JP3919540B2 - Dry toner and image forming apparatus - Google Patents

Description

【００４１】
本発明に用いられる荷電制御剤は、結着樹脂１００質量部に対して２〜１０質量部含有させることにより、トナー粒子が逆電荷を保持しにくくなり、帯電状態を一層良好なものとすることができる。
【００４２】
本発明の乾式トナーは、トナーの粒子形状が上記条件を満足するようにトナーの粒子形状を精密に制御することにより、各トナー粒子に同一含有量のキナクリドン顔料と溶性アゾ顔料が内包化されるため、キナクリドン顔料と溶性アゾ顔料による帯電特性の影響も均一なものになり、これによって、現像性と転写性とがバランス良く改善される。
【００４３】
即ち、本発明の乾式トナーは、トナーの円相当個数平均径Ｄ１（μｍ）を２〜１０μｍと小粒径化することにより、画像の輪郭部分、特に文字画像やラインパターンの現像での再現性が良好なものとなる。
【００４４】
また、本発明の乾式トナーは、トナーの円形度頻度分布の平均円形度を０．９４０〜０．９９５、好ましくは０．９５５〜０．９９５、より好ましくは０．９７０〜０．９９０とすることにより、従来では困難であった小粒径を呈するトナーの転写性が大幅に改善される。
【００４５】
さらに、本発明の乾式トナーは、トナーの円形度頻度分布の円形度標準偏差を０．０４０未満、好ましくは０．０３５未満、より好ましくは０．０１５以上０．０３５未満とすることにより、現像性に関する問題を大幅に改善することができる。
【００４６】
また、本発明の乾式トナーは、円形度頻度分布の平均円形度が０．９５５未満のトナーを１５％以下にすることで、画像形成における現像効率が十分なレベルとなり画像形成も良好なものとなる。
【００４７】
なお、トナーの粒径についてはトナー粒子の製造法及び製造条件やトナーの分級、及び分級品の混合によって調整することができ、トナーの粒子形状については、トナー粒子の製造法及びその製造条件や機械的衝撃法による球形化処理によって調整することができる。
【００４８】
本発明におけるトナーの円相当径、円形度、及びそれらの頻度分布とは、トナー粒子の形状を定量的に表現する簡便な方法として用いたものであり、本発明では、フロー式粒子像測定装置、例えば「ＦＰＩＡ−１０００型」（東亜医用電子社製）、を用いて測定し、下式を用いて算出される。
【００４９】
【数２】

【数３】

【００５０】
ここで、「粒子投影面積」とは二値化されたトナー粒子像の面積であり、「粒子投影像の周囲長」とは該トナー粒子像のエッジ点を結んで得られる輪郭線の長さと定義する。
【００５１】
本発明における円形度はトナー粒子の凹凸の度合いを示す指標であり、トナー粒子が完全な球形の場合には１．０００を示し、表面形状が複雑になる程、円形度は小さな値となる。
【００５２】
本発明において、トナーの個数基準における粒径頻度分布の平均値を意味する円相当個数平均径Ｄ１（μｍ）と粒径標準偏差ＳＤｄは、粒度分布の分割点ｉでの粒径（中心値）をｄｉ、頻度をｆｉとすると次式から算出される。
【００５３】
【数４】

【数５】

【００５４】
また、円形度頻度分布の平均値を意味する平均円形度Ｃと円形度標準偏差ＳＤｃは、粒度分布の分割点ｉでの円形度（中心値）をｃｉ、頻度をｆｃｉとすると、次式から算出される。
【００５５】
【数６】

【数７】

【００５６】
本発明に係るキナクリドン顔料としては、下記一般式［１］で示される顔料が挙げられ、これらを単独、若しくは併用して用いることができる。
【００５７】
【化４】

【００５８】
これらの中でも、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ２０２、及びＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｖｉｏｌｅｔ １９（それぞれカラーインデックス第４版記載の名称による）が、色相や耐光性といった物理的安定性の観点から好ましく用いられる。
【００５９】
一方、本発明に係る溶性アゾ顔料とは、親水性基をもつ水溶性又は難水溶性アゾ染料を、例えばＣａ、Ｂａ、Ｓｒ、Ｍｎ等の金属で塩を形成させて、不溶性化したアゾレーキ顔料を言い、このような溶性アゾ顔料としては、下記一般式［２］で示される顔料が挙げられ、これらを単独、若しくは併用して用いることができる。
【００６０】
【化５】

