JP4148410B2 - Toner for developing electrostatic image, process cartridge, and image forming apparatus - Google Patents

Description

＜５＞ トナー体積平均粒径が４〜７．５μｍで、かつ、５μｍ以下の粒子が６０〜８０個数％含有している前記＜１＞から＜４＞のいずれかに記載の静電荷像現像用トナー。
＜６＞ ワックス成分として０．５〜２０重量％のカルナウバワックスを含有するぜんき＜１＞から＜５＞のいずれかに記載の静電荷像現像用トナー。
＜７＞ 感光体と、帯電手段、現像手段、及びクリーニング手段より選ばれる少なくとも一つの手段を一体に支持し、画像形成装置本体に着脱自在に設けられたプロセスカートリッジにおいて、前記現像手段がトナー（現像剤）を保持し、該トナー（現像剤）が前記＜１＞から＜６＞のいずれかに記載の静電荷像現像用トナーであることを特徴とするプロセスカートリッジ。
＜８＞ 少なくとも帯電装置を有し、該帯電装置が潜像担持体に帯電部材を接触させ、該帯電部材に電圧を印加することによって帯電を行うものであって、使用するトナー（現像剤）が前記＜１＞から＜６＞のいずれかに記載の静電荷像現像用トナーであることを特徴とする画像形成装置。
【００２８】
【発明の実施の形態】
以下に本発明を詳細に説明する。
本発明のトナーは、樹脂成分、ワックス成分、着色剤を必須成分として含有する静電荷現像用トナーであって、トナーの飽和磁化σｓが１７．５〜３０ｅｍｕ／ｇであり、該樹脂成分が非線状ポリマー樹脂（Ａ）と線状ポリマー樹脂（Ｂ）と、縮重合系樹脂の原料モノマーと付加重合系樹脂の原料モノマーを含む混合物を用い、同一反応容器中で縮重合反応と付加重合反応を並行反応して行うことにより得られる樹脂（Ｃ）で、（Ａ）、（Ｂ）、（Ｃ）が全て少なくとも同種のポリマーユニットを含有する結着樹脂であり、該着色剤としてチタン成分をＴｉ原子換算でＦｅ原子に対して１０〜４５重量％含有する黒色酸化鉄化合物を用いるものである。
【００２９】
上記黒色酸化鉄化合物の構造としては、Ｆｅ_２Ｏ_３−ＦｅＴｉＯ_３固溶体を含有する多結晶粒子粉末であることが黒色であり、かつ磁性が弱いという点から好ましい。
【００３０】
本発明に係る黒色酸化鉄化合物は、例えば、粒子表面をチタン化合物で被覆したマグネタイト粒子粉末、マグネタイト粒子粉末とチタン化合物との混合粉末又は粒子表面をチタン化合物で被覆したヘマタイト粒子粉末を還元して得られた還元粉末のそれぞれを非酸化性雰囲気下７００℃以上の温度で加熱焼成した後粉砕する方法によって得られる。粒子表面をチタン化合物で被覆したマグネタイト粒子粉末を原料として用いる場合には、磁化値が小さい粒子が得られやすく非磁性という点から好ましい方法である。
【００３１】
マグネタイト粒子粉末、ヘマタイト粒子粉末としては、粒状、球状、針状等いかなる形態の粒子でもよく、また、大きさは０．０３〜１．５μｍ程度の粒子を使用することができる。
【００３２】
原料粒子のサイズと生成物粒子のサイズは、相関があり、小さいサイズの原料粒子を用いると小さいサイズの生成物粒子が、大きいサイズの原料粒子を用いると大きいサイズの生成物粒子が得られる傾向にある。
【００３３】
チタン化合物としては、チタンの含水酸化物、水酸化物、酸化物のいずれをも使用することができる。マグネタイト粒子粉末と混合する場合には水溶性のチタン化合物を用いるのが好ましい。チタン化合物の量は、チタン成分をＴｉ原子換算でＦｅ原子に対して１０〜４５重量の範囲が好ましい。１０重量％未満の場合には、得られる黒色顔料粒子粉末の磁化値が大きくなりトナーの現像能力が低下し、画像濃度が低くなる。４５重量％を超える場合には非磁性の黒色顔料粒子粉末が得られるが、ＴｉＯ_２の生成量が多くなるためＬ値（明度）が高くなりトナー着色力が低下する。
【００３４】
Ｔｉ原子換算でＦｅ原子に対する比率は蛍光Ｘ線分析装置を使用し、得られたメインピークの比率により求めることができる。
【００３５】
黒色酸化鉄化合物の含有量は５〜４５重量部、好ましくは１０〜３０重量部である。５重量部未満の場合、トナーの着色力が不十分となり、トナーが赤味を帯びた色になる。また、定着温度が充分に低下しない。４５重量部を超えた場合は、トナーの比重が大きくなりすぎて、現像能力が低下する。
【００３６】
本発明では、トナーの飽和磁化σｓは０．５〜３０ｅｍｕ／ｇであることが好ましい。トナーの飽和磁化が３０ｅｍｕ／ｇを超えた場合、磁気スリーブ、磁気ブラシなどの磁石を内蔵したトナー担持体との保持力が強くなり、感光体への現像性が悪化する。０．５ｅｍｕ／ｇ未満の場合は、トナー担持体との保持力が弱くなり、トナー飛散、地汚れが悪化する。
トナーの飽和磁化の測定は、理研電子（株）製の磁化測定装置ＢＨＵ−６０を用い、内径７ｍｍφ、高さ１０ｍｍのセルに充填したトナーに、磁界を１０ｋＯｅまで掃引した際の履歴曲線から飽和磁化を求めた。
【００３７】
本発明では、トナー中に含有する黒色酸化鉄化合物の平均一次粒径は０．０５〜２．０μｍ、トナー中での分散性の観点から０．１〜０．５μｍ範囲にあることが特に好ましい。
黒色酸化鉄化合物の平均１次粒子径は、日立透過型電子顕微鏡Ｈ−９０００による電子顕微鏡写真から測定した数値の平均値で示した。
【００３８】
樹脂の特徴に関しては、これまで以上の省エネルギーを達成するためのトナー低温定着化として、低温定着性を有する線状ポリマー（Ｂ）と、耐ホットオフセット性を有する非線状ポリマー（Ａ）で、（Ａ）、（Ｂ）が同種のポリマーを使用することで、樹脂の分散性を高め定着可能温度範囲を広げることが可能であった。しかし、従来の低温定着性の高いポリマー樹脂のみを混合して使用した場合、樹脂が柔らかいこととポリマー自身の相溶性が良いために、樹脂が割れにくくなり生産性の悪化を招き、また耐熱保存性も不十分であった。
【００３９】
そこで、本発明では、（Ａ）、（Ｂ）と同種のポリマーユニットを含むハイブリッド樹脂（Ｃ）を加えることにより非線状ポリマーと線状ポリマーに適度に相溶させることで、粉砕性と耐熱保存性を損なうことなく幅広い定着可能温度幅とかぶりなどの画像品質を満足するトナーを提供できることを見出した。（Ａ）、（Ｂ）、（Ｃ）のポリマーユニットが異なった場合、それぞれの相溶性の差が大きくなり、カーボンや帯電制御剤の分散が不良となり、かぶりの不具合を生じた。
【００４０】
また特に、該ポリマー（Ａ）とポリマー（Ｂ）とハイブリッド樹脂（Ｃ）の軟化点（Ｔｍ）とガラス転移点（Ｔｇ）が下記式（Ｉ）〜（ＩＩＩ）を満足した場合、更なる定着可能温度幅と粉砕性を高めることが可能であった。
【００４１】
【数３】
Ｔｍ（Ａ）＞Ｔｍ（Ｃ）＞Ｔｍ（Ｂ） （Ｉ）
｜Ｔｇ（Ａ）−Ｔｇ（Ｂ）｜＜１０（℃） （ＩＩ）
３０≦Ｔｍ（Ａ）−Ｔｍ（Ｂ）≦６０（℃） （ＩＩＩ）
Ｔｍ（Ａ）＞Ｔｍ（Ｃ）＞Ｔｍ（Ｂ）を満足することによって、かぶりに改善効果が有った。これは、ハイブリッド樹脂（Ｃ）がポリマー（Ａ）とポリマー（Ｂ）をうまく分散させるためと考えられる。また、Ｔｇ（Ａ）−Ｔｇ（Ｂ）が１０℃以上の場合はトナー混練時に相溶性が悪くなり、低温定着性とホットオフセット性の両立が困難であった。より好ましくは７℃以下である。また、Ｔｍ（Ａ）−Ｔｍ（Ｂ）が３０℃〜６０℃とすることで低温定着性とホットオフセット性が両立でき十分な定着可能温度領域を保つことが出来た。より好ましくは、３５〜５５℃である。
【００４２】
また、トナー体積平均粒径が４〜７．５μｍであり、かつ５μｍ以下の粒子が６０〜８０個数％の粒度分布を持った場合において細線再現性に優れていた。
体積平均粒径が４μｍ未満では、転写効率の低下、ブレードクリーニング性の低下といった現象が発生しやすい。体積平均粒径が７．５μｍを超えると、文字やラインの飛び散りを抑えることが難しい。
５μｍ以下の粒子が６０％未満だと、細線の再現性が悪化する。５μｍ以下の粒子が８０％を超えると、微粉が多すぎて、現像スリーブ固着が悪化する。
【００４３】
次に、トナー粒子の粒度分布の測定方法について説明する。
コールターカウンター法によるトナー粒子の粒度分布の測定装置としては、コールターカウンターＴＡ−ＩＩやコールターマルチサイザーＩＩ（いずれもコールター社製）が挙げられる。以下に測定方法について述べる。
まず、電解水溶液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加える。ここで、電解液とは１級塩化ナトリウムを用いて約１％ＮａＣｌ水溶液を調製したもので、例えばＩＳＯＴＯＮ−ＩＩ（コールター社製）が使用できる。ここで、更に測定試料を２〜２０ｍｇ加える。試料を懸濁した電解液は、超音波分散器で約１〜３分間分散処理を行い、前記測定装置により、アパーチャーとして１００μｍアパーチャーを用いて、トナー粒子又はトナーの体積、個数を測定して、体積分布と個数分布を算出する。得られた分布から、トナーの重量平均粒径（Ｄ４）、個数平均粒径（Ｄ１）を求めることができる。
【００４４】
チャンネルとしては、２．００〜２．５２μｍ未満；２．５２〜３．１７μｍ未満；３．１７〜４．００μｍ未満；４．００〜５．０４μｍ未満；５．０４〜６．３５μｍ未満；６．３５〜８．００μｍ未満；８．００〜１０．０８μｍ未満；１０．０８〜１２．７０μｍ未満；１２．７０〜１６．００μｍ未満；１６．００〜２０．２０μｍ未満；２０．２０〜２５．４０μｍ未満；２５．４０〜３２．００μｍ未満；３２．００〜４０．３０μｍ未満の１３チャンネルを使用し、粒径２．００μｍ以上乃至４０．３０μｍ未満の粒子を対象とする。
【００４５】
本発明では、ワックス成分としてカルナウバワックス、ライスワックス及びエステルワックスの少なくとも一つを含有することが好ましい。
カルナウバワックスはカルナウバヤシの葉から得られる天然のワックスであるが、特に遊離脂肪酸脱離した低酸価タイプのものが結着樹脂中に均一分散が可能であるので好ましい。
ライスワックスは米糠から抽出される米糠油を精製する際に、脱ろうまたはウィンタリング工程で製出される粗ろうを精製して得られる天然ワックスである。エステルワックスは単官能直鎖脂肪酸と単官能直鎖アルコールからエステル反応で合成される。
これらのワックス成分は単独または併用して使用される。ワックス成分の添加量は０．５〜２０重量部、さらに好ましくは２〜１０重量部である。
本発明では、カルナウバワックス、ライスワックス、合成エステルワックスの他のワックス成分も使用可能である。例えば、ポリプロピレンワックス、ポリエチレンワックス等のようなポリオレフィンワックスなどである。
【００４６】
次に本発明のトナーに用いられる材料について詳細に説明する。
本発明で用いるポリマー樹脂としては、ポリエステル、ポリアミド、ポリエステル・ポリアミド樹脂等の縮重合反応により得られるポリマー樹脂、もしくはスチレンアクリル、スチレンブタジエン等の付加重合反応により得られるポリマー樹脂すべてが使用可能である。また、縮重合反応もしくは付加重合反応によって得られるポリマーであれば何等限定されない。
【００４７】
本発明で用いられるポリエステル樹脂としては、多価ヒドロキシ化合物と多塩基酸との縮重合によって得られるポリマーである。多価ヒドロキシ化合物としては、例えばエチレングリコール、ジエチレングリコール、トリエチレングリコール、プロピレングリコール等のグリコール類、１，４−ビス（ヒドロキシメチル）シクロヘキサン等の２つのヒドロキシル基を含有する脂環式化合物、ビスフェノールＡ等の２価フェノール化合物等を挙げることができる。また、多価ヒドロキシ化合物には、ヒドロキシル基を３個以上含むものを包含される。
【００４８】
