JP3880457B2 - Electrophotographic photosensitive member, process cartridge, electrophotographic apparatus, and method of manufacturing electrophotographic photosensitive member - Google Patents

Description

【００３１】
（式中、Ａｒは置換もしくは無置換のアリーレン基を示し、Ｒ₁は水素原子又はメチル基を示す）
【００３２】
また、電荷輸送能、好ましくは正孔輸送能を有しかつ放射線照射及び加熱により重合・架橋可能な樹脂を用いる場合は、それ単独で電荷輸送層を形成、あるいは前述の電荷輸送材料及び電荷輸送能を有さない放射線照射及び加熱により重合・架橋可能な樹脂を適宜混合することが可能である。
【００３３】
電荷輸送能を有しかつ放射線照射及び加熱により重合・架橋可能な樹脂は、例えば上記の不飽和重合性官能基を有する公知の正孔輸送性化合物や、公知の正孔輸送性化合物の一部に上記の不飽和重合性官能基を付加した化合物等であればよい。公知の正孔輸送性化合物の例としては、ヒドラゾン化合物、ピラゾリン化合物、トリフェニルアミン化合物、ベンジジン化合物及びスチルベン化合物等が挙げられるが、正孔輸送性化合物であればいかなる化合物も使用可能である。
【００３４】
更に、本発明において電子写真感光体表面層の硬度を十分に確保するためには、連鎖重合性官能基を有する化合物は同一分子内に２つ以上の連鎖重合性官能基を有する化合物であることが好ましい。
【００３５】
本発明において、単層構成の電子写真感光体の場合には、少なくとも電荷発生材料、電荷輸送材料及び放射線照射及び加熱により重合・架橋可能な化合物を分散又は溶解した溶液を用いて感光層が形成される。この場合においても先の機能分離型電子写真感光体と同様に、電荷輸送能を有しかつ放射線照射及び加熱により重合・架橋可能な化合物の使用が好ましい。
【００３６】
本発明において、表面層が保護層である場合には、保護層が放射線照射及び加熱により形成される層となり、この工程により重合又は架橋し硬化する化合物から構成される。
【００３７】
この場合、下層である感光層の構成は、電荷発生層及び電荷輸送層をこの順に積層した機能分離型電子写真感光体、電荷輸送層及び電荷発生層をこの順に積層した機能分離型電子写真感光体、あるいは単層電子写真感光体のいずれもが可能であるが、先に述べた理由により、電荷発生層及び電荷輸送層をこの順に積層した電子写真感光体構成が好ましい。
【００３８】
この場合、電荷発生層は、前述と同様な方法で形成され、電荷輸送層は、先の電荷輸送材料をスチレン、酢酸ビニル、塩化ビニル、アクリル酸エステル、メタクリル酸エステル、フッ化ビニリデン、トリフルオロエチレン等のビニル化合物の重合体及び共重合体、ポリビニルアルコール、ポリビニルアセタール、ポリカーボネート、ポリエステル、ポリスルホン、ポリフェニレンオキサイド、ポリウレタン、セルロース樹脂、フェノール樹脂、メラミン樹脂、ケイ素樹脂及びエポキシ樹脂等の結着樹脂中に分散あるいは溶解した溶液を用いて形成される。場合によっては、放射線照射及び加熱により重合・架橋可能な化合物を有する化合物の添加も可能である。
【００３９】
保護層は硬化後に電荷輸送能を有している必要があるため、放射線照射及び加熱工程により重合・架橋し保護層を形成する化合物自体が電荷輸送能力を有さない化合物である場合においては、前述の電荷輸送材料や導電性材料の添加により電荷輸送能を確保することが好ましい。この場合、電荷輸送材料は、放射線照射及び加熱により重合・架橋可能な官能基を有しても有さなくてもかまわないが、電荷輸送材料の可塑性による機械的強度の低下を避けるためには、前者が好ましい。
【００４０】
導電性材料としては、酸化チタンや酸化錫等の導電性微粒子が一般的ではあるが、その他として、導電性高分子化合物等の利用も可能である。放射線照射及び加熱工程により重合・架橋し保護層を形成する化合物自体が電荷輸送能を有する場合においては、この限りではない。本発明においては、表面層の膜硬度や種々の電子写真の点からして、後者のような電荷輸送能を有する化合物を使用した表面層が特に好ましい。
【００４１】
本発明において各々溶液を塗布する方法は、例えば、浸漬コーティング法、スプレイコーティング法、カーテンコーティング法及びスピンコーティング法等の公知の塗布方法が可能であるが、効率性／生産性の点からは浸漬コーティング法が好ましい。また、蒸着、プラズマその他の公知の製膜方法も適宜選択できる。
【００４２】
本発明において、感光層及び保護層には各種添加剤を添加することができる。該添加剤とは、酸化防止剤及び紫外線吸収剤等の劣化防止剤やフッ素系樹脂微粒子等の滑材等である。
【００４３】
次に、放射線照射及び加熱について説明する。
【００４４】
本発明における放射線とは、特開２０００−６６４２５号公報において開示したものと同様に、電子線及びγ線等が挙げられ、装置の大きさ、安全性、コスト及び汎用性等の種々の点から電子線が好ましい。電子線照射をする場合、加速器としては、スキャニング型、エレクトロカーテン型、ブロードビーム型、パルス型及びラミナー型等のいずれの形成も使用することができる。
【００４５】
また、電子線照射により電子写真感光体を形成する本発明においても、電子写真感光体の電気特性及び耐久性能を十分に発現させる上で、電子線の加速電圧と吸収線量が非常に重要なファクターであり、加速電圧は３００ＫＶ以下が好ましく、最適には１５０ＫＶ以下、また線量は好ましくは１〜１００Ｍｒａｄの範囲、より好ましくは５０Ｍｒａｄ以下の範囲である。加速電圧が３００ＫＶを超えたり、線量が１００Ｍｒａｄを超えると、電子写真感光体への劣化が起こり易い傾向にあることは該公報において示した通りである。
【００４６】
本発明者らは、鋭意検討を重ねた結果、放射線照射後も数時間以上にわたって、反応活性点であるラジカルが存在し続けることを発見した。これによれば、放射線照射後のラジカルが存在している間にその系の温度を後述する加熱手段により上昇させることによって、より重合・架橋反応を進行させることができ、同じ線量でも、より硬化度の高い膜が形成されることを実証した。更には、この放射線照射後の加熱を利用した重合・架橋反応を利用すると、従来と比べてより少ない線量で十分な硬化性を得ることが判明した。
【００４７】
すなわち従来の方法では余分な放射線エネルギーによって必要以上のラジカルを生成させていたことになるが、本願においては必要最小限のラジカル発生に対して放射線の線量を決定することの優位性を示している。これはとりもなおさず、より電子写真感光体に対して緩やかな条件で放射線照射が行なえること、また装置の簡略化、低エネルギー化、コストダウン等に対する大きな利点である。
【００４８】
反応活性点であるラジカル開始点の生成量は、重合・架橋する層の構成材料の化学構造自体、すなわちこれらの化合物の放射線に対する開始反応効率にも大きく依存するが、ラジカルの生成量を正確に予測したり測定することは困難であるため、現状では最終的な硬化性を評価することにより、最適な構成材料と放射線照射条件を決定する必要がある。なお本願で使用している不飽和重合性官能基を有する化合物の場合は、おおむね２０Ｍｒａｄ以下の線量においても十分な硬化性を得ることが可能であり、材料によってはわずか１Ｍｒａｄの線量においても十分な硬化性が得られることがわかった。
【００４９】
次に、加熱について説明する。本発明における加熱の手段としては、電子写真感光体の外部あるいは内部からのいずれにおいても行うことができる。外部から加温する場合は、電子写真感光体の近傍に各種のヒーター等を設置し直接加熱する方法等が挙げられる。内部から加温する方法においても、内部に各種ヒーターを設置する方法、加熱された流体を通過させる方法等が挙げられる。また、これらの加熱手段はそのいくつかを組み合わせることが可能である。なお電子写真感光体の温度は、同組成の温度測定用電子写真感光体を別途準備し、
（１）該感光体表面にサーモラベルを貼り付ける
（２）該感光体表面にテープ型熱電対温度計を接触させる
（３）該感光体表面近傍に非接触型放射温度計を配置する
等の方法により測定することが可能であるが、温度の信頼性を高めるためには、単独ではなくこれらいくつかの測定データを総合して電子写真感光体の温度とすることが好ましい。
【００５０】
加熱する温度は、電子写真感光体の温度が室温以上になるように設定することが好ましく、特には放射線照射時の温度以上になるように設定することが好ましい。電子線照射は通常２０℃前後の室温雰囲気下で行うのが一般的であるが、電子線照射時にはそのエネルギーを電子写真感光体及び周りの媒体が吸収するために、これらの温度上昇が起こる。その割合は、加速電圧、ビーム電流値、照射時間、線量等の系に加えられるエネルギーと、吸収する側のエネルギーすなわち照射スペースの大きさや材質、雰囲気気体の流れ、装置の冷却システムや電子写真感光体自体の材料構成等の熱収支に依存し、実質的な線量において電子写真感光体自体は一般的には室温から数十℃程度に温度上昇する。
