JP3880076B2 - Ink, inkjet recording method, recording unit, ink cartridge, and inkjet recording apparatus - Google Patents

Description

（式中、Ａｒ及びＡｒ¹は夫々アリール基又は置換アリール基を示し、Ａｒ及びＡｒ¹の少なくとも１つはＣＯＯＨ基又はＣＯＳＨ基を有する。
Ｊ及びＪ¹は夫々下記一般式（II）、（III）及び（IV）からなる群から選ばれる。
【化６】

（式中、Ｒ⁵は独立的に、Ｈ、アルキル基、置換アルキル基、アルコキシ基、ハロゲン、ＣＮ、ウレイド及びＮＨＣＯＲ⁶から選択される。Ｒ⁶はＨ、アルキル基、置換アルキル基、アリール基、置換アリール基、アラルキル基及び置換アラルキル基から選択される。Ｔはアルキル基を示し、ＷはＨ、ＣＮ、ＣＯＮＲ¹⁰Ｒ¹¹、ピリジウム及びＣＯＯＨから選択される。Ｒ¹⁰及びＲ¹¹は夫々Ｈ、アルキル基及び置換アルキル基から選択される。（ｍ）は炭素数２〜８のアルキレン鎖を示し、ＢはＨ、アルキル基及びＣＯＯＨから選択される。）
Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は夫々Ｈ、アルキル基及び置換アルキル基から選択され、Ｌは２価の有機結合基を示し、ｎは０又は１を示す。Ｘはカルボニル基又は下記一般式（V）、（VI）又は（VII）の構造からなる。
【化７】

（式中、Ｚは、ＯＲ⁷、ＳＲ⁷及びＮＲ⁸Ｒ⁹から選択され、ＹはＨ、Ｃｌ、ＣＮ、ＯＲ⁷、ＳＲ⁷及びＮＲ⁸Ｒ⁹から選択され、ＥはＣｌまたはＣＮである。Ｒ⁷、Ｒ⁸及びＲ⁹は夫々Ｈ、アルケニル基、置換アルケニル基、アルキル基、置換アルキル基、アリール基、置換アリール基、アラルキル基及び置換アラルキル基から選択される。Ｒ⁸及びＲ⁹はこれらが結合された窒素原子と共に５員環又は６員環を形成してもよい。）
但し一般式（Ｉ）で示される化合物がＳＯ₃Ｈ基をもたない場合は、該化合物は少なくとも２つのＣＯＯＨ基又はＣＯＳＨ基から選ばれる基を有し、一般式（Ｉ）で示される化合物がＳＯ₃Ｈ基をもつ場合は、該化合物はＣＯＯＨ基又はＣＯＳＨ基を少なくともＳＯ₃Ｈ基の数と同数有する。）

（式中、Ｒ ₁ は、炭素数１〜４８のアルキル基又は水素原子を表し、Ｒ ₂ は、（ＣＨ ₂ ） _a −Ｘ ₁ 又は水素原子を表し、ａは１〜４の整数とする。Ｒ ₃ は、（ＣＨ ₂ ） _b −Ｘ ₂ 又はＲ ₄ −Ｙ又は水素原子を表し、ｂは１〜４の整数とする。Ｒ ₄ は、炭素数１〜４８のアルキル基又は水素原子を表す。Ｚは、（ＮＲ ₅ Ｃ _q Ｈ _2q ） _c （ＮＨＣ _n Ｈ _2n ） _d を表し、ｑ及びｎは２〜４の整数、ｃ＋ｄは０〜５０の整数とする。Ｙは、（ＮＲ ₆ Ｃ _m Ｈ _2m ） _e （ＮＨＣ _p Ｈ _2p ） _f を表し、ｍ及びｐは２〜４の整数、ｅ＋ｆは０〜５０の整数とする。Ｒ ₅ は、（ＣＨ ₂ ） _g −Ｘ ₃ を表し、ｇは１〜４の整数とする。Ｒ ₆ は、（ＣＨ ₂ ） _h −Ｘ ₄ を表し、ｈは１〜４の整数とする。Ｘ ₁ 、Ｘ ₂ 、Ｘ ₃ 及びＸ ₄ は、夫々、カルボキシル基、カルボキシル基の塩、スルホン基、スルホン基の塩又は水素原子からなる群から選ばれる。又、一般式（ VIII ）の化合物は、カルボキシル基、スルホン基、カルボキシル基の塩及びスルホン基の塩から選ばれるものを少なくとも１つ以上有する。）
【０００７】
【作用】
本発明者等は、水溶性インクによる印字記録物の耐水性の向上の為、様々なインク組成について鋭意検討を行った結果、少なくとも一般式（Ｉ）で示される染料と、ｐＨが４〜１０の範囲で溶解性が最小となるピークを有し、且つ、炭素数３以上のアルキル基、カルボキシル基の塩及びスルホン基の塩からなる群から選ばれる少なくとも１種の基を有する一般式（ VIII ）で示される構造の、第２級アミン、第２級アミンの誘導体、第３級アミン及び第３級アミンの誘導体からなる群より選ばれる少なくとも１種の化合物と、これらを溶解又は分散する液媒体とから少なくともなることを特徴とするインクは、得られる印字記録物が高品位であり、且つ耐水性も良好であるばかりでなく、耐目詰まり性も良好で、更に長期保存に対しても問題の無いインクであることを見い出した。
【０００８】
そのメカニズムは定かではないが、推測の域で述べると、一般式（Ｉ）で示される染料と、ｐＨが４〜１０の範囲で溶解性が最小となるピークを有し、且つ、炭素数３以上のアルキル基、カルボキシル基の塩及びスルホン基の塩からなる群から選ばれる少なくとも１種の基を有する一般式（ VIII ）で示される構造の、第２級アミン、第２級アミンの誘導体、第３級アミン及び第３級アミンの誘導体からなる群より選ばれる少なくとも１種の化合物がインク中では弱く、被記録材上では強くインターラクションをし、夫々の構造若しくは両者の構造的相性から、酸性紙或いは中性紙等の普通紙に対して印字記録物の画像品位及び耐水性を良好にし、且つ耐目詰まり性や長期保存に対しても何ら問題の無いインクが提供できたものと思われる。
【０００９】
【好ましい実施態様】
次に好ましい実施態様を挙げて更に詳しく説明する。
本発明にかかるインクは、一般式（Ｉ）で示される染料と、ｐＨが４〜１０の範囲で溶解性が最小となるピークを有し、且つ、炭素数３以上のアルキル基、カルボキシル基の塩及びスルホン基の塩からなる群から選ばれる少なくとも１種の基を有する一般式（ VIII ）で示される構造の、第２級アミン、第２級アミンの誘導体、第３級アミン及び第３級アミンの誘導体からなる群より選ばれる少なくとも１種の化合物（以下、第２級アミンと略す）と、これらを溶解又は分散する液媒体とから構成されることを特徴とする。
【００１０】
本発明で使用される染料として特に好ましいのは、下記一般式（Ｉ）に示される染料である。
【化８】

（式中、Ａｒ及びＡｒ¹は夫々アリール基又は置換アリール基を示し、Ａｒ及びＡｒ¹の少なくとも１つはＣＯＯＨ基又はＣＯＳＨ基を有する。
Ｊ及びＪ¹は夫々下記一般式（II）、（III）及び（IV）からなる群から選ばれる。
【化９】

（式中、Ｒ⁵は独立的に、Ｈ、アルキル基、置換アルキル基、アルコキシ基、ハロゲン、ＣＮ、ウレイド及びＮＨＣＯＲ⁶から選択される。Ｒ⁶はＨ、アルキル基、置換アルキル基、アリール基、置換アリール基、アラルキル基及び置換アラルキル基から選択される。Ｔはアルキル基を示し、ＷはＨ、ＣＮ、ＣＯＮＲ¹⁰Ｒ¹¹、ピリジウム及びＣＯＯＨから選択される。Ｒ ¹⁰ 及びＲ ¹¹ は夫々Ｈ、アルキル基 及び置換アルキル基から選択される。（ｍ）は炭素数２〜８のアルキレン鎖を示し、ＢはＨ、アルキル基及びＣＯＯＨから選択される。）
Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は夫々Ｈ、アルキル基及び置換アルキル基から選択され、Ｌは２価の有機結合基を示し、ｎは０又は１を示す。Ｘはカルボニル基又は下記一般式（V）、（VI）又は（VII）の構造からなる。
【化１０】

（式中、Ｚは、ＯＲ⁷、ＳＲ⁷及びＮＲ⁸Ｒ⁹から選択され、ＹはＨ、Ｃｌ、ＣＮ、ＯＲ ⁷ 、ＳＲ ⁷ 及びＮＲ ⁸ Ｒ ⁹ から選択され、ＥはＣｌまたはＣＮである。Ｒ⁷、Ｒ⁸及びＲ⁹は夫々Ｈ、アルケニル基、置換アルケニル基、アルキル基、置換アルキル基、アリール基、置換アリール基、アラルキル基及び置換アラルキル基から選択される。Ｒ⁸及びＲ⁹はこれらが結合された窒素原子と共に５員環又は６員環を形成してもよい。）
但し一般式（Ｉ）で示される化合物がＳＯ₃Ｈ基をもたない場合は、該化合物は少なくとも２つのＣＯＯＨ基又はＣＯＳＨ基から選ばれる基を有し、
一般式（Ｉ）で示される化合物がＳＯ₃Ｈ基をもつ場合は、該化合物はＣＯＯＨ基又はＣＯＳＨ基を少なくともＳＯ₃Ｈ基の数と同数有する。）
【００１１】
この中で、特に好ましい染料を以下に示すが、本発明はこれらに限定されるものではない。
【００１２】
【化１１】