多塩基酸としては、例えばマレイン酸、フマル酸、フタル酸、イソフタル酸、テレフタル酸、コハク酸、マロン酸等の２価カルボン酸の他、１，２，４−ベンゼントリカルボン酸、１，２，５−ベンゼントリカルボン酸、１，２，４−シクロヘキサントリカルボン酸、１，２，４−ナフタレントリカルボン酸、１，２，５−ヘキサントリカルボン酸、１，３−ジカルボキシル−２−メチレンカルボキシプロパン、１，２，７，８−オクタンテトラカルボン酸等の３価以上の多価カルボン酸単量体を挙げることができる。
【００４９】
ポリエステル・ポリアミド、ポリアミドの原料モノマーとしては、上記モノマー原料以外に、アミド成分を形成するモノマーとして、例えば、エチレンジアミン、ペンタメチレンジアミン、ヘキサメチレンジアミン、フェニレンジアミン、トリエチレンテトラミン等のポリアミン、６−アミノカプロン酸、ε−カプロラクタム等のアミノカルボン酸等が挙げられる。ここで、樹脂のガラス転位温度Ｔｇは熱保存性の関係から５５℃以上がよく、より好ましくは５７℃以上が良い。
【００５０】
付加重合反応で得られるポリマー樹脂としては、ラジカル重合によりビニル系樹脂が代表的であるが、特に限定されるものではない。付加重合系樹脂の原料モノマーとしては、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、α−メチルスチレン、ｐ−エチルスチレン、ビニルナフタレン、例えばエチレン、プロピレン、ブチレン、イソブチレン等のエチレン系不飽和モノオレフィン類、例えば塩化ビニル、臭化ビニル、酢酸ビニル、ぎ酸ビニル等のビニルエステル類、例えばアクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ｎ−プロピル、アクリル酸イソプロピル、アクリル酸ｔｅｒｔ−ブチル、アクリル酸アミル、メタクリル酸、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、メタクリル酸イソプロピル、メタクリル酸ｔｅｒｔ−ブチル、メタクリル酸アミル、メタクリル酸ステアリル、メタクリル酸メトキシエチル、メタクリル酸グリシジル、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エチレン性モノカルボン酸及びそのエステル、例えばアクリロニトリル、メタクリロニトリル、アクリルアミド等のエチレン性モノカルボン酸置換体、マレイン酸ジメチル等のエチレン性ジカルボン酸及びその置換体、例えばビニルメチルケトン等のビニルケトン類が挙げられる。また、必要に応じて架橋剤を添加することができる。付加重合系モノマーの架橋剤としては、例えばジビニルベンゼン、ジビニルナフタレン、ポリエチレングリコールジメタクリレート、ジエチレングリコールジメタクリレート、トリエチレングリコールジアクリレート、ジプロピレングリコールジメタクリレート、ポリプロピレングリコールジメタクリレート、フタル酸ジアリルなど、一般の架橋剤を用いることができる。
【００５１】
これら架橋剤の使用量は、付加重合系樹脂の原料モノマー１００部を基準として、０．０５〜１５重量部、より好ましくは０．１〜１０重量部である。０．０５重量部未満の場合は架橋剤の効果がない。１５重量部を超えた場合、熱による溶融が困難となり、熱を用いて定着する際にトナーが定着不良となる。
【００５２】
また、付加重合系樹脂の原料モノマーを重合させる際に重合開始剤を使用する。例えば、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、その他のアゾ系またはジアゾ系重合開始剤、又は、ベンゾイルパーオキサイド、メチルエチルケトンパーオキサイド、２，４−ジクロロベンゾイルパーオキサイド等の過酸化物重合開始剤が挙げられる。これらは、重合体の分子量及び分子量分布を調節する目的で二種類以上の重合開始剤を混合して使用することもできる。重合開始剤の使用量は、付加重合系樹脂の原料モノマー１００部を基準として、０．０５〜１５重量部、より好ましくは０．５〜１０重量部である。
【００５３】
これら縮重合反応もしくは付加重合反応においては、反応原料等の相違によって、得られるポリマー樹脂は、非線状の構造を有するポリマーとなる場合と線状の構造を有するポリマーとなる場合がある。本発明においては、非線状ポリマー樹脂（Ａ）と線状ポリマー樹脂（Ｂ）の両方を使用するものである。
本発明で言う非線状ポリマー樹脂とは実質的な架橋構造を有するポリマー樹脂を意味し、線状ポリマー樹脂とは架橋構造を実質的に有しないポリマー樹脂を意味する。
【００５４】
本発明においては、縮重合系樹脂と付加重合系樹脂が化学的に結合されたハイブリッド樹脂を得るため、両樹脂のモノマーのいずれとも反応しうる化合物を用いて重合するのが好ましい。このような両反応性モノマーとしては、フマル酸、アクリル酸、メタクリル酸、マレイン酸、フマル酸ジメチル等の化合物が挙げられる。
両反応性モノマーの使用量は、付加重合系樹脂の原料モノマー１００部を基準として、１〜２５重量部、好ましくは２〜１０重量部である。１重量部より少ないと着色剤や帯電制御剤の分散が悪くかぶりなどの画像品質が悪化した。２５重量部より多いと樹脂がゲル化してしまう不具合があった。
【００５５】
以上のようなハイブリッド樹脂は、両反応の進行及び完了を同時にする必要はなく、それぞれの反応温度、時間を選択して、独立に反応の進行を完了することができる。例えば、反応容器中にポリエステル樹脂の縮重合系原料モノマーの混合物中に、ビニル系樹脂の付加重合系原料モノマー及び重合開始剤からなる混合物を滴下してあらかじめ混合し、まずラジカル反応によりビニル系樹脂からなる重合反応を完了させ、次に反応温度を上昇させることにより縮重合反応によりポリエステル樹脂からなる縮重合反応を完了させる方法がある。この方法により、反応容器中で独立した２つの反応を並行して進行させることにより、２種の樹脂を効果的に分散させることが可能である。
【００５６】
本発明において、トナー中の樹脂成分として、上記記載の樹脂以外の樹脂を、トナーの性能を損なわない範囲で、併用することもできる。この場合の使用可能な樹脂としては、例えば次のようなものが挙げられるが、これらに限定はされない。ポリウレタン樹脂、シリコーン樹脂、ケトン樹脂、石油系樹脂、水素添加された石油系樹脂。これらの樹脂は単独使用に限らず、二種以上併用することもできる。また、これらの製造法も特に限定されるものではなく、塊状重合、溶液重合、乳化重合、懸濁重合のいずれも利用できる。
【００５７】
本発明のトナーにおいては、極性を制御するために、極性制御を配合することが可能である。この場合の極性制御剤としては、例えばニグロシン系染料、四級アンモニウム塩、アミノ基含有のポリマー、含金属アゾ染料、サリチル酸の錯化合物、フェノール化合物などが挙げられる。
【００５８】
本発明のトナーの製造方法は、従来公知の方法でよく、樹脂成分、着色剤、ワックス成分、その他場合によっては荷電制御剤等をミキサー等を用いて混合し、熱ロール、エクストルーダー等の混練機を用い混練した後、冷却固化し、これをジェットミル等の粉砕機で粉砕し、その後分級して得られる。
【００５９】
上記トナーには必要に応じてその他、添加剤を添加する事も可能である。添加剤としては、シリカ、酸化アルミニウム類、酸化チタン類を例示することができる。高流動性を付与する事を主目的する場合には疎水化処理シリカあるいはルチル型微粒子酸化チタンとして平均一次粒径が０．００１〜１μｍ、好ましくは０．００５〜０．１μｍの範囲ものから適宜選択でき、特に有機シラン表面処理シリカあるいはチタニアが好ましく、通常０．１〜５重量％、好ましくは０．２〜２重量％の割合で使用される。
【００６０】
また、例えば本発明のトナーを二成分系乾式トナーとして使用する場合に混合して使用するキャリアとしては、ガラス、鉄、フェライト、ニッケル、ジルコン、シリカ等を主成分とする、粒径３０〜１０００μｍ程度の粉末、または、該粉末を芯材としてスチレン−アクリル系樹脂、シリコーン系樹脂、ポリアミド系樹脂、ポリフッ化ビニリデン系樹脂等をコーティングしたものから適宜選択して使用可能である。
【００６１】
上記本発明のトナーをプロセスカートリッジを有する画像形成装置に装填して画像形成を行う場合も優れた効果を奏する。すなわち、上記本発明のトナーを用いることにより、画質の優れたプロセスカートリッジを提供することができる。
【００６２】
図１はプロセスカートリッジの概略の構成例を示すもので、１はプロセスカートリッジ全体を示し、２は感光体、３は帯電手段、４は現像手段、５はクリーニング手段を示す。
【００６３】
プロセスカートリッジを有する画像形成装置において、感光体が所定の周速度で回転駆動される。感光体２は回転過程において、帯電手段３によりその周面に正または負の所定電位の均一帯電を受け、次いで、スリット露光やレーザービーム走査露光等の像露光手段からの画像露光光を受け、こうして感光体２の周面に静電潜像が順次形成され、形成された静電潜像は、次いで現像手段４によりトナー現像され、現像されたトナー像は、給紙部から感光体と転写手段との間に感光体の回転と同期されて給送された転写材に、転写手段により順次転写されていく。像転写を受けた転写材は感光体面から分離されて像定着手段へ導入されて像定着され、複写物（コピー）として装置外へプリントアウトされる。像転写後の感光体の表面は、クリーニング手段５によって転写残りトナ−の除去を受けて清浄面化され、更除電された後、繰り返し画像形成に使用される。
【００６４】
さらにまた本発明のトナーを接触式の帯電装置を有する画像形成装置に用いて画像形成を行う場合も優れた効果を奏する。すなわち、上記本発明のトナーを用いることにより、オゾンが低減された帯電装置を採用する画像形成装置を提供することができる。
【００６５】
図３にローラ帯電を行う帯電装置を用いた画像形成装置の一例の概略構成を示した。被帯電体、像担持体としての感光体１０は矢印の方向に所定の速度（プロセススピード）で回転駆動される。この感光ドラム１０に接触させた帯電部材である帯電ローラ１１は芯金１２とこの芯金１２の外周に同心一体にローラ上に形成した導電ゴム層１３を基本構成とし、芯金１２の両端を不図示の軸受け部材などで回転自由に保持させると供に、不図示の加圧手段によって感光ドラムに所定の加圧力で押圧させており、本図３の場合はこの帯電ローラ１１は感光ドラム１０の回転駆動に従動して回転する。帯電ローラ１１は、直径９ｍｍの芯金上に１００，０００Ω・ｃｍ程度の中抵抗ゴム層を被膜して直径１６ｍｍに形成されている。
帯電ローラ１１の芯金１２と図示の電源１４とは電気的に接続されており、電源１４により帯電ローラ１１に対して所定のバイアスが印加される。これにより感光体１０の周面が所定の極性、電位に一様に帯電処理される。
【００６６】
図４にブラシ帯電を行う帯電装置を用いた画像形成装置の一例の概略構成を示した。被帯電体、像担持体としての感光体２０は矢印の方向に所定の速度（プロセススピード）で回転駆動される。この感光体２０に対して、ファーブラシまたは磁気ブラシによって構成されるブラシローラ２１が、ブラシ部２３の弾性に抗して所定の押圧力をもって所定のニップ幅で接触させてある。
【００６７】
本例における接触帯電部材としてのファーブラシローラ２１は、電極を兼ねる直径６ｍｍの金属製の芯金２２に、ブラシ部２３としてユニチカ（株）製の導電性レーヨン繊維ＲＥＣ−Ｂをパイル地にしたテープをスパイラル状に巻き付けて、外径１４ｍｍ、長手長さ２５０ｍｍのロールブラシとしたものである。ブラシ部２３のブラシは３００デニール／５０フィラメント、１平方ミリメートル当たり１５５本の密度である。このロールブラシを内径が１２ｍｍのパイプ内に一方向に回転させながらさし込み、ブラシと、パイプが同心となるように設定し、高温多湿雰囲気中に放置してクセ付けで斜毛させた。
