JP4165861B2 - Ink-jet ink composition and recording method using the same - Google Patents

Description

Ｒ³：炭素数５〜１６の分岐したアルキル基
Ｍ³：アルカリ金属、第４級アンモニウム、第４級ホスホニウム、又はアルカノールアミン
【００３６】
【化２】

Ｒ：分岐しても良い炭素数６〜１４の炭素鎖
ｋ：５〜２０の整数
【００３７】
Ｒ⁵−(ＯＣＨ₂ＣＨ₂)_lＯＨ （５）
Ｒ⁵：分岐しても良い炭素数６〜１４の炭素鎖
ｌ ：５〜２０の整数
【００３８】
【化３】

Ｒ' ：炭素数６〜１４の炭素鎖
ｍ、ｎ：０〜２０の整数
【００３９】
【化４】

【００４０】
本発明のインクには上記色材粒子、溶媒、分散剤の他に従来より知られている添加剤を加えることができる。
例えば、防腐防黴剤としてはデヒドロ酢酸ナトリウム、ソルビン酸ナトリウム、２−ピリジンチオール−１−オキサイドナトリウム、安息香酸ナトリウム、ペンタクロロフェノールナトリウム等が本発明に使用できる。
【００４１】
ｐＨ調整剤としては、調合されるインクに悪影響をおよぼさずにｐＨを７以上に調整できるものであれば、任意の物質を使用することができる。
その例として、ジエタノールアミン、トリエタノールアミン等のアミン、水酸化リチウム、水酸化ナトリウム、水酸化カリウム等のアルカリ金属元素の水酸化物、水酸化アンモニウム、第４級アンモニウム水酸化物、第４級ホスホニウム水酸化物、炭酸リチウム、炭酸ナトリウム、炭酸カリウム等のアルカリ金属の炭酸塩等が挙げられる。
【００４２】
キレート試薬としては、例えば、エチレンジアミン四酢酸ナトリウム、ニトリロ三酢酸ナトリウム、ヒドロキシエチルエチレンジアミン三酢酸ナトリウム、ジエチレントリアミン五酢酸ナトリウム、ウラミル二酢酸ナトリウム等がある。
【００４３】
防錆剤としては、例えば、酸性亜硫酸塩、チオ硫酸ナトリウム、チオジグリコール酸アンモン、ジイソプロピルアンモニウムニトライト、四硝酸ペンタエリスリトール、ジシクロヘキシルアンモニウムニトライト等がある。
【００４４】
その目的に応じて水溶性紫外線吸収剤、水溶性赤外線吸収剤等を添加することができる。
【００４５】
本発明のインク組成物を収容したインクカートリッジ及びインクカートリッジを具備するインクジェット記録装置について、添付図面を参照して説明するが、以下は構成例のひとつに過ぎず、本発明になんら限定を加えるものではない。
【００４６】
図１は本発明のインク組成物を収容した記録液収容部を備えたインクカートリッジを搭載するシリアル型インクジェット記録装置の機構部の概略正面図である。
このインクジェット記録装置の機構部は、両側の側板１、２間に主支持ガイドロッド３及び従支持ガイドロッド４を略水平な位置関係で横架し、これらの主支持ガイドロッド３及び従支持ガイドロッド４でキャリッジユニット５を主走査方向に摺動自在に支持している。キャリッジユニット５には、それぞれイエロー（Ｙ）インク、マゼンタ（Ｍ）インク、シアン（Ｃ）インク、ブラック（Ｂｋ）インクをそれぞれ吐出する４個のヘッド６を、その吐出面（ノズル面）６ａを下方に向けて搭載し、またキャリッジユニット５のヘッド６の上側には４個のヘッド６に各々インクを供給するための各色のインク供給体である４個のインクカートリッジ７Ｙ、７Ｍ、７Ｃ、７Ｂｋを交換可能に搭載している。
【００４７】
そして、キャリッジユニット５は主走査モータ８で回転される駆動プーリ（駆動タイミングプーリ）９と従動プーリ（アイドラプーリ）１０との間に張装したタイミングベルト１１に連結して、主走査モータ８を駆動制御することによってキャリッジ５、即ち４個のヘッド６を主走査方向に移動するようにしている。
【００４８】
また、側板１、２をつなぐ底板１２上にサブフレーム１３、１４を立設し、このサブフレーム１３、１４間に用紙１６を主走査方向と直交する副走査方向に送るための搬送ローラ１５を回転自在に保持している。そして、サブフレーム１４側方に副走査モータ１７を配設し、この副走査モータ１７の回転を搬送ローラ１５に伝達するために、副走査モータ１７の回転軸に固定したギヤ１８と搬送ローラ１５の軸に固定したギヤ１９とを備えている。
【００４９】
さらに、側板１とサブフレーム１３との間には、ヘッド６の信頼性維持回復機構（以下、「サブシステム」という。）２１を配置している。サブシステム２１は、各ヘッド６の吐出面をキャッピングする４個のキャップ手段２２をホルダ２３で保持し、このホルダ２３をリンク部材２４で揺動可能に保持して、キャリッジユニット５の主走査方向の移動でホルダ２３に設けた係合部２５にキャリッジユニット５が当接することで、キャリッジユニット５の移動に従ってホルダ２３がリフトアップしてキャップ手段２２でインクジェットヘッド６の吐出面６ａをキャッピングし、キャリッジユニット５が印写領域側へ移動することで、キャリッジユニット５の移動に従ってホルダ２３がリフトダウンしてキャップ手段２２がインクジェットヘッド６の吐出面６ａから離れるようにしている。
【００５０】
なお、キャップ手段２２は、それぞれ吸引チューブ２６を介して吸引ポンプ２７に接続すると共に、大気開放口を形成して、大気開放チューブ及び大気開放バルブを介して大気に連通している。また、吸引ポンプ２７は吸引した廃液を、ドレインチューブ等を介して図示しない廃液貯留槽に排出する。
【００５１】
さらに、ホルダ２３の側方には、インクジェットヘッド６の吐出面６ａをワイピングする繊維部材、発泡部材或いはゴム等の弾性部材からなるワイピング手段であるワイパブレード２８をブレードアーム２９に取付け、このブレードアーム２９は揺動可能に軸支し、図示しない駆動手段で回動されるカムの回転によって揺動させるようにしている。
【００５２】
次に、インクカートリッジ７について図２、図３を参照して説明する。ここで、図２は記録装置に装填する前のインクカートリッジの外観斜視図、図３はインクカートリッジの正断面図である。
インクカートリッジ７は、図３に示すように、カートリッジ本体４１内に所要の色のインクを吸収させたインク吸収体４２を収容してなる。カートリッジ本体４１は、上部に広い開口を有するケース４３の上部開口に上蓋部材４４を接着又は溶着して形成したものであり、例えば樹脂成型品からなる。また、インク吸収体４２は、ウレタンフォーム体等の多孔質体からなり、カートリッジ本体４１内に圧縮して挿入した後、インクを吸収させている。
【００５３】
カートリッジ本体４１のケース４３底部には記録ヘッド６へインクを供給するためのインク供給口４５を形成し、このインク供給口４５内周面にはシールリング４６を嵌着している。また、上蓋部材４４には大気開放口４７を形成している。
そして、カートリッジ本体４１には、装填前の状態で、インク供給口４５を塞ぐとと共に装填時や輸送時などのカートリッジ取扱い時、或いは真空包装時による幅広側壁に係る圧力でケース４３が圧縮変形されて内部のインクが漏洩することを防止するため、キャップ部材５０を装着している。
【００５４】
