JP3864022B2 - Color toner for electrophotography and method for producing the toner - Google Patents

Description

（前式中、Ｒ^１およびＲ^２は同一、または相異なっていても良く、炭素数２〜４のアルキレン基であり、ｘ、ｙは正の整数であり、その和の平均値は２〜
１６である。）
で示されるジオール成分と、（ロ）２価以上の多価カルボン酸、その無水物及びその低級アルキルエステルからなる群から選ばれる成分を縮合重合して得られるポリエステル樹脂である。
【００１５】
前記一般式（Ｉ）で示されるジオールの例としては、ポリオキシプロピレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシエステル（２）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシプロピレン（６）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシプロピレン（１６）−２，２−ビス（４−ヒドロキシフェニル）プロパン等が挙げられる。なお、ジオール成分に下記のような２官能以上のポリヒドロキシ化合物を、約５モル％以下使用することもできる。エチレングリコール、プロピレングリコール、グリセリン、ペンタエリスリトール、トリメチロールプロパン、水素添加ビスフェノールＡ、ソルビトール、又はそれらのエーテル化ポリヒドロキシル化合物等。
【００１６】
前記、（ロ）の具体的な例としては、フタル酸、イソフタル酸、テレフタル酸、マレイン酸、フマル酸及びそれらの無水物、及びそれらの低級アルキルエステル、トリメリット酸若しくはその無水物を含有する酸、ｎ−ドデセニルコハク酸、ｎ−ドデシルコハク酸、ｎ−ブチルコハク酸、イソ−ドデセニルコハク酸、イソ−オクチルコハク酸等のコハク酸誘導体が挙げられる。特に、これらのコハク酸誘導体を導入することによりトナーとしての低温時の定着性が十分となり、更に光沢性も向上する。
上記ポリエステル樹脂は、通常上記ポリオール成分と多価カルボン酸成分とを不活性ガス雰囲気中で１８０〜２５０℃の温度で縮重合することによって製造することができる。
【００１７】
ポリオール樹脂としては、各種のタイプのものが使用できるが、本発明においては、特にポリオール樹脂として、（ａ）エポキシ樹脂と、（ｂ）２価フェノールのアルキレンオキサイド付加物若しくはそのグリシジエーテルと、（ｃ）エポキシ基と反応する活性水素を分子中に１個有する化合物と、（ｄ）エポキシ基と反応する活性水素を分子中に２個以上有する化合物を反応してなるポリオールを用いることが好ましい。
さらに、前記（ａ）のエポキシ樹脂は、数平均分子量の相異する少なくとも２種以上のビスフェノールＡ型エポキシ樹脂であることが特に好ましい。この場合のポリオール樹脂は、良好な光沢、透明性を付与し、耐オフセット性に効果がある。本発明に用いられるエポキシ樹脂は、好ましくはビスフェノールＡやビスフェノールＦ等のビスフェノールとエピクロロヒドリンと結合して得られたものである。
エポキシ樹脂は、安定した定着特性や光沢を得るために数平均分子量の相違する少なくとも２種以上のビスフェノールＡ型エポキシ樹脂で、低分子量成分の数平均分子量が３６０〜２０００であり、高分子量成分の数平均分子量が３０００〜１００００であることが好ましい。さらに低分子量成分が２０〜５０重量％、高分子量成分が５〜４０重量％であることが好ましい。低分子量成分が多すぎたり、分子量が３６０よりさらに低分子の場合は、光沢が出すぎたり、さらには保存性の悪化の可能性がある。また、高分子量成分が多すぎたり、分子量１００００よりさらに高分子の場合は、光沢が不足したり、さらには定着性の悪化の可能性がある。
【００１８】
前記（ｂ）の２価フェノールのアルキレンオキサイド付加物としては、以下のものが例示される。即ち、エチレンオキサイド、プロピレンオキサイド、ブチレンオキサイド及びこれらの混合物とビスフェノールＡやビスフェノールＦ等のビスフェノールとの反応生成物が挙げられる。得られた付加物をエピクロロヒドリンやβ−メチルエピクロロヒドリンでグリシジル化して用いてもよい。特に下記一般式（II）で表わされるビスフェノールＡのアルキルオキサイド付加物のジグリシジルエーテルが好ましい。
【化２】

