JP3792923B2 - Color toner and image forming method - Google Patents

Description

〔式中、Ｒはアルコキシ基を示し、ｍは１〜３の整数を示し、Ｙはアルキル基，ビニル基，グリシドキシ基又はメタクリル基の如き炭化水素基を示し、ｎは１〜３の整数を示す〕
【００５９】
より好ましくは、
【００６０】
【外２】

〔式中、ａは４〜１２の整数を示し、ｂは１〜３の整数を示す〕で示されるアルキルアルコキシシラン化合物が良い。
【００６１】
一般式におけるａが４より小さいと、処理は容易となるが良好な疎水性が得られにくい。また、ａが１３より大きいと疎水性は十分になるが、微粉体同士の合一が多くなり流動性付与能が低下してしまう傾向を示す。また、ｂは３より大きいと反応性が低下して良好な疎水化が得られにくい。従って本発明において、ａは好ましくは４〜１２、より好ましくは４〜８であり、ｂは好ましくは１〜３、より好ましくは１〜２が良い。
【００６２】
例えばビニルトリメトキシシラン、ビニルトリエトキシシラン、γ−メタクリルオキシプロピルトリメトキシシラン、ビニルトリアセトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、イソブチルトリメトキシシラン、ジメチルジメトキシシラン、ジメチルジエトキシシラン、トリメチルメトキシシラン、ヒドロキシプロピルトリメトキキシラン、フェニルトリメトキシシラン、ｎ−ヘキサデシルトリメトキシシラン、ｎ−ヘキサデシルトリメトキシシラン、ｎ−オクタデシルトリメトキシシラン等を挙げることができる。
【００６３】
シランカップリング剤の処理量は、アルミナ微粉体１００重量部に対して１〜５０重量部、好ましくは３〜４５重量部である。疎水性アルミナ微粉体は疎水化度が３０〜９０％、より好ましくは４０〜８０％が良い。
【００６４】
疎水化度は３０％より小さいと、高湿下での長期放置による帯電量が低下し、装置本体側での帯電促進の機構が必要となり、装置が複雑化する。また、シリコーンオイルの吸収性が低下し、定着画像表面にオイルムラが発生しやすい。一方、疎水化度が９０％を超えると、アルミナ微粉体自身の帯電コントロールが難しくなり、結果として低湿下でトナーがチャージアップしやすい。
【００６５】
さらに処理アルミナ微粉体は、カラートナーの流動性付与の点から長さ平均粒径は、好ましくは０．００５〜０．１μｍ、より好ましくは０．００５〜０．０５μｍが良い。
【００６６】
長さ平均粒径が０．１μｍより大きいと、流動性が低下し、カラートナーの帯電が不均一となりやすく、結果として、トナー飛散やカブリが生じやすく、高画質な画像を生成しにくくなる。また、平均粒径が０．００５μｍより小さいと、カラートナー粒子表面に疎水性アルミナ微粉体が埋め込まれやすくなり、カラートナーの劣化が生じやすく、耐久性が低下しやすい。この傾向はシャープメルト性のカラートナー粒子に適用した場合、より顕著である。０．００５μｍより小さいと、アルミナ粒子の活性が高く、アルミナ粒子同士が凝集しやすくなり、目的とする高流動性が得られにくい。本発明における疎水性アルミナ微粉体の粒径は、透過型電子顕微鏡により０．００１μｍ以上のアルミナ粒子を測定する。
【００６７】
さらに本発明においては、疎水性アルミナ微粉体はＢＥＴ比表面積が１３０ｍ² ／ｇ以上より好ましくは、１５０〜４００ｍ² ／ｇであることが好ましい。
【００６８】
ＢＥＴ比表面積が１３０ｍ² ／ｇより小さいと、アルミナ粒子が成長した、もしくはα型の結晶構造を有するアルミナまで結晶変化したアルミナが一部混在しており、これでは目的とする高流動性が得られにくい。また、処理前の未処理の段階では非常に高いＢＥＴ値を示していたにも拘わらず、処理の工程で大きくＢＥＴ値も低下しやすい。結果的にＢＥＴ比表面積が１３０ｍ² ／ｇより小さくなってしまったものは、アルミナ粒子が溶液中で均一に分散されず凝集体になったまま処理剤と反応してしまったケースや、もしくは処理剤自体が自己縮合し、一部オイル状となってアルミナ粒子または凝集体表面に付着してしまったケースであり、好ましくはない。
【００６９】
アルミナ微粉体の処理方法は、溶液中でアルミナ微粉体を機械的に一次粒径となるように分散しながら、カップリング剤を加水分解させて処理する方法が効果的である。
【００７０】
本発明に好適なシランカップリング剤で処理された疎水性アルミナ微粉体の添加量は、トナー粒子１００重量部に対して０．５〜５重量部、好ましくは０．６〜３重量部、より好ましくは０．７〜２．５重量部である。
【００７１】
０．５重量部より少ないと、トナー粒子への流動性付与性が低く、また逆に５重量部より多い場合にはトナーから離脱した処理アルミナ微粉体が、キャリア表面を汚染してキャリア自身の帯電付与能を低下させるので好ましくない。また遊離した処理アルミナ微粉体は現像時に感光体表面上に飛びやすく、クリーニング不良の原因にもなりやすい。さらにカラートナー用として用いる場合、処理アルミナ微粉体が多く含有されていると、ＯＨＰの投影像にかげりが生じやすく、鮮明なものが得られにくい。
【００７２】
本発明のカラートナーにおいて、カラートナー粒子の結着樹脂としてトリメリット酸の如き架橋剤で架橋されているポリエステル樹脂が使用される。ポリエステル樹脂の架橋は、カラートナー温度１３０℃における貯蔵弾性率（Ｇ′₁₃₀ ）が２×１０³ 〜２×１０⁴ 〔ｄｙｎ／ｃｍ² 〕であり、温度１７０℃における貯蔵弾性率（Ｇ′₁₇₀ ）が５×１０³ 〜５×１０⁴ 〔ｄｙｎ／ｃｍ² 〕であり、Ｇ′₁₇₀ ／Ｇ′₁₃₀ の値が０．２５〜１０となるようにする必要がある。ポリエステル樹脂の架橋は、トリメリット酸の如き架橋剤での架橋に加えて、トナー粒子の製造段階で有機金属化合物により架橋構造が形成されることがより好ましい。カラートナーが、上記粘弾性特性を満足していると、色調の異なるカラートナーとの混色性が良好であり、耐オフセット性にも優れ、両面定着時においても、定着画像の損傷や、ローラへの巻き付きの発生が抑制される。
【００７３】
ポリエステル樹脂を生成するための二価のアルコール成分としてはエチレングリコール、プロピレングリコール、１，３−ブタンジオール、１，４−ブタンジオール、２，３−ブタンジオール、ジエチレングリコール、トリエチレングリコール、１，５−ペンタンジオール、１，６−ヘキサンジオール、ネオペンチルグリコール、２−エチル−１，３−ヘキサンジオール、水酸化ビスフェノールＡ、また式Ａで表わされるビスフェノール誘導体
【００７４】
【外３】

〔式中、Ｒはエチレン、プロピレン基であり、ｘ，ｙはそれぞれ１以上の整数であり、かつｘ＋ｙの平均値は２〜１０である。〕が挙げられる。
【００７５】
非線形状の架橋ポリエステル樹脂を形成するための架橋剤として機能する三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−トリヒドロキシベンゼンが挙げられる。三価以上の多価アルコールの使用量は、全モノマー基準で、０．１〜１．９ｍｏｌ％が好ましい。
【００７６】
また、ポリエステル樹脂を生成するための二価の酸成分としては、フマル酸，マレイン酸，無水マレイン酸，コハク酸，アジピン酸，セバチン酸，マロン酸およびこれらを炭素数８〜２２の飽和もしくは不飽和の炭化水素基で置換した脂肪族系酸成分モノマー；また芳香族系酸成分モノマーとして、フタル酸，イソフタル酸，無水フタル酸，テレフタル酸およびそのエステル誘導体があげられる。
【００７７】
非線形状の架橋ポリエステル樹脂を形成するための架橋剤として機能する三価以上の多価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−ナフタレントリカルボン酸、２，５，７−ナフタレントリカルボン酸、１，２，４，５−ベンゼンテトラカルボン酸および、これらの無水物やエステル化合物があげられる。三価以上の多価カルボン酸成分の使用量は、全モノマー基準で０．１〜１．９ｍｏｌ％が好ましい。
【００７８】
ポリエステル樹脂の好ましいガラス転移温度は５０〜８０℃、さらに好ましくは５１〜７５℃である。ポリエステル樹脂のＴＨＦ可溶分のＧＰＣ測定において、数平均分子量（Ｍｎ）が１０００〜９０００であることが好ましく、より好ましくは１５００〜７５００である。メインピークの分子量（Ｍｐ）は５０００〜１２０００であることが好ましく、より好ましくは５５００〜１１０００である。ポリエステル樹脂のＴＨＦ可溶分の重量平均分子量（Ｍｗ）とＭｎとの比（Ｍｗ／Ｍｎ）は５．０以下であることが好ましい。
【００７９】
特に、ポリエステル樹脂は、３価以上の多価カルボン酸成分又は３価以上の多価アルコール成分で非線状化されており、後述する測定方法によるクロロホルム不溶分の含有量がポリエステル樹脂の重量を基準として０〜１重量％（より好ましくは、０〜０．９重量％、さらに好ましくは０〜０．５重量％）であることが好ましい。
【００８０】
ＴＨＦ不溶分が１重量％以下であり、非線状構造を有するポリエステル樹脂は、第１段階として二価のカルボン酸成分又は２価のカルボン酸エステル成分と、二価のアルコール成分とを縮重合させて線状のプレポリマーを生成し、第２段階として線状のプレポリマーと二価のカルボン酸成分（又は、そのエステル）と、ポリエステル樹脂を生成するための二価の酸成分としては、フマル酸，マレイン酸，無水マレイン酸，コハク酸，アジピン酸，セバチン酸，マロン酸およびこれらを炭素数８〜２２の飽和もしくは不飽和の炭化水素基で置換した脂肪族系酸成分モノマー；または芳香族系酸成分モノマーとして、フタル酸，イソフタル酸，無水フタル酸，テレフタル酸およびそのエステル誘導体があげられる。
【００８１】
非線形状の架橋ポリエステル樹脂を形成するための三価以上の多価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−ナフタレントリカルボン酸、２，５，７−ナフタレントリカルボン酸、１，２，４，５−ベンゼンテトラカルボン酸および、これらの無水物やエステル化合物があげられる。三価以上の多価カルボン酸成分の使用量は、全モノマー基準で０．１〜１．９ｍｏｌ％が好ましい。
【００８２】
ポリエステル樹脂の好ましいガラス転移温度は５０〜８０℃、さらに好ましくは５１〜７５℃である。ポリエステル樹脂のＴＨＦ可溶分のＧＰＣ測定において、数平均分子量（Ｍｎ）が１０００〜９０００であることが好ましく、より好ましくは１５００〜７５００である。メインピークの分子量（Ｍｐ）は５０００〜１２０００であることが好ましく、より好ましくは５５００〜１１０００である。ポリエステル樹脂のＴＨＦ可溶分の重量平均分子量（Ｍｗ）とＭｎとの比（Ｍｗ／Ｍｎ）は５．０以下であることが好ましい。
【００８３】
特に、ポリエステル樹脂は、３価以上の多価カルボン酸成分又は３価以上の多価アルコール成分で非線状化されており、ＴＨＦ不溶分の含有量がポリエステル樹脂の重量を基準として１重量％以下であることが好ましい。
【００８４】
ＴＨＦ不溶分が１重量％以下であり、非線状構造を有する架橋ポリエステル樹脂は、第１段階として二価のカルボン酸成分又は２価のカルボン酸エステル成分と、二価のアルコール成分とを縮重合させて線状のプレポリマーを生成し、第２段階として線状のプレポリマーと二価のカルボン酸成分（又は、そのエステル）と、二価のアルコール成分と、三価以上の多価カルボン酸成分（又は、そのエステル酸無水物）又は三価以上の多価アルコール成分とを縮重合させて生成するのが好ましい。
【００８５】
ポリエステル樹脂は、酸価が１〜３０ｍｇＫＯＨ／ｇ（より好ましくは、３乃至２５ｍｇＫＯＨ／ｇ）であることが摩擦帯電特性の安定化及び各環境下での電子写真特定の安定化の点で好ましい。
【００８６】
特に、好ましいポリエステル樹脂としては、下記式（Ｂ）
【００８７】
【外４】

〔式中、ｘ及びｙは、１以上の整数であり、ｘ＋ｙの平均値は２〜４である〕で示される分子骨格を有するポリエステル樹脂が好ましい。
【００８８】
式（Ｂ）で示される分子骨格を有するポリエステル樹脂は、多価カルボン酸成分又は多価アルコール成分で非線状構造を形成されていることがより好ましい。
【００８９】
式（Ｂ）で示される分子骨格を有するポリエステル樹脂は、有機金属化合物により加熱時に、金属イオン架橋構造が形成されやすく、トナーの貯蔵弾性率曲線を良好に調整し得る。
【００９０】
式（Ｂ）で示される分子骨格がポリエステル樹脂中に存在すると有機金属化合物との親和性に優れ、この親和性がさらに式（Ｂ）で示される分子骨格中の
【００９１】
【外５】

のπ電子と酸素原子が有機金属化合物に含有される金属に電子供与するようになり、ある種の配位性を有するようになる。この作用は特に金属原子がアルミニウムの場合に顕著である。これは、アルミニウム原子は有機金属化合物内に結合を３つ形成すると、アルミニウム原子は電子のオクテット（８個の電子による４組の電子対の形成）から電子が２個欠けた状態となる。そのため、アルミニウムの有機金属化合物はさらに２個の電子を受け取ることで電子を８個に増やす傾向にあるためと考えられる。アルミニウムの如き金属原子または２価以上の金属原子と式（Ｂ）で示される分子骨格とで形成され、これが従来の結着樹脂の側鎖又は末端カルボキシル基との強固な金属イオン架橋とは異なる化学的親和力による分子間の絡み合いが形成される。これが従来にない低温定着性と耐高温オフセット性とを両立するとともに、ポリエステル樹脂と有機酸金属化合物との新たなる相互作用効果で次の作用効果（１）〜（５）、特に定着性改良とともに転写効率が著しく向上すると解される。
【００９２】
（１）定着開始温度を上昇させることなく、耐オフセット性が向上する。しかも高温（４５℃）状態での長時間放置においてもトナー凝集することなく、放置前と同じ状態で現像性の変動も少ない。
【００９３】
（２）転写性が極めて良好で、ハーフトーン（中間色）現像を転写紙（または転写材）上に忠実に再現でき、また転写残トナーが少なくなるために静電荷像担持体の表面体クリーニングにおけるトナー付着やクリーニング時に生じる傷の発生をおさえることができる。
【００９４】
（３）カラートナーの流動性が極めて良好で、低温／低湿，高温／高湿下などの各環境下においても安定した良好な帯電性（現像性）を維持し、カブリの発生，画像形成装置内でのトナー飛散が抑制される。
【００９５】
（４）現像スリーブ及びキャリア粒子の如き帯電付与部材への汚染が少なく、長期間の使用においても現像性が初期と同等の良好な画像形成ができる。
【００９６】
（５）カラートナーの製造時において着色剤のポリエステル樹脂への分散性が良好で少ない着色剤の添加で十分な画像濃度を達成することができる。着色剤の分散性が良好であるとトナー製造時、微粉砕後の分級工程の分級微粉の再利用化を容易なものとする。
【００９７】
さらに好ましいポリエステル樹脂は、式（Ｂ）で示される分子骨格が２個以上連結している式−Ｃ−Ｄ−Ｃ−Ｄ−
〔式中、Ｃは、
【００９８】
【外６】

（式中、ｘ及びｙは１以上の整数を示す）を示し、
【００９９】
【外７】

で示される分子骨格を有し、三価以上の多価カルボン酸又は多価アルコールで非線状化されているポリエステル樹脂である。
【０１００】
その様な式−Ｃ−Ｄ−Ｃ−Ｄで示される分子骨格を有し、非線形構造を有するポリエステル樹脂は、下記式（Ｅ）
【０１０１】
【外８】

（式中、ｘ，ｙは１以上の整数でｘ＋ｙの平均値は２〜４である。）で示されるビスフェノール誘導体とフマル酸とを縮重合させてプレポリマーを生成し、該プレポリマーと、ジオールと、ジカルボン酸と、３価以上の多価カルボン酸又は３価以上の多価アルコールとを縮重合させることにより生成することができる。
【０１０２】
式（Ｂ）で示される分子骨格がなぜ特異的に有機金属化合物と作用するかは十分には判明していないが、この分子鎖特有の屈曲性が相互作用しやすい配座を形成しやすいため（分子配置相互作用）と、Ｐ位に電子供与性を有するフェニル基の電子供与性、また−ＣＨ＝ＣＨ−のπ電子供与性相互作用が係わっていると思われる。
【０１０３】
一方、ビスフェノール誘導体が下記式（Ｆ）
【０１０４】
【外９】

で示す如く、プロポキシ基を有する場合は、メチル基が存在するので、その立体障害のためか上述のような顕著な作用効果は見い出せない。
【０１０５】
また、下記式（Ｇ）
【０１０６】
【外１０】

で示される、エチレングリコールとテレフタル酸とから形成された分子骨格でも顕著な作用効果は見い出せなく、さらに、下記式（Ｈ）
【０１０７】
【外１１】

で示される、エチレングリコールとフマルル酸とから形成され分子骨格でも顕著な作用効果は見い出せないものである。
【０１０８】
本発明のカラートナーにおいて、カラートナー粒子のクロロホルム不溶分が０〜２０ｍｇ／ｇである。カラートナー粒子のクロロホルム不溶分とは、下記測定方法で測定した値である。
【０１０９】
カラートナー粒子のクロロホルム不溶分の測定方法
カラートナー粒子に外添剤が外添されている場合は、カラートナー粒子から外添剤を除いた後にクロロホルム不溶分を測定する。または、あらかじめカラートナー粒子に外添されている外添剤のクロロホルム不溶分を測定しておき、外添剤が外添されているカラートナーのクロロホルム不溶分を測定後に、外添剤に基因するクロロホルム不溶分量を差し引いた値をカラートナー粒子のクロロホルム不溶分量とする。
【０１１０】
カラートナー粒子１ｇを室温にて５０ｍｌのクロロホルムに添加し撹拌後、超音波による分散を５分間おこなう。得られたクロロホルム溶液をメンブランフィルター（重量Ｗ₁ ｇ）によりクロロホルム不溶分を濾別する。クロロホルム不溶分を担持しているメンブランフィルターを乾燥してクロロホルムを除去した後にクロロホルム不溶分を担持しているメンブランフィルターの重量（Ｗ₂ ｇ）を測定し、カラートナー粒子１ｇ当りのクロロホルム不溶分の重量を算出する。
【０１１１】
クロロホルム不溶分の重量（ｍｇ／１ｇ）＝Ｗ₂ −Ｗ₁
重量Ｗ₁ 及びＷ₂ は０．１ｍｇの位まで測定する。メンブランフィルターとしては、住友電気工業（株）のフルオロポアメンブランフィルター（Ｔｙｐｅ ＦＰ−１００；ポアサイズ１０．００μｍ；直径４７ｍｍ）が挙げられる。
【０１１２】
カラートナー粒子の１ｇ当りのクロロホルム不溶分が０〜２０ｍｇ／１ｇであるということは、粒径の粗い着色剤が少なく着色剤が架橋されているポリエステル樹脂に微細に分散されていることを意味し、さらに、カラートナー粒子を構成している架橋されているポリエステル樹脂にクロロホルムに不溶な分子量の極めて大きい樹脂成分が少ないことを意味している。
【０１１３】
カラートナー粒子のクロロホルム不溶分が０〜２０ｍｇ／１ｇ（より好ましくは、０〜１５ｍｇ／１ｇ）であり、カラートナーの温度１３０℃における貯蔵弾性率が２×１０³ 〜２×１０⁴ 〔ｄｙｎ／ｃｍ〕であり、温度１７０℃における貯蔵弾性率（Ｇ′₁₇₀ ）が５×１０³ 〜５×１０⁴ 〔ｄｙｎ／ｃｍ² 〕であり、Ｇ′₁₇₀ ／Ｇ′₁₃₀ の値が０．２５〜１０（より好ましくは０．５〜１０、さらに好ましくは１〜１０）であると、オーバーヘッドプロジェクターに使用されるＯＨＰフィルムのカラー定着画像、マルチカラー定着画像及びフルカラー定着画像の光透過性に優れ、加熱加圧定着時のカラートナー同志の混色性に優れ、定着性に優れ、耐オフセット性に優れ、定着性と耐オフセット性のバランスも良好であり、さらに、転写材の両面に加熱加圧定着によりフルカラー画像を形成しても表面及び裏面のグロス着が少なく、画質の差が少なく、加熱加圧定着工程を二回受ける表面の定着画像の損傷の発生が抑制される。
【０１１４】
カラートナーの着色剤としては、公知の染料または／及び顔料が使用される。
【０１１５】
マゼンタトナー用着色顔料としてはＣ．Ｉ．ピグメントレッド１，２，３，４，５，６，７，８，９，１０，１１，１２，１３，１４，１５，１６，１７，１８，１９，２１，２２，２３，３０，３１，３２，３７，３８，３９，４０，４１，４８，４９，５０，５１，５２，５３，５４，５５，５７，５８，６０，６３，６４，６８，８１，８３，８７，８８，８９，９０，１１２，１１４，１２２，１２３，１６３，２０２，２０６，２０７．２０９；Ｃ．Ｉ．ピグメントバイオレット１９；Ｃ．Ｉ．バットレッド１，２，１０，１３，１５，２３，２９，３５などが挙げられる。
【０１１６】
顔料単独使用でもかまわないが、染料と顔料と併用してその鮮明度を向上させた方がフルカラー画像の画質の点からより好ましい。
【０１１７】
マゼンタトナー用染料としては、Ｃ．Ｉソルベントレッド１，３，８，２３，２４，２５，２７，３０，４９，８１，８２，８３，８４，１００，１０９，１２１；Ｃ．Ｉ．ディスパースレッド９；Ｃ．Ｉ．ソルベントバイオレット８，１３，１４，２１，２７；Ｃ．Ｉ．ディスパーバイオレット１の如き油溶染料、Ｃ．Ｉ．ベーシックレッド１，２，９，１２，１３，１４，１５，１７，１８，２２，２３，２４，２７，２９，３２，３４，３５，３６，３７，３８，３９，４０；Ｃ．Ｉ．ベーシックバイオレット１，３，７，１０，１４，１５，２１，２５，２６，２７，２８などの塩基性染料が挙げられる。
【０１１８】
シアントナー用着色顔料としては、Ｃ．Ｉ．ピグメントブルー２，３，１５，１６，１７；Ｃ．Ｉ．バットブルー６；Ｃ．Ｉ．アシッドブルー４５または下記式で示される構造を有するフタロシアニン骨格にフタルイミドメチル基を１〜５個置換した銅フタロシアニン顔料などが挙げられる。
【０１１９】
【外１２】