また、大気開放口４７は、図２に示すように、酸素透過率が１００ｍｌ／ｍ²以上のフィルム状シール部材５５を上蓋部材４４に貼着してシールしている。このシール部材５５は大気開放口４７と共にその周囲に形成した複数本の溝４８をもシールする大きさにしている。このように大気開放口４７を酸素透過率が１００ｍｌ／ｍ²以上のシール部材５５でシールすることで、インクカートリッジ７を透気性のないアルミラミネートフィルム等の包装部材を用いて減圧状態で包装することにより、インク充填時やインク吸収体４２とカートリッジ本体４１との間に生じる空間Ａ（図３参照）にある大気のためにインク中に気体が溶存したときでも、シール部材５５を介してインク中の空気が真空度の高いカートリッジ本体４１外の包装部材との間の空間に排出され、インクの脱気度が向上する。
【００５５】
また、図４には、本発明のインク組成物を収容したインク収容部と、インク滴を吐出させるためのヘッド部を備えたインクカートリッジの構成例を示し、説明する。
【００５６】
すなわち、記録ユニット３０は、シリアルタイプのものであり、インクジェットヘッド６と、このインクジェットヘッド６に供給されるインクを収容するインクタンク４１と、このインクタンク４１内を密閉する蓋部材とで主要部が構成される。インクジェットヘッド６には、記録液を吐出するための多数のノズル３２が形成されている。インクはインクタンク４１から、図示しないインク供給管を介して、やはり図示しない共通液室へと導かれ、電極３１より入力される記録装置本体からの電気信号に応じて、ノズル３２より吐出される。このようなタイプの記録ユニットは、構成上、安価に製造できるタイプのヘッド、いわゆるサーマル方式、バブル方式と呼ばれる、熱エネルギーを駆動の動力源とするヘッドに適した構造である。また、本発明のインク組成物は、熱エネルギーを作用させてインク吐出を行なう記録方法のみならず、力学的エネルギーを作用させてインク吐出を行なう記録方法においても適している。
【００５７】
ここでは、前述のようなシリアル型インクジェット記録装置を説明したが、本発明のインク組成物は、ノズルを千鳥など任意の配列で、目的とする画像の解像度と同じか数分の１程度の密度に集積し、記録媒体の幅以上に配列させた、いわゆるラインヘッドを有する記録装置に適用することも可能である。
【００５８】
また、ここでいう記録装置とは、ＰＣやデジタルカメラ用の出力プリンタのみならず、ファックスやスキャナ、電話などと組み合わせた複合的な機能を有する装置であっても構わない。
【００５９】
以下、実施例、参考例、比較例によって本発明をさらに具体的に説明する。
参考例１
＜ミルベース処方＞
シリカ／カーボンブラック複合顔料（戸田工業（株）、１次粒子径１８ｎｍ）
１３重量部
ジアルキルスルホコハク酸エステルＮａ塩（アニオン系界面活性剤）
（アデカコールＥＣ−４５００、旭電化工業（株）） ７重量部
イオン交換水 ８０重量部
＜インク処方＞
ミルベース １００重量部
グリセリン １５重量部
ジエチレングリコール ２５重量部
２，２，４−トリメチル−１，３−ペンタンジオール ３重量部
下記式で表される界面活性剤 ３重量部
Ｃ₁₃Ｈ₂₇−Ｏ−(ＣＨ₂ＣＨ₂Ｏ)₃ＣＨ₂ＣＯＯＮａ
プロキセルＬＶ（防腐防黴剤） ０．２重量部
イオン交換水 ５４重量部
【００６０】
ジアルキルスルホコハク酸エステルＮａ塩をイオン交換水に溶解し、上記顔料を混合して充分に湿潤したところで、混練装置としてダイノーミル ＫＤＬ Ａ型（ＷＡＢ製）にφ０．５ｍｍジルコニアビーズを充填し、２０００ｒｐｍで３時間混練を行なってミルベースを得た。
次に、グリセリン、ジエチレングリコール、２，２，４−トリメチル−１，３−ペンタンジオール、上記式で表される界面活性剤、プロキセルＬＶをイオン交換水に溶解してビヒクルを作製し、ミルベースと混合した後、１μｍのテフロン（登録商標）製フィルターでろ過することで、インクジェット用ブラックインクを得た。
【００６１】
参考例２
＜ミルベース処方＞
シリカ／フタロシアニンＰＢ１５：３複合顔料
（戸田工業（株）、１次粒子径１６ｎｍ） １３重量部
アルキルベンゼンスルホン酸Ｎａ塩（アニオン系界面活性剤）
（ネオペレックスＮｏ．２５、花王（株）） ７重量部
イオン交換水 ８０重量部
＜インク処方＞
ミルベース １００重量部
グリセリン １０重量部
１，６−ヘキサンジオール ３０重量部
２−エチル−１，３−ヘキサンジオール ４重量部
下記式で表される界面活性剤 ２重量部
Ｃ₁₃Ｈ₂₇−(ＯＣＨ₂ＣＨ₂)₈ＯＨ
プロキセルＬＶ（防腐防黴剤） ０．２重量部
イオン交換水 ５４重量部
上記ミルベース処方を用いて、参考例１と同様の方法でミルベースを作製し、次に、グリセリン、１，６−ヘキサンジオール、２−エチル−１，３−ヘキサンジオール、上記式で表される界面活性剤、プロキセルＬＶをイオン交換水に溶解してビヒクルを作製し、ミルベースと混合した後、１μｍのテフロン（登録商標）製フィルターでろ過することで、インクジェット用シアンインクを得た。
【００６２】
実施例１
＜ミルベース処方＞
シリカ／ジスアゾイエロー複合顔料（戸田工業（株）、１次粒子径１７ｎｍ）
１３重量部
下記式で表されるアニオン系界面活性剤 ３重量部
Ｃ₁₀Ｈ₂₁−Ｏ−(ＣＨ₂ＣＨ₂Ｏ)₁₇ＳＯ₃ＮＨ₄
イオン交換水 ８０重量部
＜インク処方＞
ミルベース １００重量部
グリセリン １０重量部
１，３−ブタンジオール ３０重量部
２−エチル−１，３−ヘキサンジオール ４重量部
上記一般式（７）記載のアセチレン系界面活性剤（ｐ＋ｑ＝１０）
（サーフィノール４６５、日信化学（株）） ４重量部
プロキセルＬＶ（防腐防黴剤） ０．２重量部
イオン交換水 ５４重量部
上記ミルベース処方を用いて、参考例１と同様の方法でミルベースを作製し、次に、グリセリン、１，３−ブタンジオール、２−エチル−１，３−ヘキサンジオール、上記一般式（７）で表される界面活性剤、プロキセルＬＶをイオン交換水に溶解してビヒクルを作製し、ミルベースと混合した後、１μｍのテフロン（登録商標）製フィルターでろ過することで、インクジェット用イエローインクを得た。
【００６３】
参考例３
＜ミルベース処方＞
シリカ／キナクリドンＰＲ１２２複合顔料
（戸田工業（株）、１次粒子径１６ｎｍ） １３重量部
ポリカルボン酸Ｎａ塩（スチレン／マレイン酸共重合物の変性物）
（アニオン系界面活性剤）（フローレンＴＧ−７５０、共栄社化学（株））
７重量部
イオン交換水 ８０重量部
上記ミルベース処方を用いて、参考例１と同様の方法でミルベースを作製し、参考例２と同様のインク処方と方法を用いて、インクジェット用マゼンタインクを得た。
【００６４】
比較例１
＜ミルベース処方＞
シリカ／キナクリドンＰＲ１２２複合顔料
（戸田工業（株）、１次粒子径１６ｎｍ） １３重量部
ノニルフェノールエチレンオキサイド付加物（ノニオン系界面活性剤）
７重量部
イオン交換水 ８０重量部
上記ミルベース処方を用いて、参考例１と同様の方法でミルベースを作製し、参考例２と同様のインク処方と方法を用いて、インクジェット用マゼンタインクを得た。
【００６５】
比較例２
＜ミルベース処方＞
