JP2004341397A - Toner and method for manufacturing the toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner having high coloring power, ensuring low toner consumption, free of fogging and scattering because of good chargeability, and having good transferability. <P>SOLUTION: The toner contains a styrene polymer or a styrene-acrylic acid derivative copolymer as a binder resin, a Cu phthalocyanine derivative whose solubility in styrene at 25°C is ≤5 mass%, and carbon black or a Cu phthalocyanine pigment as a colorant, wherein toner particles whose circularity is <0.950 occupy 1-30% and a standard deviation of circularity is 0.010-0.040. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４７】
円形度標準偏差ＳＤｃは、上記式（１）及び（２）で求めた平均円形度をｃ_ａｖ、各粒子における円形度をｃ_ｉ、測定粒子数をｍとすると、下記式（３）から算出される。
【００４８】
【数２】

【００４９】
ここで、「粒子像と同じ投影面積」とは二値化されたトナー粒子像の面積であり、「粒子の投影像の周囲長」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。
【００５０】
尚、本発明で測定装置として用いられる「ＦＰＩＡ−１０００」は、各粒子の円形度を算出後、平均円形度及び円形度標準偏差の算出に当たって、粒子を得られた円形度によって、円形度０．４００〜１．０００を０．０１０間隔で０．４００以上０．４１０未満、０．４１０以上０．４２０未満…０．９９０以上１．０００未満及び１．０００の如くに６１分割した分割範囲に分け、分割点の中心値と頻度を用いて平均円形度及び円形度標準偏差の算出を行う算出法を用いている。
【００５１】
この算出法で算出される平均円形度及び円形度標準偏差の各値と、上述した各粒子の円形度を直接用いる算出式によって算出される平均円形度及び円形度標準偏差の各値との誤差は、非常に少なく、実質的には無視できる程度であるため、本発明においては、算出時間の短絡化や算出演算式の簡略化の如きデータの取り扱い上の理由で、上述した各粒子の円形度を直接用いる算出式の概念を利用し、一部変更したこの様な算出法を用いている。
【００５２】
本発明における円形度は、粒子の凹凸の度合いを示す指標であり、粒子が完全な球形の場合に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。
【００５３】
また、円相当径とは、円相当径＝（粒子投影面積／π）^１／２×２と定義される値であり、円相当個数平均径（Ｄ１）とは、個数基準によるトナーの円相当径の平均値を表し、粒度分布の分割点ｉでの粒径（中心値）をｄ_ｉ、頻度をｆ_ｉとすると下式の如く表される。
【００５４】
【数３】

【００５５】
本発明における粒度分布の分割点は、下表に示されるとおりである。
【００５６】
【表１】

【００５７】
具体的な測定方法としては、容器中に予め不純固形物などを除去したイオン交換水１０ｍｌを用意し、その中に分散剤として界面活性剤、好ましくはアルキルベンゼンスルホン酸塩を加えた後、さらに測定試料を０．０２ｇ加え、均一に分散させる。分散させる手段としては、超音波分散機「ＵＨ−５０型」（エスエムテー社製）に振動子として直径５ｍｍのチタン合金チップを装着したものを用い、５分間分散処理を用い、測定用の分散液とする。その際、該分散液の温度が４０℃以上とならない様に適宜冷却する。
【００５８】
トナーの形状測定には、前記フロー式粒子像測定装置を用い、測定時のトナー粒子濃度が３０００〜１万個／μｌとなる様に該分散液濃度を再調整し、トナー粒子を１０００個以上計測する。計測後、このデータを用いて、トナーの円形度０．９５０未満のトナー粒子の存在割合及び円形度標準偏差を求める。
【００５９】
本発明は、用いるＣｕフタロシアニン誘導体の色相等を勘案し、ブラックトナーやシアントナーに好ましく適用することができる。これらの中でも特に、カーボンブラックを着色剤とするブラックトナーやＣｕフタロシアニン顔料を着色剤とするシアントナーに好ましく適用することができる。
【００６０】
先ず、カーボンブラックについて説明する。
【００６１】
本発明に用いられるカーボンブラックとしては、平均一次粒径が２５〜１２０ｎｍであるものが好ましい。平均一次粒径が２５ｎｍ未満のカーボンブラックは、本発明にかかるＣｕフタロシアニン誘導体と併用しても、カーボンブラックの凝集が強くなりすぎ、トナー中に均一に分散させることが困難となる。また、平均一次粒径が１２０ｎｍを超えるカーボンブラックは、良好に分散しても十分な着色力を得ることができず、十分な着色力を得るまでカーボンブラックを使用するとトナーの帯電性が低下しカブリを引き起こす。
【００６２】
本発明に用いるカーボンブラックの平均一次粒径の測定方法は、透過型顕微鏡で３０，０００倍の倍率で断面の拡大写真をとり、カーボンブラックの粒子１００個分の平均値を算出して求める。
【００６３】
さらに、本発明に用いるカーボンブラックのＤＢＰ吸油量は、好ましくは２０〜１８０ｍｌ／１００ｇ、さらに好ましくは３０〜１６０ｍｌ／１００ｇであることが良い。
【００６４】
本発明に好ましく用いられるカーボンブラックは、通常のトナーに使用されているものよりも比表面積が小さく、且つ揮発分が少ないものである。比表面積が小さく、揮発分が少ないカーボンブラックは、重合阻害性の官能基が少ないことから、懸濁重合でトナーを製造する場合、重合阻害性が低い利点がある。
【００６５】
よって、本発明に用いられるカーボンブラックは、窒素吸着による比表面積が１００ｍ^２／ｇ以下、好ましくは３０〜９０ｍ^２／ｇ、さらに好ましくは４０〜９０ｍ^２／ｇであることが良く、さらに、揮発分が２質量％以下、好ましくは０．１〜１．８質量％、より好ましくは０．１〜１．７質量％であることが良い。
【００６６】
尚、本発明に用いられるカーボンブラックのＤＢＰ吸油量、比表面積、揮発分の測定を以下に記す。
【００６７】
（１）カーボンブラックのＤＢＰ吸油量の測定は「ＪＩＳ ４６５６／１」に準じて測定する。
【００６８】
（２）カーボンブラックの窒素吸着による比表面積の測定は「ＪＩＳ ４６５２」に準じて測定する。
【００６９】
（３）カーボンブラックの揮発分の測定は「ＪＩＳ １１２６」に準じて測定する。
【００７０】
また、本発明のトナーには着色剤として、磁性粉を単独、またはカーボンブラックと併用して用いても良い。具体的には、マグネタイト、ヘマタイト、フェライトの如き酸化鉄；鉄、コバルト、ニッケルのような金属或いはこれらの金属とアルミニウム、コバルト、銅、鉛、マグネシウム、スズ、亜鉛、アンチモン、ベリリウム、ビスマス、カドミウム、カルシウム、マンガン、セレン、チタン、タングステン、バナジウムのような金属の合金及びその混合物等の強磁性体が挙げられる。
【００７１】
これらの磁性粉は個数平均粒径が０．０５〜２μｍ、好ましくは０．１〜０．５μｍのものが好ましく、トナー粒子中への含有量としては結着樹脂を含む樹脂成分１００質量部に対して約２０〜２００質量部、特に好ましくは４０〜１５０質量部が良い。
【００７２】
また、上記磁性粉は、１０ＫＯｅ印加での磁気特性が抗磁力２０〜１５０エルステット（Ｏｅ）、飽和磁化５０〜２００ｅｍｕ／ｇ、及び残留磁化２〜２０ｅｍｕ／ｇのものが好ましい。
【００７３】
次にＣｕフタロシアニン顔料について説明する。
【００７４】
本発明に用いられるＣｕフタロシアニン顔料としては遊離Ｃｕの含有率が１０〜２０００ｐｐｍであることが好ましい。詳細は不明であるが、Ｃｕフタロシアニン顔料中に存在する遊離Ｃｕを特定することで、Ｃｕフタロシアニン誘導体との相互作用により、着色剤の分散性を一層高めることができる。
【００７５】
遊離Ｃｕの含有率が１０ｐｐｍ未満の場合、Ｃｕフタロシアニン顔料は十分に発色しない着色剤となってしまうため、着色力が劣ったものになる。遊離Ｃｕの含有率が２０００ｐｐｍを超えると、遊離ＣｕによりＣｕフタロシアニン顔料の分散性が悪化する傾向がある。
【００７６】
Ｃｕフタロシアニン顔料は、通常、フタル酸またはフタル酸誘導体、尿素または尿素誘導体及びＣｕ化合物をモリブデン化合物等のフタロシアニン化触媒の存在下に不活性有機溶媒中で加熱し、粗製Ｃｕフタロシアニンを得た後、これを微細化する顔料化工程を経て製造される。本発明において用いられる遊離Ｃｕの含有率が１０〜２０００ｐｐｍのＣｕフタロシアニン顔料は、上記Ｃｕフタロシアニンの製造方法において、加熱反応終了後、反応生成物から溶媒を減圧留去し、得られた残留物を水で十分に洗浄したり、或いは、粗製Ｃｕフタロシアニンを得た後、これを微細化する顔料化工程において水や酸で十分に洗浄したりすることによって得ることができ、両工程において十分に洗浄することが好ましい。例えば、上記Ｃｕフタロシアニンの製造方法において、加熱反応終了後、反応生成物から溶媒を減圧留去し、得られた残留物を水で洗浄した遊離Ｃｕの含有率を１２０００ｐｐｍ程度にまで減らした後、ソルベントソルトミリング法またはアシッドペースティング法による顔料化の水洗工程、ドライミリング法による顔料化の酸洗工程を経ることにより最終的に得られる顔料中の遊離Ｃｕの含有率を１０〜２０００ｐｐｍにすることができる。また、遊離Ｃｕの含有率をさらに小さくするために、上記残留物を希硫酸等を用いて酸洗浄を行う方法、通常使用するモリブデン化合物触媒の他に、ルテニウム化合物及び／またはオスミウム化合物の微量を反応系に添加する方法等を用いてもよい。
【００７７】
遊離Ｃｕの含有率は、次のようにして求める。Ｃｕフタロシアニン試料３．０ｇを精秤したのち、硫酸３０．０ｇを加えて溶解後、冷水１５０ｍｌに加えて、９０℃に保って３０分間攪拌する。次に、沈殿物を濾過し、得られたウェットケーキを熱水で洗浄液が中性になるまで洗浄する。濾液及び洗浄液中の遊離Ｃｕを原子吸光法により求める。
【００７８】
他の有彩色トナー用着色剤としてイエロー及びマゼンタトナー着色剤に使用することができる。
【００７９】
本発明に用いられるイエロー着色剤としては、縮合アゾ化合物、イソインドリノン化合物、アンスラキノン化合物、アゾ金属錯体、メチン化合物、アリルアミド化合物に代表される化合物が用いられる。具体的には、例えば、Ｃ．Ｉ．ピグメントイエロー１２〜１５、１７、６２、７４、８３、９３〜９５、９７、１０９、１１０、１１１、１２０、１２７〜１２９、１４７、１５５、１６８、１７４、１７６、１８０、１８１、１９１が好適に用いられる。
【００８０】
本発明に用いられるマゼンタ着色剤としては、縮合アゾ化合物、ジケトピロロピロール化合物、アンスラキノン、キナクリドン化合物、塩基染料レーキ化合物、ナフトール化合物、ベンズイミダゾロン化合物、チオインジゴ化合物、ペリレン化合物が用いられる。具体的には、例えば、Ｃ．Ｉ．ピグメントレッド２、３、５、６、７、２３、４８：２、４８：３、４８：４、５７：１、８１：１、１４４、１４６、１６６、１６９、１７７、１８４、１８５、２０２、２０６、２２０、２２１、２５４を用いることが特に好ましい。
【００８１】
これらの着色剤は、単独または混合して使用することができ、さらには、固溶体の状態で用いることもできる。
【００８２】
本発明のトナーには、ワックス成分を使用することも好ましい形態である。
本発明のトナーに用いるワックスとしては融点が５０〜１２０℃のものが好ましい。懸濁重合でトナーを製造する場合、ワックスの融点が上記範囲であるとき、造粒工程でのトナー粒子は適度な粘度を持っており、Ｃｕフタロシアニン誘導体はトナー中に良好な状態で存在する。そのためトナーの帯電性が一層良好なものとなる。ワックスの融点が上記に示した融点の値を外れた場合、或いはワックスを添加しない場合、Ｃｕフタロシアニン誘導体の分散性が悪化し、カブリ、飛び散りが悪くなる傾向にある。
【００８３】
本発明に用いられるワックス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、ペトロラク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或いはその化合物；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、もしくは併せて用いることができる。
【００８４】
これらの中でも、ポリオレフィン、フィッシャートロプシュ法による炭化水素ワックス、石油系ワックス、高級アルコール、若しくは、高級エステルを使用した場合に、現像性や転写性の改善効果がさらに高くなる。尚、これらのワックス成分には、トナーの帯電性に影響を与えない範囲で酸化防止剤が添加されていてもよい。また、これらのワックス成分は、結着樹脂１００質量部に対して１〜３０質量部使用するのが好ましい。
【００８５】
本発明で用いられるワックス成分は、ゲルパーミエーションクロマトグラフィ（ＧＰＣ）により測定された分子量分布において、数平均分子量（Ｍｎ）が２００〜２０００で、Ｍｗ／Ｍｎが３．０以下であるものが好ましい。該ワックス成分のＭｎが２００未満であると低分子量成分の比率が多くなり、結果としてトナーの帯電性や画像形成装置とのマッチングに問題を生じるため好ましくない。また、Ｍｎが２０００を超える場合、或いはＭｗ／Ｍｎが３．０を超える場合には、定着画像表面を適度に平滑化させることが困難となり、混色性低下の点から好ましくなく、また、重合法によりトナー粒子を得る際に、水系分散媒体中で造粒・重合を行なうため、主に造粒中にワックス成分が析出してくるので好ましくない。
【００８６】
上記ワックス成分の分子量分布はＧＰＣによって以下の条件で測定される。
【００８７】
〈ＧＰＣ測定条件〉
装置：ＧＰＣ−１５０Ｃ（ウォーターズ社製）
カラム：ＧＭＨ−ＨＴ（東ソー社製）の２連
温度：１３５℃
溶媒：ｏ−ジクロロベンゼン（０．１％アイオノール添加）
流速：１．０ｍｌ／ｍｉｎ
試料：濃度０．１５質量％の試料を０．４ｍｌ注入
以上の条件で測定し、試料の分子量算出にあたっては単分散ポリスチレン標準試料により作成した分子量校正曲線を使用し、Ｍａｒｋ−Ｈｏｕｗｉｎｋ粘度式から導き出される換算式でポリエチレン換算することによって求める。
【００８８】
本発明のトナーにおいてはＣｕフタロシアニン誘導体に帯電制御剤としての効果があるが必要に応じて他の帯電制御剤を併用してもよい。併用できる帯電制御剤としては例えば、ネガ系帯電制御剤としてサリチル酸、ナフトエ酸、ジカルボン酸の如き芳香族カルボン酸の金属化合物；スルホン酸またはカルボン酸基を側鎖に持つ高分子型化合物；ホウ素化合物；尿素化合物；ケイ素化合物；カリークスアレーンが挙げられる。ポジ系帯電制御剤として、四級アンモニウム塩；該四級アンモニウム塩を側鎖に有する高分子型化合物；グアニジン化合物；イミダゾール化合物が挙げられる。
【００８９】
また、別の帯電制御剤としては樹脂タイプのものも好ましい形態である。樹脂タイプのものとしては、例えば、スルホン酸基を有する重合体がより好ましい。本発明のトナーに好適に用いられるスルホン酸基を有する重合体としては、側鎖にスルホン酸基を有する高分子型化合物等が挙げられ、特にスルホン酸基含有モノマーを共重合比で１〜１０質量％含有し、スチレン及び／またはスチレン（メタ）アクリル酸エステル共重合体である高分子型化合物を用いた場合、好ましい帯電特性を享受することができる。モノマー比が１質量％未満の場合、トナー中の着色剤はトナーの内部の方へ偏在する傾向があり、トナーの表面が柔らかくなりやすい。また１０質量％を超えると、着色剤はトナーの表面の方へ偏在しやすくなり、トナー表面が硬くなりやすい。
【００９０】
例えばトナーを懸濁重合法で製造する場合、スルホン酸基を有する重合体として、（メタ）アクリルアミド系モノマーを適度に含有する共重合体はトナー表面の着色剤の存在量を容易に制御することが可能である。
【００９１】
上記のスルホン酸基含有（メタ）アクリルアミド系モノマーとしては、下記式（Ａ）で示されるものが好ましく、具体的には、２−アクリルアミド−２−メチルプロパン酸や２−メタクリルアミド−２−メチルプロパン酸等が挙げられる。
【００９２】
【化１】