【００１３】
【化１２】

【００１４】
【化１３】

【００１５】
【化１４】

【００１６】
【化１５】

【００１７】
本発明にかかるインクに使用される、第２級アミン、第２級アミンの誘導体、第３級アミン、第３級アミンの誘導体及び夫々の複合化合物から選ばれる少なくとも１種の化合物であり、且つアルキル基、カルボキシル基、カルボキシル基の塩、スルホン基及びスルホン基の塩からなる群から選ばれる少なくとも１種の基を有する化合物は、図７に示す様に、インクのｐＨが４〜１０の範囲で溶解性が最小となるピークを有する化合物であるのが好ましい。
即ち、ｐＨが４〜１０の範囲で溶解性が最小となるピークを有する化合物をインク中に添加すると、酸性紙及び中性紙に画像形成した場合、インクと大気との界面で不溶化膜を形成する為、耐水性を向上させる効果が顕著になる。
尚、複合化合物とは、１分子中に、例えば、第２級アミン基と第３級アミン基とを同時に有するものをいう。
【００１８】
この様な化合物の中で、特に好ましいのは、下記一般式（VIII）で示される化合物である。
【００１９】
【化１６】

（式中、Ｒ₁は、炭素数１〜４８のアルキル基又は水素原子を表し、Ｒ₂は、（ＣＨ₂）_a−Ｘ₁又は水素原子を表し、ａは１〜４の整数とする。Ｒ₃は、（ＣＨ₂）_b−Ｘ₂又はＲ₄−Ｙ又は水素原子を表し、ｂは１〜４の整数とする。Ｒ₄は、炭素数１〜４８のアルキル基又は水素原子を表す。Ｚは、（ＮＲ₅Ｃ_lＨ_2l）_c（ＮＨＣ_nＨ_2n）_dを表し、ｌ（エル）及びｎは２〜４の整数、ｃ＋ｄは０〜５０の整数とする。Ｙは、（ＮＲ₆Ｃ_mＨ_2m）_e（ＮＨＣ_pＨ_2p）_fを表し、ｍ及びｐは２〜４の整数、ｅ＋ｆは０〜５０の整数とする。Ｒ₅は、（ＣＨ₂）_g−Ｘ₃を表し、ｇは１〜４の整数とする。Ｒ₆は、（ＣＨ₂）_h−Ｘ₄を表し、ｈは１〜４の整数とする。Ｘ₁、Ｘ₂、Ｘ₃及びＸ₄は、夫々、カルボキシル基、カルボキシル基の塩、スルホン基、スルホン基の塩又は水素原子からなる群から選ばれる。又、一般式（VIII）の化合物は、カルボキシル基、カルボキシル基の塩、スルホン基及びスルホン基の塩からなる群から選ばれるものを少なくとも１以上有する。）
【００２０】
又、一般式（VIII）の化合物において、インク性能の安定性等を考えると、特にＸ₁、Ｘ₂、Ｘ₃及びＸ₄が、夫々、カルボキシル基の塩、スルホン基の塩又は水素原子からなる群から選ばれることが好ましい。
この理由は、Ｘ₁、Ｘ₂、Ｘ₃及びＸ₄が、夫々、カルボキシル基又はスルホン基から選ばれると、一般式（VIII）の化合物は、環状化合物を形成し、インクの性能や信頼性を低下させ易くなる為である。以下に、一般式（VIII）に含まれる好ましい化合物を列挙したが、本発明はこれらの化合物に限定されるものではなく、又、これらの化合物は２種以上を同時に使用することも出来る。
【００２１】
（化合物１）
【化１７】

（化合物２）
【化１８】

（化合物３）
【化１９】

【００２２】
（化合物４）
【化２０】

（化合物５）
【化２１】

【００２３】
（化合物６）
【化２２】

【００２４】
（化合物７） Ｃ₁₅Ｈ₃₁(ＮＨＣ₂Ｈ₄)₂ＮＨＣＨ₂ＣＯＯＮａ
（化合物８） Ｃ₁₅Ｈ₃₁ＮＨＣ₂Ｈ₄ＣＯＯＬｉ
（化合物９） Ｃ₃Ｈ₇(ＮＨＣ₂Ｈ₄)₂ＮＨＣＨ₂ＣＯＯＮａ
（化合物１０）Ｃ₁₂Ｈ₂₅ＮＨＣ₂Ｈ₄ＣＯＯＮａ
（化合物１１）Ｃ₁₂Ｈ₂₅(ＮＨＣ₂Ｈ₄)ＮＨＣＨ₂ＣＯＯＬｉ
【００２５】
（化合物１２）Ｃ₁₂Ｈ₂₅(ＮＨＣ₂Ｈ₄)ＮＨＣ₂Ｈ₄ＳＯ₃Ｌｉ
（化合物１３）Ｃ₁₅Ｈ₃₁(ＮＨＣ₂Ｈ₄)ＮＨＣＨ₂ＳＯ₃Ｎａ
（化合物１４）Ｃ₂₀Ｈ₄₁(ＮＨＣ₂Ｈ₄)ＮＨＣＨ₂ＳＯ₃ＮＨ₄
（化合物１５）Ｃ₁₅Ｈ₃₁(ＮＨＣ₂Ｈ₄)₂ＮＨＣ₂Ｈ₄ＣＯＯＮＨ₄
（化合物１６）Ｃ₂₅Ｈ₅₁(ＮＨＣ₂Ｈ₄)₃ＮＨＣＨ₂ＳＯ₃Ｌｉ
（化合物１７）Ｃ₁₅Ｈ₃₁(ＮＨＣ₂Ｈ₄)ＮＨＣＨ₂ＳＯ₃Ｈ・Ｎ(ＣＨ₂ＣＨ₃)₃
【００２６】
（化合物１８）Ｃ₁₀Ｈ₂₁(ＮＨＣ₂Ｈ₄)₃ＮＨＣ₂Ｈ₄ＣＯＯＨ・ＮＨ（ＣＨ₂ＣＨ₃）₂
（化合物１９）Ｃ₁₂Ｈ₂₅(ＮＨＣ₂Ｈ₄）₂ＮＨＣＨ₂ＣＯＯＮＨ₄
（化合物２０）Ｃ₅Ｈ₁₁(ＮＨＣ₂Ｈ₄)₂ＮＨＣＨ₂ＣＯＯＮａ
（化合物２１）Ｃ₇Ｈ₁₅(ＮＨＣ₂Ｈ₄)₂Ｃ₂Ｈ₄ＣＯＯＮａ
（化合物２２）Ｃ₁₂Ｈ₂₅(ＮＨＣ₂Ｈ₄)₄ＮＨＣＨ₂ＣＯＯＮａ
【００２７】
（化合物２３）
【化２３】

（化合物２４）
【化２４】

【００２８】
（化合物２５）Ｃ₁₂Ｈ₂₅ＮＨＣ₃Ｈ₆ＮＨＣＨ₂ＣＯＯＮＨ₄
（化合物２６）Ｃ₁₂Ｈ₂₅ＮＨＣ₃Ｈ₆ＮＨＣ₂Ｈ₄ＣＯＯＮａ
（化合物２７）Ｃ₈Ｈ₁₇Ｎ(ＣＨ₃)Ｃ₂Ｈ₄Ｎ(ＣＨ₃)Ｃ₂Ｈ₄ＮＨＣ₂Ｈ₄ＣＯＯＮａ
（化合物２８）Ｃ₁₂Ｈ₂₅ＮＨＣ₃Ｈ₆ＮＨＣ₂Ｈ₄ＣＯＯＬｉ
【００２９】
（化合物２９）
【化２５】

