JP3684088B2 - Electrophotographic photosensitive member, process cartridge having the electrophotographic photosensitive member, and electrophotographic apparatus - Google Patents

Description

（式（１）中、Ｒ _１ 乃至Ｒ _５ は、同一または異なって、水素原子、フッ素原子または置換もしくは無置換のアルキル基を示し、Ｒ _６ 乃至Ｒ _８ は、同一または異なって、水素原子または置換もしくは無置換のアルキル基を示す。）
【００１８】
また、本発明は、上記電子写真感光体を有するプロセスカートリッジ及び電子写真装置である。
【００１９】
【発明の実施の形態】
本発明に用いられるポリフェニレン樹脂とは、重合体の主鎖が置換基として様々な有機基を有しても良いフェニレンを繰り返し構成単位とする樹脂である。
【００２０】
本発明に用いるポリフェニレン樹脂は、主鎖の構造がポリフェニレンン構造であるため、高い結晶性を有し、高分子膜を形成する際、剛直な構造となるため機械的強度が高く、また広い共役系を有しているため電気的にも強いものと考えられる。
【００２１】
本発明においては、電子写真特性及び溶解性の点で、ポリフェニレン樹脂が下記式（１）で示される構成単位を有することが好ましい。
【００２２】
【外３】

（式中、Ｒ₁ 乃至Ｒ₅ は同一または異なって、水素原子、フッ素原子または置換もしくは無置換のアルキル基を示し、Ｒ₆ 乃至Ｒ₈ は同一または異なって、水素原子または置換もしくは無置換のアルキル基を示す。）
式（１）において、アルキル基としてはメチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ターシャリーブチル基、ヘキシル基及びオクチル基などが挙げられる。アルキル基が有してもよい置換基としては、フッ素原子、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ターシャリブチル基、ヘキシル基及びオクチル基などのアルキル基、フェニル基及びナフチル基などのアリール基が挙げられる。
【００２３】
なお、本発明においては、機械的強度の点で、Ｒ₆ 乃至Ｒ₈ の、更には、Ｒ₁ 乃至Ｒ₈ の全てが水素原子であることが好ましい。
【００２４】
また、本発明においては、ポリフェニレン樹脂が式（１）で示される構成単位を２種以上有していてもよい。
【００２５】
更に、本発明においては、ポリフェニレン樹脂が式（１）以外の構成単位を有していてもよい。この場合、式（１）で示される構成単位が全構成単位に対し２０ｍｏｌ％以上であることが好ましく、特には４０ｍｏｌ％以上であることが好ましい。
【００２６】
特に、本発明においては、溶解性の点で、ポリフェニレン樹脂が下記式（２）で示される構成単位を有することが好ましい。
【００２７】
【外４】

（式中、Ｒ₉ 乃至Ｒ₁₃は同一または異なって、水素原子、フッ素原子または置換もしくは無置換のアルキル基を示し、Ｒ₁₄乃至Ｒ₂₀は同一または異なって、水素原子または置換もしくは無置換のアルキル基を示し、ｍ及びｎは共重合比を示す。）
式（２）中、アルキル基及びアルキル基が有してもよい置換基としては式（１）と同様のものが挙げられる。
【００２８】
本発明においては、強度の点で、Ｒ₁₄乃至Ｒ₂₀の、更には、Ｒ₉ 乃至Ｒ₂₀が全て水素原子であることが好ましい。また、ｍ：ｎは２０：８０〜８０：２０であることが好ましく、特には４０：６０〜６０：４０であることが好ましい。
【００２９】
本発明のポリフェニレン樹脂の重量平均分子量（Ｍｗ）は、１０，０００〜５００，０００であることが好ましい。
【００３０】
なお、本発明においては、ポリフェニレン樹脂を他の樹脂、例えば、ポリカーボネート樹脂やポリアリレート樹脂と混合して用いてもよい。この場合、本発明のポリフェニレン樹脂が樹脂全重量の２０重量％以上、特には６０重量％以上であることが好ましい。
【００３１】
以下に、本発明のポリフェニレン樹脂が有する構成単位の好ましい例を挙げるが、本発明はこれらの例に限定されるものではない。
【００３２】
【外５】