ファーブラシローラ２１の抵抗値は印加電圧１００Ｖにおいて１×１０^５Ωである。この抵抗値は、金属製の直径φ３０ｍｍのドラムにファーブラシローラ２１をニップ幅３ｍｍで当接させ、１００Ｖの電圧を印加したときに流れる電流から換算した。
【００６８】
ファーブラシ帯電器の抵抗値は、被帯電体である感光体２０上にピンホール等の低耐圧欠陥部が生じた場合にもこの部分に過大なリーク電流が流れ込んで帯電ニップ部が帯電不良になる画像不良を防止するために１０^４Ω以上必要であり、感光体表面に十分に電荷を注入させるために１０^７Ω以下である必要がある。
また、ブラシの材質としては、ユニチカ（株）製のＲＥＣ−Ｂ以外にも、ＲＥＣ−Ｃ、ＲＥＣ−Ｍ１、ＲＥＣ−Ｍ１０、さらに東レ（株）製のＳＡ−７、日本蚕毛（株）製のサンダーロン、カネボウ製のベルトロン、クラレ（株）のクラカーボ、レーヨンにカーボンを分散したもの、三菱レーヨン（株）製のローバル等が考えられる。ブラシは一本が３〜１０デニールで、１０〜１００フィラメント／束、８０〜６００本／ｍｍの密度が好ましい。毛足は１〜１０ｍｍが好ましい。
【００６９】
このファーブラシローラ２１は感光体２０の回転方向と逆方向（カウンター）に所定の周速度（表面の速度）をもって回転駆動され、感光体面に対して速度差を持って接触する。そしてこのファーブラシローラ２１に電源２４から所定の帯電電圧が印加されることで、回転感光体面が所定の極性・電位に一様に接触帯電処理される。
本例では該ファーブラシローラ２１による感光体２０の接触帯電は直接注入帯電が支配的となって行なわれ、回転感光体表面はファーブラシローラ２１に対する印加帯電電圧とほぼ等しい電位に帯電される。
【００７０】
磁気ブラシ帯電の場合も上記ファーブラシ帯電の場合と同様、感光体に対して磁気ブラシによって構成されるブラシローラ２１が、ブラシ部２３の弾性に抗して所定の押圧力をもって所定のニップ幅で接触させる。
接触帯電部材としての磁気ブラシとしては、平均粒径：２５μｍのＺｎ−Ｃｕフェライト粒子と、平均粒径１０μｍのＺｎ−Ｃｕフェライト粒子を、重量比１：０．０５で混合して、それぞれの平均粒径の位置にピークを有する平均粒径２５μｍのフェライト粒子を、中抵抗樹脂層でコートした磁性粒子を用いた。接触帯電部材は、上述で作製された被覆磁性粒子、及び、これを支持させるための非磁性の導電スリーブ、これに内包されるマグネットロールによって構成され、上記被覆磁性粒子をスリーブ上に、厚さ１ｍｍでコートして、感光体との間に幅約５ｍｍの帯電ニップを形成した。また、該磁性粒子保持スリーブと感光体との間隙は、約５００μｍとした。さらに、マグネットロールは、スリーブ表面が、感光体表面の周速に対して、その２倍の早さで逆方向に摺擦するように、回転され、感光体と磁気ブラシとが均一に接触するようにした。
【００７１】
【実施例】
次に実施例によって本発明をさらに詳細に説明する。ただし、本発明は以下の実施例によって限定されるものではない。なお、実施例中、部はすべて重量部を表す。
【００７２】
まず樹脂の製造例を示す。
非線状ポリエステル樹脂の製造
フマル酸：１０ｍｏｌ、無水トリメリット酸：４ｍｏｌ、ビスフェノールＡ（２，２）プロピレンオキサイド：６ｍｏｌ、ビスフェノールＡ（２，２）エチレンオキサイド：４ｍｏｌをステンレス攪拌棒、流下式コンデンサー、窒素ガス導入管及び温度計を装備したフラスコに入れ、窒素雰囲気下で２２０℃の温度で攪拌しつつ縮重合反応を行い非線状ポリエステル樹脂を得た。
【００７３】
線状ポリエステル樹脂の製造
テレフタル酸：８ｍｏｌ、無水トリメリット酸：３ｍｏｌ、ビスフェノールＡ（２，２）プロピレンオキサイド：６ｍｏｌ、ビスフェノールＡ（２，２）エチレンオキサイド：４ｍｏｌをステンレス攪拌棒、流下式コンデンサー、窒素ガス導入管及び温度計を装備したフラスコに入れ、窒素雰囲気下で２２０℃の温度で攪拌しつつ縮重合反応を行い線状ポリエステル樹脂を得た。
【００７４】
ハイブリッド樹脂の製造
付加重合反応モノマーとしてスチレン２０ｍｏｌ、ブチルメタクリレート５ｍｏｌ、重合開始剤としてｔ−ブチルハイドロパーオキサイド０．４ｍｏｌを滴下ロートに入れ、付加重合、縮重合両反応性モノマーとしてフマル酸：１０ｍｏｌ、縮重合反応モノマーとして無水トリメリット酸：４ｍｏｌ、ビスフェノールＡ（２，２）プロピレンオキサイド：６ｍｏｌ、ビスフェノールＡ（２，２）エチレンオキサイド：４ｍｏｌ、エステル化触媒としてジブチルスズオキシド６０ｍｏｌをステンレス攪拌棒、流下式コンデンサー、窒素ガス導入管及び温度計を装備したフラスコに入れ、窒素雰囲気下にて１３５℃で攪拌しつつ、滴下ロートより付加重合系原料をあらかじめ混合したものを５時間かけて滴下した。終了後１３５℃に保ったまま６時間熟成した後、２２０℃に昇温して反応して、ハイブリッド樹脂を得た。
【００７５】
ポリマーの重合度は、ＡＳＴＭ Ｅ２８−６７に準拠した軟化点より追跡を行い、所定の軟化点に達したときに反応を終了し、容器から抜き出し、冷却後粉砕して表１に示す特性値を持ったポリマーを得た。
表１に実施例１〜９及び比較例１〜４で使用したポリエステル樹脂の物性値を示す。
【００７６】
【表１】

【００７７】
軟化温度は高化式フローテスター（島津製作所製）を用いてＪＩＳ Ｋ７２１０１に記載された方法に準拠して行った。１ｃｍ^３の試料を昇温速度６℃／ｍｉｎで加熱しながら、プランジャーにより２０Ｋｇ／ｃｍ^２の荷重を与え、直径１ｍｍ、長さ１ｍｍのノズルを押し出すようにし、これにより、プランジャー降下量−温度曲線を描き、そのＳ字曲線の高さをｈとするとき、ｈ／２に対応する温度（樹脂の半分が流出した温度）を軟化点とする。
ガラス転移点は島津製作所製示差走査熱量計ＤＳＣ−６０を用いて、１０℃／分で室温から２００℃まで昇温した後、降温速度１０℃／分で室温まで冷却した後、昇温速度１０℃／分で測定した際に、ガラス転移点以下のベースラインとガラス転移点以上のベースラインの高さｈが１／２に相当する曲線をガラス転移点（Ｔｇ）とする。
【００７９】
比較例１
非線状ポリエステル樹脂（Ａ） Ｍｗ：８万 ４０部
線状ポリエステル樹脂（Ｂ） Ｍｗ：１万 ４５部
ハイブリッド樹脂（Ｃ） １５部
ポリエステル（Ｍｗ５万）／スチレン−アクリル（Ｍｗ２０万）＝８０／２０
Ｔｉ−Ｆｅ着色剤 ２５部
（Ｔｉ含有量：８．０重量％、平均一次粒径０．０３μｍ）
荷電制御剤（スピロンブラックＴＲ−Ｈ：保土谷化学） ２部
低分子ポリプロピレン ３部
上記組成の混合物をヘンシェルミキサー中で十分攪拌混合した後、ロールミルで１３０〜１４０℃の温度で約３０分間加熱溶融し、室温まで冷却後、得られた混練物をジェットミルで粉砕分級し、体積平均粒径８．０μｍでかつ５μｍ以下粒子が３５個数％の粒径分布を持ったトナーを得た。添加剤（Ｒ−９７２：クラリアントジャパン製）をトナー１００部に対して０．８部添加し、ヘンシェルミキサーで攪拌混合後メッシュを通して大粒径の粒子を削除し最終トナーを得た。
トナーの飽和磁化σｓは３５ｅｍｕ／ｇであった。
本トナーと、平均粒径８０μｍの球形フェライト粒子にシリコーン樹脂コートしたキャリアで、トナー濃度２．５重量部の現像剤を調製した。
【００８０】
比較例２
（トナー処方）
非線状ポリエステル樹脂（Ａ） Ｍｗ：８万 ４０部
線状ポリエステル樹脂（Ｂ） Ｍｗ：１万 ４５部
ハイブリッド樹脂（Ｃ） １５部
ポリエステル（Ｍｗ５万）／スチレン−アクリル（Ｍｗ２０万）＝８０／２０
Ｔｉ−Ｆｅ着色剤 ２５部
（Ｔｉ含有量：５０重量％、平均一次粒径０．４５μｍ）
荷電制御剤（スピロンブラックＴＲ−Ｈ：保土谷化学） ２部
低分子ポリプロピレン ３部
（重量平均分子量：６０００）
上記組成の混合物をヘンシェルミキサー中で十分攪拌混合した後、ロールミルで１３０〜１４０℃の温度で約３０分間加熱溶融し、室温まで冷却後、得られた混練物をジェットミルで粉砕分級し、体積平均粒径８．０μｍでかつ５μｍ以下粒子が３５個数％の粒径分布を持ったトナーを得た。添加剤（Ｒ−９７２：クラリアントジャパン製）をトナー１００部に対して０．８部添加し、ヘンシェルミキサーで攪拌混合後メッシュを通して大粒径の粒子を削除し最終トナーを得た。
トナーの飽和磁化σｓは０．４ｅｍｕ／ｇであった。
本トナーと、平均粒径８０μｍの球形フェライト粒子にシリコーン樹脂コートしたキャリアで、トナー濃度２．５重量部の現像剤を調製した。
【００８１】
比較例３
実施例１のハイブリッド樹脂（Ｃ）を除いた以外は、実施例１と同様な現像剤を得た。
【００８２】
比較例４
実施例１のハイブリッド樹脂（Ｃ）を、スチレン−メチルメタアリレート共重合体（Ｍｗ：５万、酸価：２３．３ｍｇＫＯＨ／ｇ Ｔｍ：１０９．７℃ Ｔｇ：６２．５℃）に変更した以外は、実施例１と同様な現像剤を得た。
【００８３】
実施例２
（トナー処方）
非線状ポリエステル樹脂（Ａ） Ｍｗ：８万 ４０部
線状ポリエステル樹脂（Ｂ） Ｍｗ：１万 ４５部
ハイブリッド樹脂（Ｃ） １５部
ポリエステル（Ｍｗ５万）／スチレン−アクリル（Ｍｗ２０万）＝８０／２０
Ｔｉ−Ｆｅ着色剤 ２０部
（Ｔｉ含有量：２５重量％、平均一次粒径０．０３μｍ）
荷電制御剤（スピロンブラックＴＲ−Ｈ：保土谷化学） ２部
低分子ポリプロピレン ３部
（重量平均分子量：６０００）
上記組成の混合物をヘンシェルミキサー中で十分攪拌混合した後、ロールミルで１３０〜１４０℃の温度で約３０分間加熱溶融し、室温まで冷却後、得られた混練物をジェットミルで粉砕分級し、体積平均粒径８．０μｍでかつ５μｍ以下粒子が３５個数％の粒径分布を持ったトナーを得た。添加剤（Ｒ−９７２：クラリアントジャパン製）をトナー１００部に対して０．８部添加し、ヘンシェルミキサーで攪拌混合後メッシュを通して大粒径の粒子を削除し最終トナーを得た。
トナーの飽和磁化σｓは３．５ｅｍｕ／ｇであった。
本トナーと、平均粒径８０μｍの球形フェライト粒子にシリコーン樹脂コートしたキャリアで、トナー濃度２．５重量部の現像剤を調製した。
【００８４】
実施例３
非線状ポリエステル樹脂（Ａ） Ｍｗ：８万 ４０部
線状ポリエステル樹脂（Ｂ） Ｍｗ：１万 ４５部
ハイブリッド樹脂（Ｃ） １５部
ポリエステル（Ｍｗ５万）／スチレン−アクリル（Ｍｗ２０万）＝８０／２０
Ｔｉ−Ｆｅ着色剤 ２５部
（Ｔｉ含有量：１５重量％、平均一次粒径０．２５μｍ）
荷電制御剤（スピロンブラックＴＲ−Ｈ：保土谷化学） ２部
低分子ポリプロピレン ３部
（重量平均分子量：６０００）
上記組成の混合物をヘンシェルミキサー中で十分攪拌混合した後、ロールミルで１３０〜１４０℃の温度で約３０分間加熱溶融し、室温まで冷却後、得られた混練物をジェットミルで粉砕分級し、体積平均粒径８．０μｍでかつ５μｍ以下粒子が３５個数％の粒径分布を持ったトナーを得た。添加剤（Ｒ−９７２：クラリアントジャパン製）をトナー１００部に対して０．８部添加し、ヘンシェルミキサーで攪拌混合後メッシュを通して大粒径の粒子を削除し最終トナーを得た。
トナーの飽和磁化σｓは１７．５ｅｍｕ／ｇであった。
本トナーと、平均粒径８０μｍの球形フェライト粒子にシリコーン樹脂コートしたキャリアで、トナー濃度２．５重量部の現像剤を調製した。
【００８５】
実施例４
実施例３のハイブリッド樹脂を表１の実施例４で示すような特性を持った樹脂に変更した以外は、実施例３と同様にして現像剤を得た。
【００８６】
実施例５
実施例４の非線状樹脂及び線状樹脂を表１の実施例５で示すような特性を持った樹脂に変更した以外は、実施例４と同様にして現像剤を得た。
【００８７】
実施例６
実施例５の非線状樹脂及び線状樹脂を表１の実施例６で示すような特性を持った樹脂に変更した以外は、実施例５と同様にして現像剤を得た。
【００８８】
実施例７
