JP4457535B2 - Toner and electrophotographic apparatus - Google Patents

Description

（Ｒ¹，Ｒ⁴は水素原子、アルキル基又は置換基を有してもよい芳香環を示し、Ｒ²，Ｒ³は置換されてもよい芳香環を示す。Ｘはアルカリ金属を表す）
【００５９】
また、本形態ではトナーの電荷制御の目的、及びオイルレス定着をより強固なものとするために、結着樹脂に上記した定着助剤と電荷制御剤を併用配合する。好ましい材料としては（化６）に示すサリチル酸誘導体の金属塩が用いられる。
【００６０】
【化６】

【００６１】
この構成により、オイルレス定着において広範囲の非オフセット温度域を確保できると共に、定着時での帯電作用による画像乱れを防止できる。これは定着助剤のもつ酸価を有する官能基と金属塩の帯電極性の効果と思われる。また連続使用時での帯電量の低下を防止できる。現像でのブレード融着を抑えられる。
【００６２】
添加量は結着樹脂１００重量部に対し、０．５〜５重量部が好ましい。より好ましくは１〜４重量部、さらに好ましくは３〜４重量部である。０．５重量部よりも少ないと、帯電作用効果が無くなる。５重量部より大きいとカラー画像での色濁りが目立ってくる。
【００６３】
また、本形態のトナーでは結着樹脂としてポリエステル樹脂を使用し、前記した定着助剤、電荷制御剤との併用、そしてトナー又はポリエステル樹脂の分子量を特定することにより、混練時での定着助剤、電荷制御剤の分散をより良好なものとすることができ、帯電性の安定化が図られる。またトナー凝集も防止することが可能となり、長期間連続して使用しても感光体、中間転写体、現像ローラへのフィルミングを防止することが可能となる。定着での高透光性、高色再現性を確保でき、かつ定着オイルを必要とせずとも、より高温度域にまでオフセット幅を広げられる構成を創出した。現像においては帯電性を上げるためにより強いストレスがかけられ、また中間転写体のクリーニングにおいてもクリーニング性を上げるため強い負荷がかけられる。また現像ユニット自体が公転する構成によりトナーに強いストレスが掛かる状態においても高透光性を維持しながら耐久性、転写性、リサイクル性、帯電性をより良好なものとし、定着性と現像性、耐久性をより良好に両立させることが可能となることを見い出した。シャープな分子量分布を具備することで、高透光性を確保できかつ定着オイルを必要とせずとも、オフセットを防げる構成を創出した。
【００６４】
具体的には結着樹脂としてＧＰＣにおける分子量分布で、２×１０³〜３×１０⁴の領域に少なくとも一つの分子量極大ピークを有し、かつ、高分子量領域に存在する成分として３×１０⁴以上の分子量成分を結着樹脂全体に対し５％以上有し、重量平均分子量が１万〜２０万、Ｚ平均分子量が２万〜５０万、重量重量平均分子量と数平均分子量の比（重量平均分子量／数平均分子量）が３〜１００、Ｚ平均分子量と数平均分子量の比（Ｚ平均分子量／数平均分子量）が１０〜２０００、高化式フローテスタによる１／２法による溶融温度（以下軟化点）が８０〜１５０℃、流出開始温度は８０〜１２０℃、樹脂のガラス転移点が４５〜６８℃の範囲であるポリエステル樹脂を成分とすることが好ましい。
【００６５】
好ましくは重量平均分子量が１万〜１２万、Ｚ平均分子量が２万〜３０万、重量平均分子量／数平均分子量が３〜５０、Ｚ平均分子量／数平均分子量が１０〜１０００、軟化点が９０〜１４０℃、流出開始温度は８５〜１１５℃、ガラス転移点が５２〜６５℃の範囲であるポリエステル樹脂を成分とすることが好ましい。より好ましくは重量平均分子量が１万〜４万、Ｚ平均分子量が２万〜１０万、重量平均分子量／数平均分子量が３〜２０、Ｚ平均分子量／数平均分子量が１０〜１００、軟化点が１０５〜１３５℃、流出開始温度は９０〜１２０℃、ガラス転移点が５８〜６５℃の範囲であるポリエステル樹脂を成分とすることが好ましい。
【００６６】
また高分子量領域に存在する成分として、好ましくは１×１０⁵以上の分子量成分を結着樹脂全体に対し３％以上有することが好ましい。さらには高分子量領域に存在する成分として、３×１０⁵以上の分子量成分を結着樹脂全体に対し０．５％以上有することが好ましい。
【００６７】
好ましくは高分子量領域に存在する成分として、８×１０⁴〜１×１０⁷の分子量成分を結着樹脂全体に対し３％以上有し、かつ１×１０⁷以上の成分は含有しない構成が好ましい。
【００６８】
更に好ましくは、高分子量領域に存在する成分として、３×１０⁵〜９×１０⁶の高分子量成分を結着樹脂全体に対し１％以上有し、かつ９×１０⁶以上の成分は含有しない構成である。
【００６９】
更に好ましくは、高分子量領域に存在する成分として、７×１０⁵〜６×１０⁶の高分子量成分を結着樹脂全体に対し１％以上有し、かつ６×１０⁶以上の成分は含有しない構成である。
【００７０】
高分子量成分が多すぎると、あるいは巨大すぎると混練時に巨大分子量成分が残留し、透光性を阻害する。また樹脂自体の製造効率が低下する。現像ローラ供給ローラに不要な傷を付け画像に縦筋を生じさせる。また定着助剤の分散性が低下する。
【００７１】
結着樹脂の重量平均分子量が１万より小さく、Ｚ平均分子量が２万より小さく、重量平均分子量／数平均分子量が３より小さく、Ｚ平均分子量／数平均分子量が１０より小さく、軟化点が８０℃より小さく、流出開始温度が８０℃より小さく、ガラス転移点が４５℃より小さくとなると、混練時の分散性が低下し、カブリの増加や耐久性の悪化を招く。また混練時の混練ストレスが充分にかからず、分子量を適正値に維持できなくなる。定着助剤の分散性が低下し耐オフセット性、高温保存性の悪化、さらには中間転写体でのクリーニング不良、感光体へのフィルミングが発生する。
【００７２】
結着樹脂の重量平均分子量が２０万より大きく、Ｚ平均分子量が５０万より大きく、重量平均分子量／数平均分子量が１００より大きく、Ｚ平均分子量／数平均分子量が２０００より大きく、軟化点が１５０℃より大きく、流出開始温度が１２０℃より大きく、ガラス転移点が６８℃より大きくとなると、機械の処理中の負荷が過大となり生産性の極端な低下や、カラー画像での透光性の低下や定着強度の低下につながる。
【００７３】
さらに、溶融混練処理されたトナーのＧＰＣにおける分子量分布が、２×１０³〜３×１０⁴の領域に少なくとも一つの分子量極大ピークを有し、５×１０⁴〜１×１０⁶の領域に少なくとも一つの分子量極大ピーク又はショルダーを有する構成とすることである。好ましくはトナーの低分子量側に存在する分子量極大ピークが、３×１０³〜２×１０⁴の領域に少なくとも一つ有し、さらに好ましくは４×１０³〜２×１０⁴の領域に少なくとも一つ有する構成である。
【００７４】
また、トナーの高分子量側に存在する分子量極大ピーク又はショルダーの位置が、６×１０⁴〜７×１０⁵の領域に少なくとも一つ有し、さらに好ましくは８×１０⁴〜５×１０⁵の領域に分子量極大ピーク又はショルダーを少なくとも一つ有する構成である。
【００７５】
低分子量側に存在するトナーの分子量分布の分子量極大ピーク位置が、２×１０³より小さくなると耐久性が悪化し、３×１０⁴より大きくなると定着性が悪化し、透光性が低下する。
【００７６】
また、高分子量側に存在するトナーの分子量分布の分子量極大ピーク又はショルダーの位置が、５×１０⁴より小さくなると、耐オフセット性が低下し、保存安定性が悪化する。現像性の悪化と廃トナーリサイクル性も低下する。１×１０⁶より大きくなると粉砕性が低下し、生産効率の低下を招く。
【００７７】
さらに、トナーの高分子量領域に存在する成分として、５×１０⁵以上の高分子量成分の含有量が結着樹脂全体に対し１０ｗｔ％以下であることが好ましい。５×１０⁵以上の高分子量領域に存在する成分が多くなり、あるいは巨大の状態は、混練時にトナー構成材料に均一な混練ストレスが加わらず、混練状態が不具合となった結果である。これにより透光性が著しく阻害される。また分散不良によるカブリの増大、現像ローラ、供給ローラの傷の発生、トナーの粉砕性が悪化し製造効率が低下する。
【００７８】
より好ましくは、５×１０⁵以上の高分子量成分の含有量が結着樹脂全体に対し５％以下であり、さらに好ましくは、１×１０⁶以上の高分子量成分の含有量が結着樹脂全体に対し１％以下、若しくは含有しない構成である。
【００７９】
また、トナーのＧＰＣクロマトグラムにおける分子量分布で、２×１０³〜３×１０⁴の領域に存在する分子量極大ピークの分子量分布の高さをＨａ、５×１０⁴〜１×１０⁶の領域に存在する分子量極大ピーク又はショルダーの高さをＨｂとすると、Ｈｂ／Ｈａを０．１５〜０．９とすることである。
【００８０】
Ｈｂ／Ｈａが、０．１５より小さくなると耐オフセット性が悪化し、保存安定性も低下し、現像スリーブや感光体へのフィルミングを助長する結果となる。０．９より大きくなると現像ローラ供給ローラに傷を生じさせ、また粉砕性が悪化し、生産性が低下しコストアップにつながる。より好ましくは、Ｈｂ／Ｈａが０．１５〜０．７、さらに好ましくは、Ｈｂ／Ｈａが０．２〜０．６である。
【００８１】
また、高透光性を確保できかつ定着オイルを必要とせずとも、オフセット防止のため、トナーのＧＰＣにおける分子量分布で、２×１０³〜３×１０⁴の領域に少なくとも一つの分子量極大ピーク、５×１０⁴〜１×１０⁶の領域に少なくとも一つの分子量極大ピーク又はショルダーを有する構成で、分子量５×１０⁴〜１×１０⁶の領域に存在する分子量分布の極大ピーク又はショルダーに相当する分子量値よりも大きい領域にある分子量曲線に着目し、その分子量分布の極大ピーク又はショルダーの高さを１と基準として、その分子量極大ピーク又はショルダーの高さに対して９０％の高さに相当する分子量をＭ９０、分子量極大ピーク又はショルダーの高さの１０％の高さに相当する分子量をＭ１０とした場合、Ｍ１０／Ｍ９０が０．５〜８とすることで実現できる。さらには、（Ｍ１０−Ｍ９０）／Ｍ９０が０．１〜７とすることで実現できる。
【００８２】
上記Ｍ１０／Ｍ９０、さらには、（Ｍ１０−Ｍ９０）／Ｍ９０の値（分子量分布曲線の傾き）を規定することは超高分子量成分の分子切断の状態を定量化できるものであり、この値が上記記載した範囲内（分子量分布曲線の傾きが急峻であることを示唆する）である場合には、透光性を阻害している超高分子量成分が混練時の切断により無くなり、高透光性を有するようになる。さらには、この高分子側に現れるピ−ク又はショルダーを形成する高分子量成分が耐オフセット性に寄与し、オイルを使用せずともカラートナーのオフセットの発生を防ぐことが可能となる。
【００８３】
さらにはこの超高分子量成分を分子切断する際に、結着樹脂中で定着助剤や電荷制御剤の均一分散化処理を可能とすることができ、帯電量が均一化し、鮮明な解像度を有し、長期連続使用しても耐久性を悪化させることがない。また中間転写体のクリーニング性が向上し、現像ローラでの縦筋の発生もなく、転写時の中抜けを防止でき高効率な転写性を得ることが可能となる。
【００８４】
Ｍ１０／Ｍ９０の値が８より大きく、または（Ｍ１０−Ｍ９０）／Ｍ９０が７より大きい場合には、依然超高分子量成分が残存し、透光性を阻害する。Ｍ１０／Ｍ９０の値が０．５より小さく、または（Ｍ１０−Ｍ９０）／Ｍ９０が０．１より小さい場合には、混練時の機械的負荷が過大となり生産性が低下する。トナーの耐久性が低下する。より好ましくはＭ１０／Ｍ９０の値が０．５〜６であり、（Ｍ１０−Ｍ９０）／Ｍ９０が０．１〜４．５である。さらに好ましくは、Ｍ１０／Ｍ９０の値が０．５〜４．５であり、（Ｍ１０−Ｍ９０）／Ｍ９０が０．１〜３．５である。
【００８５】
これにより、デジタル高画質化、高彩色再現性カラー化、接触式一成分現像における現像ローラ、供給ローラでの長期安定して使用可能ならしめ、定着ローラにオフセット防止用のオイルを使用しないで高透光性と耐オフセット性の両立を図れ、さらにはクリーナプロセスの実現、中間転写体を使用した転写工程での高転写性を実現することができる。
【００８６】
上記した結着樹脂を溶融混練処理において高せん断力にて混練することで従来にない特性を発現することが可能となる。オイルを用いない定着でカラートナーの高い透光性と耐オフセット性を両立させることが出来る。つまり超高分子量成分を付与した結着樹脂を高せん断力により、超高分子量成分を低分子量化しそれにより高透光性が発現し、さらにはこの低分子量化した超高分子量成分の存在により耐オフセット性も満足できる。また超高分子量成分を有するため、混練時に高いせん断力がかかるため、定着助剤がより均一に分散させることが可能となり、より透光性が良化し、非オフセット性、高画質、高彩色再現性が得られる。
【００８７】
溶融混練処理後のトナーの重量平均分子量が８０００〜１８万、Ｚ平均分子量が１８０００〜４５万、重量平均分子量と数平均分子量の比（重量平均分子量／数平均分子量）が３〜８０、Ｚ平均分子量と数平均分子量の比（Ｚ平均分子量／数平均分子量）が１０〜１０００となることである。
【００８８】
この適性範囲にトナーを高せん断力による混練処理することにより、オイルを用いない定着でカラートナーの高透光性と耐オフセット性を両立させることが可能となる。
【００８９】
好ましくは重量平均分子量が８０００〜１０万、Ｚ平均分子量が１８０００〜３０万、重量平均分子量／数平均分子量が３〜６０、Ｚ平均分子量／数平均分子量が１０〜５００であることが好ましい。
【００９０】
さらに好ましくは重量平均分子量が１万〜４万、Ｚ平均分子量が２万〜８万、重量平均分子量／数平均分子量が３〜３０、Ｚ平均分子量／数平均分子量が１０〜５０であることが好ましい。
【００９１】
重量平均分子量が８０００より小さく、Ｚ平均分子量が１８０００より小さく、重量平均分子量／数平均分子量が３より小さく、Ｚ平均分子量／数平均分子量が１０より小さくなると、混練ストレスが充分にかからず、分子量を適正値に維持できなくなる。定着助剤の分散性が低下し耐オフセット性、高温保存性の悪化、さらには中間転写体でのクリーニング不良、感光体へのフィルミングが発生する。
【００９２】
重量平均分子量が１８万より大きく、Ｚ平均分子量が４５万より大きく、重量平均分子量／数平均分子量が８０より大きく、Ｚ平均分子量／数平均分子量が１０００より大きくなると、せん断力の圧力が働きすぎ、逆に電荷制御剤等の内添剤が相互に凝集を生じ、分散性の低下につながり、クリーナプロセス時のかぶりの増加、画像濃度の低下、転写不良の発生を招く。また定着強度の低下や、透光性、光沢度が低下する。
【００９３】
また結着樹脂はＴＨＦ不溶成分が５重量％以下、好ましくはＴＨＦ不溶成分を有しないことである。ＴＨＦ不溶成分が５重量％より多いとカラー画像の透光性を悪化させる要因となり、画質を劣化させていまう。
【００９４】
本形態に好適に使用される結着樹脂は、アルコール成分とカルボン酸、カルボン酸エステル及びカルボン酸無水物等のカルボン酸成分との重縮合によって得られるポリエステル樹脂が好適に使用される。
【００９５】
２価カルボン酸又は低級アルキルエステルとしては、マロン酸、コハク酸、グルタル酸、アジピン酸、ヘキサヒドロ無水フタル酸などの脂肪族二塩基酸、マレイン酸、無水マレイン酸、フマル酸、イタコン酸、シトラコン酸などの脂肪族不飽和二塩基酸、及び無水フタル酸、フタル酸、テレフタル酸、イソフタル酸などの芳香族二塩基酸、及びこれらのメチルエステル、エチルエステル等を例示することが出来る。この中でコハク酸、フタル酸、テレフタル酸、イソフタル酸等の芳香族二塩基酸及びそれらの低級アルキルエステルが好ましい。コハク酸とテレフタル酸、若しくはフタル酸とテレフタル酸とを組合わせた使用が好ましい。
【００９６】
３価以上のカルボン酸成分としては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、２，５，７−ナフタレントリカルボン酸、１，２，４−ナフタレントリカルボン酸、１，２，４−ブタントリカルボン酸、１，２，５−ヘキサトリカルボン酸、１，３−ジカルボキシルー２−メチルー２−メチレンカルボキプロパン、テトラ（メチレンカルボキシル）メタン、１，２，７，８−オクタンテトラカルボン酸、ピロメリット酸、エンポール三量体酸及びこれらの酸無水物、アルキル（炭素数１〜１２）エステル等が挙げられる。
【００９７】
２価アルコールとしては、エチレングリコール、１，２−プロピレングリコール、１，３−プロピレングリコール、１，３−ブチレングリコール、１，４−ブチレングリコール、１，６−ヘキサンジオール、ネオペンチルグリコール、ジエチレングリコール、ジプロピレングリコール、ビスフェノールＡエチレンオキサイド付加物、ビスフェノールＡプロピレンオキサイド付加物、などのジオール、グレセリン、トリメチロールプロパン、トリメチロールエタンなどのトリオール、及びそれらの混合物を例示することが出来る。この中でネオペンチルグリコール、トチメチロールプロパン、ビスフェノールＡエチレンオキサイド付加物、ビスフェノールＡプロピレンオキサイド付加物が好ましい。
【００９８】
３価以上のアルコール成分としては、ソルビトール、１，２，３，６−ヘキサンテトロール、１，４−ソルビタン、ペンタエリスリトール、ジペンタエリスリトール、トリペンタエリスリトール、１，２，４−ブタントリオール、１，２，５−ペンタントリオール、グリセロール、２−メチルプロパントリオール、２−メチル−１，２，４−ブタントリオール、トリメチロールエタン、トリメチロールプロパン、１，３，５−トリヒドロキシメチルベンゼン等が挙げられる。
【００９９】
重合は公知の重縮合、溶液重縮合等を用いることが出来る。これによって耐塩ビマット性やカラートナーの色材の色を損なうことなしに、良好なトナーを得ることができる。
【０１００】
多価カルボン酸と多価アルコールの使用割合は通常、カルボキシル基数に対する水酸基数の割合（ＯＨ／ＣＯＯＨ）で０．８〜１．４が一般的である。
【０１０１】
樹脂及びトナーの分子量は、数種の単分散ポリスチレンを標準サンプルとするゲル浸透クロマトグラフィー（ＧＰＣ）によって測定された値である。
【０１０２】
装置は、東ソー社製ＨＰＬＣ８１２０シリーズ、カラムはＴＳＫｇｅｌ ｓｕｐｅｒＨＭ−Ｈ Ｈ４０００／Ｈ３０００／Ｈ２０００（７．８ｍｍ径、１５０ｍｍ×３）、溶離液ＴＨＦ（テトラヒドロフラン）、流量０．６ｍｌ／ｍｉｎ、試料濃度０．１％、注入量２０μＬ、検出器ＲＩ、測定温度４０℃、測定前処理は試料をＴＨＦに溶解後０．４５μｍのフィルターでろ過しシリカ等の添加剤を除去した樹脂成分を測定する。測定条件は、対象試料の分子量分布が、数種の単分散ポリスチレン標準試料により得られる検量線における分子量の対数とカウント数が直線となる範囲内に包含される条件である。
【０１０３】
定着助剤は、数種の単分散ポリスチレンを標準サンプルとするＧＰＣによって測定された値であるが、上記した樹脂やトナーと異なり、装置は、ＷＡＴＥＲＳ製ＧＰＣ−１５０Ｃ、カラムはＳｈｏｄｅｘ ＨＴ−８０６Ｍ（８．０ｍｍＩ．Ｄ．−３０ｃｍ×２）、溶離液はｏ−ジクロロベンゼン、流量は１．０ｍＬ／ｍｉｎ、試料濃度は０．３％、注入量は２００μＬ、検出器はＲＩ、測定温度は１３０℃、測定前処理は試料を溶媒に溶解後０．５μｍの金属焼結フィルターでろ過処理した。測定条件は、対象試料の分子量分布が、数種の単分散ポリスチレン標準試料により得られる検量線における分子量の対数とカウント数が直線となる範囲内に包含される条件である。
【０１０４】
また、結着樹脂の軟化点は、島津製作所のフローテスタ（ＣＦＴ５００）により、１ｃｍ³の試料を昇温速度６℃／分で加熱しながらプランジャーにより約９．８×１０⁵Ｎ／ｍ²の荷重を与え、直径１ｍｍ、長さ１ｍｍのダイから押し出して、このプランジャーのピストンストロークと温度との関係における昇温温度特性との関係から、ピストンストロークが立上がり始める温度が流出開始温度（Ｔｆｂ）、曲線の最低値と流出終了点の差の１／２を求め、それと曲線の最低値を加えた点の位置における温度を１／２法における溶融温度（軟化点Ｔｍ）となる。
【０１０５】
また樹脂のガラス転移点は示差走査熱量計を用い、１００℃まで昇温し、その温度にて３分間放置した後、降温速度１０Ｋ／ｍｉｎで室温まで冷却したサンプルを、昇温速度１０Ｋ／ｍｉｎで昇温して熱履歴を測定した際に、ガラス転移点以下のベースラインの延長線とピークの立上がり部分からピークの頂点までの間での最大傾斜を示す接線との交点の温度を言う。
【０１０６】
ＤＳＣによる吸熱ピークの融点は、島津製作所の示差熱量分析計ＤＳＣ−５０を使用した。５Ｋ／ｍｉｎで２００℃まで昇温し、５分間保温１０℃まで急冷後、１５分間放置後５Ｋ／ｍｉｎで昇温させ、吸熱（融解）ピークから求めた。セルに投入するサンプル量は１０ｍｇ±２ｍｇとした。
【０１０７】
高せん断力による混練により、より定着性現像性耐久性等の特性が向上する。
【０１０８】
具体的は、異方向に回転し、加熱または冷却が可能な対向する２本のロールを有し、一方のロール（ＲＬ１）のロール温度ともう一方のロール（ＲＬ２）のロール温度に温度差を設け、かつ前記ロール（ＲＬ１）と前記ロール（ＲＬ２）とを異なる周速で回転させて２本のロール間で混練処理することにより実現できる。さらには一方のロール（ＲＬ１）が前半部と後半部で温度差を有する構成とすることである。
【０１０９】
そしてそのロールの温度設定及び温度勾配、回転数及び負荷電流の混練条件と結着樹脂の軟化点、定着助剤の融点、添加量を最適な条件で処理することにより向上する。
【０１１０】
２本ロールの回転数比を１．１倍から２．５倍の範囲内で行うことにより混練時に適切なせん断力が生じ、結着樹脂の分子切断、着色剤等の内部添加剤の分散性が向上し、定着性、現像性が向上する。加熱してトナーを溶融し巻き付ける側のロールの回転比を高くする構成である。１．１倍以下であると適切なせん断力が生じず、分散性が向上せず、透光性が悪化する。逆に２．５倍以上であると、生産性が急激に低下し、また分散性が向上せず、現像性の悪化を招く。
【０１１１】
またこのときの２本のロールにかかる負荷電流値の比を１．２５〜１０の範囲となるような条件で混練することで、適切なせん断力が加わりより内添剤の分散性が向上する。この範囲よりも小さいと分散性が向上せず、透光性が悪化する。また生産性も低下する。逆にこの範囲よりも大きいと、ローラにかかる負荷が大きくなりすぎ、超高分子量成分がより低分子量化しすぎるため、非オフセット性が低下し、オフセットが発生するようになる。
【０１１２】
結着樹脂の軟化点よりも低い温度の定着助剤を添加した際、定着助剤の添加量を多くするほど、ロール温度を高くしなければ、ロールへの溶融巻付きが良好に行えない。通常低融点のものを添加することで、より低い温度により処理が可能となると考えられるが、離型作用が強く、ローラから離脱しやすくなる傾向にある。従って高温度により処理を行う必要があるが、高温度で処理すればせん断力が弱くなり定着助剤の分散性が低下する。逆に温度が低いと巻付きが不良化し、飛散や離脱が生じ、生産性が低下する。よってこのとき前半部のロール温度をＴｒｊ１、後半部のロール温度をＴｒｋ１、結着樹脂の軟化点（１／２法における溶融温度）をＴｍ、定着助剤のＤＳＣ法による融点をＴｗ、定着助剤の添加量をＳｗ（結着樹脂１００重量部に対する配合量（重量部）比）とすると、（数５）の関係を満たすように処理することにより、ロールへの溶融巻付きが良好に行えると共に、定着助剤の分散性を適切に行える。
【０１１３】
【数５】

