member 24 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 6 a of the inkjet head 6 is capped by the cap means 22. When the carriage unit 5 moves toward the printing area, the holder 23 is lifted down in accordance with the movement of the carriage unit 5, and the cap unit 22 is separated from the ejection surface 6 a of the inkjet head 6. The cap means 22 is connected to the suction pump 27 via the suction tube 26, forms an air opening port, and communicates with the atmosphere via the air opening tube and the air opening valve. The suction pump 27 discharges the sucked waste liquid to a waste liquid storage tank (not shown) via a drain tube or the like. Further, on the side of the holder 23, a wiper blade 28, which is a wiping means composed of an elastic member such as a fiber member, a foam member, or rubber, for wiping the ejection surface 6a of the inkjet head 6, is attached to a blade arm 29. Numeral 29 is pivotally supported so as to be pivoted by rotation of a cam which is rotated by driving means (not shown).
[0031]
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, and FIG. 3 is a front sectional view of the ink cartridge.
As shown in FIG. 3, the ink cartridge 7 contains an ink absorber 42 in which ink (aqueous recording liquid) of a required color is absorbed in a cartridge main body 41. The cartridge body 41 is formed by bonding or welding an upper lid member 44 to an upper opening of a case 43 having a wide opening at an 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 body, and absorbs ink after being compressed and inserted into the cartridge main body 41. 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. In the cartridge main body 41, before the loading, the ink supply port 45 is closed, and the case 43 is compressed and deformed by the pressure applied to the wide side wall at the time of handling the cartridge at the time of loading or transportation, or at the time of vacuum packaging. A cap member 50 is mounted to prevent the ink inside from leaking. Further, as shown in FIG. 2, the atmosphere opening port 47 has an oxygen permeability of 100 ml / m 2. ² The above film-like sealing member 55 is adhered to the upper lid member 44 for sealing. In this way, the atmosphere opening port 47 has an oxygen transmission rate of 100 ml / m. ² By sealing with the sealing member 55 described above, the ink cartridge 7 is wrapped under reduced pressure using a wrapping member such as an air-impermeable aluminum laminated film, so that the ink cartridge 7 can be filled with the ink and the ink absorber 42 and the cartridge body 41. Even when 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 body 41 having a high degree of vacuum through the seal member 55, Is discharged into the space between the two, and the degree of deaeration of the ink is improved.
[0032]
FIG. 4 illustrates a configuration example of a recording cartridge (recording unit) including a recording liquid storage unit that stores the aqueous recording liquid of the present invention and a head unit that discharges recording liquid droplets. Hereinafter, the recording unit will be described.
The recording unit 30 is of a serial type, and includes a head 6, an ink tank 33 that stores an aqueous recording liquid (ink) supplied to the head 6, and a lid member 34 that seals the inside of the ink tank 33. The main part is configured. A large number of nozzles 32 for discharging the aqueous recording liquid are formed on the head 6 of the recording unit 30. The recording liquid is guided from the ink tank 33 to a common liquid chamber (not shown) via an ink supply pipe (not shown), and is discharged from the nozzle 32 according to an electric signal from the recording apparatus main body input from the electrode 31. You. The recording unit 30 of this type has a structure suitable for a head that can be manufactured at a low cost due to its configuration, that is, a so-called thermal type or bubble type head that uses thermal energy as a driving power source. The recording liquid of the present invention has improved wettability to a thermal element in a recording method such as a bubble method or a thermal method, so that ejection stability and frequency stability can be obtained even with a small amount of addition and high safety. , Very suitable.
Here, the serial type ink jet recording apparatus as described above has been described. However, the aqueous recording liquid of the present invention has a nozzle having an arbitrary arrangement such as a staggered pattern and having a density equal to or a fraction of the resolution of the target image. It is also possible to apply the present invention to a recording apparatus having a so-called line head, which is integrated into a plurality of recording media and arranged so as to be equal to or larger than the width of the recording medium.
Further, the recording device here may be not only an output printer for a PC or a digital camera but also a device having a complex function combined with a facsimile, a scanner, a telephone, or the like.
[0033]
【Example】
Hereinafter, Examples and Comparative Examples of the present invention will be described, but the present invention is not limited thereto.
In addition, the amount (%) of each component described in Examples is based on weight.
Example 1
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH became 8 to 9. Thereafter, the mixture was concentrated with a membrane filter having an average pore size of 0.2 μm to obtain an ink composition.