【００５１】
ここで室温以上好ましくは放射線照射時の温度以上に電子写真感光体の温度を設定する理由は、重合反応メカニズムに起因すると考えられる。放射線照射時には、重合・架橋する層内部において、反応活性点がまず生成し、構成材料が分子レベルで動けるすなわち二分子反応できる分子間距離内において重合が進行する。ある程度、重合・架橋が進行すると、オリゴマーあるいはポリマー化した構成材料はもはやその温度においては分子レベルで動くことが出来なくなり、反応は一旦停止すると考えられる。この時点で反応活性点は先に述べたようにある程度の寿命をもって存在することができるために、この段階において系の温度を上げることで、更に分子レベルでの運動を可能とし、更なる重合、架橋反応を進行させることが可能であると考えられる。
【００５２】
加熱時の温度は高いほど重合・架橋反応に有効ではあるが、電子写真感光体を対象とした本発明においては、２５０℃以下であることが好ましい。これを超える温度になると電子写真感光体の材料が劣化し、電子写真特性が悪くなる傾向にある。より好ましくは２００℃以下、更に好ましくは１５０℃以下である。
【００５３】
一方、温度の下限については、前述のように加熱時の電子写真感光体の温度が放射線照射時の電子写真感光体の温度より高いことで重合・架橋反応が促進されるという推定メカニズムに基づくと、放射線照射時の感光体の温度より少なくとも数十℃は高く設定することが必須であり、好ましくは５０℃以上、特に弊害がない限りにおいては出来るだけ設定温度を高くすることが好ましい。
【００５４】
加温する時間はおおよそ数秒から数十分程度であるが、加温時間よりはむしろ設定温度すなわち電子写真感光体の到達温度が硬化性には大きく影響する。実質的に加温時間とは、昇温時間及び到達温度保持時間を含む。昇温時間は加熱手段や電子写真感光体の種類、特には基材の材質によっても大きく異なるが、数秒から数分程度で所定温度近傍までに到達する手段を選択することが好ましく、あまりに昇温に対して長い時間を費やすことは、特性上は問題ないと推測されるが、生産上は好ましくはない。
【００５５】
到達温度保持時間は、過熱防止／到達温度安定化等の観点から、設定温度に到達した後、場合に応じて数秒から数十分程度設けることが好ましい。これらの時間より短時間、すなわち数秒以内で加温処理を完結することに対して特に問題はないが、装置的な制御の問題や負荷が大きくなる等の点で実用的ではない。一方、これらの時間より長い加熱処理を行なうことも可能ではあるが、生産性等の点からあまり好ましくはない。
【００５６】
加温処理を行なう雰囲気は、重合・架橋反応のメカニズムから考えて、酸素による反応活性点の失活を極力避ける意味でも、真空度が１×１０ ^-2 Ｐａ以下の真空中であることが必須であり、更には１×１０^-5Ｐａ以下であることがより好ましい。
【００５７】
放射線照射から加熱処理までの時間は、先のように反応活性点の失活をなるべく避ける目的で短時間に設定するのが好ましく、実質的には放射線照射後に連続して加熱処理を行なうことが好ましいが、装置上の問題から連続処理が困難である場合には、両者の間に数分から数時間程度の放置時間が生じても構わない。ただし、この時間が極短時間である場合においても、少なからず酸素による重合阻害が起こる可能性があるので、雰囲気の酸素濃度には注意すべきである。
【００５８】
なお、これらの失活速度が遅い場合すなわち真空中を経由する場合、また材料の種類によってラジカル失活速度が遅い等の場合においては、数時間という放置期間を経由しても硬化性は変化しておらず、また本発明者らが実際に放射線照射直後及び数時間放置後の重合・架橋層におけるラジカル量を電子スピン共鳴法により測定した結果においてもラジカル数の減少は確認されなかったことから、場合によっては例えば一日以上の長い放置時間を経由することも可能であると考えられる。また、これらの加熱方法はその数種類の手段を組み合わせることも可能である。
【００５９】
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備えた電子写真装置の概略構成を示す。
【００６０】
図１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。電子写真感光体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又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等の露光手段（不図示）から出力される目的の画像情報の時系列電気デジタル画像信号に対応して強度変調された露光光４を受ける。こうして電子写真感光体１の周面に対し、目的の画像情報に対応した静電潜像が順次形成されていく。
【００６１】
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、不図示の給紙部から電子写真感光体１と転写手段６との間に電子写真感光体１の回転と同期して取り出されて給送された転写材７に、電子写真感光体１の表面に形成担持されているトナー画像が転写手段６により順次転写されていく。
【００６２】
トナー画像の転写を受けた転写材７は、電子写真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画像形成物（プリント、コピー）として装置外へプリントアウトされる。
【００６３】
像転写後の電子写真感光体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が帯電ローラー等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。
【００６４】
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等の構成要素のうち、複数のものを容器に納めて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等の電子写真装置本体に対して着脱自在に構成してもよい。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の少なくとも一つを電子写真感光体１と共に一体に支持してカートリッジ化して、装置本体のレール等の案内手段１２を用いて装置本体に着脱自在なプロセスカートリッジ１１とすることができる。
【００６５】
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アレイの駆動又は液晶シャッターアレイの駆動等により照射される光である。
【００６６】
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、ＦＡＸ、液晶プリンター及びレーザー製版等の電子写真応用分野にも幅広く適用し得るものである。
【００６７】
【実施例】
以下、実施例に従って本発明を更に詳細に説明する。なお、実施例中の「部」は「質量部」を意味する。
【００６８】
（参考例１）
直径３０ｍｍ×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工液を支持体上に浸漬コーティング法で塗布し、１４０℃で３０分間熱硬化して、膜厚が１８μｍの導電層を形成した。
【００６９】
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
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＝０．２／０．８ １５部
【００７０】
次に、この上にＮ−メトキシメチル化ナイロン５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コーティング法で塗布して、膜厚が０．７μｍの中間層を形成した。
【００７１】
次に、ＣｕＫα特性Ｘ線回折のブラッグ角（２θ±０．２°）の７．４°及び２８．２°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、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部及びシクロヘキサノン８０部を直径１ｍｍガラスビーズを用いたサンドミル装置で４時間分散した後、酢酸エチル８０部を加えて電荷発生層用分散液を調製した。これを浸漬コーティング法で塗布して、膜厚が０．２μｍの電荷発生層を形成した。
【００７２】
次いで、下記式（４）で示される正孔輸送性化合物６０部を
【００７３】
【化３】