【０１１４】
ｑの値が小さいと巻付きが不良化して定着助剤の分散性が向上しない。ｑの値を大きくして処理するとせん断力作用が十分にかからず、透光性の低下、中間転写体へのフィルミング、クリーニング不良を誘発する。
【０１１５】
またトナーを溶融し巻き付ける一方のロールにおいて、原料を供給する前半部（ＩＮ側）と混練された材料を取出す後半部（ＯＵＴ側）とに温度差を設ける構成とする。ＩＮ側では供給された材料をローラに溶融巻付きさせるため温度を高めに設定し、ＯＵＴ側は温度を下げて材料にせん断力を与えて、樹脂の分子切断と定着助剤の分散性を向上させる。ＩＮ側からＯＵＴ側に搬送された材料が温度差を設けることは、ＩＮ側で結着樹脂がある程度溶融され、定着助剤が樹脂中でばらされた状態にあり、それがＯＵＴ側の低温度により強いせん断力を受け、分散性が均一なものと出来る。また樹脂の分子切断も適切に行える。このときＩＮ側のロール温度をＴｒｊ１、ＯＵＴ側のロール温度をＴｒｋ１、結着樹脂の軟化点をＴｍ、定着助剤の添加量をＳｗ（結着樹脂１００重量部に対する配合量（重量部）比）とすると、（数６）の関係を満たすように処理することにより、ロールへの溶融巻付きが良好に行えると共に、定着助剤の分散性を適切に行える。
【０１１６】
【数６】

【０１１７】
ｊの値が大きいとＯＵＴ側でのせん断力が十分にかからず、定着助剤の分散性が向上しない。定着時の透光性が低下し、現像ローラでの縦筋、かぶり、中間転写体でのクリーニング不良が生じる。ｊの値を小さくして処理すると溶融膜のローラからの浮状態が発生し、逆にせん断力作用が十分にかからず、透光性の低下、中間転写体へのフィルミング、クリーニング不良を誘発する。
【０１１８】
以上の状態で処理することにより、混練時の高分子量の分子切断を適当な状態で行え、又内添剤特に顔料と電荷制御剤を均一に混練分散することができ、特にカラートナーでの透光性とオイルを使用しない定着において耐オフセット性の両立を実現させることが出来る。
【０１１９】
さらにより分散の均一性を高められ、高転写性、現像性を向上させることが可能となる。また高温高湿下、低温低湿下での特性を安定化させることが出来る。
【０１２０】
また本形態の現像プロセスにおいては、弾性又は剛性の現像ローラ上にゴムやメタル等の弾性ブレード等を一定の圧力により接触させ、トナーの薄層を形成して感光体と接触又は非接触により現像する構成である。一成分現像法としては、ウレタン樹脂からなるスポンジ系の供給ローラとシリコン樹脂又はウレタン樹脂からなる現像ローラを一定の食い込み量により接触させ、供給ローラから現像ローラにトナーを供給し、現像ローラ上に弾性体のゴムや金属ステンレスのドクターブレードを接触して、または金属性のローラを現像ローラとアゲインスト（同方向）に回転接触して、トナーの薄層を形成し、それを感光体と接触または非接触にて直流または交流印可してトナー像を形成する現像法が好適に使用される。
【０１２１】
このとき、交流バイアスの周波数が０．５〜１０ｋＨｚ、交流バイアスが０．３〜１．２ｋＶ（ｐ−ｐ）であり、感光体と現像ローラ間の周速度比が１：１．２〜１：１．８とすることにより、ドットを忠実に再現でき、良好な現像γ特性とでき、高画質画像を実現できる。そして低地カブリ、高画像濃度が得られる。周波数が０．５〜５ｋＨｚ、交流バイアスが０．３〜１．０ｋＶ（ｐ−ｐ）であり、かつ感光体と現像ローラ間の周速度比が１：１．２〜１：１．５がより好ましく、更に好ましくは周波数が０．５〜２ｋＨｚ、交流バイアスが０．５〜０．９ｋＶ（ｐ−ｐ）であり、かつ感光体と現像ローラ間の周速度比が１：１．２〜１：１．４である。
【０１２２】
このとき、周波数が０．５ｋＨｚより小さいと、ドット再現性が悪化し、中間調再現性が悪化する。周波数が１０ｋＨｚより大きくなると、現像領域での追随ができず、効果が現れない。交流バイアスが０．３ｋＶ（ｐ−ｐ）より小さくなると、ベタ追随性維持効果が得られず、交流バイアスが１．２ｋＶ（ｐ−ｐ）より大きくなるとカブリが増大する。感光体と現像ローラ間の周速度比が１：１．２より小さいと（現像ローラが遅くなる）画像濃度が得にくい。感光体と現像ローラ間の周速度比が１：１．８より大きくなると（現像ローラ速度が上がる）とトナー飛散が多くなる。
【０１２３】
供給ローラと現像ローラは同方向に回転させ、現像ローラと供給ローラの周速を１：１〜０．８：０．２の割合で現像ローラを早くする構成とする。また現像ローラは感光体表面に９．８×１０²〜９．８×１０⁴（Ｎ／ｍ²）の圧力で圧接して感光体上の静電潜像が現像される。また弾性ブレードは５×１０³〜５×１０⁵（Ｎ／ｍ²）の圧力で現像ローラ上に圧接してトナー層が形成される。
【０１２４】
さらに、トナー溜めから供給されるトナーの供給量を現像ローラ上へ搬送する際の現像ローラ上のトナー搬送量を一定量に制御するため、ウレタン樹脂等からなるスポンジ状の供給ローラを、現像ローラに対し一定の食い込み量０．１〜１ｍｍで、現像ローラと接触させる構成が取られる。
【０１２５】
トナー溜めから供給されるトナーの供給量を現像ローラ上へ搬送する際の現像ローラ上のトナー搬送量を一定量に制御するため、ウレタン樹脂等からなるスポンジ状の供給ローラを現像ローラと接触させて具備する構成が取られる。これはトナーの搬送量を一定量に規制するために有効な手段である。
【０１２６】
しかし、この構成においては、長期使用していると現像ローラ上での傷や、ブレードに異物の付着により画像上に縦筋が生じる画像不良が発生しやすい。特にカラー定着性を向上させるために、低軟化性の結着樹脂の使用や、低融点離型剤を添加したトナーではより顕著に発生する。
【０１２７】
また、長期連続使用中に現像ローラ上のトナーの搬送量が低下したり、べた黒画像を取った場合に画像後半部の濃度が部分的に低下するベタ追随性不良が発生しやすい。現像ローラ上のトナーの帯電量を吸引式により測定すると帯電量が大きく低下していることが分かった。さらに追求すると供給ローラ部のトナーの帯電量が大きく増加しており、つまり画像濃度の低下はトナーの帯電量が低下しているのではなくて、現像ローラに供給される前の供給ローラ部においてチャージアップしており供給ローラから現像ローラへの供給能力が低下したためである。よってトナーの飛散を防ぎながら画像濃度を確保できる構成が必要になる。ドクターブレードの圧接力を高めてトナーの帯電能力を上げる構成も有効であるが、トナーの融着を招きやすく現像ローラに傷を生じさせる。
【０１２８】
そこで、本形態のトナー構成とすることにより、定着特性を犠牲にすることなく、現像ローラ上の縦筋の発生、ベタ追随性不良、トナーの融着を防止することができることを見い出した。
【０１２９】
これは樹脂中での均一分散が可能となり、帯電分布が安定化し供給ローラでのトナーの過帯電を抑えると共に、連続使用時の画像濃度を安定化でき、またべた追随性も良好なものとなる。均一分散によりトナーの流動性が維持でき現像ローラ上でのトナーの搬送状態をスムーズなものとし、搬送状態を常に安定化できる効果がある。特に高湿下での搬送状態の安定化に効果が大きい。このとき現像ローラ上のトナーの吸引式ファラデーケージ法によるトナーの帯電量が−５〜−４５μＣ／ｇであることが好ましい。−５μＣ／ｇ以下であるとトナー飛散が増大する。−４５μＣ／ｇ以上となると画像濃度が出にくい。
【０１３０】
また、本形態において、感光体の表面に形成されたトナー画像を、感光体の表面に無端状の中間転写体の表面を当接させて当該表面にトナー画像を転写させる一次転写プロセスが複数回繰り返し実行され、この後、この一次転写プロセスの複数回の繰り返し実行により中間転写体の表面に形成された重複転写トナー画像を複写用紙等の転写材に一括転写させる２次転写プロセスが実行されるよう構成された転写システムを具備する電子写真装置に好適に使用される。この時感光体と中間転写体は９．８×１０²〜２×１０⁵（Ｎ／ｍ²）の圧力で圧接して感光体上のトナーが転写される。また中間転写体表面に形成されたトナー像は中間転写体の表面を転写部材が記録紙を介して５×１０³〜２×１０⁵（Ｎ／ｍ²）圧力で押圧して記録材上にトナーが転写される。
【０１３１】
このとき、２次転写時に転写材に転写されずに残留するトナーをクリーニング除去することが必要であり、バイアスを印可したローラや、ファーブラシ等が使用される。このときトナーがクリーニングされにくいと、中間転写体との接触によりトナーがフィルミングを生じてしまう。またローラにより除去されたトナーをこのローラから金属プレートによりスクレープする際にその金属プレートに融着し、スクレープ不良が生じてしまう。特にカラー画像の光沢性、高透光性のカラー定着性を向上させるために、低軟化性の結着樹脂の使用や、低融点離型剤を添加したトナーではより顕著に発生し易くなる。
【０１３２】
そこで、本形態のトナーの使用により、トナーの帯電性の安定化が得られ、均一な帯電性を有し、地カブリが少なく転写時の中抜けを防止できるとともに高転写効率を得ることが可能となる。クリーニング性においては、樹脂中の均一分散性の向上、良好な帯電性、材料の有する離型性のため、クリーニング性を良好なものとし、フィルミング、スクレープ不良を回避できる。
【０１３３】
また、本形態において、回転する感光体とそれぞれ色の異なるトナーを有する現像手段とを備え前記感光体上にそれぞれ異なった色のトナー像を形成する複数の移動可能な像形成ユニットを円環状に配置した像形成ユニット群から構成され、像形成ユニット群全体を回転移動させ、感光体上に形成した異なる色のトナー像を転写材上に位置を合わせて重ねて転写してカラー像を形成するカラー電子写真装置に好適に使用される。
【０１３４】
像形成ユニットは感光体や現像ローラが自転しながら、ユニット全体が公転する構成のため、現像器内ではトナーが一時的に現像ローラや供給ローラとも接触、離脱する状況が発生し、現像初期に於いて帯電の立ち上がり性が悪いと、地カブリの原因となる。
【０１３５】
また、像形成ユニットが回転することによりトナーが上下に激しく移動するためシール部分からのトナーのこぼれが発生しやすく、そのためシール部分ではよりシールを強化する必要があり、融着現象が発生し、それが塊となって黒筋、白筋の画像ノイズの原因となる。
【０１３６】
また、感光体上からクリーニングされ、感光体上から回収された廃トナーが再度感光体に繰り返し付着離脱する状況が必ず発生する。その廃トナーが感光体と再度繰り返し接触、離脱することで感光体へのフィルミングが著しく発生しやすくなり、感光体の寿命低下の要因となる。
【０１３７】
そこで、本形態のトナーの使用により、トナーの帯電の立上がり性が安定化し、均一な帯電性を有し、現像初期の地カブリ発生を抑えることができる。樹脂中での均一分散性の向上、良好な帯電性、材料の有する離型性のため、像形成ユニットでの、融着現象や黒筋、白筋の画像ノイズの発生はみられない。また廃トナーが感光体と再度繰り返し接触離脱による感光体へのフィルミングの発生は防止可能である。
【０１３８】
また、本形態では、像担持体と導電性弾性ローラとの間に転写材を挿通させ、前記導電性弾性ローラに転写バイアス電圧を付与することにより前記像担持体上にあるトナー画像を静電気力で転写材に転写するトナー転写システムを具備する電子写真装置に好適に使用される。これは、かかるトナー転写システムは、接触転写であることから、電気力以外の機械力が転写に作用して、本来転写されるべきでない感光体表面に付着した逆極性トナーが転写されたり、通紙していない状態で感光体表面に付着したトナーが転写ローラ表面を汚染し、転写紙裏面を汚染させてしまうことがあるものである。
【０１３９】
そこで、本形態のトナーの使用により、トナーの凝集を抑え、過帯電を防止し、帯電性の安定化が得られ、転写時の中抜けを防止できるとともに高転写効率を得ることが可能となる。また転写体や、感光体へのフィルミングの発生を防止でき、また転写紙の不要トナー粒子による汚染を防止することができる。また、転写ローラ表面上の傷やフィルミングも防止でき、画像欠陥も防止することができる。
【０１４０】
また、本形態では、転写プロセス後に感光体上に残留したトナーをクリーニングにより回収するクリーニングプロセス工程を有さずに、次の帯電、露光、現像プロセスを行うクリーナーレスプロセスを基本構成とする電子写真装置に好適に使用される。
【０１４１】
本形態のトナーの使用により、トナーの凝集を抑え、過帯電を防止し、帯電性の安定化が得られ、高転写効率を得ることが可能となる。また樹脂中での均一分散性の向上、良好な帯電性、材料の有する離型性により、非画像部に残留したトナーの現像での回収が良好に行える。そのため、非画像部の前の画像パターンが残る現像メモリーも発生もない。
【０１４２】
また、本形態では、トナーを定着する手段にベルト式の定着媒体を使用する構成の定着プロセスを具備する電子写真装置に好適に使用される。そのベルトとしては耐熱性と変形自在性とを有するニッケル電鋳ベルトやポリイミドベルトの耐熱ベルトが用いられる。離形性を向上するために表面層としてシリコーンゴム、フッ素ゴム、フッ素樹脂を用いる構成である。これらの定着ベルトにおいてはこれまでは離型オイルを塗布してオフセットを防止してきた。オイルを使用せずに離型性を有するトナーにより、離型オイルを塗布する必要はなくなった。しかし離型オイルを塗布しないと帯電しやすく、未定着のトナー像がベルトと近接すると帯電の影響により、トナー飛びが生じる場合がある。特に低温低湿下において発生しやすい。またトナーが高温オフセット防止のため一定以上の高分子量成分を付加し、ある程度の弾性要素を持たせたとき、トナーの細い縦線のパターンを描いた紙が曲率の大きいベルトからの隔離時に先端部がベルトに持っていかれる先端オフセットが生じる場合がある。また従来の剛性の定着ローラと比べて弾性体のベルト式では、オイルレスにより傷による寿命低下が問題となる。
【０１４３】
そこで、本形態のトナーの使用により、オイルを使用せずともオフセットの発生を防止でき、カラー高透光性を得ることができる。またトナーの過帯電性を抑制できベルトとの帯電作用によるトナーの飛びを抑えられる。またベルトからの隔離時に先端部がベルトに持っていかれるオフセットトナーの分子量分布と滑性の効果により防止することが可能となる。
【０１４４】
また、本形態に使用される顔料としては、カーボンブラック、鉄黒、グラファイト、ニグロシン、アゾ染料の金属錯体、、Ｃ．Ｉ．ピグメント・イエロー１，３，７４，９７，９８等のアセト酢酸アリールアミド系モノアゾ黄色顔料、Ｃ．Ｉ．ピグメント・イエロー１２，１３，１４，１７等のアセト酢酸アリールアミド系ジスアゾ黄色顔料、Ｃ．Ｉ．ソルベントイエロー１９，７７，７９、Ｃ．Ｉ．ディスパース・イエロー１６４、Ｃ．Ｉ．ピグメント・レッド４８，４９：１，５３：１，５７，５７：１，８１，１２２，５等の赤色顔料、Ｃ．Ｉ．ソルベント・レッド４９，５２，５８，８等の赤色染料、Ｃ．Ｉ．ピグネント・ブルー１５：３等のフタロシアニン及びその誘導体の青色染顔料が１種又は２種類以上で配合される。添加量は結着樹脂１００重量部に対し、３〜８重量部が好ましい。
【０１４５】
さらに、トナーの体積平均粒径は３〜１１μｍで、好ましくは３〜９μｍ、より好ましくは３〜６μｍである。１１μｍより大きいと、解像度が低下し高画質が得らず、３μｍより小さいと、トナーの凝集が強くなり地カブリが増大する。
【０１４６】
定着助剤の体積平均粒径は１〜１０μｍで、好ましくは２〜８μｍ、より好ましくは２〜５μｍである。
【０１４７】
またトナーの体積粒径分布の変動係数が１５〜３５％、個数粒径分布の変動係数が２０〜４０％であることが好ましい。より好ましくは、体積粒径分布の変動係数が１５〜３０％、個数粒径分布の変動係数が２０〜３５％、さらに好ましくは、体積粒径分布の変動係数が１５〜２５％、個数粒径分布の変動係数が２０〜３０％である。
【０１４８】
変動係数とはトナーの粒径における標準偏差を平均粒径で割ったものである。コールターカウンタ（コールター社）を使用して測定した粒子径をもとにしたものである。標準偏差は、n個の粒子系の測定を行なった時の、各測定値の平均値からの差の２乗を（ｎ−１）で割った値の平方根であらわされる。
【０１４９】
つまり変動係数とは粒度分布の広がり具合をあわらしたもので、体積粒径分布の変動係数が１５％未満、又は個数粒径分布の変動係数が２０％未満となると、生産的に困難であり、コストアップの要因となる。体積粒径分布の変動係数が３５％より大、または個数粒径分布の変動係数が４０％より大きくなると、粒度分布がブロードとなるとトナーの凝集性が強くなり、感光体へのフィルミングが発生しやすくなる。
【０１５０】
トナーは予備混合処理、溶融混錬処理、粉砕分級処理、外添処理の工程を経て作成される。
【０１５１】
予備混合処理は、結着樹脂とこれに分散させるべき添加剤を撹拌羽根を具備したミキサなどにより均一分散する処理である。ミキサとしては、スーパーミキサ（川田製作所製）、ヘンシェルミキサ（三井三池工業製）、ＰＳミキサ（神鋼パンテック製）、レーディゲミキサ等の公知のミキサを使用する。
【０１５２】
図１にトナー溶融混練処理の概略斜視図を、図２に平面図、図３に正面図、図４に側面図を示す。６０１はトナー原料の定量供給機、６０２はロール（ＲＬ１）、６０３はロール（ＲＬ２）、６０４はロール（ＲＬ１）上に巻きついたトナーの溶融膜、６０２−１はロール（ＲＬ１）の前半部（原料の搬送方向の上流部）、６０２−２はロール（ＲＬ２）の後半部（原料の搬送方向の下流部）、６０５はロール（ＲＬ１）の前半部６０２−１を加熱するための熱媒体の流入口、６０６はロール（ＲＬ１）の前半部６０２−１を加熱した熱媒体の流出口、６０７はロール（ＲＬ１）の後半部６０２−２を加熱又は冷却するための媒体の流入口、６０８はロール（ＲＬ１）の後半部６０２−２を加熱又は冷却した媒体の流出口、６０９はロール（ＲＬ２）６０３を加熱又は冷却するための媒体の流入口、６１０はロール（ＲＬ２）６０３を加熱又は冷却した媒体の流出口、６１１はロール表面のスパイラル状の溝で深さは２〜１０ｍｍ程度、６１２はロール間で形成されるトナー溜りである。６１１の螺旋状の溝はトナーの混練時に材料が原料投入部の右端から排出部の左端にスムーズに搬送されるに好ましいものである。
【０１５３】
定量供給機から原料供給フィーダ６１３を伝わりながら開口部６１４からトナー原料が矢印６１５のようにロール（ＲＬ１）６０２−１側の端部付近に落下させる。供給フィーダの開口部の長さは６１６で表させる。この長さはロール半径の１／２〜４倍の長さが好ましい。短いと落下させる材料が溶融する前に２本のローラの隙間から下に落下する量が急増する。長すぎると原料フィーダでの搬送途中で原料が分離して均一な分散が得られない。
【０１５４】
また落下位置は図４の矢印にて図示するようにロール（ＲＬ１）６０２の２本のロールが最近接する点から２０°〜８０°の範囲の地点に落下させる。２０°よりも小さい角度であると２本のロールの隙間から落下する量が急増する。８０°以上であると落下させる際、トナー粉末の舞上りが多くなり周辺を汚染する。またカバー６１７は開口部長さ６１６よりも広い領域をカバーできるように設置する。図３ではカバーの図示は省略している。
【０１５５】
定量供給機６０１からトナー原料は供給フィーダ６１３を伝わりながら開口部６１４から落下する。落下したトナー原料はロール（ＲＬ１）６０２−１側の端部付近に投下される。そして６０２−１の熱とロール（ＲＬ２）６０３との圧縮せん断力により樹脂が溶融し、ロール（ＲＬ１）の前半部６０２−１に巻付くようになる。その状態がロール（ＲＬ１）の後半部６０２−２の端部にまで広がり、ロール（ＲＬ１）の前半部６０２−１よりも低い温度で加熱又は冷却されたロール（ＲＬ２）の後半部６０２−２からトナー魂として剥離される。なお、上記処理の間、ロール６０３は室温以下に冷却されている。ロール（ＲＬ１）６０２とロール（ＲＬ２）６０３のクリアランスは０．１〜０．９ｍｍである。本実施例では原料投入量は１０ｋｇ／ｈ、ロール（ＲＬ１）（ＲＬ２）の直径は１４０ｍｍ、長さは８００ｍｍで行った。
【０１５６】
得られたトナー塊を、カッターミルなどで粗粉砕し、その後ジェットミル粉砕（例えばＩＤＳ粉砕機、日本ニューマティック工業）などで細かく粉砕し、さらに必要に応じて気流式分級機で微粉粒子をカットして、所望の粒度分布のトナー粒子（トナー母体粒子）を得るものである。そして分級処理により３〜６μｍの範囲の体積平均粒子径を有するトナー粒子（トナー母体粒子）を所得する。
【０１５７】
外添処理は、前記分級により得られたトナー粒子（トナー母体粒子）にシリカなどの外添剤を混合する処理である。これにはヘンシェルミキサ、スーパーミキサなどの公知のミキサが使用される。
【０１５８】
次に、実施例により本発明を更に詳細に説明する。
【０１５９】
（表１）に実施例で使用する結着樹脂の特性を示す。樹脂はビスフェノールＡプロピルオキサイド付加物、テレフタル酸、トリメリット酸、コハク酸、フマル酸を主成分としたポリエステル樹脂を使用し、配合比、重合条件により熱特性を変えた樹脂を使用した。
【０１６０】
【表１】

