JP2004093799A - Electrophotographic photoreceptor, process cartridge, and electrophotographic system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photorecepor which has high mechanical strength such as wear resistance and scratch resistance and has excellent stability in repeated use, and to provide a process cartridge and an electrophotographic system which have such an electrophotographic photoreceptor. <P>SOLUTION: In the electrophotographic photoreceptor having a photoreceptive layer on a support, the surface layer of the photoreceptive layer contains an electrically insulating binder resin and a random-copolymer-type high-molecular-weight charge-transport-substance having a specific structure. <P>COPYRIGHT: (C)2004,JPO

Description

【００１６】
（式（１）中、Ａｒ^１１、Ａｒ^１２、Ａｒ^１３は同一の構造であり、フェニル基以外の、置換または無置換の２価の芳香族炭化水素環基を示す。Ａｒ^１４、Ａｒ^１５、Ａｒ^１６は、それぞれ独立に、置換または無置換の芳香族炭化水素環基、または、置換または無置換の芳香族複素環基を示す。ただし、Ａｒ^１４およびＡｒ^１５の少なくとも一方は電子吸引性基を有する。ｋ、ｍ、ｎは、共重合比を意味し、ｋ、ｍは、１以上の整数であり、ｎは、０以上の整数である。）
【００１７】
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および電子写真装置である。
【００１８】
【発明の実施の形態】
以下、本発明をより詳細に説明する。
【００１９】
本発明においては、電子写真感光体の感光層に含有させる高分子量電荷輸送物質の構造を、便宜上、Ａｒ^１１およびＡｒ^１２を有する繰り返し構造単位の数をｋ、Ａｒ^１２およびＡｒ^１５を有する繰り返し構造単位の数をｍ、Ａｒ^１３およびＡｒ^１６を有する繰り返し構造単位の数をｎとして、上記式（１）で示した。
【００２０】
しかしながら、本発明で使用する高分子量電荷輸送物質は、２元共重合体および３元共重合体に限定されるものではなく、本発明の効果を損なわない範囲で、第４またはそれ以上の繰り返し構造単位を導入しても構わない。つまり、上記式（１）中のＡｒ^１３およびＡｒ^１６を有する繰り返し構造単位が複数種あっても構わない。本発明の効果を損なわないという観点からは、Ａｒ^１１およびＡｒ^１２を有する繰り返し構造単位の数（ｋ）と、Ａｒ^１２およびＡｒ^１５を有する繰り返し構造単位の数（ｍ）の和（ｋ＋ｍ）の、高分子量電荷輸送物質が有する繰り返し構造単位の全数（ｓｕｍ）に対する比の値（（ｋ＋ｍ）／ｓｕｍ）は、５０／１００〜１００／１００が好ましく、７５／１００〜１００／１００がより好ましい。
【００２１】
また、上記式（１）は、あたかも高分子量電荷輸送物質がブロック共重合体に限定されるかのような構造式であるが、本発明の電子写真感光体の感光層に含有させる高分子量電荷輸送物質の構造は、あくまで各繰り返し構造単位がランダムに存在するランダム共重合体であり、ｋ、ｍ、ｎは、共重合比を意味するに過ぎない（ただし、ｋ、ｍは、１以上の整数であり、ｎは、０以上の整数である。）。
【００２２】
本発明におけるランダム共重合体とは、作為的に交互共重合体またはブロック共重合体のような規則性を持った重合反応を起こさせるような操作をせず、後述の合成例に示すように、共重合体合成反応時に２種類以上の単量体（モノマー）原料を同時に反応容器内に投入し、反応させることで得られる共重合体のことを意味する（通常、こうした合成法で合成された高分子体はランダム共重合体になっていると考えられる。）。そして、ランダム共重合体型高分子量電荷輸送物質とは、ランダム共重合体を合成する上記方法により合成された高分子量電荷輸送物質のことを意味する。
【００２３】
各種共重合体の構造は次のとおりである。
【００２４】
繰り返し構造単位をＡおよびＢとしたときに、ランダム共重合体とは、ＡＡＡＢＡＡ、ＡＢＡＢＢＡ、ＡＡＢＢＡＢＡなど不規則に配列したものであり、交互共重合体とは、ＡＢＡＢＡＢと規則的に交互に配列しているものであり、ブロック共重合体とは、ＡＡＡＢＢＢ、ＡＡＡＡＡＢＢＢＢなど各繰り返し構造単位ごとの長さは様々だが、各繰り返し構造単位がブロックとして存在しているものである。
【００２５】
上記式（１）中のＡｒ^１１、Ａｒ^１２およびＡｒ^１３は、下記式（２１）で示される構造を有する２価の基であることが好ましい。
【外４】

【００２６】
上記芳香族炭化水素環基としては、ナフタレン、アントラセン、ペリレン、フルオレン、ビフェニル、ターフェニルなどから水素原子を１つ取り除いた１価の基が挙げられ、上記芳香族複素環基としては、カルバゾール、フラン、ベンゾフラン、チオフェン、ベンゾチオフェン、キノリン、フェナジン、ジベンゾチオフェン、ジベンゾフラン、カルバゾールなどから水素原子を１つ取り除いた１価の基が挙げられる。
【００２７】
また、上記２価の芳香族炭化水素環基としては、ナフタレン、アントラセン、ペリレン、フルオレン、ビフェニル、ターフェニルなどから水素原子を２つ取り除いた２価の基が挙げられ、上記２価の芳香族複素環基としては、カルバゾール、フラン、ベンゾフラン、チオフェン、ベンゾチオフェン、キノリン、フェナジン、ジベンゾチオフェン、ジベンゾフラン、カルバゾールなどから水素原子を２つ取り除いた２価の基が挙げられる。
【００２８】
また、上記アルキル基としては、メチル基、エチル基などが挙げられる。
【００２９】
また、上記各基が有してもよい置換基としては、メチル基、エチル基、プロピル基およびブチル基などのアルキル基や、メトキシ基、エトキシ基およびプロポキシ基などのアルコキシ基や、フェノキシ基およびナフトキシ基などのアリールオキシ基や、フッ素原子、塩素原子および臭素原子などのハロゲン原子や、ジメチルアミノ基、ジエチルアミノ基およびジフェニルアミノ基などのジ置換アミノ基などが挙げられる。
【００３０】
上記式（１）で示される構造を有するランダム共重合体型高分子量電荷輸送物質の、電子吸引性基を有さない側鎖の数（Ｂ）の電子吸引性基を有する側鎖の数（Ａ）に対する比の値（Ｂ／Ａ）は、２以上４０以下であることが好ましい。
【００３１】
上記式（１）中のｎは０であること、すなわち、上記式（１）で示される構造を有するランダム共重合体型高分子量電荷輸送物質は、２元共重合体であることが好ましい。
【００３２】
また、ｋのｍに対する比の値（ｋ／ｍ）は、１以上３０以下であることがより好ましい。
【００３３】
上記式（１）で示される構造を有するランダム共重合体型高分子量電荷輸送物質の重量平均分子量（Ｍｗ）は、１５００以上であることが好ましく、９０００以下であることがより好ましい。一方、５０００以下であることが好ましく、３０００以下であることがより好ましい。
【００３４】
本発明で使用するランダム共重合体型高分子量電荷輸送物質を構成する繰り返し構造単位の例を以下に示すが、本発明は、これらに限定されるものではない。
【００３５】
【外５】