【００６１】
上記溶性アゾ顔料としては、例えば、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：３、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：４、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：５、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５２：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５２：２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５７：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５８：２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５８：４、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ６４、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ６４：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ２００、及びＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｒｏｗｎ ５（それぞれカラーインデックス第４版記載の名称による）等が挙げられるが、特に、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５７：１が上記キナクリドン顔料の再凝集抑制による分散性の改善、さらには発色性、色調、及び帯電特性の向上等の点から好ましく用いられる。
【００６２】
本発明の乾式トナーにおいて、トナー粒子中のキナクリドン顔料と溶性アゾ顔料の総含有量は１〜２０質量％、好ましくは３〜１０質量％であって、かつ、両者の含有量の質量比率は、キナクリドン顔料：溶性アゾ顔料＝１０：９０〜５０：５０を満足するように配合される。
【００６３】
トナー粒子中のキナクリドン顔料と溶性アゾ顔料の総含有量が１質量％未満の場合は、着色剤としての機能を十分に果たすことができないことがある。また、２０質量％を超える場合には、トナー粒子中での着色剤の存在状態が過剰となり、キナクリドン顔料と溶性アゾ顔料の共存効果が消失し、着色剤の再凝集が進行するため、透明性、帯電特性、及び定着性に悪影響を及ぼすことがある。
【００６４】
また、キナクリドン顔料と溶性アゾ顔料の含有量の質量比率が、キナクリドン顔料：溶性アゾ顔料＝１０：９０〜５０：５０の範囲外である場合には、共存効果が消失するばかりか、溶性アゾ顔料の含有比率が５０質量％未満の場合には十分な着色力が得られないことに加え、過剰なキナクリドン顔料が引き起こす感光体の損傷あるいは感光体への固着、定着不良を引き起こすことがあり、９０質量％を超える場合には耐光性の低下の他、過剰な溶性アゾ顔料が引き起こす感光体の汚染あるいは感光体上への固着等の問題を生じることがある。
【００６５】
なお、本発明の乾式トナーは、着色剤としてキナクリドン顔料と溶性アゾ顔料を必須とするものであって、他の顔料や染料等の他の着色剤をさらに含むものであってもよい。
【００６６】
また、本発明に係るキナクリドン顔料、溶性アゾ顔料は、従来公知の方法により、その表面を処理することができる。表面処理された着色剤を用いることにより、着色剤の再凝集を防止し、トナー粒子中での着色剤の分散性が向上し、さらにはトナーの帯電性を好ましい状態にすることができるので、上記の如き特性を一層改善させることができる。
【００６７】
本発明に係るキナクリドン顔料、溶性アゾ顔料を好ましく処理できる表面処理剤としては、ポリエチレンワックス、ポリプロピレンワックス、天然ロジン（トール油ロジン、ガムロジン、ロッドロジンなど）、天然ロジンから抽出して得られる精製ロジン（アビエチン酸など）、変性ロジン（水添ロジン、不均化ロジン、重合ロジンなど）、合成ロジン（スチレンアクリルロジン酸など）等のロジン化合物、及び、上記ロジン化合物のアルカリ金属塩やエステル化合物等を挙げることができる。
【００６８】
本発明に用いるワックス成分は、「ＡＳＴＭ Ｄ３４１８−８２」に準じて測定されたＤＳＣ曲線における主体吸熱ピーク温度（融点）が４０〜１３０℃である。ワックス成分の融点が上記の範囲であると、定着性、透明性、さらには着色力を良好にすることができる。
【００６９】
本発明において使用し得るワックス成分としては、具体的には、パラフィンワックス、マイクロクリスタリンワックス、ペトロラタムの如き石油系ワックス及びその誘導体、モンタンワックス及びその誘導体、フィッシャートロプシュ法による炭化水素ワックス及びその誘導体、ポリエチレンに代表されるポリオレフィンワックス及びその誘導体、カルナバワックス、キャンデリラワックスの如き天然ワックス及びそれらの誘導体等が挙げられ、誘導体には酸化物や、ビニルモノマーとのブロック共重合物、グラフト変性物も含まれる。また、高級脂肪族アルコールの如きアルコール；ステアリン酸、パルミチン酸の如き脂肪族あるいはその化合物；酸アミド、エステル、ケトン、硬化ヒマシ油及びその誘導体、植物ワックス、動物ワックスが挙げられる。これらは単独、若しくは併せて用いることができる。
【００７０】
特に、パラフィンワックスの如き低融点ワックスと、フィッシャートロプシュ法による炭化水素ワックスの如き高融点ワックスを併用すると、定着性や着色力をさらに改善でき、なお好ましい。
【００７１】
本発明の乾式トナーは、該ワックス成分を結着樹脂１００質量部に対して１〜３０質量部、より好ましくは３〜２０質量部含有することで、良好な定着性をもたらすことができる。
【００７２】
本発明に係る乾式トナーを製造する方法としては、結着樹脂、本発明に係る着色剤、ワックス成分等を加圧ニーダー等により溶融混練した後、冷却した混練物を所望のトナー粒径に微粉砕し、さらに微粉砕物を分級して粒度分布を調整して乾式トナーにする粉砕法；特公昭３６−１０２３１号公報、特開昭５９−５３８５６号公報及び特開昭５９−６１８４２号公報に記載されている懸濁重合法を用いて直接トナー粒子を製造する方法；特公昭５６−１３９４５号公報等に記載のディスク又は多流体ノズルを用いて溶融混練物を空気中に霧化して球状トナー粒子を製造する方法；及びソープフリー重合法に代表される乳化重合法等、公知の方法を用いることが可能であるが、上記条件を満足するようなトナーの粒子形状を精密に制御するには、懸濁重合法により製造されることが望ましい。
【００７３】
上記の如きトナー平均円形度、円形度標準偏差及び円形度０．９５０未満のトナー個数についての制御は、懸濁重合法によるトナー粒子の製造方法において、造粒工程から重合工程に至る重合反応時の、水系分散媒体のｐＨによって可能である。
【００７４】
懸濁重合法により製造されるトナー粒子は、重合によって結着樹脂を形成する重合性単量体、本発明に係る着色剤、極性樹脂、ワックス成分、荷電制御剤、及び重合開始剤を混合して重合性単量体組成物を調製し、重合性単量体組成物を水系媒体中へ分散して重合性単量体組成物の粒子を生成し、水系媒体中で重合性単量体組成物の粒子中の重合性単量体を重合して生成される。
【００７５】
本発明に用いられるトナー粒子の結着樹脂としては、一般的に用いられているスチレン−（メタ）アクリル共重合体、ポリエステル樹脂、エポキシ樹脂、スチレン−ブタジエン共重合体が挙げられる。重合法により直接トナー粒子を得る方法においては、それらを形成するための単量体が用いられる。
【００７６】
このような重合性単量体として具体的にはスチレン；ｏ−（ｍ−，ｐ−）メチルスチレン、ｍ−（ｐ−）エチルスチレンの如きスチレン系単量体；（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、アクリル酸プロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸オクチル、（メタ）アクリル酸ドデシル、（メタ）アクリル酸ステアリル、（メタ）アクリル酸ベヘニル、（メタ）アクリル酸２−エチルヘキシル、（メタ）アクリル酸ジメチルアミノエチル、（メタ）アクリル酸ジエチルアミノエチルの如き（メタ）アクリル酸エステル系単量体；ブタジエン、イソプレン、シクロヘキセン、（メタ）アクリロニトリル、アクリル酸アミドの如きエン系単量体が好ましく用いられる。
【００７７】
これらは、単独、又は、一般的には出版物ポリマーハンドブック第２版III−ｐ１３９〜１９２（Ｊｏｈｎ Ｗｉｌｅｙ＆Ｓｏｎｓ社製）に記載の理論ガラス転移温度（Ｔｇ）が４０〜７５℃を示すように単量体を適宜混合して用いられる。理論ガラス転移温度が４０℃未満の場合にはトナーの保存安定性や耐久安定性の面から問題が生じやすく、一方７５℃を超える場合はトナーのフルカラー画像形成の場合において、ＯＨＰ画像の透明性が低下することがある。
【００７８】
本発明において、上述の結着樹脂と共にポリエステル樹脂やポリカーボネート樹脂等の極性樹脂を併用することができる。
【００７９】
例えば、懸濁重合法等により直接トナー粒子を製造する場合には、分散工程から重合工程に至る重合反応時に極性樹脂を添加すると、トナー粒子となる重合性単量体組成物と水系分散媒体の呈する極性のバランスに応じて、添加した極性樹脂がトナー粒子の表面に薄層を形成したり、トナー粒子表面から中心に向け傾斜性をもって存在するように制御することができる。この時、本発明に係る着色剤やジアルキルサリチル酸及び含硫黄重合体と相互作用を有するような極性樹脂を用いることによって、トナー粒子中への該着色剤の存在状態を望ましい形態にすることが可能である。
【００８０】
上記極性樹脂の添加量は、結着樹脂１００質量部に対して１〜２５質量部使用するのが好ましく、より好ましくは２〜１５質量部である。１質量部未満ではトナー粒子中での極性樹脂の存在状態が不均一となりやすく、逆に２５質量部を超えるとトナー粒子表面に形成される極性樹脂の薄層が厚くなるため、好ましくない。
【００８１】
本発明に用いられる極性樹脂としては、具体的には、ポリエステル樹脂、エポキシ樹脂、スチレン−アクリル酸共重合体、スチレン−メタクリル酸共重合体、スチレン−マレイン酸共重合体が挙げられる。特にピーク分子量が３０００〜１０，０００のポリエステル樹脂がトナー粒子の流動性、負摩擦帯電特性、透明性を良好にすることができるので好ましい。
【００８２】
さらに、本発明においては、トナー粒子の機械的強度を高めると共に、トナー粒子の分子量を制御するために、結着樹脂の合成時に架橋剤を用いることが好ましい。
【００８３】
本発明の乾式トナーに用いられる架橋剤としては、二官能の架橋剤として、ジビニルベンゼン、ビス（４−アクリロキシポリエトキシフェニル）プロパン、エチレングリコールジアクリレート、１，３−ブチレングリコールジアクリレート、１，４−ブタンジオールジアクリレート、１，５−ペンタンジオールジアクリレート、１，６−ヘキサンジオールジアクリレート、ネオペンチルグリコールジアクリレート、ジエチレングリコールジアクリレート、トリエチレングリコールジアクリレート、テトラエチレングリコールジアクリレート、ポリエチレングリコール＃２００、＃４００、＃６００の各ジアクリレート、ジプロピレングリコールジアクリレート、ポリプロピレングリコールジアクリレート、ポリエステル型ジアクリレート（ＭＡＮＤＡ日本化薬）、及び上記のジアクリレートをジメタクリレートに代えたものが挙げられる。
【００８４】
多官能の架橋剤としては、ペンタエリスリトールトリアクリレート、トリメチロールエタントリアクリレート、トリメチロールプロパントリアクリレート、テトラメチロールメタンテトラアクリレート、オリゴエステルアクリレート及びそのメタクリレート、２，２−ビス（４−メタクリロキシ、ポリエトキシフェニル）プロパン、ジアリルフタレート、トリアリルシアヌレート、トリアリルイソシアヌレート及びトリアリルトリメリテートが挙げられる。
【００８５】
これらの架橋剤は、前記重合性単量体１００質量部に対して、好ましくは０．０５〜１０質量部、より好ましくは０．１〜５質量部用いることが良い。
【００８６】
本発明の乾式トナーを懸濁重合法により製造する場合、重合開始剤としては、具体的には、２，２’−アゾビス−（２，４−ジメチルバレロニトリル）、２，２’−アゾビスイソブチロニトリル、１，１’−アゾビス（シクロヘキサン−１−カルボニトリル）、２，２’−アゾビス−４−メトキシ−２，４−ジメチルバレロニトリル、アゾビスイソブチロニトリルの如きアゾ系又はジアゾ系重合開始剤；ベンゾイルペルオキシド、メチルエチルケトンペルオキシド、ジイソプロピルペルオキシカーボネート、クメンヒドロペルオキシド、２，４−ジクロロベンゾイルペルオキシド、ラウロイルペルオキシドの如き過酸化物系重合開始剤が用いられる。
【００８７】
これらの重合開始剤の使用量は、目的とする重合度により変化するが、一般的には、重合性ビニル系単量体１００質量部に対して５〜２０質量部が用いられる。重合開始剤の種類は、重合法により若干異なるが、１０時間半減期温度を参考に、単独又は混合して使用される。
【００８８】
本発明の乾式トナーを懸濁重合法により製造する場合、水系分散媒体調製時に使用する分散剤としては、公知の無機系及び有機系の分散剤を用いることができる。
【００８９】
具体的には、無機系の分散剤としては、例えば、リン酸三カルシウム、リン酸マグネシウム、リン酸アルミニウム、リン酸亜鉛、炭酸マグネシウム、炭酸カルシウム、水酸化カルシウム、水酸化マグネシウム、水酸化アルミニウム、メタケイ酸カルシウム、硫酸カルシウム、硫酸バリウム、ベントナイト、シリカ、アルミナが挙げられる。
【００９０】
また、有機系の分散剤としては、例えば、ポリビニルアルコール、ゼラチン、メチルセルロース、メチルヒドロキシプロピルセルロース、エチルセルロース、カルボキシメチルセルロースのナトリウム塩、デンプンが挙げられる。
【００９１】
また、市販のノニオン、アニオン、カチオン型の界面活性剤の利用も可能である。例えば、ドデシル硫酸ナトリウム、テトラデシル硫酸ナトリウム、ペンタデシル硫酸ナトリウム、オクチル硫酸ナトリウム、オレイン酸ナトリウム、ラウリル酸ナトリウム、ステアリン酸カリウム、オレイン酸カルシウムを用いることができる。
【００９２】
本発明の乾式トナーを懸濁重合法により製造する場合、水系分散媒体調製時に使用する分散剤としては、無機系の難水溶性の分散剤が好ましく、しかも酸に可溶性である難水溶性無機分散剤を用いるとよい。また、本発明においては、難水溶性無機分散剤を用い、水系分散媒体を調製する場合に、これらの分散剤が重合性ビニル系単量体１００質量部に対して、０．２〜２．０質量部となるような割合で使用することが好ましい。また、本発明においては、重合性単量体組成物１００質量部に対して３００〜３，０００質量部の水を用いて水系分散媒体を調製することが好ましい。
【００９３】
本発明において、上記したような難水溶性無機分散剤が分散された水系分散媒体を調製する場合には、市販の分散剤をそのまま用いて分散させてもよいが、細かい均一な粒度を有する分散剤粒子を得るために、水等の液媒体中で、高速撹拌下、上記したような難水溶性無機分散剤を生成させて調製してもよい。例えば、リン酸三カルシウムを分散剤として使用する場合、高速撹拌下でリン酸ナトリウム水溶液と塩化カルシウム水溶液を混合してリン酸三カルシウムの微粒子を形成することで、好ましい分散剤を得ることができる。
【００９４】
本発明の乾式トナーは、主に一成分現像剤として用いられるが、本発明の乾式トナーとキャリアとを混合して二成分現像剤として用いることも可能である。本発明のトナーは、その目的に合わせて種々の添加剤をさらに含むものであっても良く、このような添加剤としては、例えば、主にトナー粒子の流動性を向上させる目的で配合される疎水性表面処理シリカ微粒子等の無機微粉体や、主にトナー粒子の帯電性を制御する目的で配合される導電性金属酸化物微粒子等の導電性微粒子などが挙げられ、このような添加物には公知のものを用いることができる。
【００９５】
なお、本発明の乾式トナーは、フルカラー画像形成時に用いられるマゼンタトナーに適している。
【００９６】
本発明の画像形成装置は、像担持体と、像担持体を帯電させる帯電手段と、帯電した像担持体に静電潜像を形成する静電潜像形成手段と、像担持体に形成された静電潜像を現像剤によって現像してトナー像を形成する現像手段と、形成されたトナー像を像担持体から転写材に転写する転写手段と、転写材上の未定着トナー像を転写材に定着させる定着手段とを有し、本発明の乾式トナーを現像剤として用いる。
【００９７】
本発明の画像形成装置は、本発明の乾式トナーの種類、例えば一成分現像剤、又は二成分現像剤、に応じて、本発明の乾式トナーを適用できる構成であれば特に限定されず、公知の手段や部材などによって構成することができる。本発明の画像形成装置は、本発明の乾式トナーをマゼンタトナーとするフルカラー画像形成装置に好ましくは適用される。
【００９８】
【実施例】
以下、具体的実施例によって本発明を説明するが、本発明はなんらこれらに限定されるものではない。
【００９９】
（トナーの製造例１）
高速撹拌装置ＴＫ式ホモミキサー（特殊機化工業社製）を具備した２リットル用４つ口フラスコ中に、イオン交換水７００質量部と０．１ｍｏｌ／リットル−Ｎａ₃ＰＯ₄水溶液８００質量部を投入し、高速撹拌装置の回転数を１２０００ｒｐｍに設定し、６５℃に加温せしめた。ここに１．０ｍｏｌ／リットル−ＣａＣｌ₂水溶液７０質量部を添加し、微小な難水溶性分散安定剤Ｃａ₃(ＰＯ₄)₂を含む水系分散媒体を調製した。
【０１００】
一方、

