JP4137396B2 - Electrophotographic photosensitive member and electrophotographic apparatus using the same - Google Patents

Description

（式中、Ｒ₁₁は炭素数が８〜２５の直鎖、分岐、飽和又は不飽和いずれでもよい脂肪族炭化水素基を表し、Ｒ₁₂は炭素数が４以下の直鎖、分岐いずれでもよい炭化水素基を表す。）
【００１３】
【化７】

（式中、Ｒ₂₁、Ｒ₂₂、Ｒ₂₃、Ｒ₂₄及びＲ₂₅はそれぞれ独立して、水素原子、ハロゲン原子、ヒドロキシ基、炭素数１〜８好ましく１〜６の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基またはアルコキシ基を表し、Ｒ₂₆は炭素数が８〜２５の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基を表す。）
【００１４】
【化８】

（式中、Ｒ₃₁、Ｒ₃₂、Ｒ₃₃、Ｒ₃₄及びＲ₃₅はそれぞれ独立して、水素原子、ハロゲン原子、ヒドロキシ基、炭素数１〜８好ましく１〜６の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基またはアルコキシ基を表し、Ｒ₃₆は炭素数が８〜２５の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基を表す。）
【００１５】
従って、本発明によれば、導電性基体上に感光層を有する電子写真感光体において、感光層中に少なくとも下記一般式（Ｉ）、（II）、（III）で表される化合物の少なくとも１種が含有されてなることを特徴とする電子写真感光体が提供される。
【化９】

（式中、Ｒ₁₁は炭素数が８〜２５の直鎖、分岐、飽和又は不飽和いずれでもよい脂肪族炭化水素基を表し、Ｒ₁₂は炭素数が４以下の直鎖、分岐いずれでもよい炭化水素基を表す。）
【化１０】

（式中、Ｒ₂₁、Ｒ₂₂、Ｒ₂₃、Ｒ₂₄及びＲ₂₅はそれぞれ独立して、水素原子、ハロゲン原子、ヒドロキシ基、炭素数１〜８好ましくは１〜６の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基またはアルコキシ基を表し、Ｒ₂₆は炭素数が８〜２５の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基を表す。）
【化１１】

（式中、Ｒ₃₁、Ｒ₃₂、Ｒ₃₃、Ｒ₃₄及びＲ₃₅はそれぞれ独立して、水素原子、ハロゲン原子、ヒドロキシ基、炭素数１〜８好ましくは１〜６の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基またはアルコキシ基を表し、Ｒ₃₆は炭素数が８〜２５の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基を表す。）
【００１６】
また、本発明によれば、帯電手段によって潜像形成準備を行い、その後の像露光によって潜像形成を行う電子写真装置において、上記の電子写真感光体を用いることを特徴とする電子写真装置が提供される。
【００１７】
【発明の実施の形態】
以下、本発明をさらに詳細に説明する。
前記一般式（Ｉ）で表される化合物の具体例としては、ラウリン酸メチル、ラウリン酸エチル、ラウリン酸イソプロピル、ラウリン酸ｎ−ブチル、ラウリン酸イソブチル、パルミティン酸メチル、パルミティン酸エチル、パルミティン酸イソプロピル、パルミティン酸ｎ−ブチル、パルミティン酸イソブチル、ステアリン酸メチル、ステアリン酸エチル、ステアリン酸ｎ−ブチル、ステアリン酸イソブチル、オレイン酸メチル、オレイン酸エチル、オレイン酸ｎ−ブチル等が挙げられる。
【００１８】
前記一般式（II）で表される化合物の具体例としては、ラウリルベンゾエート、パルミティルベンゾエート、ステアリルベンゾエート、オレイルベンゾエート、ラウリルサリチレート、パルミティルサリチレート、ステアリルサリチレート、オレイルサリチレート、ラウリルｏ−アニセート、パルミティルｍ−アニセート、ステアリルｏ−アニセート、オレイルｐ−アニセート、ラウリルｏ−トルエート、パルミティルｍ−トルエート、ステアリルｏ−トルエート、オレイルｐ−トルエート、２−クロロ安息香酸ラウリルエステル、３−クロロ安息香酸パルミティルエステル、２−クロロ安息香酸ステアリルエステル、４−クロロ安息香酸オレイルエステル等が挙げられる。
【００１９】
前記一般式（III）で表されるこのような化合物の具体例としては、ラウリン酸フェニル、パルミティン酸フェニル、ステアリン酸フェニル、オレイン酸フェニル、ラウリン酸−２−ヒドロキシ−フェニル、パルミティン酸−３−ヒドロキシ−フェニル、ステアリン酸−２−ヒドロキシ−フェニル、オレイン酸−４−ヒドロキシ−フェニル、ラウリン酸−２−メトキシ−フェニル、パルミティン酸−３−メトキシ−フェニル、ステアリン酸−２−メトキシ−フェニル、オレイン酸−４−メトキシ−フェニル、ラウリン酸−２−メチル−フェニル、パルミティン酸−３−メチル−フェニル、ステアリン酸−２−メチル−フェニル、オレイン酸−４−メチル−フェニル、ラウリン酸−２−クロロ−フェニル、パルミティン酸−３−クロロ−フェニル、ステアリン酸−２−クロロ−フェニル、オレイン酸−４−クロロ−フェニル等が挙げられる。
【００２０】
さらに本発明によれば、前記一般式（II）及び一般式（III）に示される化合物のうち、後述の一般式（IIa）及び一般式（IIIa）に示される化合物を用いることが効果の点でより好ましい。
【化１２】

（式中、Ｒ₂₁は水素原子、ハロゲン原子、ヒドロキシ基、炭素数１〜８好ましくは１〜６の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基またはアルコキシ基などを表し、Ｒ₂₆′は炭素数が１２〜２２の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基を表す。）
【化１３】