【００３６】
【外６】

【００３７】
【外７】

【００３８】
【外８】

【００３９】
【外９】

【００４０】
【外１０】

【００４１】
【外１１】

【００４２】
次に、本発明で使用するランダム共重合体型高分子量電荷輸送物質の構造例を以下に示すが、本発明は、これらに限定されるものではない。
【００４３】
【表１】

【００４４】
これらの中でも、ＣＴＰ−３、６、９、１２、１３が好ましく、ＣＴＰ−３、１２がより好ましい。
【００４５】
本発明の電子写真感光体の感光層の表面層に含有させる電荷輸送物質は高分子量であるため、電荷輸送物質を添加することによる膜強度の低下が小さく、耐キズ、耐摩耗性に優れる。
【００４６】
さらに、２種類以上の繰り返し構造単位を有し、かつ、電子吸引性基を有する繰り返し構造単位を有する共重合体は、単一の繰り返し構造単位を有する単独重合体や、電子吸引性基を有する繰り返し構造単位を有さない重合体に比べ、電荷輸送物質のイオン化ポテンシャルの低下が小さく抑えられ、放電などによる酸化に対しても強いため、繰り返し使用による材料の劣化がほとんどないなどの特徴を有する。
【００４７】
また、本発明で使用するランダム共重合体型高分子量電荷輸送物質の場合、交互共重合体型やブロック共重合体型のものに比べて、溶剤に対する溶解性や結着樹脂との相溶性などをコントロールしやすいなどの利点がある。
【００４８】
本発明の電子写真感光体の感光層においては、上記式（１）で示される構造を有するランダム共重合体型高分子量電荷輸送物質を１種類だけ用いてもよいし、２種類用いてもよい。
【００４９】
さらに、本発明の効果を損なわない範囲で、低分子量の電荷輸送物質を併用しても構わない。本発明の効果を損なわないという観点からは、上記式（１）で示される構造を有するランダム共重合体型高分子量電荷輸送物質の電荷輸送能を有する構造（繰り返し構造単位）の割合が、全電荷輸送能を有する構造（該繰り返し構造単位と該低分子量電荷輸送物質の和）に対して、５０モル％以上であることが好ましく、さらには７０モル％以上がより好ましい。
【００５０】
次に、本発明の電子写真感光体の構成について説明する。
【００５１】
本発明における電子写真感光体は、感光層が電荷輸送物質と電荷発生物質を同一の層に含有する単層型であっても、電荷輸送物質を含有する電荷輸送層と電荷発生物質を含有する電荷発生層に分離した積層型でもよいが、電子写真特性的には積層型が好ましい。また、積層型には、支持体側から電荷発生層、電荷輸送層の順に積層した順層型と、支持体側から電荷輸送層、電荷発生層の順に積層した逆層型があるが、電子写真特性的には順層型がより好ましい。
【００５２】
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、ステンレスなどの金属、あるいは導電層を設けた金属、紙、プラスチックなどが挙げられ、形状はシート状、円筒状などがあげられる。
【００５３】
レーザービームプリンターなど、画像露光にレーザー光を用いる場合は、散乱による干渉縞防止、または、支持体の傷を被覆することを目的とした導電層を設けてもよい。導電層は、カーボンブラック、金属粒子などの導電性粉体を、結着樹脂に分散させて形成することができる。導電層の膜厚は５〜４０μｍが好ましく、１０〜３０μｍがより好ましい。
【００５４】
支持体または導電層上と感光層との間には、接着機能を有する中間層を設けてもよい。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、ポリエーテルウレタンなどが挙げられる。これらは適当な溶剤に溶解して塗布される。中間層の膜厚は０．０５〜５μｍが好ましく、０．３〜１μｍがより好ましい。
【００５５】
支持体、導電層または中間層の上には、感光層が設けられる。
【００５６】
以下、電荷輸送物質を含有する電荷輸送層と電荷発生物質を含有する電荷発生層に分離した積層型感光層について説明する。
【００５７】
電荷発生層に使用する電荷発生物質としては、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、非対称キノシアニン系の各顔料が挙げられる。
【００５８】
電荷発生層は、上記電荷発生物質を０．３〜４倍量の結着樹脂および溶剤と共に、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、ロールミルおよび液衝突型高速分散機などの方法でよく分散し、分散液を塗布、乾燥させて形成される。
【００５９】
電荷発生層の膜厚は、５μｍ以下が好ましく、さらには０．１〜２μｍがより好ましい。
【００６０】
電荷輸送層は主として本発明からなる結着樹脂と電荷輸送物質とを溶剤中に溶解させた塗料を塗工乾燥して形成する。電荷輸送物質は０．５〜３倍量の結着樹脂と組み合わされ塗工、乾燥し電荷輸送層を形成する。
【００６１】
電荷輸送層の膜厚は５〜４０μｍが好ましく、さらには１５〜３０μｍが好ましい。
【００６２】
電気絶縁性の結着樹脂は、電子写真感光体として用いることができるものであれば特に限定はしないが、ポリカーボネート樹脂、ポリアリレート樹脂が、本発明の効果を発現するために特に良好である。
【００６３】
ポリカーボネート樹脂およびポリアリレート樹脂の合成法に特に限定はないが、いずれも定法によって得ること容易であり、ポリカーボネートはビスフェノールおよびホスゲンを用いた重縮合、ポリアリレートは、ビスフェノールとジカルボン酸クロライドを用いた重縮合によって得られたものが、残留物などの純度面から電子写真特性（感度など）として、また、分子量、分子量分布などの面から機械特性（強度など）として好ましい。
【００６４】
電荷輸送物質は、０．５〜１０倍量の結着樹脂と組み合わされ、塗工、乾燥を経て電荷輸送層を形成するが、本発明の特徴を引き出すためには、結着樹脂の量を電荷輸送物質に対して１〜８倍量さらに好ましくは２〜４倍量とすることが良い（質量比）。
【００６５】
電荷輸送層の膜厚は５〜４０μｍであることが好ましく、さらには１０〜３５μｍであることがより好ましい。
【００６６】
本発明の高分子量電荷輸送物質は、既存の低分子量電荷輸送物質と併用してもよく、併用してもよい電荷輸送物質としては、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、チアゾール系化合物などが挙げられる。
【００６７】
感光層が単層型の場合は、上述のような電荷発生物質や電荷輸送物質を、結着樹脂に分散し、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。
【００６８】
単層型の感光層の膜厚は５〜４０μｍであることが好ましく、さらには１５〜３０μｍであることがより好ましい。
【００６９】
また、感光層の上に、感光層を保護することを目的として保護層を設けることもできる。
【００７０】
さらに必要に応じて、電子写真感光体の表面層に、潤滑性を持たせるための滑材や強度を増すためのフィラーなどを添加することもできる。
【００７１】