【００９３】
（上記一般式中、Ｒ_１は水素原子、またはメチル基を示し、Ｒ_２とＲ_３は、それぞれ水素原子、Ｃ_１〜Ｃ_１０のアルキル基、アルケニル基、アリール基、またはアルコキシ基を示し、ｎは１〜１０の整数を示す。）
【００９４】
上記スルホン酸基を含有する重合体は、トナー製造時にアルカリ金属及び／またはアルカリ土類金属を含有する無機化合物を添加することによって、スルホン酸基の部分に塩構造が形成されるので、特に上記の如きスルホン酸基含有（メタ）アクリルアミド系モノマーを用いた高分子型化合物の場合、分子内でのスルホベタイン構造の生成が抑制され、水和を防止しながら本発明の着色剤との相互作用を確保することができるので、環境変動に対するトナーの帯電性が一層良好なものとなる。特に、懸濁重合法によってトナーを製造する際、後述するようなアルカリ金属及び／またはアルカリ土類金属を含有する分散安定剤を用いると、スルホン酸基との塩構造を容易に形成することができるので好ましい。
【００９５】
上記の如きスルホン酸基と塩構造を形成し得るアルカリ金属、もしくはアルカリ土類金属としては、例えば、リチウム、ナトリウム、カリウム、カルシウム、バリウム、ベリリウム、マグネシウム等が挙げられ、中でもカルシウムが好ましい。
【００９６】
本発明のトナーを重合法で製造する場合、前述した樹脂も併用することが可能であるが、帯電付与の観点から特にポリエステル樹脂（以下、「極性樹脂」と称す。）を添加することが好ましい。トナー中に極性樹脂を添加することによって、トナー中の着色剤がトナー表面近傍に偏在するのを防ぐことが可能である。また、極性樹脂の存在により、水系媒体中でトナーを重合する際に、Ｃｕフタロシアニン誘導体が水系媒体中に溶出するのを防ぐことが可能である。例えば、後述する懸濁重合法により直接トナーを製造する場合には、上記の如き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、トナー中の着色剤は良好な分散状態を維持しつつ、トナー表面には偏在しない状態となる。特に酸価が１〜２０ｍｇＫＯＨ／ｇを呈する極性樹脂を用いると上記に記したような着色剤の分散状態を実現することが容易となる。
【００９７】
上記極性樹脂の添加量は、Ｃｕフタロシアニン誘導体の効果が消失しないように、上記特定の結着樹脂１００質量部に対して２５質量部以下で使用するのが好ましく、より好ましくは１５質量部以下である。
【００９８】
係る極性樹脂として用いられる代表的なポリエステル樹脂としては、アルコール成分として、エチレングリコール、プロピレングリコール、１，３−ブタンジオール、１，４−ブタンジール、２，３−ブタンジオール、ジエチレングリコール、トリエチレングリコール、１，５−ペンタンジオール、１，６−ヘキサンジオール、ネオペンチルグリコール、２−エチル１，３−ヘキサンジオール、水素化ビスフェノールＡ、下記式（Ｂ）で表わされるビスフェノール誘導体及び下記式（Ｃ）で示されるジオール類を用いたポリエステル樹脂が挙げられる。
【００９９】
【化２】

