JP2004021112A - Toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner excellent in low temperature fixability and anti-offsetting property, having high transfer efficiency and ensuring little fog. <P>SOLUTION: The toner comprises at least a bonding resin, a colorant and a releasing agent and has a weight average particle diameter of 3-10 μm, the average circularity of the toner is ≥0.970, the heat absorption peak of the releasing agent in differential thermal analysis (DSC) is within the range of 50-150°C, the releasing agent is a hydrocarbon wax treated with at least a styrenic monomer, the treated wax has two peaks in measurement of the molecular weight of a tetrahydrofuran (THF)-soluble component by gel permeation chromatography (GPC), and when the area of the high molecular side peak is represented by (1) and that of the low molecular side peak by (2), an area ratio satisfies 0.2≤(2)/((1)+(2))≤0.8 (the expression 1). <P>COPYRIGHT: (C)2004,JPO

Description

【００５６】
また、モード円形度は、円形度を０．４０から１．００までを０．０１毎に６１分割し、測定した粒子の円形度をそれぞれの円形度に応じて各分割範囲に割り振り、円形度頻度分布において頻度値が最大となるピークの円形度である。
【００５７】
なお、本発明で用いている測定装置である「ＦＰＩＡ−１０００」は、各粒子の円形度を算出後、平均円形度及びモード円形度の算出に当たって、粒子を得られた円形度によって、円形度０．４０〜１．００を６１分割したクラスに分け、分割店の中心値と頻度を用いて平均円形度及びモード円形度の算出を行う算出法を用いている。しかしながら、この算出法で算出される平均円形度及びモード円形度の各値と、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モード円形度の各値との誤差は、非常に少なく、実質的には無視できる程度のものであり、本発明においては、算出時間の短縮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、一部変更したこのような算出法を用いても良い。
【００５８】
測定手順としては、以下の通りである。
【００５９】
界面活性剤約０．１ｍｇを溶解している水１０ｍｌに、トナー約５ｍｇを分散させて分散液を調整し、超音波（２０ｋＨｚ、５０Ｗ）を分散液に５分間照射し、分散液濃度を５０００〜２万個／μｌとして、前記装置により測定を行い、３μｍ以上の円相当径の粒子群の平均円形度及びモード円形度を求める。
【００６０】
本発明における平均円形度とは、トナーの凹凸の度合いの指標であり、トナーが完全な球形の場合１．０００を示し、トナーの表面形状が複雑になるほど平均円形度は小さな値となる。
【００６１】
なお、本測定において３μｍ以上の円相当径の粒子群についてのみ円形度を測定する理由は、３μｍ未満の円相当径の粒子群にはトナー粒子とは独立して存在する外部添加剤の粒子群も多数含まれるため、その影響によりトナー粒子群についての円形度が正確に見積もれないからである。
【００６２】
本発明のトナーは高画質化のため、より微小な潜像ドットを忠実に再現するため、トナーの重量平均粒径は３〜１０μｍであり、更には４〜９μｍであることがより好ましい。重量平均粒径が３μｍ未満のトナーにおいては、転写効率の低下から感光体上の転写残トナーが多くなり、接触帯電工程での感光体の削れやトナー融着の抑制が難しくなる。さらに、トナー全体の表面積が増えることに加え、粉体としての流動性及び撹拌性が低下し、個々のトナー粒子を均一に帯電させることが困難となることからハーフトーンの均一性が損なわれ、スリーブゴーストも生じやすくなり好ましくない。
【００６３】
一方、トナーの重量平均粒径が１０μｍを超える場合には、文字やライン画像に飛び散りが生じやすく、高解像度が得られにくい。さらに装置が高解像度になっていくと１０μｍ以上のトナーは１ドットの再現が悪化する傾向にある。
【００６４】
また、本発明のトナーは、重量平均粒径／数平均粒径の比が１．４０以下であることが重要であり、より好ましくは１．３５以下である。
【００６５】
重量平均粒径／数平均粒径の比が１．４０より大きいということはトナーの粒度分布が広いことを意味し、選択現像が生じやすくなってしまう。
【００６６】
ここで、トナーの平均粒径および粒度分布はコールターカウンターＴＡ−ＩＩ型あるいはコールターマルチサイザー（コールター社製）等種々の方法で測定可能であるが、本発明においてはコールターマルチサイザー（コールター社製）を用い、個数分布、体積分布を出力するインターフェイス（日科機製）及びＰＣ９８０１パーソナルコンピュータ（ＮＥＣ製）を接続し、電解液は１級塩化ナトリウムを用いて１％ＮａＣｌ水溶液を調整する。例えば、ＩＳＯＴＯＮ　Ｒ−ＩＩ（コールターサイエンティフィックジャパン社製）が使用できる。
【００６７】
測定法としては、前記電界水溶液１００〜１５０ｍｌ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フォン酸塩を０．１〜５ｍｌを加え、更に測定試料を２〜２０ｍｇ加える。試料を懸濁した電解液は超音波分散機で約１〜３分間分散処理を行い、前期コールターマルチサイザーによりアパーチャーとして１００μｍアパーチャーを用いて、２μｍ以上のトナー粒子の体積、個数を測定して体積分布と個数分布とを算出する。それから、体積分布から求めた体積基準の重量平均粒径（Ｄ４）、個数分布から求めた個数基準の長さ平均粒径、即ち数平均粒径（Ｄ１）を求める。後述の実施例においても同様に測定した。
【００６８】
本発明のトナーは離型剤を含有しているが、これまで述べたように離型剤の分散状態は現像性にも影響を与える。この為、本発明のトナーは、該トナーよりも重量平均粒径が小さいトナー（Ｆ）と、該トナーよりも重量平均粒径が大きいトナー（Ｇ）に２分割したとき、示差熱分析に（ＤＳＣ）測定における（Ｆ），（Ｇ）それぞれのトナーの吸熱量をＨｆ、Ｈｇとすると、０．６０＜Ｈｇ／Ｈｆ＜１．５０であることが好ましく、０．８０＜Ｈｇ／Ｈｆ＜１．２０であることがより好ましい。ここで、Ｈｇ／Ｈｆが１に近づくほど離型剤の分散性が良好であることを意味しており、このようなトナーは、本発明における前記処理ワックスを添加することにより得ることが出来る。
【００６９】
Ｈｇ／Ｈｆが０．６０より小さいトナーは離型剤の偏在が多く、離型剤を非常に多く含む粒子が存在することを意味する。このような粒子は、トナー表面への離型剤のしみ出しなどにより帯電の均一性が損なわれやすく、ゴーストを生じやすい。また、このようなトナーは長期使用においてトナー劣化を生じやすく好ましくない。
【００７０】
また、一般的に離型剤を含有するとトナーの帯電性は低下し、粒径の小さなトナーはチャージアップ傾向にあることも知られている。この為、Ｈｇ／Ｈｆが１．５０より大きいと、即ち、大粒径のトナーに離型剤が多く含まれるような場合、トナー全体として、均一な帯電性を有することが出来ず、ゴーストが生じやすくなる。
【００７１】
さらに、Ｈｇ／Ｈｆが１．５０より大きなものは、比較的大きな遊離の離型剤が存在することを意味する場合もあり、このような遊離の離型剤の存在は現像時に悪影響を及ぼすだけであり、この場合においてもスリーブゴーストの悪化、カブリの増大などを招き好ましくない。
【００７２】
このように、０．６０＜Ｈｇ／Ｈｆ＜１．５０とすることで、長期使用においても均一な帯電性を得ることが可能となり、ゴーストの無い高精細な画像を得ることが出来ると考えている。
【００７３】
これまで述べてきたように、粒度分布を特定の値とすることによる選択現像性の抑制と、離型剤の分散性、トナー形状を特定の値とすることによる帯電均一性の相乗効果で低湿環境下においてもスリーブゴーストが抑制でき、且つ、均一なハーフトーン画像を得ることが可能となる。
【００７４】
本発明のトナーには、荷電特性を安定化するために荷電制御剤を配合しても良い。荷電制御剤としては、公知のものが利用でき、特に帯電スピードが速く、且つ、一定の帯電量を安定して維持できる荷電制御剤が好ましい。さらに、トナーを直接重合法を用いて製造する場合には、重合阻害性が低く、水系分散媒体への可溶化物が実質的に無い荷電制御剤が特に好ましい。具体的な化合物としては、ネガ系荷電制御剤としてサリチル酸、アルキルサリチル酸、ジアルキルサリチル酸、ナフト工酸、ジカルボン酸の如き芳香族カルボン酸の金属化合物、アゾ染料あるいはアゾ顔料の金属塩または金属錯体、スルホン酸又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、カリックスアレーン等が挙げられる。ポジ系荷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化合物、グアニジン化合物、ニグロシン化合物、イミダゾール化合物等が挙げられる。
【００７５】
荷電制御剤をトナーに含有させる方法としては、トナー粒子内部に添加する方法と外添する方法がある。これらの荷電制御剤の使用量としては、結着樹脂の種類、他の添加剤の有無、分散方法を含めたトナー製造方法によって決定されるもので、一義的に限定されるものではないが、内部添加する場合は、好ましくは結着樹脂１００質量部に対して０．１〜１０質量部、より好ましくは０．１〜５質量部の範囲で用いられる。また、外部添加する場合、トナー１００質量部に対し、好ましくは０．００５〜１．０質量部、より好ましくは０．０１〜０．３質量部である。
【００７６】
しかしながら、本発明のトナーは、荷電制御剤の添加は必須ではなく、トナーの層圧規制部材やトナー担持体との摩擦帯電を積極的に利用することでトナー中に必ずしも荷電制御剤を含む必要は無い。
【００７７】
本発明のトナーは、粒度や着色剤及び離型剤含有量の異なるトナーを作製した後、混合する方法や、製造段階において着色剤及び離型剤の分散を異ならせる方法が考えられ、製造方法を特に限定するものではない。しかし、一般的に粉砕法で得られるトナー粒子は不定形のものであり、本発明に係わるトナーの必須条件である平均円形度が０．９７０以上という物性を得るためには、機械的・熱的あるいは何らかの特殊な処理を行うことが必要となり、生産性が劣るものとなる。そのため、本発明のトナーは分散重合法、会合凝集法、懸濁重合法など、水中で製造することが好ましい。また、結着樹脂が可溶な有機溶媒中に、結着樹脂、着色剤、離型剤、その他の添加剤を混合して油性成分を調整した後、該油性成分を水性媒体中に懸濁させ、粒子化して懸濁液を調整し、該懸濁液から有機溶媒を除去することにより本発明のトナーを製造することも好ましい形態の一つである。これらの中でも、特に懸濁重合法においては本発明の必須構成要件の諸物性を得やすく、非常に好ましい。
【００７８】
懸濁重合法とは、重合性単量体および着色剤（更に必要に応じて重合開始剤、架橋剤、荷電制御剤、その他の添加剤）を均一に溶解または分散させて重合性単量体系とした後、この重合性単量体系を分散安定剤を含有する連続層（例えば水相）中に適当な撹拌機を用いて分散し同時に重合反応を行わせ、所望の粒径を有するトナーを得るものである。この懸濁重合法で得られるトナー（以後重合トナー）は、個々のトナー粒子形状がほぼ球形に揃っているため、平均円形度が０．９７０以上、モード円形度が０９９以上という本発明に好適な物性要件を満たすトナーが得られやすく、さらにこういったトナーは帯電量の分布も比較的均一となるため高い転写性を有している。
【００７９】
本発明に関わる重合トナーの製造において、重合性単量体系を構成する重合性単量体としては以下のものが挙げられる。
【００８０】
重合性単量体としては、スチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、ｐ−メトキシスチレン、ｐ−エチルスチレン等のスチレン系単量体；アクリル酸メチル、アクリル酸エチル、アクリル酸ｎ−ブチル、アクリル酸イソブチル、アクリル酸ｎ−プロピル、アクリル酸ｎ−オクチル、アクリル酸ドデシル、アクリル酸２−エチルヘキシル、アクリル酸ステアリル、アクリル酸２−クロルエチル、アクリル酸フェニル等のアクリル酸エステル類；メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ｎ−プロピル、メタクリル酸ｎ−ブチル、メタクリル酸イソブチル、メタクリル酸ｎ−オクチル、メタクリル酸ドデシル、メタクリル酸２−エチルヘキシル、メタクリル酸ステアリル、メタクリル酸フェニル、メタクリル酸ジメチルアミノエチル、メタクリル酸ジエチルアミノエチル等のメタクリル酸エステル類；その他のアクリロニトリル、メタクリロニトリル、アクリルアミド等の単量体が挙げられる。これらの単量体は単独、または混合して使用し得る。上述の単量体の中でも、スチレンまたはスチレン誘導体を単独で、あるいは他の単量体と混合して使用することがトナーの現像性及び耐久性の点から好ましい。
【００８１】
本発明に関わる重合トナーの製造においては、重合性単量体系に樹脂を添加して重合しても良い。例えば、単量体では水溶性のため水性懸濁液中では溶解して乳化重合を起こすため使用できないアミノ基、カルボン酸基、水酸基、スルホン酸基、グリシジル基、ニトリル基等、親水性官能基含有の重合性単量体成分をトナー中に導入したい時には、これらとスチレンあるいはエチレン等ビニル化合物とのランダム共重合体、ブロック共重合体、あるいはグラフト共重合体等、共重合体の形にして、あるいはポリエステル、ポリアミド等の重縮合体、ポリエーテル、ポリイミン等、重付加重合体の形で使用が可能となる。こうした極性官能基を含む高分子重合体をトナー中に共存させると、前述のワックス成分を相分離させ、より内包化が強力となり、耐ブロッキング性や現像性の良好なトナーを得ることができる。
【００８２】
これらの樹脂の中でも特にポリエステル樹脂を含有することにより、その効果は大きなものとなる。これは次に述べる理由からと考えている。ポリエステル樹脂は比較的極性の高い官能基であるエステル結合を数多く含むため、樹脂自身の極性が高くなる。その極性のため、水系分散媒中では液滴表面にポリエステルが偏在する傾向が強くなり、その状態を保ちながら重合が進行し、トナーとなる。この為、トナー表面にポリエステル樹脂が偏在する事で表面状態や、表面組成などが均一なものとなり、その結果帯電性が均一となると共に、離型剤の内包性が良好なこととの相乗効果により非常に良好な現像性を得ることが出来る。
【００８３】
また、材料の分散性や定着性、あるいは画像特性の改良等を目的として上記以外の樹脂を単量体系中に添加しても良く、用いられる樹脂としては、例えば、ポリスチレン、ポリビニルトルエンなどのスチレン及びその置換体の単重合体；スチレン−プロピレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−ビニルナフタリン共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸エチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−アクリル酸オクチル共重合体、スチレン−アクリル酸ジメチルアミノエチル共重合体、スチレン−メタアクリル酸メチル共重合体、スチレン−メタアクリル酸エチル共重合体、スチレン−メタアクリル酸ブチル共重合体、スチレン−メタクリル酸ジメチルアミノエチル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルエチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソプレン共重合体、スチレン−マレイン酸共重合体、スチレン−マレイン酸エステル共重合体などのスチレン系共重合体；ポリメチルメタクリレート、ポリブチルメタクリレート、ポリ酢酸ビニル、ポリエチレン、ポリプロピレン、ポリビニルブチラール、シリコーン樹脂、ポリエステル樹脂、ポリアミド樹脂、エポキシ樹脂、ポリアクリル酸樹脂、ロジン、変性ロジン、テルペン樹脂、フェノール樹脂、脂肪族または脂環族炭化水素樹脂、芳香族系石油樹脂などが単独或いは混合して使用できる。これら樹脂の添加量としては、重合性単量体１００質量部に対し１〜２０質量部が好ましい。１質量部未満では添加効果が小さく、一方２０質量部超添加すると重合トナーの種々の物性設計が難しくなる。
【００８４】
さらに、重合性単量体を重合して得られるトナーの分子量範囲とは異なる分子量の重合体を単量体中に溶解して重合すれば、分子量分布の広い、耐オフセット性の高いトナーを得ることが出来る。
【００８５】
本発明で使用される着色剤として、黒色着色剤としては、カーボンブラック、磁性体、イエロー／マゼンタ／シアン着色剤を用い黒色に調色されたものが利用される。
【００８６】
黒色着色剤として磁性体を用いる場合には、カップリング剤で疎水化処理されたものであることが好ましい。磁性体表面を疎水化する際、水系媒体中で、磁性体を一次粒径となるよう分散しながらカップリング剤を加水分解しながら表面処理することによって得られる磁性体が好適である。水系媒体中での疎水化処理方法は、気相中での処理に比べ、磁性体粒子同士の合一が生じにくく、また疎水化処理による磁性体粒子間の帯電反発作用が働き、磁性体はほぼ一次粒子の状態で表面処理されるようになるため、高い均一性の疎水化が達成されるので好ましい。
【００８７】
カップリング剤を水系媒体中で加水分解しながら磁性体表面を処理する方法は、クロロシラン類やシラザン類のようにガスを発生するようなカップリング剤を使用する必要もなく、さらに、これまで気相中では磁性体粒子同士が合一しやすくて、良好な処理が困難であった高粘性のカップリング剤も使用できるようになり、疎水化の効果は絶大である。
【００８８】
本発明に使用できるカップリング剤としては、例えば、シランカップリング剤、チタンカップリング剤が挙げられる。より好ましく用いられるのはシランカップリング剤であり、一般式
ＲｍＳｉＹｎ
［式中、Ｒはアルコキシ基を示し、ｍは１〜３の整数を示し、Ｙはアルキル基、ビニル基、グリシドキシ基、メタクリル基の如き炭化水素基を示し、ｎは１〜３の整数を示す。］
で示されるものである。例えばビニルトリメトキシシラン、ビニルトリエトキシシラン、γ−メタクリルオキシプロピルトリメトキシシラン、ビニルトリアセトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、イソブチルトリメトキシシラン、ジメチルジメトキシシラン、ジメチルジエトキシシラン、トリメチルメトキシシラン、ヒドロキシプロピルトリメトキシシラン、フェニルトリメトキシシラン、ｎ−ヘキサデシルトリメトキシシラン、ｎ−オクタデシルトリメトキシシランを挙げることができる。
【００８９】
特に、式
Ｃ_ｐＨ_２ｐ＋１−Ｓｉ−（ＯＣ_ｑＨ_２ｑ＋１）_３
［式中、ｐは２〜２０の整数を示し、ｑは１〜３の整数を示す］
で示されるアルキルトリアルコキシシランカップリング剤を使用して水系媒体中で磁性体を疎水化処理するのが良い。
【００９０】
上記式におけるｐが２より小さいと、疎水化処理は容易となるが、疎水性を十分に付与することが困難であり、またｐが２０より大きいと、疎水性は十分になるが、磁性体粒子同士の合一が多くなり、トナー中へ磁性体粒子を十分に分散させることが困難になる。
【００９１】
また、ｑが３より大きいと、シランカップリング剤の反応性が低下して疎水化が十分に行われにくくなる。特に、式中のｐが２〜２０の整数（より好ましくは、３〜１５の整数）を示し、ｑが１〜３の整数（より好ましくは、１又は２の整数）を示すアルキルトリアルコキシシランカップリング剤を使用するのが良い。
【００９２】
その処理量は磁性体１００質量部に対して、０．０５〜２０質量部、好ましくは０．１〜１０質量部であり、磁性体の表面積、カップリング剤の反応性などに応じて処理剤の量を調整することが好ましい。
【００９３】
本発明において、水系媒体とは、水を主要成分としている媒体である。具体的には、水系媒体として水そのもの、水に少量の界面活性剤を添加したもの、水にｐＨ調整剤を添加したもの、水に有機溶剤を添加したものが挙げられる。界面活性剤としては、ポリビニルアルコールの如きノンイオン系界面活性剤が好ましい。界面活性剤は、水に対して０．１〜５質量％添加するのが良い。ｐＨ調整剤としては、塩酸の如き無機酸が挙げられる。
【００９４】
撹拌は、例えば撹拌羽根を有する混合機（具体的には、アトライター、ＴＫホモミキサーの如き高剪断力混合装置）で、磁性体微粒子が水系媒体中で、一次粒子になるように充分におこなうのが良い。
【００９５】
こうして得られる磁性体粒子は粒子の凝集が見られず、表面が均一に疎水化処理されているため、トナー材料として用いた場合、トナー中への分散性が非常に良好であり、しかもトナー表面からの露出が無い。