〔式中、ｎは１〜５の整数を示す〕
【０１２０】
イエロー用着色顔料としてはＣ．Ｉ．ピグメントイエロー１，２，３，４，５，６，７，１０，１１，１２，１３，１４，１５，１６，１７，２３，６５，７３，８３，９７，１８０；Ｃ．Ｉ．バットイエロー１，３，２０などが挙げられる。
【０１２１】
着色剤の使用量は、結着樹脂１００重量部に対して好ましくは０．１〜１５重量部、より好ましくは０．５〜１２重量部、最も好ましくは３〜１０重量部が良い。
【０１２２】
本発明に使用するカラートナー粒子を作製するにはポリエステル樹脂及び着色剤としての顔料又は染料、必要に応じて荷電制御剤、その他の添加剤等をボールミルの如き混合機により充分混合してから加熱ロール、ニーダー、エクストルーダーの如き熱混練機を用いて溶融、捏和及び練肉して樹脂類を互いに相溶せしめた中に顔料又は染料を分散又は溶解せしめ、冷却固化後粉砕及び厳密な分級を行ってカラートナー粒子を得ることができる。
【０１２３】
未定着トナー量（Ｍ／Ｓ）をＭ／Ｓ＝０．５ｍｇ／ｃｍ² とした時の通常一回定着後の画像濃度（Ｄ_0.5 ）が、１．２以上、１．８以下となる着色力を有するカラートナーを得るためには、下記の如き顔料分散方法が好ましい。
【０１２４】
カラートナー粒子中の顔料粒子の分散状態を向上させるには、第１のポリエステル樹脂と、分散媒に対して不溶性の顔料粒子５〜５０重量％を含有するペースト顔料とを、混練機または混合機に仕込み、非加圧下で混合しながら加熱して第１のポリエステル樹脂を溶融させ、ペースト顔料（すなわち液相中の顔料）を、加熱されている第１のポリエステル樹脂の溶融樹脂相に移行させた後、第１のポリエステル樹脂及び顔料粒子を溶融混練し、液体分を除去蒸発させて乾燥し、第１のポリエステル樹脂及び顔料粒子を有する第１の混練物を得、次いで第１の混練物に第２のポリエステル樹脂、さらに必要に応じて電荷制御剤の如き添加物等を加えた混合物を、加熱溶融混練して第２の混練物を得、得られた第２の混練物を冷却後粉砕及び分級してトナー化することが好ましい。ここで、第１のポリエステル樹脂と第２のポリエステル樹脂は、同じであっても異なるポリエステル樹脂であっても構わない。
【０１２５】
上記ペースト顔料とは、顔料粒子製造工程において該顔料粒子がただの一度も乾燥工程を経ずに存在している状態を指す。換言すれば、顔料粒子がほぼ一次粒子の状態で全ペースト顔料に対して５〜５０重量％存在している状態である。ペースト顔料中の残りの５９〜９５重量％は若干の分散剤及び助剤などと共に大部分の揮発性の液体が占めている。該揮発性の液体は、一般の加熱によって蒸発する液体であれば特に何ら限定するものではないが、本発明において特に好ましく用いられ、エコロジー的にも好ましく用いられる液体は水である。
【０１２６】
不溶性の顔料粒子とは、ペースト顔料中の揮発性の液体である分散媒に不溶の顔料粒子であり、ペースト顔料中に分散しうるものである。例えば揮発性液体に水を選択した場合は、水に不溶の顔料粒子は全て不溶性の顔料粒子である。
【０１２７】
ペースト顔料は、水不溶性の顔料粒子を５〜５０重量％、より好ましくは５〜４５重量％含有していることが良い。不溶性顔料の含有量が５０重量％を超える場合には、ポリエステル樹脂への分散効率が低く、混練温度を高く、もしくは混練時間を長く設定しなくてはならない。さらには混練装置に強力なスクリューやバトル構成が必須となり、高分子鎖切断を引き起こし易くなる。
【０１２８】
逆にペースト顔料が固形分で５重量％より少ない不溶性顔料を含有している時は、目的とする顔料コンテントを得るためには、ペースト顔料を混合装置に多量に投入せざるを得ず、混合装置が大型化するので好ましくない。さらに、５重量％未満では、第一の混練時以後の工程での水除去の工程を強化して、水を完全に飛ばさなくてはならなくなり、結果的にポリエステル樹脂に大きな負荷を与えてしまうことになる。
【０１２９】
ペースト顔料とポリエステル樹脂とを混練もしくは混合する際は、固形分換算での顔料とポリエステル樹脂との割合が１０：９０〜５０：５０、好ましくは１５：８５〜４５：５５が良い。
【０１３０】
ポリエステル樹脂に対する顔料の割合が１０重量％より小さい時は、ペースト顔料に対して多量のポリエステル樹脂を混練機に仕込まねばならず、混練物中で顔料の偏析が起こり易く、これを均一にするためには、混練時間を長く設定せざるを得ない。この場合、ポリエステル樹脂に余計な負荷をかけてしまい、ポリエステル樹脂の特性が変化してしまうおそれがある。
【０１３１】
ポリエステル樹脂に対する顔料の割合が５０重量％より多い時は、液相中の顔料粒子のポリエステル樹脂への移行がスムーズに行なわれにくく、加えて、顔料粒子の移行後の溶融混練時においても、混練物は均一な溶融状態を示しにくく結果的に良好な分散性が得られにくい。
【０１３２】
非加圧下で溶融混練することが好ましく、その理由は、加圧下ではペースト顔料中の液体（たとえば水）が、ポリエステル樹脂を攻撃し、加水分解反応を一部引き起こしたり、あるいはポリエステル樹脂の変質を引き起こす可能性もあり、耐オフセット性が低下する場合もある。よって本発明においては、非加圧下で第１のポリエステル樹脂とペースト顔料との溶融混練を行なうことが好ましい。
【０１３３】
混練装置としては、加熱ニーダー，一軸押し出し機，二軸押し出し機，ニーダーなどが挙げられ、特に好ましくは加熱ニーダーが挙げられる。
【０１３４】
荷電制御剤をカラートナー粒子中に含有させる場合、荷電制御剤の含有量として結着樹脂１００重量部当り３重量部〜１０重量％、好ましくは４重量部〜８重量部の範囲が好適ではある。
【０１３５】
荷電制御剤を使用すると帯電量の初期変動が少なく、現像時に必要な絶対帯電量が得られやすく、結果的にカブリの発生や画像濃度ダウンが抑制される。
【０１３６】
更に必要に応じて、滑剤としての脂肪酸金属塩（例えばステアリン酸亜鉛、ステアリン酸アルミ等）、フッ素含有量重合体微粉末（例えばポリテトラフルオロエチレン、ポリビニリデンフルオライド等及びテトラフルオロエチレン−ビニリデンフルオライド共重合体の微粉末）或いは、導電性付与剤（酸化スズ、酸化亜鉛）を添加しても良い。
【０１３７】
本発明のカラートナーを二成分系現像剤に用いる場合に、併用されるキャリアとしては、例えば表面酸化又は未酸化の鉄、ニッケル、銅、亜鉛、コバルト、マンガン、クロム、希土類等の金属及びそれらの合金または酸化物及びフェライトなどが使用できる。
【０１３８】
特に、マンガン、マグネシウム及び鉄成分を主成分として形成されるＭｎ−Ｍｇ′−Ｆｅの３元素の磁性フェライト粒子がキャリア粒子として好ましく、さらに、Ｍｎ−Ｍｇ−Ｆｅの３元素の磁性フェライト粒子は、ケイ素元素を０．００１乃至１重量％（より好ましくは、０．００５〜０．５重量％）有していることが磁性フェライト粒子の被覆樹脂としてシリコーン樹脂を使用する場合に特に好ましい。
【０１３９】
磁性キャリア粒子は、樹脂で被覆されていることが好ましく、樹脂としてはシリコーン樹脂が好ましい。特に、含窒素シリコーン樹脂または、含窒素シランカップリング剤とシリコーン樹脂とが反応することにより生成した変性シリコーン樹脂が本発明のカラートナーへのマイナスの摩擦電荷の付与性、環境安定性、キャリアの表面の汚染に対する抑制の点で好ましい。
【０１４０】
磁性キャリアは、平均粒径が１５乃至５０μｍ（より好ましくは、２５乃至４５μｍ）がカラートナーの重量平均粒径との関係で好ましい。
【０１４１】
磁性キャリアの平均粒径及び粒度分布は、レーザー回折式粒度分布測定装置ＨＥＬＯＳ（日本電子製）に乾式分散ユニットＲＯＤＯＳ（日本電子製）を組合わせて用い、レンズ焦点距離２００ｍｍ，分散圧３．０ｂａｒ，測定時間１〜２秒の測定条件で粒径０．５μｍ〜３５０．０μｍの範囲を下記表１に示す通り３１チャンネルに分割して測定し、体積分布の５０％粒径（メジアン径）を平均粒径として求めると共に、体積基準の頻度分布から各粒径範囲の粒子の体積％を求める。
【０１４２】
【表１】

【０１４３】
粒度分布の測定に用いるレーザー回折式粒度分布測定装置ＨＥＬＯＳは、フランホーファ回折原理を用いて測定を行う装置である。この測定原理を簡単に説明すれば、レーザー光源から測定粒子にレーザービームを照射すると、回折像がレーザー光源の反対側のレンズの焦点面にでき、その回折像を検出器によって検出して演算処理することにより、測定粒子の粒度分布を算出するものである。
【０１４４】
磁性粒子を上記の平均粒径及び特定の粒度分布を有するように調製する方法としては、例えば、篩を用いることによる分級によって行うことが可能である。特に、精度良く分級を行うために、適当な目開きの篩を用いて複数回くり返してふるうことが好ましい。また、メッシュの開口の形状をメッキ等によって制御したものを使うことも有効な手段である。
【０１４５】
カラートナーと混合して二成分現像剤を調製する場合、その混合比率は現像剤中のトナー濃度として、２重量％〜１５重量％、好ましくは４重量％〜１３重量％にすると通常良好な結果が得られる。トナー濃度が２％未満では画像濃度が低くなりやすく、１５重量％を超える場合ではカブリや機内飛散が増加しやすい。
【０１４６】
次に、各種物性の測定方法について説明する。
【０１４７】
▲１▼カラートナー又はカラートナー粒子の粒度分布及び平均粒径の測定方法
測定装置としては、コールターカウンターＴＡ−ＩＩ或いはコールターマルチサイザーＩＩ（コールター社製）を用いる。電解液は、１級塩化ナトリウムを用いて、約１％ＮａＣｌ水溶液を調製する。例えば、ＩＳＯＴＯＮ−ＩＩ（コールターサイエンティフィックジャパン社製）が使用できる。測定方法としては、前記電解水溶液１００〜１５０ｍｌ中に分散剤として、界面活性剤（好ましくはアルキルベンゼンスルホン酸塩）を、０．１〜５ｍｌ加え、さらに測定試料を２〜２０ｍｇ加える。試料を懸濁した電解液は、超音波分散器で約１〜３分間分散処理を行い、前記測定装置により、アパーチャーとして１００μｍアパーチャーを用いて、トナー粒子の体積及び個数を各チャンネル毎に測定して、トナーの体積分布と個数分布とを算出する。それから、トナー粒子の体積分布から求めた重量基準のトナーの重量平均粒径（Ｄ４）（各チャンネルの中央値をチャンネル毎の代表値とする）を求める。
【０１４８】
チャンネルとしては、２．００〜２．５２μｍ；２．５２〜３．１７μｍ；３．１７〜４．００μｍ；４．００〜５．０４μｍ；５．０４〜６．３５μｍ；６．３５〜８．００μｍ；８．００〜１０．０８μｍ；１０．０８〜１２．７０μｍ；１２．７０〜１６．００μｍ；１６．００〜２０．２０μｍ；２０．２０〜２５．４０μｍ；２５．４０〜３２．００μｍ；３２．００〜４０．３０μｍの１３チャンネルを用いる。
【０１４９】
▲２▼アルミナ微粉体の長さ平均粒径の測定方法
一次粒子径は、アルミナ微粉体を透過電子顕微鏡で観察し、視野中の０．００１μｍ以上の１００個の粒子径を測定して長さ平均粒子径を求める。トナー粒子上のアルミナ微粉体の分散粒子径は走査電子顕微鏡で観察し視野中の１００個のアルミナ微粉体をＸＭＡにより定性し、その粒子径を測定して平均粒子径を求める。
【０１５０】
▲３▼アルミナ微粉体の疎水化度の測定方法
メタノール滴定試験は、疎水化された表面を有するアルミナ微粉体の疎水化度を確認する実験的試験である。
【０１５１】
処理されたアルミナ微粉体の疎水化度を評価するための“メタノール滴定試験”は次の如く行う。供試アルミナ微粉体０．２ｇを容器中の水５０ｍｌに添加する。メタノールをビュレットからアルミナ微粉体の全量が湿潤されるまで滴定する。この際、容器内の溶液はマグネチックスターラーで常時撹拌する。その終点はアルミナ微粉体の全量が液体中に懸濁されることによって観察され、疎水化度は、終点に達した際のメタノール及び水の液状混合物中のメタノールの百分率として表わされる。
【０１５２】
▲４▼ＢＥＴ比表面積の測定方法
アルミナ微粉体のＢＥＴの実測は次のようにして行う。
【０１５３】
ＢＥＴ比表面積は、湯浅アイオニクス（株）製、全自動ガス吸着量測定装置：オートソーブ１を使用し、吸着ガスに窒素を用い、ＢＥＴ多点法により求める。なお、サンプルの前処理としては、温度５０℃で１０時間の脱気を行う。
【０１５４】
▲５▼結晶構造解析の方法
本発明においてアルミナ微粉体の結晶構造解析は次のようにして行う。
【０１５５】
Ｘ線結晶構造解析は、Ｃｕの特性Ｘ線のＫα線を線源として用いたＸ線回折スペクトルにより求める。測定機としては、例えば強力型全自動Ｘ線回折装置ＭＸｐ¹⁸（マックサイエンス社製）が利用できる。
【０１５６】
アルミナが明確な結晶構造を有する場合、すなわちαタイプのアルミナである場合は、２θ（ｄｅｇ）が２０〜７０にシャープなピークが観測され、γタイプのアルミナである場合は、ブロードなピークがいくつか観測される。一例として、図３と図４に典型的なα型とγ型の回折ピークを示す。
【０１５７】
▲６▼トナーのレオロジー特性の測定
トナーを直径約２５ｍｍ、厚さ約２〜３ｍｍの円板状の試料に加圧成形する。次にパラレルプレートにセットし、５０〜２００℃の温度範囲内で徐々に昇温させ温度分散測定を行う。昇温速度は２℃／ｍｉｎとした。角周波数（ω）は６．２８ｒａｄ／ｓｅｃに固定し、歪率は自動とする。横軸に温度，縦軸に貯蔵弾性率（Ｇ′）を取り、各温度における値を読み取る。測定にあたっては、例えばＲＤＡ−ＩＩ（レオメトリックス社製）を用いる。
【０１５８】
▲７▼ポリエステル樹脂又はカラートナーを構成しているポリエステル樹脂のＧＰＣの測定方法
ポリエステル樹脂のＭｎ、Ｍｗ及びＭｗ／Ｍｎはゲルパーミエーションクロマトグラフィー（ＧＰＣ）によって測定する。４０℃のヒートチャンバ中でカラムを安定化させ、この温度におけるカラムに、溶媒としてテトラハイドロフラン（ＴＨＦ）を毎分１ｍｌの流速で流し、ＴＨＦ試験溶媒を１００μｌ注入して測定する。試料の分子量測定にあたっては、試料の有する分子量分布を、数種の単分散ポリスチレン標準試料により作成された検量線の対数値とカウント数との関係から算出する。検量線作成用の標準ポリスチレン試料としては、例えば、東ソー社製あるいは、昭和電工社製の分子量が１０² 〜１０⁷ 程度のものを用い、少なくとも１０点程度の標準ポリスチレン試料を用いるのが適当である。検出器にはＲ１（屈折率）検出器を用いる。カラムとしては、市販のポリスチレンジェルカラムを複数本組み合わせて使用するのが良い。
【０１５９】
例えば、昭和電工社製のｓｈｏｄｅｘ ＧＰＣ ＫＦ−８０１，８０２，８０３，８０４，８０５，８０６，８０７，８００Ｐの組み合わせや、東ソー社製のＴＳＫｇｅｌＧ１０００Ｈ（Ｈ_XL）、Ｇ２０００Ｈ（Ｈ_XL）、Ｇ３０００Ｈ（Ｈ_XL）、Ｇ４０００Ｈ（Ｈ_XL）、Ｇ５０００Ｈ（Ｈ_XL）、Ｇ６０００Ｈ（Ｈ_XL）、Ｇ７０００Ｈ（Ｈ_XL）、ＴＳＫｇｕａｒｄｃｏｌｕｍｎの組み合わせを挙げることができる。
【０１６０】
試料は例えば、以下の様にして作成する。
【０１６１】
試料をＴＨＦ中に入れ、数時間放置した後、十分振とうしＴＨＦと良く混ぜ（試料の合一体がなくなるまで）、更に１２時間以上静置する。このときＴＨＦ中への放置時間が２４時間以上となるようにする。その後、サンプル処理フィルター（ポアサイズ０．４５〜０．５μｍ、例えばマイショリディスクＨ−２５−５東ソー社製、エキクロディスク２５ＣＲ、ゲルマン、サイエンス ジャパン社製などが使用できる）を通過させたものを、ＧＰＣの試料とする。試料温度は、樹脂成分が０．５〜５ｍｇ／ｍｌとなるように調整する。
【０１６２】
本発明の両面定着工程を有する画像形成方法を実施するための画像形成装置の好ましい一具体例を図１を参照しながら、以下に説明する。
【０１６３】
図１に示す画像形成装置は、下部のデジタルカラー画像プリンタ部（以下単に「プリンタ部」という。）Ｉと、上記のデジタルカラー画像リーダ部（以下単に「リーダ部」という。）ＩＩとを備えており、例えば、リーダ部ＩＩで読み取った原稿Ｄの画像に基づき、プリンタ部Ｉによって記録材Ｐに画像を形成する。
【０１６４】
以下、プリンタ部Ｉの構成、つづいてリーダ部ＩＩの構成を説明する。
【０１６５】
プリンタ部Ｉは、矢印Ｒ１方向に回転駆動される静電荷像担持体としての感光ドラム１を有する。感光ドラム１の周囲には、その回転方向に沿って順に、一次帯電器（帯電手段）２、露光手段３、現像装置（現像手段）４、転写装置５、クリーニング器６、前露光ランプ７等が配置されている。転写装置５の下方（すなわちプリンタ部Ｉの下半部）には、記録材Ｐの給送搬送部８が配置され、さらに転写装置５の上部には分離手段９が設置され、また分離手段９の下流側（記録材Ｐの搬送方向についての下流側）には加熱加圧定着器１０及び排紙部１１が配置されている。
【０１６６】
感光ドラム１は、アルミニウム製のドラム状の基体１ａと、その表面を覆うＯＰＣ（有機光半導体）の感光体１ｂとを有し、駆動手段（不図示）によって矢印Ｒ１方向に所定のプロセススピード（周速度）で回転駆動されるように構成されている。
【０１６７】
一次帯電器２は、感光ドラム１に対向する部分が開口したシールド２ａと、シールド２ａの内側に感光ドラム１の母線と平行に配置された放電ワイヤ２ｂと、シールド２ａの開口部に配置されて帯電電位を規制するグリッド２ｃとを有するコロナ帯電器である。一次帯電器２は、電源（不図示）によって帯電バイアスが印加され、これにより、感光ドラム１表面を所定の極性、所定の電位に均一に帯電するようになっている。
【０１６８】
露光手段３は、後述のリーダ部ＩＩからの画像信号に基づいてレーザ光を発光するレーザ出力部（不図示）と、レーザ光を反射するポリゴンミラー３ａと、レンズ３ｂと、ミラー３ｃとを有する。露光手段３は、このレーザ光が感光ドラム１表面を照射するすることによって感光ドラム１を露光し、露光部分の電荷を除去して静電潜像を形成するように構成されている。本実施例では、感光ドラム１表面に形成される静電潜像は、原稿の画像に基づいて、イエロー、シアン、マゼンタ、ブラックの４色に色分解され、それぞれの色に対応した静電潜像が順次形成されるようになっている。
【０１６９】
現像装置４は、感光ドラム１の回転方向（矢印Ｒ１方向）に沿って上流側から順にイエロートナー、シアントナー、マゼンタトナー、ブラックトナーの各色トナー（現像剤）を収納した現像器４Ｙ、４Ｃ、４Ｍ、４Ｂｋを備えている。各現像器４Ｙ、４Ｃ、４Ｍ、４Ｂｋは、それぞれ感光ドラム１表面に形成された静電荷像を現像するためのトナーを有する現像剤を担持している現像スリーブ４ａを有し、静電荷像の現像に供せられる所定の色の現像器が偏心カム４ｂによって、択一的に感光ドラム１表面に近接する現像位置に配置されている。現像スリーブ４ａに担持されている現像剤のトナーが静電荷像を現像し、顕像としてのトナー像（可視画像）を形成するように構成されている。現像に供せられる現像器以外の他の３色の現像器は、現像位置から退避するようになっている。
【０１７０】
転写装置５は、表面に転写材Ｐを担持する転写ドラム（転写材担持体）５ａ、感光ドラム１上のトナー像を転写材Ｐに転写する転写帯電器（転写帯電手段）５ｂ、転写材Ｐを転写ドラム５ａに吸着させるための吸着帯電器５ｃとこれに対向する吸着ローラ５ｄ、内側帯電器５ｅ、外側帯電器５ｆを有し、矢印Ｒ５方向に回転駆動されるように軸支された転写ドラム５ａの周面開口域には誘電体からなる転写材担持シート５ｇが円筒状に一体的に張設されている。転写材担持シート５ｇは、ポリカーボネートフィルムの如き誘電体シートを使用している。転写装置５は転写ドラム５ａ表面に転写材Ｐを吸着して担持するように構成されている。
【０１７１】
クリーニング器６は、転写材Ｐに転写されずに感光ドラム１表面に残った残留トナーを掻き落とすクリーニングブレード６ａ、及び掻き落したトナーを回収するクリーニング容器６ｂを備えている。
【０１７２】
前露光ランプ７は、一次帯電器２の上流側に隣接して配置され、クリーニング器６によって清掃された感光ドラム１表面の不要な電荷を除去する。
【０１７３】
給紙搬送部８は、大きさの異なる転写材Ｐを積載収納する複数の給紙カセット８ａ、給紙カセット８ａ内の転写材Ｐを給紙する給紙ローラ８ｂ、多数の搬送ローラ、そしてレジストローラ８ｃ等を有し、所定の大きさの転写材Ｐを転写ドラム５ａに供給する。
【０１７４】
分離手段９は、トナー像が転写された後の転写材Ｐを転写ドラム５ａから分離するための分離帯電器９ａ、分離爪９ｂ、そして分離押上げころ９ｃ等を有する。
【０１７５】
加熱加圧定着器１０は、内側にヒータを有する定着ローラ１０ａと、定着ローラ１０ａの下方に配置され、転写材Ｐを定着ローラ１０ａに押し付ける加圧ローラ１０ｂとを有する。
【０１７６】
排紙部１１は、加熱加圧定着器１０の下流側に配置された、搬送パス切替えガイド１１ａ、排出ローラ１１ｂ、排紙トレイ１１ｃ等を有する。また、搬送パス切替えガイド１１ａの下方には、１枚の転写材Ｐに対してその両面に画像形成を行うために搬送縦パス１１ｄ、反転パス１１ｅ、積載部材１１ｆ、中間トレイ１１ｇ、さらに搬送ローラ１１ｈ、１１ｉ、反転ローラ１１ｊ等が配置されている。
【０１７７】
また、感光ドラム１周囲における、一次帯電器２と現像装置４との間には、感光ドラム表面の帯電電位を検出する電位センサＳ₁ が、また現像装置４と転写ドラム５ａとの間には、感光ドラム１上のトナー像の濃度を検知する濃度センサＳ₂ が、それぞれ配置されている。
【０１７８】
つづいて、リーダ部ＩＩについて説明する。プリンタ部Ｉの上方に配置されたリーダ部ＩＩは、原稿Ｄを載置する原稿台ガラス１２ａ、移動しながら原稿Ｄの画像面を露光走査する露光ランプ１２ｂ、原稿Ｄからの反射光をさらに反射させる複数のミラー１２ｃ、反射光を集光するレンズ１２ｄ、そしてレンズ１２ｄからの光に基づいてカラー色分解画像信号を形成するフルカラーセンサ１２ｅ等を有する。カラー色分解画像信号は、増幅回路（不図示）を経て、ビデオ処理ユニット（不図示）によって処理を施され、上述のプリンタ部Ｉに送出されるようになっている。
【０１７９】
次に、上述構成の画像形成装置の動作を説明する。以下の説明においては、イエロー、シアン、マゼンタ、ブラックの順に４色フルカラーの画像を形成するものとする。
【０１８０】
リーダ部ＩＩの原稿台ガラス１２ａに載置された原稿Ｄの画像は、露光ランプ１２ｂによって照射され、色分解されてまずイエローの画像がフルカラーセンサ１２ｅによって読み取られ、所定の処理を施され画像信号としてプリンタ部Ｉに送られる。
【０１８１】
プリンタ部Ｉでは、感光ドラム１が矢印Ｒ１方向に回転駆動され、一次帯電器２によって表面が均一に帯電される。上述のリーダ部ＩＩから送られてきた画像信号に基づいて、露光手段３のレーザ出力部からレーザ光が照射され、ポリゴンミラー３ａ等を介して帯電済の感光ドラム１表面を光像Ｅによって露光する。感光ドラム１表面の露光を受けた部分は、電荷が除去され、これによりイエローに対応した静電荷像が形成される。現像装置４においては、イエローの現像器４Ｙが所定の現像位置に配置され、その他の現像器４Ｃ、４Ｍ、４Ｂｋは現像位置から退避される。感光ドラム１上の静電荷像は、現像器４Ｙによってイエローのトナーが付着され、顕像化されてイエロートナー像となる。この感光ドラム１上のイエロートナー像は、転写ドラム５ａに担持された転写材Ｐに転写される。転写材Ｐは、原稿画像に適した大きさの転写材Ｐが所定の給紙カセットを８ａから給紙ローラ８ｂ、搬送ローラ、そしてレジストローラ８ｃ等を介して所定のタイミングで転写ドラム５ａに供給されたものである。このようにして供給された転写材Ｐは、転写ドラム５ａの表面に巻き付くように吸着されて矢印Ｒ５方向に回転し、転写帯電器５ｂによって感光ドラム１上のイエロートナー像が転写される。
【０１８２】
一方、イエロートナー像が転写された後の感光ドラム１は、クリーニング器６によって表面の残留トナーが除去され、さらに前露光ランプ７によって不要な電荷が除去され、一次帯電から始まる次の画像形成に供される。
【０１８３】
以上のリーダ部ＩＩによる原稿画像の読取りから、転写ドラム５ａ上の転写材Ｐに対するトナー像の転写、さらには感光ドラム１の清掃、除電に至る各プロセスが、イエロー以外の他の色、すなわちシアン、マゼンタ、ブラックについても同様に行われ、転写ドラム５ａ上の転写材Ｐには、イエロートナー，シアントナー，マゼンタトナー及びブラックトナーの４色のトナー像が重なるようにして転写される。
【０１８４】
４色のトナー像の転写を受けた転写材Ｐは、分離帯電器９ａ、分離爪９ｂ等によって転写ドラム５ａから分離され、未定着のトナー像を表面に担持した状態で定着器１０に搬送される。転写材Ｐは、加熱加圧定着器１０の定着ローラ１０ａ及び加圧ローラ１０ｂによって加熱加圧され、カラートナー像が溶融されて定着され、フルカラー画像が転写材の一方の面に形成される。定着後の記録材Ｐは、排出ローラ１１ｂによって排紙トレイ１１ｃ上に排出される。
【０１８５】
次に、図２を参照して加熱加圧定着装置１０について説明する。
【０１８６】
図２において、カラートナー像と接触する定着ローラ１０ａは、例えばアルミニウム製の芯金３１上の１ｍｍ厚のＨＴＶ（高温加硫型）シリコーンゴム層３２、この外側に特定の付加型シリコーンゴム層３３を有し、直径６０ｍｍに形成されている。
【０１８７】
一方、加圧ローラ１０ｂは、例えば、アルミニウム製の芯金３４上に、１ｍｍ厚のＨＴＶと、さらに厚さ１ｍｍの前述の特定の付加型シリコーンゴム層３５を設け、直径６０ｍｍに形成されている。
【０１８８】
上述の定着ローラ１０ａには、発熱手段である搬送ローラヒータ３６が芯金３１内に配設され、加圧ローラ１０ｂには、同じくヒータ３７が芯金３４内に配設されて記録材Ｐの両面からの加熱を行っている。加圧ローラ１０ｂに当接されたサーミスタ３８によって加圧ローラ１０ｂの温度が検知され、この検知温度に基づいて制御装置３９によりハロゲンヒータ３６，３７が制御され、定着ローラ１０ａ及び加圧ローラ１０ｂの温度がともに１７０℃の一定に維持されるように制御される。なお、定着ローラ１０ａと加圧ローラ１０ｂとは、加圧機構（不図示）によって総圧約８０ｋｇで加圧されている。
【０１８９】
また、図２において、Ｏはオイル塗布装置であり、Ｃはクリーニング装置であり、Ｃ１は加圧ローラ１０ｂのオイル汚れを除去するクリーニングブレードである。オイル塗布装置Ｏは、オイルパン４０内のジメチルシリコーンオイル４１をオイル汲み上げローラ５０，４２及びオイル塗布ローラ４３を経由させてオイル塗布量調整ブレード４４でオイル塗布量を規制して定着ローラ１０ａに塗布する。クリーニング装置Ｃは、突当ローラ４５によって定着ローラ１０ａに当接されたウエブ４６によって定着ローラ１０ａ表面を清掃する。
【０１９０】
上述の定着装置１０では、未定着トナー像を表面に担持した転写材Ｐは、定着ローラ１０ａと加圧ローラ１０ｂとの間の定着ニップに挟持搬送され、このとき表裏両面から加熱加圧されてトナーの定着が行われる。この際、定着ローラ１０ａ、加圧ローラ１０ｂに付着したトナーは、それぞれクリーニング装置Ｃ、クリーニングブレードＣ１によって除去される。
【０１９１】
以上、転写材の一方の面のみにフルカラー画像を形成するものについて説明したが、次にこのフルカラー画像を転写材の表面及び裏面の両方に形成する方法及び装置について図１を参照しながら説明する。
【０１９２】
転写材Ｐの両面にフルカラー画像を形成する場合は、加熱加圧定着器１０は排出後の転写材Ｐを、すぐに搬送パス切替えガイド１１ａを駆動し、搬送パス１１ｄを経て、反転パス１１ｅに一旦導いた後、反転ローラ１１ｊの逆転により、送り込まれた際の後端を先頭にして、送り込まれた方向と反対向きに退出させ、中間トレイ１１ｇに収納する。その後、中間トレイ１１ｇの一方の面にフルカラー画像を有する転写材Ｐは転写ドラム５ａに送られ、他方の面に再度上述の画像形成プロセスによりイエロートナー，シアントナー及びマゼンタトナーのカラートナーが転写され、さらにブラックトナーが転写される。転写材Ｐのフルカラー画像が転写ドラム５ａ接触するので、定着時にフルカラー画像面に付着したシリコーンオイルが転写ドラム５ａに付着し、転写工程を通常に阻害しやすいが、本発明のカラートナーは、シリコーンオイルの吸収性に優れているので、転写ドラム５ａに付着するシリコーンオイル量は従来と比較して極めて少ない。
【０１９３】
転写材の他方の面に未定着のカラートナー画像を有する転写材Ｐは、転写ドラム５ａから分離され、加熱加圧定着器１０へ送られ、未定着のカラートナー画像は、転写材の他方の面に加熱加圧定着され、転写材Ｐの両面にフルカラー画像が形成される。その際、本発明のカラートナーは、特定な疎水性アルミナ微粉体がカラートナー粒子に外添され、特定な粒度分布と、特定な粘弾性特性を有しているので、両面が良好におこなえ、定着ローラ１０ａ及び加圧ローラ１０ｂへの転写材Ｐの巻き付きが抑制され、オフセット現象の発生も良好に防止されるものである。
【０１９４】
本発明のカラートナーを使用すると、転写ドラム５ａの転写材担持シート５ｇのシリコーンオイル等の汚染は従来と比較して極めて少ないが、必要によりファーブラシ１３ａとバックアップブラシ１３ｂ及びオイル除去ローラ１４ａとバックアップブラシ１４ｂによって清掃を行う。このような清掃は、必要により画像形成前もしくは画像形成後に行い、またジャム（紙づまり）発生した場合には随時行う。
【０１９５】
【実施例】
疎水性アルミナ微粉体の合成例１
３リットルの２Ｍ重炭酸アンモニウム溶液に、０．２Ｍアンモニウム明バン溶液２リットルを、液温を３５℃に保ちながら１時間に０．８リットルの速度で滴下し、激しく撹拌しながら反応させ、ＮＨ₄ ＡｌＣＯ₃ （ＯＨ）₂ のアルミニウムアンモニウムカーボネートハイドロオキサイド微粉体を生成し、次いで、濾過，乾燥した。得られたアルミニウムアンモニウムカーボネートハイドロオキサイド微粉体はＢＥＴ比表面積２８０ｍ² ／ｇを有していた。該微粉体を約９００℃で２時間加熱処理して、親水性アルミナ微粉体を生成した。生成した親水性アルミナ微粉体は、ＢＥＴ比表面積２５０ｍ² ／ｇを有し、一次粒子の長さ平均粒径は５ｎｍであり、メタノール疎水化度は０％であり、結晶形態はＸ線回折によってγ系であることが確認された。
【０１９６】
次に、トルエン中で上記アルミナ微粉体を均一分散せしめた後、イソブチルトリメトキシシランをアルミナ微粉体１００重量部に対して固型分で３０重量部になる様にアルミナ粒子が合一しないように滴下混合し、加水分解反応せしめた。その後、濾過，乾燥した後、１８０℃で２時間焼き付けし、その後充分に解砕処理して、疎水性アルミナ微粉体Ｎｏ．１を得た。この疎水性アルミナ微粉体Ｎｏ．１の一次粒子の長さ平均粒径は０．００５μｍ（５ｎｍ）であり，ＢＥＴ比表面積は１９０ｍ² ／ｇであり，メタノール疎水化度は６６％であった。
【０１９７】
疎水性アルミナ微粉体の合成例２
γ−アルミナである市販の酸化アルミニウム微粉体（日本アエロジル社製オキサイド−Ｃ，ＢＥＴ比表面積１００ｍ² ／ｇ）を、イソブチルトリメトキシシラン１５重量部を用いて合成例１と同様にして疎水化処理を行って疎水性アルミナ微粉体Ｎｏ．２を得た。物性を表２に示す。
【０１９８】
疎水性アルミナ微粉体の合成例３
有機アルミニウムの加水分解法により生成したγ−アルミナ（ＢＥＴ比表面積１４９ｍ² ／ｇ）を、イソブチルトリメトキシシラン１５重量部を用いて合成例１と同様にして疎水化度処理を行って疎水性アルミナ微粉体Ｎｏ．３を得た。物性を表２に示す。
【０１９９】
疎水性アルミナ微粉体の合成例４
合成例１で使用したＮＨ₄ ＡｌＣＯ₃ （ＯＨ）₂ を、約１２６０℃で約６０分間焼成し、α−アルミナ微粉体を生成した。このアルミナ微粉体はＸ線回折データに鋭い明確なピークを示し、α−タイプであることを確認した。物性を表２に示す。
【０２００】
このα−アルミナ微粉体を用いて合成例１と同じように（但し、処理剤の量は１０重量％に減らして）処理し、疎水性アルミナ微粉体Ｎｏ．４を生成した。物性を表２に示す。
【０２０１】
疎水性シリカ微粉体の合成例
市販の親水性シリカ微粉体（日本アエロジル社製ＡＥＲＯＳＩＲ２００，ＢＥＴ比表面積２００ｍ² ／ｇ）を合成例１と同様にして疎水化処理を行って疎水性シリカ微粉体を得た。物性を表２に示す。
【０２０２】
疎水性酸化チタン微粉体の合成例
チタンアルコキシドを酸化し、生成したアモルファス酸化チタン微粉体（ＢＥＴ比表面積１３５ｍ² ／ｇ）をイソブチルトリメトキシシラン２０重量部を用いて合成例１と同様にして疎水化処理を行い疎水性酸化チタン微粉体を得た。物性を表２に示す。
【０２０３】
【表２】

