JP4522648B2 - Black ink for ink jet recording, ink jet recording method, ink cartridge and ink jet recording apparatus using the same - Google Patents

Description

【００２３】
【化２】

【００２４】
更に、ポリビニルエーテルの繰り返し単位数（上記（II−ａ）〜（II−ｅ）においては、ｍ、ｎ、ｌ）は、それぞれ独立に、１〜１０，０００であることが好ましい。また、その合計が（上記（II−ａ）〜（II−ｅ）においては、ｍ＋ｎ＋ｌ）、１０〜２０，０００であることがより好ましい。数平均分子量は、５００〜２０，０００，０００が好ましく、１，０００〜５，０００，０００がより好ましく、２，０００〜２，０００，０００が最も好ましい。
【００２５】
このような高分子分散剤がインク中に占める割合としては、インク全質量に対して、０．１〜２０質量％が好ましく、０．５〜１０質量％がより好ましい。また、高分子分散剤と水不溶性色材とのインク中における含有比率は、固形分質量比で好ましくは高分子分散剤：水不溶性色材＝１：１００〜２：１であると、インクの吐出安定性や保存安定性が向上する。
【００２６】
（水溶性有機溶剤）
本発明のインクジェット記録用ブラックインクに使用する水溶性有機溶剤としては、水溶性の有機溶剤であれば制限なく使用することができ、２種以上の水溶性有機溶剤の混合溶剤としても使用できる。このような混合溶剤として使用する場合は、混合した場合に液状であれば、固体の水溶性有機化合物が含有されていてもよい。
【００２７】
なかでも、水溶性有機溶剤が、高分子分散剤の親水性ブロック部の溶解性パラメータに対して、０．０〜＋１０．０（Ｊ／ｃｍ³）^1/2の範囲にある溶解性パラメータを有する水溶性有機溶剤であると、インクジェットヘッドのノズルの目詰まりがより発生しにくくなり好ましい。この溶解性パラメータ（δ（Ｊ／ｃｍ³）^1/2）は、溶剤の凝集エネルギー密度の平方根として表わされ、δ＝（ΔＥ／Ｖ）^1/2（式中、ΔＥは溶剤のモル蒸発熱、Ｖは溶媒のモル体積）の式から算出される溶剤の溶解性を示す溶剤固有の値である。例えば、水はδ＝４７．０、エタノールはδ＝２５．７、ヘキサンはδ＝１４．９である。また、高分子分散剤の溶解性パラメータ（δ）は、高分子分散剤の無限溶解度又は最高膨潤度を与える溶剤の溶解性パラメータ＝高分子の溶解性パラメータとする実験的に算出した値や、高分子分散剤の官能基の分子凝集エネルギーから算出した値である。高分子分散剤及び溶剤の溶解性パラメータ（δ）を官能基の分子凝集エネルギーから算出する方法は、δ＝（ΔＥ／Ｖ）^1/2＝（ΣΔｅ_i／ΣΔｖ_i）^1/2（式中、ΔＥはそれぞれのモル蒸発熱、Ｖはそれぞれのモル体積、Δｅ_iはそれぞれの原子団の蒸発エネルギー（Ｊ／ｍｏｌ）、Δｖ_iはそれぞれの原子団のモル体積（ｃｍ³／ｍｏｌ）である。）の式から算出する方法が挙げられる。
【００２８】
このような水溶性有機溶剤としては、例えば、メチルアルコール、エチルアルコール、ｎ−プロピルアルコール、イソプロピルアルコール、ｎ−ブチルアルコール、ｓｅｃ−ブチルアルコール、ｔｅｒｔ−ブチルアルコール等の低級アルコール類；エチレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、プロピレングリコール、ジプロピレングリコール、トリプロピレングリコール、１，２−ブタンジオール、１，３−ブタンジオール、１，４−ブタンジオ−ル、チオジグリコール、ネオペンチルグリコール、１，４−シクロヘキサンジオール、ポリエチレングリコール等のジオール類；エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノイソプロピルエーテル、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メチルエーテル、ジエチレングリコールモノエチルエーテル、トリエチレングリコーリモノメチルエーテル、トリエチレングリコールモノエチルエーテル、プロピレングリコールモノメチルエーテル、ジプロピレングリコールモノメチルエーテル等のアルキレングリコールモノアルキルエーテル類；グリセリン、１，２，４−ブタントリオール、１，２，６−ヘキサントリオール、１，２，５−ペンタントリオール、トリメチロールエタン、トリメチロールプロパン、ペンタエリスリトール等のポリオール類；テトラヒドロフラン、ジオキサン等の環状エーテル類；ジメチルスルホキシキド、ダイアセトンアルコール、グリセリンモノアリルエーテル、Ｎ−メチル−２−ピロリドン、２−ピロリドン、γ−ブチロラクトン、１，３−ジメチル−２−イミダゾリジノン、スルフォラン、β−ジヒドロキシエチルウレア、ウレア、アセトニルアセトン、ジメチルホルムアミド、ジメチルアセトアミド、アセトン、ジアセトンアルコール等が挙げられる。
【００２９】
これらの中でも、沸点が１２０℃以上の水溶性有機溶剤を使用すると、ノズル先端部でのインク濃縮が抑制されるため好ましい。これらの水溶性有機溶剤のインク中に占める割合としては、インク全質量に対して、好ましくは５〜５０質量％、より好ましくは１０〜３０質量％である。
【００３０】
以上が本発明のインクジェット記録用インクの構成材料であるが、これらの材料以外に、界面活性剤、ｐＨ調整剤、酸化防止剤、防黴剤等の各種の添加剤を添加してもよい。
【００３１】
本発明のインクジェット記録方法は、インクにエネルギーを与えてインクを飛翔させて行なうインクジェット記録方法に、上記インクを使用することである。エネルギーとしては、熱エネルギーや力学的エネルギーを用いることができるが、熱エネルギーを用いる方法が好ましい。
【００３２】
本発明のインクジェット記録方法においては、被記録媒体は限定されるものではないが、いわゆるインクジェット専用紙と呼ばれる、少なくとも一方の面にインクを受容するコーティング層を持つ被記録媒体等が好ましく使用される。コーティング層を持つ被記録媒体としては、少なくとも親水性ポリマー及び／又は無機多孔質体を含有した少なくとも一方の面にインクを受容するコーティング層を持つ被記録媒体が望ましい。次に、上記した本発明のインクジェット記録用インクを用いて記録を行なうのに好適な、本発明のインクジェット記録装置の一例を以下に説明する。
【００３３】
（熱エネルギーを利用したインクジェット記録装置）
まず、熱エネルギーを利用したインクジェット記録装置の主要部であるヘッド構成の一例を図１及び図２に示す。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線での切断面図である。ヘッド１３はインクを通す流路（ノズル）１４を有する、ガラス、セラミック、シリコン又はプラスチック板等と、発熱素子基板１５とを接着して得られる。発熱素子基板１５は、酸化シリコン、窒化シリコン、炭化シリコン等で形成される保護層１６、アルミニウム、金、アルミニウム−銅合金等で形成される電極１７−１及び１７−２、ＨｆＢ₂、ＴａＮ、ＴａＡｌ等の高融点材料から形成される発熱抵抗体層１８、熱酸化シリコン、酸化アルミニウム等で形成される蓄熱層１９、シリコン、アルミニウム、窒化アルミニウム等の放熱性のよい材料で形成される基板２０よりなっている。
【００３４】
上記ヘッド１３の電極１７−１及び１７−２にパルス状の電気信号が印加されると、発熱素子基板１５のｎで示される領域が急速に発熱し、この表面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がヘッドのノズル１４を通して吐出し、吐出オリフィス２２よりインク小滴２４となり、被記録材２５に向かって飛翔する。図３には、図１に示したヘッドを多数並べたマルチヘッドの一例の外観図を示す。このマルチヘッドは、マルチノズル２６を有するガラス板２７と、図１に説明したものと同じような発熱ヘッド２８を接着して作られている。
【００３５】
図４に、この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固定されており、カンチレバーの形態をなす。ブレード６１は記録ヘッド６５による記録領域に隣接した位置に配置され、又、本例の場合、記録ヘッド６５の移動経路中に突出した形態で保持される。
【００３６】
６２は記録ヘッド６５の突出口面のキャップであり、ブレード６１に隣接するホームポジションに配置され、記録ヘッド６５の移動方向と垂直な方向に移動して、インク吐出口面と当接し、キャッピングを行なう構成を備える。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６５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及びインク吸収体６３によって吐出回復部６４が構成され、ブレード６１及びインク吸収体６３によって、吐出口面に水分、塵挨等の除去が行なわれる。
【００３７】
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なう記録ヘッド、６６は記録ヘッド６５を搭載して記録ヘッド６５の移動を行なうためのキャリッジである。キャリッジ６６は、ガイド軸６７と摺動可能に係合し、キャリッジ６６の一部はモーター６８によって駆動されるべルト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。
【００３８】
５１は被記録材を挿入するための紙給部、５２は不図示のモーターにより駆動される紙送りローラーである。これらの構成により記録ヘッド６５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ー５３を配した排紙部へ排紙される。以上の構成において、記録ヘッド６５が記録終了してホームポジションへ戻る際、吐出回復部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。その結果、記録ヘッド６５の吐出口がワイピングされる。
【００３９】
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なう場合、キャップ６２は記録ヘッドの移動経路中に突出するように移動する。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揚合、キャップ６２及びブレード６１は上記したワイピングの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ため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なわれる。
【００４０】
図５は、記録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納したインク収容部、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にする。４４は廃インクを受容するインク吸収体である。インク収容部としてはインクとの接液面がポリオレフイン、特にポリエチレンで形成されているものが好ましい。
【００４１】
