JP3960580B2 - Electrophotographic photosensitive member and image forming apparatus using the same - Google Patents

Description

【表２】

特に、下記一般式（１）
【化３】

（式中、Ｍはアルカリ金属、Ｒ_１及びＲ_２は水素又は炭素数４〜２０のアルキル基、ｍ及びｎは２〜１０の整数を示す）で表されるポリオキシエチレンアルキルエーテルリン酸塩が、静電気的副作用が少なくため好ましく用いられる。中でも、Ｒ_１〜Ｒ_２が炭素数１２〜１５のアルキル基、ｍ、ｎが２〜８の整数であるポリオキシエチレンアルキルエーテルリン酸は特に好ましい界面活性剤である。また、下記一般式（２）
【化４】

（式中、Ｒ_１、Ｒ_２及びＲ_３は水素又は炭素数４〜２０のアルキル基、ｌ、ｍ及びｎは２〜１０の整数を示す）で表されるポリオキシエチレンアルキルエーテルリン酸塩も、静電気的副作用が少なくため好ましく用いられる。中でもＲ_１、Ｒ_２、Ｒ_３が炭素数１２〜１５のアルキル基、ｌ、ｍ、ｎが２〜８の整数であるポリオキシエチレンアルキルエーテルリン酸は特に好ましい界面活性剤である。
【００１０】
樹脂中間層２ｂに含有される界面活性剤の量は、通常は、重量基準で樹脂１００部に対して１〜２００部、好ましくは、１０〜１００部である。
界面活性剤の含有量が、１部未満では、発生した電荷が樹脂中間層を円滑に移動しないことがあり、２００部を越えると、樹脂との相溶性が悪化したり、暗減衰を生じることがあるので望ましくない。
【００１１】
本発明は、導電性基体１上に、無機顔料を配合した熱硬化性樹脂からなる下引層２ａ、樹脂中間層２ｂ及び感光層３を積層してなる電子写真感光体である。
感光層は、上記のとおり、通常、感光層３を形成する電荷発生層３ａ及び電荷輸送層３bから形成される。
また、単層型、機能分離型のいずれにも適用されるものである。
電荷発生層３ａは、電荷発生物質を主成分とする層で、必要に応じてバインダー樹脂を用いてもよい。
電荷発生物質としては、無機系材料又は有機系材料を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−ヒ素化合物や、アモルファス・シリコン等が挙げられる。
アモルファス・シリコンにあっては、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好ましく用いられる。
有機系材料としては、公知の材料を用いることができる。
例えば、金属フタロン、無金属フタロシアニン等のフタロシアニン系顔料、アズレニシアニウム塩顔料、スクエアリック酸メチン顔料、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、アントラキノン系又は多環キノン系顔料、キノンイミン系顔料、ジフェニルメタン又はトリフェニルメタン系顔料、ベンゾキノン又はナフトキノン系顔料、シアニン又はアゾメチン系顔料、インジゴイド系顔料、ビスベンズイミダゾール系顔料等を挙げることができる。
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。
必要に応じて用いられるバインダー樹脂としては、ポリアミド樹脂、ポリウレタン樹脂、エポキシ樹脂、ポリケトン樹脂、ポリカーボネート樹脂、シリコーン樹脂、アクリル樹脂、ポリビニルブチラール樹脂、ポリビニルホルマール樹脂、ポリビニルケトン樹脂、ポリスチレン樹脂、ポリ−Ｎ−ビニルカルバゾール樹脂、ポリアクリルアミド樹脂等が挙げられる。
これらのバインダー樹脂は、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、必要に応じて、下記の電荷輸送物質を添加してもよい。
バインダー樹脂を用いる場合、バインダー樹脂の量は、重量基準で電荷発生物質１００部に対し、１０〜５００部、好ましくは、２５〜３００部である。
【００１２】
電荷発生層３ａを形成する方法は、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に大別される。
前者の方法には、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（化学蒸着）法等がある。
後者のキャスティング法によって電荷発生層３ａを形成するときは、上記電荷発生物質を必要によりバインダー樹脂と共に、テトラヒドロフラン、シクロヘキン、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、アサノトライター、サンドミル等により分散し、分散液を適度に希釈して塗布することにより形成できる。
塗布は、浸漬塗工法やスプレーコート、ビードコート法などを用いて行なうことができる。
このようにして形成された電荷発生層の層の厚さは、０．０１〜５μｍ程度が適当であり、好ましくは、０．０５〜２μｍである。
【００１３】
電荷輸送層３bは、電荷輸送物質及びバインダー樹脂を、適当な溶剤に溶解又は分散し、これを塗布、乾燥することにより形成される。