（化合物３０）
【化２６】

【００３０】
本発明にかかるインクを構成する上記した様な特定の染料及び化合物を、溶解又は分散する液媒体としては、水と水溶性有機溶剤との混合物を使用するのが好ましい。又、本発明で使用される具体的な水溶性有機溶剤の例としては、例えば、ジメチルホルムアミド、ジメチルアセトアミド等のアミド類；アセトン等のケトン類；テトラヒドロフラン、ジオキサン等のエーテル類；ポリエチレングリコール、ポリプロピレングリコール等のポリアルキレングリコール類；エチレングリコール、プロピレングリコール、ブチレングリコール、トリエチレングリコール、１，２，６−ヘキサントリオール、チオジグリコール、ヘキシレングリコール、ジエチレングリコール等のアルキレン基が２〜６個の炭素原子を含むアルキレングリコール類；グリセリン；エチレングリコールモノメチル（又はエチル）エーテル、ジエチレングリコールモノメチル（又はエチル）エーテル、トリエチレングリコールモノメチル（又はエチル）エーテル等の多価アルコールの低級アルキルエーテル類；Ｎ−メチル−２−ピロリドン、１，３−ジメチル−２−イミダゾリジノン、トリエタノールアミン、スルホラン、ジメチルサルフォキサイド、２−ピロリドン、ε−カプロラクタム等の環状アミド化合物及びスクシンイミド等のイミド化合物等が挙げられる。
【００３１】
又、本発明にかかるインク中には、インク中での染料の溶解安定性を向上させる為に、各種の添加剤を含有させることが好ましい。即ち、インク中に、アンモニア、アルキルアミン等の揮発性塩基成分が含まれているが、これらは経時的に揮発し、次第に染料の溶解安定性が悪くなる為、アルカリ供給体として尿素又は尿素誘導体を含有させることが好ましい。尿素又は尿素誘導体のインク中の含有量は、０．０１〜２０重量％の範囲、好ましくは、０．１〜１５重量％の範囲である。
【００３２】
又、インク中に２価の金属イオンが存在する場合に、ヒーターがこげる等のインクシェットに特有な問題が生じる。この様に、コゲを防止する手段として、ＥＤＴＡや、塩酸、硫酸、酢酸、リン酸、或いはマレイン酸、コハク酸及びクエン酸等のカルボン酸化合物等の酸性成分を使用する。上記酸性成分のインク中での含有量は、特に制限はないが、０．０１〜１０ｗｔ％の範囲、より好ましくは０．１〜３ｗｔ％の範囲である。
【００３３】
又、本発明のインクは、染料の溶解安定性等を目的として、インク中に１価の金属イオンを含有させることも好ましい態様である。本発明のインクに使用される１価の金属イオンとして好ましいものとしては、ナトリウム及びリチウムが挙げられる。
又、１価の金属イオンのインク中における含有量は、０．０１〜１０．０重量％の範囲、好ましくは、０．１〜５．０重量％、より好ましくは０．１〜３．０重量％とする。尚、これらの１価の金属イオンは、染料のカウンターイオンとして含有させてもよい。
【００３４】
更に、本発明にかかるインクは、インクジェット記録方法に用いる場合、上記の添加剤等でインクのｐＨを９以上とするのが好ましい。即ち、インクジェット記録方法は、水性ボールペン等とは異なり、被記録材とインクとの接触がなく、文房具の様に記録時にペン圧を加筆することにより目詰りを解決することが出来ない為、インクのｐＨを９以上に保つことにより、インクの溶解性を良好にするのが好ましい。
尚、本発明にかかるインクは、上記成分の他にも、必要に応じて界面活性剤、防錆剤、防腐剤、防カビ剤、酸化防止剤、還元防止剤、蒸発促進剤、キレート化剤、水溶性ポリマー等の種々の添加剤を含有させてもよい。
【００３５】
前記した様な、遊離酸の状態で一般式（Ｉ）で表される染料のインクへの添加量は、用途、目的、染料種、インク組成によるところが大きいが、０．１〜１５重量％の範囲、好ましくは０．１〜１０重量％の範囲である。
【００３６】
又、一般式（VIII）で示される様な化合物のインクへの添加量についても同様に、用途、目的、色材種、インク組成によるところが大きいが、０．０１〜２０重量％の範囲、好ましくは、０．１〜１０重量％の範囲である。
又、染料と一般式（VIII）で示される様な化合物とのインク中での比率は、構造的相性、両者間でのインターラクション等から、インク中に含まれる染料と一般式（VIII）で示される化合物の比率は、１：３〜８：１の範囲とするのが好ましい。
【００３７】
染料及び化合物を溶解又は分散する液媒体である水溶性有機溶剤の含有量は、一般にはインクの全重量に対して重量％で１％〜４０％が好ましく、より好ましくは３％〜３０％の範囲である。
又、インク中の水の含有量は、３０〜９５重量％の範囲で使用される。３０重量％より少ないと色材である染料の溶解性等が悪くなり、インクの粘度も高くなる為好ましくない。一方、９５重量％より多いと蒸発成分が多すぎて、十分な固着特性を満足することが出来ない。
【００３８】
本発明にかかるインクは、一般の水性筆記用具としても使用出来るが、熱エネルギーによるインクの発泡現象によりインクを吐出させるタイプのインクジェット記録方法に適用する場合に特に好適であり、吐出が極めて安定となり、サテライトドットの発生等が生じないという特徴がある。但し、この場合には、熱的な物性値（例えば、比熱、熱膨張係数、熱伝導率等）を調整する場合もある。
更に、本発明にかかるインクは普通紙等に記録した場合の印字記録物のインクの耐水性の問題を解決すると同時に、インクジェット用ヘッドに対するマッチングを良好にする面から、インク自体の物性として２５℃における表面張力が３０〜６８ｄｙｎｅ／ｃｍ、粘度が１５ｃＰ以下、好ましくは１０ｃＰ以下、より好ましくは５ｃＰ以下に調整されることが望ましい。
従って、上記物性にインクを調整し、普通紙における問題を解決する為には、本発明にかかるインク中に含有される水分量としては５０重量％以上９８重量％以下、好ましくは６０重量％以上９５重量％以下とされるのが好適である。
【００３９】
本発明にかかるインクを用いて記録を行うのに好適な方法及び装置としては、記録ヘッドの室内のインク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るインクジェット記録方法及びインクジェット記録装置が挙げられる。
【００４０】
その装置の主要部であるヘッド構成例を図１、図２及び図３に示す。
ヘッド１３はインクを通す溝１４を有するガラス、セラミックス又はプラスチック板等と、感熱記録に用いられる発熱ヘッド１５（図ではヘッドが示されているが、これに限定されるものではない）とを接着して得られる。発熱ヘッド１５は酸化シリコン等で形成される保護膜１６、アルミニウム電極１７−１、１７−２、ニクロム等で形成される発熱抵抗体層１８、蓄熱層１９、アルミナ等の放熱性のよい基盤２０とによりなっている。
【００４１】
インク２１は吐出オリフィス（微細孔）２２まできており、圧力Ｐによりメニスカス２３を形成している。
今、電極１７−１、１７−２に電気信号が加わると、発熱ヘッド１５のｎで示される領域が急激に発熱し、ここに接しているインク２１に気泡が発生し、その圧力でメニスカス２３が突出し、インク２１が吐出し、オリフィス２２より記録小滴２４となり、被記録材２５に向かって飛翔する。
図３には図１に示すヘッドを多数並べたマルチヘッドの外観図を示す。該マルチヘッドはマルチ溝２６を有するガラス板２７と、図１に説明したものと同様な発熱ヘッド２８を密着して製作されている。尚、図１は、インク流路に沿ったヘッド１３の断面図であり、図２は図１のＡ−Ｂ線での切断図である。
【００４２】
図４に、かかるヘッドを組み込んだインクジェット記録装置の一例を示す。
図４において、６１はワイピング部材としてのブレードであり、その一端はブレード保持部材によって保持されて固定端となり、カンチレバーの形態をなす。ブレード６１は記録ヘッドによる記録領域に隣接した位置に配設され、又、本例の場合、記録ヘッドの移動経路中に突出した形態で保持される。６２はキャップであり、ブレード６１に隣接するホームポジションに配設され、記録ヘッドの移動方向と垂直な方向に移動して吐出口面と当接し、キャッピングを行う構成を備える。更に６３はブレード６１に隣接して設けられるインク吸収体であり、ブレード６１と同様、記録ヘッドの移動経路中に突出した形態で保持される。上記ブレード６１、キャップ６２、吸収体６３によって吐出回復部６４が構成され、ブレード６１及び吸収体６３によってインク吐出口面の水分、塵埃等の除去が行われる。
【００４３】
６５は吐出エネルギー発生手段を有し、吐出口を配した吐出口面に対向する被記録材にインクを吐出して記録を行う記録ヘッドであり、６６は記録ヘッド６５を搭載して記録ヘッド６５の移動を行う為のキャリッジである。キャリッジ６６はガイド軸６７と慴動可能に係合し、キャリッジ６６の一部はモータ６８によって駆動されるベルト６９と接続（不図示）している。これによりキャリッジ６６はガイド軸６７に沿った移動が可能となり、記録ヘッド６５による記録領域及びその隣接した領域の移動が可能となる。
５１は被記録材を挿入する為の給紙部、５２は不図示のモータにより駆動される紙送りローラである。これらの構成によって記録ヘッドの吐出口面と対向する位置へ被記録材が給紙され、記録が進行するにつれて排紙ローラ５３を配した排紙部へ排紙される。
【００４４】
上記構成において記録ヘッド６５が記録終了等でホームポジションに戻る際、ヘッド回復部６４のキャップ６２は記録ヘッド６５の移動経路から退避しているが、ブレード６１は移動経路中に突出している。この結果、記録ヘッド６５の吐出口面がワイピングされる。尚、キャップ６２が記録ヘッド６５の吐出面に当接してキャッピングを行う場合、キャップ６２は記録ヘッドの移動経路中に突出する様に移動する。
記録ヘッド６５がホームポジションから記録開始位置へ移動する場合、キャップ６２及びブレード６１は上述したワイピング時の位置と同一の位置にある。この結果、この移動においても記録ヘッド６５の吐出口面はワイピングされる。
上述の記録ヘッドのホームポジションへの移動は、記録終了時や吐出回復時ばかりでなく、記録ヘッドが記録の為に記録領域を移動する間に所定の間隔で記録領域に隣接したホームポジションへ移動し、この移動に伴って上記ワイピングが行われる。
【００４５】
図５は、ヘッドにインク供給部材、例えばチューブを介して供給されるインクを収容したインクカートリッジの一例を示す図である。ここで４０は供給用インクを収容したインク収容部、例えば、インク袋であり、その先端にはゴム製の栓４２が設けられている。この栓４２に針（不図示）を挿入することにより、インク袋４０中のインクをヘッドに供給可能ならしめる。４４は廃インクを受容する吸収体である。インク収容部としては、インクとの接液面がポリオレフィン、特にポリエチレンで形成されているものが本発明にとって好ましい。本発明で使用されるインクジェット記録装置としては、上記の如きヘッドとインクカートリッジとが別体となったものに限らず、図６に示す如きそれらが一体になったものにも好適に用いられる。
【００４６】
図６において、７０は記録ユニットであって、この中にはインクを収容したインク収容部、例えば、インク吸収体が収納されており、かかるインク吸収体中のインクが複数のオリフィスを有するヘッド部７１からインク滴として吐出される構成になっている。インク吸収体の材料としては、ポリウレタン、セルロース又はポリビニルアセテートを用いることが本発明にとって好ましい。７２は記録ユニット内部を大気に連通させる為の大気連通口である。この記録ユニット７０は、図４で示す記録ヘッドに代えて用いられるものであって、キャリッジ６６に対して着脱自在になっている。
【００４７】
【実施例】
次に、実施例及び比較例を挙げて、本発明を更に具体的に説明する。尚、文中、部及び％とあるのは、特に断りのない限り重量基準である。
【００４８】
実施例１〜実施例５
下記に示す各成分を混合し、十分撹拌して溶解後、ポアサイズが０．４５μｍのフロロポアフィルター（商品名：住友電工（株）製）にて加圧濾過し、本発明のインクを夫々調整した。又、夫々の化合物の塩成分でｐＨを約９．５に調整した。
【００４９】
実施例１のインク組成
・化合物２５ ３部
・チオジグリコール １０部
・水 ７９部
・染料１ ２．５部
・硫酸アンモニウム ０．５部
・尿素 ５部
【００５０】
実施例２のインク組成
・化合物２０ ２部
・２−ピロドリン １０部
・水 ７９部
・染料２ ３部
・尿素 ５部
・亜硫酸ナトリウム １部
【００５１】
実施例３のインク組成
・化合物１５ １部
・チオジグリコール ６部
・水 ８２．５部
・染料４ ３部
・アンモニア ０．５部
・尿素 ７部
【００５２】
実施例４のインク組成
・化合物２４ ３部
・ジエチレングリコール ８部
・水 ８１部
・染料１ ２部
・酢酸ナトリウム １部
・尿素 ５部
【００５３】
実施例５のインク組成
・化合物２５ ３部
・チオジグリコール １０部
・水 ８４部
・染料１ ２．５部
・硫酸アンモニウム ０．５部
【００５４】
比較例１〜比較例５
実施例１〜実施例３の組成について、夫々の組成から一般式（VIII）で示される化合物を除き、その不足分を純水で補ったものを夫々比較例１〜比較例３のインクとした。又、実施例４の化合物の代わりに、ジメチルドデシルベタインに置き換えたものを比較例４に、実施例５の化合物の代わりにトリプロパノールアミンに置き換えたものを比較例５とした。
【００５５】
【評価】
次に、上記で得られた実施例１〜実施例５と比較例１〜比較例５のインクを用い、インクジェット記録装置として発熱素子をインクの吐出エネルギー源として利用したインクオンデマンド型インクジェットプリンターを使用して印字試験を行い、（１）耐水性、（２）耐目詰まり性、（３）印字品位及び（４）長期保存性の評価を下記の基準に従って夫々行った。又、得られた結果を表１に示す。
尚、上記インクジェット記録装置の印字条件としては、駆動電圧２６Ｖ、発熱抵抗体の抵抗値１５０Ω及び周波数４ｋＨｚで行った。
【００５６】
（評価方法及び評価基準）
（１）耐水性（Ａ）
プリンターに所定のインクを充填して、市販の酸性紙に英数文字及びベタ部を印字した後、プリントを停止し、印字物を１時間以上放置後、印字濃度をマクベスＲＤ９１５（商品名：マクベス社製）にて測定を行う。その後、印字物を水で満たした容器に３分間浸した後、放置して、自然乾燥させ再度印字濃度を測定し、印字物濃度の残存率を求め、耐水性の評価とした。
◎：印字物濃度の残存率が９０％以上。
○：印字物濃度の残存率が８０％以上〜８９％以下。
△：印字物濃度の残存率が６６％以上〜７９％以下。
×：印字物濃度の残存率が６５％以下。
【００５７】
（２）耐水性（Ｂ）
プリンターに所定のインクを充填して、市販の中性紙に英数文字及びベタ部を印字した後、プリントを停止し、印字物を１時間以上放置後、印字濃度をマクベスＲＤ９１５（商品名：マクベス社製）にて測定を行う。その後、印字物を水で満たした容器に３分間浸した後、放置して、自然乾燥させ再度印字濃度を測定し、印字物濃度の残存率を求め、耐水性の評価とした。
◎：印字物濃度の残存率が９０％以上。
○：印字物濃度の残存率が８０％以上〜８９％以下。
△：印字物濃度の残存率が６６％以上〜７９％以下。
×：印字物濃度の残存率が６５％以下。
【００５８】
（３）目詰まり性（固着回復性）の評価
プリンターを３５℃の恒温槽に１ヵ月放置し、その後室温に２４時間放置し、回復操作（ポンピングによる吸引操作）を行った後印字して、下記基準にて評価した。
○：回復操作５回以内で正常な印字状態に戻る。
△：回復操作６〜１０回で正常な印字状態に戻る。
×：回復操作６〜１０回で不吐出又は印字の乱れがある。
【００５９】
（４）印字品位の評価（Ａ）
プリンターで市販の酸性紙に英数文字を印字し、印字物を１時間以上放置した後、顕微鏡及び目視で文字のシャープさや文字より発生するヒゲ状の滲みの度合いを評価した。
◎：文字がシャープでヒゲ状の滲みがない。
○：文字がシャープであるが、ヒゲ状の滲みが少し発生。
△：文字にシャープさがない。又はヒゲ状の滲みが少し多い。
×：文字にシャープさがなく、ヒゲ状の滲みも多い。
【００６０】
（５）印字品位の評価（Ｂ）
プリンターで市販の中性紙に英数文字を印字し、印字物を１時間以上放置した後、顕微鏡及び目視で文字のシャープさや文字より発生するヒゲ状の滲みの度合いを評価した。
◎：文字がシャープでヒゲ状の滲みがない。
○：文字がシャープであるが、ヒゲ状の滲みが少し発生。
△：文字にシャープさがない。又はヒゲ状の滲みが少し多い。
×：文字にシャープさがなく、ヒゲ状の滲みも多い。
【００６１】
（６）長期保存性の評価
夫々のインクを密封したビン容器に入れて、５０℃の環境下に３か月間放置し、そのインクを濾紙で濾過して、濾紙上の凝集物の有無を目視で観察し、下記の基準で評価した。
○：凝集物がない。
△：凝集物が僅かにみられる。
×：凝集物が多くある。
【００６２】
【表１】
表１ 評価結果

