JP4485100B2 - Electrophotographic photoreceptor - Google Patents

Description

(但し、上記一般式１において、Ｒ¹は水素原子、ハロゲン原子、アルキル基、アルコキシ基又はシアノ基を、Ａはカップラー残基を表す。)
【００１７】
（２）上記一般式（１）のトリスアゾ化合物におけるカップラー残基Ａが下記一般式（２）〜（７）で表される残基から選ばれたものであることを特徴とする上記（１）記載の電子写真用感光体。
【００１８】
【化２２】

【００１９】
〔但し、上式中Ｘ¹、Ｙ¹及びＺはそれぞれ以下のものを表わす。Ｘ¹：−ＯＨ、−Ｎ（Ｒ²）（Ｒ³）又は、−ＮＨＳＯ₂−Ｒ⁴。（Ｒ²及びＲ³は水素原子、アシル基又は置換若しくは無置換のアルキル基を表わし、Ｒ⁴は置換若しくは無置換のアルキル基又は置換若しくは無置換のアリール基を表わす。）Ｙ¹：水素原子、ハロゲン原子、置換若しくは無置換のアルキル基、アルコキシ基、カルボキシ基、スルホン基、ベンズイミダゾリル基、置換若しくは無置換のスルファモイル基、置換若しくは無置換のアロファノイル基又は−ＣＯＮ（Ｒ⁵）（Ｙ²）を表わす。｛Ｒ⁵は水素原子、アルキル基若しくはその置換体又はフェニル基若しくはその置換体を表わし、Ｙ²は炭化水素環基若しくはその置換体、複素環基若しくはその置換体、又は−Ｎ＝Ｃ（Ｒ⁶）（Ｒ⁷）（但し、Ｒ⁶は炭化水素環基若しくはその置換体、複素環基若しくはその置換体又はスチリル基若しくはその置換体、Ｒ⁷は水素原子、アルキル基若しくはその置換体又はフェニル基若しくはその置換体を表わすか、あるいはＲ6及びＲ7はそれらに結合する炭素原子と共に環を形成してもよい）を示す。｝Ｚ：炭化水素環基若しくはその置換体又は複素環基若しくはその置換体。〕
【００２０】
【化２３】

（上式中、Ｒ⁸は置換又は無置換の炭化水素基を表わす。）
【００２１】
【化２４】

（上式中、Ｒ⁹は置換又は無置換の炭化水素基を表わす。）
【００２２】
【化２５】

（上式中Ｒ¹⁰はアルキル基、カルバモイル基、カルボキシル基又はそのエステルを表わし、またＡｒ¹は置換又は無置換の芳香族炭化水素基を表わす。）
【００２３】
【化２６】

（上式中、Ｘ²は芳香族炭化水素の２価基又は複素環の２価基を表わす。）
【００２４】
【化２７】

（上式中、Ｘ²は芳香族炭化水素の２価基又は複素環の２価基を表わす。）
【００２５】
（３）前記トリスアゾ化合物が下式（８）で表される化合物であることを特徴とする上記（１）に記載の電子写真用感光体。
【００２６】
【化２８】

【００２７】
（４）導電性支持体上に少なくとも電荷発生材料と電荷輸送材料を含む電子写真用感光体において、その最表層がコア/シェル構造を有するグラフト共重合体の粒子を含有し、前記電荷発生材料が下記一般式（９）で表されるビスアゾ化合物であり、前記コア／シェル構造を有するグラフト共重合体の粒子は、アクリル−シリコーン複合ゴム状重合体に１種または２種以上のビニル単量体をラジカル重合技術によって一段で、あるいは多段で重合されてなるものであることを特徴とする電子写真用感光体。
【００２８】
【化２９】

（式中、Ｒ^１１及びＲ^１２は水素原子、ハロゲン原子、置換または無置換のアルキル基、置換または無置換のアルコキシ基、シアノ基またはニトロ基を表しそれぞれ同一でも異なっていてもよい。BとCはカップラー残基を示し同一でも異なっていても良い。具体的には請求項２で示したカップラー残基Ａと同様に定義される。）
【００２９】
（５）前記ビスアゾ化合物が下式（１０）で表されるビスアゾ化合物であることを特徴とする上記（４）に記載の電子写真用感光体。
【００３０】
【化３０】

【００３１】
（６）前記ビスアゾ化合物が下式（１１）で表されるビスアゾ化合物であることを特徴とする上記（４）に記載の電子写真用感光体。
【００３２】
【化３１】

【００３３】
（７）導電性支持体上に少なくとも電荷発生材料と電荷輸送材料を含む電子写真用感光体において、その最表層がコア/シェル構造を有するグラフト共重合体の粒子を含有し、前記電荷発生材料が下記一般式（１２）で表されるビスアゾ化合物であり、前記コア／シェル構造を有するグラフト共重合体の粒子は、アクリル−シリコーン複合ゴム状重合体に１種または２種以上のビニル単量体をラジカル重合技術によって一段で、あるいは多段で重合されてなるものであることを特徴とする電子写真用感光体。
【化３２】

（式中、ＤとＥはカップラー残基を示し同一でも異なっていても良い。具体的には上記（２）で示したカップラー残基Ａと同様に定義される。）
【００３４】
（８）前記ビスアゾ化合物が下式（１３）で表されるビスアゾ化合物であることを特徴とする上記（７）に記載の電子写真用感光体。
【化３３】

【００３５】
（９）導電性支持体上に少なくとも電荷発生材料と電荷輸送材料を含む電子写真用感光体において、その最表層がコア/シェル構造を有するグラフト共重合体の粒子を含有し、前記電荷発生材料が下記一般式（１４）で表されるフタロシアニン化合物であり、前記コア／シェル構造を有するグラフト共重合体の粒子は、アクリル−シリコーン複合ゴム状重合体に１種または２種以上のビニル単量体をラジカル重合技術によって一段で、あるいは多段で重合されてなるものであることを特徴とする電子写真用感光体。
【化３４】

［式中Ｍは金属を表すか、金属が存在しない場合には二つの水素原子を表す。］
【００３６】
（１０）導電性支持体上に少なくとも電荷発生材料と電荷輸送材料を含む電子写真用感光体において、その最表層がコア/シェル構造を有するグラフト共重合体の粒子を含有し、前記電荷発生材料が上下記一般式（１）、（９）、（１２）及び（１４）で表される化合物の2種以上の混合物であり、前記コア／シェル構造を有するグラフト共重合体の粒子は、アクリル−シリコーン複合ゴム状重合体に１種または２種以上のビニル単量体をラジカル重合技術によって一段で、あるいは多段で重合されてなるものであることを特徴とする電子写真用感光体。
【化２１】

(但し、上記一般式１において、Ｒ ¹ は水素原子、ハロゲン原子、アルキル基、アルコキシ基又はシアノ基を、Ａはカップラー残基を表す。)
【化２９】

（式中、Ｒ ^１１ 及びＲ ^１２ は水素原子、ハロゲン原子、置換または無置換のアルキル基、置換または無置換のアルコキシ基、シアノ基またはニトロ基を表しそれぞれ同一でも異なっていてもよい。BとCはカップラー残基を示し同一でも異なっていても良い。具体的には請求項２で示したカップラー残基Ａと同様に定義される。）
【化３２】

（式中、ＤとＥはカップラー残基を示し同一でも異なっていても良い。具体的には請求項２で示したカップラー残基Ａと同様に定義される。）
【化３４】

［式中Ｍは金属を表すか、金属が存在しない場合には二つの水素原子を表す。］
【００３７】
（１１）導電性支持体上に少なくとも電荷発生材料と電荷輸送材料を含む電子写真用感光体において、その最表層がコア/シェル構造を有するグラフト共重合体の粒子を含有し、前記電荷輸送材料が下記一般式（１５）で表されるα-フェニルスチルベン誘導体であり、前記コア／シェル構造を有するグラフト共重合体の粒子は、アクリル−シリコーン複合ゴム状重合体に１種または２種以上のビニル単量体をラジカル重合技術によって一段で、あるいは多段で重合されてなるものであることを特徴とする電子写真用感光体。
【００３８】
【化３５】

【００３９】
（式中、ｎは０または１の整数、Ar⁵及びAr⁶は、置換もしくは未置換のアリール基[但し、同時に無置換フェニル基の場合は除く]、又は共同して環を形成する基を表わし、Ar⁷は、置換もしくは未置換のアリール基を表し、 Ｒ¹⁶、R¹⁷及びR¹⁸は水素原子、置換もしくは無置換のアルキル基または置換もしくは無置換のアリール基を表し、上記アリール基及びアリーレン基の置換基は、アルコキシ基、フェノキシ基、アルキル基、ヒドロキシ基、ハロゲン原子、シアノ基、またはニトロ基である。）
【００４０】
（１２）前記α-フェニルスチルベン誘導体が、下記一般式（１６）で表されるα-フェニルスチルベン誘導体であることを特徴とする上記（１１）に記載の電子写真用感光体。
【００４１】
【化３６】

（式中、R¹⁹は水素原子、アルキル基、アルコキシ基、又はハロゲン原子を示す。）
【００４２】
（１３）導電性支持体上に少なくとも電荷発生材料と電荷輸送材料を含む電子写真用感光体において、その最表層がコア/シェル構造を有するグラフト共重合体の粒子を含有し、前記電荷輸送材料が下記一般式（１７）で表されるベンジジン化合物であり、前記コア／シェル構造を有するグラフト共重合体の粒子は、アクリル−シリコーン複合ゴム状重合体に１種または２種以上のビニル単量体をラジカル重合技術によって一段で、あるいは多段で重合されてなるものであることを特徴とする電子写真用感光体。
【００４３】
【化３７】

（式中、Ｒ²⁰は低級アルキル基、低級アルコキシ基またはハロゲン原子を表し、Ｒ²¹、Ｒ²²は同じでも異なっていてもよく、水素原子、低級アルキル基、低級アルコキシ基またはハロゲン原子を表し、ｈ、ｌ、ｍは０〜４の整数を表す。）
【００４４】
（１４）導電性支持体上に少なくとも電荷発生材料と電荷輸送材料を含む電子写真用感光体において、その最表層がコア/シェル構造を有するグラフト共重合体の粒子を含有し、前記電荷輸送性材料が、下記一般式（１８）で表されるトリアリールアミン構造を有する電荷輸送性高分子であり、前記コア／シェル構造を有するグラフト共重合体の粒子は、アクリル−シリコーン複合ゴム状重合体に１種または２種以上のビニル単量体をラジカル重合技術によって一段で、あるいは多段で重合されてなるものであることを特徴とする電子写真用感光体。
【００４５】
【化３８】

【００４６】
[式中、 Ａｒ¹、Ａｒ²、Ａｒ³は置換もしくは無置換のアリレン基を表す。Ｒ¹、Ｒ²は同一又は異なるアシル基、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基を表す。ｋは５〜５０００の整数、ｊは５〜５０００の整数であり、0＜k/(k + j)≦1。Ｘは置換または無置換の脂肪族2価基、置換または無置換環状脂肪族2価基、置換または無置換芳香族2価基、又はこれらを連結してできる2価基、又は、下記式で表されるものを示す。］
【００４７】
【化３９】

【００４８】
（ここで、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶ は独立して置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基またはハロゲン原子である。またa及びbは各々独立して0〜4の整数であり、c及びdは各々独立して0〜3の整数であり、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶がそれぞれに複数個存在するときは同一でも異なっていても良い。Ｙは単結合、炭素原子数2〜12の直鎖状のアルキレン基、置換もしくは無置換の炭素原子数3〜12の分岐状のアルキレン基、一つ以上の炭素数１〜10のアルキレン基と一つ以上の酸素原子及び硫黄原子から構成される２価基、-O-、-S-、-SO-、-SO₂-、-CO-、-COO-、又は
【００４９】
【化４０】