からなる混合物をＴ．Ｋ．ホモディスパー（特殊機化工業社製）を用い１時間分散し、顔料分散組成物を調製した。
【０１０１】
さらに、別容器にて、
・スチレン単量体 ３０質量部
・２−エチルヘキシルアクリレート単量体 ２３質量部
・ジビニルベンゼン単量体 ０．３質量部
・エステルワックス（融点＝５０℃） ４質量部
・ポリエチレンワックス（融点＝１２０℃） ５質量部
からなる混合物に前記顔料分散組成物６３質量部を添加し、６５℃に加温しながら分散、溶解せしめた後、２，２’−アゾビス（２，４−ジメチルバレロニトリル）５質量部を添加し、分散質としての重合性ビニル系単量体組成物を調製した。
【０１０２】
次に、前記水系分散媒体中に該重合性単量体組成物を投入し、内温６５℃のＮ₂雰囲気下で、高速撹拌装置の回転数を１５０００ｒｐｍに維持しつつ、５分間撹拌し、該重合性単量体組成物を造粒した。その後、撹拌装置をパドル撹拌羽根を具備したものに換え、２００ｒｐｍで撹拌しながら同温度に保持し、重合性ビニル系単量体の重合転化率がほぼ１００％になったところで重合反応を完了した。
【０１０３】
重合終了後、加熱減圧下で残存モノマーを留去し、次いで、冷却後に希塩酸を添加して難水溶性分散剤を溶解せしめた。さらに水洗浄を数回繰り返した後、円錘型リボン乾燥機（大川原製作所製）を用い、乾燥処理を行い、重合体粒子（Ａ）を得た。
【０１０４】
上記重合体粒子（Ａ）１００質量部とシリコーンオイル処理シリカ微粉体（ＢＥＴ；２００ｍ²／ｇ）１．５質量部をヘンシェルミキサー（三井金属社製）で乾式混合して、トナー（Ａ）とした。
【０１０５】
該トナー（Ａ）の円相当個数平均径は５．７μｍで、円形度頻度分布における平均円形度は０．９８７、円形度標準偏差は０．０２７で、円形度０．９５０未満のトナー粒子数は５．４個数％であった。
【０１０６】
（トナーの製造例２〜５）
キナクリドン顔料と溶性アゾ顔料、溶性アゾ顔料の処理剤の種類と添加量、荷電制御剤の種類と添加量、及びワックス成分の種類と添加量を変更する以外は、前記トナーの製造例１と同様にして、重合体粒子（Ｂ）〜（Ｅ）を得た後、トナー（Ｂ）〜（Ｅ）を調製した。
【０１０７】
（トナーの製造例６）
下記材料を予め混合し、二軸エクストルーダーで溶融混練し、冷却した混練物をハンマーミルで粗粉砕し、粗粉砕物をジェットミルで微粉砕し、得られた微粉砕物を分級して分級粉（Ｆ）とした。
・結着樹脂 １００質量部
［スチレン−２−エチルヘキシルアクリレート−ジビニルベンゼン共重合体ピーク分子量＝１．６万、Ｍｗ／Ｍｎ＝５．０、Ｔｇ＝６０℃］
・キナクリドン顔料 ３質量部
（Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２）
・溶性アゾ顔料 ３．５質量部
（Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：１）
・荷電制御剤 ３質量部
（ジアルキルサリチル酸のアルミニウム化合物）
・パラフィンワックス（融点＝６５℃） １０質量部
【０１０８】
上記分級粉（Ｆ）を用い、前記トナーの製造例１と同様にして、トナー（Ｆ）を調製した。
【０１０９】
（比較用トナーの製造例１）
着色剤として「Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２」７質量部のみ、荷電制御剤としてベンジル酸のホウ素化合物２部、ワックス成分としてエステルワックス（融点＝６０℃）１０部を用いることに変更する以外は、前記トナーの製造例１と同様にして比較用重合体粒子（ａ）を得た後、比較用トナー（ａ）を調製した。
【０１１０】
（比較用トナーの製造例２）
着色剤として「Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５７：１」５質量部のみ、荷電制御剤としてベンジル酸のホウ素化合物２部、ワックス成分としてエステルワックス（融点＝６０℃）１０部を用いることに変更する以外は、前記トナーの製造例１と同様にして比較用重合体粒子（ｂ）を得た後、比較用トナー（ｂ）を調製した。
【０１１１】
（比較用トナーの製造例３）
着色剤として「Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １７６」５質量部、荷電制御剤としてジアルキルサリチル酸のアルミニウム化合物１部、ワックス成分としてエステルワックス（融点＝６０℃）１０部を用いることに変更する以外は、前記トナーの製造例１と同様にして比較用重合体粒子（ｃ）を得た後、比較用トナー（ｃ）を調製した。
【０１１２】
（比較用トナーの製造例４）
キナクリドン顔料と溶性アゾ顔料の種類と添加量、荷電制御剤としてカリックスアレーン３部を用いること、及びワックス成分の添加量を変更する以外は、前記トナーの製造例６と同様にして分級品（ｄ）を得た後、比較用トナー（ｄ）を調製した。
【０１１３】
（比較用トナーの製造例５）
キナクリドン顔料と溶性アゾ顔料の種類と添加量、荷電制御剤としてカリックスアレーン２部、ワックス成分を添加しないことに変更する以外は、前記トナーの製造例６と同様にして分級品（ｅ）を得た後、比較用トナー（ｅ）を調製した。
【０１１４】
上記トナーの製造例及び比較用トナーの製造例の主な処方内容、及びトナーの粒子形状について、表１及び表２にまとめた。
【０１１５】
（トナーの製造例７）
着色剤として「Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ １５：３」５質量部、ワックス成分としてエステルワックス（融点＝６０℃）１０部を用いることに変更する以外は、前記トナーの製造例１と同様にして重合体粒子を得た後、シアントナーを調製した。
【０１１６】
（トナーの製造例８）
着色剤として「Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ９３」７質量部、ワックス成分としてエステルワックス（融点＝６０℃）１０部を用いることに変更する以外は、前記トナーの製造例１と同様にして重合体粒子を得た後、イエロートナーを調製した。
【０１１７】
（実施例１）
帯電安定性について、製造例１で得られたトナー（Ａ）の摩擦帯電量を常温常湿下、高温高湿下で測定したところ、有意差は見られず、トナー（Ａ）は環境帯電安定性に優れていた。
【０１１８】
画像形成装置として、レーザービームプリンター（キヤノン製：ＬＢＰ−２１６０）を改造して用いた。この画像形成装置のプロセスカートリッジに、トナーの製造例１で得られたトナー（Ａ）を投入し、転写材として複写機用普通紙（７５ｇ／ｍ²）を用い、単色モードにて印字面積比率４％の文字画像を２８枚（Ａ４サイズ）／分のプリントアウト速度で１０，０００枚分をプリントアウトした後、プリントアウト画像を評価したところ、プリント初期と同等で良好の画像が得られた。これについて、感光体表面の観察を行ったところ、感光体表面のフィルミング、残留トナーの固着、及び損傷は発生しておらず、非常に良好な状態であった。また、画像剥がれの発生も見られなかった。
【０１１９】
さらに、０．１ｍｇ／ｃｍ²から１．０ｍｇ／ｃｍ²の範囲で、転写紙上のトナー量の異なる数種類のベタ画像を作成し、転写紙上のトナー量と画像濃度の関係を評価したところ、転写紙上のトナー量が比較的少量であっても十分な画像濃度の画像が得られ、着色力の高さが確認できた。
【０１２０】
また、転写紙上のトナー量が０．６ｍｇ／ｃｍ²程度のベタ画像を作成し、画像耐光性を評価したところ、優れた耐光性を示した。
【０１２１】
マゼンタトナー（Ａ）に加え、トナーの製造例７で得られたシアントナーとトナーの製造例８で得られたイエロートナーを用い、上記と同様にして、複写機用普通紙（７５ｇ／ｍ²）にフルカラー画像をプリントアウトしたところ、２次色以上の重ね合わせにおいても良好であり、色再現性の優れた画像が得られた。また、ＯＨＰシート「ＣＧ３７００」（３Ｍ社製）上にプリントアウトしＯＨＰ投影画像を評価したところ、透明性に優れ、さらに２次色以上の重ね合わせにおいても良好であり、色空間が広く優れた投影画像が得られた。
【０１２２】
これらの評価結果を表４にまとめて示した。
なお、評価方法及びその評価基準は次の通りであり、後述の実施例２〜６及び比較実施例１〜５もこれらに従っている。
【０１２３】
（評価方法）
（１）トナーの環境帯電安定性
図１はトナーの摩擦帯電量を測定する装置の概略的説明図である。トナー（外添剤なし）とキャリアの混合物を５０〜１００ｍｌ容量のポリエチレン製のビンに入れ、５００回手で振とうして摩擦帯電させる。該キャリアはシリコーン樹脂コートされたフェライトキャリア（平均粒径３５μｍ）を使用し、トナーとキャリアの混合重量比は７：９３とする。
【０１２４】
底に５００メッシュのスクリーン３のある金属製の測定容器２に、該混合物（トナーとキャリア）Ｗ₀（ｇ：約０．５〜１．５ｇ）を入れ金属製のふた４をする。このときの測定容器２全体の重量を秤りＷ₁（ｇ）とする。次に吸引機１（測定容器２と接する部分は少なくとも絶縁性）において、吸引口７から吸引し風量調節弁６を調整して真空計５の圧力を２４５０（ｈｐａ）とする。この状態で２分間吸引を行いトナーを吸引除去する。このときのトナーの摩擦帯電量Ｑ（ｍＣ／ｋｇ）は、トナー１００％補正をすると下記のように定義される。
【０１２５】
【数８】

【０１２６】
トナーの環境帯電安定性は、該トナーの摩擦帯電量Ｑを常温常湿（２３℃、６０％ＲＨ）、高温高湿（３５℃、９０％ＲＨ）で測定した。
【０１２７】
＜摩擦帯電量Ｑ（常温常湿）＞
Ａ：−３５ｍＣ／ｋｇ未満
Ｂ：−３５ｍＣ／ｋｇ以上、−３０ｍＣ／ｋｇ未満
Ｃ：−３０ｍＣ／ｋｇ以上、−２５ｍＣ／ｋｇ未満
Ｄ：−２５ｍＣ／ｋｇ以上
【０１２８】
＜摩擦帯電量Ｑ（高温高湿）＞
Ａ：常温常湿の摩擦帯電量Ｑとの差が、５未満
Ｂ：常温常湿の摩擦帯電量Ｑとの差が、５以上、１０未満
Ｃ：常温常湿の摩擦帯電量Ｑとの差が、１０以上、１５未満
Ｄ：常温常湿の摩擦帯電量Ｑとの差が、１５以上
【０１２９】
（２）感光体とのマッチング
感光体表面のフィルミング、残留トナーの固着、及び損傷の発生状況とプリントアウト画像への影響を目視で評価した。
Ａ：非常に良好（未発生）
Ｂ：良好（わずかに傷の発生が見られるが、画像への影響はない）
Ｃ：普通（固着や傷があるが、画像への影響が少ない）
Ｄ：悪い（固着が多く、縦スジ状の画像欠陥を生じる）
【０１３０】
（３）画像剥がれ
やや厚めの転写紙（１０５ｇ／ｍ²、Ａ４サイズ）上にトナー量が０．８ｍｇ／ｃｍ²程度となるようにベタ画像を作成し、得られた画像表面の画像剥がれの発生状況を目視により評価した。画像剥がれの箇所が少ない程、発生が抑制されたことになる。
Ａ：未発生
Ｂ：１箇所以上、５箇所以下
Ｃ：６箇所以上、１０箇所以下
Ｄ：１１箇所以上（あるいは、直径２ｍｍ以上の画像剥がれが発生）
【０１３１】
（４）着色力
０．１ｍｇ／ｃｍ²から１．０ｍｇ／ｃｍ²の範囲で転写紙上にトナー量の異なる数種類のベタ画像を作成し、それらの画像濃度を「Ｘ−Ｒｉｔｅ ５０４」を用いて測定し、転写紙上のトナー量と画像濃度の関係を求めた後、特に転写紙上のトナー量が０．５ｍｇ／ｃｍ²の場合に対応する画像濃度をもって相対的に着色力を評価した。
Ａ：転写紙上のトナー量が０．５ｍｇ／ｃｍ²で、画像濃度が１．４以上
Ｂ：転写紙上のトナー量が０．５ｍｇ／ｃｍ²で、画像濃度が１．３５以上、１．４０未満
Ｃ：転写紙上のトナー量が０．５ｍｇ／ｃｍ²で、画像濃度が１．２０以上、１．３５未満
Ｄ：転写紙上のトナー量が０．５ｍｇ／ｃｍ²で、画像濃度が１．２０未満
【０１３２】
（５）画像耐光性
転写紙上のトナー量が０．６ｍｇ／ｃｍ²程度のベタ画像を作成し、カーボンアークランプを光源とした紫外線オートフェードメーター「ＦＡＬ−ＡＵ」（スガ試験機社製）を用い、「ＪＩＳ Ｋ ７１０２」に準じて評価した。最大照射時間を２４０時間とし、光照射前後の画像濃度の維持率を算出し、画像の耐光性を評価した。画像濃度維持率（％）が１００％に近い程、画像耐光性に優れることになる。
Ａ：９０％以上
Ｂ：８０％以上、９０％未満
Ｃ：７０％以上、８０％未満
Ｄ：７０％未満
【０１３３】
（６）普通紙上色再現性
複写機用普通紙（７５ｇ／ｍ²）上のフルカラー画像を目視評価すると共に、「Ｘ−Ｒｉｔｅ ＳＰ６８」（Ｘ−Ｒｉｔｅ社製）にて測定し、国際照明委員会で規格されたＬ^*ａ^*ｂ^*表色系の明度Ｌ^*、赤又は緑の度合いを表すａ^*、黄又は青の度合いを表すｂ^*で決定される色空間立体の体積を求めた。数値が大きいほど色空間が広く、小さいほど色再現性が乏しいことを意味する。
【０１３４】
＜色空間体積＞
Ａ：２５０万以上
Ｂ：２００万以上２５０万未満
Ｃ：１５０万以上２００万未満
Ｄ：１５０万未満
【０１３５】
＜目視評価＞
Ａ：マゼンタ、２次色（赤色、青色）いずれの色再現性も優れる
Ｂ：マゼンタの色再現性は優れるが、２次色（赤色、青色）はやや劣る
Ｃ：マゼンタ、２次色（赤色、青色）いずれの色再現性もやや劣る
Ｄ：マゼンタ、２次色（赤色、青色）いずれの色再現性も劣る
【０１３６】
（７）ＯＨＰ投影画像色再現性及び透明性
ＯＨＰシート「ＣＧ３７００」（３Ｍ社製）上のフルカラー画像を透過画像とし、ＯＨＰ「９５５０」（３Ｍ社製）にて白色壁面に投影した画像を目視評価すると共に、分光放射輝度計「ＰＲ６５０」（フォトリサーチ社製）にて測定し、国際照明委員会で規格されたＬ^*ａ^*ｂ^*表色系の明度Ｌ^*、赤又は緑の度合いを表すａ^*、黄又は青の度合いを表すｂ^*で決定される色空間立体の体積を求めた。数値が大きいほど色空間が広く、小さいほど色再現性が乏しいことを意味する。
【０１３７】
＜色空間体積＞
Ａ：２５０万以上
Ｂ：２００万以上２５０万未満
Ｃ：１５０万以上２００万未満
Ｄ：１５０万未満
【０１３８】
＜目視評価＞
Ａ：鮮やかで、かつ透明性に優れる
Ｂ：透明性は良好で、マゼンタの色再現性は優れるが、２次色（赤色、青色）はやや劣る
Ｃ：透明性はやや劣り、マゼンタ、２次色（赤色、青色）いずれの色再現性もやや劣る
Ｄ：くすみがあり、マゼンタ、２次色（赤色、青色）いずれの色再現性も劣る
【０１３９】
（実施例２〜４、参考例１、２及び比較例１〜５）
トナーとして、トナー（Ｂ）〜（Ｆ）、及び比較用トナー（ａ）〜（ｅ）を使用する以外は実施例１と同様にして評価した。結果を表４に示した。
【０１４０】
【表１】

