JP4032630B2 - Toner for developing electrostatic image, method for producing the same, and image forming method - Google Patents

Description

【０１１９】
上記記載の離型剤、一般式で表される定着改良剤の添加量としては、静電荷像現像用トナー全体に１〜３０質量％、好ましくは２〜２０質量％、さらに好ましくは３〜１５質量％である。
【０１２０】
本発明の静電荷像現像用トナーを構成する樹脂成分の好ましい分子量、分子量範囲、ピーク分子量等について説明する。
【０１２１】
本発明のトナーは、ピークまたはショルダーが１００，０００〜１，０００，０００、および１，０００〜５０，０００に存在することが好ましく、さらにピークまたはショルダーが１００，０００〜１，０００，０００と、２５，０００〜１５０，０００と、１，０００〜５０，０００の範囲に存在することがさらに好ましい。
【０１２２】
トナーの樹脂の分子量は、１００，０００〜１，０００，０００の領域にピークもしくは肩（ショルダー）を有する高分子量成分と、１，０００〜５０，０００未満の領域にピークもしくは肩（ショルダー）を有する低分子量成分の両成分を少なくとも含有する樹脂が好ましい。さらに好ましくは、ピーク分子量で１５，０００〜１００，０００の部分にピークまたは肩を有する中間分子量体の樹脂を使用することである。
【０１２３】
上記の分子量の測定は、ＴＨＦ（テトラヒドロフラン）をカラム溶媒として用いるＧＰＣ（ゲルパーミエーションクロマトグラフィー）を用いて分子量測定を行う。
【０１２４】
具体的には、測定試料を１ｍｇに対してＴＨＦを１ｍｌ加え、室温下にてマグネチックスターラーを用いて撹拌を行い、充分に溶解させる。ついで、ポアサイズ０．４５〜０．５０μｍのメンブランフィルターで処理した後に、ＧＰＣへ注入する。ＧＰＣの測定条件は、４０℃にてカラムを安定化させ、ＴＨＦを毎分１ｍｌの流速で流し、１ｍｇ／ｍｌの濃度の試料を約１００μｌ注入して測定する。カラムとしては、市販のポリスチレンジェルカラムを組み合わせて使用することが好ましい。例えば、昭和電工社製のＳｈｏｄｅｘ ＧＰＣ ＫＦ−８０１、８０２、８０３、８０４、８０５、８０６、８０７の組合せや、東ソー社製のＴＳＫｇｅｌＧ１０００Ｈ、Ｇ２０００Ｈ、Ｇ３０００Ｈ、Ｇ４０００Ｈ、Ｇ５０００Ｈ、Ｇ６０００Ｈ、Ｇ７０００Ｈ、ＴＳＫ ｇｕａｒｄ ｃｏｌｕｍｎの組合せなどをあげることができる。
【０１２５】
検出器としては、屈折率検出器（ＩＲ検出器）、あるいはＵＶ検出器が好ましく用いられる。試料の分子量測定では、試料の有する分子量分布を単分散のポリスチレン標準粒子を用いて作成した検量線を用いて算出する。検量線作成用のポリスチレンとしては１０点程度用いることが好ましい。
【０１２６】
本発明の静電荷像現像用トナーの製造に係る、濾過・洗浄工程について説明する。
【０１２７】
この濾過・洗浄工程では、上記の工程で得られたトナー粒子の分散系からトナー粒子を濾別する濾過処理と、濾別されたトナー粒子（ケーキ状の集合物）から界面活性剤や凝集剤などの付着物を除去する洗浄処理とが施される。
【０１２８】
ここに、濾過処理方法としては、遠心分離法、ヌッチェ等を使用して行う減圧濾過法、フィルタープレス等を使用して行う濾過法など特に限定されるものではない。
【０１２９】
《乾燥工程》
この工程は、洗浄処理されたトナー粒子を乾燥処理する工程である。
【０１３０】
この工程で使用される乾燥機としては、スプレードライヤー、真空凍結乾燥機、減圧乾燥機などを挙げることができ、静置棚乾燥機、移動式棚乾燥機、流動層乾燥機、回転式乾燥機、攪拌式乾燥機などを使用することが好ましい。
【０１３１】
乾燥処理されたトナー粒子の水分は、５質量％以下であることが好ましく、更に好ましくは２質量％以下とされる。
【０１３２】
尚、乾燥処理されたトナー粒子同士が、弱い粒子間引力で凝集している場合には、当該凝集体を解砕処理してもよい。ここに、解砕処理装置としては、ジェットミル、ヘンシェルミキサー、コーヒーミル、フードプロセッサー等の機械式の解砕装置を使用することができる。
【０１３３】
本発明に係る重合性単量体について説明する。
（１）疎水性単量体
単量体成分を構成する疎水性単量体としては、特に限定されるものではなく従来公知の単量体を用いることができる。また、要求される特性を満たすように、１種または２種以上のものを組み合わせて用いることができる。
【０１３４】
具体的には、モノビニル芳香族系単量体、（メタ）アクリル酸エステル系単量体、ビニルエステル系単量体、ビニルエーテル系単量体、モノオレフィン系単量体、ジオレフィン系単量体、ハロゲン化オレフィン系単量体等を用いることができる。
【０１３５】
ビニル芳香族系単量体としては、例えば、スチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、ｐ−メトキシスチレン、ｐ−フェニルスチレン、ｐ−クロロスチレン、ｐ−エチルスチレン、ｐ−ｎ−ブチルスチレン、ｐ−ｔｅｒｔ−ブチルスチレン、ｐ−ｎ−ヘキシルスチレン、ｐ−ｎ−オクチルスチレン、ｐ−ｎ−ノニルスチレン、ｐ−ｎ−デシルスチレン、ｐ−ｎ−ドデシルスチレン、２，４−ジメチルスチレン、３，４−ジクロロスチレン等のスチレン系単量体およびその誘導体が挙げられる。
【０１３６】
アクリル系単量体としては、アクリル酸、メタクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、アクリル酸−２−エチルヘキシル、アクリル酸シクロヘキシル、アクリル酸フェニル、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ブチル、メタクリル酸ヘキシル、メタクリル酸−２−エチルヘキシル、β−ヒドロキシアクリル酸エチル、γ−アミノアクリル酸プロピル、メタクリル酸ステアリル、メタクリル酸ジメチルアミノエチル、メタクリル酸ジエチルアミノエチル等が挙げられる。
【０１３７】
ビニルエステル系単量体としては、酢酸ビニル、プロピオン酸ビニル、ベンゾエ酸ビニル等が挙げられる。
【０１３８】
ビニルエーテル系単量体としては、ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソブチルエーテル、ビニルフェニルエーテル等が挙げられる。
【０１３９】
モノオレフィン系単量体としては、エチレン、プロピレン、イソブチレン、１−ブテン、１−ペンテン、４−メチル−１−ペンテン等が挙げられる。
【０１４０】
ジオレフィン系単量体としては、ブタジエン、イソプレン、クロロプレン等が挙げられる。
【０１４１】
（２）架橋性単量体
樹脂粒子の特性を改良するために架橋性単量体を添加しても良い。架橋性単量体としては、ジビニルベンゼン、ジビニルナフタレン、ジビニルエーテル、ジエチレングリコールメタクリレート、エチレングリコールジメタクリレート、ポリエチレングリコールジメタクリレート、フタル酸ジアリル等の不飽和結合を２個以上有するものが挙げられる。
【０１４２】
（３）酸性極性基を有する単量体
酸性極性基を有する単量体としては、（ａ）カルボキシル基（−ＣＯＯＨ）を有するα，β−エチレン性不飽和化合物及び（ｂ）スルホン基（−ＳＯ₃Ｈ）を有するα，β−エチレン性不飽和化合物を挙げることができる。
【０１４３】
（ａ）の−ＣＯＯ基を有するα，β−エチレン性不飽和化合物の例としては、アクリル酸、メタアクリル酸、フマール酸、マレイン酸、イタコン酸、ケイ皮酸、マレイン酸モノブチルエステル、マレイン酸モノオクチルエステル、およびこれらのＮａ、Ｚｎ等の金属塩類等を挙げることができる。
【０１４４】
（ｂ）スルホ基（−ＳＯ₃Ｈ基）を有するα，β−エチレン性不飽和化合物の例としてはスルホン化スチレン、そのＮａ塩、アリルスルホコハク酸、アリルスルホコハク酸オクチル、そのＮａ塩等を挙げることができる。
【０１４５】
本発明に係る重合性単量体の重合に用いられる開始剤（重合開始剤ともいう）について説明する。
【０１４６】
本発明に用いられる重合開始剤は水溶性であれば適宜使用が可能である。例えば過硫酸塩（過硫酸カリウム、過硫酸アンモニウム等）、アゾ系化合物（４，４′−アゾビス４−シアノ吉草酸及びその塩、２，２′−アゾビス（２−アミジノプロパン）塩等）、過酸化水素、ベンゾイルパーオキサイド等のパーオキサイド化合物等が挙げられる。
【０１４７】
更に上記重合開始剤は、必要に応じて還元剤と組み合わせレドックス系開始剤とする事が可能である。レドックス系開始剤を用いる事で、重合活性が上昇し重合温度の低下が図れ、更に重合時間の短縮が期待できる。
【０１４８】
重合温度は、重合開始剤の最低ラジカル生成温度以上であればどの温度を選択しても良いが、例えば５０℃から８０℃の範囲が用いられる。又、常温開始の重合開始剤、例えば過酸化水素−還元剤（アスコルビン酸等）の組み合わせを用いる事で室温またはそれに近い温度で重合する事も可能である。
【０１４９】
本発明に用いられる連鎖移動剤について説明する。
本発明においては、重合性単量体が重合して生成する樹脂粒子の分子量を調整することを目的として、従来公知の一般的に用いられる連鎖移動剤を用いることが可能である。
【０１５０】
連鎖移動剤としては、特に限定されないが、特に、メルカプト基を有する化合物は分子量分布がシャープであるトナーが得られ、保存性、定着強度、耐オフセット性に優れるために好ましく用いられる。例えば、オクチルメルカプタン、ドデシルメルカプタン、ｔｅｒｔ−ドデシルメルカプタン等のメルカプト基を有する化合物が用いられる。
【０１５１】
また、好ましいものとしては、例えば、チオグリコール酸エチル、チオグリコール酸プロピル、チオグリコール酸ブチル、チオグリコール酸ｔ−ブチル、チオグリコール酸２−エチルヘキシル、チオグリコール酸オクチル、チオグリコール酸デシル、チオグリコール酸ドデシル、エチレングリコールのチオグリコール酸エステル、ネオペンチルグリコールのチオグリコール酸エステル、ペンタエリスリトールのチオグリコール酸エステル等を挙げることが出来る。
【０１５２】
中でも、トナー加熱定着時の臭気を抑制する観点から、ｎ−オクチル−３−メルカプトプロピオン酸エステルが好ましく用いられる。
【０１５３】
本発明に係る着色剤について説明する。
本発明の静電荷像現像用トナーに係る着色剤は、トナーの帯電の均一性向上の観点から、トナー製造時、上記記載の複合樹脂粒子の塩析、凝集、融着時に樹脂粒子と共に塩析、凝集、融着され、トナー粒子中に含有されることが好ましい。
【０１５４】
本発明のトナーを構成する着色剤（複合樹脂粒子との塩析、凝集、融着に供される着色剤粒子）としては、各種の無機顔料、有機顔料、染料を挙げることができる。無機顔料としては、従来公知のものを用いることができる。具体的な無機顔料を以下に例示する。
【０１５５】
黒色の顔料としては、例えば、ファーネスブラック、チャンネルブラック、アセチレンブラック、サーマルブラック、ランプブラック等のカーボンブラック、更にマグネタイト、フェライト等の磁性粉も用いられる。
【０１５６】
これらの無機顔料は所望に応じて単独または複数を選択併用する事が可能である。また顔料の添加量は重合体に対して２〜２０質量％であり、好ましくは３〜１５質量％が選択される。
【０１５７】
磁性トナーとして使用する際には、前述のマグネタイトを添加することができる。この場合には所定の磁気特性を付与する観点から、トナー中に２０〜１２０質量％添加することが好ましい。
【０１５８】
有機顔料及び染料としても従来公知のものを用いることができる。具体的な有機顔料及び染料を以下に例示する。
【０１５９】
マゼンタまたはレッド用の顔料としては、Ｃ．Ｉ．ピグメントレッド２、Ｃ．Ｉ．ピグメントレッド３、Ｃ．Ｉ．ピグメントレッド５、Ｃ．Ｉ．ピグメントレッド６、Ｃ．Ｉ．ピグメントレッド７、Ｃ．Ｉ．ピグメントレッド１５、Ｃ．Ｉ．ピグメントレッド１６、Ｃ．Ｉ．ピグメントレッド４８：１、Ｃ．Ｉ．ピグメントレッド５３：１、Ｃ．Ｉ．ピグメントレッド５７：１、Ｃ．Ｉ．ピグメントレッド１２２、Ｃ．Ｉ．ピグメントレッド１２３、Ｃ．Ｉ．ピグメントレッド１３９、Ｃ．Ｉ．ピグメントレッド１４４、Ｃ．Ｉ．ピグメントレッド１４９、Ｃ．Ｉ．ピグメントレッド１６６、Ｃ．Ｉ．ピグメントレッド１７７、Ｃ．Ｉ．ピグメントレッド１７８、Ｃ．Ｉ．ピグメントレッド２２２等が挙げられる。
【０１６０】
オレンジまたはイエロー用の顔料としては、Ｃ．Ｉ．ピグメントオレンジ３１、Ｃ．Ｉ．ピグメントオレンジ４３、Ｃ．Ｉ．ピグメントイエロー１２、Ｃ．Ｉ．ピグメントイエロー１３、Ｃ．Ｉ．ピグメントイエロー１４、Ｃ．Ｉ．ピグメントイエロー１５、Ｃ．Ｉ．ピグメントイエロー１７、Ｃ．Ｉ．ピグメントイエロー９３、Ｃ．Ｉ．ピグメントイエロー９４、Ｃ．Ｉ．ピグメントイエロー１３８、Ｃ．Ｉ．ピグメントイエロー１８０、Ｃ．Ｉ．ピグメントイエロー１８５、Ｃ．Ｉ．ピグメントイエロー１５５、Ｃ．Ｉ．ピグメントイエロー１５６等が挙げられる。
【０１６１】
グリーンまたはシアン用の顔料としては、Ｃ．Ｉ．ピグメントブルー１５、Ｃ．Ｉ．ピグメントブルー１５：２、Ｃ．Ｉ．ピグメントブルー１５：３、Ｃ．Ｉ．ピグメントブルー１６、Ｃ．Ｉ．ピグメントブルー６０、Ｃ．Ｉ．ピグメントグリーン７等が挙げられる。
【０１６２】
また、染料としてはＣ．Ｉ．ソルベントレッド１、同４９、同５２、同５８、同６３、同１１１、同１２２、Ｃ．Ｉ．ソルベントイエロー１９、同４４、同７７、同７９、同８１、同８２、同９３、同９８、同１０３、同１０４、同１１２、同１６２、Ｃ．Ｉ．ソルベントブルー２５、同３６、同６０、同７０、同９３、同９５等を用いる事ができ、またこれらの混合物も用いる事ができる。
【０１６３】
これらの有機顔料及び染料は所望に応じて単独または複数を選択併用する事が可能である。また顔料の添加量は重合体に対して２〜２０質量％であり、好ましくは３〜１５質量％が選択される。
【０１６４】
本発明の静電荷像現像用トナーを構成する着色剤（着色剤粒子）は、表面改質されていてもよい。ここに、表面改質剤としては、従来公知のものを使用することができ、具体的にはシランカップリング剤、チタンカップリング剤、アルミニウムカップリング剤等を好ましく用いることができる。
【０１６５】
シランカップリング剤としては、メチルトリメトキシシラン、フェニルトリメトキシシラン、メチルフェニルジメトキシシラン、ジフェニルジメトキシシラン等のアルコキシシラン、ヘキサメチルジシロキサン等のシロキサン、γ−クロロプロピルトリメトキシシラン、ビニルトリクロロシラン、ビニルトリメトキシシラン、ビニルトリエトキシシラン、γ−メタクリロキシプロピルトリメトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−メルカプトプロピルトリメトキシシラン、γ−アミノプロピルトリエトキシシラン、γ−ウレイドプロピルトリエトキシシラン等が挙げられる。
【０１６６】
チタンカップリング剤としては、例えば、味の素社製の「プレンアクト」と称する商品名で市販されているＴＴＳ、９Ｓ、３８Ｓ、４１Ｂ、４６Ｂ、５５、１３８Ｓ、２３８Ｓ等、日本曹達社製の市販品Ａ−１、Ｂ−１、ＴＯＴ、ＴＳＴ、ＴＡＡ、ＴＡＴ、ＴＬＡ、ＴＯＧ、ＴＢＳＴＡ、Ａ−１０、ＴＢＴ、Ｂ−２、Ｂ−４、Ｂ−７、Ｂ−１０、ＴＢＳＴＡ−４００、ＴＴＳ、ＴＯＡ−３０、ＴＳＤＭＡ、ＴＴＡＢ、ＴＴＯＰ等が挙げられる。
【０１６７】
アルミニウムカップリング剤としては、例えば、味の素社製の「プレンアクトＡＬ−Ｍ」等が挙げられる。
【０１６８】
これらの表面改質剤の添加量は、着色剤に対して０．０１〜２０質量％であることが好ましく、更に好ましくは０．１〜５質量％とされる。
【０１６９】
着色剤粒子の表面改質法としては、着色剤粒子の分散液中に表面改質剤を添加し、この系を加熱して反応させる方法を挙げることができる。
【０１７０】
表面改質された着色剤粒子は、濾過により採取され、同一の溶媒による洗浄処理と濾過処理が繰り返された後、乾燥処理される。
【０１７１】
本発明のトナーを構成するトナー粒子には、荷電制御剤など、離型剤以外の内添剤が含有されていてもよい。
【０１７２】
トナー粒子中に含有される荷電制御剤としては、ニグロシン系染料、ナフテン酸または高級脂肪酸の金属塩、アルコキシル化アミン、第４級アンモニウム塩化合物、アゾ系金属錯体、サリチル酸金属塩またはその金属錯体等が挙げられる。
【０１７３】
本発明のトナーに用いられる外添剤について説明する。
外添剤として使用できる無機微粒子としては、従来公知のものを挙げることができる。具体的には、シリカ微粒子、チタン微粒子、アルミナ微粒子等を好ましく用いることができる。これら無機微粒子は疎水性であることが好ましい。
【０１７４】
シリカ微粒子の具体例としては、日本アエロジル（株）製の市販品Ｒ−８０５、Ｒ−９７６、Ｒ−９７４、Ｒ−９７２、Ｒ−８１２、Ｒ−８０９、ヘキスト（株）製のＨＶＫ−２１５０、Ｈ−２００、キャボット（株）製の市販品ＴＳ−７２０、ＴＳ−５３０、ＴＳ−６１０、Ｈ−５、ＭＳ−５等が挙げられる。
【０１７５】
チタン微粒子の具体例としては、例えば、日本アエロジル（株）製の市販品Ｔ−８０５、Ｔ−６０４、テイカ（株）製の市販品ＭＴ−１００Ｓ、ＭＴ−１００Ｂ、ＭＴ−５００ＢＳ、ＭＴ−６００、ＭＴ−６００ＳＳ、ＪＡ−１、富士チタン（株）製の市販品ＴＡ−３００ＳＩ、ＴＡ−５００、ＴＡＦ−１３０、ＴＡＦ−５１０、ＴＡＦ−５１０Ｔ、出光興産（株）製の市販品ＩＴ−Ｓ、ＩＴ−ＯＡ、ＩＴ−ＯＢ、ＩＴ−ＯＣ等が挙げられる。
【０１７６】
アルミナ微粒子の具体例としては、例えば、日本アエロジル（株）製の市販品ＲＦＹ−Ｃ、Ｃ−６０４、石原産業（株）製の市販品ＴＴＯ−５５等が挙げられる。
【０１７７】
外添剤として使用できる有機微粒子としては、数平均一次粒子径が１０〜２０００ｎｍ程度の球形の微粒子を挙げることができる。かかる有機微粒子の構成材料としては、ポリスチレン、ポリメチルメタクリレート、スチレン−メチルメタクリレート共重合体などのを挙げることができる。
【０１７８】
外添剤として使用できる滑剤としては、高級脂肪酸の金属塩を挙げることができる。かかる高級脂肪酸の金属塩の具体例としては、ステアリン酸亜鉛、ステアリン酸アルミニウム、ステアリン酸銅、ステアリン酸マグネシウム、ステアリン酸カルシウム等のステアリン酸金属塩；オレイン酸亜鉛、オレイン酸マンガン、オレイン酸鉄、オレイン酸銅、オレイン酸マグネシウム等のオレイン酸金属塩；パルミチン酸亜鉛、パルミチン酸銅、パルミチン酸マグネシウム、パルミチン酸カルシウム等のパルミチン酸金属塩；リノール酸亜鉛、リノール酸カルシウム等のリノール酸金属塩；リシノール酸亜鉛、リシノール酸カルシウムなどのリシノール酸金属塩等が挙げられる。
【０１７９】
外添剤の添加量としては、トナーに対して０．１〜５質量％程度であることが好ましい。
【０１８０】
外添剤の添加工程に着いて説明する。
この工程は、乾燥処理されたトナー粒子に外添剤を添加する工程である。
【０１８１】
外添剤を添加するために使用される装置としては、タービュラーミキサー、ヘンシエルミキサー、ナウターミキサー、Ｖ型混合機などの種々の公知の混合装置を挙げることができる。
【０１８２】
本発明の静電荷像現像用トナーの粒径について説明する。
本発明のトナーの粒径は、個数平均粒径で３〜１０μｍであることが好ましく、更に好ましくは３〜８μｍとされる。この粒径は、後に詳述するトナーの製造方法において、凝集剤の濃度や有機溶媒の添加量、融着時間、重合体の組成によって制御することができる。
【０１８３】
個数平均粒径が３〜１０μｍであることにより、定着工程において、飛翔して加熱部材に付着しオフセットを発生させる付着力の大きいトナー微粒子が少なくなり、また、転写効率が高くなってハーフトーンの画質が向上し、細線やドット等の画質が向上する。
