JP3549128B2 - Recording liquid, ink jet recording method, recording liquid cartridge, recording unit, ink jet recording apparatus, and method for producing recording liquid - Google Patents

Description

【００２８】
本発明で使用する顔料は上記性能を満足するものならばどのようなものでも使用可能だが、黒インクに使用されるカーボンブラックとしては、ファーネス法、チャネル法で製造されたカーボンブラックで、１次粒子径が１５〜４０ｎｍ、ＢＥＴ法による比表面積が、５０〜３００ｍ^２ ／ｇ、ＤＢＰ給油量が、４０〜１５０ｍｌ／１００ｇ、揮発分が０．５〜１０％、ｐＨ値が２〜９であり、例えば、Ｎｏ．２３００，Ｎｏ．９００，ＭＣＦ８８，Ｎｏ．３３，Ｎｏ．４０，Ｎｏ．４５，Ｎｏ．５２，ＭＡ７，ＭＡ８，Ｎｏ．２２００Ｂ（以上三菱化成社製）、
【００２９】
ＲＡＶＥＮ１２５５（コロンビア社製）、
ＲＥＧＡＬ４００Ｒ，ＲＥＧＡＬ３３０Ｒ，ＲＥＧＡＬ６６０Ｒ，ＭＯＧＵＬＬ（キャボット社製）、
Ｃｏｌｏｒ Ｂｌａｃｋ ＦＷ１，Ｃｏｌｏｒ Ｂｌａｃｋ ＦＷ１８，Ｃｏｌｏｒ Ｂｌａｃｋ Ｓ１７０，Ｃｏｌｏｒ Ｂｌａｃｋ Ｓ１５０，Ｐｒｉｎｔｅｘ ３５，Ｐｒｉｎｔｅｘ Ｕ（デグッサ社製）等の市販品を使用することができる。
【００３０】
イエローインクに使用される顔料としては、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ２，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ３，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １３， Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １６，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ７４，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ８３、
【００３１】
マゼンタインクとして使用される顔料としては、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ７，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８（Ｃａ），Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８（Ｍｎ），Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５７（Ｃａ），Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １１２，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２、
【００３２】
シアンインクとして使用される顔料としては、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ １，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ ２，Ｃ．Ｉ．ＰｉｇｍｅｎｔＢｌｕｅ ３，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ １５：３，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ １６，Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ ２２，Ｃ．Ｉ．ＶａｔＢｌｕｅ ４，Ｃ．Ｉ．Ｖａｔ Ｂｌｕｅ ６等が挙げられるが、本発明のために新たに製造されたものでも使用可能である。また、これらの顔料のぬれ性の向上のために、その表面処理等を施してもよい。
【００３３】
本発明に使用できる分散剤としては、例えば高級脂肪酸塩、アルキル硫酸塩、アルキルエーテル硫酸塩、アルキルエステル硫酸塩、アルキルアリールエーテル硫酸塩、アルキルスルホン酸塩、スルホコハク酸塩、アルキルアリル及びアルキルナフタレンスルホン酸塩、アルキルリン酸塩、ポリオキシエチレンアルキルエーテルリン酸塩、アルキルアリールエーテルリン酸塩等のアニオン界面活性剤、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルアリルエーテル、ポリオキシエチレンポリオキシプロピレングリコール、グリセリンエステル、ソルビタンエステル、ショ糖エステル、グリセリンエステルのポリオキシエチレンエーテル、脂肪酸アルカノールアミド、ボリオキシエチレン脂肪酸アミド、アミンオキシド等のノニオン系界面活性剤、あるいは水溶性樹脂として、スチレン、スチレン誘導体、ビニルナフタレン誘導体、α，β−エチレン性不飽和カルボン酸の脂肪族アルコールエステル等、アクリル酸、アクリル酸誘導体、マレイン酸、マレイン酸誘導体、イタコン酸、イタコン酸誘導体、フマール酸、フマール酸誘導体等から選ばれた少なくとも２つ以上の単量体からなるブロック共重合体、あるいはランダム共重合体、または、これらの塩等が挙げられる。これらの樹脂は、塩基を溶解させた水溶液に可溶なアルカリ可溶型樹脂であり、インクジェット用インクに用いるものとして、分散液の低粘度化が可能で、分散も容易であるという利点があるため特に好ましく用いられる。
【００３４】
さらに、親水性単量体からなるホモポリマー、また、それらの塩でもよい。また、ポリビニルピロリドン、ポリビニルアルコール、カルボキシメチルセルロース、ナフタレンスルホン酸ホルムアルデヒド縮合物等の水溶性樹脂、ロジン、セラック等の天然樹脂も使用することが可能である。また、これらの水溶性樹脂の平均分子量は５００〜３００００の範囲が好ましく、さらに好ましくは、１０００〜１５０００の範囲である。
【００３５】
前記分散剤の水溶性界面活性剤および水溶性樹脂は記録液全重量に対して０．５〜１０重量％、好ましくは１〜５重量％の範囲で含有されることが好ましい。
【００３６】
本発明で使用するアルカリ可溶型樹脂は、塩基性物質を溶解させた水溶液に可溶な樹脂であれば特に限定されるものではないが、上記顔料の分散剤として使用できるアルカリ可溶樹脂で、平均分子量が２０，０００以下、好ましくは、１５，０００以下の樹脂を使用するのが、顔料の分散安定性の点からも好ましい。具体的には、スチレン、スチレン誘導体、ビニルナフタレン誘導体、α，β−エチレン性不飽和カルボン酸の脂肪族アルコールエステル等、アクリル酸、アクリル酸誘導体、マレイン酸、マレイン酸誘導体、イタコン酸、イタコン酸誘導体、フマール酸、フマール酸誘導体等から選ばれた少なくとも２つ以上の単量体からなるブロック共重合体、あるいはランダム共重合体等が挙げられる。
【００３７】
また、上記アルカリ可溶型樹脂を水に可溶化させる塩基性物質としては、モノエタノールアミン、ジエタノールアミン、トリエタノールアミン、エチルモノエタノールアミン、エチルジエタノールアミン、モノイソプロパノールアミン、ジイソプロパノールアミン、トリイソプロパノールアミン等のアルカノールアミンやアンモニア等の有機アミン、あるいは水酸化カリウム、水酸化ナトリウム等の無機塩基類を用いることができるが、インクジェット記録における吐出安定性の点から、アルカノールアミンを使用するのが特に好ましい。
【００３８】
本発明におけるインクにおいて好適な水性媒体は、水及び水溶性有機溶剤の混合溶媒であり、水としては種々のイオンを含有する一般の水ではなく、イオン交換水（脱イオン水）を使用するのが好ましい。なお、記録液中の水の含有量は、通常１０〜７０重量％、好ましくは２０〜５０重量％の範囲である。
【００３９】
また、その他、併用し得る任意の溶剤成分として、水と混合して使用される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炭素数１〜４のアルキルアルコール類：
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：
【００４０】
アセトン、ジアセトンアルコール等のケトンまたはケトンアルコール類：