【０１００】
（式中、Ｒはエチレンまたはプロピレン基を示し、ｘ及びｙはそれぞれ１以上の整数であり、且つｘ＋ｙの平均値は２〜１０である。）
【０１０１】
【化３】

【０１０２】
特に好ましいポリエステル樹脂のアルコール成分としては、前記式（Ｂ）で示されるビスフェノール誘導体であり、酸成分としては、フタル酸、テレフタル酸、イソフタル酸、トリメリット酸またはその無水物類が挙げられる。
【０１０３】
酸成分としては、フタル酸、テレフタル酸、イソフタル酸、無水フタル酸の如きベンゼンジカルボン酸類またはその無水物；コハク酸、アジピン酸、セバシン酸、アゼライン酸の如きアルキルジカルボン酸類またはその無水物等が挙げられる。また、トリメリット酸、ピロメリット酸、ベンゾフェノンテトラカルボン酸やその無水物の如き多価カルボン酸を用いることもできる。
【０１０４】
また、極性樹脂として反応性ポリエステル樹脂やポリカーボネート樹脂を用いた場合には、トナーの帯電特性が向上し、画像カブリや飛び散りが改善されると共に、ドット再現性に優れる高品位な画像を得ることができる。また、トナー粒子に適度な機械的強度を付与することが可能となり、画像形成装置から受けるトナー劣化の影響を最小限にとどめ、多数枚プリントアウトに対する耐久性や画像形成装置とのマッチングも向上する。さらには、前述の如きトナーの形状分布を達成するためのトナーの球形化処理や重合法によってトナーを直接製造する際の乾燥処理等のトナー製造工程から受ける影響を最小限とすることができる。また、極性樹脂は２種類以上を組み合わせて用いることも可能で、それ自身の有する帯電性を利用することもできる。
【０１０５】
本発明で使用できるポリエステル樹脂は、あまり分子量が低すぎるとトナー表面が柔らかくなるため、耐ブロッキング性が低下することがある。逆に、あまり高分子量であると、例えば重合法によりトナーを得る場合には、重合性単量体への該ポリエステル樹脂の溶解が困難となるため、製造が困難となる。従って、反応性ポリエステル樹脂の重量平均分子量は、３，０００〜１００，０００の範囲にあるものが特に性能の優れたトナーを得るのに好適である。
【０１０６】
本発明のトナーに無機微粉体を添加することは、現像性、転写性、帯電安定性、流動性及び耐久性向上のために好ましい実施形態である。該無機微粉体としては公知のものが使用可能であるが、シリカ、アルミナ、チタニア或いはその酸化物の中から選ばれることが好ましい。中でも、シリカであることがより好ましい。シリカはケイ素ハロゲン化物やアルコキシドの蒸気相酸化により生成されたいわゆる乾式法またはヒュームドシリカと称される乾式シリカ、及びアルコキシド、水ガラス等から製造されるいわゆる湿式シリカの両者が使用可能であるが、表面及びシリカ微粉体の内部にあるシラノール基が少なく、またＮａ_２Ｏ、ＳＯ_３ ^２−等の製造残渣の少ない乾式シリカの方が好ましい。また乾式シリカにおいては、製造工程において例えば、塩化アルミニウム、塩化チタン等他の金属ハロゲン化合物をケイ素ハロゲン化合物と共に用いることによって、シリカと他の金属酸化物の複合微粉体を得ることも可能でありそれらも包含する。
【０１０７】
本発明に用いられる無機微粉体は、ＢＥＴ法で測定した窒素吸着による比表面積が３０ｍ^２／ｇ以上、特に５０〜４００ｍ^２／ｇの範囲のものが良好な結果を与え、トナー１００質量部に対して０．３〜８質量部使用され、好ましくは０．５〜５質量部である。
【０１０８】
上記の如きＢＥＴ比表面積が制御された無機微粉体を、トナー表面近傍に存在するＣｕフタロシアニン誘導体と共存させることにより、トナー粒子への水分吸着量の制御がなされ、摩擦帯電量や帯電速度の制御効果が増大する。また、トナー表面に露出した着色剤を適度に被覆し、帯電特性において着色剤の悪影響を抑制することが可能となる。
【０１０９】
さらに、トナーに適度な流動性が付与されるので、トナーの均一帯電性が相乗的に良化し、連続で多数枚プリントアウトを繰り返しても優れた効果が維持される。
【０１１０】
上記無機微粉体のＢＥＴ比表面積が３０ｍ^２／ｇ未満の場合には、トナーに適度な流動性を付与することが困難である。ＢＥＴ比表面積が４００ｍ^２／ｇを超える場合には、連続プリントアウト時に該無機微粉体がトナー粒子表面に埋め込まれるために、トナーの流動性が低下する場合がある。
【０１１１】
尚、上記無機微粉体の比表面積の測定は、比表面積測定装置「オートソーブ１」（湯浅アイオニクス社製）を用いて試料表面に窒素ガスを吸着させ、ＢＥＴ多点法により比表面積を算出する。
【０１１２】
また、無機微粉体の添加量がトナー粒子１００質量部に対して、０．３質量部未満の場合には、添加効果が発現されず、また、８質量部を超えると、トナーの帯電性や定着性に問題を生じるだけでなく、遊離した無機微粉体により画像形成装置とのマッチングが著しく悪化する。
【０１１３】
また、本発明に用いられる無機微粉体は、必要に応じ、疎水化、帯電性制御等の目的でシリコーンワニス、各種変性シリコーンワニス、シリコーンオイル、各種変性シリコーンオイル、シランカップリング剤、官能基を有するシランカップリング剤、その他有機ケイ素化合物、有機チタン化合物の如き処理剤で、或いは、種々の処理剤を併用して処理されていることも可能であり好ましい。
【０１１４】
さらに、高い帯電量を維持し、高転写率を達成するためには、無機微粉体は少なくともシリコーンオイルで処理されることが好ましい。
【０１１５】
本発明のトナーにおいては、実質的な悪影響を与えない範囲内でさらに他の添加剤、例えばテフロン（登録商標）粉末、ステアリン酸亜鉛粉末、ポリフッ化ビニリデン粉末の如き滑剤粉末；酸化セリウム粉末、炭化ケイ素粉末、チタン酸ストロンチウム粉末の如き研磨剤；例えば酸化チタン粉末、酸化アルミニウム粉末の如き流動性付与剤；ケーキング防止剤、或いは例えばカーボンブラック粉末、酸化亜鉛粉末、酸化スズ粉末の如き導電性付与剤、また、逆極性の有機微粒子及び無機微粒子を現像性向上剤として少量用いることもできる。
【０１１６】
本発明のトナーは、そのまま一成分系現像剤として、或いは、キャリアと混合して二成分系現像剤として使用することができる。
【０１１７】
二成分系現像剤として用いる場合、例えば、トナーと混合させる磁性キャリアとしては、鉄、銅、亜鉛、ニッケル、コバルト、マンガン、クロムより選ばれる元素を単独で、または複数含有するフェライト状態で構成される。磁性キャリアの形状は、球状、扁平、不定形のいずれも用いることができ、さらに、表面状態の微細構造（例えば、表面凹凸性）を適宜に制御したものを用いることもできる。また、表面を樹脂で被覆した樹脂被覆キャリアや磁性体分散型樹脂キャリアも好適に用いることができる。使用するキャリアの平均粒径は、好ましくは１０〜１００μｍ、より好ましくは２０〜５０μｍである。また、これらのキャリアとトナーを混合して二成分系現像剤を調製する場合の現像剤中のトナー濃度は、好ましくは２〜１５質量％程度である。
【０１１８】
［トナーの製造方法］
本発明のトナーの製造方法は少なくとも、重合性ビニル系単量体、着色剤、重合開始剤、及びＣｕフタロシアニン誘導体を含有する重合性単量体組成物を水系分散媒体中に分散して該重合性単量体組成物の粒子を生成する造粒工程と
該重合性単量体組成物の粒子中の重合性ビニル系単量体を重合してトナー粒子を生成する重合工程とを有し、
該重合性ビニル系単量体は少なくともスチレンを含有し、
該Ｃｕフタロシアニン誘導体の２５℃におけるスチレンへの溶解度が５質量％以上であって、
前記造粒工程から重合工程に至る重合性ビニル系単量体の重合反応を、少なくとも水系分散媒体のｐＨを４．５〜９．０に保持しながら行うことが必須である。
【０１１９】
本発明のトナーの製造方法において、水系媒体のｐＨが４．５未満の場合、造粒工程で粒子を作る上で必要な分散剤が十分に効かず、所望の形状のトナーを得ることができない。また、ｐＨが９．０を超える場合、Ｃｕフタロシアニン誘導体が水系媒体中に溶出し、所望の形状のトナーを得ることができないばかりか、トナーの帯電性も悪化する。
【０１２０】
尚、重合工程で重合性ビニル系単量体の重合転化率が８０％以上になれば、トナーの形状や、内部の状態は維持されるので必要に応じて水系媒体のｐＨを４．５未満或いは９．０を超えるように再調整してもよい。
【０１２１】
本発明において、重合性ビニル系単量体の「重合転化率」とは、前記重合性単量体組成物に用いられる重合性ビニル系単量体の総質量（Ｗ_１）を基準として、未反応の重合性ビニル系単量体の総質量（Ｗ_２）を定量することにより下記の式から求められる。
【０１２２】
重合転化率（％）＝｛（Ｗ_１−Ｗ_２）／Ｗ_１｝×１００
【０１２３】
また、未反応の重合性ビニル系単量体の質量は、反応容器からサンプリングした直後に、重合停止剤や冷メタノール等を採取サンプルに添加して重合反応を停止させ、▲１▼熱天秤等により加熱時の重量減少量として測定する熱重量測定（ＴＧ）を用いる方法、▲２▼ガスクロマトグラフィー（ＧＣ）を用いる方法等の公知の方法を適用することにより定量することができる。これらの中でもＧＣを用いる方法は、特に有効な方法である。
【０１２４】
本発明のトナーの製造方法において、水系媒体として、公知の無機系及び有機系の分散剤を用いた水系分散媒体を用いることができる。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。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、デンプンを用いることができる。
【０１２５】
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。
【０１２６】
本発明のトナーの製造方法においては、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、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２００〜３，０００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。
【０１２７】
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。
【０１２８】
本発明のトナーの製造方法に用いる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また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。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０．１〜２０質量部用いられる。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、単独または混合して使用される。
【０１２９】
重合性単量体組成物中には、重合度を制御するため、公知の連鎖移動剤及び重合禁止剤等をさらに添加し用いてもよい。これらの添加剤は、前記重合性単量体組成物中に予め添加しておくこともできるし、また、必要に応じて、重合反応の途中で適宜に添加することもできる。
【０１３０】
以下に本発明の実施態様を示す。
【０１３１】
〔実施態様１〕
少なくとも、結着樹脂、着色剤、及びＣｕフタロシアニン誘導体を含有するトナーであって、
該結着樹脂は少なくとも、スチレン重合体またはスチレン系共重合体であって、
該Ｃｕフタロシアニン誘導体の２５℃におけるスチレンへの溶解度が５質量％以上であって、
該Ｃｕフタロシアニン誘導体の含有量が着色剤の含有量に対して０．１〜１８％であり、
該トナーはフロー式粒子像測定装置で計測される円形度０．９５０未満のトナー粒子の存在割合が１〜３０％であり、且つ、円形度標準偏差が０．０１０〜０．０４０であることを特徴とするトナー。
【０１３２】
〔実施態様２〕
実施態様１において、Ｃｕフタロシアニン誘導体がＣ．Ｉ．ソルベントブルー４、１４、２２、２５、３５、４０、４９、５５、６３、７０、７３、７８、８３、８４、８５、８６、９１、９４、９５、１０４、１９４、１９５のいずれかである。
【０１３３】
〔実施態様３〕
実施態様１または２において、着色剤が平均一次粒径２５〜１２０ｎｍであるカーボンブラックである。
【０１３４】
〔実施態様４〕
実施態様１〜３のいずれかにおいて、着色剤が、遊離Ｃｕの含有率が１０〜２０００ｐｐｍであるＣｕフタロシアニン系顔料である。
【０１３５】
〔実施態様５〕
実施態様１〜４のいずれかにおいて、トナーが少なくとも融点５０〜１２０℃のワックス成分を含有している。
【０１３６】
〔実施態様６〕
少なくとも、重合性ビニル系単量体、着色剤、重合開始剤、及びＣｕフタロシアニン誘導体を含有する重合性単量体組成物を水系分散媒体中に分散して該重合性単量体組成物の粒子を生成する造粒工程と、
該重合性単量体組成物の粒子中の重合性ビニル系単量体を重合してトナー粒子を生成する重合工程とを有し、
該重合性単量体は少なくともスチレンを含有し、
該Ｃｕフタロシアニン誘導体の２５℃におけるスチレンへの溶解度が５質量％以上であって、
前記造粒工程から重合工程に至る重合性ビニル系単量体の重合反応が、少なくとも水系分散媒体のｐＨを４．５〜９．０に保持しながら行うことを特徴とするトナーの製造方法。
【０１３７】
〔実施態様７〕
実施態様６において、Ｃｕフタロシアニン誘導体がＣ．Ｉ．ソルベントブルー４、１４、２２、２５、３５、４０、４９、５５、６３、７０、７３、７８、８３、８４、８５、８６、９１、９４、９５、１０４、１９４、１９５のいずれかである。
【０１３８】
【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。
【０１３９】
［実施例１］
四つ口容器中にイオン交換水３６０質量部と０．１ｍｏｌ／ｌのＮａ_３ＰＯ_４水溶液４３０質量部を添加し、高速撹拌装置ホモミキサーを用いて１０，０００ｒｐｍで撹拌しながら、６０℃に保持した。ここに１規定の塩酸を１０質量部添加した後、１．０ｍｏｌ／ｌ−ＣａＣｌ_２水溶液３４質量部を徐々に添加し、微細な難水溶性分散安定剤Ｃａ_３（ＰＯ_４）_２を含む水系分散媒体を調製した。この時の水系媒体のｐＨは５．３であった。
【０１４０】
一方、分散質として、
・スチレンモノマー ８３質量部
・ｎ−ブチルアクリレート １７質量部
・カーボンブラック ８質量部
（平均一次粒径＝４０ｎｍ、ＤＢＰ吸油量＝８０ｍｌ／１００ｇ、ＢＥＴ比表面積＝５５ｍ^２／ｇ、揮発分＝０．７質量％）
・ポリエステル樹脂 ５質量部
（Ｍｗ＝１２００、Ｍｎ＝５７００、酸価＝１０ｍｇＫＯＨ／ｇ）
・Ｃ．Ｉ．ソルベントブルー７０ ０．３質量部
（スチレンへの溶解度：２６質量％）
・ジビニルベンゼン ０．２質量部
・スチレンと２−アクリルアミド−２−メチルプロパン酸（ＡＭＰＳ）の共重合
体 １質量部
（共重合比＝スチレン：ＡＭＰＳ＝９６：４）
・エステルワックス １２質量部
（融点＝６０℃、Ｍｎ＝３５０、Ｍｗ／Ｍｎ＝２．１）
からなる混合物をアトライター（三井金属社製）を用い４時間分散させた後、２，２’−アゾビス（２，４−ジメチルバレロニトリル）３質量部を添加し、重合性単量体組成物を調製した。