【００６３】
【発明の効果】
以上の様に、本発明によれば、一般オフィス等で使用されている酸性紙及び中性紙等のいわゆる普通紙に対して印字記録をした場合、印字記録物の印字品位等に悪影響を及ぼすことなく、印字記録物の耐水性を向上させ、且つ耐目詰まり性、定着性及び耐コゲ性に優れたインクを提供することが出来る。
更に、本発明によれば、長期の保存にも安定であり、インクジェット記録システムに用いても何ら問題のない信頼性の高い記録を行い得るインクを提供することが出来る。
【図面の簡単な説明】
【図１】インクジェット記録装置のヘッド部の縦断面図である。
【図２】インクジェット記録装置のヘッド部の横断面図である。
【図３】図１に示したヘッドをマルチ化したヘッドの外観斜視図である。
【図４】インクジェット記録装置の一例を示す斜視図である。
【図５】インクカートリッジの縦断面図である。
【図６】記録ユニットの斜視図である。
【図７】本発明で使用される化合物のｐＨと溶解性の関係を示す図である。
【符号の説明】
６１：ワイピング部材
６２：キャップ
６３：インク吸収体
６４：吐出回復部
６５：記録ヘッド
６６：キャリッジ[0001]
[Industrial application fields]
The present invention is ink,IInkjet recording method, Recording unit, ink cartridgeas well asInkjet recording deviceMore specifically, the printed matter is excellent in water resistance when printing on so-called plain paper such as acid paper and neutral paper used in general offices, etc., and performs high-quality recording. Ink,IInkjet recording method, Recording unit, ink cartridgeas well asInkjet recording deviceAbout.
[0002]
[Prior art]
Conventionally, water-based inks and ink-jet inks for writing instruments (fountain pens, sign pens, water-based ballpoint pens, etc.) have been reported in various compositions. In particular, in recent years, there has been a growing demand for improved water resistance of printed matter on plain paper such as copy paper, report paper, notebooks, and stationery paper that are commonly used in offices. For example, JP-A-2-296878 Japanese Laid-Open Patent Publication No. 2-25576 and Japanese Laid-Open Patent Publication No. 2-255576 propose to improve the water resistance of a printed matter by adding a polyamine to a water-based ink composition.
[0003]
[Problems to be solved by the invention]
However, in inks such as those described above, the mechanism for improving water resistance is largely due to salt increase on the hydrophilic base of the dye, so clogging resistance, ink stability, and dye solubility in the ink. Is a problem.
Therefore, in the ink as described above, for example, a dissolution stabilizer is included in the ink for the purpose of improving the stability of the ink and the solubility of the dye in the ink. In this case, since a large amount of a dissolution stabilizer must be added, the image quality and fixability of a printed matter formed using such an ink are deteriorated. In particular, in ink jet recording, since the fixability of ink recorded on a recording material such as plain paper is largely due to natural penetration and evaporation of the recording material, it is preferable to include a large amount of a dissolution stabilizer in the ink. Absent. In addition, when the dissolution stabilizer is used in an ink jet recording method, there is a problem in that kogation occurs and reliability is lowered.
[0004]
Japanese Patent Laid-Open No. 3-91577 proposes a method for improving water resistance by using a dye having a carboxyl group and having the carboxyl group converted to an ammonium salt or a volatile substituted ammonium salt. .
However, even in this case, although the dissolution stability of the ink at the initial stage is good, since the ammonia or substituted ammonia volatilizes with time, the dissolution stability of the dye and clogging resistance gradually deteriorate. Furthermore, the variation in water resistance level depending on the paper type is also a problem.
In this way, the ink is stable over a long period of time, and when an image is formed using such an ink, the image has high quality and good water resistance, and further, it has high anti-clogging and fixing properties. No good ink has yet been proposed to the world.
[0005]
Accordingly, the object of the present invention is to achieve excellent print image quality and water resistance when printing is performed on so-called plain paper such as acid paper and neutral paper used in general offices. An ink having excellent anti-clogging and kogation resistance and no problem for long-term storage, an ink jet recording method using the ink, and such an ink. The purpose is to provide the equipment used.
[0006]
[Means for solving problems]
  The above object is achieved by the present invention described below. That is, the present invention relates to a dye represented by the following general formula (I) in a free acid state,It has a peak with minimum solubility in the range of pH 4 to 10 and has 3 or more carbon atomsAlkyl group, MosquitoOf the ruboxyl groupSaltedAnd at least one group selected from the group consisting of salts of sulfone groupsThe following general formula ( VIII Of the structure indicated by, Secondary amines, derivatives of secondary amines, tertiary aminesas well asTertiary amine inductionBodyAn ink, an ink jet recording method, a recording unit, an ink cartridge, and an ink jet recording apparatus comprising at least one compound selected from the group consisting of the above and a liquid medium in which these are dissolved or dispersed.
[Chemical formula 5]