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：
【００４１】
グリセリン、エチレングリコールモノメチル（またはエチル）エーテル、ジエチレングリコールメチル（またはエチル）エーテル、トリエチレングリコールモノメチル（またはエチル）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、２−ピロリドン、１，３−ジメチル−２−イミダゾリジノン等が挙げられる。
【００４２】
これらの多くの水溶性有機溶剤の中でも、ジエチレングリコール等の多価アルコール、トリエチレングリコールモノメチル（またはエチル）エーテル等の多価アルコールの低級アルキルエーテルが好ましい。
【００４３】
本発明の記録液のｐＨは、アルカリ可溶型樹脂の中和率が１００〜１２０％に規定されたものを使用するため、塩基性物質を添加して可溶化させた樹脂水溶液のｐＨより高くならないように他成分の添加等に注意しなければならない。ｐＨは８〜１０の範囲が好ましい。
【００４４】
また、本発明における記録液は、上記の成分の他に必要に応じて所望の物性値をもつ記録液とするために上記以外の界面活性剤、消泡剤、防腐剤等を添加することができる。さらにノズル乾燥防止剤として尿素、チオ尿素、エチレン尿素またはそれらの誘導体を含有することもできる。
【００４５】
一方、本発明に使用する分散機は、一般に使用される分散機なら如何なるものでもよいが、例えば、ボールミル、ロールミル、サンドミル等があげられるが、その中でも、高速度のサンドミルが好ましく、例えば、スーパーミル、サンドグラインダー、ビーズミル、アジテータミル、グレンミル、ダイノーミル、パールミル、コボルミル（いずれも商品名）等が挙げられる。
【００４６】
本発明において、所望の粒度分布を有する顔料の分散体を得る方法としては、分散機の粉砕メディアのサイズを小さくする、粉砕メディアの充填率を大きくする、また処理時間を長くする、吐出速度を遅くする、粉砕後フィルターや遠心分離機等で分級する等の手法が用いられる。または、それらの手法の組み合わせがあげられる。
【００４７】
次に、本発明の記録液を調製する方法は、まず、顔料を分散させた顔料分散液を調整し、これに水、水溶性有機溶剤及び水に可溶化させたアルカリ可溶性型樹脂等を所定の濃度になるように加えることにより行なう。
【００４８】
本発明の記録液としてインクを利用したインクジェット記録方法は、インク浸透性のない被記録物に対して、インク吐出口を複数備えた記録ヘッドからインクを付与して記録画像を形成するインクジェット記録方法であり、前記被記録物表面を清浄化処理する第１の工程と前記記録ヘッドの吐出口より画像記録信号に応じてインク滴を飛翔させ、前記被記録物の所定位置にインク滴を付与して記録画像を形成する第２の工程と、前記被記録物上に付与されたインクを硬化させる第３の工程とを有することを特徴とする。
【００４９】
更に本発明のインクジェット記録方法では、好ましくは、第２の工程はバブルジェット記録方式によって行われる。
本発明の記録液としてインクを用いて記録を行な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を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方法及び装置が挙げられる。
【００５０】
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）とを密着して得られる。発熱ヘッド１５は酸化シリコン等を形成させる保護膜１６、アルミニウム電極１７−１及び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良い基板２０より成っている。
【００５１】
インク２１は吐出オリフィス（微細孔）２２迄来ており、不図示の圧力によりメニスカス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。
【００５２】
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線での切断面である。
【００５３】
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１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る。
【００５４】
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具備する。更に６３はブレード６１に隣接して配設さ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。
【００５５】
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はこの記録ヘッド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と摺動可能に係合し、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に沿って移動が可能となり、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。
【００５６】
５１は被記録材を挿入する為の給紙部であり、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。
【００５７】
上記の構成において、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。
【００５８】
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、上記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。
【００５９】
上記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。
【００６０】
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納部、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フィン、特にポリエチレンで形成されているのが本発明にとって好ましい。
【００６１】
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となったものにも好適に用いられる。
【００６２】
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、ポリウレタンを用いることが本発明にとって好ましい。
【００６３】
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に対し着脱自在になっている。
【００６４】
【実施例】
以下に実施例および比較例を挙げて本発明を具体的に説明する。なお、以下に示す部は特に制限がない限り重量部を示す。
【００６５】
実施例１
（顔料分散液の作製）
スチレン−アクリル酸共重合体 ５．０部
（平均分子量 ７０００）
モノエタノールアミン １．０部
イオン交換水 ６８．０部
ジエチレングリコール ５．０部
【００６６】
上記成分を混合し、ウォーターバスで７０℃に加温し、樹脂分を完全に溶解させた。この溶液にカーボンブラック（ＭＣＦ８８ 三菱化成社製）を２０部、イソプロピルアルコール１．０部を加え、３０分間プレミキシングを行った後、下記の条件で分散処理を行なった。
【００６７】
分散機 ：サンドグラインダー
粉砕メディア ：ジルコニウムビーズ １ｍｍ径
粉砕メディアの充填率 ：５０％（体積）
粉砕時間 ：３時間
さらに遠心分離処理（１２０００ｒｐｍ、２０分間）を行い、粗大粒子を除去して分散液とした。
【００６８】
（インクの作製）
インクの作製は上記の分散液に以下の成分を加えることにより、所定の濃度になるように調製した。
上記分散液 １５部
グリセリン １０部
ジエチレングリコール １５部
３０％スチレン−アクリル酸共重合体水溶液 ５０部
（平均分子量７０００、モノエタノールアミン中和、中和率１１０％）
イオン交換水 １０部
インク中の顔料の平均粒径は０．１２μｍであった。