【０１４１】
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６０℃のＮ２雰囲気下で、高速撹拌装置の回転数を１０，０００ｒｐｍを維持しつつ、４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、５時間重合を行った。その後８０℃まで昇温し、さらに５時間重合を行った。重合終了後、冷却し、希塩酸を添加して水系分散媒体のｐＨを１．２にして難水溶性分散剤を溶解せしめた。さらに加圧濾過による固液分離の後、２０００質量部の水で洗浄を行った。その後、真空乾燥装置を用いて４５℃で４時間乾燥させ、平均粒径が６．４μｍのブラック色のトナー粒子を得た。
【０１４２】
上記重合体粒子１００質量部と疎水性オイル処理シリカ微粉体（ＢＥＴ比表面積＝２００ｍ^２／ｇ）０．７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、トナーを得た。得られたトナー中の円形度０．９５０未満のトナーの割合、及び円形度標準偏差を表２に示す。
【０１４３】
また、このトナーについて、着色剤の分散状態を評価したところ、非常に良好であった。評価結果を表３に示す。尚、評価方法は以下のようにして行われた。後述の実施例２〜９及び比較例１〜５もこの評価方法に従っている。
【０１４４】
〔着色剤の分散状態の評価〕
透過型顕微鏡（ＴＥＭ）で１２，０００倍の倍率でトナーの断面の拡大写真をとり、トナー中の着色剤の分散状態を観察した。評価基準は以下の通りである。
Ａ：非常に良好。
Ｂ：若干の凝集は見られるが概ね良好に分散。
Ｃ：分散した着色剤と凝集した着色剤が混在。
Ｄ：着色剤は完全に凝集しており、着色剤が含有されていないトナー粒子も存在。
【０１４５】
次に１万枚のプリントアウト画像評価を行った。画像形成装置として図１に示すようなレーザービームプリンタ（キヤノン製）を用意した。図中、１は感光体、２はトナー担持体、３は転写材、４は現像剤、５は帯電ローラー、６はブレードである。この装置を改造し、プロセススピードが１５０ｍｍ／ｓとなるように変更した。図１に示すように、この装置は直流及び交流成分を印加した帯電ローラー５を用い感光体１を一様に帯電する。このとき、直流成分は定電圧に制御し、交流成分は定電流に制御する。帯電に次いで、レーザー光で画像部分を露光することにより静電潜像を形成し、現像剤４により可視画像としてトナー画像を形成した後、電圧を印加した転写ローラーによりトナー画像を転写材３に転写するプロセスを持つ。
【０１４６】
現像剤４として上記によって製造されたトナーを用い、以下の現像条件を満足するようプロセス条件を設定した。
【０１４７】
感光体暗部電位 −７００Ｖ
感光体明部電位 −１５０Ｖ
現像バイアスは直流成分のみで−１００〜−９００Ｖの範囲で、初期の画像濃度が１．５０となるように設定し、その後、千枚おきに画像濃度が１．５０となるように再調整してプリントアウト評価を行った。
【０１４８】
プリントアウト評価は常温常湿下において、Ａ４サイズ紙に面積比率４％印字の画像パターンで、１万枚の連続プリントアウト試験を行い、初期、５千枚、及び１万枚時の画像評価を行った。その結果、トナー消費量、画像濃度、画像カブリ、飛び散り、転写性何れにおいても良好であり、初期と同等の画像品質を得た。評価結果を表３に示す。
【０１４９】
評価方法は次の通りであり、後述の実施例２〜９及び比較例１〜５もこの評価方法に従っている。
【０１５０】
〔トナー消費量〕
初期から１万枚のプリントアウト評価を行った際に消費したトナー量を示す。
Ａ：２５０ｇ未満
Ｂ：２５０ｇ以上、３００ｇ未満
Ｃ：３００ｇ以上、３５０ｇ未満
Ｄ：３５０ｇ以上
【０１５１】
〔画像濃度〕
通常の複写機用普通紙（７５ｇ／ｍ^２）に一辺が５ｍｍの正方向のベタ黒画像をプリントアウトし、「マクベス反射濃度計 ＲＤ９１８」（マクベス社製）を用いて、原稿濃度が０．００の白地部分のプリントアウト画像に対する相対濃度を測定した。
Ａ：１．４０以上
Ｂ：１．３０以上、１．４０未満
Ｃ：１．００以上、１．３０未満
Ｄ：１．００未満
【０１５２】
〔画像カブリ〕
ベタ白画像形成時の感光体上の現像−転写間のトナーをマイラーテープによってテーピングして剥ぎ取り、それを紙上に貼ったものの反射濃度を「マクベス反射濃度計 ＲＤ９１８」で測定する。得られた反射濃度から、マイラーテープをそのまま紙上に貼った時の反射濃度を差し引いた数値を用いて評価した。数値が小さいほど、画像カブリが抑制されていることになる。
Ａ：０．０３未満
Ｂ：０．０３以上、０．０７未満
Ｃ：０．０７以上、０．１５未満
Ｄ：０．１５以上
【０１５３】
〔画像飛び散り〕
グラフィカルな画像の画質に関わる微細な細線での飛び散り評価であり、文字画像よりも飛び散り易い１ドットライン画像を普通紙（７５ｇ／ｃｍ^２）にプリントアウトした際のライン画像の再現性と周辺部へのトナーの飛び散りを目視で評価した。
Ａ：ほとんど発生せず、良好なライン再現性を示す。
Ｂ：軽微な飛び散りが見られる。
Ｃ：若干の飛び散りが見られるが、ライン再現性に対する影響は少ない。
Ｄ：顕著な中抜けが見られる。
【０１５４】
〔転写性〕
ベタ黒画像形成時の感光体上の転写残余のトナーをマイラーテープによってテーピングして剥ぎ取り、それを紙上に貼ったものの反射濃度を「マグベス反射濃度計 ＲＤ９１８」で測定する。得られた反射濃度から、マイラーテープをそのまま紙上に貼った時の反射濃度を差し引いた数値を用いて評価した。数値が小さい程、転写性が良好であることになる。
Ａ：０．０３未満
Ｂ：０．０３以上、０．０７未満
Ｃ：０．０７以上、０．１０未満
Ｄ：０．１０以上
【０１５５】
［実施例２］
実施例１において重合性ビニル系単量体として、スチレン８３質量部とｎ−ブチルアクリレート１７質量部をスチレン１００質量部に変えて、またＣ．Ｉ．ソルベントブルー７０の添加量を０．０３質量部に変えて重合を行った。さらに重合工程において重合転化率が９２％になった段階で、水系媒体中に炭酸ナトリウムを添加してｐＨを９．５に変更した。それ以外は実施例１と同様にして行い、平均粒径が６．８μｍのブラック色のトナーを得た。このトナーについて実施例１と同様の評価を行った。その結果、概ね良好な結果が得られた。評価結果を表３に示す。
【０１５６】
［実施例３］
実施例１において、ワックスを融点が４０℃のエステルワックスに変更し、Ｃ．Ｉ．ソルベントブルー７０の添加量を０．７質量部に変えて、実施例１と同様にして行い、平均粒径が６．５μｍのブラック色のトナーを得た。このトナーについて実施例１と同様に評価したところ、概ね良好な結果が得られた。評価結果を表３に示す。
【０１５７】
［実施例４］
実施例１において、ワックスを融点が１２４℃のエステルワックスに変更し、Ｃ．Ｉ．ソルベントブルー７０の添加量を０．７質量部に変えて、実施例１と同様にして行い、平均粒径が６．４μｍのブラック色のトナーを得た。このトナーについて実施例１と同様に評価したところ、概ね良好な結果が得られた。評価結果を表３に示す。
【０１５８】
［実施例５］
実施例１において、ワックスを添加しないことを除いて、実施例１と同様にして行い、平均粒径が６．７μｍのブラック色のトナーを得た。このトナーについて実施例１と同様にして評価したところ、概ね良好な結果が得られた。評価結果を表３に示す。
【０１５９】
［実施例６］
実施例１において、カーボンブラックを平均一次粒径＝２０ｎｍ、ＤＢＰ吸油量＝１３０ｍｌ／１００ｇ、ＢＥＴ比表面積＝８７ｍ^２／ｇ、揮発分＝０．６質量％のカーボンブラックに変更することを除いて、実施例１と同様にして行い、平均粒径が６．８μｍのブラック色のトナーを得た。このトナーについて実施例１と同様にして評価を行ったところ、概ね良好な結果が得られた。評価結果を表３に示す。
【０１６０】
［実施例７］
実施例１において、カーボンブラックを平均一次粒径＝１３２ｎｍ、ＤＢＰ吸油量＝１５４ｍｌ／１００ｇ、ＢＥＴ比表面積＝４１ｍ^２／ｇ、揮発分＝０．６質量％のカーボンブラックに変更することを除いて、実施例１と同様にして行い、平均粒径が６．７μｍのブラック色のトナーを得た。このトナーについて実施例１と同様にして評価を行ったところ、概ね良好な結果が得られた。評価結果を表３に示す。
【０１６１】
［実施例８］
実施例１において、Ｃ．Ｉ．ソルベントブルー７０の添加量を１質量部に変更することを除いて、実施例１と同様にして行い、平均粒径が６．５μｍのブラック色のトナーを得た。このトナーについて実施例１と同様にして評価を行ったところ、５千枚終了時から転写性が悪化した。しかし問題ないレベルであった。評価結果を表３に示す。
【０１６２】
［実施例９］
実施例１において、着色剤としてカーボンブラックの代わりに遊離Ｃｕ含有率が５６０ｐｐｍのＣｕフタロシアニン顔料を８質量部、添加することを除いて、実施例１と同様にして行い、平均粒径が６．７μｍのシアン色のトナーを得た。このトナーについて実施例１と同様にして評価を行ったところ、何れにおいても良好な結果が得られた。評価結果を表３に示す。
【０１６３】
［実施例１０］
実施例１において、着色剤としてカーボンブラックの代わりに遊離Ｃｕ含有率が２６００ｐｐｍのＣｕフタロシアニン顔料を８質量部、添加することを除いて、実施例１と同様にして行い、平均粒径が６．５μｍのシアン色のトナーを得た。このトナーについて実施例１と同様にして評価を行ったところ、着色剤の分散性が悪化しトナー消費量が増大した。しかし問題ないレベルであった。評価結果を表３に示す。
【０１６４】
［実施例１１］
実施例１において、着色剤としてカーボンブラックの代わりに遊離Ｃｕ含有率が８ｐｐｍのＣｕフタロシアニン顔料を８質量部、添加することを除いて、実施例１と同様にして行い、平均粒径が６．６μｍのシアン色のトナーを得た。このトナーについて実施例１と同様にして評価を行ったところ、着色剤の分散性は良好であったもののトナー消費量が増大した。これはＣｕフタロシアニン顔料に十分な発色性がなかったためであると考えられる。しかし問題ないレベルであった。評価結果を表３に示す。
【０１６５】
［比較例１］
以下のトナーを用いること以外は実施例１と同様にして評価を実施した。
・ポリエステル樹脂 １００質量部
（ポリオキシプロピレン（２、２）−２、２−ビス（４−ヒドロキシフェニル）
プロパンとフマル酸の縮重合体）
・カーボンブラック １０質量部
（平均一次粒径＝４０ｎｍ、ＤＢＰ吸油量＝８０ｍｌ／１００ｇ、ＢＥＴ比表面積＝５５ｍ^２／ｇ、揮発分＝０．７質量％）
・Ｃ．Ｉ．ソルベントブルー７０ ２質量部
よりなる材料を熱混練し、冷却後粉砕し、球形化処理を行った後、分級して７．０μｍのブラック色のトナー粒子を得た。
【０１６６】
上記重合体粒子１００質量部と疎水性オイル処理シリカ微粉体（ＢＥＴ比表面積＝２００ｍ^２／ｇ）０．７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、トナーを得た。
【０１６７】
このトナーについて評価を行った結果、特に１万枚プリントアウトした後のカブリ、飛び散り及び転写性が著しく悪化した。これはバインダーとしてポリエステル樹脂を用いたためであると考えられる。評価結果を表３に示す。
【０１６８】
［比較例２］
実施例１において、トナー粒子に疎水性オイル処理シリカ微粉体を混合する前に球形化処理を行うことを除いて、実施例１と同様にして行い、平均粒径が６．８μｍのブラック色のトナーを得た。このトナーについて実施例１と同様にして評価を行ったところ、５千枚終了時にカブリが著しく悪化したので評価を中止した。評価結果を表３に示す。
【０１６９】
［比較例３］
実施例１において、水系媒体中のｐＨを１０．５に変更することを除いて、実施例１と同様にして行い、平均粒径が６．７μｍのブラック色のトナーを得た。このトナーはトナー中の円形度０．９５０未満のトナーの存在割合が３８％に増加した。また、このトナーについて実施例１と同様にして評価を行ったところ、５千枚終了時にカブリが著しく悪化したので評価を中止した。評価結果を表３に示す。
【０１７０】
［比較例４］
実施例１において、水系媒体中のｐＨを４．１に変更することを除いて、実施例１と同様にして行い、平均粒径が６．９μｍのブラック色のトナーを得た。このトナーは円形度標準偏差の値が０．０４６に増加した。また、このトナーについて実施例１と同様にして評価を行ったところ、初期からカブリが著しく悪化したので評価を中止した。評価結果を表３に示す。
【０１７１】
［比較例５］
以下のトナーを用いること以外は実施例１と同様にして評価を実施した。
・スチレン−ブチルアクリレート共重合体 １００質量部
（共重合比＝スチレン：ｎ−ブリルアクリレート＝７：３、Ｍｎ＝５０，０００）
・Ｃ．Ｉ．ソルベントブルー７０ ２質量部
・カーボンブラック １０質量部
（平均一次粒径＝４０ｎｍ、ＤＢＰ吸油量＝８０ｍｌ／１００ｇ、ＢＥＴ比表面積＝５５ｍ^２／ｇ、揮発分＝０．７質量％）
よりなる材料を熱混練し、冷却後粉砕し、分級して７．０μｍのブラック色のトナー粒子を得た。
【０１７２】
上記重合体粒子１００質量部と疎水性オイル処理シリカ微粉体（ＢＥＴ比表面積＝２００ｍ^２／ｇ）０．７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、トナーを得た。
【０１７３】
このトナーについて実施例１と同様にして評価を行った結果、初期からカブリ、飛び散り及び転写性が著しく悪化したので評価を中止した。評価結果を表３に示す。
【０１７４】
［比較例６］
以下のトナーを用いること以外は実施例１と同様にして評価を実施した。
・ポリエステル ９５質量部
（ポリオキシプロピレン（２、２）−２、２−ビス（４−ヒドロキシフェニル）プロパンのジオールとフマル酸、トリメリット酸の縮重合体）
・スチレンとｎ−ブチルメタクリレートの共重合体 ５質量部
（共重合比＝スチレン：ｎ−ブリルアクリレート＝７：３）
・Ｃｕフタロシアニン ２．５質量部
（遊離Ｃｕ含有率＝５６０ｐｐｍ）
・Ｃ．Ｉ．ソルベントブルー７０ ２質量部
よりなる材料を熱混練し、冷却後粉砕し、分級して６．９μｍのシアン色のトナー粒子を得た。
【０１７５】
上記重合体粒子１００質量部と疎水性オイル処理シリカ微粉体（ＢＥＴ比表面積＝２００ｍ^２／ｇ）０．７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、トナーを得た。
【０１７６】
このトナーについて実施例１と同様にして評価を行った結果、初期からカブリ、飛び散り及び転写性が著しく悪化したので評価を中止した。評価結果を表３に示す。
【０１７７】
〔比較例７〕
実施例１において、Ｃ．Ｉ．ソルベントブルー７０の添加量を０．０００５質量部に変更することを除いて、実施例１と同様にして行い、平均粒径が６．８μｍノブラックトナーを得た。このトナーについて、実施例１と同様の評価を行ったところ、着色剤の分散性が著しく悪化したため、プリントアウト画像評価を行わなかった。評価結果を表３に示す。
【０１７８】
【表２】