本発明で使用されるインクジェット記録装置としては、上述のように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に示すようなそれらが一体になったものにも好適に用いられる。図６において、７０は記録ユニットであり、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を用いることが本発明にとって好ましい。また、インク吸収体を用いず、インク収容部が内部にバネ等を仕込んだインク袋であるような構造でもよい。７２はカートリッジ内部を大気に連通させるための大気連通口である。この記録ユニット７０は図４に示す記録ヘッド６５に換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。
【００４２】
（力学的エネルギーを利用したインクジェット記録装置）
次に、力学的エネルギーを利用したインクジェット記録装置の好ましい一例としては、複数のノズルを有するノズル形成基板と、ノズルに対向して配置される圧電材料と導電材料からなる圧力発生素子と、この圧力発生素子の周囲を満たすインクを備え、印加電圧により圧力発生素子を変位させ、インクの小液滴をノズルから吐出させるオンデマンドインクジェット記録ヘッドを挙げることができる。その記録装置の主要部である記録ヘッドの構成の一例を図７に示す。
【００４３】
ヘッドは、インク室（不図示）に連通したインク流路８０と、所望の体積のインク滴を吐出するためのオリフィスプレート８１と、インクに直接圧力を作用させる振動板８２と、この振動板８２に接合され、電気信号により変位する圧電素子８３と、オリフィスプレート８１、振動板８２等を指示固定するための基板８４とから構成されている。
【００４４】
図７において、インク流路８０は、感光性樹脂等で形成され、オリフィスプレート８１は、ステンレス、ニッケル等の金属を電鋳やプレス加工による穴あけ等により吐出口８５が形成され、振動板８２は、ステンレス、ニッケル、チタン等の金属フィルム及び高弾性樹脂フィルム等で形成され、圧電素子８３は、チタン酸バリウム、ＰＺＴ等の誘電体材料で形成される。以上のような構成の記録ヘッドは、圧電素子８３にパルス状の電圧を与え、歪み応力を発生させ、そのエネルギーが圧電素子８３に接合された振動板を変形させ、インク流路８０内のインクを垂直に加圧しインク滴（不図示）をオリフィスプレート８１の吐出口８５より吐出して記録を行なうように動作する。このような記録ヘッドは、図４に示したものと同様なインクジェット記録装置に組み込んで使用される。インクジェット記録装置の細部の動作は、先述と同様に行なうもので差しつかえない。
【００４５】
【実施例】
以下、実施例に基づき本発明を詳細に説明する。本発明はこれらの実施例に限定されるものではない。尚、文中、「部」、及び「％」とあるのは質量基準である。
［参考例１］
（高分子分散剤Ａの作製）
疎水性ブロックと親水性ブロックからなるＡＢジブロック共重合体の合成：三方活栓を取り付けたガラス容器内を窒素置換した後、窒素ガス雰囲気下、２５０℃で加熱し吸着水を除去した。系を室温に戻した後、イソブチルビニルエーテル１２ミリモル、酢酸エチル１６ミリモル、１−イソブトキシエチルアセテート０．１ミリモル、及びトルエン１１ｃｍ³を加え、系内温度が０℃に達したところでエチルアルミニウムセスキクロライド０．２ミリモルを加え重合を開始し、ＡＢジブロックポリマーのＡブロックを合成した。
【００４６】
分子量を時分割に分子ふるいカラムクロマトグラフィー（ＧＰＣ）を用いてモニタリングし、Ａブロックの重合が完了した後、２−ヒドロキシエチルビニルエーテルの水酸基をトリメチルクロロシランでシリル化したビニルモノマー１２ミリモルを添加することで、Ｂブロックの合成を行った。重合反応の停止は、系内に０．３％のアンモニア／メタノール溶液を加えて行い、トリメチルクロロシランでシリル化した水酸基の加水分解は水を添加することで行った。反応を終えた混合溶液中にジクロロメタンを加え希釈し、０．６Ｎの塩酸溶液で３回、次いで蒸留水で３回洗浄し、エバポレーターで濃縮・乾固したものを真空乾燥させてＡＢジブロック共重合体（高分子分散剤Ａ）を得た。化合物の同定は、ＮＭＲ及びＧＰＣを用いて行った。（Ｍｎ＝３．７×１０⁴、Ｍｎ／Ｍｗ＝１．３）
【００４７】
（色材分散体Ｉの作製）
市販の水不溶性色材であるＣ．Ｉ．ソルベントブラック２１８を１．０部と、アセトン９９．０部を混合し、４０℃に加温して均一に溶解するようによく攪拌した。この混合溶液を、テトラヒドロフラン９９．０部に高分子分散剤Ａ１．０部を溶解した溶液中に添加し混合した後、水１０．０部を添加した。その後、ロータリーエバポレーターで、アセトンとテトラヒドロフランを除去し、色材分散体Ｉを得た。得られた色材分散体中のアセトンとテトラヒドロフランの濃度をガスクロマトグラフィーで分析したが、共に検出されず色材分散体中には残留していないと判断される結果であった。
（インク１の作製）
・上記色材分散体Ｉ ５０．０部
・ジエチレングリコール １０．０部
・チオジグリコール １０．０部
・イオン交換水 ３０．０部
以上の成分を混合し、充分攪拌して、目的のインク１を得た。得られたインク中の色材分散体の平均粒子径をレーザー光散乱法による機器ＥＬＳ−８００（大塚電子社製）で測定したところ、４６ｎｍであった。
【００４８】
［参考例２］
（色材分散体IIの作製）
参考例１で使用した色材を、市販の水不溶性色材であるＣ．Ｉ．ソルベントブラック３に変更した以外は、参考例１と同様にして色材分散体IIを得た。得られた色材分散体中のアセトンとテトラヒドロフランの濃度をガスクロマトグラフィーで分析したが、共に検出されず色材分散体中には残留していないと判断される結果であった。
（インク２の作製）
・上記色材分散体II ５０．０部
・エチレングリコール ９．０部
・グリセリン １１．０部
・イオン交換水 ３０．０部
以上の成分を混合し、充分攪拌して、目的のインク２を得た。得られたインク中の色材分散体の平均粒子径をレーザー光散乱法による機器ＥＬＳ−８００（大塚電子社製）で測定したところ、４５ｎｍであった。
【００４９】
［実施例１］
（高分子分散剤Ｂの作製）
疎水性ブロックと親水性ブロックからなるＡＢジブロック共重合体の合成：三方活栓を取り付けたガラス容器内を窒素置換した後、窒素ガス雰囲気下２５０℃で加熱し吸着水を除去した。系を室温に戻した後、２−デカノキシエチルビニルエーテル１２ミリモル、酢酸エチル１６ミリモル、１−イソブトキシエチルアセテート０．１ミリモル、及びトルエン１１ｃｍ³を加え、系内温度が０℃に達したところでエチルアルミニウムセスキクロライド０．２ミリモルを加え重合を開始し、ＡＢジブロックポリマーのＡブロックを合成した。
【００５０】
分子量を時分割に分子ふるいカラムクロマトグラフィー（ＧＰＣ）を用いてモニタリングし、Ａブロックの重合が完了した後、４−（２−ビニロキシエトキシ）ベンゾイックアシッド（Ｂブロック）のカルボン酸部をエチル基でエステル化したビニルモノマー１２ミリモルを添加することで、Ｂブロックの合成を行った。重合反応の停止は、系内に０．３％のアンモニア／メタノール溶液を加えて行い、エステル化させたカルボキシル基は、水酸化ナトリウム／メタノール溶液で加水分解させてカルボン酸型に変化させた。後は参考例１と同様にして、ＡＢジブロック共重合体（高分子分散剤Ｂ）を得た。化合物の同定は、ＮＭＲ及びＧＰＣを用いて行った。（Ｍｎ＝３．５×１０⁴、Ｍｎ／Ｍｗ＝１．２）
【００５１】
（色材分散体IIIの作製）
色材を市販の水不溶性色材であるＣ．Ｉ．ソルベントブラック２９に変更し、高分子分散剤を上記高分子分散剤Ｂに変更した以外は、参考例１と同様にして色材分散体IIIを得た。得られた色材分散体中のアセトンとテトラヒドロフランの濃度をガスクロマトグラフィーで分析したが、共に検出されず色材分散体中には残留していないと判断される結果であった。
（インク３の作製）
・上記色材分散体III ４０．０部
・トリプロピレングリコール １５．０部
・トリエチレングリコール ５．０部
・イオン交換水 ４０．０部
以上の成分を混合し、充分攪拌して、目的のインク３を得た。得られたインク中の色材分散体の平均粒子径をレーザー光散乱法による機器ＥＬＳ−８００（大塚電子社製）で測定したところ、４１ｎｍであった。
【００５２】
［実施例２］
（高分子分散剤Ｃの作製）
疎水性ブロックと２つの親水性ブロックからなるＡＢＣトリブロック共重合体の合成：三方活栓を取り付けたガラス容器内を窒素置換した後、窒素ガス雰囲気下２５０℃で加熱し吸着水を除去した。系を室温に戻した後、ｎ−オクタデシルビニルエーテル１２ミリモル、酢酸エチル１６ミリモル、１−イソブトキシエチルアセテート０．１ミリモル、及びトルエン１１ｃｍ³を加え、系内温度が０℃に達したところでエチルアルミニウムセスキクロライド０．２ミリモルを加え重合を開始し、ＡＢＣトリブロックポリマーのＡブロックを合成した。
【００５３】
分子量を時分割に分子ふるいカラムクロマトグラフィー（ＧＰＣ）を用いてモニタリングし、Ａブロックの重合が完了した後、２−（２−（２−（２−メトキシエトキシ）エトキシ）エトキシ）エトキシビニルエーテル（Ｂブロック）２４ミリモルを添加し重合を続行した。同様にＧＰＣで分子量をモニタリングし、Ｂブロックの重合が完了した後、６−（２−ビニロキシエトキシ）ヘキサノイックアシッド（Ｃブロック）のカルボン酸部をエチル基でエステル化したビニルモノマー１２ミリモルを添加することで合成を行った。重合反応の停止は、系内に０．３％のアンモニア／メタノール溶液を加えて行い、エステル化させたカルボキシル基は、水酸化ナトリウム／メタノール溶液で加水分解させてカルボン酸型に変化させた。後は参考例１と同様にして、ＡＢＣトリブロック共重合体（高分子分散剤Ｃ）を得た。化合物の同定は、ＮＭＲ及びＧＰＣを用いて行った。（Ｍｎ＝３．７×１０⁴、Ｍｎ／Ｍｗ＝１．２）
【００５４】
（色材分散体IVの作製）
色材を市販の水不溶性色材であるＣ．Ｉ．ソルベントブラック４５に変更し、高分子分散剤を上記高分子分散剤Ｃに変更した以外は、参考例１と同様にして色材分散体IVを得た。得られた色材分散体中のアセトンとテトラヒドロフランの濃度をガスクロマトグラフィーで分析したが、共に検出されず色材分散体中には残留していないと判断される結果であった。
（インク４の作製）
・上記色材分散体IV ５０．０部
・トリエチレングリコール ２０．０部
・イオン交換水 ３０．０部
以上の成分を混合し、充分攪拌して、目的のインク４を得た。得られたインク中の色材分散体の平均粒子径をレーザー光散乱法による機器ＥＬＳ−８００（大塚電子社製）で測定したところ、４３ｎｍであった。
【００５５】
［比較例１］
（色材分散体Ｖの作製）
参考例１で使用したＣ．Ｉ．ソルベントブラック２７を使用し、高分子分散剤としてスチレン−マレイン酸ランダム共重合体（数平均分子量１０，０００）を使用した以外は参考例１と同様にして色材分散体Ｖを得た。
・上記色材分散体Ｖ ５０．０部
・ジエチレングリコール １０．０部
・チオジグリコール １０．０部
・イオン交換水 ３０．０部
以上の成分を混合し、充分攪拌して、ブラックインクを得た。
【００５６】
［比較例２］
（色材分散体VIの作製）
参考例１で使用したＣ．Ｉ．ソルベントブラック２７を使用し、高分子分散剤としてｎ−ブチルメタクリレート−メタクリル酸ブロック共重合体（数平均分子量１０，０００）を使用した以外は参考例１と同様にして色材分散体VIを得た。（インク６の作製）
・上記色材分散体VI ５０．０部