【００５０】
から選ばれ、Ｚ¹、Ｚ²は置換もしくは無置換の脂肪族の2価基又は置換もしくは無置換のアリレン基を表し、 Ｒ⁷、Ｒ¹⁴はハロゲン原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアルコキシ基、置換もしくは無置換のアリール基を表し、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹、Ｒ¹²、Ｒ¹³は各々独立して水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアルコキシ基、置換もしくは無置換のアリール基を表す。またＲ⁸とＲ⁹は結合して炭素数５〜12の炭素環を形成してもよく、Ｒ¹⁵とＲ¹⁶は単結合または炭素数1〜4のアルキレン基を表し、Ｒ¹⁷とＲ¹⁸は各々独立して置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基を表し、ｅとｇは0〜4の整数、ｆは１又は２、ｈは0〜20の整数、ｉは0〜2000の整数を表す。）
【００５１】
【発明の実施の態様】
以下に詳細に本発明において用いられるコア/シェル構造を有するグラフト共重合体（以下、「コア/シェルグラフト共重合体」ともいう。）について述べる。 本発明に用いられるコア/シェル構造を有するグラフト共重合体は、例えば、各種ゴム状重合体に１種または２種以上のビニル系単量体を、ラジカル重合技術によって一段であるいは多段で重合させることによって得ることができる。
ここでいうゴム状重合体の例としては、ポリブタジエン、スチレンーブタジエンブロック共重合ゴム、スチレンーブタジエンランダム共重合ゴム、アクリロニトリルーブタジエンブロック共重合ゴム、および上記ジエンゴムを水素添加または部分水素添加した飽和ゴム、イソプレンゴム、クロロプレンゴム、天然ゴム、シリコーンゴム、エチレンープロピレンージエンモノマー三元共重合体、アクリルゴムおよびアクリル−シリコーン複合ゴム等が挙げられる。上記の各種ゴム成分は混合して用いても良いが、本発明においてはアクリル−シリコーン複合ゴムが特に好ましい。
【００５２】
前記ゴム状重合体を形成させるには乳化重合による方法が好ましい。また上記ゴム状重合体は、架橋性単量体を用いることも出来る。架橋性単量体としては例えば、ジビニルベンゼン等の芳香族ジビニル化合物、エチレングリコールジアクリレート、エチレングリコールジメタクリレート等のアルカンポリオールポリアクリレートまたはアルカンポリオールポリメタクリレート、アリルメタクリレート等のアリル化合物を挙げることが出来る。
【００５３】
前述のアクリル−シリコーン複合ゴムとは、ポリオルガノシロキサンゴム成分とポリアルキル（メタ）アクリレートゴム成分とが分離できないように相互に絡み合った構造を有している複合ゴムを意味する。更に詳細には、３員環以上の各種の環状オルガノシロキサン、例えばヘキサメチルシクロトリシロキサン、オクタメチルシクロテトラシロキサン、デカメチルシクロペンタシロキサン等と、架橋剤及び／又はグラフト交叉剤を用いて乳化重合によりポリオルガノシロキサンゴムのラテックスを調整し、次にアルキル（メタ）アクリレート単量体、架橋剤及びグラフト交叉剤とをポリオルガノシロキサンゴムのラテックスに含浸させてから重合させてなる複合ゴムである。ここで用いられるアルキル（メタ）アクリレート単量体としては、メチルアクリレート、エチルアクリレート、ｎ−プロピルアクリレート、ｎ−ブチルアクリレート、２−エチルヘキシルアクリレート等のアルキルアクリレート及びヘキシルメタクリレート、２−エチルヘキシルメタクリレート等のアルキルメタクリレートが挙げられるが、特にｎ−ブチルアクリレートを用いることが好ましい。
【００５４】
また、複合化に際しては、ポリオルガノシロキサンゴム成分が９０重量％を超えるとこの複合ゴムを用いたグラフト共重合体を樹脂に添加して得られる組成物の表面外観が悪化し、逆にポリアルキル（メタ）アクリレートゴム成分が９０重量％を超えると得られるグラフト共重合体の耐摩耗性、耐衝撃性向上効果が低下する。このため、本発明で用いる複合ゴムとしては複合を構成する２種のゴム成分はいずれも１０〜９０重量％（両ゴム成分の合計量１００重量％）の範囲にあることが必要であり、２０〜８０重量％の範囲にあることが好ましい。
【００５５】
上記複合ゴムの平均粒子径は０．０１〜１．０μｍ好ましくは０．０８〜０．６μｍである。平均粒子径が０．０１μｍ未満になると得られるグラフト共重合体の耐摩耗性、耐衝撃性向上効果が低下し、１．０μｍより大きくなるとグラフト共重合体の耐摩耗性、耐衝撃性向上効果が低下すると共にグラフト共重合体を樹脂に添加して得られる組成物の表面外観が悪化する。 なお本アクリル−シリコーン複合ゴムの製造に関しては特公平８−３０１０２号公報（三菱レイヨン株式会社）に詳細に記載されている。
【００５６】
上記のようにして得られた各種ゴム状重合体に１種または２種以上のビニル系単量体を、ラジカル重合技術によって一段であるいは多段で重合させることにより、本発明に用いられるコア/シェル構造を有するグラフト共重合体が得られる。又、製造の際に副生するグラフト成分のみのコポリマーとの混合物であってもよい。
【００５７】
かかる各種ゴム状重合体にグラフト重合させるビニル系単量体としては、スチレン、α−メチルスチレン、メチル（o-,m-,p-）スチレン、エチルスチレン、イソブチルスチレン、tert-ブチルスチレン、ブロムスチレン、ビニルナフタレン等の芳香族ビニル化合物、アクリロニトリル、メタクリロニトリル等のシアン化ビニル化合物、メチルメタクリレート、２−エチルヘキシルメタクリレート、エチルメタクリレート、プロピルメタクリレート、ヒドロキシエチルメタクリレート、シクロヘキシルメタクリレート、ブチルメタクリレート等のアルキルメタクリル酸エステル、メチルアクリレート、エチルアクリレート、ブチルアクリレート等のアクリル酸エステル等が挙げられ、これらは単独もしくは２種以上組み合わせて用いられる。
【００５８】
ゴム状重合体として前述のアクリル−シリコーン複合ゴムを用い、１種または２種以上のビニル系単量体を、ラジカル重合技術によって一段であるいは多段で重合させることにより得られる複合ゴム系コア/シェル共重合体を使用する場合に、より良好な耐摩耗性、耐衝撃性が得られ、好ましく使用できるものである。この複合ゴム系コア/シェル共重合体は前記と同様の方法で製造されるがより詳細には特公平８−３０１０２号公報（三菱レイヨン株式会社）に記載される方法で製造される。
【００５９】
ゴム状重合体（コア層）とビニル系単量体（シェル層）の重量比は、このコア/シェルグラフト共重合体全体を１００重量部として、コア層が３０〜９５重量部、シェル層が５〜７０重量部であることが好ましく、コア層が４０〜９０重量部、シェル層が１０〜６０重量部であることがより好ましい。シェル層が５重量部未満では樹脂中でのコア/シェルグラフト共重合体の分散が十分でなく、また７０重量部を越えると衝撃強度の発現性が不十分となり好ましくない。
【００６０】
こうして得られるコア/シェルグラフト共重合体として好ましい平均粒子径は０．０５〜５μｍである。０．０５μｍ未満では、耐衝撃性と耐摩耗性の改良が不十分であり、５μｍを超える粒子径であると成形表面外観を損なうと共に耐衝撃性と耐摩耗性の改良が不十分である。
【００６１】
また本発明に用いられるコア/シェルグラフト共重合体において、重合時に用いる乳化剤、凝集剤等不純物の残留は電気特性を問題とする像形成部材とりわけ電子写真用感光体においてはその電気特性を損なう恐れがあるため、必要に応じて精製して用いることが好ましい。精製法としては酸、アルカリ水溶液、水およびアルコールなどで攪拌洗浄処理する方法またソックスレー抽出等による固液抽出法が挙げられる。
【００６２】
かかるコア/シェル構造を有するグラフト共重合体の像形成部材における使用量は、用いるマトリックス樹脂により表面外観、耐衝撃性および耐摩耗性等を考慮し任意に選択できるが、電子写真用感光体として用いる場合は感光層中における割合として２０重量％以下、より好ましくは１０重量％以下である。２０重量％以上使用すると、感光体の表面平滑性の低下、残留電位上昇等の副作用をもたらす。
【００６３】
また、コア/シェル構造を有するグラフト共重合体を樹脂に添加する方法としては、汎用の溶媒中で攪拌する方法、ボールミリング法、振動ミリング法及び超音波法などの手段を用いることができる。または、バンバリーミキサー、ロールミル、２軸押出し機などの公知の装置を用い機械的に混合しペレット状に賦形する方法を挙げることができる。押し出し賦形されたペレットは、幅広い温度範囲で成型可能であり、成型には通常の射出成型機が用いられる。ペレット状に賦形されたコア/シェル構造を有するグラフト共重合体と樹脂は、更に上記の溶液分散法へ適用できる。
【００６４】
以下に本発明で使用されるコア/シェル構造を有するグラフト共重合体の代表的な例を示す。 例えば鐘淵化学工業（株）のカネエースＢシリーズ、三菱レイヨン（株）のメタブレンＣシリーズ、メタブレンＳシリーズ、メタブレンＷシリーズ、呉羽化学工業（株）のパラロイドＥＸＬシリーズ、ＨＩＡシリーズ、ＢＴＡシリーズ、ＫＣＡシリーズ、日本ゼオン（株）のハイブレンＢ６２１、武田薬品（株）のスタフロイド、ゼネラルエレクトリック（株）のＢＬＥＮＤＥＸ９８０、ロームアンドハース（株）のＫＭ３３４、ＫＭ３３０、エルファトケム（株）のＤＵＲＡＳＴＲＥＮＧＴＨ ２００、ＭＥＴＡＢＬＥＮＤ Ｓ−２００１、カネカテキサスコーポレーション（株）のＦＭ１０、ＦＭ２０等という商品名で市販されているものが挙げられるが、これらのものに限定されるものではない。またこれらコア/シェル構造を有するグラフト共重合体の中で、ゴム状重合体（コア層）が複合化されている三菱レイヨン（株）のメタブレンＳシリーズが特に好ましい。なお、特開平１０−１８２８４１号公報に記載されたコロイダルシリカをコアとし、ポリオルガノシロキサンをシェルとするコアシェル体及びビニルモノマーをグラフト共重合した共重合体、特開平５−２０９０２７号公報に記載された有機溶媒又は水に分散性を有するコロイダルシリカ表面をアルコキシシラン化合物で処理した後、分散媒をラジカル重合性ビニル化合物で置換しそれを重合することによって得られるコア/シェル構造を有するグラフト共重合体も用いることができる。
【００６５】
以上本発明の電子写真用感光体に使用されるコア/シェル構造を有するグラフト共重合体について説明してきたが、このものを電子写真用感光体に含有させる実施形態について以下に説明する。
【００６６】
本発明の感光体の断面図を図１〜図７に示す。 本発明の感光体はコア/シェルグラフト共重合体を感光層２、２’、２”、２”’、２””、２””’、2”””に含有させたものであるが、これらの応用の仕方によって図１、図２、図３、図４、図５、図６あるいは図７に示したように用いることができる。
【００６７】
図１における感光体は導電性支持体１上に電荷発生物質５とコア/シェルグラフト共重合体３を電荷輸送能を有する樹脂単独あるいは該樹脂と結合剤とを併用してなる電荷輸送媒体４の中に分散せしめた感光層２が設けられたものである。ここでの電荷輸送能を有する樹脂は単独であるいは結合剤との併用で電荷輸送媒体を形成し、一方、電荷発生物質５（無機又は有機顔料のような電荷発生物質）が電荷担体を発生する。この場合、電荷輸送媒体４は主として電荷発生物質５が発生する電荷担体を受入れ、これを輸送する作用を担当している。そしてこの感光体にあっては電荷発生物質と電荷輸送能を有する樹脂とが、互いに主として可視領域において吸収波長領域が重ならないというのが基本的条件である。これは電荷発生物質５に電荷担体を効率よく発生させるためには、電荷発生物質表面まで光を透過させる必要があるからである。なお、上記電荷輸送媒体４中に低分子電荷輸送物質を含有させてもよいし、低分子電荷輸送物質と結合剤からなる電荷輸送媒体を使用してもよい。
【００６８】
図２における感光体は電荷輸送層４上に保護層６を設けたものである。本構成の場合は電荷輸送層４上に電荷輸送能を有する樹脂あるいは該樹脂と結合剤とを併用し、その中にコア/シェルグラフト共重合体３を加えて保護層６が形成される。低分子電荷輸送物質と結合剤及びコア/シェルグラフト共重合体からなる保護層も使用できる。なお電荷輸送物質を含まない即ち結合剤とコア/シェルグラフト共重合体による保護層も形成できる。
【００６９】
図３における感光体は導電性支持体１上に電荷発生物質５を主体とする電荷発生層７と、電荷輸送能を有する樹脂とコア/シェルグラフト共重合体３を含有する電荷輸送層４との積層からなる感光層２”が設けられたものである。この感光体では電荷輸送層４を透過した光が電荷発生層７に到達し、その領域で電荷担体の発生が起こり、一方電荷輸送層４は電荷担体の注入を受け、その輸送を行うもので、光減衰に必要な電荷担体の発生は電荷発生物質５で行われ、また電荷担体の輸送は電荷輸送層４で行われる。こうした機構は図１に示した感光体においてした説明と同様である。なお電荷輸送媒体４は電荷輸送能を有する樹脂単独あるいはこれと結合剤との併用で形成される。また電荷発生効率を高めるために、電荷発生層７に電荷輸送能を有する樹脂あるいは低分子電荷輸送物質を含有させてもよい。同様の目的で感光層２”中に低分子電荷輸送物質と併用してもよい。又、低分子電荷輸送物質と結合剤からなる電荷輸送層媒体も使える。後述の感光層２”’〜2”””についても同様である。
【００７０】
図４における感光体は、コア/シェルグラフト共重合体を含まない電荷輸送層４上に図２と同様な方法で保護層６を設けたものである。なお電荷輸送層にコア/シェルグラフト共重合体を含有させても良い。
【００７１】
図５における感光体はコア/シェルグラフト共重合体を含有する図３の電荷発生層７と、電荷輸送能を有する樹脂或いは低分子電荷輸送物質と結合剤による組成物を含有する電荷輸送層４の積層順を逆にした感光体である。
【００７２】
図６における感光体は、コア/シェル構造を有するグラフト共重合体を含まない電荷発生層７上に図２と同様な方法で保護層６を設けたものである。なお電荷発生層７にコア/シェルグラフト共重合体を含有させても良い。
【００７３】
図７における感光体は導電性支持体１上にコア/シェル構造を有するグラフト共重合体、増感染料及び電荷輸送能を有する樹脂単独あるいは結合剤との併用または低分子電荷輸送物質と結合剤で形成される感光層2”””が設けられたものである。ここでの電荷輸送能を有する樹脂または低分子電荷輸送物質は光導電性物質として作用し、光減衰に必要な電荷担体の生成及び移動は電荷輸送能を有する樹脂または低分子電荷輸送物質を介して行われる。しかしながら、電荷輸送能を有する樹脂または低分子電荷輸送物質は光の可視領域においてほとんど吸収を有していないので、可視光で画像を形成する目的のためには、可視領域に吸収を有する増感染料を添加して増感する必要がある。
【００７４】
図１に示した感光体を作製するには、１種又は２種以上の電荷輸送能を有する樹脂あるいは結合剤を併用し溶解した溶液にコア/シェルグラフト共重合体３と電荷発生物質５の微粒子を分散せしめ、これを導電性支持体１上に塗布し乾燥して感光層２を形成すればよい。感光層の厚さは３〜５０μｍ、好ましくは５〜４０μｍが適当である。感光層２に占める結合剤の量は３０〜９５重量％である。その中コア/シェルグラフト共重合体の含有量は、感光層２における固形分に対し２０重量％以下であり、好ましくは１０重量％以下である。また電荷輸送能を有する樹脂の代わりに、低分子電荷輸送物質と結合剤による組成物も適用できる。
【００７５】
又、感光層２に占める電荷発生物質３の量は０．１〜５０重量％、好ましくは１〜２０重量％である。電荷発生物質３として、一般式（１）、（９）、（１２）で表わされるアゾ化合物の製造方法及び具体的な化合物例などは、それぞれ特開昭５３−１３２３４７号公報、特開昭５４−２２８３４号公報、特願平２−２４８７０８号、特開昭５３−１３３４４５号公報に記載されている。
【００７６】
また一般式（１４）に表されるフタロシアニン顔料の詳細を説明する。 式中Ｍは金属を表すか、金属が存在しない無金属フタロシアニンの場合には二つの水素原子を表す。
【００７７】
【化４１】