【０１７９】
【表３】

【０１８０】
【発明の効果】
以上説明したように、本発明によれば、着色力が高く、トナー消費量が少なく、帯電性が良好でカブリ、飛び散り、転写性が良好なトナーが提供される。
【図面の簡単な説明】
【図１】本発明の実施例で用いた画像形成装置の概略図である。
【符号の説明】
１ 感光体
２ トナー担持体
３ 転写材
４ 現像剤
５ 帯電ローラー
６ ブレード[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a toner used for a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet method, and the like, and a method for producing the toner. More specifically, the present invention relates to a toner used in an image forming apparatus that can be used in a copying machine, a printer, a facsimile, a plotter, and the like, and a method of manufacturing the toner.
[0002]
[Prior art]
Conventionally, a developer using an electrophotographic process is prepared by adding a colorant, a charge control agent, and a release agent to a binder resin such as a polyester resin, a styrene-acrylic resin, or an epoxy resin, melt-kneading them, and then dispersing them uniformly. In general, a production method by a pulverization method of pulverizing to a predetermined particle size and further removing excess fine powder and coarse powder using a classifier is used.
[0003]
In recent years, along with the demand for higher image quality and higher resolution of electrophotographic images, toner production methods using a polymerization method have attracted attention, as a demand for smaller toner particle sizes and higher functions has been increasing. In the suspension polymerization method, a coloring agent in a polymerizable monomer which is a raw material of a binder resin, and further, if necessary, a polymerization initiator, a dispersant, a cross-linking agent, a charge control agent, a release agent, a polar resin, A polymerizable monomer composition is prepared by dissolving or dispersing other additives, and the obtained polymerizable monomer composition is added to an aqueous dispersion medium containing a dispersion stabilizer prepared in advance. By using a stirrer, the fine particles are granulated, and then the polymerizable monomer in the granulated particles is polymerized to solidify the particles, and the particles are filtered, washed and dried to obtain a desired particle size. A toner particle having a composition is obtained.
[0004]
The toner using the above polymerization method is a toner having a small particle diameter capable of obtaining an image with excellent image quality, and has a sharp particle size distribution, so that matching with an image forming apparatus is excellent.
[0005]
However, when carbon black was used as a colorant when preparing toner particles, many problems occurred.
[0006]
When carbon black is dispersed in a polymerizable monomer or binder resin, carbon black has a small primary particle size, a large specific surface area, and a structural structure compared to other pigments. In the case where toner particles are hardly dispersed in toner particles and are ubiquitous in toner particles, or in severe cases, particles not containing carbon black are likely to be generated. For this reason, the coloring power of the toner tends to decrease, and the toner consumption tends to increase.
[0007]
Further, in the present color toner, a Cu phthalocyanine pigment is suitably used as a pigment for a cyan toner. Cu phthalocyanine pigments have extremely excellent performance in terms of cost, light resistance, dispersibility and the like.
[0008]
However, recently, further cost reduction of the toner is required, and it is necessary to reduce the addition amount of the Cu phthalocyanine pigment while maintaining the coloring power of the colorant of the toner. In this sense, it is necessary to further improve the dispersibility of the Cu phthalocyanine pigment and enhance the coloring power.
[0009]
Many dispersants have been disclosed to overcome such problems. For example, Patent Document 1 proposes a method for improving dispersibility by using a specific dispersant, but it cannot be said that the method has been sufficiently solved.
[0010]
Further, Patent Documents 2 and 3 propose a method for improving the dispersibility of carbon black by adding a specific azo-based iron complex compound. Certainly, although the dispersibility of carbon black can be sufficiently improved by this method, the degree of polymerization does not increase because the azo-based iron complex compound has the effect of suppressing polymerization, and when the toner is left in an environment of about 45 ° C. , Blocking and other problems may occur.
[0011]
By the way, in the current electrophotographic technology, it is required to output a high-quality image with better fog, scattering, transferability and the like. To provide a higher quality image, the chargeability of the toner is a very important factor.
[0012]
Generally, the toner must be configured to have a positive or negative charge depending on the charge polarity of the electrostatic image to be developed. In order to cause the toner to retain an electric charge, the frictional charging property of the binder resin, which is a main component of the toner, can be used. However, this alone reduces the toner charging property. Therefore, in order to impart a desired frictional charging property to the toner, a charge control agent is added to the toner. A toner containing such a charge controlling agent can obtain a relatively high triboelectric charge, but generally shows a decrease in triboelectric charge under high humidity, and on the other hand, a low charge rate of the toner under low humidity. There is a decrease.
[0013]
One of the causes is considered to be moisture adsorption in the toner and in the vicinity of the charge control agent contained on the toner surface. That is, under high humidity, the amount of water adsorbed on the charge control agent increases, so that the triboelectric charge decreases. Under low humidity, the amount of water adsorbed in the charge control agent decreases, so that the resistance increases and the charging speed decreases. It is considered.
[0014]
Today, the charge control agents known in the art include, as negatively chargeable ones, metal complex salts of monoazo dyes, Cu phthalocyanine pigments, Cu phthalocyanine dyes, and the like.
[0015]
Many of the above-mentioned charge control agents have sufficiently high charge-imparting ability, but have poor charge controllability, so that there are restrictions on binder resins and other materials that can be used in combination.
[0016]
Patent Documents 4, 5, and 6 disclose toners using salicylic acid or a derivative thereof as a charge control agent. However, salicylic acid has substantivity in addition to the fact that the charge control ability fluctuates greatly with respect to temperature and humidity, so that the storage condition of the toner is significantly restricted. Further, since the salicylic acid derivative has a good dispersibility in the binder resin, the matching with the image forming apparatus is improved to some extent, but the addition amount has to be increased in order to exhibit the desired charge control ability.
[0017]
Patent Document 7 discloses that the binder resin is a polyester having a softening point of 50 to 150 ° C. for the purpose of improving the chargeability of the toner. I. A toner containing Solvent Blue 70 is disclosed. However, when a highly polar resin such as polyester is used as the binder resin, C.I. I. Affinity with a Cu phthalocyanine derivative having a polar group such as Solvent Blue 70 works too much, and the effect of the Cu phthalocyanine derivative as a dispersant is lost.
[0018]
In Patent Documents 8, 9, and 10, a styrene polymer or a styrene-acryl copolymer is used as a binder resin. I. A toner containing Solvent Blue 70 is disclosed. Certainly, although the chargeability of the toner is improved to some extent and the dispersibility of the colorant is also improved, the shape of the toner is not precisely controlled, and the development characteristics such as fog are at a sufficient level. It is hard to say that.
[0019]
Patent Documents 11 and 12 disclose toners obtained by depositing a charge control agent on the toner surface in order to obtain a uniform charge-providing ability. Although this method surely stabilizes the chargeability of the toner, the charge control agent is detached from the toner surface after the durability of a large number of sheets, and the effect is reduced, thereby causing a problem in the durability of the toner.
[0020]
Further, in Patent Document 13, after the spherical particles are produced, the spherical particles are immersed in an organic solvent in which the charge control agent pigment is dissolved or dispersed, and then the unnecessary portion is washed off, and the dye concentration on the particle surface is adjusted to a predetermined value. A range adjusted toner is disclosed. However, the dispersion state of the charge control agent pigment on the toner surface obtained by this method is not uniform, which causes a problem in matching with the image forming apparatus. Further, since a dye is used, it is difficult to use the color toner.
[0021]
Further, when the toner is manufactured by the suspension polymerization method as described above, the contact area between the granulated particles and the aqueous dispersion medium is large, so that the structure of the toner having a large number of polar groups such as a charge control agent from the granulated particles. The material tends to easily elute into the aqueous dispersion medium, and the amount of the material having a polar group present on the toner surface and in the vicinity of the surface becomes non-uniform, so that a toner having charging characteristics with excellent environmental stability is obtained. It was hard to be.
[0022]
According to the study of the present inventors, by using a styrene polymer or a styrene-based copolymer as a binder resin and adding a Cu phthalocyanine dye to the toner, the dispersibility of the colorant is dramatically improved, It was found that by precisely controlling the shape of the toner, the chargeability of the toner was improved. However, when a toner containing a Cu phthalocyanine dye is produced by the suspension polymerization method as described above, the Cu phthalocyanine dye is significantly eluted into an aqueous dispersion medium, which affects the granulation of the toner, and consequently the desired It becomes impossible to obtain a toner having a shape.
[0023]
[Patent Document 1]
JP-A-1-145664
[Patent Document 2]
JP-A-10-186713
[Patent Document 3]
JP-A-11-352723
[Patent Document 4]
JP-A-2-190869
[Patent Document 5]
JP-A-2-230163
[Patent Document 6]
JP-A-4-34763
[Patent Document 7]
Japanese Patent Publication No. 5-64339
[Patent Document 8]
JP-A-6-40226
[Patent Document 9]
JP-A-7-11720
[Patent Document 10]
JP-A-9-269615
[Patent Document 11]
JP-A-61-238846
[Patent Document 12]
JP-A-5-134457
[Patent Document 13]
JP-A-3-84558
[0024]
[Problems to be solved by the invention]
An object of the present invention is to provide a toner which has solved the above-mentioned problems and a method for producing the toner.
[0025]
Another object of the present invention is to provide a toner having a high coloring power and requiring a small amount of toner for image reproduction, and a method for producing the toner.
[0026]
It is a further object of the present invention to provide a toner having good toner chargeability and good fog, scattering, and transferability, and a method for producing the toner.
[0027]
[Means for Solving the Problems]
The present invention is a toner containing at least a binder resin, a colorant, and a Cu phthalocyanine derivative,
The binder resin is at least a styrene polymer or a styrene-based copolymer,
A solubility of the Cu phthalocyanine derivative in styrene at 25 ° C. of 5% by mass or more,
The content of the Cu phthalocyanine derivative is 0.1 to 18% with respect to the content of the coloring agent,
In the toner, the proportion of toner particles having a circularity of less than 0.950 measured by a flow type particle image measuring device is 1 to 30%, and the circularity standard deviation is 0.010 to 0.040. And a toner characterized by the following.
[0028]
Further, the present invention provides a method for dispersing at least a polymerizable monomer composition containing a polymerizable vinyl-based monomer, a colorant, a polymerization initiator, and a Cu phthalocyanine derivative in an aqueous dispersion medium. Granulation step of producing particles of the monomer composition,
A polymerization step of polymerizing the polymerizable vinyl monomer in the particles of the polymerizable monomer composition to form toner particles,
The polymerizable vinyl monomer contains at least styrene,
A solubility of the Cu phthalocyanine derivative in styrene at 25 ° C. of 5% by mass or more,
The present invention relates to a method for producing a toner, wherein the polymerization reaction of the polymerizable vinyl monomer from the granulation step to the polymerization step is carried out while maintaining at least the pH of the aqueous dispersion medium at 4.5 to 9.0. .
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
[toner]
The toner of the present invention is a toner containing a specific binder resin and a Cu phthalocyanine derivative having a solubility in styrene at 25 ° C. of 5% by mass or more, and has a circularity of 0. 0 measured by a flow type particle image measuring device. When the proportion of toner having a particle size of less than 950 is 1 to 30% and the standard deviation of circularity satisfies 0.010 to 0.040, the dispersion state of the colorant in the toner and the chargeability are synergistically improved. Can be done.
[0030]
It is essential for the toner of the present invention to add a Cu phthalocyanine derivative. The toner of the present invention improves the dispersibility of the colorant by coexisting with a specific binder resin described later and a Cu phthalocyanine derivative, and further improves the chargeability of the toner by precisely controlling the shape of the toner. It can be something. That is, the coloring power of the toner can be increased, the consumption of the toner can be reduced, and fog, scattering, and transferability can be improved.
[0031]
The Cu phthalocyanine derivative must have a solubility in styrene at 25 ° C. of 5% by mass or more. In order for the Cu phthalocyanine derivative to work effectively in the binder resin, the derivative must be dissolved in the binder resin at the molecular level. When the solubility is less than 5% by mass, the effect as a dispersing agent is lost, and if added until the effect is obtained, fog is deteriorated. The solubility of the Cu phthalocyanine derivative in styrene can be confirmed by UV measurement.
[0032]
The Cu phthalocyanine derivative used in the toner of the present invention is a compound in which various substituents are introduced into the phthalocyanine ring of Cu phthalocyanine, and the solubility in styrene at 25 ° C. is 5% by mass or more. As such a Cu phthalocyanine derivative, from the viewpoints of the dispersibility of the colorant and the chargeability of the toner, the Cu phthalocyanine derivative may be C.I. I. Solvent Blue 4, 14, 22, 25, 35, 40, 49, 55, 63, 70, 73, 78, 83, 84, 85, 86, 91, 94, 95, 104, 194, 195 Preferably, these may be used alone or in combination of two or more.
[0033]
The content of the Cu phthalocyanine derivative is 0.1 to 18% based on the content of the coloring agent. When the content of the Cu phthalocyanine derivative is less than 0.1% with respect to the content of the colorant, the effect of the colorant as a dispersant is not exhibited. There is a tendency for transferability to deteriorate.
[0034]
The effect of the colorant as a dispersant is sufficient even with the Cu phthalocyanine derivative alone, but if necessary, a conventionally known colorant dispersant may be used in combination.
[0035]
It is essential that the binder resin used in the present invention comprises at least a styrene polymer or a styrene copolymer. Styrene polymers or styrene-based copolymers, unlike polyester resins, are relatively low in polarity, have low affinity with Cu phthalocyanine derivatives, and Cu phthalocyanine derivatives do not interact with the binder resin. The effects of both the chargeability of the toner and the dispersibility of the colorant can be maximized.
[0036]
In the present invention, comonomers for the styrene monomer of the styrene copolymer include acrylic acid; styrene derivatives such as butyl acrylate, ethyl acrylate, methyl acrylate, and vinyl toluene; maleic acid; butyl maleate, methyl maleate; Dicarboxylic acid esters having a double bond such as dimethyl maleate; methacrylonitrile, butadiene; vinyl chloride; vinyl esters such as vinyl acetate and vinyl benzoate; ethylene olefins such as ethylene, propylene and butylene; vinyl methyl ketone, vinyl Vinyl ketones such as hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. These vinyl monomers are used alone or in combination of two or more.
[0037]
When using these comonomers, it is preferable to use 40% by mass or less as a monomer component in the copolymer.
[0038]
When the toner of the present invention is produced by a suspension polymerization method, a crosslinking agent may be added in order to give the toner an appropriate hardness.
[0039]
As the crosslinking agent used in the present invention, a polyfunctional polymerizable vinyl monomer is preferable, and specifically, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2′-bis [4- (acryloxydiethoxy) phenyl] propane, trimethylolpropane triacrylate, Tetramethylol methane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tet Ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis [4- (methacryloxy [Diethoxy) phenyl] propane, 2,2'-bis [4- (methacryloxypolyethoxy) phenyl] propane, trimethylolpropane trimethacrylate, tetramethylolmethanetetramethacrylate, divinylbenzene, divinylnaphthalene, divinylether and the like.
[0040]
When the toner of the present invention is produced by a pulverization method, another resin may be used in combination with the styrene polymer or the styrene copolymer.
[0041]
Examples of the types of binder resins that can be used in combination in the present invention include polyester resins, polyol resins, polyvinyl chloride resins, phenolic resins, naturally modified phenolic resins, natural resin modified maleic resins, acrylic resins, methacrylic resins, polyvinyl acetates, and silicones. Resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone indene resins, and petroleum resins. In the present invention, these resins can be used in a range of 40% by mass or less in the binder resin.
[0042]
In the toner of the present invention, it is essential that the proportion of the toner having a circularity of less than 0.950 is 1% to 30%, whereby the toner has good chargeability. When the ratio of the toner having a circularity of less than 0.950 is less than 1%, the chargeability of the toner is too high, the charge-up is easily performed, and the fog tends to be deteriorated. Fog tends to worsen because it is too low. Although the reason for this is not necessarily clear, since the Cu phthalocyanine derivative has a relatively strong hygroscopic property, irregular shaped toner particles having a circularity of less than 0.950, which has irregularities on the toner surface, have a large surface area of the toner. Easy to receive. Therefore, toner particles having a circularity of less than 0.950 have low toner chargeability. However, when toner particles having a circularity of less than 0.950 are appropriately present, it is considered that charge-up is effectively suppressed.
[0043]
Further, it is essential that the toner of the present invention has a circularity standard deviation of 0.010 to 0.040. If the circularity standard deviation is less than 0.010, the toner containing the Cu phthalocyanine derivative has too high a chargeability as described above, and fog is deteriorated. On the other hand, if it exceeds 0.040, the toner containing the Cu phthalocyanine derivative has a broad charge distribution, so that scattering in development deteriorates.
[0044]
As described above, the control of the abundance ratio of the toner having a circularity of less than 0.950 and the circularity standard deviation in the toner is performed when the polymerization is performed by a suspension polymerization method described below during the polymerization reaction from the granulation step to the polymerization step. This is possible depending on the pH of the aqueous dispersion medium.
[0045]
The circularity in the present invention is used as a simple method for quantitatively expressing the shape of a particle. In the present invention, the particle shape is measured using a flow-type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd. And the circularity is determined by the following equation. Further, as shown by the following formula, a value obtained by dividing the total sum of the measured circularities of all the particles by the total number of particles is defined as an average circularity.
[0046]
(Equation 1)

[0047]
The circularity standard deviation SDc is obtained by calculating the average circularity determined by the above equations (1) and (2) as c_av, The circularity of each particle is c_iWhen the number of particles to be measured is m, it is calculated from the following equation (3).
[0048]
(Equation 2)

[0049]
Here, “the same projected area as the particle image” is the area of the binarized toner particle image, and “the perimeter of the projected image of the particle” is the contour obtained by connecting the edge points of the toner particle image. Defined as the length of the line.
[0050]
The “FPIA-1000” used as a measuring device in the present invention calculates the circularity of each particle, calculates the average circularity and the standard deviation of the circularity, and calculates the circularity of the particle. .400 to 1.000 at a 0.010 interval of 0.400 or more and less than 0.410, 0.410 or more and less than 0.420 ... 0.990 or more and less than 1.000, and a division range of 61 such as 1.000 And the calculation method of calculating the average circularity and the circularity standard deviation using the center value and the frequency of the division points is used.
[0051]
Error between each value of the average circularity and the standard deviation of the circularity calculated by this calculation method, and each value of the average circularity and the standard deviation of the circularity calculated by the above-described calculation formula directly using the circularity of each particle. Is very small and practically negligible. In the present invention, the circular shape of each particle described above is used for data handling reasons such as shortening of calculation time and simplification of calculation formula. Utilizing the concept of a calculation formula that directly uses degrees, such a calculation method partially modified is used.
[0052]
The circularity in the present invention is an index indicating the degree of unevenness of the particles, and is 1.000 when the particles are perfectly spherical, and the circularity becomes smaller as the surface shape becomes more complicated.
[0053]
The equivalent circle diameter is the equivalent circle diameter = (projected area of particle / π).^1/2X2, and the circle-equivalent number average diameter (D1) represents the average value of the circle-equivalent diameter of the toner based on the number, and the particle diameter (center value) at the dividing point i of the particle size distribution. d_i, Frequency f_iThen, it is expressed as the following equation.
[0054]
(Equation 3)

[0055]
The dividing point of the particle size distribution in the present invention is as shown in the following table.
[0056]
[Table 1]