（式中、Ｒは−ＣＨ_２−ＣＨ_２−、−ＣＨ_２−ＣＨ（ＣＨ_３）−又は−ＣＨ_２−ＣＨ_２−ＣＨ_２−基であり、またｎ、ｍは繰り返し単位の数であり、各々１以上であって、ｎ＋ｍ＝２〜６である。）
前記２価フェノールのアルキレンオキサイド付加物若しくはグリシジエーテルは、ポリオール樹脂に対して１０〜４０重量％含まれていることが好ましい。ここで、量が少ないと、カールが増すなどの不具合が生じ、またｎ＋ｍが７以上であったり、量が多すぎると、光沢が出すぎたり、更には保存性の悪化の可能性がある。
【００１９】
前記（ｃ）のエポキシ基と反応する活性水素を分子中に１個有する化合物としては、１価フェノール類、２級アミン類、カルボン酸類がある。１価フェノール類としては、以下のものが例示される。即ち、フェノール、クレゾール、イソプロピルフェノール、アミノフェノール、ノニルフェノール、ドデシルフェノール、キシレノール、ｐ−クミルフェノール等が挙げられる。２級アミン類としては、ジエチルアミン、ジプロピルアミン、ジブチルアミン、Ｎ−メチル（エチル）ピペラジン、ピペリジンなどが挙げられる。また、カルボン酸類としては、プロピオン酸、カプロン酸などが挙げられる。
【００２０】
前記（ｄ）のエポキシ基と反応する活性水素を分子中に２個以上有する化合物としては、２価フェノール類、多価フェノール類、多価カルボン酸類が挙げられる。２価フェノールとしては、ビスフェノールＡやビスフェノールＦ等のビスフェノール類が挙げられる。また、多価フェノール類としては、オルソクレゾールノボラック類、フェノールノボラック類、トリス（４−ヒドロキシフェニル）メタン、１−〔α−メチル−α−（４−ヒドロキシフェニル）エチル〕ベンゼンが例示される。多価カルボン酸類としては、マロン酸、コハク酸、グルタル酸、アジピン酸、マレイン酸、フマル酸、フタル酸、テレフタル酸、トリメット酸、無水トリメリット酸が例示される。
【００２１】
本発明の主鎖にエポキシ樹脂部とアルキレンオキサイド部を有するポリオール樹脂を得るためには、種々の原材料の組み合わせが可能である。例えば両末端グリシジル基のエポキシ樹脂と両末端グリシジル基の２価フェノールのアルキレンオキサイド付加物を、ジハライドやジイソシアネート、ジアミン、ジオチール、多価フェノール、ジカルボン酸と反応させることにより得ることができる。このうち、２価のフェノールを反応させるのが反応安定性の点で最も好ましい。また、ゲル化しない範囲で多価フェノール類や多価カルボン酸類を、２価フェノールと併用するのも好ましい。ここで多価フェノール類、多価カルボン酸類の量は、全量に対し１５％以下、好ましくは１０％以下である。
前記のポリエステル樹脂やポリオール樹脂は、高い架橋密度を持たせると、透明性や光沢度が得られにくくなり、好ましくは非架橋若しくは弱い架橋（ＴＨＦ不溶分５％以下）とすることが好ましい。
【００２２】
結着樹脂として、前記のポリエステル樹脂やポリオール樹脂に加えて、必要に応じて以下の樹脂を使用することもできる。ポリスチレン、ポリｐ−クロロスチレン、ポリビニルトルエン等のスチレン及びその置換体の単重合体；スチレン−ｐ−クロロスチレン共重合体、スチレンープロピレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−ビニルナフタリン共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸エチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−アクリル酸オクチル共重合体、スチレン−メタクリル酸メチル共重合体、スチレン−メタクリル酸エチル共重合体、スチレン−メタクリル酸ブチル共重合体、スチレン−α−クロルメタクリル酸メチル共重合体、スチレン−アクリロニトリル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルエチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソプレン共重合体、スチレン−アクリロニトリル−インデン共重合体、スチレン−マレイン酸共重合体、スチレン−マレイン酸エステル共重合体などのスチレン系共重合体；ポリメチルメタクリレート、ポリブチルメタクリレート、ポリ塩化ビニル、ポリ酢酸ビニル、ポリエチレン、ポリプロピレン、ポリウレタン、ポリアミド、エポキシ樹脂、ポリビニルブチルブチラール、ポリアクリル酸樹脂、ロジン、変性ロジン、テルペン樹脂、フェノール樹脂等。
【００２３】
着色剤としては、イエロー、マゼンタ、シアン、ブラック色のトナーを得ることが可能な染顔料が使用できる。例えば、カーボーンブラック、ランプブラック、アニリンブラック、群青、アニリンブルー、フタロシアニンブルー、フタロシアニングリーン、ハンザイエローＧ、ローダミン６Ｇ、レーキ、カルコオイルブルー、クロムイエロー、キナクリドン、ベンジジンイエロー、ローズベンガル、トリアリルメタン系染料等の染顔料など、従来公知のいかなる染顔料をも単独或いは混合して使用し得るが、特にイエロートナーに用いられる着色剤には、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １８０を用いることが好ましい。この着色剤は、特に凝集性が強く、通常のトナー製造方法、即ち、結着樹脂と着色剤及び帯電制御剤を溶融混練する等の方法では、この着色剤の強い凝集状態を解くことができない。このため、得られたトナー粒子中の着色剤粒子の分散径は大きく、従ってトナーの透明性も悪くなり、カラートナーの重要品質である色再現性に劣るものしか得られない。ところが、本発明の製造方法によると、凝集した着色剤粒子を十分に解きほぐすことができ、透明性に優れたトナーを得ることができる。本発明の着色剤を用いることで、長期使用によってもトナー表面からの着色剤の剥離がなく、二成分現像剤におけるキャリア表面の汚染や、一成分現像における現像ローラーへのフィルミング等が防止され、更にまた定着部材へのフィルミングが防止されることが明らかとなった。
【００２４】
また、マゼンタトナーに用いられる着色剤には、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２を用いることが、他のマゼンタ着色剤と比べて色再現範囲が広いため好ましい。しかし、この着色剤も、イエロー着色剤のＣ．Ｉ．ＰｉｇｍｅｎｔＹｅｌｌｏｗ １８０と同様、特に凝集性が強く、通常のトナー製造方法、即ち、結着樹脂と着色剤または必要に応じて帯電制御剤等の他の材料を溶融混練する等の方法では、この着色剤の強い凝集状態を解くことができない。このため、得られたトナー粒子中の着色剤粒子の分散径は大きく、従ってトナーの透明性も悪くなり、カラートナーの重要品質である色再現性に劣るものしか得られない。ところが、本発明の製造方法により、凝集した着色剤粒子を十分に解きほぐすことができ、透明性に優れたトナーを得ることができる。この着色剤を用いることで、長期使用によってもトナー表面からの着色剤の剥離がなく、二成分現像剤におけるキャリア表面の汚染や、一成分現像における現像ローラへのフィルミング等が防止され、更にまた定着部材へのフィルミングが防止されることが明らかとなった。
これらの着色剤の含有量は結着樹脂１００重量部に対して、通常１〜３０重量部、好ましくは３〜２０重量部である。
【００２５】
本発明のトナーに用いられる離型剤は、トナー中での平均分散粒径が０．１〜３μｍのものを使用することで、定着時に離型剤がトナー表面にしみ出して定着部材にオイルを塗布しない状態においても十分な耐オフセット性を有する。また、離型剤のトナー中での平均分散粒径が０．１μｍよりも小さい場合には、定着時に十分な離型剤のしみ出し効果が弱く、十分な耐オフセット性が得られない場合があり、逆に３μｍよりも大きい場合には、トナーの流動性の低下や、トナー表面からの脱離によるキャリア表面への汚染によって帯電特性を悪化させる場合がある。離型剤のトナー中での平均分散粒径は、透過型電子顕微鏡により確認することができ、本発明におけるこの定義は、倍率１０万倍での拡大写真によりランダムに選択した離型剤部分１００点を平均したものである。
【００２６】
本発明のトナーに用いられる離型剤の融点は、特に７５〜１００℃であることが好ましい。この範囲よりも低い場合は、オフセットが発生しやすくなり、さらにトナーの保存時にブロッキングが発生しやすくなり、逆に高い場合は、十分な定着性が得られない場合がある。
ここで、離型剤の融点は以下のように測定した。理学電機製の融点測定器（Ｒｉｇａｋｕ ＴＨＥＲＭＯＦＬＥＸ ＴＧ８１１０型）により昇温速度１０℃／ｍｉｎの条件にて測定し、吸熱曲線の主体極大ピークを融点とした。
【００２７】
前記離型剤は、重量平均分子量Ｍｗと数平均分子量Ｍｎの比であるＭｗ／Ｍｎが１．０〜１．２であることが好ましい。その理由は十分に明らかではないが、Ｍｗ／Ｍｎを１．０〜１．２とすることで、定着時の離型剤のしみ出しが効率的に行われるため、十分な耐オフセット性が得られるものと考えられる。
なお、離型剤の分子量測定は以下の通りに行なった。
ＧＰＣによる分子量測定
４０℃の恒温槽中でカラムを安定させ、溶離液としてＴＨＦを１ｍｌ／ｍｉｎの流速で流し、試料温度０．０５〜０．５重量部に調整した試料のＴＨＦ溶液を２００μｌ注入して測定を行なう。試料の分子量はあらかじめ作成した検量線に基づき、リテンションタイムから決定した分子量分布より算出した。このときの検量線は数種類の単分散ポリスチレンを標準試料として作成したものである。分析カラム：Ｅｘｃｅｌ ｐａｋ ＳＥＣ−Ｇ１４／Ｇ１６／Ｇ１８〔横河アナリティカルシステムズ（株）製〕。
【００２８】
また、本発明のトナーに用いられて離型剤は、結着樹脂に対して非相溶であれば、いかなる材料も使用可能であるが、特にエステル系又はオレフィン系のワックスが離型剤として好ましい。これらの離型剤は、結着樹脂中により均一に分散されることから、優れた耐オフセット性を示し、特にポリエステル樹脂やポリオール樹脂を結着樹脂に用いた場合にその効果が高い。
なお、ここでエステル系のワックスとしては、エステル結合を有するワックスを意味し、キャンデリラワックス、カルナウバワックス、ライスワックス等の天然ワックス等が挙げられ、オレフィン系のワックスとしては、ポリエチレンワックス、ポリプロピレンワックス、フィッシャー−トロプシュワックス等が挙げられる。これらの離型剤の含有量は結着樹脂１００重量部に対して、通常１〜２０重量部、好ましくは２〜１０重量部である。
【００２９】
本発明のトナーには、トナーに適切な帯電を付与するために帯電制御剤を含有させることが好ましい。この場合の帯電制御剤としては、カラートナーの色調を損なうことのない透明色から白色系の物質を添加し、負極性若しくは正極性にトナー帯電性を安定化付与することができるものが好ましい。その中でも特にサリチル酸誘導体の金属塩を添加することが、負極性にトナー帯電性を安定化付与する点で効果的である。
ここで使用されるサリチル酸誘導体の金属塩としては、下記一般式（III）で示される化合物が挙げられる。
【化３】

（式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は水素原子又は炭素数１〜１０アルキル基あるいはアリル基を示し、特に水素原子又は炭素数１〜６のアルキル基あるいはアリル基が望ましい。ここでＲ^１、Ｒ^２、Ｒ^３及びＲ^４は同時に同じであっても異なっていてもよい。また、Ｍｅは亜鉛、ニッケル、コバルト、銅、クロムから選ばれるいずれかの金属を示す。）
【００３０】
上記サリチル酸誘導体の金属塩は、ＣＬＡＲＫ，Ｊ．Ｌ Ｋａｏ，Ｈ（１９４８）Ｊ．Ａｍｅｒ．Ｃｈｅｍ．Ｓｏｃ．７０，２１５１に記載された方法によって容易に含成することができる。例えば、溶媒中に２モルのサリチル酸ナトリウム塩（サリチル酸誘導体のナトリウム塩を含む）と、１モルの塩化亜鉛とを添加し、混合し、加温して攪拌することにより亜鉛塩として得ることができる。この金属塩は白色を呈する結晶であり、トナー中に分散させた場合にも着色を示さないものである。金属塩が亜鉛塩以外のものについても、上記の方法に準じて製造することができる。上記サリチル酸誘導体の金属塩中、特に好ましい化合物の具体例を下式（１）〜（８）に示す。
【化４】