【０２０４】
ポリエステル樹脂の製造例１
【０２０５】
【外１３】

ｘ＋ｙ＝２．１で表わされるジオール成分（Ｅ−１） ２５ｍｏｌ％
フマル酸（ＨＯＯＣ−ＣＨ＝ＣＨ−ＣＯＯＨ） ２５ｍｏｌ％
【０２０６】
上記モノマーを重縮合させて数平均分子量（Ｍｎ）が８５０の線状プレポリマーを生成した。
【０２０７】
次いで、線状プレポリマーと下記モノマーとを混合して重縮合をおこなって非線状の架橋ポリエステル樹脂（１）を得た。
【０２０８】
【外１４】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ２０ｍｏｌ％
【０２０９】
【外１５】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ５ｍｏｌ％
フマル酸 １０ｍｏｌ％
テレフタル酸 １０ｍｏｌ％
トリメリット酸 ０．２ｍｏｌ％
【０２１０】
得られた架橋ポリエステル樹脂（１）は、ガラス転移温度（Ｔｇ）が５９℃であり、クロロホルム不溶分が０ｗｔ％であり、ＴＨＦ可溶成分のＧＰＣにおいては、数平均分子量（Ｍｎ）が３２００であり、メインピーク（Ｍｐ）が８４００であり、Ｍｗ／Ｍｎが３．６であった。
【０２１１】
ポリエステル樹脂のクロロホルム不溶分とは、下記方法で測定された値である。
【０２１２】
ポリエステル樹脂１ｇを室温にて５０ｍｌのクロロホルムに添加し、撹拌後に超音波による分散を５分間行う。得られたメンブランフィルター（重量Ｗ₁ ｇ）によりクロロホルム不溶分を濾別する。クロロホルム不溶分を担持しているメンブランフィルターを乾燥してクロロホルムを除去した後にクロロホルム不溶分を担持しているメンブランフィルターの重量（Ｗ₂ ｇ）を測定し、クロロホルム不溶分の含有率を下記の如く算出する。
【０２１３】
【外１６】

【０２１４】
ポリエステル樹脂の製造例２
【０２１５】
【外１７】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ２５ｍｏｌ％
フマル酸 ２５ｍｏｌ％
【０２１６】
上記モノマーを重縮合させて数平均分子量（Ｍｎ）が８５０の線状のプレポリマーを生成した。次いで、線状プレポリマーと下記モノマーとを混合して重縮合を行って架橋ポリエステル樹脂（２）を得た。
【０２１７】
【外１８】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 １０ｍｏｌ％
【０２１８】
【外１９】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 １５ｍｏｌ％
フマル酸 １０ｍｏｌ％
テレフタル酸 １５ｍｏｌ％
トリメリット酸 ０．３ｍｏｌ％
【０２１９】
得られた非線状ポリエステル樹脂（２）は、Ｔｇが５６℃であり、クロロホルム不溶分が０ｗｔ％であり、ＴＨＦ可溶成分のＧＰＣにおいて、Ｍｎが３５００であり、Ｍｐが９０００であり、Ｍｗ／Ｍｎが３．９であった。
【０２２０】
ポリエステル樹脂の製造例３
【０２２１】
【外２０】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ３０ｍｏｌ％
フマル酸 ３０ｍｏｌ％
【０２２２】
上記モノマーを重縮合させてＭｎが９２０の線状プレポリマーを得た。次いで、線状プレポリマーと下記モノマーとを混合して重縮合を行って架橋ポリエステル樹脂（３）を得た。
【０２２３】
【外２１】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ２０ｍｏｌ％
フマル酸 １０ｍｏｌ％
テレフタル酸 １０ｍｏｌ％
トリメリット酸 ０．３ｍｏｌ％
【０２２４】
得られた架橋ポリエステル樹脂（３）は、Ｔｇが５４℃であり、クロロホルム不溶分が０ｗｔ％であり、ＴＨＦ可溶成分のＧＰＣにおいて、Ｍｎが３１００であり、Ｍｐが８０００であり、Ｍｗ／Ｍｎが３．５であった。
【０２２５】
ポリエステル樹脂の製造例４
【０２２６】
【外２２】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ２５ｍｏｌ％
【０２２７】
【外２３】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ２５ｍｏｌ％
フマル酸 ５０ｍｏｌ％
テレフタル酸 ０ｍｏｌ％
トリメリット酸 ０．１ｍｏｌ％
【０２２８】
上記モノマーを混合し、重縮合反応を行って、非線状の架橋ポリエステル樹脂（４）を得た。得られた架橋ポリエステル樹脂（４）は、Ｔｇが４９℃であり、クロロホルム不溶分が０ｗｔ％であり、ＴＨＦ可溶成分のＧＰＣにおいて、Ｍｎが２７００であり、Ｍｐが５８００であり、Ｍｗ／Ｍｎが２．８であった。
【０２２９】
ポリエステル樹脂の製造例５
【０２３０】
【外２４】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ３５ｍｏｌ％
【０２３１】
【外２５】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 １５ｍｏｌ％
フマル酸 ３５ｍｏｌ％
テレフタル酸 １５ｍｏｌ％
トリメリット酸 ０．３ｍｏｌ％
【０２３２】
上記モノマーを混合し、縮重合反応を行って、非線状の架橋ポリエステル樹脂（５）を得た。得られた架橋ポリエステル樹脂は、Ｔｇが５８℃であり、クロロホルム不溶分が０ｗｔ％であり、ＴＨＦ可溶成分のＧＰＣにおいて、Ｍｎが３４００であり、Ｍｐが９２００であり、Ｍｗ／Ｍｎが８．０であった。
【０２３３】
ポリエステル樹脂の製造例６
【０２３４】
【外２６】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 １５ｍｏｌ％
【０２３５】
【外２７】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ３５ｍｏｌ％
テレフタル酸 ４８ｍｏｌ％
【０２３６】
上記モノマーを混合し、重縮合反応を行って、線状ポリエステル樹脂（６）を得た。得られた線状ポリエステル樹脂（６）は、Ｔｇが６８℃であり、クロロホルム不溶分が０ｗｔ％であり、ＴＨＦ可溶成分のＧＰＣにおいて、Ｍｎが５８００であり、Ｍｐが１４０００であり、Ｍｗ／Ｍｎが５．２であった。
【０２３７】
ポリエステル樹脂の製造例７
【０２３８】
【外２８】

（ｘ＋ｙ＝２．１）で表わされるジオール成分 ５０ｍｏｌ％
フマル酸 １５ｍｏｌ％
テレフタル酸 ３５ｍｏｌ％
トリメリット酸 ０．６ｍｏｌ％
【０２３９】
上記モノマーを混合し、重縮合を行って非線状の架橋ポリエステル樹脂（７）を得た。得られた架橋ポリエステル樹脂（７）は、Ｔｇが６３℃であり、クロロホルム不溶分が１４．３ｗｔ％であり、ＴＨＦ可溶成分のＧＰＣにおいて、Ｍｎが４８００であり、Ｍｐが１３０００であり、Ｍｗ／Ｍｎが１９．５であった。
【０２４０】
実施例１
・架橋ポリエステル樹脂（１） ７０重量部
・Ｃ．Ｉ．ピグメントブルー１５：３のシアン顔料ペースト １００重量部
（顔料固形分３０重量％，水分７０重量％）
シアン顔料ペーストは、製造後に一度も粉末化の工程を経てはいないものを使用した。
【０２４１】
上記材料をニーダー型ミキサーに入れ、混合しながら徐々に開放系の非加圧条件下で昇温した。温度が９０〜１００℃に達した時点で、水相中のシアン顔料の粒子がポリエステル樹脂相へ分配または移行したことを確認した後、さらに３０分間加熱溶融混練を続けた。混練後、分離した熱水をミキサーから排出した後、ミキサーの温度を１３０℃に昇温し、シアン顔料の粒子が分散しているポリエステル樹脂を約３０分間加熱溶融混練をおこなって、シアン顔料の粒子をさらに均一に分散するとともに水分の除去をおこなった。混練後に混練物を冷却し、冷却した混練物を粉砕して粒径１ｍｍ以下のシアン顔料含有ポリエステル樹脂粒子を得た。
【０２４２】
・シアン顔料含有ポリエステル樹脂粒子 １６．７重量部
（シアン顔料の含有量３０重量％）
・架橋ポリエステル樹脂 ８８．３重量部
・負荷電性制御剤 ４重量部
（ジ−ターシャリーブチルサリチル酸のアルミニウム化合物）
【０２４３】
上記材料をヘンシェルミキサーで十分予備混合をおこない、得られた混合物を設定温度１００℃の二軸式押出し機で溶融混練した。
【０２４４】
吐出された溶融混練物は、温度が１３７〜１３９℃を示していた。溶融混練物を冷却後ハンマーミルを用いて約１〜２ｍｍ程度に粗粉砕し、次いでエアージェット方式による微粉砕機で微粉砕した。さらに得られた微粉砕物を多分割分級装置で微粉及び粗粉を同時に厳密に除去して、シアントナー粒子Ｎｏ．１を得た。得られたシアントナー粒子Ｎｏ．１は重量平均粒径が７．２μｍであり、個数平均粒径が５．９μｍであり、粒径４μｍ以下のトナー粒子が１４個数％であり、粒径５．０４μｍ以下のトナー粒子が３４個数％であり、粒径８μｍ以上のトナー粒子が２９体積％であり、粒径１０．０８μｍ以上のトナー粒子が３．５体積％であった。
【０２４５】
シアントナー粒子Ｎｏ．１の１００重量部に対して、疎水性アルミナ微粉体Ｎｏ．１を１．５重量部と、チタン酸ストロンチウム粉体（長さ平均粒径１．２μｍ，ＢＥＴ比表面積２．３ｍ² ／ｇ）を０．５重量部を混合してシアントナーＮｏ．１を調製した。シアントナー粒子Ｎｏ．１及びシアントナーＮｏ．１の物性を表３及び表４に示す。
【０２４６】
シアントナーＮｏ．１の５重量部と、含窒素シアンカップリング剤とシリコーン樹脂とを反応させた樹脂約０．５重量％で被覆されている平均粒径３８μｍの磁性Ｍｎ−Ｍｇ−Ｆｅ系フェライトキャリア粒子９５重量部とを混合して磁気ブラシ現像用の二成分系現像剤を調製した。
【０２４７】
この二成分系現像剤を市販の普通紙フルカラー複写機（カラーレーザーコピア８００）の改造機に導入し転写材として普通紙を使用して複写試験を行った。この時定着ローラーは、厚さ５ｍｍのアルミ製の芯金上に厚さ２ｍｍのＨＴＶ（高温加硫型）シリコーンゴム層，この外側に厚さ５０μｍのフッ素ゴム層，この外側に厚さ２３０μｍの付加型シリコーンゴム層を有した直径６０ｍｍのものを用い、加圧ローラーには、厚さ５ｍｍのアルミ製の芯金上に厚さ１．５ｍｍのＨＴＶシリコーンゴム層，この外側に厚さ５０μｍのフッ素ゴム層，この外側に厚さ２００μｍの付加型シリコーンゴム層を有したものを用いた。
【０２４８】
定着温度は１５５℃、定着スピードは２００ｍｍ／ｓｅｃとし、ジメチルシリコーンオイルを定着ローラーに塗布しながら、普通紙にシアントナー画像を定着せしめた。
【０２４９】
シアンカラートナーの着色力Ｄ_0.5を測定するために、上記のローラー構成と同じ外部定着機を用意し、普通紙上のシアンカラートナー量Ｍ／Ｓを０．５ｍｇ／ｃｍ²に調製した画像を定着せしめ、光沢度１５％のシアンカラー画像を形成し、Ｘ−Ｒｉｔｅ社製Ｘ−Ｒｉｔｅ ４０４Ａカラー反射濃度計を用いて画像濃度を測定した。結果はＤ_0.5は、１．４２であった。
【０２５０】
グロス（光沢度）の測定には、日本電色社製ＶＧ−１０型光沢度計を用いた。測定にあたっては、まず定電圧装置により６Ｖにセットし、次いで投光角度、受光角度をそれぞれ６０度に合わせ、０点調整及び標準板を用い、標準設定の後に試料台の上に白色紙を３枚上に重ねその上に定着画像を測定を行い、標示部に示される数値を％単位で読み取った。
【０２５１】
常温常湿（２３℃，６０％ＲＨ）の環境下で、コントラスト電位３００Ｖの条件で画出ししたところ、画像の色調は彩度に優れ、あざやかであった。６万枚の多数枚耐久においてもカブリのないオリジナル画像に忠実なシアン色画像が得られた。フルカラー複写機内でのシアンカラートナーの搬送性は良好であり、シアンカラートナーの濃度検知も良好におこなわれ、画像濃度も安定していた。また、ＯＨＰフィルムにシアントナー像を転写し、定着されたものをオーバーヘッドプロジェクターで透光したところ、透光性に優れ、鮮明なシアン色の像がスクリーン上に投影された。
【０２５２】
低温低湿（１５℃，１０％ＲＨ）環境下及び高温高湿（３２．５℃，８５％ＲＨ）環境下においても良好なシアンカラー画像が得られ、環境安定性に優れていた。
【０２５３】
次にカラーレザーコピア８００の改造機を用いて、普通紙の両方の面にベタ画像を形成する両面定着をおこなった。
【０２５４】
シアントナーＮｏ．１は着色力が高く、普通紙上のトナーの乗り量を少なめに設定できるため、通常一回定着後の普通紙のカールがほどんど見られず、それゆえ、複写機内での普通紙の搬送性も良好であった。定着画像濃度１．７のベタ画像を連続して１００００枚の両面定着の多数枚耐久を試みたが、ジャム（紙づまり）の発生は見られなかった。
【０２５５】
また得られた画像表面には、シリコーンオイルの塗布ムラ，スジムラ等のオイルに起因する画像欠陥は見られず、疎水性アルミナ微粉体Ｎｏ．１はシリコーンオイル吸着性に優れていることが知見された。
【０２５６】
また、多数枚耐久後の感光ドラムや転写ドラム表面からは、シリコーンオイルは検出されず、定着画像表面からのオイル転着はないか又は極めて少ないと判断された。
【０２５７】
比較例１
シアントナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性シリカ微粉体１．５重量部のみを外添して比較シアントナーＮｏ．１を調製した。比較シアントナーＮｏ．１の物性を表３及び４に示す。比較シアントナーＮｏ．１を使用して実施例１と同様にして二成分系現像剤を調製し、実施例１と同様にして評価した。評価結果を表５に示す。
【０２５８】
比較例２
シアントナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性酸化チタン微粉体１．５重量部のみを外添して比較シアントナーＮｏ．２を調製した。比較シアントナーＮｏ．２の物性を表３及び４に示す。比較シアントナーＮｏ．２を使用して実施例１と同様にして二成分系現像剤を調製し、実施例１と同様にして評価した。評価結果を表５に示す。
【０２５９】
比較例３
シアントナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性シリカ微粉体１．５重量部と、チタン酸ストロンチウム粉体（長さ平均粒径１．２μｍ，ＢＥＴ比表面積２．３ｍ² ／ｇ）を０．５重量部とを外添して比較シアントナーＮｏ．３を調製した。比較シアントナーＮｏ．３の物性を表３及び表４に示す。比較シアントナーＮｏ．３を使用して実施例１と同様にして二成分系現像剤を調製し、実施例１と同様にして評価した。評価結果を表５に示す。
【０２６０】
比較例４
シアントナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性酸化チタン微粉体１．５重量部と、チタン酸ストロンチウム粉体（長さ平均粒径１．２μｍ，ＢＥＴ比表面積２．３ｍ² ／ｇを０．５重量部とを外添して比較シアントナーＮｏ．４を調製した。比較シアントナーＮｏ．４の物性を表３及び表４に示す。比較シアントナーＮｏ．２を使用して実施例１と同様にして二成分系現像剤を調製し、実施例１と同様にして評価した。評価結果を表５に示す。
【０２６１】
比較例５乃至８
架橋ポリエステル樹脂（１）のかわりに、架橋ポリエステル樹脂（４），架橋ポリエステル樹脂（５），線状ポリエステル樹脂（６）又は架橋ポリエステル樹脂（７）を使用することを除いて、実施例１と同様にして比較シアントナー粒子Ｎｏｓ１乃至４を得た。
【０２６２】
比較シアントナー粒子Ｎｏ．１乃至４の各１００重量部に対して、表２に示す疎水性シリカ微粉体を１．５重量部外添して比較シアントナーＮｏｓ５乃至８を調製した。比較シアントナー粒子Ｎｏｓ１乃至４及び比較シアントナーＮｏｓ５乃至８の物性を表３及び表４に示す。
【０２６３】
比較シアントナーＮｏｓ５乃至８を使用して実施例１と同様にして二成分系現像剤を調製し、実施例１と同様にして評価した。評価結果を表５に示す。
【０２６４】
比較例９乃至１２
比較シアントナー粒子Ｎｏｓ１乃至４の各１００重量部に対して、表２に示す疎水性酸化チタン微粉体を１．５重量部外添して比較シアントナーＮｏｓ９乃至１２を調製した。比較シアントナーＮｏｓ９乃至１２の物性を表４に示す。
【０２６５】
比較シアントナーＮｏｓ９乃至１２を使用して実施例１と同様にして二成分系現像剤を調製し、実施例１と同様にして評価した。評価結果を表５に示す。
【０２６６】
比較例１３
架橋ポリエステル樹脂（４） １００重量部
シアン着色剤（Ｃ．Ｉ．ピグメントブルー１５：３） ５重量部
負荷電性制御剤 ４重量部
（ジーターシャリーブチルサリチル酸のアルミニウム化合物）
【０２６７】
上記材料を使用して実施例１と同様にして溶融混練，冷却，粉砕及び分級を行って比較シアントナー粒子Ｎｏ．５を調製し、実施例１と同様にして比較シアントナーＮｏ．１３を調製し、実施例１と同様にして評価した。評価結果を表５に示す。
【０２６８】
比較例１４乃至１６
架橋ポリエステル樹脂（４）のかわりに、架橋ポリエステル樹脂（５），線状ポリエステル樹脂（６）又は架橋ポリエステル樹脂（７）を使用することを除いて比較例１３と同様にして比較シアントナー粒子Ｎｏｓ６乃至８を調製し、実施例１と同様にして比較シアントナーＮｏｓ１４乃至１６を調製し、実施例１と同様にして評価した。結果を表５に示す。
【０２６９】
【表３】

【０２７０】
【表４】

【０２７１】
【表５】

【０２７２】
ＯＨＰ定着画像の透光性の評価
Ａ（良い）：透明性に優れ、明暗ムラが無く、色再現性に優れている。
Ｂ（普通）：若干の明暗ムラがあるが、実用上問題ない。
Ｃ（悪い）：明暗ムラがあり、色再現性に劣っている。
【０２７３】
両面定着時のシリコーンオイルによる汚染の有無の評価
Ａ：転写ドラムの転写材担持シートにシリコーンオイルによる汚染がない。
Ｂ：転写ドラムの転写材担持シートにシリコーンオイルによる汚染が少しあるが、転写工程に実質的に影響がない。
Ｃ：転写ドラムの転写材担持シートにシリコーンオイルによる汚染が認められ、転写工程に悪影響を与えている。
【０２７４】
片面定着時の転写材のカールの程度
目視により下記三段階に評価した。
Ａ：ほとんどカールがなく、普通紙の搬送性に何んら問題を生じない。
Ｂ：若干カールが発生するが、普通紙の搬送性に実用上問題を生じない。
Ｃ：カールが発生し、普通紙の裏面に画像を形成する際に問題が生じる場合がある。
【０２７５】
耐久後の感光ドラム表面
６万枚の耐久後に目視により感光ドラム表面を観察し、下記三段階に評価した。
Ａ：耐久初期と実質上差がない。
Ｂ：トナーによるフィルミングが感光ドラム表面に一部分あるが実用上問題がない。
Ｃ：トナーによるフィルミングが感光ドラム表面にあり、画像上に欠陥が生じる場合がある。
【０２７６】
ハイライト部の再現性
耐久初期及び６万枚耐久後の定着画像を目視で三段階に評価した。
Ａ：細線再現性が良好であり、写真画像のハートーン部（ハイライト部）が忠実に再現されている。
Ｂ：滑らかにやや劣るが、実用レベル内である。
Ｃ：滑らかさに劣り、がさつきが目立。
【０２７７】
カブリの評価
カブリは、耐久初期と耐久後の画像の白地部分の白色度をリフレクトメーター（東京電色社製）により測定し、その白色度と普通紙（転写紙）の白色度の差から、カブリ濃度（％）を算出し、評価した。評価基準を以下に示す。
Ａ：非常に良好（１．０％未満）
Ｂ：良好（１．０％以上乃至２．０％未満）
Ｃ：悪い（２．０％以上）
【０２７８】
比較例１７乃至２１
粉砕条件及び分級条件を変えることを除いて実施例１と同様にして比較シアントナー粒子Ｎｏ９乃至１３を調製し、実施例１と同様にして比較シアントナーＮｏ．１７乃至２１を調製し、実施例１と同様にして評価した。比較シアントナー粒子Ｎｏｓ９乃至１３の物性を表６に示し、比較シアントナーＮｏ．１７乃至２１の物性を表７に示し、評価結果を表８に示す。
【０２７９】
実施例２乃至３
架橋ポリエステル樹脂（１）のかわりに、架橋ポリエステル樹脂（２）又は（３）を使用することを除いて、実施例１と同様にしてシアントナー粒子Ｎｏｓ２及び３を調製し、実施例１と同様にしてシアントナーＮｏｓ２及び３を調製し、実施例１と同様にして評価した。シアントナー粒子の物性を表６に示し、シアントナーＮｏｓ２及び３の物性を表７に示し、評価結果を表８に示す。
【０２８０】
実施例４乃至６
疎水性アルミナ微粉体Ｎｏ．１のかわりに、疎水性アルミナ微粉体Ｎｏｓ２乃至４を使用することを除いて実施例１と同様にしてシアントナーＮｏｓ４乃至６を調製し、実施例１と同様にして評価した。シアントナーＮｏｓ４乃至６の物性を表７に示し、評価結果を表８に示す。
【０２８１】
【表６】