実施例６の非線状樹脂及び線状樹脂を表１の実施例７で示すような特性を持った樹脂に変更した以外は、実施例６と同様にして現像剤を得た。
【００８９】
実施例８
実施例７のトナーの粒径分布を体積平均粒径６．５μｍであり５μｍ以下が６５個数％である粒度分布を持ったトナーに変更した以外は、実施例７と同様にして現像剤を得た。
【００９０】
実施例９
実施例８の低分子ポリプロピレンをカルナウバワックスに変更した以外は、実施例８と同様にして現像剤を得た。
【００９１】
各現像剤の評価は以下のように行い、評価結果を表２及び表３に示す。
（定着性）
定着ローラーとしてテフロンローラーを使用した（株）リコー製複写機 ＭＦ−２００の定着部を改造した装置を用いて、これにリコー製のタイプ６２００紙をセットし複写テストを行った。定着温度を変えてホットオフセット発生温度を求めた。尚コールドオフセットの評価条件は、紙送りの線速度を１４０ｍｍ／ｓｅｃ、面圧１．２Ｋｇｆ／ｃｍ^２、ニップ幅３ｍｍ、高温オフセットの評価条件は紙送りの線速度を５０ｍｍ／ｓｅｃ、面圧２．０Ｋｇｆ／ｃｍ^２、ニップ幅４．５ｍｍと設定した。
コールドオフセット発生温度及び高温オフセット発生温度を以下のように求めた。
（コールドオフセット）良 ◎：１２５℃未満、○：１２５〜１３５、□：１３５〜１４５、△：１４５〜１５５、×：１５５以上 悪
（ホットオフセット） 良 ◎：２０１℃以上、○：２００〜１９１℃、□：１９０〜１８１℃、△：１８０〜１７１、×：１７０以下 悪
の５段階で行った。
【００９２】
（粉砕性評価）
平均粒径１ｍｍ以下に破砕されているトナーを、日本ニューマチックの社製のＩＤＳ型粉砕機で一定条件下に粉砕した時の単位時間当たりの処理量により求め、次の判定基準により評価した。
良 ◎：７ｋｇ以上、○：７〜５ｋｇ，□：５〜３ｋｇ，△：３〜２ｋｇ、×：２ｋｇ未満 悪
【００９３】
（かぶり評価）
かぶり評価は、初期と１０万枚後の非画像部の付着しているトナー濃度を、次の判断基準により５段階で評価を行った。
良 ◎：大変良い、○：良い、□：普通、△：悪い、×：大変悪い 悪
【００９４】
（環境変動評価）
環境安定性は、１０℃、２０％の低温低湿環境と３０℃、８０％の高温高湿環境での帯電量を、ブローオフ法によって求め、その時の値を下記式に代入し、環境変動率を算出後、次の判定基準により５段階に評価した。
環境変動率（％）＝（（低温低湿帯電量−高温高湿帯電量）／低温低湿帯電量）×１００
良 ◎：５０％未満、○：５０〜６０％、□：６０〜７０％、△：７０〜８０％、×：８０％以上 悪
【００９５】
（耐熱保存性評価）
トナー試料２０ｇを２０ｍｌのガラス瓶に入れ、６０℃の高温槽に４時間放置し、その後針入度試験（ＪＩＳ Ｋ２２３５−１９９１）にて針入度を次の基準により評価した。
良 ◎：１０ｍｍ以上、○：９．９〜５ｍｍ、△：４．９〜３ｍｍ、×：２．９〜０ｍｍ 悪
【００９６】
（細線再現性）
（株）リコー製複写機 ＭＦ−２００を用いて、画像評価テストを行い、細線再現性の評価を行った。評価は、次の判断基準により５段階で行った。
◎：大変良い、○：良い、□：普通、△：悪い、×：大変悪い
【００９７】
（トナー着色力）
（株）リコー製複写機 ＭＦ−２００にてトナー付着量０．５ｍｇ／ｃｍ^２、１．０ｍｇ／ｃｍ^２の画像を作製し画像濃度をマクベス濃度計により測定した。画像濃度が高いほど着色力は大きい。
【００９８】
（トナー飛散）
（株）リコー製複写機 ＭＦ−２００にて１００，０００枚のコピーを行いマシン前扉内側に添付した白紙の汚れをマクベス濃度計にて測定した。白紙のマクベス濃度は０．０７であり、この値が高いほどトナー飛散が悪い。
【００９９】
（画像濃度、地汚れ）
（株）リコー製複写機 ＭＦ−２００にて１００，０００枚のコピーを行いスタート、５０，０００枚、１００，０００枚時の画像濃度、地汚れをマクベス濃度計にて測定した。
【０１００】
【表２】

【０１０１】
【表３】

【０１０２】
【発明の効果】
以上のように、請求項１の静電荷像現像用トナーによれば、樹脂成分が非線状ポリマー樹脂（Ａ）、線状ポリマー樹脂（Ｂ）と同種のポリマーユニットを含むハイブリッド樹脂（Ｃ）を加え、さらに着色剤としてチタン成分をＴｉ原子換算でＦｅ原子に対して１０〜４５重量％含有する黒色酸化鉄化合物を用いることから、非線状ポリマーと線状ポリマーが適度に相溶し、高画質で低温定着性と耐ホットオフセット性を両立させ、さらに熱保存性、生産性、かぶりのない良好な画像を形成することができる。
【０１０３】
請求項２の静電荷像現像用トナーによれば、上記トナーの飽和磁化σｓが０．５〜３０ｅｍｕ／ｇであることから、感光体への現像性が悪化することがなく、またトナー飛散や、地汚れも悪化しない。
【０１０４】
請求項３の静電荷像現像用トナーによれば、上記黒色酸化鉄化合物の平均一次粒径が０．０５〜２．０μｍであることから、トナー中での分散性が非常に優れている。
【０１０５】
請求項４の静電荷像現像用トナーによれば、上記樹脂（Ａ）、（Ｂ）、（Ｃ）が全て少なくともポリエステルユニットを含むことから、非線状ポリマーと線状ポリマーを適度に相溶させることができ、粉砕性と耐熱保存性を損なうことなく幅広い定着可能温度幅とかぶりなどの画像品質を満足するトナーを得ることができる。
【０１０６】
請求項５の静電荷像現像用トナーによれば、上記樹脂（Ａ）、（Ｂ）、（Ｃ）が全て少なくともポリアミドユニットを含むことから、非線状ポリマーと線状ポリマーを適度に相溶させることができ、粉砕性と耐熱保存性を損なうことなく幅広い定着可能温度幅とかぶりなどの画像品質を満足するトナーを得ることができる。
【０１０７】
請求項６の静電荷像現像用トナーによれば、上記樹脂（Ａ）、（Ｂ）、（Ｃ）の軟化点（Ｔｍ）及びガラス転移点（Ｔｇ）が式（Ｉ）〜（ＩＩＩ）を満足することから、かぶりに改善効果が有り、また、トナー混練時に相溶性が悪くならず、低温定着性とホットオフセット性の両立ができ、十分な定着可能温度領域を保つことが出来る。
【０１０８】
請求項７の静電荷像現像用トナーによれば、上記トナーの体積平均粒径が４〜７．５μｍで、かつ、５μｍ以下の粒子が６０〜８０個数％含有していることから、細線再現性に優れ、また、転写効率の低下やブレードクリーニング性の低下などがない。
【０１０９】
請求項８の静電荷像現像用トナーによれば、ワックス成分として０．５〜２０重量％のカルナウバワックス、ライスワックス及びエステルワックスの少なくとも一つを含有することから、結着樹脂中に均一分散が可能である。
【０１１０】
請求項９のプロセスカートリッジによれば、上記本発明のトナーを用いることから、画質の優れたプロセスカートリッジを提供することができる。
【０１１１】
請求項１０の画像形成装置によれば、上記本発明のトナーを用いることから、画質の優れた接触帯電装置を有する画像形成装置を提供することができる。
【図面の簡単な説明】
【図１】プロセスカートリッジの一例を示す概略構成図。
【図２】接触帯電の帯電特性を示すグラフ。
【図３】ローラ帯電による接触帯電装置の一例を示す概略構成図。
【図４】ブラシ帯電による接触帯電装置の一例を示す概略構成図
【符号の説明】
１ プロセスカートリッジ全体
２ 感光体
３ 帯電手段
４ 現像手段
５ クリーニング手段
１０ 感光体ドラム
１１ 帯電ローラ
１２ 芯金
１３ 導電ゴム層
１４ 電源
２０ 感光体
２１ ファーブラシローラまたは磁気ブラシローラ
２２ 芯金
２３ ブラシ部
２４ 電源[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming toner used for developing an electrostatic latent image such as an electrophotographic method, an electrostatic recording method, and an electrostatic printing method.
[0002]
[Prior art]
Conventionally, as an electrophotographic method, various methods have been described in US Pat. No. 2,297,691, Japanese Patent Publication No. 49-23910, Japanese Patent Publication No. 43-24748, etc. The latent image is used to form an electric latent image on the photoreceptor by various means, and then the latent image is developed with toner. If necessary, the toner powder image is transferred to paper or the like, and then heated and pressed. Alternatively, it is fixed by solvent vapor or the like to obtain a copy image.
[0003]
Methods for developing electrical latent images can be broadly divided into a liquid development method using a developer in which various pigments and dyes are finely dispersed in an insulating organic liquid, a cascade method, a magnetic brush method, and a powder cloud method. As described above, there is a dry development method using a toner in which a colorant such as carbon black is dispersed in a natural or synthetic resin, and the dry development method has been widely used in recent years because of its easy handling.
[0004]
As a fixing method in electrophotography, a heated heat roller method is widely used because of its energy efficiency. Further, in recent years, the thermal energy given to the toner at the time of fixing tends to be small like low-temperature fixing and high-speed copying for energy saving. In particular, in order to save energy, the standby time is strongly shortened in order to minimize the power required for the waiting time (image warm-up time) from when the image forming device is switched on until image formation is possible. It is requested.