【０１４１】
【表２】

【０１４２】
【表３】

【０１４３】
【表４】

【０１４４】
【発明の効果】
以上説明したように、本発明によれば、結着樹脂、着色剤、ワックス成分、及び荷電制御剤を含有するトナー粒子を少なくとも有し、着色剤には少なくともキナクリドン顔料及び溶性アゾ顔料が含まれ、キナクリドン顔料と溶性アゾ顔料のトナー粒子中における総含有量は１〜２０質量％で、キナクリドン顔料及び溶性アゾ顔料の含有量の質量比率は１０：９０〜５０：５０であり、ワックス成分の融点は４０〜１３０℃であり、かつ、フロー式粒子像測定装置で測定される円相当個数平均径が２〜１０μｍであり、平均円形度が０．９４０〜０．９９５であり、円形度標準偏差が０．０４０未満であることとすることによって、トナー粒子中で顔料の発色性や分散性を向上させることを可能とし、極めて鮮明な色彩と透明性、及び安定した摩擦帯電特性を有すると共に、耐久性、及び定着性に優れた乾式トナーを提供することができる。
【０１４５】
また、本発明では、トナーを２５℃で圧縮成型することにより得られる平滑な表面を有するトナー平板表面の水に対する接触角をθ₂₅とし、１００℃で２分間の加熱処理を行った前記トナー平板表面の水に対する接触角をθ₁₀₀としたときに、３°≦θ₁₀₀−θ₂₅≦１５°の関係を満たすと、良好な定着特性を実現する上でより一層効果的である。
【０１４６】
また、本発明では、荷電制御剤が、ジアルキルサリチル酸誘導体や含硫黄重合体であると、着色剤の良好な分散性及びトナーの良好な帯電特性を導き、現像性、転写性、及び着色力をバランス良く改善する上でより一層効果的である。
【０１４７】
また、本発明では、含硫黄重合体が、スルホン酸基を有する重合体であると、荷電制御剤の分散性及び着色剤の分散性を向上させ、着色力、透明性、及び帯電特性を改善する上でより一層効果的である。
【０１４８】
また、本発明では、平均円形度が０．９５５〜０．９９５で、円形度標準偏差が０．０３５未満であると、トナーの転写特性及び現像特性を改善する上でより効果的であり、平均円形度が０．９７０〜０．９９０で、円形度標準偏差が０．０１５以上０．０３５未満であると、より一層効果的である。
【０１４９】
また、本発明では、円形度０．９５０未満のトナー粒子が１５個数％以下であると、十分な現像効率を実現し、良好な画像を形成する上でより一層効果的である。
【０１５０】
また、本発明では、キナクリドン顔料が前記一般式［１］で示される顔料であると、色相や耐光性等の物理的安定性を向上させる上でより効果的であり、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ２０２、及びＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｖｉｏｌｅｔ １９の群から選ばれるいずれかであると、より一層効果的である。
【０１５１】
また、本発明では、溶性アゾ顔料が前記一般式［２］で示される顔料であると、分散性の改善や発色性、色調、及び帯電特性を向上させる上でより効果的であり、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：３、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：４、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：５、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５２：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５２：２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５７：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５８：２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５８：４、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ６４、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ６４：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ２００、及びＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｒｏｗｎ ５の群から選ばれるいずれかであると、より一層効果的である。
【０１５２】
また、本発明では、フルカラー画像形成時に用いられるマゼンタトナーであると、トナーの透明性を向上させ、優れた現像性を実現し、色再現性に優れたフルカラー画像を形成する上でより一層効果的である。
【０１５３】
さらに、本発明によれば、像担持体と、像担持体を帯電させる帯電手段と、帯電した像担持体に静電潜像を形成する静電潜像形成手段と、像担持体に形成された静電潜像を現像剤によって現像してトナー像を形成する現像手段と、形成されたトナー像を像担持体から転写材に転写する転写手段と、転写材上の未定着トナー像を転写材に定着させる定着手段とを有する画像形成装置において、前記乾式トナーを現像剤に用いると、高画像濃度でかつ鮮明な画像を形成することができる。
【図面の簡単な説明】
【図１】トナーの摩擦帯電量を測定する装置の説明図である。
【符号の説明】
１ 吸引機
２ 測定装置
３ スクリーン
４ ふた
５ 真空計
６ 風量調節弁
７ 吸引口
８ コンデンサ
９ 電位計[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner used in a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet method, or the like. More specifically, the present invention relates to a dry toner used in an image recording apparatus that can be used in a copying machine, a printer, a facsimile, a plotter, and the like.
[0002]
[Prior art]
In recent years, digital full-color copiers and printers have been put into practical use, and it has become possible to obtain high-quality images with excellent color reproducibility with no color unevenness as well as resolution and gradation. In a digital full-color copying machine, a color image original is color-separated with B (blue), G (green), and R (red) color filters, and then a latent image having a dot diameter of 20 to 70 μm corresponding to the original image. Y (yellow), M (magenta), C (cyan), and B (black) toners are used, and a large amount of toner is passed from the photoreceptor to the intermediate transfer member or not compared to a black and white copying machine. Transfer to transfer material. Among the color toners, the magenta toner is important for reproducing the skin color, and further, since the skin tone of the human image is a halftone, excellent developability is required.
[0003]
Conventionally, toner obtained by kneading and pulverizing a pigment as a colorant and a charge control agent together with a thermoplastic resin is generally used in the electrophotographic system. In this case, particularly in the magenta toner, since the pigment as the colorant is difficult to be dispersed, it is easy to cause a problem that the dispersed particles scatter light and reduce the transparency of the toner. For this reason, the color reproducibility of a multicolor image formed by superimposing a plurality of color toners is inferior, and the projected image formed by transferring and fixing to a transparent sheet for an overhead projector (OHP) is dark and colored. It had the disadvantage that the degree was low. Further, the magenta toner has drawbacks such as a low degree of coloring or an ideal magenta color tone.
[0004]
For these problems, improvement of pigments and dyes mainly used for magenta toners and improvement by combined use of pigments and dyes have been proposed. For example, JP-A-1-224777 discloses that a clear magenta toner can be obtained and light resistance is improved by using a quinacridone pigment and a xanthene dye together. JP-A-2-13968 discloses that a clear color image can be obtained without contaminating the fixing roller by using a quinacridone pigment and a methine pigment together.
[0005]
On the other hand, in JP-A-11-52625, C.I. I. Pigment Red Class 48 red pigments and L ^* a ^* b ^* B in the color system ^* By using a red pigment having a value of -5 or less in combination at a mixing ratio of 2 to 30% by mass with respect to the total pigment, a good magenta toner can be obtained, and the charging characteristics and light resistance of the toner are improved. Furthermore, a method for improving the heat resistance of the fixing roller is disclosed.
[0006]
However, even with these proposals, 1) excellent spectral reflection characteristics for color reproduction, a clear magenta color, 2) good dispersibility of the colorant in the resin, and high coloring power 3) A magenta toner that sufficiently satisfies all required characteristics such as having stable triboelectric charging characteristics in the environment and 4) good transparency has not been obtained.
[0007]
The toner applied to the dry development method is generally colored resin fine particles (toner particles) containing a binder resin, a colorant, and a wax component as main components, and the particle diameter is usually the number average diameter. Is about 6 to 15 μm. As a method for producing a toner composed of such colored resin fine particles, a binder resin, a colorant such as a dye or pigment and a magnetic material, a wax component, and the like are melt-pulverized, the kneaded product is cooled, pulverized, and a pulverized product is further obtained. A so-called pulverization method is generally used in which toner particles are obtained by classification.
[0008]
The toner obtained by such a method needs to be configured to have a positive or negative charge according to the charge polarity of the electrostatic image to be developed. In order to retain the charge in the toner, the triboelectric charging property of the binder resin, which is the main component of the toner, can be used, but this alone tends to reduce the charging property of the toner. Therefore, a charge control agent is added to the toner in order to impart a desired triboelectric chargeability to the toner. Although a toner containing such a charge control agent may exhibit a relatively high triboelectric charge amount, generally, a decrease in toner charge amount under high humidity and a decrease in charging speed under low humidity are observed.
[0009]
One reason for this is the adsorption / desorption of moisture near the charge control agent present in the toner particles or on the surface of the toner particles. It is considered that the characteristics are affected.
[0010]
As a charge control agent known in the technical field today, as a negatively chargeable one, a metal complex salt of monoazo dye, a metal complex salt of salicylic acid, a metal complex salt of naphthoic acid, a metal complex salt of dicarboxylic acid, a copper phthalocyanine pigment, etc. Is mentioned.
[0011]
On the other hand, Japanese Patent Application Laid-Open No. 63-184762 discloses a technology relating to a toner containing a charge control resin having acrylamidomethylpropanesulfonic acid as a constituent monomer. However, since the charge control resin has a good dispersibility with respect to the binder resin, it is necessary to increase the addition amount in order to efficiently exhibit the charge control ability when it is simply added. Further, since the coloring power of the toner is not taken into consideration at all, it is difficult to adapt to the toner.
[0012]
[Problems to be solved by the invention]
An object of the present invention is to provide a dry toner that solves the above-mentioned problems, and to provide a dry toner having at least good pigment dispersibility, high coloring power, and stable charging characteristics in the environment. It is in.
[0013]
A further object of the present invention is to provide a dry toner having a high image density and a very clear color and excellent light resistance.
[0014]
A further object of the present invention is to provide a dry toner that has a wide color space of a projected image and has excellent transparency in a fixed image of an OHP sheet.
[0015]
A further object of the present invention is to provide a dry toner that is excellent in negative chargeability, achieves good electrophotographic characteristics, and can stably realize a high-quality image over a long period of time.
[0016]
A further object of the present invention is to provide a dry toner having excellent fixability.
[0017]
[Means for Solving the Problems]
The present invention relates to a dry toner having at least toner particles containing a binder resin, a colorant, a wax component, and a charge control agent, and the colorant includes at least a quinacridone pigment and a soluble azo pigment, The total content of the soluble azo pigment in the toner particles is 1 to 20% by mass, the mass ratio of the content of the quinacridone pigment and the soluble azo pigment is 10:90 to 50:50, and the melting point of the wax component is 40 to 130. And the equivalent circle number average diameter measured by a flow type particle image measuring apparatus is 2 to 10 μm, the average circularity is 0.940 to 0.995, and the circularity standard deviation is 0.040. The present invention relates to a dry toner and an image forming apparatus using the dry toner.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The dry toner of the present invention is a dry toner having at least toner particles containing a binder resin, a colorant, a wax component, and a charge control agent, and the colorant contains at least a quinacridone pigment and a soluble azo pigment, The total content of the quinacridone pigment and the soluble azo pigment in the toner particles is 1 to 20% by mass, the mass ratio of the content of the quinacridone pigment and the soluble azo pigment is 10:90 to 50:50, and the melting point of the wax component is 40-130 ° C., circle equivalent number average diameter measured by flow type particle image measuring apparatus is 2-10 μm, average circularity is 0.940-0.995, and circularity standard deviation is It is less than 0.040.
[0019]
As a result of intensive studies, the inventors have selected and blended the colorant in the toner as described above, coexisted with the colorant, the wax component, and the charge control agent, and the particle shape of the toner satisfies the above conditions. When satisfied, it has been found that the development characteristics, charging characteristics, color tone, tinting strength, light resistance, durability, and fixability of the toner can be improved in a balanced manner, and the present invention has been completed.
[0020]
According to the knowledge of the present inventors, by selecting, blending and coexisting the colorant in the toner as described above, the dispersibility of the colorant in the toner particles is remarkably improved, and the development characteristics, color tone, and coloration of the toner are improved. Strength, light resistance, charging characteristics, etc. are improved in a well-balanced manner. Although it is not always clear about these reasons, the soluble azo pigment suppresses the re-aggregation of the quinacridone pigment that occurs in the toner particles, so that the ability of the colorants themselves can be greatly exhibited. I think that it is caused by creating.
[0021]
That is, by mixing a quinacridone pigment and a soluble azo pigment having similar primary particle structures in the toner particles, re-aggregation of each pigment composition itself is suppressed, and coexistence based on the interaction between the two pigment compositions. The effect creates a relatively slow reagglomeration state between both pigment compositions. As a result, it is presumed that the toner particles are provided with desirable color development and charging characteristics.
[0022]
Further, according to the knowledge of the present inventors, the colorant in the toner is selected and blended as described above, the wax component and the charge control agent are allowed to coexist, and the toner particle shape satisfies the above conditions. In this case, the dispersibility of the colorant in the toner particles is significantly improved. In the vicinity, the colorant can be controlled from the vicinity of the toner particle surface to the intermediate layer, and the wax component can be controlled to be present in the core portion, and the toner color tone, coloring power, light resistance, charging characteristics, durability, and fixability Can be made excellent.
[0023]
Since quinacridone pigments and soluble azo pigments used in the present invention have many hydrophilic functional groups, they form toner particles by polymerizing the granulated particles of the polymerizable monomer composition in an aqueous dispersion medium. When a quinacridone pigment or a soluble azo pigment is present alone, it moves toward the interface between the polymerizable monomer composition, which is a dispersoid, and the aqueous medium, resulting in reaggregation near the toner particle surface. . Such re-aggregates of quinacridone pigments and soluble azo pigments have an adverse effect on the charge amount and charging speed of the obtained toner particles.
[0024]
On the other hand, the quinacridone pigment and the soluble azo pigment are appropriately adjusted within the range of the blending amount satisfying the relationship as described above, and previously dispersed and mixed together with a part of the polymerizable monomer composition, followed by suspension polymerization. By producing toner, re-aggregation of quinacridone pigments and soluble azo pigments alone is prevented, creating a situation in which the ability of these colorants themselves can be greatly demonstrated, and in the toner particles Can be encapsulated while maintaining the interaction between the quinacridone pigment and the soluble azo pigment, so that the coexistence effect based on the interaction between the two pigment compositions causes a relatively slow reaggregation between the two pigment compositions. A state is created, and desirable charge characteristics and color developability can be imparted to the obtained toner.
[0025]
In particular, when the dry toner of the present invention is produced by a suspension polymerization method or an emulsion polymerization method, it is possible not only to prevent the problems caused by poor dispersion of the colorant as described above, but also the coexisting charge control agent is a toner particle. Orientation near the surface, imparting excellent charging characteristics, and also preventing migration of the colorant to the vicinity of the toner particle surface, further improving the charging characteristics, and further to the colorant present on the toner particle surface Problems caused by, for example, damage to the photosensitive member caused by the presence of needle-like crystals such as quinacridone pigment on the surface of the toner particles or fixing to the photosensitive member, and a coloring agent having high coloring power such as a soluble azo pigment Contamination of the photosensitive member due to the presence on the surface of the particle or sticking to the photosensitive member can be prevented, and high-quality images can be stably realized over a long period of time.
[0026]
Further, in the suspension polymerization method, the charge control agent is uniformly oriented in the vicinity of the toner particle surface, and the particle surface is uniformly covered with the dispersing agent by attracting with the dispersing agent in water. Is prevented, shows excellent granulation stability, and brings about a favorable effect in terms of production.
[0027]
The dry toner of the present invention contains a wax component having a melting point of 40 to 130 ° C., so that not only good fixability but also a release effect by the wax component is efficiently expressed, and a sufficient fixing area is secured. The In particular, when the dry toner of the present invention is produced by a suspension polymerization method or an emulsion polymerization method, since the wax component is encapsulated in the toner particles, the coexisting charge control agent is located near the surface from the toner particle surface, The colorant tends to localize from the vicinity of the toner particle surface to the intermediate layer, and the effects of the charge control agent and the colorant are efficiently exhibited.
[0028]
In particular, when a heat and pressure fixing unit is used, the dry toner of the present invention suppresses reaggregation of the colorant and transfer of the colorant to the toner surface as described above. A good fixed image can be obtained without causing a fixing failure called image peeling. In addition, since the dry toner of the present invention is manufactured by precisely controlling the toner particle shape so that the toner particle shape satisfies the above conditions, the thermal characteristics of the wax component encapsulated in the toner particles are extremely high. In addition, the load on the heating and pressurizing means is reduced, and the low-temperature fixing property and the offset resistance are also good.
[0029]
The dry toner of the present invention has a contact angle with water on the surface of a flat toner plate having a smooth surface obtained by compression molding the toner at 25 ° C. _{twenty five} And the contact angle of water on the surface of the toner flat plate subjected to the heat treatment at 100 ° C. for 2 minutes is θ ₁₀₀ 3 ° ≦ θ ₁₀₀ −θ _{twenty five} By satisfying the relationship of ≦ 15 °, the matching with the heat fixing device is further improved, and in particular, 5 ° ≦ θ ₁₀₀ −θ _{twenty five} It is preferable to satisfy the relationship of ≦ 10 °.
[0030]
θ ₁₀₀ And θ _{twenty five} If the difference is less than 3 °, the wax component in the toner particles does not ooze out efficiently on the surface of the toner particles at the time of heat fixing, and the application amount of the heat fixing means or the liquid for offset prevention is small. When it is used in a heat and pressure fixing device having a heat fixing means that is not made at all, the releasing effect may not be exhibited. And θ ₁₀₀ And θ _{twenty five} If the difference exceeds 15 °, a wax component is present near the surface of the toner particles, which may cause problems in developability and durability.
[0031]
The above contact angle difference can be controlled by adjusting the hydrophobicity and meltability of the entire toner particles. Specifically, the type of binder resin, glass transition temperature, type of wax component, toner particles It can be adjusted by appropriately selecting the type of other compounding agents to be added to the toner, and further, for example, additives such as inorganic fine powder added together with the toner particles.
[0032]
In the present invention, the contact angle of the toner flat surface obtained by compressing and molding the toner as described above with respect to water can be measured by a conventionally known method, and specific examples include the following measuring methods.
[0033]
A toner sample for measurement 0.5 g is set in KBr DISK PRESS (manufactured by Hitachi, Ltd.) for infrared absorption spectrum measurement. A load of 1960 N (200 kgf) is applied to this under a 25 ° C. atmosphere for 15 minutes to give a smooth surface. The toner flat plate is compression molded. Next, the contact angle meter “CA-S150” (manufactured by Kyowa Interface Science Co., Ltd.) is set so that the planar portion of the obtained toner plate is horizontal, and the contact angle θ with respect to water _{twenty five} Measure. Further, the toner flat plate produced in the same manner was subjected to a heat treatment for 2 minutes in an oven at 100 ° C., and then contact angle θ was similarly applied. ₁₀₀ Measure.
[0034]
In addition, ion exchange water is used for the measurement of the contact angle, and the detailed measurement method is to obtain the contact angle θ from the following formula based on the droplet method according to the instruction manual attached to the apparatus.
[Expression 1]
tan (θ / 2) = h / r
(In the formula, h represents the height of the droplet, and r represents the length of 1/2 of the bottom of the droplet.)
[0035]
As the contact angle in the present invention, the average value of the measured values obtained by performing the above measurement 5 times or more and excluding the lowest value of the measured values is used.
[0036]
In the dry toner of the present invention, a charge control agent is added from the viewpoint of improving the dispersibility and chargeability of the colorant. However, the negative charge is a colorless or light-colored toner that has a high charging speed and can stably maintain a constant charge amount. A control agent is preferred. In particular, a dialkyl salicylic acid derivative or a sulfur-containing polymer is preferable, and the incorporation of such a charge control agent leads to good dispersibility and charging characteristics of the colorant, and developability, transferability, and coloring power are improved in a well-balanced manner. The
[0037]
Examples of the dialkyl salicylic acid derivative used in the present invention include a metal complex of di-tert-butylsalicylic acid, specifically, an aluminum complex of di-tert-butylsalicylic acid. Since the charge control agent has a salicylic acid structure, it is easy to orient uniformly in the vicinity of the toner particle surface, exhibits an efficient charge imparting ability, suppresses migration of the colorant to the toner surface, and exists on the toner particle surface. The problem caused by the colorant to be avoided can be avoided. In particular, in the suspension polymerization method, the particle surface is uniformly covered with the dispersing agent by attracting with the dispersing agent in water, so that the coalescence of the particles is prevented, and excellent granulation stability is exhibited. preferable.
[0038]
Examples of the sulfur-containing polymer used in the present invention include polymer-type compounds having a sulfonic acid group in the side chain, and particularly a sulfonic acid group-containing (meth) acrylamide monomer in a copolymerization ratio of 2% by mass or more. A polymer comprising styrene or a styrene (meth) acrylic acid copolymer preferably containing 5% by mass or more, having a glass transition temperature (Tg) of 40 to 90 ° C. and a weight average molecular weight of 10,000 to 15,000. When the type compound is used, preferable charging characteristics can be enjoyed without affecting the thermal characteristics required of the toner particles. Furthermore, since the charge control agent contains a sulfonic acid group, the dispersibility of the charge control agent itself in the binder resin and the dispersibility of the colorant are improved, and coloring power, transparency, and charging characteristics are improved. Significantly improved.
[0039]
As said sulfonic-acid-group-containing (meth) acrylamide type monomer, what is represented by the following general formula [3] is preferable, and 2-acrylamide-2-methylpropanoic acid and 2-methacrylamide-2 are specifically mentioned. -Methyl propanoic acid etc. are mentioned.
[0040]
[Chemical 3]