【０２８２】
【表７】

【０２８３】
【表８】

【０２８４】
実施例７
・架橋ポリエステル樹脂（１） ５８．３重量部
・Ｃ．Ｉ．ピグメントレッド１２２のマゼンタ顔料ペースト １００重量部
（顔料固形分２５重量％，水分７５重量％）
【０２８５】
マゼンタ顔料ペーストは、製造後に一度も粉末化の工程を経ていないものを使用した。
【０２８６】
上記材料を使用して実施例１と同様にしてマゼンタ顔料含有ポリエステル樹脂粒子を得た。
・マゼンタ顔料含有ポリエステル樹脂粒子 ２０重量部
（マゼンタ顔料の含有量３０重量％）
・架橋ポリエステル樹脂（１） ８６重量部
・負荷電性制御剤 ４重量部
（ジーターシャリーブチルサリチル酸のアルミニウム化合物）
【０２８７】
上記材料を使用して実施例１と同様にしてマゼンタトナー粒子Ｎｏ．１を得た。得られたマゼンタトナー粒子Ｎｏ．１の１００重量部に対して、疎水性アルミナ微粉体Ｎｏ．１を１．５重量部と、チタン酸ストロンチウム粉体（長さ平均粒径１．２μｍ、ＢＥＴ比表面積２．３ｍ² ／ｇ）を０．５重量部を混合してマゼンタトナーＮｏ．１を調製した。マゼンタトナー粒子Ｎｏ．１及びマゼンタトナーＮｏ．１の物性を表９及び１０に示す。
【０２８８】
マゼンタトナーの５重量部と、含窒素シアンカップリング剤とシリコーン樹脂とを反応させた樹脂約１重量％で被覆されている平均粒径３８μｍの磁性Ｍｎ−Ｍｇ−Ｆｅ系フェライトキャリア粒子９５重量部とを混合して磁気ブラシ現像用の二成分系現像剤を調製した。
【０２８９】
二成分系現像剤を使用し、実施例１と同様にして画出し試験をおこなった。マゼンタトナーの着色力Ｄ_0.5 は１．３２だった。
【０２９０】
３万枚の多数枚耐久試験においても、画像濃度は安定しており、ハイライト部分の再現性に優れ、ＯＨＰ画像は透明性に優れていた。
【０２９１】
また、１００００枚の両面耐久試験においても良好な結果を示した。評価結果を表１１に示す。
【０２９２】
実施例８及び９
架橋ポリエステル樹脂（１）のかわりに、架橋ポリエステル樹脂（２）又は（３）を使用することを除いて実施例７と同様にしてマゼンタトナー粒子Ｎｏｓ２及び３を調製し、実施例７と同様にしてマゼンタトナーＮｏｓ２及び３を調製し、実施例７と同様にして評価した。マゼンタトナー粒子Ｎｏｓ２及び３の物性を表９に示し、マゼンタトナーＮｏｓ２及び３の物性を表１０に示し、評価結果を表１１に示す。
【０２９３】
比較例２２
マゼンタトナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性シリカ微粉体１．５重量部のみを外添して比較マゼンタトナーＮｏ．１を調製した。比較マゼンタトナーＮｏ．１の物性を表９及び１０に示す。比較マゼンタトナーＮｏ．１を使用して実施例７と同様にして二成分系現像剤を調製し、実施例７と同様にして評価した。評価結果を表１１に示す。
【０２９４】
比較例２３
マゼンタトナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性酸化チタン微粉体１．５重量部のみを外添して比較マゼンタトナーＮｏ．２を調製した。比較マゼンタトナーＮｏ．２の物性を表９及び１０に示す。比較マゼンタトナーＮｏ．２を使用して実施例７と同様にして二成分系現像剤を調製し、実施例７と同様にして評価した。評価結果を表１１に示す。
【０２９５】
比較例２４乃至２７
架橋ポリエステル樹脂（１）のかわりに、架橋ポリエステル樹脂（４），架橋ポリエステル樹脂（５），線状ポリエステル樹脂（６）又は架橋ポリエステル樹脂（７）を使用することを除いて、実施例４と同様にして比較マゼンタトナー粒子Ｎｏｓ１乃至４を得た。
【０２９６】
比較マゼンタトナー粒子Ｎｏｓ１乃至４の各１００重量部に対して、表２に示す疎水性シリカ微粉体を１．５重量部外添して比較マゼンタトナーＮｏｓ３乃至６を調製した。比較マゼンタトナー粒子Ｎｏｓ１乃至４及び比較マゼンタトナーＮｏｓ３乃至６の物性を表９及び１０に示す。
【０２９７】
比較マゼンタトナーＮｏｓ３乃至６を使用して実施例７と同様にして二成分系現像剤を調製し、実施例４と同様にして評価した。評価結果を表１１に示す。
【０２９８】
比較例２８乃至３１
比較マゼンタトナー粒子Ｎｏｓ１乃至４の各１００重量部に対して、表２に示す疎水性酸化チタン微粉体を１．５重量部外添して比較マゼンタトナーＮｏｓ７乃至１０を調製した。比較マゼンタトナーＮｏｓ７乃至１０の物性を表９及び１０に示す。
【０２９９】
比較マゼンタトナーＮｏｓ７乃至１０を使用して実施例７と同様にして二成分系現像剤を調製し、実施例７と同様にして評価した。評価結果を表１１に示す。
【０３００】
比較例３２
・架橋ポリエステル樹脂（４） １００重量部
・マゼンタ着色剤（Ｃ．Ｉ．ピグメントレッド１２２） ６重量部
・負荷電性制御剤 ４重量部
（ジーターシャリーブチルサリチル酸のアルミニウム化合物）
【０３０１】
上記材料を使用して実施例４と同様にして溶融混練，冷却，粉砕及び分級をおこなって比較マゼンタトナー粒子Ｎｏ．５を調製し、実施例７と同様にして比較マゼンタトナーＮｏ．１１を調製し、実施例７と同様にして評価した。評価結果を表１１に示す。
【０３０２】
【表９】

【０３０３】
【表１０】

【０３０４】
【表１１】

【０３０５】
実施例１０
・架橋ポリエステル樹脂（１） １００重量部
・Ｃ．Ｉ．ピグメントイエロー１７のイエロー顔料ペースト １００重量部
（顔料固形分２０重量％，水分８０重量％）
【０３０６】
イエロー顔料ペーストは、製造後に一度も粉末化の工程を経ていないものを使用した。
【０３０７】
上記材料を使用して、実施例１と同様にしてイエロー顔料含有ポリエステル樹脂粒子を得た。
【０３０８】
・イエロー顔料含有ポリエステル樹脂粒子 ２０重量部
（イエロー顔料の含有量２０重量％）
・架橋ポリエステル樹脂（１） ８４重量部
・負荷電性制御剤 ４重量部
（ジーターシャリーブチルサリチル酸のアルミニウム化合物）
【０３０９】
上記材料を使用して実施例１と同様にしてイエロートナー粒子Ｎｏ．１を得た。得られたイエロートナー粒子Ｎｏ．１の１００重量部に対して、疎水性アルミナ微粉体Ｎｏ．１を１．５重量部と、チタン酸ストロンチウム粉体（長さ平均粒径１．２μｍ，ＢＥＴ比表面積２．３ｍ² ／ｇ）を０．５重量部を混合してイエロートナーＮｏ．１を調製した。イエロートナー粒子Ｎｏ．１及びイエロートナーＮｏ．１の物性を表１２及び１３に示す。
【０３１０】
イエロートナーＮｏ．１の５重量部と、含窒素シアンカップリング剤とシリコーン樹脂とを反応させた樹脂約１重量％で被覆されている平均粒径３８μｍの磁性Ｍｎ−Ｍｇ−Ｆｅ系フェライトキャリア粒子９５重量部とを混合して磁気ブラシ現像用の二成分系現像剤を調製した。
【０３１１】
二成分系現像剤を使用し、実施例１と同様にして画出し試験をおこなった。イエロートナーの着色力Ｄ_0.5 は１．４５であった。
【０３１２】
３万枚の多数枚耐久試験においても、画像濃度は安定しており、ハイライト部分の再現性に優れ、ＯＨＰ画像は透明性に優れていた。
【０３１３】
さらに、１００００枚の両面耐久試験においても良好な結果を示した。評価結果を表１４に示す。
【０３１４】
実施例１１及び１２
架橋ポリエステル樹脂（１）のかわりに、架橋ポリエステル樹脂（２）又は（３）を使用することを除いて実施例１０と同様にしてイエロートナー粒子Ｎｏｓ２及び３を調製し、実施例１０と同様にしてイエロートナーＮｏｓ２及び３を調製し、実施例１０と同様にして評価した。イエロートナー粒子Ｎｏｓ２及び３の物性を表１２に示し、イエロートナーＮｏｓ２及び３の物性を表１３に示し、評価結果を表１４に示す。
【０３１５】
比較例３３
イエロートナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性シリカ微粉体１．５重量部のみを外添して比較イエロートナーＮｏ．１を調製した。比較イエロートナーＮｏ．１の物性を表１２及び１３に示す。比較イエロートナーＮｏ．１を使用して実施例１０と同様にして二成分系現像剤を調製し、実施例１０と同様にして評価した。評価結果を表１４に示す。
【０３１６】
比較例３４
イエロートナー粒子Ｎｏ．１の１００重量部に、表２に示す疎水性酸化チタン微粉体１．５重量部のみを外添して比較イエロートナーＮｏ．２を調製した。比較イエロートナーＮｏ．２の物性を表１２及び１３に示す。比較イエロートナーＮｏ．２を使用して実施例１０と同様にして二成分系現像剤を調製し、実施例１０と同様にして評価した。評価結果を表１４に示す。
【０３１７】
比較例３５乃至３８
架橋ポリエステル樹脂（１）のかわりに、架橋ポリエステル樹脂（４），架橋ポリエステル樹脂（５），線状ポリエステル樹脂（６）又は架橋ポリエステル樹脂（７）を使用することを除いて、実施例１０と同様にして比較イエロートナー粒子Ｎｏｓ１乃至４を得た。
【０３１８】
比較イエロートナー粒子Ｎｏｓ１乃至４の各１００重量部に対して、表２に示す疎水性シリカ微粉体を１．５重量部外添して比較イエロートナーＮｏｓ３乃至６を調製した。比較イエロートナー粒子Ｎｏｓ１乃至４及び比較イエロートナーＮｏｓ３乃至６の物性を表１２及び１３に示す。
【０３１９】
比較イエロートナーＮｏｓ３乃至６を使用して実施例１０と同様にして二成分系現像剤を調製し、実施例４と同様にして評価した。評価結果を表１４に示す。
【０３２０】
比較例３９乃至４２
比較イエロートナー粒子Ｎｏｓ１乃至４の各１００重量部に対して、表２に示す疎水性酸化チタン微粉体を１．５重量部外添して比較イエロートナーＮｏｓ７乃至１０を調製した。比較イエロートナーＮｏｓ７乃至１０の物性を表１３及び表１４に示す。
【０３２１】
比較イエロートナーＮｏｓ７乃至１０を使用して実施例１０と同様にして二成分系現像剤を調製し、実施例１０と同様にして評価した。評価結果を表１４に示す。
【０３２２】
比較例４３
・架橋ポリエステル樹脂（４） １００重量部
・マゼンタ着色剤（Ｃ．Ｉ．ピグメントイエロー１７） ４重量部
・負荷電性制御剤 ４重量部
（ジーターシャリーブチルサリチル酸のアルミニウム化合物）
【０３２３】
上記材料を使用して実施例１０と同様にして溶融混練，冷却，粉砕及び分級をおこなって比較イエロートナー粒子Ｎｏ．５を調製し、実施例１０と同様にして比較イエロートナーＮｏ．１１を調製し、実施例１０と同様にして評価した。評価結果を表１４に示す。
【０３２４】
【表１２】

【０３２５】
【表１３】

【０３２６】
【表１４】

【０３２７】
実施例１３
実施例１のシアントナーＮｏ．１を有する二成分系現像剤、実施例７のマゼンタトナーＮｏ．１を有する二成分系現像剤及び実施例１０のイエロートナーＮｏ．１を有する二成分系現像剤を使用し、実施例１で使用したフルカラー複写機を使用してフルカラーモードで画出し試験をおこない、普通紙の表裏にフルカラー画像を両面定着により形成した。形成されたフルカラー画像は、オリジナル画像と対比しても画質的に優れており、多数枚耐久時においても転写ドラムの転写材担持シートへのシリコーンオイルによる汚染もなく、普通紙のカールの発生も少なく装置内での定着画像を有する普通紙は円滑におこなわれ、両面定着時における定着画像の損傷の発生もなく、ローラへの巻き付き及びオフセット現象の発生もなかった。
【０３２８】
また、ＯＨＰフィルムにフルカラー画像を形成したところフルカラー画像は透光性に優れ、鮮明なフルカラー画像をスクリーンに投影することができた。評価結果を表１５に示す。
【０３２９】
比較例４４
比較例１の比較シアントナーＮｏ．１を有する二成分系現像剤，比較例２２の比較マゼンタトナーＮｏ．１を有する二成分系現像剤及び比較例３３の比較イエロートナーＮｏ．１を有する二成分系現像剤を使用して実施例１３と同様にしてフルカラーモードでの画出し試験をおこなった。評価結果を表１５に示す。
【０３３０】
比較例４５
比較例２の比較シアントナーＮｏ．２を有する二成分系現像剤，比較例２３の比較マゼンタトナーＮｏ．２を有する二成分系現像剤及び比較例３４の比較イエロートナーＮｏ．２を有する二成分系現像剤を使用して実施例１３と同様にしてフルカラーモードでの画出し試験をおこなった。評価結果を表１５に示す。
【０３３１】
比較例４６
比較例５の比較シアントナーＮｏ．５を有する二成分系現像剤，比較例２４の比較マゼンタトナーＮｏ．３を有する二成分系現像剤及び比較例３５の比較イエロートナーＮｏ．３を有する二成分系現像剤を使用して実施例１３と同様にしてフルカラーモードでの画出し試験をおこなった。評価結果を表１５に示す。
【０３３２】
比較例４７
比較例６の比較シアントナーＮｏ．６を有する二成分系現像剤，比較例２５の比較マゼンタトナーＮｏ．４を有する二成分系現像剤及び比較例３６の比較イエロートナーＮｏ．４を有する二成分系現像剤を使用して実施例１３と同様にしてフルカラーモードでの画出し試験をおこなった。評価結果を表１５に示す。
【０３３３】
比較例４８
比較例７の比較シアントナーＮｏ．７を有する二成分系現像剤，比較例２６の比較マゼンタトナーＮｏ．５を有する二成分系現像剤及び比較例３７の比較イエロートナーＮｏ．５を有する二成分系現像剤を使用して実施例１３と同様にしてフルカラーモードでの画出し試験をおこなった。評価結果を表１５に示す。
【０３３４】
比較例４９
比較例８の比較シアントナーＮｏ．８を有する二成分系現像剤，比較例２７の比較マゼンタトナーＮｏ．６を有する二成分系現像剤及び比較例３８の比較イエロートナーＮｏ．６を有する二成分系現像剤を使用して実施例１３と同様にしてフルカラーモードでの画出し試験をおこなった。評価結果を表１５に示す。
【０３３５】
【表１５】

【０３３６】
【発明の効果】
本発明のカラートナーは、定着性，耐オフセット性，混色性，ハイライト部の再現性及び多数枚耐久性の点で総合的に優れており、転写材の両面に定着画像を形成するための各工程を円滑におこなえる。さらに、本発明のカラートナー及び画像形成方法においては、定着時に定着ローラに塗布されるシリコーンオイルを定着画像が吸収又は／及び吸着し、定着画像表面のオイルムラを無くし、転写材の他方の面（裏面）にカラートナー像を転写する際に転写材の一方の面（表面）に付着しているシリコーンオイルが、転写ドラム表面を汚染するという問題も大幅に軽減できる。
【図面の簡単な説明】
【図１】本発明に好適な定着装置を装着したシアントナー，マゼンタトナー及びイエロートナーの３色に加えて、さらにブラックトナーを有しているフルカラー画像形成用のレザービーム複写機（プリンターとしても使用可）の構成を示す縦断面図である。
【図２】定着装置の構成を示す模式図である。
【図３】αタイプのアルミナのＸ線回折パターンを示す図である。
【図４】γタイプのアルミナのＸ線回折パターンを示す図である。
【符号の説明】
１０ａ 定着ローラー
１０ｂ 加圧ローラー
６２ ゴム状部材
６３ フッ素樹脂
Ｃ１ クリーニングブレード[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color toner used for developing an electrostatic image in an image forming method such as electrophotography and electrostatic recording, or a color toner used in a toner jet type image forming method and an image forming method.
[0002]
[Prior art]
In general, in the case of a system in which a transfer material is carried on a transfer drum, a full-color image is obtained by uniformly charging the photoreceptor of the photoreceptor drum by a primary charger and, for example, by laser light modulated by a yellow image signal of a document. Image exposure is performed, an electrostatic charge image is formed on the photosensitive drum, and the electrostatic charge image is developed by a yellow developing device that holds yellow toner to form a yellow toner image. Next, the yellow toner image developed on the photosensitive drum is transferred onto the transferred transfer material by a transfer charger.
[0003]
On the other hand, the photosensitive drum after the development of the electrostatic charge image is neutralized by a neutralizing charger, cleaned by a cleaning means, and then charged again by a primary charger. Similarly, for example, a cyan toner image The cyan toner image is transferred to the transfer material onto which the yellow toner image has been transferred, and the toner images of four colors are transferred to the transfer material, for example, in the same manner as magenta and black. The transfer material having the four color toner images is fixed by the action of heat and pressure with a fixing roller, thereby forming a full color image.
[0004]
The toner used in the color image forming method needs to have good meltability and color mixing properties when heat is applied thereto, has a low softening point, and has a low melt viscosity and a high sharp melt property. Is preferably used.
[0005]
That is, by using a toner having high sharp melt properties, the color reproduction range of a copy can be widened and a color copy faithful to the original image can be obtained.
[0006]
However, such color toners with high sharp melt properties tend to cause an offset phenomenon in which a part of the toner is partially transferred to the surface of the fixing roller at the time of fixing, while heat shrinkage after fixing tends to occur. The transfer material tends to curl easily after fixing.
[0007]
In particular, in the case of a fixing device in a color image forming apparatus, a plurality of toner layers of yellow, cyan, magenta, and black are formed on a transfer material, so that offset and curl tend to occur particularly easily.
[0008]
In recent years, there has been a variety of copying needs, and in addition to the recent ecology boom, the need for double-sided copying that forms images on both sides of transfer materials aimed at reducing paper consumption has been increasing day by day. Therefore, when forming the image on the second side, it is necessary to better improve the curling problem of the transfer material and the offset problem.
[0009]
Under such circumstances, in order to reduce the offset at the time of fixing, conventionally, means such as uniformly applying a release agent such as dimethyl silicone oil to the fixing roller at the time of fixing has been adopted, but there is a point to be further improved. Many.
[0010]
On the other hand, in order to reduce the curling of the transfer material after fixing, a method has been devised to suppress the curling semi-forcefully with a curling roller after the first fixing. A roller is inevitably applied to the surface, and a roller mark is left on the image, and the structure of the main body is complicated.
[0011]
If curling occurs on the transfer material after fixing the toner image on one side of the transfer material, it becomes difficult to smoothly transfer the transfer material through the refeed roller section for performing double-sided fixing or the transfer material conveyance path.
[0012]
Furthermore, when a color toner image is transferred to the back surface of the transfer material, there is a problem that the silicone oil adhering to the surface of the transfer material after the first fixing has contaminated the transfer drum surface when the back surface image is formed. It's easy to do. When a large amount of silicone oil adheres to the transfer drum, it is difficult to uniformly wrap the transfer material around the transfer drum, the number of transfers increases, the performance of the sheet surface of the transfer drum changes, and the toner transferability may decrease. It was.
[0013]
U.S. Pat. US Pat. No. 5,437,949 proposes a color toner having a specific particle size distribution in order to improve the coloring power of the color toner. Japanese Patent No. 5529865 proposes an image forming method in which double-sided fixing is smoothly performed by adjusting the particle size distribution of color toners. However, it is excellent in durability of a large number of sheets, and both sides of a full-color image can be fixed more smoothly. There is a long-awaited color toner and image forming method.
[0014]
U.S. Pat. US Pat. No. 5,652,075 proposes a color toner which defines the particle size distribution of pigment particles contained in the color toner particles. No. 5607806 proposes a toner externally added with low crystalline alumina powder. 800117A1 has been proposed as a toner with improved fixability, color mixing, and offset resistance, but it has excellent durability and color toner and image formation that can fix both sides of a full color image more smoothly. A method is awaited.
[0015]
[Problems to be solved by the invention]
An object of the present invention is to provide a color toner and an image forming method in which the above problems are solved.
[0016]
SUMMARY OF THE INVENTION An object of the present invention is to provide a color toner which does not cause a decrease in image density or blur even when continuous copying or continuous printing of a color original having a large image area is performed.
[0017]
An object of the present invention is to provide a color toner that can form a clear image without fogging and has excellent durability stability.
[0018]
It is a further object of the present invention to provide a color toner with less contamination on the surface of the photoreceptor and the transfer drum.
[0019]
An object of the present invention is to provide a color toner having excellent fluidity and excellent development fidelity and transferability.
[0020]
An object of the present invention is to provide a color toner that is less susceptible to humidity and temperature environments and has stable tribocharging properties.
[0021]
An object of the present invention is to provide a color toner that is excellent in fixability and excellent in OHP transparency.
[0022]
The object of the present invention is to reduce curl after the transfer material is normally fixed once, and to smoothly convey the transfer material when forming an image on both sides of the transfer material. It is an object of the present invention to provide an image forming method capable of obtaining a non-color image.
[0023]
An object of the present invention is to provide an image forming method capable of obtaining good color images on both sides of a transfer material without narrowing the color reproducibility of a copy or print.
[0024]
[Means for Solving the Problems]
  The present invention is a color toner having (i) color toner particles containing at least a binder resin and a colorant, and (ii) an external additive. (A) The color toner has a weight average particle diameter of 5 to 8 μm. The number average particle size is 4.5 to 7.5 μm, the number of particles having a particle size of 4 μm or less in the number distribution of the color toner is 5 to 40% by number, and the particle size in the volume distribution of the color toner is 10.08 μm. (B) strontium titanate powder with the above particles being 7% by volume or lessIsAn inorganic powder and a hydrophobic alumina fine powder are externally added to the color toner particles as external additives. The inorganic powder has a length average particle size of 0.2 to 2 μm, and the hydrophobic alumina fine powder. Has a length average particle size of 0.005 to 0.1 μm, (c) the binder resin is a polyester resin crosslinked with a crosslinking agent, and (d) the color toner particles have a chloroform insoluble content. (E) The color toner has a storage elastic modulus (G ′) at a temperature of 130 ° C.₁₃₀) Is 2 × 10³~ 2x10⁴[Dyn / cm²Storage elastic modulus at a temperature of 170 ° C. (G ′₁₇₀) Is 5 × 10³~ 5x10⁴[Dyn / cm²] And G ′₁₇₀/ G '₁₃₀The present invention relates to a color toner having a value of 0.25 to 10.
[0025]
  The present invention further includes (1) charging the electrostatic image carrier, exposing the charged electrostatic image carrier to form an electrostatic image on the electrostatic image carrier, and converting the electrostatic image to a color toner. A color toner image is formed on the electrostatic image carrier by developing with the developer having the toner, the color toner image on the electrostatic image carrier is transferred to one surface of the transfer material, and the transferred color toner image is heated. A color image is formed on one surface of the transfer material by applying heat and pressure to one surface of the transfer material by the pressing means, and (2) the color toner remaining on the electrostatic charge image carrier after the transfer is cleaned by the cleaning means. A developer that cleans, charges the cleaned electrostatic image carrier, exposes the charged electrostatic image carrier to form an electrostatic image on the electrostatic image carrier, and forms the electrostatic image on the electrostatic image carrier. To develop a color toner image on the electrostatic image carrier Then, the color toner image on the electrostatic image bearing member is transferred to the other surface of the transfer material having the fixed image of the color toner image on one surface, and the transferred color toner image is transferred to the transfer material by heating and pressing fixing means. The color toner used for forming a color image on both sides of the transfer material is an image forming method in which a fixed image of a color toner image is formed on both sides of the transfer material by heat and pressure fixing to the other surface of the transfer material. (I) color toner particles containing at least a binder resin and a colorant, and (ii) an external additive, (a) the color toner has a weight average particle diameter of 5 to 8 μm, and has a number average The particle size is 4.5 to 7.5 μm, the particle size distribution of 4 μm or less in the color toner number distribution is 5 to 40% by number, and the color toner volume distribution of particle size 10.08 μm or more is 7 Volume% or less (B) Strontium titanate powderIsAn inorganic powder and a hydrophobic alumina fine powder are externally added to the color toner particles as external additives. The inorganic powder has a length average particle size of 0.2 to 2 μm, and the hydrophobic alumina fine powder. Has a length average particle size of 0.005 to 0.1 μm, (c) the binder resin is a polyester resin crosslinked with a crosslinking agent, and (d) the color toner particles have a chloroform insoluble content. (E) The color toner has a storage elastic modulus (G ′) at a temperature of 130 ° C.₁₃₀) Is 2 × 10³~ 2x10⁴[Dyn / cm²Storage elastic modulus at a temperature of 170 ° C. (G ′₁₇₀) Is 5 × 10³~ 5x10⁴[Dyn / cm²] And G ′₁₇₀/ G '₁₃₀The present invention relates to an image forming method characterized by a value of 0.25 to 10.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
As a result of intensive studies on the image density, highlight reproducibility, fine line reproducibility, and the like of the developer, the present inventors have found that the toner has a weight average particle diameter of 5 to 8 μm and a specific fine powder as an external additive. It was found that the toner exhibits excellent fluidity when contained as a toner and can be developed faithfully with respect to the electrostatic charge image on the photoreceptor. Furthermore, when double-sided fixing is considered, it is possible to increase the apparent image density by filling the gaps between the toner particles without using a toner having the above-mentioned particle size without overlapping the toner on the transfer material. It is not only advantageous for curling problems when fixing on both sides, but also has a cost advantage in that it can reduce the amount of toner required to produce a given image density. It was.
[0027]
Furthermore, the present inventors diligently studied the problems of toner coloring power, toner particle size, and curling. As a result, the amount of unfixed toner (M / S) on the transfer material was determined as M / S = 0.5 mg / cm.²The image density after fixing once (D_0.5) Has a coloring power of 1.2 or more, the above-described effects are further remarkable.
[0028]
The color toner of the present invention has a weight average particle diameter of 5 to 8 μm, a number average particle diameter of 4.5 to 7.5 μm, and 5 to 40 particles having a particle diameter of 4 μm or less in the number distribution of the color toner. %, And particles having a particle diameter of 10.08 μm or more in the volume distribution of the color toner are 7% by volume or less.
[0029]
When the weight average particle diameter of the toner is larger than 8 μm, it means that there are few fine particles that can contribute to high image quality, and it is easy to obtain a high image density and has the advantages of excellent toner fluidity. Therefore, it is difficult to faithfully adhere to the fine electrostatic charge image, and the reproducibility of the highlight portion is lowered, and the resolution is also lowered. In addition, the toner tends to overload the electrostatic charge image more than necessary, and the toner consumption tends to increase.
[0030]
On the contrary, when the weight average particle diameter of the toner is smaller than 5 μm, the charge amount per unit weight of the toner becomes high, and the decrease in image density, particularly the decrease in image density under low temperature and low humidity becomes remarkable. This is not suitable for applications with a high image area ratio such as graphic images.
[0031]
Further, when the thickness is smaller than 5 μm, the contact charging with the carrier is not easily performed, the amount of toner that cannot be sufficiently charged increases, and the fog due to scattering to the non-image portion becomes conspicuous. In order to cope with this, it is conceivable to reduce the diameter of the carrier in order to increase the specific surface area of the carrier. However, with toner having a weight average diameter of less than 5 μm, toner self-aggregation easily occurs, and uniform mixing with the carrier can be achieved in a short time. In the continuous toner replenishment durability, fogging tends to occur.
[0032]
In the toner of the present invention, toner particles having a particle diameter of 4 μm or less are preferably 5 to 40% by number, and preferably 5 to 25% by number of the total number of particles. If the number of toner particles having a particle diameter of 4 μm or less is less than 5% by number, it means that there are few fine toner particles that are essential components for high image quality. As the toner is continuously used, the effective toner particle component decreases, the balance of the toner particle size distribution shown in the present invention is deteriorated, and the image quality gradually decreases.
[0033]
Further, when the number of toner particles having a particle diameter of 4 μm or less exceeds 40% by number, the toner particles tend to be aggregated with each other and often behave as a toner lump having a particle diameter larger than the original particle size. Is likely to be formed, the resolution is lowered, or the density difference between the edge portion and the inside of the electrostatic charge image is increased, and the image tends to be hollow. Furthermore, it is preferable in terms of image quality improvement that the particle size is 10.08 μm or more is 7% by volume or less.
[0034]
More preferably, the particle size of 8 μm or more is 10 to 45% by volume, preferably 15 to 40% by volume. If it exceeds 45% by volume, the image quality deteriorates and toner is excessively loaded, leading to an increase in toner consumption. On the other hand, if it is less than 10% by volume, the image quality tends to be lowered due to a decrease in fluidity of the toner.
[0035]
Further, in order to further improve the effect of the present invention, the particle size of 5.04 μm or less is 7 to 50% by number, more preferably 10 to 45% by number for the purpose of improving the chargeability and fluidity of the toner.
[0036]
Next, the coloring power of the toner will be described.
[0037]
The coloring power of the toner used in the present invention is determined by the amount of unfixed toner (M / S) on the transfer material: M / S = 0.5 mg / cm²Image density after normal fixing (D_0.5) Is preferably 1.2 or higher, more preferably 1.3 or higher.
[0038]
Generally, as the toner particle size is reduced, the interval between toner particles before fixing on a transfer material is narrowed, and as a result, a high image density is exhibited with a small amount. On the other hand, considering the curling of the transfer material after fixing, (1) the larger the toner loading amount, (2) the lower the melt viscosity of the toner, (3) the higher the fixing temperature, the more likely the curling occurs. Curling becomes prominent in proportion to the amount of toner loaded.
[0039]
Therefore, the present inventors have intensively studied to reduce the curl so that both sides can be fixed. As a result, the toner D having the above-described toner viscosity distribution can be obtained._0.5Found that the toner loading amount was reduced when the toner exhibited a coloring power of 1.2 or more, the required image density was satisfied, and as a result, curling could be reduced, and smooth conveyance to second-side image formation could be successfully achieved. It is.
[0040]
Further, since the electrostatic charge image on the photosensitive drum is developed with a small amount of toner, it is advantageous for transfer, and is effective in reducing scattering and preventing hollowing out. This is extremely effective for improving the image quality.
[0041]
However, conversely D_0.5If the value is larger than 1.8, this means that the pigment content in the toner is extremely high, and poor fixing and fog are likely to be a problem.
[0042]
Therefore, the toner D used in the present invention_0.5Is 1.2 or more and 1.8 or less, preferably 1.3 or more and 1.7 or less.
[0043]
In the color toner of the present invention, (i) as the inorganic powder, strontium titanate powder having a length average particle diameter of 0.2 to 2 μm, cerium oxide powder having a length average particle diameter of 0.2 to 2 μm, or length Calcium titanate powder having an average particle diameter of 0.2 to 2 μm and (ii) hydrophobic alumina fine powder having an average particle diameter of 0.005 to 0.1 μm are externally added to the color toner particles. The color toner particles are externally added with specific inorganic fine powder having a length average particle diameter of 0.2 to 2 μm and hydrophobic alumina fine powder having a length average particle diameter of 0.005 to 0.1 μm. The toner has improved fluidity, durability of a large number of sheets, and environmental stability, and occurrence of fogging in a non-image area is also suppressed.
[0044]
The inorganic powder is preferably added in an amount of 0.01 to 2 parts by weight, more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the color toner particles, in order to achieve the above effect satisfactorily. good.
[0045]
The hydrophobic alumina fine powder is preferably added in an amount of 0.5 to 5 parts by weight, more preferably 0.6 to 3 parts by weight based on 100 parts by weight of the color toner particles in order to achieve the above effect. good.
[0046]
Hydrophobic alumina fine powder has better absorbability of silicone oil than hydrophobic silica fine powder and hydrophobic titanium oxide fine powder.
[0047]
In particular, in addition to inorganic powder, when color fine particles are made of alumina fine powder surface-treated with a silane-based organic compound, color toner charging is stabilized, fluidity is imparted, and silicone oil absorbability is improved. Very good in terms.
[0048]
The inventors of the present invention have studied to stabilize the charge and increase the silicone oil absorbency without reducing the fluidity imparting ability of the alumina fine powder. It has been found that surface-treated alumina fine powder is particularly useful. In particular, activated alumina having a γ-type crystal structure has high surface activity and is effective for the present invention.
[0049]
In the present invention, the BET specific surface area is 130 m in the hydrophobized state.²/ G or more (more preferably, 150 to 400 m²/ G). BET specific surface area is 130m²When it is at least / g, absorption and adsorption of silicone oil are further improved.
[0050]
In the present invention, surface-treated alumina fine powder obtained by hydrophobizing alumina fine powder obtained by pyrolyzing aluminum ammonium carbonate hydroxide fine powder represented by the following general formula (I) or (II) is particularly effective. Is.
[0051]
NH_FourAlO (OH) HCO_Three  (I)
NH_FourAlCO_Three(OH)₂      (II)
[0052]
Formula NH4AlO (OH) HCO_ThreeOr NH_FourAlCO_Three(OH)₂It is preferable to sinter the aluminum ammonium carbonate hydroxide represented by, for example, within a temperature range of 300 to 1200 ° C. in an oxygen atmosphere to obtain an alumina fine powder. For example, the following formula
2NH_FourAlCO_Three(OH)₂→ Al₂O_Three+ 2NH_Three+ 3H₂O + 2CO₂After the chemical reaction, the alumina fine powder obtained is preferable. When the firing temperature is in the range of 300 to 1200 ° C., the activity is high, and alumina having a high BET specific surface area is obtained in a high yield.
[0053]
When the firing temperature is higher than 1200 ° C., the proportion of alumina having an α-type crystal structure in the produced alumina fine powder increases rapidly. Naturally, the alumina fine powder undergoes structural growth, the primary particle size increases, and the BET specific surface area decreases. In addition, the degree of agglomeration between the alumina fine particles is increased, and a great deal of energy is required to disperse the alumina fine powder in the treatment process. With such an alumina fine powder, it is difficult to produce a fine powder with few aggregated particles. .
[0054]
On the other hand, when the firing temperature is lower than 300 ° C., complete or sufficient thermal decomposition of aluminum ammonium carbonate hydroxide is difficult to be performed, and H generated in the produced alumina fine powder.₂O, NH_Three, CO₂The gas components such as are left behind. In that case, even if an attempt is made to perform a hydrophobic treatment uniformly, the degree of hydrophobicity cannot be increased to the target level, and even if the apparent degree of hydrophobicity is increased, it is difficult to obtain a stable chargeability, and many sheets Various problems are likely to occur due to durability. A more preferable firing temperature is 300 ° C. to 1100 ° C., more preferably 400 ° C. to 1100 ° C.
[0055]
Next, the hydrophobizing agent for alumina fine powder will be described.
[0056]
The hydrophobizing agent may be appropriately selected according to the control of the triboelectric charging characteristics of the color toner and the stabilization of the triboelectric charging of the color toner in a high humidity environment. For example, silane-based organic compounds such as alkylalkoxysilanes, siloxanes, silanes, and silicone oils that do not themselves thermally decompose at the reaction treatment temperature are preferable.
[0057]
Particularly preferred is a silane coupling agent. It is particularly preferable to use an alkylalkoxysilane represented by the following general formula, which is volatile and has both a hydrophobic group and a reactive bonding group.
[0058]
[Outside 1]