[0005]
The 1999 International Energy Agency (IEA) DSM (Demand-side Management) program includes a technology procurement project for next-generation copiers, the requirements for which were published, and for copiers of 30 cpm and above, It is required to achieve dramatic energy saving compared to conventional copying machines so that the standby time is within 10 seconds and the standby power consumption is 10 to 30 watts or less (differs depending on the copying speed).
[0006]
One way to achieve this requirement is to reduce the heat capacity of a fixing member such as a heated heat roller to improve the temperature responsiveness of the toner, but it is not fully satisfactory. In order to achieve the above requirement and minimize the waiting time, it is considered that a reduction in the fixing temperature of the toner itself is an essential technical achievement item.
[0007]
However, when this low-temperature fixing level is compared with the set temperature of the image forming apparatus, a lower set temperature is required than when the conventional low-temperature fixing toner is used, and it can be easily achieved even by applying a conventionally known technique. Is impossible.
Further, when the toner is fixed at a low temperature in this way, there is a problem that it becomes difficult to secure a fixing temperature range (hot offset resistance) and maintain heat storage stability.
[0008]
In recent years, the demand for high-quality images has increased in the market, and conventional toners having a volume average diameter of 10 to 15 μm have become unable to obtain sufficient image quality. It has been. However, as the particle size of the toner progresses, various problems occur in areas other than the image. In particular, in the fixing process, the amount of toner attached to a fixing material such as paper in the halftone portion decreases. As a result, the amount of heat applied from the heating member to the toner transferred to the concave portion of the fixing material becomes extremely small, and therefore, there is a drawback that an offset reduction phenomenon is likely to occur.
[0009]
In general, attempts have been made to improve the low-temperature fixability of the toner used for such low-temperature fixing by using a resin or wax having a low softening point. However, such a low-temperature fixing toner is known to cause so-called blocking because it is thermally weak and hardens due to the heat of the machine being used or heat during storage. In addition, it is difficult to secure a sufficient fixing temperature range, and even if a polyester resin, which is said to have relatively good heat storage for good low-temperature fixability, a toner that still solves this problem can be obtained. Not.
[0010]
In order to solve these problems, several methods using two types of polyester resins having different characteristics have been proposed. For example, a method of mixing a non-linear polyester resin and a linear polyester resin (Japanese Patent Laid-Open No. 60-90344), a crosslinked polyester resin having a Tg of 50 ° C. or more and a softening point of 200 ° C. or less and a softening point of 150 ° C. or less MW 3,000 to Method of mixing 50,000 linear polyester resin (Japanese Patent Laid-Open No. 64-15755), MW 5,000 or more, non-linear polymer polyester resin having a dispersion ratio of 20 or more and MW 1,000 to 5,000, dispersion A method of containing a non-linear polyester resin having a ratio of 4 or less (JP-A-2-82267), an organometallic compound comprising a linear polyester resin having an acid value of 5 to 60 and a non-linear polyester resin having an acid value of less than 5 Method of containing (Japanese Patent Laid-Open No. 3-229264), saturated polyester resin and different polyester resins having an acid value ratio of 1.5 or more Mixing method for it is (JP-A-3-41470 JP) or the like.
[0011]
JP-A-49-6931, JP-A-54-114245, etc. show a system in which a polyester resin having excellent fixability is mixed with a styrene acrylic resin having excellent grindability. Since the resin is inherently poor in compatibility, simply mechanically mixing makes it non-uniform, resulting in poor dispersion of carbon and the charge control agent at the time of toner formation, and there are problems such as fogging.
[0012]
Therefore, by a method using a resin obtained by polymerizing a polyester resin and a styrene resin in the same container (Japanese Patent Laid-Open No. 4-142301, Japanese Patent No. 3210176, Japanese Patent No. 3219230). The above drawbacks are solved.
[0013]
Further, in recent years, attempts have been made to use black metal compound fine powder that has high safety and good thermal conductivity as a colorant that changes to carbon black. For example, in Japanese Patent No. 2736680, a mixture of Fe ₂ TiO ₅ and Fe ₂ O ₃ —FeTiO ₃ solid solution having an average particle size of 0.1 to 0.5 μm is disclosed in Japanese Patent No. 3101882, Japanese Patent No. 3108823, In Japanese Patent No. 3174960, magnetic iron oxide containing 25-30% FeO is used. In Japanese Patent No. 3224774 and Japanese Patent No. 3261888, magnetite having a remanent magnetization of 6 emu / g or less is disclosed in Japanese Patent Laid-Open No. 2000-319021. On the surface of Ti, iron oxide particles composed of Ti and Fe were coated with a saturation magnetization of 0.5 to 10 emu / g, a particle size of 0.1 to 0.4 μm, and Fe ₂ TiO ₄ in JP 2002-129063. A rutile TiO ₂ mixed phase crystal has a saturation magnetization of 30 emu / g or less and a dielectric loss factor of 5 in Japanese Patent Application Laid-Open No. 2002-189313. Japanese Patent Application Laid-Open No. 2002-196528 discloses a metal compound having a saturation magnetization of 40 emu / g or less and a content of 20 parts by weight or less.
[0014]
However, in recent years, low-temperature fixing has become increasingly advanced, coupled with downsizing of the device, ensuring a fixing temperature range that achieves both low-temperature fixing properties and hot offset properties, especially when using a low-load fixing device, and thermal storage stability. However, it is required to satisfy image quality such as pulverization and fogging, but the level has not been reached.
[0015]
[Patent Document 1]
Japanese Patent No. 2736680 [Patent Document 2]
Japanese Patent No. 3101782 [Patent Document 3]
Japanese Patent No. 3108823 [Patent Document 4]
Japanese Patent No. 3174960 [Patent Document 5]
Japanese Patent No. 3224774 [Patent Document 6]
Japanese Patent No. 3261888 [Patent Document 7]
JP 2000-319021 A [Patent Document 8]
JP 2002-129063 A [Patent Document 9]
JP 2002-189313 A [Patent Document 10]
JP 2002-196528 A [0016]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and is a toner that can achieve high image quality, low-temperature fixability and hot offset resistance, and can form a good image without thermal storage, productivity, and fog. Another object of the present invention is to provide an image forming apparatus having a process cartridge using the toner and excellent in image quality and a contact charging device. Furthermore, a new black colorant that replaces carbon black is provided.
[0017]
The object of the present invention is achieved by the following means.
<1> In an electrostatic charge developing toner containing a resin component, a wax component, and a colorant as essential components, the saturation magnetization σs of the toner is 17.5 to 30 emu / g, and the resin component is a non-linear polymer resin ( A) Using a mixture containing the linear polymer resin (B) and the raw material monomer of the polycondensation resin and the raw material monomer of the addition polymerization resin, the polycondensation reaction and the addition polymerization reaction are performed in parallel in the same reaction vessel. And (A), (B), (C) is a resin containing at least the same type of polymer unit, and as the colorant, the titanium component is converted to Fe atom in terms of Ti atom. A toner for developing an electrostatic charge image, comprising using a black iron oxide compound containing 10 to 45% by weight based on the weight of the toner.
<2> The toner for developing an electrostatic charge image according to <1>, wherein the black iron oxide compound has an average primary particle size of 0.05 to 2.0 μm.
<3> The electrostatic image developing toner according to any one of <1> to <2>, wherein the resins (A), (B), and (C) all include at least a polyester unit.
<4> From the above <1> to <3>, the softening point (Tm) and glass transition point (Tg) of the resins (A), (B), and (C) satisfy the following formulas (I) to (III): The toner for developing an electrostatic image according to any one of the above.
[Expression 1]

<5> The electrostatic charge image development according to any one of <1> to <4>, wherein the toner has a volume average particle diameter of 4 to 7.5 μm and contains 60 to 80% by number of particles of 5 μm or less. Toner.
<6> The electrostatic charge image developing toner according to any one of <1> to <5>, wherein 0.5 to 20% by weight of carnauba wax is contained as a wax component.
<7> In a process cartridge that integrally supports at least one member selected from a photosensitive member, a charging unit, a developing unit, and a cleaning unit, and is detachably provided in the main body of the image forming apparatus, the developing unit includes a toner ( A process cartridge, wherein the toner (developer) is a toner for developing an electrostatic image according to any one of <1> to <6>.
<8> A toner (developer) to be used that has at least a charging device, and the charging device contacts the latent image carrier with a charging member and applies a voltage to the charging member. Is an electrostatic charge image developing toner according to any one of <1> to <6>.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The toner of the present invention is an electrostatic charge developing toner containing a resin component, a wax component, and a colorant as essential components, and the toner has a saturation magnetization σs of 17.5 to 30 emu / g, and the resin component is non- Using a mixture containing a linear polymer resin (A), a linear polymer resin (B), a raw material monomer of a condensation polymerization resin and a raw material monomer of an addition polymerization resin, a condensation polymerization reaction and an addition polymerization reaction in the same reaction vessel (A), (B), and (C) are binder resins containing at least the same kind of polymer units, and a titanium component is used as the colorant. A black iron oxide compound containing 10 to 45% by weight of Fe atoms in terms of Ti atoms is used.
[0029]
The structure of the black iron oxide compound is preferably a polycrystalline particle powder containing a Fe ₂ O ₃ —FeTiO ₃ solid solution because it is black and has a weak magnetism.
[0030]
The black iron oxide compound according to the present invention is obtained by reducing, for example, magnetite particle powder whose particle surface is coated with a titanium compound, mixed powder of magnetite particle powder and titanium compound, or hematite particle powder whose particle surface is coated with a titanium compound. Each of the obtained reduced powders is obtained by a method of heating and firing at a temperature of 700 ° C. or higher in a non-oxidizing atmosphere and then pulverizing. When magnetite particle powder having a particle surface coated with a titanium compound is used as a raw material, it is a preferable method from the viewpoint of easily obtaining particles having a small magnetization value and non-magnetism.
[0031]
The magnetite particle powder and the hematite particle powder may be particles in any form such as granular, spherical, and needle-like, and particles having a size of about 0.03 to 1.5 μm can be used.
[0032]
There is a correlation between the size of the raw material particles and the size of the product particles. When small-sized raw material particles are used, small-sized product particles tend to be obtained. When large-sized raw material particles are used, large-sized product particles tend to be obtained. It is in.
[0033]
As the titanium compound, any of hydrated oxide, hydroxide and oxide of titanium can be used. When mixing with magnetite particle powder, it is preferable to use a water-soluble titanium compound. The amount of the titanium compound is preferably in the range of 10 to 45 wt. When the amount is less than 10% by weight, the magnetization value of the obtained black pigment particle powder is increased, the developing ability of the toner is lowered, and the image density is lowered. If it exceeds 45% by weight, non-magnetic black pigment particle powder can be obtained. However, since the amount of TiO ₂ produced increases, the L value (lightness) increases and the toner coloring power decreases.
[0034]
The ratio with respect to Fe atoms in terms of Ti atoms can be determined from the ratio of the obtained main peak using a fluorescent X-ray analyzer.
[0035]
The content of the black iron oxide compound is 5 to 45 parts by weight, preferably 10 to 30 parts by weight. When the amount is less than 5 parts by weight, the coloring power of the toner becomes insufficient, and the toner has a reddish color. Further, the fixing temperature is not sufficiently lowered. When the amount exceeds 45 parts by weight, the specific gravity of the toner becomes too large and the developing ability is lowered.
[0036]
In the present invention, the saturation magnetization σs of the toner is preferably 0.5 to 30 emu / g. When the saturation magnetization of the toner exceeds 30 emu / g, the holding force with the toner carrier having a built-in magnet such as a magnetic sleeve and a magnetic brush becomes strong, and the developability to the photoreceptor deteriorates. When it is less than 0.5 emu / g, the holding force with the toner carrier is weakened, and the toner scattering and the soiling are worsened.
The saturation magnetization of the toner is measured from a hysteresis curve when a magnetic field is swept up to 10 kOe in a toner filled in a cell having an inner diameter of 7 mmφ and a height of 10 mm by using a magnetometer BHU-60 manufactured by Riken Denshi Co., Ltd. Magnetization was determined.
[0037]
In the present invention, the average primary particle size of the black iron oxide compound contained in the toner is preferably 0.05 to 2.0 μm, and particularly preferably in the range of 0.1 to 0.5 μm from the viewpoint of dispersibility in the toner. .