[0057]
As a specific measuring method, 10 ml of ion-exchanged water from which impurity solids and the like have been removed in advance in a container is prepared, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, and then further measured. Add 0.02 g of sample and disperse uniformly. As a means for dispersing, a dispersion liquid of 5 mm in diameter was used as a vibrator with a titanium alloy chip mounted on an ultrasonic dispersing machine “UH-50” (manufactured by SMT Corporation). And At this time, the dispersion is appropriately cooled so that the temperature of the dispersion does not exceed 40 ° C.
[0058]
The shape of the toner is measured using the above-mentioned flow type particle image measuring apparatus, and the concentration of the dispersion liquid is readjusted so that the concentration of the toner particles at the time of measurement becomes 3000 to 10,000 particles / μl. measure. After the measurement, the existence ratio of toner particles having a circularity of less than 0.950 and the circularity standard deviation are obtained using this data.
[0059]
The present invention can be preferably applied to a black toner and a cyan toner in consideration of the hue and the like of the Cu phthalocyanine derivative used. Among these, the present invention can be particularly preferably applied to a black toner using carbon black as a colorant or a cyan toner using Cu phthalocyanine pigment as a colorant.
[0060]
First, carbon black will be described.
[0061]
As the carbon black used in the present invention, those having an average primary particle size of 25 to 120 nm are preferable. Even if the carbon black having an average primary particle size of less than 25 nm is used in combination with the Cu phthalocyanine derivative according to the present invention, the aggregation of the carbon black becomes too strong, and it is difficult to uniformly disperse the carbon black in the toner. Further, carbon black having an average primary particle size of more than 120 nm cannot obtain a sufficient coloring power even when dispersed well, and if the carbon black is used until a sufficient coloring power is obtained, the chargeability of the toner decreases. Causes fog.
[0062]
The method for measuring the average primary particle size of carbon black used in the present invention is determined by taking an enlarged photograph of a cross section at a magnification of 30,000 times with a transmission microscope and calculating the average value of 100 particles of carbon black.
[0063]
Further, the DBP oil absorption of the carbon black used in the present invention is preferably 20 to 180 ml / 100 g, and more preferably 30 to 160 ml / 100 g.
[0064]
The carbon black preferably used in the present invention has a smaller specific surface area and a smaller volatile content than those used for ordinary toners. Carbon black having a small specific surface area and a small amount of volatile components has a small amount of polymerization-inhibiting functional groups. Therefore, when a toner is produced by suspension polymerization, there is an advantage that polymerization inhibition is low.
[0065]
Therefore, the carbon black used in the present invention has a specific surface area of 100 m²/ G or less, preferably 30 to 90 m²/ G, more preferably 40 to 90 m²/ G, and the volatile content is 2% by mass or less, preferably 0.1 to 1.8% by mass, more preferably 0.1 to 1.7% by mass.
[0066]
The measurement of the DBP oil absorption, specific surface area, and volatile content of the carbon black used in the present invention is described below.
[0067]
(1) The DBP oil absorption of carbon black is measured according to “JIS 4656/1”.
[0068]
(2) The specific surface area of the carbon black is measured by nitrogen adsorption according to “JIS 4652”.
[0069]
(3) Volatile content of carbon black is measured according to “JIS 1126”.
[0070]
In the toner of the present invention, a magnetic powder may be used alone or in combination with carbon black as a colorant. Specifically, iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel, or aluminum and cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, and cadmium. , Calcium, manganese, selenium, titanium, tungsten, and alloys of metals such as vanadium and ferromagnetic substances such as mixtures thereof.
[0071]
These magnetic powders preferably have a number average particle diameter of 0.05 to 2 μm, preferably 0.1 to 0.5 μm, and the content in the toner particles is 100 parts by mass of the resin component containing the binder resin. About 20 to 200 parts by weight, particularly preferably 40 to 150 parts by weight, is suitable.
[0072]
The magnetic powder preferably has a magnetic property of 20 to 150 eersted (Oe), a saturation magnetization of 50 to 200 emu / g, and a residual magnetization of 2 to 20 emu / g when 10 KOe is applied.
[0073]
Next, the Cu phthalocyanine pigment will be described.
[0074]
The Cu phthalocyanine pigment used in the present invention preferably has a free Cu content of 10 to 2000 ppm. Although the details are unknown, by specifying free Cu present in the Cu phthalocyanine pigment, the dispersibility of the colorant can be further enhanced by the interaction with the Cu phthalocyanine derivative.
[0075]
When the content of free Cu is less than 10 ppm, the Cu phthalocyanine pigment becomes a coloring agent that does not sufficiently form a color, so that the coloring power is inferior. When the content of free Cu exceeds 2000 ppm, the dispersibility of the Cu phthalocyanine pigment tends to deteriorate due to free Cu.
[0076]
Cu phthalocyanine pigment, usually, phthalic acid or a phthalic acid derivative, urea or a urea derivative and a Cu compound are heated in an inert organic solvent in the presence of a phthalocyanine catalyst such as a molybdenum compound to obtain a crude Cu phthalocyanine. It is manufactured through a pigmentation process for making this finer. The Cu phthalocyanine pigment having a content of free Cu of 10 to 2000 ppm used in the present invention is, in the method for producing Cu phthalocyanine, after completion of the heating reaction, the solvent is distilled off from the reaction product under reduced pressure, and the obtained residue is removed. After sufficient washing with water or after obtaining crude Cu phthalocyanine, it can be obtained by sufficiently washing with water or an acid in a pigmentation step for refining the crude Cu phthalocyanine. Is preferred. For example, in the method for producing Cu phthalocyanine, after completion of the heating reaction, the solvent is distilled off from the reaction product under reduced pressure, and the obtained residue is washed with water to reduce the content of free Cu to about 12000 ppm. The content of free Cu in the pigment finally obtained by passing through a water washing step of pigmentation by a solvent salt milling method or an acid pasting method and a pickling step of pigmentation by a dry milling method is 10 to 2000 ppm. Can be. Further, in order to further reduce the content of free Cu, the residue is subjected to acid washing using diluted sulfuric acid or the like. In addition to a molybdenum compound catalyst which is usually used, a trace amount of a ruthenium compound and / or an osmium compound is reduced. You may use the method of adding to a reaction system.
[0077]
The free Cu content is determined as follows. After precisely weighing 3.0 g of a Cu phthalocyanine sample, 30.0 g of sulfuric acid is added and dissolved, then added to 150 ml of cold water, and the mixture is stirred at 90 ° C. for 30 minutes. Next, the precipitate is filtered, and the obtained wet cake is washed with hot water until the washing liquid becomes neutral. Free Cu in the filtrate and the washing solution is determined by an atomic absorption method.
[0078]
Other colorants for chromatic toners can be used for yellow and magenta toner colorants.
[0079]
As the yellow colorant used in the present invention, compounds represented by a condensed azo compound, an isoindolinone compound, an anthraquinone compound, an azo metal complex, a methine compound and an allylamide compound are used. Specifically, for example, C.I. I. Pigment Yellow 12 to 15, 17, 62, 74, 83, 93 to 95, 97, 109, 110, 111, 120, 127 to 129, 147, 155, 168, 174, 176, 180, 181, 191 are preferred. Used.
[0080]
As the magenta colorant used in the present invention, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, for example, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 144, 146, 166, 169, 177, 184, 185, 202, It is particularly preferred to use 206, 220, 221, 254.
[0081]
These colorants can be used alone or as a mixture, and can also be used in a solid solution state.
[0082]
It is also a preferable embodiment to use a wax component in the toner of the present invention.
The wax used in the toner of the present invention preferably has a melting point of 50 to 120 ° C. When the toner is manufactured by suspension polymerization, when the melting point of the wax is in the above range, the toner particles in the granulation step have an appropriate viscosity, and the Cu phthalocyanine derivative exists in a good state in the toner. Therefore, the chargeability of the toner is further improved. When the melting point of the wax is out of the above-mentioned range, or when the wax is not added, the dispersibility of the Cu phthalocyanine derivative is deteriorated, and the fog and scattering tend to be deteriorated.
[0083]
Specific examples of the wax used in the present invention include paraffin wax, microcrystalline wax, petroleum-based wax such as petrolactam and its derivatives, montan wax and its derivatives, Fischer-Tropsch hydrocarbon wax and its derivatives, and polyethylene. Representative examples include polyolefin waxes and their derivatives, natural waxes such as carnauba wax and candelilla wax and their derivatives, and the like. Derivatives also include oxides, block copolymers with vinyl monomers, and graft-modified products. . Also, 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.
[0084]
Among these, when polyolefin, hydrocarbon wax by petroleum wax, petroleum-based wax, higher alcohol, or higher ester is used, the effect of improving developability and transferability is further enhanced. Incidentally, an antioxidant may be added to these wax components as long as the chargeability of the toner is not affected. Further, it is preferable to use 1 to 30 parts by mass of these wax components with respect to 100 parts by mass of the binder resin.
[0085]
The wax component used in the present invention preferably has a number average molecular weight (Mn) of 200 to 2,000 and Mw / Mn of 3.0 or less in a molecular weight distribution measured by gel permeation chromatography (GPC). If the Mn of the wax component is less than 200, the ratio of the low molecular weight component increases, and as a result, problems arise in the chargeability of the toner and the matching with the image forming apparatus, which is not preferable. When Mn exceeds 2,000 or Mw / Mn exceeds 3.0, it becomes difficult to appropriately smooth the fixed image surface, which is not preferable from the viewpoint of lowering the color mixing property. When toner particles are obtained by the above method, granulation and polymerization are carried out in an aqueous dispersion medium, so that a wax component is mainly deposited during granulation, which is not preferable.
[0086]
The molecular weight distribution of the wax component is measured by GPC under the following conditions.
[0087]
<GPC measurement conditions>
Apparatus: GPC-150C (manufactured by Waters)
Column: GMH-HT (manufactured by Tosoh Corporation)
Temperature: 135 ° C
Solvent: o-dichlorobenzene (0.1% ionol added)
Flow rate: 1.0 ml / min
Sample: 0.4 ml of 0.15 mass% sample is injected
The measurement is performed under the above conditions, and the molecular weight of the sample is calculated by using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample and converting the polyethylene into a conversion formula derived from the Mark-Houwink viscosity formula.
[0088]
In the toner of the present invention, the Cu phthalocyanine derivative has an effect as a charge control agent, but if necessary, another charge control agent may be used in combination. Examples of charge control agents that can be used in combination include metal compounds of aromatic carboxylic acids such as salicylic acid, naphthoic acid and dicarboxylic acid as negative charge control agents; high molecular compounds having sulfonic acid or carboxylic acid groups in side chains; boron compounds A urea compound; a silicon compound; Examples of the positive charge control agent include a quaternary ammonium salt; a polymer compound having the quaternary ammonium salt in a side chain; a guanidine compound; and an imidazole compound.
[0089]
As another charge control agent, a resin type is also a preferable embodiment. As the resin type, for example, a polymer having a sulfonic acid group is more preferable. Examples of the polymer having a sulfonic acid group suitably used in the toner of the present invention include a high molecular compound having a sulfonic acid group in a side chain, and the like. In the case where a high-molecular-weight compound containing styrene and / or a styrene (meth) acrylate copolymer by mass is used, preferable charging characteristics can be enjoyed. When the monomer ratio is less than 1% by mass, the colorant in the toner tends to be unevenly distributed toward the inside of the toner, and the surface of the toner tends to be soft. If it exceeds 10% by mass, the colorant tends to be unevenly distributed toward the surface of the toner, and the toner surface tends to be hard.
[0090]
For example, when a toner is manufactured by a suspension polymerization method, a copolymer containing a (meth) acrylamide-based monomer as a polymer having a sulfonic acid group can easily control the amount of a colorant present on the toner surface. Is possible.
[0091]
The sulfonic acid group-containing (meth) acrylamide-based monomer is preferably represented by the following formula (A), and specifically, 2-acrylamido-2-methylpropanoic acid or 2-methacrylamido-2-methyl And propanoic acid.
[0092]
Embedded image

[0093]
(In the above general formula, R₁Represents a hydrogen atom or a methyl group;₂And R₃Is a hydrogen atom, C₁~ C₁₀Represents an alkyl group, an alkenyl group, an aryl group, or an alkoxy group, and n represents an integer of 1 to 10. )
[0094]
The above-mentioned polymer containing a sulfonic acid group forms a salt structure at the sulfonic acid group portion by adding an inorganic compound containing an alkali metal and / or an alkaline earth metal during toner production. In the case of a high molecular compound using a sulfonic acid group-containing (meth) acrylamide-based monomer as described above, the formation of a sulfobetaine structure in the molecule is suppressed, and the interaction with the coloring agent of the present invention while preventing hydration. , The chargeability of the toner with respect to environmental changes is further improved. In particular, when a dispersion stabilizer containing an alkali metal and / or an alkaline earth metal as described below is used when a toner is produced by a suspension polymerization method, a salt structure with a sulfonic acid group can be easily formed. It is preferable because it is possible.
[0095]
Examples of the alkali metal or alkaline earth metal capable of forming a salt structure with the sulfonic acid group as described above include lithium, sodium, potassium, calcium, barium, beryllium, magnesium and the like, with calcium being preferred.
[0096]
When the toner of the present invention is produced by a polymerization method, the above-mentioned resins can be used together, but it is particularly preferable to add a polyester resin (hereinafter, referred to as “polar resin”) from the viewpoint of charging. . By adding a polar resin to the toner, it is possible to prevent the colorant in the toner from being unevenly distributed near the toner surface. Further, the presence of the polar resin can prevent the Cu phthalocyanine derivative from being eluted into the aqueous medium when the toner is polymerized in the aqueous medium. For example, in the case where a toner is directly produced by a suspension polymerization method described below, when a polar resin as described above is added, according to the balance between the polarity of the polymerizable monomer composition to be toner particles and the polarity of the aqueous dispersion medium. It can be controlled so that the added polar resin forms a thin layer on the surface of the toner particles or exists with a gradient from the surface of the toner particles toward the center. At this time, the colorant in the toner is maintained in a good dispersion state and is not unevenly distributed on the toner surface. In particular, when a polar resin having an acid value of 1 to 20 mgKOH / g is used, it is easy to realize the above-described colorant dispersion state.
[0097]
The addition amount of the polar resin is preferably 25 parts by mass or less, more preferably 15 parts by mass or less based on 100 parts by mass of the specific binder resin so that the effect of the Cu phthalocyanine derivative is not lost. is there.
[0098]
Typical polyester resins used as such polar resins include, as alcohol components, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, a bisphenol derivative represented by the following formula (B) and the following formula (C) And polyester resins using the diols shown.
[0099]
Embedded image

[0100]
(In the formula, R represents an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10.)
[0101]
Embedded image