【０１８４】
トナーの個数平均粒径は、コールターカウンターＴＡ−II、コールターマルチサイザー、ＳＬＡＤ１１００（島津製作所社製レーザー回折式粒径測定装置）等を用いて測定することができる。
【０１８５】
本発明においては、コールターマルチサイザーを用い、粒度分布を出力するインターフェース（日科機製）、パーソナルコンピューターを接続して使用した。前記コールターマルチサイザーにおけるアパーチャーとしては１００μｍのものを用いて、２μｍ以上（例えば２〜４０μｍ）のトナーの体積分布を測定して粒度分布および平均粒径を算出した。
【０１８６】
本発明のトナー粒子の形状係数について説明する。
本発明のトナーの形状係数は、下記式により示されるものであり、トナー粒子の丸さの度合いを示す。
【０１８７】
形状係数＝（（最大径／２）²×π）／投影面積
ここに、最大径とは、トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。また、投影面積とは、トナー粒子の平面上への投影像の面積をいう。
【０１８８】
本発明では、この形状係数は、走査型電子顕微鏡により２０００倍にトナー粒子を拡大した写真を撮影し、ついでこの写真に基づいて「ＳＣＡＮＮＩＮＧ ＩＭＡＧＥ ＡＮＡＬＹＺＥＲ」（日本電子社製）を使用して写真画像の解析を行うことにより測定した。この際、１００個のトナー粒子を使用して本発明の形状係数を上記算出式にて測定したものである。
【０１８９】
前記構成の（１）および（９）においては、この形状係数が１．０〜１．６の範囲にあるトナー粒子が６５個数％以上とすることが好ましく、より好ましくは、７０個数％以上である。さらに好ましくは、この形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上とすることであり、より好ましくは、７０個数％以上である。
【０１９０】
この形状係数が１．０〜１．６の範囲にあるトナー粒子が６５個数％以上であることにより、現像剤搬送部材などでの摩擦帯電性がより均一となり、過度に帯電したトナーの蓄積が無く、現像剤搬送部材表面よりトナーがより交換しやすくなるために、現像ゴースト等の問題も発生しにくくなる。さらに、トナー粒子が破砕しにくくなって帯電付与部材の汚染が減少し、トナーの帯電性が安定する。
【０１９１】
また、前記構成の（１６）においては、この形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上とすることが必要であり、好ましくは、７０個数％以上である。
【０１９２】
この形状係数を制御する方法は特に限定されるものではない。例えばトナー粒子を熱気流中に噴霧する方法、またはトナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、あるいはトナーを溶解しない溶媒中に添加し旋回流を付与する方法等により、形状係数を１．０〜１．６、または１．２〜１．６にしたトナーを調製し、これを通常のトナー中へ本発明の範囲内になるように添加して調整する方法がある。また、いわゆる重合法トナーを調整する段階で全体の形状を制御し、形状係数を１．０〜１．６、または１．２〜１．６に調整したトナーを同様に通常のトナーへ添加して調整する方法がある。
【０１９３】
本発明のトナーとしては、トナー粒子の粒径をＤ（μｍ）とするとき、自然対数ｌｎＤを横軸にとり、この横軸を０．２３間隔で複数の階級に分けた個数基準の粒度分布を示すヒストグラムにおいて、最頻階級に含まれるトナー粒子の相対度数（ｍ１）と、前記最頻階級の次に頻度の高い階級に含まれるトナー粒子の相対度数（ｍ２）との和（Ｍ）が７０％以上であるトナーであることが好ましい。
【０１９４】
相対度数（ｍ１）と相対度数（ｍ２）との和（Ｍ）が７０％以上であることにより、トナー粒子の粒度分布の分散が狭くなるので、当該トナーを画像形成工程に用いることにより選択現像の発生を確実に抑制することができる。
【０１９５】
本発明において、前記の個数基準の粒度分布を示すヒストグラムは、自然対数ｌｎＤ（Ｄ：個々のトナー粒子の粒径）を０．２３間隔で複数の階級（０〜０．２３：０．２３〜０．４６：０．４６〜０．６９：０．６９〜０．９２：０．９２〜１．１５：１．１５〜１．３８：１．３８〜１．６１：１．６１〜１．８４：１．８４〜２．０７：２．０７〜２．３０：２．３０〜２．５３：２．５３〜２．７６・・・）に分けた個数基準の粒度分布を示すヒストグラムであり、このヒストグラムは、下記の条件に従って、コールターマルチサイザーにより測定されたサンプルの粒径データを、Ｉ／Ｏユニットを介してコンピュータに転送し、当該コンピュータにおいて、粒度分布分析プログラムにより作成されたものである。
【０１９６】
《測定条件》
（１）アパーチャー：１００μｍ
（２）サンプル調製法：電解液〔ＩＳＯＴＯＮ Ｒ−１１（コールターサイエンティフィックジャパン社製）〕５０〜１００ｍｌに界面活性剤（中性洗剤）を適量加えて攪拌し、これに測定試料１０〜２０ｍｇを加える。この系を超音波分散機にて１分間分散処理することにより調製する。
【０１９７】
本発明に係る『角のないトナー粒子』について図１を用いて説明する。
本発明に係るトナーにおいては、トナーを構成するトナー粒子中、角がないトナー粒子の割合は５０個数％以上であることが好ましく、更に好ましくは、７０個数％以上である。
【０１９８】
角がないトナー粒子の割合が５０個数％以上であることにより、転写されたトナー層（粉体層）の空隙が減少して定着性が向上し、オフセットが発生しにくくなる。また、摩耗、破断しやすいトナー粒子および電荷の集中する部分を有するトナー粒子が減少することとなり、帯電量分布がシャープとなって、帯電性も安定し、良好な画質を長期にわたって形成できる。
【０１９９】
ここに、「角がないトナー粒子」とは、電荷の集中するような突部またはストレスにより摩耗しやすいような突部を実質的に有しないトナー粒子を言い、具体的には以下のトナー粒子を角がないトナー粒子という。すなわち、図１（ａ）に示すように、トナー粒子Ｔの長径をＬとするときに、半径（Ｌ／１０）の円Ｃで、トナー粒子Ｔの周囲線に対し１点で内側に接しつつ内側をころがした場合に、当該円ＣがトナーＴの外側に実質的にはみださない場合を「角がないトナー粒子」という。「実質的にはみ出さない場合」とは、はみ出す円が存在する突起が１箇所以下である場合をいう。また、「トナー粒子の長径」とは、当該トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。なお、図１（ｂ）および（ｃ）は、それぞれ角のあるトナー粒子の投影像を示している。
【０２００】
角がないトナー粒子の割合の測定は次のようにして行った。先ず、走査型電子顕微鏡によりトナー粒子を拡大した写真を撮影し、さらに拡大して１５，０００倍の写真像を得る。次いでこの写真像について前記の角の有無を測定する。この測定を１００個のトナー粒子について行った。
【０２０１】
角がないトナーを得る方法は特に限定されるものではない。例えば、形状係数を制御する方法として前述したように、トナー粒子を熱気流中に噴霧する方法、またはトナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、あるいはトナーを溶解しない溶媒中に添加し、旋回流を付与することによって得ることができる。
【０２０２】
本発明に用いられる現像剤について説明する。
本発明のトナーは、一成分現像剤でも二成分現像剤として用いてもよい。
【０２０３】
一成分現像剤として用いる場合は、非磁性一成分現像剤、あるいはトナー中に０．１〜０．５μｍ程度の磁性粒子を含有させ磁性一成分現像剤としたものがあげられ、いずれも使用することができる。
【０２０４】
また、キャリアと混合して二成分現像剤として用いることができる。この場合は、キャリアの磁性粒子として、鉄、フェライト、マグネタイト等の金属、それらの金属とアルミニウム、鉛等の金属との合金等の従来から公知の材料を用いることが出来る。特にフェライト粒子が好ましい。上記磁性粒子は、その体積平均粒径としては１５〜１００μｍ、より好ましくは２５〜８０μｍのものがよい。
【０２０５】
キャリアの体積平均粒径の測定は、代表的には湿式分散機を備えたレーザ回折式粒度分布測定装置「ヘロス（ＨＥＬＯＳ）」（シンパティック（ＳＹＭＰＡＴＥＣ）社製）により測定することができる。
【０２０６】
キャリアは、磁性粒子が更に樹脂により被覆されているもの、あるいは樹脂中に磁性粒子を分散させたいわゆる樹脂分散型キャリアが好ましい。コーティング用の樹脂組成としては、特に限定は無いが、例えば、オレフィン系樹脂、スチレン系樹脂、スチレン−アクリル系樹脂、シリコーン系樹脂、エステル系樹脂或いはフッ素含有重合体系樹脂等が用いられる。また、樹脂分散型キャリアを構成するための樹脂としては、特に限定されず公知のものを使用することができ、例えば、スチレン−アクリル系樹脂、ポリエステル樹脂、フッ素系樹脂、フェノール樹脂等を使用することができる。
【０２０７】
本発明の画像形成方法について説明する。
本発明のトナーは、トナー像が形成された画像形成支持体を、定着装置を構成する加熱ローラーと加圧ローラーとの間に通過させて定着する工程を含む画像形成方法（本発明の画像形成方法）に好適に使用される。
【０２０８】
図２は、本発明の画像形成方法において使用する定着装置の一例を示す断面図であり、図２に示す定着装置は、加熱ローラー１０と、これに当接する加圧ローラー２０とを備えている。なお、図２において、Ｔは転写紙（画像形成支持体）上に形成されたトナー像である。
【０２０９】
加熱ローラー１０は、フッ素樹脂または弾性体からなる被覆層１２が芯金１１の表面に形成されてなり、線状ヒーターよりなる加熱部材１３を内包している。
【０２１０】
芯金１１は、金属から構成され、その内径は１０〜７０ｍｍとされる。芯金１１を構成する金属としては特に限定されるものではないが、例えば鉄、アルミニウム、銅等の金属あるいはこれらの合金を挙げることができる。
【０２１１】
芯金１１の肉厚は０．１〜１５ｍｍとされ、省エネルギーの要請（薄肉化）と、強度（構成材料に依存）とのバランスを考慮して決定される。例えば、０．５７ｍｍの鉄よりなる芯金と同等の強度を、アルミニウムよりなる芯金で保持するためには、その肉厚を０．８ｍｍとする必要がある。
【０２１２】
被覆層１２を構成するフッ素樹脂としては、ＰＴＦＥ（ポリテトラフルオロエチレン）およびＰＦＡ（テトラフルオロエチレン−パーフルオロアルキルビニルエーテル共重合体）などを例示することができる。
【０２１３】
フッ素樹脂からなる被覆層１２の厚みは１０〜５００μｍとされ、好ましくは２０〜４００μｍとされる。
【０２１４】
フッ素樹脂からなる被覆層１２の厚みが１０μｍ未満であると、被覆層としての機能を十分に発揮することができず、定着装置としての耐久性を確保することができない。一方、５００μｍを超える被覆層の表面には紙粉によるキズがつきやすく、当該キズ部にトナーなどが付着し、これに起因する画像汚れを発生する問題がある。
【０２１５】
また、被覆層１２を構成する弾性体としては、ＬＴＶ、ＲＴＶ、ＨＴＶなどの耐熱性の良好なシリコーンゴムおよびシリコーンスポンジゴムなどを用いることが好ましい。
【０２１６】
被覆層１２を構成する弾性体のアスカーＣ硬度は、８０°未満とされ、好ましくは６０°未満とされる。
【０２１７】
また、弾性体からなる被覆層１２の厚みは０．１〜３０ｍｍとされ、好ましくは０．１〜２０ｍｍとされる。
【０２１８】
被覆層１２を構成する弾性体のアスカーＣ硬度が８０°を超える場合、および当該被覆層１２の厚みが０．１ｍｍ未満である場合には、定着のニップを大きくすることができず、ソフト定着の効果（例えば、平滑化された界面のトナー層による色再現性の向上効果）を発揮することができない。
【０２１９】
加熱部材１３としては、ハロゲンヒーターを好適に使用することができる。
加圧ローラー２０は、弾性体からなる被覆層２２が芯金２１の表面に形成されてなる。被覆層２２を構成する弾性体としては特に限定されるものではなく、ウレタンゴム、シリコーンゴムなどの各種軟質ゴムおよびスポンジゴムを挙げることができ、被覆層１２を構成するものとして例示したシリコーンゴムおよびシリコーンスポンジゴムを用いることが好ましい。
【０２２０】
被覆層２２を構成する弾性体のアスカーＣ硬度は、８０°未満とされ、好ましくは７０°未満、更に好ましくは６０°未満とされる。
【０２２１】
また、被覆層２２の厚みは０．１〜３０ｍｍとされ、好ましくは０．１〜２０ｍｍとされる。
【０２２２】
被覆層２２を構成する弾性体のアスカーＣ硬度が８０°を超える場合、および被覆層２２の厚みが０．１ｍｍ未満である場合には、定着のニップを大きくすることができず、ソフト定着の効果を発揮することができない。
【０２２３】
芯金２１を構成する材料としては特に限定されるものではないが、アルミニウム、鉄、銅などの金属またはそれらの合金を挙げることができる。
【０２２４】
加熱ローラー１０と加圧ローラー２０との当接荷重（総荷重）としては、通常４０〜３５０Ｎとされ、好ましくは５０〜３００Ｎ、さらに好ましくは５０〜２５０Ｎとされる。この当接荷重は、加熱ローラー１０の強度（芯金１１の肉厚）を考慮して規定され、例えば０．３ｍｍの鉄よりなる芯金を有する加熱ローラーにあっては、２５０Ｎ以下とすることが好ましい。
【０２２５】
また、耐オフセット性および定着性の観点から、ニップ幅としては４〜１０ｍｍであることが好ましく、当該ニップの面圧は０．６×１０５Ｐａ〜１．５×１０５Ｐａであることが好ましい。
【０２２６】
図２に示した定着装置による定着条件の一例を示せば、定着温度（加熱ローラー１０の表面温度）が１５０〜２１０℃とされ、定着線速が８０〜６４０ｍｍ／ｓｅｃとされる。
【０２２７】
本発明において使用する定着装置には、必要に応じてクリーニング機構を付与してもよい。この場合には、シリコーンオイルを定着部の上ローラー（加熱ローラー）に供給する方式として、シリコーンオイルを含浸したパッド、ローラー、ウェッブ等で供給し、クリーニングする方法が使用できる。
【０２２８】
シリコーンオイルとしては耐熱性の高いものが使用され、ポリジメチルシリコーン、ポリフェニルメチルシリコーン、ポリジフェニルシリコーン等が使用される。粘度の低いものは使用時に流出量が大きくなることから、２０℃における粘度が１〜１００Ｐａ・ｓのものが好適に使用される。
【０２２９】
但し、本発明による効果は、シリコーンオイルを供給しない、または、シリコーンオイルの供給量がきわめて低い定着装置により、画像を形成する工程を含む場合に特に顕著に発揮される。従って、シリコーンオイルを供給する場合であっても、その供給量は２ｍｇ／Ａ４以下とすることが好ましい。
【０２３０】
シリコーンオイルの供給量を２ｍｇ／Ａ４以下とすることにより、定着後の転写紙（画像支持体）に対するシリコーンオイルの付着量が少なくなり、転写紙へ付着したシリコーンオイルによるボールペン等の油性ペンの記入しずらさがなく、加筆性が損なわれることはない。
【０２３１】
また、シリコーンオイルの変質による耐オフセット性の経時的な低下、シリコーンオイルによる光学系や帯電極の汚染などの問題を回避することができる。
【０２３２】
ここに、シリコーンオイルの供給量は、所定温度に加熱した定着装置（ローラー間）に転写紙（Ａ４サイズの白紙）を連続して１００枚通過させ、通紙前後における定着装置の質量変化（Δｗ）を測定して算出される（Δｗ／１００）。
【０２３３】
【実施例】
以下、実施例にて本発明を詳細に説明するが本発明はこれらに限定されない。
【０２３４】
《ラテックスの調製》
（ラテックス１ＨＭＬの調製）
（１）ラテックス（１Ｈ）の調製（核粒子の形成；第１段重合）
攪拌装置、温度センサー、冷却管、窒素導入装置を取り付けた５０００ｍｌのセパラブルフラスコに、７．０８ｇの化合物（１０１）をイオン交換水３０１０ｇに溶解させた界面活性剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの攪拌速度で攪拌しながら、内温を８０℃に昇温させた。
【０２３５】
この界面活性剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）９．２ｇをイオン交換水２００ｇに溶解させた開始剤溶液を添加し、温度を７５℃とした後、７０．１ｇのスチレン、１９．９ｇのｎ−ブチルアクリレート、１０．９ｇのメタクリル酸からなる単量体混合液Ａを１時間かけて滴下し、７５℃にて２時間にわたり加熱、攪拌することにより重合（第１段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これをラテックス（１Ｈ）とする。
【０２３６】
（２）ラテックス（１ＨＭ）の調製（中間層の形成：第二段重合）
攪拌装置を取り付けたフラスコ内において、１０５．６ｇのスチレン、３０．０ｇのｎ−ブチルアクリレート、６．４ｇのメタクリル酸、５．６ｇのｎ−オクチル−３−メルカプトプロピオン酸エステルからなる単量体混合液に、７２．０ｇのエステル化合物（１９）を添加し、８０℃に加温し溶解させて単量体溶液Ｂを調製した。
【０２３７】
一方、１．６ｇの化合物（１０１）を２７００ｍｌのイオン交換水に溶解させた界面活性剤溶液を８０℃に加熱し、この界面活性剤溶液に、上記のラテックス（１Ｈ）を固形分換算で２８ｇ添加した後、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック（株）製）により、単量体溶液Ｂを混合分散させ、均一な分散粒子径（２８４ｎｍ）を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０２３８】
次いで、この分散液（乳化液）に、５．１ｇの重合開始剤（ＫＰＳ：過硫酸カリウム）を２４０ｍｌのイオン交換水に溶解させた開始剤溶液と、７５０ｍｌのイオン交換水とを添加し、この系を８０℃にて３時間にわたり加熱攪拌することにより重合（第二段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の表面が中間分子量樹脂により被覆された構造の複合樹脂粒子の分散液）を得た。これを、ラテックス（１ＨＭ）とする。
【０２３９】
（３）ラテックス（１ＨＭＬ）の調製（外層の形成：第三段重合）
上記で得られたラテックス（１ＨＭ）に、７．４ｇの重合開始剤（ＫＰＳ：過硫酸カリウム）を２００ｍｌのイオン交換水に溶解させた開始剤溶液を添加し、８０℃の温度条件下に、３００ｇのスチレン、９５ｇのｎ−ブチルアクリレート、１５．３ｇのメタクリル酸、１０．４ｇのｎ−オクチル−３−メルカプトプロピオン酸エステルからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱攪拌することにより重合（第三段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有し、前記中間層にエステル化合物（１９）が含有されている複合樹脂粒子の分散液）を得た。これをラテックス（１ＨＭＬ）とする。
【０２４０】
ラテックス（１ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１３，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の重量平均粒径は１２２ｎｍであった。
【０２４１】
（ラテックス２ＨＭＬの調製）