【００３３】
【外６】

【００３４】
【外７】

【００３５】
これらの中では、構成単位例（１）及び（１３）が特に好ましい。
【００３６】
合成例１（構成単位例（１）を有するポリフェニレン樹脂の合成）
テトラヒドロフラン１０ｍｌ中に亜鉛粉末１．３ｇ（０．０２ｍｏｌ）を含む溶液に、テトラヒドロフラン３０ｍｌ中に２，５―ジクロロベンゾフェノン２．５ｇ（０．０１ｍｏｌ）を含む溶液をアルゴン下で加えた。
【００３７】
混合物を１時間撹拌後、この溶液にＮｉＣｌ₂ ビピリジン０．０５ｇ（０．１８ｍｍｏｌ）を加え、２４時間還流した。放冷後、２００ｍｌのエタノールに反応液を注ぎ、沈殿物（合成したポリマー）を濾取した。乾燥後の収量は１．４ｇ（収率７７．７％）であった。
【００３８】
合成例２（構成単位例（１３）を有するポリフェニレン樹脂の合成）
テトラヒドロフラン２０ｍｌ中に亜鉛粉末２．６ｇ（０．０４ｍｏｌ）を含む溶液に、テトラヒドロフラン３０ｍｌ中に２，５―ジクロロベンゾフェノン２．５ｇ（０．０１ｍｏｌ）と１，４−ジクロロベンゼン１．５ｇ（０．０１ｍｏｌ）を含む溶液を、アルゴン下で加えた。
【００３９】
混合物を１時間撹拌後、この溶液にＮｉＣｌ₂ ビピリジン０．１０ｇ（０．３６ｍｍｏｌ）を加え、２４時間還流した。放冷後、３００ｍｌのエタノールに反応液を注ぎ、沈殿物（合成したコポリマー）を濾取した。乾燥後の収量は２．２ｇ（収率８５．９％）であった。
【００４０】
上記以外の構成単位例を有するポリフェニレン樹脂も上記と同様の方法によって得ることができる。
【００４１】
本発明の電子写真感光体の表面層は、感光層である場合と感光層上の保護層である場合に大別される。
【００４２】
表面層が感光層である場合、感光層が電荷発生材料と電荷輸送材料を同一の層に含有する単一層型であるときには、その層が表面層である。
【００４３】
また、感光層が、電荷発生材料を含有する電荷発生層上に電荷輸送材料を含有する電荷輸送層を有する積層型である場合は、電荷輸送層が表面層であり、逆に電荷発生層が上層である場合には、電荷発生層が表面層である。
【００４４】
本発明においては、電荷輸送層が表面層であることが、電子写真特性の点から好ましい。
【００４５】
電荷輸送層は、電荷輸送材料とバインダー樹脂とを溶剤中に溶解した溶液を塗布し、乾燥することによって形成することができる。用いられる電荷輸送材料としては、トリアリールアミン系化合物、ヒドラゾン化合物、スチルベン化合物、ピラゾリン系化合物、オキサゾール系化合物、トリアリルメタン系化合物及びチアゾール系化合物などが挙げられる。バインダー樹脂としては、電荷輸送層が表面層である場合は、本発明のポリフェニレン樹脂が、表面層でない場合は、各種樹脂が挙げられる。電荷輸送材料とバインダー樹脂の割合は、重量比で１：０．５〜１：２であることが好ましい。また、電荷輸送層の膜厚は、５〜４０μｍであることが好ましく、１５〜３０μｍであることがより好ましい。
【００４６】
電荷発生層は、電荷発生材料を０．３〜４倍の重量のバインダー樹脂及び溶剤と共にホモジナイザー、超音波分散、ボールミル、振動ボールミル、サンドミル、アトライター、ロールミル及び液衝突型高速分散機などの方法でよく分散した分散液を塗布し、乾燥することによって形成することができる。用いられる電荷発生材料としては、セレン−テルル、ピリリウム、チアピリリウム系染料、フタロシアニン、アントアントロン、ジベンズピレンキノン、トリスアゾ、シアニン、ジスアゾ、モノアゾ、インジゴ、キナクリドン及び非対称キノシアニン系などの各顔料が挙げられる。バインダー樹脂としては、電荷発生層が表面層の場合は、本発明のポリフェニレン樹脂が、表面層でない場合には、各種樹脂が挙げられる。また、電荷発生層の膜厚は、５μｍ以下であることが好ましく、０．１〜２μｍであることがより好ましい。
【００４７】
感光層が単一層型の場合は、上記電荷発生材料及び電荷輸送材料をバインダー樹脂に分散及び溶解した溶液を塗布し、乾燥することによって形成することができる。膜厚は、５〜４０μｍであることが好ましく、１５〜３０μｍであることがより好ましい。
【００４８】
保護層は、本願発明のポリフェニレン樹脂及び必要に応じて、有機物または無機物の抵抗制御剤を含有する溶液を塗布し、乾燥することによって形成することができる。保護層の膜厚は、０．５〜１０μｍであることが好ましく、１〜５μｍであることがより好ましい。
【００４９】
本発明に用いられる支持体は導電性を有するものであればよく、アルミニウム及びステンレスなどの金属、あるいは導電層を設けた金属、紙及びプラスチックなどが挙げられ、形状はシート状及び円筒状などが挙げられる。
【００５０】
本発明においては、支持体と感光層の間に、干渉縞の防止や支持体の傷の被覆を目的として導電層を設けてもよい。かかる導電層はカーボンブラック、金属粒子及び金属酸化物粒子などの導電性粒子をバインダー樹脂に分散した溶液を塗布し、乾燥することによって形成することができる。導電層の膜厚は５〜４０μｍであることが好ましく、１０〜３０μｍであることがより好ましい。
【００５１】
また、本発明においては、支持体と感光層の間に、接着機能及びバリア機能を有する中間層を設けることができる。中間層の材料としてはポリアミド、ポリビニルアルコール、ポリエチレンオキシド、エチルセルロース、カゼイン、ポリウレタン及びポリエーテルウレタンなどが挙げられる。これらを適当な溶剤に溶解した溶液を塗布し、乾燥することによって形成することができる。中間層の膜厚は、０．０５〜５μｍであることが好ましく、０．３〜１μｍであることがより好ましい。
【００５２】
図１に本発明の電子写真感光体を有するプロセスカートリッジを有する電子写真装置の概略構成を示す。
【００５３】
図において、１はドラム状の本発明の電子写真感光体であり、軸２を中心に矢印方向に所定の周速度で回転駆動される。感光体１は、回転過程において、一次帯電手段３によりその周面に正または負の所定電位の均一帯電を受け、次いで、スリット露光やレーザービーム走査露光などの露光手段（不図示）からの露光光４を受ける。こうして感光体１の周面に静電潜像が順次形成されていく。
【００５４】
形成された静電潜像は、次いで現像手段５によりトナー現像され、現像されたトナー現像像は、不図示の給紙部から感光体１と転写手段６との間に感光体１の回転と同期取り出されて給紙された転写材７に、転写手段６により順次転写されていく。
【００５５】
像転写を受けた転写材７は、感光体面から分離されて像定着手段８へ導入されて像定着を受けることにより複写物（コピー）として装置外へプリントアウトされる。
【００５６】
像転写後の感光体１の表面は、クリーニング手段９によって転写残りトナーの除去を受けて清浄面化され、更に前露光手段（不図示）からの前露光光１０により除電処理された後、繰り返し画像形成に使用される。なお、一次帯電手段３が帯電ローラーなどを用いた接触帯電手段である場合は、前露光は必ずしも必要ではない。
【００５７】
本発明においては、上述の電子写真感光体１、一次帯電手段３、現像手段５及びクリーニング手段９などの構成要素のうち、複数のものをプロセスカートリッジとして一体に結合して構成し、このプロセスカートリッジを複写機やレーザービームプリンターなどの電子写真装置本体に対して着脱可能に構成してもよい。例えば、一次帯電手段３、現像手段５及びクリーニング手段９の少なくとも１つを感光体１と共に一体に支持してカートリッジ化して、装置本体のレール１２などの案内手段を用いて装置本体に着脱可能なプロセスカートリッジ１１とすることができる。
【００５８】
また、露光光４は、電子写真装置が複写機やプリンターである場合には、原稿からの反射光や透過光、あるいは、センサーで原稿を読取り、信号化し、この信号に従って行われるレーザービームの走査、ＬＥＤアレイの駆動及び液晶シャッターアレイの駆動などにより照射される光である。
【００５９】
本発明の電子写真感光体は電子写真複写機に利用するのみならず、レーザービームプリンター、ＣＲＴプリンター、ＬＥＤプリンター、液晶プリンター及びレーザー製版など電子写真応用分野にも広く用いることができる。
【００６０】
【実施例】
以下、実施例に従って本発明をより詳細に説明する。なお、実施例中「部」は重量部を表す。
【００６１】
〔実施例１〕
３０ｍｍφ×３５７ｍｍのアルミニウムシリンダー上に、以下の材料より構成される溶液を浸漬コーティング法によって塗布し、１４０℃で３０分熱硬化することによって、膜厚が１５μｍの導電層を形成した。
【００６２】
導電性顔料：ＳｎＯ₂ コート処理硫酸バリウム １０部
抵抗調節用顔料：酸化チタン ２部
バインダー樹脂：フェノール樹脂 ６部
レベリング材：シリコーンオイル ０．００１部
溶剤：メタノール／メトキシプロパノール（０．２／０．８） ２０部
【００６３】
次に、この層の上にＮ−メトキシメチル化ナイロン３部及び共重合ナイロン３部を、メタノール６５部及びｎ−ブタノール３０部の混合溶媒に溶解した溶液を浸漬コーティング法で塗布し、乾燥することによって、膜厚が０．５μｍの中間層を形成した。
【００６４】
次に、ＣｕＫα特性Ｘ線回折におけるブラッグ角２θ±０．２°の９．０°、１４．２°、２３．９°及び２７．１°に強いピークを有するオキシチタニウムフタロシアニン４部、ポリビニル（ｐ−フッ素）ベンザール２部及びシクロヘキサノン６０部を混合した溶液を１ｍｍφガラスビーズを用いたサンドミル装置で３時間分散した後、エチルアセテート１００部を加えて電荷発生層用分散液を調製した。この液を中間層上に浸漬コーティング法で塗布し、乾燥することによって、膜厚が０．２μｍの電荷発生層を形成した。
【００６５】
次に、下記式で示されるトリアリールのアミン化合物９部、
【００６６】
【外８】