[0034]
Direct Blue 199 3.0% by weight
Glycerin 7.0% by weight
1,3-butanediol 28.0% by weight
2,4-diethyl-1,5-pentanediol 4.0% by weight
Deionized water remaining
[0035]
Example 2
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of sodium hydroxide so that the pH became 8 to 9. Thereafter, the mixture was concentrated with a membrane filter having an average pore size of 0.2 μm to obtain an ink composition.
[0036]
Direct Yellow 132 2.5% by weight
Diethylene glycol 15.0% by weight
1,3-butanediol 20.0% by weight
2,4-diethyl-1,5-pentanediol 4.5% by weight
Deionized water remaining
[0037]
Example 3
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH became 8 to 9. Thereafter, the mixture was concentrated with a membrane filter having an average pore size of 0.2 μm to obtain an ink composition.
[0038]
Acid Red 249 3.0% by weight
Glycerin 7.0% by weight
1,3-butanediol 28.0% by weight
2,4-diethyl-1,5-pentanediol 2.5% by weight
Nikko Chemicals Corporation ECTD3NEX 0.5% by weight
(R1: tridecyl group of general formula (1), m: 3, M: Na)
Deionized water remaining
[0039]
Example 4
Except using the following composition, it carried out similarly to Example 1. The ink composition was adjusted with a 10% aqueous solution of lithium hydroxide so that the pH became 8 to 9.
[0040]
Direct Black 168 5.0% by weight
Glycerin 7.0% by weight
1,3-butanediol 28.0% by weight
2,4-diethyl-1,5-pentanediol 2.0% by weight
15% by weight of 2-ethyl-1,3-hexanediol
Deionized water remaining
[0041]
Example 5
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH became 8 to 9. Thereafter, the mixture was concentrated with a membrane filter having an average pore size of 0.2 μm to obtain an ink composition.
[0042]
Direct Black 168 4.0% by weight
Glycerin 7.0% by weight
1,3-butanediol 28.0% by weight
2,4-diethyl-1,5-pentanediol 4.0% by weight
2.0% by weight of 2-pyrrolidone
Deionized water remaining
[0043]
Example 6
A pigment dispersion was prepared according to the following formulation. After premixing the mixture having the following formulation, the mixture was placed in a 1-liter vessel, 900 g of zirconia beads having a diameter of 0.3 mm was added, and the mixture was dispersed for 48 hours using a batch-type tabletop sand mill manufactured by Campe to obtain Pigment Dispersion 1. The average particle size was 102 nm (measured using Microtrac UPA150).
[0044]
Pigment dispersion liquid 1
C. I. Pigment Blue 15: 3 15.0% by weight
Styrene-acrylate-methacrylic acid diethanolamine salt copolymer 3.0% by weight
Deionized water remaining
[0045]
Ink composition 6
Using Pigment Dispersion 1, the pH was adjusted to 8 to 9 with a 10% aqueous solution of sodium hydroxide. Thereafter, the mixture was concentrated with a membrane filter having an average pore diameter of 0.8 μm to obtain an ink composition.
[0046]
Pigment dispersion liquid 1 20.0% by weight
Glycerin 7.0% by weight
1,3-butanediol 28.0% by weight
2,4-diethyl-1,5-pentanediol 2.0% by weight
2,2,4-trimethyl-1,3-pentanediol 2.0% by weight
Deionized water remaining
[0047]
Example 7
A pigment dispersion was prepared according to the following formulation. After premixing the mixture having the following formulation, the mixture was placed in a 1-liter vessel, 900 g of zirconia beads having a diameter of 0.3 mm were added, and the mixture was dispersed for 48 hours using a Campe-made batch type sand mill to obtain Pigment Dispersion Liquid 2. The average particle size was 114 nm (measured using Microtrac UPA150).
[0048]
Pigment dispersion liquid 2
15.0% by weight of carbon black
Styrene-acrylate-methacrylic acid diethanolamine salt copolymer 3.0% by weight
Deionized water remaining
[0049]
Ink composition 7
The pigment dispersion 2 was used and adjusted with a 10% aqueous solution of sodium hydroxide so that the pH became 8 to 9. Thereafter, the mixture was concentrated with a membrane filter having an average pore diameter of 0.8 μm to obtain an ink composition.