【００７８】
ここであげられるＭ（中心金属）は、Ｈ、Ｌｉ、Ｂｅ、Ｎａ、Ｍｇ、Ａｌ、Ｓｉ、Ｋ、Ｃａ、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｇａ、Ｇｅ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ｔｃ、Ｒｕ、Ｒｈ、Ｐｄ、Ａｇ、Ｃｄ、Ｉｎ、Ｓｎ、Ｓｂ、Ｂａ、Ｈｆ、Ｔａ、Ｗ、Ｒｅ、Ｏｓ、Ｉｒ、Ｐｔ、Ａｕ、Ｈｇ、Ｔｌ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、Ｔｈ、Ｐａ、Ｕ、Ｎｐ、Ａｍ等の単体、もしく酸化物、塩化物、フッ化物、水酸化物、臭化物などの２種以上の元素からなる。中心金属は、これらの元素に限定されるものではない。本発明におけるフタロシアニン骨格を有する電荷発生物質とは、少なくとも一般式（１４）の基本骨格を有していればよく、２量体、３量体など多量体構造を持つもの、さらに高次の高分子構造を持つものでもかまわない。また基本骨格に様々な置換基があるものでもかまわない。
【００７９】
これらの様々なフタロシアニンのうち、中心金属にＴｉＯを有するオキソチタニウムフタロシアニン、Ｈを有する無金属フタロシアニンは、感光体特性的に、特に好ましい。
【００８０】
またこれらのフタロシアニンは、様々な結晶系を持つことも知られており、例えばオキソチタニウムフタロシアニンの場合、α、β、γ、ｍ、ｙ型等、銅フタロシアニンの場合、α、β、γ等の結晶多系を有している。同じ中心金属を持つフタロシアニンにおいても、結晶系が変わることにより、種々の特性も変化する。その中で、感光体特性も、このような結晶系変化に伴い、変化することが報告されている。（電子写真学会誌 第２９巻 第４号(1990)）、このことから、各フタロシアニンは、感光体特性的に、最適な結晶系が存在し、特にオキソチタニウムフタロシアニンにおいては、ｙ型の結晶系が望ましい。
【００８１】
又は、上記の一般式(1),(9),(12)及び(14)の他にセレン、セレン−テルル、硫化カドミウム、硫化カドミウム−セレン、α−シリコンなどの無機材料、有機材料としては例えばシーアイピグメントブルー２５（カラーインデックスＣＩ２１１８０）、シーアイピグメントレッド４１（ＣＩ２１２００）、シーアイアシッドレッド５２（ＣＩ４５１００）、シーアイベーシックレッド３（ＣＩ４５２１０）、カルバゾール骨格を有するアゾ顔料（特開昭５３−９５０３３号公報に記載）、ジベンゾチオフェン骨格を有するアゾ顔料（特開昭５４−２１７２８号公報に記載）、オキサジアゾール骨格を有するアゾ顔料（特開昭５４−１２７４２号公報に記載）、ビススチルベン骨格を有するアゾ顔料（特開昭５４−１７７３３号公報に記載）、ジスチリルオキサジアゾール骨格を有するアゾ顔料（特開昭５４−２１２９号公報に記載）、ジスチリルカルバゾール骨格を有するアゾ顔料（特開昭５４−１４９６７号公報に記載）などのアゾ顔料、例えばシーアイバットブラウン５（ＣＩ７３４１０）、シーアイバットダイ（ＣＩ７３０３０）などのインジゴ系顔料、アルゴスカーレットＢ（バイエル社製）、インダンスレンスカーレットＲ（バイエル社製）などのペリレン系顔料などの顔料も同様に使用できる。また上記記載の電荷発生物質は２種以上混合してもかまわない。
【００８２】
図２に示した感光体を作製するには、１種又は２種以上の電荷輸送能を有する樹脂あるいはこれと結合剤を併用し溶解した溶液または低分子電荷輸送物質を結合剤とともに溶解した溶液に電荷発生物質５の微粒子を分散せしめ、これを導電性支持体１上に塗布し乾燥して感光層２’を形成する。この感光層上に電荷輸送能を有する樹脂を単独であるいは結合剤と併用してまたは低分子電荷輸送物質を結合剤とともににコア/シェルグラフト共重合体と溶解、分散し塗布し、乾燥して、保護層６が設けられる。保護層の厚さは０．１５〜１０μｍが好ましい。保護層６中に占める樹脂の量は４０〜９５重量％であり、コア/シェルグラフト共重合体の量は、樹脂に対して、２０重量％以下であり、好ましくは１０重量％以下である。結合剤とコア/シェルグラフト共重合体からなる保護層も使える。
【００８３】
図３に示した感光体を作製するには、導電性支持体１に電荷発生物質を真空蒸着するか、あるいは電荷発生物質の微粒子５を必要によって結合剤を溶解した適当な溶媒中に分散した分散液を塗布し乾燥して、更に必要であればバフ研磨などの方法によって表面仕上げ、膜厚調整などを行って電荷発生層７を形成し、この上に１種又は２種以上の電荷輸送能を有する樹脂あるいはこれと結合剤と併用してまたは低分子電荷輸送物質を結合剤とともに、コア/シェルグラフト共重合体と溶解、分散した溶液を塗布し乾燥して電荷輸送層４を形成すればよい。
【００８４】
なおここで電荷発生層７の形成に用いられる電荷発生物質は、前記の感光層２の説明と同じものである。電荷発生層７の厚さは５μｍ以下、好ましくは２μｍ以下であり、電荷輸送層４の厚さは３〜５０μｍ、好ましくは５〜４０μｍが適当である。電荷発生層７が電荷発生層物質の微粒子５を結合剤中に分散させたタイプのものにあっては、電荷発生物質の微粒子５の電荷発生層７に占める割合は１０〜１００重量％、好ましくは５０〜１００重量％程度である。又、電荷輸送層４に占める電荷輸送能を有する樹脂の量は４０〜９５重量％であり、コア/シェルグラフト共重合体の量は、樹脂に対して、２０重量％以下であり、好ましくは１０重量％以下である。電荷輸送能を有する樹脂の代わりに低分子電荷輸送物質と結合剤からなる組成物を使用してもよいことは前記のとおりであるが、該電荷輸送物質として、一般式（１５）〜（１７）で表わされる化合物が用いられ、製造方法及び具体的な化合物例等はそれぞれ特公平２−２４８６４号公報、特公平４−６６０２３号公報、特開昭５３−２７０３３号公報に記載されている。
【００８５】
又は、一般式（１５）〜（１７）の化合物の他に下記のものも使用できる。 オキサゾール誘導体、オキサジアゾール誘導体（特開昭５２−１３９０６５号公報、同５２−１３９０６６号公報に記載）、イミダゾール誘導体、トリフェニルアミン誘導体（特開平３−２８５９６０号公報に記載）、ヒドラゾン誘導体（特開昭５５−１５４９５５号、同５５−１５６９５４号、同５５−５２０６３号、同５６−８１８５０号などの各公報に記載）、トリフェニルメタン誘導体（特公昭５1−１０９８３号公報に記載）、アントラセン誘導体（特開昭５１−９４８２９号公報に記載）、スチリル誘導体（特開昭５６−２９２４５号、同５８−１９８０４３号各公報に記載）、カルバゾール誘導体（特開昭５８−５８５５２号公報に記載）、ピレン誘導体（特開平２−９４８１２号公報に記載）など。
【００８６】
一般式（１８）で示した電荷輸送能を有する樹脂の製造方法及び具体的な化合物例は特開平９−２９７４１９号公報に記載されている。また、一般式（１８）の他に下記文献に記載された電荷輸送能を有する樹脂も使用できる。
【００８７】
特開昭５１−７３８８８号公報、特開昭５４−８５２７号公報、特開昭５４−１１７３７号公報、特開昭５６−１５０７４９号公報、特開昭５７−７８４０２号公報、特開昭６３−２８５５５２号公報、特開昭６４−１７２８号公報、特開昭６４−１３０６１号公報、特開昭６４−１９０４９号公報、特開平３−５０５５５号公報、特開平４−２２５０１４号公報、特開平４−２３０７６７号公報、特開平５−２３２７２７号公報、特開平５−３１０９０４号公報等、特開平８−２６９１８３号公報、特開平９−７１６４２号公報、特開平９−１０４７４６号公報に、特開平９−２７２７３５号公報、ＪＰ９８０６７０９、特開平９−２３５３６７号公報、特開平９−８７３７６号公報、特開平９−１１０９７６号公報、特開平９−２６８２２６号公報、ＪＰ９７０２４３４、特開平９−２２１５４４号公報、特開平９−２２７６６９号公報、特開平９−１５７３７８号公報、ＪＰ９７０２５８２、特開平９−３０２０８４号公報、特開平９−３０２０８５号公報、特開平９−３２８５３９号公報、特開平１１−５８３６号公報、特開平１１−７１４５３号公報、米国特許４，８０１，５１７号、同４，８０６，４４３号、同４，８０６，４４４号、同４，９３７，１６５号、同４，９５９，２８８号、同５，０３０，５３２号、同５，０３４，２９６号、同５，０８０，９８９号各明細書、特開昭６４−９９６４号公報、特開平３−２２１５２２号公報、特開平２−３０４４５６号公報、特開平４−１１６２７号公報、特開平４−１７５３３７号公報、特開平４−１８３７１号公報、特開平４−３１４０４号公報、特開平４−１３３０６５号各公報等。
【００８８】
図４に示した感光体を作成するには、導電性支持体１に電荷発生物質を真空蒸着するか、あるいは電荷発生物質の微粒子５を必要によって結合剤を溶解した適当な溶媒中に分散した分散液を塗布し乾燥して、更に必要であればバフ研磨などの方法によって表面仕上げ、膜厚調整などを行って電荷発生層７を形成し、この上に１種又は２種以上の電荷輸送能を有する樹脂単独あるいはこれと結合剤とを併用しまたは低分子電荷輸送物質を結合剤とともに溶解した溶液を塗布し乾燥して電荷輸送層４を形成した後図２に示した保護層６を設ければいい。
【００８９】
図５に示した感光体を作成するには、導電性支持体１上に電荷輸送能を有する樹脂の１種または２種以上あるいはこれと結合剤とを併用しまたは低分子電荷輸送物質を結合剤とともに溶解した溶液を塗布し、乾燥して電荷輸送層４を形成したのち、この電荷輸送層の上に電荷発生物質の微粒子をコア/シェルグラフト共重合体とともに必要によって結合剤を溶解した溶媒中に分散した分散液をスプレー塗工等の方法で塗布乾燥して電荷発生層７を形成すればよい。電荷発生層あるいは電荷輸送層の量比は図４で説明した内容と同様である。
【００９０】
図６に示した感光体を作成するには、導電性支持体１上に電荷輸送能を有する樹脂の１種または２種以上あるいはこれと結合剤とを併用しまたは低分子電荷輸送物質を結合剤とともに溶解した溶液を塗布し、乾燥して電荷輸送層４を形成したのち、この電荷輸送層の上に電荷発生物質の微粒子を必要によって結合剤を溶解した溶媒中に分散した分散液をスプレー塗工等の方法で塗布乾燥して電荷発生層７を形成した後、図２に示した保護層６を設ければいい。
【００９１】
図７に示した感光体を作成するには、導電性支持体１上にコア/シェルグラフト共重合体および電荷輸送能を有する樹脂の１種または２種以上あるいはこれと結合剤とを併用しまたは低分子電荷輸送物質を結合剤とともに溶解、分散し、更にこれに増感染料を加えた液をつくり、これを導電性支持体１上に塗布し乾燥して感光層2”””を形成すればよい。感光層の厚さは３〜５０μｍ、好ましくは５〜４０μｍが適当である。感光層2”””に占める電荷輸送能を有する樹脂または低分子電荷輸送物質の量は３０〜１００重量％であり、又、感光層2”””に占める増感染料の量は０．１〜５重量％、好ましくは０．５〜３重量％である。
【００９２】
増感染料としてはブリリアントグリーン、ビクトリアブルーＢ、メチルバイオレット、クリスタルバイオレット、アシッドバイオレット６Ｂのようなトリアリールメタン染料、ローダミンＢ、ローダミン６Ｇ、ローダミンＧエキストラ、エオシンＳ、エリトロシン、ローズベンガル、フルオレセインのようなキサンテン染料、メチレンブルーのようなチアジン染料、シアニンのようなシアニン染料が挙げられる。
【００９３】
なお、これらのいずれの感光体製造においても、導電性支持体１にはアルミニウムなどの金属板又は金属箔、アルミニウムなどの金属を蒸着したプラスチックフィルム、あるいは導電処理を施した紙などが用いられる。又、結合剤としてはポリアミド、ポリウレタン、ポリエステル、エポキシ樹脂、ポリケトン、ポリカーボネートなどの縮合樹脂や、ポリビニルケトン、ポリスチレン、ポリ−Ｎ−ビニルカルバゾール、ポリアクリルアミドのようなビニル重合体などが用いられるが、絶縁性で且つ接着性のある樹脂はすべて使用できる。
【００９４】
必要により可塑剤が結合剤に加えられるが、そうした可塑剤としてはハロゲン化パラフィン、ジメチルナフタリン、ジブチルフタレートが例示できる。また必要に応じて酸化防止剤、光安定剤、熱安定剤、滑剤などの添加剤を加えることができる。
【００９５】
更に以上のようにして得られる感光体には導電性支持体と感光層の間に、必要に応じて接着層又はバリヤ層を設けることができる。これらの層に用いられる材料としては、ポリアミド、ニトロセルロース、酸化アルミニウム、酸化チタンなどであり、また膜厚は１μｍ以下が好ましい。 本発明の感光体を用いて複写を行うには、感光面に帯電、露光を施した後、現像を行い必要によって紙などへ転写を行う。
【００９６】
このようにして得られたコア/シェルグラフト共重合体を含有する本発明の感光体は感度が高く、またコア層の低摩擦性および/または弾性機能に加えシェル層のマトリックス樹脂への相溶化機能によりきわめて耐久性に優れている。
【００９７】
次に図面を用いて本発明の電子写真方法ならびに電子写真装置を詳しく説明する。 第８図は、本発明の電子写真プロセスカートリッジおよび電子写真装置を説明するための概略図であり、下記するような変形例も本発明の範疇に属するものである。
【００９８】
第８図において、感光体１は本発明の感光体が用いられている。感光体１はドラム状の形状を示しているが、シート状、エンドレスベルト状のものであっても良い。帯電チャージャ３、転写前チャージャ７、転写チャージャ１０、分離チャージャ１１、クリーニング前チャージャ１３には、コロトロン、スコロトロン、固体帯電器（ソリッド・ステート・チャージャー）、帯電ローラを始めとする公知の手段が用いられる。
【００９９】
転写手段には、一般に上記の帯電器が使用できるが、図８に示されるように転写チャージャーと分離チャージャーを併用したものが効果的である。
【０１００】
画像露光部５と除電ランプ２等の光源には、蛍光灯、タングステンランプ、ハロゲンランプ、水銀灯、ナトリウム灯、発光ダイオード（ＬＥＤ）、半導体レーザー（ＬＤ）、エレクトロルミネッセンス（ＥＬ）などの発光物全般を用いることができる。そして、所望の波長域の光のみを照射するために、シャープカットフィルター、バンドパスフィルター、近赤外カットフィルター、ダイクロイックフィルター、干渉フィルター、色温度変換フィルターなどの各種フィルターを用いることもできる。かかる光源等は、第９図に示される工程の他に光照射を併用した転写工程、除電工程、クリーニング工程、あるいは前露光などの工程を設けることにより、感光体に光が照射される。
【０１０１】
現像ユニット６により感光体１上に現像されたトナーは、転写紙９に転写されるが、全部が転写されるわけではなく、感光体１上に残存するトナーも生ずる。このようなトナーは、ファーブラシ１４およびクリーニングブレード１５により、感光体より除去される。クリーニングは、クリーニングブラシだけで行なわれることもあり、クリーニングブラシにはファーブラシ、マグファーブラシを始めとする公知のものが用いられる。
【０１０２】
電子写真感光体に正(負)帯電を施し、画像露光を行うと、感光体表面上には正(負)の静電潜像が形成される。 これを負(正)極性のトナー（検電微粒子）で現像すれば、ポジ画像が得られるし、また正(負)極性のトナーで現像すれば、ネガ画像が得られる。 かかる現像手段には、公知の方法が適用されるし、また、除電手段にも公知の方法が用いられる。
【０１０３】
第９図には、本発明による電子写真プロセスの別の例を示す。感光体２１は本発明の感光体であり、駆動ローラ２２ａ，２２ｂにより駆動され、帯電チャージャ２３による帯電、像露光源２４による像露光、現像（図示せず）、転写チャージャ２５を用いる転写、光源２６によるクリーニング前露光、クリーニングブラシ２７によるクリーニング、除電光源２８による除電が繰返し行なわれる。第１０図においては、感光体２１(勿論この場合は支持体が透光性である)に支持体側よりクリーニング前露光の光照射が行なわれる。
【０１０４】
以上の図示した電子写真プロセスは、本発明における実施形態を例示するものであって、もちろん他の実施形態も可能である。例えば、第９図において支持体側よりクリーニング前露光を行っているが、これは感光層側から行ってもよいし、また、像露光、除電光の照射を支持体側から行ってもよい。 一方、光照射工程は、像露光、クリーニング前露光、除電露光が図示されているが、他に転写前露光、像露光のプレ露光、およびその他公知の光照射工程を設けて、感光体に光照射を行なうこともできる。
【０１０５】
以上に示すような画像形成手段は、複写装置、ファクシミリ、プリンター内に固定して組み込まれていてもよいが、プロセスカートリッジの形でそれら装置内に組み込まれてもよい。プロセスカートリッジとは、感光体を内蔵し、他に帯電手段、露光手段、現像手段、転写手段、クリーニング手段、除電手段を含んだ１つの装置（部品）である。プロセスカートリッジの形状等は多く挙げられるが、一般的な例として、第１０図に示すものが挙げられる。感光体１６は、本発明の感光体が用いられる。
【０１０６】
【実施例】
以下、実施例により本発明を説明する。
〈コア／シェル構造を有するグラフト共重合体の調製例〉
メタブレンＳＸ−００５（三菱レイヨン社製；オルガノポリシロキサンとアクリルの複合ゴムにアクリルをグラフト）６０．５ｇをイオン交換水５００ｍｌに採りHOMO MIXER(MARKII)を用い１５分間の攪拌操作を１２回行った。１２回目の洗浄水の電導度は１．７５μｓ/ｃｍだった。得られたメタブレンＳＸ−００５を凍結乾燥して５８．２ｇを得た。以降の実施例１〜９においては本操作で得られたメタブレンＳＸ−００５を使用する。
【０１０７】
〈実施例１〉
アルミ板上にメタノール／ブタノール混合溶媒に溶解したポリアミド樹脂（ＣＭ-8000：東レ社製）溶液をドクターブレードで塗布し、自然乾燥して０．３μmの中間層を設けた。この上に電荷発生物質として下記式（１０）で表されるビスアゾ化合物をシクロヘキサノンと2-ブタノンの混合溶媒中でボールミルにより粉砕し、得られた分散液をドクターブレードで塗布し、自然乾燥して０．５μmの電荷発生層を形成した。
【０１０８】
【化４２】