下記式で示されるスチルベン化合物１部
【００６７】
【外９】

及び下記式で示される構成単位を有するポリフェニレン樹脂（Ｍｗ≒５０，０００）１２．５部
【００６８】
【外１０】

を、モノクロロベンゼン５０部及びジクロロメタン５０部の混合溶媒に溶解した。
【００６９】
この溶液を電荷発生層上に浸漬コーティング法で塗布し、１１０℃で１時間乾燥することによって、膜厚が２３μｍの電荷輸送層を形成した。
【００７０】
作成した電子写真感光体をＡＣ電圧を重畳したローラ接触帯電手段（ＡＣ／ＤＣ接触帯電手段）を有する複写機「ＧＰ−２１５」（キヤノン（株）製）に取り付け、温度２３℃、湿度５０％ＲＨの常温常湿環境下で暗部電位Ｖｄ、感度ＥΔ５００及び残留電位Ｖｒを測定した。ＧＰ−２１５には、感光体の電子写真特性を測定するための改造を施した。
【００７１】
暗部電位Ｖｄは絶対値が大きい程帯電能が良いことを示し、感度ＥΔ５００は−７００Ｖから−２００Ｖに電位を減衰させるのに必要な光量で、値が小さい程感度が良いことを示す。
【００７２】
更に、常温常湿下で５０，０００枚の通紙耐久試験を行い、初期、３０，０００枚後及び５０，０００枚後の暗部電位Ｖｄ、感度ＥΔ５００及び残留電位Ｖｒを測定した。また、３０，０００枚後及び５０，０００後の摩耗量を測定した。耐久試験は１枚毎に一回停止する間欠モードとし、摩耗量の測定にはフィッシャー社製渦電流式膜厚測定機（パーマスコープ タイプＥ１１１）を用いた。
【００７３】
更に、表面に指脂を付着させ４８時間放置し、顕微鏡観察によりソルベントクラックの有無を確認した。○はソルベントクラックが認められないことを示し、×はソルベントクラックが認められたことを示す。
【００７４】
結果を表１に示す。
【００７５】
〔実施例２〕
電荷輸送層用バインダー樹脂として下記式で示される構成単位を有するポリフェニレン樹脂（Ｍｗ≒４０，０００）を用いた以外は、実施例１と同様にして感光体を作成し、評価した。
【００７６】
【外１１】

結果を表１に示す。
【００７７】
〔実施例３〕
電荷輸送層用バインダー樹脂として、構成単位例２を有するポリフェニレン樹脂を用いた以外は、実施例１と同様にして感光体を作成し、評価した。
【００７８】
結果を表１に示す。
【００７９】
〔実施例４〕
電荷輸送層用バインダー樹脂として、実施例１で用いたポリフェニレン樹脂とポリカーボネート樹脂（ユーピロンＺ−２００、三菱エンジニアリングプラスチック（株）製）の重量比で１：１の混合物を用いた以外は、実施例１と同様にして感光体を作成し、評価した。
【００８０】
結果を表１に示す。
【００８１】
〔比較例１〕
電荷輸送層用バインダーとしてポリカーボネート樹脂（ユーピロンＺ−２００、三菱エンジニアリングプラスチック（株）製）のみを用いた以外は、実施例１と同様にして感光体を作成し、評価した。
【００８２】
結果を表１に示す。
【００８３】
【表１】