・ジエチレングリコール １０．０部
・チオジグリコール １０．０部
・イオン交換水 ３０．０部
以上の成分を混合し、充分攪拌して、ブラックインクを得た。
【００５７】
［比較例３］
（色材分散体VIIの作製）
参考例２で使用したＣ．Ｉ．ソルベントブラック３を使用し、分散剤としてポリオキシエチレンヘキサデシルエーテル（ＨＬＢ１２．９）を使用した以外は参考例１と同様にして色材分散体VIIを得た。
（インク７の作製）
・上記色材分散体VII ５０．０部
・トリプロピレングリコール ２０．０部
・イオン交換水 ３０．０部
以上の成分を混合し、充分攪拌して、ブラックインクを得た。
【００５８】
［比較例４］
（色材分散体VIIIの作製）
市販の顔料であるＣ．Ｉ．ピグメントブラック７を１０．０部、スチレン−マレイン酸ランダム共重合体（数平均分子量１０，０００）５．０部とイオン交換水８５．０部を混合し、ウルトラホモジナイザーで均一に分散するように良く攪拌混合し、色材分散体VIIIを得た。
（インク８の作製）
・上記色材分散体VIII ５０．０部
・トリプロピレングリコール ２０．０部
・イオン交換水 ３０．０部
以上の成分を混合し、充分攪拌して、ブラックインクを得た。
【００５９】
［比較例５］
（インク９の作製）
・Ｃ．Ｉ．ダイレクトブラック１７ ５．０部
・トリプロピレングリコール ２０．０部
・イオン交換水 ７５．０部
以上の成分を混合し、充分攪拌して、ブラックインクを得た。
【００６０】
（評価）
実施例１〜２のインクと比較例１〜５のインクを、記録信号に応じた熱エネルギーをインクに付与することによりインクを吐出させるオンデマンド型マルチ記録ヘッドを有するインクジェット記録装置ＢＪＦ−６６０（キヤノン製）にそれぞれ搭載して、光沢紙ＳＰ１０１（キヤノン製）に印字を行い表１記載の評価を行った。その結果、表１に記載したように、何れの実施例のインクも比較例のインクに比べて吐出安定性が良好で画像品位と堅牢性が良好な結果が得られた。
【００６１】
【表１】

【００６２】
＊１：吐出特性
５℃で湿度が１０％の環境下において、１００％ベタ画像を印字し１分間休止した後、再度１００％ベタ画像を印字した画像を下記の評価基準で評価した。
◎：白スジが全く無く、正常に印字されていた。
○：印字の最初の部分に僅かに白スジがみられた。
△：画像全体に白スジがみられた。
×：画像がほとんど印字されていなかった。
【００６３】
＊２：画像特性
５℃で湿度が１０％の環境下において、２５ｍｍ間隔の方眼模様を印字し、印字した画像を下記の評価基準で評価した。
◎：顕微鏡で観察しても印字が全く乱れることなく、方眼模様は２５ｍｍ間隔で正常に印字されていた。
○：顕微鏡で観察すると一部に印字の乱れがみられるが、方眼模様は２５ｍｍ間隔に印字されていた。
△：肉眼でも一部に印字の乱れがみられ、方眼模様の一部が２５ｍｍ間隔からずれていた。
×：全体で印字の乱れが肉眼でみられ、方眼模様の全体が２５ｍｍ間隔からずれていた。
【００６４】
＊３：耐光性
印字物にキセノンランプを１００時間照射した後の画像の反射濃度を測定し、耐光性試験前と耐光性試験後の反射濃度の残存率を求め耐光性の尺度とした。評価基準は下記の通りとした。
○：画像濃度の残存率が９５％以上であった。
△：画像濃度の残存率が９０％以上９５％未満であった。
×：画像濃度の残存率が９０％未満であった。
【００６５】
＊４：耐水性
印字から１２時間以上放置後、印字物を５分間水道水中に静止し、水を乾燥させた後の画像の反射濃度を測定し、耐水性試験前と耐水性試験後の反射濃度の残存率を求め耐水性の尺度とした。評価基準は下記の通りとした。
○：画像濃度の残存率が９０％以上であった。
△：画像濃度の残存率が８０％以上９０％未満であった。
×：画像濃度の残存率が８０％未満であった。
【００６６】
【発明の効果】
以上説明したように、本発明によれば、高い堅牢性を有し品位に優れた画像をどのような場合でも長期にわたって安定して記録することのできるインクジェット記録用ブラックインクを提供することができ、更には堅牢性と品位に優れた画像を記録し得るインクジェット記録方法とインクジェット記録装置を提供することができる。
【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の一例を示す縦断面図である。
【図２】 インクジェット記録装置のヘッドの一例を示す横断面図である。
【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概略斜視図である。
【図５】 インクカートリッジの一例を示す縦断面図である。
【図６】 記録ユニットの一例を示す斜視図である。
【図７】 インクジェット記録ヘッドの別の構成例を示す概略断面図である。
【符号の説明】
１３：ヘッド
１４：インク溝
１５：発熱ヘッド
１６：保護膜
１７−１、１７−２：電極
１８：発熱抵抗体層
１９：蓄熱層
２０：基板
２１：インク
２２：吐出オリフィス（微細孔）
２３：メニスカス
２４：インク小滴
２５：被記録材
２６：マルチ溝
２７：ガラス板
２８：発熱ヘッド
４０：インク袋
４２：栓
４４：インク吸収体
４５：インクカートリッジ
５１：給紙部
５２：紙送りローラー
５３：排紙ローラー
６１：ブレード
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
６７：ガイド軸
６８：モーター
６９：ベルト
７０：記録ユニット
７１：ヘッド部
７２：大気連通口
８０：インク流路
８１：オリフィスプレート
８２：振動板
８３：圧電素子
８４：基板
８５：吐出口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a black ink for inkjet recording, an inkjet recording method, an ink cartridge, and an inkjet recording apparatus. More particularly, the present invention relates to a black ink of a color material dispersion suitable for inkjet recording with high ejection reliability and good image characteristics, an inkjet recording method, an ink cartridge, and an inkjet recording apparatus using the ink.
[0002]
[Prior art]
Conventionally, water-insoluble colorants such as pigments having excellent fastness such as water resistance and light resistance have been widely used as colorants for printing inks. However, in order to use the water-insoluble color material as the color material of the water-based ink, it is required to stably disperse the water-insoluble color material in the aqueous medium. Therefore, a water-based ink of a color material dispersion is used in which a dispersant such as a polymer compound or a surfactant is added and a water-insoluble color material is uniformly dispersed in an aqueous medium.
[0003]
In recent years, water-based inks of such color material dispersions have been used as inks for ink-jet recording from the viewpoint of image fastness also in ink-jet recording applications. In ink jet recording, attempts have been made to impart a coagulation function or a water insolubilization function to a color material dispersion in ink in order to improve the fixability and water resistance of ink on paper. However, by imparting such a function to the color material dispersion, the dispersion stability in the ink is lowered, and the color material dispersion aggregates during storage of the ink, resulting in uneven density and sedimentation. There is a problem that clogging due to ink drying occurs at the nozzle tip of the ink jet apparatus, and the ejection stability is likely to be lowered.
[0004]
In order to solve the above problems, Patent Document 1 proposes an ink containing a block copolymer composed of a hydrophobic segment and a hydrophilic segment and an oil-soluble dye, but the stability as a dispersion is However, the ink used in the ink jet recording apparatus still has low ejection stability and has not reached the practical level.
[0005]
[Patent Document 1]
JP 2002-97395 A [0006]
[Problems to be solved by the invention]