【０１６１】
Ｍnｆは結着樹脂の数平均分子量、Ｍｗｆは結着樹脂の重量平均分子量、Ｍｚｆは結着樹脂のＺ平均分子量、Ｗｍｆは重量平均分子量Ｍｗｆと数平均分子量Ｍｎｆとの比Ｍｗｆ／Ｍｎｆ、Ｗｚｆは結着樹脂のＺ平均分子量Ｍｚｆと数平均分子量Ｍｎｆの比Ｍｚｆ／Ｍｎｆ、ＡＶは樹脂酸価を示す。
【０１６２】
（表２）（表３）に本実施例で使用する定着助剤及びその物性値を示す。
【０１６３】
【表２】

【０１６４】
【表３】

【０１６５】
（表４）に本実施例で使用する電荷制御剤を示す。
【０１６６】
サリチル酸誘導体の金属塩として、炭素数１〜１０のアルキル基としては例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基等が挙げられる。金属Ｙとしては亜鉛、ニッケル、コバルト、銅、クロムが挙げられ、亜鉛、クロムが好ましい。ベンジル酸誘導体の金属塩としては、Ｒ¹〜Ｒ⁴がベンゼン環、アルカリ金属Ｘとしてはリチウム、ナトリウム、カリウム等が挙げられ、カリウムが好ましい。
【０１６７】
【表４】

【０１６８】
（表５）に本実施例で使用する外添剤シリカを示す。シリカの帯電量はノンコートのフェライトキャリアとの摩擦帯電のブローオフ法により測定したものである。２５℃４５％ＲＨの環境下で、１００ｍｌのポリエチレン容器にキャリア５０ｇとシリカ等０．１ｇを混合し、縦回転にて１００ｍｉｎ^-1の速度で５分、３０分間攪拌した後、０．３ｇ採取し、窒素ガス１．９６×１０⁴（Ｐａ）で６０ｓｅｃブローした。
【０１６９】
正帯電性では５分間攪拌後の５分値が＋１００〜＋８００μＣ／ｇで、３０分間攪拌後の３０分の値が＋５０〜＋４００μＣ／ｇであることが好ましい。３０分値での帯電量が５分値での帯電量の４０％以上を維持しているシリカが好ましい。低下率が大きいと長期連続使用中での帯電量の変化が大きく、一定の画像を維持できなくなる。
【０１７０】
負帯電性では５分値が−１００〜−８００μＣ／ｇで、３０分の値が−５０〜−６００μＣ／ｇであることが好ましい。高い帯電量のシリカでは少量の添加量で機能を発揮できる。
【０１７１】
【表５】

【０１７２】
（表６）に本実施例で使用する顔料を示す。
【０１７３】
【表６】

【０１７４】
（表７）（表８）に本実施例での混練条件を示す。
【０１７５】
Ｔｍは結着樹脂の軟化点、Ｔｗは定着助剤の融点、Ｔｒｊ１（℃）はロール（ＲＬ１）の前半部の加熱温度、Ｔｒｋ１（℃）はロール（ＲＬ１）の後半部の加熱温度、Ｔｒ２（℃）ロール（ＲＬ２）の加熱温度、Ｒｗ１はロール（ＲＬ１）の回転数、Ｒｗ２はロール（ＲＬ２）の回転数、ロール（ＲＬ１）の回転時の負荷電流値をＤｒ１、ロール（ＲＬ２）の負荷電流値をＤｒ２と示している。
【０１７６】
【表７】

【０１７７】
【表８】

【０１７８】
（表９）に本実施例で使用したトナー材料組成を示す。なお、トナーサンプルＴＭ１，ＴＭ２，ＴＭ３，ＴＹ１，ＴＹ２，ＴＹ３，ＴＣ１，ＴＣ２，ＴＣ３，ＴＢ１，ＴＢ２及びＴＢ３は参考例である。
【０１７９】
【表９】

【０１８０】
それぞれのトナーの重量平均粒径は６〜７μｍ、体積粒径分布の変動係数が２０〜２５％、個数粒径分布の変動係数が２５〜３０％となるように試作した。
【０１８１】
顔料、電荷制御剤、定着助剤の配合量比は結着樹脂１００重量部に対する配合量（重量部）比を括弧内に示す。外添剤はトナー母体１００重量部に対する配合量（重量部）を示している。外添処理はＦＭ２０Ｂにおいて、攪拌羽根Ｚ０Ｓ０型、回転数２０００ｒｐｍ、処理時間５ｍｉｎ、投入量１ｋｇで行った。
【０１８２】
（表１０）（表１１）に本実施例で混練処理を施した後のトナーの分子量特性を示す。トナーはマゼンタトナーのＴＭトナーで評価した。イエロー、シアン、ブラックトナーでも同様な結果になる。Ｍｎｖはトナーの数平均分子量、Ｍｗｖはトナーの重量平均分子量、Ｗｍｖはトナーの重量平均分子量Ｍｗｖと数平均分子量Ｍｎｖの比Ｍｗｖ／Ｍｎｖ、ＷｚｖはトナーのＺ平均分子量Ｍｚｖと数平均分子量Ｍｎｖの比Ｍｚｖ／Ｍｎｖを示す。
【０１８３】
ＭＬは分子量分布において低分子量側の分子量極大ピークを示す分子量値、ＭＨは高分子量側の分子量極大ピークを示す分子量値、ＳｍはＨｂ／Ｈａ、ＳＫ１はＭ１０／Ｍ９０、ＳＫ２は（Ｍ１０−Ｍ９０）／Ｍ９０を示す。
【０１８４】
【表１０】

【０１８５】
【表１１】

【０１８６】
また図５〜１１に分子量分布特性を示す。
【０１８７】
図５ａ、図５ｂはそれぞれ結着樹脂ＰＥＳ−１、トナーＴＭ−１の分子量分布特性、 図６ａ、図６ｂはそれぞれ結着樹脂ＰＥＳ−２、トナーＴＭ−２の分子量分布特性、図７ａ、図７ｂはそれぞれ結着樹脂ＰＥＳ−３、トナーＴＭ−３の分子量分布特性、図８ａ、図８ｂはそれぞれ結着樹脂ＰＥＳ−４、トナーＴＭ−４の分子量分布特性、図９ａ、図９ｂはそれぞれ結着樹脂ｐｅｓ−５、トナーｔｍ−５の分子量分布特性を示す。
【０１８８】
結着樹脂ＰＥＳ−１では３×１０⁴以上の高分子量成分を結着樹脂分子量分布全体に対し面積比で５％以上存在している。また３×１０⁵〜９×１０⁶の高分子量成分を結着樹脂分子量分布全体に対し面積比で１％以上有している。同様にＰＥＳ−２、３、４も３×１０⁴以上の高分子量成分を結着樹脂分子量分布全体に対し面積比で５％以上存在している。また３×１０⁵〜９×１０⁶の高分子量成分を結着樹脂分子量分布全体に対し面積比で１％以上有している。しかしｐｅｓ−５では３×１０⁴以上の高分子量成分の存在は結着樹脂分子量分布全体に対し面積比で５％以下であり、また３×１０⁵〜９×１０⁶の高分子量成分は存在しない。
【０１８９】
混練によりトナーではそれが分子切断され、高分子成分側にピーク又はショルダーとなって現れていることが分かる。つまり透光性を阻害している成分が切断によりなくなり、高分子側に急峻な傾きとなってあらわれ、これが透光性を阻害せずに耐オフセット性を維持させている要因である。トナーＴＭ−１では３×１０⁵以上の高分子量成分量はトナー分子量分布全体に対し面積比で５％以下であり、１×１０⁶以上の高分子量成分はほとんど含有していない。同様にＴＭ−２、３、４も３×１０⁵以上の高分子量成分量はトナー分子量分布全体に対し面積比で５％以下であり、１×１０⁶以上の高分子量成分はほとんど含有していない。
【０１９０】
また図１０、図１１に分子量分布特性の一例を示す。図１１には高分子成分側に急峻な分子量ピークとなる特性のＭ１０、Ｍ９０を概略的に示している。分子量分布の極大ピークの高さを１００％としている。図１０はトナーＴＭ−３の分子量分布特性のＭ１０、Ｍ９０を概略的に示している。高分子成分側にはショルダー形状として現れており、このショルダー部の肩の頂点の高さを１００％の基準としている。これは結着樹脂ＰＥＳ３の高分子量成分が、混練により分子切断され、高分子成分側にショルダーとなって現れたためである。
【０１９１】
その高分子側の分布のピーク高さを１００％としたとき、極大ピーク又はショルダーに相当する分子量値よりも大きい領域にある分子量曲線、すなわちこの領域における分子量分布曲線の傾きが負となる部位、つまり分布曲線の右側の部位において、分子量分布の極大ピーク又はショルダーの高さを１００％とした場合に、分子量極大ピーク又はショルダーの高さの９０％に相当する分子量をＭ９０、分子量極大ピーク又はショルダーの高さの１０％に相当する分子量をＭ１０としている。ここで、Ｍ１０／Ｍ９０の値（分子量分布曲線の傾き）は、超高分子量成分の分子切断の状態を定量化できるものである。Ｍ１０／Ｍ９０の値が小さいということは分子量分布曲線の傾きが急峻であり、透光性を阻害している成分が切断によりなくなり、高透光性を有するわけである。さらには、この高分子側に現れるピ−クが耐オフセット性に寄与しているわけである。
【０１９２】
また図１６に定着助剤ＷＦ−１の分子量分布特性を示す。横軸は分子量の対数を取っている。
【０１９３】
（実施例１）
図１２は本実施例で使用したフルカラー画像形成用の電子写真装置の構成を示す断面図である。図１２において、１はカラー電子写真プリンタの外装筐で、図中の右端面側が前面である。１Ａはプリンタ前面板であり、この前面板１Ａはプリンタ外装筐１に対して下辺側のヒンジ軸１Ｂを中心に点線表示のように倒し開き操作、実線表示のように起こし閉じ操作自由である。プリンタ内に対する中間転写ベルトユニット２の着脱操作や紙詰まり時などのプリンタ内部点検保守等は前面板１Ａを倒し開いてプリンタ内部を大きく解放することにより行われる。この中間転写ベルトユニット２の着脱動作は、感光体の回転軸母線方向に対し垂直方向になるように設計されている。
【０１９４】
中間転写ベルトユニット２の構成を図１３に示す。中間転写ベルトユニット２はユニットハウジング２ａに、中間転写ベルト３、導電性弾性体よりなる第１転写ローラ４、アルミローラよりなる第２転写ローラ５、中間転写ベルト３の張力を調整するテンションローラ６、中間転写ベルト３上に残ったトナー像をクリーニングするベルトクリーナローラ７、クリーナローラ７上に回収したトナーをかきおとすスクレーパ８、回収したトナーを溜おく廃トナー溜め９ａおよび９ｂ、中間転写ベルト３の位置を検出する位置検出器１０を内包している。この中間転写ベルトユニット２は、図１２に示されているように、プリンタ前面板１Ａを点線のように倒し開いてプリンタ外装筐１内の所定の収納部に対して着脱自在である。
【０１９５】
中間転写ベルト３は、絶縁性樹脂中に導電性のフィラーを混練して押出機にてフィルム化して用いる。本実施例では、絶縁性樹脂としてポリカーボネート樹脂（たとえば三菱ガス化学製，ユーピロンＺ３００）９５重量部に、導電性カーボン（たとえばケッチェンブラック）５重量部を加えてフィルム化したものを用いた。また、表面に弗素樹脂をコートした。フィルムの厚みは約３５０μｍ、抵抗は約１０⁷〜１０⁹Ω・ｃｍである。ここで、中間転写ベルト３としてポリカーボネート樹脂に導電性フィラーを混練し、これをフィルム化したものを用いているのは、中間転写ベルト３の長期使用による弛みや，電荷の蓄積を有効に防止できるようにするためであり、また、表面をフッ素樹脂でコートしているのは、長期使用による中間転写ベルト表面へのトナーフィルミングを有効に防止できるようにするためである。
【０１９６】
この中間転写ベルト３を、厚さ１００μｍのエンドレスベルト状の半導電性のウレタンを基材としたフィルムよりなり、周囲に１０⁶〜１０⁸Ω・cmの抵抗を有するように低抵抗処理をしたウレタンフォームを成形した第１転写ローラ４、第２転写ローラ５およびテンションローラ６に巻回し、矢印方向に移動可能に構成する。ここで、中間転写ベルト３の周長は、最大用紙サイズであるＡ４用紙の長手方向の長さ（２９８ｍｍ）に、後述する感光体ドラム（直径３０ｍｍ）の周長の半分より若干長い長さ（６２ｍｍ）を足した３６０ｍｍに設定している。
【０１９７】
中間転写ベルトユニット２がプリンタ本体に装着されたときには、第１転写ローラ４は、中間転写ベルト３を介して感光体１１（図１３に図示）に約９．８×１０⁴（Ｎ／ｍ²）の力で圧接され、また、第２転写ローラ５は、中間転写ベルト３を介して上記の第１転写ローラ４と同様の構成の第３転写ローラ１２（図１３に図示）に圧接される。この第３転写ローラ１２は中間転写ベルト３に従動回転可能に構成している。
【０１９８】
クリーナローラ７は、中間転写ベルト３を清掃するベルトクリーナ部のローラである。これは、金属性のローラにトナーを静電的に吸引する交流電圧を印加する構成である。なお、このクリーナローラ７はゴムブレードや電圧を印加した導電性ファーブラシであってもよい。
【０１９９】
図１２において、プリンタ中央には黒、シアン、マゼンタ、イエロの各色用の４組の扇型をした像形成ユニット１７Ｂｋ、１７Ｙ、１７Ｍ、１７Ｃが像形成ユニット群１８を構成し、図のように円環状に配置されている。各像形成ユニット１７Ｂｋ、１７Ｙ、１７Ｍ、１７Ｃは、プリンタ上面板１Ｃをヒンジ軸１Ｄを中心に開いて像形成ユニット群１８の所定の位置に着脱自在である。像形成ユニット１７Ｂｋ、１７Ｙ、１７Ｍ、１７Ｃはプリンタ内に正規に装着されることにより、像形成ユニット側とプリンタ側の両者側の機械的駆動系統・電気回路系統が相互カップリング部材（不図示）を介して結合して機械的・電気的に一体化する。
【０２００】
円環状に配置されている像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙは支持体（図示せず）に支持されており、全体として移動手段である移動モータ１９に駆動され、固定されて回転しない円筒状の軸２０の周りに回転移動可能に構成されている。各像形成ユニットは、回転移動によって順次前述の中間転写ベルト３を支持する第２転写ローラ４に対向した像形成位置２１に位置することができる。像形成位置２１は信号光２２による露光位置でもある。
【０２０１】
各像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙは、中に入れた現像剤を除きそれぞれ同じ構成部材よりなるので、説明を簡略化するため黒用の像形成ユニット１７Ｂｋについて説明し、他色用のユニットの説明については省略する。
【０２０２】
図１４に像形成ユニットを示す。１１は感光体、３０はＪＩＳ−Ａ硬度６０°のシリコーンゴムよりなるφ１８ｍｍの現像ロ−ラで、感光体に２１Ｎの力で圧接され、矢印の方向に回転する。３１はφ１４ｍｍのウレタンスポンジよりなる供給ローラで、トナーホッパ内のトナーを現像ローラに供給する。３２は金属製のブレードで現像ローラ上にトナーの層を形成する。３３は電源で２３０Ｖの直流と、５００Ｖ（ｐ−ｐ）、周波数１ｋＨｚの交流電圧が印可される。２４はエピクロルヒドリンゴムよりなるφ１２ｍｍの帯電ローラで直流バイアス−１ｋＶが印加される。感光体表面をー４５０Ｖに帯電する。２６は現像剤溜め、３４はクリーナ、２７は廃トナー、２８Ｂｋはブラックトナーである。
【０２０３】
図１２の３５はプリンタ外装筐１内の下側に配設したレーザビームスキャナ部であり、図示しない半導体レーザ、スキャナモータ３５ａ、ポリゴンミラー３５ｂ、レンズ系３５ｃなどから構成されている。このレーザビームスキャナ部３５からの画像情報の時系列電気画素信号に対応した画素レーザ信号光２２は、像形成ユニット１７Ｂｋと１７Ｙの間に形成された光路窓口３６を通って、軸２０の一部に開けられた窓３７を通して軸２０内の固定されたミラー３８に入射し、反射されて像形成位置２１にある像形成ユニット１７Ｂｋの露光窓２５から像形成ユニット１７Ｂｋ内にほぼ水平に進入し、像形成ユニット内に上下に配設されている現像剤溜め２６とクリーナ３４との間の通路を通って感光体１１の左側面の露光部に入射し母線方向に走査露光される。
【０２０４】
ここで光路窓口３６からミラー３８までの光路は両隣の像形成ユニット１７Ｂｋと１７Ｙとのユニット間の隙間を利用しているため、像形成ユニット群１８には無駄になる空間がほとんど無い。また、ミラー３８は像形成ユニット群１８の中央部に設けられているため、固定された単一のミラーで構成することができ、シンプルでかつ位置合わせなどが容易な構成である。
【０２０５】
１２はプリンタ前面板１Ａの内側で紙給送ローラ３９の上方に配設した第３転写ローラであり、中間転写ベルト３と第３転写ローラ１２との圧接されたニップ部には、プリンタ前面板１Ａの下部に設けた紙給送ローラ３９により用紙が送られてくるように用紙搬送路が形成されている。
【０２０６】
４０はプリンタ前面板１Ａの下辺側に外方に突出させて設けた給紙カセットであり、複数の紙Ｓを同時にセットできる。４１ａと４１ｂとは紙搬送タイミングローラ、４２ａは定着ローラ、４２ｂは加圧ローラ、４２ｃはフッ素ゴムからなる定着ベルト、４２ｄは加熱媒体ローラ、４３は第３転写ローラ１２と定着ローラ対間に設けた紙ガイド板、４４ａ・４４ｂは定着ローラ対の紙出口側に配設した紙排出ローラ対である。
【０２０７】
図１５にその定着プロセスを示す。定着ローラ４２ａとヒートローラ４２ｄとの間にベルト４２ｃがかけられている。定着ローラ４２ａと加圧ローラ４２ｂとの間に所定の加重がかけられており、ベルトと加圧ローラとの間でニップが形成される。ヒートローラ４２ｄの内部にはヒータが設けられ、外面には温度センサー５１が配置されている。
【０２０８】
加圧ローラ４２ｂは加圧バネ５２により定着ローラ４２ａに押しつけられている。トナー５３を有する記録材５４は、案内板５５に沿って動く。
【０２０９】
定着部材としての定着ローラ４２ａは、長さが２５０ｍｍ、外径が１４ｍｍ、厚さ１ｍｍのアルミニウム製中空ローラ芯金５６の表面に、ＪＩＳ規格によるゴム硬度（ＪＩＳ−Ａ）が２０度のシリコーンゴムからなる厚さ３ｍｍの弾性層５７を設けている。この上にシリコーンゴム層５８が３ｍｍの厚みで形成され外径が約２０ｍｍとなっている。図示しない駆動モータから駆動力を受けて１００ｍｍ／ｓで回転する。
【０２１０】
ヒートローラ４２ｄは肉厚１ｍｍ、外径２０ｍｍのアルミニウムの中空パイプからなっている。内部に加熱用の７００Ｗのランプヒータ５８を有し、定着ローラ表面温度はサーミスタを用いて表面温度１７０度に制御した。また、ＯＨＰ画像定着の際は５０ｍｍ／ｓと半速での定着を行った。
【０２１１】
加圧部材としての加圧ローラ４２ｂは、長さが２５０ｍｍ、外径２０ｍｍである。これは外径１６ｍｍ、厚さ１ｍｍのアルミニウムからなる中空ローラ芯金５９の表面にＪＩＳ規格によるゴム硬度（ＪＩＳ−Ａ）が５５度のシリコーンゴムからなる厚さ２ｍｍの弾性層６０を設けている。この加圧ローラ４２ｂは、回転可能に設置されており、片側１４７Ｎのバネ加重のバネ５２によって定着ローラ１との間で幅５．０ｍｍのニップ幅を形成している。
【０２１２】
各像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙ、中間転写ベルトユニット２には、廃トナー溜めを設けている。
【０２１３】
以下、動作について説明する。
【０２１４】
最初、像形成ユニット群１８は、図１２に示すように、黒の像形成ユニット１７Ｂｋが像形成位置２１にある。このとき感光体１１は中間転写ベルト３を介して第１転写ローラ４に対向接触している。
【０２１５】
像形成工程により、レーザビームスキャナ部３５により黒の信号光が像形成ユニット１７Ｂｋに入力され、黒トナーによる像形成が行われる。このとき像形成ユニット１７Ｂｋの像形成の速度（感光体の周速に等しい６０ｍｍ／ｓ）と中間転写ベルト３の移動速度は同一になるように設定されており、像形成と同時に第１転写ローラ４の作用で、黒トナー像が中間転写ベルト３に転写される。このとき第１転写ローラには＋１ｋＶの直流電圧を印加した。黒のトナー像がすべて転写し終わった直後に、像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙは像形成ユニット群１８として全体が移動モータ１９に駆動されて図中の矢印方向に回転移動し、ちょうど９０度回転して像形成ユニット１７Ｃが像形成位置２１に達した位置で止まる。この間、像形成ユニットの感光体以外のトナーホッパ２６やクリーナ３４の部分は感光体１１先端の回転円弧より内側に位置しているので、中間転写ベルト３が像形成ユニットに接触することはない。
【０２１６】
像形成ユニット１７Ｃが像形成位置２１に到着後、前と同様に今度はシアンの信号でレーザビームスキャナ部３５が像形成ユニット１７Ｃに信号光２２を入力しシアンのトナー像の形成と転写が行われる。このときまでに中間転写ベルト３は一回転し、前に転写された黒のトナー像に次のシアンのトナー像が位置的に合致するように、シアンの信号光の書き込みタイミングが制御される。この間、第３転写ローラ１２とクリーナローラ７とは中間転写ベルト３から少し離れており、転写ベルト上のトナー像を乱さないように構成されている。
【０２１７】
以上と同様の動作を、マゼンタ、イエロについても行い、中間転写ベルト３上には４色のトナー像が位置的に合致して重ね合わされカラー像が形成された。最後のイエロトナー像の転写後、４色のトナー像はタイミングを合わせて給紙カセット４０から送られる用紙に、第３転写ローラ１２の作用で一括転写される。このとき第２転写ローラ５は接地し、第３転写ローラ１２には＋１．５ｋＶの直流電圧を印加した。用紙に転写されたトナー像は定着ローラ対４２ａ・４２ｂにより定着された。用紙はその後排出ローラ対４４ａ・４４ｂを経て装置外に排出された。中間転写ベルト３上に残った転写残りのトナーは、クリーナローラ７の作用で清掃され次の像形成に備えた。
【０２１８】
次に単色モード時の動作を説明する。単色モード時は、まず所定の色の像形成ユニットが像形成位置２１に移動する。次に前と同様に所定の色の像形成と中間転写ベルト３への転写を行い、今度は転写後そのまま続けて、次の第３転写ローラ１２により給紙カセット４０から送られてくる用紙に転写をし、そのまま定着した。
【０２１９】
（表１２）に図１２の電子写真装置により、画像出しを行った結果を示す。
【０２２０】
【表１２】