【００６９】
（注）重量平均分子量は、スチレンポリマーを標準としたＧＰＣ法により測定した値、平均粒径は動的光散乱法によって測定した値である。
【００７０】
実施例２
（顔料分散液の作製）
ポリオキシエチレンアルキルエーテルリン酸 ４．０部
モノエタノールアミン １．０部
イオン交換水 ６９．０部
ジエチレングリコール ５．０部
【００７１】
上記成分を混合し、ウォーターバスで７０℃に加温し、界面活性剤を完全に溶解させた。この溶液にＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２を２０部、イソプロピルアルコール１．０部を加え、３０分間プレミキシングを行った後、実施例１と同一条件で分散処理を行なった。
【００７２】
（インクの作製）
インクの作製は上記の分散液に以下の成分を加えることにより、所定の濃度になるように調製した。

インク中の顔料の平均粒径は０．１５μｍであった。
【００７３】
実施例３
（顔料分散液の作製）
ポリオキシエチレンアルキルエーテルリン酸 ４．０部
モノエタノールアミン １．０部
イオン交換水 ６９．０部
ジエチレングリコール ５．０部
【００７４】
上記成分を混合し、ウォーターバスで７０℃に加温し、界面活性剤を完全に溶解させた。この溶液にＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ １５：３を２０部、イソプロピルアルコール１．０部を加え、３０分間プレミキシングを行った後、実施例１と同一条件で分散処理を行なった。
【００７５】
（インクの作製）
インクの作製は上記の分散液に以下の成分を加えることにより、所定の濃度になるように調製した。

インク中の顔料の平均粒径は０．１０２μｍであった。
【００７６】
実施例４
（顔料分散液の作製）
スチレン−アクリル酸共重合体 ５．０部
（平均分子量 ７０００）
モノエタノールアミン １．０部
イオン交換水 ６８．０部
ジエチレングリコール ５．０部
【００７７】
上記成分を混合し、ウォーターバスで７０℃に加温し、樹脂分を完全に溶解させた。この溶液にＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ７４を２０部、イソプロピルアルコール１．０部を加え、３０分間プレミキシングを行った後、実施例１と同一条件で分散処理を行なった。
【００７８】
（インクの作製）
インクの作製は上記の分散液に以下の成分を加えることにより、所定の濃度になるように調製した。

インク中の顔料の平均粒径は０．１１μｍであった。
【００７９】
実施例５
（顔料分散液の作製）
スチレン−マレイン酸−メタクリル酸メチル共重合体 ５．０部
（平均分子量 ８２００）
モノエタノールアミン １．０部
イオン交換水 ６８．０部
エチレングリコール ５．０部
【００８０】
上記成分を混合し、ウォーターバスで７０℃に加温し、樹脂分を完全に溶解させた。この溶液にカーボンブラック（ＭＣＦ８８ 三菱化成社製）を２０部、イソプロピルアルコール１．０部を加え、３０分間プレミキシングを行った後、実施例１と同一条件で分散処理を行なった。
【００８１】
（インクの作製）
インクの作製は上記の分散液に以下の成分を加えることにより、所定の濃度になるように調製した。
上記分散液 ２５部
グリセリン １０部
ジエチレングリコール １５部
３４％スチレン−アクリル酸共重合体水溶液 ５０部
（平均分子量７０００、モノエタノールアミン中和、中和率１０２％）
インク中の顔料の平均粒径は０．１７μｍであった。
【００８２】
比較例１
実施例１のインク作製において、中和率が１４０％の３０％スチレン−アクリル酸共重合体水溶液を５０部として作製した。得られたインク中の顔料の平均粒径は０．１０２μｍであった。
【００８３】
比較例２
実施例２のインク作製において、２５％スチレン−メタクリル酸メチル共重合体水溶液の添加量を１０部として作製した。得られたインク中の顔料の平均粒径は０．１４μｍであった。
【００８４】
比較例３
実施例１のインク作製において、平均分子量が２５，０００のスチレン−アクリル酸共重合体を可溶化させた３０％水溶液を５０部として作製した。得られたインク中の顔料の平均粒径は０．１１μｍであった。
【００８５】
以上のようにして得られた実施例１〜５、比較例１〜３のインクを用いて熱エネルギーを付与してインクを吐出させるオンデマンドタイプのマルチヘッドを有する記録装置ＢＪ−２００（キヤノン社製）により下記の検討を行った結果を表１に示す。
【００８６】
（１）吐出安定性
○：１文字目からきれいに吐出し、連続印字中、不吐出、欠け、印字の乱れがほとんどない。
△：文字部分は比較的きれいに吐出するが、ベタ印字の部分で数箇所の不吐出が発生する。
×：文字部分においても、数文字印字させると不吐出が発生し、文字の判読が不可能な程度の印字の乱れを生じる。
【００８７】
（２）被記録媒体上での光透過性
印字したＯＨＰシートＣＦ−１０２（キヤノン社製）をＯＨＰにかけた時の発色性、及び光沢紙ＧＰ−１０１（キヤノン社製）、あるいは白いＰＥＴ（ポリエチレンテレフタレート）に１０％ポリビニルアルコール水溶液を塗布した光沢性フィルム上での発色性を評価した。
○：本来の色を発色し、Ｏ．Ｄも高い。
△：やや発色性に欠け、Ｏ．Ｄが低い。
×：カラー色が黒ずむ。
【００８８】
（３）擦過性
印字して得られた画像を１日放置後、手で擦ったり、消しゴムで消したりして評価した。
○：消しゴムで５回強く擦っても、文字やベタ画像がほとんど消えることはなく、また手も汚さない。
△：少し劣るレベル。
×：実質上、明らかに問題があるレベル。
【００８９】
（４）耐水性
ゼロックス４０２４紙に印字したサンプルを水道水に５分間浸し、処理前後の印字物の光学濃度の変化を残存率で表わした。
○：残存率が９８％以上
△：残存率が９０〜９７％
×：残存率が８９％以下
【００９０】
【表１】

【００９１】
【発明の効果】
本発明によれば、被記録媒体の種類によらず、特に、ＯＨＰシートや光沢性を有する特殊紙やフィルムに対しても、印字品位、発色性が良好で、かつ擦過性、耐水性にも優れた記録液、及び吐出の安定性にも優れたインクジェット記録を提供できる。
【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部の横断面図である。
【図２】インクジェット記録装置のヘッド部の縦断面図である。
【図３】図１及び図２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。
【符号の説明】
１ インクタンク
２ インクジェット記録ヘッド
３ インクジェット記録装置
１３ ヘッド
１４ 溝
１５ 発熱ヘッド
１６ 保護膜
１７−１，１７−２ アルミニウム電極
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
２３ メニスカス
２４ 記録小滴
２５ 被記録材
２６ マルチ溝
２７ ガラス板
２８ 発熱ヘッド
４０ インク収納部
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
５３ 排紙ローラ
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
７０ 記録ユニット
７１ オリフィス先端
７２ 大気連通口
７３ 基板[0001]
[Industrial applications]
The present invention relates to a recording liquid suitable for an ink-jet printer, an ink-jet recording method and a recording apparatus using the same, and particularly to an ink-jet recording in which recording is performed on a recording material by flying the recording liquid from the orifice of a recording head by the action of thermal energy. The present invention relates to a method and a recording device.