The average primary particle diameter of the black iron oxide compound was shown as an average value of numerical values measured from an electron micrograph taken with a Hitachi transmission electron microscope H-9000.
[0038]
Regarding the characteristics of the resin, as a toner low-temperature fixing for achieving energy savings more than ever, a linear polymer (B) having a low-temperature fixability and a non-linear polymer (A) having a hot offset resistance, By using the same kind of polymer in (A) and (B), it was possible to increase the dispersibility of the resin and widen the fixable temperature range. However, when only a conventional polymer resin with high low-temperature fixability is mixed and used, the resin is soft and the compatibility of the polymer itself is good, so the resin is difficult to break and the productivity is deteriorated. Sex was also insufficient.
[0039]
Therefore, in the present invention, by adding a hybrid resin (C) containing a polymer unit of the same type as (A) and (B), the non-linear polymer and the linear polymer are appropriately compatible with each other. It has been found that a toner that satisfies a wide range of fixable temperature ranges and image quality such as fogging can be provided without impairing storage stability. When the polymer units of (A), (B), and (C) were different, the difference in compatibility between them became large, the dispersion of carbon and the charge control agent became poor, and the problem of fogging occurred.
[0040]
In particular, when the softening point (Tm) and glass transition point (Tg) of the polymer (A), the polymer (B) and the hybrid resin (C) satisfy the following formulas (I) to (III), further fixing It was possible to increase the possible temperature range and grindability.
[0041]
[Equation 3]
Tm (A)> Tm (C)> Tm (B) (I)
| Tg (A) -Tg (B) | <10 (° C.) (II)
30 ≦ Tm (A) −Tm (B) ≦ 60 (° C.) (III)
By satisfying Tm (A)> Tm (C)> Tm (B), the fog had an improvement effect. This is considered because the hybrid resin (C) disperses the polymer (A) and the polymer (B) well. Further, when Tg (A) -Tg (B) was 10 ° C. or higher, the compatibility was deteriorated during toner kneading, and it was difficult to achieve both low-temperature fixability and hot offset property. More preferably, it is 7 degrees C or less. Further, by setting Tm (A) -Tm (B) to 30 ° C. to 60 ° C., both low temperature fixability and hot offset property can be achieved, and a sufficient fixable temperature range can be maintained. More preferably, it is 35-55 degreeC.
[0042]
Further, when the toner volume average particle diameter was 4 to 7.5 μm and the particles having a particle size of 5 μm or less had a particle size distribution of 60 to 80% by number, the fine line reproducibility was excellent.
When the volume average particle size is less than 4 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur. When the volume average particle diameter exceeds 7.5 μm, it is difficult to suppress scattering of characters and lines.
If the particle size is 5% or less, the reproducibility of fine lines is deteriorated. When the particle size of 5 μm or less exceeds 80%, there are too many fine powders, and fixing of the developing sleeve is deteriorated.
[0043]
Next, a method for measuring the particle size distribution of toner particles will be described.
Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as the aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.
[0044]
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.
[0045]
In the present invention, it is preferable to contain at least one of carnauba wax, rice wax and ester wax as a wax component.
Carnauba wax is a natural wax obtained from the leaves of carnauba palm, and a low acid value type from which free fatty acids are eliminated is particularly preferable because it can be uniformly dispersed in the binder resin.
Rice wax is a natural wax obtained by refining crude wax produced in a dewaxing or wintering process when refining rice bran oil extracted from rice bran. Ester wax is synthesized by ester reaction from monofunctional linear fatty acid and monofunctional linear alcohol.
These wax components are used alone or in combination. The addition amount of the wax component is 0.5 to 20 parts by weight, more preferably 2 to 10 parts by weight.
In the present invention, other wax components of carnauba wax, rice wax, and synthetic ester wax can be used. For example, polyolefin wax such as polypropylene wax and polyethylene wax.
[0046]
Next, materials used for the toner of the present invention will be described in detail.
As the polymer resin used in the present invention, any polymer resin obtained by a condensation polymerization reaction such as polyester, polyamide, polyester / polyamide resin, or any other polymer resin obtained by an addition polymerization reaction such as styrene acrylic or styrene butadiene can be used. . Further, there is no limitation as long as it is a polymer obtained by condensation polymerization reaction or addition polymerization reaction.
[0047]
The polyester resin used in the present invention is a polymer obtained by polycondensation of a polyvalent hydroxy compound and a polybasic acid. Examples of the polyvalent hydroxy compound include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol, alicyclic compounds containing two hydroxyl groups such as 1,4-bis (hydroxymethyl) cyclohexane, and bisphenol A. And the like, and the like. The polyvalent hydroxy compounds include those containing 3 or more hydroxyl groups.
[0048]
Examples of the polybasic acid include divalent carboxylic acids such as maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and malonic acid, 1,2,4-benzenetricarboxylic acid, 5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1 , 2,7,8-octanetetracarboxylic acid and other trivalent or higher polyvalent carboxylic acid monomers.
[0049]
As the raw material monomer for polyester / polyamide and polyamide, in addition to the above monomer raw materials, examples of the monomer for forming the amide component include, for example, polyamines such as ethylenediamine, pentamethylenediamine, hexamethylenediamine, phenylenediamine, triethylenetetramine, and 6-aminocaprone. Examples thereof include amino acids such as acids and ε-caprolactam. Here, the glass transition temperature Tg of the resin is preferably 55 ° C. or more, more preferably 57 ° C. or more, from the viewpoint of heat storage stability.
[0050]
The polymer resin obtained by the addition polymerization reaction is typically a vinyl resin by radical polymerization, but is not particularly limited. Examples of the raw material monomer for addition polymerization resins include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-ethyl styrene, vinyl naphthalene, such as ethylene, propylene, butylene, isobutylene, etc. Ethylenically unsaturated monoolefins such as vinyl esters such as vinyl chloride, vinyl bromide, vinyl acetate, vinyl formate, such as acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, Tert-butyl acrylate, amyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, tert-butyl methacrylate, amyl methacrylate, stearyl methacrylate, methacrylic acid Ethylenic monocarboxylic acids such as methoxyethyl, glycidyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and esters thereof, for example, ethylenic monocarboxylic acid substitution products such as acrylonitrile, methacrylonitrile, acrylamide, Examples thereof include ethylenic dicarboxylic acids such as dimethyl maleate and substituted products thereof, for example, vinyl ketones such as vinyl methyl ketone. Moreover, a crosslinking agent can be added as needed. As a crosslinking agent for addition polymerization monomers, for example, divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, diallyl phthalate, etc. A cross-linking agent can be used.
[0051]
The amount of these crosslinking agents used is 0.05 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts of the raw material monomer of the addition polymerization resin. When the amount is less than 0.05 parts by weight, there is no effect of the crosslinking agent. When the amount exceeds 15 parts by weight, melting by heat becomes difficult, and the toner becomes poorly fixed when fixing using heat.
[0052]
In addition, a polymerization initiator is used when the raw material monomer of the addition polymerization resin is polymerized. For example, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, other azo or diazo polymerization initiators, or benzoyl peroxide, methyl ethyl ketone peroxide And peroxide polymerization initiators such as 2,4-dichlorobenzoyl peroxide. These may be used by mixing two or more kinds of polymerization initiators for the purpose of adjusting the molecular weight and molecular weight distribution of the polymer. The amount of the polymerization initiator used is 0.05 to 15 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts of the raw material monomer of the addition polymerization resin.
[0053]
In these polycondensation reactions or addition polymerization reactions, the resulting polymer resin may be a polymer having a non-linear structure or a polymer having a linear structure, depending on differences in reaction raw materials and the like. In the present invention, both the non-linear polymer resin (A) and the linear polymer resin (B) are used.
In the present invention, the non-linear polymer resin means a polymer resin having a substantially crosslinked structure, and the linear polymer resin means a polymer resin having substantially no crosslinked structure.
[0054]
In the present invention, in order to obtain a hybrid resin in which a condensation polymerization resin and an addition polymerization resin are chemically bonded, it is preferable to perform polymerization using a compound that can react with any of the monomers of both resins. Examples of such a bireactive monomer include compounds such as fumaric acid, acrylic acid, methacrylic acid, maleic acid, and dimethyl fumarate.
The amount of the both reactive monomers used is 1 to 25 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts of the raw material monomer of the addition polymerization resin. When the amount was less than 1 part by weight, the colorant and the charge control agent were poorly dispersed and the image quality such as fog was deteriorated. When the amount is more than 25 parts by weight, there is a problem that the resin is gelled.
[0055]
The hybrid resin as described above does not need to proceed and complete both reactions at the same time, and can select each reaction temperature and time to complete the reaction independently. For example, in a reaction vessel, a mixture of a polyester resin polycondensation raw material monomer is dropped in advance and a mixture of a vinyl resin addition polymerization raw material monomer and a polymerization initiator is mixed in advance. There is a method in which a polymerization reaction comprising a polyester resin is completed by a condensation polymerization reaction by completing the polymerization reaction comprising, and then raising the reaction temperature. By this method, it is possible to effectively disperse the two kinds of resins by allowing two independent reactions to proceed in parallel in the reaction vessel.
[0056]
In the present invention, as the resin component in the toner, a resin other than the above-mentioned resins can be used in combination as long as the performance of the toner is not impaired. Examples of usable resins in this case include the following, but are not limited thereto. Polyurethane resin, silicone resin, ketone resin, petroleum resin, hydrogenated petroleum resin. These resins are not limited to single use but can be used in combination of two or more. Also, these production methods are not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used.
[0057]
In the toner of the present invention, polarity control can be blended in order to control polarity. Examples of the polarity control agent in this case include nigrosine dyes, quaternary ammonium salts, amino group-containing polymers, metal-containing azo dyes, salicylic acid complex compounds, and phenol compounds.
[0058]
The toner production method of the present invention may be a conventionally known method, in which a resin component, a colorant, a wax component, and other cases, a charge control agent or the like are mixed using a mixer or the like, and kneaded such as a heat roll or an extruder. After kneading using a machine, the mixture is cooled and solidified, and this is pulverized by a pulverizer such as a jet mill and then classified.
[0059]
Other additives may be added to the toner as necessary. Examples of the additive include silica, aluminum oxides, and titanium oxides. When the main purpose is to impart high fluidity, the average primary particle diameter of the hydrophobized silica or rutile type fine particle titanium oxide is suitably 0.001 to 1 μm, preferably 0.005 to 0.1 μm. In particular, organosilane surface-treated silica or titania is preferable, and is usually used in a proportion of 0.1 to 5% by weight, preferably 0.2 to 2% by weight.
[0060]
Further, for example, when the toner of the present invention is used as a two-component dry toner, the carrier used by mixing is mainly composed of glass, iron, ferrite, nickel, zircon, silica, etc., and has a particle size of 30 to 1000 μm. It is possible to appropriately select and use a powder of a certain degree, or a powder coated with a styrene-acrylic resin, a silicone resin, a polyamide resin, a polyvinylidene fluoride resin or the like using the powder as a core material.
[0061]
Even when the toner of the present invention is loaded into an image forming apparatus having a process cartridge to form an image, an excellent effect can be obtained. That is, by using the toner of the present invention, a process cartridge with excellent image quality can be provided.
[0062]
FIG. 1 shows an example of a schematic configuration of a process cartridge. 1 denotes an entire process cartridge, 2 denotes a photosensitive member, 3 denotes a charging unit, 4 denotes a developing unit, and 5 denotes a cleaning unit.
[0063]
In an image forming apparatus having a process cartridge, a photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member 2 is uniformly charged with a positive or negative predetermined potential on the peripheral surface thereof by the charging unit 3, and then receives image exposure light from an image exposure unit such as slit exposure or laser beam scanning exposure. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photosensitive member 2, and the formed electrostatic latent image is then developed with toner by the developing unit 4, and the developed toner image is transferred from the paper feeding unit to the photosensitive member. The image is sequentially transferred by the transfer means onto the transfer material fed in synchronism with the rotation of the photosensitive member. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoreceptor after the image transfer is cleaned by the cleaning means 5 to remove the transfer residual toner, and after further static elimination, it is repeatedly used for image formation.
[0064]
Furthermore, when the toner of the present invention is used in an image forming apparatus having a contact type charging device, an excellent effect can be obtained. That is, by using the toner of the present invention, an image forming apparatus that employs a charging device with reduced ozone can be provided.