また、必要により可塑剤やレベリング剤を添加することもできる。
電荷輸送物質としては、例えば、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、チオフェン誘導体等が挙げられる。
これらの電荷輸送物質は、単独又は２種以上の混合物として用いることができる。
電荷輸送層に用いられるバインダー樹脂としては、ポリカーボネート樹脂（ビスフェノールＡタイプ、ビスフェノールＺタイプ）、ポリエステル樹脂、メタクリル樹脂、アクリル樹脂、ポリエチレン樹脂、塩化ビニル樹脂、酢酸ビニル樹脂、ポリスチレン樹脂、フェノール樹脂、エポキシ樹脂、ポリウレタン樹脂、ポリ塩化ビニリデン樹脂、アルキッド樹脂、シリコン樹脂、ポリビニルカルバゾール樹脂、ポリビニルブチラール樹脂、ポリビニルホルマール樹脂、ポリアクリレート樹脂、ポリアクリルアミド樹脂、フェノキシ樹脂等を挙げることができる。
これらのバインダー樹脂は、単独又は２種以上の混合物として用いることができる。
【００１４】
また、バインダー機能と電荷輸送機能の双方を持つ高分子電荷輸送物質を、バインダー樹脂として用いることもできる。
この場合に用いられる高分子電荷輸送物質の例としては、主鎖及び／又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が挙げられる（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）。
また、主鎖及び／又は側鎖にヒドラゾン構造を有する重合体を挙げることもできる（特開昭５７−７８４０２号公報、特開平３−５０５５５号公報）。
ポリシリレン重合体も使用可能である（特開昭６３−２８５５５２号公報、特開平５−１９４９７号公報、特開平５−７０５９５号公報）。
さらに、主鎖及び／又は側鎖に第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も使用可能である（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）。
その他のものとして、例えば、ニトロピレンのホルムアルデヒド縮重合体をも挙げられる（特開昭５１−７３８８８号公報、特開昭５６−１５０７４９号公報）。
これら高分子電荷輸送物質は、上記のものに限られるものではなく、一般共重合体、ブロック共重合体、グラフト共重合体、スターポリマー、電子供与性基を有する架橋重合体等を用いることも可能である（特開平３−１０９４０６号公報）。
バインダー樹脂と電荷輸送物質との比は、重量基準で通常は、バインダー樹脂１００部に対して電荷輸送物質２０〜３００部、好ましくは、４０〜１５０部である。
【００１５】
本発明においては、電荷輸送層３b中に、可塑剤やレベリング剤を添加してもよい。
可塑剤としては、ジブチルフタレート、ジオクチルフタレート等の一般の樹脂の可塑剤として使用されているものがそのまま使用でき、その使用量は、重量基準でバインダー樹脂に対して０〜３０％程度が適当である。
レベリング剤としては、側鎖にパーフルオロアルキル基を有するポリマー又はオリゴマーが使用され、その使用量は、重量基準でバインダー樹脂に対して０〜１％程度が適当である。
この電荷輸送層の層厚さは、５〜１００μｍ程度である。
【００１６】
次に、感光層が単層構造である場合について説明する。
キャスティング法により単層感光層を形成する場合、多くは電荷発生物質と電荷輸送物質よりなる機能分離型のものが採用される。
この場合、電荷発生物質及び電荷輸送物質としては、上記のものが用いられ、電荷発生物質、電荷輸送物質及びバインダー樹脂を適当な溶剤に溶解又は分散し、これを塗布、乾燥することにより形成できる。
また、必要により可塑剤やレベリング剤を添加することもできる。
バインダー樹脂としては、上記電荷輸送層３bに用いるバインダー樹脂が用いられ、また、電荷発生層３ａに用いるバインダー樹脂混合して用いてもよい。
可塑剤、レベリング剤も上記と同様である。
単層感光層は、電荷発生物質、電荷輸送物質及びバインダー樹脂を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、サンドミル等により分散し、分散液を適度に希釈して塗布することにより、形成できる。
塗布は、浸漬塗工法やスプレーコート、ビードコート法などを用いて行なうことができる。
ピリリウム系染料、ビスフェノールＡ系ポリカーボネート樹脂から形成される共晶錯体に、電荷輸送物質を添加した感光体も、適当な溶媒を用いて同様な塗工法により形成することができる。
単層感光層の層の厚さは、５〜１００μｍ程度が適当である。
【００１７】
また、本発明においては、耐環境性の改善のため、とりわけ、感度低下、残留電位の上昇を防止するために、酸化防止剤を添加することができる。
酸化防止剤は、有機物を含む層ならばいずれに添加してもよいが、電荷輸送物質を含む層に添加することが好ましい。