[0041]
When the charge control agent used in the present invention is contained in an amount of 2 to 10 parts by mass with respect to 100 parts by mass of the binder resin, the toner particles are less likely to hold a reverse charge, and the charged state is further improved. Can do.
[0042]
In the dry toner of the present invention, each toner particle contains the same content of quinacridone pigment and soluble azo pigment by precisely controlling the toner particle shape so that the toner particle shape satisfies the above conditions. Therefore, the influence of the charging characteristics by the quinacridone pigment and the soluble azo pigment becomes uniform, thereby improving the developability and transferability in a well-balanced manner.
[0043]
In other words, the dry toner of the present invention reduces the toner circle equivalent number average diameter D1 (μm) to 2 to 10 μm, thereby reducing the reproducibility of image contours, particularly character images and line patterns. Will be good.
[0044]
In the dry toner of the present invention, the average circularity of the circularity frequency distribution of the toner is 0.940 to 0.995, preferably 0.955 to 0.995, more preferably 0.970 to 0.990. As a result, the transferability of a toner having a small particle diameter, which has been difficult in the past, is greatly improved.
[0045]
Furthermore, the dry toner of the present invention can be developed by setting the circularity standard deviation of the circularity frequency distribution of the toner to less than 0.040, preferably less than 0.035, more preferably from 0.015 to less than 0.035. Can greatly improve gender issues.
[0046]
Further, the dry toner of the present invention has a sufficient level of development efficiency in image formation and good image formation by reducing the toner with an average circularity of less than 0.955 in the circularity frequency distribution to 15% or less. Become.
[0047]
The toner particle size can be adjusted by the toner particle manufacturing method and manufacturing conditions, toner classification, and mixing of the classified products. The toner particle shape can be adjusted by the toner particle manufacturing method and the manufacturing conditions. It can be adjusted by a spheronization process by a mechanical impact method.
[0048]
The equivalent circle diameter, circularity, and frequency distribution of the toner in the present invention are used as a simple method for quantitatively expressing the shape of the toner particles. In the present invention, the flow type particle image measuring apparatus is used. For example, it is measured using “FPIA-1000 type” (manufactured by Toa Medical Electronics Co., Ltd.), and is calculated using the following equation.
[0049]
[Expression 2]