フタロシアニンＰＢ１５：３
（大日精化工業（株）、ＥＣＢ−３０１） １３重量部
アルキルベンゼンスルホン酸Ｎａ塩（アニオン系界面活性剤）
（ネオペレックスＮｏ．２５、花王（株）） ７重量部
イオン交換水 ８０重量部
上記ミルベース処方を用いて、参考例１と同様の方法でミルベースを作製し、参考例２と同様のインク処方と方法を用いて、インクジェット用シアンインクを得た。
【００６６】
比較例３
＜インク処方＞
Ａｃｉｄ Ｒｅｄ ５２（水溶性染料） ３重量部
グリセリン ５重量部
ジエチレングリコール １５重量部
２−エチル−１、３−ヘキサンジオール １重量部
上記一般式（７）に記載のアセチレン系界面活性剤（ｐ＋ｑ＝１０）
（サーフィノール４６５、日信化学（株）） ２重量部
デヒドロ酢酸ナトリウム ０．２重量部
イオン交換水 ７４重量部
上記インク処方の組成物を撹拌溶解した後、ｐＨが１０になるように水酸化リチウム１０％水溶液にて調整し、これを０．２０μｍのテフロン（登録商標）フィルターにて濾過しインクジェット用マゼンタインクを得た。
【００６７】
得られた実施例、参考例及び比較例のインクを用い、評価を行なった。評価項目、評価方法を以下に記載し、結果を表１に示す。
（１）径測定
実施例、参考例及び比較例における、インクジェット用インクの色材粒子の体積平均粒径を、マイクロトラックＵＰＡを用いて測定した。
【００６８】
（２）表面張力測定
実施例、参考例及び比較例における、インクジェット用インクの表面張力を、協和界面科学製ＣＢＶＰ−Ｚ型を用いて測定した。
【００６９】
（３）吐出安定性評価
実施例、参考例及び比較例における、インクジェット用インクを、力学的エネルギー作用させてインクの吐出を行なうリコー製インクジェットプリンターＩＰＳｉＯ Ｊｅｔ３００に充填し、プリンター動作中にキャップ、クリーニング等を行わないでどれだけ印字休止しても復帰できるかを調べ、どれだけの時間（秒）で噴射方向がずれるか、あるいは吐出液滴の重量が変化するかをもって、その信頼性を以下の評価基準で判定した。
＜評価基準＞
◎：６００秒以上
○：１２０秒以上、６００秒未満
△：３０秒以上、１２０秒未満
×：３０秒未満
【００７０】
（４）明度測定
実施例、参考例及び比較例における、インクジェット用インクを、リコー製インクジェットプリンターＩＰＳｉＯ Ｊｅｔ３００に充填し、ワンパスでベタを印字した。印刷試験用紙は下記の普通紙と光沢紙を使用して印字乾燥後、明度を反射型カラー分光測色濃度計（Ｘ−Ｒｉｔｅ社製）で測定した。標準色（Japan color ver.２）の明度の値（イエロー：８７．２７、マゼンタ：４４．６９、シアン：５１．３６）に対して、測定した明度の値の比率を算出し、下の評価基準にしたがって評価した。
＜印刷試験用紙＞
普通紙：マイペーパー（株式会社ＮＢＳリコー製）
光沢紙：ＭＣ光沢紙（エプソン）
＜評価基準＞
◎：１．０以上
○：０．８以上 １．０未満
△：０．６以上 ０．８未満
×：０．６未満
【００７１】
（５）耐光性評価
明度測定と同様の方法で作製した画像サンプルを、アトラス製ウェザオメータＣｉ３５ＡＷを用いて、７０℃、５０％ＲＨ、ブラックパネル温度８９℃環境にて、屋外太陽光近似のキセノン放射照度０．３５Ｗ／ｍ²（３４０ｎｍ）で２４時間照射し、前後の退色、色変化を以下の評価基準で判定した。
＜評価基準＞
◎：ほとんど変化がないもの
○：変化の少ないもの
△：変化は認められるが許容できるもの
×：退色、色変化の大きいもの
【００７２】
【表１】

【００７３】
表１の結果から、本発明によるインクジェット用インク組成物の色材粒子の分散粒子径はすべて１００ｎｍ以下であり、上記一般式（１）で表されるアニオン系界面活性剤又は特定のポリカルボン酸塩を分散剤として用いることで、さらに１次粒子に近い状態まで微分散することが可能となり、吐出安定性も高いことがわかる。さらに、有機顔料インクに匹敵する耐光性を保持しつつ、色調は染料インク並の明るさを持つインクジェット用インク及びそれを用いた記録物を得ることが可能であることがわかる。
【００７４】
【発明の効果】
本発明のインク組成物を用いることで分散粒子を極めて微細に安定化することができるため、吐出安定性に優れたインクジェット用インク、それを用いた記録方法及び記録物を提供することが可能となる。
さらに、本発明のインク組成物を用いることで顔料分散インク特有の耐光性に優れた特性を損なうことがなく、染料インクに匹敵する色調に優れたインクジェット用インク、それを用いた記録方法及び記録物を提供することが可能となる。
【図面の簡単な説明】
【図１】本発明を適用したインク組成物を収容するインクカートリッジを搭載するシリアル型インクジェット記録装置の構成例を示す概略正面図である。
【図２】記録装置に装填する前のインクカートリッジの外観斜視図である。
【図３】インクカートリッジの正断面図である。
【図４】記録ヘッドと一体化されたインクカートリッジの外観斜視図である。
【符号の説明】
１、２ 側板
３ 主支持ガイドロッド
４ 従支持ガイドロッド
５ キャリッジユニット
６ インクジェットヘッド
６ａ 吐出面
７、７Ｙ、７Ｍ、７Ｃ、７Ｂｋ インクカートリッジ
８ 主走査モータ
９ 駆動プーリ
１０ 従動プーリ
１１ タイミングベルト
１２ 底板
１３、１４ サブフレーム
１５ 搬送ローラ
１６ 用紙
１７ 副走査モータ
１８、１９ ギア
２１ サブシステム
２２ キャップ手段
２３ ホルダ
２４ リンク部材
２５ 係合部
２６ 吸引チューブ
２７ 吸引ポンプ
２８ ワイパーブレード
２９ ブレードアーム
３０ 記録ユニット
３１ 電極
３２ ノズル
４１ カートリッジ本体（インクタンク）
４２ インク吸収体
４３ ケース
４４ 上蓋部材
４５ インク供給口
４６ シールリング
４７ 大気開放口
４８ 溝
５０ キャップ部材
５５ フィルム状シール部材
Ａ 空間[0001]
[Technical field to which the invention belongs]
  The present inventionFor inkjetPigment ink suitable for printing, recording method and recorded matter using the same, excellent ink storage stability, particularly excellent clogging of the head without clogging during printing, and image fastness such as water resistance and light resistance Images with excellent color tone can be obtained not only on dedicated recording paper but also on plain paperFor inkjetThe present invention relates to a pigment ink.