【００７４】
モノクロロベンゼン３０部／ジクロロメタン３０部の混合溶媒中に溶解し、電荷輸送層用塗料を調製した。この塗料を前記の電荷発生層上にコーティングし、窒素雰囲気中において加速電圧１５０ＫＶ、線量２０Ｍｒａｄの条件で電子線を照射した後、引き続いて電子写真感光体の温度が１５０℃になるまでおよそ1分で昇温させその後２分間１５０℃を保持し、合計で３分間の加熱処理とした。なお電子線照射直後の電子写真感光体の温度は３０℃、電子線照射時及び加熱時の酸素濃度は８０ｐｐｍであった。更に、電子写真感光体を大気中において１４０℃で１時間後処理を行い、膜厚１３μｍの電荷輸送層を形成し、電子写真感光体を得た。
【００７５】
作製した電子写真感光体は、キヤノン（株）製複写機ＧＰ４０を用いて２２℃／５５％の環境下で評価した。電子写真感光体の電位特性については、複写機本体から現像器ユニットを取り外し、代わりに電位測定用プローブを現像位置に固定することにより測定を行った。なおその際に転写ユニットは、電子写真感光体に非接触、紙は非通紙とした。初期の電子写真感光体特性〔暗部電位Ｖｄ、光減衰感度（暗部電位６５０Ｖ設定で１５０Ｖに光減衰させるために必要な光量）、残留電位Ｖｓｌ（光減衰感度の光量の３倍の光量を照射したときの電位）〕を測定し、更に１０００００枚の通紙耐久実験を行い、画像欠陥の発生の有無の観察、電子写真感光体の削れ量を測定した。なお削れ量の測定には、渦電流式膜厚計（カールフィッシャー社製）を使用した。また、通紙耐久はプリント１枚ごとに１回停止する間欠モードとした。
【００７６】
結果を表２に示す。
【００７７】
（参考例２）
参考例１と同様にして電荷発生層までを形成した。
【００７８】
次いで下記式（５）で示されるスチリル化合物７部
【００７９】
【化４】

【００８０】
及びポリカーボネート樹脂（商品名：ユーピロンＺ８００、三菱エンジニアリングプラスチックス（株）社製）１０部をモノクロロベンゼン１０５部／ジクロロメタン３５部の混合溶媒中に溶解して調製した電荷輸送層用塗料を用いて、前記電荷発生層上に電荷輸送層を形成した。このときの電荷輸送層の膜厚は１０μｍであった。
【００８１】
次いで、下記式（６）で示される正孔輸送性化合物４５部を
【００８２】
【化５】

【００８３】
ｎ−プロピルアルコール５５部に溶解し、表面保護層用塗料を調製した。この塗料を用いて、前記電荷輸送層上に保護層を塗布したのち、窒素雰囲気中において加速電圧１５０ＫＶ、線量２０Ｍｒａｄの条件で電子線を照射した後、引き続いて電子写真感光体の温度が１５０℃になるまでおよそ２分で昇温させ、その後１分間１５０℃を保持し、合計で３分間の加熱処理とした。なお、電子線照射直後の電子写真感光体の温度は３０℃、電子線照射時及び加熱時の酸素濃度は８０ｐｐｍであった。更に、電子写真感光体を大気中において１４０℃で１時間後処理を行い、膜厚が５μｍの保護層を形成し、電子写真感光体を得た。このようにして作製した電子写真感光体を参考例１と同様に評価した。結果を表２に示す。
【００８４】
（参考例３）
参考例２における電子線の線量を２０Ｍｒａｄから５０Ｍｒａｄに変更した以外は、参考例２と同様にして電子写真感光体を作製し、評価した。結果を表２に示す。
【００８５】
（比較例１）
参考例２において、窒素中における加温時の酸素濃度を８０ｐｐｍから酸素濃度２０％（大気中）に変更した以外は、参考例２と同様にして電子写真感光体を作製し、評価した。結果を表２に示す。
【００８６】
（実施例１及び２）
参考例２において、窒素中における加温の雰囲気を表１に示した真空条件に変更した以外は、参考例２と同様にして電子写真感光体を作製し、評価した。結果を表２に示す。
【００８７】
【表１】

【００８８】
（比較例２）
参考例２において、電子線照射後の窒素中加温工程を行わない以外は、参考例２と同様に電子写真感光体を作製し、評価した。結果を表２に示す。その結果、電子写真特性は良好であったが耐久性能が大幅に低下した。
【００８９】
（比較例３）
参考例３において、電子線照射後の窒素中加温工程を行わない以外は、参考例３と同様に電子写真感光体を作製し、評価した。結果を表２に示す。その結果、比較例２と比較して向上はしたものの耐久性能は十分ではなかった。また、初期の電子写真特性が悪い傾向にあった。これは電子線照射による電子写真感光体の劣化が原因であると考えられる。
【００９０】
（比較例４）
参考例１において、電子線照射を行わなかった以外は参考例１と同様に電子写真感光体を作製したが、出来上がった電子写真感光体の表面にはタックが残っており、硬化が十分に進行していないことがわかった。よって、評価は行わなかった。
【００９１】
（比較例５）
比較例４に対して、窒素中加温の温度を１５０℃から２００℃に変更した以外は比較例４と同様に電子写真感光体を作製し、評価した。結果を表２に示す。その結果、比較例４のように出来上がった電子写真感光体表面のタックは残っておらず、見かけ上は硬化が進行したと考えられたが、初期の電子写真特性が悪く、また耐久性能は十分ではなかった。これは、電子線による重合及び架橋の開始点の生成工程がなくとも、熱による重合及び架橋が進行することを示していると考えられるが、その重合反応は十分ではないと予想される。また、電子写真感光体を高温にさらすことで、電子写真感光体の劣化が起こっているため、電子写真特性が悪化する傾向にあると推測される。
【００９２】
（比較例６）
比較例５に対して窒素中の加温のかわりに大気中において加温を行った結果、出来上がった電子写真感光体の表面にはタックが残っており、硬化が十分に進行していないことがわかった。よって評価は行わなかった。
【００９３】
【表２】