【００９６】
また、本発明のトナーに用いられる磁性体は、鉄、リン、コバルト、ニッケル、銅、マグネシウム、マンガン、アルミニウム、珪素などの元素を含んでも良く、四三酸化鉄、γ−酸化鉄等、酸化鉄を主成分とするものであり、これらを１種または２種以上併用して用いられる。これら磁性体は、窒素吸着法によるＢＥＴ比表面積が２〜３０ｍ^２／ｇが好ましく、特に３〜２８ｍ^２／ｇがより好ましい。また、モース硬度が５〜７のものが好ましい。
【００９７】
本発明のトナーに用られる磁性体は、重合性単量体１００質量部に対して、１０〜２００質量部用いることが好ましく、２０〜１８０質量部用いることが更に好ましい。酸化鉄の配合量が１０質量部未満では現像剤の着色力が乏しく、カブリの抑制も困難であり、一方、２００質量部を超えると、現像剤担持体への磁力による保磁力が強まり現像性が低下したり、個々のトナー粒子への磁性体の均一な分散が難しくなるだけでなく、定着性が低下してしまう。
【００９８】
本発明のトナーをカラートナーとして用いた場合の着色剤としては、公知の染料または／及び顔料が使用される。例えば、カーボンブラック、フタロシアニンブルー、パーマネントブラウンＦＧ、ブリリアントファーストスカーレット、ピグメントグリーンＢ、ローダミン−Ｂベース、スルベントレッド４９、ソルベントレッド１４６、ソルベントブルー３５、キナクリドン、カーミン６Ｂ、ジスアゾエローなどが挙げられ、これらは単独でまたは２種類以上を混合して用いることができる。着色剤の使用量は、重合性単量体１００質量部に対して、２〜２５質量部程度であることが好ましい。
【００９９】
本発明のトナーの製造において使用される重合開始剤としては、重合反応時に半減期０．５〜３０時間であるものを、重合性単量体１００質量部に対し０．５〜２０質量部の添加量で重合反応を行うと、分子量１万〜１０万の間に極大を有する重合体を得、トナーに望ましい強度と適当な溶融特性を与えることができるので好ましい。
【０１００】
重合開始剤としては、従来公知のアゾ系重合開始剤、過酸化物系重合開始剤などがあり、アゾ系重合開始剤としては、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等が例示され、過酸化物系重合開始剤としてはｔ−ブチルパーオキシアセテート、ｔ−ブチルパーオキシラウレート、ｔ−ブチルパーオキシピバレート、ｔ−ブチルパーオキシ−２−エチルヘキサノエート、ｔ−ブチルパーオキシイソブチレート、ｔ−ブチルパーオキシネオデカノエート、ｔ−ヘキシルパーオキシアセテート、ｔ−ヘキシルパーオキシラウレート、ｔ−ヘキシルパーオキシピバレート、ｔ−ヘキシルパーオキシ−２−エチルヘキサノエート、ｔ−ヘキシルパーオキシイソブチレート、ｔ−ヘキシルパーオキシネオデカノエート、ｔ−ブチルパーオキシベンゾエート、α，α’−ビス（ネオデカノイルパーオキシ）ジイソプロピルベンゼン、クミルパーオキシネオデカノエート、１，１，３，３−テトラメチルブチルパーオキシ−２−エチルヘキサノエート、１，１，３，３−テトラメチルブチルパーオキシネオデカノエート、１−シクロヘキシル−１−メチルエチルパーオキシネオデカノエート、２，５−ジメチル−２，５−ビス（２−エチルヘキサノイルパーオキシ）ヘキサン、１−シクロヘキシル−１−メチルエチルパーオキシ−２−エチルヘキサノエート、ｔ−ヘキシルパーオキシイソプロピルモノカーボネート、ｔ−ブチルパーオキシイソプロピルモノカーボネート、ｔ−ブチルパーオキシ２−エチルヘキシルモノカーボネート、ｔ−ヘキシルパーオキシベンゾエート、２，５−ジメチル−２，５−ビス（ベンゾイルパーオキシ）ヘキサン、ｔ−ブチルパーオキシ−ｍ−トルオイルベンゾエート、ビス（ｔ−ブチルパーオキシ）イソフタレート、ｔ−ブチルパーオキシマレイックアシッド、ｔ−ブチルパーオキシ−３，５，５−トリメチルヘキサノエート、２，５−ジメチル−２，５−ビス（ｍ−トルオイルパーオキシ）ヘキサンなどのパーオキシエステル、ベンゾイルパーオキサイド、ラウロイルパーオキサイド、イソブチリルパーオキサイドなどのジアシルパーオキサイド、ジイソプロピルパーオキシジカーボネート、ビス（４−ｔ−ブチルシクロヘキシル）パーオキシジカーボネートなどのパーオキシジカーボネート、１，１−ジ−ｔ−ブチルパーオキシシクロヘキサン、１，１−ジ−ｔ−ヘキシルパーオキシシクロヘキサン、１，１−ジ−ｔ−ブチルパーオキシ−３，３，５−トリメチルシクロヘキサン、２，２−ジ−ｔ−ブチルパーオキシブタンなどのパーオキシケタール、ジ−ｔ−ブチルパーオキサイド、ジクミルパーオキサイド、ｔ−ブチルクミルパーオキサイドなどのジアルキルパーオキサイド、その他としてｔ−ブチルパーオキシアリルモノカーボネート等が挙げられ、必要に応じてこれらの開始剤を２種以上用いることもできる。
【０１０１】
本発明のトナーを製造する際には、架橋剤を添加してもよい。架橋剤の好ましい添加量としては、重合性単量体１００質量部に対して０．００１〜１５質量部である。
【０１０２】
ここで架橋剤としては、主として２個以上の重合可能な二重結合を有する化合物が用いられ、例えば、ジビニルベンゼン、ジビニルナフタレン等のような芳香族ジビニル化合物；例えばエチレングリコールジアクリレート、エチレングリコールジメタクリレート、１，３−ブタンジオールジメタクリレート等のような二重結合を２個有するカルボン酸エステル；ジビニルアニリン、ジビニルエーテル、ジビニルスルフィド、ジビニルスルホン等のジビニル化合物；及び３個以上のビニル基を有する化合物；が単独もしくは混合物として用いられる。
【０１０３】
本発明のトナーを重合法で製造する方法では、一般に上述のトナー組成物などを適宜加えて、ホモジナイザー、ボールミル、コロイドミル、超音波分散機等の分散機によって均一に溶解又は分散させた重合性単量体系を、分散安定剤を含有する水系媒体中に懸濁する。この時、高速撹拌機もしくは超音波分散機のような高速分散機を使用して一気に所望のトナー粒子のサイズとする方が、得られるトナー粒子の粒径がシャープになる。重合開始剤添加の時期としては、重合性単量体中に他の添加剤を添加するとき同時に加えても良いし、水系媒体中に懸濁する直前に混合しても良い。また、造粒直後、重合反応を開始する前に重合性単量体あるいは溶媒に溶解した重合開始剤を加えることも出来る。
【０１０４】
造粒後は、通常の撹拌機を用いて、粒子状態が維持され且つ粒子の浮遊・沈降が防止される程度の撹拌を行えばよい。
【０１０５】
本発明のトナーを製造する場合には、分散安定剤として公知の界面活性剤や有機分散剤・無機分散剤が使用できる。中でも無機分散剤は、有害な超微粉を生じ難く、その立体障害性により分散安定性を得ているので反応温度を変化させても安定性が崩れ難く、洗浄も容易でトナーに悪影響を与え難いので、好ましく使用できる。こうした無機分散剤の例としては、燐酸カルシウム、燐酸マグネシウム、燐酸アルミニウム、燐酸亜鉛等の燐酸多価金属塩、炭酸カルシウム、炭酸マグネシウム等の炭酸塩、メタ硅酸カルシウム、硫酸カルシウム、硫酸バリウム等の無機塩、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、シリカ、ベントナイト、アルミナ等の無機酸化物が挙げられる。
【０１０６】
これら無機分散剤を用いる場合には、そのまま使用しても良いが、より細かい粒子を得るため、水系媒体中にて該無機分散剤粒子を生成させて用いることが出来る。例えば、燐酸カルシウムの場合、高速撹拌下、燐酸ナトリウム水溶液と塩化カルシウム水溶液とを混合して、水不溶性の燐酸カルシウムを生成させることが出来、より均一で細かな分散が可能となる。この時、同時に水溶性の塩化ナトリウム塩が副生するが、水系媒体中に水溶性塩が存在すると、重合性単量体の水への溶解が抑制されて、乳化重合に依る超微粒トナーが発生し難くなるので、より好都合である。重合反応終期に残存重合性単量体を除去する時には障害となることから、水系媒体を交換するか、イオン交換樹脂で脱塩したほうが良い。無機分散剤は、重合終了後酸あるいはアルカリで溶解して、ほぼ完全に取り除くことが出来る。
【０１０７】
また、これらの無機分散剤は、重合性単量体１００質量部に対して、０．２〜２０質量部を単独で使用することが望ましいが、超微粒子を発生し難いもののトナーの微粒化はやや苦手であるので、０．００１〜０．１質量部の界面活性剤を併用しても良い。
【０１０８】
界面活性剤としては、例えばドデシルベンゼン硫酸ナトリウム、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、ステアリン酸ナトリウム、ステアリン酸カリウム等が挙げられる。
【０１０９】
前記重合工程においては、重合温度は４０℃以上、一般には５０〜９０℃の温度に設定して重合を行う。この温度範囲で重合を行うと、内部に封じられるべき離型剤やワックスの類が、相分離により析出して内包化がより完全となる。残存する重合性単量体を消費するために、重合反応終期ならば、反応温度を９０〜１５０℃にまで上げる事は可能である。
【０１１０】
重合トナー粒子は重合終了後、公知の方法によって濾過、洗浄、乾燥を行い、必要により無機微粉体を混合し表面に付着させることで、本発明のトナーを得ることができる。また、製造工程に分級工程を入れ、粗粉や微粉をカットすることも可能である。
【０１１１】
本発明のトナー粒子には、流動性向上剤が外添されていることが画質向上のために好ましい。
【０１１２】
流動性向上剤としては、ケイ酸微粉体，酸化チタン，酸化アルミニウム等の無機微粉体が好ましい。該無機微粉体は、シランカップリング剤，シリコーンオイル又はそれらの混合物の如き疎水化剤で疎水化されていることが好ましい。
【０１１３】
トナー粒子がフルカラー画像形成用の非磁性のカラートナー粒子である場合は、外添剤として、酸化チタン微粒子を使用することが好ましい。
【０１１４】
流動性向上剤は通常、トナー粒子１００質量部に対して０．１〜５質量部使用される。
【０１１５】
トナー粒子と外添剤との混合は、ヘンシェルミキサーの如き混合機を用いるのが良い。
【０１１６】
本発明のトナーを二成分系現像剤に用いる場合は、トナーは磁性キャリアと混合して使用される。磁性キャリアとしては、例えば表面酸化又は未酸化の鉄、ニッケル、銅、亜鉛、コバルト、マンガン、クロム、希土類の如き金属粒子、それらの合金粒子、酸化物粒子及びフェライト等が使用できる。
【０１１７】
上記磁性キャリア粒子の表面を樹脂で被覆した被覆キャリアは、現像スリーブに交流バイアスを印加する現像法において特に好ましい。被覆方法としては、樹脂の如き被覆材を溶剤中に溶解もしくは懸濁せしめて調製した塗布液を磁性キャリアコア粒子表面に付着せしめる方法、磁性キャリアコア粒子と被覆材とを粉体で混合する方法等、従来公知の方法が適用できる。
【０１１８】
磁性キャリアコア粒子表面への被覆材料としては、シリコーン樹脂、ポリエステル樹脂、スチレン系樹脂、アクリル系樹脂、ポリアミド、ポリビニルブチラール、アミノアクリレート樹脂が挙げられる。これらは、単独或いは複数で用いる。
【０１１９】
本発明のトナーと磁性キャリアとを混合して二成分系現像剤を調製する場合、その混合比率は現像剤中のトナー濃度として、２〜１５質量％、好ましくは４〜１３質量％にすると通常良好な結果が得られる。トナー濃度が２質量％未満では画像濃度が低下しやすく、１５質量％を超えるとカブリや機内飛散が発生しやすい。
【０１２０】
次に、本発明のトナーを好適に用いることの出来る画像形成装置の一例を図に沿って具体的に説明する。
【０１２１】
画像形成装置として図３に示すような６００ｄｐｉのレーザービームプリンタ（キヤノン製：ＬＢＰ−８Ｍａｒｋ　ＩＶ）を用意した。この装置は、プロセススピードが８０ｍｍ／ｓとなるように改造されている。図３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５１を用い感光体５６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。なお、帯電ローラーの導電層は体積低効率が１０^２Ω・ｃｍ、抵抗層は１０^７Ω・ｃｍのものを用い、当接圧が２３０Ｎ／ｍとなるように設定した。帯電についで、レーザー光６０で画像部分を露光することにより静電潜像を形成し、一成分非磁性トナー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（体積低効率が５×１０^９Ω・ｃｍ）５７によりトナー画像を転写材５８に転写する。トナー画像をのせた転写材は定着器６３により転写材上に定着される。なお、感光体と転写ローラーとの当接圧力は線圧１３０Ｎ／ｍとなるように設定した。また、一部感光体上に残されたトナーはクリーニング部材５９としたウレタンゴムからなるブレードによりクリーニングされる。
【０１２２】
現像容器５２は図３に示すように、トナー供給体としてトナー担持体５４が感光体５６に当接されている。トナー担持体５４の表面の移動方向及び回転周速は、感光体ドラム表面との接触部分において同方向である。
【０１２３】
トナー担持体にトナーを塗布する手段として、現像部分に塗布ローラー５５が設けられ、該トナー担持体に当接している。接触部分において、塗布ローラー５５表面の移動方向が、トナー担持体の移動方向と反対方向に移動するように回転させることによりトナーをトナー担持体上に塗布する。さらに、該トナー担持体上トナーのコート層制御のために、樹脂コートしたステンレス製ブレード５３が取り付けられている。現像領域では、感光体５６とトナー担持体５４との間に直流の現像バイアスが印加され、トナー担持体上のトナーは静電潜像に応じて感光体５６上に飛翔し可視像となる。
【０１２４】
次に、フルカラー画像を形成するための画像形成方法の一例を図に基づいて説明する。
【０１２５】
図４は、複数画像形成部にて各色のトナー画像をそれぞれ形成し、これを同一転写材に順次重ねて転写するようにした画像形成装置である。ここでは、第１、第２、第３および第４の画像形成部２９_ａ，２９_ｂ，２９_ｃ，２９_ｄが並設されており、各画像形成部はそれぞれ専用の静電潜像保持体、所謂感光ドラム１９_ａ，１９_ｂ，１９_ｃ，および１９_ｄを具備している。感光ドラム１９_ａ乃至１９_ｄはその外周側に潜像形成手段２３_ａ，２３_ｂ，２３_ｃおよび２３_ｄ、現像部１７_ａ，１７_ｂ，１７_ｃおよび１７_ｄ、転写用放電部２４_ａ，２４_ｂ，２４_ｃおよび２４_ｄ、ならびにクリーニング部１８_ａ，１８_ｂ，１８_ｃおよび１８_ｄが配置されている。このような構成にて、まず、第１画像形成部２９_ａの感光ドラム１９_ａ上に潜像形成手段２３_ａによって原稿画像における、例えばイエロー成分色の潜像が形成される。該潜像は現像手段１７_ａのイエロートナーを有する現像剤で可視画像とされ、転写部２４_ａにて、転写材としての記録材Ｓに転写される。上記のようにイエロー画像が転写材Ｓに転写されている間に、第２画像形成部２９_ｂではマゼンタ成分色の潜像が感光ドラム１９_ｂ上に形成され、続いて現像手段１７_ｂのマゼンタトナーを有する現像剤で可視画像とされる。この可視画像（マゼンタトナー像）は、上記の第１画像形成部２９_ａでの転写が終了した転写材Ｓが転写部２４_ｂに搬入されたときに、該転写材Ｓの所定位置に重ねて転写される。以下、上記と同様な方法により、第３、第４の画像形成部２９_ｃ，２９_ｄによってシアン色、ブラック色の画像形成が行われ、上記同一の転写材Ｓに、シアン色、ブラック色を重ねて転写するのである。このような画像形成プロセスが終了したならば、転写材Ｓは定着部２２に搬送され、転写材Ｓ上の画像を定着する。これによって転写材Ｓ上には多色画像が得られるのである。転写が終了した各観光ドラム１９_ａ，１９_ｂ，１９_ｃおよび１９_ｄはクリーニング部１８_ａ，１８_ｂ，１８_ｃおよび１８_ｄにより残留トナーを除去され、引き続き行われる次の潜像形成のために供せられる。なお、上記画像形成装置では、転写材として記録材Ｓの搬送のために、搬送ベルト２５が用いられており、図４において、転写材Ｓは右側から左側へ搬送され、その搬送過程で、各画像形成部２９_ａ，２９_ｂ，２９_ｃおよび２９_ｄにおける各転写部２４_ａ，２４_ｂ，２４_ｃおよび２４_ｄを通過し、転写を受ける。この画像形成方法において、転写材を搬送する搬送手段として加工の容易性及び耐久性の観点からテトロン繊維のメッシュを用いた搬送ベルト及びポリエチレンテレフタレート系樹脂、ポリイミド系樹脂、ウレタン系樹脂の如き薄い誘電体シートを用いた搬送ベルトが利用される。転写材Ｓが第４画像形成部２９^ｄを通過すると、ＡＣ電圧が除電器２０に加えられ、転写材Ｓは除電され、ベルト２５から分離され、その後、定着器２２に入り、画像定着され、排出口２６から排出される。
【０１２６】
なお、この画像形成方法では、その画像形成部にそれぞれ独立した静電潜像保持体を具備しており、転写材はベルト式の搬送手段で、順次、各静電潜像保持体の転写部へ送られるように構成してもよい。また、この画像形成方法では、その画像形成部に共通する静電潜像保持体を具備してなり、転写材は、ドラム式の搬送手段で、静電潜像保持体の転写部へ繰り返し送られて、各色の転写を受けるように構成してもよい。
【０１２７】
次に、着色剤として磁性体を用いた磁性トナーを好適に用いることの出来る画像形成装置の一例を図に沿って具体的に説明する。
【０１２８】
図５において、１は感光ドラムで、その周囲に一次帯電ローラー５、現像器１０、転写帯電ローラー３、クリーナー４、給紙ローラー７等が設けられている。そして感光体ドラム１は一次帯電ローラー５によって−７００Ｖに帯電される（印加電圧は交流電圧−２．０ｋＶｐｐ、直流電圧−７００ＶＤＣ）。そして、レーザー発生装置６によりレーザー光１２を感光体ドラム１に照射することによって露光される。感光体ドラム１上の静電潜像は現像器１０によって一成分磁性トナーで現像され、転写材を介して感光体ドラム１に当接された転写帯電ローラー３により転写材上へ転写される。トナー画像をのせた転写材は搬送ベルト８等により定着器９へ運ばれ転写材上に定着される。また、一部感光体ドラム１上に残されたトナーはクリーナー４によりクリーニングされる。現像器１０は、図５に示すように感光体ドラム１に近接してアルミニウム、ステンレス等、非磁性金属で作られた円筒状のトナー担持体２（以下現像スリーブと称す）が配設され、感光体ドラム１と現像スリーブ２との間隙は図示されないスリーブ／感光体間隙保持部材等により約２３０μｍに維持されている。現像スリーブ内にはマグネットローラー（不図示）が現像スリーブ２と同心的に固定、配設されている。但し現像スリーブ２は回転可能である。マグネットローラーには複数の磁極が具備されており、それぞれ現像、トナーコート量規制、トナーの取り込み／搬送、トナーの吹き出し防止に影響している。現像スリーブ２に付着して搬送される磁性トナー量を規制する部材として、弾性ブレード１３が配設され弾性ブレード１３の現像スリーブ２に対する当接圧により現像領域に搬送されるトナー量が制御される。現像領域では、感光体ドラム１と現像スリーブ２との間に直流及び交流の現像バイアスが印加され、現像スリーブ２上トナーは静電潜像に応じて感光体ドラム１上に飛翔し可視像となる。
【０１２９】
・ＤＳＣ測定
示差走査熱量計（ＤＳＣ測定装置），ＤＳＣ−７（パーキンエルマー社製）を用いて以下のようにして測定する。
【０１３０】
測定試料は２〜１０ｍｇ、好ましくは５ｍｇを精密に秤量する。これをアルミパン中に入れ、リファレンスとして空のアルミパンを用い、測定温度範囲３０〜２００℃の間で、昇温速度１０℃／ｍｉｎで常温常湿下で測定を行う。この昇温過程で、温度３０〜２００℃の範囲におけるＤＳＣ曲線のメインピークの吸熱ピークが得られる。
【０１３１】
・ＧＰＣ測定
ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によるクロマトグラムの分子量は次の条件で測定される。
【０１３２】
４０℃のヒートチャンバー中でカラムを安定化させ、この温度におけるカラムに溶媒としてテトラヒドロフラン（ＴＨＦ）を毎分１ｍｌの流速で流し、試料濃度として０．０５〜０．６質量％に調整した樹脂のＴＨＦ試料溶液を約５０〜２００μｌ注入して測定する。試料の分子量測定にあたっては、試料の有する分子量分布を数種の単分散ポリスチレン標準試料により作成された検量線の対数値とカウント数（リテンションタイム）との関係から算出する。検量線作成用の標準ポリスチレン試料としては、例えば東ソー社製或いはＰｒｅｓｓｕｒｅ　Ｃｈｅｍｉｃａｌ　Ｃｏ．製の分子量が６×１０^２、２．１×１０^３、４×１０^３、１．７５×１０^４、５．１×１０^４、１．１×１０^５、３．９×１０^５、８．６×１０^５、２×１０^６、４．４８×１０^６のものを用い、少なくとも１０点程度の標準ポリスチレン試料を用いるのが適当である。検出器にはＲＩ（屈折率）検出器を用いる。
【０１３３】
カラムとしては、１０^３〜２×１０^６の分子量領域を的確に測定するために、市販のポリスチレンジェルカラムを複数本組み合わせるのが良く、例えば昭和電工社製のｓｈｏｄｅｘ　ＧＰＣ　ＫＦ−８０１，８０２，８０３，８０４，８０５，８０６，８０７の組み合わせや、Ｗａｔｅｒｓ社製のμ−ｓｔｙｒａｇｅｌ　５００、１０^３、１０^４、１０^５の組み合わせを挙げることができる。
【０１３４】
【実施例】
以下、本発明の具体的実施例について説明するが、本発明はこれらの実施例に限定されるものではない。以下の配合における部数は質量部である。
【０１３５】
（処理ワックスの製造法）
スチレンモノマー５２０ｇとノルマルブチルアクリレート１２０ｇに反応開始剤としてジクミルパーオキサイド８０ｇを添加した後、加熱溶融したパラフィンワックスＡ３２８０ｇ中に撹拌しながら滴下し、４時間反応させ、１段階の処理によって処理ワックス１を得た。
【０１３６】
ワックスの種類、スチレンモノマーの比率、不飽和カルボン酸系モノマーの種類や比率、加熱温度等を変え、同様に処理ワックスを得た。比率及び特性を表１、表２に示す。
【０１３７】
【表１】