[0002]
[Prior art]
Inkjet printers have been remarkably popular due to their low noise and low running costs, and color printers that can print on plain paper have been actively introduced into the market. However, all required properties such as color reproducibility, durability, light resistance, image drying, character bleeding (feathering), color boundary bleeding (color bleed), double-sided printability, and ejection stability It is very difficult to satisfy, and the ink to be used is selected from the characteristics that are given priority depending on the application.
[0003]
Ink used for ink jet recording is generally composed mainly of water and contains a colorant and a wetting agent such as glycerin for the purpose of preventing clogging. As the colorant, a dye is used because of its excellent color developability and stability. However, the light resistance, water resistance and the like of an image obtained using a dye-based ink are inferior. The water resistance is improved to some extent by improving the ink jet recording paper having an ink absorbing layer, but the plain paper is not satisfactory.
[0004]
In recent years, in order to improve these problems, pigments such as organic pigments and carbon black are made fine particles using surfactants and dispersants instead of dyes, and dispersed in a medium such as water as a colorant. The pigment ink to be used has been studied. Japanese Patent Application Laid-Open Nos. 9-263720 and 9-263722 propose a method for improving discharge stability by making organic pigments into a fine particle having a particle diameter of 50 nm or less using a specific dispersant. However, it is impossible to subdivide the organic pigment primary particles with any dispersant, and it is very difficult to reduce the primary particle size of the organic pigment to 50 nm or less without deterioration in color tone. I must say that there is.
[0005]
In ink jet recording, since stable ink droplet ejection is required from the fine nozzles of the ink jet recording head, it is necessary that the ink is not solidified by drying the orifice of the ink jet recording head. However, when the ink in which the organic pigment is dispersed is used for ink jet recording, clogging, non-ejection of the ink, or the like may occur. In particular, when printing is suspended for a long period of time, clogging of nozzles and the like is likely to occur, and thickened ink accumulates in the maintenance mechanism such as the nozzle cap and the suction tube, which may impair the function of the maintenance mechanism. There was something. In addition, when printing is paused, or when a printing pause period is established for a nozzle corresponding to a blank during printing of a blank document or image, printing failure (intermittent) due to disturbance of the ink droplet ejection direction. There were many problems such as defective discharge.
[0006]
As another dispersion method, there is a so-called self-dispersion type pigment ink that can be stably dispersed without using a dispersant. As a black pigment ink, a so-called self-dispersing carbon black that can be stably dispersed without using a dispersant by introducing a hydrophilic group on the surface of carbon has been developed. Furthermore, color pigments that can be dispersed stably without using a dispersant have also been developed in color pigment-based inks. However, these self-dispersing pigment inks have low color image saturation on plain paper and poor scratch resistance on dedicated glossy paper. When a resin emulsion is added to improve the scratch resistance, there is a disadvantage that the dispersion stability of the ink is lowered and the ejection stability is impaired.
[0007]
As a method for solving the above problems, an inkjet ink using a so-called microcapsule or emulsion type dispersion in which pigment particles are coated with a resin has been proposed. Although the dispersion state is stable over a long period of time because the pigment is firmly covered with the resin, and the instability of ejection has been improved, the dispersed particle size is not limited even when the pigment having a primary particle size of 50 to 100 nm is coated. It is difficult to reduce the thickness to 100 nm or less, and it must be said that it is still unstable for practical use from the viewpoint of ejection stability.
[0008]
In recent years, composite pigments have been proposed in which inorganic pigment particles are covered with an organic pigment. In JP-A-11-323174, JP-A-11-338191, and JP-A-2000-351914, a composite pigment in which an inorganic pigment is coated with polysiloxane or organosilane and carbon black particles are adhered to the surface thereof is disclosed. The black toner used has been proposed. JP-A No. 2001-172526 proposes a yellow pigment in which a yellow organic pigment is adhered to the surface of an inorganic pigment coated with polysiloxane or organosilane, and JP-A Nos. 2001-181533 and 2001-226609. The publication proposes a green pigment to which a blue organic pigment is attached. The core material of the inorganic pigment used in these is 0.1 to 2.0 μm, which is too large for use in inkjet. Particles that can be used in inkjet are desirably 200 nm or less in average particle size for the reason that nozzles are not clogged, and are desirably 100 nm or less in average particle size for practical use. If inorganic pigment particles of about 5 to 50 nm are used as the core material of this composite pigment, it is possible to obtain a colored pigment of less than 100 nm even in a state where it is coated with an organic pigment. Pigment coloring materials have already been put into practical use.
[0009]
Moreover, in JP-A-11-166127 and JP-A-2001-192582, a dye is attached to the surface of a metal oxide and further covered with an organic compound having an ionic group, so that the particle size is nanometer size. It has been proposed that a color material having a uniform particle diameter is obtained and used for an inkjet ink. Although the water resistance is improved as compared with the ink using the dye, the light resistance is worse than that of the dye ink, and it does not endure actual use.
[0010]
[Problems to be solved by the invention]
  The present invention eliminates such conventional drawbacks,For inkjetAn ink composition, a recording method using the ink composition, and a recorded matter are provided. In particular, even when printing on plain paper using an ink jet recording method, it has excellent ejection stability and storage stability, and color reproducibility of a color image. And can provide image robustness such as water resistance and light resistanceFor inkjetIt is an object of the present invention to provide a pigment ink composition, a recording method using the same, and a recorded matter.
[0011]
[Means for Solving the Problems]
  As a result of intensive studies in order to solve the above problems, the present inventor has arrived at the present invention. That is, the present invention includes at least coloring material particles obtained by coating inorganic pigment particles with an organic pigment or carbon black, a dispersant, and water, and the dispersant is an anionic surfactant.For inkjetInk composition.
[0012]
Color material particles in which inorganic pigment particles used in the present invention are coated with an organic pigment or carbon black are a method of depositing organic pigments in the presence of inorganic pigment particles, or mechanically kneading inorganic pigments and organic pigments. It can be produced by a method or the like. If necessary, it is possible to improve the adhesion between the inorganic pigment and the organic pigment by providing a layer of an organosilane compound generated from polysiloxane and alkylsilane between the inorganic pigment and the organic pigment.
[0013]
Examples of the inorganic pigment include titanium dioxide, silica, alumina, iron oxide, iron hydroxide, tin oxide, and the like. The particle shape preferably has a small aspect ratio, and most preferably spherical. In addition, the color of the inorganic pigment is preferably transparent or white when the color material is adsorbed on the surface, but when the black color material is adsorbed on the surface, a black inorganic pigment may be used. I do not care. The primary particle diameter is preferably 100 nm or less, and more preferably 5 to 50 nm.
[0014]
Examples of organic pigments include aniline black as a black pigment, and examples of color pigments include anthraquinone, phthalocyanine blue, phthalocyanine green, diazo, monoazo, pyranthrone, perylene, heterocyclic yellow, quinacridone, and (thio) indigoid. . Among these, aniline black, phthalocyanine pigments, quinacridone pigments, monoazo yellow pigments, disazo yellow pigments, and heterocyclic yellow pigments are excellent in terms of color development.
[0015]
A typical example of the phthalocyanine pigment is copper phthalocyanine blue and a derivative thereof (Pigment Blue 15). Representative examples of quinacridone pigments include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19 and Pigment Violet 42. is there. Typical examples of the monoazo yellow pigment are pigment yellow 74, pigment yellow 109, pigment yellow 128, and pigment yellow 151. Representative examples of the disazo yellow pigment include pigment yellow 14, pigment yellow 16, and pigment yellow 17. Representative examples of the heterocyclic yellow pigment are pigment yellow 117 and pigment yellow 138. Examples of other suitable colored pigments are described in The Color Index, 3rd edition (The Society of Dyers and Colorists, 1982).