上記のラテックス１ＨＭＬの調製において、化合物（１０１）に代えて、７．０８ｇのドデシルスルフォン酸ナトリウム（ＳＤＳ）を使用した以外は同様にして、ラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有する複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（２ＨＭＬ）」とする。
【０２４２】
ラテックス（２ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１２，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の重量平均粒径は１１０ｎｍであった。
【０２４３】
《トナーの製造例》
（トナー粒子１の作製）
５９．０ｇの化合物（１０１）を１６００ｍｌのイオン交換水に攪拌溶解した。この溶液を攪拌しながら、カーボンブラック「リーガル３３０」（キャボット社製）４２０．０ｇを徐々に添加し、次いで、「クレアミックス」（エム・テクニック（株）製）を用いて分散処理することにより、着色剤粒子の分散液１（以下、「着色剤分散液１」という）を調製した。
【０２４４】
この着色剤分散液１における着色剤粒子の粒子径を、電気泳動光散乱光度計「ＥＬＳ−８００」（大塚電子社製）を用いて測定したところ、重量平均粒子径で９８ｎｍであった。
【０２４５】
４２０．７ｇ（固形分換算）のラテックス１ＨＭＬと、９００ｇのイオン交換水と、１６６ｇの着色剤分散液１とを、温度センサー、冷却管、窒素導入装置、攪拌装置を取り付けた反応容器（四つ口フラスコ）に入れ攪拌した。内温を３０℃に調整した後、この溶液に５Ｎの水酸化ナトリウム水溶液を加えてｐＨを１１．０に調整した。
【０２４６】
次いで、塩化マグネシウム６水和物１２．１ｇをイオン交換水１０００ｍｌに溶解した水溶液を、攪拌下、３０℃にて１０分間かけて添加した。３分間放置した後に昇温を開始し、この系を６分間かけて９０℃まで昇温した（昇温速度＝１０℃／分）。その状態で、「コールターカウンターＴＡ−II」にて会合粒子の粒径を測定し、個数平均粒径が５．５μｍになった時点で、塩化ナトリウム８０．４ｇをイオン交換水１０００ｍｌに溶解した水溶液を添加して粒子成長を停止させ、さらに、熟成処理として液温度８５℃にて２時間にわたり加熱攪拌することにより融着を継続させた。その後、８℃／分の条件で４０℃まで冷却し、塩酸を添加してｐＨを２．０に調整し、攪拌を停止した。生成した会合粒子を濾過し、４５℃に温度調整したイオン交換水で繰り返し洗浄し、その後、４０℃の温風で乾燥することにより、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「トナー粒子１」とする。「トナー粒子１」の界面活性剤残留量は２８ｐｐｍ、凝集剤から導入された残留マグネシウム量は４５００ｐｐｍであった。
【０２４７】
（トナー粒子２の作製）
化合物（１０１）の代わりに前記の化合物（１０２）５９．０ｇを使用した以外はトナー粒子１の製造と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「トナー粒子２」とする。「トナー粒子２」の界面活性剤残留量は３２ｐｐｍ、凝集剤から導入された残留マグネシウム量は３６００ｐｐｍであった。
【０２４８】
（トナー粒子３の作製）
化合物（１０１）の代わりに前記の化合物（１０３）を５９．０ｇ使用した以外はトナー粒子２の作製と同様にして、個数平均粒径５．８μｍの着色粒子を得た。得られた着色粒子を「トナー粒子３」とする。「トナー粒子３」の界面活性剤残留量は４８ｐｐｍ、凝集剤から導入された残留マグネシウム量は８８７０ｐｐｍであった。
【０２４９】
（トナー粒子４の作製）
化合物（１０１）の代わりに前記の化合物（１０４）を５９．０ｇ使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．８μｍの着色粒子を得た。得られた着色粒子を「トナー粒子４」とする。「トナー粒子４」の界面活性剤残留量は５３ｐｐｍ、凝集剤から導入された残留マグネシウム量は７９６０ｐｐｍであった。
【０２５０】
（トナー粒子５の作製）
化合物（１０１）の代わりに前記の化合物（１０５）を５９．０ｇ使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．８μｍの着色粒子を得た。得られた着色粒子を「トナー粒子５」とする。「トナー粒子５」の界面活性剤残留量は８４ｐｐｍ、凝集剤から導入された残留マグネシウム量は５０５０ｐｐｍであった。
【０２５１】
（トナー粒子６の作製）
化合物（１０１）の代わりに前記の化合物（１０６）を５９．０ｇ使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「トナー粒子６」とする。「トナー粒子６」の界面活性剤残留量は９１ｐｐｍ、凝集剤から導入された残留マグネシウム量は５０５０ｐｐｍであった。
【０２５２】
（トナー粒子７の作製）
塩化マグネシウム６水和物１２．１ｇの代わりに塩化カルシウム１８．２ｇを使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．８μｍの着色粒子を得た。得られた着色粒子を「トナー粒子７」とする。「トナー粒子７」の界面活性剤残留量は２６ｐｐｍ、凝集剤から導入された残留カルシウム量は８５００ｐｐｍであった。
【０２５３】
（トナー粒子８の作製）
塩化マグネシウム６水和物１２．１ｇの代わりに塩化アルミニウム４．１ｇを使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「トナー粒子８」とする。「トナー粒子８」の界面活性剤残留量は７６ｐｐｍ、凝集剤から導入された残留アルミニウム量は１６０００ｐｐｍであった。
【０２５４】
（トナー粒子９の作製）
洗浄温度４０℃を４７℃にし、イオン交換水で洗浄した後、エタノールで洗浄を加えた以外はトナー粒子１の作製と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「トナー粒子９」する。「トナー粒子９」の界面活性剤残留量は２ｐｐｍ、凝集剤から導入された残留マグネシウム量は２６４ｐｐｍであった。
【０２５５】
（トナー粒子１０の作製）
洗浄温度４０℃を３６℃にし、洗浄水を減らした以外はトナー粒子１の作製と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「トナー粒子１０」とする。「トナー粒子１０」の界面活性剤残留量は１０００ｐｐｍ、凝集剤から導入された残留マグネシウム量は２４０００ｐｐｍであった。
【０２５６】
（トナー粒子１１の作製）
ラテックス１ＨＭＬの代わりにラテックス２ＨＭＬを使用した以外はトナー粒子１の作製と同様にして個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「トナー粒子１１」とする。「トナー粒子１１」の界面活性剤残留量は３６ｐｐｍ、凝集剤から導入された残留マグネシウム量は４０００ｐｐｍであった。
【０２５７】
（比較用のトナー粒子１の作製）
ラテックス１ＨＭＬの代わりにラテックス２ＨＭＬを使用し、着色粒子の分散にドデシル硫酸ナトリウムを使用した以外はトナー粒子１の作製と同様にして個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「比較用トナー粒子１」とする。「比較用トナー粒子１」の界面活性剤残留量は３８ｐｐｍ、凝集剤から導入された残留マグネシウム量は６５００ｐｐｍであった。
【０２５８】
（比較用トナー粒子２の作製）
化合物（１０１）の代わりに下記化合物（１０７）５９．０ｇを使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「比較用トナー粒子２」とする。「比較用トナー粒子２」の界面活性剤残留量は５３ｐｐｍ、凝集剤から導入された残留マグネシウム量は８４００ｐｐｍであった。
【０２５９】
化合物（１０７）：Ｃ₁₂Ｈ₂₅（Ｏ（ＣＨ₂）₁₀）₂ＯＳＯ₃Ｎａ
（比較用トナー粒子３の作製）
化合物（１０１）の代わりに化合物（１０８）５９．０ｇを使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「比較用トナー粒子３」とする。「比較用トナー粒子３」の界面活性剤残留量は４８ｐｐｍ、凝集剤から導入された残留マグネシウム量は６３４０ｐｐｍであった。
【０２６０】
化合物（１０８）：Ｃ₁₀Ｈ₂₁（ＯＣＨ₂ＣＨ₂）₁₂ＯＳＯ₃Ｎａ
（比較用トナー粒子４の作製）
化合物（１０１）の代わりに化合物（１０９）５９．０ｇを使用した以外はトナー粒子１の作製と同様にして、個数平均粒径５．７μｍの着色粒子を得た。得られた着色粒子を「比較用トナー粒子４」とする。「比較用トナー粒子４」の界面活性剤残留量は４６ｐｐｍ、凝集剤から導入された残留マグネシウム量は８０５０ｐｐｍであった。
【０２６１】
化合物（１０９）：Ｃ₂₈Ｈ₅₇（ＯＣＨ₂ＣＨ₂）₂ＯＳＯ₃Ｎａ
得られたトナー粒子の物理的特性、化学的特性を表１、表２に示す。
【０２６２】
【表１】

【０２６３】
【表２】

【０２６４】
以上のようにして得られたトナー粒子１〜１１、比較用トナー１〜４の各々に、疎水性シリカ（数平均一次粒子径１０ｎｍ、疎水化度６３）を１．０質量％となる割合で添加するとともに、疎水性酸化チタン（数平均一次粒子径２５ｎｍ、疎水化度６０）を１．２質量％となる割合でそれぞれ添加し、ヘンシェルミキサーにより混合した。
【０２６５】
なお、これらのトナー粒子について、疎水性シリカおよび疎水性酸化チタンの添加によっては、その形状および粒径は変化しない。
【０２６６】
疎水性シリカおよび疎水性酸化チタンが添加されたトナー粒子の各々と、シリコーン樹脂を被覆した体積平均粒径６０μｍのフェライトキャリアとを混合し、トナー濃度が６質量％の現像剤を調製した。これらの現像剤を、トナー粒子１〜１１、比較用トナー粒子１〜４に対応して、現像剤１〜１１（本発明）、現像剤１２〜１５（比較用）とする。
【０２６７】
得られた現像剤の各々について下記のように特性評価を行った。
《画像濃度、カブリ、転写率、ハーフトーンの均質性の評価》
市販のデジタル複写機コニカＳｔｉｏｓ７０７５を評価機として使用し、高温常湿環境（３３℃、５０％ＲＨ）にてブラックのソリッド画像及び画像濃度、０．４のハーフトーン画像、及び白地画像を連続で印字し、ソリッド画像の最高画像濃度、及び白地部の汚れ「カブリ」の濃度をマクベス反射濃度計で判定した。「転写率」は、感光体上に６０ｍｇ／ｃｍ²の画像を形成し、転写剤である紙に転写された単位面積当たりの付着量を測定した。８０％以上であれば、画像濃度の均一性が固く良好となる。また、ハーフトーンの均質性は目視で判定した。２０人中１５人以上が好むとしたものを「◎」、２０人中１０以上が好むとしたものを「○」、２０人中５人以上が好むとしたものを「△」、「好む」と判定したのが２０人中３人未満を「×」とした。画像汚れ「カブリ」の発生した時点の枚数及び感光体に対する付着物が発生した時点の枚数を記録した。
【０２６８】
《ライン幅評価：細線再現性評価》
２ドットラインの画像信号に対応するライン画像のライン幅を印字評価システム「ＲＴ２０００」（ヤーマン（株）製）によって測定した。１枚目の形成画像のライン幅および２０万枚目の形成画像のライン幅の何れもが２００μｍ以下であり、かつ、ライン幅の変化が１０μｍ未満であれば、細線再現性は問題ないといえる。
【０２６９】
上記の特性評価結果を表３に示す。
【０２７０】
【表３】

【０２７１】
表３から、比較の試料と比べて本発明の試料は画像濃度が高く、低カブリであり、転写率、ハーフトーンの均質性が良好であり、且つ、細線再現性に優れていることが明らかである。
【０２７２】
【発明の効果】
本発明により、画像濃度が高く、低カブリであり、転写率、ハーフトーンの均質性が共に良好であり、且つ、細線再現性に優れた静電荷像現像用トナー、それを用いる画像記録方法、画像形成方法を提供することが出来た。
【図面の簡単な説明】
【図１】（ａ）は、角のないトナー粒子の投影像を示す説明図であり、（ｂ）および（ｃ）は、それぞれ角のあるトナー粒子の投影像を示す説明図である。
【図２】本発明において使用する定着装置の一例を示す断面図を表す。
【符号の説明】
８ 記録材
１０ 加熱ローラ
１１ 芯金
１２ 被覆層
１３ 加熱部材
２０ 加圧ロール
２１ 芯金
２２ 被覆層
Ｔ 記録材上に形成されたトナー像[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner for developing an electrostatic image, a method for producing the same, and an image forming method.
[0002]
[Prior art]
Today, electrostatic latent image developing methods represented by electrophotography are widely used in image forming methods such as printers, copying machines, and facsimiles.
[0003]
This is because it is a highly complete method for stably obtaining high-speed and high-quality images, but there are still some problems.
[0004]
For example, conventionally, in a toner prepared by a pulverization method, the material dispersed in the toner is unevenly present on the fracture surface, the surface property between the toners is difficult to be constant, and variations in the transfer process are likely to occur. There is a problem that color reproducibility as a color image is lowered.
[0005]
On the other hand, the electrostatic latent image developing toner is desired to have a small particle size from the viewpoint of high image quality. In recent years, polymerization toner has been actively developed as a method for producing a small particle size toner. In this polymerization method, resin particles and, if necessary, colorant particles are associated or salted out, agglomerated, and fused to prepare an amorphous toner, or radically polymerizable monomer and colorant are dispersed. Then, there is a method in which droplets are dispersed in an aqueous medium or the like so as to have a desired toner particle size, and suspension polymerization is performed.
[0006]
However, since the toner particles produced by applying the suspension polymerization method can form a spherical toner having a uniform surface property, the uniformity among the toners is high, but the shape is spherical, so the latent particles are latent. Since the adhesion to the image carrier is increased, there is a problem that transferability is lowered.
[0007]
Therefore, in JP-A-11-194540, resin particles polymerized in an aqueous medium containing a surfactant are treated with an aggregating agent having a critical aggregation concentration or higher of the resin particles and an organic solvent infinitely soluble in water. Disclosed are non-spherical particles characterized in that they are made.
[0008]
In the technique described above, by using a divalent or trivalent metal salt as the flocculant, an image having excellent shape uniformity and charge amount uniformity and high sharpness can be obtained. Due to the presence of the metal salt, the Kraft point of the surfactant is increased, and a hardly soluble precipitate is formed in water. This precipitate is present in a state where the colored particles, that is, the toner adheres to the toner after the toner is separated from the aqueous medium, the fog is likely to occur under high temperature and high humidity, and the transferability is liable to deteriorate. there were.
[0009]