[0065]
FIG. 3 shows a schematic configuration of an example of an image forming apparatus using a charging device that performs roller charging. The photosensitive member 10 serving as a member to be charged and an image carrier is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. The charging roller 11 as a charging member brought into contact with the photosensitive drum 10 is basically composed of a cored bar 12 and a conductive rubber layer 13 formed concentrically on the outer periphery of the cored bar 12 on both ends of the cored bar 12. In addition to being held freely rotating by a bearing member (not shown), the photosensitive drum is pressed with a predetermined pressure by a pressing means (not shown). In the case of FIG. Rotates following the rotational drive. The charging roller 11 is formed to have a diameter of 16 mm by coating a medium resistance rubber layer of about 100,000 Ω · cm on a core metal having a diameter of 9 mm.
The cored bar 12 of the charging roller 11 and the illustrated power source 14 are electrically connected, and a predetermined bias is applied to the charging roller 11 by the power source 14. As a result, the peripheral surface of the photoconductor 10 is uniformly charged to a predetermined polarity and potential.
[0066]
FIG. 4 shows a schematic configuration of an example of an image forming apparatus using a charging device that performs brush charging. The photosensitive member 20 as the charged body and the image carrier is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. A brush roller 21 composed of a fur brush or a magnetic brush is brought into contact with the photoreceptor 20 with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion 23.
[0067]
The fur brush roller 21 as a contact charging member in this example is made of a metal cored bar 22 having a diameter of 6 mm which also serves as an electrode, and a conductive rayon fiber REC-B manufactured by Unitika Co., Ltd. as a brush portion 23 in a pile. A tape is wound in a spiral shape to form a roll brush having an outer diameter of 14 mm and a longitudinal length of 250 mm. The brush of the brush portion 23 has a density of 300 denier / 50 filaments and 155 per square millimeter. This roll brush was inserted into a pipe having an inner diameter of 12 mm while rotating in one direction, and the brush and the pipe were set to be concentric, and left in a high-temperature and high-humidity atmosphere to bend and bevel.
The resistance value of the fur brush roller 21 is 1 × 10 ⁵ Ω at an applied voltage of 100V. This resistance value was converted from the current that flows when the fur brush roller 21 is brought into contact with a metal drum 30 mm in diameter with a nip width of 3 mm and a voltage of 100 V is applied.
[0068]
The resistance value of the fur brush charger is such that, even when a low-voltage defective portion such as a pinhole is generated on the photosensitive member 20 as a charged member, an excessive leakage current flows into this portion, and the charging nip portion becomes poorly charged. 10 ⁴ Ω or more is necessary to prevent image defects, and 10 ⁷ Ω or less is necessary to sufficiently inject charges onto the surface of the photoreceptor.
In addition to REC-B manufactured by Unitika Ltd., the brush material is REC-C, REC-M1, REC-M10, SA-7 manufactured by Toray Industries, Inc., Nippon Kashiwa Co., Ltd. It is possible to use Sanderlon manufactured by Kanebo, Beltron manufactured by Kanebo, Kuraray Co., Ltd., Krabobo, carbon dispersed in rayon, Mitsubishi Rayon Co., Ltd. global, etc. One brush is 3 to 10 denier, and preferably has a density of 10 to 100 filaments / bundle and 80 to 600 brushes / mm. The hair foot is preferably 1 to 10 mm.
[0069]
The fur brush roller 21 is rotationally driven at a predetermined peripheral speed (surface speed) in a direction (counter) opposite to the rotation direction of the photoconductor 20, and contacts the photoconductor surface with a speed difference. Then, a predetermined charging voltage is applied to the fur brush roller 21 from the power supply 24, so that the surface of the rotating photosensitive member is uniformly contact-charged to a predetermined polarity and potential.
In this example, contact charging of the photoconductor 20 by the fur brush roller 21 is performed by direct injection charging, and the surface of the rotating photoconductor is charged to a potential substantially equal to the charging voltage applied to the fur brush roller 21.
[0070]
In the case of magnetic brush charging, as in the case of the fur brush charging described above, the brush roller 21 constituted by a magnetic brush with respect to the photosensitive member has a predetermined pressing force against the elasticity of the brush portion 23 with a predetermined nip width. Make contact.
As the magnetic brush as the contact charging member, Zn—Cu ferrite particles having an average particle diameter of 25 μm and Zn—Cu ferrite particles having an average particle diameter of 10 μm are mixed at a weight ratio of 1: 0.05, and the respective averages are mixed. Magnetic particles obtained by coating ferrite particles having an average particle diameter of 25 μm having a peak at the position of the particle diameter with a medium resistance resin layer were used. The contact charging member is composed of the coated magnetic particles produced as described above, a nonmagnetic conductive sleeve for supporting the coated magnetic particles, and a magnet roll included therein, and the coated magnetic particles are formed on the sleeve with a thickness. Coating was performed at 1 mm to form a charging nip having a width of about 5 mm between the photosensitive member and the photosensitive member. The gap between the magnetic particle holding sleeve and the photosensitive member was about 500 μm. Further, the magnet roll is rotated so that the sleeve surface rubs in the opposite direction at twice as fast as the circumferential speed of the surface of the photoconductor, and the photoconductor and the magnetic brush are in uniform contact with each other. I did it.
[0071]
【Example】
Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. In the examples, all parts represent parts by weight.
[0072]
First, an example of resin production is shown.
Production of Non-Linear Polyester Resin Fumaric Acid: 10 mol, Trimellitic Anhydride: 4 mol, Bisphenol A (2,2) Propylene Oxide: 6 mol, Bisphenol A (2,2) Ethylene Oxide: 4 mol Stainless Stir Bar, Flowing Capacitor Then, it was placed in a flask equipped with a nitrogen gas introduction tube and a thermometer, and a polycondensation reaction was performed while stirring at a temperature of 220 ° C. in a nitrogen atmosphere to obtain a non-linear polyester resin.
[0073]
Production of linear polyester resin: terephthalic acid: 8 mol, trimellitic anhydride: 3 mol, bisphenol A (2,2) propylene oxide: 6 mol, bisphenol A (2,2) ethylene oxide: 4 mol of stainless steel stirring rod, flow-down condenser, A linear polyester resin was obtained by placing in a flask equipped with a nitrogen gas inlet tube and a thermometer and performing a condensation polymerization reaction with stirring at a temperature of 220 ° C. in a nitrogen atmosphere.
[0074]
Manufacture of hybrid resin 20 mol of styrene as an addition polymerization reaction monomer, 5 mol of butyl methacrylate, 0.4 mol of t-butyl hydroperoxide as a polymerization initiator are placed in a dropping funnel, and fumaric acid: 10 mol as an addition polymerization and polycondensation reactive monomer. Trimellitic anhydride: 4 mol as a condensation polymerization monomer, 6 mol of bisphenol A (2,2) propylene oxide: 4 mol, 4 mol of bisphenol A (2,2) ethylene oxide, 60 mol of dibutyltin oxide as an esterification catalyst The mixture was placed in a flask equipped with a condenser, a nitrogen gas inlet tube and a thermometer, and a mixture prepared by adding an addition polymerization material in advance from a dropping funnel was dropped over 5 hours while stirring at 135 ° C. in a nitrogen atmosphere. After completion, the mixture was aged for 6 hours while keeping at 135 ° C., and then reacted by raising the temperature to 220 ° C. to obtain a hybrid resin.
[0075]
The polymerization degree of the polymer is traced from the softening point in accordance with ASTM E28-67, and when the predetermined softening point is reached, the reaction is terminated, extracted from the container, cooled and pulverized, and the characteristic values shown in Table 1 are obtained. A possessed polymer was obtained.
Table 1 shows physical property values of the polyester resins used in Examples 1 to 9 and Comparative Examples 1 to 4.
[0076]
[Table 1]

[0077]
The softening temperature was performed according to the method described in JIS K72101 using a Koka type flow tester (manufactured by Shimadzu Corporation). While heating a sample of 1 cm ^{3 at} a heating rate of 6 ° C./min, a load of 20 Kg / cm ² was applied by a plunger to push out a nozzle having a diameter of 1 mm and a length of 1 mm. When a temperature curve is drawn and the height of the S-shaped curve is h, the temperature corresponding to h / 2 (the temperature at which half of the resin flows out) is defined as the softening point.
The glass transition point was raised from room temperature to 200 ° C. at 10 ° C./min using a differential scanning calorimeter DSC-60 manufactured by Shimadzu Corporation, and then cooled to room temperature at a temperature lowering rate of 10 ° C./min. When measured at ° C./min, a curve in which the height h of the baseline below the glass transition point and the baseline above the glass transition point is ½ is defined as the glass transition point (Tg).
[0079]
Comparative Example 1
Non-linear polyester resin (A) Mw: 80,000 40 parts Linear polyester resin (B) Mw: 10,000 45 parts Hybrid resin (C) 15 parts Polyester (Mw 50,000) / Styrene-acrylic (Mw 200,000) = 80 / 20
Ti-Fe colorant 25 parts (Ti content: 8.0 wt%, average primary particle size 0.03 μm)
Charge control agent (Spiron Black TR-H: Hodogaya Chemical Co., Ltd.) 2 parts Low molecular weight polypropylene 3 parts A mixture of the above composition is sufficiently stirred and mixed in a Henschel mixer and then heated at a temperature of 130 to 140 ° C. for about 30 minutes. After melting and cooling to room temperature, the obtained kneaded product was pulverized and classified by a jet mill to obtain a toner having a volume average particle size of 8.0 μm and a particle size distribution of 35% by number of particles of 5 μm or less. 0.8 part of an additive (R-972: manufactured by Clariant Japan) was added to 100 parts of the toner, and after stirring and mixing with a Henschel mixer, particles having a large particle diameter were removed through a mesh to obtain a final toner.
The saturation magnetization σs of the toner was 35 emu / g.
A developer having a toner concentration of 2.5 parts by weight was prepared using this toner and a carrier in which spherical ferrite particles having an average particle diameter of 80 μm were coated with a silicone resin.
[0080]
Comparative Example 2
(Toner prescription)
Non-linear polyester resin (A) Mw: 80,000 40 parts Linear polyester resin (B) Mw: 10,000 45 parts Hybrid resin (C) 15 parts Polyester (Mw 50,000) / Styrene-acrylic (Mw 200,000) = 80 / 20
25 parts of Ti-Fe colorant (Ti content: 50% by weight, average primary particle size 0.45 μm)
Charge control agent (Spiron Black TR-H: Hodogaya Chemical) 2 parts low molecular polypropylene 3 parts (weight average molecular weight: 6000)
The mixture having the above composition is sufficiently stirred and mixed in a Henschel mixer, heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and the resulting kneaded product is pulverized and classified with a jet mill. A toner having an average particle size of 8.0 μm and a particle size distribution of 35% by number of particles of 5 μm or less was obtained. 0.8 part of an additive (R-972: manufactured by Clariant Japan) was added to 100 parts of the toner, and after stirring and mixing with a Henschel mixer, particles having a large particle diameter were removed through a mesh to obtain a final toner.
The saturation magnetization σs of the toner was 0.4 emu / g.
A developer having a toner concentration of 2.5 parts by weight was prepared using this toner and a carrier in which spherical ferrite particles having an average particle diameter of 80 μm were coated with a silicone resin.
[0081]
Comparative Example 3
A developer similar to that of Example 1 was obtained except that the hybrid resin (C) of Example 1 was omitted.
[0082]
Comparative Example 4
The hybrid resin (C) of Example 1 was changed to a styrene-methyl metaallylate copolymer (Mw: 50,000, acid value: 23.3 mg KOH / g Tm: 109.7 ° C. Tg: 62.5 ° C.) Obtained the same developer as in Example 1.
[0083]
Example 2
(Toner prescription)
Non-linear polyester resin (A) Mw: 80,000 40 parts Linear polyester resin (B) Mw: 10,000 45 parts Hybrid resin (C) 15 parts Polyester (Mw 50,000) / Styrene-acrylic (Mw 200,000) = 80 / 20
20 parts of Ti-Fe colorant (Ti content: 25% by weight, average primary particle size 0.03 μm)
Charge control agent (Spiron Black TR-H: Hodogaya Chemical) 2 parts low molecular polypropylene 3 parts (weight average molecular weight: 6000)
The mixture having the above composition is sufficiently stirred and mixed in a Henschel mixer, heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and the resulting kneaded product is pulverized and classified with a jet mill. A toner having an average particle size of 8.0 μm and a particle size distribution of 35% by number of particles of 5 μm or less was obtained. 0.8 part of an additive (R-972: manufactured by Clariant Japan) was added to 100 parts of the toner, and after stirring and mixing with a Henschel mixer, particles having a large particle diameter were removed through a mesh to obtain a final toner.