[0002]
[Prior art]
The ink jet recording method has an advantage that a low noise is generated at the time of recording and a high-resolution recorded image can be obtained at a high speed by using a highly integrated head. In such an ink jet recording system, an ink obtained by dissolving various water-soluble dyes in water or a mixture of water and an organic solvent is used. However, when water-soluble dyes are used, these water-soluble dyes are inherently inferior in light resistance, so that the light resistance of recorded images often becomes a problem.
[0003]
Further, since the ink is water-soluble, water resistance of a recorded image often becomes a problem. That is, when the recorded image comes in contact with rain, sweat, water for eating and drinking, etc., the recorded image may bleed or disappear.
[0004]
On the other hand, there is a similar problem in stationery using a dye in ink such as a ballpoint pen, and various water-based pigment inks for stationery have been proposed in order to solve the problems of light resistance and water resistance. Examples of studies on the dispersion stability, prevention of solidification of the ink at the pen tip, and prevention of abrasion of the ball of a ballpoint pen for practical use of aqueous pigment inks are disclosed in JP-A-58-80368 and JP-A-58-80368. Nos. 61-200182, JP-A-61-247774, JP-A-61-272278, JP-A-62-568, JP-A-62-101671, and JP-A-62-101672. And JP-A-1-249869 and JP-A-1-301760.
[0005]
Recently, ballpoint pens and markers using water-based pigment inks have come to market as commodities. Further, as an inkjet ink using an aqueous pigment ink, a pigment ink using a specific water-soluble solvent and a polymer dispersant has been proposed in JP-A-56-147859 and JP-A-56-147860. Have been. JP-A-4-57859, JP-A-4-57860 and the like propose inks using both pigments and dyes.
[0006]
By the way, various methods have been proposed for this ink jet recording method, some of which have been commercialized with improvements, and others of which are still being put to practical use.
[0007]
In this ink jet recording method, in order to satisfy the print quality, it is extremely important that the non-volatile components in the ejected ink rapidly aggregate on the recording medium. In this regard, in the case of pigment, as a dispersion having a particle size, it is larger than dye molecules and has a strong cohesive force. Therefore, even when a conventional aqueous pigment ink is used, evaporation and permeation of a liquid component on a recording medium are caused. Since the pigment is immediately agglomerated with respect to the composition change, good print quality can be obtained.
[0008]
However, as described above, the pigment has good cohesion, but the coagulation characteristics of the pigment cause the following problems. That is,
(1) If the printed portion on the recording medium is strongly rubbed or traced with a highlighter pen, the rubbing property such as contamination of the printed surface is reduced.
(2) Poor color developability such as blocking the light transmittance of OHP sheets or special glossy papers or films.
[0009]
[Problems to be solved by the invention]
The present invention solves the problems of the prior art that occurs when the above-described pigment ink is used. The purpose of the present invention is to improve the print quality and light emission regardless of the type of the recording medium. Another object of the present invention is to provide a recording liquid having improved abrasion properties, an ink jet recording method and a recording apparatus using the same.
Further, the present invention provides a recording liquid having excellent water resistance and light resistance inherent to the pigment ink.
[0010]
[Means for Solving the Problems]
That is, the present invention relates to a recording liquid containing at least a pigment, an alkali-soluble resin and water, wherein (a) the pigment has an average particle size of 0.05 to 0.3 μm and a content of 1 to 10% by weight. (B) the alkali-soluble resin has a neutralization ratio of 100 to 120%, a weight-average molecular weight of 20,000 or less, and the content is based on the pigment.3.4It is a recording liquid characterized in that it is used so as to be up to 5.2 times.
[0011]
Further, the present invention is formed by an inkjet method.Of the above recording liquidRecording by attaching droplets to the recording materialCharacterized by having a processThis is an inkjet recording method.
[0012]
In addition, the present inventionA recording liquid cartridge having a recording liquid storage section for storing the recording liquid.
[0013]
In addition, the present inventionAnd a recording liquid storage section for storing the recording liquid.Together with the head for dischargingCharacterized by havingIt is a recording unit.
[0014]
According to another aspect of the present invention, there is provided an ink jet recording apparatus including the above recording liquid and a recording head for discharging the recording liquid as droplets.
Further, the present invention relates to a method for producing a recording liquid containing 1 to 10% by weight of a pigment having an average particle diameter of 0.05 to 0.3 μm based on the total amount of the recording liquid, and (i) a pigment containing the pigment. Preparing a dispersion, and (ii) mixing a solution of an alkali-soluble resin having a weight average molecular weight of 20,000 or less with the pigment dispersion, wherein the solution of the alkali-soluble resin is The neutralization rate is 100 to 120%, and the alkali-soluble resin is3.4A method for producing a recording liquid, characterized in that the recording liquid is used so as to be contained up to 5.2 times.
[0015]
Hereinafter, the present invention will be described in detail.
The recording liquid of the present invention is a recording liquid containing at least a pigment, an alkali-soluble resin and water,
(1) The content of the pigment is 1 to 10% by weight.
(2) The average particle size of the pigment is 0.3 μm or less
(3) The content of the alkali-soluble resin is at least 3 times by weight based on the pigment.
(4) The neutralization rate of the alkali-soluble resin is 100 to 120%.
(5) The alkali-soluble resin has a weight average molecular weight (hereinafter abbreviated as average molecular weight) of 20,000 or less.
It is characterized by being.
[0016]
Further, the present invention relates to an ink jet recording method and a recording apparatus for performing recording by applying thermal energy to the recording liquid to discharge the recording liquid as droplets from fine holes.
[0017]
The first point of the present invention is that, in the ink jet recording, on the recording medium, how to control the aggregation of the pigment in the discharged recording liquid and fix the pigment, and, moreover, the ink jet recording suitability, that is, stable Discharge performance must also be ensured.