(Wherein Ar and Ar¹Each represents an aryl group or a substituted aryl group, Ar and Ar¹At least one of them has a COOH group or a COSH group.
  J and J¹Are each selected from the group consisting of the following general formulas (II), (III) and (IV).
[Chemical 6]

(Wherein R^FiveAre independently H, alkyl group, substituted alkyl group, alkoxy group, halogen, CN, ureido and NHCOR.⁶Selected from. R⁶Is selected from H, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group and a substituted aralkyl group. T represents an alkyl group, W represents H, CN, CONR^TenR¹¹, Pyridium and COOH. R^TenAnd R¹¹Are each selected from H, an alkyl group and a substituted alkyl group. (M) represents an alkylene chain having 2 to 8 carbon atoms, and B is selected from H, an alkyl group and COOH. )
  R¹, R², R^ThreeAnd R^FourAre each selected from H, an alkyl group and a substituted alkyl group, L represents a divalent organic linking group, and n represents 0 or 1. X consists of a carbonyl group or the structure of the following general formula (V), (VI) or (VII).
[Chemical 7]

(Where Z is OR⁷, SR⁷And NR⁸R⁹And Y is H, Cl, CN, OR⁷, SR⁷And NR⁸R⁹And E is Cl or CN. R⁷, R⁸And R⁹Are each selected from H, alkenyl group, substituted alkenyl group, alkyl group, substituted alkyl group, aryl group, substituted aryl group, aralkyl group and substituted aralkyl group. R⁸And R⁹May form a 5- or 6-membered ring with the nitrogen atom to which they are bonded. )
  However, the compound represented by the general formula (I) is SO._ThreeWhen there is no H group, the compound has a group selected from at least two COOH groups or COSH groups, and the compound represented by the general formula (I) is SO 2._ThreeIn the case of having an H group, the compound contains at least a SOOH group or a COSH group._ThreeIt has the same number as the number of H groups. )

(Wherein R ₁ Represents an alkyl group having 1 to 48 carbon atoms or a hydrogen atom, and R ₂ (CH ₂ ) _a -X ₁ Or represents a hydrogen atom, and a is an integer of 1 to 4. R _Three (CH ₂ ) _b -X ₂ Or R _Four -Y or a hydrogen atom is represented, and b is an integer of 1 to 4. R _Four Represents an alkyl group having 1 to 48 carbon atoms or a hydrogen atom. Z is (NR _Five C _q H _2q ) _c (NHC _n H _2n ) _d Q and n are integers of 2 to 4, and c + d is an integer of 0 to 50. Y is (NR ₆ C _m H _2m ) _e (NHC _p H _2p ) _f M and p are integers of 2 to 4, and e + f is an integer of 0 to 50. R _Five (CH ₂ ) _g -X _Three And g is an integer of 1 to 4. R ₆ (CH ₂ ) _h -X _Four And h is an integer of 1 to 4. X ₁ , X ₂ , X _Three And X _Four Are each selected from the group consisting of a carboxyl group, a carboxyl group salt, a sulfone group, a sulfone group salt, or a hydrogen atom. The general formula ( VIII ) Has at least one selected from a carboxyl group, a sulfone group, a salt of a carboxyl group and a salt of a sulfone group. )
[0007]
[Action]
  As a result of intensive studies on various ink compositions in order to improve the water resistance of a printed matter with a water-soluble ink, the present inventors have at least a dye represented by the general formula (I),It has a peak with minimum solubility in the range of pH 4 to 10 and has 3 or more carbon atomsAlkyl group, MosquitoOf the ruboxyl groupSaltedAnd at least one group selected from the group consisting of salts of sulfone groupsGeneral formula ( VIII Of the structure indicated by, Secondary amines, derivatives of secondary amines, tertiary aminesas well asTertiary amine inductionBodyAn ink characterized by comprising at least one compound selected from the group consisting of the above and a liquid medium in which these are dissolved or dispersed has a high-quality printed recording material and has good water resistance. The ink was found not only to have clogging resistance but also to have a problem for long-term storage.
[0008]
  The mechanism is not clear, but in the area of speculation, the dye represented by the general formula (I),It has a peak with minimum solubility in the range of pH 4 to 10 and has 3 or more carbon atomsAlkyl group, MosquitoOf the ruboxyl groupSaltedAnd at least one group selected from the group consisting of salts of sulfone groupsGeneral formula ( VIII Of the structure indicated by, Secondary amines, derivatives of secondary amines, tertiary aminesas well asTertiary amine inductionBodyAt least one compound selected from the group consisting of these groups is weak in the ink, interacts strongly on the recording material, and the plain paper such as acid paper or neutral paper from each structure or the structural compatibility of both. On the other hand, it seems that the image quality and water resistance of the printed matter were improved, and an ink having no problem with respect to clogging resistance and long-term storage could be provided.
[0009]
[Preferred embodiment]
  The present invention will be described in more detail with reference to preferred embodiments.
  The ink according to the present invention includes a dye represented by the general formula (I),It has a peak with minimum solubility in the range of pH 4 to 10 and has 3 or more carbon atomsAlkyl group, MosquitoOf the ruboxyl groupSaltedAnd at least one group selected from the group consisting of salts of sulfone groupsGeneral formula ( VIII Of the structure indicated by, Secondary amines, derivatives of secondary amines, tertiary aminesas well asTertiary amine inductionBodyIt is characterized by comprising at least one compound selected from the group consisting of the following (hereinafter abbreviated as secondary amine) and a liquid medium in which these are dissolved or dispersed.
[0010]
Particularly preferred as the dye used in the present invention is a dye represented by the following general formula (I).
[Chemical 8]

(Wherein Ar and Ar¹Each represents an aryl group or a substituted aryl group, Ar and Ar¹At least one of the COOHBaseOr COSHBaseHave
J and J¹Are each selected from the group consisting of the following general formulas (II), (III) and (IV).
[Chemical 9]

(Wherein R^FiveAre independently H, alkyl group, substituted alkyl group, alkoxy group, halogen, CN, ureido and NHCOR.⁶Selected from. R⁶Is selected from H, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group and a substituted aralkyl group. T represents an alkyl group, W represents H, CN, CONR^TenR¹¹, Pyridium and COOH.R ^Ten And R ¹¹ Are H and alkyl groups respectively. And a substituted alkyl group.(M) represents an alkylene chain having 2 to 8 carbon atoms, and B is selected from H, an alkyl group and COOH.. )
R¹, R², R^ThreeAnd R^FourAre each selected from H, an alkyl group and a substituted alkyl group, L represents a divalent organic linking group, and n represents 0 or 1. X consists of a carbonyl group or the structure of the following general formula (V), (VI) or (VII).
Embedded image

(Where Z is OR⁷, SR⁷And NR⁸R⁹Y is selected from H, Cl, CN, OR ⁷ , SR ⁷ And NR ⁸ R ⁹ And E is ClOrCNInThe R⁷, R⁸And R⁹Are each selected from H, alkenyl group, substituted alkenyl group, alkyl group, substituted alkyl group, aryl group, substituted aryl group, aralkyl group and substituted aralkyl group..R⁸And R⁹Form a 5- or 6-membered ring with the nitrogen atom to which they are attached.May be. )
However,Formula (I)Compound represented byIs SO_ThreeWhen there is no H group,The compound isHaving a group selected from at least two COOH groups or COSH groups;
oneGeneral formula (I)Compound represented byIs SO_ThreeIf it has an H group,The compound isCOOH group or COSH groupTheAt least SO_ThreeSame as the number of H groupsNumerousTo do.)
[0011]
Among these, particularly preferred dyes are shown below, but the present invention is not limited thereto.
[0012]
Embedded image

[0013]
Embedded image

[0014]
Embedded image

[0015]
Embedded image

[0016]
Embedded image

[0017]
And at least one compound selected from a secondary amine, a secondary amine derivative, a tertiary amine, a tertiary amine derivative and a complex compound thereof, which is used in the ink according to the present invention; The compound having at least one group selected from the group consisting of an alkyl group, a carboxyl group, a salt of a carboxyl group, a sulfone group and a salt of a sulfone group has an ink pH in the range of 4 to 10, as shown in FIG. It is preferable that the compound has a peak with a minimum solubility.
That is, when a compound having a peak that has a minimum solubility in a pH range of 4 to 10 is added to the ink, an insolubilized film is formed at the interface between the ink and the atmosphere when an image is formed on acidic paper and neutral paper. Therefore, the effect of improving water resistance becomes remarkable.
In addition, a composite compound means what has a secondary amine group and a tertiary amine group simultaneously in 1 molecule, for example.
[0018]
Among such compounds, a compound represented by the following general formula (VIII) is particularly preferable.
[0019]
Embedded image