The object of the present invention has been made in view of the above problems, and is a black ink for ink jet recording capable of stably recording an image having high fastness and excellent quality in any case over a long period of time. Is to provide. It is another object of the present invention to provide an ink jet recording method, an ink cartridge and an ink jet recording apparatus capable of recording an image having excellent fastness and quality.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that the following problems can be solved. That is, the present invention relates to a black ink for ink-jet recording composed of a polymer dispersant, a water-insoluble colorant, a water-soluble organic solvent, and water. I. Solvent Black 3, C.I. I. Solvent Black 27, C.I. I. Solvent Black 29, C.I. I. At least one element selected from the group consisting of Solvent Black 45, the polymeric dispersant is a block copolymer composed of a hydrophobic block and a hydrophilic block, formed by polymerizing a vinyl ether as monomer Monodea is, the hydrophilic block is composed of anionic vinyl ether, further it has the water-insoluble colorant is encapsulated with the polymer dispersant, the dispersed by the polymer dispersant the average particle size of dispersion of the water-insoluble colorant, characterized in der Rukoto below 80 nm, a black ink for inkjet recording.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The present inventors have found that by using the black ink for ink jet recording, an image having high fastness and excellent quality can be stably recorded in any case.
[0009]
This is because the use of a block copolymer composed of a hydrophobic block and a hydrophilic block as the polymer dispersant allows the hydrophobic block portion of the polymer dispersant to adhere uniformly to the surface of the colorant. This makes it possible to uniformly coat the colorant with the polymer dispersant without exposing the colorant, that is, to encapsulate the colorant. At this time, since the hydrophobic block is a polyvinyl ether having a large number of ether structures obtained by polymerizing vinyl ethers as monomers, the hydrophobic block is statically placed between the ether portion of the hydrophobic block and the hydrophobic block portion of the adjacent polymer dispersant. It is considered that an electrical interaction occurs, that is, a physical binding action occurs between the hydrophobic blocks of the polymer dispersants.
[0010]
Thereby, the stability of the capsule is improved, and the capsule state is stably maintained even during the ejection of the ink jet recording in which the dispersibility is likely to be unstable, and the ejection stability is considered to be improved. Also, in the printed image after recording, since the color material is protected by the capsule of the stable polymer dispersant, a part of the color material may be exposed when part of the color material is originally exposed or during ejection. It is considered that the fastness of the coloring material is improved as compared with the case where the color is exposed. Furthermore, since the hydrophilic part of the polymer dispersant is blocked, the affinity with the ink medium is good, compared to those using a randomly polymerized polymer dispersant containing a hydrophobic group, It is considered that the dispersion stability of the color material dispersion is greatly improved. This makes it difficult for the color material dispersion to aggregate and settle in the ink, and it is considered that not only the ejection stability but also the stability during long-term storage of the ink is improved.
[0011]
Furthermore, the present inventors have found that when ink containing a coloring material dispersion is used in an ink jet recording apparatus, when water in the ink evaporates at the nozzle tip of the ink jet head and the ink is concentrated, the dispersion stability As a water-insoluble colorant, at least a C.I. I. Solvent Black 3, C.I. I. Solvent Black 27, C.I. I. Solvent Black 29, C.I. I. It has been found that by using one or more water-insoluble colorants selected from the group consisting of Solvent Black 45, the affinity between the hydrophobic block of the polymer dispersant and the colorant is improved. As a result, even during the printing process of an inkjet printer where a large amount of water in the ink evaporates, the dispersion stability of the colorant dispersion is less likely to deteriorate, and the nozzle is not clogged and stable for a long period of time. It was possible to discharge.
[0012]
Hereinafter, the constituent materials of the black ink for inkjet recording of the present invention will be described in detail.
(Water-insoluble colorant)
The water-insoluble colorant used in the black ink for ink jet recording of the present invention includes at least C.I. I. Solvent Black 3, C.I. I. Solvent Black 27, C.I. I. Solvent Black 29, C.I. I. It is 1 or more types chosen from the group which consists of Solvent Black 45, These water-insoluble coloring materials can also be used in combination of 2 or more types besides using individually.