酸化防止剤としては、２，６−ジ−ｔ−ブチル−ｐ−クレゾール、ブチル化ヒドロキシアニソール、２，６−ジ−ｔ−ブチル−４−エチルフェノール、ステアリル−β−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオネート等のモノフェノール系化合物、２，２'−メチレン−ビス−（４−メチル−６−ｔ−ブチルフェノール）、２，２'−メチレン−ビス−（４−エチル−６−ｔ−ブチルフェノール）、４，４'−チオビス−（３−メチル−６−ｔ−ブチルフェノール）、４，４'−ブチリデンビス−（３−メチル−６−ｔ−ブチルフェノール）等のビスフェノール系化合物、１，１，３−トリス−（２−メチル−４−ヒドロキシ−５−ｔ−ブチルフェニル）ブタン、１，３，５−トリメチル−２，４，６−トリス（３，５−ジ−ｔ−ブチル−４−ヒドロキシベンジル）ベンゼン、テトラキス−［メチレン−３−（３'，５'−ジ−ｔ−ブチル−４'−ヒドロキシフェニル）プロピオネート］メタン、ビス［３，３'−ビス（４'−ヒドロキシ−３'−ｔ−ブチルフェニル）ブチリックアッシド］クリコ−ルエステル、トコフェロール類等の高分子フェノール系化合物、Ｎ−フェニル−Ｎ'−イソプロピル−ｐ−フェニレンジアミン、Ｎ，Ｎ'−ジ−ｓｅｃ−ブチル−ｐ−フェニレンジアミン、Ｎ−フェニル−Ｎ−ｓｅｃ−ブチル−ｐ−フェニレンジアミン、Ｎ，Ｎ'−ジ−イソプロピル−ｐ−フェニレンジアミン、Ｎ，Ｎ'−ジメチル−Ｎ，Ｎ'−ジ−ｔ−ブチル−ｐ−フェニレンジアミン等のパラフェニレンジアミン類、２，５−ジ−ｔ−オクチルハイドロキノン、２，６−ジドデシルハイドロキノン、２−ドデシルハイドロキノン、２−ドデシル−５−クロロハイドロキノン、２−ｔ−オクチル−５−メチルハイドロキノン、２−（２−オクタデセニル）−５−メチルハイドロキノン等のハイドロキノン類、ジラウリル−３，３'−チオジプロピオネート、ジステアリル−３，３'−チオジプロピオネート、ジテトラデシル−３，３'−ジチオジプロピオネート等の有機硫黄化合物類、トリフェニルホスフィン、トリ（ノニルフェニル）ホスフィン、トリ（ジノニルフェニル）ホスフィン、トリクレジルホスフィン、トリ（２，４−ジブチルフェノキシ）ホスフィン等の有機燐化合物類が挙げられる。
これら化合物は、ゴム、プラスチック、油脂類等の酸化防止剤として知られており、市販品を容易に入手できる。
酸化防止剤の添加量は、重量基準で電荷輸送物質１００部に対して通常は、０．１〜１００部、好ましくは、２〜３０部である。
【００１８】
本発明は、導電性基体上に、無機顔料を配合した熱硬化性樹脂からなる下引層、樹脂中間層及び感光層を積層してなる電子写真感光体であって、該樹脂中間層に界面活性剤を含有させたことを特徴とする電子写真感光体を提供すると共に、この電子写真感光体を設けたことを特徴とする画像形成装置を提供する。
画像形成装置自体は、上記電子写真感光体を設けたこと以外には、通常の複写機、プリンター又はファクシミリ等に用いられる画像形成装置を採用することができる。
【００１９】
【実施例】
以下に、実施例を挙げて本発明をさらに詳細に説明するが、本発明はこれら実施例によってなんら限定されるものではない。
なお、以下に「部」とあるのは、重量部である。
【００２０】
参考例１
直径３０ｍｍのアルミニウム製円筒状基体上に、下記組成の下引層用塗工液、樹脂中間層用塗工液、電荷発生層用塗工液、電荷輸送層用塗工液、電荷注入層用塗工液を順次、塗布・乾燥して、約３μｍの下引層、約０．２μｍの樹脂中間層、約０．３μｍの電荷発生層、約２０μｍの電荷輸送層を浸漬塗工によって形成して電子写真感光体を作製した。
〔下引層用塗工液〕
アルキッド樹脂溶液（大日本インキ化学工業
：ベッコライトＭ−６４０１−５０） ３７５部
メラミン樹脂溶液（大日本インキ化学工業
：スーパーベッカミンＧ８２１−６０） ２１０部
二酸化チタン（石原産業
：タイペークＣＲ−ＥＬ） １２５０部
２−ブタノン ７８００部
〔樹脂中間層用塗工液〕
ポリアミド樹脂（東レ：アミランＣＭ８０００） ２部
表１に示す化合物Ｎｏ．２ ２部
ｎ−ブタノール ４０部
メタノール ６０部
〔電荷発生層用塗工液〕
下記構造の電荷発生物質 ５部
【化５】

ポリビニルブチラール（ＵＣＣ：ＸＹＨＬ） ２部
シクロヘキサノン ２００部
テトラヒドロフラン ２００部
〔電荷輸送層用塗工液〕
ビスフェノールＺ型ポリカーボネート １０部
下記構造式の電荷輸送物質 ７部
【化６】

塩化メチレン ９０部
【００２１】
実施例１
樹脂中間層に含まれる化合物を、表２に示す化合物Ｎｏ．１０に代えた以外は参考例１と同様にして電子写真感光体を作製した。
【００２２】
実施例２
樹脂中間層に含まれる化合物を、表２に示す化合物Ｎｏ．１１に代えた以外は参考例１と同様にして電子写真感光体を作製した。
【００２３】
実施例３
樹脂中間層に用いたポリアミド樹脂をオイルフリーアルキッド樹脂（大日本インキ：ベッコライトＭ６４０１−５０）３部とブチルメラミン樹脂（大日本インキ：スーパーベッカミンＧ８２１−３０）２部に代えた以外は実施例１と同様にして電子写真感光体を作製した。
【００２４】
実施例４
樹脂中間層に含まれる化合物を、表２に示す化合物Ｎｏ．１１に代えた以外は実施例３と同様にして電子写真感光体を作製した。
【００２５】
比較例１
樹脂中間層に界面活性剤を含有させなかった以外は、参考例１と同様にして電子写真感光体を作製した。
【００２６】
比較例２