（式中、Ｒ₃₁は水素原子、ハロゲン原子、ヒドロキシ基、炭素数１〜８好ましくは１〜６の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基又はアルコキシ基などを表し、Ｒ₃₆′は炭素数が１２〜２２の直鎖、分岐、飽和又は不飽和のいずれでもよいアルキル基を表す。）
【００２１】
なお、本発明の前記一般式（II）、（IIa）、（III）、（IIIa）における式中Ｒ₂₁、Ｒ₂₂、Ｒ₂₃、Ｒ₂₄、Ｒ₂₅、Ｒ₃₁、Ｒ₃₂、Ｒ₃₃、Ｒ₃₄、Ｒ₃₅のアルキル基としては炭素数１〜６の低級アルキル基が好ましく、特にメチル基、エチル基が好ましい。またアルコキシ基としてはメトキシ基、エトキシ基等が好ましい。また式中、Ｒ₂₆′、Ｒ₃₆′のアルキル基は直鎖、分岐、飽和、不飽和のいずれでもよいが、好ましくは直鎖である。
【００２２】
さらに本発明によれば、前記一般式（Ｉ）（II）（IIa）（III）（IIIa）で示される化合物の少なくとも１種の添加量は、感光層又は電荷輸送層に含有される結着樹脂１００重量部に対し０．１〜２０重量部であることが効果の点でより好ましい。添加量が前記の範囲よりも少ないと、帯電安定性、耐ガス性に効果が小さく、前記の範囲よりも多い場合は、繰り返し使用時の残留電位が上昇しやすくなる。
【００２３】
本発明において、一般式（Ｉ）（II）（IIa）（III）（IIIa）のいずれかの化合物を感光層及び電荷輸送層中に含むことにより耐ガス性および静電的な耐久性が極めて良好となる理由は明らかでないが、化合物の構造が長鎖と短鎖の両方を含むために、感光層や電荷輸送層中での相溶性が高く、かつ化合物が空隙に入りこみやすくガス透過性を低下させることが可能になると考えられる。さらに、鎖長の差に起因する化合物内の極性が感光層や電荷輸送層中で熱励起キャリアの移動を防ぐ役割を果たすと考えられる。
【００２４】
また、高画質化を達成する手段として、電荷輸送層を薄膜にして電荷移動時の拡散を少なくする方法が挙げられるが、薄膜になるに従いガス透過量が増加することや感光層の電界強度が高くなることから、上記本発明の化合物を含有することで、帯電安定性、繰り返し安定性や耐ガス性の効果がより顕著になる。さらに、高画質デジタル複写機やプリンターによって、繰り返し使用に伴い感光層が削れた際にも、上記と同様な理由から、化合物を含有することで帯電安定性、繰り返し安定性や耐ガス性の効果がより顕著になる。
【００２５】
本発明に用いる電子写真感光体用導電性支持体は体積抵抗が１０¹⁰Ω・ｃｍ以下の導電性を示すものが挙げられ、例えば、アルミニウム、ニッケル、クロム、ニクロム、銅、金、銀、白金などの金属、酸化スズ、酸化インジウムなどの金属酸化物を、蒸着またはスパッタリングにより、フィルム状もしくは円筒状のプラスチック、紙に被覆したものや、ＪＩＳ３００３系、ＪＩＳ５０００系、ＪＩＳ６０００系等のアルミニウム合金を、ＥＩ法、ＥＤ法、ＤＩ法、ＩＩ法など一般的な方法により管状に成形をおこなったもの、さらにはダイヤモンドバイト等による表面切削加工や研磨、陽極酸化処理等を行ったものを用いることができる。また、特開昭５２−３６０１６号公報に開示されたエンドレスニッケルベルト、エンドレスステンレスベルトも導電性支持体として用いる事ができる。
【００２６】
支持体上に形成する感光層は、電荷発生機能と電荷輸送機能を合わせ持つ単層型の感光層や、電荷発生物質を含有する電荷発生層および電荷輸送物質を含有する電荷輸送層を積層した積層型の感光層のいずれでもよい。また、支持体上から感光層への電荷注入の防止や、干渉縞防止の目的のため、支持体と感光層との間に中間層を設けてもよい。
【００２７】
中間層の構成は、結着樹脂や結着樹脂中に粒子を分散したものが用いられ、結着樹脂としてはポリビニルアルコール、ニトロセルロース、ポリアミド、ポリ塩化ビニル等の熱可塑性樹脂、ポリウレタン、アルキッド−メラミン樹脂などの熱硬化性樹脂などを利用することができる。中間層に分散させる粒子としては酸化チタン、酸化アルミニウム、酸化錫、酸化亜鉛、酸化ジルコニウム、酸化マグネシウム、シリカ及びそれらの表面処理品が用いられ、酸化チタンが分散性、電気的特性においてより好ましく、ルチル型とアナターゼ型いずれのものも用いることが可能である。
【００２８】
本発明における中間層を形成するには、例えば上述の結着樹脂を有機溶剤中に溶解し、その溶液中に上述の粒子をボールミル、サンドミル等の手段で分散し、支持体上に塗布、乾燥すれば良い。中間層の厚みは１０μｍ以下、好ましくは０．１〜６μｍである。
【００２９】
電荷発生層は電荷発生物質を主成分とする層であり、必要に応じてバインダー樹脂が用いられる。
電荷発生物質としては、無機系材料あるいは有機系材料のいずれも用いることができる。無機系材料としては、結晶セレン、アモルファスセレン、セレン−テルル、セレン−テルル−ハロゲン、セレン−ヒ素等のセレン化合物やアモルファスシリコンなどが挙げられる。アモルファスシリコンにおいては、ダングリングボンドを水素原子、ハロゲン原子でターミネートしたものや、ホウ素原子、リン原子等をドープしたものが良好に使用される。
【００３０】
一方、有機系材料としては、公知の材料を用いることが出来る。例えば、金属フタロシアニン、無金属フタロシアニンなどのフタロシアニン系顔料、アズレニウム塩顔料、スクエアリツク酸メチン顔料、カルバゾール骨格を有するアゾ顔料、トリフェニルアミン骨格を有するアゾ顔料、ジフェニルアミン骨格を有するアゾ顔料、ジベンゾチオフェン骨格を有するアゾ顔料、フルオレノン骨格を有するアゾ顔料、オキサジアゾール骨格を有するアゾ顔料、ビススチルベン骨格を有するアゾ顔料、ジスチリルオキサジアゾール骨格を有するアゾ顔料、ジスチリルカルバゾール骨格を有するアゾ顔料、ペリレン系顔料、アントラキノン系または多環キノン系顔料、キノンイミン系顔料、ジフェニルメタン及びトリフェニルメタン系顔料、ベンゾキノン及びナフトキノン系顔料、シアニン及びアゾメチン系顔料、インジゴイド系顔料、ビスベンズイミダゾール系顔料などが挙げられる。これらの電荷発生物質は、単独または２種以上の混合物として用いることができる。
【００３１】
必要に応じて用いられる結着樹脂としては、ポリアミド、ポリウレタン、エポキシ樹脂、ポリケトン、ポリカーボネート、シリコーン樹脂、アクリル樹脂、ポリビニルブチラール、ポリビニルホルマール、ポリビニルケトン、ポリスチレン、ポリ−Ｎ−ビニルカルバゾール、ポリアクリルアミドなどが挙げられる。これらの結着樹脂は、単独または２種以上の混合物として用いることができる。また、電荷発生層には、必要に応じて電荷輸送物質を添加してもよい。
【００３２】
電荷発生層を形成する方法としては、大別すると、真空薄膜作製法と溶液分散系からのキャスティング法とが挙げられる。真空薄膜作製法としては、真空蒸着法、グロー放電分解法、イオンプレーティング法、スパッタリング法、反応性スパッタリング法、ＣＶＤ法などが挙げられ、上述した無機系材料あるいは有機系材料を用いて電荷発生層が良好に形成できる。また、キャスティング法によって電荷発生層を形成するには、上述した無機系もしくは有機系電荷発生物質を必要に応じてバインダー樹脂と共にテトラヒドロフラン、シクロヘキサノン、ジオキサン、ジクロロエタン、ブタノン等の溶媒を用いてボールミル、アトライター、サンドミルなどにより分散し、分散液を適度に希釈して塗布し乾燥させればよい。塗布方法としては、浸漬塗工法、スプレーコート法、ビードコート法などを用いることができる。
【００３３】
このようにして形成される電荷発生層の膜厚は、０．０１〜５μｍ程度が適当であり、特に０．０５〜２μｍが好ましい。
【００３４】
電荷輸送層は電荷輸送物質を主成分としてなる層であり、電荷輸送物質およびバインダー樹脂、さらに本発明に示される前記一般式（Ｉ）（II）（IIa）（III）（IIIa）の化合物の少なくとも１種を適当な溶剤、例えば、テトラヒドロフラン、ジオキサン、トルエン、モノクロルベンゼン、ジクロルエタン、塩化メチレン、シクロヘキサノンなどに溶解あるいは分散し、その溶液あるいは分散液を塗布し乾燥させることにより形成することができる。また、電荷輸送層には、必要により、可塑剤、レベリング剤、酸化防止剤などを添加することもできる。
【００３５】
電荷輸送物質には、正孔輸送物質と電子輸送物質とがある。
【００３６】
電子輸送物質としては、例えば、クロルアニル、ブロムアニル、テトラシアノエチレン、テトラシアノキノジメタン、２，４，７−トリニトロ−９−フルオレノン、２，４，５，７−テトラニトロキサントン、２，４，８−トリニトロチオキサントン、２，６，８−トリニトロ−４Ｈ−インデノ［１，２−ｂ］チオフェン−４−オン、１，３，７−トリニトロジベンゾチオフェン−５，５−ジオキサイド、３，５−ジメチル−３′，５′−ジターシヤリーブチル−４，４′−ジフェノキノンなどの公知の電子受容性物質が挙げられる。これらの電子輸送物質は単独または２種以上の混合物として用いることができる。