【００９４】
表２に見られるように本発明の電子写真感光体は、初期の電子写真感光体特性が良好であり、耐久での削れ量が少なくかつキズ等による画像欠陥が発生しないという従来の電子写真感光体と比較して、優れた耐久性能を示すことがわかった。
【００９５】
【発明の効果】
以上のように、本発明の電子写真感光体は電子写真特性に優れ、耐磨耗性や耐傷性に優れた効果を有する。従って、近年のプリントスピードの高速化、高プリントボリューム化、コピーコストの低減等の市場の要求に十分答えうる電子写真感光体、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、該電子写真感光体の製造方法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備えた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 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 案内手段[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member, and a method for producing the electrophotographic photosensitive member, and more specifically, an electrophotography formed by heating after radiation irradiation. The present invention relates to a photosensitive member, a process cartridge having the electrophotographic photosensitive member, an electrophotographic apparatus, and a method for manufacturing the electrophotographic photosensitive member.
[0002]
[Prior art]
  In recent years, organic photoconductive materials, which are used for electrophotographic photoreceptors, have been widely used due to their advantages such as high productivity and non-pollution. These electrophotographic photoreceptors are often used as function-separated electrophotographic photoreceptors in which a charge generation layer and a charge transport layer are laminated in order to satisfy both electrical and mechanical characteristics. On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, and optical characteristics according to the applied electrophotographic process. In particular, in an electrophotographic photosensitive member that is repeatedly used, electrical and mechanical external forces such as charging, image exposure, toner development, transfer to paper, and cleaning processing are directly applied to the surface of the electrophotographic photosensitive member. , Durability against them is required. Specifically, durability against surface wear and scratches caused by rubbing, transfer efficiency and slipperiness due to surface deterioration due to charging, and durability against deterioration of electrical characteristics such as sensitivity reduction and potential reduction are also required. Is done.
[0003]
  In general, the surface of an electrophotographic photoreceptor is a thin resin layer, and the characteristics of the resin are very important. In recent years, acrylic resins and polycarbonate resins have been put to practical use as resins that satisfy the above-mentioned conditions to some extent, but not all of the above-mentioned characteristics are satisfied with these resins, and in particular, electrophotographic photoreceptors. Therefore, it is difficult to say that the coating film hardness of the resin is sufficiently high. Even when these resins are used as the resin for forming the surface layer, there is a problem that the surface layer is worn during repeated use, and further scratches are generated. Furthermore, due to the recent demand for higher sensitivity of organic electrophotographic photoreceptors, low molecular weight compounds such as charge transport materials are often added in relatively large amounts. In this case, due to the plasticizer action of these low molecular weight materials. The film strength is remarkably lowered, and the surface layer is worn and damaged when repeatedly used. Further, when the electrophotographic photosensitive member is stored for a long period of time, the above-mentioned low molecular weight component is precipitated, resulting in a problem of layer separation.
[0004]
  As means for solving these problems, an attempt to use a curable resin as a resin for a charge transport layer is disclosed in, for example, JP-A-2-127852. Thus, the mechanical strength is increased by curing and crosslinking the charge transport layer using a curable resin as the charge transport layer resin, and the abrasion resistance and scratch resistance during repeated use are greatly improved. However, even when a curable resin is used, the low molecular weight component acts as a plasticizer in the binder resin to the last, so the problems of precipitation and layer separation as described above are not fundamental solutions. In addition, the charge transport layer composed of an organic charge transport material and a binder resin has a large dependence on the charge transport ability of the resin. For example, a curable resin with sufficiently high hardness does not have sufficient charge transport ability and is used repeatedly. In some systems, there has been room for a balance between high hardness and sufficient charge transporting ability, such as an increase in residual potential.
[0005]
  In view of the above situation, the present inventors have found that the above problem is greatly improved by an electrophotographic photoreceptor using a polymerization reaction by radiation in JP-A-11-265085 and JP-A-2000-66425. Disclosed.
[0006]
[Problems to be solved by the invention]
  However, in order to cope with the recent increase in print speed, further increase in print volume, further reduction in running cost, etc., an electrophotographic photosensitive member having further excellent durability has been studied.
[0007]
  An object of the present invention is to provide an electrophotographic photoreceptor further improved in abrasion resistance in an electrophotographic photoreceptor utilizing a polymerization reaction by radiation.
[0008]
  Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[0009]
  Still another object of the present invention is to provide a method for producing the electrophotographic photosensitive member.
[0010]
[Means for Solving the Problems]
  According to the present invention, in an electrophotographic photosensitive member having a photosensitive layer or a photosensitive layer and a protective layer on a support,
  At least one of the photosensitive layer or the protective layer is,IrradiatedAndAnd after the irradiationThe degree of vacuum is 1 × 10 ^-2 In vacuum of Pa or lessAn electrophotographic photoreceptor characterized by being a layer formed by heating, and a method for producing the electrophotographic photoreceptor are provided.
[0011]
  In addition, according to the present invention, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member are provided.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail.
[0013]
  The present invention basically uses a polymerization / crosslinking reaction by radiation, but this reaction is generally performed at room temperature, and various heat-related processes such as an ultraviolet curing process and a thermal curing process are generally performed. It is widely known that it is an advantage that no problems occur. As a result of paying attention to the temperature at the time of this polymerization / crosslinking reaction, the present inventors have confirmed that the reaction is naturally promoted by increasing the temperature at the time of radiation irradiation. As a means of increasing the temperature during radiation irradiation,
(1) Warm the irradiated object before irradiation,
(2) Warm the irradiated object during irradiation,
(3) Warm up the irradiation chamber to a predetermined temperature and insert the irradiated object.
(4) Improving the radiation absorption efficiency of the irradiated object (higher acceleration voltage or increased absorbed dose)
However, there is a concern that the apparatus / equipment is likely to be complicated, and particularly in (4), the electrophotographic characteristics and physical properties are deteriorated.
[0014]
  Therefore, as a result of further intensive studies by the present inventors, it was found that the polymerization / crosslinking reaction is sufficiently promoted not only at the time of irradiation but also at the heating after irradiation. Although the detailed mechanism has not been clarified, polymerization / crosslinking reaction proceeds from the radical generated in the system at the time of radiation irradiation as the starting point, and its growth terminal has a certain lifetime and exists stably in the system. It is considered that polymerization / crosslinking reaction further proceeds by the subsequent heating, that is, a kind of living polymerization occurs.
[0015]
  The electrophotographic photoreceptor of the present invention has a structure in which a charge generation layer and a charge transport layer are laminated in this order on a support as a photosensitive layer, or conversely, a structure in which a charge transport layer and a charge generation layer are laminated in this order, It is possible to adopt any configuration including a single layer in which a charge generation material and a charge transport material are dispersed in a binder resin. Furthermore, a surface protective layer can be formed on the photosensitive layer.
[0016]
  In this electrophotographic photosensitive member configuration, the main object of the present invention is to improve the durability of the electrophotographic photosensitive member. Therefore, the effect can be sufficiently exhibited by forming the surface layer of the electrophotographic photosensitive member by radiation irradiation and heating. Is done. Among them, from the viewpoint of electrophotographic characteristics, particularly electrical characteristics such as residual potential and durability, a charge generation layer, a function-separated type electrophotographic photosensitive member structure in which a charge transport layer is laminated in this order, or the charge generation layer, A configuration in which a protective layer is formed on a function-separated type photosensitive layer in which charge transport layers are laminated in this order is preferable. That is, it is preferable to form the charge transport layer or the protective layer by irradiation with radiation and heating.
[0017]
  The layer formed by irradiation and heating of the present invention may be any layer as long as it is polymerized or crosslinked and cured by this step. That is, any compound may be used as long as an active site such as a radical is generated by irradiation and can be polymerized or crosslinked. Among them, a compound having an unsaturated polymerizable functional group in the molecule is preferable from the viewpoints of high reactivity, high reaction rate, versatility of materials, and the like.
[0018]
  The compound having an unsaturated polymerizable functional group in the present invention is not limited to any monomer, oligomer or macromer.
[0019]
  In addition, in the case where the surface layer in the present invention is either a charge transport layer or a protective layer, both must have charge transport ability after curing, but the compound having an unsaturated polymerizable functional group is charged. In the case of a compound having no transport ability, it is preferable to ensure the charge transport ability by adding a charge transport material or a conductive material, and the compound having the unsaturated polymerizable functional group itself has a charge transport ability. In some cases, this is not the case. However, from the viewpoint of the film hardness of the surface layer and various electrophotographic characteristics, it is more preferable to use a compound having the charge transport ability such as the latter. Further, among compounds having charge transporting ability, compounds having hole transporting ability are more preferable from the viewpoint of versatility of electrophotographic processes and materials.
[0020]
  The photosensitive layer of the electrophotographic photoreceptor of the present invention is formed on a conductive support. The support body should just have electroconductivity. For example, aluminum or copper, chromium, nickel, zinc, stainless steel or other metal or alloy molded into a drum or sheet, aluminum or copper or other metal foil laminated on plastic film, aluminum, indium oxide or oxide Examples thereof include a material obtained by depositing tin or the like on a plastic film, a metal, a plastic film, paper, or the like provided with a conductive layer by applying a conductive substance alone or together with a binder resin.
[0021]
  In the present invention, an undercoat layer having a barrier function and an adhesive function can be provided between the support and the photosensitive layer. The undercoat layer is used to improve the adhesion of the photosensitive layer, improve coating properties, protect the support, cover defects on the support, improve charge injection from the support, and protect against electrical breakdown of the photosensitive layer. Formed.
[0022]
  Materials for the undercoat layer include polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, N-methoxymethylated 6 nylon, copolymer nylon, glue and gelatin Etc. The undercoat layer is formed by applying a solution prepared by dissolving these materials in a solvent suitable for each of the materials onto a support and drying it. The film thickness is preferably about 0.1 to 2 μm.
[0023]
  When the electrophotographic photoreceptor of the present invention is a function-separated type electrophotographic photoreceptor, a charge generation layer and a charge transport layer are laminated.
[0024]
  Examples of the charge generation material used for the charge generation layer include selenium-tellurium, pyrylium, thiapyrylium dyes, various central metals and crystal systems, specifically, crystal types such as α, β, γ, ε, or X type. Phthalocyanine compounds, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, monoazo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine pigments, quinocyanines and amorphous materials described in JP-A No. 54-143645 Silicon etc. are mentioned.
[0025]
  The charge generation layer is obtained by uniformly dispersing the charge generation material together with 0.3 to 4 times the amount of binder resin and solvent by a method such as a homogenizer, ultrasonic dispersion, ball mill, vibration ball mill, sand mill, attritor or roll mill. The formed dispersion is applied and dried, or formed as a single composition film such as a vapor deposition film of the charge generation material. The film thickness is preferably 5 μm or less, and particularly preferably in the range of 0.1 to 2 μm.
[0026]
  As binder resin, polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinylidene fluoride, trifluoroethylene, polyvinyl alcohol, polyvinyl acetal, polycarbonate, polyester , Polysulfone, polyphenylene oxide, polyurethane, cellulose resin, phenol resin, melamine resin, silicon resin and epoxy resin.
[0027]
  Next, the charge transport layer will be described. In the present invention, when the surface layer is a charge transport layer, the charge transport layer is a layer formed by irradiation and heating, and is composed of a compound that is polymerized or crosslinked and cured by this step. Examples of the charge transporting material include heterocyclic compounds such as poly-N-vinylcarbazole and polystyrylanthracene, polymer compounds having condensed polycyclic aromatics, heterocyclic compounds such as pyrazoline, imidazole, oxazole, triazole and carbazole, and triphenyl. Examples include low molecular weight compounds such as triarylalkane derivatives such as methane, triarylamine derivatives such as triphenylamine, phenylenediamine derivatives, N-phenylcarbazole derivatives, stilbene derivatives, and hydrazone derivatives. After being dispersed or dissolved in an appropriate solvent together with a polymerizable and crosslinkable resin and coated on the above charge generation layer, a charge transport layer is formed by a radiation and heating process described later.
[0028]
  As described above, the resin that can be polymerized / crosslinked by irradiation and heating may be any compound that can generate an active site such as a radical by irradiation and can be polymerized or crosslinked, and is generally chain polymerization. A compound having a functional group. Among them, a compound having an unsaturated polymerizable functional group in the molecule is preferable from the viewpoint of high reactivity, high reaction rate, versatility of materials, etc., and acryloyloxy group, methacryloyloxy group and styrene group are particularly preferable. Preferably, these are not limited to any of monomers, oligomers, macromers, and polymers, and can be appropriately selected or combined.
[0029]
  More specifically, the unsaturated polymerizable functional group is an acryloyloxy group represented by the following formula (1), a methacryloyloxy group represented by the following formula (2), or a styrene group represented by the following formula (3). Is preferredIn particular, an acryloyloxy group represented by the formula (1) is preferable..
[0030]
[Chemical2]