上記サリチル酸誘導体の金属塩は、結着樹脂に対する分散性が良好であり、現象ローラ等にフィルミングしにくい。特にサリチル酸誘導体の金属塩の含有量は結着樹脂１００重量部に対し０．５〜８重量部が好ましい。
【００３１】
本発明の電子写真用カラートナーは、下記のような新規な方法により製造される。即ち、結着樹脂と着色剤の混合物を、予め有機溶剤と共に結着樹脂の溶融温度よりも低い温度で１段目の混練を行い、更に結着樹脂及び該結着樹脂と非相溶の離型剤又は必要に応じて帯電制御剤等の他の材料を加えて２段目の加熱溶融混練した後、粉砕して本発明の電子写真用カラートナーを製造する。このとき、１段目の混練物に加える有機溶剤が、（結着樹脂＋着色剤）１００重量部に対して、５〜１５重量部含有させた状態で１段目の混練を行うことが、トナーの透明性を高めるために効果的である。
また、１段目と２段目で加える結着樹脂と着色剤は、好ましくは重量比で８０：２０〜２０：８０、さらに好ましくは７０：３０〜４０：６０である。
これは、有機溶剤を用いることにより、初期的に結着樹脂と着色剤が十分に付着した状態となって、分散が効果的に行なわれる条件になると共に、結着樹脂の溶融温度よりも低い温度で混練を行なうため、混練物の粘度が非常に高く、せん断力が強く働く状態となり、結着樹脂中での着色剤の分散が良好になり、これにより着色剤の分散径が小さくなり、透明性や色再現性に優れ、さらに、高い着色度が得られるものと考えられる。
具体的な方法としては、例えば、結着樹脂、着色剤及び有機溶剤を、スーパーミキサー等のブレンダーにて混合した後、得られた混合物を二本ロール、三本ロール等の混練機により、結着樹脂の溶融温度よりも低い温度で混練して、サンプルを得る。また、有機溶剤としては、結着樹脂との溶解性を考慮しながら、一般的なものを使用できるが、特に、アセトン、トルエン、ブタノン等が、着色剤の分散性の面から好ましい。
この新規な製法によると、得られるカラートナーに含有する着色剤粒子の粒径が小さくなるばかりでなく、該粒子の分散状態の均一性が高くなるため、ＯＨＰによる投影像の色の再現性がより一層良くなる要因になっている。
【００３２】
本発明の電子写真用カラートナーの粒径は、体積平均粒径で３〜１０μｍであることが好ましく、これよりも小粒径の場合には現像時に地汚れの原因となったり、流動性を悪化させトナーの補給やクリーニング性を阻害する場合がある。また、これよりも大粒径の場合には、画像中のチリや、解像性の悪化等が問題となる場合がある。
また、外添剤として、トナーの流動性を向上させる目的でシリカや酸化チタン、アルミナ等を添加することが可能である。なお、必要に応じて、脂肪酸金属塩（ステアリン酸亜鉛、ステアリン酸アルミニウム等）や、ポリフッ化ビニリデン等を添加してもよい。
【００３３】
本発明の電子写真用カラートナーは、一成分トナー及び二成分トナーの双方に適用可能である。二成分トナーとして用いる場合にはキャリアと混合して用いられる。本発明に使用し得るキャリアとしては、例えば鉄粉、フェライト粉、ニッケル粉のごとき磁性を有する粉体、ガラスビーズ等、公知のものがすべて使用可能であるが、これらの表面を樹脂などで被覆する事が好ましい。
この場合、使用される樹脂はポリフッ化炭素、ポリ塩化ビニル、ポリ塩化ビニリデン、フェノール樹脂、ポリビニルアセタール、アクリル樹脂、シリコーン樹脂等である。
この樹脂層の形成法としては、従来と同様、キャリアの表面に噴射法、浸漬法等の手段で樹脂を塗布すればよい。
ここで、これらキャリアの平均粒径は通常１０〜１００μｍ、好ましくは３０〜６０μｍである。なお、樹脂の使用量としては、通常キャリア１００重量部に対して１〜１０重量部である。
さらに、トナーとキャリアとの混合割合は、一般にキャリア１００重量部に対しトナー０．５〜７．０重量部程度が適当である。
本発明の電子写真用カラートナーとしては、少なくともイエロー、マゼンタ、シアンの各トナーから構成されたフルカラーが好ましい。
【００３４】
【実施例】
以下に本発明を実施例により具体的に説明する。しかしながら、本発明はこれらに限定されるものではない。なお、実施例中の部は重量部を表す。
【００３５】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００３６】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．１μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００３７】

をブレンダーで充分混合した後、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．７μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００３８】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００３９】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４０】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．６μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４１】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．７μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４２】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．３μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４３】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．４μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４４】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．４μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４５】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４６】

をブレンダーで充分混合した後、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．２μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４７】

をブレンダーで充分混合したのち、１００℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４８】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．８μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００４９】

をブレンダーで充分混合した後、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．４μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００５０】

をブレンダーで充分混合したのち、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．２μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００５１】

をブレンダーで充分混合した後、１４０℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、本発明のトナーを得た。
【００５２】
比較例１結着樹脂および着色剤を予め有機溶剤と共に該結着樹脂の溶融温度よりも低い温度で混練させた組成物を用いない場合の例である。

をブレンダーで充分混合したのち、１００℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、トナーを得た。
【００５３】
比較例２
本比較例は結着樹脂と離型剤が相溶する場合の例である。

をブレンダーで充分混合したのち、１００℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．５μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、トナーを得た。
【００５４】
比較例３
本比較例は結着樹脂と着色剤を該結着樹脂の溶融温度よりも低い温度で混練する際に、有機溶剤を加えない場合の例である。

をブレンダーで充分混合したのち、１００℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．２μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、トナーを得た。
【００５５】
比較例４
結着樹脂および着色剤を予め有機溶剤と共に行う混練操作を該結着樹脂の溶融温度より高い温度で行った場合の例である。

をブレンダーで充分混合したのち、１００℃に加熱した２軸混練機にて溶融混練した。混練物を水冷後、カッターミルで粗粉砕し、ジェット気流を用いた微粉砕機で粉砕後、風力分級装置を用いて、体積平均粒径７．８μｍの母体着色粒子を得た。
更に、母体着色粒子１００部に対して、疎水性シリカ０．７５重量部を加え、ヘンシェルミキサーにて混合を行い、トナーを得た。
【００５６】

を流動床を用いて芯材料に対し、１．２重量部コーティングし、更に、２１０℃で２時間焼性を行い、上記樹脂で被覆されたキャリアを得た。
現像剤の作成
実施例１〜１７及び比較例１〜４で得られたトナー各５部と、上記キャリア９５部をターブラーミキサーで混合し、現像剤を得た。
得られた各現像剤を、ヒーターを内蔵した外径６０ｍｍのシリコンローラからなる定着ローラと、外径６０ｍｍのテフロンチューブ被覆シリコンローラからなる加圧ローラで構成される定着装置を有し、該定着装置のオイル塗布機構を除去したフルカラー複写機（ＰＲＥＴＥＲ５５０、リコー社製）（図１）にセットし、以下の各種評価を行った。
【００５７】
評価１：定着温度範囲
上記のフルカラー複写機（ＰＲＥＴＥＲ５５０、リコー社製）を用いて、複写紙（ＴＹＰＥ６０００＜７０Ｗ＞、リコー社製）に、イエロー、マゼンタ、シアンのいずれか単色からなる付着量が１．０±０．１ｍｇ／ｃｍ^２のベタ画像を作成し、以下の定着条件で定着部材の温度が可変となるように調整を行ないオフセットの発生しない温度を測定した。この時の結果を表１に示した。
定着機線速：１８０±２ｍｍ／ｓｅｃ．
定着ニップ幅：１０±１ｍｍ
評価２：光沢度
上記の単色画像サンプルにおいて、定着部材表面温度が１６０℃の時におけるサンプルの光沢度を、日本電色工業株式会社製のグロスメーターにより入射角６０°により計測した、この光沢は、値の高い程光沢感が出る。フルカラーのコピー画像としては適度な光沢が好まれ、１５〜３０％程度が好ましい。この時の結果を表１に示した。
評価３：ヘーズ度
上記単色画像サンプルを転写紙としてＯＨＰシート（ＴＹＰＥ ＰＰＣ−ＤＸ、リコーエレメックス社製）を用い、定着部材表面温度が１６０℃の時におけるサンプルのヘーズ度をスガ試験機株式会社の直読ヘーズコンピュータＨＧＭ−２ＤＰ型により測定した。このヘーズ度は、曇り度とも言われ、トナーの透明性を示す尺度として測定され、値の低いほど透明性が高く、ＯＨＰ紙を用いた場合の発色性が良好なものとなる。また、良好な発色性を示すヘーズ度の値は、２５％以下が好ましい。この時の結果を表１に示した。
また、実施例及び比較例の各トナーについて、以下の評価を行った。
評価４：トナー中の離型剤分散径
トナー中の離型剤の分散径は、種々の方法で測定されるが、ここでは、トナーの超薄切片を作成し、透過型電子顕微鏡（日立社製Ｈ−９０００Ｈ）を用いて、トナーの断面写真（倍率×１００，０００）を撮影することにより行った。本写真から、ランダムの選択した１００点の離型部分の分散径から平均値を求めた。ここで、１粒子の分散径は最長径と最短径の平均とし、また、凝集状態にあるものは凝集体自身を１粒子とした、この時の結果を表１に示した。
【００５８】
【表１】