【０１０９】
次に、前記メタブレンＳＸ−００５ ０．０１２ｇと下記構造式（１９）の高分子電荷輸送物質（重量平均分子量＝１２８０００）２．３７５ｇをテトラヒドロフラン１５．９６ｍｌに採り、ボールミリングで３時間分散し、この分散液を前記電荷発生層上にドクターブレードで塗布し、自然乾燥し、次いで１２０℃で２０分間乾燥して厚さ２０μｍの電荷輸送層を形成して感光体を作製した。
【０１１０】
【化４３】

ｋ＝０．４２，ｊ＝０．５８ のランダム共重合体
【０１１１】
かくして作られた感光体について市販の静電複写紙試験装置［（株）川口電機製作所製ＳＰ４２８型］を用いて暗所で−６ＫＶのコロナ放電を２０秒間行って帯電せしめた後、感光体の表面電位Ｖ_m（Ｖ）を測定し、更に２０秒間暗所に放置した後、表面電位Ｖ₀（Ｖ）を測定した。次いで、タングステンランプ光を感光体表面での照度が５．３ ｌｕｘになるように照射して、Ｖ₀が１／２になるまでの時間（秒）を求め、露光量Ｅ_1/2（ｌｕｘ・ｓｅｃ）を算出した。その結果を、表２に示す。
【０１１２】
〈実施例２、３〉
実施例１におけるメタブレンＳＸ−００５と高分子電荷輸送物質の組成比（重量部）を表１のように代える他は実施例１と同様に感光体を作成し、電気特性の評価を行った。その結果を表１に示す。
【０１１３】
【表１】

【０１１４】
〈実施例４〉
アルミ板上に実施例１と同様に中間層と電荷発生層をそれぞれ形成して、その上に実施例１で用いた高分子電荷輸送物質２．５ｇをテトラヒドロフラン１５．９６ｍｌに溶解した溶液をドクターブレードで塗布し、自然乾燥し、１０μｍの高分子電荷輸送層を形成した。 次に、メタブレンＳＸ−００５と実施例１で用いた高分子電荷輸送物質の重量組成比が５：９５であるテトラヒドロフラン分散液を前記高分子電荷輸送層上にドクターブレードで塗布し、自然乾燥し、次いで１２０℃で２０分間乾燥して厚さ１０μｍの電荷輸送層を形成して感光体を製造した。実施例１と同様に電気特性の評価を行った。その結果を、表２に示す。
【０１１５】
〈実施例５〉
アルミ板上に実施例１と同様に中間層と電荷発生層をそれぞれ形成して、その上に下記組成の電荷輸送層塗工液をボールミリングで分散して、ドクターブレードで塗布し、自然乾燥し、２０μｍの分子分散型電荷輸送層を形成して感光体を作製した（部は重量部を表す）。
下記構造式（２０）の電荷輸送物質 ８．４部
ポリカーボネート樹脂 ９．３部
（パンライトTS2050、帝人化成社製）
メタブレンＳＸ−００５ ０．３６部
ジクロロメタン １００部
【０１１６】
【化４４】

【０１１７】
実施例１と同様に電気特性の評価を行った。その結果を、表２に示す。
【０１１８】
〈実施例６〉
電荷発生物質としてビスアゾ化合物を下記式（８）で表されるトリスアゾ化合物に代える他は実施例１と同様に感光体を作成し、電気特性の評価を行った。 その結果を、表２に示す。
【０１１９】
【化４５】

【０１２０】
〈実施例７〉
電荷発生物質としてビスアゾ化合物を下記式（２１）で表されるオキソチタニウムフタロシアニン顔料に代える他は実施例１と同様に感光体を作成し、電気特性の評価を行った。その結果を、表２に示す。
【０１２１】
【化４６】

【０１２２】
〈実施例８〉
電荷発生物質として実施例１に使われるビスアゾ化合物を下記式（１１）で表されるビスアゾ化合物に代える他は実施例１と同様に感光体を作成し、電気特性の評価を行った。その結果を表２に示す。
【０１２３】
【化４７】

【０１２４】
〈実施例９〉
電荷発生物質として使われるビスアゾ化合物を下記式（１３）で表されるビスアゾ化合物に代える他は実施例１と同様に感光体を作成し、電気特性の評価を行った。その結果を表２に示す。
【０１２５】
【化４８】

【０１２６】
また、以上の感光体を市販の電子写真複写機を用いて帯電せしめた後、原図を介して光照射を行って静電潜像を形成せしめ、乾式現像剤を用いて現像し、得られた画像（トナー画像）を普通紙上に静電転写し、定着したところ、鮮明な転写画像が得られた。現像剤として湿式現像剤を用いた場合も同様に鮮明な転写画像が得られた。
【０１２７】
摩耗量評価試験１ 実施例１で得られた感光体を試料としてテーバー摩耗試験を行った。工業規格JIS K 7204(1995)に従って、テーバー摩耗試験機（東洋精機社製）にてＣＳ−５摩耗輪を使用し、荷重１Ｋｇで３０００回転の摩耗試験を行い、３０００回転後の摩耗量を表２に示した。
【０１２８】
摩耗量評価試験２〜９ 摩耗量評価試験１で用いた感光体を実施例２〜９で得られた感光体に代える他は摩耗量評価試験１と同様にテーバー摩耗試験を行った。結果を表２に示した。
【０１２９】
〈比較例１〉
比較例としてグラフト共重合体（ＳＸ−００５）を用いない他は実施例１と同様にして感光体を作成し、テーバー摩耗試験を行った。結果を表２に示した。
【０１３０】
〈比較例２、３〉
実施例１におけるメタブレンＳＸ−００５をポリシロキサン微粒子（トレフィルＲ−９０２Ａ東レシリコン社製）（比較例２）または架橋型ポリスチレン微粒子（ＳＸ８７４２（Ｄ）−０５ 日本合成ゴム社製）（比較例３）にそれぞれ代える他は実施例１と同様に感光体を作成し、実施例７と同様にテーバー摩耗試験を行った。結果を表２に示す。
【０１３１】
〈比較例４〉
グラフト共重合体（ＳＸ−００５）を用いない他は実施例５と同様にして感光体を作成し、テーバー摩耗試験を行った。結果を表２に示した。
【０１３２】
【表２】