【００８４】
〔実施例５〕
実施例１で作成した感光体をＡＣ／ＤＣ接触帯電手段を有するレーザービームプリンター「レーザージェット４Ｐｌｕｓ」（ヒューレットパッカード社製）の改造機に装着し、常温常湿下で、３，０００枚の通紙耐久試験を行い、摩耗量を測定した。また、目視による耐久後の画像評価も行った。その後、更に、温度３５℃、湿度８５％ＲＨの高温高湿環境下で画像に問題が生じるまで通紙耐久試験を行った。その際、トナーがなくなった場合は、トナーを補給して試験を続けた。なお、改造は、帯電時のピーク間電圧が２０％増加するように設定したことである。
【００８５】
耐久試験は１枚毎に一回停止する間欠モードとし、摩耗量の測定にはフィッシャー社製渦電流式膜厚測定機（パーマスコープ タイプＥ１１１）を用いた。
【００８６】
結果を表２に示す。
【００８７】
〔実施例６〕
実施例２で作成した感光体を実施例５と同様の方法で評価した。
【００８８】
結果を表２に示す。
【００８９】
〔比較例２〕
比較例１で作成した感光体を実施例５と同様の方法で評価した。
【００９０】
結果を表２に示す。
【００９１】
〔実施例７〕
実施例１で作成した感光体をコロナ帯電手段を有する複写機「ＧＰ−５５」（キヤノン製）に装着し、常温常湿下で、３０，０００枚の通紙耐久試験を行い、摩耗量を測定した。また、目視による耐久後の画像評価も行った。その後、更に、温度３５℃、湿度８５％ＲＨの高温高湿環境下で画像に問題が生じるまで通紙耐久試験を行った。その際、トナーがなくなった場合は、トナーを補給して試験を続けた。
【００９２】
耐久試験は１枚毎に一回停止する間欠モードとし、摩耗量の測定はフィッシャー社製渦電流膜厚測定機（パーマスコープ タイプＥ１１１）を用いた。
【００９３】
結果を表２に示す。
【００９４】
〔実施例８〕
実施例２で作成した感光体を実施例７と同様の方法で評価した。
【００９５】
結果を表２に示す。
【００９６】
〔比較例３〕
比較例１で作成した感光体を実施例７と同様の方法で評価した。
【００９７】
結果を表２に示す。
【００９８】
〔実施例９〕
実施例１と同様にして、アルミニウムシリンダー上に導電層及び中間層を形成した。
【００９９】
次に、下記で示されるアゾ顔料４部、
【０１００】
【外１２】

【０１０１】
ポリビニル（ｐ−フッ素）ベンザール２部及びテトラヒドロフラン１２０部を混合した溶液１ｍｍφガラスビーズを用いたサンドミル装置で２０時間分散した後、シクロヘキサノン７０部を加えて電荷発生層用分散液を調製した。この液を中間層上に浸漬コーティング法で塗布し、乾燥することによって、膜厚が０．３μｍの電荷発生層を形成した。
【０１０２】
次に、ポリフェニレン樹脂の重量平均分子量を２０，０００にした以外は、実施例１と同様にして電荷輸送層を形成した。
【０１０３】
作成した電子写真感光体をＤＣ電圧のみのローラ接触帯電手段（ＤＣ接触帯電手段）を有する複写機「ＮＰ−６０３０」（キヤノン（株）製）に装着し、常温常湿下で、３０，０００枚の通紙耐久試験を行い、摩耗量を測定した。また、目視による耐久後の画像評価も行った。その後、更に、温度３５℃、湿度８５％ＲＨの高温高湿環境下で画像に問題が生じるまで通紙耐久試験を行った。その際、トナーがなくなった場合は、トナーを補給して試験を続けた。
【０１０４】
耐久試験は１枚毎に一回停止する間欠モードとし、摩耗量の測定にはフィッシャー社製渦電流式膜厚測定機（パーマスコープ タイプＥ１１１）を用いた。
【０１０５】
結果を表２に示す。
【０１０６】
〔実施例１０〕
電荷輸送層用バインダー樹脂として下記式で示される構成単位を有するポリフェニレン樹脂（Ｍｗ≒６０，０００）を用いた以外は、実施例９と同様にして感光体を作成し、評価した。
【０１０７】
【外１３】

【０１０８】
結果を表２に示す。
【０１０９】
〔比較例４〕
ポリフェニレン樹脂の代わりにポリカーボネート樹脂（ユーピロンＺ−２００、三菱エンジニアリングプラスチックス（株）製）を用いた以外は、実施例９と同様にして感光体を作成し、評価した。
【０１１０】
結果を表２に示す。
【０１１１】
【表２】