図１に本発明の電子写真感光体を有する電子写真装置の概略構成を示す。
【００７２】
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。
【００７３】
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。
【００７４】
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。
【００７５】
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、さらに、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、繰り返し像形成に使用される。なお、図のように、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。
【００７６】
本発明においては、上述の電子写真感光体１、帯電手段３、現像手段５およ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、帯電手段３、現像手段５およびクリーニング手段９の少なくとも１つを感光体１ととも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。
【００７７】
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、この信号にしたがって行われるレーザービームの走査、ＬＥＤアレイの駆動およ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。
【００７８】
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、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。
【００７９】
なお、本発明の効果は、電子写真プロセススピード（上述の、電子写真感光体を帯電し、露光による潜像形成、トナーによる現像、紙などへの転写後に、感光体表面をクリーニングするというプロセスの稼動速度。）が速い系（１３５ｍｍ／ｓ以上）や、クリーニング手段にクリーニングブレードを用いた系において顕著に現れる。
【００８０】
また、重量平均分子量（Ｍｗ）は、ゲルパーミエーションクロマトグラフィー装置ＨＬＣ８１２０ＧＰＣ（東ソー（株））を用い、標準ポリスチレン換算で示される値で示した。
【００８１】
【実施例】
以下、実施例にしたがって、本発明をより一層詳細に説明する。
【００８２】
（合成例１）
Ｎ，Ｎ’−ジ（１，４−ジメチルフェニル）ベンジジン３．９２ｇとＮ，Ｎ’−ジ（３−トリフルオロメチルフェニル）ベンジジン４．７２ｇおよび２，７−ジヨードビフェニル８．１２ｇを、ｏ−ジクロロベンゼン１０ｍｌに溶解し、銅粉６．４ｇと炭酸カリウム５．５ｇを加えて、８時間加熱還流を行った。
【００８３】
放冷後、触媒を除き、アセントンに注ぎ黄色の固体を得た。
【００８４】
さらに、得られた固体を再びトルエンに溶解し、活性炭処理、カラムクロマト、再沈殿により精製を行い、淡黄色固体６．５ｇを得た。
【００８５】
この淡黄色固体は上記（ＣＴＰ−１）の構造であり、（ＣＴ−２）の（ＣＴ−２１）に対するモル比の値は５０／５０であった。
【００８６】
その他のランダム共重合体型高分子量電荷輸送物質も、合成例１と同様の方法で合成することができる。
【００８７】
以下、「部」は「質量部」を意味する。
【００８８】
（実施例１）
直径３０ｍｍ、長さ３５７．５ｍｍのアルミニウムシリンダーを支持体とし、それに、以下の材料より構成される塗料を支持体上に浸漬法で塗布し、１４０℃、３０分熱硬化して、膜厚１５μｍの導電層を形成した。
【００８９】
導電性顔料：ＳｎＯ_２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
結着樹脂：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＝２／８　２０部
この導電層の上に、Ｎ−メトキシメチル化ナイロン３部および共重合ナイロン３部をメタノール６５部、ｎ−ブタノール３０部の混合溶媒に溶解した溶液を浸漬法で塗布し、膜厚０．６μｍの中間層を形成した。
【００９０】
次に、ＣｕＫαのＸ線回折スペクトルにおける回折角２θ±０．２°の７．３°、２８．１°に強いピークを有するヒドロキシガリウムフタロシアニン４部とポリビニルブチラール（商品名：エスレックＢＸ−１、積水化学製）２部およびシクロヘキサノン６０部を、直径１ｍｍのガラスビーズを用いたサンドミル装置で４時間分散し、次に、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。
【００９１】
この分散液を、浸漬法で中間層の上に塗布し、膜厚０．３μｍの電荷発生層を形成した。
【００９２】
次に、上記合成例１で得られた（ＣＴＰ−１）４部とポリカーボネート樹脂（ユーピロンＺ−４００：三菱エンジニアリング（株）製）１０部をモノクロロベンゼン８０部とジクロロメタン２０部の混合溶媒に溶解させ、電荷輸送層用塗料を調製した。
【００９３】
この塗料を、浸漬法で電荷発生層の上に塗布し、１２０℃で１時間乾燥し、膜厚２５μｍの電荷輸送層を形成し、電子写真感光体を得た。
【００９４】
以下、作製した電子写真感光体の評価について説明する。
【００９５】
評価に用いた装置は、キヤノン（株）製ＬＢＰ−９５０（プロセススピード１４４．５ｍｍ／ｓ）の改造機である。
【００９６】
改造は、帯電の制御を定電流制御から定電圧制御に変更し、さらにピーク間電圧を３０％アップした。
【００９７】
作製した電子写真感光体を、この改造機で、高温高湿（Ｈ／Ｈ：２８℃、９０％ＲＨ）下で通紙耐久試験を行った。
【００９８】
シーケンスはプリント１枚ごとに１回停止する間欠モードとした。
【００９９】
トナーがなくなったならば補給し、画像で問題がでるまで耐久した。
【０１００】
また、研磨テープを用いたテーバー摩耗試験機を用いて電子写真感光体の表面を１８分摩耗させ、そのときの質量減少分（テーバー減少量）を測定した。
【０１０１】
さらに、電子写真感光体の一部に、１５分間、３０００ｌｕｘの白色蛍光灯の光を照射し、５分間放置後の明部電位を測定し、光を照射する前から明部電位がどれだけ下がったかを測定して、それをフォトメモリー値とした。
【０１０２】
さらに、ソルベントクラック性は、電子写真感光体表面に指脂を付着させて８０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観察した。
【０１０３】
評価結果を表３に示す。
【０１０４】
（実施例２〜２０）
実施例１において、電荷輸送層に使用したランダム共重合体型高分子量電荷輸送物質を表２に示す構造・構成比・重量平均分子量のものに変更した以外は、実施例１と同様に電子写真感光体を作製し、評価した。
【０１０５】
評価結果を表３に示す。
【０１０６】
【表２】