On the other hand, it is necessary to control the molecular weight distribution of the toner resin from the viewpoint of stabilizing the fixing property of the toner. For example, in order to suppress high temperature offset, it is necessary to improve the elastic modulus at high temperature, and it is preferable to increase the high molecular weight component. On the other hand, in order to improve adhesion to an image forming support (recording material or recording paper) such as paper, it is preferable to increase the low molecular weight component. In order to satisfy such contradictory functions, it is necessary to increase the molecular weight distribution of the resin. Therefore, there has been a demand for a solution to the above-described problems.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to develop a toner for developing an electrostatic image having high image density, low fog, good transfer rate and halftone uniformity, and excellent fine line reproducibility, and image recording using the same And providing an image forming method.
[0011]
[Means for Solving the Problems]
  The above objects of the present invention are the following items 1 to 1.13Achieved by.
[0012]
In the prior art, it has been considered that the surfactant and metal element contained in the aqueous medium used in the production process remain in the produced toner in terms of toner performance.
[0013]
However, the present inventors have achieved improvement in toner performance by leaving specific amounts of these surfactants and metal elements in the toner, which cannot be predicted from the conventional technical idea.
[0014]
1. A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of the surfactant represented by the general formula (1). A toner for developing an electrostatic image, wherein the toner is produced through a process of depositing, aggregating and fusing.
[0015]
2. A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of the surfactant represented by the general formula (1). A surfactant that is manufactured through a step of separating, agglomerating, and fusing, separating the resin particles from the aqueous medium, and drying the resin particles, and the resin particles are represented by the general formula (1) 2. The toner for developing an electrostatic charge image according to 1 above, containing 1 to 1000 ppm.
[0016]
3. A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of the surfactant represented by the general formula (2). A toner for developing an electrostatic image, wherein the toner is produced through a process of depositing, aggregating and fusing.
[0017]
4). A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of the surfactant represented by the general formula (2). A surfactant that is manufactured through a step of separating, agglomerating, and fusing, separating the resin particles from the aqueous medium, and drying the resin particles, and the resin particles are represented by the general formula (2) 3. The toner for developing an electrostatic charge image according to 3 above, wherein the toner is 1 to 1000 ppm.
[0018]
5. A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles. In the aqueous medium, the surfactant represented by the general formula (1) or the general formula (2) and a divalent compound are prepared. Alternatively, the resin particles are produced through a step of salting out, agglomerating and fusing the resin particles in the presence of a trivalent metal salt, and then a step of separating and drying the resin particles from the aqueous medium. 1 to 1000 ppm of the surfactant represented by the general formula (1) or the general formula (2), and a total of 250 to 20000 ppm of divalent or trivalent metal elements used as a flocculant. 5. The electrostatic charge image developing toner according to any one of 1 to 4 above.
[0019]
6). 6. The electrostatic image developing toner according to 5 above, containing a total of 350 to 35000 ppm of a divalent or trivalent metal element used as an aggregating agent and a monovalent metal element added as an aggregation terminator.
[0022]
  7).65. The toner particles having a shape factor in the range of 1.0 to 1.6 are 65% by number or more.6The toner for developing an electrostatic image according to any one of the above.
[0023]
  8).65. The toner particles having a shape factor in the range of 1.2 to 1.6 are 65% by number or more.7The toner for developing an electrostatic image according to any one of the above.
[0024]
  9.The number of toner particles having no corners is 50% by number or more.8The toner for developing an electrostatic image according to any one of the above.
[0025]
  10.The number average particle diameter of the toner is 3 to 8 μm.9The toner for developing an electrostatic image according to any one of the above.
[0026]
  11.When the particle diameter of the toner particles is D (μm), the histogram showing the particle size distribution on the basis of the natural logarithm lnD on the horizontal axis and classifying the horizontal axis at intervals of 0.23 is included in the most frequent class. The sum (M) of the relative frequency (m1) of the toner particles and the relative frequency (m2) of the toner particles contained in the next most frequent class is 70% or more. 1 to10The toner for developing an electrostatic image according to any one of the above.
[0027]
  12 In producing the toner for developing an electrostatic charge image according to any one of 1 to 11, a polymerizable monomer is polymerized in an aqueous medium to prepare a resin particle dispersion, A step of salting out, aggregating and fusing the resin particles in the presence of the surfactant represented by the general formula (1) or the general formula (2) and a divalent metal salt or a trivalent metal salt, A method for producing a toner for developing an electrostatic charge image, comprising a step of separating and drying resin particles from the aqueous medium.
[0032]
  13.A step of forming an electrostatic charge image on the electrostatic charge image carrier, a step of developing the electrostatic charge image with a developer containing toner for developing an electrostatic charge image to form a toner image, and the toner image on the transfer member. 12. An image forming method comprising the step of transferring, wherein the electrostatic image developing toner according to any one of 1 to 11 is used as the electrostatic image developing toner.
[0033]
Hereinafter, the present invention will be described in detail.
The present invention provides a dispersion of resin particles by polymerizing a polymerizable monomer in an aqueous medium, and the resin particles are polyoxyethylene alkyl ether having the specific structure according to claim 1 or claim 3. An electrostatic charge image developing toner produced by the steps of salting out, agglomerating and fusing the resin particles in the presence of a sulfate ester salt, and the electrostatic charge image developing toner of the present invention Compared to toners prepared using conventionally known emulsion polymerization methods and suspension polymerization methods, the shape uniformity and charge amount distribution are good, the image sharpness is excellent, and fogging occurs at high temperatures and high humidity. It was found that a toner having no transfer and excellent transferability can be obtained. In the salting out, agglomeration, and fusion processes, it is preferable to use a divalent or trivalent metal salt as the aggregating agent.
[0034]
It is represented by the general formula (1) and the general formula (2) existing in the preparation of a dispersion of resin particles according to the toner for developing an electrostatic charge image of the present invention, salting out, agglomeration and fusion of the important particles. The surfactant will be described.
[0035]
In the general formulas (1) and (2), R₁Represents an alkyl group or arylalkyl group having 6 to 22 carbon atoms, preferably an alkyl group or arylalkyl group having 8 to 20 carbon atoms, more preferably an alkyl group or arylalkyl group having 9 to 16 carbon atoms. is there.
[0036]
R₁As the alkyl group having 6 to 22 carbon atoms represented by, for example, n-hexyl group, n-heptyl group, n-octyl group, n-decyl group, n-undecyl group, n-hexadecyl group, cyclopropyl group , Cyclopentyl group, cyclohexyl group and the like.
[0037]
R₁Examples of the arylalkyl group represented by the formula include a benzyl group, a diphenylmethyl group, a cinnamyl group, a styryl group, a trityl group, and a phenethyl group.
[0038]
In the general formulas (1) and (2), R₂Represents an alkylene group having 2 to 6 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms.
[0039]
R₂Examples of the alkylene group having 2 to 6 carbon atoms represented by: ethylene group, trimethylene group, tetramethylene group, propylene group, ethylethylene group and the like.