【００３７】
また、正孔輸送物質としては、オキサゾール誘導体、オキサジアゾール誘導体、イミダゾール誘導体、トリフェニルアミン誘導体、９−（ｐ−ジエチルアミノスチリルアントラセン）、１，１−ビス−（４−ジベンジルアミノフェニル）プロパン、スチリルアントラセン、スチリルピラゾリン、フェニルヒドラゾン類、α−フェニルスチルベン誘導体、チアゾール誘導体、トリアゾール誘導体、フェナジン誘導体、アクリジン誘導体、ベンゾフラン誘導体、ベンズイミダゾール誘導体、チオフェン誘導体などが挙げられ、これらの正孔輸送物質は単独または２種以上の混合物として用いることができる。
【００３８】
電荷輸送層に用いられる結着樹脂としては、ポリカーボネート（ビスフェノ−ルＡ型、ビスフェノ−ルＺ型等）、ポリエステル、メタクリル樹脂、アクリル樹脂、ポリエチレン、塩化ビニル、酢酸ビニル、ポリスチレン、フェノ−ル樹脂、エポキシ樹脂、ポリウレタン、ポリ塩化ビニリデン、アルキッド樹脂、シリコン樹脂、ポリビニルカルバゾール、ポリビニルブチラール、ポリビニルホルマール、ポリアクリレート、ポリアクリルアミド、フェノキシ樹脂などが挙げられる。これらの結着樹脂は、単独または２種以上の混合物として用いることが出来る。結着樹脂の使用量は、電荷輸送物質１００重量部に対して０〜１５０重量部が適当である。
【００３９】
また、結着樹脂としては、結着樹脂としての機能および電荷輸送物質としての機能を有する高分子電荷輸送物質を用いることもできる。このような高分子電荷輸送物質としては、（ａ）主鎖および／または側鎖にカルバゾール環を有する重合体、例えば、ポリ−Ｎ−ビニルカルバゾール、特開昭５０−８２０５６号公報、特開昭５４−９６３２号公報、特開昭５４−１１７３７号公報、特開平４−１８３７１９号公報に記載の化合物などが例示できる。（ｂ）主鎖および／または側鎖にヒドラゾン構造を有する重合体、例えば、特開昭５７−７８４０２号公報、特開平３−５０５５５号公報に記載の化合物などが例示できる。（ｃ）ポリシリレン重合体、例えば、特開昭６３−２８５５５２号公報、特開平５−１９４９７号公報、特開平５−７０５９５号公報に記載の化合物などが例示できる。（ｄ）主鎖および／または側鎖に第３級アミン構造を有する重合体、例えば、Ｎ，Ｎ−ビス（４−メチルフェニル）−４−アミノポリスチレン、特開平１−１３０６１号公報、特開平１−１９０４９号公報、特開平１−１７２８号公報、特開平１−１０５２６０号公報、特開平２−１６７３３５号公報、特開平５−６６５９８号公報、特開平５−４０３５０号公報に記載の化合物などが例示できる。
このようにして形成される電荷輸送層の膜厚は、５〜１００μｍ程度が適当である。
【００４０】
レベリング剤としては、ジメチルシリコーンオイル、メチルフェニルシリコーンオイルなどのシリコーンオイル類や、側鎖にパーフルオロアルキル基を有するポリマーあるいはオリゴマーが使用され、その使用量は、バインダー樹脂に対して０〜１重量部程度が適当である。
【００４１】
酸化防止剤としては、ヒンダードフェノール系化合物、硫黄系化合物、燐系化合物、ヒンダードアミン系化合物、ピリジン誘導体、ピペリジン誘導体、モルホリン誘導体等の酸化防止剤を使用でき、その使用量は結着樹脂１００重量部に対して０〜５重量部程度が適当である。
【００４２】
単層型感光体は、電荷発生物質と電荷輸送物質、結着樹脂、さらに本発明に示される前記一般式（Ｉ）（II）（IIa）（III）（IIIa）の化合物の少なくとも１種等からなる。電荷発生物質および電荷輸送物質としては、前記の材料を用いることができる。
【００４３】
このような単層型の感光層を形成するには、電荷発生物質、電荷輸送物質および結着樹脂を適当な溶剤、例えばテトラヒドロフラン、シクロヘキサノン、ジオキサン、ジクロロエタン、ブタノンなどの溶剤にボールミル、アトライター、サンドミルなどにより溶解ないし分散させ、これを適度に希釈して塗布し乾燥させればよい。塗布は浸債塗工法、スプレーコート法、ビードコート法などを用いて行なうことができる。結着樹脂としては、電荷輸送層の結着樹脂として例示した結着樹脂をそのまま用いることができ、また電荷発生層の結着樹脂として例示した結着樹脂と混合して用いてもよい。単層型の感光層には、必要により可塑剤やレべリング剤、酸化防止剤などを添加することもできる。また、ピリリウム系染料およびビスフェノールＡ型ポリカーボネートから形成される共晶錯体に、電荷輸送物質を添加した単層型の感光層も、適当な溶媒を用い上記と同様な塗工法により形成することができる。
【００４４】
このようにして形成される単層型の感光層の膜厚は、５〜１００μｍ程度が適当である。
【００４５】
また、感光層の上に必要に応じて膜厚０．５〜１０μｍの保護層を形成しても良い。保護層は上述の分散粒子を結着樹脂中に含有させたものや、さらに電荷輸送物質を加えたものを用いることができる。
【００４６】
次に、本発明の電子写真装置について説明する。本発明の電子写真プロセスには、帯電手段、露光手段、現像手段、転写手段、分離手段、クリーニング手段などの各手段として、公知のいずれの手段も使用することができる。例えば、帯電手段においてはコロナ帯電方式に代表される非接触帯電方式、帯電ローラー、帯電ブラシなどに代表される接触若しくは近接配置帯電方式のいずれもが使用できる。特に、オゾン発生量が少なく、印加電圧の小さい接触帯電方式は良好に使用される。
【００４７】
帯電ローラーには、シリコーンゴム、ポリウレタンゴム、クロロプレンゴム、イソプレンゴム、ＥＰＤＭゴム、エポキシゴム、ブチルゴム等の帯電部材が用いられる。また帯電ブラシにおいては、レーヨン繊維、カーボン繊維等の導電性ブラシや、導電スリーブとこれに内包されるマグネットロールとこのマグネットロールの磁界により磁気拘束された導電性磁性粒子（導電性磁性キャリア）で構成された磁気ブラシ等が用いられる。
【００４８】
露光手段においては、半導体レーザーを用い、その波長は７８０ｎｍ以下、好ましくは７８０〜５００ｎｍであり、解像度を向上するためにレーザービーム径を絞るなどのものも良好に使用できる。現像手段においては、湿式現像法、乾式現像法のいずれもが良好に使用できる。また、高解像度の画像を得るために、トナー粒径を小さくする、カプセルトナーを用いるなども非常に有用である。転写手段においては、直接紙に転写する手段はもちろんのこと、転写ベルト、転写ドラムなどの中間転写体を用いることも有用である。クリーニング手段として、ブレード法、ブラシ法などの公知の方法を用いることができる。また、転写効率及びクリーニング効率を向上するため、感光体の表面エネルギーを低減させるべく外添剤を感光体表面に具備できる装置を併用することは有用であり、良好に使用される。
【００４９】
【実施例】
以下本発明を実施例によって説明するが、本発明はこれら実施例によって限定されるものではない。
画像形成時に発生する微小黒点と電子写真感光体の関係を調べるため、電子写真感光体を次のような方法で作成した。
【００５０】
（実施例１）
ＥＤ法により作成した外径３０ｍｍ、長さ３４０ｍｍの無切削アルミニウム素管に、白色顔料である平均粒子径０．２５μｍの酸化チタン７０重量部、アルキッド樹脂（ベッコライトＭ６４０１−５０−Ｓ（固形分５０％）：大日本インキ化学工業社製）１５重量部、メラミン樹脂（スーパーベッカミンＬ−１２１−６０（固形分６０％）：大日本インキ化学工業社製）１０重量部、メチルエチルケトン１００重量部からなる混合物をボールミルで７２時間分散して調製した中間層用塗工液を塗布し、１３０℃で２０分間乾燥して、膜厚３μｍの中間層を作成した。
【００５１】
次に下記構造式（IV）に示すトリスアゾ顔料１０重量部を、ポリビニルブチラール（ＢＭ−２：積水化学工業社製）４重量部をシクロヘキサノン１５０重量部に溶解した樹脂液に添加し、ボールミルにて７２時間分散を行った。分散終了後、シクロヘキサノン２１０重量部を加え３時間分散を行い、電荷発生層用塗工液を作成した。これを前記中間層上に塗布し、１３０℃１０分間乾燥して膜厚０．２μｍの電荷発生層を作成した。
【００５２】
次に、下記構造式（Ｖ）に示す化合物７重量部、ポリカーボネート樹脂（ユーピロンＺ２００：三菱ガス化学社製）１０重量部、シリコーンオイル（ＫＦ−５０：信越化学工業社製）０．００２重量部、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₈−、−Ｒ₂が−（ＣＨ₂）₃ＣＨ₃からなる下記構造式（Ｉ−１）の化合物０．０８重量部をテトラヒドロフラン１００重量部に溶解し、電荷輸送層用塗工液を作成した。これを前記電荷発生層上に塗布し、１３０℃２０分間乾燥して平均膜厚２０μｍとなるように電荷輸送層を形成し、電子写真感光体を得た。
【化１４】