【０１３８】
【表２】

【０１３９】
（疎水性磁性酸化鉄の製造法）
硫酸第一鉄水溶液中に、鉄イオンに対して１．０〜１．１当量の苛性ソーダ溶液を混合し、水酸化第一鉄を含む水溶液を調製した。該水溶液をｐＨ８に維持しながら、空気を吹き込み、８０〜９０℃で酸化反応を行い、種晶を生成させるスラリー液を調製した。次いで、このスラリー液に当初のアルカリ量（苛性ソーダのナトリウム成分）に対し０．９〜１．２当量となるよう硫酸第一鉄水溶液を加えた後、スラリー液をｐＨ＝８に維持して、空気を吹込みながら酸化反応を進め、酸化反応の終期にｐＨを約６に調整し、酸化反応を終了した。生成した酸化鉄粒子を洗浄、濾過して一旦取り出し、乾燥せずに別の水中に再分散させた後、再分散液のｐＨを調整し、十分撹拌しながらシランカップリング剤［ｎ−Ｃ_１０Ｈ_２１Ｓｉ（ＯＣＨ_３）_３］を磁性酸化鉄１００部に対し２部添加し、十分撹拌した。生成した疎水性酸化鉄粒子を常法により洗浄、濾過、乾燥し、次いで凝集している粒子を解砕処理し、疎水性磁性酸化鉄を得た。
【０１４０】
（トナー製造法）
トナー１の製造
イオン交換水７２０部に０．１Ｍ−Ｎａ_３ＰＯ_４水溶液４５０部、１Ｎ塩酸１９部を投入し６０℃に加温した後、１．０Ｍ−ＣａＣｌ_２水溶液６７．７部を添加して分散安定剤を含むｐＨ＝５．３の水系媒体を得た。
【０１４１】
スチレン　　　　　　　　　　　　　　　　　　　　　　　　　　　７８部
ｎ−ブチルアクリレート　　　　　　　　　　　　　　　　　　　　２２部
ジビニルベンゼン　　　　　　　　　　　　　　　　　　　　　　０．５部
飽和ポリエステル樹脂　　　　　　　　　　　　　　　　　　　　　　５部
負荷電制御剤（ジアルキルサリチル酸アルミ錯化合物）　　　　　　　１部
カーボンブラック　　　　　　　　　　　　　　　　　　　　　　　１０部
上記処方をアトライター（三井三池化工機（株））を用いて均一に分散混合した。この単量体組成物を６０℃に加温し、そこに処理ワックス１　１０部を添加混合溶解し、これに重合開始剤ｔ−ブチル−オキシ２−エチルヘキサノエート４質量部を溶解した。
【０１４２】
前記水系媒体中に上記重合性単量体系を投入し、６０℃，Ｎ_２雰囲気下においてＴＫ式ホモミキサー（特殊機化工業（株））にて１０，０００ｒｐｍで１５分間撹拌し、造粒した。その後パドル撹拌翼で撹拌しつつ、８０℃で８時間反応させた。反応終了後、懸濁液を冷却し、塩酸を加えてｐＨ＝２以下で分散剤を溶解し、分散剤を溶解し、濾過、水洗、乾燥してトナー粒子１を得た。
【０１４３】
このトナー粒子１００部と、一次粒径１２ｎｍのシリカにヘキサメチルジシラザンで処理をした後シリコーンオイルで処理し、処理後のＢＥＴ値が１２０ｍ^２／ｇの疎水性シリカ微粉体１．０部をヘンシェルミキサー（三井三池化工機（株））を用い混合し、重量平均粒径が６．９μｍのトナー１を調製した。
【０１４４】
得られたトナー１、２００ｇを風力分級を行い（エルボージェット分級装置　ＥＪ−Ｌ−３：日鉄鉱業製）、トナー（Ｆ）を９８ｇトナー（Ｇ）を１０１ｇ得た。得られたトナー（Ｆ）、（Ｇ）それぞれについて離型剤の吸熱量の測定を行ったところ、Ｈｇ／Ｈｆは０．９８であった。トナー１の物性を表３に示す。
【０１４５】
トナー２〜４の製造
処理ワックス１を処理ワックス２〜４に変えたこと以外はトナー１の製造と同様にして、トナー２〜４を得た。トナー２〜４の物性を表３に示す。
【０１４６】
トナー５の製造
処理ワックス１を処理ワックス６に変えたこと以外はトナー１の製造と同様にして、トナー５を得た。トナー５の物性を表３に示す。
【０１４７】
トナー６の製造
処理ワックス１を処理ワックス８に変えたこと以外はトナー１の製造と同様にして、トナー６を得た。トナー６の物性を表３に示す。
【０１４８】
トナー７〜１０の製造
処理ワックス１を処理ワックス１１〜１４に変えたこと以外はトナー１の製造と同様にして、トナー７〜１０を得た。トナー７〜１０の物性を表３に示す。
【０１４９】
トナー１１の製造
処理ワックス１の量を０．７部としたこと以外はトナー１の製造と同様にしてトナー１１を得た。トナー１１の物性を表３に示す。
【０１５０】
トナー１２の製造
処理ワックス１の量を３１部としたこと以外はトナー１の製造と同様にしてトナー１２を得た。トナー１２の物性を表３に示す。
【０１５１】
トナー１３の製造
処理ワックス１を処理ワックス５に変えたこと以外はトナー１の製造と同様にして、トナー１３を得た。トナー１３の物性を表３に示す。
【０１５２】
トナー１４の製造
処理ワックス１を処理ワックス７に変えたこと以外はトナー１の製造と同様にして、トナー１４を得た。トナー１４の物性を表３に示す。
【０１５３】
トナー１５〜１６の製造
処理ワックス１を処理ワックス９〜１０に変えたこと以外はトナー１の製造と同様にして、トナー１５〜１６を得た。トナー１５〜１６の物性を表３に示す。
【０１５４】
トナー１７の製造
処理ワックス１を処理ワックス１５に変えたこと以外はトナー１の製造と同様にして、トナー１７を得た。トナー１７の物性を表３に示す。
【０１５５】
トナー１８の製造
処理ワックス１をパラフィンワックスＡに変えたこと以外はトナー１の製造と同様にして、トナー１８を得た。トナー１８の物性を表３に示す。
【０１５６】
トナー１９の製造
イオン交換水７２０部に０．１Ｍ−Ｎａ_３ＰＯ_４水溶液を２２６部、１Ｎ塩酸を１９部投入し６０℃に加温した後、１．０Ｍ−ＣａＣｌ_２水溶液３３．９部を添加して分散安定剤を含むｐＨ＝５．３水系媒体を得たこと以外はトナー１の製造と同様にして、トナー１９を得た。トナー１９の物性を表３に示す。
【０１５７】
トナー２０の製造
カーボンブラック１０部を疎水性磁性酸化鉄９０部に変えたこと以外はトナー１の製造と同様にして、トナー２０を得た。トナー２０の物性を表３に示す。
【０１５８】
トナー２１の製造
スチレン／ｎ−ブチルアクリレート共重合体　　　　　　　　　　１００部
（質量比７８／２２）
飽和ポリエステル樹脂　　　　　　　　　　　　　　　　　　　　　　５部
負荷電制御剤（モノアゾ染料系のＦｅ化合物）　　　　　　　　　　　４部
カーボンブラック　　　　　　　　　　　　　　　　　　　　　　　１０部
処理ワックス１　　　　　　　　　　　　　　　　　　　　　　　　１０部
上記材料をブレンダーにて混合し、１１０℃に加熱した二軸エクストルーダーで溶融混練し、冷却した混練物をハンマーミルで粗粉砕し、粗粉砕物をジェットミルで微粉砕後、得られた微粉砕物を風力分級してトナー粒子２０を得た。このトナー粒子２０を１００部に対して、トナー１の製造で使用したシリカ１．０部をヘンシェルミキサーを用い混合し、重量平均粒径が８．４μｍのトナー２１を調製した。トナー２１の物性を表３に示す。
【０１５９】
トナー２２の製造
トナー２１の製造で得たトナー粒子２１をハイブリタイザーを用い、６０００回転で３分間の処理を２回行いトナー粒子２２を得た。このトナー粒子１００部に対してトナー１の製造で使用したシリカ１．０部を加え、ヘンシェルミキサーを用い混合しトナー２２を調整した。トナー２２の物性を表３に示す。
【０１６０】
トナー２３の製造
スチレン　　　　　　　　　　　　　　　　　　　　　　　　　　　６５部
２−エチルヘキシルアクリレート　　　　　　　　　　　　　　　　３５部
ジビニルベンゼン　　　　　　　　　　　　　　　　　　　　　　０．８部
カーボンブラック　　　　　　　　　　　　　　　　　　　　　　　１０部
飽和ポリエステル樹脂　　　　　　　　　　　　　　　　　　　　　　８部
不飽和ポリエステル樹脂　　　　　　　　　　　　　　　　　　　　　２部
上記処方をアトライターを用い均一に分散した。その後、６０℃に加温し、トナー１の製造で用いた処理ワックス１を１０部、２，２’−アゾビスイソブチロニトリル３．５部を添加し、溶解した。
【０１６１】
次いで、リン酸三カルシウム４質量％の水性コロイド溶液６５０部を６０℃に加温した後、上記の重合性単量体系１３４．３部を添加し、ＴＫホモミキサーを用いて室温にて、回転数１００００ｒｐｍで３分間乳化分散させた。
【０１６２】
その後、窒素雰囲気下にて撹拌を続けながら、８５℃で１０時間反応を行った後、室温まで冷却し、トナー粒子分散液を得た。
【０１６３】
次に、スチレン１３．０部、２−エチルヘキシルアクリレート７．０部、２，２’−アゾビスイソブチロニトリル０．４部、ジビニルベンゼン０．２部、ラウリル硫酸ナトリウム０．１部を水２０部に投入し、超音波ホモジナイザーを用い分散させ、水乳濁液４０．７部を得た。
【０１６４】
これを、前記トナー粒子分散液中に滴下し、粒子を膨潤させた。その後、窒素雰囲気下にて撹拌を行い、８５℃で１０時間反応を行った。その後、懸濁液を冷却し、トナー１と同様に洗浄、濾過、乾燥し、次いで風力分級を行いトナー粒子２３を得た。
【０１６５】
このトナー粒子２３を１００部と、トナー１の製造で使用したシリカ１．０部とをヘンシェルミキサーを用い混合し、重量平均粒径が７．８μｍのトナー２３を調製した。トナー２３の物性を表３に示す。
【０１６６】
【表３】