[0040]
In general formula (1), (2), n is an integer of 1-11, Preferably it is 2-10, More preferably, it is 2-5, Most preferably, it is 2-3.
[0041]
In the general formulas (1) and (2), examples of the monovalent metal element represented by M include sodium, potassium, and lithium. Of these, sodium is preferably used.
[0042]
Specific examples of the surfactants represented by the general formulas (1) and (2) are shown below, but the present invention is not limited to these.
[0043]
Compound (101): C_TenH_{twenty one}(OCH₂CH₂)₂OSO_ThreeNa
Compound (102): C_TenH_{twenty one}(OCH₂CH₂)_ThreeOSO_ThreeNa
Compound (103): C_TenH_{twenty one}(OCH₂CH₂)₂SO_ThreeNa
Compound (104): C_TenH_{twenty one}(OCH₂CH₂)_ThreeSO_ThreeNa
Compound (105): C₈H₁₇(OCH₂CH (CH_Three))₂OSO_ThreeNa
Compound (106): C₁₈H₃₇(OCH₂CH₂)₂OSO_ThreeNa
In the present invention, the charge holding function of the toner is maintained in a good state, the occurrence of fogging at high temperature and high quality is suppressed, and from the viewpoint of improving transferability, the increase in charge amount at low temperature and low humidity is also suppressed, and the development amount From the viewpoint of stabilizing the above, the content of the surfactant represented by the general formulas (1) and (2) in the toner for developing an electrostatic image of the present invention is preferably 1 to 1000 ppm, More preferably, it is 5-500 ppm, Most preferably, it is 7-100 ppm.
[0044]
By incorporating the surfactant in the toner within the above-mentioned range, the charging property of the toner for developing an electrostatic charge image of the present invention is not affected by the influence of the environment and is always applied and maintained uniformly and stably. I can do it.
[0045]
The method for measuring the content of the surfactant represented by the general formulas (1) and (2) in the toner for developing an electrostatic charge image of the present invention is as follows.
[0046]
1 g of toner is dissolved in 50 ml of chloroform, the surfactant is extracted from the chloroform layer with 100 ml of ion-exchanged water, this chloroform layer is extracted once again with 100 ml of ion-exchanged water, and a total of 200 ml of extract (water layer) is reduced to 500 ml. Dilution, This diluted solution was used as a test solution, colored with methylene blue according to the method defined in JIS 33636, the absorbance was measured, and the content in the toner was measured from a separately prepared calibration curve.
[0047]
Moreover, the structure of the surfactant represented by the general formulas (1) and (2)¹The structure was analyzed by H-NMR.
[0048]
In the present invention, a metal salt is preferably used as a flocculant in the step of salting out, agglomerating, and fusing resin particles from a dispersion of resin particles prepared in an aqueous medium. Is to use a valent metal salt as a flocculant. The reason is that the divalent and trivalent metal salts have a smaller critical aggregation concentration (coagulation value or coagulation point) than the monovalent metal salts.
[0049]
The metal salt used as the flocculant or the aggregation terminator according to the present invention will be described.
[0050]
Examples of the metal salt include monovalent metals such as alkali metal salts such as sodium, potassium and lithium, divalent metals such as alkaline earth metal salts such as calcium and magnesium, and divalent metals such as manganese and copper. Examples thereof include trivalent metal salts such as salt, iron and aluminum. Specific examples of these metal salts are shown below.
[0051]
Specific examples of the monovalent metal salt include sodium chloride, potassium chloride, lithium chloride and the like. Examples of the metal salt of the divalent metal include magnesium chloride, calcium chloride, calcium nitrate, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate and the like. Examples of the trivalent metal salt include aluminum chloride and iron chloride. These are appropriately selected according to the purpose.
[0052]
The above-mentioned critical aggregation concentration is an index relating to the stability of the dispersion in the aqueous dispersion, and indicates the concentration at which aggregation occurs when a flocculant is added. This critical coagulation concentration varies greatly depending on the latex itself and the dispersant. For example, it is described in Seizo Okamura et al., Polymer Chemistry 17,601 (1960), etc., and the value can be known by following these descriptions.
[0053]
As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ potential of the dispersion is measured, and the salt concentration at the point where the ζ potential starts to change is defined as the critical aggregation concentration. It is also possible to do.
[0054]
The polymer fine particle dispersion is treated with the metal salt described above according to the present invention so as to have a concentration equal to or higher than the critical aggregation concentration. At this time, as a matter of course, whether the metal salt is added directly or as an aqueous solution is arbitrarily selected according to the purpose. When added as an aqueous solution, the added metal salt must be equal to or higher than the critical aggregation concentration of the polymer particles with respect to the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution.
[0055]
The concentration of the metal salt used as the flocculant may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.
[0056]
In addition, a dispersion liquid in which composite resin particles (the case where the particles have a multilayer structure or other constituents such as additives are included in the particles are referred to as composite resin particles) or colorant particles are dispersed. The temperature of the dispersion when adding the flocculant therein is preferably not higher than the glass transition temperature (Tg) of the composite resin particles, and specifically, preferably in the range of 5 to 55 ° C. Preferably it is set as 10 to 45 degreeC.
[0057]
When the temperature of the dispersion liquid when adding the flocculant is equal to or higher than the glass transition temperature (Tg) of the composite resin particles, it is difficult to control the particle size, and large particles are likely to be generated.
[0058]
In the salting out, agglomerating and fusing steps, when the temperature of the dispersion in which the composite resin particles and the colorant particles are dispersed is equal to or lower than the glass transition temperature (Tg) of the composite resin particles, the dispersion It is preferable to add the flocculant while stirring the liquid, and then immediately start heating the dispersion to a temperature equal to or higher than the glass transition temperature (Tg) of the composite resin particles.
[0059]
In the present invention, resin particles and a colorant are salted out, aggregated, and fused in an aqueous medium to obtain colored particles (referred to as toner particles in the present invention), and then the toner particles are separated from the aqueous medium. When performing, it is preferable to carry out at the temperature more than the craft point of the surfactant which exists in an aqueous medium, More preferably, it is carrying out in the temperature range of a craft point-(craft point +20 degreeC).
[0060]
The Kraft point is a temperature at which an aqueous solution containing a surfactant starts to become cloudy, and the Kraft point is measured as follows.
[0061]
<Measurement of craft point>
A solution was prepared by adding the actual amount of the flocculant to the aqueous medium, that is, the surfactant solution used in the salting out, agglomeration and fusion processes, and this solution was stored at 1 ° C. for 5 days. The solution was then gradually heated with stirring until clear. The temperature at which the solution becomes clear is defined as the Kraft point.
[0062]
The toner for developing an electrostatic charge image of the present invention is described above in order to stabilize and maintain the chargeability particularly with respect to the environment from the viewpoint of suppressing excessive charge to the toner particles and imparting uniform chargeability. It is preferable to contain 250 to 20000 ppm, more preferably 800 to 5000 ppm in the toner.
[0063]
Moreover, in this invention, it is preferable that the total value of the bivalent (trivalent) metal element used for a coagulant | flocculant and the monovalent | monohydric metal element added as an aggregation terminator mentioned later is 350-35000 ppm.
[0064]
The residual amount of metal ions in the toner is measured using a fluorescent X-ray analyzer “System 3270 type” (manufactured by Rigaku Denki Kogyo Co., Ltd.), and the metal species of the metal salt used as a flocculant (for example, calcium chloride It can be determined by measuring the intensity of the fluorescent X-ray emitted from the derived calcium or the like. As a specific measurement method, a plurality of toners having a known content ratio of the flocculant metal salt are prepared, each toner 5g is pelletized, the content ratio (mass ppm) of the flocculant metal salt, and the metal species of the metal salt The relationship (calibration curve) with the fluorescent X-ray intensity (peak intensity) is measured. Next, the toner (sample) whose content of the flocculant metal salt is to be measured is similarly pelletized, and the fluorescent X-ray intensity from the metal species of the flocculant metal salt is measured. Amount "can be obtained.
[0065]
A method for producing the toner for developing an electrostatic charge image of the present invention will be described.
The toner of the present invention forms composite resin particles in the absence of a colorant, adds a dispersion of colorant particles to a dispersion of the composite resin particles, and salting out the composite resin particles and the colorant particles. It is prepared by agglomeration and fusion.
[0066]
Thus, the polymerization reaction for obtaining the composite resin particles is not inhibited by preparing the composite resin particles in a system in which no colorant is present. Therefore, according to the toner of the present invention, the excellent offset resistance is not impaired, and the fixing device is not contaminated or the image is not stained due to the accumulation of toner.
[0067]
Further, as a result of the polymerization reaction for obtaining the composite resin particles being reliably performed, no monomer or oligomer remains in the obtained toner particles, and the heat fixing step of the image forming method using the toner In this case, no odor is generated.
[0068]
Furthermore, since the surface characteristics of the obtained toner particles are uniform and the charge amount distribution is sharp, an image with excellent sharpness can be formed over a long period of time.
[0069]
The “composite resin particle” constituting the toner of the present invention is one or more composed of a resin having a different molecular weight and / or composition from the resin forming the core particle so as to cover the surface of the core particle composed of the resin. The resin particles having a multilayer structure in which the coating layer is formed.
[0070]
Further, the “central part (core)” of the composite resin particle refers to “core particle” constituting the composite resin particle.
[0071]
The “outer layer (shell)” of the composite resin particle refers to the outermost layer among “one or more coating layers” constituting the composite resin particle.
[0072]
The “intermediate layer” of the composite resin particles refers to a coating layer formed between the central portion (core) and the outer layer (shell).
[0073]
The molecular weight distribution of the composite resin particles is not monodisperse, and the composite resin particles usually have a molecular weight gradient from the center (core) to the outer layer (shell).
[0074]
In the present invention, it is preferable to use a “multistage polymerization method” in order to obtain composite resin particles from the viewpoint of molecular weight distribution control, that is, from the viewpoint of securing fixing strength and offset resistance. In the present invention, the “multi-stage polymerization method” for obtaining composite resin particles means a single amount in the presence of resin particles (n) obtained by polymerizing monomer (n) (n-th stage). The body (n + 1) is polymerized (n + 1 stage), and the polymer of the monomer (n + 1) is dispersed and / or composition on the surface of the resin particle (n). A method of forming a coating layer (n + 1) made of different resins).
[0075]
Here, when the resin particle (n) is a core particle (n = 1), it becomes “two-stage polymerization method”, and when the resin particle (n) is a composite resin particle (n ≧ 2), It becomes a multistage polymerization method of three or more stages.
[0076]
A plurality of resins having different compositions and / or molecular weights are present in the composite resin particles obtained by the multistage polymerization method. Therefore, the toner obtained by salting out, aggregating, and fusing the composite resin particles and the colorant particles has extremely small variations in composition, molecular weight, and surface characteristics among the toner particles.
[0077]
According to such a toner having a uniform composition, molecular weight, and surface characteristics between toner particles, an image forming method including a fixing process using a contact heating method maintains good adhesion (high fixing strength) to an image support. However, it is possible to improve the anti-offset property and the anti-winding property, and an image having an appropriate gloss can be obtained.
[0078]
An example of the method for producing the toner for developing an electrostatic charge image of the present invention is specifically shown as follows:
(1) Multistage polymerization step (I) for obtaining composite resin particles prepared so that the release agent and / or crystalline polyester is contained in a region (center portion or intermediate layer) other than the outermost layer,
(2) salting out, aggregating and fusing the composite resin particles and the colorant particles to obtain toner particles (II)
(3) A filtration and washing process for separating the toner particles from the dispersion system of the toner particles and removing the surfactant from the toner particles.
(4) a drying step of drying the washed toner particles;
(5) A step of adding an external additive to the dried toner particles.
[0079]
Hereinafter, each step will be described.
<< Multistage polymerization process (I) >>
The multistage polymerization step (I) is a step of producing composite resin particles by a multistage polymerization method in which a coating layer (n + 1) made of a polymer of the monomer (n + 1) is formed on the surface of the resin particles (n). . Here, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoint of production stability and crushing strength of the obtained toner.
[0080]
Hereinafter, the two-stage polymerization method and the three-stage polymerization method, which are representative examples of the multistage polymerization method, will be described.
[0081]
<Description of the two-stage polymerization method>
The two-stage polymerization method is a method for producing composite resin particles composed of a central portion (core) formed from a high molecular weight resin containing a release agent and an outer layer (shell) formed from a low molecular weight resin. is there. That is, the composite resin particles obtained by the two-stage polymerization method are composed of a core and a single coating layer.
[0082]
This method will be described in detail. First, a monomer solution obtained by dissolving a release agent in a monomer (H) is dispersed in oil droplets in an aqueous medium (an aqueous solution of a surfactant). By subjecting this system to a polymerization treatment (first stage polymerization), a dispersion of high molecular weight resin particles (H) containing a release agent is prepared.
[0083]
Next, a polymerization initiator and a monomer (L) for obtaining a low molecular weight resin are added to the dispersion of the resin particles (H), and the monomer (L) is added in the presence of the resin particles (H). L) is polymerized (second-stage polymerization) to form a coating layer (L) made of a low molecular weight resin (polymer of monomer (L)) on the surface of the resin particles (H). .
[0084]
<Description of three-stage polymerization method>
In the three-stage polymerization method, composite resin particles composed of a central portion (core) formed from a high molecular weight resin, an intermediate layer containing a release agent, and an outer layer (shell) formed from a low molecular weight resin are formed. It is a manufacturing method. That is, the composite resin particles obtained by the three-stage polymerization method are composed of a core and two coating layers.
[0085]
This method will be specifically described. First, a dispersion of resin particles (H) obtained by a polymerization process (first-stage polymerization) according to a conventional method is added to an aqueous medium (an aqueous solution of a surfactant). In addition, by dispersing oil droplets of a monomer solution obtained by dissolving a release agent in the monomer (M) in the aqueous medium, the system is polymerized (second-stage polymerization). A composite resin obtained by forming a coating layer (M) (intermediate layer) made of a resin (monomer (M) polymer) containing a release agent on the surface of the resin particles (H) (core particles). A dispersion of particles [high molecular weight resin (H) -intermediate molecular weight resin (M)] is prepared.
[0086]
Next, a polymerization initiator and a monomer (L) for obtaining a low molecular weight resin are added to the resulting dispersion of composite resin particles, and the monomer (L) is added in the presence of the composite resin particles. Is subjected to polymerization treatment (third-stage polymerization) to form a coating layer (L) made of a low molecular weight resin (polymer of monomer (L)) on the surface of the composite resin particles.
[0087]
In this three-stage polymerization method, when the coating layer (M) is formed on the surface of the resin particles (H), the dispersion of the resin particles (H) is added to an aqueous medium (an aqueous solution of a surfactant) Employing a method in which a monomer solution obtained by dissolving a release agent in the monomer (M) is dispersed in oil droplets in the aqueous medium, and then this system is polymerized (second stage polymerization). Thus, the release agent can be finely and uniformly dispersed.
[0088]
In addition, as for the addition process of the dispersion liquid of the resin particles (H) and the oil droplet dispersion process of the monomer solution, any of them may be performed in advance as described below, or may be performed simultaneously. .
[0089]
(A) When forming the intermediate layer constituting the composite resin particles, after adding the resin particles to be the central part (core) of the composite resin particles into the aqueous solution of the surfactant, the release agent is added to the aqueous solution. A mode in which a monomer composition containing a crystalline polyester is dispersed and this system is polymerized.