The saturation magnetization σs of the toner was 3.5 emu / g.
A developer having a toner concentration of 2.5 parts by weight was prepared using this toner and a carrier in which spherical ferrite particles having an average particle diameter of 80 μm were coated with a silicone resin.
[0084]
Example 3
Non-linear polyester resin (A) Mw: 80,000 40 parts Linear polyester resin (B) Mw: 10,000 45 parts Hybrid resin (C) 15 parts Polyester (Mw 50,000) / Styrene-acrylic (Mw 200,000) = 80 / 20
25 parts of Ti-Fe colorant (Ti content: 15% by weight, average primary particle size 0.25 μm)
Charge control agent (Spiron Black TR-H: Hodogaya Chemical) 2 parts low molecular polypropylene 3 parts (weight average molecular weight: 6000)
The mixture having the above composition is sufficiently stirred and mixed in a Henschel mixer, heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and the resulting kneaded product is pulverized and classified with a jet mill. A toner having an average particle size of 8.0 μm and a particle size distribution of 35% by number of particles of 5 μm or less was obtained. 0.8 part of an additive (R-972: manufactured by Clariant Japan) was added to 100 parts of the toner, and after stirring and mixing with a Henschel mixer, particles having a large particle diameter were removed through a mesh to obtain a final toner.
The saturation magnetization σs of the toner was 17.5 emu / g.
A developer having a toner concentration of 2.5 parts by weight was prepared using this toner and a carrier in which spherical ferrite particles having an average particle diameter of 80 μm were coated with a silicone resin.
[0085]
Example 4
A developer was obtained in the same manner as in Example 3 except that the hybrid resin of Example 3 was changed to a resin having the characteristics shown in Example 4 of Table 1.
[0086]
Example 5
A developer was obtained in the same manner as in Example 4 except that the non-linear resin and linear resin of Example 4 were changed to a resin having the characteristics shown in Example 5 of Table 1.
[0087]
Example 6
A developer was obtained in the same manner as in Example 5 except that the non-linear resin and the linear resin in Example 5 were changed to a resin having the characteristics shown in Example 6 in Table 1.
[0088]
Example 7
A developer was obtained in the same manner as in Example 6 except that the non-linear resin and the linear resin in Example 6 were changed to those having the characteristics shown in Example 7 in Table 1.
[0089]
Example 8
A developer was obtained in the same manner as in Example 7, except that the toner particle size distribution of Example 7 was changed to a toner having a volume average particle size of 6.5 μm and a particle size distribution of 65% by number below 5 μm. It was.
[0090]
Example 9
A developer was obtained in the same manner as in Example 8, except that the low molecular weight polypropylene in Example 8 was changed to carnauba wax.
[0091]
Each developer is evaluated as follows, and the evaluation results are shown in Tables 2 and 3.
(Fixability)
Using a device in which the fixing unit of RICOH Co., Ltd. MF-200, which uses a Teflon roller as a fixing roller, was modified, Ricoh type 6200 paper was set on this and a copying test was performed. The hot offset occurrence temperature was determined by changing the fixing temperature. The evaluation conditions for cold offset are 140 mm / sec for the linear velocity of paper feed, the surface pressure is 1.2 kgf / cm ² , the nip width is 3 mm, and the evaluation conditions for high temperature offset are the linear velocity for paper feed is 50 mm / sec, and the surface pressure is 2 0.0 Kgf / cm ² and a nip width of 4.5 mm.
The cold offset occurrence temperature and the high temperature offset occurrence temperature were determined as follows.
(Cold offset) Good ◎: Less than 125 ° C, ◯: 125-135, □: 135-145, Δ: 145-155, x: 155 or more Bad (hot offset) Good ◎: 201 ° C or more, ○: 200-191 ° C, □: 190-181 ° C, Δ: 180-171, x: 170 or less.
[0092]
(Evaluation of grindability)
The toner that was crushed to an average particle size of 1 mm or less was determined by the processing amount per unit time when it was pulverized under certain conditions with an IDS type pulverizer manufactured by Nippon Pneumatic Co., Ltd., and evaluated according to the following criteria.
Good ◎: 7 kg or more, ○: 7-5 kg, □: 5-3 kg, Δ: 3-2 kg, X: less than 2 kg Evil
(Cover evaluation)
In the fogging evaluation, the toner density adhered to the non-image area after the initial and 100,000 sheets was evaluated in five stages according to the following criteria.
Good ◎: Very good, ○: Good, □: Normal, △: Bad, ×: Very bad Evil [0094]
(Environmental change assessment)
The environmental stability is obtained by the blow-off method for the amount of charge in a low-temperature and low-humidity environment of 10 ° C. and 20% and in a high-temperature and high-humidity environment of 30 ° C. and 80%. After the calculation, it was evaluated in five levels according to the following criteria.
Environmental fluctuation rate (%) = ((low temperature and low humidity charge amount−high temperature and high humidity charge amount) / low temperature and low humidity charge amount) × 100
Good ◎: Less than 50%, ○: 50-60%, □: 60-70%, Δ: 70-80%, x: 80% or more
(Heat resistant storage stability evaluation)
20 g of the toner sample was put in a 20 ml glass bottle and left in a high temperature bath at 60 ° C. for 4 hours, and then the penetration was evaluated according to the following criteria in a penetration test (JIS K2235-1991).
Good ◎: 10 mm or more, ○: 9.9-5 mm, Δ: 4.9-3 mm, X: 2.9-0 mm Evil
(Fine line reproducibility)
Using Ricoh Co., Ltd. MF-200, an image evaluation test was performed to evaluate fine line reproducibility. Evaluation was performed in five stages according to the following criteria.
◎: Very good, ○: Good, □: Normal, △: Bad, ×: Very bad [0097]
(Toner coloring power)
Images with toner adhesion amounts of 0.5 mg / cm ² and 1.0 mg / cm ² were prepared using a copying machine MF-200 manufactured by Ricoh Co., Ltd., and the image density was measured with a Macbeth densitometer. The higher the image density, the greater the coloring power.
[0098]
(Toner scattering)
The Ricoh Co., Ltd. copier MF-200 made 100,000 copies, and the white stain attached to the inside of the front door of the machine was measured with a Macbeth densitometer. The Macbeth density of white paper is 0.07, and the higher this value, the worse the toner scattering.
[0099]
(Image density, background stain)
Ricoh Co., Ltd. Copier MF-200 was used to make 100,000 copies, and the image density and background stain at 50,000 sheets and 100,000 sheets were measured with a Macbeth densitometer.
[0100]
[Table 2]

[0101]
[Table 3]

[0102]
【The invention's effect】
As described above, according to the electrostatic image developing toner of claim 1, the hybrid resin (C) in which the resin component contains the same kind of polymer unit as the non-linear polymer resin (A) and the linear polymer resin (B). In addition, since a black iron oxide compound containing 10 to 45 wt% of a titanium component as a colorant with respect to Fe atoms is used as a colorant, the non-linear polymer and the linear polymer are appropriately compatible, High image quality, low-temperature fixability and hot offset resistance can be achieved at the same time, and a good image without heat storage, productivity and fog can be formed.
[0103]
According to the toner for developing an electrostatic charge image of claim 2, since the saturation magnetization σs of the toner is 0.5 to 30 emu / g, the developability on the photosensitive member is not deteriorated, , Dirt will not worsen.
[0104]
According to the electrostatic image developing toner of claim 3, since the average primary particle size of the black iron oxide compound is 0.05 to 2.0 μm, the dispersibility in the toner is very excellent.
[0105]
According to the electrostatic image developing toner of claim 4, since the resins (A), (B), and (C) all contain at least a polyester unit, the non-linear polymer and the linear polymer are appropriately compatible. Thus, a toner satisfying a wide fixing temperature range and image quality such as fogging can be obtained without impairing the pulverization property and heat-resistant storage stability.
[0106]
According to the electrostatic image developing toner of claim 5, since the resins (A), (B), and (C) all contain at least a polyamide unit, the non-linear polymer and the linear polymer are appropriately compatible. Thus, a toner satisfying a wide fixing temperature range and image quality such as fogging can be obtained without impairing the pulverization property and heat-resistant storage stability.
[0107]
According to the toner for developing an electrostatic charge image of claim 6, the softening point (Tm) and the glass transition point (Tg) of the resins (A), (B), and (C) are represented by the formulas (I) to (III). Satisfied, there is an effect of improving fog, and compatibility is not deteriorated when the toner is kneaded, and both low-temperature fixability and hot offset property can be achieved, and a sufficient fixable temperature range can be maintained.
[0108]
According to the toner for developing an electrostatic charge image according to claim 7, since the toner has a volume average particle diameter of 4 to 7.5 μm and contains 60 to 80% by number of particles of 5 μm or less, fine line reproduction is achieved. In addition, there is no deterioration in transfer efficiency or blade cleaning performance.
[0109]
According to the electrostatic image developing toner of claim 8, since the wax component contains at least one of carnauba wax, rice wax and ester wax of 0.5 to 20% by weight, it is uniform in the binder resin. Dispersion is possible.
[0110]
According to the process cartridge of the ninth aspect, since the toner of the present invention is used, a process cartridge having excellent image quality can be provided.
[0111]
According to the image forming apparatus of the tenth aspect, since the toner of the present invention is used, an image forming apparatus having a contact charging device with excellent image quality can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an example of a process cartridge.
FIG. 2 is a graph showing charging characteristics of contact charging.
FIG. 3 is a schematic configuration diagram illustrating an example of a contact charging device using roller charging.
FIG. 4 is a schematic configuration diagram showing an example of a contact charging device using brush charging.
DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Photoconductor 3 Charging means 4 Developing means 5 Cleaning means 10 Photoconductor drum 11 Charging roller 12 Core metal 13 Conductive rubber layer 14 Power supply 20 Photoconductor 21 Fur brush roller or magnetic brush roller 22 Core metal 23 Brush part 24 Power supply

Claims (8)

In the electrostatic charge developing toner containing a resin component, a wax component, and a colorant as essential components, the saturation magnetization σs of the toner is 17.5 to 30 emu / g, and the resin component is a non-linear polymer resin (A), Obtained by carrying out the polycondensation reaction and the addition polymerization reaction in parallel in the same reaction vessel using the linear polymer resin (B) and the mixture containing the raw material monomer of the condensation polymerization resin and the raw material monomer of the addition polymerization resin. Resin (C), wherein (A), (B), and (C) contain at least the same type of polymer unit, and as the colorant, the titanium component is converted to Ti atoms in terms of Ti atoms. A toner for developing electrostatic images, comprising using a black iron oxide compound containing 10 to 45% by weight. The electrostatic image developing toner according to claim 1, wherein the black iron oxide compound has an average primary particle size of 0.05 to 2.0 μm. The electrostatic image developing toner according to claim 1, wherein the resins (A), (B), and (C) all contain at least a polyester unit. The softening point (Tm) and glass transition point (Tg) of the resins (A), (B), and (C) satisfy the following formulas (I) to (III). Toner for developing electrostatic images.

The electrostatic image developing toner according to claim 1, wherein the toner has an average volume particle diameter of 4 to 7.5 μm and contains 60 to 80% by number of particles of 5 μm or less. The toner for developing an electrostatic charge image according to any one of claims 1 to 5, containing 0.5 to 20% by weight of carnauba wax as a wax component. In a process cartridge which integrally supports at least one unit selected from a photosensitive member, a charging unit, a developing unit, and a cleaning unit and is detachably provided in the main body of the image forming apparatus, the developing unit is a toner (developer) A process cartridge, wherein the toner (developer) is the electrostatic image developing toner according to claim 1. It has at least a charging device, and the charging device makes charging by bringing a charging member into contact with the latent image carrier and applying a voltage to the charging member, and the toner (developer) to be used is claimed. An image forming apparatus comprising the electrostatic image developing toner according to any one of 1 to 6.

Images