樹脂中間層に界面活性剤を含有させなかった以外は、実施例３と同様にして電子写真感光体を作製した。
【００２７】
実施例５
参考例１、実施例１〜４において作製した電子写真感光体を、市販複写機ｉｍａｇｉｏＭＦ２２００（（株）リコー製）の改造品を用いて５千枚の通紙試験を行った後、実機内における感光体の露光部及び非露光部の表面電位を測定した。結果を表３に示す。
【００２８】
比較例３
比較例１及び２において作製した電子写真感光体について、実施例５と同様にして通紙試験を行った後、実機内における感光体の露光部及び非露光部の表面電位を測定した。結果を表３に示す。
【表３】

表３に示すように、本発明の電子写真感光体は、５千枚の通紙試験後も露光部の表面電位は初期とほとんど変化せず、残留電位を低減している。比較例の界面活性剤を添加していない電子写真感光体は露光部の表面電位が高くなり、残留電位が蓄積した。
【００２９】
【発明の効果】
本発明によれば、長期的に安定した画像を与えることのできる電子写真感光体及びこれを設けた画像形成装置が提供され、複写機、プリンター又はファクシミリ等の画像形成装置の設計、作製分野に寄与するところは多大である。
【図面の簡単な説明】
【図１】本発明に係る一つの電子写真用感光体の模式断面図である。
【図２】図２は、本発明に係る他の電子写真用感光体の模式断面図である。
【図３】図３は、本発明に係るもう一つの他の電子写真用感光体の模式断面図である。
【符号の説明】
１ 導電性基体
２ａ 無機顔料を配合し熱硬化性樹脂からなる下引層
２ｂ 樹脂中間層
３ 感光層
３ａ 感光層３を形成する電荷発生層
３ｂ 感光層３を形成する電荷輸送層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member and an image forming apparatus using the same, and more particularly to an electrophotographic photosensitive member capable of providing a stable image for a long period of time and an image forming apparatus provided with the same.
[0002]
[Prior art]
An electrophotographic photosensitive member used for image formation such as a copying machine, a printer or a facsimile is generally formed by laminating an undercoat layer, a resin intermediate layer and a photosensitive layer on a conductive substrate.
In such an electrophotographic photoreceptor, a resin intermediate layer is provided between the undercoat layer and the photosensitive layer in order to suppress image defects that occur when used for a long period of time. It has been proposed to use a dispersion of titanium oxide coated with antimony (Japanese Patent Laid-Open No. 61-036755).
However, when comprehensively evaluated from the chargeability, sensitivity, and image quality, it did not reach a sufficiently satisfactory level.
Further, it has a photosensitive layer and a resin intermediate layer in which titanium oxide coated with tin oxide containing antimony oxide having a particle size of 0.2 μm or less is dispersed in a binder resin, and the weight ratio of the titanium oxide to the binder resin is 2. An electrophotographic photosensitive member having a charge generation layer of 5: 1 or more and containing oxotitanium phthalocyanine is also known (Japanese Patent Laid-Open No. 7-271072).