[0050]
33.33% by weight of pigment dispersion liquid 2
Glycerin 7.0% by weight
1,3-butanediol 28.0% by weight
Nikko Chemicals Corporation ECTD6NEX 0.5% by weight
(R1: tridecyl group of general formula (1), m: 6, M: Na)
2,4-diethyl-1,5-pentanediol 2.5% by weight
2-pyrrolidone 2% by weight
Deionized water remaining
[0051]
Example 8
In the same manner as in Example 1 except that the following composition was used, an ink composition was prepared by adjusting the pH to 8 with a 10% aqueous solution of lithium hydroxide.
[0052]
Carboxylate-bound carbon black dispersion 33.33% by weight
(Cabot CAB-O-JET 300)
Glycerin 7.0% by weight
1,3-butanediol 28% by weight
2,4-diethyl-1,5-pentanediol 4.0% by weight
Deionized water remaining
[0053]
Example 9
In the same manner as in Example 1 except that the following composition was used, an ink composition was prepared by adjusting the pH to 8 with a 10% aqueous solution of lithium hydroxide.
Sulfonate-bound carbon black dispersion 25% by weight
(Cabot CAB-O-JET 200)
Glycerin 7.0% by weight
1,3-butanediol 28% by weight
2,4-diethyl-1,5-pentanediol 4.0% by weight
Deionized water remaining
[0054]
Comparative Example 1
An ink composition was prepared in the same manner as in Example 1 except that the following composition was used so that the pH was adjusted to 8 to 9 with a 10% aqueous solution of lithium hydroxide.
[0055]
Direct Black 168 4.0% by weight
Glycerin 7.0% by weight
Triethylene glycol 28.0% by weight
Deionized water remaining
[0056]
Comparative Example 2
In the same manner as in Example 1 except that the following composition was used, an ink composition was prepared by adjusting with a 10% aqueous solution of sodium hydroxide so that the pH became 8 to 9.
[0057]
Direct Black 168 4.0% by weight
Glycerin 7.0% by weight
Diethylene glycol 28.0% by weight
2.0% by weight of 2-methyl-2-propyl-1,3-propanediol
Deionized water remaining
[0058]
Comparative Example 3
In the same manner as in Example 1 except that the following composition was used, an ink composition was prepared by adjusting with a 10% aqueous solution of sodium hydroxide so that the pH became 8 to 9.
[0059]
Direct Black 168 4.0% by weight
Glycerin 7.0% by weight
Diethylene glycol 28.0% by weight
2-methyl-2-propyl-1,3-propanediol 4.0% by weight
Deionized water remaining
[0060]
Comparative Example 4
In the same manner as in Example 1 except that the following composition was used, an ink composition was prepared by adjusting the pH to 8 to 9 with a 10% aqueous solution of lithium hydroxide.
[0061]
33.33% by weight of pigment dispersion liquid 2 of Example 7
Glycerin 7.0% by weight
Triethylene glycol 23.0% by weight
Triethylene glycol monobutyl ether 4.0% by weight
Deionized water remaining
[0062]
Next, the following tests were performed on the above-mentioned Examples and Comparative Examples. Table 1 shows the results.
(1) Surface tension of ink
The surface tension of the ink at 25 ° C. was measured using an automatic surface tension meter K10ST manufactured by KRUSS (unit: mN / m 2).
(2) Image clarity
Printing is performed by a piezo-type ink jet printer (IPSIO JET 300 manufactured by Ricoh Co., Ltd.) using My Paper (size: 12 s, air permeability: 16 s) as a recording medium; The distress, image distress, color tone, and density were visually and visually determined by a reflection-type color spectrophotometer (manufactured by X-Rite).
(3) Dryness of image
0.1 kg / cm for the image after printing the solid image on the recording medium ² The time required for the ink to stop transferring to the source paper when the dark paper was pressed with the pressure was measured. If any of the papers dried within 3 seconds, it was judged as Δ.
(4) strikethrough
A solid image was formed on a recording medium such that the density of each ink color measured with a reflection type color spectrophotometer (manufactured by X-Rite) was 1.0. If this image is visually observed from the back side and the boundary between the solid image and the white background is clear and there is a problem when using it for double-sided printing, the boundary between the solid image and the white background is almost unclear and the double-sided printing is performed. In the case of a level which does not cause any trouble even when used, it was judged as 、. In the case where the boundary between the solid image and the white background was completely unclear and there was no problem even when used for double-sided printing, it was judged as ◎.
(5) Scratch
The image formed with each ink on the recording medium is rubbed with a finger, a cloth, an eraser, and a marking pin 30 seconds after printing, and the state after the rubbing is visually observed. And if there was no occurrence, it was evaluated as ○.