【化１５】

【化１６】

【００５３】
（実施例２）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₁₂−、−Ｒ₂が−（ＣＨ₂）₃ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００５４】
（実施例３）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₁₆−、−Ｒ₂が−（ＣＨ₂）₃ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００５５】
（実施例４）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₇（ＣＨ₂）（ＣＨ₂）₇−、−Ｒ₂が−（ＣＨ₂）₃ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００５６】
（実施例５）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₂₀−、−Ｒ₂が−（ＣＨ₂）₃ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００５７】
（実施例６）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₁₆−、−Ｒ₂が−ＣＨ₂ＣＨ（ＣＨ₃）₂からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００５８】
（実施例７）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₁₆−、−Ｒ₂が−ＣＨ₂ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００５９】
（比較例１）
電荷輸送層用塗工液に構造式（Ｉ−１）の化合物を添加しない以外は実施例１と同様に、電子写真感光体を作成した。
【００６０】
（比較例２）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃ＣＨ₂−、−Ｒ₂が−（ＣＨ₂）₃ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００６１】
（比較例３）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₂₆−、−Ｒ₂が−（ＣＨ₂）₃ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００６２】
（比較例４）
電荷輸送層用塗工液を構造式（Ｉ−１）の代わりに、前記一般式（Ｉ）のＲ₁−がＣＨ₃（ＣＨ₂）₈−、−Ｒ₂が−（ＣＨ₂）₉ＣＨ₃からなる化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【００６３】
得られた電子写真感光体を、像露光手段に７８０ｎｍの半導体レーザー及び帯電手段に接触ローラー帯電器を備えた画像形成装置（リコー社製ＩＭＡＧＩＯ ＭＦ−２００）を用い、高温高湿環境下（３０℃９０％）における初期画像評価、及びＡ４用紙３万枚通紙後のハーフトーン及び白紙出力時の画像評価を実施した。その際、潜像作成条件は暗部電位Ｖｄが−９００Ｖとなるように設定した。その結果を表１に示す。表１中、○は良好を示す（以下同じ）。
【００６４】
【表１】

【００６５】
次に、耐ガス性（耐画像ボケ性）の評価を、前記と同様の画像形成装置を用い、複写機周囲のＮＯｘ濃度が８ｐｐｍ環境下において初期画像評価を実施した。その結果を表２に示す。
【００６６】
【表２】

【００６７】
（実施例８）
実施例１と同様にして、アルミニウム素管（導電性支持体）上に中間層、電荷発生層を形成した。続いて、下記構造式（II−１）に示す化合物７重量部、ポリカーボネート樹脂（ユーピロンＺ２００：三菱ガス化学社製）１０重量部、シリコーンオイル（ＫＦ−５０：信越化学工業社製）０．００２重量部、実施例１で用いたのと同じトリスアゾ顔料０．０８重量部をテトラヒドロフラン１００重量部に溶解し、電荷輸送層用塗工液を調製した。これを前記電荷発生層上に塗布し、１３０℃２０分間乾燥して電荷輸送層を形成し、電子写真感光体を得た。電荷輸送層の膜厚は、平均膜厚２８、２４、２０μｍとなるように３種類の感光体を作成した。
【化１７】

【００６８】
（実施例９）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（III−１）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化１８】

【００６９】
（実施例１０）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（II−２）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化１９】

【００７０】
（実施例１１）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（III−２）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２０】

【００７１】
（実施例１２）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（II−３）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２１】

【００７２】
（実施例１３）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（II−４）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２２】

【００７３】
（実施例１４）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（III−３）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２３】

【００７４】
（実施例１５）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（III−４）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２４】

【００７５】
（比較例５）
電荷輸送層用塗工液を構造式（II−２）の代わりに、下記構造式（ａ）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２５】

【００７６】
（比較例６）
電荷輸送層用塗工液を構造式（II−２）の代わりに、下記構造式（ｂ）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２６】

【００７７】
（比較例７）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（ｃ）に示す化合物を用いた以外は実施例１と同様に、電子写真感光体を作成した。
【化２７】

【００７８】
（比較例８）
電荷輸送層用塗工液を構造式（II−１）の代わりに、下記構造式（ｄ）に示す化合物を用いた以外は実施例８と同様に、電子写真感光体を作成した。
【化２８】

得られた電子写真感光体を、像露光手段に７８０ｎｍの半導体レーザー及び帯電手段に接触ローラー帯電器を備えた画像形成装置（リコー社製ＩＭＡＧＩＯ ＭＦ−２００）を用い、高温高湿環境下（３０℃９０％）における初期画像評価、及びＡ４用紙３万枚通紙後のハーフトーン及び白紙出力時の画像評価を実施した。その際、潜像作成条件は暗部電位Ｖｄが−９００Ｖとなるように設定した。その結果を表３に示す。
【００７９】
【表３】

【００８０】
次に、耐ガス性（耐画像ボケ性）の評価を、前記と同様の画像形成装置を用い、複写機周囲のＮＯｘ濃度が８ｐｐｍ環境下において初期画像評価を実施した。その結果を表４に示す。
【００８１】
【表４】