【０１６７】
〔実施例１〕
画像形成装置として、ＬＢＰ−８Ｍａｒｋ　ＩＶを改造し、概ね図３に示されるものを用いた。
【０１６８】
静電荷像坦持体の電位は、暗部電位Ｖｄ＝−５８０Ｖ、明部電位ＶＬ＝−１５０Ｖとした。また、トナー担持体として、カーボンブラックを分散して抵抗を調節したシリコーンゴムからなる中抵抗ゴムローラ（直径１６ｍｍ、硬度ＡＳＫＥＲ　Ｃ４５度、抵抗１０^５Ω・ｃｍ）を用いて感光体に当接させた。このときの現像当接幅は約３ｍｍとなるようにした。該トナー担持体の周速は感光体周速（８０ｍｍ／ｓｅｃ）に対して順方向に１５０％のスピード（１２０ｍｍ／ｓｅｃ）とした。トナー塗布部材として発泡ウレタンゴムからなる塗布ローラーを設け、該トナー担持体に当接させた。塗布ローラーには、約−５５０Ｖの電圧を印加した。さらに、トナー規制部材として樹脂コートしたステンレス製ブレードを３９．２Ｎ／ｍ（４０ｇ／ｃｍ）の線圧で当接させた。また、現像時の印加電圧を直流成分（−４５０Ｖ）のみとした。
【０１６９】
帯電帯電時の印加電圧を直流成分（−１．２ｋＶ）、転写時の印加電圧を直流成分（−１．５ｋＶ）とした。
【０１７０】
最初に、トナー１をカートリッジに１００ｇ充填し、常温常湿環境下（２３℃，６０％ＲＨ）及び低温低湿環境下（１５℃，１０％ＲＨ）において、印字率３％の横線のみからなる画像パターンで６０００枚の画出し試験を行った。なお、転写材としては７５ｇ／ｍ^２の紙を使用した。
【０１７１】
その結果、トナー１は初期、及び、６０００枚の画出し後において高い転写性を示し、ゴーストも無く、非画像部へのカブリのないハーフトーン再現性に優れた良好な画像が得られた。また、低温定着性、耐ホットオフセット性にも優れ、広い定着温度幅を取ることが出来た。常温常湿環境下での評価結果を表４に、低温低湿環境下での評価結果を表５に示す。
【０１７２】
本発明の実施例、ならびに、比較例中に記載の評価項目とその判断基準について述べる。
【０１７３】
＜定着温度幅＞
ＬＢＰ−８Ｍａｒｋ　ＩＶの改造機を用いて定着試験を行った。このときの画像面積比率は２５％であり、単位面積当たりの、トナー載り量は、０．７ｍｇ／ｃｍ^２に設定した。定着開始温度とオフセット開始温度の測定は、定着器の設定温度を１２０〜２１０℃迄の温度範囲で５℃おきに温度調節して、各々の温度で定着画像を出力し、得られた定着画像を４．９ｋＰａ（５０ｇ／ｃｍ^２）の荷重をかけたシルボン紙で摺擦し、摺擦前後の濃度低下率が１０％以下となる定着温度を定着開始温度とした。また定着開始温度から更に設定温度を上げて行き、目視で高温オフセットの発生した温度をオフセット開始温度とした。
【０１７４】
＜転写効率＞
転写効率は、ベタ黒画像転写後の感光体上の転写残トナーをマイラーテープによりテーピングしてはぎ取り、紙上に貼ったもののマクベス濃度の値をＣ、転写後定着前のトナーの載った紙上にマイラーテープを貼ったもののマクベス濃度をＤ、未使用の紙上に貼ったマイラーテープのマクベス濃度をＥとした時、近似的に以下の式で計算した。
【０１７５】
【数２】

【０１７６】
上記の計算結果から得られた転写効率を以下の基準で判断した。
Ａ：転写効率が９６％以上。
Ｂ：転写効率が９２％以上、９６％未満。
Ｃ：転写効率が８９％以上、９２％未満。
Ｄ：転写効率が８９％未満。
【０１７７】
＜カブリ＞
カブリの測定は、東京電色社製のＲＥＦＬＥＣＴＭＥＴＥＲ　ＭＯＤＥＬ　ＴＣ−６ＤＳを使用して測定した。フィルターは、グリーンフィルターを用い、カブリは下記の式より算出した。
【０１７８】
カブリ（反射率）（％）＝
標準紙上の反射率（％）−サンプル非画像部の反射率（％）
【０１７９】
なお、カブリの判断基準は以下の通り。
Ａ：非常に良好（１．５％未満）
Ｂ：良好（１．５％以上乃至２．５％未満）
Ｃ：普通（２．５％以上乃至４．０％未満）
Ｄ：悪い（４％以上）
【０１８０】
＜ゴースト＞
ゴーストの判断基準は、図１に示す画像を出力し、以下の基準により目視で判断したものである。
Ａ：ゴーストは発生していない。
Ｂ：軽微なゴーストが発生しているものの、良好な画像。
Ｃ：ゴーストは発生しているものの、実用的には問題の無い画質。
Ｄ：ゴーストが悪く、実用上好ましくない画像。
【０１８１】
＜画質＞
画質の判断基準は、画像の均一性、細線再現性を総合的に評価したものである。なお、画像の均一性はベタ黒画像、ならびにハーフトーン画像の均一性で判断を行う。
Ａ：細線再現性、画像の均一性に優れ、鮮明な画像。
Ｂ：細線再現性、画像の均一性が若干劣るものの、良好な画像。
Ｃ：実用的には問題の無い画像。
Ｄ：細線再現性、画像の均一性が悪く、実用上好ましくない画像。
【０１８２】
〔実施例２〜１４〕
トナーとして、トナー２〜１２、２２、２３を使用し、実施例１と同様の条件で画出し試験及び耐久性評価を行った。その結果、初期の画像特性も問題なく、印字６０００枚までいずれも大きな問題の無い結果が得られた。常温常湿環境下での評価結果を表４に、低温低湿環境下での評価結果を表５に示す。
【０１８３】
〔実施例１５〕
画像形成装置として、ＬＢＰ−１７６０を改造し、概ね図５に示される構造のものを用いた。
【０１８４】
静電荷像担持体（感光体ドラム１）の電位は、暗部電位Ｖ_ｄ＝−６５０Ｖ、明部電位Ｖ_Ｌ＝−１３０Ｖとした。また、静電荷像担持体と現像スリーブとの間隙は２７０μｍとし、トナー担持体として下記の構成の層厚約７μｍ、ＪＩＳ中心線平均粗さ（ＲＡ）１．０μｍの樹脂層を、表面をブラストした直径１６φのアルミニウム円筒上に形成した現像スリーブを使用し、現像磁極８５ｍＴ（８５０ガウス）、トナー規制部材として厚み１．０ｍｍ、自由長０．５ｍｍのウレタン製ブレードを３９．２Ｎ／ｍ（４０ｇ／ｃｍ）の線圧で当接させた。
フェノール樹脂　　　　　　　　　　　　　　　　　　　　　　　　１００部
グラファイト（粒径約７μｍ）　　　　　　　　　　　　　　　　　　９０部
カーボンブラック　　　　　　　　　　　　　　　　　　　　　　　　１０部
【０１８５】
次いで、現像バイアスとして直流バイアス成分Ｖ_ｄｃ＝−４５０Ｖ、重畳する交流バイアス成分Ｖ_ｐ−ｐ＝１６００Ｖ、Ｆ＝２２００Ｈｚを用いた。また、現像スリーブの周速は感光体周速（９４ｍｍ／ｓｅｃ）に対して順方向に１１０％のスピード（１０３ｍｍ／ｓｅｃ）とした。また、転写バイアスは直流１．５ｋＶとした。
【０１８６】
定着方法としては、ＬＢＰ−１７６０のオイル塗布機能のない、フィルムを介してヒーターにより加熱加圧定着する方式の定着装置を用いた。この時加圧ローラーはフッ素系樹脂の表面層を有するものを使用し、ローラーの直径は３０ｍｍであった。また、定着温度は１８０℃、ニップ幅を７ｍｍに設定した。
【０１８７】
定着温度幅の評価については、上記定着装置を用いたこと以外は実施例１と同様にして行った。
【０１８８】
トナー２０をカートリッジに１００ｇ充填し、常温常湿環境下（２３℃，６０％ＲＨ）及び低温低湿環境下（１５℃，１０％ＲＨ）において、印字率３％の横線のみからなる画像パターンで６０００枚の画出し試験を行った。なお、転写材としては７５ｇ／ｍ^２の紙を使用した。
【０１８９】
その結果、トナー２０は初期、及び、６０００枚の画出し後において高い転写性を示し、ゴーストも無く、非画像部へのカブリのないハーフトーン再現性に優れた良好な画像が得られた。また、低温定着性、耐ホットオフセット性にも優れ、広い定着温度幅を取ることが出来た。常温常湿環境下での評価結果を表４に、低温低湿環境下での評価結果を表５に示す。
【０１９０】
〔比較例１〜８〕
トナーとして、トナー１３〜１９、２１を使用し、実施例１と同様の条件で画出し試験及び耐久性評価を行った。その結果、耐久試験と共に転写効率の低下、カブリ、ゴースト、画質の悪化が生じた。また、トナー１４、１５、１７については定着温度幅が狭かった。
【０１９１】
【表４】