(Wherein R₁Represents an alkyl group having 1 to 48 carbon atoms or a hydrogen atom, and R₂(CH₂)_a-X₁Or represents a hydrogen atom, and a is an integer of 1 to 4. R_Three(CH₂)_b-X₂Or R_Four-Y or a hydrogen atom is represented, and b is an integer of 1 to 4. R_FourRepresents an alkyl group having 1 to 48 carbon atoms or a hydrogen atom. Z is (NR_FiveC_lH_2l)_c(NHC_nH_2n)_d, L (el) and n are integers of 2 to 4, and c + d is an integer of 0 to 50. Y is (NR₆C_mH_2m)_e(NHC_pH_2p)_fM and p are integers of 2 to 4, and e + f is an integer of 0 to 50. R_Five(CH₂)_g-X_ThreeAnd g is an integer of 1 to 4. R₆(CH₂)_h-X_FourAnd h is an integer of 1 to 4. X₁, X₂, X_ThreeAnd X_FourAre each selected from the group consisting of a carboxyl group, a carboxyl group salt, a sulfone group, a sulfone group salt or a hydrogen atom. The compound of the general formula (VIII) has at least one selected from the group consisting of a carboxyl group, a salt of a carboxyl group, a sulfone group and a salt of a sulfone group. )
[0020]
Further, considering the stability of the ink performance in the compound of the general formula (VIII), in particular X₁, X₂, X_ThreeAnd X_FourAre preferably selected from the group consisting of a carboxyl group salt, a sulfone group salt or a hydrogen atom.
The reason for this is X₁, X₂, X_ThreeAnd X_FourHowever, when each selected from a carboxyl group or a sulfone group, the compound of the general formula (VIII) forms a cyclic compound, which tends to lower the performance and reliability of the ink. The preferred compounds included in the general formula (VIII) are listed below, but the present invention is not limited to these compounds, and two or more of these compounds can be used simultaneously.
[0021]
(Compound 1)
Embedded image

(Compound 2)
Embedded image

(Compound 3)
Embedded image

[0022]
(Compound 4)
Embedded image

(Compound 5)
Embedded image

[0023]
(Compound 6)
Embedded image

[0024]
(Compound 7) C₁₅H₃₁(NHC₂H_Four)₂NHCH₂COONa
(Compound 8) C₁₅H₃₁NHC₂H_FourCOOLi
(Compound 9) C_ThreeH₇(NHC₂H_Four)₂NHCH₂COONa
(Compound 10) C₁₂H_{twenty five}NHC₂H_FourCOONa
(Compound 11) C₁₂H_{twenty five}(NHC₂H_Four) NHCH₂COOLi
[0025]
(Compound 12) C₁₂H_{twenty five}(NHC₂H_FourNHC₂H_FourSO_ThreeLi
(Compound 13) C₁₅H₃₁(NHC₂H_Four) NHCH₂SO_ThreeNa
(Compound 14) C₂₀H₄₁(NHC₂H_Four) NHCH₂SO_ThreeNH_Four
(Compound 15) C₁₅H₃₁(NHC₂H_Four)₂NHC₂H_FourCOONH_Four
(Compound 16) C_{twenty five}H₅₁(NHC₂H_Four)_ThreeNHCH₂SO_ThreeLi
(Compound 17) C₁₅H₃₁(NHC₂H_Four) NHCH₂SO_ThreeH ・ N (CH₂CH_Three)_Three
[0026]
(Compound 18) C_TenH_{twenty one}(NHC₂H_Four)_ThreeNHC₂H_FourCOOH · NH (CH₂CH_Three)₂
(Compound 19) C₁₂H_{twenty five}(NHC₂H_Four)₂NHCH₂COONH_Four
(Compound 20) C_FiveH₁₁(NHC₂H_Four)₂NHCH₂COONa
(Compound 21) C₇H₁₅(NHC₂H_Four)₂C₂H_FourCOONa
(Compound 22) C₁₂H_{twenty five}(NHC₂H_Four)_FourNHCH₂COONa
[0027]
(Compound 23)
Embedded image

(Compound 24)
Embedded image

[0028]
(Compound 25) C₁₂H_{twenty five}NHC_ThreeH₆NHCH₂COONH_Four
(Compound 26) C₁₂H_{twenty five}NHC_ThreeH₆NHC₂H_FourCOONa
(Compound 27) C₈H₁₇N (CH_Three) C₂H_FourN (CH_Three) C₂H_FourNHC₂H_FourCOONa
(Compound 28) C₁₂H_{twenty five}NHC_ThreeH₆NHC₂H_FourCOOLi
[0029]
(Compound 29)
Embedded image