[0013]
The content of these water-insoluble colorants in the ink is preferably 0.1 to 20% by mass, more preferably 1.0 to 10% by mass, based on the total mass of the ink. If the amount of the color material is less than 0.1% by mass, it may be difficult to obtain a sufficient image density. If the amount of the color material exceeds 20% by mass, the ejection stability may be deteriorated due to clogging or the like in the nozzle. is there.
[0014]
Further, when the average particle size of the color material dispersion that these water-insoluble color materials form with the polymer dispersant described later in the ink is preferably 80 nm or less, more preferably 50 nm or less, the ejection stability is improved. Further improvement is achieved and the color developability of the printed image is improved. Examples of the method for measuring the particle size of the color material dispersion include a laser light scattering method, an X-ray small angle scattering method, a sedimentation method, and a method of directly observing with an electron microscope.
[0015]
(Polymer dispersant)
The polymer dispersant used in the black ink for ink jet recording of the present invention is obtained by polymerizing vinyl ethers as monomers, and includes at least one kind of hydrophobic block and at least one kind of hydrophilic block, respectively. It may be a block copolymer having two or more types of hydrophilic blocks or two or more types of hydrophobic blocks, or a single block copolymer or a mixture of two or more types of block copolymers. Even things can be used. Examples of the polymerization form of the copolymer include a linear type and a graft type, and a linear type block copolymer is preferable.
[0016]
The hydrophilic block of the polymer dispersant is preferably composed of anionic vinyl ethers or nonionic vinyl ethers. Alternatively, if the diblock body has two blocks, a block composed of an anionic vinyl ether and a block composed of a nonionic vinyl ether, the color material dispersion in the ink medium It is preferable because the stability of the body is further improved.
[0017]
When the hydrophilic block of the polymer dispersant is a diblock as described above, it has a hydrophobic polyvinyl ether block, a non-ionic hydrophilic polyvinyl ether block, and an anionic hydrophilic property. A block copolymer composed of polyvinyl ether blocks in order is more desirable because the stability of the colorant dispersion in the ink medium is further improved.
[0018]
The block of hydrophobic vinyl ethers forming the polymer dispersant is preferably a block having a repeating unit structure represented by the following general formula (1).
^{_{- (CH 2 -CH (OR 1}} )) - (1)
In the above general formula (1), R ¹ represents an aliphatic hydrocarbon group such as an alkyl group, an alkenyl group, a cycloalkyl group or a cycloalkenyl group, a phenyl group, a pyridyl group, a benzyl group, a toluyl group, a xylyl group, An aromatic hydrocarbon group in which a carbon atom may be substituted with a nitrogen atom, such as an alkylphenyl group, a phenylalkylene group, a biphenyl group, and a phenylpyridyl group. Moreover, the hydrogen atom on the aromatic ring may be substituted with a hydrocarbon group. R ¹ preferably has 1 to 18 carbon atoms.
[0019]
R ¹ may be a group represented by — (CH (R ² ) —CH (R ³ ) —O) _p —R ⁴ or — (CH ₂ ) _m — (O) _n —R ⁴ . In this case, R ² and R ³ each independently represents a hydrogen atom or a methyl group, and R ⁴ represents an aliphatic hydrocarbon group such as an alkyl group, an alkenyl group, a cycloalkyl group or a cycloalkenyl group, a phenyl group, a pyridyl group. An aromatic hydrocarbon group in which the carbon atom may be substituted with a nitrogen atom (on the aromatic ring, such as benzyl group, toluyl group, xylyl group, alkylphenyl group, phenylalkylene group, biphenyl group, phenylpyridyl group) The hydrogen atom may be substituted with a hydrocarbon group.), —CO—CH═CH ₂ , —CO—C (CH ₃ ) ═CH ₂ , —CH ₂ —CH═CH ₂ , —CH ₂ represents _{-C (CH 3) = CH 2} , hydrogen atoms of these groups is in the range which is chemically feasible fluorine, chlorine, it may be substituted with a halogen atom such as bromine. The number of carbon atoms of R ⁴ is 1 to 18 is preferred. p is preferably 1 to 18, m is preferably 1 to 36, and n is preferably 0 or 1.
[0020]
In R ¹ and R ⁴ , examples of the alkyl group or alkenyl group include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, Examples thereof include dodecyl, tetradecyl, hexadecyl, octadecyl, oleyl and the like, and examples of the cycloalkyl group or cycloalkenyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl and the like.
[0021]
Next, as a block of vinyl ethers having hydrophilicity, a block having a repeating unit structure selected from the following general formula (2) is preferable.
^{_{- (CH 2 -CH (OR 5}} )) - (2)
In the above general formula (2), R ⁵ represents — (CH ₂ —CH ₂ —O) _k —R ⁶ , — (CH ₂ ) _m — (O) _n —R ⁶ , —R ⁷ —X, — (CH ₂ —CH ₂ —O) _k —R ⁷ —X, — (CH ₂ ) _m — (O) _n —X. In this case, R ⁶ is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, and —CO—CH═CH ₂ , —CO—C (CH ₃ ) ═CH ₂ , —CH. ₂ —CH═CH ₂ , —CH ₂ —C (CH ₃ ) ═CH ₂ , R ⁷ represents an aliphatic hydrocarbon group such as an alkylene group, an alkenylene group, a cycloalkylene group, or a cycloalkenylene group, a phenylene group, An aromatic hydrocarbon group in which a carbon atom may be substituted with a nitrogen atom, such as a pyridylene group, a benzylene group, a toluylene group, a xylylene group, an alkylphenylene group, a phenylenealkylene group, a biphenylene group, and a phenylpyridylene group ( The hydrogen atom on the aromatic ring may be substituted with a hydrocarbon group), and the hydrogen atom in these groups is a group such as fluorine, chlorine, bromine and the like as long as it is chemically possible. And Gen atom may be substituted. X represents an anionic group selected from a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group. The number of carbon atoms in R ⁷ is 1-18 are preferred. k is preferably 1 to 18, m is preferably 1 to 36, and n is preferably 0 or 1.
[0022]
Although the structure of the monomer (Ia-Io) and polymer (II-a-II-e) is illustrated below, the polyvinyl ether structure used for this invention is not limited to these.
[Chemical 1]

[0023]
[Chemical 2]

[0024]
Furthermore, it is preferable that the number of repeating units of polyvinyl ether (in the above (II-a) to (II-e), m, n, l) is independently 1 to 10,000. Moreover, it is more preferable that the sum total is (m + n + 1 in the above (II-a) to (II-e)), 10 to 20,000. The number average molecular weight is preferably 500 to 20,000,000, more preferably 1,000 to 5,000,000, and most preferably 2,000 to 2,000,000.
[0025]
The proportion of such a polymer dispersant in the ink is preferably 0.1 to 20% by mass and more preferably 0.5 to 10% by mass with respect to the total mass of the ink. In addition, the content ratio of the polymer dispersant and the water-insoluble colorant in the ink is preferably a polymer dispersant: water-insoluble colorant = 1: 100 to 2: 1 in terms of solid mass ratio. Discharge stability and storage stability are improved.
[0026]
(Water-soluble organic solvent)
The water-soluble organic solvent used in the black ink for ink jet recording of the present invention can be used without limitation as long as it is a water-soluble organic solvent, and can also be used as a mixed solvent of two or more water-soluble organic solvents. When used as such a mixed solvent, a solid water-soluble organic compound may be contained as long as it is liquid when mixed.
[0027]
Among them, the water-soluble organic solvent has a solubility parameter in the range of 0.0 to +10.0 (J / cm ³ ) ^1/2 with respect to the solubility parameter of the hydrophilic block portion of the polymer dispersant. It is preferable that the water-soluble organic solvent has an ink jet nozzle because clogging of the nozzles of the inkjet head is less likely to occur. This solubility parameter (δ (J / cm ³ ) ^1/2 ) is expressed as the square root of the cohesive energy density of the solvent, and δ = (ΔE / V) ^{1/2 where} ΔE is the molar evaporation of the solvent. Heat and V are solvent-specific values indicating the solubility of the solvent calculated from the formula of the molar volume of the solvent. For example, δ = 47.0 for water, δ = 25.7 for ethanol, and δ = 14.9 for hexane. Further, the solubility parameter (δ) of the polymer dispersant is an experimentally calculated value in which the solubility parameter of the solvent that gives the infinite solubility or maximum swelling degree of the polymer dispersant = the solubility parameter of the polymer, It is a value calculated from the molecular cohesive energy of the functional group of the polymer dispersant. A method for calculating the solubility parameter (δ) of the polymer dispersant and the solvent from the molecular aggregation energy of the functional group is as follows: δ = (ΔE / V) ^1/2 = (ΣΔe _i / ΣΔv _i ) ^1/2 (wherein , ΔE is the heat of molar evaporation, V is the respective molar volume, Δe _i is the evaporation energy (J / mol) of each atomic group, and Δv _i is the molar volume (cm ³ / mol) of each atomic group. )).