However, there is a drawback in that exposure portion potential (VL) fluctuations due to continuous runs are large.
[0003]
Furthermore, an undercoat layer and a photosensitive layer in which a thermosetting resin and an inorganic pigment are dispersed in order to satisfy overall charging properties, sensitivity, and image quality, and to suppress image defects that occur when used for a long period of time. It is also known to provide a resin intermediate layer between them (Japanese Patent Laid-Open No. 9-288367).
However, although the image quality is improved, there is a problem that the fluctuation in the actual machine potential VL due to the continuous run is large.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide an electrophotographic photoreceptor capable of solving such problems and forming a stable image for a long period of time, and an image forming apparatus provided with the same.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have made extensive studies focusing on the resin intermediate layer. As a result, by adding a surfactant to the resin intermediate layer, the generated charges can be smoothly applied to the resin intermediate layer. As a result, it has been found that the residual potential can be significantly suppressed and a stable image can be formed in the long term, and the present invention has been completed based on this knowledge.
That is, according to the present invention, there is provided an electrophotographic photosensitive member in which an undercoat layer made of a thermosetting resin containing an inorganic pigment, a resin intermediate layer, and a photosensitive layer are laminated on a conductive substrate, An electrophotographic photosensitive member characterized by containing a surfactant in the intermediate layer and an image forming apparatus provided with the electrophotographic photosensitive member are provided.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of one electrophotographic photoreceptor according to the present invention.
FIG. 2 is a schematic cross-sectional view of another electrophotographic photoreceptor according to the present invention.
FIG. 3 is a schematic cross-sectional view of another electrophotographic photoreceptor according to the present invention.
Here, 1 is a conductive substrate, 2a is an undercoat layer made of a thermosetting resin containing an inorganic pigment, 2b is a resin intermediate layer, 3 is a photosensitive layer, 3a is a charge generation layer forming the photosensitive layer 3, 3b Indicates a charge transport layer forming the photosensitive layer 3.
The electrophotographic photoreceptor shown in FIG. 2 is of a function separation type, and the electrophotographic photoreceptor shown in FIG. 3 is a charge generation layer of the photoconductive layer 3 in the function separation type electrophotographic photoreceptor. The stacking order of 3a and the charge transport layer 3b is reversed.
If the conductive substrate 1 has the undercoat layer 2a, the resin intermediate layer 2b, and the photosensitive layer 3 made of a thermosetting resin containing at least an inorganic pigment, a layer other than the above layers can be arbitrarily formed. You may combine.
[0007]
Examples of the conductive substrate 1 include a conductor or an insulator subjected to a conductive treatment, for example, a metal such as aluminum, iron, copper, gold, or an alloy thereof, or an insulating substrate such as a polyester resin, a polycarbonate resin, a polyimide resin, or glass. Examples thereof include a metal such as aluminum, silver, and gold, a thin film of a conductive material such as indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ), or a paper subjected to a conductive treatment.
There is no restriction | limiting in particular in the shape of the electroconductive base | substrate 1, Any, such as plate shape, drum shape, or belt shape, may be sufficient.
In the present invention, an undercoat layer 2 a made of a thermosetting resin containing an inorganic pigment is formed on the conductive substrate 1.
Examples of the inorganic pigment include conductive fillers such as titanium oxide, calcium fluoride, calcium oxide, silicon oxide, magnesium oxide, zirconium oxide, aluminum oxide, and zinc oxide.
Examples of the thermosetting resin include a silicone resin, a phenol resin, an epoxy resin, an alkyd resin, a melamine resin, and a urea resin. These resins can be used in combination with a butyral resin.
Among these, a thermosetting resin obtained by thermally polymerizing an oil-free alkyd resin and an amino resin such as a butylmelamine resin is preferable.
Although there is no restriction | limiting in particular in the mixture ratio of an inorganic pigment and a thermosetting resin, Usually, the range of 0.1 / 1-5.0 / 1 is preferable by the volume ratio of an inorganic pigment / thermosetting resin.
The thickness of the undercoat layer 2a made of a thermosetting resin blended with an inorganic pigment is usually 0.01-100 μm, preferably 2-20 μm.
If the thickness of the undercoat layer is less than 0.01 μm, the influence of the defects of the conductive substrate 1 affects the image, and if it exceeds 100 μm, the residual potential increases, which is not preferable.
The undercoat layer 2a is formed by applying a thermosetting resin containing an inorganic pigment to the conductive substrate 1 by blade coating, dip coating, spray coating, beat coating, nozzle coating, etc., and heating to dry. It is formed by curing.