(Compound 30)
Embedded image

[0030]
As a liquid medium for dissolving or dispersing the above-mentioned specific dyes and compounds constituting the ink according to the present invention, it is preferable to use a mixture of water and a water-soluble organic solvent. Specific examples of the water-soluble organic solvent used in the present invention include, for example, amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; ethers such as tetrahydrofuran and dioxane; polyethylene glycol, polypropylene Polyalkylene glycols such as glycols; carbons having 2 to 6 alkylene groups such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol Alkylene glycols containing atoms; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl ( Is ethyl) ether and other lower alkyl ethers of polyhydric alcohols; N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide, 2-pyrrolidone And cyclic amide compounds such as ε-caprolactam and imide compounds such as succinimide.
[0031]
The ink according to the present invention preferably contains various additives in order to improve the dissolution stability of the dye in the ink. That is, although volatile base components such as ammonia and alkylamine are contained in the ink, these are volatilized over time, and the dissolution stability of the dye gradually deteriorates. It is preferable to contain. The content of urea or urea derivative in the ink is in the range of 0.01 to 20% by weight, preferably in the range of 0.1 to 15% by weight.
[0032]
In addition, when divalent metal ions are present in the ink, a problem peculiar to the ink shell such as a heater burns out. As described above, acidic components such as EDTA, hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, or carboxylic acid compounds such as maleic acid, succinic acid, and citric acid are used as means for preventing kogation. The content of the acidic component in the ink is not particularly limited, but is in the range of 0.01 to 10 wt%, more preferably in the range of 0.1 to 3 wt%.
[0033]
In addition, in the ink of the present invention, it is also a preferable aspect that a monovalent metal ion is contained in the ink for the purpose of dissolution stability of the dye. Preferable monovalent metal ions used in the ink of the present invention include sodium and lithium.
The content of monovalent metal ions in the ink is in the range of 0.01 to 10.0% by weight, preferably 0.1 to 5.0% by weight, more preferably 0.1 to 3.0%. Weight%. These monovalent metal ions may be contained as dye counter ions.
[0034]
Furthermore, when the ink according to the present invention is used in an ink jet recording method, the pH of the ink is preferably 9 or more with the above-described additives. In other words, unlike the water-based ballpoint pen and the like, the ink jet recording method has no contact between the recording material and the ink, and the clogging cannot be solved by applying the pen pressure at the time of recording like a stationery. By keeping the pH of the ink at 9 or more, it is preferable to improve the solubility of the ink.
In addition to the above-described components, the ink according to the present invention includes a surfactant, a rust inhibitor, a preservative, a fungicide, an antioxidant, a reduction inhibitor, an evaporation accelerator, and a chelating agent as necessary. Various additives such as a water-soluble polymer may be contained.
[0035]
As described above, the amount of the dye represented by the general formula (I) in the state of free acid to the ink largely depends on the purpose, purpose, dye type, and ink composition, but is 0.1 to 15% by weight. The range is preferably 0.1 to 10% by weight.
[0036]
Similarly, the amount of the compound represented by the general formula (VIII) added to the ink is largely dependent on the purpose, purpose, color material type, and ink composition, but is preferably in the range of 0.01 to 20% by weight. Is in the range of 0.1 to 10% by weight.
In addition, the ratio of the dye and the compound represented by the general formula (VIII) in the ink is determined by the structural compatibility, the interaction between the two, the dye contained in the ink and the general formula (VIII). The ratio of the compounds shown is preferably in the range of 1: 3 to 8: 1.
[0037]
The content of the water-soluble organic solvent that is a liquid medium in which the dye and the compound are dissolved or dispersed is generally preferably 1% to 40%, more preferably 3% to 30% by weight with respect to the total weight of the ink. It is a range.
Further, the water content in the ink is used in the range of 30 to 95% by weight. If it is less than 30% by weight, the solubility of the dye, which is a coloring material, is deteriorated, and the viscosity of the ink is increased. On the other hand, if it exceeds 95% by weight, there are too many evaporation components, and sufficient fixing properties cannot be satisfied.
[0038]
The ink according to the present invention can be used as a general water-based writing instrument, but is particularly suitable when applied to an ink jet recording method in which ink is ejected due to the foaming phenomenon of ink due to thermal energy, and the ejection becomes extremely stable. There is a feature that no satellite dot is generated. In this case, however, thermal property values (for example, specific heat, thermal expansion coefficient, thermal conductivity, etc.) may be adjusted.
Furthermore, the ink according to the present invention solves the problem of water resistance of the ink of the printed matter when recorded on plain paper or the like, and at the same time, the physical property of the ink itself is 25 ° C. It is desirable to adjust the surface tension at 30 to 68 dyne / cm and the viscosity to 15 cP or less, preferably 10 cP or less, more preferably 5 cP or less.
Therefore, in order to adjust the ink to the above physical properties and solve the problem in plain paper, the amount of water contained in the ink according to the present invention is 50% by weight to 98% by weight, preferably 60% by weight or more. It is preferable that the content be 95% by weight or less.
[0039]
As a method and apparatus suitable for performing recording using the ink according to the present invention, an ink jet recording method in which thermal energy corresponding to a recording signal is applied to ink in a recording head chamber and droplets are generated by the thermal energy. And an ink jet recording apparatus.
[0040]
An example of a head configuration which is a main part of the apparatus is shown in FIGS.
The head 13 is formed by bonding a glass, ceramic or plastic plate having a groove 14 through which ink passes and a heat generating head 15 (the head is shown in the figure, but is not limited to this) used for thermal recording. Is obtained. The heat generating head 15 includes a protective film 16 formed of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heat generating resistor layer 18 formed of nichrome or the like, a heat storage layer 19, and a base 20 with good heat dissipation such as alumina. It is due to.
[0041]
The ink 21 has a discharge orifice (fine hole) 22, and a meniscus 23 is formed by the pressure P.
Now, when an electrical signal is applied to the electrodes 17-1 and 17-2, the region indicated by n of the heat generating head 15 rapidly generates heat, bubbles are generated in the ink 21 in contact therewith, and the meniscus 23 is generated by the pressure. Protrudes and ink 21 is ejected to form recording droplets 24 from the orifice 22 and fly toward the recording material 25.
FIG. 3 shows an external view of a multi-head in which a large number of heads shown in FIG. 1 are arranged. The multi-head is manufactured by adhering a glass plate 27 having multi-grooves 26 and a heating head 28 similar to that described in FIG. 1 is a cross-sectional view of the head 13 along the ink flow path, and FIG. 2 is a cross-sectional view taken along line AB in FIG.
[0042]
FIG. 4 shows an example of an ink jet recording apparatus incorporating such a head.
In FIG. 4, reference numeral 61 denotes a blade as a wiping member. One end of the blade 61 is held by a blade holding member to become a fixed end, and forms a cantilever. The blade 61 is disposed at a position adjacent to the recording area of the recording head, and in this example, is held in a form protruding in the moving path of the recording head. Reference numeral 62 denotes a cap, which is disposed at a home position adjacent to the blade 61 and has a configuration in which it moves in a direction perpendicular to the moving direction of the recording head and comes into contact with the ejection port surface to perform capping. Further, reference numeral 63 denotes an ink absorber provided adjacent to the blade 61 and, like the blade 61, is held in a form protruding in the moving path of the recording head. The blade 61, the cap 62, and the absorber 63 constitute a discharge recovery portion 64, and the blade 61 and the absorber 63 remove water, dust, and the like from the ink discharge port surface.
[0043]
Reference numeral 65 denotes a recording head that has discharge energy generating means and performs recording by discharging ink onto a recording material facing the discharge port surface on which the discharge ports are arranged. Reference numeral 66 denotes a recording head 65 having the recording head 65 mounted thereon. It is a carriage for performing the movement. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 (not shown) driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording area and its adjacent area can be moved by the recording head 65.
Reference numeral 51 denotes a paper feed unit for inserting a recording material, and 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection port surface of the recording head, and is discharged to a paper discharge portion provided with a paper discharge roller 53 as recording progresses.
[0044]
In the above configuration, when the recording head 65 returns to the home position due to the end of recording or the like, the cap 62 of the head recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. As a result, the ejection port surface of the recording head 65 is wiped. When the cap 62 is in contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving path of the recording head.
When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are in the same position as the above-described wiping position. As a result, the ejection port surface of the recording head 65 is wiped even during this movement.
The above-mentioned movement of the recording head to the home position is not only at the end of recording or at the time of recovery of ejection, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves through the recording area for recording. Then, the wiping is performed with this movement.
[0045]
FIG. 5 is a diagram illustrating an example of an ink cartridge that stores ink supplied to the head via an ink supply member, for example, a tube. Reference numeral 40 denotes an ink container, for example, an ink bag, which contains ink for supply, and a rubber plug 42 is provided at the tip thereof. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the head. Reference numeral 44 denotes an absorber that receives waste ink. As the ink containing portion, it is preferable for the present invention that the liquid contact surface with the ink is formed of polyolefin, particularly polyethylene. The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, but is preferably used in an apparatus in which they are integrated as shown in FIG.
[0046]
In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage portion that stores ink, for example, an ink absorber is stored, and the ink in the ink absorber has a plurality of orifices. 71 is ejected as ink droplets. Ink absorber materials include polyurethane, cellulose or polyvinyl acetate.TateIs preferred for the present invention. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. The recording unit 70 is used in place of the recording head shown in FIG. 4 and is detachable from the carriage 66.
[0047]
【Example】
Next, the present invention will be described more specifically with reference to examples and comparative examples. In the text, “part” and “%” are based on weight unless otherwise specified.
[0048]
Examples 1 to 5
Each component shown below is mixed, dissolved sufficiently by stirring, and then filtered under pressure with a fluoropore filter (trade name: manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 0.45 μm to adjust the ink of the present invention. did. Moreover, pH was adjusted to about 9.5 with the salt component of each compound.
[0049]
Ink composition of Example 1
Compound 25 3 parts
・ Thiodiglycol 10 parts
・ Water 79 parts
・ 2.5 parts of dye 1
・ Ammonium sulfate 0.5 parts
・ Urea 5 parts
[0050]
Ink composition of Example 2
Compound 20 2 parts
・ 2-Pyrodrine 10 parts
・ Water 79 parts
・ Dye 2 3 parts
・ Urea 5 parts
・ Sodium sulfite 1 part
[0051]
Ink composition of Example 3
Compound 15 1 part
・ Thiodiglycol 6 parts
・ Water 82.5 parts
・ Dye 4 3 parts
・ Ammonia 0.5 part
・ Urea 7 parts
[0052]
Ink composition of Example 4
Compound 24 3 parts
・ Diethylene glycol 8 parts
・ 81 parts of water
・ Dye 1 2 parts
・ Sodium acetate 1 part
・ Urea 5 parts
[0053]
Ink composition of Example 5
Compound 25 3 parts
・ Thiodiglycol 10 parts
・ 84 parts of water
・ 2.5 parts of dye 1
・ Ammonium sulfate 0.5 parts
[0054]
Comparative Examples 1 to 5
Regarding the compositions of Examples 1 to 3, inks of Comparative Examples 1 to 3 were prepared by removing the compound represented by the general formula (VIII) from each composition and supplementing the deficiency with pure water. . Further, in place of the compound of Example 4, dimethyldodecylbetaine was replaced by Comparative Example 4, and in place of the compound of Example 5, tripropanolamine was replaced by Comparative Example 5.
[0055]
[Evaluation]
Next, an ink-on-demand type ink jet printer that uses the inks of Examples 1 to 5 and Comparative Examples 1 to 5 obtained above and uses a heating element as an ink ejection energy source as an ink jet recording apparatus. A printing test was performed, and (1) water resistance, (2) clogging resistance, (3) printing quality, and (4) long-term storage stability were evaluated according to the following criteria. The obtained results are shown in Table 1.
The printing conditions of the ink jet recording apparatus were a drive voltage of 26 V, a resistance value of the heating resistor of 150Ω, and a frequency of 4 kHz.
[0056]
(Evaluation method and evaluation criteria)
(1) Water resistance (A)
After filling the printer with the prescribed ink, printing alphanumeric characters and solid parts on commercially available acid paper, stop printing, leave the printed matter for more than 1 hour, then set the print density to Macbeth RD915 (trade name: Macbeth Measured at a manufacturer. Then, after immersing the printed matter in a container filled with water for 3 minutes, the printed matter was left to dry naturally, and the printing density was measured again to obtain the residual ratio of the printed matter density, and the water resistance was evaluated.
A: The residual ratio of the printed matter density is 90% or more.
○: Residual rate of printed matter density is 80% to 89%.
Δ: Residual rate of printed matter density is 66% to 79%.
X: Residual ratio of printed matter density is 65% or less.
[0057]
(2) Water resistance (B)
After filling the printer with predetermined ink and printing alphanumeric characters and solid parts on commercially available neutral paper, the printing is stopped, and the printed matter is left for more than 1 hour, and then the print density is set to Macbeth RD915 (trade name: Measurement is performed with Macbeth. Then, after immersing the printed matter in a container filled with water for 3 minutes, the printed matter was left to dry naturally, and the printing density was measured again to obtain the residual ratio of the printed matter density, and the water resistance was evaluated.
A: The residual ratio of the printed matter density is 90% or more.
○: Residual rate of printed matter density is 80% to 89%.
Δ: Residual rate of printed matter density is 66% to 79%.
X: Residual ratio of printed matter density is 65% or less.
[0058]
(3) Evaluation of clogging (fixing recovery)
The printer was left in a constant temperature bath at 35 ° C. for 1 month, then left at room temperature for 24 hours, and after performing a recovery operation (suction operation by pumping), printing was performed and evaluated according to the following criteria.
○: Normal printing state is restored within 5 recovery operations.
Δ: The normal printing state is restored after 6 to 10 recovery operations.
X: There is no ejection or printing disorder after 6 to 10 recovery operations.
[0059]
(4) Evaluation of print quality (A)
Alphanumeric characters were printed on commercially available acidic paper with a printer, and the printed matter was allowed to stand for 1 hour or more. Then, the sharpness of the characters and the degree of whiskers generated from the characters were evaluated with a microscope and visually.
A: The letters are sharp and there is no whiskers.
○: Characters are sharp, but some whiskers are generated.
Δ: The character is not sharp. Or there is a little more whiskers.
X: Characters are not sharp and there are many whiskers.
[0060]
(5) Evaluation of print quality (B)
Alphanumeric characters were printed on a commercially available neutral paper with a printer, and the printed matter was allowed to stand for 1 hour or more, and then the sharpness of the characters and the degree of whiskers generated from the characters were evaluated with a microscope and visually.
A: The letters are sharp and there is no whiskers.
○: Characters are sharp, but some whiskers are generated.
Δ: The character is not sharp. Or there is a little more whiskers.
X: Characters are not sharp and there are many whiskers.
[0061]
(6) Evaluation of long-term storage
Place each ink in a sealed bottle container and leave it in an environment of 50 ° C. for 3 months. Filter the ink with filter paper and visually observe the presence of aggregates on the filter paper. evaluated.
○: There is no aggregate.
Δ: Slightly aggregated.
X: There are many aggregates.
[0062]
[Table 1]
Table 1 Evaluation results