【００８２】
【発明の効果】
以上説明したように、本発明の電子写真感光体及びこれを用いた電子写真装置は、感光層中に特定の化合物を含有させたことにより、感光層及び電荷輸送層の膜厚に依存せず、帯電安定性、繰り返し安定性や耐ガス性が良好であり、長期に渡り微小欠陥等の異常画像発生のない優れたものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member used in an electrophotographic apparatus such as an analog / digital copying machine, a laser printer, or a laser facsimile, and an electrophotographic apparatus using the same.
[0002]
[Prior art]
Conventionally, as a photoconductive material for an electrophotographic photosensitive member, an electrophotographic photosensitive material using an organic photoconductive material having superiority in sensitivity, thermal stability, toxicity, and the like with respect to inorganic materials such as Se, CdS, and ZnO. The development of the body has been actively conducted, and in many copying machines and printers, an electrophotographic photosensitive member using an organic photoconductive material has been mounted.
[0003]
In the electrophotographic photoreceptor using this organic photoconductive material, when a photosensitive layer is formed, a function separation type in which a charge transport layer is laminated on a charge generation layer is generally used because of its excellent sensitivity and durability. Yes. In this type of photoreceptor, the charge transport layer is generally composed of a charge transport material, a binder resin, and optionally several kinds of additives.
[0004]
However, with recent digitalization of copying machines and printers and higher image quality, abnormal images due to minute defects such as black spots, white spots, and background stains tend to appear noticeably. Furthermore, with repeated use, the photosensitive layer thickness gradually decreases due to wear, and the charge transport layer is required to be thin in order to achieve high image quality. There is an increasing demand for electrophotographic photoreceptors.
[0005]
As a method for obtaining an electrophotographic photosensitive member having high charging stability with respect to these problems, conventionally, an intermediate layer is provided between the photosensitive layer and the support to suppress a decrease in charging potential or dark portion potential. Proposed. Examples of such an intermediate layer include polyamides (described in JP-A-46-47344 and JP-A-52-25638), polyesters (described in JP-A-52-20836 and JP-A-54-26738). ), Polyurethane (described in JP-A-49-10044, JP-A-53-89435), casein (described in JP-A-55-1035556), polyvinyl alcohol (described in JP-A-52-100240) , Polyvinylpyrrolidone (described in JP-A-48-30936), polyvinyl butyral (described in JP-A-57-90639, JP-A-58-106549), vinyl acetate-ethylene copolymer (JP-A-48). -261141), ethyl cellulose (described in JP-A-55-143564), N-methoxymethylated sodium Ron has been known to use (JP-A-2-108064 JP) resin or the like. However, the electrophotographic photoreceptor using the intermediate layer of these materials has a problem that the residual potential is increased although the decrease in the charging potential is reduced, and the charging potential is decreased although the residual potential is not increased. There is a problem that the variation in electrostatic characteristics due to the environment becomes large, and providing an intermediate layer still does not provide a sufficient one.
[0006]
Regarding prevention of residual potential due to repeated use, a sulfonic acid ester compound and an aromatic carboxylic acid metal complex or metal salt (Japanese Patent No. 2953124) or an aliphatic ester compound (Japanese Patent Laid-Open No. 8-320581) are used in the photosensitive layer. ) Is proposed. However, these compounds have a problem that the effect on the increase of the residual potential is low, and abnormal images such as minute black spots are generated as the photosensitive layer becomes thinner.
[0007]
Regarding the improvement of gas resistance, as shown in JP-A-57-122444, JP-A-63-18355, etc., antioxidants (hindered phenol compounds, phosphorus compounds, sulfur compounds, amines) It has been proposed to add a compound, a hindered amine compound, etc.) to the photosensitive layer. However, these antioxidants have a problem that the effect on gas resistance is low, and even if effective, other properties (sensitivity, residual potential, etc.) are significantly deteriorated. Nothing has been obtained.
[0008]
Further, regarding printing durability by repeated use, as disclosed in JP-A-11-202535, it has been proposed to add a wax having an ester group to the photosensitive layer. However, these waxes have problems such as low gas resistance and sufficient durability, but other properties (sensitivity, residual potential, etc.) are significantly deteriorated and are still satisfactory. No electrophotographic photoreceptor has been obtained.
[0009]
As described above, an electrophotographic photosensitive member excellent in charging stability, repetitive stability and gas resistance and free from abnormal images such as minute defects and image blurring when used in a high-quality digital copying machine or printer has not been obtained. is the current situation.
[0010]
[Problems to be solved by the invention]
The object of the present invention is to solve the above-mentioned conventional problems, and is excellent in charging stability, repetitive stability and gas resistance without depending on the film thickness of the photosensitive layer and the charge transport layer. It is an object of the present invention to provide an electrophotographic photosensitive member that does not generate abnormal images such as the above, and an electrophotographic apparatus using the same.
[0011]
[Means for Solving the Invention]
The present inventor is effective in improving the charging stability, repetitive stability, and gas resistance, which are the conventional problems described above, by the compounds represented by the following general formulas (I), (II) and (III). As a result of diligent studies, the present invention was completed in order to find out a certain fact and use it for an electrophotographic photosensitive member.
[0012]
[Chemical 6]

(In the formula, R ₁₁ represents a linear, branched, saturated or unsaturated aliphatic hydrocarbon group having 8 to 25 carbon atoms, and R ₁₂ may be either a straight or branched chain having 4 or less carbon atoms. Represents a hydrocarbon group.)
[0013]
[Chemical 7]

(Wherein R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ are each independently a hydrogen atom, a halogen atom, a hydroxy group, a straight chain having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, branched, saturated or An alkyl group or an alkoxy group which may be any unsaturated is represented, and R ₂₆ represents a linear, branched, saturated or unsaturated alkyl group having 8 to 25 carbon atoms.
[0014]
[Chemical 8]

(Wherein R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ and R ₃₅ are each independently a hydrogen atom, a halogen atom, a hydroxy group, a straight chain, branched, saturated or 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms. An alkyl group or an alkoxy group which may be any unsaturated is represented, and R ₃₆ represents a linear, branched, saturated or unsaturated alkyl group having 8 to 25 carbon atoms.
[0015]
Therefore, according to the present invention, in an electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, at least one of the compounds represented by the following general formulas (I), (II) and (III) in the photosensitive layer. An electrophotographic photoreceptor characterized in that it contains seeds is provided.
[Chemical 9]

(In the formula, R ₁₁ represents a linear, branched, saturated or unsaturated aliphatic hydrocarbon group having 8 to 25 carbon atoms, and R ₁₂ may be either a straight or branched chain having 4 or less carbon atoms. Represents a hydrocarbon group.)
[Chemical Formula 10]

(In the formula, R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ are each independently a hydrogen atom, a halogen atom, a hydroxy group, a linear, branched or saturated group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms. Or an alkyl group or an alkoxy group which may be unsaturated, and R ₂₆ represents a linear, branched, saturated or unsaturated alkyl group having 8 to 25 carbon atoms.
Embedded image

(Wherein R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ and R ₃₅ are each independently a hydrogen atom, a halogen atom, a hydroxy group, a linear, branched or saturated group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms. Or an alkyl group or an alkoxy group which may be unsaturated, and R ₃₆ represents an alkyl group which may have a straight chain, branched, saturated or unsaturated group having 8 to 25 carbon atoms.
[0016]
According to the present invention, there is provided an electrophotographic apparatus using the above-described electrophotographic photosensitive member in an electrophotographic apparatus that prepares a latent image by charging means and forms a latent image by subsequent image exposure. Provided.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
Specific examples of the compound represented by the general formula (I) include methyl laurate, ethyl laurate, isopropyl laurate, n-butyl laurate, isobutyl laurate, methyl palmitate, ethyl palmitate, isopropyl palmitate. , N-butyl palmitate, isobutyl palmitate, methyl stearate, ethyl stearate, n-butyl stearate, isobutyl stearate, methyl oleate, ethyl oleate, n-butyl oleate and the like.
[0018]
Specific examples of the compound represented by the general formula (II) include lauryl benzoate, palmityl benzoate, stearyl benzoate, oleyl benzoate, lauryl salicylate, palmityl salicylate, stearyl salicylate, oleyl salicylate. Lauryl o-anisate, palmityl m-anisate, stearyl o-anisate, oleyl p-anisate, lauryl o-toluate, palmityl m-toluate, stearyl o-toluate, oleyl p-toluate, 2-chlorobenzoic acid lauryl ester, 3 -Chlorobenzoic acid palmityl ester, 2-chlorobenzoic acid stearyl ester, 4-chlorobenzoic acid oleyl ester and the like.
[0019]
Specific examples of such compounds represented by the general formula (III) include phenyl laurate, phenyl palmitate, phenyl stearate, phenyl oleate, lauric acid-2-hydroxy-phenyl, palmitic acid-3- Hydroxy-phenyl, stearic acid-2-hydroxy-phenyl, oleic acid-4-hydroxy-phenyl, lauric acid-2-methoxy-phenyl, palmitic acid-3-methoxy-phenyl, stearic acid-2-methoxy-phenyl, olein Acid-4-methoxy-phenyl, lauric acid-2-methyl-phenyl, palmitic acid-3-methyl-phenyl, stearic acid-2-methyl-phenyl, oleic acid-4-methyl-phenyl, lauric acid-2-chloro -Phenyl, palmitic acid-3-chloro-phenyl Stearic acid-2-chloro - phenyl, oleic acid 4-chloro - phenyl, and the like.
[0020]
Further, according to the present invention, among the compounds represented by the general formula (II) and the general formula (III), it is effective to use the compounds represented by the following general formula (IIa) and the general formula (IIIa). And more preferable.
Embedded image