[0028]
Examples of such water-soluble organic solvents include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol; ethylene glycol, diethylene glycol , Triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, thiodiglycol, neopentyl glycol, Diols such as 1,4-cyclohexanediol and polyethylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol Alkylene glycol monoalkyl ethers such as isopropyl ether, ethylene glycol monoallyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether Polyols such as glycerin, 1,2,4-butanetriol, 1,2,6-hexanetriol, 1,2,5-pentanetriol, trimethylolethane, trimethylolpropane, pentaerythritol; tetrahydrofuran, dioxane, etc. Cyclic ethers: dimethyl sulfoxide, diacetone alcohol, glycerol monoallylamine , N-methyl-2-pyrrolidone, 2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, sulfolane, β-dihydroxyethylurea, urea, acetonylacetone, dimethylformamide, dimethylacetamide, Acetone, diacetone alcohol, etc. are mentioned.
[0029]
Among these, it is preferable to use a water-soluble organic solvent having a boiling point of 120 ° C. or higher because ink concentration at the nozzle tip is suppressed. The proportion of these water-soluble organic solvents in the ink is preferably 5 to 50% by mass and more preferably 10 to 30% by mass with respect to the total mass of the ink.
[0030]
The above is the constituent material of the ink for ink jet recording of the present invention. In addition to these materials, various additives such as a surfactant, a pH adjuster, an antioxidant and an antifungal agent may be added.
[0031]
The ink jet recording method of the present invention is to use the above-described ink in an ink jet recording method performed by applying energy to the ink and causing the ink to fly. As energy, thermal energy or mechanical energy can be used, but a method using thermal energy is preferable.
[0032]
In the ink jet recording method of the present invention, the recording medium is not limited, but a recording medium having a coating layer for receiving ink on at least one side, which is called a so-called exclusive ink jet paper, is preferably used. . The recording medium having a coating layer is preferably a recording medium having a coating layer that receives ink on at least one surface containing at least a hydrophilic polymer and / or an inorganic porous material. Next, an example of the ink jet recording apparatus of the present invention suitable for recording using the ink for ink jet recording of the present invention will be described below.
[0033]
(Inkjet recording device using thermal energy)
First, an example of a head configuration which is a main part of an ink jet recording apparatus using thermal energy is shown in FIGS. 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. The head 13 is obtained by adhering a heating element substrate 15 and a glass, ceramic, silicon, or plastic plate having a flow path (nozzle) 14 through which ink passes. Heating element substrate 15, a silicon oxide, silicon nitride, the protective layer 16 formed of silicon carbide or the like, aluminum, gold, aluminum - electrodes 17-1 and 17-2 are made of copper alloy or the like, HfB _2, TaN, A heating resistor layer 18 formed of a high melting point material such as TaAl, a heat storage layer 19 formed of thermal silicon oxide, aluminum oxide or the like, and a substrate 20 formed of a material with good heat dissipation such as silicon, aluminum, or aluminum nitride. It has become more.
[0034]
When a pulsed electric signal is applied to the electrodes 17-1 and 17-2 of the head 13, the region indicated by n of the heating element substrate 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact with the surface. The pressure causes the meniscus 23 to protrude, and the ink 21 is ejected through the nozzles 14 of the head to form ink droplets 24 from the ejection orifices 22 and fly toward the recording material 25. FIG. 3 shows an external view of an example of a multi-head in which a large number of heads shown in FIG. 1 are arranged. This multi-head is made by adhering a glass plate 27 having multi-nozzles 26 and a heating head 28 similar to that described in FIG.
[0035]
FIG. 4 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held and fixed by a blade holding member, and forms a cantilever. The blade 61 is disposed at a position adjacent to the recording area by the recording head 65, and in this example, is held in a form protruding in the moving path of the recording head 65.
[0036]
Reference numeral 62 denotes a cap on the projection port surface of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, contacts the ink ejection port surface, and performs capping. The structure to perform is provided. 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 65. The blade 61, the cap 62, and the ink absorber 63 constitute a discharge recovery portion 64, and the blade 61 and the ink absorber 63 remove moisture, dust, and the like from the discharge port surface.
[0037]
Reference numeral 65 denotes a recording head which has discharge energy generating means and performs recording by discharging ink onto a recording material facing the discharge port surface on which the discharge port is arranged. Reference numeral 66 denotes a recording head mounted with the recording head 65. It is a carriage for moving. 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. Accordingly, the carriage 66 can move along the guide shaft 67, and the recording area by the recording head 65 and its adjacent area can be moved.
[0038]
51 is a paper feeding unit for inserting a recording material, and 52 is 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 65, and is discharged to a paper discharge unit provided with a paper discharge roller 53 as recording progresses. In the above configuration, when the recording head 65 finishes recording and returns to the home position, the cap 62 of the ejection 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 of the recording head 65 is wiped.
[0039]
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 is moved from the home position to the recording start position, the cap 62 and the blade 61 are in the same position as the wiping position described above. 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 ejection recovery, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves the recording area for recording. Then, the wiping is performed with this movement.
[0040]
FIG. 5 is a diagram illustrating an example of an ink cartridge that contains ink supplied to the recording head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink container, for example, an ink bag, in which supply ink is stored, 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. An ink absorber 44 receives waste ink. The ink container preferably has a liquid contact surface made of polyolefin, particularly polyethylene.
[0041]
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. It is done. 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 from the head portion 71 having a plurality of orifices. It is configured to be ejected as ink droplets. It is preferable for the present invention to use polyurethane as the material of the ink absorber. Alternatively, a structure in which the ink container is an ink bag with a spring or the like inside without using an ink absorber may be used. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 4 and is detachable from the carriage 66.
[0042]
(Inkjet recording device using mechanical energy)
Next, as a preferable example of an ink jet recording apparatus using mechanical energy, a nozzle forming substrate having a plurality of nozzles, a pressure generating element made of a piezoelectric material and a conductive material disposed opposite to the nozzles, and the pressure An on-demand ink jet recording head that includes ink that fills the periphery of the generating element, displaces the pressure generating element by an applied voltage, and discharges a small droplet of ink from a nozzle can be exemplified. An example of the configuration of a recording head which is a main part of the recording apparatus is shown in FIG.
[0043]
The head includes an ink flow path 80 communicating with an ink chamber (not shown), an orifice plate 81 for ejecting ink droplets of a desired volume, a vibration plate 82 that directly applies pressure to ink, and the vibration plate 82. And a substrate 84 for indicating and fixing the orifice plate 81, the diaphragm 82 and the like.
[0044]
In FIG. 7, an ink flow path 80 is formed of a photosensitive resin or the like, an orifice plate 81 has a discharge port 85 formed by electroforming or punching a metal such as stainless steel or nickel, and the vibration plate 82 is The piezoelectric element 83 is formed of a dielectric material such as barium titanate or PZT. The recording head configured as described above applies a pulsed voltage to the piezoelectric element 83 to generate a distortion stress, and the energy deforms the vibration plate bonded to the piezoelectric element 83, so that the ink in the ink flow path 80 is obtained. The ink is vertically pressed and ink droplets (not shown) are discharged from the discharge port 85 of the orifice plate 81 to perform recording. Such a recording head is used by being incorporated in an ink jet recording apparatus similar to that shown in FIG. The detailed operation of the ink jet recording apparatus can be performed in the same manner as described above.
[0045]
【Example】
Hereinafter, the present invention will be described in detail based on examples. The present invention is not limited to these examples. In the text, “parts” and “%” are based on mass.