[0063]
【The invention's effect】
As described above, according to the present invention, when printing is recorded on so-called plain paper such as acid paper and neutral paper used in general offices, the print quality of the printed matter is adversely affected. Therefore, it is possible to provide an ink that improves the water resistance of the printed matter and is excellent in clogging resistance, fixing property, and kogation resistance.
Furthermore, according to the present invention, it is possible to provide an ink that is stable for long-term storage and can perform highly reliable recording without any problem even when used in an ink jet recording system.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a head portion of an ink jet recording apparatus.
FIG. 2 is a cross-sectional view of a head portion of the ink jet recording apparatus.
FIG. 3 is an external perspective view of a head in which the head shown in FIG.
FIG. 4 is a perspective view illustrating an example of an ink jet recording apparatus.
FIG. 5 is a longitudinal sectional view of an ink cartridge.
FIG. 6 is a perspective view of a recording unit.
FIG. 7 is a graph showing the relationship between the pH and solubility of a compound used in the present invention.
[Explanation of symbols]
61: Wiping member
62: Cap
63: Ink absorber
64: Discharge recovery part
65: Recording head
66: Carriage

Claims (33)

A dye represented by the following general formula (I) in the form of the free acid, pH has a peak solubility is minimized in the range of 4 to 10, and, alkyl group having 3 or more carbon atoms, mosquito carboxyl group the structure represented by the following general formula (VIII) with at least one group selected from the group consisting of salts of Shio及 beauty sulfone group, secondary amine, derivatives of secondary amines, tertiary amines and the ink comprising at least one compound chosen from the inductive member or Ranaru group tertiary amine, and a liquid medium dissolving or dispersing these

(In the formula, Ar and Ar ¹ each represent an aryl group or a substituted aryl group, and at least one of Ar and Ar ¹ has a COOH group or a COSH group.
J and J ¹ are each selected from the group consisting of the following general formulas (II), (III) and (IV).

Wherein R ⁵ is independently selected from H, alkyl group, substituted alkyl group, alkoxy group, halogen, CN, ureido and NHCOR ^6. R ⁶ is H, alkyl group, substituted alkyl group, aryl group , A substituted aryl group, an aralkyl group and a substituted aralkyl group, T represents an alkyl group, W is selected from H, CN, CONR ¹⁰ R ¹¹ , pyridium and COOH, and R ¹⁰ and R ¹¹ are each H (M) represents an alkylene chain having 2 to 8 carbon atoms, and B is selected from H, an alkyl group and COOH.)
R ¹ , R ² , R ³ and R ⁴ are each selected from H, an alkyl group and a substituted alkyl group, L represents a divalent organic linking group, and n represents 0 or 1. X consists of a carbonyl group or the structure of the following general formula (V), (VI) or (VII).

Wherein Z is selected from OR ⁷ , SR ⁷ and NR ⁸ R ⁹ , Y is selected from H, Cl, CN, OR ⁷ , SR ⁷ and NR ⁸ R ⁹ , and E is Cl or CN .R ^7, R ⁸ and R ⁹ are each H, alkenyl group, substituted alkenyl group, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, .R ⁸ and R ⁹ is selected from aralkyl and substituted aralkyl groups May form a 5- or 6-membered ring with the nitrogen atom to which they are attached.
However, when the compound represented by the general formula (I) does not have an SO ₃ H group, the compound has at least two groups selected from COOH groups or COSH groups, and is represented by the general formula (I). When has an SO ₃ H group, the compound has at least as many COOH groups or COSH groups as the number of SO ₃ H groups. )

(In the formula, R ₁ represents an alkyl group having 1 to 48 carbon atoms or a hydrogen atom, R ₂ represents (CH ₂ ) _a -X ₁ or a hydrogen atom, and a represents an integer of 1 to 4. R ₃ represents (CH ₂ ) _b —X ₂ or R ₄ —Y or a hydrogen atom, and b represents an integer of 1 to _4. R ₄ represents an alkyl group having 1 to 48 carbon atoms or a hydrogen atom. Z represents (NR ₅ C _q H _2q ) _c (NHC _n H _2n ) _d , q and n are integers of 2 to 4, c + d is an integer of 0 to 50. Y is (NR ₆ C represents _{m H 2m) e (NHC p} H 2p) f, m and p are integer of 2 to 4, .R ₅ is e + f is an integer of 0 to 50 represents (CH _{2) g} -X _3, g is an integer of 1 to 4. R ₆ represents (CH ₂ ) _h —X ₄ and h is an integer of 1 to 4. X ₁ , X ₂ , X ₃ and X ₄ are each Carboxyl group, carboxyl group salt, sulfo Group is selected from the group consisting of salt or a hydrogen atom of the sulfonic group. The compounds of general formula (VIII), at least one which is selected carboxyl group, a sulfonic group, a salt of salt of a carboxyl group and a sulfonic group Have more.)   The ink according to claim 1, wherein the dye represented by formula (I) has a sulfone group as a water-soluble group and has at least the same number of carboxyl groups as the sulfone group.   The ink according to claim 1, wherein the dye represented by formula (I) does not have a sulfone group and has at least two carboxyl groups.   The ink according to claim 1, wherein the dye represented by formula (I) has at least three carboxyl groups. The ink according to claim 1, wherein at least one of Ar and Ar ^{1 in} the dye represented by formula (I) has a structure having at least one carboxyl group. The ink according to claim 1, wherein each of Ar and Ar ^{1 in} the dye represented by formula (I) has a structure having at least one carboxyl group. The ink according to claim 1, wherein each of Ar and Ar ^{1 in} the dye represented by formula (I) has a structure having at least two carboxyl groups. The ink according to claim 1, wherein each of Ar and Ar ^{1 in} the dye represented by formula (I) has a structure having a dicarboxyphenyl group. In the dye represented by the general formula (I), X is a structure represented by the general formula (V), and Z is NHC ₂ H ₄ OH, N (C ₂ H ₄ OH) ₂ , NHR (R is The ink according to claim 1, wherein the ink is selected from alkyl group having 1 to 6 carbon atoms) or morpholino. Wherein the compound represented by formula (VIII), according to claim 1, X _1, X _2, X ₃ and X ₄ is selected from the group consisting of each salt of a carboxyl group, salts of sulfonic group and a hydrogen atom ink.   The ink according to claim 1, further comprising a volatile base component.   The ink according to claim 1, further comprising a volatile base component and a monovalent metal ion. The ink of claim 1 1 or claim 1 2 volatile base component is ammonia or alkyl amines. Monovalent ink according to claim 1 2 metal ion is sodium ion or a lithium ion. The ink according to any one of claims 1,1 1 and 1 2, including urea and urea derivatives. The ink according to any one of claims 1,1 1 and 1 2 pH is 9 or more. As kogation agents, EDTA, hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, maleic acid, ink according to any one of claims 1,1 1 and 1 2 containing either succinic acid and citric acid. The ink according to any one of claims 1 to 17 , wherein the ink is for inkjet. 19. An ink jet recording method, wherein recording is performed on a recording medium by discharging the ink according to claim 18 from an orifice in accordance with a recording signal. The ink jet recording method according to claim 19 , wherein the ink is ejected by applying thermal energy to the ink. A recording unit comprising: an ink containing portion containing the ink according to claim 18; and a head portion for discharging the ink. Recording unit according to claim 2 1 head portion is a head for discharging ink by applying thermal energy to the ink. Ink storage portion, a recording unit according to claim 2 1 or 2 2 containing an ink absorbing member therein. Ink absorber, the recording unit according to claim 2 3 polyurethane, formed by cellulose or polyvinyl acetate. Ink cartridge, characterized by comprising an ink container portion containing the ink according to any one of claims 1 to 18. The ink cartridge according to claim 25 , wherein the ink containing portion has a liquid contact surface with ink formed of polyolefin. 19. An ink jet recording apparatus comprising a recording unit having an ink containing portion containing ink and a head portion for discharging the ink, wherein the ink is the ink according to claim 18. Inkjet recording device. Head portion, an ink jet recording apparatus according to claim 2 7 ink thermal energy is applied to by a head for discharging ink. The ink jet recording apparatus according to claim 27 or 28 , wherein the ink containing portion contains an ink absorber. 30. The ink jet recording apparatus according to claim 29 , wherein the ink absorber is formed of polyurethane, cellulose, or polyvinyl acetate. An ink jet recording apparatus comprising: a recording head for ejecting ink; an ink cartridge having an ink containing portion that contains ink; and an ink supply unit for supplying ink from the ink cartridge to the recording head. an ink jet recording apparatus wherein the ink is an ink according to claim 1 8. Recording head, an ink jet recording apparatus according to claim 3 1 ink thermal energy is applied to it is a head for discharging ink. An ink jet recording apparatus according to claim 3 1 or 3 2 in which the ink accommodating portion has a surface in contact with ink formed of polyolefin.

Images