[0102]
A particularly preferred alcohol component of the polyester resin is a bisphenol derivative represented by the above formula (B), and examples of the acid component include phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid and anhydrides thereof.
[0103]
Examples of the acid component include benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or anhydrides thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid or anhydrides thereof; Can be Further, polyvalent carboxylic acids such as trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and anhydrides thereof can also be used.
[0104]
In addition, when a reactive polyester resin or a polycarbonate resin is used as the polar resin, the charging characteristics of the toner are improved, image fogging and scattering are improved, and a high-quality image excellent in dot reproducibility can be obtained. it can. In addition, it is possible to impart appropriate mechanical strength to the toner particles, minimizing the influence of toner deterioration received from the image forming apparatus, and improving durability against multiple printouts and matching with the image forming apparatus. . Further, it is possible to minimize the influence of a toner manufacturing process such as a toner sphering process for achieving the toner shape distribution as described above and a drying process when directly manufacturing a toner by a polymerization method. Further, two or more types of polar resins can be used in combination, and the chargeability of the polar resin itself can be used.
[0105]
If the molecular weight of the polyester resin that can be used in the present invention is too low, the toner surface becomes soft, and thus the blocking resistance may decrease. Conversely, if the molecular weight is too high, for example, in the case of obtaining a toner by a polymerization method, it becomes difficult to dissolve the polyester resin in the polymerizable monomer, so that the production becomes difficult. Therefore, the reactive polyester resin having a weight average molecular weight in the range of 3,000 to 100,000 is suitable for obtaining a toner having particularly excellent performance.
[0106]
The addition of an inorganic fine powder to the toner of the present invention is a preferred embodiment for improving developability, transferability, charging stability, fluidity and durability. Known inorganic fine powders can be used, but are preferably selected from silica, alumina, titania or oxides thereof. Among them, silica is more preferable. As the silica, both a so-called dry method produced by vapor phase oxidation of a silicon halide or an alkoxide or a dry silica called a fumed silica, and an alkoxide, a so-called wet silica produced from water glass or the like can be used. Low silanol groups on the surface and inside the silica fine powder,₂O, SO₃ ^2-Dry silica with a small production residue such as is preferred. In the case of fumed silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the production process. Is also included.
[0107]
The inorganic fine powder used in the present invention has a specific surface area of 30 m by nitrogen adsorption measured by the BET method.²/ G or more, especially 50 to 400 m²/ G gives good results, and is used in an amount of 0.3 to 8 parts by mass, preferably 0.5 to 5 parts by mass, per 100 parts by mass of the toner.
[0108]
By coexisting the inorganic fine powder whose BET specific surface area is controlled as described above with a Cu phthalocyanine derivative existing near the toner surface, the amount of water adsorbed on the toner particles is controlled, and the amount of triboelectric charge and the control of the charge speed are controlled. The effect increases. Further, the colorant exposed on the toner surface can be appropriately covered, and the adverse effect of the colorant on the charging characteristics can be suppressed.
[0109]
Furthermore, since the toner is given an appropriate fluidity, the uniform chargeability of the toner is synergistically improved, and the excellent effect is maintained even when a large number of printouts are continuously performed.
[0110]
The BET specific surface area of the inorganic fine powder is 30 m²If it is less than / g, it is difficult to impart appropriate fluidity to the toner. 400m BET specific surface area²If the ratio exceeds / g, the inorganic fine powder is embedded in the surface of the toner particles during continuous printout, so that the fluidity of the toner may decrease.
[0111]
The specific surface area of the inorganic fine powder is measured by adsorbing nitrogen gas on the sample surface using a specific surface area measuring apparatus “Autosorb 1” (manufactured by Yuasa Ionics) and calculating the specific surface area by the BET multipoint method. .
[0112]
When the amount of the inorganic fine powder is less than 0.3 parts by mass with respect to 100 parts by mass of the toner particles, the effect of adding the inorganic fine powder is not exhibited. In addition to causing a problem in the fixing property, the loose inorganic fine powder significantly deteriorates the matching with the image forming apparatus.
[0113]
In addition, the inorganic fine powder used in the present invention may contain, if necessary, a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, a silane coupling agent, a functional group for the purpose of hydrophobicity, charge control, and the like. It is also possible and preferable to use a treating agent such as a silane coupling agent, an organic silicon compound, an organic titanium compound, or a combination of various treating agents.
[0114]
Furthermore, in order to maintain a high charge amount and achieve a high transfer rate, it is preferable that the inorganic fine powder be treated with at least silicone oil.
[0115]
In the toner of the present invention, other additives such as lubricant powders such as Teflon (registered trademark) powder, zinc stearate powder, polyvinylidene fluoride powder; cerium oxide powder, Abrasives such as silicon powder and strontium titanate powder; fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agents; or conductivity-imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder Further, organic fine particles and inorganic fine particles of opposite polarity can be used in small amounts as a developing property improver.
[0116]
The toner of the present invention can be used as it is as a one-component developer or as a two-component developer by mixing with a carrier.
[0117]
When used as a two-component developer, for example, the magnetic carrier to be mixed with the toner is composed of iron, copper, zinc, nickel, cobalt, manganese, an element selected from chromium alone or in a ferrite state containing a plurality of elements. You. The shape of the magnetic carrier can be any of a spherical shape, a flat shape, and an amorphous shape, and a shape in which the fine structure of the surface state (for example, surface unevenness) is appropriately controlled can also be used. Further, a resin-coated carrier whose surface is coated with a resin or a magnetic material-dispersed resin carrier can also be suitably used. The average particle size of the carrier used is preferably 10 to 100 μm, more preferably 20 to 50 μm. When the carrier and the toner are mixed to prepare a two-component developer, the toner concentration in the developer is preferably about 2 to 15% by mass.
[0118]
[Method of Manufacturing Toner]
The method for producing a toner according to the present invention comprises dispersing at least a polymerizable monomer composition containing a polymerizable vinyl monomer, a colorant, a polymerization initiator, and a Cu phthalocyanine derivative in an aqueous dispersion medium. A granulating step of producing particles of the hydrophilic monomer composition;
A polymerization step of polymerizing the polymerizable vinyl monomer in the particles of the polymerizable monomer composition to form toner particles,
The polymerizable vinyl monomer contains at least styrene,
A solubility of the Cu phthalocyanine derivative in styrene at 25 ° C. of 5% by mass or more,
It is essential that the polymerization reaction of the polymerizable vinyl-based monomer from the granulation step to the polymerization step be performed while maintaining at least the pH of the aqueous dispersion medium at 4.5 to 9.0.
[0119]
In the method for producing a toner according to the present invention, when the pH of the aqueous medium is less than 4.5, a dispersing agent necessary for forming particles in the granulation step does not sufficiently work, and a toner having a desired shape cannot be obtained. . When the pH exceeds 9.0, the Cu phthalocyanine derivative is eluted into the aqueous medium, so that not only a toner having a desired shape cannot be obtained, but also the chargeability of the toner deteriorates.
[0120]
If the polymerization conversion of the polymerizable vinyl monomer becomes 80% or more in the polymerization step, the shape and internal state of the toner are maintained, so that the pH of the aqueous medium is adjusted to less than 4.5 as necessary. Alternatively, it may be readjusted to exceed 9.0.
[0121]
In the present invention, the “polymerization conversion” of the polymerizable vinyl monomer refers to the total mass (W) of the polymerizable vinyl monomer used in the polymerizable monomer composition.₁), The total mass of unreacted polymerizable vinyl monomers (W₂) Is determined from the following equation by quantifying:
[0122]
Polymerization conversion (%) = ｛(W₁-W₂) / W₁｝ × 100
[0123]
Further, the mass of the unreacted polymerizable vinyl monomer was determined by adding a polymerization terminator or cold methanol to the collected sample immediately after sampling from the reaction vessel to stop the polymerization reaction. The method can be quantified by applying a known method such as a method using thermogravimetry (TG), which is measured as a weight loss during heating, and (2) a method using gas chromatography (GC). Among these, the method using GC is a particularly effective method.
[0124]
In the method for producing a toner of the present invention, an aqueous dispersion medium using a known inorganic or organic dispersant can be used as the aqueous medium. 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. Examples of the organic dispersant include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, and starch.
[0125]
In addition, 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, and calcium oleate can be used.
[0126]
In the method for producing a toner of the present invention, an inorganic sparingly water-soluble dispersant is preferable, and a sparingly water-soluble inorganic dispersant which is soluble in an acid is preferably used. In addition, when using a poorly water-soluble inorganic dispersant to prepare an aqueous dispersion medium, these dispersants are 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the polymerizable vinyl monomer. It is preferable to use such a ratio. Further, in the present invention, it is preferable to prepare an aqueous dispersion medium using 200 to 3,000 parts by mass of water with respect to 100 parts by mass of the polymerizable monomer composition.
[0127]
When preparing an aqueous dispersion medium in which a poorly water-soluble inorganic dispersant is dispersed as described above, a commercially available dispersant may be used as it is, but dispersant particles having a fine uniform particle size may be obtained. For this purpose, a poorly water-soluble inorganic dispersant as described above may be formed in a liquid medium such as water under high-speed stirring. For example, when using tricalcium phosphate as a dispersant, a preferable dispersant can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring to form fine particles of tricalcium phosphate. .
[0128]
Specific examples of the polymerization initiator used in the production method of the toner of the present invention include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, Azo or diazo polymerization initiators such as, 1, -azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; A peroxide polymerization initiator such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide is used. The amount of these polymerization initiators varies depending on the desired degree of polymerization, but is generally 0.1 to 20 parts by mass based on 100 parts by mass of the polymerizable vinyl monomer. The type 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.
[0129]
In order to control the degree of polymerization, a known chain transfer agent and polymerization inhibitor may be further added to the polymerizable monomer composition. These additives may be added to the polymerizable monomer composition in advance, or may be added as needed during the polymerization reaction.
[0130]
Hereinafter, embodiments of the present invention will be described.
[0131]
[Embodiment 1]
At least a binder resin, a colorant, and a toner containing a Cu phthalocyanine derivative,
The binder resin is at least a styrene polymer or a styrene-based copolymer,
A solubility of the Cu phthalocyanine derivative in styrene at 25 ° C. of 5% by mass or more,
The content of the Cu phthalocyanine derivative is 0.1 to 18% with respect to the content of the coloring agent,
In the toner, the proportion of toner particles having a circularity of less than 0.950 measured by a flow type particle image measuring device is 1 to 30%, and the circularity standard deviation is 0.010 to 0.040. A toner characterized by the following.
[0132]
[Embodiment 2]
In Embodiment 1, the Cu phthalocyanine derivative is C.I. I. Solvent Blue 4, 14, 22, 25, 35, 40, 49, 55, 63, 70, 73, 78, 83, 84, 85, 86, 91, 94, 95, 104, 194, 195 .
[0133]
[Embodiment 3]
In Embodiment 1 or 2, the colorant is carbon black having an average primary particle size of 25 to 120 nm.
[0134]
[Embodiment 4]
In any one of Embodiments 1 to 3, the colorant is a Cu phthalocyanine pigment having a free Cu content of 10 to 2000 ppm.
[0135]
[Embodiment 5]
In any one of Embodiments 1 to 4, the toner contains at least a wax component having a melting point of 50 to 120 ° C.
[0136]
[Embodiment 6]
At least a polymerizable monomer composition containing a polymerizable vinyl monomer, a colorant, a polymerization initiator, and a Cu phthalocyanine derivative is dispersed in an aqueous dispersion medium, and particles of the polymerizable monomer composition are dispersed. A granulation process to produce
A polymerization step of polymerizing the polymerizable vinyl monomer in the particles of the polymerizable monomer composition to form toner particles,
The polymerizable monomer contains at least styrene,
A solubility of the Cu phthalocyanine derivative in styrene at 25 ° C. of 5% by mass or more,
A method for producing a toner, characterized in that the polymerization reaction of the polymerizable vinyl monomer from the granulation step to the polymerization step is performed while maintaining at least the pH of the aqueous dispersion medium at 4.5 to 9.0.
[0137]
[Embodiment 7]
In Embodiment 6, the Cu phthalocyanine derivative is C.I. I. Solvent Blue 4, 14, 22, 25, 35, 40, 49, 55, 63, 70, 73, 78, 83, 84, 85, 86, 91, 94, 95, 104, 194, 195 .
[0138]
【Example】
Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited thereto.
[0139]
[Example 1]
360 parts by mass of ion-exchanged water and 0.1 mol / l of Na in a four-necked container₃PO₄430 parts by mass of the aqueous solution was added, and the mixture was kept at 60 ° C. while stirring at 10,000 rpm using a high-speed stirrer homomixer. After adding 10 parts by mass of 1 N hydrochloric acid, 1.0 mol / l-CaCl₂34 parts by mass of an aqueous solution is gradually added, and a fine hardly water-soluble dispersion stabilizer Ca is added.₃(PO₄)₂The aqueous dispersion medium containing was prepared. At this time, the pH of the aqueous medium was 5.3.
[0140]
On the other hand, as a dispersoid,
・ Styrene monomer 83 parts by mass
・ 17 parts by mass of n-butyl acrylate
・ 8 parts by mass of carbon black
(Average primary particle size = 40 nm, DBP oil absorption = 80 ml / 100 g, BET specific surface area = 55 m²/ G, volatile content = 0.7% by mass)
・ 5 parts by mass of polyester resin
(Mw = 1200, Mn = 5700, acid value = 10 mgKOH / g)
・ C. I. Solvent Blue 70 0.3 parts by mass
(Solubility in styrene: 26% by mass)
・ Divinylbenzene 0.2 parts by mass
-Copolymerization of styrene and 2-acrylamido-2-methylpropanoic acid (AMPS)
Body 1 part by mass
(Copolymerization ratio = styrene: AMPS = 96: 4)
・ 12 parts by mass of ester wax
(Melting point = 60 ° C., Mn = 350, Mw / Mn = 2.1)
Is dispersed using an attritor (manufactured by Mitsui Kinzoku Co., Ltd.) for 4 hours, and then 3 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) is added, and a polymerizable monomer composition is added. Was prepared.
[0141]
Next, the polymerizable monomer composition is charged into the aqueous dispersion medium, and the mixture is stirred for 4 minutes under an N2 atmosphere at an internal temperature of 60 ° C. while maintaining the rotation speed of the high-speed stirring device at 10,000 rpm. And the polymerizable monomer composition was granulated. Thereafter, the stirring apparatus was replaced with a paddle stirring blade, and the temperature was maintained at the same temperature while stirring at 200 rpm, and polymerization was performed for 5 hours. Thereafter, the temperature was raised to 80 ° C., and the polymerization was further performed for 5 hours. After completion of the polymerization, the mixture was cooled, diluted hydrochloric acid was added to adjust the pH of the aqueous dispersion medium to 1.2, and the poorly water-soluble dispersant was dissolved. Further, after solid-liquid separation by pressure filtration, washing was performed with 2,000 parts by mass of water. Thereafter, drying was performed at 45 ° C. for 4 hours using a vacuum drying apparatus to obtain black toner particles having an average particle size of 6.4 μm.
[0142]
100 parts by mass of the polymer particles and hydrophobic oil-treated silica fine powder (BET specific surface area = 200 m²/ G) 0.7 mass parts was dry-mixed with a Henschel mixer (manufactured by Mitsui Kinzoku Co., Ltd.) to obtain a toner. Table 2 shows the ratio of the toner having a circularity of less than 0.950 and the circularity standard deviation in the obtained toner.
[0143]
Further, when the dispersion state of the colorant was evaluated for this toner, it was very good. Table 3 shows the evaluation results. In addition, the evaluation method was performed as follows. Examples 2 to 9 and Comparative Examples 1 to 5 described later also follow this evaluation method.
[0144]
(Evaluation of dispersion state of colorant)
An enlarged photograph of the cross section of the toner was taken at a magnification of 12,000 times with a transmission microscope (TEM) to observe the dispersion state of the colorant in the toner. The evaluation criteria are as follows.
A: Very good.
B: Dispersion is generally good although slight aggregation is observed.
C: A dispersed colorant and an aggregated colorant are mixed.
D: The coloring agent is completely agglomerated, and there are toner particles containing no coloring agent.
[0145]
Next, 10,000 printout image evaluations were performed. A laser beam printer (manufactured by Canon) as shown in FIG. 1 was prepared as an image forming apparatus. In the figure, 1 is a photosensitive member, 2 is a toner carrier, 3 is a transfer material, 4 is a developer, 5 is a charging roller, and 6 is a blade. This device was modified so that the process speed became 150 mm / s. As shown in FIG. 1, this apparatus uniformly charges the photoconductor 1 using a charging roller 5 to which a DC and an AC component are applied. At this time, the DC component is controlled to a constant voltage, and the AC component is controlled to a constant current. After charging, an image portion is exposed by laser light to form an electrostatic latent image, and a toner image is formed as a visible image by the developer 4, and then the toner image is transferred to the transfer material 3 by a transfer roller to which a voltage is applied. Have the process of transcription.
[0146]
The toner produced as described above was used as the developer 4, and process conditions were set so as to satisfy the following development conditions.
[0147]
Photoconductor dark area potential -700V
Photoconductor light section potential -150V
The developing bias is set so that the initial image density is 1.50 in the range of -100 to -900 V with only the DC component, and then readjusted to be 1.50 every 1000 sheets. Printout evaluation.
[0148]
The printout evaluation was performed under normal temperature and normal humidity on a continuous printout test of 10,000 sheets with an image pattern of 4% area ratio printing on A4 size paper, and the image evaluation at the initial 5,000 sheets and 10,000 sheets was performed. went. As a result, the toner consumption, the image density, the image fog, the scattering, and the transferability were all good, and the same image quality as the initial one was obtained. Table 3 shows the evaluation results.
[0149]
The evaluation method is as follows, and Examples 2 to 9 and Comparative Examples 1 to 5 described later also follow this evaluation method.
[0150]
[Toner consumption]
The amount of toner consumed when printout evaluation of 10,000 sheets is performed from the beginning.
A: Less than 250g
B: 250 g or more and less than 300 g
C: 300 g or more and less than 350 g
D: 350g or more
[0151]
(Image density)
Plain paper for ordinary copiers (75 g / m²), A solid black image having a side of 5 mm in the positive direction is printed out, and the relative density with respect to the printout image of the white background portion where the document density is 0.00 is measured using “Macbeth reflection densitometer RD918” (manufactured by Macbeth). It was measured.
A: 1.40 or more
B: 1.30 or more and less than 1.40
C: 1.00 or more and less than 1.30
D: less than 1.00
[0152]
[Image fog]
The toner between development and transfer on the photoreceptor at the time of forming a solid white image is taped off with a Mylar tape and peeled off, and the reflection density of a piece of paper stuck on paper is measured with a "Macbeth reflection densitometer RD918". The evaluation was performed using a numerical value obtained by subtracting the reflection density when the Mylar tape was stuck on paper as it was from the obtained reflection density. The smaller the numerical value, the more the image fog is suppressed.
A: Less than 0.03
B: 0.03 or more and less than 0.07
C: 0.07 or more and less than 0.15
D: 0.15 or more
[0153]
[Image splatter]
This is a splattering evaluation with fine thin lines related to the image quality of a graphical image.²) Was visually evaluated for the reproducibility of the line image and the scattering of the toner to the peripheral portion when printed out.
A: Almost no occurrence, showing good line reproducibility.
B: Slight scattering is observed.
C: Slight scattering is observed, but there is little influence on line reproducibility.
D: A noticeable hollow is observed.
[0154]
(Transferability)
The transfer residual toner on the photoreceptor at the time of forming a solid black image is taped off with a Mylar tape and peeled off, and the reflection density of the tape pasted on paper is measured with a “Magbeth reflection densitometer RD918”. The evaluation was performed using a numerical value obtained by subtracting the reflection density when the Mylar tape was stuck on paper as it was from the obtained reflection density. The smaller the value, the better the transferability.
A: Less than 0.03
B: 0.03 or more and less than 0.07
C: 0.07 or more and less than 0.10
D: 0.10 or more
[0155]
[Example 2]
In Example 1, 83 parts by mass of styrene and 17 parts by mass of n-butyl acrylate were changed to 100 parts by mass of styrene as the polymerizable vinyl monomer. I. Polymerization was carried out while changing the amount of Solvent Blue 70 to 0.03 parts by mass. Further, when the polymerization conversion reached 92% in the polymerization step, sodium carbonate was added to the aqueous medium to change the pH to 9.5. Otherwise in the same manner as in Example 1, a black toner having an average particle size of 6.8 μm was obtained. This toner was evaluated in the same manner as in Example 1. As a result, generally good results were obtained. Table 3 shows the evaluation results.
[0156]
[Example 3]
In Example 1, the wax was changed to an ester wax having a melting point of 40 ° C., and C.I. I. The operation was performed in the same manner as in Example 1 except that the amount of Solvent Blue 70 was changed to 0.7 parts by mass, to obtain a black toner having an average particle diameter of 6.5 μm. When this toner was evaluated in the same manner as in Example 1, generally good results were obtained. Table 3 shows the evaluation results.
[0157]
[Example 4]
In Example 1, the wax was changed to an ester wax having a melting point of 124 ° C, and C.I. I. The operation was performed in the same manner as in Example 1 except that the amount of Solvent Blue 70 was changed to 0.7 parts by mass, to obtain a black toner having an average particle diameter of 6.4 μm. When this toner was evaluated in the same manner as in Example 1, generally good results were obtained. Table 3 shows the evaluation results.
[0158]
[Example 5]
The procedure of Example 1 was repeated, except that no wax was added, to obtain a black toner having an average particle diameter of 6.7 μm. When this toner was evaluated in the same manner as in Example 1, generally good results were obtained. Table 3 shows the evaluation results.
[0159]
[Example 6]
In Example 1, the average primary particle size was 20 nm, the DBP oil absorption was 130 ml / 100 g, and the BET specific surface area was 87 m.²/ G, volatile matter = 0.6% by mass, except that the carbon black was changed to a black toner having an average particle diameter of 6.8 μm. This toner was evaluated in the same manner as in Example 1. As a result, generally good results were obtained. Table 3 shows the evaluation results.
[0160]
[Example 7]
In Example 1, the average primary particle size of the carbon black was 132 nm, the DBP oil absorption was 154 ml / 100 g, and the BET specific surface area was 41 m.²/ G, volatile matter = 0.6% by mass, except that the carbon black was changed to a black toner having an average particle diameter of 6.7 μm. This toner was evaluated in the same manner as in Example 1. As a result, generally good results were obtained. Table 3 shows the evaluation results.
[0161]
Example 8
In Example 1, C.I. I. The procedure was performed in the same manner as in Example 1 except that the amount of Solvent Blue 70 was changed to 1 part by mass, to obtain a black toner having an average particle diameter of 6.5 μm. When this toner was evaluated in the same manner as in Example 1, the transferability was deteriorated from the end of 5,000 sheets. However, it was at a level without problems. Table 3 shows the evaluation results.
[0162]
[Example 9]
The procedure of Example 1 was repeated, except that 8 parts by mass of a Cu phthalocyanine pigment having a free Cu content of 560 ppm was added instead of carbon black as the colorant, and the average particle size was 6. A cyan toner of 7 μm was obtained. When this toner was evaluated in the same manner as in Example 1, good results were obtained in each case. Table 3 shows the evaluation results.
[0163]
[Example 10]
The procedure of Example 1 was repeated, except that 8 parts by mass of a Cu phthalocyanine pigment having a free Cu content of 2600 ppm was added instead of carbon black as the colorant, and the average particle size was 6. 5 μm cyan toner was obtained. When this toner was evaluated in the same manner as in Example 1, the dispersibility of the colorant deteriorated and the toner consumption increased. However, it was at a level without problems. Table 3 shows the evaluation results.
[0164]
[Example 11]
The procedure of Example 1 was repeated, except that 8 parts by mass of a Cu phthalocyanine pigment having a free Cu content of 8 ppm was added instead of carbon black as the colorant, and the average particle size was 6. A cyan toner of 6 μm was obtained. When this toner was evaluated in the same manner as in Example 1, the dispersibility of the colorant was good, but the toner consumption increased. This is considered to be because the Cu phthalocyanine pigment did not have sufficient coloring properties. However, it was at a level without problems. Table 3 shows the evaluation results.
[0165]
[Comparative Example 1]
Evaluation was performed in the same manner as in Example 1 except that the following toners were used.
・ 100 parts by mass of polyester resin
(Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl)
Condensed polymer of propane and fumaric acid)
・ 10 parts by mass of carbon black
(Average primary particle size = 40 nm, DBP oil absorption = 80 ml / 100 g, BET specific surface area = 55 m²/ G, volatile content = 0.7% by mass)
・ C. I. Solvent Blue 70 2 parts by mass
The resulting material was kneaded with heat, cooled, pulverized, subjected to a spheroidizing treatment, and then classified to obtain 7.0 μm black toner particles.
[0166]
100 parts by mass of the polymer particles and hydrophobic oil-treated silica fine powder (BET specific surface area = 200 m²/ G) 0.7 mass parts was dry-mixed with a Henschel mixer (manufactured by Mitsui Kinzoku Co., Ltd.) to obtain a toner.
[0167]
As a result of evaluation of this toner, fog, scattering, and transferability particularly after printing out 10,000 sheets were remarkably deteriorated. This is presumably because polyester resin was used as the binder. Table 3 shows the evaluation results.
[0168]
[Comparative Example 2]
In Example 1, black toner having an average particle size of 6.8 μm was obtained in the same manner as in Example 1, except that the toner particles were subjected to a sphering process before mixing the hydrophobic oil-treated silica fine powder with the toner particles. A toner was obtained. This toner was evaluated in the same manner as in Example 1. When 5,000 sheets were printed, the evaluation was stopped because fog was significantly deteriorated. Table 3 shows the evaluation results.
[0169]
[Comparative Example 3]
The procedure of Example 1 was repeated, except that the pH in the aqueous medium was changed to 10.5, to obtain a black toner having an average particle diameter of 6.7 μm. In this toner, the proportion of toner having a circularity of less than 0.950 in the toner was increased to 38%. The toner was evaluated in the same manner as in Example 1. At the end of 5,000 sheets, the evaluation was stopped because fog was significantly deteriorated. Table 3 shows the evaluation results.
[0170]
[Comparative Example 4]
The procedure of Example 1 was repeated, except that the pH in the aqueous medium was changed to 4.1, to obtain a black toner having an average particle diameter of 6.9 μm. This toner has an increased circularity standard deviation value of 0.046. The toner was evaluated in the same manner as in Example 1. The evaluation was stopped because the fog significantly deteriorated from the beginning. Table 3 shows the evaluation results.
[0171]
[Comparative Example 5]
Evaluation was performed in the same manner as in Example 1 except that the following toners were used.
・ Styrene-butyl acrylate copolymer 100 parts by mass
(Copolymerization ratio = styrene: n-bryl acrylate = 7: 3, Mn = 50,000)
・ C. I. Solvent Blue 70 2 parts by mass
・ 10 parts by mass of carbon black
(Average primary particle size = 40 nm, DBP oil absorption = 80 ml / 100 g, BET specific surface area = 55 m²/ G, volatile content = 0.7% by mass)
The resulting mixture was kneaded with heat, cooled, pulverized, and classified to obtain 7.0 μm black toner particles.
[0172]
100 parts by mass of the polymer particles and hydrophobic oil-treated silica fine powder (BET specific surface area = 200 m²/ G) 0.7 mass parts was dry-mixed with a Henschel mixer (manufactured by Mitsui Kinzoku Co., Ltd.) to obtain a toner.
[0173]
The toner was evaluated in the same manner as in Example 1. As a result, fog, scattering, and transferability were remarkably deteriorated from the beginning, so the evaluation was stopped. Table 3 shows the evaluation results.
[0174]
[Comparative Example 6]
Evaluation was performed in the same manner as in Example 1 except that the following toners were used.
・ 95 parts by mass of polyester
(Polycondensate of diol of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, fumaric acid, trimellitic acid)
・ Styrene and n-butyl methacrylate copolymer 5 parts by mass
(Copolymerization ratio = styrene: n-bryl acrylate = 7: 3)
・ 2.5 parts by mass of Cu phthalocyanine
(Free Cu content = 560 ppm)
・ C. I. Solvent Blue 70 2 parts by mass
The resulting material was kneaded with heat, cooled, pulverized, and classified to obtain 6.9 μm cyan toner particles.
[0175]
100 parts by mass of the polymer particles and hydrophobic oil-treated silica fine powder (BET specific surface area = 200 m²/ G) 0.7 mass parts was dry-mixed with a Henschel mixer (manufactured by Mitsui Kinzoku Co., Ltd.) to obtain a toner.
[0176]
The toner was evaluated in the same manner as in Example 1. As a result, fog, scattering, and transferability were remarkably deteriorated from the beginning, so the evaluation was stopped. Table 3 shows the evaluation results.
[0177]
[Comparative Example 7]
In Example 1, C.I. I. The same operation as in Example 1 was carried out except that the amount of Solvent Blue 70 was changed to 0.0005 parts by mass, to obtain a black toner having an average particle size of 6.8 μm. When this toner was evaluated in the same manner as in Example 1, the printout image evaluation was not performed because the dispersibility of the colorant was significantly deteriorated. Table 3 shows the evaluation results.
[0178]
[Table 2]