(6) Image filling
After drying, the solid image was visually observed. A mark was given when the recording medium was uniformly colored with the ink, and a mark was given when the recording medium was unevenly colored such that the background was visible.
(7) Storage
With the ink set in the ink jet printer, the ink was left at 60 ° C. for 7 days. Thereafter, it was evaluated as “〇” if the ink could be recovered by the cleaning operation of the ink jet printer, and “x” if not possible.
[0063]
[Table 1]

[0064]
As shown in the results of the above table, the aqueous recording liquid of the present invention not only reduces the surface tension, improves the wettability between the ink and the paper surface, and increases the permeation rate to the paper, as well as conventionally known. The image deterioration is extremely small as compared with the case where the permeability is enhanced mainly with a simple surfactant. Also, the penetration rate is almost the same regardless of the type of the coloring agent.
[0065]
【The invention's effect】
According to the present invention, an ink jet printer capable of high-speed printing has a practically sufficient drying property without using a special drying device, and an aqueous recording liquid having no image deterioration such as strikethrough or bleeding of an image. A recording method using this is provided. The aqueous recording liquid of the present invention is suitable for ink jet recording such as a piezo method, an on-demand method such as a thermal method, and a continuous ejection method such as a charge control method, and particularly exhibits excellent characteristics as a color ink for so-called plain paper. , Water-based writing utensils, recorders, and water-based inks for pen plotters.
[Brief description of the drawings]
FIG. 1 is a schematic front view showing a configuration example 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 the ink cartridge before being loaded into a recording apparatus.
FIG. 3 is a front sectional view of the ink cartridge.
FIG. 4 is a diagram illustrating a configuration example of a recording cartridge including a recording liquid storage unit that stores the aqueous recording liquid of the present invention and a head unit that discharges recording droplets.
[Explanation of symbols]
1, 2 side plate
3 Main support guide rod
4 Secondary support guide rod
5 Carriage unit
6 heads
7 Ink cartridge
15 Transport rollers
16 paper
21 Reliability Maintenance and Recovery Mechanism
22 Cap means
23 Holder
24 Link members
28 Wiper blade
29 blade arm
30 Recording unit
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 Atmospheric opening
55 Film seal member

Claims (11)

The ink composition contains at least water, a colorant soluble or dispersible in water, 2,4-diethyl-1,5-pentanediol, a diol derivative having 4 or less carbon atoms, and a water-soluble organic solvent. An aqueous recording liquid, characterized in that: 2. The aqueous recording liquid according to claim 1, wherein 2,4-diethyl-1,5-pentanediol is contained at a ratio of 0.1 to 5% by weight based on the total weight of the ink composition. The aqueous recording liquid according to claim 1, wherein the surfactant is contained in a ratio of 0.01 to 5% by weight based on the total weight of the ink composition. The aqueous recording liquid according to claim 3, wherein a polyoxyethylene alkyl ether acetate represented by the following general formula (1) is used as the surfactant.
_{R1-O- (CH 2 CH 2} O) m-CH 2 COOM ... (1)
(Wherein, R1 represents an alkyl group having 6 to 14 carbon atoms which may be branched, m represents a natural number of 3 to 12, and M represents an alkali metal ion, quaternary ammonium, quaternary phosphonium, or alkanolamine) The aqueous recording liquid further comprises at least one selected from the group consisting of 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. The aqueous recording liquid according to any one of claims 1 to 4. The aqueous recording liquid according to any one of claims 1 to 5, wherein the aqueous recording liquid further contains 2-pyrrolidone. The aqueous recording liquid according to any one of claims 1 to 6, wherein the colorant is a pigment having an average particle size of 50 nm to 200 nm. The aqueous recording liquid according to any one of claims 1 to 7, wherein the colorant is a pigment dispersed in water by a dispersant having a carboxyl group bonded thereto. The aqueous recording liquid according to any one of claims 1 to 7, wherein the colorant is a pigment that is modified by binding a carboxyl group to its surface and can be dispersed in water. The aqueous recording liquid according to any one of claims 1 to 7, wherein the colorant is a pigment that is modified by bonding a sulfonic acid group to its surface and can be dispersed in water. A recording method comprising ejecting the aqueous recording liquid according to any one of claims 1 to 10 as droplets from a fine ejection opening and flying to form an image on a recording medium.

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