[Equation 3]

[0050]
Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define.
[0051]
The circularity in the present invention is an index indicating the degree of unevenness of toner particles, and is 1.000 when the toner particles are perfectly spherical, and the circularity becomes smaller as the surface shape becomes more complicated.
[0052]
In the present invention, the circle-equivalent number average diameter D1 (μm) and the particle size standard deviation SDd, which mean the average value of the particle size frequency distribution on the basis of the number of toners, are the particle size (central value) at the dividing point i of the particle size distribution. Is di, and the frequency is fi.
[0053]
[Expression 4]

[Equation 5]

[0054]
In addition, the average circularity C and the circularity standard deviation SDc, which mean the average value of the circularity frequency distribution, can be obtained from the following equation when the circularity (center value) at the division point i of the particle size distribution is ci and the frequency is fci. Calculated.
[0055]
[Formula 6]

[Expression 7]

[0056]
As the quinacridone pigment according to the present invention, General Examples thereof include pigments represented by the formula [1], and these can be used alone or in combination.
[0057]
[Formula 4]

[0058]
Among these, C.I. I. Pigment Red 122, C.I. I. Pigment Red 202, and C.I. I. Pigment Violet 19 (each according to the name described in the color index 4th edition) is preferably used from the viewpoint of physical stability such as hue and light resistance.
[0059]
On the other hand, the soluble azo pigment according to the present invention is an insoluble azo lake pigment formed by forming a salt of a water-soluble or poorly water-soluble azo dye having a hydrophilic group with a metal such as Ca, Ba, Sr, or Mn. Such soluble azo pigments include: General Examples thereof include pigments represented by the formula [2], and these can be used alone or in combination.
[0060]
[Chemical formula 5]

[0061]
Examples of the soluble azo pigment include C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 48: 2, C.I. I. Pigment Red 48: 3, C.I. I. Pigment Red 48: 4, C.I. I. Pigment Red 48: 5, C.I. I. Pigment Red 52: 1, C.I. I. Pigment Red 52: 2, C.I. I. Pigment Red 57: 1 , C.I. I. Pigment Red 58: 2, C.I. I. Pigment Red 58: 4, C.I. I. Pigment Red 64, C.I. I. Pigment Red 64: 1, C.I. I. Pigment Red 200, and C.I. I. Pigment Brown 5 (each according to the name described in the color index 4th edition) and the like. I. Pigment Red 57: 1 is preferably used from the viewpoints of improving dispersibility by suppressing reaggregation of the quinacridone pigment, and further improving color developability, color tone, and charging characteristics.
[0062]
In the dry toner of the present invention, the total content of the quinacridone pigment and the soluble azo pigment in the toner particles is 1 to 20% by mass, preferably 3 to 10% by mass, and the mass ratio of both contents is Quinacridone pigment: soluble azo pigment is blended so as to satisfy 10:90 to 50:50.
[0063]
When the total content of the quinacridone pigment and the soluble azo pigment in the toner particles is less than 1% by mass, the function as a colorant may not be sufficiently achieved. On the other hand, when the amount exceeds 20% by mass, the presence of the colorant in the toner particles becomes excessive, the coexistence effect of the quinacridone pigment and the soluble azo pigment disappears, and the reaggregation of the colorant proceeds. , May adversely affect charging characteristics and fixability.
[0064]
Further, when the mass ratio of the content of the quinacridone pigment and the soluble azo pigment is outside the range of quinacridone pigment: soluble azo pigment = 10: 90 to 50:50, not only the coexistence effect disappears but also the soluble azo pigment. If the content ratio is less than 50% by mass, sufficient coloring power cannot be obtained, and damage to the photoreceptor caused by excessive quinacridone pigment, fixing to the photoreceptor, or poor fixing may occur. When the amount exceeds 50% by mass, problems such as a decrease in light resistance, contamination of the photosensitive member caused by an excessive soluble azo pigment, and fixation on the photosensitive member may occur.
[0065]
The dry toner of the present invention essentially contains a quinacridone pigment and a soluble azo pigment as colorants, and may further contain other colorants such as other pigments and dyes.
[0066]
Moreover, the surface of the quinacridone pigment and soluble azo pigment according to the present invention can be treated by a conventionally known method. By using the surface-treated colorant, re-aggregation of the colorant can be prevented, dispersibility of the colorant in the toner particles can be improved, and furthermore, the chargeability of the toner can be brought into a preferable state. The characteristics as described above can be further improved.
[0067]
Surface treatment agents that can preferably treat quinacridone pigments and soluble azo pigments according to the present invention include polyethylene wax, polypropylene wax, natural rosin (such as tall oil rosin, gum rosin, rod rosin), and purified rosin obtained by extraction from natural rosin ( Rosin compounds such as abietic acid), modified rosins (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), synthetic rosins (such as styrene acrylic rosin acid), and alkali metal salts and ester compounds of the above rosin compounds Can be mentioned.
[0068]
The wax component used in the present invention has a main endothermic peak temperature (melting point) of 40 to 130 ° C. in a DSC curve measured according to “ASTM D3418-82”. When the melting point of the wax component is in the above range, fixing property, transparency, and coloring power can be improved.
[0069]
Specific examples of the wax component that can be used in the present invention include paraffin wax, microcrystalline wax, Petrolatum Petroleum waxes and derivatives thereof, montan waxes and derivatives thereof, hydrocarbon waxes and derivatives thereof by Fischer-Tropsch process, polyolefin waxes and derivatives thereof typified by polyethylene, natural waxes such as carnauba wax and candelilla wax and their Derivatives and the like can be mentioned. Derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. Examples thereof include alcohols such as higher aliphatic alcohols; aliphatics such as stearic acid and palmitic acid or compounds thereof; acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, and animal waxes. These can be used alone or in combination.
[0070]
In particular, it is preferable to use a low melting point wax such as paraffin wax and a high melting point wax such as a hydrocarbon wax by Fischer-Tropsch method because the fixability and coloring power can be further improved.
[0071]
The dry toner of the present invention can bring about good fixability by containing the wax component in an amount of 1 to 30 parts by mass, more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the binder resin.
[0072]
As a method for producing the dry toner according to the present invention, the binder resin, the colorant according to the present invention, the wax component and the like are melt-kneaded with a pressure kneader or the like, and then the cooled kneaded product is finely adjusted to a desired toner particle size. A pulverization method in which a finely pulverized product is further classified to adjust a particle size distribution to obtain a dry toner; Japanese Patent Publication Nos. 36-10231, 59-53856, and 59-61842. A method for directly producing toner particles by using the suspension polymerization method described in the above; a spherical toner obtained by atomizing a melt-kneaded product in air using a disk or a multi-fluid nozzle described in JP-B-56-13945 A known method such as a method for producing particles; and an emulsion polymerization method represented by a soap-free polymerization method can be used. Produced by a suspension polymerization method it is desirable.
[0073]
Control of the toner average circularity, circularity standard deviation, and the number of toners having a circularity of less than 0.950 as described above is performed during the polymerization reaction from the granulation step to the polymerization step in the method for producing toner particles by suspension polymerization. This is possible depending on the pH of the aqueous dispersion medium.
[0074]
The toner particles produced by the suspension polymerization method are prepared by mixing a polymerizable monomer that forms a binder resin by polymerization, a colorant according to the present invention, a polar resin, a wax component, a charge control agent, and a polymerization initiator. The polymerizable monomer composition is prepared, and the polymerizable monomer composition is dispersed in an aqueous medium to produce particles of the polymerizable monomer composition, and the polymerizable monomer composition is formed in the aqueous medium. It is produced by polymerizing polymerizable monomers in the particles of the product.
[0075]
Examples of the binder resin for toner particles used in the present invention include commonly used styrene- (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers. In a method for directly obtaining toner particles by a polymerization method, a monomer for forming them is used.
[0076]
Specific examples of such polymerizable monomers include styrene; styrene monomers such as o- (m-, p-) methylstyrene and m- (p-) ethylstyrene; methyl (meth) acrylate, (Meth) ethyl acrylate, propyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid ester monomers such as 2-ethylhexyl acid, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) acrylonitrile, acrylamide An ene monomer is preferably used.
[0077]
These may be used alone or in general so that the theoretical glass transition temperature (Tg) described in the publication polymer handbook 2nd edition III-p139-192 (John Wiley & Sons) is 40-75 ° C. It is used by mixing the body appropriately. When the theoretical glass transition temperature is less than 40 ° C., problems are likely to occur in terms of storage stability and durability stability of the toner. May decrease.
[0078]
In the present invention, a polar resin such as a polyester resin or a polycarbonate resin can be used in combination with the above-described binder resin.
[0079]
For example, in the case of directly producing toner particles by suspension polymerization or the like, when a polar resin is added during the polymerization reaction from the dispersion step to the polymerization step, the polymerizable monomer composition that becomes toner particles and the aqueous dispersion medium The polar resin added can be controlled so as to form a thin layer on the surface of the toner particles or to have a gradient from the surface of the toner particles toward the center according to the balance of polarity to be exhibited. At this time, by using a polar resin that interacts with the colorant according to the present invention, dialkyl salicylic acid and sulfur-containing polymer, the state of the colorant present in the toner particles can be brought into a desired form. It is.
[0080]
The addition amount of the polar resin is preferably 1 to 25 parts by mass, more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the binder resin. If it is less than 1 part by mass, the presence state of the polar resin in the toner particles tends to be non-uniform, while if it exceeds 25 parts by mass, the thin layer of the polar resin formed on the surface of the toner particles becomes thick.
[0081]
Specific examples of the polar resin used in the present invention include polyester resins, epoxy resins, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and styrene-maleic acid copolymers. In particular, a polyester resin having a peak molecular weight of 3000 to 10,000 is preferable because it can improve the fluidity, negative triboelectric charging characteristics, and transparency of toner particles.
[0082]
Furthermore, in the present invention, it is preferable to use a crosslinking agent during the synthesis of the binder resin in order to increase the mechanical strength of the toner particles and to control the molecular weight of the toner particles.
[0083]
Examples of the crosslinking agent used in the dry toner of the present invention include divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1 , 4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200, # 400, # 600 diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester type diacrylate (M NDA Nippon Kayaku), and that instead of the dimethacrylate of the above diacrylate.
[0084]
Polyfunctional crosslinkers include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxy, polyethoxy Phenyl) propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate and triallyl trimellitate.
[0085]
These crosslinking agents are preferably used in an amount of 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, with respect to 100 parts by mass of the polymerizable monomer.
[0086]
When the dry toner of the present invention is produced by suspension polymerization, specific examples of the polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile) and 2,2′-azobis. An azo group such as isobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, or Diazo polymerization initiators: Peroxide polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide are used.
[0087]
Although the usage-amount of these polymerization initiators changes with the target degree of polymerization, generally 5-20 mass parts is used with respect to 100 mass parts of polymerizable vinylic monomers. The kind of the polymerization initiator varies slightly depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.
[0088]
When the dry toner of the present invention is produced by the suspension polymerization method, known inorganic and organic dispersants can be used as the dispersant used in preparing the aqueous dispersion medium.
[0089]
Specifically, as the inorganic dispersant, for example, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, Examples include calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina.
[0090]
Examples of the organic dispersant include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, and starch.
[0091]
Commercially available nonionic, anionic and cationic surfactants can also be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate can be used.
[0092]
When the dry toner of the present invention is produced by the suspension polymerization method, as the dispersant used in preparing the aqueous dispersion medium, an inorganic poorly water-soluble dispersant is preferable, and the hardly water-soluble inorganic dispersion that is soluble in acid is also used. It is recommended to use an agent. Moreover, in this invention, when preparing a water-based dispersion medium using a slightly water-soluble inorganic dispersing agent, these dispersing agents are 0.2-2. It is preferable to use it in such a ratio that it becomes 0 parts by mass. Moreover, in this invention, it is preferable to prepare an aqueous dispersion medium using 300-3,000 mass parts water with respect to 100 mass parts of polymerizable monomer compositions.
[0093]
In the present invention, when preparing an aqueous dispersion medium in which the above-mentioned poorly water-soluble inorganic dispersant is dispersed, a commercially available dispersant may be used as it is, but a dispersion having a fine uniform particle size may be used. In order to obtain agent particles, a slightly water-soluble inorganic dispersant as described above may be prepared in a liquid medium such as water under high-speed stirring. For example, when tricalcium phosphate is used as a dispersant, a preferred dispersant can be obtained by mixing aqueous sodium phosphate solution and aqueous calcium chloride solution at high speed to form fine particles of tricalcium phosphate. .
[0094]
The dry toner of the present invention is mainly used as a one-component developer. However, the dry toner of the present invention and a carrier can be mixed and used as a two-component developer. The toner of the present invention may further contain various additives according to the purpose, and such additives are blended mainly for the purpose of mainly improving the fluidity of toner particles. Examples include inorganic fine powders such as hydrophobic surface-treated silica fine particles, and conductive fine particles such as conductive metal oxide fine particles that are blended mainly for the purpose of controlling the chargeability of toner particles. A known material can be used.
[0095]
The dry toner of the present invention is suitable for a magenta toner used for forming a full-color image.
[0096]
The image forming apparatus of the present invention is formed on an image carrier, a charging unit for charging the image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the charged image carrier, and the image carrier. Developing means for developing the electrostatic latent image with a developer to form a toner image, transfer means for transferring the formed toner image from the image carrier to a transfer material, and transferring an unfixed toner image on the transfer material Fixing means for fixing to the material, and the dry toner of the present invention is used as a developer.
[0097]
The image forming apparatus of the present invention is not particularly limited as long as the dry toner of the present invention can be applied according to the type of the dry toner of the present invention, for example, a one-component developer or a two-component developer. These means and members can be used. The image forming apparatus of the present invention is preferably applied to a full-color image forming apparatus using the dry toner of the present invention as magenta toner.
[0098]
【Example】
Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited thereto.
[0099]
(Toner Production Example 1)
In a 4-liter flask for 2 liters equipped with a high-speed stirring device TK type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), 700 parts by mass of ion-exchanged water and 0.1 mol / liter-Na _Three PO _Four 800 parts by mass of the aqueous solution was added, the number of revolutions of the high-speed agitator was set to 12000 rpm, and the mixture was heated to 65 ° C. Here 1.0 mol / liter-CaCl ₂ 70 parts by weight of aqueous solution is added, and a minute water-insoluble dispersion stabilizer Ca _Three (PO _Four ) ₂ An aqueous dispersion medium containing was prepared.
[0100]
on the other hand,