【０１０７】
【表３】

【０１０８】
（比較例１）
実施例１において、電荷輸送層に使用したランダム共重合体型高分子量電荷輸送物質を、下記式で示される構造を有する化合物に変更した以外は、実施例１と同様に電子写真感光体を作製し、評価した。
【０１０９】
【外１２】

【０１１０】
（比較例２）
実施例１において、電荷輸送層に使用したランダム共重合体型高分子量電荷輸送物質を、下記式で示される繰り返し構造単位を有する単独重合体（重量平均分子量（Ｍｗ）：４０００）に変更した以外は、実施例１と同様に電子写真感光体を作製し、評価した。
【０１１１】
【外１３】

【０１１２】
（比較例３）
実施例１において、電荷輸送層に使用したランダム共重合体型高分子量電荷輸送物質を、下記式で示される繰り返し構造単位を有する単独重合体（重量平均分子量（Ｍｗ）：３２００）に変更した以外は、実施例１と同様に電子写真感光体を作製し、評価した。
【０１１３】
【外１４】

【０１１４】
（比較例４）
実施例１において、電荷輸送層に使用したランダム共重合体型高分子量電荷輸送物質を、下記式で示される繰り返し構造単位を有する交互共重合体（重量平均分子量（Ｍｗ）：３５００）に変更した以外は、実施例１と同様に電子写真感光体を作製し、評価した。
【０１１５】
【外１５】

【０１１６】
（比較例５）
実施例２において、電荷輸送層に使用したランダム共重合体型高分子量電荷輸送物質を、同じ組成比で別途ブロック共重合させたブロック共重合体（重量平均分子量（Ｍｗ）：４１００）に変更した以外は、実施例２と同様に電子写真感光体を作製し、評価した。
【０１１７】
比較例１〜５の評価結果を表４に示す。
【０１１８】
【表４】

【０１１９】
（比較例６〜８）
実施例１〜３において、それぞれ、電荷輸送層に使用したランダム共重合体型高分子量電荷輸送物質の重量平均分子量を表５に示すように変更した以外は、それぞれ、実施例１〜３と同様に電子写真感光体を作製し、評価した。
【０１２０】
評価結果を表６に示す。
【０１２１】
【表５】

【０１２２】
【表６】

【０１２３】
（実施例２１〜２４）
実施例１、２において、電荷輸送層に使用した結着樹脂を表７に示すように変更した以外は、それぞれ、実施例１、２と同様に電子写真感光体を作製し、評価した。
【０１２４】
評価結果を表８に示す。
【０１２５】
【表７】

【０１２６】
なお、結着樹脂（Ｂ−１）とは、下記式（Ｂ−１）で示される繰り返し構造単位を有する単独重合体である。
【外１６】

【０１２７】
また、結着樹脂（Ｂ−２）とは、下記式（Ｂ−２−１）で示される繰り返し構造単位と下記式（Ｂ−２−２）で示される繰り返し構造単位とを有する共重合体である。
【０１２８】
【外１７】

【０１２９】
【表８】

【０１３０】
【発明の効果】
本発明によれば、耐摩耗性および耐キズ性の機械的強度が強く、かつ、優れた耐ソルベントクラック性を有し、かつ、接触帯電による放電に対する耐電気特性が良好であり、フォトメモリーの少ない電子写真感光体を提供することができる。
【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電子写真装置の概略構成の例を示す図である。
【符号の説明】
１　電子写真感光体
２　軸
３　帯電手段
４　露光光
５　現像手段
６　転写手段
７　転写材
８　像定着手段
９　クリーニング手段
１０　前露光光
１１　プロセスカートリッジ
１２　レール[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an inorganic electrophotographic photosensitive member having a photosensitive layer mainly containing an inorganic photoconductive compound such as selenium, zinc oxide, and cadmium sulfide has been widely used as an electrophotographic photosensitive member.
[0003]
However, inorganic electrophotographic photoreceptors have problems such as thermal stability, moisture resistance, durability, productivity, and safety.
[0004]
In recent years, for the purpose of overcoming the drawbacks of inorganic electrophotographic photosensitive members, organic electrophotographic photosensitive members containing various organic photoconductive compounds as main components have been actively developed.
[0005]
In order to satisfy both electrical and mechanical properties, organic electrophotographic photoreceptors are sometimes used as stacked (separated function) electrophotographic photoreceptors in which a charge transport layer and a charge generation layer are laminated. Many.
[0006]
As a matter of course, the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and even optical characteristics according to the applied electrophotographic process.
[0007]
In particular, electrophotographic photoreceptors that are used repeatedly are durable against electrical or mechanical external forces such as corona charging or contact charging, image exposure, toner development, image transfer, and surface cleaning. Is also required.
[0008]
Means for improving the abrasion resistance of the organic electrophotographic photoreceptor include a method of increasing the molecular weight of the binder resin, a method of adding a filler to the binder, or a siloxane structure or a fluorine-containing substitution in the structure of the binder resin. By introducing a structure for imparting lubricity such as a base or adding a solid lubricant such as polytetrafluoroethylene (PTFE), the coefficient of friction with cleaning means such as a cleaning blade is reduced. Methods are known.
[0009]
Further, the use of various binder resins having excellent mechanical strength has also been proposed.However, even if the binder resin itself has excellent mechanical strength, a binder is used because a low-molecular-weight charge transport material is mixed and used. The film strength inherent in the resin coating cannot be fully utilized, and sufficient durability in abrasion resistance and scratch resistance has not always been obtained. On the other hand, if the amount of the added charge transport material is reduced in order to utilize the original film strength of the binder resin, a problem arises in that the electrophotographic sensitivity is reduced and the residual potential is increased. And electrophotographic properties have not yet been achieved.
[0010]
Also, a method of imparting lubricity to the photosensitive layer and reducing the coefficient of friction with cleaning means such as a cleaning blade also causes a decrease in the film strength of the photosensitive layer, and sufficient durability can be obtained. Absent.
[0011]
On the other hand, for the purpose of improving the decrease in film strength due to the addition of a low molecular weight charge transporting substance, use of a high molecular weight charge transporting substance has been disclosed in JP-A-64-9964, JP-A-2-282263, and JP-A-3-221522. And Japanese Patent Application Laid-Open No. 8-208820, however, many of them do not always have sufficient abrasion resistance, and even if they have a certain film strength, the production cost is very high. And it is not suitable for practical use.
[0012]
[Problems to be solved by the invention]
An object of the present invention is to solve the above problems and provide an electrophotographic photoreceptor having high mechanical strength of wear resistance and scratch resistance and excellent in repetition stability.
[0013]
Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having such an electrophotographic photosensitive member.
[0014]
[Means for Solving the Problems]
The present invention provides an electrophotographic photoreceptor having a photosensitive layer on a support, wherein the surface layer of the photosensitive layer is
An electrically insulating binder resin,
An electrophotographic photoreceptor comprising a random copolymer type high molecular weight charge transport material having a structure represented by the following formula (1).
[0015]
[Outside 3]