[0179]
[Table 3]

[0180]
【The invention's effect】
As described above, according to the present invention, a toner having high coloring power, low toner consumption, good chargeability, fog, scattering, and transferability is provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an image forming apparatus used in an embodiment of the present invention.
[Explanation of symbols]
1 Photoconductor
2 Toner carrier
3 Transfer material
4 Developer
5 Charging roller
6 blades

Claims (2)

At least a binder resin, a colorant, and a toner containing a Cu phthalocyanine derivative,
The binder resin is at least a styrene polymer or a styrene-based copolymer, and the solubility of the Cu phthalocyanine derivative in styrene at 25 ° C. is 5% by mass or more,
The content of the Cu phthalocyanine derivative is 0.1 to 18% based on the content of the coloring agent,
In the toner, the proportion of toner particles having a circularity of less than 0.950 measured by a flow type particle image measuring device is 1 to 30%, and the circularity standard deviation is 0.010 to 0.040. A toner characterized by the following. At least a polymerizable monomer composition containing a polymerizable vinyl monomer, a colorant, a polymerization initiator, and a Cu phthalocyanine derivative is dispersed in an aqueous dispersion medium, and particles of the polymerizable monomer composition are dispersed. A granulation process to produce
A polymerization step of polymerizing the polymerizable vinyl-based monomer in the particles of the polymerizable monomer composition to form toner particles,
The polymerizable vinyl monomer contains at least styrene,
A solubility of the Cu phthalocyanine derivative in styrene at 25 ° C. of 5% by mass or more,
A method for producing a toner, wherein the polymerization reaction of the polymerizable vinyl monomer from the granulation step to the polymerization step is performed while maintaining at least the pH of the aqueous dispersion medium at 4.5 to 9.0.

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