(B) When forming the intermediate layer constituting the composite resin particles, after dispersing the monomer composition containing the release agent / crystalline polyester in an aqueous solution of a surfactant, in the aqueous solution, A mode in which resin particles to be the central part (core) of the composite resin particles are added and this system is polymerized,
(C) When forming the intermediate layer constituting the composite resin particles, the resin particles to be the central part (core) of the composite resin particles are added to the aqueous solution of the surfactant, and at the same time, the release agent is added to the aqueous solution. / A mode in which a monomer composition containing a crystalline polyester is dispersed and this system is polymerized is included.
[0090]
As a method of forming resin particles (core particles) or coating layer (intermediate layer) containing a release agent, the release agent is dissolved in a monomer, and the resulting monomer solution is oil-dropped in an aqueous medium. A method of obtaining latex particles by dispersing and polymerizing this system can be employed.
[0091]
Here, the “aqueous medium” refers to a medium composed of 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and alcohol-based organic solvents that do not dissolve the resulting resin are preferable.
[0092]
As a suitable polymerization method for forming resin particles or a coating layer containing a release agent, a release agent is used as a monomer in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. The monomer solution is dissolved in oil droplets using mechanical energy to prepare a dispersion liquid, and a water-soluble polymerization initiator is added to the obtained dispersion liquid to generate radicals in the oil droplets. Examples thereof include a polymerization method (hereinafter referred to as “miniemulsion method”). Instead of adding a water-soluble polymerization initiator, or while adding the water-soluble polymerization initiator, an oil-soluble polymerization initiator may be added to the monomer solution.
[0093]
According to the mini-emulsion method that mechanically forms oil droplets, unlike the usual emulsion polymerization method, the release agent dissolved in the oil phase is not detached, and the resin particles or coating layer formed A sufficient amount of the release agent can be introduced.
[0094]
Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited, and a stirring device “CLEARMIX” equipped with a rotor that rotates at high speed (M Technique Co., Ltd.) Product), ultrasonic dispersers, mechanical homogenizers, Manton gorin, pressure homogenizers, and the like. The dispersed particle diameter is 10 to 1000 nm, preferably 50 to 1000 nm, and more preferably 30 to 300 nm.
[0095]
A known method such as an emulsion polymerization method, a suspension polymerization method, or a seed polymerization method can also be employed as a polymerization method for forming resin particles or a coating layer containing a release agent. These polymerization methods can also be employed to obtain resin particles (core particles) or coating layers constituting the composite resin particles that do not contain a release agent and crystalline polyester.
[0096]
The particle diameter of the composite resin particles obtained in the polymerization step (I) is in the range of 10 to 1000 nm as a weight average particle diameter measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). It is preferable that it exists in.
[0097]
Moreover, it is preferable that the glass transition temperature (Tg) of a composite resin particle exists in the range of 48-74 degreeC, More preferably, it is 52-64 degreeC. The softening point of the composite resin particles is preferably in the range of 95 to 140 ° C.
[0098]
<< Step of salting out, agglomerating and fusing (II) >>
In the salting out, agglomerating and fusing step (II), the composite resin particles obtained in the multistage polymerization step (I) and the colorant particles are salted out, agglomerated and fused (salting out and fusing). At the same time) to obtain irregularly shaped (non-spherical) toner particles.
[0099]
In the salting out, agglomerating and fusing step (II), the additive particles such as the charge control agent (fine particles having a number average primary particle diameter of about 10 to 1000 nm) are salted together with the composite resin particles and the colorant particles. It may be deposited, agglomerated or fused.
[0100]
The colorant particles may be surface modified. Here, as the surface modifier, a conventionally known one can be used.
[0101]
The colorant particles are subjected to salting out, aggregation, and fusion treatment in a state of being dispersed in an aqueous medium. Examples of the aqueous medium in which the colorant particles are dispersed include an aqueous solution in which the surfactant is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC).
[0102]
As the surfactant, the same surfactant as that used in the multistage polymerization step (I) can be used.
[0103]
The disperser used for the dispersion treatment of the colorant particles is not particularly limited, but preferably, a stirrer “CLEARMIX” (manufactured by M Technique Co., Ltd.) equipped with a rotor rotating at high speed, an ultrasonic disperser. And a pressure disperser such as a mechanical homogenizer, a manton gourin and a pressure homogenizer, and a medium disperser such as a Getzmann mill and a diamond fine mill.
[0104]
In order to salt out, agglomerate, and fuse the composite resin particles and the colorant particles, in the dispersion in which the composite resin particles and the colorant particles are dispersed, a flocculant having a critical aggregation concentration or more is added, It is preferable to heat this dispersion to a glass transition temperature (Tg) or higher of the composite resin particles.
[0105]
More preferably, a coagulation terminator is used when the composite resin particles reach a desired particle size by the coagulant. As the aggregation terminator, a monovalent metal salt, particularly sodium chloride is preferably used.
[0106]
The temperature range suitable for salting out, agglomerating, and fusing is (Tg + 10) to (Tg + 50 ° C.), particularly preferably (Tg + 15) to (Tg + 40 ° C.). In addition, an organic solvent that is infinitely soluble in water may be added in order to effectively perform fusion.
[0107]
Examples of the “flocculating agent” used for salting out, agglomerating, and fusing include alkali metal salts and alkaline earth metal salts as described above.
[0108]
The salting out and aggregation according to the present invention will be described.
In the present invention, “salting out, agglomeration, fusion” means that salting out (aggregation of particles) and fusion (disappearance of the interface between particles) occur simultaneously, or salting out and fusion occur simultaneously. The act of letting go.
[0109]
In order to perform salting-out and fusion at the same time, it is preferable to agglomerate particles (composite resin particles, colorant particles) under a temperature condition higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. .
[0110]
The toner for developing an electrostatic charge image of the present invention forms composite resin particles in the absence of a colorant, adds a dispersion of the colorant particles to the dispersion of the composite resin particles, and combines the composite resin particles and the colorant particles. Is preferably prepared by salting out, agglomerating and fusing.
[0111]
Thus, the polymerization reaction for obtaining the composite resin particles is not inhibited by preparing the composite resin particles in a system in which no colorant is present. Therefore, according to the toner of the present invention, the excellent offset resistance is not impaired, and the fixing device is not contaminated or the image is not stained due to the accumulation of toner.
[0112]
Further, as a result of the polymerization reaction for obtaining the composite resin particles being reliably performed, no monomer or oligomer remains in the obtained toner particles, and the heat fixing step of the image forming method using the toner In this case, no odor is generated.
[0113]
Furthermore, since the surface characteristics of the obtained toner particles are uniform and the charge amount distribution is sharp, an image with excellent sharpness can be formed over a long period of time. According to such a toner having a uniform composition, molecular weight, and surface characteristics between toner particles, an image forming method including a fixing process using a contact heating method maintains good adhesion (high fixing strength) to an image support. However, it is possible to improve the anti-offset property and the anti-winding property, and an image having an appropriate gloss can be obtained.
[0114]
The release agent used for the toner of the present invention will be described.
The content ratio of the release agent constituting the toner for developing an electrostatic charge image of the present invention is usually 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass.
[0115]
As the release agent, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene or the like may be added, and a preferable release agent is preferably an ester compound represented by the following general formula.
[0116]
General formula
R₁-(OCO-R₂)_n
In the formula, n represents an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4.
[0117]
R₁, R₂Represents a hydrocarbon group which may have a substituent.
R₁: Carbon number = 1-40, preferably 1-20, more preferably 2-5
R₂: Carbon number = 1-40, preferably 16-30, more preferably 18-26
Although the specific example of the ester compound represented by the said general formula is shown below, this invention is not limited to these.
[0118]
[Chemical 1]

[0119]
The amount of the release agent described above and the fixing improver represented by the general formula is 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15%, based on the whole toner for developing electrostatic images. % By mass.
[0120]
The preferred molecular weight, molecular weight range, peak molecular weight, etc. of the resin component constituting the toner for developing an electrostatic charge image of the present invention will be described.
[0121]
The toner of the present invention preferably has a peak or shoulder at 100,000 to 1,000,000 and 1,000 to 50,000, and further has a peak or shoulder of 100,000 to 1,000,000. 25,000 to 150,000, and more preferably in the range of 1,000 to 50,000.
[0122]
The molecular weight of the toner resin has a high molecular weight component having a peak or shoulder in the region of 100,000 to 1,000,000 and a peak or shoulder in the region of 1,000 to less than 50,000. A resin containing at least both low molecular weight components is preferred. More preferably, an intermediate molecular weight resin having a peak or shoulder at a peak molecular weight of 15,000 to 100,000 is used.
[0123]
The molecular weight is measured using GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a column solvent.
[0124]
Specifically, 1 ml of THF is added to 1 mg of a measurement sample, and the mixture is sufficiently dissolved by stirring using a magnetic stirrer at room temperature. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC. The measurement conditions of GPC are measured by stabilizing the column at 40 ° C., flowing THF at a flow rate of 1 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml. As the column, it is preferable to use a combination of commercially available polystyrene gel columns. For example, Shodex GPC KF-801, 802, 803, 804, 805, 806, 807 made by Showa Denko KK, TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation Combinations can be given.
[0125]
As the detector, a refractive index detector (IR detector) or a UV detector is preferably used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points are preferably used as polystyrene for preparing a calibration curve.
[0126]
The filtration / washing process relating to the production of the electrostatic image developing toner of the present invention will be described.
[0127]
In this filtration / washing step, a filtration treatment for filtering the toner particles from the dispersion system of the toner particles obtained in the above step, and a surfactant or an aggregating agent from the filtered toner particles (cake-like aggregate). And a cleaning process for removing deposits.
[0128]
Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.
[0129]
<< Drying process >>
This step is a step of drying the washed toner particles.
[0130]
Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like.
[0131]
The water content of the dried toner particles is preferably 5% by mass or less, and more preferably 2% by mass or less.
[0132]
In addition, when the toner particles subjected to the drying treatment are aggregated by weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.
[0133]
The polymerizable monomer according to the present invention will be described.
(1) Hydrophobic monomer
The hydrophobic monomer constituting the monomer component is not particularly limited, and conventionally known monomers can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.
[0134]
Specifically, monovinyl aromatic monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.
[0135]
Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.
[0136]
Examples of acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, methyl methacrylate, methacrylic acid. Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.
[0137]
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.
[0138]
Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.
[0139]
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.
[0140]
Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.
[0141]
(2) Crosslinkable monomer
In order to improve the characteristics of the resin particles, a crosslinkable monomer may be added. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.
[0142]
(3) Monomers having acidic polar groups
Examples of the monomer having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (b) a sulfone group (—SOOH)._ThreeMention may be made of α, β-ethylenically unsaturated compounds having H).
[0143]
Examples of the α, β-ethylenically unsaturated compound (a) having a —COO group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid. Examples thereof include acid monooctyl esters, and metal salts thereof such as Na and Zn.
[0144]
(B) Sulfo group (—SO_ThreeExamples of the α, β-ethylenically unsaturated compound having (H group) include sulfonated styrene, its Na salt, allylsulfosuccinic acid, octyl allylsulfosuccinate, and its Na salt.
[0145]
The initiator (also referred to as polymerization initiator) used for the polymerization of the polymerizable monomer according to the present invention will be described.
[0146]
The polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, etc.), Examples thereof include peroxide compounds such as hydrogen oxide and benzoyl peroxide.
[0147]
Furthermore, the polymerization initiator can be combined with a reducing agent as necessary to form a redox initiator. By using a redox initiator, the polymerization activity is increased, the polymerization temperature is lowered, and the polymerization time can be further shortened.
[0148]
The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator. For example, a range of 50 ° C. to 80 ° C. is used. Moreover, it is also possible to polymerize at room temperature or a temperature close to it by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).
[0149]
The chain transfer agent used in the present invention will be described.
In the present invention, conventionally known generally used chain transfer agents can be used for the purpose of adjusting the molecular weight of the resin particles produced by polymerization of the polymerizable monomer.
[0150]
The chain transfer agent is not particularly limited. In particular, a compound having a mercapto group is preferably used because a toner having a sharp molecular weight distribution can be obtained and storage stability, fixing strength and offset resistance are excellent. For example, a compound having a mercapto group such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan is used.
[0151]
Preferred examples include ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate, thioglycol Examples include acid dodecyl, ethylene glycol thioglycolate, neopentyl glycol thioglycolate, pentaerythritol thioglycolate, and the like.
[0152]
Among these, n-octyl-3-mercaptopropionic acid ester is preferably used from the viewpoint of suppressing odor during toner heat fixing.
[0153]
The colorant according to the present invention will be described.
The colorant relating to the toner for developing an electrostatic charge image of the present invention is salted out together with the resin particles at the time of toner production, at the time of salting out, aggregating and fusing the composite resin particles, from the viewpoint of improving the uniformity of toner charging. The toner particles are preferably aggregated and fused and contained in the toner particles.
[0154]
Examples of the colorant constituting the toner of the present invention (colorant particles used for salting out, agglomeration, and fusion with composite resin particles) include various inorganic pigments, organic pigments, and dyes. A conventionally well-known thing can be used as an inorganic pigment. Specific inorganic pigments are exemplified below.
[0155]
Examples of the black pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.
[0156]
These inorganic pigments can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0157]
When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, it is preferable to add 20 to 120% by mass in the toner from the viewpoint of imparting predetermined magnetic properties.
[0158]
Conventionally known organic pigments and dyes can also be used. Specific organic pigments and dyes are exemplified below.
[0159]
Examples of pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.
[0160]
Examples of the orange or yellow pigment include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 155, C.I. I. And CI Pigment Yellow 156.
[0161]
Examples of pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.
[0162]
As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 etc. can be used, and a mixture thereof can also be used.
[0163]
These organic pigments and dyes can be used alone or in combination as desired. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0164]
The colorant (colorant particles) constituting the electrostatic image developing toner of the present invention may be surface-modified. Here, as the surface modifier, a conventionally known one can be used, and specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent and the like can be preferably used.
[0165]
Silane coupling agents include: methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, alkoxysilane such as diphenyldimethoxysilane, siloxane such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, Vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureidopropyltri An ethoxysilane etc. are mentioned.
[0166]
Examples of titanium coupling agents include TTS, 9S, 38S, 41B, 46B, 55, 138S, and 238S, which are commercially available under the trade name “Plenact” manufactured by Ajinomoto Co., Inc. -1, B-1, TOT, TST, TAA, TAT, TLA, TOG, TBSTA, A-10, TBT, B-2, B-4, B-7, B-10, TBSTA-400, TTS, TOA -30, TSDMA, TTAB, TTOP and the like.
[0167]
Examples of the aluminum coupling agent include “Plenact AL-M” manufactured by Ajinomoto Co., Inc.
[0168]
The addition amount of these surface modifiers is preferably 0.01 to 20% by mass, and more preferably 0.1 to 5% by mass with respect to the colorant.
[0169]
Examples of the method for modifying the surface of the colorant particles include a method in which a surface modifier is added to the dispersion of the colorant particles and this system is heated to react.
[0170]
The surface-modified colorant particles are collected by filtration, washed with the same solvent and filtered, and then dried.
[0171]
The toner particles constituting the toner of the present invention may contain an internal additive other than the release agent such as a charge control agent.
[0172]
Examples of the charge control agent contained in the toner particles include nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof, etc. Is mentioned.
[0173]
The external additive used for the toner of the present invention will be described.
Examples of inorganic fine particles that can be used as an external additive include conventionally known fine particles. Specifically, silica fine particles, titanium fine particles, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic.
[0174]
Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., and HVK-2150 manufactured by Hoechst Co., Ltd. , H-200, commercially available products TS-720, TS-530, TS-610, H-5, MS-5 manufactured by Cabot Corporation.
[0175]
Specific examples of the titanium fine particles include, for example, commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B, MT-500BS, and MT-600 manufactured by Teika Co., Ltd. , MT-600SS, JA-1, commercial products manufactured by Fuji Titanium Co., Ltd. TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T, commercial products IT-S manufactured by Idemitsu Kosan Co., Ltd. IT-OA, IT-OB, IT-OC and the like.