[0016]
(In the formula (1), Ar ¹¹ , Ar ¹² , and Ar ¹³ have the same structure, and represent a substituted or unsubstituted divalent aromatic hydrocarbon ring group other than a phenyl group. Ar ¹⁴ , Ar ¹⁵ , Ar ¹⁶ independently represents a substituted or unsubstituted aromatic hydrocarbon ring group or a substituted or unsubstituted aromatic heterocyclic group, provided that at least one of Ar ¹⁴ and Ar ¹⁵ is an electron-withdrawing group K, m, and n mean a copolymerization ratio, k and m are integers of 1 or more, and n is an integer of 0 or more.)
[0017]
Further, the present invention is a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0019]
In the present invention, for the sake of convenience, the structure of the high molecular weight charge transporting substance to be contained in the photosensitive layer of the electrophotographic photoreceptor may be such that the number of repeating structural units having Ar ¹¹ and Ar ¹² is k, and the repeating structure having Ar ¹² and Ar ¹⁵ is The number of units is m, and the number of repeating structural units having Ar ¹³ and Ar ¹⁶ is n, which is represented by the above formula (1).
[0020]
However, the high molecular weight charge transporting material used in the present invention is not limited to binary copolymers and terpolymers, and the fourth or higher repetition rate may be used as long as the effects of the present invention are not impaired. Structural units may be introduced. That is, there may be a plurality of repeating structural units having Ar ¹³ and Ar ¹⁶ in the above formula (1). From the viewpoint of not impairing the effects of the present invention, the sum (k + m) of the number (k) of the repeating structural units having Ar ¹¹ and Ar ¹² and the number (m) of the repeating structural units having Ar ¹² and Ar ¹⁵ is obtained. The ratio value ((k + m) / sum) to the total number (sum) of the repeating structural units of the high molecular weight charge transporting material is preferably from 50/100 to 100/100, and more preferably from 75/100 to 100/100.
[0021]
The above formula (1) is a structural formula as if the high molecular weight charge transporting material is limited to a block copolymer, but the high molecular weight charge transporting substance contained in the photosensitive layer of the electrophotographic photoreceptor of the present invention. The structure of the transport substance is a random copolymer in which each repeating structural unit is present at random, and k, m, and n only mean the copolymerization ratio (where k and m are 1 or more. And n is an integer of 0 or more.)
[0022]
With the random copolymer in the present invention, without performing an operation to cause a polymerization reaction having a regularity such as an alternating copolymer or a block copolymer intentionally, as shown in the synthesis examples described below Means a copolymer obtained by simultaneously charging two or more types of monomer (monomer) raw materials into a reaction vessel during a copolymer synthesis reaction and reacting them (usually synthesized by such a synthesis method). The polymer thus obtained is considered to be a random copolymer.) The term "random copolymer type high molecular weight charge transporting material" means a high molecular weight charge transporting material synthesized by the above method for synthesizing a random copolymer.
[0023]
The structures of the various copolymers are as follows.
[0024]
When the repeating structural units are A and B, random copolymers are those randomly arranged such as AAABAA, ABABBA, AABBABA, and alternate copolymers are regularly arranged alternately with ABABAB. The block copolymer is a copolymer in which the length of each repeating structural unit such as AAABBBB and AAAAABBBB varies, but each repeating structural unit exists as a block.
[0025]
Ar ¹¹ , Ar ¹² and Ar ¹³ in the above formula (1) are preferably a divalent group having a structure represented by the following formula (21).
[Outside 4]

[0026]
Examples of the aromatic hydrocarbon ring group include a monovalent group obtained by removing one hydrogen atom from naphthalene, anthracene, perylene, fluorene, biphenyl, terphenyl, and the like. Examples of the aromatic heterocyclic group include carbazole, Monovalent groups in which one hydrogen atom has been removed from furan, benzofuran, thiophene, benzothiophene, quinoline, phenazine, dibenzothiophene, dibenzofuran, carbazole, and the like can be given.
[0027]
Examples of the divalent aromatic hydrocarbon ring group include a divalent group obtained by removing two hydrogen atoms from naphthalene, anthracene, perylene, fluorene, biphenyl, terphenyl, and the like. Examples of the heterocyclic group include a divalent group obtained by removing two hydrogen atoms from carbazole, furan, benzofuran, thiophene, benzothiophene, quinoline, phenazine, dibenzothiophene, dibenzofuran, carbazole, and the like.
[0028]
Examples of the alkyl group include a methyl group and an ethyl group.
[0029]
Examples of the substituent which each group may have include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an alkoxy group such as a methoxy group, an ethoxy group and a propoxy group, a phenoxy group and Examples include an aryloxy group such as a naphthoxy group, a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, and a disubstituted amino group such as a dimethylamino group, a diethylamino group and a diphenylamino group.
[0030]
In the random copolymer type high molecular weight charge transporting material having the structure represented by the above formula (1), the number of side chains having no electron withdrawing group (B) and the number of side chains having electron withdrawing group (A) ) Is preferably 2 or more and 40 or less.
[0031]
N in the above formula (1) is preferably 0, that is, the random copolymer type high molecular weight charge transporting material having the structure represented by the above formula (1) is preferably a binary copolymer.
[0032]
The value of the ratio of k to m (k / m) is more preferably 1 or more and 30 or less.
[0033]
The weight average molecular weight (Mw) of the random copolymer type high molecular weight charge transporting material having the structure represented by the above formula (1) is preferably 1500 or more, more preferably 9000 or less. On the other hand, it is preferably 5000 or less, more preferably 3000 or less.
[0034]
Examples of the repeating structural unit constituting the random copolymer type high molecular weight charge transporting substance used in the present invention are shown below, but the present invention is not limited thereto.
[0035]
[Outside 5]