(In the formula, R ₂₁ represents a hydrogen atom, a halogen atom, a hydroxy group, a linear, branched, saturated or unsaturated alkyl group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, or an alkoxy group. ₂₆ 'represents a linear, branched, saturated or unsaturated alkyl group having 12 to 22 carbon atoms.
Embedded image

(In the formula, R ₃₁ represents a hydrogen atom, a halogen atom, a hydroxy group, a linear or branched, saturated or unsaturated alkyl group or alkoxy group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, and the like. ₃₆ 'represents a linear, branched, saturated or unsaturated alkyl group having 12 to 22 carbon atoms.
[0021]
In the general formulas (II), (IIa), (III), and (IIIa) of the present invention, R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , R ₃₁ , R ₃₂ , R ₃₃ , The alkyl group for R ₃₄ and R ₃₅ is preferably a lower alkyl group having 1 to 6 carbon atoms, particularly preferably a methyl group or an ethyl group. Moreover, as an alkoxy group, a methoxy group, an ethoxy group, etc. are preferable. In the formula, the alkyl group of R ₂₆ ′ and R ₃₆ ′ may be linear, branched, saturated, or unsaturated, but is preferably linear.
[0022]
Furthermore, according to the present invention, at least one added amount of the compounds represented by the general formulas (I), (II), (IIa), (III), and (IIIa) is a binder contained in the photosensitive layer or the charge transport layer. It is more preferable from the point of an effect that it is 0.1-20 weight part with respect to 100 weight part of resin. If the addition amount is less than the above range, the effect on the charging stability and gas resistance is small, and if it is more than the above range, the residual potential during repeated use tends to increase.
[0023]
In the present invention, by including any of the compounds of the general formulas (I), (II), (IIa), (III), and (IIIa) in the photosensitive layer and the charge transporting layer, gas resistance and electrostatic durability are extremely high. The reason for the improvement is not clear, but since the structure of the compound includes both long and short chains, the compatibility in the photosensitive layer and the charge transport layer is high, and the compound easily enters the voids and has gas permeability. It is thought that it can be reduced. Further, it is considered that the polarity in the compound due to the difference in chain length plays a role of preventing the movement of thermally excited carriers in the photosensitive layer and the charge transport layer.
[0024]
As a means for achieving high image quality, there is a method in which the charge transport layer is made into a thin film to reduce diffusion during charge transfer. However, as the film becomes thin, the amount of gas permeation increases and the electric field strength of the photosensitive layer increases. Since it becomes high, the effect of charge stability, repeat stability, and gas resistance becomes more remarkable by containing the compound of the present invention. Furthermore, even when the photosensitive layer is scraped with repeated use by high-quality digital copiers and printers, for the same reason as described above, the inclusion of the compound has the effect of charging stability, repeated stability and gas resistance. Becomes more prominent.
[0025]
Examples of the conductive support for an electrophotographic photosensitive member used in the present invention include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum. Metal oxides such as tin oxide, indium oxide, and the like, and film or cylindrical plastic, paper coated with aluminum oxide such as JIS3003, JIS5000, JIS6000, etc. by vapor deposition or sputtering, Those formed into a tubular shape by a general method such as the EI method, ED method, DI method, and II method, and those subjected to surface cutting processing, polishing, anodizing treatment, etc. with a diamond bite can be used. . Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.
[0026]
The photosensitive layer formed on the support is formed by laminating a single layer type photosensitive layer having both a charge generation function and a charge transport function, a charge generation layer containing a charge generation material, and a charge transport layer containing a charge transport material. Any of the laminated type photosensitive layers may be used. Further, an intermediate layer may be provided between the support and the photosensitive layer for the purpose of preventing charge injection from the support onto the photosensitive layer and preventing interference fringes.
[0027]
The structure of the intermediate layer is a binder resin or a dispersion of particles in a binder resin. As the binder resin, thermoplastic resins such as polyvinyl alcohol, nitrocellulose, polyamide, polyvinyl chloride, polyurethane, alkyd- A thermosetting resin such as a melamine resin can be used. As particles to be dispersed in the intermediate layer, titanium oxide, aluminum oxide, tin oxide, zinc oxide, zirconium oxide, magnesium oxide, silica and their surface treatment products are used, and titanium oxide is more preferable in terms of dispersibility and electrical characteristics. Both rutile and anatase types can be used.
[0028]
In order to form the intermediate layer in the present invention, for example, the above-described binder resin is dissolved in an organic solvent, and the above-mentioned particles are dispersed in the solution by means of a ball mill, a sand mill, or the like, applied onto a support, and dried. Just do it. The thickness of the intermediate layer is 10 μm or less, preferably 0.1 to 6 μm.
[0029]
The charge generation layer is a layer mainly composed of a charge generation material, and a binder resin is used as necessary.
As the charge generation substance, either an inorganic material or an organic material can be used. Examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium compounds such as selenium-arsenic, amorphous silicon, and the like. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms or phosphorus atoms are preferably used.
[0030]
On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, methine square silicate pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Jigoido based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.
[0031]
As binder resins used as necessary, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, etc. Is mentioned. These binder resins can be used alone or as a mixture of two or more. In addition, a charge transport material may be added to the charge generation layer as necessary.
[0032]
The method for forming the charge generation layer can be broadly classified into a vacuum thin film preparation method and a casting method from a solution dispersion system. Examples of vacuum thin film preparation methods include vacuum deposition, glow discharge decomposition, ion plating, sputtering, reactive sputtering, and CVD. Charge generation using the inorganic or organic materials described above. A layer can be formed satisfactorily. In order to form the charge generation layer by the casting method, the above-described inorganic or organic charge generation material is used together with a binder resin, if necessary, with a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone, ball mill, atom or the like. What is necessary is just to disperse | distribute with a lighter, a sand mill, etc., apply | coat and dry a dispersion liquid moderately. As a coating method, a dip coating method, a spray coating method, a bead coating method, or the like can be used.
[0033]
The film thickness of the charge generation layer thus formed is suitably about 0.01 to 5 μm, particularly preferably 0.05 to 2 μm.
[0034]
The charge transport layer is a layer mainly composed of a charge transport material, and is composed of the charge transport material, the binder resin, and the compound represented by the general formula (I) (II) (IIa) (III) (IIIa) shown in the present invention. It can be formed by dissolving or dispersing at least one kind in an appropriate solvent such as tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, cyclohexanone, and applying and drying the solution or dispersion. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added to a charge transport layer as needed.
[0035]
Charge transport materials include hole transport materials and electron transport materials.
[0036]
Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4, 8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, 3, Well-known electron accepting substances such as 5-dimethyl-3 ', 5'-ditertiary butyl-4,4'-diphenoquinone can be mentioned. These electron transport materials can be used alone or as a mixture of two or more.
[0037]
Moreover, as a hole transport material, an oxazole derivative, an oxadiazole derivative, an imidazole derivative, a triphenylamine derivative, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane , Styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, etc., and these hole transport materials Can be used alone or as a mixture of two or more.
[0038]
The binder resin used for the charge transport layer includes polycarbonate (bisphenol A type, bisphenol Z type, etc.), polyester, methacrylic resin, acrylic resin, polyethylene, vinyl chloride, vinyl acetate, polystyrene, phenolic resin. , Epoxy resin, polyurethane, polyvinylidene chloride, alkyd resin, silicon resin, polyvinyl carbazole, polyvinyl butyral, polyvinyl formal, polyacrylate, polyacrylamide, phenoxy resin, and the like. These binder resins can be used alone or as a mixture of two or more. The amount of the binder resin used is suitably 0 to 150 parts by weight with respect to 100 parts by weight of the charge transport material.
[0039]
As the binder resin, a polymer charge transport material having a function as a binder resin and a function as a charge transport material can also be used. Examples of such a polymer charge transport material include (a) a polymer having a carbazole ring in the main chain and / or side chain, such as poly-N-vinylcarbazole, JP-A-50-82056, Examples thereof include compounds described in JP-A-54-9632, JP-A-54-11737, and JP-A-4-183719. (B) Polymers having a hydrazone structure in the main chain and / or side chain, for example, compounds described in JP-A-57-78402 and JP-A-3-50555 can be exemplified. (C) Polysilylene polymers, for example, compounds described in JP-A-63-285552, JP-A-5-19497, and JP-A-5-70595 can be exemplified. (D) A polymer having a tertiary amine structure in the main chain and / or side chain, such as N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-1-13061, JP-A-1-19049, JP-A-1-1728, JP-A-1-105260, JP-A-2-167335, JP-A-5-66598, JP-A-5-40350, etc. Can be illustrated.