【００５９】
【発明の効果】
本発明によれば、離型剤を含有するカラートナーにおいても透明性や色再現性に優れ、また、着色度が高く、さらに適度な光沢性と良好な定着性と十分な耐オフセット性を有し、定着部材にオイルを用いない定着装置に適用できる電子写真用カラートナー及びその製造方法が提供される。
【図面の簡単な説明】
【図１】実施例及び比較例において使用されたフルカラー複写機（ＰＲＥＴＥＲ５５０、リコー社製）の断面図
【符号の説明】
１０１ スキャナ
１１２ プリンタ
２０１ 複写機
２０２ 黒現像ユニット
２０３ シアン現像ユニット
２０４ マゼンタ現像ユニット
２０５ イエロー現像ユニット
２０６ 中間転写ベルト
２０７ 帯電装置
２０８ レーザ光学系
２０９ コンタクトガラス
２１０ 露光ランプ（ハロゲンランプ）
２１１ 反射ミラー
２１２ 結像レンズ
２１３ ＣＣＤ イメージセンサ
２１４ クリーニング装置
２１５ 感光体
２１６ 給紙ユニット
２１７ 転写バイアスローラ
２１８ 搬送ベルト
２１９ 定着装置
２２０ 排紙トレイ
２２１ バイアスローラ
２２２ ベルトクリーニング装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner applied to an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like. Specifically, the toner can be applied to a fixing device that does not use oil as a fixing member, and has excellent transparency and color reproducibility. The present invention also relates to an electrophotographic color toner having a high degree of coloring, moderate glossiness, good fixability, and sufficient offset resistance, and a method for producing the same.
[0002]
[Prior art]
As conventional electrophotographic methods, various methods are described in U.S. Pat. No. 2,276,91, Japanese Patent Publication No. 42-23910, Japanese Patent Publication No. 43-24748, and the like. An electric latent image is formed on the photoconductive support by the above means, and then the latent image is developed with toner to obtain a visible image, or, if necessary, a powder image is transferred to paper or the like and then heated and heated. It is fixed by pressurization or solvent vapor to obtain a visible image. Further, as described in U.S. Pat. No. 2,962,374, as a full-color electrophotographic method for obtaining a multicolor image of color, exposure is performed by decomposing at least an image into three color signals of yellow, magenta, and cyan. Then, the above process is repeated at least a plurality of times using process color toners such as yellow, magenta, and cyan, and the toner images are superimposed to obtain a multicolor image of color.
[0003]
In recent years, hard copy technology using an electrophotographic method has been rapidly developed from black and white to full color, and the full color market is particularly expanding. Color image formation by full-color electrophotography generally reproduces all colors using three color toners of three primary colors, yellow, magenta, and cyan, or four colors including black. In the general method, first, an electrostatic latent image is formed on a photoconductive layer by passing light from an original through a color separation light transmission filter having a complementary color and toner color relationship. Subsequently, the toner is held on a support through development and transfer processes. Next, the above-described steps are sequentially performed a plurality of times, and the toner is superimposed on the same support while matching the registration, and a final full-color image is obtained by fixing only once. In full-color electrophotography in which development is performed a plurality of times and several toner images of different colors are required to be superimposed on the same support, the fixing characteristics that the color toner should have are extremely important factors. . In other words, the fixed color toner needs to have moderate glossiness and glossiness while suppressing irregular reflection by toner particles as much as possible. In addition, the toner must be a color toner that has transparency that does not interfere with the toner layer of different color tone below the toner layer and has a wide color reproducibility.
[0004]
In general, a color toner is manufactured by melting and kneading a binder resin and a colorant or other materials such as a charge control agent as required, and further classifying the pulverized product to a predetermined particle size.
In addition, as a colorant for these color toners, an organic pigment-based colorant that is superior to dye-based colorants from the viewpoint of light resistance and safety is generally used.
However, since the organic pigment-based colorant forms an aggregate in which the primary particles of the organic pigment are collected in the drying process at the time of producing the pigment, the binder resin and the colorant, which are the usual color toner production methods, are used. Alternatively, in the method of melt-kneading other materials such as a charge control agent as necessary, the strong aggregation state of the colorant cannot be solved, so that the colorant is not easily dispersed uniformly in the binder resin. Because the primary particles of the pigment are present in the toner in the form of aggregates, the transparency, which is one of the most important characteristics of the full-color toner, is greatly deteriorated, and the color reproducibility and the light transmittance of the OHP film are greatly reduced. In addition, a sufficient degree of coloring cannot be obtained.
Here, toner with a low degree of coloring needs to increase the amount of toner attached at the time of development. In particular, when copying a full-color image, it is necessary to superimpose at least two colors of toner, and the amount of adhesion increases accordingly. Therefore, the transparency further deteriorates and the color reproducibility tends to be inferior.
Furthermore, toner with a low degree of coloration increases the amount of toner consumed particularly in the development of a solid portion. Therefore, it is necessary to replenish the toner in the developing device frequently. It is difficult to uniformly agitate the toner and the carrier, and it becomes easy to generate background stains. Also, when a solid image is output, transfer unevenness called “firefly” and white spots are likely to occur on the image, and a uniform solid image is formed. It is difficult to obtain.
Further, when the toner adhesion amount is increased, toner flickering is likely to occur in the thin line portion called “transfer dust”. Particularly, in the case of copying a thin line in a full-color image, it is necessary to superimpose at least two colors of toner. In particular, this tendency is remarkable because the amount of adhesion increases further.
[0005]
In order to solve this problem, Japanese Patent Laid-Open Nos. 62-30259, 62-280755, 2-66561, 2-293867, 3-107869, and Japanese Patent Laid-Open No. -1087070, JP-A-3-185459, JP-A-3-269542, JP-A-3-269543, and the like improve the dispersion of organic pigments in toner using processed pigments There is a proposed method. In the processed pigments described in these publications, first, a dry organic pigment is heated and melt-kneaded with a binder resin so as to have a higher concentration than a normal pigment concentration used in the toner, and further, a pigment concentration suitable for the toner is used. Thus, it is manufactured by diluting, melting and kneading using a binder resin. However, these organic pigment-based colorants form agglomerated particles in which primary particles of the organic pigment are collected in the drying process at the time of producing the pigment, and these agglomerated particles are formed using the above-described method. However, it cannot be finely dispersed until it does not affect the light transmittance of the toner.
As another method, for example, a method of dissolving a raw material in a solvent and mixing it and then evaporating the solvent to prepare a master batch is described in JP-A-61-156054. However, the colorant is not sufficiently dispersed because sufficient shearing force is not applied.
In JP-A-62-127847, an aqueous dispersion of particulate phthalocyanine pigment obtained by an acid paste method or an acid slurry method is mixed in a binder resin and organic solvent solution without drying as it is. Therefore, phthalocyanine can be uniformly dispersed in the binder resin in the form of fine particles. However, in this method, it is necessary to use a large amount of an organic solvent in order to dissolve the binder resin. And there is a problem that the pigment is easily re-aggregated when the organic solvent is removed.
In JP-A-7-311479, a pigment-dispersed resin obtained by heat-treating a pigment-containing water-containing paste into a pigment-dispersing resin solution is used. By using an incompatible resin with a difference in SP value, it is said to be excellent in transparency, offset resistance, and wrapping resistance. However, a resin that disperses the binder resin and the pigment is used and has a different compatibility. Therefore, the refractive index becomes high and sufficient transparency cannot be obtained.
[0006]
On the other hand, fixing devices used for fixing color toners use a member using a material having excellent surface peelability, but most have a member surface coated with oil. However, the application of a large amount of oil to increase the releasability requires problems such as oil stains on the transfer paper, cost increase, and space for the tank for storing the oil, and the size of the fixing device is increased.
In general, the reason for applying oil for fixing color toner is as follows. That is, in general, color toners need to have higher heat-meltability and lower viscosity during fixing heating than black toner for black and white printing to obtain gloss and transparency. However, since the toner using such a resin tends to decrease the cohesive force between molecules at the time of heat melting, the adhesion of the toner to the heat member increases when passing through the fixing member, and a high temperature offset phenomenon occurs. Therefore, in order to prevent this high temperature offset, it is common to apply oil to the fixing member to reduce the adhesion of toner to the fixing member.
In addition, so-called oil-less toners in which no oil is applied to the fixing member have been tried. Generally, a release agent is dispersed in the toners as described in JP-A-8-220808, JP-A-9-106105, and JP-A-9-106105. No. 9-304964, JP-A-9-304971, JP-A-10-207116, JP-A-10-207126, JP-A-10-254173, JP-A-10-293425, JP-A-11-2917, JP-A-11 No. 24313, Japanese Patent Laid-Open No. 11-249341, and the like.
However, in the case of a color toner in which a release agent is dispersed, sufficient transparency cannot be obtained due to the influence of the release agent present on the toner surface, and the fluidity of the toner itself is greatly deteriorated. Further, in the case of a color toner, it is necessary to sufficiently exude the release agent from the toner whose viscosity has been reduced as described above, and it is difficult to prevent offset. In addition, in the case of a highly viscous toner such as black toner for black and white printing, since the intermolecular cohesive force at the time of thermal melting of the toner is high, offset can be prevented by oozing out a small amount of the release agent. Sufficient toner is not melted, and transparency and glossiness are insufficient.
Further, combinations with the colorants subjected to the pretreatment as described above are also disclosed in JP-A-63-205664, JP-A-3-107869, JP-A-3-107870, JP-A-3-185457, and JP-A-3. -269542, JP-A-3-269543, JP-A-7-219274, JP-A-7-311479, JP-A-11-30876, and the like.
Specifically, in JP-A-63-205664, in the first step, a colorant and a wax and, if necessary, a charge control agent, a kneaded product subjected to strong shearing in the molten state of the wax is prepared. Next, in the second step, the kneaded product obtained in the first step, the resin and, if necessary, other additives are kneaded by applying a shearing force weaker than that in the first step.
However, in this method, since the resin is not added in the kneading in the first step, the kneaded product in the first step is not sufficiently dispersed in the resin in the second step, and sufficient transparency is obtained. I can't get it.
[0007]
In JP-A-3-107869, JP-A-3-107870, JP-A-3-185559, JP-A-3-269542, and JP-A-3-269543, a part of a binder resin and a colorant are previously melt-kneaded. When a processed pigment, usually called a masterbatch, is prepared, and then the remaining binder resin and a release agent are added to the processed pigment to perform further melt-kneading. In this case, the shearing force during kneading is weakened. In particular, in color toners, it is common to use a resin having a low melt viscosity as the binder resin. Since the pigments used are also poorly compatible with the binder resin, sufficient colorant dispersion cannot be obtained inevitably, and transparency is lowered.
In JP-A-7-219274 and JP-A-7-311479, a pigment-dispersed resin obtained by mixing a pigment-containing water-containing paste into a pigment-dispersing resin liquid and then heat-treating is further used. In addition, by using an incompatible resin having a difference in SP value from the binder resin, the surface of the pigment is coated with the incompatible resin with the binder resin, so that the polyolefin wax is not taken into the pigment. It is said that transparency, offset resistance, and wrapping resistance are improved, but because the resin used to disperse the binder resin and the pigment is different in compatibility, this increases the refractive index. High transparency cannot be obtained.
In JP-A-11-30876, a processed pigment is prepared by adding a release agent to a binder resin and a colorant and melt-kneading them, and then adding the remaining binder resin and a charge control agent to the processed pigment. However, if a release agent is added and melt-kneaded at the time of preparation of the processed pigment, the shearing force applied during the kneading is inevitably weakened. Since it is common to use a resin having a low melt viscosity, the shearing force tends to be further reduced, and the dispersion of the colorant tends to be insufficient.
For these reasons, color toners containing release agents are also excellent in transparency and color reproducibility, have a high degree of coloring, and have moderate glossiness, good fixability, and sufficient offset resistance. At present, a color toner that can be applied to a fixing device that has a toner and does not use oil as a fixing member has not been obtained.
[0008]
[Problems to be solved by the invention]
The object of the present invention is to solve the above-mentioned problems in the prior art, and in a color toner containing a release agent, it is excellent in transparency and color reproducibility, has a high degree of coloring, and has an appropriate glossiness and goodness. An object of the present invention is to provide an electrophotographic color toner that can be applied to a fixing device that has a fixing property and sufficient offset resistance and that does not use oil as a fixing member, and a method for manufacturing the same.
[0009]
[Means for Solving the Problems]
According to the present invention, in an electrophotographic color toner comprising at least a binder resin, a release agent incompatible with the binder resin, and a colorant, the mixture of the binder resin and the colorant is previously mixed with an organic solvent. A fixing member for obtaining a color image in an electrophotographic system was used by providing a color toner for electrophotography using a composition kneaded at a temperature lower than the melting temperature of the binder resin. In the fixing method, the color toner containing a release agent is excellent in transparency, has a moderate glossiness, good fixing property and sufficient offset resistance, and uses no fixing member for oil. An electrophotographic color toner applicable to the apparatus can be obtained.
[0010]
The contents of the present invention will be described in detail and specifically below.
In an electrophotographic color toner comprising at least a binder resin, a release agent incompatible with the binder resin, and a colorant, a mixture of the binder resin and the colorant is kneaded with an organic solvent in advance. The binder resin and the colorant are sufficiently adhered to each other, and the dispersion is effectively performed. The kneaded product is kneaded at a temperature lower than the melting temperature of the binder resin, so that the viscosity of the kneaded product is increased. Is very high and the shearing force works strongly, the dispersion of the colorant in the binder resin is good, the dispersion diameter of the colorant is small, and good transparency is obtained.
[0011]
As a specific method for kneading the mixture of the binder resin and the colorant with the organic solvent in advance, for example, the binder resin, the colorant, and the organic solvent are obtained after mixing with a blender such as a super mixer. The obtained mixture is kneaded at a temperature lower than the melting temperature of the binder resin by a kneader such as a two-roll or three-roll to obtain a sample. Moreover, as an organic solvent, a general thing can be used, considering the solubility with a binder resin, However, Acetone, toluene, a butanone, etc. are especially preferable from the surface of the dispersibility of a coloring agent.
According to this manufacturing method, not only the particle diameter of the colorant particles contained in the obtained color toner is reduced, but also the uniformity of the dispersion state of the particles is increased, so that the reproducibility of the color of the projected image by OHP is further improved. It gets even better.
Furthermore, since a release agent that is incompatible with the binder resin is dispersed in the binder resin, the release agent oozes out from the toner surface during fixing, and even when oil is not applied to the fixing member, Sufficient offset resistance. Here, when the release agent is compatible with the binder resin, the exfoliating effect of the release agent at the time of fixing is lost, and offset is likely to occur.
[0012]
The softening point of the binder resin used in the toner of the present invention is preferably 80 to 110 ° C. This is because by using a binder resin with a softening point of 80-110 ° C., the toner has a low viscosity at the time of fixing, and sufficient melting occurs, so it is possible to obtain excellent gloss, transparency, and color reproducibility. In addition, a decrease in cohesion between molecules is less likely to occur, and offset is less likely to occur.
When the softening point of the binder resin is lower than the above temperature range, offset is likely to occur, and further, blocking is likely to occur during storage of the toner. On the other hand, when the temperature is higher than the above temperature range, gloss and transparency are insufficient.
The softening point of the binder resin was measured as follows. That is, using an elevated flow tester (CFT-500) (manufactured by Shimadzu Corporation), the diameter of the pore of the die is 1 mm, and the pressure is 20 kg / cm. ² 1 cm under the condition of a heating rate of 6 ° C./min ³ The temperature corresponding to 1/2 the height from the outflow start point to the outflow end point when the sample was melted out was taken as the softening point.
[0013]
As the binder resin used in the toner of the present invention, a polyester resin or a polyol resin, or a mixture of a polyester resin and a polyol resin is particularly preferable because of excellent gloss, transparency, and offset resistance. However, when two or more different types of binder resins are used, it is preferable that these resins are compatible with each other during kneading, and when there is an interface between the resins without being compatible, light refraction is In many cases, the transparency deteriorates.
Here, the compatibility state of the binder resins and the dispersion state of the release agent in the binder resin can be confirmed using a transmission electron microscope, and the definitions of compatible and incompatible in the present invention. Is based on an enlarged photograph at a magnification of 100,000 times using a transmission electron microscope.
[0014]
Although various types of polyester resins can be used, the following are particularly preferable as those used in the present invention.
(A) The following general formula (I)
[Chemical 1]