[0016]
The weight ratio of the inorganic pigment particles and the organic pigment or carbon black, which is a color material, is preferably 3: 1 to 1: 3. Since transparency and a color tone worsen, it is more preferably 3: 2 to 1: 2.
[0017]
Color material particles obtained by coating inorganic pigment particles used in the present invention with organic pigments or carbon black include silica / carbon black composite material manufactured by Toda Kogyo Co., Ltd., silica / phthalocyanine PB15: 3 composite material, silica / disazo yellow composite material. Materials, such as silica / quinacridone PR122 composite material, have a small primary average particle size and can be suitably used.
[0018]
For example, when inorganic pigment particles having a primary particle diameter of 20 nm are coated with an equal amount of organic pigment, the primary particle diameter of the pigment is about 25 nm. If a suitable dispersing agent is used for this and it can disperse | distribute to a primary particle, the very fine pigment dispersion ink with a dispersion particle diameter of 25 nm can be produced. However, in this composite pigment, not only the organic pigment on the surface contributes to the dispersion, but also the properties of the inorganic pigment at the center appear through a thin layer of organic pigment with a thickness of about 2.5 nm. The selection of a dispersant that can be stabilized is very difficult. However, after intensive studies on this point, an anionic surfactant is suitable for stably dispersing the inorganic-organic composite pigment, and particularly, a compound represented by the following general formula (1), or an alkali metal, It has been found that if a polycarboxylate neutralized with ammonium, phosphonium, or alkanolamine is used, the inorganic-organic composite pigment can be stably dispersed to near the primary particles.
R¹-O- (CH₂CH₂O)_j-SO_ThreeM¹            (1)
R¹: Alkyl group having 5 to 15 carbon atoms which may be branched
j: an integer from 10 to 20
M¹: Alkali metal, ammonium, phosphonium, or alkanolamine
[0019]
Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, polyoxyethylene alkyl ether sulfate salts, oleates, polycarboxylic acids and their salts, alkylbenzene sulfonic acids Examples thereof include salts, maleic acid dialkyl ester sulfonic acids and salts thereof. Moreover, as a particularly useful specific example of the compound represented by the general formula (1),
C_TenH_{twenty one}-O- (CH₂CH₂O)₁₇SO_ThreeM¹
M¹: NH_FourOr Na
Among these polycarboxylates, particularly useful ones include modified products of styrene / maleic acid copolymer (for example, trade name: Floren TG-750W, Kyoeisha Chemical Co., Ltd.).
[0020]
Dissolve the dispersant in an aqueous medium, then add a coloring material containing the inorganic pigment particles as an organic pigment and thoroughly moisten the mixture, then use a ball such as a bead mill or ball mill at high speed with a homogenizer. A dispersion can be produced by a method using a conventional kneading and dispersing machine, a kneading and dispersing machine using a shearing force such as a roll mill, an ultrasonic dispersing machine or the like. However, after such a kneading and dispersing step, coarse particles are often contained, which may cause clogging of the ink jet nozzle and the supply path. Therefore, particles having a particle diameter of 1 μm or more using a filter or a centrifuge. Need to be removed.
[0021]
According to the preferable aspect of this invention, it is preferable to use a dispersing agent in the ratio range of 1 to 100 weight% with respect to a pigment color material, More preferably, it is 10 to 50 weight%. If the amount of the dispersant is small, the pigment cannot be sufficiently miniaturized. If the amount of the dispersant is too large, excess components that are not adsorbed on the pigment affect the ink properties, causing image bleeding, water resistance, and abrasion resistance. It will cause deterioration of the sex. Further, the volume average particle diameter of the colorant fine particles of the present invention is preferably 5 to 100 nm, more preferably 10 to 80 nm in the ink. The content of the dispersed fine particles in the ink is preferably about 2 to 20% by weight, more preferably 4 to 15% by weight, based on the solid content of the pigment and dispersant combined.
[0022]
Furthermore, the printed matter of the ink of the present invention exhibits a coloring power of nearly 70 to 90% even though the colorant such as organic pigment or carbon black contains only about half of the color material of the organic pigment or carbon black alone. Therefore, by increasing the pigment concentration in the ink by about 11 to 43%, it is possible to obtain a printed matter having an image density comparable to that of an organic pigment or carbon black alone. Further, in the color printed matter, there is an effect of increasing the brightness (brightness) and vividness (saturation) of the color by using the composite pigment of the present invention, and particularly for printing a photographic image as an ink jet recording medium. The glossy paper used has a strong effect, and a vivid image that is inferior to that of printed matter using dye ink can be obtained.
[0023]
The ink composition of the present invention uses water as a liquid medium. For the purpose of preventing the ink from drying and improving the dispersion stability, the following wetting agent and water-soluble organic compound are used. A solvent may be used. A plurality of these wetting agents and water-soluble organic solvents may be used in combination.
[0024]
Specific examples of the wetting agent and the water-soluble organic solvent include the following.
Glycerin, 1,3-butanediol, triethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, trimethylolpropane, trimethylolethane, ethylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, tetraethylene glycol, hexylene glycol , Polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, Polyhydric alcohols such as petriol;
Polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether;
Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;
Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone;
Amides such as formamide, N-methylformamide, N, N-dimethylformamide;
Amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine;
Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol;
Propylene carbonate, ethylene carbonate and the like.
[0025]
Among these organic solvents, diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol, 1,5-pentane Diol, 2-pyrrolidone and N-methyl-2-pyrrolidone are preferred. These are excellent in solubility and prevention of poor jetting characteristics due to water evaporation.
[0026]
The other wetting agent preferably contains sugar. Examples of saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, Examples include lactose, sucrose, trehalose and maltotriose. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose.
[0027]
In addition, derivatives of these saccharides include reducing sugars of the aforementioned saccharides (for example, sugar alcohol (general formula HOCH₂(CHOH)_nCH₂OH (wherein n represents an integer of 2 to 5). ), Oxidized sugar (eg, aldonic acid, uronic acid, etc.), amino acid, thioic acid and the like. Particularly preferred are sugar alcohols, and specific examples include maltitol and sorbit.
[0028]
In particular, as the wetting agent in the present invention, glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, In addition, by using trimethylolethane, an ink having excellent storage stability and ejection stability can be produced.
[0029]
The ratio of pigment to wetting agent has a great influence on the stability of ink ejection from the head. If the pigment solid content is high but the amount of the wetting agent is small, water evaporation near the ink meniscus of the nozzle advances and discharge failure occurs.
[0030]
The blending amount of the wetting agent is preferably 10 to 50 wt%. The ratio of the solid content of the pigment particles including the wetting agent and the dispersant is preferably 0.67 to 12.5, more preferably 1.0 to 6.0, and most preferably 2.0 to 4.0. It is a range. Ink within this range has very good drying, storage and reliability tests.
[0031]
Furthermore, by adding a penetrant to the ink, the surface tension is reduced, and the penetration into the recording medium after the ink droplets have landed on the recording medium such as paper becomes faster, thus reducing feathering and color bleeding. be able to. The appropriate surface tension range of the present invention is 35 mN / m or less. As the penetrant, an anionic surfactant or a nonionic surfactant is generally used, and a surfactant that does not impair dispersion stability is selected depending on the combination of the type of colorant, wetting agent, and water-soluble organic solvent. To do.
[0032]
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate, and the like.