【０１１２】
以上の結果から、本発明のポリフェニレン樹脂を用いた電子写真感光体は、電子写真特性及び耐ソルベントクラック性に優れ、特に放電量の多い系で耐久性に優れていることがわかる。このことは、本発明の電子写真感光体が機械的耐久性だけではなく、電気的耐久性にも優れていることを示している。
【０１１３】
【発明の効果】
以上のように、本発明によれば、電子写真特性に優れ、かつ耐ソルベントクラック性も良好であり、機械的強度及び接触帯電に対する耐電気特性にも優れた電子写真感光体、該電子写真感光体を有するプロセスカートリッジ及び電子写真装置を提供することが可能となった。
【図面の簡単な説明】
【図１】本発明の電子写真感光体を有するプロセスカートリッジを有する電子写真装置の概略構成の例を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus, and more specifically, an electrophotographic photosensitive member having a surface layer containing a specific resin, and a process having the electrophotographic photosensitive member. The present invention relates to a cartridge and an electrophotographic apparatus.
[0002]
[Prior art]
In recent years, electrophotographic photoreceptors (0PC photoreceptors) containing various organic photoconductive compounds have been actively developed. For example, US Pat. No. 3,378,851 discloses a photoreceptor having a charge transport layer containing triarylpyrazoline, and US Pat. No. 3,871,880 discloses a charge generation layer containing a derivative of perylene pigment, 3-propylene and formaldehyde. A photoreceptor having a charge transport layer containing a condensate is disclosed.
[0003]
Organic photoconductive compounds have different photosensitivity wavelength ranges depending on the compound. For example, JP-A-61-272754 and JP-A-56-167759 disclose azo pigments having high sensitivity in the visible region. JP-A-57-19576 and JP-A-61-228453 disclose compounds having high sensitivity in the infrared region.
[0004]
Of these materials, those showing sensitivity in the infrared region are used in laser beam printers and LED printers, and the frequency of their demand is increasing.
[0005]
On the other hand, as a matter of course, the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, mechanical characteristics, and optical characteristics according to the applied electrophotographic process.
[0006]
In particular, electrical and mechanical external forces such as charging, exposure, development, transfer, and cleaning are directly and repeatedly applied to the surface of the electrophotographic photosensitive member that is repeatedly used, and thus durability against them is required.
[0007]
Specifically, durability against electrical and mechanical deterioration such as deterioration due to ozone and nitrogen oxide generated during charging, and surface wear and scratches due to discharge and cleaning is required.
[0008]
In particular, since many OPC photoreceptors are materially soft compared to inorganic photoreceptors, durability against mechanical deterioration is particularly desired.
[0009]
Further, by applying a voltage to a charging member disposed in contact with an electrophotographic photosensitive member as disclosed in Japanese Patent Application Laid-Open Nos. 57-17826 and 58-40566, which are becoming mainstream in recent years, an electrophotographic photosensitive member is provided. There is also a problem that is particularly prominent in the contact charging method for charging the body. The contact charging method produces much less ozone than Scorotron, and around 80% of the current that Scorotron flows to the charger flows to the shield. It has a merit such as
[0010]
However, since the charging member is in contact with the electrophotographic photosensitive member, the electrophotographic photosensitive member is required to have better mechanical strength.
[0011]
In addition, since contact charging is also charging by discharge, it has been proposed to use a voltage obtained by superimposing an alternating current (AC) voltage on a direct current (DC) voltage as an applied voltage for the purpose of improving charging stability. (Japanese Unexamined Patent Publication No. 63-149668).
[0012]
[Problems to be solved by the invention]
However, although this charging method can improve the charging stability, the amount of current flowing to the electrophotographic photosensitive member is greatly increased due to the use of the AC voltage, and as a result, the amount of abrasion of the electrophotographic photosensitive member is increased. It becomes easy to do.
[0013]
As described above, the electrophotographic photosensitive member is required to have not only mechanical strength but also electrical strength.
[0014]
At the same time, durability against solvent cracks caused by adhesion of machine oil or finger grease is also required.
[0015]
An object of the present invention is to provide an electrophotographic photoreceptor having excellent mechanical durability, excellent electrical durability, and excellent solvent crack resistance.
[0016]
Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[0017]
[Means for Solving the Problems]
That is, the present invention relates to an electrophotographic photoreceptor having a support and a photosensitive layer formed on the support, wherein the surface layer of the electrophotographic photoreceptor has a structural unit represented by the following formula (1). An electrophotographic photosensitive member characterized by comprising:
[Chemical 3]

(In Formula (1), R _{1 to} R ₅ are the same or different and each represents a hydrogen atom, a fluorine atom or a substituted or unsubstituted alkyl group, and R _{6 to} R ₈ are the same or different and represent a hydrogen atom or A substituted or unsubstituted alkyl group is indicated.)
[0018]
The present invention also provides a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The polyphenylene resin used in the present invention is a resin in which the main chain of the polymer has phenylene which may have various organic groups as substituents, and has repeating structural units.
[0020]
The polyphenylene resin used in the present invention has a high crystallinity because the main chain structure is a polyphenylene structure, and has a high mechanical strength due to a rigid structure when a polymer film is formed. Because it has a system, it is considered to be electrically strong.
[0021]
In the present invention, it is preferable that the polyphenylene resin has a structural unit represented by the following formula (1) in view of electrophotographic characteristics and solubility.
[0022]
[Outside 3]

(Wherein R _{1 to} R ₅ are the same or different and each represents a hydrogen atom, a fluorine atom or a substituted or unsubstituted alkyl group; R _{6 to} R ₈ are the same or different and represent a hydrogen atom or a substituted or unsubstituted atom; Represents an alkyl group.)
In the formula (1), examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tertiary butyl group, a hexyl group, and an octyl group. The substituents that the alkyl group may have include alkyl groups such as fluorine atom, methyl group, ethyl group, propyl group, isopropyl group, butyl group, tertiary butyl group, hexyl group and octyl group, phenyl group and naphthyl group. And aryl groups such as groups.
[0023]
In the present invention, from the viewpoint of mechanical strength, it is preferable that R _{6 to} R ₈ , more preferably, all of R _{1 to} R ₈ are hydrogen atoms.
[0024]
Moreover, in this invention, the polyphenylene resin may have 2 or more types of structural units shown by Formula (1).
[0025]
Furthermore, in this invention, the polyphenylene resin may have structural units other than Formula (1). In this case, the structural unit represented by the formula (1) is preferably 20 mol% or more, particularly preferably 40 mol% or more, based on all the structural units.
[0026]
In particular, in the present invention, it is preferable that the polyphenylene resin has a structural unit represented by the following formula (2) from the viewpoint of solubility.
[0027]
[Outside 4]

(Wherein R _{9 to} R ₁₃ are the same or different and each represents a hydrogen atom, a fluorine atom or a substituted or unsubstituted alkyl group; R _{14 to} R ₂₀ are the same or different and represent a hydrogen atom or a substituted or unsubstituted group; Represents an alkyl group, and m and n represent a copolymerization ratio.)
In the formula (2), examples of the substituent that the alkyl group and the alkyl group may have include those similar to the formula (1).
[0028]
In the present invention, from the viewpoint of strength, it is preferable that R _{14 to} R ₂₀ , and further R _{9 to} R ₂₀ are all hydrogen atoms. M: n is preferably 20:80 to 80:20, and particularly preferably 40:60 to 60:40.
[0029]
The polyphenylene resin of the present invention preferably has a weight average molecular weight (Mw) of 10,000 to 500,000.
[0030]
In the present invention, the polyphenylene resin may be mixed with another resin, for example, a polycarbonate resin or a polyarylate resin. In this case, the polyphenylene resin of the present invention is preferably 20% by weight or more, particularly 60% by weight or more of the total weight of the resin.
[0031]
Although the preferable example of the structural unit which the polyphenylene resin of this invention has is given to the following, this invention is not limited to these examples.
[0032]
[Outside 5]