[0018]
Therefore, the present inventor has conducted intensive studies and found that the alkali-soluble resin is contained in an amount of 3 times or more, more preferably 5 times or more, by weight of the pigment, and the average particle size of the pigment is 0.3 μm or less. More preferably, when the thickness is 0.2 μm or less, the light transmittance to an OHP sheet, a special paper having a glossiness, or a film is improved. It has been found that abrasion can be obtained.
[0019]
This is because if the recording liquid contains a certain amount or more of an alkali-soluble resin with respect to the pigment, the aggregation of the pigment caused by evaporation and permeation of the liquid component in the ink on the recording medium causes a large amount of resin. At the same time, the pigment particle size is more effective when the particle size is equal to or less than a certain size, and at the same time, the pigment itself is also formed on the recording medium by the film effect of the alkali-soluble resin. This is considered to be due to the effect of being fixed at.
[0020]
The content of the pigment used in the present invention is 1 to 10% by weight, more preferably 2 to 7% by weight.It is.If the amount is less than 1% by weight, a sufficient image density cannot be obtained. If the amount exceeds 10% by weight, the amount of the alkali-soluble resin to be used increases, so that the viscosity of the entire ink considerably increases. , It becomes impossible to discharge the ink stably.
[0021]
The average particle size of the pigment used in the present invention is 0.3 μm or less, preferably 0.05 μm to 0.3 μm, and more preferably 0.05 μm to 0.2 μm.
[0022]
The average molecular weight of the alkali-soluble resin used in the present invention is desirably 20,000 or less. If it exceeds 20,000, the amount used in the viscosity range where ejection is possible is limited, so that sufficient effects can be obtained. Disappears. Further, it is preferably from 5,000 to 20,000, more preferably from 5,000 to 10,000, and within this range, there is an advantage that a particularly stable ejection property can be obtained.
[0023]
In addition, the content of the alkali-soluble resin is expressed as a weight% with respect to the pigment.3.4~ 5.2 times.
[0024]
Next, the second point of the present invention is that the water resistance of the recorded matter is not always satisfactory because the alkali-soluble resin used in the present invention is water-soluble. That is, a large amount of the pigment mixed with the water-soluble alkali-soluble resin on the recording medium is also flushed with water together with the resin. Alternatively, it takes a very long time to develop water resistance.
[0025]
Therefore, the present inventors have conducted intensive studies and found that the neutralization ratio when neutralizing the alkali-soluble resin used in the present invention with a basic substance to make it water-soluble is 100 to 120%, more preferably It has been found that by setting the content to 100 to 110%, good water resistance can be obtained in a short time after recording. That is, when the neutralization ratio exceeds 120%, a large amount of free basic substance is also present in the recording liquid when the aqueous solution of the alkali-soluble resin is used so as to have a predetermined resin concentration in the recording liquid. Will be. This is an obstacle to the alkali-soluble resin releasing the basic component and becoming water-insoluble on the recording medium, so that it becomes impossible to exhibit good water resistance in a short time after recording.
[0026]
The neutralization ratio referred to in the present invention is obtained by calculating the amount of a basic substance that dissolves an alkali-soluble resin from the acid value of the resin (mg amount of KOH that neutralizes the resin) according to the following equation (1). This is a numerical value in which the amount of the basic substance actually added is expressed in% with respect to the theoretical value.
[0027]
(Equation 1)

[0028]
Any pigment can be used as long as it satisfies the above performance. However, carbon black used in the black ink may be a carbon black manufactured by a furnace method or a channel method. Particle size is 15 to 40 nm, specific surface area by BET method is 50 to 300 m²  / G, DBP refueling amount is 40 to 150 ml / 100 g, volatile matter is 0.5 to 10%, and pH value is 2 to 9. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, No. 2200B (Mitsubishi Kasei)
[0029]
RAVE 1255 (Colombia),
REGAL400R, REGAL330R, REGAL660R, MOGULL (manufactured by Cabot),
Commercial products such as Color Black FW1, Color Black FW18, Color Black S170, Color Black S150, Printex 35, and Printex U (manufactured by Degussa) can be used.
[0030]
Examples of the pigment used for the yellow ink include C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 2, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 16, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 83,
[0031]
Pigments used as magenta inks include C.I. I. Pigment Red 5, C.I. I. Pigment Red 7, C.I. I. Pigment Red 12, C.I. I. Pigment Red 48 (Ca), C.I. I. Pigment Red 48 (Mn), C.I. I. Pigment Red 57 (Ca), C.I. I. Pigment Red 112, C.I. I. Pigment Red 122,
[0032]
Examples of the pigment used as the cyan ink include C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. Pigment Blue 3, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment 16, C.I. I. Pigment Blue 22, C.I. I. VatBlue 4, C.I. I. Vat Blue 6, etc., but those newly manufactured for the present invention can also be used. In order to improve the wettability of these pigments, a surface treatment or the like may be applied.
[0033]
Examples of dispersants usable in the present invention include higher fatty acid salts, alkyl sulfates, alkyl ether sulfates, alkyl ester sulfates, alkyl aryl ether sulfates, alkyl sulfonates, sulfosuccinates, alkyl allyls and alkyl naphthalene sulfones. Anionic surfactants such as acid salts, alkyl phosphates, polyoxyethylene alkyl ether phosphates, alkyl aryl ether phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene glycols Glycerin ester, sorbitan ester, sucrose ester, glycerin ester polyoxyethylene ether, fatty acid alkanolamide, polyoxyethylene fatty acid amide, amine oxide, etc. As a nonionic surfactant or a water-soluble resin, styrene, styrene derivatives, vinylnaphthalene derivatives, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, acrylic acid, acrylic acid derivatives, maleic acid, maleic acid Derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, block copolymers of at least two or more monomers selected from fumaric acid derivatives, or random copolymers, or salts thereof. . These resins are alkali-soluble resins that are soluble in an aqueous solution in which a base is dissolved, and have an advantage that the viscosity of the dispersion can be reduced and the dispersion is easy as those used for inkjet ink. Therefore, it is particularly preferably used.
[0034]
Further, a homopolymer composed of a hydrophilic monomer or a salt thereof may be used. It is also possible to use water-soluble resins such as polyvinylpyrrolidone, polyvinyl alcohol, carboxymethylcellulose, and naphthalenesulfonic acid formaldehyde condensate, and natural resins such as rosin and shellac. The average molecular weight of these water-soluble resins is preferably in the range of 500 to 30,000, and more preferably in the range of 1,000 to 15,000.