【０２２１】
かかる電子写真装置により、前記のように製造したトナーを用いて画像出しを行ったところ、横線の乱れやトナーの飛び散り、文字の中抜けなどがなくベタ黒画像が均一で、１６本／ｍｍの画線をも再現した極めて高解像度高画質の画像が得られ、画像濃度１．３以上の高濃度の画像が得られた。また、非画像部の地かぶりも発生していなかった。更に、１万枚の長期耐久テストにおいても、流動性、画像濃度とも変化が少なく安定した特性を示した。また現像時の全面ベタ画像を取ったときの均一性も良好であった。現像メモリーも発生していない。また転写においても中抜けは実用上問題ないレベルであり、転写効率は９０％であった。また、感光体、中間転写ベルトへのトナーのフィルミングも実用上問題ないレベルであった。中間転写ベルトのクリーニングのスクレープ不良も未発生であった。また定着時のトナーの乱れやトナー飛びもほとんど生じていない。またクリーニングブレードを使用せずに転写時の残トナーをこのまま現像での回収を行うクリーナプロセスにおいても、回収がスムーズに行え、前画像の履歴が残ることがなかった。しかしｔｍ５、ｔｙ５、ｔｃ５のトナーは感光体のフィルミングや転写中抜けが発生し、カブリも多く発生した。中間転写ベルトのフィルミングや、クリーニングのスクレープ不良も発生した。現像時の全面ベタ画像を取ったときに後半部にかすれが生じた。定着時にトナーのトナー飛びが発生した。
【０２２２】
次に（表１３）にＯＨＰ用紙に付着量１．２ｇ／ｃｍ²以上のベタ画像をプロセス速度は１１０ｍｍ／ｓ、オイルを塗布しないベルトを用いた定着装置にて非オフセット性試験を行った。定着ニップ部でＯＨＰのジャムは発生しなかった。普通紙の全面ベタグリーン画像では、オフセットは１２２０００枚目までは全く発生しなかった。シリコン又はフッ素系の定着ベルトでオイルを塗布せずともベルトの表面劣化現象はみられない。
【０２２３】
透過率と、高温でのオフセット性を評価した。プロセス速度は５５ｍｍ／ｓで、１８０℃で透過率は分光光度計Ｕ−３２００（日立製作所）で、７００ｎｍの光の透過率を測定した。定着性、耐オフセット性、保存安定性の結果を示す。
【０２２４】
【表１３】

【０２２５】
ＯＨＰ透光性が８０％以上を示しており、また非オフセット温度幅も４０〜６０Ｋとオイルを使用しない定着ローラにおいて良好な定着性を示した。また６０℃、５時間の保存安定性においても凝集はほとんど見られなかった。しかしｔｍ５のトナーは貯蔵安定性テストで固まりが生じ、また非オフセット温度域も狭い結果となった。
【０２２６】
【発明の効果】
以上のように、本発明によれば、ＧＰＣ（ゲル浸透クロマトグラフィー）における分子量分布において、重量平均分子量が１０００〜６０００、Ｚ平均分子量が１５００〜９０００、重量平均分子量と数平均分子量の比（重量平均分子量／数平均分子量）が１．１〜３．８、Ｚ平均分子量と数平均分子量の比（Ｚ平均分子量／数平均分子量）が１．５〜６．５、１×１０³〜１×１０⁴の領域に少なくとも一つの分子量極大ピークを有し、少なくとも炭素数５〜１００の長鎖アルキルアルコール、不飽和多価カルボン酸又はその無水物及び炭化水素系ワックスとの反応により得られ、酸価５〜８０ｍｇＫＯＨ／ｇ、融点９０〜１２０℃、２５℃における針入度が４以下である定着助剤と電荷制御剤としてサリチル酸誘導体の金属塩又はベンジル酸誘導体の金属塩を併用して結着樹脂に添加する構成により、接触式の一成分現像法に使用してもトナーの熱融着や凝集を生じず、長期連続使用での過帯電による画像濃度低下、低温低湿下でのカブリを防止することができ、均一な帯電分布を有し、長期使用しても安定した画像特性を出力し続けることが可能となる。
【０２２７】
導電性弾性ローラや、中間転写体を用いた電子写真方法で転写時の中抜けや飛び散りを防止し、高転写効率を得ることが可能となる。高湿下での長期使用においても、感光体、中間転写体のフィルミングを防止することができる。中間転写体のクリーニング性を向上することができる。クリーニングブレードを使用しないクリーニングプロセスにおいても転写残トナーの回収がスムーズに行え、前画像の履歴が残らないようにすることができる。
【０２２８】
シリコン又はフッ素系の定着手段（ローラやベルト）でオイルを塗布せずとも、高いＯＨＰ透光性を維持しながらオフセット性を防止できる。また長期使用してもベルトの表面劣化現象を生じることなく、良好な非オフセット性を維持させることができる。
【図面の簡単な説明】
【図１】本発明の実施例で使用したトナー溶融混練処理の概略斜視図
【図２】本発明の実施例で使用したトナー溶融混練処理の平面図
【図３】本発明の実施例で使用したトナー溶融混練処理の正面図
【図４】本発明の実施例で使用したトナー溶融混練処理の断面図
【図５】本発明の実施例の結着樹脂及びトナーの分子量分布特性を示す図
【図６】本発明の実施例の結着樹脂及びトナーの分子量分布特性を示す図
【図７】本発明の実施例の結着樹脂及びトナーの分子量分布特性を示す図
【図８】本発明の実施例の結着樹脂及びトナーの分子量分布特性を示す図
【図９】本発明の実施例の結着樹脂及びトナーの分子量分布特性を示す図
【図１０】本発明の実施例のトナーの分子量分布特性を示す図
【図１１】本発明の実施例のトナーの分子量分布特性を示す図
【図１２】本発明の実施例で使用した電子写真装置の構成を示す断面図
【図１３】本発明の実施例で使用した中間転写ベルトユニットの構成を示す断面図
【図１４】本発明の実施例で使用した現像ユニットの構成を示す断面図
【図１５】本発明の実施例で使用した定着ユニットの構成を示す断面図
【図１６】本発明の実施例の定着助剤の分子量分布特性を示す図
【符号の説明】
２ 中間転写ベルトユニット
３ 中間転写ベルト
４ 第１転写ローラ
５ 第２転写ローラ
６ テンションローラ
１１ 感光体
１２ 第３転写ローラ
１７Ｂｋ，１７Ｃ，１７Ｍ，１７Ｙ 像形成ユニット
１８ 像形成ユニット群
２１ 像形成位置
２２ レーザ信号光
３５ レーザビームスキャナ部
３８ ミラー
６０２ ロール（ＲＬ１）
６０３ ロール（ＲＬ２）
６０４ ロール（ＲＬ１）上に巻きついたトナーの溶融膜
６０５ 熱媒体の流入口
６０６ 熱媒体の流出口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner used in a copying machine, a laser printer, plain paper FAX, a color PPC, a color laser printer and a color FAX, and an electrophotographic apparatus.
[0002]
[Prior art]
In recent years, electrophotographic apparatuses are shifting from the purpose of office use to personal use, and there is a demand for technology that realizes downsizing, maintenance-free, and the like. Therefore, conditions such as good maintainability such as recycling of waste toner and less ozone exhaust are required.
[0003]
The printing process of electrophotographic copying machines and printers will be described. First, an image carrier (hereinafter referred to as a photoreceptor) is charged for image formation. As a charging method, a photoreceptor using a conventionally used corona charger, or a contact-type charging method in which a conductive roller is directly pressed against the photoreceptor in recent years with the aim of reducing the amount of ozone generated. There is a method for uniformly charging the surface. In the case of a copying machine, after charging the photosensitive member, the copy original is irradiated with light and the reflected light is irradiated onto the photosensitive member through the lens system. Alternatively, in the case of a printer, an image signal is sent to a light emitting diode or laser diode as an exposure light source, and a latent image is formed on the photosensitive member by turning on and off the light. When a latent image (surface potential level) is formed on the photoconductor, the photoconductor is visualized with toner (diameter of about 3 μm to 12 μm) that is a pre-charged colored powder. The toner adheres to the surface of the photoconductor according to the level of the surface potential of the photoconductor and is electrically transferred to a copy sheet. That is, the toner is charged positively or negatively in advance, and is electrically attracted by applying a charge having a polarity opposite to the toner polarity from the back surface of the copy paper. As a transfer method, a transfer method using a conventionally used corona discharger, or a transfer method in which a conductive roller is directly pressed against a photoconductor in order to reduce the amount of ozone generated has been put into practical use. At the time of transfer, not all of the toner on the photoreceptor is transferred to the copy sheet, but a part of the toner remains on the photoreceptor. This residual toner is scraped off by a cleaning blade or the like at the cleaning unit to become waste toner. The toner transferred to the copy paper is fixed to the paper by heat and pressure in the fixing process.
[0004]
As a fixing method, there are a pressure fixing method for passing between two or more metal rolls, an oven fixing method for passing through a heating atmosphere by an electric heater, and a hot roll fixing method for passing between heating rollers. In the heat roll fixing method, since the surface of the heating roller and the toner surface on the copy paper are in pressure contact, the thermal efficiency when fusing the toner image to the copy paper is good, and the fixing can be performed quickly. However, in the heat roll fixing method, the toner is brought into pressure contact with the surface of the heating roller in a heated and melted state, so that a part of the toner adheres to the surface of the roller and again adheres to the copy paper, which tends to cause an offset phenomenon. As a method for preventing the offset, the surface of the heating roller is formed of a heat-resistant fluororesin or silicone rubber having a good releasability with respect to the toner, and further, an anti-offset liquid such as silicone oil is supplied to the surface to form a thin liquid film. A method of coating the roller surface has been taken. In this method, a liquid such as silicone oil is heated to generate an odor, and an extra device for supplying the liquid is required, which complicates the mechanism of the copying apparatus. Also, in order to prevent offset with high stability, it is necessary to control the supply of liquid with high accuracy, and the copying apparatus must be expensive. Therefore, there is a demand for a toner that does not cause an offset even if such a liquid is not supplied and that can provide a good fixed image.
[0005]
As is well known, toners for electrostatic charge development used in electrophotographic methods are generally resin components, coloring components composed of pigments or dyes, plasticizers, charge control agents, and if necessary, release agents. It is comprised by the additional component. As the resin component, natural or synthetic resins may be used alone or mixed in a timely manner.
[0006]
Then, the above additives are premixed at an appropriate ratio, heated and kneaded by heat melting, finely pulverized by an airflow type impact plate method, and finely classified to complete a toner base. Thereafter, an external additive is added to the toner base to complete the toner. In one-component development, the toner is composed only of toner, but a two-component developer can be obtained by mixing with toner and a carrier made of magnetic particles.
[0007]
As a mold release agent, JP-A-2-266372 discloses the use of a free fatty acid type carnauba wax and / or montan ester wax, an oxidized rice wax having an acid value of 10-30, and JP-A-9-281748 discloses. , Melting point 85-100 ° C., vinyl copolymer polymerized in the presence of natural gas Fischer-Tropsch wax, Japanese Patent Application Laid-Open No. 10-327196 discloses a polyhydric alcohol component, a dicarboxylic acid, and a trivalent or higher polyvalent It is disclosed that a carboxylic acid compound is subjected to polycondensation, and an average dispersion particle size of a release agent is 0.1 to 3 μm, a particle size of an external additive is 4 to 200 nm, and 1 to 5 parts by weight are added. Japanese Patent Laid-Open No. 5-333584 discloses a content in which the fixability is improved by a constitution containing a fluorine-modified polyolefin resin such as polypropylene modified with an organic fluorine compound such as perfluorooctyl methacrylate. . In JP-A-5-188632, the softening point is 80 to 140 ° C., low molecular weight polyolefin containing fluorine, and a non-offset property at the time of fixing can be obtained by blending a molten mixture of low molecular weight olefin and polytetrafluoroethylene. The content to be improved is disclosed, and the content that is effective in improving the fixing property is described.
[0008]
In JP-A-59-148067, a softening point is specified by using an unsaturated ethylene polymer having a low molecular weight and a high molecular weight portion in the resin and defining a low molecular weight peak value and Mw / Mn. Toners containing such polyolefins are disclosed. As a result, fixing property and offset resistance are ensured. JP-A-56-158340 discloses a toner mainly composed of a resin comprising a specific low molecular weight polymer component and a high molecular weight polymer component. The purpose is to secure the fixing property by the low molecular weight component and ensure the offset resistance by the high molecular weight component. JP-A-58-223155 discloses a resin composed of an unsaturated ethylene polymer having a maximum value in a molecular weight region of 1000 to 10,000 and 200,000 to 1,000,000 and Mw / Mn of 10 to 40 and a specific softening. Toners containing polyolefins with dots are disclosed. It is used for the purpose of securing fixability with a low molecular weight component and ensuring offset resistance with a high molecular weight component and polyolefin.
[0009]
JP-A-63-56659 and JP-A-2000-98661 disclose toners relating to polyester resins, and disclose that good fixability can be obtained.
[0010]
As a charge control agent for imparting chargeability to the toner, a toner using a metal salt of a benzylic acid derivative is disclosed in JP-A-2-221967, JP-A-7-84409, JP-A-5-72812, This is disclosed in Japanese Laid-Open Patent Publication No. 5-165257. JP-A-53-127726, JP-A-55-42752, JP-A-7-221797 and the like disclose toners using metal salts of salicylic acid derivatives.
[0011]
[Problems to be solved by the invention]
Recently, from the viewpoint of protecting the global environment, it is possible to reduce the amount of ozone generated, to recycle waste toner that has not been reused in the past to regulate unlimited disposal of industrial waste, and to reduce the power consumption of fixing. There is a need for low-temperature fixing methods that can be suppressed. Toner materials are also being improved to cope with a roller transfer method with less ozone generation, waste toner recycling, and low-temperature fixing. Further, high-performance toners that can be satisfied at the same time, not individually, are an important issue for environmental protection.
[0012]
In the fixing process, it is necessary to improve the translucency by melting and mixing color toners in a color image. When toner melting failure occurs, light scattering occurs on the surface or inside of the toner image, and the original color tone of the toner dye is impaired. In addition, in the overlapping portion, light does not enter the lower layer and color reproducibility is deteriorated. Therefore, it is a necessary condition that the toner has a complete melting characteristic and a translucency that does not disturb the color tone. In particular, the need for light transmission on OHP paper is increasing due to an increase in the number of color presentation opportunities.
[0013]
However, the resin composition having sharp melt melting characteristics due to the light transmissibility decreases the offset resistance and causes offset by adhering to the surface of the fixing roller, so a large amount of oil or the like must be applied to the fixing roller. , Handling and equipment configuration become complicated. Therefore, an oil-less color fixing configuration that does not require oil is required.
[0014]
In addition, when a silicone material or a fluorine material having a strong negative charge is used for the fixing roller, an image disturbance in which an unfixed toner image electrostatically repels the fixing roller is liable to occur before entering the fixing portion. On the contrary, there is a case where the toner flies to the fixing roller before entering the fixing nip portion, thereby causing a halftone offset. In particular, the charging effect is likely to occur in a configuration in which the release oil is not applied. In addition, in a toner to which a release agent is added for the purpose of improving the offset property, the fixing roller is liable to be damaged due to a poorly dispersed state of the internal additive, which causes generation of vertical stripes in the image.
[0015]
Further, for the purpose of flexibility and downsizing of the apparatus and shortening of warm-up, a belt fixing method in which a medium heating unit and a toner melting and fixing unit are separately used is being used. Accordingly, the fixing roller can be reduced in diameter to reduce the size of the apparatus. Further, since the curvature of the paper discharge section is increased, the paper is hardly wound around the belt. Warm-up is shortened due to the low heat capacity of the belt. However, when the toner is added with a certain high molecular weight component to prevent high temperature offset and has a certain amount of elastic element, the paper with a thin vertical line pattern of the toner is separated from the belt with a large curvature when separated from the belt. There may be a tip offset where the part is brought to the belt.
[0016]
In order to increase the fixing strength on a high-speed machine, if a resin whose melt viscosity of the binder resin is lowered or whose molecular weight is lowered is used, a so-called spent that causes the toner to adhere to the carrier during long-term use occurs. It becomes easy. The stress resistance of the developer decreases. Further, when used in a low speed machine, an offset in which toner adheres to the heat roller during fixing tends to occur. Further, blocking occurs in which the toners are fused during long-term storage.
[0017]
Depending on the blending of high and low molecular weight components, it is possible to achieve both fixing strength and offset resistance for a narrow range of process speeds, but it is difficult to accommodate a wide range of process speeds. . In order to cope with a wide range of process speeds, a certain degree of effect can be exhibited by configuring a higher molecular weight component and a lower low molecular weight component. However, the fixing strength can be increased by increasing the low molecular weight component in the high speed machine, but the offset resistance is deteriorated, and the effect of increasing the offset resistance can be obtained by increasing the high molecular weight component in the low speed machine. If the amount of the high molecular weight component is increased, adverse effects such as a decrease in the pulverization property of the toner and a decrease in productivity occur.
[0018]
A low melting point release agent, such as polyethylene, polypropylene wax, ester wax, hydrocarbon wax, etc., is used for the heat roller at the time of fixing for a resin composition in which a high molecular weight component and a low molecular weight component are blended or copolymerized. It is added for the purpose of improving the mold releasability and improving the offset resistance. However, it is difficult for these release agents to improve the dispersibility in the binder resin, reverse polarity toner due to poor dispersion is likely to occur, and fogging to non-image areas occurs. In addition, an image defect such as a brush scraped off at the rear end portion of the solid black image portion occurs, and the image quality is deteriorated. There is also a problem of filming contamination of the carrier, the photoconductor, and the developing sleeve.
[0019]
In addition, when using a conventional toner having a low melting point releasing agent such as polypropylene or polyethylene and a low softening resin to improve the glossiness and translucency of a color image, the toner on the developing roller during development is used. If the dispersibility is improved due to the occurrence of vertical flaws, poor cleaning or filming of the intermediate transfer member, and scraping failure of the cleaning roller of the intermediate transfer member, the effect of releasability is reduced and the non-offset region Becomes narrow and difficult to achieve.
[0020]
Further, in the contact type one-component development system comprising an elastic blade that regulates the toner layer on a developing roller such as silicon resin or urethane resin, and a supply roller such as urethane resin that supplies toner to the developing roller, In a toner to which a low melting point release agent is added, the rising property of charge is deteriorated, and the charge maintenance property is deteriorated during long-term continuous use. Further, the use of the toner added with the low melting point releasing agent described above gradually causes vertical stripes on the developing roller when thousands of sheets are used, which causes image defects such as white spots and black stripes. This is thought to be due to the occurrence of scratches on the developing roller due to poor dispersion of the release agent, fusion to the blade, and aggregation due to friction between the supply roller and the developing roller.
[0021]
In addition, as described above, in recent years, from the viewpoint of protecting the global environment, it is preferable that waste toner remaining on the photoreceptor after transfer and collected by the cleaning unit is recycled again in the development step. However, when the waste toner is recycled, the toner appears damaged due to stress received in the transport pipe when the waste toner is returned to the cleaner section, the developing section, and the waste toner to the developing section.
[0022]
In addition, when the waste toner scraped off from the photosensitive member in the cleaning process is recycled again by development, if the release agent is poorly dispersed, particularly the particles whose dispersion has been reduced tend to become waste toner. When the new toner is mixed, the charge amount distribution becomes non-uniform, the reverse polarity toner increases, and the quality of the copy image is lowered. Further, in the toner added with a low melting point release agent, filming on the photosensitive member is promoted, which causes a reduction in life. In addition, a short paper such as a postcard is conveyed by a frictional force with the photosensitive drum. However, in a photosensitive member in which filming has occurred, the conveying force is reduced and a postcard passing paper becomes defective.
[0023]
In the transfer method using the conductive elastic roller, a transfer paper is inserted between the image bearing member and the conductive elastic roller, and a transfer bias voltage is applied to the conductive elastic roller to thereby transfer the image. The toner on the surface of the body is transferred to the transfer paper. However, the transfer method using the conductive elastic roller has a problem that the transfer paper is stained. This is because when the toner on the image carrier is transferred to transfer paper using a transfer roller, the transfer roller is in contact with the image carrier at a predetermined pressure in the absence of the transfer paper, and there is a lot of fog in the development process. This is because the transfer roller is contaminated by the fog, and the transfer roller contaminated by the toner comes into contact with the back surface of the transfer paper sent. In addition, in a toner whose release agent is poorly dispersed, fluidity is lowered, toner aggregation is partially increased, and voids are likely to occur during transfer. This is more noticeable when recycling waste toner.
[0024]
In addition, the intermediate transfer method does not require a complicated optical system, can also be used for stiff paper such as postcards and cardboard, and is flexible when an intermediate transfer belt is used, so it can be used as a transfer drum method or continuous transfer method. In comparison, there is an advantage that the device itself can be miniaturized. The toner is ideally transferred at the time of transfer, but a part of the transfer remains. The so-called transfer efficiency is not 100% and is generally about 75 to 90%. The toner remaining after transfer is scraped off by a cleaning blade or the like in the process of cleaning the photoconductor to become waste toner.
[0025]
In the configuration using the intermediate transfer member, the toner undergoes at least two transfer processes from the photosensitive member to the intermediate transfer member, and further from the intermediate transfer member to the image receiving paper. Then, for example, even if there is a transfer efficiency of 85%, the transfer efficiency is reduced to 72% by two transfers. Furthermore, the transfer efficiency of 75% with one transfer is 56%, and about half of the toner becomes waste toner, which increases the cost of the toner and increases the volume of the waste toner box. Then the size of the device cannot be reduced. The decrease in transfer efficiency is thought to be caused by reverse polarity ground cover or transfer omission due to poor dispersion of the release agent.
[0026]
In the case of color development, four color toner images are superimposed on the intermediate transfer member, so that the toner layer becomes thick and a pressure difference between the toner layer and the thin layer is likely to occur. For this reason, due to the toner aggregating effect, a part of the image is not transferred and a “collapse” phenomenon that becomes a hole is likely to occur. Further, if a material having a high toner release effect is used for the intermediate transfer member in order to ensure the cleaning when the image receiving paper is jammed, the voids appear remarkably and the quality of the image is remarkably deteriorated. Furthermore, edge development is performed on characters, lines, and the like, so that more toner is added, toners are agglomerated by pressurization, and voids become more prominent. In particular, it appears more conspicuously in a high humidity and high temperature environment.
[0027]
Further, it is necessary to clean and remove toner remaining without being transferred to the transfer material during the secondary transfer, and a rubber blade, a roller to which a bias is applied, a fur brush, or the like is used. At this time, the toner added with the low melting point release agent causes filming on the intermediate transfer member. Further, when the toner removed by the cleaning roller is scraped from the roller by the metal plate, the toner is fused to the metal plate, resulting in a scraping defect. In particular, filming and scraping defects are more likely to occur by using a low-melting sharp melt resin in order to express the glossiness and high translucency of a color image.
[0028]
In addition, an electrophotographic apparatus described later has an image forming unit group in which a plurality of movable image forming units that form toner images of different colors are arranged in an annular shape, and the entire image forming unit rotates. It is. In addition, the image forming unit and the intermediate transfer unit can be exchanged for each unit. When the end of the service life is reached, the unit can be easily replaced for maintenance. Can be obtained. However, since the image forming unit itself revolves, the cleaned waste toner repeatedly leaves and adheres to the photoconductor, which easily causes damage and filming to the photoconductor. Further, since the toner is repeatedly detached from and attached to the developing roller, the initial fog increases if the toner charge rising property is poor at the initial stage of development.
[0029]
In addition, it is important to realize a cleanerless process without a cleaning process because of the miniaturization of equipment and resource saving. After toner that has been visualized from the electrostatic latent image formed on the photosensitive member is transferred to a transfer material by a transfer unit, the toner remaining on the photosensitive member is usually recovered by cleaning and becomes waste toner. At this time, the cleaner-less process performs the following charging, exposure, and development processes without having a cleaning process step. First, it is indispensable to achieve high transferability in transfer, and toner spheroidization and transferability improvement using polymerized toner are being carried out. However, it is difficult for the remaining toner of 100% transfer to be zero, and it remains on the photoconductor to some extent. In the next development process, if the residual toner in the non-image area is returned to development, no image problems will occur. Therefore, the recovery of the toner remaining in the non-image area by development is an important point. In particular, toner with a low-melting-point release agent to satisfy non-offset properties at the time of fixing tends to decrease fluidity, and transferability is poor, and cleaner-less processes are difficult to recover in development. Therefore, the memory of the previous image pattern remains in the non-image portion.
[0030]
As described above, the toner must satisfy the above-described problems comprehensively. In particular, in an oilless fixing toner that does not use oil, the toner itself has the oil function used for the fixing member. Therefore, if a release agent such as wax is used in the toner, charging problems may occur, the charge amount cannot be increased, or the charge amount decreases during continuous use, and the toner itself does not have a lifetime, and development Problems such as toner fusing on the blade and filming on the photosensitive member occur, and it is very difficult to achieve both the fixability, developability and durability of the oilless toner.
[0031]
In view of the above problems, an object of the present invention is to provide a toner and an electrophotographic apparatus having a uniform charge distribution and capable of stabilizing an image for a long period of time.
[0032]
Even when used in the one-component development method, vertical streaks do not occur on the developing roller, and even when used continuously, the layer regulation blade and the developing roller do not cause thermal fusing or aggregation of toner, suppressing a decrease in charge amount, and resin An object of the present invention is to provide a toner and an electrophotographic apparatus capable of improving the dispersibility of the additive without deteriorating the characteristics and maintaining stable developability.
[0033]
In addition, the electrophotographic method using a conductive elastic roller and an intermediate transfer member can prevent hollowing out and scattering during transfer, achieve high transfer efficiency, avoid filming to the intermediate transfer member, etc., and a cleaning roller It is an object of the present invention to provide a toner and an electrophotographic apparatus that can prevent fusion to the toner.
[0034]
High transfer efficiency is obtained even in the cleanerless process, there is no decrease in charge amount and fluidity, no memory is generated during development, the cleanerless process is possible, and global environmental pollution prevention and resource reuse are possible. An object is to provide a toner and an electrophotographic apparatus.
[0035]
It is another object of the present invention to provide a full-color electrophotographic toner and an electrophotographic apparatus that exhibit high translucency and gloss by oilless fixing without oil application. In color toners that use low-melting sharp melt resins, filming on developing rollers, doctor blades, and intermediate transfer members can be avoided, and even for long-term use under high humidity, photoconductors and intermediate transfer An object of the present invention is to provide a toner and an electrophotographic apparatus that can prevent filming of the body.
[0036]
Also, in the fixing process using a belt, even in the belt fixing using a roller having a large curvature with a low fixing pressure and a long fixing nip, the non-wrapping property of the paper to the belt is good, but the curvature is large. Accordingly, it is an object of the present invention to provide a toner and an electrophotographic apparatus that can prevent chipping at the leading edge of the image that occurs when the belt and paper are separated, and that can achieve both development and transferability.
[0037]
[Means for Solving the Problems]
  In view of the above problems, the toner according to the present invention has at leastWith respect to 100 parts by weight of the binder resin and the binder resin,It is obtained by a reaction with a long-chain alkyl alcohol having 5 to 100 carbon atoms, an unsaturated polyvalent carboxylic acid or anhydride thereof, and a hydrocarbon wax, and has a weight average molecular weight of 1000 in the molecular weight distribution in gel permeation chromatography (GPC). ˜6000, Z average molecular weight is 1500 to 9000, the ratio of weight average molecular weight to number average molecular weight (weight average molecular weight / number average molecular weight) is 1.1 to 3.8, the ratio of Z average molecular weight to number average molecular weight (Z average (Molecular weight / number average molecular weight) is 1.5 to 6.5, molecular weight 1 × 10^Three~ 3x10^FourHaving at least one molecular weight maximum peak in the region, an acid value of 5 to 80 mg KOH / g, a melting point of 90 to 120 ° C., and a penetration at 25 ° C. of 4 or less.1 to 12 parts by weight of a fixing aid and 100 parts by weight of the binder resin,Of salicylic acid derivativesA toner base containing 0.5 to 5 parts by weight of a metal salt and 100 to 5 parts by weight of the binder resin, and 0.5 to 5 parts by weight of a metal salt of a benzylic acid derivative; The silica having the above was externally added to the toner base.Toner.
[0040]
  The toner according to the present invention has a weight average molecular weight of 10,000 to 200,000, a Z average molecular weight of 20,000 to 500,000, and a ratio of the weight average molecular weight to the number average molecular weight (weight average). The molecular weight / number average molecular weight) is 3 to 100, and the ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is 10 to 2000.^Three~ 3x10^Four3 × 10 as a component having at least one molecular weight maximum peak in the region and existing in the high molecular weight region^FourA polyester resin having 5% or more of the above molecular weight components with respect to the whole binder resin and an acid value of 1 to 40 mgKOH / g;For 100 parts by weight of the polyester resin,It is obtained by a reaction with a long-chain alkyl alcohol having at least 5 to 100 carbon atoms, an unsaturated polyvalent carboxylic acid or an anhydride thereof, and a hydrocarbon wax, and has a weight average molecular weight in a molecular weight distribution in gel permeation chromatography (GPC). 1000 to 6000, Z average molecular weight is 1500 to 9000, the ratio of weight average molecular weight to number average molecular weight (weight average molecular weight / number average molecular weight) is 1.1 to 3.8, ratio of Z average molecular weight to number average molecular weight (Z (Average molecular weight / number average molecular weight) is 1.5 to 6.5, molecular weight 1 × 10^Three~ 3x10^FourHaving at least one molecular weight maximum peak in the region, an acid value of 5 to 80 mg KOH / g, a melting point of 90 to 120 ° C., and a penetration at 25 ° C. of 4 or less.1 to 12 parts by weight of a fixing aid,0.5 to 5 parts by weight of a metal salt of a salicylic acid derivative with respect to 100 parts by weight of the polyester resin,A toner base containing 0.5 to 5 parts by weight of a metal salt of a benzylic acid derivative with respect to 100 parts by weight of the polyester resin and silica having a positive triboelectric charge property are externally added to the toner base. TheToner.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Digital image quality improvement, high color reproducibility colorization, high translucency and offset resistance can be achieved without using offset prevention oil for the fixing roller, and roller scratches and blades in one development component The toner of the present embodiment can achieve both the occurrence of vertical stripes due to fusion, the prevention of cleaning of the intermediate transfer member, and the scraping of the cleaning roller.
[0046]
In the past, in order to improve color fixability, a sharp melt low softening binder resin with a small molecular weight distribution and a small molecular weight distribution has been used. With this configuration, the translucency can be ensured, but since an offset occurs, it is necessary to apply oil to the fixing roller. In addition, in order to achieve oil-less fixing, the composition in which a release agent is added to a sharp-melt, low-softening binder resin makes it difficult to disperse the release agent, pigment, charge control agent, etc., and fog and poor charging. This causes inconveniences such as deterioration in transferability, deterioration in cleaning performance, filming on the photoconductor and developing roller, deterioration in rising of charging, and reduction in image density due to a decrease in charge amount during repeated use. The conventional polyolefin wax having releasability is difficult to disperse in the polyester resin, the chargeability is lowered and the image quality such as fog is lowered, and the color toner is turbid. Cannot get translucency.
[0047]
The toner of this embodiment makes it possible to achieve both of these various electrophotographic characteristics.
[0048]
With the toner of this embodiment, fixing characteristics, particularly non-offset property, high glossiness, and high translucency in oilless fixing can be exhibited by adding a fixing aid, and high temperature storage stability is not deteriorated. Further, even if a fluorine-based or silicon-based member is used for the fixing roller, halftone offset can be prevented. Furthermore, charging stability during continuous use can be obtained, and both fixing ability and development charging stability can be achieved.
[0049]
Furthermore, by improving the dispersion state when this is added to the binder resin, it is possible to further improve the releasability, fixability such as translucency, and developability such as charge stabilization. Although it is conceivable that the dispersibility of other internal additives is lowered by the addition of a release agent, both the fixability and the developability are achieved without lowering the dispersibility of both by the configuration of the additive of this embodiment. be able to.
[0050]
When the carbon number of the long-chain alkyl is smaller than 5, the releasing action is weakened and the fixing offset property is lowered. In addition, the dispersibility with the charge control agent becomes poor, leading to filming, fusion, and a decrease in chargeability during continuous use. When the carbon number of the long-chain alkyl is larger than 100, the dispersibility of the fixing aid itself is deteriorated in the binder resin. If the acid value is less than 5 mgKOH / g, the charge amount during long-term use of the toner is reduced. When the acid value is greater than 80 mgKOH / g, the moisture resistance decreases, and the fogging under high humidity increases. When the melting point is lower than 90 ° C., the storage stability of the toner is lowered. When the melting point is higher than 120 ° C., the releasing action is weakened and the non-offset temperature range is narrowed. When the penetration at 25 ° C. is larger than 4, the toughness is lowered, and filming occurs on the photosensitive member and the intermediate transfer member during long-term use.
[0051]
Weight average molecular weight smaller than 1000, Z average molecular weight smaller than 1500, Weight average molecular weight / number average molecular weight smaller than 1.1, Z average molecular weight / number average molecular weight smaller than 1.5, molecular weight maximum peak Is 1 × 10^ThreeIf it is located in a smaller range, the dispersibility of the charge control agent as well as the fixing aid deteriorates. The storage stability of the toner is deteriorated, filming of the photosensitive member and the intermediate transfer member, vertical stripes on the developing roller, and scraping failure on the cleaning roller may occur.
[0052]
The weight average molecular weight is greater than 6000, the Z average molecular weight is greater than 9000, the weight average molecular weight / number average molecular weight is greater than 3.8, the Z average molecular weight / number average molecular weight is greater than 6.5, and the molecular weight maximum The peak is 3 × 10^FourIf it is located in a range larger than this area, the releasing action is weakened and the fixing offset property is lowered.
[0053]
More preferably, the weight average molecular weight is 1000 to 5000, the Z average molecular weight is 1700 to 8000, the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.2 to 2.8, and the Z average molecular weight is Number-average molecular weight ratio (Z-average molecular weight / number-average molecular weight) is 1.5 to 4.5, 1 × 10^Three~ 1x10^FourIt is preferable to have at least one molecular weight maximum peak in the region, more preferably, the weight average molecular weight is 1000 to 2500, the Z average molecular weight is 1900 to 3000, and the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average). Molecular weight) is 1.2 to 1.8, and the ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is 1.7 to 2.5, 1 × 10.^Three~ 3x10^ThreeIt has at least one molecular weight maximum peak in the region.
[0054]
As the alcohol, those having a long alkyl chain such as octanol, dodecanol, stearyl alcohol, nonacosanol, pentadecanol and the like can be used. Moreover, N-methylhexylamine, nonylamine, stearylamine, nonadecylamine, etc. can be used conveniently as amines. As the fluoroalkyl alcohol, 1-methoxy- (perfluoro-2-methyl-1-propene), hexafluoroacetone, 3-perfluorooctyl-1,2-epoxypropane and the like can be preferably used. As the unsaturated polyvalent carboxylic acid or anhydride thereof, one or more of maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and the like can be used. Of these, maleic acid and maleic anhydride are more preferable. As the synthetic hydrocarbon wax, polyethylene, polypropylene, Fischer-Tropsch wax, α-olefin and the like can be suitably used.
[0055]
Unsaturated polyhydric carboxylic acid or its anhydride is polymerized with alcohol or amine, and this is then added to synthetic hydrocarbon wax in the presence of dicrummi peroxide or tertiary butyl peroxyisopropyl monocarbonate. Can be obtained.
[0056]
The addition amount is preferably 1 to 12 parts by weight with respect to 100 parts by weight of the binder resin. If it is less than 1 part by weight, the mold release effect is difficult to appear. When the amount is more than 12 parts by weight, not only the fluidity of the toner is lowered, but even if added more, the effect is not improved by saturation.
[0057]
  In this embodiment, in order to make the toner charge control purpose and oilless fixing stronger, the above-mentioned fixing aid and charge control agent are combined in the binder resin. Preferred materialsMetal salts of benzylic acid derivatives shown in (Chemical formula 5)Is used.
[0058]
[Chemical formula 5]