[0036]
[Outside 6]

[0037]
[Outside 7]

[0038]
[Outside 8]

[0039]
[Outside 9]

[0040]
[Outside 10]

[0041]
[Outside 11]

[0042]
Next, examples of the structure of the random copolymer type high molecular weight charge transporting material used in the present invention are shown below, but the present invention is not limited thereto.
[0043]
[Table 1]

[0044]
Among these, CTP-3, 6, 9, 12, and 13 are preferable, and CTP-3 and 12 are more preferable.
[0045]
Since the charge transporting substance contained in the surface layer of the photosensitive layer of the electrophotographic photoreceptor of the present invention has a high molecular weight, a decrease in film strength due to the addition of the charge transporting substance is small, and it is excellent in scratch resistance and abrasion resistance.
[0046]
Further, a copolymer having two or more kinds of repeating structural units and having a repeating structural unit having an electron-withdrawing group is a homopolymer having a single repeating structural unit or having an electron-withdrawing group. Compared to a polymer without a repeating structural unit, the ionization potential of the charge-transporting substance is reduced less and is resistant to oxidation due to discharge. .
[0047]
Further, in the case of the random copolymer type high molecular weight charge transporting material used in the present invention, the solubility in a solvent and the compatibility with a binder resin are controlled as compared with those of the alternating copolymer type or the block copolymer type. There are advantages such as ease.
[0048]
In the photosensitive layer of the electrophotographic photoreceptor of the present invention, only one kind or two kinds of the random copolymer type high molecular weight charge transport material having the structure represented by the above formula (1) may be used.
[0049]
Further, as long as the effects of the present invention are not impaired, a low-molecular-weight charge transport material may be used in combination. From the viewpoint that the effect of the present invention is not impaired, the ratio of the structure (repeating structural unit) having the charge transporting ability of the random copolymer type high molecular weight charge transporting material having the structure represented by the above formula (1) is determined by the total charge It is preferably at least 50 mol%, more preferably at least 70 mol%, based on the structure having a transporting ability (sum of the repeating structural unit and the low-molecular-weight charge transporting substance).
[0050]
Next, the configuration of the electrophotographic photosensitive member of the present invention will be described.
[0051]
The electrophotographic photoreceptor in the present invention contains a charge transport layer containing a charge transport material and a charge generation material, even if the photosensitive layer is a single layer containing a charge transport material and a charge generation material in the same layer. Although a laminated type separated into a charge generation layer may be used, a laminated type is preferable in terms of electrophotographic characteristics. The stacked type includes a normal layer type in which a charge generation layer and a charge transport layer are stacked in this order from the support side, and an inverted layer type in which a charge transport layer and a charge generation layer are stacked in order from the support side. Specifically, a normal layer type is more preferable.
[0052]
The support has only to be conductive, and may be a metal such as aluminum or stainless steel, or a metal provided with a conductive layer, paper, plastic, or the like. The shape may be a sheet, a cylinder, or the like.
[0053]
When laser light is used for image exposure such as a laser beam printer, a conductive layer may be provided for the purpose of preventing interference fringes due to scattering or covering a scratch on a support. The conductive layer can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably from 5 to 40 μm, more preferably from 10 to 30 μm.
[0054]
An intermediate layer having an adhesive function may be provided between the support or the conductive layer and the photosensitive layer. Examples of the material of the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are applied by dissolving in an appropriate solvent. The thickness of the intermediate layer is preferably from 0.05 to 5 μm, more preferably from 0.3 to 1 μm.
[0055]
A photosensitive layer is provided on the support, the conductive layer or the intermediate layer.
[0056]
Hereinafter, the laminated photosensitive layer separated into a charge transporting layer containing a charge transporting substance and a charge generating layer containing a charge generating substance will be described.
[0057]
Examples of the charge generating material used in the charge generating layer include selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanine, anthantrone, dibenzopyrene quinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments. Is mentioned.
[0058]
The charge generation layer is formed by mixing the above charge generation substance with a binder resin and a solvent in an amount of 0.3 to 4 times as much as a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an attritor, a roll mill, and a liquid collision type high-speed disperser. And the dispersion is applied and dried.
[0059]
The thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 to 2 μm.
[0060]
The charge transport layer is mainly formed by applying and drying a coating material in which the binder resin of the present invention and the charge transport material are dissolved in a solvent. The charge transporting material is combined with 0.5 to 3 times the amount of the binder resin, applied and dried to form a charge transporting layer.
[0061]
The thickness of the charge transport layer is preferably 5 to 40 μm, more preferably 15 to 30 μm.
[0062]
The electrically insulating binder resin is not particularly limited as long as it can be used as an electrophotographic photoreceptor, but polycarbonate resins and polyarylate resins are particularly preferable for exhibiting the effects of the present invention.
[0063]
The method for synthesizing the polycarbonate resin and the polyarylate resin is not particularly limited, but both are easy to obtain by a conventional method.Polycarbonate is a polycondensation using bisphenol and phosgene, and polyarylate is a polycondensation using bisphenol and dicarboxylic acid chloride. Those obtained by condensation are preferred as electrophotographic properties (sensitivity, etc.) in terms of purity of residues and the like, and mechanical properties (strength, etc.) in terms of molecular weight and molecular weight distribution.
[0064]
The charge transport material is combined with a binder resin in an amount of 0.5 to 10 times, and forms a charge transport layer through coating and drying. In order to bring out the features of the present invention, the amount of the binder resin is reduced. The amount is preferably 1 to 8 times, more preferably 2 to 4 times the mass of the charge transport material (mass ratio).
[0065]
The thickness of the charge transport layer is preferably from 5 to 40 μm, more preferably from 10 to 35 μm.
[0066]
The high molecular weight charge transporting material of the present invention may be used in combination with an existing low molecular weight charge transporting material. Examples of the charge transporting material that may be used in combination include a triarylamine compound, a hydrazone compound, a stilbene compound, and a pyrazoline compound. Oxazole compounds, triallylmethane compounds, thiazole compounds and the like.
[0067]
When the photosensitive layer is a single-layer type, the photosensitive layer can be formed by dispersing the above-described charge generating substance or charge transporting substance in a binder resin, applying a dissolved solution, and drying.
[0068]
The single-layer type photosensitive layer preferably has a thickness of 5 to 40 μm, and more preferably 15 to 30 μm.
[0069]
Further, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer.
[0070]