[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group or a methacryl group, and n represents an integer of 1 to 3. Show
[0059]
More preferably,
[0060]
[Outside 2]

[Wherein, a represents an integer of 4 to 12, and b represents an integer of 1 to 3].
[0061]
When a in the general formula is less than 4, the treatment becomes easy but it is difficult to obtain good hydrophobicity. Moreover, when a is larger than 13, the hydrophobicity is sufficient, but the coalescence of fine powders increases and the fluidity imparting ability tends to decrease. On the other hand, if b is larger than 3, the reactivity is lowered and it is difficult to obtain good hydrophobicity. Therefore, in the present invention, a is preferably 4 to 12, more preferably 4 to 8, and b is preferably 1 to 3, more preferably 1 to 2.
[0062]
For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethyl Examples thereof include methoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane and the like.
[0063]
The processing amount of the silane coupling agent is 1 to 50 parts by weight, preferably 3 to 45 parts by weight with respect to 100 parts by weight of the alumina fine powder. Hydrophobic alumina fine powder has a hydrophobicity of 30 to 90%, more preferably 40 to 80%.
[0064]
If the degree of hydrophobicity is less than 30%, the amount of electrification due to long-term standing under high humidity decreases, and a mechanism for promoting charging on the apparatus main body side is required, which complicates the apparatus. Further, the absorbability of the silicone oil is lowered, and oil unevenness is likely to occur on the surface of the fixed image. On the other hand, if the degree of hydrophobicity exceeds 90%, it becomes difficult to control the charge of the alumina fine powder itself, and as a result, the toner is likely to be charged up under low humidity.
[0065]
Further, the treated alumina fine powder preferably has a length average particle diameter of 0.005 to 0.1 μm, more preferably 0.005 to 0.05 μm from the viewpoint of imparting fluidity to the color toner.
[0066]
When the length average particle size is larger than 0.1 μm, the fluidity is lowered and the charging of the color toner is liable to be nonuniform, and as a result, toner scattering and fogging are liable to occur, making it difficult to produce a high quality image. On the other hand, when the average particle size is less than 0.005 μm, the hydrophobic alumina fine powder is likely to be embedded on the surface of the color toner particles, the color toner is likely to be deteriorated, and the durability is likely to be lowered. This tendency is more remarkable when applied to sharp melt color toner particles. If it is less than 0.005 μm, the activity of the alumina particles is high, the alumina particles tend to aggregate, and the desired high fluidity is difficult to obtain. The particle size of the hydrophobic alumina fine powder in the present invention is determined by measuring alumina particles of 0.001 μm or more with a transmission electron microscope.
[0067]
Furthermore, in the present invention, the hydrophobic alumina fine powder has a BET specific surface area of 130 m.²/ G or more, preferably 150 to 400 m²/ G is preferable.
[0068]
BET specific surface area is 130m²If it is less than / g, alumina particles that have grown or partly changed in crystal form to alumina having an α-type crystal structure are mixed, which makes it difficult to obtain the desired high fluidity. In addition, although the BET value is very high in the unprocessed stage before the processing, the BET value is likely to be greatly reduced in the processing step. As a result, BET specific surface area is 130m²/ G is a case where alumina particles are not uniformly dispersed in the solution but react with the treating agent in the form of aggregates, or the treating agent itself is self-condensed, This is a case where it is in the form of oil and has adhered to the surface of alumina particles or aggregates, which is not preferred.
[0069]
An effective method for treating the fine alumina powder is to hydrolyze the coupling agent while mechanically dispersing the fine alumina powder so as to have a primary particle size in the solution.
[0070]
The addition amount of the hydrophobic alumina fine powder treated with the silane coupling agent suitable for the present invention is 0.5 to 5 parts by weight, preferably 0.6 to 3 parts by weight based on 100 parts by weight of the toner particles. Preferably it is 0.7-2.5 weight part.
[0071]
When the amount is less than 0.5 parts by weight, the fluidity imparting property to the toner particles is low. Conversely, when the amount is more than 5 parts by weight, the treated alumina fine powder detached from the toner contaminates the carrier surface and causes the carrier itself. This is not preferable because the charge imparting ability is lowered. Further, the released processed alumina fine powder is likely to fly on the surface of the photoreceptor during development, which may cause defective cleaning. Further, when it is used for color toners, if a large amount of treated alumina fine powder is contained, the projected image of OHP tends to be fragile and it is difficult to obtain a clear one.
[0072]
In the color toner of the present invention, a polyester resin crosslinked with a crosslinking agent such as trimellitic acid is used as a binder resin for the color toner particles. The cross-linking of the polyester resin is caused by the storage modulus (G ′₁₃₀ ) Is 2 × 10^Three ~ 2x10^Four [Dyn / cm² Storage elastic modulus at a temperature of 170 ° C. (G ′₁₇₀ ) Is 5 × 10^Three ~ 5x10^Four [Dyn / cm² ] And G ′₁₇₀ / G '₁₃₀ It is necessary to make the value of 0.25-10. In the crosslinking of the polyester resin, it is more preferable that a crosslinked structure is formed by the organometallic compound in the toner particle production stage in addition to the crosslinking with a crosslinking agent such as trimellitic acid. If the color toner satisfies the above viscoelastic characteristics, the color mixture with the color toner of different color tone is good, the offset resistance is excellent, and even when fixing on both sides, the fixed image is damaged or the roller Occurrence of winding is suppressed.
[0073]
Examples of the divalent alcohol component for producing the polyester resin include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5 -Pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, bisphenol A hydroxide, and bisphenol derivatives represented by formula A
[0074]
[Outside 3]

[Wherein, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10. ].
[0075]
Examples of trihydric or higher alcohol components that function as a crosslinking agent for forming a non-linear crosslinked polyester resin include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, and dipenta Erythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, tri Examples include methylolpropane and 1,3,5-trihydroxybenzene. The amount of the trihydric or higher polyhydric alcohol is preferably 0.1 to 1.9 mol% based on the total monomer.
[0076]
In addition, as the divalent acid component for producing the polyester resin, fumaric acid, maleic acid, maleic anhydride, succinic acid, adipic acid, sebacic acid, malonic acid, and these are saturated or unsaturated having 8 to 22 carbon atoms. Aliphatic acid component monomers substituted with saturated hydrocarbon groups; and aromatic acid component monomers include phthalic acid, isophthalic acid, phthalic anhydride, terephthalic acid and ester derivatives thereof.
[0077]
Examples of the trivalent or higher polyvalent carboxylic acid component that functions as a crosslinking agent for forming a nonlinear crosslinked polyester resin include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, Examples include 2,4-naphthalene tricarboxylic acid, 2,5,7-naphthalene tricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and anhydrides and ester compounds thereof. The amount of the trivalent or higher polyvalent carboxylic acid component is preferably 0.1 to 1.9 mol% based on the total monomer.
[0078]
The preferable glass transition temperature of the polyester resin is 50 to 80 ° C, more preferably 51 to 75 ° C. In GPC measurement of the THF-soluble matter of the polyester resin, the number average molecular weight (Mn) is preferably 1000 to 9000, more preferably 1500 to 7500. The molecular weight (Mp) of the main peak is preferably 5000 to 12000, and more preferably 5500 to 11000. It is preferable that the ratio (Mw / Mn) of the weight average molecular weight (Mw) and Mn of the THF soluble part of the polyester resin is 5.0 or less.
[0079]
In particular, the polyester resin is made non-linear with a trivalent or higher polyvalent carboxylic acid component or a trivalent or higher polyhydric alcohol component, and the content of chloroform insoluble matter by the measurement method described later is the weight of the polyester resin. The standard is preferably 0 to 1% by weight (more preferably 0 to 0.9% by weight, and still more preferably 0 to 0.5% by weight).
[0080]
A polyester resin having a THF insoluble content of 1% by weight or less and having a non-linear structure is a polycondensation of a divalent carboxylic acid component or a divalent carboxylic acid ester component and a divalent alcohol component as a first step. As a second step, a linear prepolymer and a divalent carboxylic acid component (or an ester thereof), and a divalent acid component for generating a polyester resin, Fumaric acid, maleic acid, maleic anhydride, succinic acid, adipic acid, sebacic acid, malonic acid and aliphatic acid component monomers in which these are substituted with a saturated or unsaturated hydrocarbon group having 8 to 22 carbon atoms; or aromatic Examples of the group acid component monomer include phthalic acid, isophthalic acid, phthalic anhydride, terephthalic acid and ester derivatives thereof.
[0081]
Examples of the trivalent or higher polyvalent carboxylic acid component for forming the non-linear crosslinked polyester resin include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, and 1,2,4-naphthalene. Examples thereof include tricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and anhydrides and ester compounds thereof. The amount of the trivalent or higher polyvalent carboxylic acid component is preferably 0.1 to 1.9 mol% based on the total monomer.
[0082]
The preferable glass transition temperature of the polyester resin is 50 to 80 ° C, more preferably 51 to 75 ° C. In GPC measurement of the THF soluble part of the polyester resin, the number average molecular weight (Mn) is preferably 1000 to 9000, more preferably 1500 to 7500. The molecular weight (Mp) of the main peak is preferably 5000 to 12000, and more preferably 5500 to 11000. It is preferable that the ratio (Mw / Mn) of the weight average molecular weight (Mw) and Mn of the THF soluble part of the polyester resin is 5.0 or less.
[0083]
In particular, the polyester resin is non-linearized with a trivalent or higher polyvalent carboxylic acid component or a trivalent or higher polyhydric alcohol component, and the content of THF insolubles is 1% by weight based on the weight of the polyester resin. The following is preferable.
[0084]
The crosslinked polyester resin having a THF insoluble content of 1% by weight or less and having a non-linear structure is a first step in which a divalent carboxylic acid component or a divalent carboxylic acid ester component is condensed with a divalent alcohol component. A linear prepolymer is produced by polymerization, and in the second stage, the linear prepolymer, the divalent carboxylic acid component (or ester thereof), the divalent alcohol component, and the trivalent or higher polyvalent carboxylic acid. It is preferably produced by condensation polymerization of an acid component (or its ester anhydride) or a trihydric or higher polyhydric alcohol component.
[0085]
The polyester resin preferably has an acid value of 1 to 30 mg KOH / g (more preferably 3 to 25 mg KOH / g) from the viewpoints of stabilization of triboelectric charging characteristics and stabilization of specific electrophotography in each environment.
[0086]
In particular, as a preferable polyester resin, the following formula (B)
[0087]
[Outside 4]

[Wherein, x and y are integers of 1 or more, and the average value of x + y is 2 to 4].
[0088]
More preferably, the polyester resin having a molecular skeleton represented by the formula (B) has a non-linear structure formed of a polyvalent carboxylic acid component or a polyhydric alcohol component.
[0089]
When the polyester resin having the molecular skeleton represented by the formula (B) is heated with an organometallic compound, a metal ion crosslinked structure is easily formed, and the storage elastic modulus curve of the toner can be well adjusted.
[0090]
When the molecular skeleton represented by the formula (B) is present in the polyester resin, the affinity with the organometallic compound is excellent, and this affinity is further increased in the molecular skeleton represented by the formula (B).
[0091]
[Outside 5]

These π electrons and oxygen atoms donate electrons to the metal contained in the organometallic compound, and have some kind of coordination. This effect is particularly remarkable when the metal atom is aluminum. This is because when an aluminum atom forms three bonds in an organometallic compound, the aluminum atom is in a state where two electrons are missing from an octet of electrons (formation of four pairs of electrons by eight electrons). Therefore, it is considered that the organometallic compound of aluminum tends to increase the number of electrons to eight by receiving two more electrons. It is formed of a metal atom such as aluminum or a metal atom having a valence of 2 or more and a molecular skeleton represented by the formula (B), which is different from the strong metal ion cross-linking with the side chain or terminal carboxyl group of the conventional binder resin. Intertangles between molecules due to chemical affinity are formed. This achieves both low-temperature fixability and high-temperature offset resistance, both of which have not been achieved before, and the following effects (1) to (5), particularly improvement of fixability, due to a new interaction effect between the polyester resin and the organic acid metal compound. It is understood that the transfer efficiency is significantly improved.
[0092]
(1) Offset resistance is improved without increasing the fixing start temperature. Moreover, the toner does not aggregate even when left for a long time in a high temperature (45 ° C.) state, and there is little change in developability in the same state as before leaving.
[0093]
(2) Transferability is extremely good, halftone (intermediate color) development can be faithfully reproduced on transfer paper (or transfer material), and transfer residual toner is reduced. Scratches that occur during toner adhesion and cleaning can be suppressed.
[0094]
(3) The flowability of the color toner is very good, and stable and good chargeability (developability) is maintained even in various environments such as low temperature / low humidity and high temperature / high humidity, and fogging is generated. The toner scattering inside is suppressed.
[0095]
(4) There is little contamination to the charging member such as the developing sleeve and carrier particles, and good image formation with developability equivalent to the initial value can be achieved even in long-term use.
[0096]
(5) When the color toner is produced, the dispersibility of the colorant in the polyester resin is good, and a sufficient image density can be achieved by adding a small colorant. If the dispersibility of the colorant is good, the classified fine powder in the classification step after fine pulverization can be easily reused during the production of the toner.
[0097]
A more preferable polyester resin is represented by the formula -C-D-C-D- in which two or more molecular skeletons represented by the formula (B) are linked.
[Wherein C is
[0098]
[Outside 6]

(Wherein x and y represent an integer of 1 or more),
[0099]
[Outside 7]

And a polyester resin that is made non-linear with a trivalent or higher polyvalent carboxylic acid or polyhydric alcohol.
[0100]
A polyester resin having a molecular skeleton represented by the formula -C-D-C-D and having a nonlinear structure is represented by the following formula (E):
[0101]
[Outside 8]

(Wherein x and y are integers of 1 or more and the average value of x + y is 2 to 4). A prepolymer is produced by condensation polymerization of a bisphenol derivative represented by It can be produced by polycondensing a diol, a dicarboxylic acid, and a trivalent or higher polyvalent carboxylic acid or a trivalent or higher polyhydric alcohol.
[0102]
It is not fully understood why the molecular skeleton represented by the formula (B) specifically acts with the organometallic compound, but the flexibility inherent in this molecular chain tends to form a conformation that easily interacts. (Molecular configuration interaction) is considered to be related to the electron donating property of the phenyl group having an electron donating property at the P position and the -CH = CH- π electron donating interaction.
[0103]
On the other hand, the bisphenol derivative is represented by the following formula (F)
[0104]
[Outside 9]

In the case of having a propoxy group, a methyl group is present, so that the above-mentioned remarkable effect cannot be found due to its steric hindrance.
[0105]
Further, the following formula (G)
[0106]
[Outside 10]

In the molecular skeleton formed from ethylene glycol and terephthalic acid, a remarkable effect cannot be found, and the following formula (H)
[0107]
[Outside 11]

It is formed by ethylene glycol and fumaric acid, and a remarkable effect cannot be found even in a molecular skeleton.
[0108]
In the color toner of the present invention, the chloroform insoluble content of the color toner particles is 0 to 20 mg / g. The chloroform insoluble content of the color toner particles is a value measured by the following measuring method.
[0109]
Method for measuring chloroform insoluble matter in color toner particles
When an external additive is externally added to the color toner particles, the chloroform-insoluble matter is measured after removing the external additive from the color toner particles. Alternatively, the chloroform insoluble content of the external additive externally added to the color toner particles is measured, and the chloroform insoluble content of the color toner to which the external additive is externally added is measured. The value obtained by subtracting the amount of insoluble chloroform is defined as the amount of insoluble chloroform in the color toner particles.
[0110]
1 g of color toner particles is added to 50 ml of chloroform at room temperature, stirred, and then dispersed by ultrasonic waves for 5 minutes. The obtained chloroform solution was filtered with a membrane filter (weight W₁ The chloroform-insoluble matter is filtered off according to g). Weight of membrane filter carrying chloroform insoluble matter after drying membrane filter carrying chloroform insoluble matter and removing chloroform (W₂ g) is measured, and the weight of chloroform-insoluble matter per 1 g of color toner particles is calculated.
[0111]
Weight of insoluble matter in chloroform (mg / 1g) = W₂ -W₁
Weight W₁ And W₂ Measure to the nearest 0.1 mg. Examples of the membrane filter include a fluoropore membrane filter (Type FP-100; pore size 10.00 μm; diameter 47 mm) manufactured by Sumitomo Electric Industries, Ltd.
[0112]
A chloroform insoluble content per gram of color toner particles of 0 to 20 mg / 1 g means that the colorant having a small particle diameter is small and finely dispersed in the polyester resin in which the colorant is crosslinked. Furthermore, it means that the cross-linked polyester resin constituting the color toner particles has few resin components having an extremely large molecular weight insoluble in chloroform.
[0113]
The color toner particles have a chloroform insoluble content of 0 to 20 mg / 1 g (more preferably 0 to 15 mg / 1 g), and the storage modulus of the color toner at a temperature of 130 ° C. is 2 × 10.^Three ~ 2x10^Four [Dyn / cm] and storage elastic modulus at a temperature of 170 ° C. (G ′₁₇₀ ) Is 5 × 10^Three ~ 5x10^Four [Dyn / cm² ] And G ′₁₇₀ / G '₁₃₀ When the value of is 0.25 to 10 (more preferably 0.5 to 10, more preferably 1 to 10), a color fixed image, a multicolor fixed image and a full color fixed image of an OHP film used for an overhead projector Excellent light transmission, excellent color mixing between color toners during heat and pressure fixing, excellent fixability, excellent offset resistance, good balance between fixability and offset resistance, and transfer material Even if full-color images are formed on both sides of the surface by heat and pressure fixing, there is little gloss on the front and back surfaces, there is little difference in image quality, and the occurrence of damage to the fixed images on the surface that undergoes the heat and pressure fixing process twice is suppressed. The
[0114]
A known dye or / and pigment is used as a colorant for the color toner.
[0115]
As a coloring pigment for magenta toner, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207.209; I. Pigment violet 19; C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35, etc. are mentioned.
[0116]
Although the pigment alone may be used, it is more preferable from the viewpoint of the image quality of the full-color image that the combination of the dye and the pigment improves the sharpness.
[0117]
Examples of the magenta toner dye include C.I. I solvent red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; I. Disper thread 9; I. Solvent Violet 8, 13, 14, 21, 27; C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. B. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; I. Basic violet 1,3,7,10,14,15,21,25,26,27,28 etc. are mentioned.
[0118]
Examples of the color pigment for cyan toner include C.I. I. Pigment blue 2, 3, 15, 16, 17; I. Bat Blue 6; C.I. I. Acid Blue 45 or a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on a phthalocyanine skeleton having a structure represented by the following formula.
[0119]
[Outside 12]