[0176]
Specific examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.
[0177]
Examples of the organic fine particles that can be used as the external additive include spherical fine particles having a number average primary particle diameter of about 10 to 2000 nm. Examples of the constituent material of the organic fine particles include polystyrene, polymethyl methacrylate, and styrene-methyl methacrylate copolymer.
[0178]
Examples of the lubricant that can be used as an external additive include metal salts of higher fatty acids. Specific examples of such higher fatty acid metal salts include zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate, and other stearic acid metal salts; zinc oleate, manganese oleate, iron oleate, olein Oleic acid metal salts such as acid copper and magnesium oleate; palmitate metal salts such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; linoleic acid metal salts such as zinc linoleate and calcium linoleate; ricinol Examples include ricinoleic acid metal salts such as zinc acid and calcium ricinoleate.
[0179]
The addition amount of the external additive is preferably about 0.1 to 5% by mass with respect to the toner.
[0180]
The external additive adding step will be described.
This step is a step of adding an external additive to the dried toner particles.
[0181]
Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.
[0182]
The particle diameter of the electrostatic image developing toner of the present invention will be described.
The particle size of the toner of the present invention is preferably 3 to 10 μm, more preferably 3 to 8 μm in terms of number average particle size. This particle diameter can be controlled by the concentration of the aggregating agent, the amount of organic solvent added, the fusing time, and the polymer composition in the toner production method described in detail later.
[0183]
When the number average particle diameter is 3 to 10 μm, toner particles having high adhesion force that fly and adhere to the heating member and generate offset in the fixing process are reduced, and transfer efficiency is increased and halftone The image quality is improved, and the image quality of fine lines and dots is improved.
[0184]
The number average particle diameter of the toner can be measured using a Coulter Counter TA-II, Coulter Multisizer, SLAD 1100 (Laser Diffraction Particle Size Measuring Device manufactured by Shimadzu Corporation) or the like.
[0185]
In the present invention, a Coulter multisizer is used, and an interface (manufactured by Nikkaki Co., Ltd.) for outputting a particle size distribution and a personal computer are connected. The aperture in the Coulter Multisizer was 100 μm, and the toner volume distribution of 2 μm or more (for example, 2 to 40 μm) was measured to calculate the particle size distribution and average particle size.
[0186]
The shape factor of the toner particles of the present invention will be described.
The shape factor of the toner of the present invention is represented by the following formula and indicates the degree of roundness of the toner particles.
[0187]
Shape factor = ((maximum diameter / 2)²× π) / projection area
Here, the maximum diameter refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines. The projected area refers to the area of the projected image of the toner particles on the plane.
[0188]
In the present invention, this shape factor is obtained by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and then using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. It was measured by performing analysis. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.
[0189]
In (1) and (9) having the above-described configuration, the number of toner particles having a shape factor in the range of 1.0 to 1.6 is preferably 65% by number or more, and more preferably 70% by number or more. is there. More preferably, the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, and more preferably 70% by number or more.
[0190]
When the number of toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more, the triboelectric chargeability on the developer conveying member and the like becomes more uniform, and excessively charged toner is accumulated. In addition, since it becomes easier to replace the toner from the surface of the developer conveying member, problems such as development ghost are less likely to occur. Further, the toner particles are less likely to be crushed, the contamination of the charging member is reduced, and the chargeability of the toner is stabilized.
[0191]
In (16) of the above configuration, it is necessary that the number of toner particles having a shape factor in the range of 1.2 to 1.6 be 65% by number or more, and preferably 70% by number or more. .
[0192]
The method for controlling the shape factor is not particularly limited. For example, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy due to impact force in a gas phase, or a method in which a toner is not dissolved in a solvent and a swirl flow is applied. To prepare a toner having a shape factor of 1.0 to 1.6, or 1.2 to 1.6, and adding the toner into a normal toner so as to be within the range of the present invention. There is. In addition, the overall shape is controlled at the stage of adjusting the so-called polymerization method toner, and the toner whose shape factor is adjusted to 1.0 to 1.6 or 1.2 to 1.6 is similarly added to the normal toner. There is a way to adjust.
[0193]
As the toner of the present invention, when the particle size of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the number-based particle size distribution is divided into a plurality of classes at intervals of 0.23. In the histogram shown, the sum (M) of the relative frequency (m1) of the toner particles included in the most frequent class and the relative frequency (m2) of the toner particles included in the next most frequent class after the most frequent class is 70. % Of the toner is preferable.
[0194]
When the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow. Therefore, selective development can be performed by using the toner in the image forming process. Can be reliably suppressed.
[0195]
In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram was created by transferring the particle size data of the sample measured by the Coulter Multisizer to the computer via the I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.
[0196]
"Measurement condition"
(1) Aperture: 100 μm
(2) Sample preparation method: Electrolyte [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) was added and stirred, and a measurement sample 10-20 mg was added thereto. Add This system is prepared by dispersing for 1 minute with an ultrasonic disperser.
[0197]
The “toner particles without corners” according to the present invention will be described with reference to FIG.
In the toner according to the present invention, the proportion of toner particles having no corners in the toner particles constituting the toner is preferably 50 number% or more, and more preferably 70 number% or more.
[0198]
When the ratio of the toner particles having no corners is 50% by number or more, voids in the transferred toner layer (powder layer) are reduced, fixing property is improved, and offset is hardly generated. In addition, toner particles that easily wear and break and toner particles having a portion where charges are concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed over a long period of time.
[0199]
Here, the “toner particles having no corners” means toner particles having substantially no protrusions that concentrate electric charges or protrusions that easily wear due to stress. Specifically, the following toner particles are used. Is called toner particles having no corners. That is, as shown in FIG. 1A, when the major axis of the toner particle T is L, a circle C having a radius (L / 10) is in contact with the peripheral line of the toner particle T at one point. A case where the circle C does not substantially protrude outside the toner T when the inner side is rolled is referred to as “toner particles having no corners”. “A case where the protrusion does not substantially protrude” refers to a case where the protrusion having the protruding circle is one or less. The “major diameter of toner particles” refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on a plane is sandwiched between two parallel lines. FIGS. 1B and 1C show projected images of toner particles having corners, respectively.
[0200]
The ratio of toner particles having no corners was measured as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 100 toner particles.
[0201]
A method for obtaining toner having no corners is not particularly limited. For example, as described above as a method for controlling the shape factor, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy by impact force in a gas phase, or a toner is dissolved. It can be obtained by adding in a solvent that does not, and applying a swirling flow.
[0202]
The developer used in the present invention will be described.
The toner of the present invention may be used as a one-component developer or a two-component developer.
[0203]
When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.
[0204]
Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.
[0205]
The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
[0206]
The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.
[0207]
The image forming method of the present invention will be described.
The toner of the present invention is an image forming method including the step of fixing an image forming support on which a toner image is formed between a heating roller and a pressure roller constituting a fixing device (the image forming method of the present invention). Method).
[0208]
FIG. 2 is a cross-sectional view showing an example of a fixing device used in the image forming method of the present invention. The fixing device shown in FIG. 2 includes a heating roller 10 and a pressure roller 20 in contact with the heating roller 10. . In FIG. 2, T is a toner image formed on a transfer paper (image forming support).
[0209]
The heating roller 10 has a coating layer 12 made of a fluororesin or an elastic body formed on the surface of the cored bar 11 and includes a heating member 13 made of a linear heater.
[0210]
The core metal 11 is made of metal and has an inner diameter of 10 to 70 mm. Although it does not specifically limit as a metal which comprises the metal core 11, For example, metals, such as iron, aluminum, copper, or these alloys can be mentioned.
[0211]
The thickness of the metal core 11 is set to 0.1 to 15 mm, and is determined in consideration of the balance between the request for energy saving (thinning) and the strength (depending on the constituent materials). For example, in order to maintain the same strength as that of a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the wall thickness needs to be 0.8 mm.
[0212]
Examples of the fluororesin constituting the coating layer 12 include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).
[0213]
The thickness of the coating layer 12 made of a fluororesin is 10 to 500 μm, preferably 20 to 400 μm.
[0214]
When the thickness of the coating layer 12 made of a fluororesin is less than 10 μm, the function as the coating layer cannot be sufficiently exhibited, and the durability as the fixing device cannot be ensured. On the other hand, there is a problem that the surface of the coating layer exceeding 500 μm is easily scratched by paper dust, and toner or the like adheres to the scratched part, thereby causing image smearing.
[0215]
Further, as the elastic body constituting the coating layer 12, it is preferable to use silicone rubber, silicone sponge rubber, etc. having good heat resistance such as LTV, RTV, HTV.
[0216]
The Asker C hardness of the elastic body constituting the coating layer 12 is less than 80 °, preferably less than 60 °.
[0217]
Moreover, the thickness of the coating layer 12 made of an elastic body is 0.1 to 30 mm, preferably 0.1 to 20 mm.
[0218]
When the Asker C hardness of the elastic body constituting the coating layer 12 exceeds 80 ° and when the thickness of the coating layer 12 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is performed. (For example, the effect of improving the color reproducibility by the toner layer at the smoothed interface) cannot be exhibited.
[0219]
As the heating member 13, a halogen heater can be suitably used.
The pressure roller 20 is formed by forming a coating layer 22 made of an elastic body on the surface of the core metal 21. The elastic body constituting the coating layer 22 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubber. The silicone rubber exemplified as the one constituting the coating layer 12 and It is preferable to use silicone sponge rubber.
[0220]
The Asker C hardness of the elastic body constituting the coating layer 22 is less than 80 °, preferably less than 70 °, and more preferably less than 60 °.
[0221]
The thickness of the coating layer 22 is 0.1 to 30 mm, preferably 0.1 to 20 mm.
[0222]
When the Asker C hardness of the elastic body constituting the coating layer 22 exceeds 80 ° and the thickness of the coating layer 22 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is not possible. The effect cannot be demonstrated.
[0223]
Although it does not specifically limit as a material which comprises the core metal 21, Metals, such as aluminum, iron, copper, or those alloys can be mentioned.
[0224]
The contact load (total load) between the heating roller 10 and the pressure roller 20 is usually 40 to 350 N, preferably 50 to 300 N, and more preferably 50 to 250 N. This contact load is defined in consideration of the strength of the heating roller 10 (the thickness of the core metal 11). For example, in a heating roller having a core metal made of iron of 0.3 mm, the contact load should be 250 N or less. Is preferred.
[0225]
Also, from the viewpoint of offset resistance and fixability, the nip width is preferably 4 to 10 mm, and the surface pressure of the nip is preferably 0.6 × 10 5 Pa to 1.5 × 10 5 Pa.
[0226]
An example of fixing conditions by the fixing device shown in FIG. 2 is that the fixing temperature (surface temperature of the heating roller 10) is 150 to 210 ° C., and the fixing linear velocity is 80 to 640 mm / sec.
[0227]
The fixing device used in the present invention may be provided with a cleaning mechanism as necessary. In this case, as a method of supplying silicone oil to the upper roller (heating roller) of the fixing unit, a method of supplying and cleaning with a pad, roller, web or the like impregnated with silicone oil can be used.
[0228]
As the silicone oil, one having high heat resistance is used, and polydimethyl silicone, polyphenylmethyl silicone, polydiphenyl silicone and the like are used. Since a low-viscosity thing will have a large outflow at the time of use, those having a viscosity at 20 ° C. of 1 to 100 Pa · s are preferably used.
[0229]
However, the effect of the present invention is particularly remarkable when the image forming process is included by a fixing device that does not supply silicone oil or that has a very low supply amount of silicone oil. Accordingly, even when silicone oil is supplied, the supply amount is preferably 2 mg / A4 or less.
[0230]
By setting the amount of silicone oil to be 2 mg / A4 or less, the amount of silicone oil attached to the transfer paper (image support) after fixing is reduced, and entry of oil-based pens such as ballpoint pens with silicone oil attached to the transfer paper is completed. There is no difficulty and the writing property is not impaired.
[0231]
Further, it is possible to avoid problems such as a decrease in offset resistance over time due to silicone oil alteration and contamination of the optical system and band electrode due to silicone oil.
[0232]
Here, the amount of silicone oil supplied is such that 100 sheets of transfer paper (A4 size white paper) are continuously passed through the fixing device (between rollers) heated to a predetermined temperature, and the mass change (Δw ) Is calculated (Δw / 100).
[0233]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
[0234]
<Preparation of latex>
(Preparation of latex 1HML)
(1) Preparation of latex (1H) (nuclear particle formation; first stage polymerization)
In a 5000 ml separable flask equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introduction device, a surfactant solution (aqueous medium) in which 7.08 g of the compound (101) was dissolved in 3010 g of ion-exchanged water was charged. The internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
[0235]
To this surfactant solution, an initiator solution in which 9.2 g of a polymerization initiator (potassium persulfate: KPS) was dissolved in 200 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., 70.1 g of styrene, A monomer mixture A consisting of 19.9 g of n-butyl acrylate and 10.9 g of methacrylic acid was added dropwise over 1 hour, and the mixture was heated and stirred at 75 ° C. for 2 hours for polymerization (first stage polymerization). ) To prepare latex (a dispersion of resin particles made of high molecular weight resin). This is designated as latex (1H).
[0236]
(2) Preparation of latex (1HM) (formation of intermediate layer: second stage polymerization)
In a flask equipped with a stirrer, a monomer consisting of 105.6 g styrene, 30.0 g n-butyl acrylate, 6.4 g methacrylic acid, 5.6 g n-octyl-3-mercaptopropionic acid ester To the mixed solution, 72.0 g of the ester compound (19) was added, heated to 80 ° C. and dissolved to prepare a monomer solution B.
[0237]
On the other hand, a surfactant solution in which 1.6 g of the compound (101) was dissolved in 2700 ml of ion-exchanged water was heated to 80 ° C., and the latex (1H) was added to the surfactant solution in an amount of 28 g in terms of solid content. After the addition, the monomer solution B is mixed and dispersed by a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path, and has a uniform dispersed particle size (284 nm). A dispersion (emulsion) containing emulsified particles (oil droplets) was prepared.
[0238]
Next, an initiator solution in which 5.1 g of a polymerization initiator (KPS: potassium persulfate) is dissolved in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water are added to this dispersion (emulsion). This system is polymerized by heating and stirring at 80 ° C. for 3 hours (second-stage polymerization), and latex (the composite resin particle having a structure in which the surface of the resin particle made of high molecular weight resin is coated with the intermediate molecular weight resin) Dispersion) was obtained. This is latex (1HM).
[0239]
(3) Preparation of latex (1HML) (formation of outer layer: third stage polymerization)
To the latex (1HM) obtained above, an initiator solution in which 7.4 g of a polymerization initiator (KPS: potassium persulfate) was dissolved in 200 ml of ion-exchanged water was added, and under a temperature condition of 80 ° C., A monomer mixed solution consisting of 300 g of styrene, 95 g of n-butyl acrylate, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and latex (a central part made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, A dispersion of composite resin particles) having an outer layer made of a molecular weight resin and containing the ester compound (19) in the intermediate layer. This is latex (1HML).
[0240]
The composite resin particles constituting the latex (1HML) had peak molecular weights of 138,000, 80,000 and 13,000, and the weight average particle diameter of the composite resin particles was 122 nm.
[0241]
(Preparation of latex 2HML)
In the preparation of the latex 1HML described above, a latex (a central part composed of a high molecular weight resin and an intermediate molecular weight resin) was used in the same manner except that 7.08 g of sodium dodecyl sulfonate (SDS) was used instead of the compound (101). A dispersion of composite resin particles having an intermediate layer made of and an outer layer made of a low molecular weight resin. This latex is referred to as “latex (2HML)”.