Further, if necessary, a lubricant for imparting lubricity and a filler for increasing strength can be added to the surface layer of the electrophotographic photosensitive member.
[0071]
FIG. 1 shows a schematic configuration of an electrophotographic apparatus having the electrophotographic photosensitive member of the present invention.
[0072]
In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around an axis 2 in a direction of an arrow at a predetermined peripheral speed. The photoreceptor 1 receives a uniform charge of a predetermined positive or negative potential on its peripheral surface by the (primary) charging means 3 during the rotation process, and then receives light from exposure means (not shown) such as slit exposure or laser beam scanning exposure. Receiving the exposure light 4. Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photoconductor 1.
[0073]
The formed electrostatic latent image is then subjected to toner development 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 paper feeding unit (not shown). The transfer means 6 sequentially transfers the paper to the transfer material 7 taken out and fed in synchronization with the transfer.
[0074]
The transfer material 7 that has undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing, thereby being printed out of the apparatus as a copy.
[0075]
The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the untransferred toner by a cleaning unit 9, and further subjected to a static elimination process by a pre-exposure light 10 from a pre-exposure unit (not shown). Used repeatedly for image formation. As shown in the figure, when the charging means 3 is a contact charging means using a charging roller or the like, the pre-exposure is not necessarily required.
[0076]
In the present invention, a plurality of components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, and the cleaning unit 9 are integrally connected as a process cartridge. It may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, a process in which at least one of the charging means 3, the developing means 5 and the cleaning means 9 is integrally supported together with the photoreceptor 1 to form a cartridge, and which can be attached to and detached from the apparatus main body using a guide means such as a rail 12 of the apparatus main body. The cartridge 11 can be used.
[0077]
When the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 is reflected light or transmitted light from the original, or the original is read by a sensor and converted into a signal. Light emitted by scanning, driving of an LED array, driving of a liquid crystal shutter array, and the like.
[0078]
The electrophotographic photoreceptor of the present invention can be widely used not only for electrophotographic copying machines but also for electrophotographic applications such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.
[0079]
The effect of the present invention is an electrophotographic process speed (the above-described process of charging the electrophotographic photosensitive member, forming a latent image by exposure, developing with toner, and transferring the photosensitive member surface to paper, and then cleaning the photosensitive member surface). This is noticeable in a system with a high operating speed (135 mm / s or more) or a system using a cleaning blade as a cleaning means.
[0080]
The weight average molecular weight (Mw) was indicated by a value expressed in terms of standard polystyrene using a gel permeation chromatography apparatus HLC8120GPC (Tosoh Corporation).
[0081]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples.
[0082]
(Synthesis example 1)
3.92 g of N, N′-di (1,4-dimethylphenyl) benzidine, 4.72 g of N, N′-di (3-trifluoromethylphenyl) benzidine and 8.12 g of 2,7-diiodobiphenyl, The resultant was dissolved in 10 ml of o-dichlorobenzene, 6.4 g of copper powder and 5.5 g of potassium carbonate were added, and the mixture was heated under reflux for 8 hours.
[0083]
After cooling, the catalyst was removed, and the mixture was poured into Astonton to obtain a yellow solid.
[0084]
Further, the obtained solid was dissolved again in toluene and purified by activated carbon treatment, column chromatography, and reprecipitation to obtain 6.5 g of a pale yellow solid.
[0085]
This pale yellow solid had the structure of (CTP-1), and the molar ratio of (CT-2) to (CT-21) was 50/50.
[0086]
Other random copolymer type high molecular weight charge transport materials can be synthesized in the same manner as in Synthesis Example 1.
[0087]
Hereinafter, “parts” means “parts by mass”.
[0088]
(Example 1)
An aluminum cylinder having a diameter of 30 mm and a length of 357.5 mm was used as a support, and a coating composed of the following materials was applied on the support by a dipping method, and was heat-cured at 140 ° C. for 30 minutes to form a film having a thickness of 15 μm. Was formed.
[0089]
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 parts Solvent: methanol / methoxypropanol = 2/8 20 parts On this conductive layer, a solution prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol was applied by an immersion method. Was formed.
[0090]
Next, 4 parts of hydroxygallium phthalocyanine having strong peaks at 7.3 ° and 28.1 ° at diffraction angles 2θ ± 0.2 ° in the X-ray diffraction spectrum of CuKα and polyvinyl butyral (trade name: Eslek BX-1, 2 parts of Sekisui Chemical Co., Ltd. and 60 parts of cyclohexanone were dispersed in a sand mill using glass beads having a diameter of 1 mm for 4 hours, and then 100 parts of ethyl acetate was added to prepare a dispersion for a charge generation layer.
[0091]
This dispersion was applied on the intermediate layer by a dipping method to form a 0.3 μm-thick charge generation layer.
[0092]
Next, 4 parts of (CTP-1) obtained in Synthesis Example 1 and 10 parts of a polycarbonate resin (Iupilon Z-400: manufactured by Mitsubishi Engineering Co., Ltd.) are dissolved in a mixed solvent of 80 parts of monochlorobenzene and 20 parts of dichloromethane. Then, a paint for a charge transport layer was prepared.
[0093]
This paint was applied on the charge generation layer by an immersion method, and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 25 μm, thereby obtaining an electrophotographic photosensitive member.
[0094]
Hereinafter, evaluation of the produced electrophotographic photosensitive member will be described.
[0095]
The device used for the evaluation is a modified machine of LBP-950 (process speed 144.5 mm / s) manufactured by Canon Inc.
[0096]
The modification changed the control of charging from constant current control to constant voltage control, and further increased the peak-to-peak voltage by 30%.
[0097]
The manufactured electrophotographic photoreceptor was subjected to a paper-passing durability test under high temperature and high humidity (H / H: 28 ° C., 90% RH) with this modified machine.
[0098]
The sequence was an intermittent mode in which the printing was stopped once for each print.
[0099]
When the toner ran out, it was replenished and endured until a problem appeared on the image.
[0100]
Further, the surface of the electrophotographic photosensitive member was abraded for 18 minutes using a Taber abrasion tester using a polishing tape, and the mass reduction (Taber reduction) at that time was measured.
[0101]
Further, a part of the electrophotographic photoreceptor is irradiated with light of a 3000 lux white fluorescent lamp for 15 minutes, and the bright portion potential after being left for 5 minutes is measured. Was measured and used as a photo memory value.
[0102]
Further, the solvent cracking property was determined by adhering finger grease to the surface of the electrophotographic photosensitive member and leaving it to stand for 80 hours, and observing the presence or absence of solvent cracking by microscopic observation.
[0103]
Table 3 shows the evaluation results.
[0104]
(Examples 2 to 20)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the random copolymer type high molecular weight charge transporting material used in the charge transporting layer was changed to the structure, composition ratio, and weight average molecular weight shown in Table 2. The body was made and evaluated.
[0105]
Table 3 shows the evaluation results.
[0106]
[Table 2]