[Wherein n represents an integer of 1 to 5]
[0120]
As a coloring pigment for yellow, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 83, 97, 180; I. Examples include bat yellow 1, 3, 20 and the like.
[0121]
The amount of the colorant used is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 12 parts by weight, and most preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
[0122]
In order to prepare the color toner particles used in the present invention, a polyester resin and a pigment or dye as a colorant, and if necessary, a charge control agent and other additives are sufficiently mixed by a mixer such as a ball mill and then heated. Using a heat kneader such as a roll, kneader, or extruder, the pigments or dyes are dispersed or dissolved in the resin mixed with each other by melting, kneading and kneading, cooling and solidifying, and grinding and strict classification To obtain color toner particles.
[0123]
Unfixed toner amount (M / S) is M / S = 0.5 mg / cm² The image density after fixing once (D_0.5 However, in order to obtain a color toner having a coloring power of 1.2 or more and 1.8 or less, the following pigment dispersion method is preferred.
[0124]
In order to improve the dispersion state of the pigment particles in the color toner particles, the first polyester resin and the paste pigment containing 5 to 50% by weight of the pigment particles insoluble in the dispersion medium are mixed with a kneader or a mixer. The first polyester resin is melted by heating while mixing under non-pressurization, and the paste pigment (that is, the pigment in the liquid phase) is transferred to the molten resin phase of the first polyester resin being heated. Thereafter, the first polyester resin and the pigment particles are melt-kneaded, the liquid content is removed and evaporated to dryness to obtain a first kneaded product having the first polyester resin and the pigment particles, and then the first kneaded product. A mixture obtained by adding the second polyester resin and, if necessary, an additive such as a charge control agent to the mixture is heated and melt-kneaded to obtain a second kneaded product, and the obtained second kneaded product is cooled. Grinding and classification It is preferred to toner of Te. Here, the first polyester resin and the second polyester resin may be the same or different polyester resins.
[0125]
The paste pigment refers to a state in which the pigment particles are present without passing through the drying step in the pigment particle manufacturing step. In other words, the pigment particles are in a state of approximately 50% by weight based on the total paste pigment in the state of primary particles. The remaining 59 to 95% by weight in the paste pigment is occupied by most volatile liquids along with some dispersants and auxiliaries. The volatile liquid is not particularly limited as long as it is a liquid that evaporates by general heating, but is particularly preferably used in the present invention, and the liquid that is also preferably used ecologically is water.
[0126]
Insoluble pigment particles are pigment particles that are insoluble in a dispersion medium, which is a volatile liquid in the paste pigment, and can be dispersed in the paste pigment. For example, when water is selected as the volatile liquid, all the water-insoluble pigment particles are insoluble pigment particles.
[0127]
The paste pigment preferably contains 5 to 50% by weight, more preferably 5 to 45% by weight, of water-insoluble pigment particles. When the content of the insoluble pigment exceeds 50% by weight, the dispersion efficiency in the polyester resin is low, the kneading temperature must be high, or the kneading time must be set long. Furthermore, a powerful screw or battle structure is indispensable for the kneading apparatus, which easily causes polymer chain breakage.
[0128]
Conversely, when the paste pigment contains less than 5% by weight of insoluble pigment in solid content, in order to obtain the desired pigment content, a large amount of paste pigment must be put into the mixing device and mixed. This is not preferable because the apparatus becomes large. Further, if it is less than 5% by weight, the water removal step in the step after the first kneading must be strengthened and water must be completely blown off, resulting in a large load on the polyester resin. It will be.
[0129]
When the paste pigment and the polyester resin are kneaded or mixed, the ratio of the pigment and the polyester resin in terms of solid content is 10:90 to 50:50, preferably 15:85 to 45:55.
[0130]
When the ratio of the pigment to the polyester resin is smaller than 10% by weight, a large amount of the polyester resin must be charged into the kneading machine with respect to the paste pigment, and the segregation of the pigment is likely to occur in the kneaded product, in order to make this uniform Therefore, it is necessary to set the kneading time longer. In this case, an extra load is applied to the polyester resin, and the characteristics of the polyester resin may change.
[0131]
When the ratio of the pigment to the polyester resin is more than 50% by weight, the transition of the pigment particles in the liquid phase to the polyester resin is difficult to perform smoothly. In addition, the kneading is also performed during the melt kneading after the migration of the pigment particles. It is difficult for the product to show a uniform molten state, and as a result, good dispersibility is difficult to obtain.
[0132]
It is preferable to melt-knead under non-pressurization, because the liquid (for example, water) in the paste pigment attacks the polyester resin under pressure and causes a hydrolysis reaction in part or alters the polyester resin. In some cases, offset resistance may be reduced. Therefore, in the present invention, it is preferable to perform melt kneading of the first polyester resin and the paste pigment under no pressure.
[0133]
Examples of the kneading apparatus include a heating kneader, a single screw extruder, a twin screw extruder, a kneader, and the like, and a heating kneader is particularly preferable.
[0134]
When the charge control agent is contained in the color toner particles, the content of the charge control agent is preferably 3 to 10% by weight, preferably 4 to 8 parts by weight per 100 parts by weight of the binder resin. .
[0135]
When a charge control agent is used, the initial fluctuation of the charge amount is small, and an absolute charge amount necessary for development can be easily obtained. As a result, generation of fog and a decrease in image density are suppressed.
[0136]
Furthermore, if necessary, fatty acid metal salts as lubricants (for example, zinc stearate, aluminum stearate, etc.), fluorine-containing polymer fine powders (for example, polytetrafluoroethylene, polyvinylidene fluoride, etc., and tetrafluoroethylene-vinylidene fluoride) Ride copolymer fine powder) or conductivity imparting agents (tin oxide, zinc oxide) may be added.
[0137]
When the color toner of the present invention is used for a two-component developer, examples of carriers used in combination include metals such as surface oxidized or unoxidized iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, and the like. Alloys or oxides and ferrites can be used.
[0138]
In particular, Mn-Mg'-Fe three-element magnetic ferrite particles formed mainly of manganese, magnesium and iron components are preferred as carrier particles, and Mn-Mg-Fe three-element magnetic ferrite particles are It is particularly preferable when silicon resin is used as the coating resin for the magnetic ferrite particles to have 0.001 to 1% by weight (more preferably 0.005 to 0.5% by weight) of silicon element.
[0139]
The magnetic carrier particles are preferably coated with a resin, and the resin is preferably a silicone resin. In particular, the nitrogen-containing silicone resin or the modified silicone resin produced by the reaction of the nitrogen-containing silane coupling agent and the silicone resin is capable of imparting a negative triboelectric charge to the color toner of the present invention, environmental stability, carrier This is preferable in terms of suppression of surface contamination.
[0140]
The magnetic carrier preferably has an average particle diameter of 15 to 50 μm (more preferably 25 to 45 μm) in relation to the weight average particle diameter of the color toner.
[0141]
The average particle size and particle size distribution of the magnetic carrier are determined by combining a laser diffraction particle size distribution measuring device HELOS (manufactured by JEOL) with a dry dispersion unit RODOS (manufactured by JEOL), a lens focal length of 200 mm, and a dispersion pressure of 3.0 bar. , Measuring the measurement range of 1-2 seconds, dividing the range of particle size 0.5μm to 350.0μm into 31 channels as shown in Table 1 below, and measuring 50% particle size (median diameter) of volume distribution While calculating | requiring as an average particle diameter, the volume% of the particle | grains of each particle size range is calculated | required from frequency distribution on a volume basis.
[0142]
[Table 1]

[0143]
The laser diffraction particle size distribution measuring device HELOS used for measuring the particle size distribution is a device that performs measurement using the Franhofer diffraction principle. Briefly explaining this measurement principle, when a laser beam is irradiated onto a measurement particle from a laser light source, a diffraction image is formed on the focal plane of the lens on the opposite side of the laser light source, and this diffraction image is detected by a detector and processed. By doing so, the particle size distribution of the measurement particles is calculated.
[0144]
As a method for preparing the magnetic particles so as to have the above average particle size and specific particle size distribution, for example, classification can be performed by using a sieve. In particular, in order to classify with high accuracy, it is preferable to repeat a plurality of times using a sieve having an appropriate opening. It is also an effective means to use a mesh opening whose shape is controlled by plating or the like.
[0145]
When a two-component developer is prepared by mixing with a color toner, a good result is obtained when the mixing ratio is 2 to 15% by weight, preferably 4 to 13% by weight, as the toner concentration in the developer. Is obtained. If the toner concentration is less than 2%, the image density tends to be low, and if it exceeds 15% by weight, fogging and in-machine scattering tend to increase.
[0146]
Next, methods for measuring various physical properties will be described.
[0147]
(1) Measuring method of particle size distribution and average particle size of color toner or color toner particles
As a measuring device, Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Inc.) is used. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. For example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the volume and the number of toner particles are measured for each channel by using the 100 μm aperture as the aperture. Thus, the toner volume distribution and number distribution are calculated. Then, the weight-based toner weight average particle diameter (D4) obtained from the volume distribution of the toner particles (the median value of each channel is a representative value for each channel) is obtained.
[0148]
As channels, 2.00 to 2.52 μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm; 4.00 to 5.04 μm; 5.04 to 6.35 μm; 6.35 to 8. 00 μm; 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm; 25.40 to 32.00 μm; 13 channels of 32.00-40.30 μm are used.
[0149]
(2) Measuring method of length average particle size of alumina fine powder
The primary particle diameter is obtained by observing fine alumina powder with a transmission electron microscope, measuring 100 particle diameters of 0.001 μm or more in the visual field, and determining the length average particle diameter. The dispersed particle size of the alumina fine powder on the toner particles is observed with a scanning electron microscope, 100 alumina fine powders in the visual field are qualitatively measured with XMA, and the particle size is measured to obtain the average particle size.
[0150]
(3) Measuring method of hydrophobization degree of alumina fine powder
The methanol titration test is an experimental test for confirming the degree of hydrophobicity of alumina fine powder having a hydrophobized surface.
[0151]
The “methanol titration test” for evaluating the degree of hydrophobicity of the treated alumina fine powder is performed as follows. 0.2 g of test alumina fine powder is added to 50 ml of water in a container. Methanol is titrated from the burette until the entire amount of fine alumina powder is wet. At this time, the solution in the container is constantly stirred with a magnetic stirrer. The end point is observed by suspending the total amount of fine alumina powder in the liquid, and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.
[0152]
(4) Method for measuring BET specific surface area
The actual measurement of the BET of the fine alumina powder is performed as follows.
[0153]
The BET specific surface area is determined by the BET multipoint method using a fully automatic gas adsorption amount measuring device: Autosorb 1 manufactured by Yuasa Ionics Co., Ltd., using nitrogen as the adsorption gas. As sample pretreatment, deaeration is performed at a temperature of 50 ° C. for 10 hours.
[0154]
(5) Crystal structure analysis method
In the present invention, the crystal structure analysis of the alumina fine powder is performed as follows.
[0155]
The X-ray crystal structure analysis is obtained from an X-ray diffraction spectrum using the Kα ray of the characteristic X-ray of Cu as a radiation source. As a measuring machine, for example, a powerful fully automatic X-ray diffractometer MXp¹⁸(McScience) can be used.
[0156]
When alumina has a clear crystal structure, that is, α type alumina, a sharp peak is observed at 2θ (deg) of 20 to 70, and when it is γ type alumina, how many broad peaks are present. Is observed. As an example, FIG. 3 and FIG. 4 show typical α-type and γ-type diffraction peaks.
[0157]
(6) Measurement of toner rheological properties
The toner is pressure-molded into a disk-shaped sample having a diameter of about 25 mm and a thickness of about 2 to 3 mm. Next, it sets to a parallel plate, and it heats up gradually within the temperature range of 50-200 degreeC, and performs temperature dispersion measurement. The temperature rising rate was 2 ° C./min. The angular frequency (ω) is fixed at 6.28 rad / sec, and the distortion rate is automatic. Take the temperature on the horizontal axis and the storage modulus (G ') on the vertical axis, and read the value at each temperature. For the measurement, for example, RDA-II (manufactured by Rheometrics) is used.
[0158]
(7) GPC measurement method of polyester resin or polyester resin constituting color toner
Mn, Mw and Mw / Mn of the polyester resin are measured by gel permeation chromatography (GPC). The column is stabilized in a 40 ° C. heat chamber. Tetrahydrofuran (THF) as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml / min, and 100 μl of THF test solvent is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, a molecular weight of 10 manufactured by Tosoh Corporation or Showa Denko KK is 10² -10⁷ It is appropriate to use a standard polystyrene sample of about 10 points. An R1 (refractive index) detector is used as the detector. As the column, it is preferable to use a combination of a plurality of commercially available polystyrene gel columns.
[0159]
For example, a combination of shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko KK, or TSKgel G1000H (H_XL), G2000H (H_XL), G3000H (H_XL), G4000H (H_XL), G5000H (H_XL), G6000H (H_XL), G7000H (H_XL), A combination of TSK guard column.
[0160]
For example, the sample is prepared as follows.
[0161]
Place the sample in THF and let stand for several hours, then shake well and mix well with THF (until the sample is no longer united) and let stand for more than 12 hours. At this time, the standing time in THF is set to be 24 hours or longer. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5 manufactured by Tosoh Corp., Excro Disc 25CR, Gelman, Science Japan Corp., etc. can be used) is passed. A sample of GPC. The sample temperature is adjusted so that the resin component is 0.5 to 5 mg / ml.
[0162]
A preferred specific example of an image forming apparatus for carrying out an image forming method having a double-side fixing process of the present invention will be described below with reference to FIG.
[0163]
The image forming apparatus shown in FIG. 1 includes a lower digital color image printer unit (hereinafter simply referred to as “printer unit”) I and the above-described digital color image reader unit (hereinafter simply referred to as “reader unit”) II. For example, an image is formed on the recording material P by the printer unit I based on the image of the document D read by the reader unit II.
[0164]
Hereinafter, the configuration of the printer unit I and then the configuration of the reader unit II will be described.
[0165]
The printer unit I includes a photosensitive drum 1 as an electrostatic charge image carrier that is rotationally driven in the direction of arrow R1. Around the photosensitive drum 1, the primary charger (charging means) 2, the exposure means 3, the developing device (developing means) 4, the transfer device 5, the cleaning device 6, the pre-exposure lamp 7 and the like are sequentially arranged along the rotation direction. Is arranged. Below the transfer device 5 (that is, the lower half of the printer unit I), a feeding / conveying unit 8 for the recording material P is disposed. Further, a separation unit 9 is installed above the transfer device 5, and the separation unit 9 is also provided. On the downstream side (downstream side in the conveyance direction of the recording material P), a heating and pressure fixing device 10 and a paper discharge unit 11 are arranged.
[0166]
The photosensitive drum 1 includes an aluminum drum-shaped substrate 1a and an OPC (organic optical semiconductor) photosensitive member 1b covering the surface thereof, and a predetermined process speed (in the direction of arrow R1) by a driving unit (not shown). (Circumferential speed).
[0167]
The primary charger 2 is disposed in a shield 2a having an opening at a portion facing the photosensitive drum 1, a discharge wire 2b disposed in parallel to the bus of the photosensitive drum 1 inside the shield 2a, and an opening of the shield 2a. It is a corona charger having a grid 2c for regulating the charging potential. The primary charger 2 is applied with a charging bias by a power source (not shown), thereby uniformly charging the surface of the photosensitive drum 1 to a predetermined polarity and a predetermined potential.
[0168]
The exposure unit 3 includes a laser output unit (not shown) that emits laser light based on an image signal from the reader unit II described later, a polygon mirror 3a that reflects the laser light, a lens 3b, and a mirror 3c. . The exposure unit 3 is configured to expose the photosensitive drum 1 by irradiating the surface of the photosensitive drum 1 with the laser light, and to remove an electric charge of the exposed portion to form an electrostatic latent image. In this embodiment, the electrostatic latent image formed on the surface of the photosensitive drum 1 is separated into four colors, yellow, cyan, magenta, and black, based on the image of the document, and the electrostatic latent image corresponding to each color is displayed. Images are formed sequentially.
[0169]
The developing device 4 includes developing devices 4Y and 4C that store toners (developers) of yellow toner, cyan toner, magenta toner, and black toner in order from the upstream side along the rotation direction of the photosensitive drum 1 (arrow R1 direction). 4M, 4Bk. Each of the developing devices 4Y, 4C, 4M, and 4Bk has a developing sleeve 4a that carries a developer having toner for developing the electrostatic image formed on the surface of the photosensitive drum 1, and A developing device of a predetermined color to be used for development is arranged at a developing position that is alternatively close to the surface of the photosensitive drum 1 by an eccentric cam 4b. The developer toner carried on the developing sleeve 4a develops the electrostatic image and forms a visible toner image (visible image). The three color developing devices other than the developing device provided for development are retracted from the development position.
[0170]
The transfer device 5 includes a transfer drum (transfer material carrier) 5a that carries a transfer material P on its surface, a transfer charger (transfer charging means) 5b that transfers the toner image on the photosensitive drum 1 to the transfer material P, and a transfer material P. Has a suction charging device 5c for adsorbing the toner to the transfer drum 5a and a suction roller 5d, an inner charging device 5e, and an outer charging device 5f opposite to each other, and is supported by the shaft so as to be rotationally driven in the direction of arrow R5. A transfer material carrying sheet 5g made of a dielectric material is integrally stretched in a cylindrical shape in the peripheral surface opening area of the drum 5a. The transfer material carrying sheet 5g uses a dielectric sheet such as a polycarbonate film. The transfer device 5 is configured to adsorb and carry the transfer material P on the surface of the transfer drum 5a.
[0171]
The cleaning device 6 includes a cleaning blade 6 a that scrapes off residual toner that is not transferred to the transfer material P and remains on the surface of the photosensitive drum 1, and a cleaning container 6 b that collects the scraped toner.
[0172]
The pre-exposure lamp 7 is disposed adjacent to the upstream side of the primary charger 2 and removes unnecessary charges on the surface of the photosensitive drum 1 cleaned by the cleaner 6.
[0173]
The paper feeding / conveying unit 8 includes a plurality of paper feeding cassettes 8a for stacking and storing transfer materials P of different sizes, a paper feeding roller 8b for feeding the transfer material P in the paper feeding cassette 8a, a number of conveying rollers, and a resist. A transfer material P having a roller 8c and the like and having a predetermined size is supplied to the transfer drum 5a.
[0174]
The separating unit 9 includes a separation charger 9a, a separation claw 9b, a separation push-up roller 9c, and the like for separating the transfer material P after the toner image is transferred from the transfer drum 5a.
[0175]
The heat and pressure fixing device 10 includes a fixing roller 10a having a heater inside, and a pressure roller 10b disposed below the fixing roller 10a and pressing the transfer material P against the fixing roller 10a.
[0176]
The paper discharge unit 11 includes a conveyance path switching guide 11a, a discharge roller 11b, a paper discharge tray 11c, and the like disposed on the downstream side of the heat and pressure fixing device 10. Also, below the transport path switching guide 11a, a transport vertical path 11d, a reverse path 11e, a stacking member 11f, an intermediate tray 11g, and a transport roller are used to form an image on both sides of one transfer material P. 11h, 11i, a reverse roller 11j, and the like are disposed.
[0177]
In addition, a potential sensor S for detecting a charging potential on the surface of the photosensitive drum is provided between the primary charger 2 and the developing device 4 around the photosensitive drum 1.₁ However, a density sensor S that detects the density of the toner image on the photosensitive drum 1 is provided between the developing device 4 and the transfer drum 5a.₂ Are arranged.
[0178]
Next, the reader unit II will be described. The reader unit II disposed above the printer unit I further reflects the reflected light from the original D, the original table glass 12a on which the original D is placed, the exposure lamp 12b that exposes and scans the image surface of the original D while moving. A plurality of mirrors 12c, a lens 12d that collects the reflected light, a full color sensor 12e that forms a color separation image signal based on the light from the lens 12d, and the like. The color-separated image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown) and sent to the printer unit I described above.
[0179]
Next, the operation of the image forming apparatus having the above configuration will be described. In the following description, it is assumed that four full-color images are formed in the order of yellow, cyan, magenta, and black.
[0180]
The image of the document D placed on the document table glass 12a of the reader unit II is irradiated with an exposure lamp 12b and subjected to color separation. First, a yellow image is read by a full-color sensor 12e, subjected to predetermined processing, and subjected to an image signal. To the printer unit I.
[0181]
In the printer unit I, the photosensitive drum 1 is rotationally driven in the direction of the arrow R1, and the surface is uniformly charged by the primary charger 2. Based on the image signal sent from the reader unit II, laser light is irradiated from the laser output unit of the exposure unit 3, and the charged photosensitive drum 1 surface is exposed with the optical image E through the polygon mirror 3a and the like. To do. Charges are removed from the exposed portion of the surface of the photosensitive drum 1, whereby an electrostatic image corresponding to yellow is formed. In the developing device 4, the yellow developing device 4Y is disposed at a predetermined developing position, and the other developing devices 4C, 4M, and 4Bk are retracted from the developing position. The electrostatic charge image on the photosensitive drum 1 is developed with a yellow toner by the developing device 4Y and is visualized to become a yellow toner image. The yellow toner image on the photosensitive drum 1 is transferred to the transfer material P carried on the transfer drum 5a. As the transfer material P, a transfer material P having a size suitable for an original image is supplied to a transfer drum 5a at a predetermined timing from a predetermined paper feed cassette 8a through a paper feed roller 8b, a transport roller, and a registration roller 8c. It has been done. The transfer material P thus supplied is adsorbed so as to be wound around the surface of the transfer drum 5a and rotated in the direction of the arrow R5, and the yellow toner image on the photosensitive drum 1 is transferred by the transfer charger 5b.
[0182]
On the other hand, after the yellow toner image has been transferred, the toner remaining on the surface of the photosensitive drum 1 is removed by the cleaning device 6, and unnecessary charges are removed by the pre-exposure lamp 7, so that the next image formation starting from primary charging is performed. Provided.
[0183]
Each process from reading of the original image by the reader unit II to transfer of the toner image to the transfer material P on the transfer drum 5a, cleaning of the photosensitive drum 1, and neutralization is performed in colors other than yellow, that is, cyan. The same is true for magenta and black, and toner images of four colors of yellow toner, cyan toner, magenta toner and black toner are transferred onto the transfer material P on the transfer drum 5a so as to overlap.
[0184]
The transfer material P that has received the transfer of the four color toner images is separated from the transfer drum 5a by the separation charger 9a, the separation claw 9b, and the like, and is conveyed to the fixing device 10 with an unfixed toner image carried on the surface. The The transfer material P is heated and pressed by the fixing roller 10a and the pressure roller 10b of the heat and pressure fixing device 10 to melt and fix the color toner image, and a full color image is formed on one surface of the transfer material. The recording material P after fixing is discharged onto the paper discharge tray 11c by the discharge roller 11b.
[0185]
Next, the heat and pressure fixing device 10 will be described with reference to FIG.
[0186]
In FIG. 2, the fixing roller 10a in contact with the color toner image includes, for example, a 1 mm thick HTV (high temperature vulcanization type) silicone rubber layer 32 on an aluminum core 31 and a specific additional type silicone rubber layer 33 on the outside. And has a diameter of 60 mm.
[0187]
On the other hand, the pressure roller 10b is formed to have a diameter of 60 mm, for example, by providing a 1 mm thick HTV and the above-mentioned specific addition type silicone rubber layer 35 having a thickness of 1 mm on an aluminum cored bar 34. .
[0188]
The above-described fixing roller 10a is provided with a transport roller heater 36 as a heat generating means in the core metal 31, and the pressure roller 10b is similarly provided with a heater 37 in the core metal 34 so that both surfaces of the recording material P are provided. Heating from The temperature of the pressure roller 10b is detected by the thermistor 38 in contact with the pressure roller 10b, and the halogen heaters 36 and 37 are controlled by the control device 39 based on the detected temperature, and the fixing roller 10a and the pressure roller 10b are controlled. Both temperatures are controlled to be kept constant at 170 ° C. The fixing roller 10a and the pressure roller 10b are pressurized with a total pressure of about 80 kg by a pressure mechanism (not shown).
[0189]
In FIG. 2, O is an oil application device, C is a cleaning device, and C1 is a cleaning blade for removing oil stains on the pressure roller 10b. The oil application device O applies the dimethyl silicone oil 41 in the oil pan 40 via the oil pumping rollers 50 and 42 and the oil application roller 43 and regulates the oil application amount by the oil application amount adjusting blade 44 and applies it to the fixing roller 10a. To do. The cleaning device C cleans the surface of the fixing roller 10 a by the web 46 that is in contact with the fixing roller 10 a by the abutting roller 45.
[0190]
In the fixing device 10 described above, the transfer material P carrying the unfixed toner image on the surface is nipped and conveyed in the fixing nip between the fixing roller 10a and the pressure roller 10b, and at this time, heated and pressed from both the front and back surfaces. The toner is fixed. At this time, the toner adhering to the fixing roller 10a and the pressure roller 10b is removed by the cleaning device C and the cleaning blade C1, respectively.
[0191]
As described above, the description has been given of the case where a full-color image is formed only on one surface of the transfer material. Next, a method and apparatus for forming this full-color image on both the front and back surfaces of the transfer material will be described with reference to FIG. .
[0192]
When forming a full-color image on both sides of the transfer material P, the heating and pressure fixing device 10 immediately drives the transport material P after being discharged, drives the transport path switching guide 11a, passes through the transport path 11d, and then into the reversal path 11e. Once guided, the reversing roller 11j is reversed so that the rear end of the reversing roller 11j is used as the head, and the retreating roller 11j is retreated in the direction opposite to the fed direction, and is stored in the intermediate tray 11g. Thereafter, the transfer material P having a full color image on one surface of the intermediate tray 11g is sent to the transfer drum 5a, and the color toners of yellow toner, cyan toner and magenta toner are transferred to the other surface again by the above-described image forming process. Further, black toner is transferred. Since the full color image of the transfer material P comes into contact with the transfer drum 5a, the silicone oil adhering to the full color image surface at the time of fixing adheres to the transfer drum 5a, and the transfer process tends to be normally obstructed. Since the oil absorbability is excellent, the amount of silicone oil adhering to the transfer drum 5a is extremely small compared to the conventional case.
[0193]
The transfer material P having an unfixed color toner image on the other surface of the transfer material is separated from the transfer drum 5a and sent to the heat and pressure fixing device 10, and the unfixed color toner image is transferred to the other side of the transfer material. The surface is heated and pressed and fixed, and a full color image is formed on both sides of the transfer material P. At that time, the color toner of the present invention has a specific hydrophobic alumina fine powder externally added to the color toner particles, and has a specific particle size distribution and a specific viscoelastic property. The wrapping of the transfer material P around the fixing roller 10a and the pressure roller 10b is suppressed, and the occurrence of the offset phenomenon can be prevented well.
[0194]
When the color toner of the present invention is used, the transfer material carrying sheet 5g of the transfer drum 5a is extremely less contaminated with silicone oil or the like than in the past, but if necessary, the fur brush 13a, the backup brush 13b, the oil removal roller 14a, and the backup Cleaning is performed by the brush 14b. Such cleaning is performed before or after image formation as necessary, and is performed at any time when a jam (paper jam) occurs.
[0195]
【Example】
Synthesis Example 1 of Hydrophobic Alumina Fine Powder
To 3 liters of 2M ammonium bicarbonate solution, 2 liters of 0.2M ammonium light vane solution was added dropwise at a rate of 0.8 liters per hour while keeping the liquid temperature at 35 ° C., and reacted with vigorous stirring._Four AlCO_Three (OH)₂ Of aluminum ammonium carbonate hydroxide was produced, followed by filtration and drying. The resulting aluminum ammonium carbonate hydroxide fine powder has a BET specific surface area of 280 m.² / G. The fine powder was heat-treated at about 900 ° C. for 2 hours to produce a hydrophilic alumina fine powder. The produced hydrophilic alumina fine powder has a BET specific surface area of 250 m.² / G, the primary particles have a length average particle size of 5 nm, a methanol hydrophobization degree of 0%, and the crystal form was confirmed to be γ-based by X-ray diffraction.
[0196]
Next, after the alumina fine powder is uniformly dispersed in toluene, the alumina particles are not coalesced so that isobutyltrimethoxysilane is 30 parts by weight in solid form with respect to 100 parts by weight of the alumina fine powder. The mixture was added dropwise to cause hydrolysis. Thereafter, after filtration and drying, baking was performed at 180 ° C. for 2 hours, followed by thorough crushing treatment. 1 was obtained. This hydrophobic alumina fine powder no. 1 primary particles have a length average particle diameter of 0.005 μm (5 nm) and a BET specific surface area of 190 m.² / G, and the degree of methanol hydrophobization was 66%.
[0197]
Synthesis example 2 of fine hydrophobic alumina powder
Commercially available aluminum oxide fine powder which is γ-alumina (Nippon Aerosil Co., Ltd., Oxide-C, BET specific surface area 100 m² / G) was subjected to a hydrophobizing treatment in the same manner as in Synthesis Example 1 using 15 parts by weight of isobutyltrimethoxysilane, and a hydrophobic alumina fine powder no. 2 was obtained. The physical properties are shown in Table 2.
[0198]
Synthesis Example 3 of Hydrophobic Alumina Fine Powder
Γ-alumina (BET specific surface area of 149 m) produced by hydrolysis of organoaluminum² / G) was subjected to a hydrophobization degree treatment in the same manner as in Synthesis Example 1 using 15 parts by weight of isobutyltrimethoxysilane to prepare a hydrophobic alumina fine powder No. 3 was obtained. The physical properties are shown in Table 2.
[0199]
Synthesis example 4 of fine hydrophobic alumina powder
NH used in Synthesis Example 1_Four AlCO_Three (OH)₂ Was fired at about 1260 ° C. for about 60 minutes to produce α-alumina fine powder. This alumina fine powder showed a sharp and clear peak in the X-ray diffraction data, and was confirmed to be α-type. The physical properties are shown in Table 2.
[0200]
The α-alumina fine powder was treated in the same manner as in Synthesis Example 1 (however, the amount of the treatment agent was reduced to 10% by weight). 4 was produced. The physical properties are shown in Table 2.
[0201]
Synthesis example of hydrophobic silica fine powder
Commercially available hydrophilic silica fine powder (AEROSIR200 manufactured by Nippon Aerosil Co., Ltd., BET specific surface area 200 m² / G) was subjected to a hydrophobizing treatment in the same manner as in Synthesis Example 1 to obtain hydrophobic silica fine powder. The physical properties are shown in Table 2.
[0202]
Synthesis example of hydrophobic titanium oxide fine powder
Amorphous titanium oxide fine powder produced by oxidizing titanium alkoxide (BET specific surface area 135m² / G) was hydrophobized using 20 parts by weight of isobutyltrimethoxysilane in the same manner as in Synthesis Example 1 to obtain hydrophobic titanium oxide fine powder. The physical properties are shown in Table 2.
[0203]
[Table 2]