Nonionic surfactants include, for example, polyols, glycol ethers, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylenes. Examples thereof include alkylamide and acetylene glycol.
As acetylene glycol surfactants, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5 An acetylene glycol type such as dimethyl-1-hexyn-3-ol (for example, Surfynol 104, 82, 465, 485 or TG from Air Products (USA)) can be used, particularly Surfynol 465, 104 and TG indicate good print quality.
The said surfactant can be used individually or in mixture of 2 or more types.
[0033]
In particular, in the present invention, the penetrant is a polyol having 8 to 11 carbon atoms, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, or the following general By using the surfactants of the formulas (2) to (7), better print quality can be obtained.
[0034]
R²-O- (CH₂CH₂O)_mCH₂COOM²                (2)
R²: Alkyl group having 6 to 14 carbon atoms which may be branched
m: integer of 3-12
M²: Alkali metal, quaternary ammonium, quaternary phosphonium, or alkanolamine
[0035]
[Chemical 1]

R^Three: A branched alkyl group having 5 to 16 carbon atoms
M^Three: Alkali metal, quaternary ammonium, quaternary phosphonium, or alkanolamine
[0036]
[Chemical 2]

R: a carbon chain having 6 to 14 carbon atoms that may be branched
k: integer of 5-20
[0037]
R^Five-(OCH₂CH₂)_lOH (5)
R^Five: Carbon chain having 6 to 14 carbon atoms that may be branched
l: integer of 5-20
[0038]
[Chemical 3]

R ′: carbon chain having 6 to 14 carbon atoms
m, n: an integer from 0 to 20
[0039]
[Formula 4]

[0040]
Conventionally known additives can be added to the ink of the present invention in addition to the colorant particles, the solvent and the dispersant.
For example, as an antiseptic / antifungal agent, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used in the present invention.
[0041]
As the pH adjuster, any substance can be used as long as the pH can be adjusted to 7 or more without adversely affecting the ink to be prepared.
Examples thereof include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, and quaternary phosphonium. Examples thereof include carbonates of alkali metals such as hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate.
[0042]
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.
[0043]
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.
[0044]
Depending on the purpose, a water-soluble ultraviolet absorber, a water-soluble infrared absorber, or the like can be added.
[0045]
An ink cartridge containing the ink composition of the present invention and an ink jet recording apparatus including the ink cartridge will be described with reference to the accompanying drawings. However, the following is only one example of the configuration, and the present invention is not limited in any way. is not.
[0046]
FIG. 1 is a schematic front view of a mechanism portion of a serial type ink jet recording apparatus equipped with an ink cartridge having a recording liquid storage portion that stores an ink composition of the present invention.
The mechanism portion of this ink jet recording apparatus lays the main support guide rod 3 and the sub support guide rod 4 between the side plates 1 and 2 on both sides in a substantially horizontal positional relationship, and the main support guide rod 3 and the sub support guide. The carriage 4 is supported by the rod 4 so as to be slidable in the main scanning direction. The carriage unit 5 has four heads 6 for ejecting yellow (Y) ink, magenta (M) ink, cyan (C) ink, and black (Bk) ink, respectively, and an ejection surface (nozzle surface) 6a. The four ink cartridges 7Y, 7M, 7C, and 7Bk are mounted on the lower side of the carriage unit 5 and are ink supply bodies of respective colors for supplying ink to the four heads 6 above the heads 6 of the carriage unit 5, respectively. Is installed in a replaceable manner.
[0047]
The carriage unit 5 is connected to a timing belt 11 stretched between a driving pulley (drive timing pulley) 9 and a driven pulley (idler pulley) 10 that are rotated by the main scanning motor 8, and the main scanning motor 8 is connected to the carriage unit 5. By controlling the driving, the carriage 5, that is, the four heads 6 are moved in the main scanning direction.
[0048]
Further, sub frames 13 and 14 are erected on the bottom plate 12 connecting the side plates 1 and 2, and a conveying roller 15 for feeding the paper 16 in the sub scanning direction orthogonal to the main scanning direction is provided between the sub frames 13 and 14. Holds freely. A sub-scanning motor 17 is disposed on the side of the sub-frame 14, and a gear 18 fixed to the rotation shaft of the sub-scanning motor 17 and the transporting roller 15 in order to transmit the rotation of the sub-scanning motor 17 to the transporting roller 15. And a gear 19 fixed to the shaft.
[0049]
Further, a reliability maintenance / recovery mechanism (hereinafter referred to as “subsystem”) 21 of the head 6 is disposed between the side plate 1 and the subframe 13. The sub-system 21 holds four cap means 22 for capping the ejection surface of each head 6 by a holder 23, and this holder 23 is held by a link member 24 so as to be swingable so that the carriage unit 5 can move in the main scanning direction. When the carriage unit 5 comes into contact with the engaging portion 25 provided on the holder 23 by the movement of the holder 23, the holder 23 is lifted up according to the movement of the carriage unit 5 and the ejection surface 6a of the inkjet head 6 is capped by the cap means 22, As the carriage unit 5 moves to the printing region side, the holder 23 is lifted down as the carriage unit 5 moves, so that the cap means 22 moves away from the ejection surface 6 a of the inkjet head 6.
[0050]
The cap means 22 is connected to the suction pump 27 via the suction tube 26, forms an atmosphere opening port, and communicates with the atmosphere via the atmosphere opening tube and the atmosphere opening valve. The suction pump 27 discharges the sucked waste liquid to a waste liquid storage tank (not shown) through a drain tube or the like.
[0051]
Further, on the side of the holder 23, a wiper blade 28, which is a wiping means made of an elastic member such as a fiber member, a foam member, or rubber, for wiping the discharge surface 6a of the inkjet head 6 is attached to a blade arm 29. Reference numeral 29 is pivotally supported so that it can be swung by rotation of a cam that is rotated by a driving means (not shown).
[0052]
Next, the ink cartridge 7 will be described with reference to FIGS. Here, FIG. 2 is an external perspective view of the ink cartridge before being loaded into the recording apparatus, and FIG. 3 is a front sectional view of the ink cartridge.
As shown in FIG. 3, the ink cartridge 7 includes an ink absorber 42 that absorbs ink of a required color in a cartridge main body 41. The cartridge body 41 is formed by adhering or welding an upper lid member 44 to an upper opening of a case 43 having a wide opening at the upper portion, and is made of, for example, a resin molded product. The ink absorber 42 is made of a porous material such as a urethane foam, and after being compressed and inserted into the cartridge body 41, the ink is absorbed.
[0053]
An ink supply port 45 for supplying ink to the recording head 6 is formed at the bottom of the case 43 of the cartridge body 41, and a seal ring 46 is fitted on the inner peripheral surface of the ink supply port 45. The upper lid member 44 has an air opening 47 formed therein.
In the cartridge main body 41, the case 43 is compressed and deformed by the pressure applied to the wide side wall when the ink supply port 45 is closed and the cartridge is handled during loading and transportation, or during vacuum packaging. In order to prevent the internal ink from leaking, a cap member 50 is attached.
[0054]
Further, as shown in FIG. 2, the air opening 47 has an oxygen permeability of 100 ml / m.²The film-like sealing member 55 described above is adhered to the upper lid member 44 for sealing. The seal member 55 is sized to seal the plurality of grooves 48 formed around the air release port 47 as well as the atmosphere. In this way, the oxygen permeability of the atmosphere opening 47 is 100 ml / m.²By sealing with the sealing member 55 described above, the ink cartridge 7 is packaged under reduced pressure using a packaging member such as a non-permeable aluminum laminate film, so that the ink absorber 42 and the cartridge main body 41 Even when the gas is dissolved in the ink due to the atmosphere in the space A (see FIG. 3) generated between the air and the packaging member outside the cartridge main body 41 having a high degree of vacuum, the air in the ink passes through the seal member 55. The ink is discharged into the space between the ink and the degree of deaeration of the ink is improved.