[0035]
It is preferable that the water-soluble surfactant and the water-soluble resin of the dispersant are contained in the range of 0.5 to 10% by weight, preferably 1 to 5% by weight based on the total weight of the recording liquid.
[0036]
The alkali-soluble resin used in the present invention is not particularly limited as long as it is a resin soluble in an aqueous solution in which a basic substance is dissolved, and is an alkali-soluble resin that can be used as a dispersant for the pigment. It is preferable to use a resin having an average molecular weight of 20,000 or less, preferably 15,000 or less, from the viewpoint of dispersion stability of the pigment. Specifically, styrene, styrene derivatives, vinylnaphthalene derivatives, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, etc., acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid A block copolymer comprising at least two or more monomers selected from derivatives, fumaric acid, fumaric acid derivatives, and the like, and a random copolymer are exemplified.
[0037]
Examples of the basic substance for solubilizing the alkali-soluble resin in water include monoethanolamine, diethanolamine, triethanolamine, ethyl monoethanolamine, ethyl diethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine. Although organic amines such as alkanolamine and ammonia, or inorganic bases such as potassium hydroxide and sodium hydroxide can be used, it is particularly preferable to use alkanolamine from the viewpoint of ejection stability in ink jet recording.
[0038]
An aqueous medium suitable for the ink of the present invention is a mixed solvent of water and a water-soluble organic solvent. As the water, not deionized water but general water containing various ions is used. Is preferred. The content of water in the recording liquid is usually in the range of 10 to 70% by weight, preferably 20 to 50% by weight.
[0039]
In addition, as other solvent components that can be used in combination, as a water-soluble organic solvent used by mixing with water, for example,
Alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol and tert-butyl alcohol:
Amides such as dimethylformamide and dimethylacetamide:
[0040]
Ketones or ketone alcohols such as acetone and diacetone alcohol:
Ethers such as tetrahydrofuran and dioxane: polyalkylene glycols such as polyethylene glycol and polypropylene glycol: ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, Alkylene glycols in which the alkylene group such as diethylene glycol contains 2 to 6 carbon atoms:
[0041]
Lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether:
N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.
[0042]
Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether are preferable.
[0043]
The pH of the recording liquid of the present invention is higher than the pH of the aqueous resin solution in which a basic substance is added and solubilized by using a resin whose neutralization ratio of the alkali-soluble resin is specified to be 100 to 120%. Care must be taken in the addition of other components to prevent this from happening. The pH is preferably in the range of 8-10.
[0044]
Further, in the recording liquid of the present invention, in addition to the above-described components, a surfactant, an antifoaming agent, a preservative, and the like other than the above may be added as necessary in order to obtain a recording liquid having desired physical properties. it can. Further, urea, thiourea, ethylene urea or derivatives thereof can be contained as a nozzle drying inhibitor.
[0045]
On the other hand, the dispersing machine used in the present invention may be any commonly used dispersing machine, such as a ball mill, a roll mill, and a sand mill. Among them, a high-speed sand mill is preferable, and Mills, sand grinders, bead mills, agitator mills, Glen mills, Dyno mills, pearl mills, Kobol mills (all trade names) and the like.
[0046]
In the present invention, as a method of obtaining a pigment dispersion having a desired particle size distribution, the size of the grinding media of the disperser is reduced, the filling rate of the grinding media is increased, the processing time is increased, and the discharge speed is increased. Techniques such as slowing down and classifying with a filter or a centrifuge after pulverization are used. Alternatively, a combination of these techniques can be used.
[0047]
Next, in the method for preparing the recording liquid of the present invention, first, a pigment dispersion liquid in which a pigment is dispersed is prepared, and water, a water-soluble organic solvent, an alkali-soluble resin solubilized in water, and the like are added thereto. By adding so as to obtain a concentration of
[0048]
An ink jet recording method using ink as a recording liquid according to the present invention is an ink jet recording method for forming a recorded image by applying ink from a recording head having a plurality of ink ejection ports to a recording material having no ink permeability. A first step of cleaning the surface of the recording object and causing the ink droplet to fly from an ejection port of the recording head in accordance with an image recording signal, and applying the ink droplet to a predetermined position of the recording object. And a third step of curing the ink applied on the recording medium.
[0049]
Further, in the ink jet recording method of the present invention, preferably, the second step is performed by a bubble jet recording method.
As a method and apparatus suitable for performing recording using ink as the recording liquid of the present invention, there is provided a method in which thermal energy corresponding to a recording signal is applied to ink in a chamber of a recording head and a droplet is generated by the thermal energy. And a device.
[0050]
FIGS. 1, 2 and 3 show examples of the configuration of a head which is a main part of the apparatus.
The head 13 is in close contact with a glass, ceramic or plastic plate having a groove 14 through which ink passes, and a heating head 15 (a head is shown in the figure, but is not limited to this) used for thermal recording. Is obtained. The heating head 15 is formed of a protective film 16 for forming silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 formed of nichrome or the like, a heat storage layer 19, and a substrate 20 having good heat dissipation such as alumina. Made up of
[0051]
The ink 21 reaches a discharge orifice (fine hole) 22 and forms a meniscus 23 by a pressure (not shown).
Now, when an electric signal is applied to the electrodes 17-1 and 17-2, the area of the heating head 15 indicated by n rapidly generates heat, bubbles are generated in the ink 21 in contact with the area, and the meniscus 23 Protrudes, the ink 21 is ejected, becomes a recording droplet 24 from the orifice 22, and flies toward the recording material 25.
[0052]
FIG. 3 shows an external view of a multi-head in which many heads shown in FIG. 1 are arranged. The multi-head is manufactured by closely adhering a glass plate 27 having a multi-groove 26 and a heating head 28 similar to that described with reference to FIG.
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.
[0053]
FIG. 4 shows an example of an ink jet recording apparatus incorporating such a head. In FIG. 4, reference numeral 61 denotes a blade serving as a wiping member, one end of which is held by a blade holding member and serves as a fixed end, forming a cantilever. The blade 61 is provided at a position adjacent to a recording area of the recording head.
[0054]
In the case of this example, the recording head is held in a form protruding into the movement path of the recording head. Reference numeral 62 denotes a cap, which is provided at a home position adjacent to the blade 61 and has a configuration in which the cap moves in a direction perpendicular to the direction of movement of the recording head to abut on the ejection port surface to perform capping. Reference numeral 63 denotes an ink absorber disposed adjacent to the blade 61, and is held in a form protruding into the movement path of the recording head, similarly to the blade 61. The blade 61, the cap 62, and the absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the absorber 63 remove moisture, dust, and the like from the ink ejection port surface.