(In the previous formula, R ¹ And R ² May be the same or different and is an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the average value of the sum is 2 to 2
16. )
And (b) a polyester resin obtained by condensation polymerization of a component selected from the group consisting of a divalent or higher polyvalent carboxylic acid, its anhydride and its lower alkyl ester.
[0015]
Examples of the diol represented by the general formula (I) include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyester (2) -2,2-bis ( 4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (16) -2,2-bis (4-hydroxyphenyl) propane and the like. . In addition, about 5 mol% or less of polyhydroxy compounds having two or more functional groups as described below can be used for the diol component. Ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or etherified polyhydroxyl compounds thereof.
[0016]
Specific examples of (b) include phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid and anhydrides thereof, and lower alkyl esters thereof, trimellitic acid or anhydrides thereof. Examples thereof include succinic acid derivatives such as acid, n-dodecenyl succinic acid, n-dodecyl succinic acid, n-butyl succinic acid, iso-dodecenyl succinic acid, and iso-octyl succinic acid. In particular, by introducing these succinic acid derivatives, the fixing property at a low temperature as a toner becomes sufficient, and the glossiness is further improved.
The polyester resin can be usually produced by polycondensing the polyol component and the polyvalent carboxylic acid component at a temperature of 180 to 250 ° C. in an inert gas atmosphere.
[0017]
As the polyol resin, various types can be used, and in the present invention, in particular, as the polyol resin, (a) an epoxy resin, (b) an alkylene oxide adduct of a dihydric phenol or a glycidiether thereof, It is preferable to use a polyol formed by reacting (c) a compound having one active hydrogen reacting with an epoxy group in the molecule and (d) a compound having two or more active hydrogens reacting with an epoxy group in the molecule. .
Furthermore, the epoxy resin (a) is particularly preferably at least two or more bisphenol A type epoxy resins having different number average molecular weights. In this case, the polyol resin imparts good gloss and transparency, and is effective in offset resistance. The epoxy resin used in the present invention is preferably obtained by binding bisphenol such as bisphenol A or bisphenol F and epichlorohydrin.
The epoxy resin is at least two or more bisphenol A type epoxy resins having different number average molecular weights in order to obtain stable fixing characteristics and gloss. The low molecular weight component has a number average molecular weight of 360 to 2000, and has a high molecular weight component. The number average molecular weight is preferably 3000 to 10,000. Further, the low molecular weight component is preferably 20 to 50% by weight, and the high molecular weight component is preferably 5 to 40% by weight. When there are too many low molecular weight components, or when the molecular weight is lower than 360, there is a possibility that the gloss will be too high or the storage stability may be deteriorated. Further, when the amount of the high molecular weight component is too large, or when the molecular weight is higher than 10,000, the gloss may be insufficient or the fixability may be deteriorated.
[0018]
Examples of the (b) dihydric phenol alkylene oxide adduct include the following. That is, reaction products of ethylene oxide, propylene oxide, butylene oxide and mixtures thereof with bisphenols such as bisphenol A and bisphenol F can be mentioned. The resulting adduct may be used after glycidylation with epichlorohydrin or β-methylepichlorohydrin. In particular, diglycidyl ether of an alkyl oxide adduct of bisphenol A represented by the following general formula (II) is preferable.
[Chemical 2]