  (R¹, R^FourRepresents a hydrogen atom, an alkyl group or an aromatic ring which may have a substituent, and R², R^ThreeRepresents an aromatic ring which may be substituted. X represents an alkali metal)
[0059]
  In this embodiment, in order to further strengthen the purpose of charge control of the toner and oilless fixing, the above-mentioned fixing aid and charge control agent are combined in the binder resin. Preferred materialsMetal salt of salicylic acid derivative shown in (Chemical formula 6)Is used.
[0060]
[Chemical 6]

[0061]
With this configuration, a wide non-offset temperature range can be secured in oil-less fixing, and image disturbance due to charging during fixing can be prevented. This seems to be the effect of the charging polarity of the functional group having the acid value of the fixing assistant and the metal salt. In addition, it is possible to prevent a decrease in charge amount during continuous use. Blade fusion during development can be suppressed.
[0062]
The addition amount is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the binder resin. More preferably, it is 1-4 weight part, More preferably, it is 3-4 weight part. When the amount is less than 0.5 parts by weight, the charging effect is lost. If it is larger than 5 parts by weight, the color turbidity in the color image becomes conspicuous.
[0063]
In the toner of the present embodiment, a polyester resin is used as the binder resin, the fixing aid is used in combination with the fixing aid and the charge control agent, and the molecular weight of the toner or the polyester resin is specified. Thus, the dispersion of the charge control agent can be made better, and the chargeability can be stabilized. In addition, toner aggregation can be prevented, and filming on the photosensitive member, the intermediate transfer member, and the developing roller can be prevented even when used continuously for a long period of time. We have created a configuration that can ensure high translucency and high color reproducibility in fixing, and can expand the offset width to a higher temperature range without requiring fixing oil. In development, a higher stress is applied to increase the chargeability, and in the cleaning of the intermediate transfer member, a higher load is applied to improve the cleaning performance. In addition, the development unit itself revolves, and even in a state where strong stress is applied to the toner, the durability, transferability, recyclability, and chargeability are improved while maintaining high light transmissivity, fixing ability and developability, It has been found that it is possible to achieve a better balance between durability. By having a sharp molecular weight distribution, we have created a configuration that can ensure high translucency and prevent offset without the need for fixing oil.
[0064]
Specifically, the molecular weight distribution in GPC as a binder resin is 2 × 10.^Three~ 3x10^Four3 × 10 as a component having at least one molecular weight maximum peak in the region and existing in the high molecular weight region^FourIt has 5% or more of the above molecular weight components with respect to the whole binder resin, the weight average molecular weight is 10,000 to 200,000, the Z average molecular weight is 20,000 to 500,000, and the ratio of the weight average molecular weight to the number average molecular weight (weight average The molecular weight / number average molecular weight) is 3 to 100, the ratio of the Z average molecular weight to the number average molecular weight (Z average molecular weight / number average molecular weight) is 10 to 2000, and the melting temperature by the 1/2 method using the Koka type flow tester (hereinafter softening) It is preferable to use as a component a polyester resin having a point) of 80 to 150 ° C., an outflow start temperature of 80 to 120 ° C., and a glass transition point of the resin of 45 to 68 ° C.
[0065]
Preferably, the weight average molecular weight is 10,000 to 120,000, the Z average molecular weight is 20,000 to 300,000, the weight average molecular weight / number average molecular weight is 3 to 50, the Z average molecular weight / number average molecular weight is 10 to 1,000, and the softening point is 90. It is preferable to use as a component a polyester resin having a temperature of ˜140 ° C., an outflow start temperature of 85 to 115 ° C., and a glass transition point of 52 to 65 ° C. More preferably, the weight average molecular weight is 10,000 to 40,000, the Z average molecular weight is 20,000 to 100,000, the weight average molecular weight / number average molecular weight is 3 to 20, the Z average molecular weight / number average molecular weight is 10 to 100, and the softening point is It is preferable to use as a component a polyester resin having a temperature of 105 to 135 ° C, an outflow start temperature of 90 to 120 ° C, and a glass transition point of 58 to 65 ° C.
[0066]
Moreover, as a component which exists in a high molecular weight area | region, Preferably it is 1x10.^FiveIt is preferable to have the above molecular weight components at 3% or more with respect to the entire binder resin. Furthermore, as a component existing in the high molecular weight region, 3 × 10^FiveIt is preferable to have 0.5% or more of the above molecular weight components with respect to the whole binder resin.
[0067]
Preferably 8 × 10 8 as a component present in the high molecular weight region^Four~ 1x10⁷Having a molecular weight component of 3% or more with respect to the entire binder resin, and 1 × 10⁷The structure which does not contain the above components is preferable.
[0068]
More preferably, as a component present in the high molecular weight region, 3 × 10^Five~ 9x10⁶Having a high molecular weight component of 1% or more with respect to the whole binder resin, and 9 × 10⁶The above components are not included.
[0069]
More preferably, as the component existing in the high molecular weight region, 7 × 10^Five~ 6 × 10⁶Having a high molecular weight component of 1% or more with respect to the whole binder resin, and 6 × 10⁶The above components are not included.
[0070]
If the amount of the high molecular weight component is too large or too large, the large molecular weight component remains at the time of kneading and hinders the translucency. In addition, the production efficiency of the resin itself decreases. Unnecessary scratches are made on the developing roller supply roller to cause vertical stripes in the image. Further, the dispersibility of the fixing aid is lowered.
[0071]
The binder resin has a weight average molecular weight of less than 10,000, a Z average molecular weight of less than 20,000, a weight average molecular weight / number average molecular weight of less than 3, a Z average molecular weight / number average molecular weight of less than 10, and a softening point of 80. When the temperature is lower than 0 ° C., the outflow start temperature is lower than 80 ° C., and the glass transition point is lower than 45 ° C., the dispersibility at the time of kneading decreases, resulting in an increase in fog and a deterioration in durability. Further, the kneading stress during kneading is not sufficiently applied, and the molecular weight cannot be maintained at an appropriate value. The dispersibility of the fixing aid is reduced, offset resistance and high-temperature storage stability are deteriorated, and further, cleaning failure on the intermediate transfer member and filming on the photosensitive member occur.
[0072]
The weight average molecular weight of the binder resin is greater than 200,000, the Z average molecular weight is greater than 500,000, the weight average molecular weight / number average molecular weight is greater than 100, the Z average molecular weight / number average molecular weight is greater than 2000, and the softening point is 150. If it is greater than ℃, the outflow start temperature is greater than 120 ℃, and the glass transition point is greater than 68 ℃, the load during processing of the machine becomes excessive, resulting in an extreme decrease in productivity and a decrease in translucency in color images. And lead to a decrease in fixing strength.
[0073]
Furthermore, the molecular weight distribution in GPC of the melt-kneaded toner is 2 × 10^Three~ 3x10^FourHaving at least one molecular weight maximum peak in the region of 5 × 10^Four~ 1x10⁶It is set as the structure which has at least 1 molecular weight maximum peak or shoulder in this area | region. Preferably, the maximum molecular weight peak present on the low molecular weight side of the toner is 3 × 10^Three~ 2x10^FourAt least one in the region, more preferably 4 × 10^Three~ 2x10^FourIt is the structure which has at least one in the area | region.
[0074]
The position of the maximum molecular weight peak or shoulder existing on the high molecular weight side of the toner is 6 × 10.^Four~ 7 × 10^FiveAt least one in the region, more preferably 8 × 10^Four~ 5x10^FiveThis region has at least one molecular weight maximum peak or shoulder.
[0075]
The molecular weight maximum peak position of the molecular weight distribution of the toner present on the low molecular weight side is 2 × 10^ThreeWhen it becomes smaller, the durability deteriorates and 3 × 10^FourWhen it is larger, the fixing property is deteriorated, and the translucency is lowered.
[0076]
Further, the position of the molecular weight maximum peak or shoulder of the molecular weight distribution of the toner existing on the high molecular weight side is 5 × 10 5.^FourWhen it becomes smaller, the offset resistance is lowered, and the storage stability is deteriorated. Deterioration of developability and waste toner recyclability are also reduced. 1 × 10⁶When it is larger, the grindability is lowered and the production efficiency is lowered.
[0077]
Further, as a component present in the high molecular weight region of the toner, 5 × 10^FiveThe content of the high molecular weight component is preferably 10 wt% or less with respect to the entire binder resin. 5 × 10^FiveThe components present in the above high molecular weight region increase or the enormous state is a result of the kneading state becoming defective because the uniform kneading stress is not applied to the toner constituting material during kneading. Thereby, translucency is remarkably inhibited. Further, an increase in fog due to poor dispersion, generation of scratches on the developing roller and the supply roller, deterioration of toner pulverization, and manufacturing efficiency are lowered.
[0078]
More preferably, 5 × 10^FiveThe content of the high molecular weight component is 5% or less with respect to the whole binder resin, more preferably 1 × 10.⁶The content of the above high molecular weight components is 1% or less with respect to the whole binder resin, or it does not contain.
[0079]
The molecular weight distribution in the GPC chromatogram of the toner is 2 × 10.^Three~ 3x10^FourThe height of the molecular weight distribution of the molecular weight maximum peak existing in the region of Ha is 5 × 10^Four~ 1x10⁶Hb / Ha is 0.15 to 0.9, where Hb is the maximum molecular weight peak or shoulder height existing in the region.
[0080]
When Hb / Ha is smaller than 0.15, the offset resistance is deteriorated, the storage stability is also lowered, and the filming on the developing sleeve and the photosensitive member is promoted. If it exceeds 0.9, the developing roller supply roller will be damaged, the grindability will deteriorate, the productivity will decrease, and the cost will increase. More preferably, Hb / Ha is 0.15 to 0.7, and still more preferably Hb / Ha is 0.2 to 0.6.
[0081]
Further, in order to prevent offset even if high translucency can be ensured and no fixing oil is required, the molecular weight distribution in the GPC of the toner is 2 × 10.^Three~ 3x10^FourAt least one molecular weight maximum peak in the region of 5 × 10^Four~ 1x10⁶And having a molecular weight maximum of 5 × 10^Four~ 1x10⁶Paying attention to the molecular weight curve in the region larger than the molecular weight value corresponding to the maximum peak or shoulder corresponding to the molecular weight distribution existing in the region, the molecular maximum peak based on the maximum peak or shoulder height of the molecular weight distribution as 1 Alternatively, when the molecular weight corresponding to 90% of the height of the shoulder is M90 and the molecular weight corresponding to the molecular weight maximum peak or the height of 10% of the shoulder is M10, M10 / M90 is 0.00. It is realizable by setting it as 5-8. Furthermore, it can be realized by setting (M10-M90) / M90 to 0.1-7.
[0082]
Defining the value of M10 / M90, and further (M10-M90) / M90 (the slope of the molecular weight distribution curve) can quantify the state of molecular cleavage of the ultrahigh molecular weight component, and this value is If it is within the stated range (implying that the slope of the molecular weight distribution curve is steep), the ultra-high molecular weight component that impedes the light transmission is lost by cutting during kneading, resulting in high light transmission. To have. Furthermore, the high molecular weight component forming the peak or shoulder appearing on the polymer side contributes to offset resistance, and it is possible to prevent the occurrence of color toner offset without using oil.
[0083]
Furthermore, when this ultra-high molecular weight component is molecularly cleaved, it is possible to uniformly disperse the fixing aid and charge control agent in the binder resin, and the charge amount is made uniform and clear resolution is achieved. And even if it is used continuously for a long time, the durability is not deteriorated. Further, the cleaning property of the intermediate transfer member is improved, vertical stripes are not generated on the developing roller, and the void during transfer can be prevented and high-efficiency transfer property can be obtained.
[0084]
When the value of M10 / M90 is larger than 8 or (M10−M90) / M90 is larger than 7, the ultra-high molecular weight component still remains and inhibits translucency. When the value of M10 / M90 is smaller than 0.5 or (M10−M90) / M90 is smaller than 0.1, the mechanical load during kneading becomes excessive and productivity is lowered. The durability of the toner is reduced. More preferably, the value of M10 / M90 is 0.5 to 6, and (M10−M90) / M90 is 0.1 to 4.5. More preferably, the value of M10 / M90 is 0.5 to 4.5, and (M10-M90) / M90 is 0.1 to 3.5.
[0085]
As a result, digital high image quality, high color reproducibility colorization, contact type one-component development, the development roller and supply roller can be used stably for a long time, and the fixing roller does not use oil for preventing offset. Both the translucency and the offset resistance can be achieved, and further, a cleaner process can be realized, and a high transfer property in a transfer process using an intermediate transfer member can be realized.
[0086]
By kneading the above-described binder resin with a high shearing force in the melt-kneading process, it is possible to develop characteristics that are not conventionally obtained. Fixing without using oil makes it possible to achieve both high translucency and offset resistance of color toners. In other words, the binder resin to which the ultra-high molecular weight component has been added has a high shearing force, the ultra-high molecular weight component is lowered to a high molecular weight, thereby exhibiting high translucency. The offset property is also satisfactory. In addition, since it has an ultra-high molecular weight component, high shearing force is applied during kneading, making it possible to disperse the fixing aid more uniformly, improving translucency, non-offset properties, high image quality, and high color reproduction. Sex is obtained.
[0087]
The weight average molecular weight of the toner after the melt-kneading treatment is 8000 to 180,000, the Z average molecular weight is 18,000 to 450,000, the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 3 to 80, Z average The ratio between the molecular weight and the number average molecular weight (Z average molecular weight / number average molecular weight) is 10 to 1000.
[0088]
By kneading the toner with a high shearing force within this suitable range, it is possible to achieve both high translucency and offset resistance of the color toner by fixing without using oil.
[0089]
Preferably, the weight average molecular weight is 8000 to 100,000, the Z average molecular weight is 18000 to 300,000, the weight average molecular weight / number average molecular weight is 3 to 60, and the Z average molecular weight / number average molecular weight is 10 to 500.
[0090]
More preferably, the weight average molecular weight is 10,000 to 40,000, the Z average molecular weight is 20,000 to 80,000, the weight average molecular weight / number average molecular weight is 3 to 30, and the Z average molecular weight / number average molecular weight is 10 to 50. preferable.
[0091]
When the weight average molecular weight is less than 8000, the Z average molecular weight is less than 18000, the weight average molecular weight / number average molecular weight is less than 3, and the Z average molecular weight / number average molecular weight is less than 10, kneading stress is not sufficiently applied, The molecular weight cannot be maintained at an appropriate value. The dispersibility of the fixing aid is reduced, offset resistance and high-temperature storage stability are deteriorated, and further, cleaning failure on the intermediate transfer member and filming on the photosensitive member occur.
[0092]
If the weight average molecular weight is greater than 180,000, the Z average molecular weight is greater than 450,000, the weight average molecular weight / number average molecular weight is greater than 80, and the Z average molecular weight / number average molecular weight is greater than 1000, the pressure of the shearing force is too high. On the contrary, internal additives such as charge control agents cause aggregation to each other, leading to a decrease in dispersibility, leading to an increase in fog during the cleaner process, a decrease in image density, and a transfer failure. In addition, the fixing strength is reduced, and the translucency and glossiness are reduced.
[0093]
The binder resin has a THF insoluble component of 5% by weight or less, and preferably has no THF insoluble component. If the THF-insoluble component is more than 5% by weight, the translucency of the color image is deteriorated and the image quality is deteriorated.
[0094]
As the binder resin suitably used in this embodiment, a polyester resin obtained by polycondensation of an alcohol component and a carboxylic acid component such as a carboxylic acid, a carboxylic acid ester, or a carboxylic anhydride is preferably used.
[0095]
Examples of divalent carboxylic acids or lower alkyl esters include malonic acid, succinic acid, glutaric acid, adipic acid, hexahydrophthalic anhydride and other aliphatic dibasic acids, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid And aliphatic unsaturated dibasic acids such as phthalic anhydride, phthalic anhydride, terephthalic acid and isophthalic acid, and methyl and ethyl esters thereof. Of these, aromatic dibasic acids such as succinic acid, phthalic acid, terephthalic acid, and isophthalic acid, and lower alkyl esters thereof are preferred. The use of succinic acid and terephthalic acid or a combination of phthalic acid and terephthalic acid is preferred.
[0096]
Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, , 2,4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexatricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarbopropane, tetra (methylenecarboxyl) Examples include methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, emporic trimer acid, acid anhydrides thereof, and alkyl (carbon number 1 to 12) esters.
[0097]
Examples of the dihydric alcohol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, Examples include diols such as dipropylene glycol, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct, triols such as glycerin, trimethylolpropane, and trimethylolethane, and mixtures thereof. Among these, neopentyl glycol, totimethylolpropane, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct are preferable.
[0098]
Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1 , 2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. It is done.
[0099]
For the polymerization, known polycondensation, solution polycondensation or the like can be used. As a result, a good toner can be obtained without impairing the PVC mat resistance and the color of the color toner.
[0100]
The ratio of the polyvalent carboxylic acid and the polyhydric alcohol is generally 0.8 to 1.4 in terms of the ratio of the number of hydroxyl groups to the number of carboxyl groups (OH / COOH).
[0101]
The molecular weight of the resin and the toner is a value measured by gel permeation chromatography (GPC) using several types of monodisperse polystyrene as a standard sample.
[0102]
The apparatus is HPLC 8120 series manufactured by Tosoh Corporation, the column is TSKgel superHM-H H4000 / H3000 / H2000 (7.8 mm diameter, 150 mm × 3), eluent THF (tetrahydrofuran), flow rate 0.6 ml / min, sample concentration 0.1 %, Injection amount 20 μL, detector RI, measurement temperature 40 ° C., pretreatment for measurement is to measure a resin component obtained by dissolving a sample in THF and filtering through a 0.45 μm filter to remove additives such as silica. The measurement conditions are conditions in which the molecular weight distribution of the target sample is included in a range in which the logarithm of the molecular weight and the count number are linear in a calibration curve obtained with several types of monodisperse polystyrene standard samples.
[0103]
The fixing aid is a value measured by GPC using several types of monodisperse polystyrene as a standard sample, but unlike the resin and toner described above, the apparatus is a GPC-150C manufactured by WATERS, the column is a Shodex HT-806M ( 8.0 mm ID-30 cm × 2), the eluent is o-dichlorobenzene, the flow rate is 1.0 mL / min, the sample concentration is 0.3%, the injection volume is 200 μL, the detector is RI, and the measurement temperature is 130. In the pre-measurement treatment at 0 ° C., the sample was dissolved in a solvent and filtered through a 0.5 μm sintered metal filter. The measurement conditions are conditions in which the molecular weight distribution of the target sample is included in a range in which the logarithm of the molecular weight and the count number are linear in a calibration curve obtained with several types of monodisperse polystyrene standard samples.
[0104]
The softening point of the binder resin is 1 cm by a flow tester (CFT500) manufactured by Shimadzu Corporation.^ThreeThe sample was heated at a rate of temperature increase of 6 ° C./min.^FiveN / m²The temperature at which the piston stroke starts to rise is the outflow start temperature (Tfb) from the relationship between the temperature rise characteristic in the relationship between the piston stroke and the temperature of the plunger. ), 1/2 of the difference between the lowest value of the curve and the end point of the outflow is obtained, and the temperature at the point of adding the lowest value of the curve is the melting temperature (softening point Tm) in the 1/2 method.
[0105]
The glass transition point of the resin was raised to 100 ° C. using a differential scanning calorimeter, left at that temperature for 3 minutes, and then cooled to room temperature at a cooling rate of 10 K / min. When the thermal history is measured by raising the temperature, the temperature at the intersection of the base line extension below the glass transition point and the tangent that indicates the maximum slope from the peak rising portion to the peak apex is said.
[0106]
For the melting point of the endothermic peak by DSC, a differential calorimeter DSC-50 manufactured by Shimadzu Corporation was used. The temperature was raised to 200 ° C. at 5 K / min, rapidly cooled to 10 ° C. for 5 minutes, allowed to stand for 15 minutes, then heated at 5 K / min, and obtained from the endothermic (melting) peak. The amount of sample put into the cell was 10 mg ± 2 mg.
[0107]
By kneading with a high shear force, characteristics such as fixability and development durability are improved.
[0108]
Specifically, it has two opposing rolls that rotate in different directions and can be heated or cooled, and the temperature difference between the roll temperature of one roll (RL1) and the roll temperature of the other roll (RL2). The roll (RL1) and the roll (RL2) are rotated at different peripheral speeds and kneaded between the two rolls. Furthermore, one of the rolls (RL1) has a temperature difference between the first half and the second half.
[0109]
Then, the temperature setting and temperature gradient of the roll, the kneading conditions of the rotation speed and the load current, the softening point of the binder resin, the melting point of the fixing aid, and the addition amount are improved by processing under optimum conditions.
[0110]
By carrying out the rotation speed ratio of the two rolls within the range of 1.1 to 2.5 times, an appropriate shearing force is generated during kneading, and the dispersibility of the internal additives such as the molecular cutting of the binder resin and the colorant. And the fixability and developability are improved. In this configuration, the rotation ratio of the roll on the side of heating and melting and winding the toner is increased. When it is 1.1 times or less, an appropriate shearing force is not generated, dispersibility is not improved, and translucency is deteriorated. On the other hand, if it is 2.5 times or more, productivity is drastically reduced, dispersibility is not improved, and developability is deteriorated.
[0111]
Further, by kneading under such conditions that the ratio of the load current values applied to the two rolls is in the range of 1.25 to 10, an appropriate shearing force is applied and the dispersibility of the internal additive is improved. . If it is smaller than this range, the dispersibility is not improved, and the translucency is deteriorated. Productivity also decreases. On the other hand, if it is larger than this range, the load applied to the roller becomes too large, and the ultra-high molecular weight component becomes too low in molecular weight, so that the non-offset property is lowered and offset occurs.
[0112]
When a fixing assistant having a temperature lower than the softening point of the binder resin is added, the more the amount of the fixing assistant is added, the higher the roll temperature is, the better the melt winding around the roll cannot be performed. Usually, it is considered that treatment with a lower temperature is possible by adding a low melting point, but the release action is strong and tends to be easily separated from the roller. Accordingly, it is necessary to perform the treatment at a high temperature. However, if the treatment is performed at a high temperature, the shearing force becomes weak and the dispersibility of the fixing aid is lowered. On the other hand, when the temperature is low, winding becomes poor, scattering and separation occur, and productivity is lowered. Therefore, at this time, the roll temperature of the first half is Trj1, the roll temperature of the second half is Trk1, the softening point of the binder resin (melting temperature in the 1/2 method) is Tm, the melting point of the fixing aid by the DSC method is Tw, and the fixing aid is When the additive amount of the agent is Sw (the blending amount (parts by weight) ratio with respect to 100 parts by weight of the binder resin), the melt wrapping around the roll can be performed satisfactorily by processing so as to satisfy the relationship of (Equation 5). At the same time, the dispersibility of the fixing aid can be appropriately achieved.
[0113]
[Equation 5]