[0055]
FIG. 4 shows an example of the configuration of an ink cartridge provided with an ink containing portion containing the ink composition of the present invention and a head portion for ejecting ink droplets.
[0056]
That is, the recording unit 30 is of a serial type, and includes a main part including an ink jet head 6, an ink tank 41 that stores ink supplied to the ink jet head 6, and a lid member that seals the inside of the ink tank 41. Is configured. The inkjet head 6 is formed with a large number of nozzles 32 for discharging a recording liquid. The ink is guided from the ink tank 41 to a common liquid chamber (not shown) via an ink supply pipe (not shown), and is ejected from the nozzle 32 in accordance with an electrical signal from the recording apparatus main body input from the electrode 31. . This type of recording unit has a structure suitable for a head of a type that can be manufactured at low cost, a head called a thermal method or a bubble method, which uses thermal energy as a driving power source. The ink composition of the present invention is suitable not only in a recording method in which ink is ejected by applying thermal energy, but also in a recording method in which ink is ejected by applying mechanical energy.
[0057]
Here, the serial type ink jet recording apparatus as described above has been described, but the ink composition of the present invention has the same or a fraction of the density as the target image resolution in an arbitrary arrangement such as staggered nozzles. It is also possible to apply the present invention to a recording apparatus having a so-called line head, which is integrated in an array and arranged more than the width of the recording medium.
[0058]
In addition, the recording apparatus here may be an apparatus having a complex function in combination with a fax machine, a scanner, a telephone, or the like as well as an output printer for a PC or a digital camera.
[0059]
  Examples below, Reference examples, Comparative examplesThus, the present invention will be described in more detail.
referenceExample 1
<Millbase prescription>
  Silica / carbon black composite pigment (Toda Kogyo Co., Ltd., primary particle size 18 nm)
                                                            13 parts by weight
  Dialkylsulfosuccinic acid ester Na salt (anionic surfactant)
    (Adeka Coal EC-4500, Asahi Denka Kogyo Co., Ltd.) 7 parts by weight
  Ion exchange water 80 parts by weight
<Ink prescription>
  Mill base 100 parts by weight
  15 parts by weight of glycerin
  25 parts by weight of diethylene glycol
  2,2,4-Trimethyl-1,3-pentanediol 3 parts by weight
  3 parts by weight of a surfactant represented by the following formula
    C₁₃H₂₇-O- (CH₂CH₂O)_ThreeCH₂COONa
  Proxel LV (antiseptic and antifungal agent) 0.2 parts by weight
  54 parts by weight of ion exchange water
[0060]
  When a dialkylsulfosuccinate Na salt is dissolved in ion-exchanged water, and the pigment is mixed and sufficiently moistened, DYNOMILL KDL A type (manufactured by WAB) as a kneading device is filled with φ0.5 mm zirconia beads, and 3 at 2000 rpm. Time milling was performed to obtain a mill base.
  Next, glycerin, diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol, a surfactant represented by the above formula, and proxel LV are dissolved in ion-exchanged water to prepare a vehicle, which is mixed with the mill base. After filtering with a 1 μm Teflon (registered trademark) filter,For inkjetA black ink was obtained.
[0061]
referenceExample 2
<Millbase prescription>
  Silica / phthalocyanine PB15: 3 composite pigment
    (Toda Kogyo Co., Ltd., primary particle size 16 nm) 13 parts by weight
  Alkylbenzenesulfonic acid Na salt (anionic surfactant)
    (Neopelex No. 25, Kao Corporation) 7 parts by weight
  Ion exchange water 80 parts by weight
<Ink prescription>
  Mill base 100 parts by weight
  10 parts by weight of glycerin
  1,6-hexanediol 30 parts by weight
  2-ethyl-1,3-hexanediol 4 parts by weight
  2 parts by weight of surfactant represented by the following formula
    C₁₃H₂₇-(OCH₂CH₂)₈OH
  Proxel LV (antiseptic and antifungal agent) 0.2 parts by weight
  54 parts by weight of ion exchange water
  Using the above millbase formulation,referenceA mill base was prepared in the same manner as in Example 1, and then glycerin, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, a surfactant represented by the above formula, and Proxel LV were ion exchanged. A vehicle was prepared by dissolving in water, mixed with a mill base, and then filtered through a 1 μm Teflon (registered trademark) filter to obtain an inkjet cyan ink.
[0062]
Example1
<Millbase prescription>
  Silica / disazo yellow composite pigment (Toda Kogyo Co., Ltd., primary particle size 17 nm)
                                                          13 parts by weight
  3 parts by weight of an anionic surfactant represented by the following formula
    C_TenH_{twenty one}-O- (CH₂CH₂O)₁₇SO_ThreeNH_Four
  Ion exchange water 80 parts by weight
<Ink prescription>
  Mill base 100 parts by weight
  10 parts by weight of glycerin
  1,3-butanediol 30 parts by weight
  2-ethyl-1,3-hexanediol 4 parts by weight
  Acetylene-based surfactant described in the general formula (7) (p + q = 10)
    (Surfinol 465, Nissin Chemical Co., Ltd.) 4 parts by weight
  Proxel LV (antiseptic and antifungal agent) 0.2 parts by weight
  54 parts by weight of ion exchange water
  Using the above millbase formulation,referenceA mill base was prepared in the same manner as in Example 1, and then glycerin, 1,3-butanediol, 2-ethyl-1,3-hexanediol, a surfactant represented by the above general formula (7), and proxel A vehicle was prepared by dissolving LV in ion-exchanged water, mixed with a mill base, and then filtered through a 1 μm Teflon (registered trademark) filter to obtain an inkjet yellow ink.
[0063]
Reference example 3
<Millbase prescription>
  Silica / quinacridone PR122 composite pigment
    (Toda Kogyo Co., Ltd., primary particle size 16 nm) 13 parts by weight
  Polycarboxylic acid Na salt (modified product of styrene / maleic acid copolymer)
    (Anionic surfactant) (Floren TG-750, Kyoeisha Chemical Co., Ltd.)
                                                            7 parts by weight
  Ion exchange water 80 parts by weight
  Using the above millbase formulation,referenceA mill base was produced in the same manner as in Example 1,referenceAn ink jet magenta ink was obtained using the same ink formulation and method as in Example 2.
[0064]
Comparative Example 1
<Millbase prescription>
  Silica / quinacridone PR122 composite pigment
    (Toda Kogyo Co., Ltd., primary particle size 16 nm) 13 parts by weight
  Nonylphenol ethylene oxide adduct (nonionic surfactant)
                                                            7 parts by weight
  Ion exchange water 80 parts by weight
  Using the above millbase formulation,referenceA mill base was produced in the same manner as in Example 1,referenceAn ink jet magenta ink was obtained using the same ink formulation and method as in Example 2.
[0065]
Comparative Example 2
<Millbase prescription>
  Phthalocyanine PB15: 3
    (Daiichi Seika Kogyo Co., Ltd., ECB-301) 13 parts by weight
  Alkylbenzenesulfonic acid Na salt (anionic surfactant)
    (Neopelex No. 25, Kao Corporation) 7 parts by weight
  Ion exchange water 80 parts by weight
  Using the above millbase formulation,referenceA mill base was produced in the same manner as in Example 1,referenceUsing the same ink formulation and method as in Example 2, an inkjet cyan ink was obtained.