[0107]
[Table 3]

[0108]
(Comparative Example 1)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the random copolymer type high molecular weight charge transport material used in the charge transport layer was changed to a compound having a structure represented by the following formula. ,evaluated.
[0109]
[Outside 12]

[0110]
(Comparative Example 2)
In Example 1, except that the random copolymer type high molecular weight charge transporting substance used for the charge transporting layer was changed to a homopolymer having a repeating structural unit represented by the following formula (weight average molecular weight (Mw): 4000). An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1.
[0111]
[Outside 13]

[0112]
(Comparative Example 3)
In Example 1, except that the random copolymer type high molecular weight charge transporting substance used in the charge transporting layer was changed to a homopolymer having a repeating structural unit represented by the following formula (weight average molecular weight (Mw): 3200). An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1.
[0113]
[Outside 14]

[0114]
(Comparative Example 4)
In Example 1, except that the random copolymer type high molecular weight charge transporting substance used for the charge transporting layer was changed to an alternating copolymer having a repeating structural unit represented by the following formula (weight average molecular weight (Mw): 3500) In the same manner as in Example 1, an electrophotographic photosensitive member was prepared and evaluated.
[0115]
[Outside 15]

[0116]
(Comparative Example 5)
In Example 2, except that the random copolymer type high molecular weight charge transporting substance used in the charge transporting layer was changed to a block copolymer (weight average molecular weight (Mw): 4100) separately subjected to block copolymerization at the same composition ratio. Prepared and evaluated an electrophotographic photosensitive member in the same manner as in Example 2.
[0117]
Table 4 shows the evaluation results of Comparative Examples 1 to 5.
[0118]
[Table 4]

[0119]
(Comparative Examples 6 to 8)
In Examples 1 to 3, except that the weight average molecular weight of the random copolymer type high molecular weight charge transporting substance used for the charge transporting layer was changed as shown in Table 5, respectively, the same as Examples 1 to 3, respectively. An electrophotographic photosensitive member was prepared and evaluated.
[0120]
Table 6 shows the evaluation results.
[0121]
[Table 5]

[0122]
[Table 6]

[0123]
(Examples 21 to 24)
In Examples 1 and 2, electrophotographic photoreceptors were prepared and evaluated in the same manner as in Examples 1 and 2, except that the binder resin used for the charge transport layer was changed as shown in Table 7.
[0124]
Table 8 shows the evaluation results.
[0125]
[Table 7]

[0126]
The binder resin (B-1) is a homopolymer having a repeating structural unit represented by the following formula (B-1).
[Outside 16]

[0127]
The binder resin (B-2) is a copolymer having a repeating structural unit represented by the following formula (B-2-1) and a repeating structural unit represented by the following formula (B-2-2). It is.
[0128]
[Outside 17]

[0129]
[Table 8]

[0130]
【The invention's effect】
According to the present invention, the mechanical strength of abrasion resistance and scratch resistance is strong, and it has excellent solvent crack resistance, and has good electrical resistance to discharge due to contact charging, and the photo memory has It is possible to provide a small number of electrophotographic photosensitive members.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus having an electrophotographic photosensitive member of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 electrophotographic photosensitive member 2 shaft 3 charging means 4 exposure light 5 developing means 6 transfer means 7 transfer material 8 image fixing means 9 cleaning means 10 pre-exposure light 11 process cartridge 12 rail

Claims (9)

In an electrophotographic photosensitive member having a photosensitive layer on a support, the surface layer of the photosensitive layer,
An electrically insulating binder resin,
An electrophotographic photosensitive member comprising: a random copolymer type high molecular weight charge transport material having a structure represented by the following formula (1):
[Outside 1]

(In the formula (1), Ar ¹¹ , Ar ¹² , and Ar ¹³ have the same structure, and represent a substituted or unsubstituted divalent aromatic hydrocarbon ring group other than a phenyl group. Ar ¹⁴ , Ar ¹⁵ , Ar ¹⁶ independently represents a substituted or unsubstituted aromatic hydrocarbon ring group or a substituted or unsubstituted aromatic heterocyclic group, provided that Ar ¹⁴ , Ar ¹⁵ , and Ar ¹⁶ are different from each other; ^At least one of ¹⁴ and Ar ¹⁵ has an electron-withdrawing group, k, m, and n mean a copolymerization ratio, k and m are integers of 1 or more, and n is an integer of 0 or more. .) The electrophotographic photoreceptor according to claim 1, wherein Ar ¹¹ , Ar ¹² and Ar ¹³ in the formula (1) are divalent groups having a structure represented by the following formula (21).
[Outside 2]

In the random copolymer type high molecular weight charge transporting material having the structure represented by the formula (1), the number of side chains having electron-withdrawing groups (B) is the number of side chains having no electron-withdrawing groups (A) 3. The electrophotographic photoreceptor according to claim 1, wherein the ratio (B / A) to the ratio (B) is 2 or more and 40 or less. The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein the weight average molecular weight (Mw) of the random copolymer type high molecular weight charge transporting material having the structure represented by the formula (1) is 1500 or more. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein n in the formula (1) is 0. The electrophotographic photoreceptor according to claim 1, wherein n in the formula (1) is 0, and a value of a ratio of k to m (k / m) is 1 or more and 30 or less. The photosensitive layer has a charge generating layer containing a charge generating substance and a charge transporting layer containing a random copolymer type high molecular weight charge transporting substance having a structure represented by the formula (1). The electrophotographic photoreceptor according to any one of claims 1 to 6, wherein a surface layer is the charge transport layer. An electrophotographic apparatus main body which integrally supports the electrophotographic photosensitive member according to claim 1 and at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit and a cleaning unit. A process cartridge which is detachably attached to the cartridge. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1, a charging unit, an exposing unit, a developing unit, and a transferring unit.

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