[0008]
In the present invention, an undercoat layer 2a made of a thermosetting resin containing an inorganic pigment is formed on the conductive substrate 1, and an intermediate resin layer 2b is formed thereon.
The resin used for the resin intermediate layer 2b is a resin having high solvent resistance with respect to a general organic solvent in consideration of application using a solvent when forming the photosensitive layer 3 on the undercoat layer 2a. It is desirable.
Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resins, alkyd-melamine resins, and epoxy resins. Examples thereof include a curable resin that forms a three-dimensional network structure.
Among these, alcohol-soluble polyamide resins such as copolymer nylon and methoxymethylated nylon, which have few electrical side effects, and alkyd-melamine resins can be used as preferred resins.
The thickness of the resin middle layer 2b is usually 0.01 to 10 μm, preferably 0.1 to 2 μm.
If the thickness of the resin middle layer 2b is less than 0.01 μm, the effect of suppressing charge injection is reduced, and if it exceeds 10 μm, the residual potential increases, which is not desirable.
[0009]
The present invention is an electrophotographic photosensitive member obtained by laminating an undercoat layer 2a made of a thermosetting resin mixed with an inorganic pigment, a resin intermediate layer 2b, and a photosensitive layer 3 on a conductive substrate 1, and this resin. The electrophotographic photosensitive member is characterized in that a surfactant is contained in the intermediate layer 2b. As the surfactant to be contained in the resin intermediate layer 2b, polymer fatty acid esters such as sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, glycerin fatty acid ester, decaglycerin fatty acid ester, polyglycerin fatty acid ester, polyethylene glycol fatty acid ester, Polymer alkyl ethers such as polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether, polymer alkyl amines such as polyoxyethylene alkyl amine, polymer fatty acid amides such as polyoxyethylene alkyl fatty acid amide, polyoxyethylene Examples thereof include polymer fatty acid salts such as alkyl ether acetates and polymer alkyl ether phosphates such as polyoxyethylene alkyl ether phosphates. Among these surfactants, surfactants having a hydrophilic / lipophilic balance (HLB) of 6 to 12 are preferable. Tables 1 and 2 show examples of surfactants having an HLB of 6-12.
[Table 1]

[Table 2]

In particular, the following general formula (1)
[Chemical 3]

(In the formula, M is an alkali metal, R ₁ and R ₂ are hydrogen or an alkyl group having 4 to 20 carbon atoms, and m and n are integers of 2 to 10). However, it is preferably used because it has few electrostatic side effects. Among these, R _{1 to} R ₂ are alkyl groups having 12 to 15 carbon atoms, and polyoxyethylene alkyl ether phosphoric acid in which m and n are integers of 2 to 8 is a particularly preferable surfactant. In addition, the following general formula (2)
[Formula 4]

(Wherein R ₁ , R ₂ and R ₃ are hydrogen or an alkyl group having 4 to 20 carbon atoms, and l, m and n are integers of 2 to 10). Are preferably used because they have less electrostatic side effects. Among them, R ₁ , R ₂ , and R ₃ are alkyl groups having 12 to 15 carbon atoms, and polyoxyethylene alkyl ether phosphoric acid in which l, m, and n are integers of 2 to 8 are particularly preferable surfactants.
[0010]
The amount of the surfactant contained in the resin intermediate layer 2b is usually 1 to 200 parts, preferably 10 to 100 parts based on 100 parts by weight.
If the surfactant content is less than 1 part, the generated charge may not move smoothly through the resin intermediate layer. If it exceeds 200 parts, compatibility with the resin may deteriorate or dark decay may occur. This is not desirable.
[0011]
The present invention is an electrophotographic photosensitive member obtained by laminating an undercoat layer 2 a made of a thermosetting resin containing an inorganic pigment, a resin intermediate layer 2 b and a photosensitive layer 3 on a conductive substrate 1.
As described above, the photosensitive layer is usually formed from the charge generation layer 3a and the charge transport layer 3b that form the photosensitive layer 3.
Moreover, it is applied to both a single layer type and a function separation type.
The charge generation layer 3a is a layer mainly composed of a charge generation material, and a binder resin may be used as necessary.
As the charge generation substance, an inorganic material or an organic material can be used.
Examples of inorganic materials include crystalline selenium, amol / fasselen, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, amorphous silicon, and the like.
In the case of amorphous silicon, those obtained by terminating dangling bonds with hydrogen atoms or halogen atoms or those doped with boron atoms or phosphorus atoms are preferably used.
A known material can be used as the organic material.