[0066]
Comparative Example 3
<Ink prescription>
  Acid Red 52 (water-soluble dye) 3 parts by weight
  5 parts by weight of glycerin
  15 parts by weight of diethylene glycol
  2-ethyl-1,3-hexanediol 1 part by weight
  Acetylene-based surfactant described in the general formula (7) (p + q = 10)
    (Surfinol 465, Nissin Chemical Co., Ltd.) 2 parts by weight
  Sodium dehydroacetate 0.2 parts by weight
  74 parts by weight of ion exchange water
  After stirring and dissolving the composition of the above ink formulation, the pH is adjusted to 10 with a 10% aqueous solution of lithium hydroxide and filtered through a 0.20 μm Teflon (registered trademark) filter.For inkjetA magenta ink was obtained.
[0067]
  Example obtainedReference examples and comparative examplesThe ink was evaluated. Evaluation items and evaluation methods are described below, and the results are shown in Table 1.
(1) Diameter measurement
  ExampleReference examplesIn addition, the volume average particle size of the colorant particles of the inkjet ink in the comparative example was measured using a microtrack UPA.
[0068]
(2) Surface tension measurement
  ExampleReference examplesAnd the surface tension of the ink for inkjet in the comparative example was measured using CBVP-Z type made from Kyowa Interface Science.
[0069]
(3) Discharge stability evaluation
  ExampleReference examplesIn addition, in the comparative example, the ink jet ink is filled in the Ricoh ink jet printer IPSiO Jet300 that discharges ink by applying mechanical energy, and the printing operation can be stopped without performing cap, cleaning, or the like. The reliability was determined according to the following evaluation criteria based on how long (seconds) the ejection direction shifted or the weight of the discharged droplets changed.
  <Evaluation criteria>
    : 600 seconds or more
    ○: 120 seconds or more and less than 600 seconds
    Δ: 30 seconds or more and less than 120 seconds
    X: Less than 30 seconds
[0070]
(4) Lightness measurement
  ExampleReference examplesAnd the ink for inkjet in the comparative example was filled in Ricoh inkjet printer IPSiO Jet300, and solid was printed by one pass. The printing test paper used was the following plain paper and glossy paper, and after printing and drying, the lightness was measured with a reflective color spectrocolorimeter (manufactured by X-Rite). Calculate the ratio of the measured brightness value to the brightness value (yellow: 87.27, magenta: 44.69, cyan: 51.36) of the standard color (Japan color ver.2) Evaluation was made according to criteria.
  <Printing test paper>
    Plain paper: My paper (NBS Ricoh Co., Ltd.)
    Glossy paper: MC glossy paper (Epson)
  <Evaluation criteria>
    A: 1.0 or more
    ○: 0.8 or more and less than 1.0
    Δ: 0.6 or more and less than 0.8
    ×: Less than 0.6
[0071]
(5)Light resistance evaluation
  Using an Atlas weatherometer Ci35AW, an xenon irradiance approximating outdoor sunlight in an environment of 70 ° C, 50% RH, and a black panel temperature of 89 ° C is used for an image sample produced by the same method as the brightness measurement.²Irradiation was performed at (340 nm) for 24 hours, and before and after fading and color change were determined according to the following evaluation criteria.
  <Evaluation criteria>
    ◎: Almost no change
    ○: Things with little change
    Δ: Change is recognized but acceptable
    ×: Fading and large color change
[0072]
[Table 1]

[0073]
  From the results of Table 1, according to the present inventionFor inkjetThe dispersed particle diameters of the colorant particles of the ink composition are all 100 nm or less. Further, by using the anionic surfactant represented by the general formula (1) or the specific polycarboxylate as a dispersant, 1 It can be seen that fine dispersion can be achieved to a state close to the next particle, and the ejection stability is high. Furthermore, while maintaining light resistance comparable to that of organic pigment ink, the color tone is as bright as dye ink.forIt can be seen that it is possible to obtain ink and recorded matter using it.
[0074]
【The invention's effect】
  Since the dispersed particles can be extremely finely stabilized by using the ink composition of the present invention, it is possible to provide an inkjet ink excellent in ejection stability, a recording method using the same, and a recorded matter. Become.
  Furthermore, by using the ink composition of the present invention, the characteristics excellent in light resistance unique to the pigment-dispersed ink are not impaired, and the color tone is comparable to that of the dye ink.For inkjetInk, a recording method using the ink, and a recorded matter can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic front view showing a configuration example of a serial type ink jet recording apparatus equipped with an ink cartridge containing an ink composition to which the present invention is applied.
FIG. 2 is an external perspective view of an ink cartridge before being loaded into a recording apparatus.
FIG. 3 is a front sectional view of the ink cartridge.
FIG. 4 is an external perspective view of an ink cartridge integrated with a recording head.
[Explanation of symbols]
1, 2 side plate
3 Main support guide rod
4 Sub-support guide rod
5 Carriage unit
6 Inkjet head
6a Discharge surface
7, 7Y, 7M, 7C, 7Bk ink cartridge
8 Main scanning motor
9 Drive pulley
10 Driven pulley
11 Timing belt
12 Bottom plate
13, 14 subframe
15 Transport roller
16 paper
17 Sub-scanning motor
18, 19 Gear
21 Subsystem
22 Cap means
23 Holder
24 Link member
25 engaging part
26 Suction tube
27 Suction pump
28 Wiper blade
29 Blade Arm
30 recording units
31 electrodes
32 nozzles
41 Cartridge body (ink tank)
42 Ink absorber
43 cases
44 Upper lid member
45 Ink supply port
46 Seal Ring
47 Opening to the atmosphere
48 grooves
50 Cap member
55 Film-like sealing member
A space

Claims (9)

At least inorganic pigment particles are coated with an organic pigment or carbon black, and contain colorant particles having a volume average particle diameter of 5 to 100 nm, a dispersant, and water. The dispersant is represented by the following general formula (1). inkjet ink composition characterized in that in an anionic surfactant represented.
R ¹ —O— (CH ₂ CH ₂ O) _j —SO ₃ M ¹ (1)
R ¹ : an alkyl group having 5 to 15 carbon atoms which may be branched j: an integer of 10 to 20 M ¹ : alkali metal, ammonium, phosphonium,
Or alkanolamine   The inkjet ink composition according to claim 1, wherein the anionic surfactant is a polycarboxylic acid salt neutralized with an alkali metal, ammonium, phosphonium, or alkanolamine.   The inkjet ink composition according to claim 1, wherein the inorganic pigment particles are composed of any one of titanium dioxide, silica, alumina, iron oxide, iron hydroxide, and tin oxide.   2. The ink jet according to claim 1, wherein the organic pigment is one of an aniline black pigment, a phthalocyanine pigment, a quinacridone pigment, a monoazo yellow pigment, a disazo yellow pigment, and a heterocyclic yellow pigment. Ink composition. The ink composition for inkjet according to any one of claims 1 to 4 , wherein the surface tension is 35 mN / m or less. A recording method for printing on a recording medium by applying ink composition, inkjet recording method using the inkjet ink composition according to any one of claims 1 to 5 as an ink composition. The inkjet recording method according to claim 6 , wherein the inkjet recording method ejects ink by applying thermal energy to the ink. The inkjet recording method according to claim 6 , wherein the inkjet recording method ejects ink by applying mechanical energy to the ink. A recorded matter recorded by the inkjet recording method according to any one of claims 6 to 8 .

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