[0055]
Reference numeral 65 denotes a recording head which has ejection energy generating means and performs recording by ejecting ink onto a recording material facing an ejection port surface provided with ejection ports, and 66 designates a recording head on which the recording head 65 is mounted. A carriage for performing the movement 65. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and the adjacent area.
[0056]
Reference numeral 51 denotes a paper feed unit for inserting a recording material, and reference numeral 52 denotes a paper feed roller driven by a motor (not shown). With such a configuration, the recording material is fed to a position facing the discharge port surface of the recording head, and is discharged to a discharge section provided with a discharge roller 53 as recording proceeds.
[0057]
In the above configuration, when the recording head 65 returns to the home position at 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 capping is performed with the cap 62 in contact with the ejection surface of the recording head 65, the cap 62 moves so as to protrude into the movement path of the recording head.
[0058]
When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as the position at the time of wiping described above. As a result, even in this movement, the ejection port surface of the recording head 65 is wiped.
[0059]
The above-described movement of the print head to the home position is performed not only at the end of printing or at the time of ejection recovery, but also at a predetermined interval while the print head moves through the printing area for printing to the home position adjacent to the printing area. Then, the wiping is performed along with this movement.
[0060]
FIG. 5 is a diagram illustrating an example of an ink cartridge that contains ink supplied to a head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink storage unit that stores the supply ink, for example, an ink bag, and a rubber stopper 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 the waste ink. In the present invention, it is preferable that the surface of the ink container that comes into contact with the ink is formed of polyolefin, particularly polyethylene.
[0061]
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 may be suitably used in the one in which they are integrated as shown in FIG.
[0062]
In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage unit storing ink, for example, an ink absorber is stored, and a head unit having a plurality of orifices in which the ink in the ink absorber is stored. It is configured to be ejected from 71 as ink droplets. As the material of the ink absorber, it is preferable for the present invention to use polyurethane.
[0063]
Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. This recording unit 70 is used in place of the recording head shown in FIG. 4, and is detachable from the carriage 66.
[0064]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The parts shown below are parts by weight unless otherwise specified.
[0065]
Example 1
(Preparation of pigment dispersion)
Styrene-acrylic acid copolymer 5.0 parts
(Average molecular weight 7000)
Monoethanolamine 1.0 part
68.0 parts of ion exchange water
Diethylene glycol 5.0 parts
[0066]
The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. To this solution, 20 parts of carbon black (MCF88 manufactured by Mitsubishi Kasei Co., Ltd.) and 1.0 part of isopropyl alcohol were added, and after premixing for 30 minutes, a dispersion treatment was performed under the following conditions.
[0067]
Dispersing machine: Sand grinder
Grinding media: Zirconium beads 1mm diameter
Filling rate of grinding media: 50% (volume)
Grinding time: 3 hours
Further, a centrifugal separation treatment (12000 rpm, 20 minutes) was performed to remove coarse particles to obtain a dispersion.
[0068]
(Preparation of ink)
The ink was prepared so as to have a predetermined concentration by adding the following components to the above dispersion.
15 parts of the above dispersion
Glycerin 10 parts
15 parts of diethylene glycol
50% 30% styrene-acrylic acid copolymer aqueous solution
(Average molecular weight 7000, monoethanolamine neutralization, neutralization rate 110%)
10 parts of ion exchange water
The average particle size of the pigment in the ink was 0.12 μm.
[0069]
(Note) The weight average molecular weight is a value measured by a GPC method using a styrene polymer as a standard, and the average particle diameter is a value measured by a dynamic light scattering method.
[0070]
Example 2
(Preparation of pigment dispersion)
4.0 parts of polyoxyethylene alkyl ether phosphoric acid
Monoethanolamine 1.0 part
69.0 parts of ion exchange water
Diethylene glycol 5.0 parts
[0071]
The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the surfactant. To this solution was added C.I. I. Pigment Red 122 and 1.0 part of isopropyl alcohol were added, and the mixture was premixed for 30 minutes, and then subjected to a dispersion treatment under the same conditions as in Example 1.
[0072]
(Preparation of ink)
The ink was prepared so as to have a predetermined concentration by adding the following components to the above dispersion.

The average particle size of the pigment in the ink was 0.15 μm.
[0073]
Example 3
(Preparation of pigment dispersion)
4.0 parts of polyoxyethylene alkyl ether phosphoric acid
Monoethanolamine 1.0 part
69.0 parts of ion exchange water
Diethylene glycol 5.0 parts
[0074]
The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the surfactant. To this solution was added C.I. I. Pigment Blue 15: 3 (20 parts) and isopropyl alcohol (1.0 part) were added, and the mixture was premixed for 30 minutes, and then subjected to a dispersion treatment under the same conditions as in Example 1.
[0075]
(Preparation of ink)
The ink was prepared so as to have a predetermined concentration by adding the following components to the above dispersion.

The average particle size of the pigment in the ink was 0.102 μm.
[0076]
Example 4
(Preparation of pigment dispersion)
Styrene-acrylic acid copolymer 5.0 parts
(Average molecular weight 7000)
Monoethanolamine 1.0 part
68.0 parts of ion exchange water
Diethylene glycol 5.0 parts
[0077]
The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. To this solution was added C.I. I. Pigment Yellow 74 and 20 parts of isopropyl alcohol were added, and the mixture was premixed for 30 minutes.
[0078]
(Preparation of ink)
The ink was prepared so as to have a predetermined concentration by adding the following components to the above dispersion.

The average particle size of the pigment in the ink was 0.11 μm.
[0079]
Example 5
(Preparation of pigment dispersion)
Styrene-maleic acid-methyl methacrylate copolymer 5.0 parts
(Average molecular weight 8200)
Monoethanolamine 1.0 part
68.0 parts of ion exchange water
Ethylene glycol 5.0 parts
[0080]
The above components were mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. To this solution, 20 parts of carbon black (MCF88 manufactured by Mitsubishi Kasei Co., Ltd.) and 1.0 part of isopropyl alcohol were added. After premixing for 30 minutes, dispersion treatment was performed under the same conditions as in Example 1.
[0081]
(Preparation of ink)
The ink was prepared so as to have a predetermined concentration by adding the following components to the above dispersion.