Where R is —CH ₂ -CH ₂ -, -CH ₂ -CH (CH ₃ )-Or -CH ₂ -CH ₂ -CH ₂ -Group, and n and m are the number of repeating units, each being 1 or more, and n + m = 2 to 6. )
The alkylene oxide adduct or glycidyl ether of the dihydric phenol is preferably contained in an amount of 10 to 40% by weight based on the polyol resin. Here, when the amount is small, problems such as an increase in curl occur, and when n + m is 7 or more, or when the amount is too large, gloss may be excessively produced, and further, storage stability may be deteriorated.
[0019]
Examples of the compound (c) having one active hydrogen that reacts with the epoxy group in the molecule include monohydric phenols, secondary amines, and carboxylic acids. The following are illustrated as monohydric phenols. That is, phenol, cresol, isopropylphenol, aminophenol, nonylphenol, dodecylphenol, xylenol, p-cumylphenol and the like can be mentioned. Secondary amines include diethylamine, dipropylamine, dibutylamine, N-methyl (ethyl) piperazine, piperidine and the like. Examples of carboxylic acids include propionic acid and caproic acid.
[0020]
Examples of the compound (d) having two or more active hydrogens that react with the epoxy group in the molecule include dihydric phenols, polyhydric phenols, and polycarboxylic acids. Examples of the dihydric phenol include bisphenols such as bisphenol A and bisphenol F. Examples of polyphenols include orthocresol novolaks, phenol novolaks, tris (4-hydroxyphenyl) methane, and 1- [α-methyl-α- (4-hydroxyphenyl) ethyl] benzene. Examples of the polyvalent carboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, trimet acid, and trimellitic anhydride.
[0021]
In order to obtain a polyol resin having an epoxy resin part and an alkylene oxide part in the main chain of the present invention, various raw materials can be combined. For example, it can be obtained by reacting an epoxy resin having a glycidyl group at both ends and an alkylene oxide adduct of a dihydric phenol having both glycidyl groups with a dihalide, diisocyanate, diamine, dioctyl, polyhydric phenol, or dicarboxylic acid. Among these, it is most preferable to react divalent phenol from the viewpoint of reaction stability. Moreover, it is also preferable to use polyhydric phenols and polyhydric carboxylic acids in combination with dihydric phenols as long as they do not gel. Here, the amount of polyphenols and polycarboxylic acids is 15% or less, preferably 10% or less, based on the total amount.
When the polyester resin or polyol resin has a high crosslink density, it becomes difficult to obtain transparency and glossiness, and it is preferably non-crosslinked or weakly crosslinked (THF insoluble content is 5% or less).
[0022]
As the binder resin, in addition to the polyester resin and polyol resin, the following resins may be used as necessary. Styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, and substituted polymers thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinyl Naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, Styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl Ether copolymer, styrene Nylmethyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, etc. Copolymer: Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyurethane, polyamide, epoxy resin, polyvinyl butyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin etc.
[0023]
As the colorant, a dye / pigment capable of obtaining yellow, magenta, cyan, and black toners can be used. For example, carbon black, lamp black, aniline black, ultramarine, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, lake, chalcoil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane series Any conventionally known dyes and pigments such as dyes such as dyes can be used singly or in combination. In particular, the colorant used for yellow toner includes C.I. I. Pigment Yellow 180 is preferably used. This colorant has particularly strong cohesiveness, and the usual aggregation method of the toner, that is, a method of melt-kneading the binder resin, the colorant and the charge control agent cannot solve the strong aggregation state of the colorant. . For this reason, the dispersion diameter of the colorant particles in the obtained toner particles is large. Therefore, the transparency of the toner is also deteriorated, and only the color reproducibility which is an important quality of the color toner is obtained. However, according to the production method of the present invention, the aggregated colorant particles can be sufficiently unraveled, and a toner having excellent transparency can be obtained. By using the colorant of the present invention, there is no peeling of the colorant from the toner surface even after long-term use, preventing contamination of the carrier surface in the two-component developer, filming on the developing roller in one-component development, etc. Furthermore, it has become clear that filming on the fixing member is prevented.
[0024]
The colorant used for the magenta toner includes C.I. I. It is preferable to use Pigment Red 122 because it has a wider color reproduction range than other magenta colorants. However, this colorant is also a yellow colorant C.I. I. Similar to Pigment Yellow 180, this colorant is particularly strong in cohesion, and in a normal toner manufacturing method, that is, a method of melt-kneading a binder resin and a colorant or other materials such as a charge control agent as required. It is impossible to solve the strong aggregation state. For this reason, the dispersion diameter of the colorant particles in the obtained toner particles is large. Therefore, the transparency of the toner is also deteriorated, and only the color reproducibility which is an important quality of the color toner is obtained. However, with the production method of the present invention, the agglomerated colorant particles can be sufficiently unwound and a toner having excellent transparency can be obtained. By using this colorant, there is no peeling of the colorant from the toner surface even after long-term use, preventing contamination of the carrier surface in the two-component developer, filming on the developing roller in one-component development, etc. It was also found that filming on the fixing member is prevented.
The content of these colorants is usually 1 to 30 parts by weight, preferably 3 to 20 parts by weight with respect to 100 parts by weight of the binder resin.
[0025]
The release agent used in the toner of the present invention is one having an average dispersed particle size of 0.1 to 3 μm in the toner. Even when not coated, the film has sufficient offset resistance. In addition, when the average dispersed particle size of the release agent in the toner is smaller than 0.1 μm, a sufficient exudation effect of the release agent at the time of fixing is weak and sufficient offset resistance may not be obtained. On the other hand, if it is larger than 3 μm, the charging characteristics may be deteriorated due to a decrease in fluidity of the toner or contamination of the carrier surface due to desorption from the toner surface. The average dispersed particle diameter of the release agent in the toner can be confirmed by a transmission electron microscope, and this definition in the present invention is that the release agent portion 100 randomly selected by an enlarged photograph at a magnification of 100,000 times. It is the average of the points.
[0026]
The melting point of the release agent used in the toner of the present invention is particularly preferably 75 to 100 ° C. If it is lower than this range, offset is likely to occur, and further, blocking is likely to occur during storage of the toner. Conversely, if it is high, sufficient fixability may not be obtained.
Here, the melting point of the release agent was measured as follows. The melting point was measured with a melting point measuring instrument (Rigaku THERMOFLEX TG8110 type) manufactured by Rigaku Corporation under the condition of a heating rate of 10 ° C./min, and the main maximum peak of the endothermic curve was taken as the melting point.
[0027]
It is preferable that Mw / Mn which is a ratio of the weight average molecular weight Mw and the number average molecular weight Mn is 1.0 to 1.2. The reason is not sufficiently clear, but by setting Mw / Mn to 1.0 to 1.2, exudation of the release agent at the time of fixing is performed efficiently, so that sufficient offset resistance is obtained. It is thought that
The molecular weight of the release agent was measured as follows.
Molecular weight measurement by GPC
The column was stabilized in a constant temperature bath at 40 ° C., THF was flowed as an eluent at a flow rate of 1 ml / min, and 200 μl of a sample THF solution adjusted to a sample temperature of 0.05 to 0.5 parts by weight was injected for measurement. Do. The molecular weight of the sample was calculated from the molecular weight distribution determined from the retention time based on a calibration curve prepared in advance. The calibration curve at this time was prepared using several types of monodisperse polystyrene as standard samples. Analytical column: Excel pak SEC-G14 / G16 / G18 [manufactured by Yokogawa Analytical Systems Co., Ltd.].
[0028]
The release agent used in the toner of the present invention can be any material as long as it is incompatible with the binder resin. In particular, ester or olefin wax is used as the release agent. preferable. Since these release agents are more uniformly dispersed in the binder resin, they exhibit excellent offset resistance, and are particularly effective when a polyester resin or a polyol resin is used as the binder resin.
Here, the ester wax means a wax having an ester bond, and examples thereof include natural waxes such as candelilla wax, carnauba wax, rice wax, and the like, and olefin waxes include polyethylene wax and polypropylene. Examples thereof include wax and Fischer-Tropsch wax. The content of these release agents is usually 1 to 20 parts by weight, preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
[0029]
The toner of the present invention preferably contains a charge control agent in order to impart appropriate charge to the toner. The charge control agent in this case is preferably one that can add a white material from a transparent color that does not impair the color tone of the color toner, and can stabilize and impart toner chargeability to negative polarity or positive polarity. Of these, the addition of a metal salt of a salicylic acid derivative is particularly effective in stabilizing toner chargeability to the negative polarity.
Examples of the metal salt of the salicylic acid derivative used here include compounds represented by the following general formula (III).
[Chemical 3]