For example, phthalocyanine pigments such as metal phthalone and metal-free phthalocyanine, azulenicium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzo An azo pigment having a thiophene skeleton, an azo pigment having a fluorenone skeleton, an azo pigment having an oxadiazole skeleton, an azo pigment having a bis-stilbene skeleton, an azo pigment having a distyryl oxadiazole skeleton, an azo pigment having a distyrylcarbazole skeleton Perylene pigment, anthraquinone or polycyclic quinone pigment, quinoneimine pigment, diphenylmethane or triphenylmethane pigment, benzoquinone or naphthoquinone pigment, cyanine or azomethine pigment, indigo Id based pigments, and bisbenzimidazole pigments.
These charge generation materials can be used alone or as a mixture of two or more.
The binder resin used as needed includes polyamide resin, polyurethane resin, epoxy resin, polyketone resin, polycarbonate resin, silicone resin, acrylic resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl ketone resin, polystyrene resin, poly-N. -Vinyl carbazole resin, polyacrylamide resin, etc. are mentioned.
These binder resins can be used alone or as a mixture of two or more.
Moreover, you may add the following charge transport material as needed.
When the binder resin is used, the amount of the binder resin is 10 to 500 parts, and preferably 25 to 300 parts, based on 100 parts by weight.
[0012]
The method of forming the charge generation layer 3a is roughly classified into a vacuum thin film manufacturing method and a casting method from a solution dispersion system.
Examples of the former method include a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, and a CVD (chemical vapor deposition) method.
When the charge generation layer 3a is formed by the latter casting method, a ball mill, an asanotriter, a sand mill is used by using a solvent such as tetrahydrofuran, cyclohexyne, dioxane, dichloroethane, butanone and the charge generation material as necessary together with a binder resin. It can be formed by dispersing by dispersion, etc. and applying the solution after diluting the dispersion appropriately.
The coating can be performed using a dip coating method, a spray coating method, a bead coating method, or the like.
The thickness of the charge generation layer thus formed is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.
[0013]
The charge transport layer 3b is formed by dissolving or dispersing a charge transport material and a binder resin in an appropriate solvent, and applying and drying the solution.
Moreover, a plasticizer and a leveling agent can also be added as needed.
Examples of the charge transport material include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, Examples include styryl anthracene, styryl pyrazoline, phenylhydrazones, α-phenyl stilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, and thiophene derivatives.
These charge transport materials can be used alone or as a mixture of two or more.
The binder resin used for the charge transport layer is polycarbonate resin (bisphenol A type, bisphenol Z type), polyester resin, methacrylic resin, acrylic resin, polyethylene resin, vinyl chloride resin, vinyl acetate resin, polystyrene resin, phenol resin, epoxy. Examples thereof include resins, polyurethane resins, polyvinylidene chloride resins, alkyd resins, silicon resins, polyvinyl carbazole resins, polyvinyl butyral resins, polyvinyl formal resins, polyacrylate resins, polyacrylamide resins, and phenoxy resins.
These binder resins can be used alone or as a mixture of two or more.
[0014]
In addition, a polymer charge transport material having both a binder function and a charge transport function can be used as the binder resin.
Examples of the polymer charge transporting material used in this case include a polymer having a carbazole ring in the main chain and / or side chain, for example, poly-N-vinylcarbazole (JP-A-50-82056). JP, 54-9963, JP 54-11737, JP 4183719).
Moreover, the polymer which has a hydrazone structure in a principal chain and / or a side chain can also be mentioned (Unexamined-Japanese-Patent No. 57-78402, Unexamined-Japanese-Patent No. 3-50555).
Polysilylene polymers can also be used (Japanese Patent Laid-Open Nos. 63-285552, 5-19497, and 5-70595).
Further, a polymer having a tertiary amine structure in the main chain and / or side chain, for example, N, N-bis (4-methylphenyl) -4-aminopolystyrene can also be used (Japanese Patent Laid-Open No. 1-13061). (Japanese Patent Laid-Open Nos. 1-19049, 1-1728, 1-105260, 2-167335, 5-66598, and 5-40350) .
Other examples include a formaldehyde condensation polymer of nitropyrene (Japanese Patent Laid-Open Nos. 51-73888 and 56-150749).
These polymer charge transport materials are not limited to those described above, and general copolymers, block copolymers, graft copolymers, star polymers, crosslinked polymers having an electron donating group, and the like may be used. It is possible (JP-A-3-109406).
The ratio of binder resin to charge transport material is usually 20 to 300 parts, preferably 40 to 150 parts, based on weight, with respect to 100 parts of binder resin.
[0015]
In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer 3b.
As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is suitably about 0 to 30% based on the weight of the binder resin. is there.
As the leveling agent, a polymer or oligomer having a perfluoroalkyl group in the side chain is used, and the amount used is suitably about 0 to 1% based on the weight of the binder resin.