25 parts of the above dispersion
Glycerin 10 parts
15 parts of diethylene glycol
50 parts of 34% styrene-acrylic acid copolymer aqueous solution
(Average molecular weight 7000, monoethanolamine neutralization, neutralization rate 102%)
The average particle size of the pigment in the ink was 0.17 μm.
[0082]
Comparative Example 1
In the preparation of the ink of Example 1, 50 parts of a 30% styrene-acrylic acid copolymer aqueous solution having a neutralization ratio of 140% was prepared. The average particle size of the pigment in the obtained ink was 0.102 μm.
[0083]
Comparative Example 2
In the preparation of the ink of Example 2, the addition amount of the aqueous solution of 25% styrene-methyl methacrylate copolymer was 10 parts. The average particle size of the pigment in the obtained ink was 0.14 μm.
[0084]
Comparative Example 3
In preparing the ink of Example 1, 50 parts of a 30% aqueous solution in which a styrene-acrylic acid copolymer having an average molecular weight of 25,000 was solubilized was prepared. The average particle size of the pigment in the obtained ink was 0.11 μm.
[0085]
A recording apparatus BJ-200 (Canon Inc.) having an on-demand type multi-head for applying thermal energy and discharging ink by using the inks of Examples 1 to 5 and Comparative Examples 1 to 3 obtained as described above. Table 1 shows the results of the following investigations.
[0086]
(1) Discharge stability
○: Discharges finely from the first character, and almost no non-discharge, chipping, and printing disturbance during continuous printing.
Δ: The character portion is ejected relatively cleanly, but several non-ejections occur in the solid printing portion.
×: Even in the character portion, non-ejection occurs when several characters are printed, and the printing is disturbed to the extent that characters cannot be read.
[0087]
(2) Light transmittance on the recording medium
Coloring properties of OHP sheet CF-102 (Canon) printed on OHP, and gloss of 10% polyvinyl alcohol aqueous solution applied to glossy paper GP-101 (Canon) or white PET (polyethylene terephthalate) The color development on the functional film was evaluated.
：: Original color was developed, and O.D. D is also high.
Δ: Slightly lacking in color development, O.D. D is low.
X: The color is darkened.
[0088]
(3) Scratch
After leaving the image obtained by printing for one day, it was evaluated by rubbing with a hand or erasing with an eraser.
：: Even if the eraser is strongly rubbed five times, characters and solid images hardly disappear and the hands are not stained.
Δ: Slightly inferior level.
X: The level which has a clear problem substantially.
[0089]
(4) Water resistance
The sample printed on Xerox 4024 paper was immersed in tap water for 5 minutes, and the change in the optical density of the printed matter before and after the treatment was represented by the residual ratio.
：: Remaining rate is 98% or more
△: 90-97% residual rate
×: Residual rate is 89% or less
[0090]
[Table 1]

[0091]
【The invention's effect】
According to the present invention, irrespective of the type of the recording medium, especially for OHP sheets and special papers and films having glossiness, the print quality, good color development, and abrasion, water resistance It is possible to provide an excellent recording liquid and an ink jet recording excellent in ejection stability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a head section of an ink jet recording apparatus.
FIG. 2 is a longitudinal sectional view of a head section of the ink jet recording apparatus.
FIG. 3 is an external perspective view of a head obtained by multiplying the head shown in FIGS. 1 and 2;
FIG. 4 is a perspective view illustrating an example of an ink jet recording apparatus.
FIG. 5 is a vertical sectional view of the ink cartridge.
FIG. 6 is a perspective view of a recording unit.
[Explanation of symbols]
1 Ink tank
2 Inkjet recording head
3 Inkjet recording device
13 head
14 grooves
15 Heating head
16 Protective film
17-1, 17-2 Aluminum electrode
18 Heating resistor layer
19 Thermal storage layer
20 substrates
21 ink
22 Discharge orifice
23 Meniscus
24 Recording droplets
25 Recording material
26 Multi Groove
27 glass plate
28 Heating head
40 ink storage section
42 stopper
44 Ink absorber
45 ink cartridge
51 Paper feed unit
52 Paper feed roller
53 Paper ejection roller
61 Wiping member
62 cap
63 Ink absorber
64 Discharge recovery section
65 Recording Head
66 carriage
70 Recording unit
71 Orifice tip
72 Atmospheric communication port
73 substrate

Claims (12)

In a recording liquid containing at least a pigment, an alkali-soluble resin, and water, (a) the pigment has an average particle size of 0.05 to 0.3 μm and a content of 1 to 10% by weight, and (b) ) The alkali-soluble resin is used in such a manner that the neutralization ratio of the alkali-soluble resin is 100 to 120%, the weight average molecular weight is 20,000 or less, and the content thereof is 3.4 to 5.2 times that of the pigment. A recording liquid characterized in that: The recording liquid according to claim 1, further comprising a basic substance that dissolves the alkali-soluble resin in water. 3. The recording liquid according to claim 2, wherein the basic substance is an alkanolamine. The recording liquid according to any one of claims 1 to 3, wherein the recording liquid is for inkjet. 5. An ink jet recording method, comprising: performing recording by attaching a droplet of the recording liquid according to claim 4 formed by an ink jet method to a recording material. The ink jet recording method according to claim 5, wherein the ink jet method is a method in which thermal energy acts on a recording liquid. A recording liquid cartridge comprising a recording liquid storage section that stores the recording liquid according to any one of claims 1 to 4. A recording unit, comprising: a recording liquid storage unit that stores the recording liquid according to claim 4; and a head unit that discharges the recording liquid as droplets. The recording unit according to claim 8, wherein the recording liquid is ejected by applying thermal energy to the recording liquid in the head unit. An ink jet recording apparatus comprising: the recording liquid according to claim 4; and a recording head that discharges the recording liquid as droplets. A method for producing a recording liquid containing 1 to 10% by weight of a pigment having an average particle diameter of 0.05 to 0.3 μm based on the total amount of the recording liquid, wherein (i) a step of preparing a pigment dispersion containing the pigment And (ii) mixing a solution of an alkali-soluble resin having a weight average molecular weight of 20,000 or less with the pigment dispersion, wherein the alkali-soluble resin solution has a neutralization ratio of 100 A method for producing a recording liquid, wherein the pigment is used in an amount of from 3.4 to 5.2 times the pigment in an amount of from 3.4 to 5.2 times the pigment. The method for producing a recording liquid according to claim 11, wherein the pigment dispersion liquid has the pigment dispersed in an aqueous medium with a surfactant.

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