[0114]
If the value of q is small, the winding will be poor and the dispersibility of the fixing aid will not be improved. When the value of q is increased, the shearing force action is not sufficiently applied, leading to a decrease in translucency, filming on the intermediate transfer member, and poor cleaning.
[0115]
Further, in one roll in which the toner is melted and wound, a temperature difference is provided between the first half (IN side) for supplying the raw material and the second half (OUT side) for taking out the kneaded material. On the IN side, the temperature is set high to melt and wrap the supplied material around the roller, and on the OUT side, the temperature is lowered to give shearing force to the material, improving the resin molecular cutting and fixing aid dispersibility. Let The difference in temperature of the material conveyed from the IN side to the OUT side means that the binder resin is melted to some extent on the IN side and the fixing aid is separated in the resin, which is a low temperature on the OUT side. Due to the stronger shearing force, the dispersibility can be made uniform. In addition, molecular cutting of the resin can be performed appropriately. At this time, the roll temperature on the IN side is Trj1, the roll temperature on the OUT side is Trk1, the softening point of the binder resin is Tm, and the addition amount of the fixing aid is Sw (the amount (parts by weight) relative to 100 parts by weight of the binder resin) ), By performing processing so as to satisfy the relationship of (Equation 6), it is possible to satisfactorily melt and wind the roll, and to appropriately disperse the fixing aid.
[0116]
[Formula 6]

[0117]
If the value of j is large, the shearing force on the OUT side is not sufficiently applied, and the dispersibility of the fixing aid is not improved. The translucency at the time of fixing decreases, causing vertical streaks on the developing roller, fogging, and poor cleaning on the intermediate transfer member. If the value of j is reduced, the floating state of the molten film from the roller occurs, and on the contrary, the shearing force action is not sufficiently applied, resulting in reduced translucency, filming on the intermediate transfer member, and poor cleaning. Trigger.
[0118]
By processing in the above state, high molecular weight molecular cutting at the time of kneading can be performed in an appropriate state, and internal additives, particularly pigments and charge control agents can be uniformly kneaded and dispersed. It is possible to realize both offset property and light resistance and fixing without using oil.
[0119]
Further, the uniformity of dispersion can be further improved, and high transferability and developability can be improved. Moreover, the characteristics under high temperature and high humidity and low temperature and low humidity can be stabilized.
[0120]
In the developing process of this embodiment, an elastic blade such as rubber or metal is brought into contact with an elastic or rigid developing roller with a constant pressure, and a thin layer of toner is formed and developed by contact or non-contact with the photoreceptor. It is the structure to do. As a one-component development method, a sponge-based supply roller made of urethane resin and a development roller made of silicon resin or urethane resin are brought into contact with each other with a certain amount of biting, and toner is supplied from the supply roller to the development roller, and then on the development roller. A thin layer of toner is formed by contacting an elastic rubber or metallic stainless doctor blade, or rotating a metallic roller against the developing roller against the developing roller (in the same direction), and contacting it with the photoreceptor. Alternatively, a developing method in which a toner image is formed by applying direct current or alternating current without contact is preferably used.
[0121]
At this time, the frequency of the AC bias is 0.5 to 10 kHz, the AC bias is 0.3 to 1.2 kV (pp), and the peripheral speed ratio between the photoconductor and the developing roller is 1: 1.2 to 1. : 1.8 makes it possible to reproduce the dots faithfully, achieve good development γ characteristics, and realize a high-quality image. As a result, low fog and high image density can be obtained. The frequency is 0.5 to 5 kHz, the AC bias is 0.3 to 1.0 kV (pp), and the peripheral speed ratio between the photosensitive member and the developing roller is 1: 1.2 to 1: 1.5. More preferably, the frequency is 0.5 to 2 kHz, the AC bias is 0.5 to 0.9 kV (pp), and the peripheral speed ratio between the photoreceptor and the developing roller is 1: 1.2 to 1: 1.4.
[0122]
At this time, if the frequency is smaller than 0.5 kHz, dot reproducibility deteriorates and halftone reproducibility deteriorates. When the frequency is higher than 10 kHz, the development region cannot be followed and the effect does not appear. When the AC bias is smaller than 0.3 kV (pp), the solid followability maintaining effect cannot be obtained, and when the AC bias is larger than 1.2 kV (pp), the fog increases. If the peripheral speed ratio between the photoconductor and the developing roller is smaller than 1: 1.2 (the developing roller becomes slow), it is difficult to obtain image density. When the peripheral speed ratio between the photosensitive member and the developing roller is larger than 1: 1.8 (the developing roller speed is increased), toner scattering increases.
[0123]
The supply roller and the development roller are rotated in the same direction, and the peripheral speed of the development roller and the supply roller is increased by 1: 1 to 0.8: 0.2. The developing roller is 9.8 × 10 on the surface of the photoreceptor.²~ 9.8 × 10^Four(N / m²) To develop the electrostatic latent image on the photosensitive member. The elastic blade is 5 × 10^Three~ 5x10^Five(N / m²The toner layer is formed on the developing roller by pressure.
[0124]
Further, a sponge-like supply roller made of urethane resin or the like is used as a developing roller in order to control the toner conveying amount on the developing roller when the amount of toner supplied from the toner reservoir is conveyed onto the developing roller. In contrast, a constant bite amount of 0.1 to 1 mm is used so as to contact the developing roller.
[0125]
A sponge-like supply roller made of urethane resin or the like is brought into contact with the developing roller in order to control the toner conveying amount on the developing roller when the amount of toner supplied from the toner reservoir is conveyed onto the developing roller to a constant amount. The structure which comprises is taken. This is an effective means for restricting the toner transport amount to a constant amount.
[0126]
However, in this configuration, when used for a long period of time, a defect on the developing roller and an image defect in which vertical stripes are generated on the image due to adhesion of foreign matter to the blade are likely to occur. In particular, in order to improve the color fixing property, this phenomenon occurs more remarkably in the use of a low softening binder resin or a toner to which a low melting point release agent is added.
[0127]
In addition, the amount of toner transported on the developing roller decreases during long-term continuous use, and solid follow-up defects in which the density in the latter half of the image is partially reduced when a solid black image is taken are likely to occur. When the charge amount of the toner on the developing roller was measured by a suction method, it was found that the charge amount was greatly reduced. Further pursuing, the charge amount of the toner in the supply roller portion is greatly increased, that is, the decrease in the image density is not the decrease in the charge amount of the toner, but in the supply roller portion before being supplied to the developing roller. This is because the charging capacity has been increased and the supply capability from the supply roller to the developing roller has been reduced. Therefore, it is necessary to have a configuration capable of ensuring image density while preventing toner scattering. Although it is effective to increase the charging force of the toner by increasing the pressure contact force of the doctor blade, the toner tends to be fused, and the developing roller is damaged.
[0128]
Accordingly, it has been found that the toner configuration of the present embodiment can prevent the occurrence of vertical stripes on the developing roller, poor solid followability, and toner fusion without sacrificing the fixing characteristics.
[0129]
This enables uniform dispersion in the resin, stabilizes the charge distribution, suppresses overcharging of the toner on the supply roller, stabilizes the image density during continuous use, and improves the solid followability. . Uniform dispersion can maintain the fluidity of the toner, and the toner can be smoothly transported on the developing roller, and the transport state can be constantly stabilized. In particular, the effect is great for stabilizing the conveyance state under high humidity. At this time, it is preferable that the charge amount of the toner on the developing roller by the suction type Faraday cage method is −5 to −45 μC / g. When it is −5 μC / g or less, toner scattering increases. When it is −45 μC / g or more, it is difficult to obtain an image density.
[0130]
Further, in this embodiment, a primary transfer process in which the toner image formed on the surface of the photoconductor is brought into contact with the surface of the endless intermediate transfer member on the surface of the photoconductor and the toner image is transferred to the surface is performed a plurality of times. After that, a secondary transfer process is performed in which the overlapping transfer toner image formed on the surface of the intermediate transfer member is transferred to a transfer material such as a copy sheet in a batch by repeating the primary transfer process a plurality of times. It is suitably used for an electrophotographic apparatus having a transfer system configured as described above. At this time, the photosensitive member and the intermediate transfer member are 9.8 × 10²~ 2x10^Five(N / m²The toner on the photoconductor is transferred by pressure contact. In addition, the toner image formed on the surface of the intermediate transfer member has a surface of the intermediate transfer member on the surface of the intermediate transfer member.^Three~ 2x10^Five(N / m²) The toner is transferred onto the recording material by pressing with pressure.
[0131]
At this time, it is necessary to clean and remove toner remaining without being transferred to the transfer material during the secondary transfer, and a biased roller, a fur brush, or the like is used. At this time, if the toner is difficult to be cleaned, the toner is filmed due to contact with the intermediate transfer member. Further, when the toner removed by the roller is scraped from the roller by the metal plate, the toner is fused to the metal plate, resulting in a scraping defect. In particular, in order to improve the glossiness of color images and the highly translucent color fixability, it is more likely to occur with the use of a low softening binder resin or a toner to which a low melting point release agent is added.
[0132]
Therefore, by using the toner of this embodiment, the charging property of the toner can be stabilized, the charging property can be uniform, there is little background fogging, and the transfer can be prevented from being lost and high transfer efficiency can be obtained. It becomes. With regard to the cleaning property, the improvement of uniform dispersibility in the resin, good charging property, and the mold release property of the material make the cleaning property good and avoid filming and scraping defects.
[0133]
Further, in this embodiment, a plurality of movable image forming units each including a rotating photosensitive member and a developing unit having toners of different colors and forming toner images of different colors on the photosensitive member are formed in an annular shape. The image forming unit group is arranged, and the entire image forming unit group is rotated and moved, and the toner images of different colors formed on the photosensitive member are aligned and transferred onto the transfer material to form a color image. It is suitably used for a color electrophotographic apparatus.
[0134]
Since the image forming unit is configured so that the entire unit revolves while the photosensitive member and the developing roller rotate, the toner temporarily contacts and leaves the developing roller and the supply roller in the developing unit. However, if the rising property of charging is poor, it causes ground fogging.
[0135]
Further, since the toner moves violently up and down by the rotation of the image forming unit, toner spills easily from the seal portion. Therefore, it is necessary to reinforce the seal at the seal portion, and a fusing phenomenon occurs. It becomes a lump and causes black and white streak image noise.
[0136]
In addition, there always occurs a situation in which the waste toner that has been cleaned from the photoconductor and collected from the photoconductor is repeatedly attached to and detached from the photoconductor. When the waste toner is repeatedly brought into contact with and separated from the photoreceptor, filming on the photoreceptor becomes remarkably easy to occur, which causes a reduction in the life of the photoreceptor.
[0137]
Therefore, by using the toner of this embodiment, the rising property of charging of the toner is stabilized, the toner has a uniform charging property, and the occurrence of background fogging at the initial stage of development can be suppressed. Due to the improvement of uniform dispersibility in the resin, good chargeability, and the releasability of the material, no fusing phenomenon or black or white streak image noise is observed in the image forming unit. Further, it is possible to prevent filming of the photoreceptor due to repeated contact and separation of the waste toner with the photoreceptor.
[0138]
Further, in this embodiment, a transfer material is inserted between the image carrier and the conductive elastic roller, and a transfer bias voltage is applied to the conductive elastic roller so that the toner image on the image carrier is subjected to electrostatic force. And preferably used in an electrophotographic apparatus including a toner transfer system for transferring to a transfer material. Since this toner transfer system is contact transfer, a mechanical force other than electric force acts on the transfer, and the reverse polarity toner adhering to the surface of the photoreceptor that should not be transferred is transferred or passed through. The toner adhering to the surface of the photoconductor when not in paper may contaminate the transfer roller surface and contaminate the back surface of the transfer paper.
[0139]
Therefore, the use of the toner of the present embodiment suppresses toner aggregation, prevents overcharging, stabilizes the chargeability, prevents voids during transfer, and enables high transfer efficiency. . Further, it is possible to prevent filming on the transfer body and the photoconductor, and to prevent the transfer paper from being contaminated by unnecessary toner particles. In addition, scratches and filming on the transfer roller surface can be prevented, and image defects can also be prevented.
[0140]
Further, in this embodiment, an electrophotography having a basic structure of a cleanerless process in which the following charging, exposure, and development processes are performed without having a cleaning process step of recovering toner remaining on the photoreceptor after the transfer process by cleaning. It is preferably used for an apparatus.
[0141]
By using the toner of this embodiment, toner aggregation can be suppressed, overcharging can be prevented, charging stability can be stabilized, and high transfer efficiency can be obtained. Further, the improvement in uniform dispersibility in the resin, good chargeability, and the releasability of the material make it possible to recover the toner remaining in the non-image area during development. For this reason, there is no development memory in which the image pattern in front of the non-image portion remains.
[0142]
Further, the present embodiment is suitably used for an electrophotographic apparatus including a fixing process in which a belt-type fixing medium is used as a means for fixing toner. As the belt, a heat resistant belt such as a nickel electroformed belt or a polyimide belt having heat resistance and deformability is used. In order to improve releasability, silicone rubber, fluororubber, or fluororesin is used as the surface layer. Up to now, a release oil has been applied to these fixing belts to prevent offset. It is no longer necessary to apply release oil with toner having releasability without using oil. However, if the release oil is not applied, it is easy to be charged, and if an unfixed toner image comes close to the belt, toner jump may occur due to the influence of charging. It tends to occur especially at low temperatures and low humidity. In addition, when the toner is added with a certain high molecular weight component to prevent high temperature offset and has a certain amount of elastic element, the paper with a thin vertical line pattern of the toner is separated from the belt with a large curvature at the leading edge. There may be a tip offset that is carried by the belt. Compared to the conventional rigid fixing roller, the elastic belt type has a problem in that the life is reduced due to scratches due to oillessness.
[0143]
Therefore, by using the toner of this embodiment, it is possible to prevent the occurrence of offset without using oil and to obtain high color translucency. Further, the toner can be prevented from being overcharged, and the toner can be prevented from flying due to the charging action with the belt. Further, it can be prevented by the molecular weight distribution and slipperiness effect of the offset toner that the tip part is brought to the belt when being separated from the belt.
[0144]
Examples of the pigment used in this embodiment include carbon black, iron black, graphite, nigrosine, azo dye metal complexes, C.I. I. Acetoacetic acid arylamide monoazo yellow pigments such as CI Pigment Yellow 1,3,74,97,98; I. Acetoacetic acid arylamide disazo yellow pigments such as C.I. Pigment Yellow 12, 13, 14, and 17; I. Solvent Yellow 19, 77, 79, C.I. I. Disperse Yellow 164, C.I. I. Red pigments such as CI Pigment Red 48, 49: 1, 53: 1, 57, 57: 1, 81, 122, 5; I. Red dyes such as Solvent Red 49, 52, 58, 8; I. One or two or more kinds of blue dyed pigments of phthalocyanine and derivatives thereof such as Pigment Blue 15: 3 are blended. The addition amount is preferably 3 to 8 parts by weight with respect to 100 parts by weight of the binder resin.
[0145]
Further, the volume average particle diameter of the toner is 3 to 11 μm, preferably 3 to 9 μm, more preferably 3 to 6 μm. If it is larger than 11 μm, the resolution is lowered and high image quality cannot be obtained, and if it is smaller than 3 μm, toner aggregation becomes strong and background fogging increases.
[0146]
The volume average particle size of the fixing aid is 1 to 10 μm, preferably 2 to 8 μm, more preferably 2 to 5 μm.
[0147]
Further, it is preferable that the variation coefficient of the volume particle size distribution of the toner is 15 to 35% and the variation coefficient of the number particle size distribution is 20 to 40%. More preferably, the variation coefficient of the volume particle size distribution is 15 to 30%, the variation coefficient of the number particle size distribution is 20 to 35%, and more preferably, the variation coefficient of the volume particle size distribution is 15 to 25%, the number particle size. The coefficient of variation of the distribution is 20-30%.
[0148]
The coefficient of variation is the standard deviation of the toner particle size divided by the average particle size. This is based on the particle diameter measured using a Coulter counter (Coulter). The standard deviation is expressed as the square root of the value obtained by dividing the square of the difference from the average value of each measured value when (n-1) is measured when n particle systems are measured.
[0149]
In other words, the coefficient of variation refers to the degree of spread of the particle size distribution, and if the coefficient of variation of the volume particle size distribution is less than 15% or the coefficient of variation of the number particle size distribution is less than 20%, it is difficult to produce, This will increase costs. If the coefficient of variation of volume particle size distribution is greater than 35% or the coefficient of variation of number particle size distribution is greater than 40%, the toner cohesion becomes stronger and the filming on the photoconductor occurs when the particle size distribution is broad. It becomes easy to do.
[0150]
The toner is prepared through steps of premixing, melt-kneading, pulverization and classification, and external addition.
[0151]
The premixing process is a process in which the binder resin and the additive to be dispersed in the binder resin are uniformly dispersed by a mixer equipped with stirring blades. As the mixer, a known mixer such as a super mixer (manufactured by Kawada Seisakusho), a Henschel mixer (manufactured by Mitsui Miike Kogyo Co., Ltd.), a PS mixer (manufactured by Shinko Pantech Co., Ltd.) or a Ladige mixer is used.
[0152]
FIG. 1 is a schematic perspective view of the toner melt-kneading process, FIG. 2 is a plan view, FIG. 3 is a front view, and FIG. 4 is a side view. 601 is a toner raw material supply unit, 602 is a roll (RL1), 603 is a roll (RL2), 604 is a molten film of toner wound on the roll (RL1), and 602-1 is a front half of the roll (RL1). (Upstream part in the raw material conveyance direction), 602-2 is the latter half part of the roll (RL2) (downstream part in the raw material conveyance direction), and 605 is a heat medium for heating the first half part 602-1 of the roll (RL1). 606, a heat medium outlet for heating the first half 602-1 of the roll (RL1), 607, a medium inlet for heating or cooling the latter half 602-2 of the roll (RL1), 608 Is a medium outlet for heating or cooling the latter half portion 602-2 of the roll (RL1), 609 is a medium inlet for heating or cooling the roll (RL2) 603, and 610 is for heating the roll (RL2) 603 The outlet of the cooled medium, 611 depth spiral grooves of the roll surface is about 2 to 10 mm, is 612 a toner reservoir is formed between rolls. The spiral groove 611 is preferable for smoothly conveying the material from the right end of the raw material input portion to the left end of the discharge portion when the toner is kneaded.
[0153]
The toner raw material is dropped from the opening 614 to the vicinity of the end on the roll (RL1) 602-1 side as indicated by an arrow 615 while being transferred from the fixed amount feeder to the raw material supply feeder 613. The length of the opening of the supply feeder is represented by 616. This length is preferably 1/2 to 4 times the roll radius. If it is short, the amount of the material to be dropped will drop rapidly from the gap between the two rollers before the material to be melted. If the length is too long, the raw material is separated during conveyance with the raw material feeder, and uniform dispersion cannot be obtained.
[0154]
Further, the drop position is dropped to a point in the range of 20 ° to 80 ° from the point at which the two rolls (RL1) 602 are closest to each other as shown by the arrows in FIG. If the angle is smaller than 20 °, the amount of falling from the gap between the two rolls increases rapidly. When falling at 80 ° or more, the toner powder rises more and contaminates the surrounding area. The cover 617 is installed so as to cover an area wider than the opening length 616. In FIG. 3, the illustration of the cover is omitted.
[0155]
The toner raw material drops from the opening 614 while being transmitted through the supply feeder 613 from the fixed amount feeder 601. The dropped toner material is dropped near the end of the roll (RL1) 602-1 side. Then, the resin melts due to the heat of 602-1 and the compressive shear force between the roll (RL2) 603 and winds around the front half 602-1 of the roll (RL1). The state extends to the end of the rear half 602-2 of the roll (RL1) and is heated or cooled at a lower temperature than the front half 602-1 of the roll (RL1). Is peeled off as a toner soul. During the above process, the roll 603 is cooled to room temperature or lower. The clearance between the roll (RL1) 602 and the roll (RL2) 603 is 0.1 to 0.9 mm. In this example, the raw material input was 10 kg / h, the rolls (RL1) and (RL2) had a diameter of 140 mm and a length of 800 mm.
[0156]
The resulting toner mass is roughly pulverized with a cutter mill, etc., and then finely pulverized with a jet mill (for example, IDS pulverizer, Nippon Pneumatic Industry), and if necessary, fine powder particles are cut with an airflow classifier. Thus, toner particles (toner base particles) having a desired particle size distribution are obtained. Then, toner particles (toner base particles) having a volume average particle diameter in the range of 3 to 6 μm are obtained by classification.
[0157]
The external addition treatment is a treatment in which an external additive such as silica is mixed with the toner particles (toner base particles) obtained by the classification. For this, a known mixer such as a Henschel mixer or a super mixer is used.
[0158]
Next, the present invention will be described in more detail with reference to examples.
[0159]
Table 1 shows the characteristics of the binder resin used in the examples. As the resin, a polyester resin mainly composed of bisphenol A propyl oxide adduct, terephthalic acid, trimellitic acid, succinic acid and fumaric acid was used, and a resin whose thermal characteristics were changed depending on the blending ratio and polymerization conditions was used.
[0160]
[Table 1]