【０１９２】
【表５】

【０１９３】
【発明の効果】
本発明のトナーを用いることにより、低温定着性、耐オフセット性に優れ、多数枚耐久においても良好なトナー性能が維持されると共に、ゴースト、カブリの無い高精細な画像を長期間安定して与えることが出来る。
【図面の簡単な説明】
【図１】画像上に発生するゴーストの概念図である。
【図２】高分子側のピーク面積▲１▼と低分子側のピーク面積▲２▼の概念図である。
【図３】本発明の実施に好適な画像形成装置の一例を示す図である。
【図４】フルカラー画像を形成するための画像形成方法の一例を示す図である。
【図５】磁性トナーを好適に用いることのできる画像形成装置の一例を示す図である。
【符号の説明】
５１　帯電ローラー（接触帯電部材）
５２　現像装置
５４　現像スリーブ（トナー担持体）
５５　撹拌部材
５６　感光体（像担持体、被帯電体）
５７　転写ローラー（転写部材）
５９　クリーナー
６３　定着装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a toner for visualizing an electrostatic latent image in an image forming method such as an electrophotographic method, an electrostatic recording method, a magnetic recording method, and a toner jet method, an image forming method using the toner, and a process cartridge. About.
[0002]
[Prior art]
Although many methods are known as electrophotography, generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is developed with toner. Then, the toner image is transferred to a transfer material, such as paper, as necessary, and then the toner image is fixed on the transfer material by heat, pressure, or the like to obtain a copy. Further, the toner particles remaining on the photoconductor without being transferred onto the transfer material are removed from the photoconductor by the cleaning process, and the above-described process is repeated.
[0003]
In recent years, in such copying apparatuses, miniaturization, weight reduction, high speed, high resolution, and high reliability have been strictly pursued, and as a result, the performance required of the toner has become higher.
[0004]
As one means for satisfying this requirement, the particle size of the toner has been reduced, and JP-A-1-112253, JP-A-1-191156, JP-A-2-214156, and JP-A-2-284158. JP-A-3-181952 and JP-A-4-162048 propose toners having a specific particle size distribution and a small particle size.
[0005]
The most important performance required of the toner in digital printers and copying of high-resolution images is fixing performance. Various methods and apparatuses have been developed for the fixing step, but the most common method at present is a heat compression method using a heat roller. The pressure heating method using a heating roller performs fixing by allowing the toner image surface of the sheet to be fixed to pass through the surface of the heat roller having a surface formed of a material having a releasing property with respect to the toner under pressure. It is. In this method, since the surface of the heat roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the thermal efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. And is very effective in high speed electrophotographic copiers.
[0006]
Conventionally, it has been known that a wax is contained as a release agent in a toner in order to improve the offset resistance at low and high temperatures in fixing. For example, techniques disclosed in JP-A-52-3304, JP-A-52-3305, and JP-A-57-52574 are disclosed. However, while these waxes improve the anti-offset properties, they have also deteriorated the anti-blocking properties and the developability.
[0007]
In recent years, it has been required to prevent the offset phenomenon, and at the same time, it is required to realize a fixing method that has a short wait time and low power consumption in fixing. There is a need for a design that can achieve fixing at a lower temperature. For example, JP-A-51-14333, JP-A-57-14852, JP-A-58-97056, JP-A-60-247250, JP-A-4-362953, and JP-A-6-36295. In JP 230600 and JP-A-8-030036, solid silicone varnishes, higher fatty acid waxes, higher alcohol waxes, plant natural waxes (carnauba, rice), and montan ester waxes are used as release agents. Proposed.
[0008]
However, when a wax, which is such a low softening point release agent, is contained in the toner as a release agent, the development characteristics, chargeability, durability, and storability of the toner are likely to be adversely affected. Further, these waxes are hard to be uniformly dispersed in the toner, and the wax which is free or unevenly distributed in the toner tends to have a bad influence on developability, durability and the like.
[0009]
Further, JP-A-8-278657, JP-A-8-334919, and JP-A-8-334920 disclose two kinds of wax components in order to obtain a toner having excellent low-temperature fixability and offset resistance. It has been proposed to include it in toner. Japanese Patent Application Laid-Open No. 7-281478 discloses that a polypropylene-based resin and an acid-modified polyethylene-based resin are used as a release agent for toner in order to lower the minimum fixing temperature and increase the hot offset temperature. Proposed.
[0010]
Further, JP-A-58-63947, JP-A-63-191817, and JP-A-9-73185 propose a method of modifying a polyolefin or polyethylene with a styrene monomer or an unsaturated carboxylic acid monomer. ing.
[0011]
However, even if any of these release agents is used, it is not enough to achieve both low-temperature fixability, high-temperature offset resistance, and toner durability stability, and further improvement has been desired.
[0012]
On the other hand, as described above, as the direction of recent technology, a higher resolution and higher definition developing method has been required, and in order to respond to such a demand, progress has been made in the direction of reducing the particle size of the toner. However, as the toner particle size becomes smaller, uniform dispersion of the release agent becomes an important technique. That is, unless a uniform amount of the release agent is contained in the fine individual toner particles in a uniform state, the image characteristics and the stability thereof tend to be more remarkably reduced. This is simply because the particle size of the toner becomes small, and the cohesive force applied to the toner particles in the transfer process increases the adhesion of the toner particles to the photoreceptor (mirror, van der Waals, etc.). As a result, in addition to the increase in transfer residual toner, a reduction in toner particle size is unavoidably accompanied by an increase in charge amount and deterioration of fluidity, so that a difference in dispersibility becomes a large difference in physical properties, which tends to appear. This is because the ratio of fog or toner having poor transferability increases. In addition, a toner having poor dispersibility of the release agent and a toner having a large amount of free release agent are likely to have a non-uniform charge amount of the toner and are likely to cause selective development. This causes development in which so-called shading unevenness occurs. Further, it is difficult for such a toner to obtain a uniform image, especially in a halftone image, and such a phenomenon tends to occur remarkably in a low-humidity environment where a difference in chargeability tends to occur.
[0013]
Conventional toners are produced by melt-kneading a binder resin, a colorant, and the like, uniformly dispersing them, pulverizing them with a fine pulverizer, classifying them with a classifier, and producing toner having a desired particle size (pulverization method). However, there is a limitation on the material selection range for reducing the toner particle size. For example, the resin colorant dispersion must be sufficiently brittle and capable of being pulverized with economically available manufacturing equipment. From this requirement, in order to make the resin colorant dispersion brittle, when the resin colorant dispersion is actually finely pulverized at a high speed, particles having a wide particle size range are easily formed, and in particular, a relatively large proportion of fine particles ( The problem is that excessively pulverized particles are included in this. Further, such a highly brittle material often undergoes further pulverization or powdering when used as a developing toner in a copying machine or the like.
[0014]
In the pulverization method, it is difficult to completely and uniformly disperse the release agent into the resin because the compatibility between the binder resin and the release agent is poor as described above, and the dispersibility is poor. Tends to have a large amount of release agent on the differential side, causing ghost, fog increase, and image density decrease. Further, in the pulverization method, a free release agent is easily generated, and problems remain in the fluidity of the toner and the charging stability under a severe environment.
[0015]
On the other hand, in recent years, a large number of technical disclosures have been made regarding a toner obtained by a polymerization method (hereinafter, a polymerization toner). It is considered that the polymerization method can easily make the toner into fine particles as compared with the pulverization method, and since the obtained toner is spherical, it has excellent fluidity and is advantageous for high image quality.
[0016]
However, also in the polymerization method, the release agent component in the polymerizable monomer is in an agglomerated state, and the amount of the release agent component in each generated toner varies, or the release agent component is located at the center of the toner. Have not been obtained which can satisfy the charging characteristics, fixing property, fluidity and blocking resistance of each toner due to aggregation of the toner.
[0017]
In order to solve the above problems, Japanese Patent No. 2744335 discloses a polymerizable composition comprising a polymerizable monomer, an unmodified wax (low-molecular-weight polyolefin) and a graft-modified wax (polyolefin-grafted resin). There has been proposed a method for producing a toner in which the unmodified wax is once dissolved by heating and then cooled to finely disperse the unmodified wax in the polymerizable composition, followed by suspension polymerization. In Japanese Patent Application Laid-Open No. 5-303232, after kneading a carbon black graft polymer and a wax, the wax is dispersed in a fine particle form in a matrix of the carbon black graft polymer, and then uniformly dispersed in the polymerizable monomer. Technical disclosures have been made on a method for producing colored fine particles to be dispersed and subjected to suspension polymerization.
[0018]
However, the present inventors have studied that, even when the wax and the method as described above are used, although the offset resistance and the fixing property can be improved to some extent, it is difficult to sufficiently prevent the generation of free wax. Therefore, the toner did not satisfy the chargeability, durability, and environmental stability required for a high-definition image. In addition, in the above-described method, the steps are complicated, for example, heating and melting the wax once to precipitate it by cooling, which is not preferable because it leads to an increase in cost and a decrease in productivity.
[0019]
[Problems to be solved by the invention]
An object of the present invention is to provide a toner which is excellent in low-temperature fixability and offset resistance, has high transfer efficiency, and has little fog. It is still another object of the present invention to provide a toner capable of obtaining a high-quality image with uniform halftone and no ghost even when used for a long time.
[0020]
[Means for Solving the Problems]
The object of the present invention is achieved by the following.
[0021]
That is, a toner having a weight average particle diameter of at least 3 to 10 μm containing at least a binder resin, a colorant and a release agent,
The average circularity of the toner is 0.970 or more;
The release agent has an endothermic peak in the differential thermal analysis (DSC) measurement in the range of 45 to 120 ° C;
The release agent is at least a hydrocarbon wax treated with a styrene-based monomer (hereinafter referred to as a treated wax), and the treated wax is measured by gel permeation chromatography (GPC) of a soluble portion of tetrahydrofuran (THF). Assuming that the polymer has two peaks in the molecular weight measurement, the area of the peak on the high molecular side is (1) and the area of the peak on the low molecular side is (2), the area ratio is:
0.2 ≦ (2) / ((1) + (2)) ≦ 0.8 (Equation 1)
Is satisfied.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail by way of preferred embodiments of the present invention. The present inventors have found that the above object can be achieved by using at least a treated wax treated with a styrene-based monomer as a release agent as a raw material of a toner. Normally, hydrocarbon wax has low interfacial adhesion to toner resin, and free wax is easily generated. The free hydrocarbon wax is fused to the cleaning blade and the photoreceptor, thereby deteriorating the developing property and the cleaning property. Further, the self-aggregation property and the adhesive force are high, and the fluidity of the toner is deteriorated. For this reason, there have been problems such as fogging due to lowering of the rising speed of charging and charging failure, sleeve contamination of the developing device, and carrier contamination in two-component development.
[0023]
Therefore, the present inventors have considered to improve the interfacial adhesion and prevent the desorption by treating the hydrocarbon wax so as to be easily compatible with the toner resin component. As a result of diligent studies, it has been found that those obtained by treating hydrocarbon wax with at least a styrene-based monomer for compatibility with binder resin, dispersibility when incorporated in toner, fluidity, developability and fixability It was found to be the most effective method. Details of this effect are not clear, but are probably due to the following reasons.
[0024]
Although the treated wax of the present invention uses a styrene-based monomer, the molecular structure of the portion of the hydrocarbon wax modified by the treatment in which the copolymer mainly composed of the styrene-based monomer is formed is similar to that of the binder resin. Therefore, it is considered that the mutual compatibility is increased and the detachment of the wax is less likely to occur. As a result, the fusion of the wax to the cleaning blade and the photoreceptor, poor charging, and the like were eliminated, and excellent developing performance and cleaning performance without fog could be maintained.
[0025]
The treated wax used in the present invention will be described.
[0026]
As the treated wax used in the present invention, a hydrocarbon wax treated with a styrene monomer can be used, and a hydrocarbon wax treated with a styrene monomer and an unsaturated carboxylic acid monomer can also be preferably used. The treated wax functions as a release agent in the toner.
[0027]
As the hydrocarbon wax before the treatment, a hydrocarbon wax having a softening point of 45 to 120 ° C can be preferably used, and a paraffin hydrocarbon wax is particularly preferred. As the paraffin hydrocarbon wax, known waxes such as natural paraffin wax, synthetic paraffin wax, microcrystalline wax, and Fischer-Tropsch wax can be used.
[0028]
Examples of the styrene monomer include styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, p-methylstyrene, p-methoxystyrene, and m-methylstyrene.
[0029]
Unsaturated carboxylic acid monomers include methyl acrylate, ethyl acrylate, butyl acrylate, sec-butyl acrylate, isobutyl acrylate, propyl acrylate, isopropyl acrylate, 2-octyl acrylate, dodecyl acrylate, acrylic Stearyl acid, hexyl acrylate, isohexyl acrylate, phenyl acrylate, 2-chlorophenyl acrylate, diethylaminoethyl acrylate, 3-methoxybutyl acrylate, diethylene glycol ethoxylate acrylate, 2,2,2-trifluoroethyl acrylate Acrylates such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, isobutyl methacrylate, propyl methacrylate, methacrylic acid Sopropyl, 2-octyl methacrylate, dodecyl methacrylate, stearyl methacrylate, hexyl methacrylate, decyl methacrylate, phenyl methacrylate, 2-chlorohexyl methacrylate, diethylaminoethyl methacrylate, 2-hexylethyl methacrylate, 2 methacrylate Methacrylates such as 2,2,2-trifluoroethyl; and other maleic esters such as ethyl maleate, propyl maleate, butyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, and the like; fumaric acid Fumaric esters such as ethyl, butyl fumarate and dibutyl fumarate; and itaconic esters such as ethyl itaconate, diethyl itaconate and butyl itaconate.
[0030]
The treated wax of the present invention can use a styrene-based monomer or an unsaturated carboxylic acid-based monomer to treat a hydrocarbon wax according to a usual method and conditions. Specifically, for example, a method using radiation, a method using a radical catalyst, and the like can be used, but a method using a radical catalyst is preferable.
[0031]
Examples of the radical catalyst include organic peroxides, organic peresters such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxidebenzoate) hexyne-3. 1,4-bis (tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert-butylperacetate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3,2,5-dimethyl -2,5-di (tert-butylperoxy) hexane, tert-butylperbenzoate, tert-butylperphenylacetate, tert-butylperisobutyrate, tert-butylper-sec-octoate, ter - butyl perpivalate, cumyl perpivalate and tert- butyl hydroperoxide diethyl acetate; other azo compounds such as azobisisobutyronitrile, and the like dimethyl azoisobutyrate. Among them, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (tert-butyl) Dialkyl peroxides such as butylperoxy) hexane and 1,4-bis (tert-butylperoxyisopropyl) benzene are preferred.
[0032]
As for the selection of monomers, two or more styrene monomers are used when treated with a styrene monomer alone, and two or more styrene monomers are used when treated with a styrene monomer and an unsaturated carboxylic acid monomer. A selection method of selecting two or more kinds of system monomers may be used, and there is no limitation on the number of selected monomers. The order in which the monomers are treated is not limited. For example, a method in which a styrene monomer and an unsaturated carboxylic acid monomer are simultaneously treated with paraffin, a method in which the styrene monomer is treated, and then the unsaturated carboxylic acid monomer is treated and so on.
[0033]
The treated wax used in the present invention is treated with a styrene-based monomer alone or a styrene-based monomer and an unsaturated carboxylic acid-based monomer. ing. The peak (1) on the high molecular side is the peak of the modified wax modified with the monomer, and the peak (2) on the low molecular side is the peak of the slightly modified or unmodified wax. The unmodified wax is preferably present also from the viewpoint of fixability. The peak area of (1) and the peak area of (2) are calculated by the following formula.
0.2 ≦ (2) / ((1) + (2)) ≦ 0.8 (Equation 1)
Is preferable, but more preferably 0.2 ≦ (2) / ((1) + (2)) <0.5.
[0034]
If (2) / ((1) + (2)) is larger than 0.8, the compatibility between the wax and the binder resin becomes low, so that free wax is easily generated, which is disadvantageous in developing property and durability. become. If (2) / ((1) + (2)) is smaller than 0.2, the dispersion of the wax in the toner becomes very good, but on the contrary, the exudation of the wax during fixing becomes disadvantageous. And the fixing temperature range becomes smaller.
[0035]
The peak areas of (1) and (2) were divided by a line drawn vertically on the horizontal axis from the inflection point of the GPC molecular weight distribution curve as shown in FIG. The area on the side was defined as (2).
[0036]
Further, the number average molecular weight (Mn {1}) of (1) was 8,000 or less and the number average molecular weight (Mn (2)) of (2) was determined by GPC molecular weight measurement of the THF-soluble portion of the treated wax of the present invention. It is preferable to satisfy 200 or more. If Mn (1) is larger than 8,000, the releasability of the modified wax is lost and the fixing temperature range is narrowed. If Mn (2) is smaller than 200, the high-temperature offset resistance and toner storage stability during fixing deteriorate.
[0037]
Furthermore, the following formula
1,000 ≦ (Mn (1) −Mn (2)) ≦ 6,000 (Formula 2)
It is desirable that
[0038]
Here, (Mn (1) -Mn (2)) represents the approximate number average molecular weight of the portion of the wax modified with the modified wax monomer. If (Mn {1}-Mn <2>) is less than 1,000, the molecular weight of the polymer portion is too small, and the storage stability becomes poor when the toner is formed. If (Mn {1}-Mn <2>) exceeds 6,000, the molecular weight of the copolymer portion is too large, so that the wax exudes during fixing and the effect as a release agent is lost.
[0039]
Further, the treated wax of the present invention has a Mn (2) of the following formula determined by GPC molecular weight measurement of the THF-soluble component.
200 ≦ Mn <2> <2000
And the amount of the wax component modified by the monomer among the wax components having a molecular weight of Mn (2) in the measurement of the molecular weight of THF-soluble component of the treated wax by GPC was A, Assuming that the amount of the wax component is B,
0.08 ≦ {B / (A + B)} × {2} / (1) +2) ▲ 0.78
Is preferably satisfied,
0.1 ≦ {B / (A + B)} × {2} / (1) +2)｝ 0.78
Is more preferably satisfied.
[0040]
Here, the values of A and B are defined as "1" 'for the high molecular weight peak and "2"' for the low molecular weight peak when the GPC curve of the treated wax is separated into two waveforms by Gaussian distribution approximation. , (1) 'and (2)' were designated as A, and the area of (2) 'was designated as B.
[0041]
Generally, from the viewpoint of low-temperature fixability, it is advantageous to lower the molecular weight and the softening point. In the present invention, the molecular weight of the untreated wax is set to 200 ≦ Mn <2> <2000. preferable. However, at this time, if {B / (A + B)} × {2} / (1) +2) is greater than 0.78, the overlapping portion A of (1) 'and (2)' will be There is very little, which means that the treated wax consists of pure unmodified wax and almost completely modified wax. When Mn {2} becomes as low as 2000 or less, unmodified wax is very soft and has a strong self-aggregating property, so that the dispersion in the binder resin tends to be further deteriorated. On the other hand, since the modified wax has a very high compatibility with the binder resin, the compatibility with the unmodified wax relatively decreases, and the modified wax is used as a compatibilizer or dispersant for the unmodified wax. It cannot function, resulting in detachment of the unmodified wax. On the other hand, when {B / (A + B)} × {(2) / ((1) + (2))} is smaller than 0.08, the unmodified wax does not desorb, but the proportion of the copolymer portion is reduced. When the toner is fixed, the exudation of the wax becomes worse, which is disadvantageous for low-temperature fixability.
[0042]
The treated wax of the present invention is obtained in one step by treating a hydrocarbon wax with a monomer, and contains a wax component having various degrees of modification and an unmodified wax component. Therefore, even when a low-molecular weight wax is used for low-temperature fixability, the unmodified wax component does not desorb and the like, and high compatibility with the binder resin component is maintained and uniformly dispersed. It is thought that it is possible.
[0043]
The treated wax of the present invention preferably has a total of 5 to 100 parts by mass of the monomer to be treated with respect to 100 parts by mass of the hydrocarbon wax. If the total amount of the monomers is less than 5 parts by mass, the effect as a treated wax cannot be obtained, and it is disadvantageous for wax fusion of a cleaning blade or a photoreceptor, a reduction in a rising speed of electrification, poor electrification, sleeve, carrier contamination, and the like. become. If the total amount of the monomers is at least 100 parts by mass, the rate of exuding the wax at the time of fixing the treated wax will decrease, and the fixing property will be disadvantageous.
[0044]
When a styrene-based monomer and an unsaturated carboxylic acid-based monomer are used in combination, (parts by mass of styrene-based monomer / parts by mass of unsaturated carboxylic-acid-based monomer) is preferably 1 to 20. If (the number of parts by mass of the styrene-based monomer / the number of parts by mass of the unsaturated carboxylic acid-based monomer) is larger than 20, the softening point of the treated wax tends to increase, so that the amount of the treated monomer is limited, which is not preferable. If (parts by mass of styrene-based monomer / parts by mass of unsaturated carboxylic acid-based monomer) is smaller than 1, the effect of compatibility with the binder resin due to the treatment of the wax is not sufficiently obtained, and the dispersibility in the toner is reduced. And charging stability becomes disadvantageous. In addition, the toner storability deteriorates.
[0045]
The release agent of the present invention preferably has a main peak temperature in a DSC endothermic curve of 45 to 120 ° C, more preferably 50 to 90 ° C. This peak value represents the softening point of the treated wax, and if the peak value is 45 ° C. or less, the storage stability of the toner is deteriorated. Further, if the peak value is 120 ° C. or higher, the low-temperature fixability of the toner is deteriorated.
[0046]
The amount of the treated wax used in the present invention is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the resin component in the toner. If the amount is less than 1 part by mass, the effect of the treated wax as a release agent is lost, and the temperature range of fixing decreases. If the amount exceeds 30 parts by mass, the toner itself softens, and the durability becomes disadvantageous.
[0047]
The DSC measurement is performed using, for example, DSC-7 manufactured by PerkinElmer. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of the calorific value uses the heat of fusion of indium.
[0048]
A measurement sample is accurately weighed in an amount of 2 to 10 mg, preferably 5 mg. This is put in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rising rate of 10 ° C./min under normal temperature and normal humidity within a measurement temperature range of 30 to 200 ° C. In this heating process, an endothermic peak of the main peak of the DSC curve in the temperature range of 30 to 200 ° C. is obtained.
[0049]
The average circularity of the toner of the present invention is 0.970 or more. When the average circularity of the toner is 0.970 or more, the toner forms uniform and thin spikes in the developing section, and it is possible to perform development faithful to a latent image, and an improvement in image quality can be expected.
[0050]
Further, since such a toner has a relatively uniform toner shape, it is easy to uniformly charge the toner, which is effective in suppressing sleeve ghost.
[0051]
When the average circularity is 0.970 or more, the transferability of the toner becomes very good. This is thought to be because the contact area between the toner particles and the photoreceptor is small, and the adhesion of the toner particles to the photoreceptor due to the mirroring power, van der Waals force, and the like is reduced.
[0052]
Further, in the circularity distribution of the toner, when the mode circularity is 0.99 or more, it means that many of the toner particles have a shape close to a true sphere, and the above-described action becomes more remarkable. preferable.
[0053]
In such a toner having a nearly spherical shape, the entire surface of the toner particles may come into contact with the surface of the toner carrier or the surface of the photoreceptor. However, the dispersion state in the toner is controlled by using the treated wax of the present invention. As a result, the durability can be further improved, and high developability can be maintained even during long-term use.
[0054]
The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of particles, and the present invention uses a flow particle image analyzer “FPIA-1000” manufactured by Toa Medical Electronics. The measurement was performed, and the circularity (Ci) of each particle measured for the particle group having a circle equivalent diameter of 3 μm or more was determined by the following equation (5), and all the particles measured as shown by the following equation (6) Is defined as the average circularity (C) obtained by dividing the sum of the circularities by the total number of particles (m).
[0055]
(Equation 1)