The thickness of the charge transport layer formed in this manner is suitably about 5 to 100 μm.
[0040]
As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 1 weight with respect to the binder resin. Part is appropriate.
[0041]
Antioxidants such as hindered phenol compounds, sulfur compounds, phosphorus compounds, hindered amine compounds, pyridine derivatives, piperidine derivatives, morpholine derivatives can be used as the antioxidant, and the amount used is 100 weight of binder resin. About 0 to 5 parts by weight per part is appropriate.
[0042]
The single layer type photoreceptor includes a charge generation material, a charge transport material, a binder resin, and at least one compound of the general formulas (I), (II), (IIa), (III), and (IIIa) shown in the present invention. Consists of. As the charge generation material and the charge transport material, the above materials can be used.
[0043]
In order to form such a single-layer type photosensitive layer, a charge generating substance, a charge transporting substance and a binder resin are mixed with a suitable solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone, a ball mill, an attritor, What is necessary is just to melt | dissolve thru | or disperse | distribute with a sand mill etc., this should be diluted moderately, and to apply | coat and dry. The coating can be performed using a dip coating method, a spray coating method, a bead coating method, or the like. As the binder resin, the binder resin exemplified as the binder resin of the charge transport layer can be used as it is, or it may be used by mixing with the binder resin exemplified as the binder resin of the charge generation layer. If necessary, a plasticizer, a leveling agent, an antioxidant or the like can be added to the single-layer type photosensitive layer. In addition, a single-layer type photosensitive layer in which a charge transport material is added to a eutectic complex formed from a pyrylium dye and a bisphenol A type polycarbonate can also be formed by a coating method similar to the above using an appropriate solvent. .
[0044]
The thickness of the single-layer type photosensitive layer formed in this manner is suitably about 5 to 100 μm.
[0045]
Moreover, you may form a protective layer with a film thickness of 0.5-10 micrometers as needed on a photosensitive layer. As the protective layer, those obtained by incorporating the above-described dispersed particles in a binder resin or those added with a charge transport material can be used.
[0046]
Next, the electrophotographic apparatus of the present invention will be described. In the electrophotographic process of the present invention, any known means can be used as each means such as charging means, exposure means, developing means, transfer means, separation means, and cleaning means. For example, as the charging means, any of a non-contact charging method typified by a corona charging method, a contact or a proximity charging method typified by a charging roller, a charging brush, and the like can be used. In particular, a contact charging method with a small amount of ozone generation and a small applied voltage is used favorably.
[0047]
For the charging roller, charging members such as silicone rubber, polyurethane rubber, chloroprene rubber, isoprene rubber, EPDM rubber, epoxy rubber, and butyl rubber are used. In the charging brush, a conductive brush such as rayon fiber or carbon fiber, a conductive sleeve, a magnet roll included therein, and conductive magnetic particles (conductive magnetic carrier) magnetically constrained by the magnetic field of the magnet roll are used. A configured magnetic brush or the like is used.
[0048]
In the exposure means, a semiconductor laser is used, and the wavelength thereof is 780 nm or less, preferably 780 to 500 nm. In order to improve the resolution, a laser beam diameter can be favorably used. As the developing means, either a wet development method or a dry development method can be used satisfactorily. In addition, in order to obtain a high-resolution image, it is very useful to reduce the toner particle size or use a capsule toner. In the transfer means, it is useful to use an intermediate transfer body such as a transfer belt and a transfer drum, as well as means for transferring directly to paper. As a cleaning means, a known method such as a blade method or a brush method can be used. In order to improve transfer efficiency and cleaning efficiency, it is useful to use an apparatus that can be provided with an external additive on the surface of the photoreceptor so as to reduce the surface energy of the photoreceptor, and it is used favorably.
[0049]
【Example】
EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
In order to investigate the relationship between the minute black spots generated during image formation and the electrophotographic photosensitive member, an electrophotographic photosensitive member was prepared by the following method.
[0050]
(Example 1)
An uncut aluminum base tube having an outer diameter of 30 mm and a length of 340 mm prepared by the ED method, 70 parts by weight of titanium oxide having an average particle diameter of 0.25 μm as a white pigment, an alkyd resin (Beckolite M6401-50-S (solid content 50%): 15 parts by weight of Dainippon Ink and Chemicals), melamine resin (Super Becamine L-121-60 (solid content 60%): 10 parts by weight of Dainippon Ink and Chemicals), 100 parts by weight of methyl ethyl ketone An intermediate layer coating solution prepared by dispersing the mixture consisting of 72 hours with a ball mill was applied and dried at 130 ° C. for 20 minutes to form an intermediate layer having a thickness of 3 μm.
[0051]
Next, 10 parts by weight of a trisazo pigment represented by the following structural formula (IV) was added to a resin solution in which 4 parts by weight of polyvinyl butyral (BM-2: manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 150 parts by weight of cyclohexanone, and Dispersion was performed for 72 hours. After the completion of dispersion, 210 parts by weight of cyclohexanone was added and dispersed for 3 hours to prepare a charge generation layer coating solution. This was coated on the intermediate layer and dried at 130 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.
[0052]
Next, 7 parts by weight of a compound represented by the following structural formula (V), 10 parts by weight of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company), 0.002 parts by weight of silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) In the general formula (I), R ₁ — is CH ₃ (CH ₂ ) ₈ —, and —R ₂ is — (CH ₂ ) ₃ CH _3. Was dissolved in 100 parts by weight of tetrahydrofuran to prepare a charge transport layer coating solution. This was applied onto the charge generation layer and dried at 130 ° C. for 20 minutes to form a charge transport layer having an average film thickness of 20 μm, thereby obtaining an electrophotographic photosensitive member.
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[0053]
(Example 2)
Instead of the structural formula (I-1), the charge transporting layer coating solution is replaced with R ₁ — in the general formula (I) is CH ₃ (CH ₂ ) ₁₂ —, and —R ₂ is — (CH ₂ ) ₃ CH. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound consisting of ₃ was used.
[0054]
(Example 3)
Instead of the structural formula (I-1), the charge transport layer coating solution is substituted by R _{1-in the} general formula (I) is CH ₃ (CH ₂ ) _16- , -R ₂ is-(CH ₂ ) ₃ CH An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound consisting of ₃ was used.
[0055]
Example 4
Instead of the structural formula (I-1), R ₁ − in the general formula (I) is CH ₃ (CH ₂ ) ₇ (CH ₂ ) (CH ₂ ) ₇ —, —R An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that a compound in which ₂ was — (CH ₂ ) ₃ CH ₃ was used.
[0056]
(Example 5)
Instead of the structural formula (I-1), the charge transport layer coating solution is substituted by R _{1-in the} general formula (I) is CH ₃ (CH ₂ ) ₂₀ -and -R ₂ is-(CH ₂ ) ₃ CH. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound consisting of ₃ was used.
[0057]
(Example 6)
In the charge transport layer coating solution, R ₁ — in the general formula (I) is CH ₃ (CH ₂ ) ₁₆ —, and —R ₂ is —CH ₂ CH (CH ₃ ) instead of the structural formula (I-1). ) An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the compound consisting of ₂ was used.
[0058]
(Example 7)
In the charge transport layer coating solution, R ₁ — in the general formula (I) is CH ₃ (CH ₂ ) ₁₆ — and —R ₂ is —CH ₂ CH ₃ instead of the structural formula (I-1). An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the compound was used.
[0059]
(Comparative Example 1)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound of the structural formula (I-1) was not added to the charge transport layer coating solution.
[0060]
(Comparative Example 2)
In the charge transport layer coating liquid, instead of the structural formula (I-1), R ₁ — in the general formula (I) is CH ₃ CH ₂ —, and —R ₂ is — (CH ₂ ) ₃ CH _3. An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the compound was used.
[0061]
(Comparative Example 3)
Instead of the structural formula (I-1), the charge transport layer coating solution is substituted by R _{1-in the} general formula (I) is CH ₃ (CH ₂ ) ₂₆ -and -R ₂ is-(CH ₂ ) ₃ CH. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound consisting of ₃ was used.
[0062]
(Comparative Example 4)
Instead of the structural formula (I-1), the charge transporting layer coating solution is R ₁ — in the general formula (I) is CH ₃ (CH ₂ ) ₈ —, and —R ₂ is — (CH ₂ ) ₉ CH. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound consisting of ₃ was used.
[0063]
The obtained electrophotographic photosensitive member was subjected to a high-temperature and high-humidity environment using an image forming apparatus (IMAGIO MF-200 manufactured by Ricoh Co., Ltd.) having a 780 nm semiconductor laser as an image exposure means and a contact roller charger as a charging means (30 Initial image evaluation at 90 ° C.), and image evaluation at the time of halftone and blank paper output after passing 30,000 sheets of A4 paper. At that time, the latent image creation conditions were set such that the dark portion potential Vd was −900V. The results are shown in Table 1. In Table 1, o indicates good (the same applies hereinafter).
[0064]
[Table 1]