[0033]
[Outside 6]

[0034]
[Outside 7]

[0035]
Among these, structural unit examples (1) and (13) are particularly preferable.
[0036]
Synthesis Example 1 (Synthesis of polyphenylene resin having structural unit example (1))
To a solution containing 1.3 g (0.02 mol) of zinc powder in 10 ml of tetrahydrofuran, a solution containing 2.5 g (0.01 mol) of 2,5-dichlorobenzophenone in 30 ml of tetrahydrofuran was added under argon.
[0037]
After stirring the mixture for 1 hour, 0.05 g (0.18 mmol) of NiCl ₂ bipyridine was added to this solution and refluxed for 24 hours. After allowing to cool, the reaction solution was poured into 200 ml of ethanol, and the precipitate (synthesized polymer) was collected by filtration. The yield after drying was 1.4 g (yield 77.7%).
[0038]
Synthesis Example 2 (Synthesis of polyphenylene resin having structural unit example (13))
In a solution of 2.6 g (0.04 mol) of zinc powder in 20 ml of tetrahydrofuran, 2.5 g (0.01 mol) of 2,5-dichlorobenzophenone and 1.5 g of 1,4-dichlorobenzene (0. A solution containing 01 mol) was added under argon.
[0039]
After stirring the mixture for 1 hour, 0.10 g (0.36 mmol) of NiCl ₂ bipyridine was added to this solution and refluxed for 24 hours. After cooling, the reaction solution was poured into 300 ml of ethanol, and the precipitate (synthesized copolymer) was collected by filtration. The yield after drying was 2.2 g (yield 85.9%).
[0040]
Polyphenylene resins having structural unit examples other than those described above can also be obtained by the same method as described above.
[0041]
The surface layer of the electrophotographic photosensitive member of the present invention is roughly classified into a case where it is a photosensitive layer and a case where it is a protective layer on the photosensitive layer.
[0042]
When the surface layer is a photosensitive layer, when the photosensitive layer is a single layer type containing the charge generation material and the charge transport material in the same layer, the layer is the surface layer.
[0043]
In addition, when the photosensitive layer is a stacked type having a charge transport layer containing a charge transport material on a charge generation layer containing a charge generation material, the charge transport layer is a surface layer, and conversely In the case of the upper layer, the charge generation layer is a surface layer.
[0044]
In the present invention, the charge transport layer is preferably a surface layer from the viewpoint of electrophotographic characteristics.
[0045]
The charge transport layer can be formed by applying a solution obtained by dissolving a charge transport material and a binder resin in a solvent and drying the solution. Examples of the charge transport material used include triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, triallylmethane compounds, and thiazole compounds. Examples of the binder resin include a polyphenylene resin of the present invention when the charge transport layer is a surface layer, and various resins when the charge transport layer is not a surface layer. The ratio between the charge transport material and the binder resin is preferably 1: 0.5 to 1: 2 by weight. The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 15 to 30 μm.
[0046]
Charge generation layer is a method of homogenizer, ultrasonic dispersion, ball mill, vibration ball mill, sand mill, attritor, roll mill, liquid collision type high-speed disperser, etc. together with binder resin and solvent having a weight of 0.3 to 4 times the charge generation layer It can be formed by applying a well-dispersed dispersion and drying it. Examples of the charge generating material used include selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanine, anthanthrone, dibenzpyrenequinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine-based pigments. . As the binder resin, when the charge generation layer is a surface layer, the polyphenylene resin of the present invention may be various resins when the charge generation layer is not a surface layer. The film thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.1 to 2 μm.
[0047]
When the photosensitive layer is a single layer type, it can be formed by applying and drying a solution in which the charge generating material and the charge transporting material are dispersed and dissolved in a binder resin. The film thickness is preferably 5 to 40 μm, and more preferably 15 to 30 μm.
[0048]
The protective layer can be formed by applying and drying a solution containing the polyphenylene resin of the present invention and, if necessary, an organic or inorganic resistance control agent. The thickness of the protective layer is preferably 0.5 to 10 μm, and more preferably 1 to 5 μm.
[0049]
The support used in the present invention is not particularly limited as long as it has conductivity, and examples thereof include metals such as aluminum and stainless steel, metals provided with a conductive layer, paper, plastics, and the like. Can be mentioned.
[0050]
In the present invention, a conductive layer may be provided between the support and the photosensitive layer for the purpose of preventing interference fringes and covering the scratches on the support. Such a conductive layer can be formed by applying a solution in which conductive particles such as carbon black, metal particles, and metal oxide particles are dispersed in a binder resin, and drying. The thickness of the conductive layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.
[0051]
In the present invention, an intermediate layer having an adhesive function and a barrier function can be provided between the support and the photosensitive layer. Examples of the material for the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. It can be formed by applying a solution obtained by dissolving these in an appropriate solvent and drying. The thickness of the intermediate layer is preferably 0.05 to 5 μm, and more preferably 0.3 to 1 μm.
[0052]
FIG. 1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention.
[0053]
In the figure, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotated about a shaft 2 in the direction of an arrow at a predetermined peripheral speed. In the rotation process, the photosensitive member 1 is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the primary charging unit 3, and then exposed from an exposure unit (not shown) such as slit exposure or laser beam scanning exposure. Receive light 4. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor 1.
[0054]
The formed electrostatic latent image is then developed with toner by the developing unit 5, and the developed toner developed image is rotated between the photosensitive member 1 and the transfer unit 6 from a sheet feeding unit (not shown). The image is sequentially transferred by the transfer means 6 to the transfer material 7 that is synchronously taken out and fed.
[0055]
The transfer material 7 that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means 8, and subjected to image fixing, thereby being printed out as a copy (copy).
[0056]
After the image transfer, the surface of the photoreceptor 1 is cleaned by removing the transfer residual toner by the cleaning unit 9 and further subjected to charge removal processing by the pre-exposure light 10 from the pre-exposure unit (not shown), and then repeatedly. Used for image formation. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.
[0057]
In the present invention, a plurality of components such as the above-described electrophotographic photosensitive member 1, primary charging unit 3, developing unit 5, and cleaning unit 9 are integrally coupled as a process cartridge. May be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported with the photosensitive member 1 to form a cartridge, and can be attached to and detached from the apparatus main body using guide means such as a rail 12 of the apparatus main body. The process cartridge 11 can be obtained.
[0058]
Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 is reflected or transmitted light from the original, or the original is read by a sensor and converted into a signal, and a laser beam scanning performed according to this signal is performed. The light is emitted by driving the LED array and the liquid crystal shutter array.
[0059]
The electrophotographic photosensitive member of the present invention can be used not only in electrophotographic copying machines but also widely in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.
[0060]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “parts” represents parts by weight.
[0061]
[Example 1]
A solution composed of the following materials was applied on a 30 mmφ × 357 mm aluminum cylinder by a dip coating method and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.
[0062]
Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: Titanium oxide 2 parts Binder resin: Phenol resin 6 parts Leveling material: Silicone oil 0.001 part Solvent: Methanol / methoxypropanol (0.2 / 0. 8) 20 copies [0063]
Next, a solution obtained by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol is applied on this layer by a dip coating method and dried. As a result, an intermediate layer having a thickness of 0.5 μm was formed.
[0064]
Next, 4 parts of oxytitanium phthalocyanine having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction, polyvinyl ( A solution obtained by mixing 2 parts of (p-fluorine) benzal and 60 parts of cyclohexanone was dispersed in a sand mill apparatus using 1 mmφ glass beads for 3 hours, and then 100 parts of ethyl acetate was added to prepare a dispersion for charge generation layer. This solution was applied onto the intermediate layer by a dip coating method and dried to form a charge generation layer having a thickness of 0.2 μm.
[0065]
Next, 9 parts of a triaryl amine compound represented by the following formula:
[0066]
[Outside 8]