[ Reference Example 1]
(Preparation of polymer dispersant A)
Synthesis of AB diblock copolymer consisting of hydrophobic block and hydrophilic block: The inside of a glass container equipped with a three-way cock was replaced with nitrogen, and then heated at 250 ° C. in a nitrogen gas atmosphere to remove adsorbed water. After returning the system to room temperature, 12 mmol of isobutyl vinyl ether, 16 mmol of ethyl acetate, 0.1 mmol of 1-isobutoxyethyl acetate and 11 cm ³ of toluene were added, and when the internal temperature reached 0 ° C., ethylaluminum sesquichloride was added. Polymerization was started by adding 0.2 mmol, and an A block of an AB diblock polymer was synthesized.
[0046]
The molecular weight is monitored in a time-sharing manner using molecular sieve column chromatography (GPC), and after the polymerization of the A block is completed, 12 mmol of vinyl monomer in which the hydroxyl group of 2-hydroxyethyl vinyl ether is silylated with trimethylchlorosilane is added. The B block was synthesized. The polymerization reaction was stopped by adding a 0.3% ammonia / methanol solution to the system, and hydrolysis of the hydroxyl group silylated with trimethylchlorosilane was performed by adding water. Dichloromethane is added to the mixed solution after the reaction to dilute, washed with 0.6N hydrochloric acid solution three times, then with distilled water three times, and concentrated and dried with an evaporator. A polymer (polymer dispersing agent A) was obtained. The compound was identified using NMR and GPC. (Mn = 3.7 × 10 ⁴ , Mn / Mw = 1.3)
[0047]
(Preparation of colorant dispersion I)
C., which is a commercially available water-insoluble colorant. I. 1.0 part of Solvent Black 218 and 99.0 parts of acetone were mixed and heated to 40 ° C. and stirred well so as to dissolve uniformly. This mixed solution was added to and mixed with a solution obtained by dissolving 1.0 part of the polymer dispersant A in 99.0 parts of tetrahydrofuran, and then 10.0 parts of water was added. Thereafter, acetone and tetrahydrofuran were removed with a rotary evaporator to obtain a colorant dispersion I. The concentration of acetone and tetrahydrofuran in the obtained color material dispersion was analyzed by gas chromatography, but both were not detected and were judged not to remain in the color material dispersion.
(Preparation of ink 1)
-50.0 parts of the above-mentioned colorant dispersion I-10.0 parts of diethylene glycol-10.0 parts of thiodiglycol-10.0 parts of ion-exchanged water 30.0 parts or more are mixed and sufficiently stirred to obtain the target ink 1. Obtained. It was 46 nm when the average particle diameter of the color material dispersion in the obtained ink was measured with an apparatus ELS-800 (manufactured by Otsuka Electronics Co., Ltd.) by a laser light scattering method.
[0048]
[ Reference Example 2]
(Preparation of Colorant Dispersion II)
The color material used in Reference Example 1 is a commercially available water-insoluble color material C.I. I. A colorant dispersion II was obtained in the same manner as in Reference Example 1 except that Solvent Black 3 was used. The concentration of acetone and tetrahydrofuran in the obtained color material dispersion was analyzed by gas chromatography, but both were not detected and were judged not to remain in the color material dispersion.
(Preparation of ink 2)
・ Coloring Material Dispersion II 50.0 parts ・ Ethylene glycol 9.0 parts ・ Glycerin 11.0 parts ・ Ion-exchanged water 30.0 parts The above ingredients are mixed and sufficiently stirred to obtain the target ink 2. It was. It was 45 nm when the average particle diameter of the color material dispersion in the obtained ink was measured with an apparatus ELS-800 (manufactured by Otsuka Electronics Co., Ltd.) by a laser light scattering method.
[0049]
[Example 1 ]
(Preparation of polymer dispersant B)
Synthesis of AB diblock copolymer consisting of hydrophobic block and hydrophilic block: The inside of a glass container equipped with a three-way stopcock was purged with nitrogen, and then heated at 250 ° C. in a nitrogen gas atmosphere to remove adsorbed water. After returning the system to room temperature, 12 mmol of 2-decanoxyethyl vinyl ether, 16 mmol of ethyl acetate, 0.1 mmol of 1-isobutoxyethyl acetate, and 11 cm ³ of toluene were added, and the system temperature reached 0 ° C. By the way, 0.2 mmol of ethylaluminum sesquichloride was added to initiate polymerization, and an A block of AB diblock polymer was synthesized.
[0050]
The molecular weight was monitored in a time-sharing manner using molecular sieve column chromatography (GPC), and after the polymerization of the A block was completed, the carboxylic acid part of 4- (2-vinyloxyethoxy) benzoic acid (B block) was ethylated. The B block was synthesized by adding 12 mmol of vinyl monomer esterified with a group. The polymerization reaction was stopped by adding a 0.3% ammonia / methanol solution to the system, and the esterified carboxyl group was hydrolyzed with a sodium hydroxide / methanol solution to be converted into a carboxylic acid type. Thereafter, an AB diblock copolymer (polymer dispersing agent B) was obtained in the same manner as in Reference Example 1. The compound was identified using NMR and GPC. (Mn = 3.5 × 10 ⁴ , Mn / Mw = 1.2)
[0051]
(Preparation of colorant dispersion III)
The coloring material is a commercially available water-insoluble coloring material C.I. I. A colorant dispersion III was obtained in the same manner as in Reference Example 1 except that the solvent was changed to Solvent Black 29 and the polymer dispersant was changed to the polymer dispersant B. The concentration of acetone and tetrahydrofuran in the obtained color material dispersion was analyzed by gas chromatography, but both were not detected and were judged not to remain in the color material dispersion.
(Preparation of ink 3)
-Color material dispersion III 40.0 parts-Tripropylene glycol 15.0 parts-Triethylene glycol 5.0 parts-Ion-exchanged water 40.0 parts 3 was obtained. It was 41 nm when the average particle diameter of the coloring material dispersion in the obtained ink was measured with an apparatus ELS-800 (manufactured by Otsuka Electronics Co., Ltd.) by a laser light scattering method.
[0052]
[Example 2 ]
(Preparation of polymer dispersant C)
Synthesis of ABC Triblock Copolymer Containing Hydrophobic Block and Two Hydrophilic Blocks: The inside of a glass container equipped with a three-way cock was replaced with nitrogen, and then heated at 250 ° C. in a nitrogen gas atmosphere to remove adsorbed water. After returning the system to room temperature, 12 mmol of n-octadecyl vinyl ether, 16 mmol of ethyl acetate, 0.1 mmol of 1-isobutoxyethyl acetate, and 11 cm ³ of toluene were added, and when the internal temperature reached 0 ° C., ethyl aluminum Polymerization was started by adding 0.2 mmol of sesquichloride, and an A block of ABC triblock polymer was synthesized.
[0053]
The molecular weight was monitored in a time-sharing manner using molecular sieve column chromatography (GPC), and after the polymerization of the A block was completed, 2- (2- (2- (2-methoxyethoxy) ethoxy) ethoxy) ethoxyvinyl ether (B Block) 24 mmol was added and polymerization was continued. Similarly, the molecular weight was monitored by GPC, and after the polymerization of the B block was completed, 12 mmol of vinyl monomer obtained by esterifying the carboxylic acid part of 6- (2-vinyloxyethoxy) hexanoic acid (C block) with an ethyl group The synthesis was performed by adding The polymerization reaction was stopped by adding a 0.3% ammonia / methanol solution to the system, and the esterified carboxyl group was hydrolyzed with a sodium hydroxide / methanol solution to be converted into a carboxylic acid type. Thereafter, an ABC triblock copolymer (polymer dispersant C) was obtained in the same manner as in Reference Example 1. The compound was identified using NMR and GPC. (Mn = 3.7 × 10 ⁴ , Mn / Mw = 1.2)
[0054]
(Preparation of colorant dispersion IV)
The coloring material is a commercially available water-insoluble coloring material C.I. I. A colorant dispersion IV was obtained in the same manner as in Reference Example 1 except that the solvent was changed to Solvent Black 45 and the polymer dispersant was changed to the polymer dispersant C. The concentration of acetone and tetrahydrofuran in the obtained color material dispersion was analyzed by gas chromatography, but both were not detected and were judged not to remain in the color material dispersion.
(Preparation of ink 4)
-Color material dispersion IV 50.0 parts-Triethylene glycol 20.0 parts-Ion exchange water 30.0 parts The above ingredients were mixed and sufficiently stirred to obtain the desired ink 4. It was 43 nm when the average particle diameter of the color material dispersion in the obtained ink was measured with an apparatus ELS-800 (manufactured by Otsuka Electronics Co., Ltd.) by a laser light scattering method.