[0056]
In addition, the mode circularity is obtained by dividing the circularity from 0.40 to 1.00 into 61 by 0.01, and allocating the measured circularity to each divided range according to each circularity. This is the circularity of the peak having the maximum frequency value in the frequency distribution.
[0057]
In addition, "FPIA-1000" which is a measuring device used in the present invention calculates the circularity of each particle, and then calculates the average circularity and the mode circularity. A calculation method is used in which 0.40 to 1.00 are divided into 61 classes, and the average circularity and the mode circularity are calculated using the center value and frequency of the divided stores. However, an error between each value of the average circularity and the mode circularity calculated by this calculation method and each value of the average circularity and the mode 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, for the reasons of data handling such as shortening of calculation time and simplification of calculation operation formula, each particle described above is used. Such a calculation method partially modified using the concept of a calculation formula using the circularity directly may be used.
[0058]
The measurement procedure is as follows.
[0059]
About 5 mg of the toner is dispersed in 10 ml of water in which about 0.1 mg of a surfactant is dissolved to prepare a dispersion, and the dispersion is irradiated with ultrasonic waves (20 kHz, 50 W) for 5 minutes so that the concentration of the dispersion is 5,000. The average circularity and modal circularity of a particle group having a circle equivalent diameter of 3 μm or more are determined by setting the particle size to 〜20,000 / μl.
[0060]
The average circularity in the present invention is an index of the degree of unevenness of the toner, and indicates 1.000 when the toner has a perfect spherical shape. The average circularity becomes smaller as the surface shape of the toner becomes more complicated.
[0061]
In this measurement, the reason why the circularity is measured only for the particles having a circle equivalent diameter of 3 μm or more is that the particles of the external additive which are present independently of the toner particles are included in the particles having a circle equivalent diameter of less than 3 μm. This is because, due to its influence, the circularity of the toner particle group cannot be accurately estimated.
[0062]
The toner of the present invention has a weight average particle diameter of 3 to 10 μm, and more preferably 4 to 9 μm, in order to faithfully reproduce finer latent image dots for higher image quality. In the case of a toner having a weight average particle diameter of less than 3 μm, transfer residual toner on the photoreceptor increases due to a decrease in transfer efficiency, and it becomes difficult to suppress scraping of the photoreceptor and fusion of the toner in the contact charging step. Furthermore, in addition to the increase in the surface area of the entire toner, the fluidity and agitation properties of the powder are reduced, and it becomes difficult to uniformly charge the individual toner particles. A sleeve ghost is also likely to occur, which is not preferable.
[0063]
On the other hand, when the weight average particle size of the toner exceeds 10 μm, scattering is likely to occur in characters and line images, and it is difficult to obtain high resolution. Further, as the resolution of the apparatus becomes higher, the reproduction of one dot tends to be deteriorated for toner of 10 μm or more.
[0064]
It is important that the ratio of weight average particle diameter / number average particle diameter of the toner of the present invention is 1.40 or less, more preferably 1.35 or less.
[0065]
When the ratio of weight average particle diameter / number average particle diameter is larger than 1.40, it means that the particle size distribution of the toner is wide, and the selective development is likely to occur.
[0066]
Here, the average particle size and the particle size distribution of the toner can be measured by various methods such as Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter). In the present invention, Coulter Multisizer (manufactured by Coulter) is used. And an interface (manufactured by Nikkaki) for outputting a number distribution and a volume distribution and a PC9801 personal computer (manufactured by NEC) are connected, and a 1% aqueous NaCl solution is prepared using primary grade sodium chloride as an electrolytic solution. For example, ISOTON @ R-II (manufactured by Coulter Scientific Japan) can be used.
[0067]
As a measuring method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electric field aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and the number of toner particles of 2 μm or more were measured by using a 100 μm aperture as an aperture by a Coulter Multisizer in the previous period. The distribution and the number distribution are calculated. Then, a volume-based weight average particle diameter (D4) obtained from the volume distribution and a number-based length average particle diameter obtained from the number distribution, that is, a number average particle diameter (D1) are obtained. The same measurement was performed in the examples described later.
[0068]
Although the toner of the present invention contains a release agent, the dispersion state of the release agent also affects the developability as described above. For this reason, when the toner of the present invention is divided into a toner (F) having a smaller weight average particle size than the toner and a toner (G) having a larger weight average particle size, the differential thermal analysis Assuming that the heat absorption amounts of the toners (F) and (G) in the (DSC) measurement are Hf and Hg, respectively, it is preferable that 0.60 <Hg / Hf <1.50, and 0.80 <Hg / Hf <1. .20 is more preferable. Here, as Hg / Hf approaches 1, it means that the dispersibility of the release agent is better, and such a toner can be obtained by adding the treated wax in the present invention.
[0069]
A toner having a Hg / Hf of less than 0.60 has a large uneven distribution of the release agent, which means that particles containing a very large amount of the release agent are present. Such particles are liable to impair the uniformity of charging due to bleeding of the release agent onto the toner surface, and are likely to cause ghosting. Further, such a toner is not preferable because the toner tends to deteriorate in a long-term use.
[0070]
Also, it is generally known that when a release agent is contained, the chargeability of the toner is reduced, and a toner having a small particle size tends to be charged up. For this reason, if Hg / Hf is greater than 1.50, that is, if a large particle size toner contains a large amount of a release agent, the toner as a whole cannot have uniform charging properties, and ghosts may occur. It is easy to occur.
[0071]
Furthermore, an Hg / Hf greater than 1.50 may mean that a relatively large free release agent is present, and the presence of such a free release agent only adversely affects development. In this case, too, the sleeve ghost is deteriorated and the fog is increased, which is not preferable.
[0072]
By setting 0.60 <Hg / Hf <1.50 as described above, it is possible to obtain uniform chargeability even in long-term use, and it is possible to obtain a high-definition image without ghost. I have.
[0073]
As described above, the selective development property is suppressed by setting the particle size distribution to a specific value, and the synergistic effect of charging uniformity by setting the dispersibility of the release agent and the toner shape to a specific value reduces the humidity. Even under an environment, sleeve ghost can be suppressed and a uniform halftone image can be obtained.
[0074]
A charge control agent may be added to the toner of the present invention in order to stabilize the charge characteristics. As the charge control agent, a known charge control agent can be used. In particular, a charge control agent having a high charging speed and capable of stably maintaining a constant charge amount is preferable. Further, when the toner is produced by a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially having no soluble matter in an aqueous dispersion medium is particularly preferable. Specific compounds include salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphthoic acid, metal compounds of aromatic carboxylic acids such as dicarboxylic acids, metal salts or metal complexes of azo dyes or azo pigments, and sulfones as negative charge control agents. Examples thereof include a high molecular compound having an acid or carboxylic acid group in a side chain, a boron compound, a urea compound, a silicon compound, and calixarene. 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, a nigrosine compound, and an imidazole compound.
[0075]
As a method of incorporating the charge control agent into the toner, there are a method of adding the charge control agent inside the toner particles and a method of externally adding the charge control agent. The amount of use of these charge control agents is determined by the type of the binder resin, the presence or absence of other additives, the toner manufacturing method including the dispersion method, and is not limited uniquely, When added internally, it is preferably used in an amount of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the binder resin. When added externally, the amount is preferably 0.005 to 1.0 part by mass, more preferably 0.01 to 0.3 part by mass, based on 100 parts by mass of the toner.
[0076]
However, the toner of the present invention does not necessarily require the addition of a charge control agent, and the toner necessarily includes the charge control agent by positively utilizing frictional charging between the toner layer pressure regulating member and the toner carrier. There is no.
[0077]
The toner of the present invention may be prepared by preparing toners having different particle sizes, colorants, and release agent contents, and then mixing the toners, and a method of making the dispersion of the colorant and the release agent different in the production stage. Is not particularly limited. However, generally, toner particles obtained by a pulverization method are irregular in shape, and in order to obtain physical properties such as an average circularity of 0.970 or more, which is an essential condition of the toner according to the present invention, mechanical and thermal properties are required. It is necessary to perform a target or some special processing, resulting in poor productivity. Therefore, the toner of the present invention is preferably produced in water by a dispersion polymerization method, an association aggregation method, a suspension polymerization method, or the like. Further, after the binder resin, a coloring agent, a release agent, and other additives are mixed in an organic solvent in which the binder resin is soluble to adjust the oil component, the oil component is suspended in an aqueous medium. It is also one of the preferred embodiments to produce the toner of the present invention by preparing a suspension by making the suspension into particles and removing the organic solvent from the suspension. Among them, the suspension polymerization method is particularly preferable because various essential properties of the present invention can be easily obtained.
[0078]
The suspension polymerization method is a method of uniformly dissolving or dispersing a polymerizable monomer and a colorant (further, if necessary, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives) into a polymerizable monomer system. After that, the polymerizable monomer system is dispersed in a continuous layer (for example, an aqueous phase) containing a dispersion stabilizer by using a suitable stirrer, and simultaneously undergoes a polymerization reaction to obtain a toner having a desired particle size. What you get. The toner obtained by the suspension polymerization method (hereinafter referred to as “polymerized toner”) is suitable for the present invention having an average circularity of 0.970 or more and a mode circularity of 099 or more since the individual toner particles have a substantially spherical shape. It is easy to obtain a toner that satisfies various physical properties, and furthermore, such a toner has a relatively uniform distribution of the charge amount, and thus has high transferability.
[0079]
In the production of the polymerized toner according to the present invention, the polymerizable monomers constituting the polymerizable monomer system include the following.
[0080]
Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-ethylstyrene; methyl acrylate, ethyl acrylate, Acrylic esters such as n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate Class; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, Methacrylic acid dimethyl aminoethyl, methacrylic acid esters such as diethylaminoethyl methacrylate; and other acrylonitrile, methacrylonitrile, and the like monomers acrylamide. These monomers can be used alone or as a mixture. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in a mixture with another monomer from the viewpoint of the developing property and durability of the toner.
[0081]
In the production of the polymerized toner according to the present invention, polymerization may be performed by adding a resin to the polymerizable monomer system. For example, hydrophilic functional groups such as amino groups, carboxylic acid groups, hydroxyl groups, sulfonic acid groups, glycidyl groups, and nitrile groups, which cannot be used because monomers dissolve in aqueous suspensions and cause emulsion polymerization due to water solubility. When it is desired to introduce the contained polymerizable monomer components into the toner, they are formed into a copolymer, such as a random copolymer, a block copolymer, or a graft copolymer of these and a vinyl compound such as styrene or ethylene. Or polycondensates such as polyesters and polyamides, and polyaddition polymers such as polyethers and polyimines. When such a high molecular polymer containing a polar functional group is coexisted in the toner, the above-mentioned wax component is phase-separated, the encapsulation becomes stronger, and a toner having good blocking resistance and developability can be obtained.
[0082]
By containing a polyester resin among these resins, the effect becomes great. This is for the following reason. Since the polyester resin contains many ester bonds, which are relatively polar functional groups, the polarity of the resin itself increases. Due to its polarity, the polyester tends to be unevenly distributed on the surface of the liquid droplets in the aqueous dispersion medium, and the polymerization proceeds while maintaining the state, thereby forming a toner. For this reason, the uneven distribution of the polyester resin on the toner surface makes the surface state and surface composition uniform, and as a result, the chargeability is uniform and the encapsulating property of the release agent is good. With this, very good developability can be obtained.
[0083]
Further, a resin other than the above may be added to the monomer system for the purpose of improving the dispersibility or fixing property of the material, or the image characteristics, and the resin used is, for example, styrene such as polystyrene or polyvinyl toluene. And styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene -Butyl methacrylate copolymer, styrene-dimethylamino methacrylate Copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid Styrene-based copolymers such as copolymers and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resins, polyester resins, polyamide resins, epoxy resins , Polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin and the like can be used alone or in combination. The addition amount of these resins is preferably 1 to 20 parts by mass based on 100 parts by mass of the polymerizable monomer. If the amount is less than 1 part by mass, the effect of addition is small, while if it exceeds 20 parts by mass, it becomes difficult to design various physical properties of the polymerized toner.
[0084]
Furthermore, if a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the polymerizable monomer is dissolved in the monomer and polymerized, a toner having a wide molecular weight distribution and high offset resistance can be obtained. I can do it.
[0085]
As the colorant used in the present invention, as a black colorant, a carbon black, a magnetic substance, or a black colorant using a yellow / magenta / cyan colorant is used.
[0086]
When a magnetic material is used as the black colorant, the magnetic material is preferably subjected to a hydrophobic treatment with a coupling agent. When the surface of the magnetic substance is hydrophobized, a magnetic substance obtained by performing a surface treatment while hydrolyzing a coupling agent while dispersing the magnetic substance to have a primary particle size in an aqueous medium is preferable. The hydrophobization treatment method in an aqueous medium is less likely to cause coalescence of the magnetic particles than the treatment in the gas phase, and the repelling action between the magnetic particles by the hydrophobization process acts. Since the surface treatment is performed in a state of substantially primary particles, high uniformity of hydrophobicity is achieved, which is preferable.
[0087]
The method of treating the surface of the magnetic material while hydrolyzing the coupling agent in an aqueous medium does not require the use of a coupling agent that generates a gas such as chlorosilanes or silazanes. In the phase, the magnetic particles are easily united with each other, and a high-viscosity coupling agent, which has been difficult to treat well, can be used, and the effect of hydrophobization is enormous.
[0088]
Examples of the coupling agent that can be used in the present invention include a silane coupling agent and a titanium coupling agent. More preferably used is a silane coupling agent, having the general formula
RmSiYn
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group, a methacryl group, and n represents an integer of 1 to 3. Show. ]
It is shown by. For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethyl Examples include methoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.
[0089]
In particular, the expression
C_pH_{2p + 1}-Si- (OC_qH_{2q + 1})₃
[In the formula, p represents an integer of 2 to 20, and q represents an integer of 1 to 3.]
The magnetic material is preferably subjected to a hydrophobic treatment in an aqueous medium using an alkyltrialkoxysilane coupling agent represented by the following formula.
[0090]
If p in the above formula is smaller than 2, the hydrophobizing treatment is easy, but it is difficult to impart sufficient hydrophobicity. The coalescence between the particles increases, and it becomes difficult to sufficiently disperse the magnetic particles in the toner.
[0091]
On the other hand, when q is larger than 3, the reactivity of the silane coupling agent is reduced, and it is difficult to sufficiently perform the hydrophobic treatment. In particular, alkyltrialkoxysilane in which p represents an integer of 2 to 20 (more preferably an integer of 3 to 15) and q represents an integer of 1 to 3 (more preferably an integer of 1 or 2). It is good to use a coupling agent.
[0092]
The amount of the treatment is 0.05 to 20 parts by mass, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the magnetic substance, and the treating agent depends on the surface area of the magnetic substance, the reactivity of the coupling agent, and the like. Is preferably adjusted.
[0093]
In the present invention, the aqueous medium is a medium containing water as a main component. Specific examples of the aqueous medium include water itself, water in which a small amount of a surfactant is added, water in which a pH adjuster is added, and water in which an organic solvent is added. As the surfactant, a nonionic surfactant such as polyvinyl alcohol is preferable. The surfactant is preferably added in an amount of 0.1 to 5% by mass based on water. Examples of the pH adjuster include an inorganic acid such as hydrochloric acid.
[0094]
The stirring is sufficiently performed, for example, by a mixer having a stirring blade (specifically, a high shear mixing device such as an attritor or a TK homomixer) so that the magnetic fine particles become primary particles in an aqueous medium. Is good.
[0095]
The magnetic particles thus obtained do not show aggregation of the particles and have a uniform hydrophobic treatment on the surface. Therefore, when used as a toner material, the magnetic particles have very good dispersibility in the toner, and furthermore, the toner surface There is no exposure from.
[0096]
The magnetic material used in the toner of the present invention may contain an element such as iron, phosphorus, cobalt, nickel, copper, magnesium, manganese, aluminum, or silicon. It is mainly composed of iron, and these are used alone or in combination of two or more. These magnetic materials have a BET specific surface area of 2 to 30 m by a nitrogen adsorption method.²/ G is preferred, and especially 3 to 28 m²/ G is more preferred. Further, those having a Mohs hardness of 5 to 7 are preferable.
[0097]
The magnetic material used in the toner of the present invention is preferably used in an amount of 10 to 200 parts by mass, more preferably 20 to 180 parts by mass, based on 100 parts by mass of the polymerizable monomer. If the amount of the iron oxide is less than 10 parts by mass, the coloring power of the developer is poor, and it is difficult to suppress fog. On the other hand, if the amount exceeds 200 parts by mass, the coercive force due to the magnetic force applied to the developer carrier increases and the Not only is it difficult to uniformly disperse the magnetic material in the individual toner particles, but also the fixability is lowered.
[0098]
As a colorant when the toner of the present invention is used as a color toner, known dyes and / or pigments are used. Examples include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, sulvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, disazo yellow, and the like. Can be used alone or in combination of two or more. The amount of the colorant used is preferably about 2 to 25 parts by mass based on 100 parts by mass of the polymerizable monomer.
[0099]
As the polymerization initiator used in the production of the toner of the present invention, one having a half life of 0.5 to 30 hours during the polymerization reaction is added in an amount of 0.5 to 20 parts by mass based on 100 parts by mass of the polymerizable monomer. It is preferable to carry out the polymerization reaction with the added amount because a polymer having a maximum molecular weight between 10,000 and 100,000 can be obtained, and the desired strength and appropriate melting characteristics can be imparted to the toner.
[0100]
Examples of the polymerization initiator include conventionally known azo-based polymerization initiators and peroxide-based polymerization initiators. Examples of the azo-based polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile). , 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisiso Butyronitrile and the like are exemplified. Examples of the peroxide-based polymerization initiator include t-butyl peroxyacetate, t-butyl peroxylaurate, t-butyl peroxypivalate, and t-butyl peroxy-2-ethylhexa. Noate, t-butyl peroxyisobutyrate, t-butyl peroxy neodecanoate, t-hexyl peroxy acetate, t-hexyl peroxy Urate, t-hexylperoxypivalate, t-hexylperoxy-2-ethylhexanoate, t-hexylperoxyisobutyrate, t-hexylperoxyneodecanoate, t-butylperoxybenzoate, α , Α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1,1,3, 3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoyl peroxy) hexane, 1 -Cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexyl -Oxyisopropyl monocarbonate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane T-butylperoxy-m-toluoylbenzoate, bis (t-butylperoxy) isophthalate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, Peroxyesters such as 2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane; diacyl peroxides such as benzoyl peroxide, lauroyl peroxide and isobutyryl peroxide; diisopropylperoxydi -Carbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, such as peroxydicarbonate, 1,1-di-t-butylperoxycyclohexane, 1,1-di-t-hexylperoxycyclohexane, Peroxyketals such as 1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 2,2-di-tert-butylperoxybutane, di-tert-butyl peroxide, dicumyl peroxide; Examples thereof include dialkyl peroxides such as t-butylcumyl peroxide, t-butylperoxyallyl monocarbonate, and the like. Two or more of these initiators can be used as needed.
[0101]
When producing the toner of the present invention, a crosslinking agent may be added. The preferable addition amount of the crosslinking agent is 0.001 to 15 parts by mass based on 100 parts by mass of the polymerizable monomer.
[0102]
Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene, or the like; for example, ethylene glycol diacrylate, ethylene glycol diacrylate, or the like. Carboxylic acid esters having two double bonds such as methacrylate and 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and having three or more vinyl groups Compound alone or as a mixture.
[0103]
In the method for producing the toner of the present invention by a polymerization method, generally, the above-mentioned toner composition and the like are appropriately added, and the polymerizable material is uniformly dissolved or dispersed by a disperser such as a homogenizer, a ball mill, a colloid mill, and an ultrasonic disperser. The monomer system is suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to quickly obtain the desired toner particle size. As for the timing of the addition of the polymerization initiator, the polymerization initiator may be added at the same time as the other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Immediately after granulation and before initiating the polymerization reaction, a polymerization initiator dissolved in a polymerizable monomer or a solvent can be added.
[0104]
After the granulation, stirring may be performed using a normal stirrer to such an extent that the particle state is maintained and the floating and settling of the particles are prevented.
[0105]
When producing the toner of the present invention, a known surfactant, organic dispersant, or inorganic dispersant can be used as a dispersion stabilizer. Above all, inorganic dispersants are unlikely to produce harmful ultrafine powders, and because of their steric hindrance, have obtained dispersion stability, so that they do not easily lose stability even when the reaction temperature is changed, are easy to wash, and do not adversely affect the toner. Therefore, it can be preferably used. Examples of such inorganic dispersants include polyphosphate metal salts such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate, carbonates such as calcium carbonate and magnesium carbonate, calcium metasilicate, calcium sulfate and barium sulfate. Examples thereof include inorganic salts, inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite, and alumina.
[0106]
When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated and used in an aqueous medium. For example, in the case of calcium phosphate, a water-insoluble calcium phosphate can be produced by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring, and more uniform and fine dispersion can be achieved. At this time, a water-soluble sodium chloride salt is simultaneously produced as a by-product, but if the water-soluble salt is present in the aqueous medium, the dissolution of the polymerizable monomer in water is suppressed, and the ultrafine toner due to emulsion polymerization is formed. This is more convenient because it hardly occurs. Since it becomes an obstacle when removing the residual polymerizable monomer at the end of the polymerization reaction, it is better to replace the aqueous medium or desalinate with an ion exchange resin. The inorganic dispersant can be almost completely removed by dissolving with an acid or alkali after completion of the polymerization.
[0107]
It is preferable that these inorganic dispersants are used alone in an amount of 0.2 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. Since it is somewhat weak, a surfactant of 0.001 to 0.1 parts by mass may be used in combination.
[0108]
Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.
[0109]
In the polymerization step, the polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. When the polymerization is carried out in this temperature range, the release agent and waxes to be sealed inside are precipitated by phase separation, and the encapsulation becomes more complete. In order to consume the remaining polymerizable monomer, it is possible to raise the reaction temperature to 90 to 150 ° C. at the end of the polymerization reaction.
[0110]
After completion of the polymerization, the polymerized toner particles are filtered, washed, and dried by a known method, and if necessary, an inorganic fine powder is mixed and adhered to the surface to obtain the toner of the present invention. It is also possible to insert a classification step into the manufacturing process to cut coarse or fine powder.
[0111]
To improve the image quality, it is preferable that a fluidity improver is externally added to the toner particles of the present invention.
[0112]
As the fluidity improver, inorganic fine powder such as silicic acid fine powder, titanium oxide, and aluminum oxide are preferable. The inorganic fine powder is preferably hydrophobized with a hydrophobizing agent such as a silane coupling agent, silicone oil or a mixture thereof.
[0113]
When the toner particles are nonmagnetic color toner particles for full-color image formation, it is preferable to use titanium oxide fine particles as an external additive.
[0114]
The flow improver is generally used in an amount of 0.1 to 5 parts by mass based on 100 parts by mass of the toner particles.
[0115]
It is preferable to use a mixer such as a Henschel mixer for mixing the toner particles and the external additive.
[0116]
When the toner of the present invention is used for a two-component developer, the toner is used by being mixed with a magnetic carrier. As the magnetic carrier, for example, metal particles such as iron, nickel, copper, zinc, cobalt, manganese, chromium, and rare earths whose surface is oxidized or not oxidized, alloy particles thereof, oxide particles, and ferrite can be used.
[0117]
The coated carrier in which the surface of the magnetic carrier particles is coated with a resin is particularly preferable in a developing method in which an AC bias is applied to a developing sleeve. As a coating method, a method of dissolving or suspending a coating material such as a resin in a solvent to adhere a coating solution prepared to the surface of the magnetic carrier core particles, and a method of mixing the magnetic carrier core particles and the coating material with a powder For example, a conventionally known method can be applied.
[0118]
Examples of a coating material on the surface of the magnetic carrier core particles include silicone resin, polyester resin, styrene resin, acrylic resin, polyamide, polyvinyl butyral, and amino acrylate resin. These may be used alone or in combination.
[0119]
When a two-component developer is prepared by mixing the toner of the present invention and a magnetic carrier, the mixing ratio is usually 2 to 15% by mass, preferably 4 to 13% by mass as the toner concentration in the developer. Good results are obtained. If the toner concentration is less than 2% by mass, the image density tends to decrease.
[0120]
Next, an example of an image forming apparatus in which the toner of the present invention can be preferably used will be specifically described with reference to the drawings.
[0121]
A laser beam printer of 600 dpi (manufactured by Canon: LBP-8Mark @ IV) as shown in FIG. 3 was prepared as an image forming apparatus. This device has been modified so that the process speed is 80 mm / s. As shown in FIG. 3, this device uniformly charges a photoconductor 56 using a charging roller 51 to which DC and AC components are applied. At this time, the DC component is controlled to a constant voltage, and the AC component is controlled to a constant current. The conductive layer of the charging roller has a volume efficiency of 10%.²Ω · cm, resistance layer is 10⁷Ω · cm, and the contact pressure was set to 230 N / m. After charging, an image portion is exposed by a laser beam 60 to form an electrostatic latent image, and a toner image is formed as a visible image using a one-component non-magnetic toner. 5 × 10⁹Ω · cm) 57 to transfer the toner image to the transfer material 58. The transfer material bearing the toner image is fixed on the transfer material by the fixing device 63. The contact pressure between the photosensitive member and the transfer roller was set to a linear pressure of 130 N / m. Further, the toner partially left on the photoreceptor is cleaned by a cleaning member 59 made of urethane rubber.
[0122]
As shown in FIG. 3, in the developing container 52, a toner carrier 54 as a toner supply body is in contact with a photoreceptor 56. The moving direction and the rotational peripheral speed of the surface of the toner carrier 54 are the same in the contact portion with the surface of the photosensitive drum.
[0123]
As a means for applying the toner to the toner carrier, an application roller 55 is provided at a developing portion, and is in contact with the toner carrier. At the contact portion, the toner is applied onto the toner carrier by rotating the application roller 55 such that the surface of the application roller 55 moves in a direction opposite to the moving direction of the toner carrier. Further, a resin-coated stainless steel blade 53 is attached to control the coat layer of the toner on the toner carrier. In the developing area, a DC developing bias is applied between the photoconductor 56 and the toner carrier 54, and the toner on the toner carrier flies on the photoconductor 56 according to the electrostatic latent image to become a visible image. .
[0124]
Next, an example of an image forming method for forming a full-color image will be described with reference to the drawings.
[0125]
FIG. 4 shows an image forming apparatus in which a toner image of each color is formed by a plurality of image forming units, and the toner images are successively superimposed and transferred on the same transfer material. Here, the first, second, third, and fourth image forming units 29_a, 29_b, 29_c, 29_dEach image forming unit is provided with a dedicated electrostatic latent image holder, a so-called photosensitive drum 19._a, 19_b, 19_c, And 19_dIs provided. Photosensitive drum 19_aTo 19_dIs a latent image forming means 23_a, 23_b, 23_cAnd 23_d, Developing unit 17_a, 17_b, 17_cAnd 17_d, Transfer discharger 24_a, 24_b, 24_cAnd 24_dAnd cleaning section 18_a, 18_b, 18_cAnd 18_dIs arranged. With such a configuration, first, the first image forming unit 29_aPhotosensitive drum 19_aLatent image forming means 23 on top_aThereby, a latent image of, for example, a yellow component color in the document image is formed. The latent image is developed by developing means 17._aIs made visible with a developer having a yellow toner of_aIs transferred to a recording material S as a transfer material. While the yellow image is being transferred to the transfer material S as described above, the second image forming unit 29_bThen, the latent image of the magenta component color is_bAnd developing means 17_bIs made visible with a developer having magenta toner. This visible image (magenta toner image) is used for the first image forming unit 29 described above._aTransfer material S after the transfer at_bIs transferred onto the transfer material S at a predetermined position. Hereinafter, the third and fourth image forming units 29 are formed in the same manner as described above._c, 29_dThus, cyan and black images are formed, and the cyan and black colors are transferred onto the same transfer material S in a superimposed manner. When such an image forming process is completed, the transfer material S is conveyed to the fixing unit 22, where the image on the transfer material S is fixed. Thus, a multicolor image is obtained on the transfer material S. Each sightseeing drum 19 whose transfer has been completed_a, 19_b, 19_cAnd 19_dIs the cleaning unit 18_a, 18_b, 18_cAnd 18_dRemoves the residual toner, and is provided for the subsequent latent image formation. In the image forming apparatus, the transport belt 25 is used for transporting the recording material S as the transfer material. In FIG. 4, the transfer material S is transported from right to left. Image forming unit 29_a, 29_b, 29_cAnd 29_dEach transfer part 24 in_a, 24_b, 24_cAnd 24_dAnd undergoes transcription. In this image forming method, a transport belt using a mesh of tetron fiber as a transport means for transporting the transfer material and a thin dielectric such as polyethylene terephthalate resin, polyimide resin and urethane resin from the viewpoint of ease of processing and durability. A conveyor belt using a body sheet is used. When the transfer material S is the fourth image forming unit 29^d, The AC voltage is applied to the static eliminator 20, the transfer material S is neutralized, separated from the belt 25, and then enters the fixing device 22, where the image is fixed, and is discharged from the discharge port 26.
[0126]
In this image forming method, the image forming units are provided with independent electrostatic latent image holders, and the transfer material is sequentially transferred to the transfer unit of each electrostatic latent image holder by a belt-type conveying unit. You may be comprised so that it may be sent to. Further, in this image forming method, an electrostatic latent image holding member common to the image forming portion is provided, and the transfer material is repeatedly fed to the transfer portion of the electrostatic latent image holding member by a drum type conveying means. Then, it may be configured to receive the transfer of each color.
[0127]
Next, an example of an image forming apparatus that can suitably use a magnetic toner using a magnetic material as a colorant will be specifically described with reference to the drawings.
[0128]
In FIG. 5, reference numeral 1 denotes a photosensitive drum, around which a primary charging roller 5, a developing device 10, a transfer charging roller 3, a cleaner 4, a paper feed roller 7, and the like are provided. Then, the photosensitive drum 1 is charged to -700 V by the primary charging roller 5 (applied voltage is AC voltage -2.0 kVpp, DC voltage -700 VDC). The photosensitive drum 1 is exposed by irradiating the photosensitive drum 1 with a laser beam 12 by a laser generator 6. The electrostatic latent image on the photosensitive drum 1 is developed with a one-component magnetic toner by a developing device 10 and is transferred onto a transfer material by a transfer charging roller 3 which is in contact with the photosensitive drum 1 via the transfer material. The transfer material bearing the toner image is carried to a fixing device 9 by a conveyor belt 8 or the like, and is fixed on the transfer material. Further, the toner partially left on the photosensitive drum 1 is cleaned by the cleaner 4. As shown in FIG. 5, the developing device 10 is provided with a cylindrical toner carrier 2 (hereinafter referred to as a developing sleeve) made of a non-magnetic metal such as aluminum or stainless steel, in the vicinity of the photosensitive drum 1. The gap between the photosensitive drum 1 and the developing sleeve 2 is maintained at about 230 μm by a sleeve / photosensitive body gap holding member (not shown). Inside the developing sleeve, a magnet roller (not shown) is fixed and disposed concentrically with the developing sleeve 2. However, the developing sleeve 2 is rotatable. The magnet roller is provided with a plurality of magnetic poles, which affect development, toner coating amount regulation, toner intake / conveyance, and prevention of toner blowing. An elastic blade 13 is provided as a member for regulating the amount of magnetic toner adhered to and conveyed to the developing sleeve 2, and the amount of toner conveyed to the developing area is controlled by the contact pressure of the elastic blade 13 against the developing sleeve 2. . In the developing area, a DC and AC developing bias is applied between the photosensitive drum 1 and the developing sleeve 2, and the toner on the developing sleeve 2 flies on the photosensitive drum 1 according to the electrostatic latent image to form a visible image. It becomes.
[0129]
・ DSC measurement
It measures as follows using a differential scanning calorimeter (DSC measuring device) and DSC-7 (made by Perkin Elmer).
[0130]
A measurement sample is accurately weighed in an amount of 2 to 10 mg, preferably 5 mg. This is put in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rising rate of 10 ° C./min under normal temperature and normal humidity within a measurement temperature range of 30 to 200 ° C. In this heating process, an endothermic peak of the main peak of the DSC curve in the temperature range of 30 to 200 ° C. is obtained.
[0131]
・ GPC measurement
The molecular weight of a chromatogram by gel permeation chromatography (GPC) is measured under the following conditions.
[0132]
The column was stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) was passed through the column at this temperature as a solvent at a flow rate of 1 ml per minute, and the resin was adjusted to a sample concentration of 0.05 to 0.6% by mass. The measurement is performed by injecting about 50 to 200 μl of a THF sample solution. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number (retention time). As a standard polystyrene sample for preparing a calibration curve, for example, Tosoh Corporation or Pressure Chemical Co. Has a molecular weight of 6 × 10², 2.1 × 10³, 4 × 10³, 1.75 × 10⁴, 5.1 × 10⁴, 1.1 × 10⁵3.9 × 10⁵, 8.6 × 10⁵, 2 × 10⁶, 4.48 × 10⁶It is appropriate to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.
[0133]
As a column, 10³~ 2 × 10⁶In order to accurately measure the molecular weight region of, it is preferable to combine a plurality of commercially available polystyrene gel columns, for example, a combination of Showex DPC's Shodex @ GPC @ KF-801, 802, 803, 804, 805, 806, 807 or Waters, μ-styragel 500, 10³, 10⁴, 10⁵Can be cited.
[0134]
【Example】
Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples. Parts in the following formulations are parts by mass.
[0135]
(Production method of treated wax)
After adding 80 g of dicumyl peroxide as a reaction initiator to 520 g of styrene monomer and 120 g of normal butyl acrylate, the mixture was dropped into 3280 g of heated and melted paraffin wax A with stirring, and reacted for 4 hours. Got.
[0136]
The type of wax, the ratio of the styrene monomer, the type and ratio of the unsaturated carboxylic acid monomer, the heating temperature, and the like were changed to similarly obtain a treated wax. Tables 1 and 2 show the ratios and characteristics.
[0137]
[Table 1]