[0031]
(In the formula, Ar represents a substituted or unsubstituted arylene group, R₁Represents a hydrogen atom or a methyl group)
[0032]
  In addition, when a resin having charge transporting ability, preferably hole transporting ability and capable of being polymerized / crosslinked by irradiation and heating, a charge transporting layer is formed by itself, or the above-mentioned charge transporting material and charge transporting are used. It is possible to appropriately mix a resin that can be polymerized and cross-linked by radiation irradiation and heating that do not have the ability.
[0033]
  Resins having charge transporting ability and capable of being polymerized / crosslinked by irradiation and heating are, for example, known hole transporting compounds having the above unsaturated polymerizable functional groups, and some of known hole transporting compounds. Any compound may be used as long as it has the above unsaturated polymerizable functional group added thereto. Examples of known hole transporting compounds include hydrazone compounds, pyrazoline compounds, triphenylamine compounds, benzidine compounds, and stilbene compounds, but any compounds can be used as long as they are hole transporting compounds.
[0034]
  Further, in the present invention, in order to sufficiently ensure the hardness of the electrophotographic photoreceptor surface layer, the compound having a chain polymerizable functional group is a compound having two or more chain polymerizable functional groups in the same molecule. Is preferred.
[0035]
  In the present invention, in the case of an electrophotographic photoreceptor having a single layer structure, a photosensitive layer is formed using a solution in which at least a charge generating material, a charge transporting material, and a compound that can be polymerized and crosslinked by irradiation and heating are dispersed or dissolved. Is done. Also in this case, it is preferable to use a compound that has a charge transporting ability and can be polymerized and crosslinked by irradiation and heating, as in the case of the function-separated electrophotographic photoreceptor.
[0036]
  In the present invention, when the surface layer is a protective layer, the protective layer is a layer formed by irradiation and heating, and is composed of a compound that is polymerized or crosslinked and cured by this step.
[0037]
  In this case, the structure of the lower photosensitive layer is composed of a function-separated electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are laminated in this order, and a function separation type electrophotographic photosensitive member in which a charge transport layer and a charge generation layer are laminated in this order. Either an electrophotographic photosensitive member or a single-layer electrophotographic photosensitive member is possible, but for the reasons described above, an electrophotographic photosensitive member structure in which a charge generation layer and a charge transport layer are laminated in this order is preferable.
[0038]
  In this case, the charge generation layer is formed by the same method as described above, and the charge transport layer is formed by using the above charge transport material as styrene, vinyl acetate, vinyl chloride, acrylate ester, methacrylate ester, vinylidene fluoride, trifluoro In binder resins such as polymers and copolymers of vinyl compounds such as ethylene, polyvinyl alcohol, polyvinyl acetal, polycarbonate, polyester, polysulfone, polyphenylene oxide, polyurethane, cellulose resin, phenol resin, melamine resin, silicon resin and epoxy resin It is formed using a solution dispersed or dissolved in. In some cases, it is possible to add a compound having a compound that can be polymerized and crosslinked by irradiation and heating.
[0039]
  Since the protective layer needs to have a charge transporting ability after curing, when the compound itself that forms a protective layer by polymerization and crosslinking by irradiation and heating processes is a compound that does not have a charge transporting ability, It is preferable to ensure the charge transporting ability by adding the above-described charge transporting material or conductive material. In this case, the charge transport material may or may not have a functional group that can be polymerized / crosslinked by irradiation and heating, but in order to avoid a decrease in mechanical strength due to the plasticity of the charge transport material. The former is preferred.
[0040]
  As the conductive material, conductive fine particles such as titanium oxide and tin oxide are generally used, but in addition, a conductive polymer compound or the like can be used. This is not the case when the compound itself that forms a protective layer by polymerization and crosslinking by radiation irradiation and heating has charge transporting ability. In the present invention, from the viewpoint of film hardness of the surface layer and various electrophotography, a surface layer using a compound having a charge transporting ability such as the latter is particularly preferable.
[0041]
  In the present invention, each of the solutions can be applied by a known application method such as a dip coating method, a spray coating method, a curtain coating method, and a spin coating method. A coating method is preferred. Moreover, vapor deposition, plasma, and other known film forming methods can be appropriately selected.
[0042]
  In the present invention, various additives can be added to the photosensitive layer and the protective layer. Examples of the additives include deterioration inhibitors such as antioxidants and ultraviolet absorbers, and lubricants such as fluorine resin fine particles.
[0043]
  Next, radiation irradiation and heating will be described.
[0044]
  The radiation in the present invention includes, for example, electron beams and γ-rays as disclosed in JP-A-2000-66425. From various points such as the size, safety, cost, and versatility of the apparatus. An electron beam is preferred. In the case of electron beam irradiation, any of a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type can be used as an accelerator.
[0045]
  In the present invention in which an electrophotographic photosensitive member is formed by electron beam irradiation, the acceleration voltage and absorbed dose of the electron beam are very important factors in fully expressing the electric characteristics and durability of the electrophotographic photosensitive member. The acceleration voltage is preferably 300 KV or less, optimally 150 KV or less, and the dose is preferably in the range of 1 to 100 Mrad, more preferably 50 Mrad or less. As shown in the publication, when the acceleration voltage exceeds 300 KV or the dose exceeds 100 Mrad, the electrophotographic photosensitive member tends to deteriorate.
[0046]
  As a result of intensive studies, the present inventors have discovered that radicals that are reactive sites continue to exist for several hours or more after irradiation. According to this, by raising the temperature of the system by the heating means described later while the radicals after irradiation are present, the polymerization / crosslinking reaction can be further advanced, and even at the same dose, the curing can be further performed. It was demonstrated that a high degree film was formed. Furthermore, it has been found that when the polymerization / crosslinking reaction using heating after irradiation is used, sufficient curability can be obtained with a smaller dose than in the conventional case.
[0047]
  In other words, in the conventional method, more radicals are generated than necessary due to excess radiation energy, but in this application, the superiority of determining the radiation dose with respect to the minimum radical generation is shown. . This is, of course, a great advantage with respect to the fact that radiation can be performed on the electrophotographic photosensitive member under gentle conditions, and that the apparatus is simplified, energy is reduced, and costs are reduced.
[0048]
  The amount of radical initiation point, which is the active site of reaction, depends largely on the chemical structure of the constituent material of the layer to be polymerized / crosslinked, that is, the initiation reaction efficiency of these compounds with respect to radiation. Since it is difficult to predict and measure, it is necessary to determine the optimum constituent material and radiation irradiation conditions by evaluating the final curability at present. In the case of the compound having an unsaturated polymerizable functional group used in the present application, sufficient curability can be obtained even at a dose of about 20 Mrad or less, and depending on the material, a dose of only 1 Mrad is sufficient. It was found that curability can be obtained.
[0049]
  Next, heating will be described. The heating means in the present invention can be performed either from the outside or the inside of the electrophotographic photosensitive member. When heating from the outside, install various heaters in the vicinity of the electrophotographic photosensitive member and heat directly.LawIs mentioned. Also in the method of heating from the inside, there are a method of installing various heaters inside, a method of passing a heated fluid, and the like. Some of these heating means can be combined. In addition, the temperature of the electrophotographic photosensitive member is prepared by separately preparing a temperature measuring electrophotographic photosensitive member having the same composition,
(1) A thermo label is attached to the surface of the photoconductor.
(2) A tape-type thermocouple thermometer is brought into contact with the surface of the photoreceptor.
(3) A non-contact type radiation thermometer is disposed near the surface of the photosensitive member.
However, in order to increase the reliability of the temperature, it is preferable that the temperature of the electrophotographic photosensitive member is not integrated alone, but some of these measurement data are combined.
[0050]