【０１３３】
表２に示した実施例１〜９の電子写真特性および摩耗量の評価結果から明らかなように、本発明による感光体はいずれも高い感度と優れた耐摩耗性を示すことがわかる。
【１３４】
また、上記の実施例においてはメタブレンＳＸ−００５を使用した例を示したが、同じくコア/シェル構造を有するグラフト共重合体であるメタブレンＳＰＫ２００（コア：シロキサン/アクリル、シェル：スチレン/アクリロニトリル）及びメタブレンＳＸ２（コア：シロキサン/アクリル、シェル：スチレン）を使用しても、上記と同様の効果が得られることを確認した。
【０１３５】
【発明の効果】
本発明の感光体は感光層中に少なくともコア/シェル構造を有するグラフト共重合体を有効成分として含有したものである。このグラフト共重合体はコア部分が低摩擦係数及び／又は弾性を有する共重合体であり、シェル部分が感光層のマトリックス樹脂との相溶性が良い重合体であることから、感光体の繰り返し使用時においてもコア部分の機能が持続することにより、高い耐久性を保つことができる。
【図面の簡単な説明】
【図１】本発明に係わる電子写真用感光体の層構成を示す断面図。
【図２】本発明に係わる電子写真用感光体の層構成を示す断面図。
【図３】本発明に係わる電子写真用感光体の層構成を示す断面図。
【図４】本発明に係わる電子写真用感光体の層構成を示す断面図。
【図５】本発明に係わる電子写真用感光体の層構成を示す断面図。
【図６】本発明に係わる電子写真用感光体の層構成を示す断面図。
【図７】本発明に係わる電子写真用感光体の層構成を示す断面図。
【図８】本発明の電子写真プロセスカートリッジおよび電子写真装置を説明するための概略図。
【図９】本発明による電子写真プロセスの他の例を示す概略図。
【図１０】本発明によるプロセスカートリッジの他の例を示す概略図。
【符号の説明】
（図１〜７について）
１ 導電性支持体
２、２’、２”、２”’、２””、２””’、2””” 感光層
３ コア／シェル構造を有するグラフト共重合体
４ 電荷輸送層又は電荷輸送媒体
５ 電荷発生物質
６ 保護層
７ 電荷発生層
（図８〜１０について）
１，１６、２１ 感光体
２ 除電ランプ
３，１７，２３ 帯電チャージャ
５，１９ 画像露光部
６ 現像ユニット
７、２５ 転写前チャージャ
８ レジストローラ
９ 転写紙
１０ 転写チャージャ
１１ 分離チャージャ
１２ 分離爪
１３ クリーニング前チャージャ
１４ ファーブラシ
１５ クリーニングブレード
１８、２７ クリーニングブラシ
２０ 現像ローラ
２２ａ 駆動ローラ
２２ｂ 駆動ローラ
２４ 像露光源
２６ クリーニング前露光
２８ 除電光源[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a highly sensitive and highly durable electrophotographic photosensitive member containing a graft copolymer having a core / shell structure in a photosensitive layer, and an electrophotographic apparatus and a process cartridge using the photosensitive member.
[0002]
[Prior art]
An electrophotographic method using an electrophotographic photosensitive member applied to a copying machine, a facsimile, a laser printer, a direct digital plate making machine, etc. means that at least an electrophotographic photosensitive member is subjected to charging, image exposure, and development processes, and then an image. This is a method comprising a process of transferring a toner image onto a holder (transfer paper), fixing, and cleaning the surface of the electrophotographic photosensitive member.
[0003]
Conventionally, as a photoconductor used in an electrophotographic system, a photoconductive layer mainly composed of selenium or a selenium alloy is provided on a conductive support, and inorganic photoconductive materials such as zinc oxide and cadmium sulfide are used. In general, those dispersed in a binder and those using an amorphous silicon-based material are known. However, in recent years, the cost is low, the degree of freedom in designing a photoconductor, and pollution-free. For example, organic photoreceptors are widely used.
[0004]
The organic electrophotographic photoreceptor includes a photoconductive resin typified by polyvinylcarbazole (PVK), a charge transfer complex type typified by PVK-TNF (2,4,7-trinitrofluorenone), Known are a pigment dispersion type typified by a phthalocyanine-binder, a function separation type photoreceptor using a combination of a charge generation material and a charge transport material, and the function separation type photoreceptor is attracting attention.
[0005]
The mechanism of electrostatic latent image formation in this function-separated type photoreceptor is that when the photoreceptor is charged and irradiated with light, the light passes through the transparent charge transport layer and is absorbed by the charge generation material in the charge generation layer, The charge-generating substance that has absorbed the light generates charge carriers, which are injected into the charge transport layer, move in the charge transport layer according to the electric field generated by the charge, and neutralize the charge on the surface of the photoreceptor. Thus, an electrostatic latent image is formed. In the function-separated type photoreceptor, it is known and useful to use a combination of a charge transport material having absorption mainly in the ultraviolet region and a charge generation material having absorption mainly in the visible region.
[0006]
However, many charge transport materials for organic electrophotographic photoreceptors used in electrophotographic methods have been developed as low-molecular compounds, and low-molecular compounds do not have film-forming properties by themselves. Used by dispersing and mixing. However, a charge transport layer composed of a low-molecular charge transport material and an inert polymer is generally soft, and when repeatedly used in an electrophotographic process, the film may be scraped due to a mechanical load on the surface of the photoreceptor by a development system or a cleaning system. The disadvantage is low wear resistance, which is likely to occur.
[0007]
Further, the charge transport layer having this configuration has a limit in charge mobility, which has been an obstacle to speeding up or downsizing of the electrophotographic process. This is due to the fact that the content of the low molecular charge transport material is usually used at 50% by weight or less. That is, the charge mobility can be certainly increased by increasing the content of the low molecular charge transport material, but at the same time, the film formability and wear resistance are deteriorated.
[0008]
As a technique for improving the characteristics of the organic photoreceptor, an improved organic resin binder resin (JP-A-5-216250) or a charge transporting polymer (JP-A-51-73888, JP-A-54). -8527, JP 54-11737, JP 56-150749, JP 57-78402, JP 63-285552, JP 64-1728, JP 64-13061, JP 64-19049, JP 3-50555, JP 4-175337, JP 4-225014, JP 4-230767, JP-A-5-232727, JP-A-5-310904, etc.) have been noted and disclosed.
[0009]
In the above publication, it is difficult to improve the wear resistance of the improved charge transport layer binder resin due to the composition ratio of the low molecular charge transport material. On the other hand, the film using charge transport polymer can improve film scraping by polymerizing the charge transport layer component, but it is still sufficient to handle the photoconductor as a stationary part that does not replace the mechanical life. But further improvements are needed.
[0010]
On the other hand, in JP-A-07-295248, JP-A-07-301936, JP-A-08-082940, etc., the surface property is improved by incorporating fluorine-modified silicone oil in the surface layer, and the cleaning property is improved. There is a proposal to improve the wear resistance of the surface of the photoreceptor. However, when trying to contain fluorine-modified silicone oil in the surface layer, fluorine-modified silicone oil moves to the vicinity of the surface in the process of forming the surface layer and concentrates near the surface. The effect is lost early.
[0011]
Various attempts have also been made with respect to systems in which fine particles are added for the purpose of improving wear resistance. For example, silicone resin fine particles, fluorine-containing resin fine particles (Japanese Patent Laid-Open No. 63-65449), melamine resin fine particles (Japanese Patent Laid-Open No. 60-177349) and the like are added. Japanese Laid-Open Patent Publication No. 02-143257 proposes that the surface layer contains polyethylene powder to reduce the friction coefficient of the surface layer, thereby improving the cleaning property and improving the abrasion resistance of the photoreceptor. Japanese Laid-Open Patent Publication No. 02-144550 proposes that the surface layer contains a fluororesin powder to reduce the friction coefficient of the surface layer, thereby improving the cleaning property and improving the abrasion resistance of the photoreceptor. is there. In JP-A-07-128872 and JP-A-10-254160, the surface layer contains silicone fine particles to reduce the friction coefficient of the surface layer, thereby improving the cleaning property and improving the abrasion resistance of the photoreceptor. There are suggestions to improve. Japanese Patent Application Laid-Open No. 2000-010322 and US Pat. No. 5,998,072 contain cross-linked organic fine particles in the surface layer to reduce the friction coefficient of the surface layer, improve the cleaning property, and improve the wear resistance of the photoreceptor. There are suggestions to improve. Furthermore, Japanese Patent Application Laid-Open No. 08-190213 proposes that the surface layer contains methylsiloxane resin fine particles to reduce the friction coefficient of the surface layer, thereby improving the cleaning property and improving the abrasion resistance of the photoreceptor.
[0012]
These proposals are intended to increase durability by providing functions such as reduction of the coefficient of friction on the surface of the photoreceptor and reduction of surface energy, but have the following problems. That is, when resin powder or fine particles are dispersed in the surface layer to improve the abrasion resistance of the photosensitive layer surface, the resin powder or fine particles are not well dispersed due to poor compatibility with the binder resin. There is a problem that abnormal defects such as black spots and white spots occur during the formation, and the residual potential increases during repeated use. At the same time, since the light transmittance of the photosensitive layer is hindered, the problems such as the non-uniformity of image density due to the decrease in sensitivity and the decrease in charge transport performance have not been solved.
[0013]
[Problems to be solved by the invention]
The present invention has been made in view of the actual state of the above prior art, and includes a graft copolymer having a core / shell structure in an image forming member such as an electrophotographic photoreceptor, a transfer belt, and a fixing belt. An object is to provide a highly durable member. Another object is to provide a highly sensitive and durable electrophotographic photoreceptor.
[0014]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that the above problems can be solved by using an image forming member containing a graft copolymer having a core / shell structure as an active ingredient, and have reached the present invention.
[0015]
  That is, this invention is the following (1)-(14).
(1) A graft copolymer having an outermost layer having a core / shell structure in an electrophotographic photoreceptor comprising at least a charge generation material and a charge transport material on a conductive support.Particles ofAnd the charge generation material is a trisazo compound represented by the following general formula (1):The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
[0016]
Embedded image

(However, in the above general formula 1, R¹Represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a cyano group, and A represents a coupler residue. )
[0017]
(2) The coupler residue A in the trisazo compound of the general formula (1) is selected from the residues represented by the following general formulas (2) to (7). The electrophotographic photoreceptor as described.
[0018]
Embedded image

[0019]
[However, X in the above formula¹, Y¹And Z represent the following, respectively. X¹: —OH, —N (R²) (R^Three) Or -NHSO₂-R^Four. (R²And R^ThreeRepresents a hydrogen atom, an acyl group or a substituted or unsubstituted alkyl group, and R^FourRepresents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. ) Y¹: A hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxy group, a sulfone group, a benzimidazolyl group, a substituted or unsubstituted sulfamoyl group, a substituted or unsubstituted allophanoyl group, or -CON (R^Five) (Y²). {R^FiveRepresents a hydrogen atom, an alkyl group or a substituted product thereof, or a phenyl group or a substituted product thereof;²Is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or -N = C (R⁶) (R⁷) (However, R⁶Is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or a styryl group or a substituted product thereof, R⁷Represents a hydrogen atom, an alkyl group or a substituted product thereof, or a phenyl group or a substituted product thereof, or R6 and R7 may form a ring together with the carbon atom bonded thereto. } Z: A hydrocarbon ring group or a substituted product thereof, or a heterocyclic group or a substituted product thereof. ]
[0020]
Embedded image

(In the above formula, R⁸Represents a substituted or unsubstituted hydrocarbon group. )
[0021]
Embedded image

(In the above formula, R⁹Represents a substituted or unsubstituted hydrocarbon group. )
[0022]
Embedded image

(R in the above formula^TenRepresents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, and Ar¹Represents a substituted or unsubstituted aromatic hydrocarbon group. )
[0023]
Embedded image

(In the above formula, X²Represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group. )
[0024]
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(In the above formula, X²Represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group. )
[0025]
(3) The electrophotographic photoreceptor as described in (1) above, wherein the trisazo compound is a compound represented by the following formula (8).
[0026]
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[0027]
(4) An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support, wherein the outermost layer has a core / shell structure.Particles ofAnd the charge generation material is a bisazo compound represented by the following general formula (9):The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
[0028]
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(Wherein R¹¹And R¹²Represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group or a nitro group, which may be the same or different. B and C represent coupler residues and may be the same or different. Specifically, it is defined in the same manner as the coupler residue A shown in claim 2. )
[0029]
(5) The electrophotographic photoreceptor as described in (4) above, wherein the bisazo compound is a bisazo compound represented by the following formula (10):
[0030]
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[0031]
(6) The electrophotographic photoreceptor as described in (4) above, wherein the bisazo compound is a bisazo compound represented by the following formula (11):
[0032]
Embedded image

[0033]
(7) An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support, wherein the outermost layer has a core / shell structure.Particles ofAnd the charge generation material is a bisazo compound represented by the following general formula (12):The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
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(In the formula, D and E represent coupler residues and may be the same or different. Specifically, they are defined in the same manner as the coupler residue A shown in the above (2).)
[0034]
(8) The electrophotographic photoreceptor as described in (7) above, wherein the bisazo compound is a bisazo compound represented by the following formula (13):
Embedded image