[0055]
[Comparative Example 1]
(Preparation of colorant dispersion V)
C. used in Reference Example 1 I. A colorant dispersion V was obtained in the same manner as in Reference Example 1 except that Solvent Black 27 was used and a styrene-maleic acid random copolymer (number average molecular weight 10,000) was used as the polymer dispersant.
-Color material dispersion V 50.0 parts-Diethylene glycol 10.0 parts-Thiodiglycol 10.0 parts-Ion-exchanged water 30.0 parts The above ingredients were mixed and sufficiently stirred to obtain a black ink. .
[0056]
[Comparative Example 2]
(Preparation of colorant dispersion VI)
C. used in Reference Example 1 I. A colorant dispersion VI was obtained in the same manner as in Reference Example 1 except that Solvent Black 27 was used and n-butyl methacrylate-methacrylic acid block copolymer (number average molecular weight 10,000) was used as the polymer dispersant. It was. (Preparation of ink 6)
-Color material dispersion VI 50.0 parts-Diethylene glycol 10.0 parts-Thiodiglycol 10.0 parts-Ion exchange water 30.0 parts The above ingredients were mixed and stirred well to obtain a black ink. .
[0057]
[Comparative Example 3]
(Preparation of colorant dispersion VII)
C. used in Reference Example 2 I. A colorant dispersion VII was obtained in the same manner as in Reference Example 1 except that Solvent Black 3 was used and polyoxyethylene hexadecyl ether (HLB12.9) was used as a dispersant.
(Preparation of ink 7)
-50.0 parts of the above color material dispersion VII-20.0 parts of tripropylene glycol-30.0 parts of ion-exchanged water The above components were mixed and sufficiently stirred to obtain a black ink.
[0058]
[Comparative Example 4]
(Preparation of colorant dispersion VIII)
C., a commercially available pigment. I. Pigment Black 7 is mixed with 10.0 parts, styrene-maleic acid random copolymer (number average molecular weight 10,000) 5.0 parts and ion-exchanged water 85.0 parts, and uniformly dispersed with an ultrahomogenizer. The mixture was well stirred and mixed to obtain a colorant dispersion VIII.
(Preparation of ink 8)
-50.0 parts of the above colorant dispersion VIII-20.0 parts of tripropylene glycol-30.0 parts or more of ion-exchanged water were mixed and sufficiently stirred to obtain a black ink.
[0059]
[Comparative Example 5]
(Preparation of ink 9)
・ C. I. Components of Direct Black 17 5.0 parts, Tripropylene glycol 20.0 parts, Ion-exchanged water 75.0 parts or more were mixed and sufficiently stirred to obtain a black ink.
[0060]
(Evaluation)
Inkjet recording apparatus BJF-660 having an on-demand type multi-recording head that ejects ink by applying thermal energy according to a recording signal to the ink of Examples 1 and 2 and Comparative Examples 1 to 5 (ink) Mounted on Canon), printed on glossy paper SP101 (made by Canon), and evaluated in Table 1. As a result, as shown in Table 1, the inks of all the examples had better ejection stability and better image quality and fastness than the comparative inks.
[0061]
[Table 1]

[0062]
* 1: In an environment where the discharge characteristics were 5 ° C. and the humidity was 10%, a 100% solid image was printed and paused for 1 minute.
A: There were no white stripes and printing was normal.
○: Slight white streaks were observed at the beginning of printing.
Δ: White streaks were observed throughout the image.
X: The image was hardly printed.
[0063]
* 2: A grid pattern with an interval of 25 mm was printed in an environment where the image characteristics were 5 ° C. and the humidity was 10%, and the printed image was evaluated according to the following evaluation criteria.
(Double-circle): Even if it observed with the microscope, the printing was not disturb | confused at all, and the grid pattern was printed normally by 25 mm space | interval.
○: Observed with a microscope, printing irregularities were partially observed, but square patterns were printed at intervals of 25 mm.
Δ: Printing disorder was partially observed even with the naked eye, and part of the grid pattern was shifted from the 25 mm interval.
X: Print disorder was observed with the naked eye as a whole, and the entire square pattern was shifted from the 25 mm interval.
[0064]
* 3: The reflection density of the image after irradiating the light-resistant printed matter with a xenon lamp for 100 hours was measured, and the residual ratio of the reflection density before and after the light resistance test was determined as a measure of light resistance. The evaluation criteria were as follows.
○: The residual ratio of the image density was 95% or more.
Δ: The residual ratio of the image density was 90% or more and less than 95%.
X: The residual ratio of the image density was less than 90%.
[0065]
* 4: After standing for 12 hours or more after water-resistant printing, the printed matter is left in tap water for 5 minutes, and the reflection density of the image after drying the water is measured, and the reflection before and after the water resistance test. The residual ratio of the concentration was determined and used as a measure of water resistance. The evaluation criteria were as follows.
A: The residual ratio of image density was 90% or more.
Δ: Residual rate of image density was 80% or more and less than 90%.
X: The residual ratio of the image density was less than 80%.
[0066]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a black ink for inkjet recording capable of stably recording an image having high fastness and excellent quality over a long period of time in any case. Furthermore, it is possible to provide an ink jet recording method and an ink jet recording apparatus capable of recording an image having excellent fastness and quality.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of a head of an ink jet recording apparatus.
FIG. 2 is a cross-sectional view illustrating an example of a head of an 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 schematic perspective view illustrating an example of an ink jet recording apparatus.
FIG. 5 is a longitudinal sectional view showing an example of an ink cartridge.
FIG. 6 is a perspective view illustrating an example of a recording unit.
FIG. 7 is a schematic cross-sectional view showing another configuration example of the ink jet recording head.
[Explanation of symbols]
13: head 14: ink groove 15: heating head 16: protective film 17-1, 17-2: electrode 18: heating resistor layer 19: heat storage layer 20: substrate 21: ink 22: ejection orifice (micropore)
23: Meniscus 24: Ink droplet 25: Recording material 26: Multi groove 27: Glass plate 28: Heat generating head 40: Ink bag 42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed unit 52: Paper feed Roller 53: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Discharge recovery unit 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head unit 72: Air Communication port 80: Ink channel 81: Orifice plate 82: Vibration plate 83: Piezoelectric element 84: Substrate 85: Ejection port

Claims (8)

In the black ink for ink-jet recording composed of a polymer dispersant, a water-insoluble colorant, a water-soluble organic solvent, and water, the water-insoluble colorant is at least C.I. I. Solvent Black 3, C.I. I. Solvent Black 27, C.I. I. Solvent Black 29, C.I. I. At least one element selected from the group consisting of Solvent Black 45, the polymeric dispersant is a block copolymer composed of a hydrophobic block and a hydrophilic block, formed by polymerizing a vinyl ether as monomer Monodea is, the hydrophilic block is composed of anionic vinyl ether, further it has the water-insoluble colorant is encapsulated with the polymer dispersant, the dispersed by the polymer dispersant the average particle size of dispersion of the water-insoluble colorant, characterized in der Rukoto below 80 nm, black ink for inkjet recording.   The hydrophilic block of the polymer dispersant has at least two types of blocks, a block composed of nonionic vinyl ethers and a block composed of anionic vinyl ethers. The black ink for inkjet recording as described in 2.   The polymer dispersant is composed of three blocks: a block composed of hydrophobic vinyl ethers, a block composed of nonionic hydrophilic vinyl ethers, and a block composed of anionic hydrophilic vinyl ethers. The black ink for inkjet recording according to claim 1, wherein the black ink is at least configured. Giving energy to the ink, in an ink jet recording method performed by ejecting the ink by applying an ink on a recording medium, the ink is in the ink-jet recording ink according to any one of claims 1 to 3 an ink jet recording method characterized in that there. The ink jet recording method according to claim 4 , wherein the energy is thermal energy. 5. The ink jet recording method according to claim 4 , wherein the recording material is a recording material having a coating layer for receiving ink on at least one surface. In the ink cartridge having an ink container portion containing an ink, an ink cartridge in which the ink, characterized in that it is a jet recording ink according to any one of claims 1 to 3. An ink cartridge having an ink container portion containing an ink, an ink jet recording apparatus having a head portion for ejecting the ink, the ink-jet recording according to any one of claims 1 to 3 An ink jet recording apparatus , characterized in that the ink is a printing ink.

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