A mixture of K. A pigment dispersion composition was prepared by dispersing for 1 hour using a homodisper (manufactured by Tokushu Kika Kogyo Co., Ltd.).
[0101]
In another container,
・ Styrene monomer 30 parts by mass
・ 23 parts by mass of 2-ethylhexyl acrylate monomer
・ 0.3 parts by weight of divinylbenzene monomer
Ester wax (melting point = 50 ° C) 4 parts by mass
-Polyethylene wax (melting point = 120 ° C) 5 parts by mass
63 parts by mass of the pigment dispersion composition was added to the mixture consisting of the components, dispersed and dissolved while heating to 65 ° C., and then 5 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) was added. Then, a polymerizable vinyl monomer composition as a dispersoid was prepared.
[0102]
Next, the polymerizable monomer composition is put into the aqueous dispersion medium, and N.sub. ₂ Under the atmosphere, the polymerizable monomer composition was granulated by stirring for 5 minutes while maintaining the rotation speed of the high-speed stirring device at 15000 rpm. Thereafter, the stirring device was replaced with a paddle stirring blade, and maintained at the same temperature while stirring at 200 rpm, and the polymerization reaction was completed when the polymerization conversion rate of the polymerizable vinyl monomer reached almost 100%. .
[0103]
After completion of the polymerization, the residual monomer was distilled off under reduced pressure by heating, and after cooling, diluted hydrochloric acid was added to dissolve the hardly water-soluble dispersant. Further, water washing was repeated several times, and then a drying process was performed using a conical ribbon dryer (manufactured by Okawara Seisakusho) to obtain polymer particles (A).
[0104]
100 parts by mass of the polymer particles (A) and silica oil-treated silica fine powder (BET; 200 m ² / G) 1.5 parts by mass was dry-mixed with a Henschel mixer (manufactured by Mitsui Kinzoku Co., Ltd.) to obtain toner (A).
[0105]
The toner (A) has a circle-equivalent number average diameter of 5.7 μm, an average circularity in the circularity frequency distribution of 0.987, a circularity standard deviation of 0.027, and the number of toner particles having a circularity of less than 0.950. Was 5.4% by number.
[0106]
(Toner Production Examples 2 to 5)
Except for changing the kind and addition amount of the quinacridone pigment and the soluble azo pigment, the treatment agent of the soluble azo pigment, the kind and addition amount of the charge control agent, and the kind and addition amount of the wax component, the same as in the toner production example 1 Thus, after obtaining polymer particles (B) to (E), toners (B) to (E) were prepared.
[0107]
(Toner Production Example 6)
The following materials are mixed in advance, melt-kneaded with a twin screw extruder, the cooled kneaded product is roughly pulverized with a hammer mill, the coarsely pulverized product is finely pulverized with a jet mill, and the resulting finely pulverized product is classified and classified. It was set as the powder (F).
・ Binder resin 100 parts by mass
[Styrene-2-ethylhexyl acrylate-divinylbenzene copolymer peak molecular weight = 16,000, Mw / Mn = 5.0, Tg = 60 ° C.]
・ Quinacridone pigment 3 parts by weight
(C.I. Pigment Red 122)
・ 3.5 parts by weight of soluble azo pigment
(C.I. Pigment Red 48: 1)
・ Charge control agent 3 parts by mass
(Aluminum compound of dialkyl salicylic acid)
・ 10 parts by mass of paraffin wax (melting point = 65 ° C.)
[0108]
Using the classified powder (F), a toner (F) was prepared in the same manner as in Toner Production Example 1.
[0109]
(Comparative Toner Production Example 1)
Except for changing only 7 parts by weight of “CI Pigment Red 122” as a colorant, 2 parts of boron compound of benzyl acid as a charge control agent, and 10 parts of ester wax (melting point = 60 ° C.) as a wax component. Comparative polymer particles (a) were obtained in the same manner as in Toner Production Example 1, and then comparative toner (a) was prepared.
[0110]
(Comparative toner production example 2)
Change to using only 5 parts by weight of “CI Pigment Red 57: 1” as a colorant, 2 parts of boron compound of benzyl acid as a charge control agent, and 10 parts of ester wax (melting point = 60 ° C.) as a wax component. Except for the above, Comparative Polymer Particles (b) were obtained in the same manner as in Toner Production Example 1, and then Comparative Toner (b) was prepared.
[0111]
(Comparative toner production example 3)
Except for changing to using 5 parts by weight of “CI Pigment Red 176” as a colorant, 1 part of an aluminum compound of dialkylsalicylic acid as a charge control agent, and 10 parts of ester wax (melting point = 60 ° C.) as a wax component, Comparative polymer particles (c) were obtained in the same manner as in Toner Production Example 1, and then comparative toner (c) was prepared.
[0112]
(Comparative toner production example 4)
The classified product (d) in the same manner as in Toner Production Example 6 except that the types and addition amounts of quinacridone pigment and soluble azo pigment, 3 parts of calixarene as a charge control agent, and the addition amount of the wax component were changed. After that, a comparative toner (d) was prepared.
[0113]
(Comparative Toner Production Example 5)
The classified product (e) was obtained in the same manner as in Toner Production Example 6 except that the type and addition amount of quinacridone pigment and soluble azo pigment, 2 parts of calixarene as a charge control agent, and no wax component were added. Thereafter, a comparative toner (e) was prepared.
[0114]
Tables 1 and 2 summarize main prescription contents and toner particle shapes of the above toner production examples and comparative toner production examples.
[0115]
(Toner Production Example 7)
Except for changing to using 5 parts by weight of “CI Pigment Blue 15: 3” as a colorant and 10 parts of ester wax (melting point = 60 ° C.) as a wax component, the same as in Production Example 1 of the toner described above. After obtaining polymer particles, a cyan toner was prepared.
[0116]
(Toner Production Example 8)
A polymer in the same manner as in Toner Production Example 1 except that 7 parts by weight of “CI Pigment Yellow 93” is used as the colorant and 10 parts of ester wax (melting point = 60 ° C.) is used as the wax component. After obtaining the particles, a yellow toner was prepared.
[0117]
Example 1
Regarding the charging stability, when the triboelectric charge amount of the toner (A) obtained in Production Example 1 was measured under normal temperature and normal humidity and high temperature and high humidity, no significant difference was found, and the toner (A) was stable in environmental charge. It was excellent in nature.
[0118]
As the image forming apparatus, a laser beam printer (Canon: LBP-2160) was modified and used. The toner (A) obtained in the toner production example 1 is put into the process cartridge of this image forming apparatus, and the plain paper for copying machines (75 g / m) is used as a transfer material. ² ) And printed out 10,000 text images with a print area ratio of 4% in single color mode at a printout speed of 28 sheets (A4 size) / min. A good image equivalent to the initial one was obtained. With respect to this, when the surface of the photoconductor was observed, filming of the photoconductor surface, adhesion of residual toner, and damage did not occur, and it was in a very good state. Further, no image peeling was observed.
[0119]
Furthermore, 0.1 mg / cm ² To 1.0 mg / cm ² In this range, several types of solid images with different toner amounts on the transfer paper were created, and the relationship between the toner amount on the transfer paper and the image density was evaluated. As a result, a sufficient image was obtained even if the toner amount on the transfer paper was relatively small. A density image was obtained, and the high coloring power could be confirmed.
[0120]
The toner amount on the transfer paper is 0.6 mg / cm. ² When a solid image of a certain degree was prepared and image light resistance was evaluated, it showed excellent light resistance.
[0121]
Using the cyan toner obtained in Toner Production Example 7 and the yellow toner obtained in Toner Production Example 8 in addition to magenta toner (A), plain paper for copying machines (75 g / m) was obtained in the same manner as described above. ² When a full-color image was printed out on (), an image with excellent color reproducibility was obtained, which was good even in superposition of secondary colors or higher. In addition, when printed on an OHP sheet “CG3700” (manufactured by 3M) and evaluated for an OHP projection image, it was excellent in transparency, and also excellent in superposition of secondary colors or more, and had a wide and excellent color space. A projection image was obtained.
[0122]
These evaluation results are summarized in Table 4.
In addition, the evaluation method and its evaluation criteria are as follows, and Examples 2 to 6 and Comparative Examples 1 to 5 described later also follow these.
[0123]
(Evaluation methods)
(1) Environmental charge stability of toner
FIG. 1 is a schematic explanatory diagram of an apparatus for measuring the triboelectric charge amount of toner. A mixture of toner (without external additives) and carrier is put in a polyethylene bottle having a capacity of 50 to 100 ml, and shaken and charged by shaking 500 times. As the carrier, a ferrite carrier coated with a silicone resin (average particle size 35 μm) is used, and the mixing weight ratio of the toner and the carrier is 7:93.
[0124]
The mixture (toner and carrier) W is placed in a metal measuring container 2 having a 500 mesh screen 3 at the bottom. ₀ (G: about 0.5 to 1.5 g) is put and a metal lid 4 is formed. Weigh the entire measurement container 2 at this time W ₁ (G). Next, in the suction machine 1 (the part in contact with the measurement container 2 is at least insulative), suction from the suction port 7 and adjustment of the air volume control valve 6 are performed to set the pressure of the vacuum gauge 5 to 2450 (hpa). In this state, suction is performed for 2 minutes to remove the toner by suction. At this time, the triboelectric charge amount Q (mC / kg) of the toner is defined as follows when the toner is 100% corrected.
[0125]
[Equation 8]