[0035]
(9) An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support, wherein the outermost layer has a core / shell structure.Particles ofAnd the charge generation material is a phthalocyanine compound represented by the following general formula (14):The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
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[Wherein M represents a metal or, in the absence of a metal, two hydrogen atoms. ]
[0036]
(10) A graft copolymer having an outermost layer having a core / shell structure in an electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support.Particles ofAnd the charge generation material isunderA mixture of two or more compounds represented by the general formulas (1), (9), (12) and (14)The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
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(However, in the above general formula 1, R ¹ Represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a cyano group, and A represents a coupler residue. )
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(Wherein R ¹¹ And R ¹² Represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group or a nitro group, which may be the same or different. B and C represent coupler residues and may be the same or different. Specifically, it is defined in the same manner as the coupler residue A shown in claim 2. )
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(In the formula, D and E represent coupler residues and may be the same or different. Specifically, they are defined in the same manner as the coupler residue A shown in claim 2).
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[Wherein M represents a metal or, in the absence of a metal, two hydrogen atoms. ]
[0037]
(11) A graft copolymer in which the outermost layer has a core / shell structure in an electrophotographic photoreceptor comprising at least a charge generation material and a charge transport material on a conductive support.Particles ofAnd the charge transport material is an α-phenylstilbene derivative represented by the following general formula (15):The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
[0038]
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[0039]
(Where n is an integer of 0 or 1, Ar^FiveAnd Ar⁶Represents a substituted or unsubstituted aryl group (except for the case of an unsubstituted phenyl group at the same time), or a group that jointly forms a ring, Ar⁷Represents a substituted or unsubstituted aryl group, R¹⁶, R¹⁷And R¹⁸Represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and the aryl group and arylene group substituents include an alkoxy group, a phenoxy group, an alkyl group, a hydroxy group, a halogen atom, and a cyano group. Or a nitro group. )
[0040]
(12) The electrophotographic photoreceptor as described in (11) above, wherein the α-phenylstilbene derivative is an α-phenylstilbene derivative represented by the following general formula (16).
[0041]
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(Where R¹⁹Represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. )
[0042]
(13) An electrophotographic photoreceptor comprising at least a charge generation material and a charge transport material on a conductive support, wherein the outermost layer has a core / shell structure.Particles ofAnd the charge transport material is a benzidine compound represented by the following general formula (17):The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
[0043]
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(Wherein R²⁰Represents a lower alkyl group, a lower alkoxy group or a halogen atom, R^{twenty one}, R^{twenty two}May be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom, and h, l and m each represents an integer of 0 to 4. )
[0044]
(14) An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support, the outermost layer of which is a graft copolymer having a core / shell structureParticles ofAnd the charge transporting material is a charge transporting polymer having a triarylamine structure represented by the following general formula (18):The graft copolymer particles having the core / shell structure may be polymerized in one or more stages by radical polymerization technique with one or more vinyl monomers on the acrylic-silicone composite rubber-like polymer. It will beAn electrophotographic photoreceptor characterized by the above.
[0045]
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[0046]
[Wherein Ar¹, Ar², Ar^ThreeRepresents a substituted or unsubstituted arylene group. R¹, R²Represents the same or different acyl groups, substituted or unsubstituted alkyl groups, and substituted or unsubstituted aryl groups. k is an integer of 5 to 5000, j is an integer of 5 to 5000, and 0 <k / (k + j) ≦ 1. X is a substituted or unsubstituted aliphatic divalent group, a substituted or unsubstituted cyclic aliphatic divalent group, a substituted or unsubstituted aromatic divalent group, or a divalent group formed by linking these, or the following formula: Indicates what is represented. ]
[0047]
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[0048]
(Where R^Three, R^Four, R^Five, R⁶Are independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a halogen atom. A and b are each independently an integer of 0 to 4, c and d are each independently an integer of 0 to 3, and R^Three, R^Four, R^Five, R⁶May be the same or different when there are a plurality of each. Y represents a single bond, a linear alkylene group having 2 to 12 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 12 carbon atoms, one or more alkylene groups having 1 to 10 carbon atoms, and A divalent group composed of one or more oxygen and sulfur atoms, -O-, -S-, -SO-, -SO₂-, -CO-, -COO-, or
[0049]
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[0050]
Selected from Z¹, Z²Represents a substituted or unsubstituted aliphatic divalent group or a substituted or unsubstituted arylene group;⁷, R¹⁴Represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and R⁸, R⁹, R^Ten, R¹¹, R¹², R¹³Each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryl group. Also R⁸And R⁹May combine to form a carbocyclic ring having 5 to 12 carbon atoms.¹⁵And R¹⁶Represents a single bond or an alkylene group having 1 to 4 carbon atoms, and R¹⁷And R¹⁸Each independently represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, e and g are integers of 0 to 4, f is 1 or 2, h is an integer of 0 to 20, and i is 0 Represents an integer of ~ 2000. )
[0051]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the graft copolymer having a core / shell structure (hereinafter, also referred to as “core / shell graft copolymer”) used in the present invention will be described. The graft copolymer having a core / shell structure used in the present invention is obtained by, for example, polymerizing one or more vinyl monomers in various rubbery polymers in one step or in multiple steps by radical polymerization technology. Can be obtained.
Examples of the rubbery polymer mentioned here include polybutadiene, styrene-butadiene block copolymer rubber, styrene-butadiene random copolymer rubber, acrylonitrile-butadiene block copolymer rubber, and saturated hydrogenated or partially hydrogenated diene rubber. Examples thereof include rubber, isoprene rubber, chloroprene rubber, natural rubber, silicone rubber, ethylene-propylene-diene monomer terpolymer, acrylic rubber, and acrylic-silicone composite rubber. The above-mentioned various rubber components may be used as a mixture, but acrylic-silicone composite rubber is particularly preferred in the present invention.
[0052]
In order to form the rubber-like polymer, a method by emulsion polymerization is preferred. The rubbery polymer can also use a crosslinkable monomer. Examples of the crosslinkable monomer include aromatic divinyl compounds such as divinylbenzene, alkane polyol polyacrylates such as ethylene glycol diacrylate and ethylene glycol dimethacrylate, and allyl compounds such as alkane polyol polymethacrylate and allyl methacrylate. .
[0053]
The above-mentioned acrylic-silicone composite rubber means a composite rubber having a structure in which a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate rubber component are intertwined so that they cannot be separated. More specifically, emulsion polymerization using various cyclic organosiloxanes having three or more members, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and the like, and a crosslinking agent and / or a graft crossing agent. The composite rubber is prepared by preparing a latex of a polyorganosiloxane rubber by the following method, and then impregnating the latex of the polyorganosiloxane rubber with an alkyl (meth) acrylate monomer, a crosslinking agent and a graft crossing agent. Examples of the alkyl (meth) acrylate monomer used herein include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, and alkyls such as hexyl methacrylate and 2-ethylhexyl methacrylate. Although methacrylate is mentioned, it is particularly preferable to use n-butyl acrylate.
[0054]
In addition, in the case of compounding, if the polyorganosiloxane rubber component exceeds 90% by weight, the surface appearance of the composition obtained by adding the graft copolymer using this composite rubber to the resin is deteriorated, and conversely the polyalkyl When the (meth) acrylate rubber component exceeds 90% by weight, the effect of improving the wear resistance and impact resistance of the obtained graft copolymer is lowered. For this reason, as the composite rubber used in the present invention, both of the two rubber components constituting the composite must be in the range of 10 to 90% by weight (total amount of both rubber components is 100% by weight). It is preferably in the range of ˜80% by weight.
[0055]
The composite rubber has an average particle size of 0.01 to 1.0 μm, preferably 0.08 to 0.6 μm. When the average particle size is less than 0.01 μm, the effect of improving the wear resistance and impact resistance of the obtained graft copolymer is reduced. When the average particle size is larger than 1.0 μm, the effect of improving the wear resistance and impact resistance of the graft copolymer is decreased. And the surface appearance of the composition obtained by adding the graft copolymer to the resin deteriorates. The production of the acrylic-silicone composite rubber is described in detail in JP-B-8-30102 (Mitsubishi Rayon Co., Ltd.).
[0056]
The core / shell used in the present invention is obtained by polymerizing one or two or more vinyl monomers in a single stage or multiple stages by radical polymerization technique to various rubbery polymers obtained as described above. A graft copolymer having a structure is obtained. Moreover, the mixture with the copolymer of only the graft component byproduced in the case of manufacture may be sufficient.
[0057]
Examples of vinyl monomers to be graft-polymerized on such various rubbery polymers include styrene, α-methylstyrene, methyl (o-, m-, p-) styrene, ethyl styrene, isobutyl styrene, tert-butyl styrene, bromo. Aromatic vinyl compounds such as styrene and vinyl naphthalene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, alkyl methacrylate such as methyl methacrylate, 2-ethylhexyl methacrylate, ethyl methacrylate, propyl methacrylate, hydroxyethyl methacrylate, cyclohexyl methacrylate, and butyl methacrylate Examples thereof include acrylic acid esters such as acid ester, methyl acrylate, ethyl acrylate, and butyl acrylate, and these are used alone or in combination of two or more.
[0058]
A composite rubber core / shell obtained by polymerizing one or more vinyl monomers in one or more stages by radical polymerization technique using the above-mentioned acrylic-silicone composite rubber as a rubbery polymer. When a copolymer is used, better wear resistance and impact resistance can be obtained and can be preferably used. This composite rubber core / shell copolymer is produced by the same method as described above, but more specifically by the method described in Japanese Patent Publication No. 8-30102 (Mitsubishi Rayon Co., Ltd.).
[0059]
The weight ratio between the rubber-like polymer (core layer) and the vinyl monomer (shell layer) is 30 to 95 parts by weight for the core layer, 100 parts by weight for the entire core / shell graft copolymer, It is preferable that it is 5-70 weight part, It is more preferable that a core layer is 40-90 weight part and a shell layer is 10-60 weight part. If the shell layer is less than 5 parts by weight, the core / shell graft copolymer is not sufficiently dispersed in the resin, and if it exceeds 70 parts by weight, the expression of impact strength is insufficient, which is not preferable.
[0060]
A preferred average particle size of the core / shell graft copolymer thus obtained is 0.05 to 5 μm. If it is less than 0.05 μm, improvement in impact resistance and wear resistance is insufficient, and if the particle diameter exceeds 5 μm, appearance of the molding surface is impaired and improvement in impact resistance and wear resistance is insufficient.
[0061]
Further, in the core / shell graft copolymer used in the present invention, residual impurities such as emulsifiers and aggregating agents used in the polymerization may impair the electrical characteristics of an image forming member having an electrical property problem, particularly an electrophotographic photoreceptor. Therefore, it is preferable to use after purification if necessary. Examples of the purification method include a method of stirring and washing with an acid, an aqueous alkali solution, water and alcohol, and a solid-liquid extraction method such as Soxhlet extraction.
[0062]
The amount of the graft copolymer having such a core / shell structure used in the image forming member can be arbitrarily selected depending on the matrix resin used in consideration of the surface appearance, impact resistance, abrasion resistance, etc. When used, the proportion in the photosensitive layer is 20% by weight or less, more preferably 10% by weight or less. If it is used in an amount of 20% by weight or more, it causes side effects such as a decrease in surface smoothness of the photoreceptor and an increase in residual potential.
[0063]
In addition, as a method for adding the graft copolymer having a core / shell structure to the resin, means such as a method of stirring in a general-purpose solvent, a ball milling method, a vibration milling method, and an ultrasonic method can be used. Or the method of mechanically mixing using well-known apparatuses, such as a Banbury mixer, a roll mill, and a twin-screw extruder, and shape | molding in a pellet form can be mentioned. Extruded pellets can be molded over a wide temperature range, and a normal injection molding machine is used for molding. The graft copolymer and resin having a core / shell structure shaped into pellets can be further applied to the above solution dispersion method.
[0064]
Typical examples of the graft copolymer having a core / shell structure used in the present invention are shown below. For example, Kane Ace B series from Kaneka Chemical Co., Ltd., Metabrene C series, Metabrene S series, Metabrene W series from Mitsubishi Rayon Co., Ltd., Paraloid EXL series, HIA series, BTA series, KCA series from Kureha Chemical Industry Co., Ltd. HIBREN B621 from Nippon Zeon Co., Ltd., Staffroid from Takeda Pharmaceutical Co., Ltd., BLENDEX 980 from General Electric Co., Ltd., KM334, KM330 from Rohm and Haas Co., Ltd., DURASTRENGTH 200, METABLENEND S-2001 from Elfatochem Co. , Kaneka Texas Corporation's FM10, FM20, and the like, which are commercially available, are not limited to these. Among these graft copolymers having a core / shell structure, the Metablene S series of Mitsubishi Rayon Co., Ltd., in which a rubber-like polymer (core layer) is combined, is particularly preferable. A core-shell body having colloidal silica described in JP-A-10-182841 as a core and polyorganosiloxane as a shell, and a copolymer obtained by graft copolymerization with a vinyl monomer are described in JP-A-5-209027. A graft copolymer having a core / shell structure obtained by treating the surface of a colloidal silica dispersible in an organic solvent or water with an alkoxysilane compound and then replacing the dispersion medium with a radically polymerizable vinyl compound and polymerizing it. Coalescence can also be used.
[0065]
The graft copolymer having a core / shell structure used in the electrophotographic photoreceptor of the present invention has been described above. An embodiment in which this is contained in the electrophotographic photoreceptor will be described below.
[0066]
1 to 7 are sectional views of the photoreceptor of the present invention. The photoreceptor of the present invention comprises a core / shell graft copolymer contained in the photosensitive layer 2, 2 ', 2 ", 2"', 2 "", 2 "" ', 2 "" ". It can be used as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG.
[0067]
The photoreceptor in FIG. 1 is a charge transport medium 4 comprising a charge generating material 5 and a core / shell graft copolymer 3 on a conductive support 1, a resin having charge transport ability alone or a combination of the resin and a binder. The photosensitive layer 2 dispersed in is provided. The resin having charge transporting ability here forms a charge transporting medium alone or in combination with a binder, while the charge generating material 5 (charge generating material such as an inorganic or organic pigment) generates a charge carrier. . In this case, the charge transport medium 4 is mainly responsible for receiving and transporting charge carriers generated by the charge generating material 5. In this photoreceptor, the basic condition is that the charge generation substance and the resin having charge transporting ability do not overlap with each other mainly in the visible region. This is because in order to efficiently generate charge carriers in the charge generation material 5, it is necessary to transmit light to the surface of the charge generation material. The charge transport medium 4 may contain a low molecular charge transport material, or a charge transport medium composed of a low molecular charge transport material and a binder may be used.
[0068]
The photoreceptor in FIG. 2 has a protective layer 6 provided on the charge transport layer 4. In the case of this configuration, a protective layer 6 is formed by adding a resin having charge transporting capability or a resin and a binder in combination on the charge transporting layer 4 and adding the core / shell graft copolymer 3 therein. A protective layer comprising a low molecular charge transport material, a binder and a core / shell graft copolymer can also be used. It is also possible to form a protective layer containing no charge transport material, that is, a binder and a core / shell graft copolymer.
[0069]
3 includes a charge generation layer 7 mainly composed of a charge generation material 5 on a conductive support 1, a charge transport layer 4 containing a resin having a charge transport capability and a core / shell graft copolymer 3. In this photoreceptor, light that has passed through the charge transport layer 4 reaches the charge generation layer 7, where charge carriers are generated, while charge transport is performed. The layer 4 receives the injection of the charge carriers and transports them, and the charge carriers necessary for light attenuation are generated by the charge generating material 5 and the charge carriers are transported by the charge transport layer 4. The mechanism is the same as that described for the photoreceptor shown in Fig. 1. The charge transport medium 4 is formed by using a resin having a charge transport ability alone or in combination with a binder, and for increasing the charge generation efficiency. In addition, the charge generation layer 7 has a charge transport capability. A resin having low molecular weight or a low molecular charge transport material may be contained. For the same purpose, the photosensitive layer 2 ″ may be used in combination with a low molecular charge transport material. A charge transport layer medium comprising a low molecular charge transport material and a binder can also be used. The same applies to photosensitive layers 2 "'to 2" "" described later.
[0070]
The photoreceptor in FIG. 4 is obtained by providing a protective layer 6 on the charge transport layer 4 not containing the core / shell graft copolymer by the same method as in FIG. The charge transport layer may contain a core / shell graft copolymer.
[0071]
5 is a charge generation layer 7 of FIG. 3 containing a core / shell graft copolymer, and a charge transport layer 4 containing a resin or a low molecular charge transport material having a charge transport ability and a composition comprising a binder. The photoconductor is obtained by reversing the stacking order.
[0072]
The photoreceptor in FIG. 6 is obtained by providing the protective layer 6 on the charge generation layer 7 not including the graft copolymer having the core / shell structure by the same method as in FIG. The charge generation layer 7 may contain a core / shell graft copolymer.
[0073]
The photoreceptor in FIG. 7 is a graft copolymer having a core / shell structure on a conductive support 1, a sensitizing dye and a resin having a charge transporting ability alone or in combination with a binder, or a low molecular charge transporting substance and a binder. In this case, the resin or low molecular charge transport material having a charge transporting function acts as a photoconductive material, and is a charge carrier necessary for photoattenuation. Generation and transfer are carried out via a charge transporting resin or small molecule charge transport material, however, since the charge transporting resin or small molecule charge transport material has little absorption in the visible region of light. For the purpose of forming an image with visible light, it is necessary to add a sensitizing dye having absorption in the visible region for sensitization.
[0074]
In order to produce the photoreceptor shown in FIG. 1, the core / shell graft copolymer 3 and the charge generating material 5 are dissolved in a solution in which one or more resins or binders having a charge transporting ability are used in combination. The photosensitive layer 2 may be formed by dispersing the fine particles, applying the fine particles onto the conductive support 1 and drying it. The thickness of the photosensitive layer is 3 to 50 μm, preferably 5 to 40 μm. The amount of the binder in the photosensitive layer 2 is 30 to 95% by weight. Among them, the content of the core / shell graft copolymer is 20% by weight or less, preferably 10% by weight or less, based on the solid content in the photosensitive layer 2. Further, instead of a resin having a charge transporting ability, a composition comprising a low molecular charge transporting substance and a binder can be applied.
[0075]
The amount of the charge generating material 3 in the photosensitive layer 2 is 0.1 to 50% by weight, preferably 1 to 20% by weight. As the charge generation material 3, the production method of azo compounds represented by the general formulas (1), (9), and (12) and specific compound examples are disclosed in JP-A-53-132347 and JP-A-54. -22834, Japanese Patent Application No. 2-248708, and Japanese Patent Application Laid-Open No. 53-133445.
[0076]
Details of the phthalocyanine pigment represented by the general formula (14) will be described. In the formula, M represents a metal, or two hydrogen atoms in the case of a metal-free phthalocyanine in which no metal exists.
[0077]
Embedded image