[0138]
[Table 2]

[0139]
(Production method of hydrophobic magnetic iron oxide)
An aqueous solution containing ferrous hydroxide was prepared by mixing 1.0 to 1.1 equivalents of a caustic soda solution with respect to iron ions in the aqueous ferrous sulfate solution. While maintaining the pH of the aqueous solution at 8, the air was blown therein to perform an oxidation reaction at 80 to 90 ° C. to prepare a slurry liquid for generating seed crystals. Next, an aqueous ferrous sulfate solution was added to this slurry liquid so as to be 0.9 to 1.2 equivalents to the initial alkali amount (sodium component of caustic soda), and then the slurry liquid was maintained at pH = 8. The oxidation reaction was allowed to proceed while blowing air, and the pH was adjusted to about 6 at the end of the oxidation reaction to terminate the oxidation reaction. The produced iron oxide particles are washed, filtered, taken out once, and re-dispersed in another water without drying. Then, the pH of the re-dispersed liquid is adjusted, and the silane coupling agent [n-C₁₀H₂₁Si (OCH₃)₃] Was added to 100 parts of magnetic iron oxide, and the mixture was sufficiently stirred. The formed hydrophobic iron oxide particles were washed, filtered, and dried by a conventional method, and then the aggregated particles were crushed to obtain a hydrophobic magnetic iron oxide.
[0140]
(Toner manufacturing method)
Production of Toner 1
0.1 M Na in 720 parts of ion exchange water₃PO₄After adding 450 parts of an aqueous solution and 19 parts of 1N hydrochloric acid and heating to 60 ° C., 1.0 M CaCl 2 was added.₂67.7 parts of an aqueous solution was added to obtain an aqueous medium containing a dispersion stabilizer and having a pH of 5.3.
[0141]
Styrene 78 parts
n-butyl acrylate @ 22 parts
Divinylbenzene 0.5 part
5 parts of saturated polyester resin
Negative charge control agent (dialkyl salicylic acid aluminum complex compound) 1 part
Carbon black 10 parts
The above formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Kakoki Co., Ltd.). The monomer composition was heated to 60 ° C., and 1-10 parts of the treated wax was added, mixed and dissolved, and 4 parts by mass of a polymerization initiator t-butyl-oxy-2-ethylhexanoate was dissolved therein.
[0142]
The above polymerizable monomer system is charged into the aqueous medium,₂Under an atmosphere, the mixture was stirred at 10,000 rpm for 15 minutes with a TK homomixer (Tokiki Kagaku Kogyo Co., Ltd.) to perform granulation. Thereafter, the mixture was reacted at 80 ° C. for 8 hours while stirring with a paddle stirring blade. After completion of the reaction, the suspension was cooled, hydrochloric acid was added to dissolve the dispersant at pH = 2 or less, the dispersant was dissolved, and the mixture was filtered, washed with water and dried to obtain toner particles 1.
[0143]
After 100 parts of the toner particles and silica having a primary particle diameter of 12 nm are treated with hexamethyldisilazane and then treated with silicone oil, the BET value after the treatment is 120 m²/ G of hydrophobic silica fine powder of 1.0 g / g was mixed using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) to prepare Toner 1 having a weight average particle size of 6.9 μm.
[0144]
1,200 g of the obtained toner was subjected to air classification (Elbow Jet Classifier EJ-L-3: manufactured by Nippon Steel Mining) to obtain 98 g of the toner (F) and 101 g of the toner (G). When the endothermic amount of the release agent was measured for each of the obtained toners (F) and (G), Hg / Hf was 0.98. Table 3 shows the physical properties of Toner 1.
[0145]
Production of toners 2-4
Toners 2 to 4 were obtained in the same manner as in the production of toner 1 except that treated wax 1 was changed to treated waxes 2 to 4. Table 3 shows the physical properties of Toners 2 to 4.
[0146]
Production of toner 5
Toner 5 was obtained in the same manner as in the production of toner 1 except that treated wax 1 was changed to treated wax 6. Table 3 shows the physical properties of Toner 5.
[0147]
Production of toner 6
Toner 6 was obtained in the same manner as in the production of toner 1, except that treated wax 1 was changed to treated wax 8. Table 3 shows the physical properties of Toner 6.
[0148]
Production of toners 7 to 10
Toners 7 to 10 were obtained in the same manner as in the production of the toner 1 except that the treated wax 1 was changed to the treated waxes 11 to 14. Table 3 shows the physical properties of Toners 7 to 10.
[0149]
Production of toner 11
A toner 11 was obtained in the same manner as in the production of the toner 1, except that the amount of the treated wax 1 was changed to 0.7 part. Table 3 shows the physical properties of Toner 11.
[0150]
Production of toner 12
A toner 12 was obtained in the same manner as in the production of the toner 1, except that the amount of the treated wax 1 was changed to 31 parts. Table 3 shows the physical properties of Toner 12.
[0151]
Production of toner 13
A toner 13 was obtained in the same manner as in the production of the toner 1 except that the treated wax 1 was changed to the treated wax 5. Table 3 shows the physical properties of Toner 13.
[0152]
Production of toner 14
A toner 14 was obtained in the same manner as in the production of the toner 1 except that the treated wax 1 was changed to the treated wax 7. Table 3 shows the physical properties of Toner 14.
[0153]
Production of toners 15-16
Toners 15 to 16 were obtained in the same manner as in the production of toner 1 except that treated wax 1 was changed to treated waxes 9 to 10. Table 3 shows the physical properties of Toners 15 and 16.
[0154]
Production of toner 17
A toner 17 was obtained in the same manner as in the production of the toner 1 except that the treated wax 1 was changed to the treated wax 15. Table 3 shows the physical properties of Toner 17.
[0155]
Production of toner 18
A toner 18 was obtained in the same manner as in the production of the toner 1, except that the treated wax 1 was changed to paraffin wax A. Table 3 shows the physical properties of Toner 18.
[0156]
Production of toner 19
0.1 M Na in 720 parts of ion exchange water₃PO₄After 226 parts of the aqueous solution and 19 parts of 1N hydrochloric acid were added and heated to 60 ° C., 1.0 M CaCl 2 was added.₂Toner 19 was obtained in the same manner as in the production of Toner 1, except that 33.9 parts of an aqueous solution was added to obtain a pH = 5.3 aqueous medium containing a dispersion stabilizer. Table 3 shows the physical properties of Toner 19.
[0157]
Production of toner 20
Toner 20 was obtained in the same manner as in the production of toner 1, except that carbon black 10 parts was changed to hydrophobic magnetic iron oxide 90 parts. Table 3 shows the physical properties of Toner 20.
[0158]
Production of toner 21
Styrene / n-butyl acrylate copolymer 100 parts
(Mass ratio 78/22)
5 parts of saturated polyester resin
Negative charge control agent (monoazo dye-based Fe compound) 4 parts
Carbon black 10 parts
1 10 parts of treated wax
The above materials were mixed in a blender, melt-kneaded in a twin-screw extruder heated to 110 ° C., the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill. The pulverized product was subjected to air classification to obtain toner particles 20. To 100 parts of the toner particles 20, 1.0 part of silica used in the production of the toner 1 was mixed using a Henschel mixer to prepare a toner 21 having a weight average particle diameter of 8.4 μm. Table 3 shows the physical properties of Toner 21.
[0159]
Production of toner 22
Using a hybridizer, the toner particles 21 obtained in the production of the toner 21 were treated twice at 6000 rpm for 3 minutes to obtain toner particles 22. To 100 parts of the toner particles, 1.0 part of silica used in the production of Toner 1 was added and mixed with a Henschel mixer to prepare Toner 22. Table 3 shows the physical properties of Toner 22.
[0160]
Production of toner 23
Styrene 65 parts
2-ethylhexyl acrylate 35 parts
Divinylbenzene 0.8 parts
Carbon black 10 parts
8 parts of saturated polyester resin
2 parts of unsaturated polyester resin
The above formulation was uniformly dispersed using an attritor. Thereafter, the mixture was heated to 60 ° C., and 10 parts of the treated wax 1 used in the production of the toner 1 and 3.5 parts of 2,2′-azobisisobutyronitrile were added and dissolved.
[0161]
Then, after heating 650 parts of an aqueous colloid solution of 4% by mass of tricalcium phosphate to 60 ° C., 134.3 parts of the above polymerizable monomer system is added, and the mixture is rotated at room temperature using a TK homomixer. The emulsion was dispersed at several 10,000 rpm for 3 minutes.
[0162]
Thereafter, the mixture was reacted at 85 ° C. for 10 hours while stirring under a nitrogen atmosphere, and then cooled to room temperature to obtain a toner particle dispersion.
[0163]
Next, 13.0 parts of styrene, 7.0 parts of 2-ethylhexyl acrylate, 0.4 part of 2,2′-azobisisobutyronitrile, 0.2 part of divinylbenzene, and 0.1 part of sodium lauryl sulfate were added to water. The mixture was added to 20 parts and dispersed using an ultrasonic homogenizer to obtain 40.7 parts of a water emulsion.
[0164]
This was dropped into the toner particle dispersion to swell the particles. Thereafter, the mixture was stirred under a nitrogen atmosphere and reacted at 85 ° C. for 10 hours. Thereafter, the suspension was cooled, washed, filtered, and dried in the same manner as in the case of toner 1, and then subjected to air classification to obtain toner particles 23.
[0165]
100 parts of the toner particles 23 and 1.0 part of silica used in the production of the toner 1 were mixed using a Henschel mixer to prepare a toner 23 having a weight average particle size of 7.8 μm. Table 3 shows the physical properties of Toner 23.
[0166]
[Table 3]