[0126]
The environmental charge stability of the toner was determined by measuring the triboelectric charge quantity Q of the toner at normal temperature and normal humidity (23 ° C., 60% RH) and high temperature and high humidity (35 ° C., 90% RH).
[0127]
<Frictional charge Q (normal temperature and humidity)>
A: Less than -35 mC / kg
B: -35 mC / kg or more, less than -30 mC / kg
C: -30 mC / kg or more, less than -25 mC / kg
D: -25 mC / kg or more
[0128]
<Frictional charge Q (high temperature and high humidity)>
A: Difference from triboelectric charge Q at normal temperature and humidity is less than 5
B: The difference from the triboelectric charge Q at normal temperature and humidity is 5 or more and less than 10
C: The difference from the triboelectric charge Q at normal temperature and humidity is 10 or more and less than 15
D: The difference from the triboelectric charge Q at normal temperature and humidity is 15 or more
[0129]
(2) Matching with photoconductor
The filming on the surface of the photoreceptor, the sticking of residual toner, and the occurrence of damage and the effect on the printout image were visually evaluated.
A: Very good (not generated)
B: Good (slight scratches are seen but there is no effect on the image)
C: Normal (there is sticking or scratching, but there is little effect on the image)
D: Poor (there is much sticking and causes vertical stripe-like image defects)
[0130]
(3) Image peeling
Slightly thick transfer paper (105 g / m ² , A4 size) and the toner amount is 0.8 mg / cm ² A solid image was prepared so as to have a degree, and the occurrence of image peeling on the surface of the obtained image was visually evaluated. As the number of image peeling portions is smaller, the occurrence is suppressed.
A: Not generated
B: 1 to 5 locations
C: 6 or more and 10 or less
D: 11 or more locations (or image peeling with a diameter of 2 mm or more occurs)
[0131]
(4) Coloring power
0.1 mg / cm ² To 1.0 mg / cm ² After creating several types of solid images with different toner amounts on the transfer paper in the range of, measuring their image density using “X-Rite 504”, and determining the relationship between the toner amount on the transfer paper and the image density, In particular, the toner amount on the transfer paper is 0.5 mg / cm ² The coloring power was evaluated relatively with the image density corresponding to the above case.
A: Toner amount on transfer paper is 0.5 mg / cm ² And the image density is 1.4 or higher
B: Toner amount on transfer paper is 0.5 mg / cm ² The image density is 1.35 or more and less than 1.40
C: The amount of toner on the transfer paper is 0.5 mg / cm ² The image density is 1.20 or more and less than 1.35
D: Toner amount on transfer paper is 0.5 mg / cm ² And the image density is less than 1.20
[0132]
(5) Image light resistance
The amount of toner on the transfer paper is 0.6 mg / cm ² A solid image of the same degree was prepared and evaluated according to “JIS K 7102” using an ultraviolet auto fade meter “FAL-AU” (manufactured by Suga Test Instruments Co., Ltd.) using a carbon arc lamp as a light source. The maximum irradiation time was 240 hours, the image density maintenance ratio before and after the light irradiation was calculated, and the light resistance of the image was evaluated. The closer the image density maintenance rate (%) is to 100%, the better the image light resistance.
A: 90% or more
B: 80% or more and less than 90%
C: 70% or more and less than 80%
D: Less than 70%
[0133]
(6) Color reproducibility on plain paper
Plain paper for copying machines (75 g / m ² ) Visual evaluation of the above full-color image and measurement with “X-Rite SP68” (manufactured by X-Rite). ^* a ^* b ^* Lightness L of the color system ^* A representing the degree of red or green ^* , B representing the degree of yellow or blue ^* The volume of the color space solid determined by is obtained. A larger value means a wider color space, and a smaller value means poor color reproducibility.
[0134]
<Color space volume>
A: Over 2.5 million
B: 2 million to less than 2.5 million
C: 1.5 million to less than 2 million
D: Less than 1.5 million
[0135]
<Visual evaluation>
A: Excellent color reproducibility of magenta and secondary colors (red and blue)
B: Magenta color reproducibility is excellent, but secondary colors (red, blue) are slightly inferior
C: Magenta and secondary colors (red and blue) are slightly inferior in color reproducibility
D: Magenta and secondary colors (red and blue) are inferior in color reproducibility
[0136]
(7) OHP projection image color reproducibility and transparency
A full-color image on the OHP sheet “CG3700” (manufactured by 3M) was used as a transmission image, and the image projected on the white wall surface by OHP “9550” (manufactured by 3M) was visually evaluated, and a spectral radiance meter “PR650” ( L measured by Photo Research) and standardized by the International Lighting Commission ^* a ^* b ^* Lightness L of the color system ^* A representing the degree of red or green ^* , B representing the degree of yellow or blue ^* The volume of the color space solid determined by is obtained. A larger value means a wider color space, and a smaller value means poor color reproducibility.
[0137]
<Color space volume>
A: Over 2.5 million
B: 2 million to less than 2.5 million
C: 1.5 million to less than 2 million
D: Less than 1.5 million
[0138]
<Visual evaluation>
A: Vivid and excellent in transparency
B: Transparency is good and color reproduction of magenta is excellent, but secondary colors (red and blue) are slightly inferior
C: Transparency is slightly inferior, and magenta and secondary colors (red and blue) are slightly inferior in color reproducibility.
D: Dull and magenta and secondary colors (red and blue) are inferior in color reproducibility
[0139]
(Example 2 4, Reference Examples 1 and 2 And Comparative Examples 1-5)
Evaluation was performed in the same manner as in Example 1 except that toners (B) to (F) and comparative toners (a) to (e) were used as toners. The results are shown in Table 4.
[0140]
[Table 1]

[0141]
[Table 2]

[0142]
[Table 3]

[0143]
[Table 4]

[0144]
【The invention's effect】
As described above, according to the present invention, at least toner particles containing a binder resin, a colorant, a wax component, and a charge control agent are included, and the colorant includes at least a quinacridone pigment and a soluble azo pigment. The total content of the quinacridone pigment and the soluble azo pigment in the toner particles is 1 to 20% by mass, the mass ratio of the content of the quinacridone pigment and the soluble azo pigment is 10:90 to 50:50, and the melting point of the wax component Is 40 to 130 ° C., the circle equivalent number average diameter measured by a flow type particle image measuring apparatus is 2 to 10 μm, the average circularity is 0.940 to 0.995, and the circularity standard deviation is Is less than 0.040, thereby making it possible to improve the color developability and dispersibility of the pigment in the toner particles, and provide extremely clear color and transparency, and stable Which has a friction charging characteristic, it is possible to provide durability, and the dry toner having excellent fixing property.
[0145]
In the present invention, the contact angle of water on the flat surface of the toner having a smooth surface obtained by compression molding the toner at 25 ° C. is θ _{twenty five} And the contact angle of water on the surface of the toner flat plate subjected to the heat treatment at 100 ° C. for 2 minutes is θ ₁₀₀ 3 ° ≦ θ ₁₀₀ −θ _{twenty five} When the relationship of ≦ 15 ° is satisfied, it is more effective in realizing good fixing characteristics.
[0146]
In the present invention, when the charge control agent is a dialkyl salicylic acid derivative or a sulfur-containing polymer, it leads to good dispersibility of the colorant and good charging characteristics of the toner, and developability, transferability, and coloring power are improved. It is even more effective in improving balance.
[0147]
In the present invention, when the sulfur-containing polymer is a polymer having a sulfonic acid group, the dispersibility of the charge control agent and the dispersibility of the colorant are improved, and the coloring power, transparency, and charging characteristics are improved. This is even more effective.
[0148]
In the present invention, when the average circularity is 0.955 to 0.995 and the circularity standard deviation is less than 0.035, it is more effective in improving toner transfer characteristics and development characteristics. When the average circularity is 0.970 to 0.990 and the circularity standard deviation is 0.015 or more and less than 0.035, it is more effective.
[0149]
In the present invention, if the number of toner particles having a circularity of less than 0.950 is 15% by number or less, sufficient development efficiency can be realized and a more effective image can be formed.
[0150]
In the present invention, the quinacridone pigment is General The pigment represented by the formula [1] is more effective in improving physical stability such as hue and light resistance. I. Pigment Red 122, C.I. I. Pigment Red 202, and C.I. I. If it is selected from the group of Pigment Violet 19, it is even more effective.
[0151]
In the present invention, the soluble azo pigment is General The pigment represented by the formula [2] is more effective in improving dispersibility and improving color development, color tone, and charging characteristics. I. Pigment Red 48: 1, C.I. I. Pigment Red 48: 2, C.I. I. Pigment Red 48: 3, C.I. I. Pigment Red 48: 4, C.I. I. Pigment Red 48: 5, C.I. I. Pigment Red 52: 1, C.I. I. Pigment Red 52: 2, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 58: 2, C.I. I. Pigment Red 58: 4, C.I. I. Pigment Red 64, C.I. I. Pigment Red 64: 1, C.I. I. Pigment Red 200, and C.I. I. It is even more effective if it is selected from the group of Pigment Brown 5.
[0152]
In the present invention, the magenta toner used for forming a full-color image improves the transparency of the toner, achieves excellent developability, and is more effective in forming a full-color image with excellent color reproducibility. Is.
[0153]
Further, according to the present invention, an image carrier, a charging unit for charging the image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the charged image carrier, and an image carrier are formed. Developing means for developing the electrostatic latent image with a developer to form a toner image, transfer means for transferring the formed toner image from the image carrier to a transfer material, and transferring an unfixed toner image on the transfer material In an image forming apparatus having fixing means for fixing to a material, when the dry toner is used as a developer, a high image density and clear image can be formed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an apparatus for measuring the triboelectric charge amount of toner.
[Explanation of symbols]
1 Suction machine
2 Measuring device
3 screens
4 lids
5 Vacuum gauge
6 Air volume control valve
7 Suction port
8 capacitors
9 Electrometer

Claims (13)

A dry toner having at least toner particles containing a binder resin, a colorant, a wax component, and a charge control agent,
The colorant includes at least a surface-treated quinacridone pigment and a soluble azo pigment surface-treated with polyethylene wax, and the total content of the quinacridone pigment and the soluble azo pigment in the toner particles is 1 to 20% by mass. The mass ratio of the content of the quinacridone pigment and the soluble azo pigment is 10:90 to 50:50,
The melting point of the wax component is 40 to 130 ° C.,
In addition, the circle equivalent number average diameter measured by the flow type particle image measuring apparatus is 2 to 10 μm, the average circularity is 0.940 to 0.995, and the circularity standard deviation is less than 0.040. Dry toner. The dry toner according to claim 1, wherein the charge control agent is a dialkyl salicylic acid derivative. The dry toner according to claim 1, wherein the charge control agent is a sulfur-containing polymer. The dry toner according to claim 3 , wherein the sulfur-containing polymer is a polymer having a sulfonic acid group. Wherein an average circularity of 0.955 to 0.995, a dry toner according to any one of claims 1 to 4 wherein the circularity standard deviation is equal to or less than 0.035. In the average circularity of from 0.970 to 0.990, a dry toner according to any one of claims 1 to 5 wherein the circularity standard deviation is equal to or less than 0.015 than 0.035 . Dry toner according to any one of claims 1 to 6 Toner particles less than circularity 0.950 is equal to or more than 15% by number. Dry toner according to any one of claims 1 to 7 wherein the quinacridone pigment is characterized in that it is a pigment represented by the following general formula [1].

Dry toner according to any one of claims 1 to 8 wherein the soluble azo pigment is characterized in that it is a pigment represented by the following general formula [2].

The quinacridone pigment is C.I. I. Pigment Red 122, C.I. I. Pigment Red 202, and C.I. I. Dry toner according to any one of claims 1 to 9, characterized in that any one selected from the group of Pigment Violet 19. The soluble azo pigment is C.I. I. Pigment Red 48: 2, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 58: 2, and C.I. I. The dry toner according to any one of claims 1 to 10 , wherein the dry toner is selected from the group of Pigment Red 64 . Dry toner according to any one of claims 1 to 11, wherein the magenta toner used in full color image formation. Image carrier, charging means for charging image carrier, electrostatic latent image forming means for forming electrostatic latent image on charged image carrier, and electrostatic latent image formed on image carrier as developer Developing means for forming a toner image by developing, a transfer means for transferring the formed toner image from the image carrier to the transfer material, and a fixing means for fixing the unfixed toner image on the transfer material to the transfer material. In an image forming apparatus having
The developer, an image forming apparatus which is a dry toner according to any one of claims 1 to 12.

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