(Wherein R ¹ , R ² , R ³ And R ⁴ Represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an allyl group, and particularly preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an allyl group. Where R ¹ , R ² , R ³ And R ⁴ May be the same or different at the same time. Me represents any metal selected from zinc, nickel, cobalt, copper, and chromium. )
[0030]
The metal salt of the salicylic acid derivative is described in CLARK, J. et al. L Kao, H (1948) J. MoI. Amer. Chem. Soc. 70, 2151 can be easily included. For example, 2 mol of salicylic acid sodium salt (including the sodium salt of a salicylic acid derivative) and 1 mol of zinc chloride are added to a solvent, mixed, heated and stirred to obtain a zinc salt. . This metal salt is a white-colored crystal and does not show coloring when dispersed in toner. A metal salt other than a zinc salt can also be produced according to the above method. Specific examples of particularly preferred compounds among the metal salts of salicylic acid derivatives are shown in the following formulas (1) to (8).
[Formula 4]

The metal salt of the salicylic acid derivative has good dispersibility with respect to the binder resin, and is difficult to film on the phenomenon roller. In particular, the content of the metal salt of the salicylic acid derivative is preferably 0.5 to 8 parts by weight with respect to 100 parts by weight of the binder resin.
[0031]
The color toner for electrophotography of the present invention is produced by the following novel method. That is, the binder resin and the colorant mixture are kneaded in advance with an organic solvent at a temperature lower than the melting temperature of the binder resin, and the binder resin and the binder resin are incompatible with each other. The mold material or other materials such as a charge control agent as required are added, heated and kneaded in the second stage, and then pulverized to produce the electrophotographic color toner of the present invention. At this time, the first-stage kneading is performed in a state where the organic solvent added to the first-stage kneaded product is contained in an amount of 5 to 15 parts by weight with respect to 100 parts by weight of (binder resin + colorant). This is effective for increasing the transparency of the toner.
Moreover, the binder resin and the colorant added in the first and second stages are preferably 80:20 to 20:80, more preferably 70:30 to 40:60, in weight ratio.
This is because, by using an organic solvent, the binder resin and the colorant are initially sufficiently adhered to each other so that the dispersion can be effectively performed, and is lower than the melting temperature of the binder resin. Since the kneading is performed at a temperature, the viscosity of the kneaded product is very high, and the shearing force works strongly, the dispersion of the colorant in the binder resin is improved, and thereby the dispersion diameter of the colorant is reduced, It is considered that transparency and color reproducibility are excellent and a high degree of coloring can be obtained.
As a specific method, for example, a binder resin, a colorant, and an organic solvent are mixed with a blender such as a super mixer, and the obtained mixture is then combined with a kneader such as a two-roll or three-roll. A sample is obtained by kneading at a temperature lower than the melting temperature of the resin. Moreover, as an organic solvent, a general thing can be used, considering the solubility with a binder resin, However, Acetone, toluene, a butanone, etc. are especially preferable from the surface of the dispersibility of a coloring agent.
According to this new production method, not only the particle size of the colorant particles contained in the obtained color toner is reduced, but also the uniformity of the dispersion state of the particles is increased, so that the color reproducibility of the projected image by OHP is improved. It is a factor that makes it even better.
[0032]
The particle diameter of the color toner for electrophotography of the present invention is preferably 3 to 10 μm in terms of volume average particle diameter. If the particle diameter is smaller than this, it may cause scumming or develop fluidity during development. It may worsen and impair toner supply and cleaning properties. When the particle size is larger than this, there may be a problem such as dust in the image or deterioration of resolution.
Further, as an external additive, silica, titanium oxide, alumina or the like can be added for the purpose of improving the fluidity of the toner. If necessary, a fatty acid metal salt (such as zinc stearate or aluminum stearate), polyvinylidene fluoride, or the like may be added.
[0033]
The color toner for electrophotography of the present invention can be applied to both one-component toner and two-component toner. When used as a two-component toner, it is used by mixing with a carrier. As the carrier that can be used in the present invention, for example, known powders such as iron powder, ferrite powder, nickel powder, glass beads, and the like can be used, but these surfaces are coated with a resin or the like. It is preferable to do.
In this case, the resin used is polyfluorinated carbon, polyvinyl chloride, polyvinylidene chloride, phenol resin, polyvinyl acetal, acrylic resin, silicone resin, or the like.
As a method for forming the resin layer, a resin may be applied to the surface of the carrier by means of a spraying method, a dipping method, or the like, as in the past.
Here, the average particle diameter of these carriers is usually 10 to 100 μm, preferably 30 to 60 μm. The amount of resin used is usually 1 to 10 parts by weight with respect to 100 parts by weight of the carrier.
Further, the mixing ratio of the toner and the carrier is generally about 0.5 to 7.0 parts by weight with respect to 100 parts by weight of the carrier.
The electrophotographic color toner of the present invention is preferably a full color composed of at least yellow, magenta and cyan toners.
[0034]
【Example】
Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited to these. In addition, the part in an Example represents a weight part.
[0035]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0036]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.1 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0037]

Were sufficiently mixed with a blender, and then melt kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.7 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0038]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0039]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0040]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.6 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0041]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.7 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and mixed with a Henschel mixer to obtain the toner of the present invention.
[0042]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle size of 7.3 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0043]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.4 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0044]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.4 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0045]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0046]

Were sufficiently mixed with a blender, and then melt kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.2 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0047]

After being sufficiently mixed with a blender, the mixture was melt-kneaded in a biaxial kneader heated to 100 ° C. The kneaded product was cooled with water, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0048]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.8 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0049]

Were sufficiently mixed with a blender, and then melt kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.4 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0050]

After being sufficiently mixed with a blender, it was melt-kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.2 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0051]

Were sufficiently mixed with a blender, and then melt kneaded in a biaxial kneader heated to 140 ° C. The kneaded product was cooled with water, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base colored particles, and the mixture was mixed with a Henschel mixer to obtain the toner of the present invention.
[0052]
Comparative Example 1 This is an example in which a composition obtained by kneading a binder resin and a colorant together with an organic solvent at a temperature lower than the melting temperature of the binder resin is not used.