  The heating temperature is preferably set so that the temperature of the electrophotographic photosensitive member is equal to or higher than room temperature, and particularly preferably set to be equal to or higher than the temperature during radiation irradiation. Electron beam irradiation is generally performed in a room temperature atmosphere of approximately 20 ° C., but when the electron beam is irradiated, the energy is absorbed by the electrophotographic photosensitive member and the surrounding medium, and these temperature increases occur. The ratio is the energy applied to the system such as acceleration voltage, beam current value, irradiation time, dose, etc., and the energy on the absorbing side, that is, the size and material of the irradiation space, the flow of the atmospheric gas, the cooling system of the device, and the electrophotographic photosensitive Depending on the heat balance such as the material structure of the body itself, the electrophotographic photosensitive member itself generally rises from room temperature to several tens of degrees centigrade at a substantial dose.
[0051]
  Here, the reason why the temperature of the electrophotographic photosensitive member is set to room temperature or higher, preferably higher than the temperature at the time of irradiation is considered to be due to the polymerization reaction mechanism. At the time of irradiation, reaction active sites are first generated in the layer to be polymerized / crosslinked, and the polymerization proceeds within the intermolecular distance where the constituent material can move at the molecular level, that is, capable of bimolecular reaction. If polymerization / crosslinking progresses to some extent, the oligomer or polymerized constituent material can no longer move at the molecular level at that temperature, and the reaction is considered to stop once. At this point, the reactive sites can exist with a certain lifetime as described above, so that at this stage, the temperature of the system is raised, allowing further movement at the molecular level, and further polymerization, It is believed that the crosslinking reaction can proceed.
[0052]
  The higher the temperature during heating, the more effective the polymerization / crosslinking reaction is. However, in the present invention intended for an electrophotographic photoreceptor, the temperature is preferably 250 ° C. or lower. When the temperature exceeds this temperature, the material of the electrophotographic photosensitive member deteriorates and the electrophotographic characteristics tend to deteriorate. More preferably, it is 200 degrees C or less, More preferably, it is 150 degrees C or less.
[0053]
  On the other hand, the lower limit of the temperature is based on the presumed mechanism that the temperature of the electrophotographic photosensitive member at the time of heating is higher than the temperature of the electrophotographic photosensitive member at the time of radiation irradiation to promote the polymerization / crosslinking reaction as described above. It is essential that the temperature be set at least several tens of degrees C higher than the temperature of the photosensitive member at the time of radiation irradiation, preferably 50 ° C. or higher, and it is preferable to set the set temperature as high as possible unless particularly harmful.
[0054]
  The heating time is approximately several seconds to several tens of minutes. However, rather than the heating time, the set temperature, that is, the temperature reached by the electrophotographic photosensitive member greatly affects the curability. The heating time substantially includes the temperature rising time and the reached temperature holding time. Although the temperature rise time varies greatly depending on the type of heating means and electrophotographic photosensitive member, especially the material of the substrate, it is preferable to select a means that reaches a predetermined temperature in a few seconds to a few minutes. However, it is presumed that a long time is not a problem in terms of characteristics, but it is not preferable in production.
[0055]
  The ultimate temperature holding time is preferably set from several seconds to several tens of minutes after reaching the set temperature from the viewpoint of preventing overheating / stabilizing the ultimate temperature. There is no particular problem with completing the heating process in a shorter time than these times, that is, within a few seconds, but it is not practical in terms of apparatus control problems and increased load. On the other hand, it is possible to perform a heat treatment longer than these times, but it is not preferable from the viewpoint of productivity.
[0056]
  The atmosphere for the heating process isHeavyConsidering the mechanism of the coupling / crosslinking reaction, in order to avoid the deactivation of the reactive sites due to oxygen as much as possible,The degree of vacuum is 1 × 10 ^-2 It is essential to be in a vacuum of Pa or less,1x10^-FiveMore preferably less than PaYes.
[0057]
  The time from the irradiation to the heat treatment is preferably set to a short time for the purpose of avoiding the deactivation of the reactive sites as much as before, and the heat treatment can be carried out continuously after the irradiation. Although it is preferable, when continuous processing is difficult due to problems in the apparatus, a standing time of several minutes to several hours may occur between the two. However, even when this time is an extremely short time, polymerization inhibition due to oxygen may occur. Therefore, attention should be paid to the oxygen concentration in the atmosphere.
[0058]
  Note that these deactivation rates are slow.ChishinIn the case of passing through the air, or when the radical deactivation rate is slow depending on the type of material, the curability does not change even after passing through a standing period of several hours. Since the radical amount in the polymerized / crosslinked layer immediately after irradiation and after standing for several hours was measured by electron spin resonance, no decrease in the number of radicals was confirmed. It is also possible to go through. These heating methods can be combined with several kinds of means.
[0059]
  FIG. 1 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.
[0060]
  In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 2 in a direction indicated by an arrow at a predetermined peripheral speed. In the rotating process, the electrophotographic photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the primary charging unit 3, and then from an exposure unit (not shown) such as slit exposure or laser beam scanning exposure. The exposure light 4 subjected to intensity modulation corresponding to the time-series electric digital image signal of the target image information to be output is received. In this way, electrostatic latent images corresponding to the target image information are sequentially formed on the peripheral surface of the electrophotographic photoreceptor 1.
[0061]
  The formed electrostatic latent image is then developed with toner by the developing means 5 and is taken out from a paper feeding unit (not shown) between the electrophotographic photoreceptor 1 and the transfer means 6 in synchronism with the rotation of the electrophotographic photoreceptor 1. The toner image formed and supported on the surface of the electrophotographic photosensitive member 1 is sequentially transferred by the transfer means 6 to the transferred transfer material 7.
[0062]
  The transfer material 7 that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member, introduced into the image fixing means 8, and subjected to image fixing to be printed out as an image formed product (print, copy). .
[0063]
  After the image transfer, the surface of the electrophotographic photosensitive member 1 is cleaned by removing the transfer residual toner by the cleaning unit 9, and is further subjected to charge removal processing by the pre-exposure light 10 from the pre-exposure unit (not shown). Used repeatedly 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.
[0064]
  In the present invention, among the above-described components such as the electrophotographic photosensitive member 1, the primary charging unit 3, the developing unit 5 and the cleaning unit 9, a plurality of components are housed in a container and integrally combined as a process cartridge. The 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 together with the electrophotographic photosensitive member 1 to form a cartridge, and is attached to and detached from the apparatus main body using a guide unit 12 such as a rail of the apparatus main body. A flexible process cartridge 11 can be obtained.
[0065]
  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 emitted by driving the LED array or the liquid crystal shutter array.
[0066]
  The electrophotographic photosensitive member of the present invention can be used not only for electrophotographic copying machines but also widely applicable to electrophotographic application fields such as laser beam printers, CRT printers, LED printers, FAX, liquid crystal printers, and laser plate making. It is.
[0067]
【Example】
  Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “part” means “part by mass”.
[0068]
  (Reference example 1)
  An aluminum cylinder having a diameter of 30 mm × 357.5 mm is used as a support, and a coating liquid composed of the following materials is applied to the support by a dip coating method, and is thermally cured at 140 ° C. for 30 minutes to obtain a film thickness. Formed a conductive layer of 18 μm.
[0069]
  Conductive pigment: SnO₂Coated barium sulfate 10 parts
  Resistance control pigment: Titanium oxide 2 parts
  Binder resin: 6 parts of phenol resin
  Leveling material: 0.001 part of silicone oil
  Solvent: methanol / methoxypropanol = 0.2 / 0.8 15 parts
[0070]
  Next, a solution obtained by dissolving 5 parts of N-methoxymethylated nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol is applied by a dip coating method to form an intermediate layer having a film thickness of 0.7 μm. Formed.
[0071]
  Next, 4 parts of hydroxygallium phthalocyanine having strong peaks at 7.4 ° and 28.2 ° of the Bragg angle (2θ ± 0.2 °) of CuKα characteristic X-ray diffraction, polyvinyl butyral (trade name: ESREC BX-1) 2 parts of Sekisui Chemical Co., Ltd.) and 80 parts of cyclohexanone were dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 4 hours, and then 80 parts of ethyl acetate was added to prepare a charge generation layer dispersion. This was applied by a dip coating method to form a charge generation layer having a thickness of 0.2 μm.
[0072]
  Next, 60 parts of the hole transporting compound represented by the following formula (4)
[0073]
[Chemical3]