[0161]
Mnf is the number average molecular weight of the binder resin, Mwf is the weight average molecular weight of the binder resin, Mzf is the Z average molecular weight of the binder resin, Wmf is the ratio of the weight average molecular weight Mwf to the number average molecular weight Mnf, Mwf / Mnf, and Wzf is The ratio Mzf / Mnf, AV of the Z-average molecular weight Mzf and the number-average molecular weight Mnf of the binder resin indicates the resin acid value.
[0162]
(Table 2) (Table 3) shows fixing aids used in this example and their physical properties.
[0163]
[Table 2]

[0164]
[Table 3]

[0165]
Table 4 shows the charge control agents used in this example.
[0166]
As a metal salt of a salicylic acid derivative, examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Etc. Examples of the metal Y include zinc, nickel, cobalt, copper, and chromium, and zinc and chromium are preferable. Examples of metal salts of benzylic acid derivatives include R¹~ R^FourAs the benzene ring and alkali metal X, lithium, sodium, potassium and the like can be mentioned, and potassium is preferred.
[0167]
[Table 4]

[0168]
Table 5 shows the external additive silica used in this example. The charge amount of silica is measured by the blow-off method of frictional charge with an uncoated ferrite carrier. Under an environment of 25 ° C. and 45% RH, 50 g of a carrier and 0.1 g of silica or the like are mixed in a 100 ml polyethylene container, and 100 minutes by longitudinal rotation.^-1After stirring at a speed of 5 minutes for 30 minutes, 0.3 g was collected and nitrogen gas 1.96 × 10 6 was collected.^Four(Pa) was blown for 60 seconds.
[0169]
For positive chargeability, the 5-minute value after stirring for 5 minutes is preferably +100 to +800 μC / g, and the 30-minute value after stirring for 30 minutes is preferably +50 to +400 μC / g. Silica having a charge amount at 30 minutes of 40% or more of the charge amount at 5 minutes is preferable. If the rate of decrease is large, the change in charge amount during long-term continuous use is large, and a constant image cannot be maintained.
[0170]
For negative chargeability, the 5-minute value is preferably −100 to −800 μC / g, and the 30-minute value is preferably −50 to −600 μC / g. Highly charged silica can function with a small amount of addition.
[0171]
[Table 5]

[0172]
Table 6 shows the pigments used in this example.
[0173]
[Table 6]

[0174]
Table 7 and Table 8 show the kneading conditions in this example.
[0175]
Tm is the softening point of the binder resin, Tw is the melting point of the fixing aid, Trl (C) is the heating temperature of the first half of the roll (RL1), Trk1 (C) is the heating temperature of the second half of the roll (RL1), Tr2 (° C.) The heating temperature of the roll (RL2), Rw1 is the rotation speed of the roll (RL1), Rw2 is the rotation speed of the roll (RL2), and the load current value during rotation of the roll (RL1) is Dr1. The load current value is indicated as Dr2.
[0176]
[Table 7]

[0177]
[Table 8]

[0178]
  (Table 9)BookThe toner material composition used in the examples is shown.The toner samples TM1, TM2, TM3, TY1, TY2, TY3, TC1, TC2, TC3, TB1, TB2 and TB3 are reference examples.
[0179]
[Table 9]

[0180]
Each toner was prototyped such that the weight average particle size was 6 to 7 μm, the volume particle size distribution variation coefficient was 20 to 25%, and the number particle size distribution variation coefficient was 25 to 30%.
[0181]
The blending ratio of pigment, charge control agent, and fixing aid is shown in parentheses in the blending ratio (parts by weight) with respect to 100 parts by weight of the binder resin. The external additive indicates a blending amount (parts by weight) with respect to 100 parts by weight of the toner base. The external addition process was performed in FM20B with a stirring blade Z0S0 type, a rotational speed of 2000 rpm, a processing time of 5 min, and an input amount of 1 kg.
[0182]
Table 10 and Table 11 show the molecular weight characteristics of the toner after the kneading treatment in this example. The toner was evaluated with TM toner of magenta toner. Similar results are obtained with yellow, cyan, and black toners. Mnv is the number average molecular weight of the toner, Mwv is the weight average molecular weight of the toner, Wmv is the ratio of the weight average molecular weight Mwv of the toner to the number average molecular weight Mnv, Mwv / Mnv, and Wzv is the ratio of the Z average molecular weight Mzv of the toner to the number average molecular weight Mnv. Mzv / Mnv is shown.
[0183]
ML is a molecular weight value showing a molecular weight maximum peak on the low molecular weight side in the molecular weight distribution, MH is a molecular weight value showing a molecular weight maximum peak on the high molecular weight side, Sm is Hb / Ha, SK1 is M10 / M90, and SK2 is (M10-M90). / M90 is shown.
[0184]
[Table 10]

[0185]
[Table 11]

[0186]
5 to 11 show molecular weight distribution characteristics.
[0187]
5a and 5b show the molecular weight distribution characteristics of the binder resin PES-1 and the toner TM-1, respectively. FIGS. 6a and 6b show the molecular weight distribution characteristics of the binder resin PES-2 and the toner TM-2, respectively. 7b shows the molecular weight distribution characteristics of the binder resin PES-3 and toner TM-3, FIGS. 8a and 8b show the molecular weight distribution characteristics of the binder resin PES-4 and toner TM-4, respectively, and FIGS. 9a and 9b show the binding characteristics. The molecular weight distribution characteristics of the resin pes-5 and the toner tm-5 are shown.
[0188]
In the binder resin PES-1, 3 × 10^FourThe above high molecular weight components are present in an area ratio of 5% or more with respect to the entire binder resin molecular weight distribution. 3 × 10^Five~ 9x10⁶The high molecular weight component is 1% or more by area ratio with respect to the entire binder resin molecular weight distribution. Similarly, PES-2, 3, 4 are also 3 × 10^FourThe above high molecular weight components are present in an area ratio of 5% or more with respect to the entire binder resin molecular weight distribution. 3 × 10^Five~ 9x10⁶The high molecular weight component is 1% or more by area ratio with respect to the entire binder resin molecular weight distribution. But in pes-5, 3x10^FourThe presence of the above high molecular weight components is 5% or less in area ratio with respect to the entire binder resin molecular weight distribution, and 3 × 10^Five~ 9x10⁶There is no high molecular weight component.
[0189]
It can be seen that the toner is molecularly cut by kneading and appears as a peak or shoulder on the polymer component side. That is, the component that inhibits the translucency disappears due to the cutting, and a steep inclination appears on the polymer side, which is a factor that maintains the offset resistance without inhibiting the translucency. For toner TM-1, 3 × 10^FiveThe amount of the above high molecular weight component is 5% or less in terms of area with respect to the entire toner molecular weight distribution, and is 1 × 10⁶The above high molecular weight components are hardly contained. Similarly, TM-2, 3 and 4 are 3 × 10^FiveThe amount of the above high molecular weight component is 5% or less in terms of area with respect to the entire toner molecular weight distribution, and is 1 × 10⁶The above high molecular weight components are hardly contained.
[0190]
10 and 11 show examples of molecular weight distribution characteristics. FIG. 11 schematically shows M10 and M90 having a characteristic that a steep molecular weight peak is formed on the polymer component side. The height of the maximum peak of the molecular weight distribution is 100%. FIG. 10 schematically shows M10 and M90 of the molecular weight distribution characteristic of the toner TM-3. A shoulder shape appears on the polymer component side, and the height of the apex of the shoulder of the shoulder portion is taken as a reference of 100%. This is because the high molecular weight component of the binder resin PES3 is molecularly cut by kneading and appears as a shoulder on the high molecular component side.
[0191]
When the peak height of the distribution on the polymer side is 100%, a molecular weight curve in a region larger than the molecular weight value corresponding to the maximum peak or shoulder, that is, a region where the slope of the molecular weight distribution curve in this region is negative, In other words, in the region on the right side of the distribution curve, when the molecular weight distribution maximum peak or shoulder height is 100%, the molecular weight corresponding to 90% of the molecular weight maximum peak or shoulder height is M90, the molecular weight maximum peak or shoulder. The molecular weight corresponding to 10% of the height is M10. Here, the value of M10 / M90 (the slope of the molecular weight distribution curve) can quantify the state of molecular cleavage of the ultrahigh molecular weight component. When the value of M10 / M90 is small, the slope of the molecular weight distribution curve is steep, and the component that inhibits the translucency is eliminated by cutting and has high translucency. Furthermore, the peak appearing on the polymer side contributes to the offset resistance.
[0192]
FIG. 16 shows the molecular weight distribution characteristics of the fixing aid WF-1. The horizontal axis is the logarithm of molecular weight.
[0193]
Example 1
FIG. 12 is a cross-sectional view showing the configuration of an electrophotographic apparatus for forming a full-color image used in this embodiment. In FIG. 12, reference numeral 1 denotes an exterior casing of a color electrophotographic printer, and the right end face side in the figure is the front face. Reference numeral 1A denotes a printer front plate. The front plate 1A can be freely opened and closed with respect to the printer outer casing 1 around the hinge shaft 1B on the lower side as shown by a dotted line, and can be raised and closed as shown by a solid line. The internal transfer belt unit 2 is attached to and detached from the printer, and internal inspection and maintenance of the printer, such as when a paper jam occurs, is performed by tilting and opening the front plate 1A to largely release the printer interior. The attachment / detachment operation of the intermediate transfer belt unit 2 is designed to be perpendicular to the direction of the rotation axis of the photosensitive member.
[0194]
The configuration of the intermediate transfer belt unit 2 is shown in FIG. The intermediate transfer belt unit 2 includes a unit housing 2a, an intermediate transfer belt 3, a first transfer roller 4 made of a conductive elastic body, a second transfer roller 5 made of an aluminum roller, and a tension roller 6 for adjusting the tension of the intermediate transfer belt 3. A belt cleaner roller 7 for cleaning the toner image remaining on the intermediate transfer belt 3, a scraper 8 for scraping off the toner collected on the cleaner roller 7, waste toner reservoirs 9 a and 9 b for collecting the collected toner, and the intermediate transfer belt 3. It includes a position detector 10 that detects the position of. As shown in FIG. 12, the intermediate transfer belt unit 2 is detachably attached to a predetermined storage portion in the printer outer casing 1 by opening the printer front plate 1 </ b> A as shown by a dotted line.
[0195]
The intermediate transfer belt 3 is used by kneading a conductive filler in an insulating resin and forming a film with an extruder. In the present example, a film obtained by adding 5 parts by weight of conductive carbon (for example, ketjen black) to 95 parts by weight of polycarbonate resin (for example, Iupilon Z300, manufactured by Mitsubishi Gas Chemical) as the insulating resin was used. The surface was coated with a fluorine resin. The thickness of the film is about 350 μm and the resistance is about 10⁷-10⁹Ω · cm. Here, the use of the intermediate transfer belt 3 in which a conductive filler is kneaded into a polycarbonate resin and used as a film can effectively prevent the intermediate transfer belt 3 from being loosened or accumulated due to long-term use. The reason for this is that the surface is coated with a fluororesin so that toner filming on the surface of the intermediate transfer belt due to long-term use can be effectively prevented.
[0196]
This intermediate transfer belt 3 is made of a film based on a semiconductive urethane having a thickness of 100 μm and having an endless belt shape.⁶-10⁸It is configured to be wound around a first transfer roller 4, a second transfer roller 5 and a tension roller 6 formed of urethane foam subjected to low resistance treatment so as to have a resistance of Ω · cm, and to be movable in the direction of the arrow. Here, the peripheral length of the intermediate transfer belt 3 is slightly longer than half of the peripheral length of the photosensitive drum (diameter 30 mm), which will be described later, in the length (298 mm) in the longitudinal direction of A4 paper, which is the maximum paper size ( 62 mm) is set to 360 mm.
[0197]
When the intermediate transfer belt unit 2 is mounted on the printer main body, the first transfer roller 4 is moved to the photoreceptor 11 (shown in FIG. 13) via the intermediate transfer belt 3 by about 9.8 × 10.^Four(N / m²The second transfer roller 5 is pressed against the third transfer roller 12 (shown in FIG. 13) having the same configuration as the first transfer roller 4 via the intermediate transfer belt 3. . The third transfer roller 12 is configured to be driven to rotate by the intermediate transfer belt 3.
[0198]
The cleaner roller 7 is a belt cleaner roller that cleans the intermediate transfer belt 3. This is a configuration in which an AC voltage that electrostatically attracts toner is applied to a metallic roller. The cleaner roller 7 may be a rubber blade or a conductive fur brush to which a voltage is applied.
[0199]
In FIG. 12, in the center of the printer, four sets of fan-shaped image forming units 17Bk, 17Y, 17M, and 17C for each color of black, cyan, magenta, and yellow constitute an image forming unit group 18, as shown in the figure. It is arranged in an annular shape. Each of the image forming units 17Bk, 17Y, 17M, and 17C is detachable at a predetermined position of the image forming unit group 18 by opening the printer upper surface plate 1C around the hinge shaft 1D. When the image forming units 17Bk, 17Y, 17M, and 17C are properly mounted in the printer, the mechanical drive system and the electric circuit system on both the image forming unit side and the printer side are mutually coupled members (not shown). Are combined through mechanical and electrical integration.
[0200]
The image forming units 17Bk, 17C, 17M, and 17Y arranged in an annular shape are supported by a support (not shown) and are driven by a moving motor 19 as a moving means as a whole, and are fixed and do not rotate. It is comprised so that rotation around the shaft 20 of a shape is possible. Each image forming unit can be positioned at an image forming position 21 facing the second transfer roller 4 that sequentially supports the above-described intermediate transfer belt 3 by rotational movement. The image forming position 21 is also an exposure position by the signal light 22.
[0201]
Each of the image forming units 17Bk, 17C, 17M, and 17Y is composed of the same constituent members except for the developer contained therein, so that the black image forming unit 17Bk will be described for simplifying the description, and for other colors. The description of the unit is omitted.
[0202]
FIG. 14 shows an image forming unit. Reference numeral 11 denotes a photoconductor, and 30 denotes a developing roller having a diameter of 18 mm made of silicone rubber having a JIS-A hardness of 60 °, which is pressed against the photoconductor with a force of 21 N and rotates in the direction of the arrow. Reference numeral 31 denotes a supply roller made of a urethane sponge having a diameter of 14 mm, and supplies the toner in the toner hopper to the developing roller. A metal blade 32 forms a toner layer on the developing roller. Reference numeral 33 denotes a power source to which 230V direct current and 500V (pp) alternating current voltage having a frequency of 1 kHz are applied. Reference numeral 24 denotes a φ12 mm charging roller made of epichlorohydrin rubber, to which a DC bias of −1 kV is applied. Charge the photoreceptor surface to -450V. 26 is a developer reservoir, 34 is a cleaner, 27 is waste toner, and 28Bk is black toner.
[0203]
Reference numeral 35 in FIG. 12 denotes a laser beam scanner unit disposed on the lower side of the printer outer casing 1, and includes a semiconductor laser (not shown), a scanner motor 35a, a polygon mirror 35b, a lens system 35c, and the like. The pixel laser signal light 22 corresponding to the time-series electric pixel signal of the image information from the laser beam scanner unit 35 passes through the optical path window 36 formed between the image forming units 17Bk and 17Y, and a part of the shaft 20 Is incident on the fixed mirror 38 in the shaft 20 through the window 37 opened in the first, and is reflected to enter the image forming unit 17Bk almost horizontally from the exposure window 25 of the image forming unit 17Bk at the image forming position 21; The light passes through the passage between the developer reservoir 26 and the cleaner 34 disposed vertically in the image forming unit, enters the exposure portion on the left side surface of the photoconductor 11, and is scanned and exposed in the direction of the generatrix.
[0204]
Here, since the optical path from the optical path window 36 to the mirror 38 uses a gap between the adjacent image forming units 17Bk and 17Y, the image forming unit group 18 has almost no wasted space. Further, since the mirror 38 is provided in the central portion of the image forming unit group 18, it can be constituted by a single fixed mirror, and is simple and easy to align.
[0205]
Reference numeral 12 denotes a third transfer roller disposed on the inner side of the printer front plate 1A and above the paper feed roller 39. The printer front plate is located at the nip portion where the intermediate transfer belt 3 and the third transfer roller 12 are in pressure contact with each other. A paper transport path is formed so that the paper is fed by a paper feed roller 39 provided at the lower part of 1A.
[0206]
Reference numeral 40 denotes a paper feed cassette provided so as to protrude outward on the lower side of the printer front plate 1A, and a plurality of paper S can be set simultaneously. 41a and 41b are paper conveyance timing rollers, 42a is a fixing roller, 42b is a pressure roller, 42c is a fixing belt made of fluoro rubber, 42d is a heating medium roller, and 43 is provided between the third transfer roller 12 and the fixing roller pair. The paper guide plates 44a and 44b are a paper discharge roller pair disposed on the paper exit side of the fixing roller pair.
[0207]
FIG. 15 shows the fixing process. A belt 42c is placed between the fixing roller 42a and the heat roller 42d. A predetermined load is applied between the fixing roller 42a and the pressure roller 42b, and a nip is formed between the belt and the pressure roller. A heater is provided inside the heat roller 42d, and a temperature sensor 51 is disposed on the outer surface.
[0208]
The pressure roller 42 b is pressed against the fixing roller 42 a by a pressure spring 52. The recording material 54 having the toner 53 moves along the guide plate 55.
[0209]
The fixing roller 42a as a fixing member is a silicone rubber having a rubber hardness (JIS-A) of 20 degrees according to JIS standard on the surface of an aluminum hollow roller core 56 having a length of 250 mm, an outer diameter of 14 mm, and a thickness of 1 mm. An elastic layer 57 having a thickness of 3 mm is provided. A silicone rubber layer 58 is formed thereon with a thickness of 3 mm, and the outer diameter is about 20 mm. It receives a driving force from a driving motor (not shown) and rotates at 100 mm / s.
[0210]
The heat roller 42d is made of an aluminum hollow pipe having a thickness of 1 mm and an outer diameter of 20 mm. A 700 W lamp heater 58 for heating was provided inside, and the surface temperature of the fixing roller was controlled to 170 ° C. using a thermistor. Further, when fixing the OHP image, the fixing was performed at a half speed of 50 mm / s.
[0211]
The pressure roller 42b as a pressure member has a length of 250 mm and an outer diameter of 20 mm. This is provided with an elastic layer 60 having a thickness of 2 mm made of silicone rubber having a rubber hardness (JIS-A) of 55 degrees according to JIS standards on the surface of a hollow roller metal core 59 made of aluminum having an outer diameter of 16 mm and a thickness of 1 mm. . The pressure roller 42b is rotatably installed, and a nip width of 5.0 mm is formed between the pressure roller 42b and the fixing roller 1 by a spring-loaded spring 52 on one side 147N.
[0212]
Each of the image forming units 17Bk, 17C, 17M, and 17Y and the intermediate transfer belt unit 2 is provided with a waste toner reservoir.
[0213]
The operation will be described below.
[0214]
Initially, in the image forming unit group 18, as shown in FIG. 12, the black image forming unit 17 </ b> Bk is at the image forming position 21. At this time, the photoconductor 11 is in opposed contact with the first transfer roller 4 via the intermediate transfer belt 3.
[0215]
In the image forming step, black signal light is input to the image forming unit 17Bk by the laser beam scanner unit 35, and image formation with black toner is performed. At this time, the image forming speed of the image forming unit 17Bk (60 mm / s equal to the peripheral speed of the photosensitive member) and the moving speed of the intermediate transfer belt 3 are set to be the same. 4, the black toner image is transferred to the intermediate transfer belt 3. At this time, a DC voltage of +1 kV was applied to the first transfer roller. Immediately after all the black toner images have been transferred, the image forming units 17Bk, 17C, 17M, and 17Y are driven by the moving motor 19 as a whole as the image forming unit group 18 and rotated and moved in the direction of the arrow in the figure. The image forming unit 17C rotates 90 degrees and stops at a position where it reaches the image forming position 21. During this time, the toner hopper 26 and the cleaner 34 other than the photoconductor of the image forming unit are located on the inner side of the rotating arc at the tip of the photoconductor 11, so that the intermediate transfer belt 3 does not contact the image forming unit.
[0216]
After the image forming unit 17C arrives at the image forming position 21, the laser beam scanner unit 35 inputs the signal light 22 to the image forming unit 17C with a cyan signal and forms and transfers a cyan toner image as before. Is called. By this time, the intermediate transfer belt 3 is rotated once, and the writing timing of the cyan signal light is controlled so that the next cyan toner image is in position with the previously transferred black toner image. During this time, the third transfer roller 12 and the cleaner roller 7 are slightly separated from the intermediate transfer belt 3 so that the toner image on the transfer belt is not disturbed.
[0217]
The same operation as described above was performed for magenta and yellow, and four color toner images were positioned and superimposed on the intermediate transfer belt 3 to form a color image. After the transfer of the last yellow toner image, the four color toner images are collectively transferred to the paper fed from the paper feed cassette 40 at the same timing by the action of the third transfer roller 12. At this time, the second transfer roller 5 was grounded, and a DC voltage of +1.5 kV was applied to the third transfer roller 12. The toner image transferred to the paper was fixed by a pair of fixing rollers 42a and 42b. The paper was then discharged out of the apparatus through a pair of discharge rollers 44a and 44b. The remaining transfer toner remaining on the intermediate transfer belt 3 was cleaned by the action of the cleaner roller 7 to prepare for the next image formation.
[0218]
Next, the operation in the monochrome mode will be described. In the single color mode, first, the image forming unit of a predetermined color moves to the image forming position 21. Next, image formation of a predetermined color and transfer to the intermediate transfer belt 3 are performed in the same manner as before, and this time, after the transfer, continues as it is, onto the sheet fed from the paper feed cassette 40 by the next third transfer roller 12. The image was transferred and fixed as it was.
[0219]
Table 12 shows the results of image output using the electrophotographic apparatus shown in FIG.
[0220]
[Table 12]