[0242]
The composite resin particles constituting the latex (2HML) had peak molecular weights of 138,000, 80,000 and 12,000, and the weight average particle size of the composite resin particles was 110 nm.
[0243]
<Example of toner production>
(Preparation of toner particles 1)
59.0 g of the compound (101) was dissolved by stirring in 1600 ml of ion-exchanged water. While stirring this solution, 420.0 g of carbon black “Regal 330” (manufactured by Cabot) was gradually added, and then dispersed using “Claremix” (manufactured by M Technique Co., Ltd.). A dispersion 1 of colorant particles (hereinafter referred to as “colorant dispersion 1”) was prepared.
[0244]
When the particle diameter of the colorant particles in the colorant dispersion 1 was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle diameter was 98 nm.
[0245]
420.7 g (converted to solid content) of latex 1HML, 900 g of ion-exchanged water, and 166 g of colorant dispersion 1 were reacted in a reaction vessel equipped with a temperature sensor, a condenser, a nitrogen introducing device, and a stirring device (four The flask was placed in a neck flask) and stirred. After adjusting the internal temperature to 30 ° C., 5N aqueous sodium hydroxide solution was added to this solution to adjust the pH to 11.0.
[0246]
Next, an aqueous solution in which 12.1 g of magnesium chloride hexahydrate was dissolved in 1000 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, temperature increase was started, and the system was heated to 90 ° C. over 6 minutes (temperature increase rate = 10 ° C./min). In this state, the particle size of the associated particles was measured with a “Coulter Counter TA-II”. Was added to stop the particle growth, and the fusion was continued by agitating at a liquid temperature of 85 ° C. for 2 hours as an aging treatment. Then, it cooled to 40 degreeC on the conditions of 8 degreeC / min, hydrochloric acid was added, pH was adjusted to 2.0, and stirring was stopped. The produced associated particles were filtered, washed repeatedly with ion-exchanged water whose temperature was adjusted to 45 ° C., and then dried with hot air at 40 ° C. to obtain colored particles having a number average particle diameter of 5.7 μm. The resulting colored particles are referred to as “toner particles 1”. The residual amount of surfactant in “Toner Particle 1” was 28 ppm, and the amount of residual magnesium introduced from the flocculant was 4500 ppm.
[0247]
  (Preparation of toner particles 2)
  Instead of compound (101)SaidA colored particle having a number average particle diameter of 5.7 μm was obtained in the same manner as in the production of the toner particle 1 except that 59.0 g of the compound (102) was used. The resulting colored particles are referred to as “toner particles 2”. The residual amount of the surfactant in “Toner Particle 2” was 32 ppm, and the amount of residual magnesium introduced from the flocculant was 3600 ppm.
[0248]
  (Preparation of toner particles 3)
  Instead of compound (101)SaidColored particles having a number average particle diameter of 5.8 μm were obtained in the same manner as in the preparation of the toner particles 2 except that 59.0 g of the compound (103) was used. The resulting colored particles are referred to as “toner particles 3”. The residual amount of surfactant in “Toner Particle 3” was 48 ppm, and the amount of residual magnesium introduced from the flocculant was 8870 ppm.
[0249]
  (Preparation of toner particles 4)
  Instead of compound (101)SaidA colored particle having a number average particle diameter of 5.8 μm was obtained in the same manner as in the preparation of the toner particle 1 except that 59.0 g of the compound (104) was used. The resulting colored particles are referred to as “toner particles 4”. The residual amount of surfactant in “Toner Particle 4” was 53 ppm, and the amount of residual magnesium introduced from the flocculant was 7960 ppm.
[0250]
  (Preparation of toner particles 5)
  Instead of compound (101)SaidA colored particle having a number average particle diameter of 5.8 μm was obtained in the same manner as in the production of the toner particle 1 except that 59.0 g of the compound (105) was used. The resulting colored particles are referred to as “toner particles 5”. The residual amount of surfactant in “Toner Particles 5” was 84 ppm, and the amount of residual magnesium introduced from the flocculant was 5050 ppm.
[0251]
  (Preparation of toner particles 6)
  Instead of compound (101)SaidA colored particle having a number average particle diameter of 5.7 μm was obtained in the same manner as in the preparation of the toner particle 1 except that 59.0 g of the compound (106) was used. The resulting colored particles are referred to as “toner particles 6”. The residual amount of surfactant in “Toner Particle 6” was 91 ppm, and the amount of residual magnesium introduced from the flocculant was 5050 ppm.
[0252]
(Preparation of toner particles 7)
Colored particles having a number average particle diameter of 5.8 μm were obtained in the same manner as in the preparation of the toner particles 1 except that 18.2 g of calcium chloride was used instead of 12.1 g of magnesium chloride hexahydrate. The resulting colored particles are referred to as “toner particles 7”. The residual amount of the surfactant in “Toner Particle 7” was 26 ppm, and the amount of residual calcium introduced from the flocculant was 8500 ppm.
[0253]
(Preparation of toner particles 8)
Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the production of the toner particles 1 except that 4.1 g of aluminum chloride was used instead of 12.1 g of magnesium chloride hexahydrate. The resulting colored particles are referred to as “toner particles 8”. The residual amount of surfactant in “Toner Particles 8” was 76 ppm, and the amount of residual aluminum introduced from the flocculant was 16000 ppm.
[0254]
(Preparation of toner particles 9)
Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the production of the toner particles 1 except that the washing temperature was set to 47 ° C., washed with ion exchange water, and then washed with ethanol. The obtained colored particles are designated as “toner particles 9”. The residual amount of the surfactant in “Toner Particles 9” was 2 ppm, and the amount of residual magnesium introduced from the flocculant was 264 ppm.
[0255]
(Preparation of toner particles 10)
Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the production of toner particles 1 except that the washing temperature was set to 36 ° C. and the washing water was reduced. The resulting colored particles are referred to as “toner particles 10”. The residual amount of the surfactant in “Toner Particle 10” was 1000 ppm, and the amount of residual magnesium introduced from the flocculant was 24000 ppm.
[0256]
(Preparation of toner particles 11)
Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the preparation of toner particles 1 except that latex 2HML was used instead of latex 1HML. The resulting colored particles are referred to as “toner particles 11”. The residual amount of the surfactant in “Toner Particles 11” was 36 ppm, and the amount of residual magnesium introduced from the flocculant was 4000 ppm.
[0257]
(Preparation of toner particles 1 for comparison)
Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the production of toner particles 1 except that latex 2HML was used instead of latex 1HML and sodium dodecyl sulfate was used for dispersion of the colored particles. The resulting colored particles are referred to as “Comparative Toner Particles 1”. The surfactant residual amount of “Comparative Toner Particle 1” was 38 ppm, and the residual magnesium amount introduced from the flocculant was 6500 ppm.
[0258]
  (Preparation of Comparative Toner Particles 2)
  Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the preparation of the toner particles 1 except that 59.0 g of the following compound (107) was used instead of the compound (101). The resulting colored particles are referred to as “Comparative Toner Particles 2”. The surfactant residual amount of “Comparative Toner Particle 2” is53ppmThe amount of residual magnesium introduced from the flocculant was 8400 ppm.
[0259]
Compound (107): C₁₂H_{twenty five}(O (CH₂)_Ten)₂OSO_ThreeNa
(Preparation of comparative toner particles 3)
Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the preparation of the toner particles 1 except that 59.0 g of the compound (108) was used instead of the compound (101). The resulting colored particles are referred to as “Comparative Toner Particles 3”. The amount of residual surfactant in “Comparative Toner Particle 3” was 48 ppm, and the amount of residual magnesium introduced from the flocculant was 6340 ppm.
[0260]
Compound (108): C_TenH_{twenty one}(OCH₂CH₂)₁₂OSO_ThreeNa
(Preparation of toner particles 4 for comparison)
Colored particles having a number average particle diameter of 5.7 μm were obtained in the same manner as in the preparation of the toner particles 1 except that 59.0 g of the compound (109) was used instead of the compound (101). The resulting colored particles are referred to as “Comparative Toner Particles 4”. The surfactant residual amount of “Comparative Toner Particle 4” was 46 ppm, and the residual magnesium amount introduced from the flocculant was 8050 ppm.
[0261]
Compound (109): C₂₈H₅₇(OCH₂CH₂)₂OSO_ThreeNa
Tables 1 and 2 show physical properties and chemical properties of the obtained toner particles.
[0262]
[Table 1]

[0263]
[Table 2]

[0264]
In each of the toner particles 1 to 11 and the comparative toners 1 to 4 obtained as described above, hydrophobic silica (number average primary particle diameter 10 nm, hydrophobicity 63) is 1.0% by mass. At the same time, hydrophobic titanium oxide (number average primary particle size 25 nm, hydrophobization degree 60) was added at a ratio of 1.2% by mass and mixed by a Henschel mixer.
[0265]
The shape and particle size of these toner particles do not change depending on the addition of hydrophobic silica and hydrophobic titanium oxide.
[0266]
Each of the toner particles to which hydrophobic silica and hydrophobic titanium oxide were added and a ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin were mixed to prepare a developer having a toner concentration of 6% by mass. These developers are referred to as developers 1 to 11 (invention) and developers 12 to 15 (for comparison) corresponding to toner particles 1 to 11 and comparative toner particles 1 to 4, respectively.
[0267]
Each of the obtained developers was evaluated as follows.
<Evaluation of image density, fog, transfer rate, halftone uniformity>
Using a commercially available digital copying machine Konica Stios 7075 as an evaluation machine, a solid image and image density of black, a halftone image of 0.4, and a white background image are continuously obtained in a high temperature and humidity environment (33 ° C., 50% RH). After printing, the maximum image density of the solid image and the density of the “fog” on the white background were determined with a Macbeth reflection densitometer. “Transfer rate” is 60 mg / cm on the photoreceptor.²The amount of adhesion per unit area transferred to paper as a transfer agent was measured. If it is 80% or more, the uniformity of the image density is hard and good. The halftone homogeneity was determined visually. “◎” indicates that 15 or more of 20 people prefer, “○” indicates that 10 or more of 20 people prefer, “△” indicates that 5 or more of 20 people prefer. It was determined that less than 3 out of 20 people were judged as “x”. The number of sheets at the time when image smear “fogging” occurred and the number of sheets at the time when deposits on the photoreceptor occurred were recorded.
[0268]
<< Line width evaluation: Fine line reproducibility evaluation >>
The line width of the line image corresponding to the 2-dot line image signal was measured by a print evaluation system “RT2000” (manufactured by Yarman Co., Ltd.). If both the line width of the first formed image and the line width of the 200,000 formed image are 200 μm or less and the change in the line width is less than 10 μm, it can be said that fine line reproducibility is not a problem. .
[0269]
The characteristic evaluation results are shown in Table 3.
[0270]
[Table 3]

[0271]
From Table 3, it is clear that the sample of the present invention has a higher image density, lower fog, better transfer rate, better halftone uniformity, and better fine line reproducibility than the comparative sample. It is.
[0272]
【The invention's effect】
According to the present invention, an electrostatic charge image developing toner having high image density, low fog, good transfer rate and halftone homogeneity, and excellent fine line reproducibility, an image recording method using the same, An image forming method could be provided.
[Brief description of the drawings]
FIGS. 1A and 1B are explanatory views showing projected images of toner particles having no corners, and FIGS. 1B and 1C are explanatory views showing projected images of toner particles having corners, respectively.
FIG. 2 is a cross-sectional view showing an example of a fixing device used in the present invention.
[Explanation of symbols]
8 Recording materials
10 Heating roller
11 Core
12 Coating layer
13 Heating member
20 Pressure roll
21 Core
22 Coating layer
T Toner image formed on recording material

Claims (13)

A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of a surfactant represented by the following general formula (1). A toner for developing an electrostatic image, wherein the toner is produced through a process of depositing, aggregating and fusing.
General formula (1)
R ₁ (OR ₂ ) _n OSO ₃ M
[Wherein, R ₁ represents an alkyl group or arylalkyl group having 6 to 22 carbon atoms, and R ₂ represents an alkylene group having 2 to 6 carbon atoms. n represents an integer of 1 to 11, and M represents a monovalent metal element or ammonium ion. ]   A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of the surfactant represented by the general formula (1). A surfactant that is manufactured through a step of separating, agglomerating, and fusing, separating the resin particles from the aqueous medium, and drying the resin particles, and the resin particles are represented by the general formula (1) The toner for developing an electrostatic charge image according to claim 1, comprising 1 to 1000 ppm of the toner. A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of a surfactant represented by the following general formula (2). A toner for developing an electrostatic charge image, which is produced through a process of depositing, aggregating and fusing.
General formula (2)
R ₁ (OR ₂ ) _n SO ₃ M
[Wherein, R ₁ represents an alkyl group having 6 to 22 carbon atoms or an arylalkyl group, R ₂ represents an alkylene group having 2 to 6 carbon atoms, and n represents an integer of 1 to 11]. M represents a monovalent metal element or ammonium ion. ]   A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles, and the resin particles are salted in the aqueous medium in the presence of the surfactant represented by the general formula (2). A surfactant that is manufactured through a step of separating, agglomerating, and fusing, separating the resin particles from the aqueous medium, and drying the resin particles, and the resin particles are represented by the general formula (2) The toner for developing an electrostatic charge image according to claim 3, wherein 1 to 1000 ppm is contained.   A polymerizable monomer is polymerized in an aqueous medium to prepare a dispersion of resin particles. In the aqueous medium, the surfactant represented by the general formula (1) or the general formula (2) and a divalent compound are prepared. Alternatively, the resin particles are produced through a step of salting out, agglomerating and fusing the resin particles in the presence of a trivalent metal salt, and then a step of separating and drying the resin particles from the aqueous medium. 1 to 1000 ppm of the surfactant represented by the general formula (1) or the general formula (2), and a total of 250 to 20000 ppm of divalent or trivalent metal elements used as a flocculant. The toner for developing an electrostatic charge image according to any one of claims 1 to 4.   6. The electrostatic image developing toner according to claim 5, comprising a total of 350 to 35000 ppm of a divalent or trivalent metal element used as an aggregating agent and a monovalent metal element added as an aggregation terminator. The toner for developing an electrostatic charge image according to any one of claims 1 to 6, wherein the number of toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more. The electrostatic image developing toner according to claim 1, wherein the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more. 9. The electrostatic image developing toner according to claim 1, wherein the number of toner particles having no corners is 50% by number or more. The toner for developing an electrostatic charge image according to claim 1, wherein the toner has a number average particle diameter of 3 to 8 μm. When the particle diameter of the toner particles is D (μm), the histogram showing the particle size distribution on the basis of the natural logarithm lnD on the horizontal axis and classifying the horizontal axis at intervals of 0.23 is included in the most frequent class. The sum (M) of the relative frequency (m1) of the toner particles and the relative frequency (m2) of the toner particles contained in the next most frequent class is 70% or more. The toner for developing an electrostatic charge image according to any one of claims 1 to 10. In producing the toner for developing an electrostatic charge image according to any one of claims 1 to 11, a dispersion of resin particles is prepared by polymerizing a polymerizable monomer in an aqueous medium, and in the aqueous medium. A step of salting out, agglomerating and fusing the resin particles in the presence of the surfactant represented by the general formula (1) or the general formula (2) and the divalent metal salt or the trivalent metal salt; A method for producing a toner for developing an electrostatic charge image, comprising a step of separating and drying the resin particles from the aqueous medium. A step of forming an electrostatic charge image on the electrostatic charge image carrier, a step of developing the electrostatic charge image with a developer containing toner for developing an electrostatic charge image to form a toner image, and the toner image on the transfer member. In the image forming method including the transferring step, the electrostatic charge image developing toner according to any one of claims 1 to 11 is used as the electrostatic charge image developing toner.

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