[0078]
M (center metal) mentioned here is H, Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga , Ge, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl , La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Pa, U, Np, Am, etc., or oxide, chloride It consists of two or more elements such as fluoride, fluoride, hydroxide and bromide. The central metal is not limited to these elements. The charge generation material having a phthalocyanine skeleton in the present invention may have at least the basic skeleton of the general formula (14), and those having a multimeric structure such as a dimer and a trimer, It may have a molecular structure. Also, the basic skeleton may have various substituents.
[0079]
Of these various phthalocyanines, oxotitanium phthalocyanine having TiO as a central metal and metal-free phthalocyanine having H are particularly preferable in terms of photoreceptor characteristics.
[0080]
These phthalocyanines are also known to have various crystal systems, such as α, β, γ, m, y type in the case of oxotitanium phthalocyanine, α, β, γ, etc. in the case of copper phthalocyanine. It has a polycrystal system. Even in a phthalocyanine having the same central metal, various properties change as the crystal system changes. Among them, it has been reported that the photoconductor characteristics also change with such a crystal system change. (Journal of Electrophotographic Society, Vol. 29, No. 4 (1990)). From this, there is an optimum crystal system for each phthalocyanine in terms of the characteristics of the photoreceptor. In particular, in oxotitanium phthalocyanine, a y-type crystal system Is desirable.
[0081]
Or, in addition to the above general formulas (1), (9), (12) and (14), as inorganic materials and organic materials such as selenium, selenium-tellurium, cadmium sulfide, cadmium sulfide-selenium, α-silicon, etc. For example, CI Pigment Blue 25 (Color Index CI21180), CI Pigment Red 41 (CI21200), CI Acid Red 52 (CI45100), CI Basic Red 3 (CI45210), and an azo pigment having a carbazole skeleton (Japanese Patent Laid-Open No. 53-95033) An azo pigment having a dibenzothiophene skeleton (described in JP-A No. 54-21728), an azo pigment having an oxadiazole skeleton (described in JP-A No. 54-12742), and a bis-stilbene skeleton Azo pigment (described in JP-A-54-17733), distil An azo pigment such as an azo pigment having an oxadiazole skeleton (described in JP-A No. 54-2129) or an azo pigment having a distyrylcarbazole skeleton (described in JP-A No. 54-14967), for example, C.I. Indigo pigments such as CI 5410 (CI73410) and CI eyebat die (CI73030), and pigments such as perylene pigments such as Argo Scarlet B (manufactured by Bayer) and Indence Scarlet R (manufactured by Bayer) can also be used. Further, two or more kinds of the charge generating materials described above may be mixed.
[0082]
In order to produce the photoreceptor shown in FIG. 2, one or two or more kinds of resins having a charge transport ability, a solution in which this is combined with a binder, or a solution in which a low molecular charge transport material is dissolved together with a binder Then, the fine particles of the charge generating material 5 are dispersed on the conductive support 1 and dried to form a photosensitive layer 2 ′. On this photosensitive layer, a resin having a charge transport ability alone or in combination with a binder or a low molecular charge transport material together with a binder is dissolved, dispersed, applied, and dried. A protective layer 6 is provided. The thickness of the protective layer is preferably 0.15 to 10 μm. The amount of the resin in the protective layer 6 is 40 to 95% by weight, and the amount of the core / shell graft copolymer is 20% by weight or less, preferably 10% by weight or less based on the resin. A protective layer consisting of a binder and a core / shell graft copolymer can also be used.
[0083]
In order to produce the photoreceptor shown in FIG. 3, a charge generating material is vacuum-deposited on the conductive support 1, or fine particles 5 of the charge generating material are dispersed in a suitable solvent in which a binder is dissolved if necessary. The dispersion is applied and dried, and if necessary, the charge generation layer 7 is formed by surface finishing and film thickness adjustment by a method such as buffing, and one or more charge transports are formed thereon. The charge transport layer 4 is formed by applying a resin having a function or a combination thereof with a binder, or applying a low molecular charge transport material together with a binder and a solution dissolved and dispersed in a core / shell graft copolymer and drying. That's fine.
[0084]
Here, the charge generation material used for forming the charge generation layer 7 is the same as that of the photosensitive layer 2 described above. The thickness of the charge generation layer 7 is 5 μm or less, preferably 2 μm or less, and the thickness of the charge transport layer 4 is 3 to 50 μm, preferably 5 to 40 μm. When the charge generation layer 7 is of a type in which the charge generation layer material fine particles 5 are dispersed in a binder, the ratio of the charge generation material fine particles 5 to the charge generation layer 7 is 10 to 100% by weight, preferably Is about 50 to 100 wt%. The amount of the resin having charge transporting ability in the charge transport layer 4 is 40 to 95% by weight, and the amount of the core / shell graft copolymer is 20% by weight or less, preferably 10% by weight or less. As described above, a composition comprising a low-molecular charge transport material and a binder may be used in place of the resin having charge transport ability, and the general formulas (15) to (17) may be used as the charge transport material. The production method and specific compound examples are described in JP-B-2-24864, JP-B-4-66023 and JP-A-53-27033, respectively.
[0085]
Alternatively, the following compounds can be used in addition to the compounds of the general formulas (15) to (17). Oxazole derivatives, oxadiazole derivatives (described in JP-A-52-139065 and JP-A-52-139066), imidazole derivatives, triphenylamine derivatives (described in JP-A-3-285960), hydrazone derivatives (special No. 55-154955, No. 55-156955, No. 55-52063, No. 56-81850), Triphenylmethane derivatives (described in Japanese Patent Publication No. 51-10983), Anthracene derivatives (Described in JP-A No. 51-94829), styryl derivatives (described in JP-A Nos. 56-29245 and 58-198043), carbazole derivatives (described in JP-A No. 58-58552), Pyrene derivatives (described in JP-A-2-94812) and the like.
[0086]
A method for producing a resin having a charge transporting ability represented by the general formula (18) and specific compound examples are described in JP-A-9-297419. In addition to the general formula (18), resins having a charge transport ability described in the following documents can also be used.
[0087]
JP-A-51-73888, JP-A-54-8527, JP-A-54-11737, JP-A-56-15049, JP-A-57-78402, JP-A-63- No. 285552, JP-A 64-1728, JP-A 64-13061, JP-A 64-19049, JP-A 3-50555, JP-A 4-225014, JP-A 4 JP-A-9230767, JP-A-5-232727, JP-A-5-310904, JP-A-8-269183, JP-A-9-71642, JP-A-9-104746, JP-A-9-104746. JP-A-272735, JP9806709, JP-A-9-235367, JP-A-9-87376, JP-A-9-110976, JP-A-9-2682. No. 6, JP9702434, JP-A-9-221544, JP-A-9-227669, JP-A-9-157378, JP9702582, JP-A-9-302084, JP-A-9-302805, JP-A-9-20885 No. 9-328539, JP-A-11-5836, JP-A-11-71453, US Pat. Nos. 4,801,517, 4,806,443, 4,806,444, 4, No. 937,165, No. 4,959,288, No. 5,030,532, No. 5,034,296, No. 5,080,989, JP-A 64-9964, No. 3-221522, JP-A-2-304456, JP-A-4-11627, JP-A-4-175337, JP-A-4-18371 , JP-A 4-31404, JP-A No. 4-133065 Patent JP-like.
[0088]
In order to prepare the photoreceptor shown in FIG. 4, a charge generating material is vacuum-deposited on the conductive support 1, or fine particles 5 of the charge generating material are dispersed in a suitable solvent in which a binder is dissolved if necessary. The dispersion is applied and dried, and if necessary, the charge generation layer 7 is formed by surface finishing and film thickness adjustment by a method such as buffing, and one or more charge transports are formed thereon. After forming the charge transport layer 4 by applying and drying a resin having a function alone or in combination with a binder or a solution in which a low molecular charge transport material is dissolved together with the binder, the protective layer 6 shown in FIG. Just set up.
[0089]
In order to produce the photoreceptor shown in FIG. 5, one or more kinds of resins having charge transporting ability or a combination with a binder or a low molecular charge transporting substance are bound on the conductive support 1. After the solution dissolved with the agent is applied and dried to form the charge transport layer 4, a solvent in which the fine particles of the charge generating material are dissolved on the charge transport layer together with the core / shell graft copolymer and the binder as necessary is dissolved. The charge generation layer 7 may be formed by applying and drying the dispersion liquid dispersed therein by a method such as spray coating. The amount ratio of the charge generation layer or the charge transport layer is the same as that described in FIG.
[0090]
In order to prepare the photoreceptor shown in FIG. 6, one or more resins having charge transporting ability or a combination with a binder or a low molecular charge transporting substance are bonded on the conductive support 1. After the solution dissolved with the agent is applied and dried to form the charge transport layer 4, a dispersion in which fine particles of the charge generating material are dispersed in a solvent in which the binder is dissolved as necessary is sprayed on the charge transport layer. After forming the charge generation layer 7 by coating and drying by a method such as coating, the protective layer 6 shown in FIG. 2 may be provided.
[0091]
To prepare the photoreceptor shown in FIG. 7, one or more of a core / shell graft copolymer and a charge transporting resin or a binder and a binder are used on the conductive support 1. Alternatively, a low molecular charge transport material is dissolved and dispersed together with a binder, and then a solution in which a sensitizing dye is added to the solution is applied to the conductive support 1 and dried to form a photosensitive layer 2 "" ". The thickness of the photosensitive layer is 3 to 50 μm, preferably 5 to 40 μm. The amount of the resin having a charge transporting ability or the low molecular charge transporting material in the photosensitive layer 2 ″ ″ ″ is 30 to 100. The amount of the sensitizing dye in the photosensitive layer 2 "" "is 0.1 to 5% by weight, preferably 0.5 to 3% by weight.
[0092]
Examples of sensitizing dyes include triarylmethane dyes such as brilliant green, Victoria blue B, methyl violet, crystal violet, and acid violet 6B, rhodamine B, rhodamine 6G, rhodamine G extra, eosin S, erythrocin, rose bengal, and fluorescein. Xanthene dyes, thiazine dyes such as methylene blue, and cyanine dyes such as cyanine.
[0093]
In any of these photoreceptors, a metal plate or a metal foil such as aluminum, a plastic film vapor-deposited with a metal such as aluminum, or paper subjected to a conductive treatment is used for the conductive support 1. In addition, as binders, condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide are used. Any insulating and adhesive resin can be used.
[0094]
If necessary, a plasticizer is added to the binder. Examples of such a plasticizer include halogenated paraffin, dimethylnaphthalene, and dibutyl phthalate. If necessary, additives such as an antioxidant, a light stabilizer, a heat stabilizer, and a lubricant can be added.
[0095]
Further, the photoreceptor obtained as described above can be provided with an adhesive layer or a barrier layer between the conductive support and the photosensitive layer, if necessary. Materials used for these layers include polyamide, nitrocellulose, aluminum oxide, titanium oxide, and the like, and the film thickness is preferably 1 μm or less. In order to perform copying using the photoreceptor of the present invention, the photosensitive surface is charged and exposed, then developed, and transferred to paper or the like as necessary.
[0096]
The photoreceptor of the present invention containing the core / shell graft copolymer thus obtained has high sensitivity, and the shell layer is compatible with the matrix resin in addition to the low friction and / or elastic function of the core layer. Extremely durable by function.
[0097]
Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings. FIG. 8 is a schematic view for explaining the electrophotographic process cartridge and the electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
[0098]
In FIG. 8, the photoreceptor 1 of the present invention is used as the photoreceptor 1. The photosensitive member 1 has a drum shape, but may be a sheet shape or an endless belt shape. For the charging charger 3, the pre-transfer charger 7, the transfer charger 10, the separation charger 11, and the pre-cleaning charger 13, known means such as a corotron, a scorotron, a solid state charger, and a charging roller are used. It is done.
[0099]
As the transfer means, the above charger can be generally used. However, as shown in FIG. 8, a combination of a transfer charger and a separation charger is effective.
[0100]
Light sources such as the fluorescent lamp, tungsten lamp, halogen lamp, mercury lamp, sodium lamp, light emitting diode (LED), semiconductor laser (LD), electroluminescence (EL), etc. Can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. Such a light source or the like irradiates the photosensitive member with light by providing a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG.
[0101]
The toner developed on the photoreceptor 1 by the developing unit 6 is transferred to the transfer paper 9, but not all is transferred, and some toner remains on the photoreceptor 1. Such toner is removed from the photoreceptor by the fur brush 14 and the cleaning blade 15. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.
[0102]
When a positive (negative) charge is applied to the electrophotographic photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with toner of negative (positive) polarity (electrodetection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.
[0103]
FIG. 9 shows another example of the electrophotographic process according to the present invention. The photoconductor 21 is a photoconductor of the present invention, and is driven by driving rollers 22a and 22b. The photoconductor 21 is charged by a charging charger 23, image exposure by an image exposure source 24, development (not shown), transfer using a transfer charger 25, and light source. The pre-cleaning exposure by 26, the cleaning by the cleaning brush 27, and the static elimination by the static elimination light source 28 are repeated. In FIG. 10, the photoconductor 21 (of course, the support is translucent in this case) is irradiated with pre-cleaning exposure light from the support side.
[0104]
The above illustrated electrophotographic process is illustrative of an embodiment of the present invention, and of course other embodiments are possible. For example, in FIG. 9, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or image exposure and neutralization light irradiation may be performed from the support side. On the other hand, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and charge-removing exposure. Irradiation can also be performed.
[0105]
The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. There are many shapes and the like of the process cartridge, but a general example is the one shown in FIG. As the photoreceptor 16, the photoreceptor of the present invention is used.
[0106]
【Example】
Hereinafter, the present invention will be described by way of examples.
<Preparation example of graft copolymer having core / shell structure>
METABLEN SX-005 (manufactured by Mitsubishi Rayon Co., Ltd .; acrylic grafted on organopolysiloxane and acrylic composite rubber) 60.5 g was taken up in 500 ml of ion-exchanged water and stirred for 15 minutes using HOMO MIXER (MARKII) 12 times. . The conductivity of the 12th washing water was 1.75 μs / cm. The obtained Methbrene SX-005 was lyophilized to obtain 58.2 g. In the following Examples 1 to 9, metabrene SX-005 obtained by this operation is used.
[0107]
<Example 1>
A polyamide resin (CM-8000: manufactured by Toray Industries, Inc.) solution dissolved in a methanol / butanol mixed solvent was applied on an aluminum plate with a doctor blade, and air dried to provide a 0.3 μm intermediate layer. On this, a bisazo compound represented by the following formula (10) as a charge generating material is pulverized by a ball mill in a mixed solvent of cyclohexanone and 2-butanone, and the resulting dispersion is applied with a doctor blade and air-dried. A 0.5 μm charge generation layer was formed.
[0108]
Embedded image

[0109]
Next, 0.0175 g of the above-mentioned methabrene SX-005 and 2.375 g of a polymer charge transporting material (weight average molecular weight = 128000) of the following structural formula (19) are taken up in 15.96 ml of tetrahydrofuran and dispersed by ball milling for 3 hours. This dispersion was applied onto the charge generation layer with a doctor blade, naturally dried, and then dried at 120 ° C. for 20 minutes to form a charge transport layer having a thickness of 20 μm to produce a photoreceptor.
[0110]
Embedded image

Random copolymer with k = 0.42 and j = 0.58
[0111]
The photoreceptor thus prepared was charged by performing a -6 KV corona discharge for 20 seconds in the dark using a commercially available electrostatic copying paper testing apparatus [SP428 type manufactured by Kawaguchi Electric Co., Ltd.] Surface potential V_mAfter measuring (V) and leaving it in the dark for 20 seconds, the surface potential V₀(V) was measured. Next, the tungsten lamp light is irradiated so that the illuminance on the surface of the photosensitive member becomes 5.3 lux, and V₀Time (seconds) until ½ is obtained, and exposure amount E_1/2(Lux · sec) was calculated. The results are shown in Table 2.
[0112]
<Examples 2 and 3>
A photoconductor was prepared in the same manner as in Example 1 except that the composition ratio (parts by weight) of Methbrene SX-005 and the polymer charge transport material in Example 1 was changed as shown in Table 1, and the electrical characteristics were evaluated. The results are shown in Table 1.
[0113]
[Table 1]