1 part of a stilbene compound represented by the following formula:
[Outside 9]

And 12.5 parts of a polyphenylene resin (Mw≈50,000) having a structural unit represented by the following formula:
[Outside 10]

Was dissolved in a mixed solvent of 50 parts of monochlorobenzene and 50 parts of dichloromethane.
[0069]
This solution was applied onto the charge generation layer by a dip coating method and dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 23 μm.
[0070]
The prepared electrophotographic photosensitive member is attached to a copying machine “GP-215” (manufactured by Canon Inc.) having roller contact charging means (AC / DC contact charging means) on which AC voltage is superimposed, and the temperature is 23 ° C. and the humidity is 50%. The dark portion potential Vd, sensitivity EΔ500, and residual potential Vr were measured in a room temperature and humidity environment of RH. GP-215 was modified to measure the electrophotographic characteristics of the photoreceptor.
[0071]
The dark portion potential Vd indicates that the charging capability is better as the absolute value is larger, and the sensitivity EΔ500 is the amount of light necessary to attenuate the potential from −700 V to −200 V, and the smaller the value is, the better the sensitivity is.
[0072]
Further, a 50,000 sheet passing durability test was performed under normal temperature and normal humidity, and the dark part potential Vd, sensitivity EΔ500, and residual potential Vr after 30,000 sheets and after 50,000 sheets were measured initially. Further, the amount of wear after 30,000 sheets and after 50,000 was measured. The durability test was an intermittent mode in which each sheet was stopped once, and an eddy current film thickness measuring machine (Permascope type E111) manufactured by Fischer was used to measure the amount of wear.
[0073]
Further, finger grease was attached to the surface and left for 48 hours, and the presence or absence of solvent cracks was confirmed by microscopic observation. A symbol indicates that no solvent crack is observed, and a symbol X indicates that a solvent crack is observed.
[0074]
The results are shown in Table 1.
[0075]
[Example 2]
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that a polyphenylene resin (Mw≈40,000) having a structural unit represented by the following formula was used as the binder resin for the charge transport layer.
[0076]
[Outside 11]

The results are shown in Table 1.
[0077]
Example 3
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the polyphenylene resin having the structural unit example 2 was used as the binder resin for the charge transport layer.
[0078]
The results are shown in Table 1.
[0079]
Example 4
Except that the mixture of the polyphenylene resin used in Example 1 and the polycarbonate resin (Iupilon Z-200, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) at a weight ratio of 1: 1 was used as the binder resin for the charge transport layer. 1 was prepared and evaluated.
[0080]
The results are shown in Table 1.
[0081]
[Comparative Example 1]
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that only a polycarbonate resin (Iupilon Z-200, manufactured by Mitsubishi Engineering Plastics) was used as the binder for the charge transport layer.
[0082]
The results are shown in Table 1.
[0083]
[Table 1]