[0074]
It was dissolved in a mixed solvent of 30 parts of monochlorobenzene / 30 parts of dichloromethane to prepare a charge transport layer coating material. This paint is coated on the charge generation layer and irradiated with an electron beam in a nitrogen atmosphere under the conditions of an acceleration voltage of 150 KV and a dose of 20 Mrad, and then approximately 1 minute until the temperature of the electrophotographic photosensitive member reaches 150 ° C. Then, the temperature was maintained at 150 ° C. for 2 minutes, and the heat treatment was performed for a total of 3 minutes. The temperature of the electrophotographic photosensitive member immediately after the electron beam irradiation was 30 ° C., and the oxygen concentration during electron beam irradiation and heating was 80 ppm. Further, the electrophotographic photoreceptor was post-treated at 140 ° C. for 1 hour in the atmosphere to form a 13 μm-thick charge transport layer to obtain an electrophotographic photoreceptor.
[0075]
  The produced electrophotographic photosensitive member was evaluated in a 22 ° C./55% environment using a copying machine GP40 manufactured by Canon Inc. The potential characteristics of the electrophotographic photosensitive member were measured by removing the developing unit from the copying machine main body and fixing the potential measuring probe at the developing position instead. At that time, the transfer unit was not in contact with the electrophotographic photosensitive member, and the paper was not passed. Initial electrophotographic photosensitive member characteristics [dark portion potential Vd, light attenuation sensitivity (light amount necessary for light attenuation to 150 V when dark portion potential is set to 650 V), residual potential Vsl (light amount three times as large as light attenuation sensitivity) )], And a 100,000 sheet passing durability test was conducted to observe the occurrence of image defects and the amount of abrasion of the electrophotographic photosensitive member. An eddy current film thickness meter (manufactured by Karl Fischer) was used for measurement of the amount of scraping. In addition, the sheet passing durability is an intermittent mode in which the printing is stopped once for each print.
[0076]
  Table the results2Shown in
[0077]
  (Reference example 2)
  Reference example 1In the same manner as described above, the layers up to the charge generation layer were formed.
[0078]
  Next, 7 parts of a styryl compound represented by the following formula (5)
[0079]
[Chemical4]