After being sufficiently mixed with a blender, the mixture was melt-kneaded in a biaxial kneader heated to 100 ° C. The kneaded product was cooled with water, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base coloring particles, and the mixture was mixed with a Henschel mixer to obtain a toner.
[0053]
Comparative Example 2
This comparative example is an example where the binder resin and the release agent are compatible.

After being sufficiently mixed with a blender, the mixture was melt-kneaded in a biaxial kneader heated to 100 ° C. The kneaded product was cooled with water, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.5 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base coloring particles, and the mixture was mixed with a Henschel mixer to obtain a toner.
[0054]
Comparative Example 3
This comparative example is an example in which no organic solvent is added when the binder resin and the colorant are kneaded at a temperature lower than the melting temperature of the binder resin.

After being sufficiently mixed with a blender, the mixture was melt-kneaded in a biaxial kneader heated to 100 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.2 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base coloring particles, and the mixture was mixed with a Henschel mixer to obtain a toner.
[0055]
Comparative Example 4
This is an example in which the kneading operation in which the binder resin and the colorant are previously performed with an organic solvent is performed at a temperature higher than the melting temperature of the binder resin.

After being sufficiently mixed with a blender, the mixture was melt-kneaded in a biaxial kneader heated to 100 ° C. The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then a matrix colored particle having a volume average particle diameter of 7.8 μm was obtained using an air classifier.
Further, 0.75 parts by weight of hydrophobic silica was added to 100 parts of the base coloring particles, and the mixture was mixed with a Henschel mixer to obtain a toner.
[0056]

Was coated with 1.2 parts by weight of the core material using a fluidized bed, and further calcined at 210 ° C. for 2 hours to obtain a carrier coated with the resin.
Creating a developer
5 parts of each of the toners obtained in Examples 1 to 17 and Comparative Examples 1 to 4 and 95 parts of the carrier were mixed with a tumbler mixer to obtain a developer.
The obtained developer has a fixing device composed of a fixing roller composed of a silicon roller having an outer diameter of 60 mm with a built-in heater and a pressure roller composed of a Teflon tube-covered silicon roller having an outer diameter of 60 mm, and the fixing device It was set in a full-color copying machine (PRETER 550, manufactured by Ricoh) (FIG. 1) from which the oil application mechanism of the apparatus was removed, and the following various evaluations were performed.
[0057]
Evaluation 1: Fixing temperature range
Using the above-mentioned full-color copying machine (PRETER550, manufactured by Ricoh), the amount of adhesion consisting of any one of yellow, magenta, and cyan is 1.0 ± 0. 1mg / cm ² A solid image was prepared and adjusted so that the temperature of the fixing member was variable under the following fixing conditions, and the temperature at which no offset occurred was measured. The results at this time are shown in Table 1.
Fixing machine linear speed: 180 ± 2 mm / sec.
Fixing nip width: 10 ± 1 mm
Evaluation 2: Glossiness
In the above monochromatic image sample, the glossiness of the sample when the fixing member surface temperature is 160 ° C. was measured at an incident angle of 60 ° with a gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. Glossiness comes out. As a full-color copy image, moderate gloss is preferred, and about 15 to 30% is preferable. The results at this time are shown in Table 1.
Evaluation 3: Haze degree
Using an OHP sheet (TYPE PPC-DX, manufactured by Ricoh Elemex Co., Ltd.) with the above monochromatic image sample as transfer paper, the haze degree of the sample when the fixing member surface temperature is 160 ° C. is a direct reading haze computer HGM of Suga Test Instruments Co., Ltd. -2DP type. This degree of haze is also called haze, and is measured as a measure of the transparency of the toner. The lower the value, the higher the transparency and the better the color developability when using OHP paper. The haze value indicating good color developability is preferably 25% or less. The results at this time are shown in Table 1.
In addition, the following evaluations were performed on the toners of Examples and Comparative Examples.
Evaluation 4: Dispersing agent dispersion diameter in toner
The dispersion diameter of the release agent in the toner is measured by various methods. Here, an ultrathin section of the toner is prepared, and the toner is measured using a transmission electron microscope (H-9000H manufactured by Hitachi, Ltd.). This was done by taking a cross-sectional photograph (magnification x 100,000). From this photograph, an average value was obtained from the dispersion diameter of 100 randomly selected release parts. Here, the dispersion diameter of one particle is the average of the longest diameter and the shortest diameter, and the aggregates are those in which the aggregate itself is one particle. Table 1 shows the results at this time.
[0058]
[Table 1]

[0059]
【The invention's effect】
According to the present invention, a color toner containing a release agent is excellent in transparency and color reproducibility, has a high degree of coloring, and has appropriate glossiness, good fixability, and sufficient offset resistance. In addition, an electrophotographic color toner that can be applied to a fixing device that does not use oil as a fixing member and a method for manufacturing the same are provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a full-color copying machine (PRETER 550, manufactured by Ricoh) used in Examples and Comparative Examples.
[Explanation of symbols]
101 scanner
112 printer
201 copier
202 Black development unit
203 Cyan development unit
204 Magenta development unit
205 Yellow development unit
206 Intermediate transfer belt
207 Charging device
208 Laser optical system
209 Contact glass
210 Exposure lamp (halogen lamp)
211 reflection mirror
212 Imaging lens
213 CCD image sensor
214 Cleaning device
215 photoconductor
216 Paper feed unit
217 Transfer bias roller
218 Conveyor belt
219 Fixing device
220 Output tray
221 Bias roller
222 Belt cleaning device

Claims (9)

A granular composition obtained by kneading the binder resin and the colorant together with an organic solvent in advance at the first stage at a temperature lower than the melting temperature of the binder resin is added to the binder resin and the binder resin. An electrophotographic color toner obtained by mixing an incompatible release agent and performing heat-melt kneading (second-stage kneading), wherein the binder resin comprises a polyol resin and a polyester resin. An electrophotographic color toner, wherein the color toner is at least one resin selected from the group consisting of:   The color toner for electrophotography according to claim 1, wherein the binder resin has a softening point of 80 to 110 ° C. Yellow toner is C.I. I. The color toner for electrophotography according to claim 1, which is Pigment Yellow 180. The magenta toner is C.I. I. The color toner for electrophotography according to claim 1, which is Pigment Red 122. The electrophotographic color toner according to any one of claims 1 to 4, wherein an average dispersed particle diameter of the release agent in the toner is 0.1 to 3 µm. The color toner for electrophotography according to claim 1, wherein the releasing agent has a melting point of 75 to 100 ° C. The color toner for electrophotography according to any one of claims 1 to 6, wherein Mw / Mn, which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the release agent, is 1.0 to 1.2. . The color toner for electrophotography according to any one of claims 1 to 7, wherein a salicylic acid derivative metal salt is used in combination as a charge control agent. The mixture of the binder resin and the colorant is kneaded with the organic solvent in advance at a temperature lower than the melting temperature of the binder resin (first stage kneading), and further, the binder resin and the binder resin are incompatible with each other. A method for producing a color toner for electrophotography in which a release agent or, if necessary, other materials usually used in the production of a color toner is added and heat melting and kneading (second stage kneading) is performed, the binding Using at least one resin selected from the group consisting of a polyol resin and a polyester resin as a resin, using a pigment as the colorant, and relative to the total amount (100 parts by weight) of the binder resin and the colorant A method for producing a color toner for electrophotography, wherein the first stage kneading is carried out in a state where 5 to 15 parts by weight of an organic solvent is contained .

Images