[0084]
Example 5
The photoconductor prepared in Example 1 is mounted on a modified machine of a laser beam printer “Laser Jet 4 Plus” (manufactured by Hewlett Packard) having AC / DC contact charging means, and 3,000 sheets are passed under normal temperature and humidity. A paper durability test was conducted to measure the amount of wear. Moreover, the image evaluation after endurance by visual observation was also performed. Thereafter, a paper passing durability test was further conducted until a problem occurred in an image in a high temperature and high humidity environment of 35 ° C. and humidity 85% RH. At that time, if the toner runs out, the toner was replenished and the test was continued. The modification is that the peak-to-peak voltage during charging is set to increase by 20%.
[0085]
The durability test was an intermittent mode in which each sheet was stopped once, and an eddy current film thickness measuring machine (Permascope type E111) manufactured by Fischer was used to measure the amount of wear.
[0086]
The results are shown in Table 2.
[0087]
Example 6
The photoconductor prepared in Example 2 was evaluated in the same manner as in Example 5.
[0088]
The results are shown in Table 2.
[0089]
[Comparative Example 2]
The photoconductor prepared in Comparative Example 1 was evaluated in the same manner as in Example 5.
[0090]
The results are shown in Table 2.
[0091]
Example 7
The photoconductor prepared in Example 1 is mounted on a copying machine “GP-55” (manufactured by Canon) having corona charging means, and a 30,000 sheet passing durability test is performed at room temperature and humidity to determine the amount of wear. It was measured. Moreover, the image evaluation after endurance by visual observation was also performed. Thereafter, a paper passing durability test was further conducted until a problem occurred in an image in a high temperature and high humidity environment of 35 ° C. and humidity 85% RH. At that time, if the toner runs out, the toner was replenished and the test was continued.
[0092]
The durability test was an intermittent mode in which each sheet was stopped once, and the wear amount was measured using an eddy current film thickness measuring device (Permascope type E111) manufactured by Fischer.
[0093]
The results are shown in Table 2.
[0094]
Example 8
The photoconductor prepared in Example 2 was evaluated in the same manner as in Example 7.
[0095]
The results are shown in Table 2.
[0096]
[Comparative Example 3]
The photoconductor prepared in Comparative Example 1 was evaluated in the same manner as in Example 7.
[0097]
The results are shown in Table 2.
[0098]
Example 9
In the same manner as in Example 1, a conductive layer and an intermediate layer were formed on an aluminum cylinder.
[0099]
Next, 4 parts of an azo pigment shown below,
[0100]
[Outside 12]

[0101]
A dispersion in which 2 parts of polyvinyl (p-fluorine) benzal and 120 parts of tetrahydrofuran were mixed was dispersed in a sand mill using 1 mmφ glass beads for 20 hours, and then 70 parts of cyclohexanone was added to prepare a dispersion for a charge generation layer. This solution was applied onto the intermediate layer by a dip coating method and dried to form a charge generation layer having a thickness of 0.3 μm.
[0102]
Next, a charge transport layer was formed in the same manner as in Example 1 except that the weight average molecular weight of the polyphenylene resin was changed to 20,000.
[0103]
The prepared electrophotographic photosensitive member is mounted on a copying machine “NP-6030” (manufactured by Canon Inc.) having roller contact charging means (DC contact charging means) with only DC voltage, and is 30,000 at normal temperature and humidity. A sheet passing durability test was performed, and the amount of wear was measured. Moreover, the image evaluation after endurance by visual observation was also performed. Thereafter, a paper passing durability test was further conducted until a problem occurred in an image in a high temperature and high humidity environment at a temperature of 35 ° C. and a humidity of 85% RH. At that time, if the toner runs out, the toner was replenished and the test was continued.
[0104]
The durability test was an intermittent mode in which each sheet was stopped once, and an eddy current film thickness measuring machine (Permascope type E111) manufactured by Fischer was used to measure the amount of wear.
[0105]
The results are shown in Table 2.
[0106]
Example 10
A photoconductor was prepared and evaluated in the same manner as in Example 9 except that a polyphenylene resin (Mw≈60,000) having a structural unit represented by the following formula was used as the binder resin for the charge transport layer.
[0107]
[Outside 13]

[0108]
The results are shown in Table 2.
[0109]
[Comparative Example 4]
A photoconductor was prepared and evaluated in the same manner as in Example 9 except that polycarbonate resin (Iupilon Z-200, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was used instead of polyphenylene resin.
[0110]
The results are shown in Table 2.
[0111]
[Table 2]

[0112]
From the above results, it can be seen that the electrophotographic photosensitive member using the polyphenylene resin of the present invention is excellent in electrophotographic characteristics and solvent crack resistance, and particularly excellent in durability in a system with a large amount of discharge. This indicates that the electrophotographic photoreceptor of the present invention is excellent not only in mechanical durability but also in electrical durability.
[0113]
【The invention's effect】
As described above, according to the present invention, an electrophotographic photosensitive member having excellent electrophotographic characteristics, good solvent crack resistance, and excellent mechanical strength and electric resistance against contact charging, and the electrophotographic photosensitive member. It has become possible to provide a process cartridge and an electrophotographic apparatus having a body.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus having a process cartridge having an electrophotographic photosensitive member of the present invention.

Claims (8)

An electrophotographic photosensitive member having a support and a photosensitive layer formed on the support, wherein the surface layer of the electrophotographic photosensitive member contains a polyphenylene resin having a structural unit represented by the following formula (1). An electrophotographic photoreceptor.

(In Formula (1), R _{1 to} R ₅ are the same or different and each represents a hydrogen atom, a fluorine atom or a substituted or unsubstituted alkyl group, and R _{6 to} R ₈ are the same or different and represent a hydrogen atom or A substituted or unsubstituted alkyl group is indicated.) The electrophotographic photosensitive member according to claim 1, wherein all of R _{6 to} R _{8 in} the formula (1) are hydrogen atoms. The electrophotographic photosensitive member according to claim 1, wherein all of R _{1 to} R _{8 in} the formula (1) are hydrogen atoms. The electrophotographic photosensitive member according to claim 1, wherein the polyphenylene resin has a structural unit represented by the following formula (2) .

(In the formula (2) , R _{9 to} R ₁₃ are the same or different and each represents a hydrogen atom, a fluorine atom or a substituted or unsubstituted alkyl group, and R _{14 to} R ₂₀ are the same or different and represent a hydrogen atom or a substituted or unsubstituted alkyl group, m and n denotes the copolymerization ratio.) The electrophotographic photosensitive member according to claim 4, wherein all of R _{14 to} R _{20 in} the formula (2) are hydrogen atoms. The electrophotographic photosensitive member according to claim 4, wherein all of R _{9 to} R _{20 in} the formula (2) are hydrogen atoms. An electrophotographic photosensitive member according to any one of claims 1 to 6, strip conductor means, and at least one means selected from the group consisting of the developing means and cleaning means integrally supported, detachably attached to an electrophotographic apparatus main body Process cartridge characterized by being. The electrophotographic photosensitive member according to any one of claims 1 to 6, a charging means, an exposure means, the electrophotographic apparatus, characterized in that it comprises a developing means and a transfer means.

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