[0204]
Production example 1 of polyester resin
[0205]
[Outside 13]

Diol component (E-1) represented by x + y = 2.1 25 mol%
Fumaric acid (HOOC-CH = CH-COOH) 25 mol%
[0206]
The monomer was polycondensed to produce a linear prepolymer having a number average molecular weight (Mn) of 850.
[0207]
Subsequently, the linear prepolymer and the following monomer were mixed and subjected to polycondensation to obtain a non-linear crosslinked polyester resin (1).
[0208]
[Outside 14]

Diol component represented by (x + y = 2.1) 20 mol%
[0209]
[Outside 15]

Diol component represented by (x + y = 2.1) 5 mol%
Fumaric acid 10mol%
Terephthalic acid 10mol%
Trimellitic acid 0.2 mol%
[0210]
The obtained crosslinked polyester resin (1) has a glass transition temperature (Tg) of 59 ° C., a chloroform-insoluble content of 0 wt%, and a number average molecular weight (Mn) of 3200 in GPC as a THF-soluble component. Yes, the main peak (Mp) was 8400, and Mw / Mn was 3.6.
[0211]
The chloroform insoluble content of the polyester resin is a value measured by the following method.
[0212]
1 g of polyester resin is added to 50 ml of chloroform at room temperature, and after stirring, dispersion by ultrasonic waves is performed for 5 minutes. The obtained membrane filter (weight W₁ The chloroform-insoluble matter is filtered off according to g). Weight of membrane filter carrying chloroform insoluble matter after drying membrane filter carrying chloroform insoluble matter and removing chloroform (W₂ g) is measured, and the content of chloroform-insoluble matter is calculated as follows.
[0213]
[Outside 16]

[0214]
Production example 2 of polyester resin
[0215]
[Outside 17]

Diol component represented by (x + y = 2.1) 25 mol%
Fumaric acid 25 mol%
[0216]
The monomer was polycondensed to produce a linear prepolymer having a number average molecular weight (Mn) of 850. Subsequently, the linear prepolymer and the following monomer were mixed and subjected to polycondensation to obtain a crosslinked polyester resin (2).
[0217]
[Outside 18]

Diol component represented by (x + y = 2.1) 10 mol%
[0218]
[Outside 19]

Diol component represented by (x + y = 2.1) 15 mol%
Fumaric acid 10mol%
Terephthalic acid 15mol%
Trimellitic acid 0.3 mol%
[0219]
The obtained non-linear polyester resin (2) has a Tg of 56 ° C., a chloroform insoluble content of 0 wt%, a MPC of THF-soluble component of GPC of 3500, Mp of 9000, Mw / Mn was 3.9.
[0220]
Production example 3 of polyester resin
[0221]
[Outside 20]

Diol component represented by (x + y = 2.1) 30 mol%
Fumaric acid 30mol%
[0222]
The above monomer was polycondensed to obtain a linear prepolymer having Mn of 920. Subsequently, the linear prepolymer and the following monomer were mixed and subjected to polycondensation to obtain a crosslinked polyester resin (3).
[0223]
[Outside 21]

Diol component represented by (x + y = 2.1) 20 mol%
Fumaric acid 10mol%
Terephthalic acid 10mol%
Trimellitic acid 0.3 mol%
[0224]
The obtained crosslinked polyester resin (3) has a Tg of 54 ° C., a chloroform-insoluble content of 0 wt%, a MPC of THF-soluble component of GPC of 3100, Mp of 8000, and Mw / Mn. Was 3.5.
[0225]
Production example 4 of polyester resin
[0226]
[Outside 22]

Diol component represented by (x + y = 2.1) 25 mol%
[0227]
[Outside 23]

Diol component represented by (x + y = 2.1) 25 mol%
Fumaric acid 50mol%
Terephthalic acid 0 mol%
Trimellitic acid 0.1 mol%
[0228]
The said monomer was mixed and the polycondensation reaction was performed and the non-linear crosslinked polyester resin (4) was obtained. The obtained crosslinked polyester resin (4) has a Tg of 49 ° C., a chloroform-insoluble content of 0 wt%, a MPC of 2700, a Mp of 5800, and a Mw / Mn in GPC as a THF-soluble component. Was 2.8.
[0229]
Production example 5 of polyester resin
[0230]
[Outside 24]

Diol component represented by (x + y = 2.1) 35 mol%
[0231]
[Outside 25]

Diol component represented by (x + y = 2.1) 15 mol%
Fumaric acid 35mol%
Terephthalic acid 15mol%
Trimellitic acid 0.3 mol%
[0232]
The above monomers were mixed and subjected to a condensation polymerization reaction to obtain a non-linear cross-linked polyester resin (5). The obtained cross-linked polyester resin had a Tg of 58 ° C., a chloroform-insoluble content of 0 wt%, a MPC of THF of GPC of 3400, Mp of 9200, and Mw / Mn of 8. 0.
[0233]
Production example 6 of polyester resin
[0234]
[Outside 26]

Diol component represented by (x + y = 2.1) 15 mol%
[0235]
[Outside 27]

Diol component represented by (x + y = 2.1) 35 mol%
Terephthalic acid 48mol%
[0236]
The said monomer was mixed and the polycondensation reaction was performed and the linear polyester resin (6) was obtained. The obtained linear polyester resin (6) has a Tg of 68 ° C., a chloroform-insoluble content of 0 wt%, a GPC of a THF-soluble component, Mn of 5800, Mp of 14000, Mw / Mn was 5.2.
[0237]
Production example 7 of polyester resin
[0238]
[Outside 28]

Diol component represented by (x + y = 2.1) 50 mol%
Fumaric acid 15 mol%
Terephthalic acid 35mol%
Trimellitic acid 0.6 mol%
[0239]
The above monomers were mixed and subjected to polycondensation to obtain a non-linear crosslinked polyester resin (7). The obtained crosslinked polyester resin (7) has a Tg of 63 ° C., a chloroform insoluble content of 14.3 wt%, a MPC of THF-soluble component of GPC of 4800, Mp of 13000, Mw / Mn was 19.5.
[0240]
Example 1
-Cross-linked polyester resin (1) 70 parts by weight
・ C. I. Pigment Blue 15: 3 cyan pigment paste 100 parts by weight
(Pigment solid content 30 wt%, moisture 70 wt%)
As the cyan pigment paste, a paste that had not been subjected to a powdering process even after production was used.
[0241]
The above materials were put into a kneader type mixer and gradually heated while being mixed under an open non-pressurized condition. When the temperature reached 90 to 100 ° C., it was confirmed that the cyan pigment particles in the aqueous phase were distributed or transferred to the polyester resin phase, and then the heat-melt kneading was continued for another 30 minutes. After kneading, the separated hot water is discharged from the mixer, and then the temperature of the mixer is raised to 130 ° C., and the polyester resin in which the cyan pigment particles are dispersed is heated and melt-kneaded for about 30 minutes. The particles were dispersed more uniformly and moisture was removed. After kneading, the kneaded product was cooled, and the cooled kneaded product was pulverized to obtain cyan pigment-containing polyester resin particles having a particle size of 1 mm or less.
[0242]
・ Cyan pigment-containing polyester resin particles 16.7 parts by weight
(Cyan pigment content 30% by weight)
・ Crosslinked polyester resin 88.3 parts by weight
・ 4 parts by weight of negative charge control agent
(Aluminum compound of di-tertiary butylsalicylic acid)
[0243]
The above materials were sufficiently premixed with a Henschel mixer, and the resulting mixture was melt-kneaded with a twin screw extruder at a set temperature of 100 ° C.
[0244]
The discharged melt-kneaded product had a temperature of 137 to 139 ° C. The melt-kneaded product was cooled and then roughly pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized with an air jet type pulverizer. Further, the finely pulverized product thus obtained was rigorously removed at the same time with a multi-division classifier, and the cyan toner particle No. 1 was obtained. The obtained cyan toner particle No. No. 1 has a weight average particle size of 7.2 μm, a number average particle size of 5.9 μm, 14% by number of toner particles having a particle size of 4 μm or less, and 34 toner particles having a particle size of 5.04 μm or less. The toner particles having a particle diameter of 8 μm or more were 29% by volume, and the toner particles having a particle diameter of 10.08 μm or more were 3.5% by volume.
[0245]
Cyan toner particle No. 1 to 100 parts by weight of hydrophobic alumina fine powder No. 1 1.5 parts by weight of 1 and strontium titanate powder (length average particle size 1.2 μm, BET specific surface area 2.3 m² / G) is mixed with 0.5 part by weight of cyan toner no. 1 was prepared. Cyan toner particle No. 1 and cyan toner no. Table 3 and Table 4 show the physical properties of No. 1.
[0246]
Cyan toner no. 95 parts by weight of magnetic Mn—Mg—Fe ferrite carrier particles having an average particle diameter of 38 μm coated with 5 parts by weight of 1 and about 0.5% by weight of a resin obtained by reacting a nitrogen-containing cyan coupling agent with a silicone resin A two-component developer for developing a magnetic brush was prepared by mixing with a part.
[0247]
This two-component developer was introduced into a modified machine of a commercially available plain paper full-color copying machine (Color Laser Copier 800), and a copying test was conducted using plain paper as a transfer material. At this time, the fixing roller has a 2 mm thick HTV (high temperature vulcanization type) silicone rubber layer on a 5 mm thick aluminum core, a 50 μm thick fluororubber layer on the outside, and a 230 μm thick on the outside. An additional type silicone rubber layer having a diameter of 60 mm is used, and the pressure roller is an HTV silicone rubber layer having a thickness of 1.5 mm on an aluminum core metal having a thickness of 5 mm. A fluororubber layer having an addition type silicone rubber layer having a thickness of 200 μm on the outside was used.
[0248]
The fixing temperature was 155 ° C., the fixing speed was 200 mm / sec, and the cyan toner image was fixed on plain paper while applying dimethyl silicone oil to the fixing roller.
[0249]
Coloring power D of cyan color toner_0.5In order to measure the amount of cyan color toner M / S on plain paper, 0.5 mg / cm²The prepared image was fixed to form a cyan color image having a glossiness of 15%, and the image density was measured using an X-Rite 404A color reflection densitometer manufactured by X-Rite. The result is D_0.5Was 1.42.
[0250]
For measurement of gloss (glossiness), a VG-10 glossiness meter manufactured by Nippon Denshoku Co., Ltd. was used. For measurement, first set the voltage to 6 V with a constant voltage device, then adjust the light projection angle and light reception angle to 60 degrees, use the zero point adjustment and the standard plate, and set the white paper on the sample stage after standard setting. The fixed image was measured on the sheet, and the numerical value shown on the marking portion was read in%.
[0251]
When an image was printed under an environment of normal temperature and humidity (23 ° C., 60% RH) at a contrast potential of 300 V, the color tone of the image was excellent in saturation and vivid. A cyan image faithful to the original image without fogging was obtained even with a durability of 60,000 sheets. The transportability of cyan color toner in the full-color copying machine was good, the density of cyan color toner was well detected, and the image density was stable. Further, when a cyan toner image was transferred to an OHP film and the fixed image was translucent with an overhead projector, a clear cyan image having excellent translucency was projected on the screen.
[0252]
A good cyan color image was obtained even in a low temperature and low humidity (15 ° C., 10% RH) environment and a high temperature and high humidity (32.5 ° C., 85% RH) environment, and the environmental stability was excellent.
[0253]
Next, using a color leather copier 800 remodeling machine, double-sided fixing was performed to form solid images on both sides of plain paper.
[0254]
Cyan toner no. No. 1 has a high coloring power and can set a small amount of toner on plain paper, so that usually little curling of plain paper after fixing once can be seen, and therefore the transportability of plain paper in a copying machine. Was also good. Attempts were made to endure a large number of 10,000 double-sided fixed images of a solid image having a fixed image density of 1.7 continuously, but no jamming (paper jam) was observed.
[0255]
In addition, on the surface of the obtained image, there was no image defect due to oil such as uneven application of silicone oil, uneven stripe, etc. 1 was found to be excellent in silicone oil adsorption.
[0256]
Further, no silicone oil was detected from the surface of the photosensitive drum or transfer drum after the endurance of a large number of sheets, and it was determined that there was no or very little oil transfer from the fixed image surface.
[0257]
Comparative Example 1
Cyan toner particle No. No. 1 was externally added with 1.5 parts by weight of the hydrophobic silica fine powder shown in Table 2, and comparative cyan toner No. 1 was added. 1 was prepared. Comparative cyan toner No. The physical properties of 1 are shown in Tables 3 and 4. Comparative cyan toner No. 1 was used to prepare a two-component developer in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.
[0258]
Comparative Example 2
Cyan toner particle No. No. 1 was externally added with only 1.5 parts by weight of hydrophobic titanium oxide fine powder shown in Table 2, and comparative cyan toner No. 1 was added. 2 was prepared. Comparative cyan toner No. The physical properties of 2 are shown in Tables 3 and 4. Comparative cyan toner No. 2 was used to prepare a two-component developer in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.
[0259]
Comparative Example 3
Cyan toner particle No. 1, 100 parts by weight of hydrophobic silica fine powder shown in Table 2 and strontium titanate powder (length average particle size 1.2 μm, BET specific surface area 2.3 m)² / G) is added as a comparative cyan toner no. 3 was prepared. Comparative cyan toner No. The physical properties of 3 are shown in Tables 3 and 4. Comparative cyan toner No. 3 was used to prepare a two-component developer in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.
[0260]
Comparative Example 4
Cyan toner particle No. 1, 100 parts by weight of hydrophobic titanium oxide fine powder shown in Table 2 and strontium titanate powder (length average particle size 1.2 μm, BET specific surface area 2.3 m)² A comparative cyan toner no. 4 was prepared. Comparative cyan toner No. Table 3 and Table 4 show the physical properties of No. 4. Comparative cyan toner No. 2 was used to prepare a two-component developer in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.
[0261]
Comparative Examples 5 to 8
Example 1 except that instead of the crosslinked polyester resin (1), a crosslinked polyester resin (4), a crosslinked polyester resin (5), a linear polyester resin (6) or a crosslinked polyester resin (7) is used. Similarly, comparative cyan toner particles Nos 1 to 4 were obtained.
[0262]
Comparative cyan toner particle No. Comparative cyan toners Nos 5 to 8 were prepared by externally adding 1.5 parts by weight of hydrophobic silica fine powder shown in Table 2 to 100 parts by weight of 1 to 4. Tables 3 and 4 show the physical properties of comparative cyan toner particles Nos 1 to 4 and comparative cyan toners Nos 5 to 8.
[0263]
Two-component developers were prepared in the same manner as in Example 1 using comparative cyan toners Nos 5 to 8, and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.
[0264]
Comparative Examples 9 to 12
Comparative cyan toner Nos 9 to 12 were prepared by externally adding 1.5 parts by weight of hydrophobic titanium oxide fine powder shown in Table 2 to 100 parts by weight of each of comparative cyan toner particles Nos 1 to 4. Table 4 shows the physical properties of comparative cyan toners Nos 9 to 12.
[0265]
Two-component developers were prepared in the same manner as in Example 1 using comparative cyan toners Nos 9 to 12, and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.
[0266]
Comparative Example 13
Cross-linked polyester resin (4) 100 parts by weight
Cyan colorant (CI Pigment Blue 15: 3) 5 parts by weight
4 parts by weight of negative charge control agent
(Aluminum compound of jettery butylsalicylic acid)
[0267]
Using the above materials, the same as in Example 1, melt kneading, cooling, pulverizing and classifying were performed, and comparative cyan toner particle No. No. 5 was prepared and Comparative Cyan Toner No. 13 was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.
[0268]
Comparative Examples 14 to 16
Comparative cyan toner particles Nos6 in the same manner as in Comparative Example 13 except that the crosslinked polyester resin (5), the linear polyester resin (6) or the crosslinked polyester resin (7) is used in place of the crosslinked polyester resin (4). To 8 were prepared, comparative cyan toners Nos 14 to 16 were prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The results are shown in Table 5.
[0269]
[Table 3]

[0270]
[Table 4]

[0271]
[Table 5]

[0272]
Evaluation of translucency of OHP fixed image
A (good): Excellent transparency, no light / dark unevenness, and excellent color reproducibility.
B (Normal): There is slight unevenness in brightness but there is no practical problem.
C (Poor): There is light and dark unevenness and color reproducibility is inferior.
[0273]
Evaluation of the presence or absence of contamination by silicone oil during double-sided fixing
A: The transfer material carrying sheet of the transfer drum is not contaminated with silicone oil.
B: The transfer material carrying sheet of the transfer drum is slightly contaminated with silicone oil, but there is substantially no influence on the transfer process.
C: Contamination due to silicone oil is observed on the transfer material carrying sheet of the transfer drum, which adversely affects the transfer process.
[0274]
Degree of curling of transfer material during single-sided fixing
The following three stages were evaluated visually.
A: There is almost no curling, and no problem occurs in the transportability of plain paper.
B: Some curling occurs, but there is no practical problem with the transportability of plain paper.
C: Curling occurs, and a problem may occur when an image is formed on the back side of plain paper.
[0275]
Photosensitive drum surface after endurance
After the endurance of 60,000 sheets, the surface of the photosensitive drum was visually observed and evaluated in the following three stages.
A: There is substantially no difference from the initial durability.
B: Filming with toner is partly on the surface of the photosensitive drum, but there is no practical problem.
C: Filming with toner is present on the surface of the photosensitive drum, and defects may occur on the image.
[0276]
Highlight section reproducibility
The fixed images at the initial stage of durability and after the endurance of 60,000 sheets were visually evaluated in three stages.
A: Fine line reproducibility is good, and the hearton portion (highlight portion) of the photographic image is faithfully reproduced.
B: Slightly inferior, but within practical level.
C: Inferior to smoothness and conspicuous.
[0277]
Evaluation of fog
The fog is measured with a reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) for the whiteness of the white background of the image after the initial durability and after the durability, and the fog density ( %) Was calculated and evaluated. The evaluation criteria are shown below.
A: Very good (less than 1.0%)
B: Good (1.0% or more to less than 2.0%)
C: Poor (2.0% or more)
[0278]
Comparative Examples 17 to 21
Comparative cyan toner particles Nos. 9 to 13 were prepared in the same manner as in Example 1 except that the pulverization conditions and classification conditions were changed. 17 to 21 were prepared and evaluated in the same manner as in Example 1. Table 6 shows the physical properties of the comparative cyan toner particles Nos 9 to 13, and the comparative cyan toner no. The physical properties of 17 to 21 are shown in Table 7, and the evaluation results are shown in Table 8.
[0279]
Examples 2 to 3
Cyan toner particles Nos 2 and 3 were prepared in the same manner as in Example 1 except that the crosslinked polyester resin (2) or (3) was used instead of the crosslinked polyester resin (1). Cyan toners Nos 2 and 3 were prepared and evaluated in the same manner as in Example 1. Table 6 shows the physical properties of the cyan toner particles, Table 7 shows the physical properties of the cyan toners Nos 2 and 3, and Table 8 shows the evaluation results.
[0280]
Examples 4 to 6
Hydrophobic alumina fine powder No. Cyan toners Nos 4 to 6 were prepared in the same manner as in Example 1 except that hydrophobic alumina fine powders Nos 2 to 4 were used instead of 1, and evaluated in the same manner as in Example 1. Table 7 shows the physical properties of cyan toners Nos 4 to 6, and Table 8 shows the evaluation results.
[0281]
[Table 6]

[0282]
[Table 7]

[0283]
[Table 8]

[0284]
Example 7
-Crosslinked polyester resin (1) 58.3 parts by weight
・ C. I. 100 parts by weight of pigment red 122 magenta pigment paste
(Pigment solid content 25 wt%, moisture 75 wt%)
[0285]
As the magenta pigment paste, a paste that has not been subjected to a powdering process once after production was used.
[0286]
Using the above materials, magenta pigment-containing polyester resin particles were obtained in the same manner as in Example 1.
・ Magenta pigment-containing polyester resin particles 20 parts by weight
(Magenta pigment content 30% by weight)
・ 86 parts by weight of crosslinked polyester resin (1)
・ 4 parts by weight of negative charge control agent
(Aluminum compound of jettery butylsalicylic acid)
[0287]
Using the above materials, the same as in Example 1, the magenta toner particle No. 1 was obtained. The obtained magenta toner particle No. 1 to 100 parts by weight of hydrophobic alumina fine powder No. 1 1.5 parts by weight of 1 and strontium titanate powder (length average particle size 1.2 μm, BET specific surface area 2.3 m² / G) is mixed with 0.5 part by weight of magenta toner no. 1 was prepared. Magenta toner particle No. 1 and magenta toner no. The physical properties of 1 are shown in Tables 9 and 10.
[0288]
95 parts by weight of magnetic Mn—Mg—Fe ferrite carrier particles having an average particle diameter of 38 μm coated with 5 parts by weight of magenta toner and about 1% by weight of a resin obtained by reacting a nitrogen-containing cyan coupling agent with a silicone resin Were mixed to prepare a two-component developer for magnetic brush development.
[0289]
Using a two-component developer, an image output test was conducted in the same manner as in Example 1. Magenta toner coloring power D_0.5 Was 1.32.
[0290]
Even in the 30,000-sheet durability test, the image density was stable, the highlight portion was excellent in reproducibility, and the OHP image was excellent in transparency.
[0291]
Also, good results were obtained in a double-sided durability test of 10,000 sheets. The evaluation results are shown in Table 11.
[0292]
Examples 8 and 9
Magenta toner particles Nos 2 and 3 were prepared in the same manner as in Example 7 except that the crosslinked polyester resin (2) or (3) was used instead of the crosslinked polyester resin (1). Magenta toners Nos 2 and 3 were prepared and evaluated in the same manner as in Example 7. Table 9 shows the physical properties of the magenta toner particles Nos2 and 3, Table 10 shows the physical properties of the magenta toner Nos2 and 3, and Table 11 shows the evaluation results.
[0293]
Comparative Example 22
Magenta toner particle No. No. 1 was externally added with only 1.5 parts by weight of hydrophobic silica fine powder shown in Table 2, and comparative magenta toner No. 1 was added. 1 was prepared. Comparative Magenta Toner No. The physical properties of 1 are shown in Tables 9 and 10. Comparative Magenta Toner No. 1 was used to prepare a two-component developer in the same manner as in Example 7 and evaluated in the same manner as in Example 7. The evaluation results are shown in Table 11.
[0294]
Comparative Example 23
Magenta toner particle No. No. 1 was externally added with only 1.5 parts by weight of hydrophobic titanium oxide fine powder shown in Table 2, and comparative magenta toner no. 2 was prepared. Comparative Magenta Toner No. The physical properties of 2 are shown in Tables 9 and 10. Comparative Magenta Toner No. 2 was used to prepare a two-component developer in the same manner as in Example 7 and evaluated in the same manner as in Example 7. The evaluation results are shown in Table 11.
[0295]
Comparative Examples 24 to 27
Example 4 except that instead of the crosslinked polyester resin (1), a crosslinked polyester resin (4), a crosslinked polyester resin (5), a linear polyester resin (6) or a crosslinked polyester resin (7) is used. Similarly, comparative magenta toner particles Nos 1 to 4 were obtained.
[0296]
Comparative magenta toner Nos 3 to 6 were prepared by externally adding 1.5 parts by weight of hydrophobic silica fine powder shown in Table 2 to 100 parts by weight of comparative magenta toner particles Nos 1 to 4. Tables 9 and 10 show the physical properties of the comparative magenta toner particles Nos 1 to 4 and the comparative magenta toner Nos 3 to 6.
[0297]
Two-component developers were prepared in the same manner as in Example 7 using comparative magenta toners Nos 3 to 6, and evaluated in the same manner as in Example 4. The evaluation results are shown in Table 11.
[0298]
Comparative Examples 28 to 31
Comparative magenta toners Nos 7 to 10 were prepared by externally adding 1.5 parts by weight of hydrophobic titanium oxide fine powder shown in Table 2 to 100 parts by weight of each of comparative magenta toner particles Nos 1 to 4. Tables 9 and 10 show the physical properties of comparative magenta toners Nos 7 to 10.
[0299]
Two-component developers were prepared in the same manner as in Example 7 using comparative magenta toners Nos 7 to 10, and evaluated in the same manner as in Example 7. The evaluation results are shown in Table 11.
[0300]
Comparative Example 32
-Cross-linked polyester resin (4) 100 parts by weight
・ Magenta colorant (CI Pigment Red 122) 6 parts by weight
・ 4 parts by weight of negative charge control agent
(Aluminum compound of jettery butylsalicylic acid)
[0301]
Using the above materials, the kneading, cooling, pulverization and classification were carried out in the same manner as in Example 4, and the comparative magenta toner particle No. No. 5 was prepared and Comparative Magenta Toner No. 5 was prepared in the same manner as in Example 7. 11 was prepared and evaluated in the same manner as in Example 7. The evaluation results are shown in Table 11.
[0302]
[Table 9]