[0167]
[Example 1]
As an image forming apparatus, an LBP-8 Mark IV was modified and an apparatus generally shown in FIG. 3 was used.
[0168]
The potential of the electrostatic charge image carrier was set to a dark portion potential Vd = -580 V and a bright portion potential VL = -150 V. As a toner carrier, a medium resistance rubber roller (diameter 16 mm, hardness ASKER @ C 45 degrees, resistance 10) made of silicone rubber in which resistance is adjusted by dispersing carbon black.⁵(Ω · cm). The developing contact width at this time was set to about 3 mm. The peripheral speed of the toner carrier was 150% (120 mm / sec) in the forward direction with respect to the peripheral speed of the photoconductor (80 mm / sec). An application roller made of urethane foam rubber was provided as a toner application member, and was brought into contact with the toner carrier. A voltage of about -550 V was applied to the application roller. Further, a stainless steel blade coated with a resin as a toner regulating member was brought into contact with a linear pressure of 39.2 N / m (40 g / cm). Further, the applied voltage at the time of development was only a DC component (−450 V).
[0169]
Charging The applied voltage during charging was a DC component (-1.2 kV), and the applied voltage during transfer was a DC component (-1.5 kV).
[0170]
First, 100 g of the toner 1 is filled in a cartridge, and an image consisting of only horizontal lines with a printing rate of 3% is obtained in a normal temperature and normal humidity environment (23 ° C., 60% RH) and a low temperature and low humidity environment (15 ° C., 10% RH). An image output test of 6000 sheets was performed using the pattern. The transfer material is 75 g / m²Paper was used.
[0171]
As a result, the toner 1 showed high transferability at the initial stage and after the image was printed out on 6000 sheets, and obtained a good image having no ghost and having excellent halftone reproducibility without fogging to a non-image portion. . Further, it was excellent in low-temperature fixing property and hot offset resistance, and could have a wide fixing temperature range. Table 4 shows the evaluation results under the normal temperature and normal humidity environment, and Table 5 shows the evaluation results under the low temperature and low humidity environment.
[0172]
The evaluation items described in the examples of the present invention and the comparative examples and the criteria thereof will be described.
[0173]
<Fixing temperature range>
A fixing test was performed using a modified LBP-8 Mark #IV. The image area ratio at this time was 25%, and the amount of applied toner per unit area was 0.7 mg / cm.²Set to. The fixing start temperature and the offset start temperature are measured by adjusting the set temperature of the fixing unit every 5 ° C. within a temperature range from 120 ° C. to 210 ° C., outputting a fixed image at each temperature, and obtaining a fixed image. 4.9 kPa (50 g / cm²), And the fixing temperature at which the density reduction rate before and after rubbing was 10% or less was defined as the fixing start temperature. Further, the set temperature was further increased from the fixing start temperature, and the temperature at which the high-temperature offset occurred visually was taken as the offset start temperature.
[0174]
<Transfer efficiency>
The transfer efficiency was determined by tapping off the transfer residual toner on the photoreceptor after transfer of the solid black image with a Mylar tape, peeling off the tape, and setting the Macbeth density value of the paste on paper to C. When the Macbeth density of the tape with the tape attached was D and the Macbeth density of the Mylar tape pasted on the unused paper was E, it was approximately calculated by the following equation.
[0175]
(Equation 2)

[0176]
The transfer efficiency obtained from the above calculation results was determined based on the following criteria.
A: Transfer efficiency is 96% or more.
B: Transfer efficiency is 92% or more and less than 96%.
C: Transfer efficiency is 89% or more and less than 92%.
D: Transfer efficiency is less than 89%.
[0177]
<Fog>
The measurement of fog was measured using REFLECMETER @ MODEL @ TC-6DS manufactured by Tokyo Denshoku Co., Ltd. A green filter was used as a filter, and fog was calculated by the following equation.
[0178]
Fog (reflectance) (%) =
Reflectance on standard paper (%)-Reflectance on non-image area of sample (%)
[0179]
The criteria for fogging are as follows.
A: Very good (less than 1.5%)
B: Good (1.5% or more to less than 2.5%)
C: Normal (2.5% or more to less than 4.0%)
D: Bad (4% or more)
[0180]
<Ghost>
The ghost is determined by outputting the image shown in FIG. 1 and visually determining according to the following criteria.
A: No ghost has occurred.
B: Good image although slight ghost is generated.
C: Image quality with no problem in practice although ghosts are generated.
D: An image with poor ghost and not practically preferable.
[0181]
<Image quality>
The image quality criterion is a comprehensive evaluation of image uniformity and fine line reproducibility. The uniformity of the image is determined based on the uniformity of the solid black image and the halftone image.
A: A clear image with excellent fine line reproducibility and image uniformity.
B: A good image, although the reproducibility of fine lines and the uniformity of the image are slightly inferior.
C: Practically no problem image.
D: An image which is poor in practical use because of poor reproducibility of fine lines and image uniformity.
[0182]
[Examples 2 to 14]
Using toners 2 to 12, 22, and 23 as toners, an image output test and durability evaluation were performed under the same conditions as in Example 1. As a result, there was no problem in the initial image characteristics, and no significant problem was obtained in any case up to 6000 prints. Table 4 shows the evaluation results under the normal temperature and normal humidity environment, and Table 5 shows the evaluation results under the low temperature and low humidity environment.
[0183]
[Example 15]
As an image forming apparatus, a modified LBP-1760 having a structure generally shown in FIG. 5 was used.
[0184]
The potential of the electrostatic image carrier (photosensitive drum 1) is the dark portion potential V_d= -650 V, bright part potential V_L= -130V. The gap between the electrostatic image carrier and the developing sleeve was 270 μm, and a resin layer having a thickness of about 7 μm and a JIS center line average roughness (RA) of 1.0 μm having the following structure was used as a toner carrier. Using a developing sleeve formed on an aluminum cylinder having a diameter of 16φ, a developing magnetic pole is 85 mT (850 gauss), and a urethane blade having a thickness of 1.0 mm and a free length of 0.5 mm is used as a toner regulating member at 39.2 N / m (40 g). / Cm) linear pressure.
Phenol resin 100 parts
Graphite (particle size: about 7μm) 90 parts
Carbon black 10 parts
[0185]
Next, a DC bias component V is used as a developing bias._dc= -450V, superimposed AC bias component V_pp= 1600 V, F = 2200 Hz. The peripheral speed of the developing sleeve was set to 110% (103 mm / sec) in the forward direction with respect to the peripheral speed of the photoconductor (94 mm / sec). The transfer bias was DC 1.5 kV.
[0186]
As a fixing method, an LBP-1760 fixing device that does not have an oil application function and that performs heating and pressure fixing with a heater via a film was used. At this time, a pressure roller having a surface layer of a fluororesin was used, and the diameter of the roller was 30 mm. The fixing temperature was set at 180 ° C., and the nip width was set at 7 mm.
[0187]
The evaluation of the fixing temperature width was performed in the same manner as in Example 1 except that the above fixing device was used.
[0188]
100 g of the toner 20 is filled in a cartridge, and under a normal temperature and normal humidity environment (23 ° C., 60% RH) and a low temperature and low humidity environment (15 ° C., 10% RH), an image pattern composed of only horizontal lines having a printing rate of 3% is used. An image output test was performed. The transfer material is 75 g / m²Paper was used.
[0189]
As a result, the toner 20 exhibited a high transferability at the initial stage and after the image was output on 6000 sheets, and provided a good image having no ghost and having excellent halftone reproducibility without fogging to a non-image portion. . Further, it was excellent in low-temperature fixing property and hot offset resistance, and could have a wide fixing temperature range. Table 4 shows the evaluation results under the normal temperature and normal humidity environment, and Table 5 shows the evaluation results under the low temperature and low humidity environment.
[0190]
[Comparative Examples 1 to 8]
Using toners 13 to 19 and 21 as the toner, an image output test and durability evaluation were performed under the same conditions as in Example 1. As a result, a decrease in transfer efficiency, fog, ghost, and deterioration of image quality occurred together with the durability test. Further, the fixing temperature ranges of the toners 14, 15, and 17 were narrow.
[0191]
[Table 4]

[0192]
[Table 5]

[0193]
【The invention's effect】
By using the toner of the present invention, excellent low-temperature fixability and anti-offset properties are maintained, good toner performance is maintained even in multi-sheet durability, and a high-definition image free of ghost and fog is stably provided for a long period of time. I can do it.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a ghost generated on an image.
FIG. 2 is a conceptual diagram of a peak area (1) on the high molecular side and a peak area (2) on the low molecular side.
FIG. 3 is a diagram illustrating an example of an image forming apparatus suitable for implementing the present invention.
FIG. 4 is a diagram illustrating an example of an image forming method for forming a full-color image.
FIG. 5 is a diagram illustrating an example of an image forming apparatus that can suitably use a magnetic toner.
[Explanation of symbols]
51 charging roller (contact charging member)
52 developing device
54 ° developing sleeve (toner carrier)
55 ° stirring member
56 photoconductor (image carrier, charged object)
57 transfer roller (transfer member)
59 cleaner
63 fixing device

Claims (18)

A toner having a weight average particle size of at least 3 to 10 μm containing at least a binder resin, a colorant and a release agent,
The average circularity of the toner is 0.970 or more;
The release agent has an endothermic peak in the differential thermal analysis (DSC) measurement in the range of 45 to 120 ° C;
The release agent is at least a hydrocarbon wax treated with a styrene-based monomer (hereinafter referred to as a treated wax), and the treated wax is determined by gel permeation chromatography (GPC) of a soluble portion of tetrahydrofuran (THF). Assuming that there are two peaks in the molecular weight measurement, the peak area on the high molecular side is (1) and the peak area on the low molecular side is (2), the area ratio is as follows:
0.2 ≦ (2) / ((1) + (2)) ≦ 0.8 (Equation 1)
Satisfies the following. The treated wax has two peaks in the molecular weight measurement by gel permeation chromatography (GPC) of the soluble portion of tetrahydrofuran (THF), the peak area on the high molecular side is {1}, and the peak on the low molecular side is If the area is (2), the area ratio is
0.2 ≦ (2) / ((1) + (2)) <0.5
The toner according to claim 1, which satisfies the following. 3. The toner according to claim 1, wherein the release agent has an endothermic peak in a range of 50 to 90 ° C. in differential thermal analysis (DSC) measurement. 4. 4. The toner according to claim 1, wherein the mode circularity of the toner is 0.99 or more. The toner according to any one of claims 1 to 4, wherein a ratio of weight average particle diameter / number average particle diameter in the particle size distribution of the toner is 1.40 or less. According to the molecular weight measurement by gel permeation chromatography (GPC) of the soluble portion of the treated wax in tetrahydrofuran (THF), the number average molecular weight (Mn) of (1) was 8,000 or less and the number of (2) The toner according to any one of claims 1 to 5, wherein the average molecular weight (Mn 2) satisfies 200 or more. According to the molecular weight measurement by GPC of the THF-soluble portion of the treated wax, Mn (1) and Mn (2) were represented by the following formulas:
1000 ≦ (Mn <1> -Mn <2>) ≦ 6000 (Equation 2)
The toner according to any one of claims 1 to 6, which satisfies the following. When the molecular weight of the treated wax was measured by GPC based on GPC, the Mn 2 was found to be the following formula: 200 ≦ Mn 2 <2000
And the amount of the wax component graft-modified with a styrene monomer among the wax components having a molecular weight of Mn {2} in the molecular weight measurement by GPC of the THF-soluble portion of the treated wax was defined as A When the amount of the unmodified wax component is B, the following equation is satisfied: 0.08 ≦ {B / (A + B)} × {2} / (1) +2) ≦ 0.78
The toner according to any one of claims 1 to 7, which satisfies the following. When the molecular weight of the treated wax was measured by GPC based on GPC, the Mn 2 was found to be the following formula: 200 ≦ Mn 2 <2000
And the amount of the wax component graft-modified with a styrene monomer among the wax components having a molecular weight of Mn {2} in the molecular weight measurement by GPC of the THF-soluble portion of the treated wax was defined as A When the amount of the unmodified wax component is B, the following equation is satisfied: 0.1 ≦ {B / (A + B)} × {2} / (1) +2)｝ 0.78
The toner according to any one of claims 1 to 7, which satisfies the following. The toner according to any one of claims 1 to 9, wherein the treated wax is contained in an amount of 1 to 30 parts by mass based on 100 parts by mass of the binder resin. 11. The toner according to claim 1, wherein the treated wax is treated with 5 to 100 parts by mass of a styrene monomer based on 100 parts by mass of a hydrocarbon wax. 11. The toner according to claim 1, wherein the treated wax is obtained by treating a hydrocarbon wax with at least a styrene monomer and an unsaturated carboxylic acid monomer. The treated wax is treated with a total of 5 to 100 parts by mass of a styrene monomer and an unsaturated carboxylic acid monomer with respect to 100 parts by mass of a paraffinic wax. 13. The toner according to claim 12, wherein the number of parts by mass is 1 to 20. 14. The toner according to claim 1, wherein the processed wax is obtained by processing a paraffin hydrocarbon wax. The toner (F) having a smaller particle diameter than the toner and the toner (G) having a larger particle diameter than the toner have a larger particle diameter than the toner (G). When the endotherms in the differential thermal analysis (DSC) measurement of the release agent are Hf and Hg,
0.60 ≦ Hg / Hf ≦ 1.50 (Equation 3)
The toner according to any one of claims 1 to 14, which satisfies the following. The endothermic amounts Hf and Hg are 0.80 ≦ Hg / Hf ≦ 1.20 (Equation 4)
The toner according to any one of claims 1 to 14, which satisfies the following. At least a binder resin, a toner produced by a wet method containing a colorant and a release agent,
The toner has a weight average particle diameter of 3 to 10 μm,
The average circularity of the toner is 0.970 or more;
The release agent has an endothermic peak in the differential thermal analysis (DSC) measurement in the range of 45 to 120 ° C;
The release agent is at least a hydrocarbon wax treated with a styrene-based monomer (hereinafter referred to as a treated wax), and the treated wax is determined by gel permeation chromatography (GPC) of a soluble portion of tetrahydrofuran (THF). Assuming that there are two peaks in the molecular weight measurement, the peak area on the high molecular side is (1) and the peak area on the low molecular side is (2), the area ratio is as follows:
0.2 ≦ (2) / ((1) + (2)) ≦ 0.8 (Equation 1)
Satisfies the following. 18. The toner according to claim 17, wherein the release agent has an endothermic peak in the range of 50 to 90 [deg.] C. in differential thermal analysis (DSC) measurement.

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