[0114]
<Example 4>
An intermediate layer and a charge generation layer were formed on an aluminum plate in the same manner as in Example 1, and a solution obtained by dissolving 2.5 g of the polymer charge transport material used in Example 1 in 15.96 ml of tetrahydrofuran was added to the doctor. It apply | coated with the braid | blade and air-dried and formed the 10 micrometer polymeric charge transport layer. Next, a tetrahydrofuran dispersion having a weight composition ratio of 5:95 of the polymer charge transport material used in Example 1 and methabrene SX-005 was applied onto the polymer charge transport layer with a doctor blade and dried naturally. Subsequently, it was dried at 120 ° C. for 20 minutes to form a charge transport layer having a thickness of 10 μm to produce a photoreceptor. The electrical characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.
[0115]
<Example 5>
An intermediate layer and a charge generation layer are respectively formed on an aluminum plate in the same manner as in Example 1. A charge transport layer coating solution having the following composition is dispersed on the aluminum plate by ball milling, applied with a doctor blade, and naturally dried. Then, a 20 μm molecular dispersion type charge transport layer was formed to prepare a photoconductor (part represents part by weight).
8.4 parts of charge transport material of the following structural formula (20)
9.3 parts of polycarbonate resin
(Panlite TS2050, manufactured by Teijin Chemicals Ltd.)
Metabrene SX-005 0.36 parts
100 parts of dichloromethane
[0116]
Embedded image

[0117]
The electrical characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.
[0118]
<Example 6>
A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound was replaced with a trisazo compound represented by the following formula (8) as the charge generation material, and the electrical characteristics were evaluated. The results are shown in Table 2.
[0119]
Embedded image

[0120]
<Example 7>
A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound was replaced with an oxotitanium phthalocyanine pigment represented by the following formula (21) as a charge generation material, and the electrical characteristics were evaluated. The results are shown in Table 2.
[0121]
Embedded image

[0122]
<Example 8>
A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound used in Example 1 as a charge generation material was replaced with a bisazo compound represented by the following formula (11), and the electrical characteristics were evaluated. The results are shown in Table 2.
[0123]
Embedded image

[0124]
<Example 9>
A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound used as the charge generation material was replaced with a bisazo compound represented by the following formula (13), and the electrical characteristics were evaluated. The results are shown in Table 2.
[0125]
Embedded image

[0126]
Further, after charging the above photoreceptor using a commercially available electrophotographic copying machine, it was irradiated with light through an original drawing to form an electrostatic latent image, and developed using a dry developer. When the image (toner image) was electrostatically transferred and fixed on plain paper, a clear transferred image was obtained. Similarly, a clear transfer image was obtained when a wet developer was used as the developer.
[0127]
Wear amount evaluation test 1  A Taber abrasion test was conducted using the photoreceptor obtained in Example 1 as a sample. In accordance with the industrial standard JIS K 7204 (1995), using a CS-5 wear wheel with a Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.), a wear test of 3000 revolutions with a load of 1 kg is performed and the amount of wear after 3000 revolutions is shown. It was shown in 2.
[0128]
Wear amount evaluation test 2-9  The Taber abrasion test was conducted in the same manner as the abrasion amount evaluation test 1 except that the photoreceptor used in the abrasion amount evaluation test 1 was replaced with the photoreceptor obtained in Examples 2 to 9. The results are shown in Table 2.
[0129]
<Comparative example 1>
As a comparative example, a photoconductor was prepared in the same manner as in Example 1 except that the graft copolymer (SX-005) was not used, and a Taber abrasion test was performed. The results are shown in Table 2.
[0130]
<Comparative Examples 2 and 3>
Metabrene SX-005 in Example 1 was made of polysiloxane fine particles (Trefyl R-902A manufactured by Toray Silicon Co., Ltd.) (Comparative Example 2) or cross-linked polystyrene fine particles (SX8742 (D) -05 manufactured by Nippon Synthetic Rubber Co., Ltd.) (Comparative Example 3). A photoconductor was prepared in the same manner as in Example 1 except that each was replaced, and a Taber abrasion test was conducted in the same manner as in Example 7. The results are shown in Table 2.
[0131]
<Comparative example 4>
A photoconductor was prepared in the same manner as in Example 5 except that the graft copolymer (SX-005) was not used, and a Taber abrasion test was conducted. The results are shown in Table 2.
[0132]
[Table 2]

[0133]
As is apparent from the electrophotographic characteristics and wear amount evaluation results of Examples 1 to 9 shown in Table 2, it can be seen that all the photoreceptors according to the present invention exhibit high sensitivity and excellent wear resistance.
[134]
Further, in the above-mentioned examples, although examples using methabrene SX-005 were shown, methbrene SPK200 (core: siloxane / acryl, shell: styrene / acrylonitrile), which is also a graft copolymer having a core / shell structure, and It was confirmed that the same effect as described above was obtained even when Metablene SX2 (core: siloxane / acrylic, shell: styrene) was used.
[0135]
【The invention's effect】
The photoreceptor of the present invention contains at least a graft copolymer having a core / shell structure as an active ingredient in the photosensitive layer. This graft copolymer is a copolymer having a core portion having a low friction coefficient and / or elasticity, and a shell portion being a polymer having good compatibility with the matrix resin of the photosensitive layer. Even at times, high durability can be maintained by maintaining the function of the core portion.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 2 is a cross-sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 3 is a cross-sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 4 is a cross-sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 5 is a cross-sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 6 is a cross-sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 7 is a cross-sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 8 is a schematic view for explaining an electrophotographic process cartridge and an electrophotographic apparatus of the present invention.
FIG. 9 is a schematic view showing another example of the electrophotographic process according to the present invention.
FIG. 10 is a schematic view showing another example of a process cartridge according to the present invention.
[Explanation of symbols]
(About FIGS. 1-7)
1 Conductive support
2, 2 ', 2 ", 2"', 2 "", 2 "" ', 2 "" "photosensitive layer
3 Graft copolymer with core / shell structure
4 Charge transport layer or charge transport medium
5 Charge generation materials
6 Protective layer
7 Charge generation layer
(About FIGS. 8 to 10)
1,16,21 photoconductor
2 Static elimination lamp
3,17,23 Charger charger
5,19 Image exposure unit
6 Development unit
7, 25 Pre-transfer charger
8 Registration roller
9 Transfer paper
10 Transcription charger
11 Separate charger
12 Separating nails
13 Charger before cleaning
14 Fur brush
15 Cleaning blade
18, 27 Cleaning brush
20 Developing roller
22a Driving roller
22b Driving roller
24 Image exposure source
26 Exposure before cleaning
28 Static elimination light source

Claims (14)

An electrophotographic photoreceptor comprising at least a charge generation material and a charge transport material on a conductive support, the outermost layer containing particles of a graft copolymer having a core / shell structure, wherein the charge generation material is Ri trisazo compound der of the formula (1),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

(In the above general formula 1, R ¹ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a cyano group, and A represents a coupler residue.) The electrophotographic apparatus according to claim 1, wherein the coupler residue A in the trisazo compound of the general formula (1) is selected from the residues represented by the following general formulas (2) to (7). Photoconductor.

[However, in the above formula, X ¹ , Y ¹ and Z represent the following, respectively. ^{X 1: -OH, -N (R} 2) (R 3) or, -NHSO ₂ -R ^4. (R ² and R ³ represent a hydrogen atom, an acyl group, or a substituted or unsubstituted alkyl group, and R ⁴ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.) Y ¹ : Hydrogen atom , A halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxy group, a sulfone group, a benzimidazolyl group, a substituted or unsubstituted sulfamoyl group, a substituted or unsubstituted allophanoyl group, or —CON (R ⁵ ) (Y ² ). {R ⁵ represents a hydrogen atom, an alkyl group or a substituted product thereof, or a phenyl group or a substituted product thereof, Y ² represents a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or —N═C (R ⁶ ) (R ⁷ ) (wherein R ⁶ is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or a styryl group or a substituted product thereof, R ⁷ is a hydrogen atom, an alkyl group or a substituted product thereof, or phenyl Represents a group or a substituent thereof, or R6 and R7 may form a ring together with the carbon atom to which they are attached. } Z: A hydrocarbon ring group or a substituted product thereof, or a heterocyclic group or a substituted product thereof. ]

(In the above formula, R ⁸ represents a substituted or unsubstituted hydrocarbon group.)

(In the above formula, R ⁹ represents a substituted or unsubstituted hydrocarbon group.)

(In the above formula, R ¹⁰ represents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, and Ar ¹ represents a substituted or unsubstituted aromatic hydrocarbon group.)

(In the above formula, X ² represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group.)

(In the above formula, X ² represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group.) 2. The electrophotographic photoreceptor according to claim 1, wherein the trisazo compound is a compound represented by the following formula (8).

An electrophotographic photoreceptor comprising at least a charge generation material and a charge transport material on a conductive support, the outermost layer containing particles of a graft copolymer having a core / shell structure, wherein the charge generation material is Ri bisazo compounds der of the formula (9),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

(Wherein R ¹¹ and R ¹² represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group, or a nitro group, and may be the same or different. C represents a coupler residue and may be the same or different, and is specifically defined in the same manner as the coupler residue A shown in claim 2.) The electrophotographic photoreceptor according to claim 4, wherein the bisazo compound is a bisazo compound represented by the following formula (10):

The electrophotographic photoreceptor according to claim 4, wherein the bisazo compound is a bisazo compound represented by the following formula (11).

In an electrophotographic photoreceptor comprising at least a charge generating material and a charge transport material on a conductive support, the outermost layer contains particles of a graft copolymer having a core / shell structure. Ri bisazo compounds der of the formula (12),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

(In the formula, D and E are coupler residues and may be the same or different. Specifically, they are defined in the same manner as the coupler residue A shown in claim 2). The electrophotographic photoreceptor according to claim 7, wherein the bisazo compound is a bisazo compound represented by the following formula (13):

An electrophotographic photoreceptor comprising at least a charge generation material and a charge transport material on a conductive support, the outermost layer containing particles of a graft copolymer having a core / shell structure, wherein the charge generation material is Ri phthalocyanine compound der of the formula (14),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

[Wherein M represents a metal or, in the absence of a metal, two hydrogen atoms. ] In electrophotographic photoreceptor comprising at least a charge generating material and a charge-transporting material on the conductive support, containing the particles of the graft copolymer whose outermost layer has a core / shell structure, the upper under the charge generating material serial general formula (1), (9), it is two or more thereof der of the compounds represented by (12) and (14),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

(In the above general formula 1, R ¹ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a cyano group, and A represents a coupler residue.)

(Wherein R ¹¹ and R ¹² represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group or a nitro group, and may be the same or different. C represents a coupler residue and may be the same or different, and is specifically defined in the same manner as the coupler residue A shown in claim 2.)

(In the formula, D and E represent coupler residues and may be the same or different. Specifically, they are defined in the same manner as the coupler residue A shown in claim 2).

[Wherein M represents a metal or, in the absence of a metal, two hydrogen atoms. ] In an electrophotographic photoreceptor comprising at least a charge generating material and a charge transport material on a conductive support, the outermost layer contains particles of a graft copolymer having a core / shell structure. Ri α- -phenylstilbene derivative der represented by the formula (15),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

(In the formula, n is an integer of 0 or 1, Ar ⁵ and Ar ⁶ are substituted or unsubstituted aryl groups [except at the same time when they are unsubstituted phenyl groups], or groups that jointly form a ring. Ar ⁷ represents a substituted or unsubstituted aryl group, R ¹⁶ , R ¹⁷ and R ¹⁸ represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, the aryl group and The substituent of the arylene group is an alkoxy group, a phenoxy group, an alkyl group, a hydroxy group, a halogen atom, a cyano group, or a nitro group. 12. The electrophotographic photoreceptor according to claim 11, wherein the α-phenylstilbene derivative is an α-phenylstilbene derivative represented by the following general formula (16).

(In the formula, R ¹⁹ represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom.) In an electrophotographic photoreceptor comprising at least a charge generating material and a charge transport material on a conductive support, the outermost layer contains particles of a graft copolymer having a core / shell structure. Ri benzidine compound der of the formula (17),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

(In the formula, R ²⁰ represents a lower alkyl group, a lower alkoxy group or a halogen atom, R ²¹ and R ²² may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom; h, l and m represent an integer of 0 to 4) In an electrophotographic photoreceptor including at least a charge generation material and a charge transport material on a conductive support, the outermost layer contains particles of a graft copolymer having a core / shell structure, and the charge transport material includes: Ri Ah charge transport polymer having a triarylamine structure represented by the following general formula (18),
The particles of the graft copolymer having the core / shell structure are obtained by polymerizing one or two or more kinds of vinyl monomers on an acrylic-silicone composite rubber-like polymer in one stage or in multiple stages by a radical polymerization technique. electrophotographic photoreceptor according to claim Monodea Rukoto.

[Wherein Ar ¹ , Ar ² and Ar ³ represent a substituted or unsubstituted arylene group. R ¹ and R ² represent the same or different acyl groups, substituted or unsubstituted alkyl groups, and substituted or unsubstituted aryl groups. k is an integer of 5 to 5000, j is an integer of 5 to 5000, and 0 <k / (k + j) ≦ 1. X is a substituted or unsubstituted aliphatic divalent group, a substituted or unsubstituted cyclic aliphatic divalent group, a substituted or unsubstituted aromatic divalent group, or a divalent group formed by linking these, or the following formula: Indicates what is represented. ]

(Wherein R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a halogen atom. A and b are each independently 0 C and d are each independently an integer of 0 to 3, and when there are a plurality of R ³ , R ⁴ , R ⁵ and R ⁶ , they may be the same or different. Y is a single bond, a linear alkylene group having 2 to 12 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 12 carbon atoms, or one or more alkylene groups having 1 to 10 carbon atoms. And a divalent group composed of one or more oxygen atoms and sulfur atoms, -O-, -S-, -SO-, -SO _2- , -CO-, -COO-, or

Z ¹ and Z ² represent a substituted or unsubstituted aliphatic divalent group or a substituted or unsubstituted arylene group, R ⁷ and R ¹⁴ represent a halogen atom, a substituted or unsubstituted alkyl group, a substituted Or an unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted group. An alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryl group is represented. R ⁸ and R ⁹ may combine to form a carbocyclic ring having 5 to 12 carbon atoms, R ¹⁵ and R ¹⁶ represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ¹⁷ and R ¹⁸ Each independently represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, e and g are integers of 0 to 4, f is 1 or 2, h is an integer of 0 to 20, and i is 0 Represents an integer of ~ 2000. )

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