[0080]
And 10 parts of polycarbonate resin (trade name: Iupilon Z800, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) dissolved in a mixed solvent of 105 parts of monochlorobenzene / 35 parts of dichloromethane, A charge transport layer was formed on the charge generation layer. The film thickness of the charge transport layer at this time was 10 μm.
[0081]
  Next, 45 parts of a hole transporting compound represented by the following formula (6)
[0082]
[Chemical5]

[0083]
It melt | dissolved in 55 parts of n-propyl alcohol, and the coating material for surface protection layers was prepared. Using this paint, after applying a protective layer on the charge transport layer, after irradiating an electron beam in a nitrogen atmosphere under the conditions of an acceleration voltage of 150 KV and a dose of 20 Mrad, the temperature of the electrophotographic photoreceptor is subsequently 150 ° C. Then, the temperature was raised in about 2 minutes until the temperature became 150 ° C., and then kept at 150 ° C. for 1 minute for a total of 3 minutes of heat treatment. The temperature of the electrophotographic photoreceptor immediately after electron beam irradiation was 30 ° C., and the oxygen concentration during electron beam irradiation and heating was 80 ppm. Further, the electrophotographic photosensitive member was post-treated at 140 ° C. for 1 hour in the atmosphere to form a protective layer having a thickness of 5 μm to obtain an electrophotographic photosensitive member. The electrophotographic photoreceptor thus produced isReference example 1And evaluated in the same manner. Table the results2Shown in
[0084]
  (Reference example 3)
  Reference example 2The electron beam dose at 20 Mrad?To 50MradExcept for changes,Reference example 2An electrophotographic photoreceptor was prepared and evaluated in the same manner as. ResultTable2Shown in
[0085]
  (Comparative Example 1)
  Reference example 2The oxygen concentration during heating in nitrogen from 80 ppmOxygen concentration 20% (in air)Except to change toReference example 2An electrophotographic photoreceptor was prepared and evaluated in the same manner as. ResultTable2Shown in
[0086]
  (Example1 and 2)
  Reference example 2Shows the atmosphere of heating in nitrogen.1Except for changing to the vacuum conditions shown inReference example 2In the same manner as above, an electrophotographic photoreceptor was prepared and evaluated. Table the results2Shown in
[0087]
[Table 1]

[0088]
  (Comparative example2)
  Reference example 2In, except not performing the heating process in nitrogen after electron beam irradiation,Reference example 2An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table the results2Shown in As a result, the electrophotographic characteristics were good, but the durability performance was greatly reduced.
[0089]
  (Comparative example3)
  Reference example 3In, except not performing the heating process in nitrogen after electron beam irradiation,Reference example 3An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table the results2Shown in As a result, comparative example2Despite improvement, durability performance was not sufficient. Also, the initial electrophotographic characteristics tended to be poor. This is considered to be caused by deterioration of the electrophotographic photosensitive member due to electron beam irradiation.
[0090]
  (Comparative example4)
  Reference example 1In, except that the electron beam irradiation was not performedReference example 1The electrophotographic photosensitive member was produced in the same manner as in Example 1, but the tack remained on the surface of the completed electrophotographic photosensitive member, and it was found that curing did not proceed sufficiently. Therefore, evaluation was not performed.
[0091]
  (Comparative example5)
  Comparative example4On the other hand, the comparative example except that the temperature in nitrogen was changed from 150 ° C to 200 ° C4An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table the results2Shown in As a result, comparative example4The surface of the electrophotographic photosensitive member thus finished did not remain tacky, and it seemed that curing had progressed, but the initial electrophotographic characteristics were poor and the durability performance was not sufficient. This is considered to indicate that the polymerization and crosslinking by heat proceed even without the step of generating the starting point of polymerization and crosslinking by electron beam, but the polymerization reaction is expected to be insufficient. Further, since the electrophotographic photosensitive member is deteriorated by exposing the electrophotographic photosensitive member to a high temperature, it is presumed that the electrophotographic characteristics tend to deteriorate.
[0092]
  (Comparative example6)
  Comparative example5On the other hand, as a result of heating in the atmosphere instead of heating in nitrogen, it was found that tack remained on the surface of the completed electrophotographic photosensitive member and curing did not proceed sufficiently. Therefore, evaluation was not performed.
[0093]
[Table 2]

[0094]
  As can be seen from Table 2, the electrophotographic photosensitive member of the present invention has a good initial electrophotographic photosensitive member property, has a small amount of wear in durability, and does not cause image defects due to scratches or the like. It was found that it showed superior durability performance compared to the body.
[0095]
【The invention's effect】
  As described above, the electrophotographic photosensitive member of the present invention is excellent in electrophotographic characteristics and has an effect of excellent wear resistance and scratch resistance. Accordingly, an electrophotographic photosensitive member that can sufficiently meet market demands such as recent increase in printing speed, increase in print volume, and reduction in copy cost, process cartridge and electrophotographic apparatus having the electrophotographic photosensitive member, and electrophotography It has become possible to provide a method for producing a photoreceptor.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.
[Explanation of symbols]
    1 Electrophotographic photoreceptor
    2 axis
    3 Charging means
    4 exposure light
    5 Development means
    6 Transfer means
    7 Transfer material
    8 Fixing means
    9 Cleaning means
  10 Pre-exposure light
  11 Process cartridge
  12 Guide means

Claims (13)

In an electrophotographic photosensitive member having a photosensitive layer or a photosensitive layer and a protective layer on a support,
At least one layer of the photosensitive layer or the protective layer may, be exposed to radiation, and a layer formed by vacuum after the irradiation is heated at 1 × 10 ^-2 Pa in a vacuum of An electrophotographic photoreceptor characterized by the above. The electrophotographic photosensitive member according to claim 1, wherein the temperature of the electrophotographic photosensitive member during heating is higher than the temperature during radiation irradiation. The temperature of the electrophotographic photosensitive member at the time of heating, electrophotographic photosensitive member according to claim 1 or 2 is 50 ° C. or higher 250 ° C. or less. Said radiation, electrophotographic photosensitive member according to any one of claims 1 to 3 which is an electron beam. The layer formed by being irradiated with the radiation and heated in a vacuum having a vacuum degree of 1 × 10 ⁻² Pa or less after the radiation irradiation polymerizes or crosslinks a compound having a chain polymerizable functional group. the electrophotographic photosensitive member according to any one of claims 1 to 4, which is a layer that has been cured by. The chain-polymerizable functional group, an electrophotographic photosensitive member according to claim 5 which is an unsaturated polymerizable functional group. The unsaturated polymerizable functional group, an electrophotographic photosensitive member according to claim 11 is acryloyloxy group represented by the following formula (1).

The chain-polymerizable compound having a functional group, an electrophotographic photosensitive member according to any one of claims 5-7 having a charge transport group. The electrophotographic photosensitive member according to claim 8 , wherein the charge transporting group is a hole transporting group. The chain-polymerizable compound having a functional group, an electrophotographic photosensitive member according to any one of claims 5-9 having two or more chain polymerizable functional groups in the same molecule. An electrophotographic photosensitive member according to any one of claims 1-10, charging 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 1-10, a charging means, an exposure means, the electrophotographic apparatus, characterized in that it comprises a developing means and a transfer means. In the method for producing an electrophotographic photosensitive member having a photosensitive layer or a photosensitive layer and a protective layer on a support, at least one layer of the photosensitive layer or the protective layer,
A method for producing an electrophotographic photosensitive member, comprising: a step of irradiating radiation; and a step of heating in a vacuum having a vacuum degree of 1 × 10 ⁻² Pa or less after the radiation irradiation.

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