[0065]
Next, evaluation of gas resistance (image blur resistance) was performed using an image forming apparatus similar to the above, and initial image evaluation was performed in an environment where the NOx concentration around the copier was 8 ppm. The results are shown in Table 2.
[0066]
[Table 2]

[0067]
(Example 8)
In the same manner as in Example 1, an intermediate layer and a charge generation layer were formed on an aluminum base tube (conductive support). Subsequently, 7 parts by weight of a compound represented by the following structural formula (II-1), 10 parts by weight of a polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company), silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002 A charge transport layer coating solution was prepared by dissolving 0.08 part by weight of the same trisazo pigment used in Example 1 in 100 parts by weight of tetrahydrofuran. This was applied onto the charge generation layer and dried at 130 ° C. for 20 minutes to form a charge transport layer, whereby an electrophotographic photoreceptor was obtained. Three types of photoconductors were prepared so that the charge transport layer had an average film thickness of 28, 24, and 20 μm.
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[0068]
Example 9
An electrophotographic photosensitive member was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (III-1) instead of the structural formula (II-1).
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[0069]
(Example 10)
An electrophotographic photosensitive member was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (II-2) instead of the structural formula (II-1).
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[0070]
(Example 11)
An electrophotographic photoreceptor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (III-2) instead of the structural formula (II-1).
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[0071]
(Example 12)
An electrophotographic photoreceptor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (II-3) instead of the structural formula (II-1).
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[0072]
(Example 13)
An electrophotographic photoreceptor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (II-4) instead of the structural formula (II-1).
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[0073]
(Example 14)
An electrophotographic photosensitive member was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (III-3) instead of the structural formula (II-1).
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[0074]
(Example 15)
An electrophotographic photoreceptor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (III-4) instead of the structural formula (II-1).
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[0075]
(Comparative Example 5)
An electrophotographic photoreceptor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (a) instead of the structural formula (II-2).
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[0076]
(Comparative Example 6)
An electrophotographic photoreceptor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (b) instead of the structural formula (II-2).
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[0077]
(Comparative Example 7)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (c) instead of the structural formula (II-1).
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[0078]
(Comparative Example 8)
An electrophotographic photoreceptor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution was replaced with the compound represented by the following structural formula (d) instead of the structural formula (II-1).
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The obtained electrophotographic photosensitive member was subjected to a high-temperature and high-humidity environment using an image forming apparatus (IMAGIO MF-200 manufactured by Ricoh Co., Ltd.) having a 780 nm semiconductor laser as an image exposure means and a contact roller charger as a charging means (30 Initial image evaluation at 90 ° C.), and image evaluation at the time of halftone and blank paper output after passing 30,000 sheets of A4 paper. At that time, the latent image creation conditions were set such that the dark portion potential Vd was −900V. The results are shown in Table 3.
[0079]
[Table 3]

[0080]
Next, evaluation of gas resistance (image blur resistance) was performed using an image forming apparatus similar to the above, and initial image evaluation was performed in an environment where the NOx concentration around the copier was 8 ppm. The results are shown in Table 4.
[0081]
[Table 4]

[0082]
【The invention's effect】
As described above, the electrophotographic photosensitive member of the present invention and the electrophotographic apparatus using the same do not depend on the film thickness of the photosensitive layer and the charge transport layer by including a specific compound in the photosensitive layer. They are excellent in charging stability, repetitive stability and gas resistance, and are free of abnormal images such as micro defects over a long period of time.

Claims (6)

An electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains at least one compound represented by the following general formula ( IIa ) .

(In the formula, each R ₂₁ independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 8 carbon atoms or an alkoxy group, and R ₂₆ ′ represents an alkyl group having 12 to 22 carbon atoms. .) An electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains at least one compound represented by the following general formula ( IIIa ) .

(In the formula, each R ₃₁ independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 8 carbon atoms or an alkoxy group, and R ₃₆ ′ represents an alkyl group having 12 to 22 carbon atoms. .) The content of at least one compound represented by the general formulas ( IIa ) and ( IIIa ) is 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin contained in the photosensitive layer. The electrophotographic photosensitive member according to claim 1 . Photosensitive layer of at least a charge generating layer, and a charge transport layer, claim 1, said charge transport layer in the general formula (IIa), characterized by comprising been contained in one of the compound of formula (IIIa) The electrophotographic photosensitive member according to any one of -2 . The content of at least one compound represented by the general formulas ( IIa ) and ( IIIa ) is 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin contained in the charge transport layer. 5. The electrophotographic photosensitive member according to claim 4, wherein An electrophotographic apparatus using the electrophotographic photosensitive member according to any one of claims 1 to 5 in an electrophotographic apparatus which prepares a latent image by charging means and forms a latent image by subsequent image exposure. .