[0303]
[Table 10]

[0304]
[Table 11]

[0305]
Example 10
-Cross-linked polyester resin (1) 100 parts by weight
・ C. I. 100 parts by weight of Pigment Yellow 17 yellow pigment paste
(Pigment solid content 20 wt%, moisture 80 wt%)
[0306]
The yellow pigment paste used was not subjected to a powdering process even after production.
[0307]
Using the above materials, yellow pigment-containing polyester resin particles were obtained in the same manner as in Example 1.
[0308]
・ Yellow pigment-containing polyester resin particles 20 parts by weight
(Yellow pigment content 20% by weight)
-Cross-linked polyester resin (1) 84 parts by weight
・ 4 parts by weight of negative charge control agent
(Aluminum compound of jettery butylsalicylic acid)
[0309]
Using the above materials, yellow toner particle No. 1 was obtained. The resulting yellow toner particle No. 1 to 100 parts by weight of hydrophobic alumina fine powder No. 1 1.5 parts by weight of 1 and strontium titanate powder (length average particle size 1.2 μm, BET specific surface area 2.3 m² / G) is mixed with 0.5 part by weight of yellow toner no. 1 was prepared. Yellow toner particle No. 1 and yellow toner no. The physical properties of 1 are shown in Tables 12 and 13.
[0310]
Yellow toner No. 1, 95 parts by weight of magnetic Mn—Mg—Fe ferrite carrier particles having an average particle diameter of 38 μm and coated with about 1% by weight of a resin obtained by reacting a nitrogen-containing cyan coupling agent and a silicone resin Were mixed to prepare a two-component developer for magnetic brush development.
[0311]
Using a two-component developer, an image output test was conducted in the same manner as in Example 1. Yellow toner coloring power D_0.5 Was 1.45.
[0312]
Even in the 30,000-sheet durability test, the image density was stable, the highlight portion was excellent in reproducibility, and the OHP image was excellent in transparency.
[0313]
Furthermore, good results were also shown in a double-sided durability test of 10,000 sheets. The evaluation results are shown in Table 14.
[0314]
Examples 11 and 12
Yellow toner particles Nos 2 and 3 were prepared in the same manner as in Example 10 except that the crosslinked polyester resin (2) or (3) was used instead of the crosslinked polyester resin (1). Yellow toners Nos 2 and 3 were prepared and evaluated in the same manner as in Example 10. The physical properties of the yellow toner particles Nos 2 and 3 are shown in Table 12, the physical properties of the yellow toner Nos 2 and 3 are shown in Table 13, and the evaluation results are shown in Table 14.
[0315]
Comparative Example 33
Yellow toner particle No. No. 1 was added to 1.5 parts by weight of hydrophobic silica fine powder shown in Table 2 and 100% by weight of Comparative Yellow Toner No. 1 was externally added. 1 was prepared. Comparative Yellow Toner No. The physical properties of 1 are shown in Tables 12 and 13. Comparative Yellow Toner No. 1 was used to prepare a two-component developer in the same manner as in Example 10 and evaluated in the same manner as in Example 10. The evaluation results are shown in Table 14.
[0316]
Comparative Example 34
Yellow toner particle No. No. 1 was added to 1.5 parts by weight of hydrophobic titanium oxide fine powder shown in Table 2 and 100 parts by weight of Comparative No. 1 2 was prepared. Comparative Yellow Toner No. The physical properties of 2 are shown in Tables 12 and 13. Comparative Yellow Toner No. 2 was used in the same manner as in Example 10 to prepare a two-component developer and evaluated in the same manner as in Example 10. The evaluation results are shown in Table 14.
[0317]
Comparative Examples 35 to 38
Example 10 except that instead of the crosslinked polyester resin (1), a crosslinked polyester resin (4), a crosslinked polyester resin (5), a linear polyester resin (6) or a crosslinked polyester resin (7) is used. Similarly, comparative yellow toner particles Nos 1 to 4 were obtained.
[0318]
Comparative yellow toner Nos 3 to 6 were prepared by externally adding 1.5 parts by weight of hydrophobic silica fine powder shown in Table 2 to 100 parts by weight of each of comparative yellow toner particles Nos 1 to 4. Tables 12 and 13 show the physical properties of the comparative yellow toner particles Nos 1 to 4 and the comparative yellow toner Nos 3 to 6.
[0319]
Two-component developers were prepared in the same manner as in Example 10 using comparative yellow toners Nos 3 to 6, and evaluated in the same manner as in Example 4. The evaluation results are shown in Table 14.
[0320]
Comparative Examples 39 to 42
Comparative yellow toners Nos 7 to 10 were prepared by externally adding 1.5 parts by weight of hydrophobic titanium oxide fine powder shown in Table 2 to 100 parts by weight of each of the comparative yellow toner particles Nos 1 to 4. Tables 13 and 14 show the physical properties of comparative yellow toners Nos 7 to 10.
[0321]
Two-component developers were prepared in the same manner as in Example 10 using comparative yellow toners Nos 7 to 10, and evaluated in the same manner as in Example 10. The evaluation results are shown in Table 14.
[0322]
Comparative Example 43
-Cross-linked polyester resin (4) 100 parts by weight
-Magenta colorant (CI Pigment Yellow 17) 4 parts by weight
・ 4 parts by weight of negative charge control agent
(Aluminum compound of jettery butylsalicylic acid)
[0323]
The above materials were used in the same manner as in Example 10 to perform melt-kneading, cooling, pulverization and classification, and comparative yellow toner particles No. No. 5 and Comparative Yellow Toner No. 11 was prepared and evaluated in the same manner as in Example 10. The evaluation results are shown in Table 14.
[0324]
[Table 12]

[0325]
[Table 13]

[0326]
[Table 14]

[0327]
Example 13
The cyan toner No. 1 of Example 1. A two-component developer having a magenta toner No. 1 of Example 7. 1 and a yellow toner No. 1 of Example 10. Using a two-component developer having No. 1, a full-color image was tested in the full-color mode using the full-color copying machine used in Example 1, and full-color images were formed on both sides of plain paper by double-sided fixing. The formed full-color image is superior in image quality compared to the original image, and even when many sheets are used, the transfer material carrying sheet of the transfer drum is not contaminated with silicone oil, and plain paper curls are generated. A small amount of plain paper having a fixed image in the apparatus was smoothly performed, and there was no damage of the fixed image at the time of double-sided fixing, and there was no occurrence of winding around the roller and an offset phenomenon.
[0328]
Further, when a full color image was formed on the OHP film, the full color image was excellent in translucency, and a clear full color image could be projected onto the screen. The evaluation results are shown in Table 15.
[0329]
Comparative Example 44
Comparative cyan toner No. 1 of Comparative Example 1 A two-component developer having a comparative magenta toner No. 1 of Comparative Example 22; 1 and a comparative yellow toner No. 1 of Comparative Example 33. Using a two-component developer having 1 in the same manner as in Example 13, a full color mode image output test was performed. The evaluation results are shown in Table 15.
[0330]
Comparative Example 45
Comparative cyan toner no. A two-component developer having a comparative magenta toner no. 2 and a comparative yellow toner No. 1 of Comparative Example 34. Using a two-component developer having 2 in the same manner as in Example 13, a full color mode image output test was performed. The evaluation results are shown in Table 15.
[0331]
Comparative Example 46
Comparative cyan toner no. A two-component developer having a comparative magenta toner no. No. 3 and a comparative yellow toner no. Using a two-component developer having 3 in the same manner as in Example 13, a full color mode image output test was conducted. The evaluation results are shown in Table 15.
[0332]
Comparative Example 47
Comparative cyan toner no. A two-component developer having a comparative magenta toner no. 4 and a comparative yellow toner No. 1 of Comparative Example 36. Using a two-component developer having 4 in the same manner as in Example 13, a full color mode image output test was performed. The evaluation results are shown in Table 15.
[0333]
Comparative Example 48
Comparative cyan toner no. No. 7, two-component developer, Comparative Magenta Toner No. 5 and a comparative yellow toner no. Using the two-component developer having No. 5, a full color mode image output test was conducted in the same manner as in Example 13. The evaluation results are shown in Table 15.
[0334]
Comparative Example 49
Comparative cyan toner No. No. 8 two-component developer, Comparative Magenta Toner No. No. 6 and a comparative yellow toner no. Using the two-component developer having No. 6, a full color mode image output test was conducted in the same manner as in Example 13. The evaluation results are shown in Table 15.
[0335]
[Table 15]

[0336]
【The invention's effect】
The color toner of the present invention is comprehensively excellent in terms of fixability, offset resistance, color mixing, highlight portion reproducibility, and durability of a large number of sheets, and is used for forming a fixed image on both sides of a transfer material. Each process can be performed smoothly. Further, in the color toner and the image forming method of the present invention, the fixed image absorbs and / or adsorbs the silicone oil applied to the fixing roller at the time of fixing, thereby eliminating oil unevenness on the surface of the fixed image, and the other surface of the transfer material ( The problem that the silicone oil adhering to one surface (front surface) of the transfer material when the color toner image is transferred to the back surface can contaminate the surface of the transfer drum can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is a laser beam copying machine for full-color image formation (also as a printer) having black toner in addition to three colors of cyan toner, magenta toner and yellow toner equipped with a fixing device suitable for the present invention. It is a longitudinal cross-sectional view which shows the structure of use possible.
FIG. 2 is a schematic diagram illustrating a configuration of a fixing device.
FIG. 3 is a diagram showing an X-ray diffraction pattern of α-type alumina.
FIG. 4 is a diagram showing an X-ray diffraction pattern of γ-type alumina.
[Explanation of symbols]
10a Fixing roller
10b Pressure roller
62 Rubber-like member
63 Fluororesin
C1 cleaning blade

Claims (56)

(I) a color toner having at least a binder resin and a colorant, and (ii) an external additive,
(A) The color toner has a weight average particle diameter of 5 to 8 μm, a number average particle diameter of 4.5 to 7.5 μm, and 5 to 40% by number of particles having a particle diameter of 4 μm or less in the number distribution of the color toner. In the volume distribution of the color toner, particles having a particle size of 10.08 μm or more are 7 vol% or less
(B) inorganic powder which is strontium titanate powder and hydrophobic alumina fine powder are externally added to the color toner particles as external additives,
The inorganic powder has a length average particle size of 0.2 to 2 μm,
The hydrophobic alumina fine powder has a length average particle size of 0.005 to 0.1 μm,
(C) The binder resin is a polyester resin that is crosslinked with a crosslinking agent;
(D) The color toner particles have a chloroform insoluble content of 0 to 20 mg / 1 g.
(E) The color toner has a storage elastic modulus (G ′ ₁₃₀ ) at a temperature of 130 ° C. of 2 × 10 ³ to 2 × 10 ⁴ [dyn / cm ² ], and a storage elastic modulus (G ′ ₁₇₀ ) at a temperature of 170 ° C. color toner but to a 5 × ¹⁰ 3 ~5 × ^{10 4} [dyn / cm _^2], the value of _{G '170 /} G' ₁₃₀ is characterized in that it is a 0.25 to 10.   The color toner according to claim 1, wherein the color toner particles have a chloroform insoluble content of 0 to 15 mg / 1 g.   The color toner according to claim 1 or 2, wherein the inorganic powder is externally added in an amount of 0.01 to 2 parts by weight per 100 parts by weight of the color toner particles.   The color toner according to claim 1 or 2, wherein the inorganic powder is externally added in an amount of 0.05 to 1 part by weight per 100 parts by weight of the color toner particles.   The color toner according to claim 1, wherein the hydrophobic alumina fine powder is externally added in an amount of 0.5 to 5 parts by weight per 100 parts by weight of the color toner particles.   The color toner according to any one of claims 1 to 4, wherein the hydrophobic alumina fine powder is externally added in an amount of 0.6 to 3 parts by weight per 100 parts by weight of the color toner particles. The color toner according to any one of claims 1 to 6, wherein the hydrophobic alumina fine powder has a BET specific surface area of 130 m ² / g or more. The color toner according to claim 1, wherein the hydrophobic alumina fine powder has a BET specific surface area of 150 to 400 m ² / g.   The color toner according to any one of claims 1 to 8, wherein the hydrophobic alumina fine powder has a degree of hydrophobicity of 30 to 90%.   The color toner according to any one of claims 1 to 8, wherein the hydrophobic alumina fine powder has a degree of hydrophobicity of 40 to 80%.   The color toner according to any one of claims 1 to 10, wherein the hydrophobic alumina fine powder is surface-treated with an alkylalkoxysilane.   The color toner according to claim 1, wherein the hydrophobic alumina fine powder has a γ-type crystal structure.   The color toner according to claim 1, wherein the hydrophobic alumina fine powder has an amorphous structure. The color toner according to claim 1, wherein the value of G ′ ₁₇₀ / G ′ ₁₃₀ is 0.5 to 10. The color toner according to claim 1, wherein the value of G ′ ₁₇₀ / G ′ ₁₃₀ is 1 to 10. The color toner usually has an image density (D _0.5 ) after fixing once when the unfixed color toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ² . The color toner according to claim 1, which has a coloring power of 2 or more. The color toner usually has an image density (D _0.5 ) after fixing once of 1, when the unfixed color toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ² . The color toner according to claim 1, which has a coloring power of 3 or more. The color toner usually has an image density (D _0.5 ) after fixing once of 1, when the unfixed color toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ² . The color toner according to claim 16, which has a coloring power of 2 to 1.8. The color toner usually has an image density (D _0.5 ) after fixing once of 1.3 when the unfixed toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ^2. The color toner according to claim 17, which has a coloring power of 1 to 1.7. The crosslinked polyester resin is a crosslinked polyester resin produced by polycondensation of a monomer having at least a divalent alcohol component, a divalent acid component, and a trivalent or higher carboxylic acid component. The color toner according to any one of 1 to 19 . The crosslinked polyester resin has a glass transition temperature of 50 to 80 ° C., a number average molecular weight (Mn) of 1000 to 9000, an Mw / Mn of 5.0 or less, and a molecular weight of the main peak in the molecular weight distribution of GPC ( The color toner according to claim 20 , wherein Mp) is from 5000 to 12000. The color toner according to claim 20 or 21 , wherein the crosslinked polyester resin has a chloroform insoluble content of 0 to 1 wt% (resin basis). The color toner according to claim 20 or 21 , wherein the crosslinked polyester resin has a chloroform-insoluble content of 0 to 0.9% by weight. The color toner according to claim 20 or 21 , wherein the cross-linked polyester resin has a chloroform insoluble content of 0 to 0.5 wt%. Color toner, any of the color toners of claims 1 to 24 which is a cyan toner. Color toner, any of the color toners of claims 1 to 24 magenta toner. Color toner, any of the color toners of claims 1 to 24 which is yellow toner. (1) The electrostatic image carrier is charged, the charged electrostatic image carrier is exposed to form an electrostatic image on the electrostatic image carrier, and the electrostatic image is developed with a developer having color toner. A color toner image is formed on the electrostatic image carrier, the color toner image on the electrostatic image carrier is transferred to one surface of the transfer material, and the transferred color toner image is transferred to the transfer material by heating and pressing means. To form a color image on one side of the transfer material by heat and pressure fixing to one side of
(2) After the transfer, the color toner remaining on the electrostatic image carrier is cleaned by a cleaning means, the cleaned electrostatic image carrier is charged, and the charged electrostatic image carrier is exposed to electrostatic image. Is formed on the electrostatic image carrier, and the electrostatic image is developed with a developer having color toner to form a color toner image on the electrostatic image carrier, and the color toner image on the electrostatic image carrier is The color toner image is transferred to the other surface of the transfer material having a fixed image of the color toner image on the surface, and the transferred color toner image is heated and pressure-fixed to the other surface of the transfer material by the heat and pressure fixing means. An image forming method for forming a fixed image of a color toner image on both sides,
Color toner used to form color images on both sides of the transfer material
(I) color toner particles containing at least a binder resin and a colorant, and (ii) an external additive,
(A) The color toner has a weight average particle diameter of 5 to 8 μm, a number average particle diameter of 4.5 to 7.5 μm, and 5 to 40% by number of particles having a particle diameter of 4 μm or less in the number distribution of the color toner. In the volume distribution of the color toner, particles having a particle size of 10.08 μm or more are 7 vol% or less
(B) inorganic powder which is strontium titanate powder and hydrophobic alumina fine powder are externally added to the color toner particles as external additives,
The inorganic powder has a length average particle size of 0.2 to 2 μm,
The hydrophobic alumina fine powder has a length average particle size of 0.005 to 0.1 μm,
(C) The binder resin is a polyester resin that is crosslinked with a crosslinking agent;
(D) The color toner particles have a chloroform insoluble content of 0 to 20 mg / 1 g.
(E) The color toner has a storage elastic modulus (G ′ ₁₃₀ ) at a temperature of 130 ° C. of 2 × 10 ³ to 2 × 10 ⁴ [dyn / cm ² ], and a storage elastic modulus (G ′ ₁₇₀ ) at a temperature of 170 ° C. Is 5 × 10 ^{3 to} 5 × 10 ⁴ [dyn / cm ² ], and the value of G ′ ₁₇₀ / G ′ ₁₃₀ is 0.25 to 10. The image forming method according to claim 28 , wherein the color toner is a cyan toner. The image forming method according to claim 28 , wherein the color toner is a magenta toner. The image forming method according to claim 28 , wherein the color toner is a yellow toner. (1-1) The electrostatic image carrier is charged, the charged electrostatic image carrier is exposed to form an electrostatic image on the electrostatic image carrier, and the electrostatic image is converted into cyan toner, magenta toner, Development is performed with a first color toner selected from the group consisting of yellow toners, and the first color toner image on the electrostatic charge image carrier is transferred to one surface of the transfer material carried on the transfer drum for transfer. Cleaning the first color toner remaining on the electrostatic image bearing member later by a cleaning means;
(1-2) The cleaned electrostatic charge image carrier is charged, the charged electrostatic image carrier is exposed to form an electrostatic charge image on the electrostatic image carrier, and the electrostatic charge image is transferred to cyan toner, Development is performed with a second color toner selected from the group consisting of magenta toner and yellow toner, and the second color toner image on the electrostatic charge image carrier is transferred to one surface of the transfer material carried on the transfer drum. And cleaning the second color toner remaining on the electrostatic image carrier after the transfer by a cleaning means,
(1-3) The electrostatic image bearing member after cleaning is charged, and the charged electrostatic image bearing member is exposed to form an electrostatic charge image on the electrostatic image bearing member. Development is performed with a third color toner selected from the group consisting of magenta toner and yellow toner, and the third color toner image on the electrostatic charge image carrier is transferred to one surface of the transfer material carried on the transfer drum. And cleaning the third color toner remaining on the electrostatic image bearing member after the transfer by a cleaning means,
(1-4) Cyan toner, magenta toner, and yellow toner satisfy the above conditions (a), (b), (c), (d), and (e) of the color toner,
(1-5) The first, second, and third color toner images transferred to the transfer material are heated and pressure-fixed on one surface of the transfer material by a heating and pressing unit to form a full-color image,
(2-1) The cleaned electrostatic charge image bearing member is charged, and the charged electrostatic charge image bearing member is exposed to form an electrostatic charge image on the electrostatic charge image bearing member. Development is performed with a first color toner selected from the group consisting of magenta toner and yellow toner, and the first color toner image on the electrostatic charge image carrier has a full color image on one surface carried by the transfer drum. The first color toner remaining on the electrostatic charge image carrier after the transfer is transferred to various surfaces of the transfer material, and cleaned by a cleaning means.
(2-2) The cleaned electrostatic image carrier is charged, and the charged electrostatic image carrier is exposed to form an electrostatic image on the electrostatic image carrier, and the electrostatic image is converted to cyan toner, Development is performed with a second color toner selected from the group consisting of magenta toner and yellow toner, and the second color toner image on the electrostatic charge image carrier is transferred to the other surface of the transfer material carried on the transfer drum. And cleaning the second color toner remaining on the electrostatic image carrier after the transfer by a cleaning means,
(2-3) The electrostatic image bearing member after cleaning is charged, and the charged electrostatic image bearing member is exposed to form an electrostatic image on the electrostatic image bearing member. Development is performed with a third color toner selected from the group consisting of magenta toner and yellow toner, and the third color toner image on the electrostatic charge image carrier is transferred to the other surface of the transfer material carried on the transfer drum. And cleaning the third color toner remaining on the electrostatic image bearing member after the transfer by a cleaning means,
(2-4) The cyan toner, magenta toner, and yellow toner satisfy the above conditions (a), (b), (c), (d), and (e) of the color toner,
(2-5) The first, second, and third color toner images transferred to the other surface of the transfer material are heated and pressure-fixed on the other surface of the transfer material by heating and pressing means, and the full color image is transferred to the other surface. The image forming method according to claim 28, wherein the image forming method is also formed. The image forming method according to any one of claims 28 to 32 , wherein the heating and pressing means includes means for applying silicone oil. 34. The image forming method according to claim 28 , wherein the heating and pressing unit includes a fixing roller and a pressing roller including the heating unit, and silicone oil is applied to the fixing roller. 35. The image forming method according to claim 28 , wherein the inorganic powder is externally added in an amount of 0.01 to 2 parts by weight per 100 parts by weight of the color toner particles. 35. The image forming method according to claim 28 , wherein the inorganic powder is externally added in an amount of 0.05 to 1 part by weight per 100 parts by weight of the color toner particles. 37. The image forming method according to claim 28 , wherein the hydrophobic alumina fine powder is externally added in an amount of 0.5 to 5 parts by weight per 100 parts by weight of the color toner particles. 37. The image forming method according to claim 28 , wherein the hydrophobic alumina fine powder is externally added in an amount of 0.6 to 3 parts by weight per 100 parts by weight of the color toner particles. The image forming method according to any one of claims 28 to 38 , wherein the hydrophobic alumina fine powder has a BET specific surface area of 130 m ² / g or more. The image forming method according to any one of claims 28 to 38 , wherein the hydrophobic alumina fine powder has a BET specific surface area of 150 to 400 m ² / g. 41. The image forming method according to claim 28 , wherein the hydrophobic alumina fine powder has a degree of hydrophobicity of 30 to 90%. 41. The image forming method according to claim 28 , wherein the hydrophobic alumina fine powder has a degree of hydrophobicity of 40 to 80%. 43. The image forming method according to claim 28, wherein the hydrophobic alumina fine powder is surface-treated with alkylalkoxysilane. 44. The image forming method according to claim 28 , wherein the hydrophobic alumina fine powder has a γ-type crystal structure. 44. The image forming method according to claim 28 , wherein the hydrophobic alumina fine powder has an amorphous structure. Color toner The image forming method according to claim 28 or 45 values of _{G '170 / G' 130} is from 0.5 to 10. Color _toner, any of the image forming method according to claim 28 or 45 values of _{G '170 /} G' ₁₃₀ is from 1 to 10. The color toner usually has an image density (D _0.5 ) after fixing once of 1, when the unfixed color toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ² . 48. The image forming method according to claim 28 , wherein the image forming method has a coloring power of 2 or more. The color toner usually has an image density (D _0.5 ) after fixing once of 1, when the unfixed color toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ² . 48. The image forming method according to claim 28 , wherein the image forming method has a coloring power of 3 or more. The color toner usually has an image density (D _0.5 ) after fixing once when the unfixed color toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ² . 49. The image forming method according to claim 48 , having a coloring power of 2 to 1.8. The color toner usually has an image density (D _0.5 ) after fixing once of 1.3 when the unfixed toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ^2. The image forming method according to claim 49 , having a coloring power of 1 to 1.7. The crosslinked polyester resin is a crosslinked polyester resin produced by condensation polymerization of a monomer having at least a divalent alcohol component, a divalent acid component, and a trivalent or higher carboxylic acid component. The image forming method according to any one of 28 to 51 . The crosslinked polyester resin has a glass transition temperature of 50 to 80 ° C., a number average molecular weight (Mn) of 1000 to 9000, an Mw / Mn of 5.0 or less, and a molecular weight of the main peak in the molecular weight distribution of GPC ( 53. The image forming method according to claim 52 , wherein Mp) is 5000 to 12000. 54. The image forming method according to claim 52 , wherein the crosslinked polyester resin has a chloroform insoluble content of 0 to 1% by weight (resin basis). 54. The image forming method according to claim 52 or 53 , wherein the crosslinked polyester resin has a chloroform-insoluble content of 0 to 0.9% by weight. 54. The image forming method according to claim 52 , wherein the crosslinked polyester resin has a chloroform insoluble content of 0 to 0.5% by weight.

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