[0221]
With this electrophotographic apparatus, when the image was produced using the toner produced as described above, the solid black image was uniform with no disturbance of the horizontal line, toner scattering, character omission, etc., and 16 lines / mm. An image with extremely high resolution and high image quality that reproduced the image line was obtained, and an image with a high density of 1.3 or higher was obtained. In addition, the ground cover of the non-image area did not occur. Further, even in the long-term durability test of 10,000 sheets, both the fluidity and the image density showed a stable characteristic with little change. In addition, the uniformity when the entire solid image was taken at the time of development was also good. There is no development memory. Also, in the transfer, the void is at a level that causes no practical problem, and the transfer efficiency is 90%. Further, the filming of the toner onto the photosensitive member and the intermediate transfer belt was at a level that causes no problem in practice. No scraping defects occurred in the cleaning of the intermediate transfer belt. Also, there is almost no toner disturbance or toner skipping during fixing. Further, even in the cleaner process in which the remaining toner at the time of transfer is recovered by development without using a cleaning blade, the recovery can be performed smoothly, and the history of the previous image does not remain. However, the toners at tm5, ty5, and tc5 caused filming of the photosensitive member and transfer loss, and a lot of fogging occurred. Filming of the intermediate transfer belt and defective cleaning scraping also occurred. When the entire solid image was taken at the time of development, the second half was blurred. Toner skip occurred during fixing.
[0222]
Next (Table 13), the amount of adhesion to OHP paper is 1.2 g / cm.²The solid image was subjected to a non-offset property test with a fixing device using a belt having a process speed of 110 mm / s and no oil applied. No OHP jam occurred at the fixing nip. In the full-solid image of plain paper, the offset did not occur at all up to the 122,000th sheet. Even if the oil is not applied with a silicon or fluorine-based fixing belt, the surface deterioration of the belt is not observed.
[0223]
The transmittance and the offset property at high temperature were evaluated. The process speed was 55 mm / s, the transmittance at 180 ° C. was measured with a spectrophotometer U-3200 (Hitachi), and the light transmittance at 700 nm was measured. The results of fixing property, offset resistance and storage stability are shown.
[0224]
[Table 13]

[0225]
The OHP translucency was 80% or more, and the non-offset temperature range was 40 to 60 K. The fixing roller using no oil showed good fixing properties. Also, almost no aggregation was observed in the storage stability at 60 ° C. for 5 hours. However, the toner of tm5 was hardened in the storage stability test, and the non-offset temperature range was narrow.
[0226]
【The invention's effect】
As described above, according to the present invention, in the molecular weight distribution in GPC (gel permeation chromatography), the weight average molecular weight is 1000 to 6000, the Z average molecular weight is 1500 to 9000, and the ratio of the weight average molecular weight to the number average molecular weight (weight). (Average molecular weight / number average molecular weight) is 1.1 to 3.8, and the ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is 1.5 to 6.5, 1 × 10.^Three~ 1x10^FourHaving at least one maximum molecular weight peak in the region of 5 and obtained by a reaction with a long-chain alkyl alcohol having at least 5 to 100 carbon atoms, an unsaturated polyvalent carboxylic acid or an anhydride thereof, and a hydrocarbon wax. -80 mg KOH / g, melting point 90-120 ° C., fixing agent having a penetration of 4 or less at 25 ° C. and a charge control agent in combination with a metal salt of a salicylic acid derivative or a metal salt of a benzyl acid derivative as a binder resin The added composition prevents thermal fusing and aggregation of the toner even when used in a contact-type one-component development method, and prevents image deterioration due to overcharging in long-term continuous use and fogging under low temperature and low humidity. It has a uniform charge distribution, and it is possible to continue outputting stable image characteristics even after long-term use.
[0227]
By using an electrophotographic method using a conductive elastic roller or an intermediate transfer member, it is possible to prevent hollowing out and scattering during transfer and to obtain high transfer efficiency. Filming of the photosensitive member and the intermediate transfer member can be prevented even during long-term use under high humidity. The cleaning property of the intermediate transfer member can be improved. Even in the cleaning process that does not use the cleaning blade, the transfer residual toner can be collected smoothly, and the history of the previous image can be prevented from remaining.
[0228]
Even if no oil is applied by a silicon or fluorine-based fixing means (roller or belt), the offset property can be prevented while maintaining high OHP translucency. In addition, even when used for a long time, good non-offset property can be maintained without causing a belt surface deterioration phenomenon.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a toner melt-kneading process used in an embodiment of the present invention.
FIG. 2 is a plan view of a toner melt-kneading process used in an embodiment of the present invention.
FIG. 3 is a front view of a toner melt kneading process used in an embodiment of the present invention.
FIG. 4 is a cross-sectional view of a toner melt kneading process used in an embodiment of the present invention.
FIG. 5 is a graph showing molecular weight distribution characteristics of a binder resin and a toner according to an embodiment of the present invention.
FIG. 6 is a graph showing molecular weight distribution characteristics of a binder resin and a toner according to an embodiment of the present invention.
FIG. 7 is a graph showing molecular weight distribution characteristics of a binder resin and a toner according to an embodiment of the present invention.
FIG. 8 is a graph showing molecular weight distribution characteristics of a binder resin and a toner according to an embodiment of the present invention.
FIG. 9 is a graph showing molecular weight distribution characteristics of a binder resin and a toner according to an embodiment of the present invention.
FIG. 10 is a graph showing molecular weight distribution characteristics of toner according to an embodiment of the present invention.
FIG. 11 is a graph showing molecular weight distribution characteristics of toner according to an embodiment of the present invention.
FIG. 12 is a cross-sectional view showing a configuration of an electrophotographic apparatus used in an example of the present invention.
FIG. 13 is a cross-sectional view showing a configuration of an intermediate transfer belt unit used in an embodiment of the present invention.
FIG. 14 is a cross-sectional view showing a configuration of a developing unit used in an embodiment of the present invention.
FIG. 15 is a cross-sectional view showing a configuration of a fixing unit used in an embodiment of the present invention.
FIG. 16 is a graph showing the molecular weight distribution characteristics of the fixing aid according to the embodiment of the present invention.
[Explanation of symbols]
2 Intermediate transfer belt unit
3 Intermediate transfer belt
4 First transfer roller
5 Second transfer roller
6 Tension roller
11 photoconductor
12 Third transfer roller
17Bk, 17C, 17M, 17Y Image forming unit
18 Image forming units
21 Image forming position
22 Laser signal light
35 Laser beam scanner
38 mirror
602 roll (RL1)
603 roll (RL2)
604 Molten film of toner wound on roll (RL1)
605 Heat medium inlet
606 Heat medium outlet

Claims (20)

It is obtained by reaction of at least a binder resin with 100 parts by weight of the binder resin, a long-chain alkyl alcohol having 5 to 100 carbon atoms, an unsaturated polycarboxylic acid or an anhydride thereof, and a hydrocarbon wax, In the molecular weight distribution in gel permeation chromatography (GPC), the weight average molecular weight is 1000 to 6000, the Z average molecular weight is 1500 to 9000, and the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.1. ˜3.8, the ratio of the Z average molecular weight to the number average molecular weight (Z average molecular weight / number average molecular weight) is 1.5 to 6.5, and the molecular weight is 1 × 10 ^{3 to} 3 × 10 ^4. 1 to 12 parts by weight of a fixing aid having a peak, an acid value of 5 to 80 mg KOH / g, a melting point of 90 to 120 ° C., and a penetration at 25 ° C. of 4 or less ;
0.5 to 5 parts by weight of a metal salt of a salicylic acid derivative represented by (Chemical Formula 1) with respect to 100 parts by weight of the binder resin
A toner base containing 0.5 to 5 parts by weight of a metal salt of a benzylic acid derivative represented by (Chemical Formula 2) with respect to 100 parts by weight of the binder resin;
A toner characterized in that silica having a triboelectric charging property having a positive charging property is externally added to the toner base .

(R ¹ and R ⁴ represent a hydrogen atom, an alkyl group or an aromatic ring which may have a substituent, R ² and R ³ represent an aromatic ring which may be substituted. X represents an alkali metal) The weight-average molecular weight of the THF-soluble GPC is 10,000 to 200,000, the Z-average molecular weight is 20,000 to 500,000, the ratio of the weight-average molecular weight to the number-average molecular weight (weight-average molecular weight / number-average molecular weight) is 3 to 100, The ratio of Z-average molecular weight to number-average molecular weight (Z-average molecular weight / number-average molecular weight) is 10 to 2000, has at least one molecular weight maximum peak in the region of 2 × 10 ^{3 to} 3 × 10 ⁴ , and has a high molecular weight region A polyester resin having 5% or more of a molecular weight component of 3 × 10 ⁴ or more as a component present in the binder resin and an acid value of 1 to 40 mgKOH / g;
Gel permeation chromatography (GPC) is obtained by reacting with 100 parts by weight of the polyester resin with a long-chain alkyl alcohol having at least 5 to 100 carbon atoms, an unsaturated polycarboxylic acid or anhydride thereof, and a hydrocarbon wax. ), The weight average molecular weight is 1000 to 6000, the Z average molecular weight is 1500 to 9000, the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.1 to 3.8, Z The ratio of the average molecular weight to the number average molecular weight (Z average molecular weight / number average molecular weight) is 1.5 to 6.5, and the molecular weight is 1 × 10 ^{3 to} 3 × 10 ^4. 1 to 12 parts by weight of a fixing aid having a value of 5 to 80 mg KOH / g, a melting point of 90 to 120 ° C., and a penetration of 4 or less at 25 ° C.
0.5 to 5 parts by weight of a metal salt of a salicylic acid derivative represented by (Chemical Formula 3) with respect to 100 parts by weight of the polyester resin
A toner base containing 0.5 to 5 parts by weight of a metal salt of a benzylic acid derivative represented by (Chemical Formula 4) with respect to 100 parts by weight of the polyester resin;
A toner characterized in that silica having a triboelectric charging property having a positive charging property is externally added to the toner base .

(R ¹ and R ⁴ represent a hydrogen atom, an alkyl group or an aromatic ring which may have a substituent, R ² and R ³ represent an aromatic ring which may be substituted. X represents an alkali metal) A toner is prepared through at least a kneading process step with a binder resin, a colorant, a fixing aid and other additives added as necessary, and the molecular weight distribution in GPC of the toner is a molecular weight of 2 × 10 ^{3 to} 3 ×. 10 ⁴ region having at least one molecular weight maximum peak, molecular weight 5 × 10 ⁴ to 1 × 10 ⁶ region having at least one molecular weight maximum peak or shoulder, weight average molecular weight of 8000 to 180,000, Z The average molecular weight is 18,000 to 450,000, the ratio of weight average molecular weight to number average molecular weight (weight average molecular weight / number average molecular weight) is 3 to 80, and the ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is The toner according to claim 1 , wherein the toner is 10 to 1,000. A toner is prepared through at least a kneading process step with a binder resin, a colorant, a fixing aid and other additives added as necessary, and the molecular weight distribution in GPC of the toner is 2 × 10 ^{3 to} 3 × 10 6. ⁴ region having at least one molecular weight maximum peak, 5 × 10 ⁴ to 1 × 10 ⁶ region having at least one molecular weight maximum peak or shoulder, 2 × 10 ^{3 to} 3 × 10 ⁴ region When the height of the existing molecular weight maximum peak is Ha and the height of the molecular weight maximum peak or shoulder existing in the region of 5 × 10 ⁴ to 1 × 10 ⁶ is Hb, Hb / Ha is 0.15 to 0.90. The toner according to claim 1 or 2 . A toner is prepared through at least a kneading process step with a binder resin, a colorant, a fixing aid and other additives added as necessary, and the molecular weight distribution in GPC of the toner is a molecular weight of 2 × 10 ^{3 to} 3 ×. at least one molecular weight maximum peak in 10 ^fourth region has at least one molecular weight maximum peak or shoulder in a molecular weight region of 5 × 10 ⁴ to 1 × 10 ^6, in the region of molecular weight of from 5 × 10 ⁴ to 1 × 10 ⁶ In the molecular weight curve in the region larger than the molecular weight value corresponding to the maximum peak or shoulder of the existing molecular weight distribution, when the maximum peak or shoulder height of the molecular weight distribution is 1, the molecular weight maximum peak or shoulder height When the molecular weight corresponding to 90% is M90 and the molecular weight corresponding to 10% of the molecular weight maximum peak or shoulder height is M10, M10 / M90 The toner according to claim 1 or 2, wherein 0.5 to 8. A toner is prepared through at least a kneading process step with a binder resin, a colorant, a fixing aid and other additives added as necessary, and the molecular weight distribution in GPC of the toner is a molecular weight of 2 × 10 ^{3 to} 3 ×. at least one molecular weight maximum peak in 10 ^fourth region has at least one molecular weight maximum peak or shoulder in a molecular weight region of 5 × 10 ⁴ to 1 × 10 ^6, in the region of molecular weight of from 5 × 10 ⁴ to 1 × 10 ⁶ In the molecular weight curve in the region larger than the molecular weight value corresponding to the maximum peak or shoulder of the existing molecular weight distribution, when the maximum peak or shoulder height of the molecular weight distribution is 1, the molecular weight maximum peak or shoulder height When the molecular weight corresponding to 90% is M90 and the molecular weight corresponding to 10% of the molecular weight maximum peak or shoulder height is M10, (M10-M9 ) / M90 toner according to claim 1 or 2 wherein the 0.1-7. The toner according to claim 1, wherein the unsaturated polyvalent carboxylic acid or anhydride thereof contains maleic acid as a component. There are two opposing rolls that rotate in different directions and can be heated or cooled, providing a temperature difference between the roll temperature of one roll (RL1) and the roll temperature of the other roll (RL2), and The toner according to claim 1 or 2 , wherein the roll (RL1) and the roll (RL2) are rotated at different peripheral speeds, and the toner material is kneaded between the two rolls. There are two opposing rolls that rotate in different directions and can be heated or cooled. One roll (RL1) has a temperature difference between the first half and the second half, and the first half of the roll (RL1) A temperature difference is provided between the roll temperature and the roll temperature of the other roll (RL2), and the roll (RL1) and the roll (RL2) are rotated at different peripheral speeds to knead the toner material between the two rolls. The toner according to claim 1 or 2 to be treated. 10. The toner according to claim 8 , wherein the toner is processed so as to satisfy the relationship of (Equation 1), where Rw1 is a peripheral speed of the roll (RL1) and Rw2 is a peripheral speed of the roll (RL2).

10. The process according to claim 8, wherein when the load current value during rotation of the roll (RL1) is Dr1 and the load current value of the roll (RL2) is Dr2, processing is performed so as to satisfy the relationship of (Equation 2). Toner.

The roll temperature of the first half of the roll (RL1) is Trj1, the roll temperature of the second half of the roll (RL1) is Trk1, the softening point (melting temperature in the 1/2 method) of the binder resin is Tm, and the DSC of the fixing aid When the melting point by the method is Tw and the addition amount of the fixing aid is Sw (the blending amount (part by weight) with respect to 100 parts by weight of the binder resin), the processing is performed so as to satisfy the relationship of (Equation 3). The toner according to claim 8 or 9 .

The roll temperature of the first half of the roll (RL1) is Trj1, the roll temperature of the second half of the roll (RL1) is Trk1, the softening point of the binder resin (melting temperature in the 1/2 method) is Tm, and the fixing aid DSC When the melting point by the method is Tw and the addition amount of the fixing aid is Sw (the blending amount (part by weight) with respect to 100 parts by weight of the binder resin), the processing is performed so as to satisfy the relationship of (Equation 4). The toner according to claim 8 or 9 .

A transfer material is inserted between the image carrier and the conductive elastic roller, and a transfer bias voltage is applied to the conductive elastic roller to visualize the electrostatic latent image on the image carrier. An electrophotographic apparatus comprising toner transfer means for transferring, wherein the toner according to claim 1 is used. Toner is supplied to the developing roller by a supply roller made of urethane resin that is supported rotatably and abuts against the developing roller. the on the developing roll is brought into contact with a doctor blade to form a layer of toner, the developing roller and contacting the image bearing member comprises a contact type non-magnetic one-component unit that develops, claims 1 to 13, wherein An electrophotographic apparatus using the toner. When developing with contact development of toner by applying a DC or AC bias, an AC bias having a frequency of 0.5 to 10 kHz and a bias of 0.3 to 1.2 kV (pp) is applied, and the photosensitive member and the developing roller The electrophotographic apparatus according to claim 15 , wherein the peripheral speed ratio is 1: 1.2 to 1: 1.8. A toner image in which an electrostatic latent image formed on an image carrier is visualized is brought into contact with the surface of an endless intermediate transfer member on the image carrier, and the toner image is placed on the surface of the intermediate transfer member. The primary transfer process to be transferred is repeatedly performed a plurality of times, and then the secondary transfer is performed to collectively transfer the overlapping transfer toner image formed on the surface of the intermediate transfer body onto the transfer material by the repeated execution of the primary transfer process a plurality of times. An electrophotographic apparatus comprising a transfer system configured to perform a process and using the toner according to claim 1 . A cleaning process step of transferring a toner image in which an electrostatic latent image formed on the image carrier is visualized to a transfer material by a transfer unit, and recovering toner remaining on the image carrier after the transfer process by cleaning; without having the next charging, exposure, the cleanerless process of performing development process as a basic configuration, an electrophotographic apparatus, characterized by the use of toner of claim 1 to 13 wherein. A plurality of movable image forming units each including at least a rotating image carrier and developing means having toners of different colors, and forming toner images of different colors on the image carrier; An image forming position constituted by a single exposure position and a single transfer position, an image forming unit group in which the plurality of image forming units are arranged in an annular shape, and each of the plurality of image forming units are each A moving means for rotating and moving the entire image forming unit group to sequentially move to one image forming position; an exposing means for generating signal light; and the exposing means at a rotation center of the rotational movement of the image forming unit group. DOO of and a mirror for guiding the exposure position light, comprising a color image forming system for transferring superimposed by aligning the toner images of different colors on the transfer material, according to claim 1 to 13, wherein Electrophotographic apparatus, characterized by the use of over. A heat-resistant belt having a heat resistance and a deformability and having a surface layer made of any one of silicone rubber, fluororubber and fluororesin, a fixing roller, a pressure roller, and a heating member. An electrophotographic apparatus comprising a fixing system for fixing by the action of pressure, wherein the toner according to claim 1 is used.

Images