The charge transport layer has a thickness of about 5 to 100 μm.
[0016]
Next, the case where the photosensitive layer has a single layer structure will be described.
When a single-layer photosensitive layer is formed by a casting method, a function-separated type composed of a charge generation material and a charge transport material is often used.
In this case, the charge generating material and the charge transporting material are as described above, and can be formed by dissolving or dispersing the charge generating material, the charge transporting material and the binder resin in an appropriate solvent, and applying and drying the solution. .
Moreover, a plasticizer and a leveling agent can also be added as needed.
As the binder resin, a binder resin used for the charge transport layer 3b is used, and a binder resin used for the charge generation layer 3a may be mixed and used.
The plasticizer and leveling agent are the same as above.
In the single-layer photosensitive layer, the charge generation material, the charge transport material, and the binder resin are dispersed by a ball mill, an attritor, a sand mill or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone, and the dispersion is appropriately diluted. Can be formed by coating.
The coating can be performed using a dip coating method, a spray coating method, a bead coating method, or the like.
A photoreceptor obtained by adding a charge transport material to a eutectic complex formed from a pyrylium dye and a bisphenol A polycarbonate resin can also be formed by the same coating method using an appropriate solvent.
The thickness of the single-layer photosensitive layer is suitably about 5 to 100 μm.
[0017]
In the present invention, an antioxidant can be added to improve environmental resistance, in particular, to prevent a decrease in sensitivity and an increase in residual potential.
The antioxidant may be added to any layer containing an organic substance, but is preferably added to a layer containing a charge transport material.
Antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di- Monophenolic compounds such as -t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4 -Ethyl-6-t-butylphenol), 4,4'-thiobis- (3-methyl-6-t-butylphenol), 4,4'-butylidenebis- (3-methyl-6-t-butylphenol) Compounds, 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di- t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis ( 4′-Hydroxy-3′-t-butylphenyl) butyric acid] cricol ester, tocopherols and other high molecular phenolic compounds, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N ′ -Di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'-di-isopropyl-p-phenylenediamine, N, N'-dimethyl-N, Paraphenylenediamines such as N′-di-t-butyl-p-phenylenediamine, 2,5-di-t-octylhydroquinone, 2,6-didede Hydroquinones such as silhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone, dilauryl-3,3 Organic sulfur compounds such as' -thiodipropionate, distearyl-3,3'-thiodipropionate, ditetradecyl-3,3'-dithiodipropionate, triphenylphosphine, tri (nonylphenyl) phosphine, tri And organic phosphorus compounds such as (dinonylphenyl) phosphine, tricresylphosphine, and tri (2,4-dibutylphenoxy) phosphine.
These compounds are known as antioxidants for rubbers, plastics, oils and the like, and commercially available products can be easily obtained.
The addition amount of the antioxidant is usually 0.1 to 100 parts, and preferably 2 to 30 parts with respect to 100 parts of the charge transport material on a weight basis.
[0018]
The present invention relates to an electrophotographic photosensitive member formed by laminating an undercoat layer made of a thermosetting resin containing an inorganic pigment, a resin intermediate layer, and a photosensitive layer on a conductive substrate, the interface being formed on the resin intermediate layer. Provided is an electrophotographic photosensitive member characterized by containing an activator, and an image forming apparatus characterized by providing the electrophotographic photosensitive member.
As the image forming apparatus itself, an image forming apparatus used for a normal copying machine, printer, facsimile, or the like can be adopted in addition to the provision of the electrophotographic photosensitive member.
[0019]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
In the following, “parts” means parts by weight.
[0020]
Reference example 1
On an aluminum cylindrical substrate having a diameter of 30 mm, an undercoat layer coating solution, a resin intermediate layer coating solution, a charge generation layer coating solution, a charge transport layer coating solution, and a charge injection layer coating are provided. The coating solution is applied and dried sequentially to form an undercoat layer of about 3 μm, an intermediate resin layer of about 0.2 μm, a charge generation layer of about 0.3 μm, and a charge transport layer of about 20 μm by dip coating. Thus, an electrophotographic photosensitive member was produced.
[Coating liquid for undercoat layer]
Alkyd resin solution (Dainippon Ink Chemical Co., Ltd.)
: Beckolite M-6401-50) 375 parts Melamine resin solution (Dainippon Ink & Chemicals, Inc.)
: Super becamine G821-60) 210 parts Titanium dioxide (Ishihara Sangyo)
: Typeke CR-EL) 1250 parts 2-butanone 7800 parts [coating liquid for resin intermediate layer]
Polyamide resin (Toray: Amilan CM8000) 2 parts Compound No. 1 shown in Table 1 2 2 parts n-butanol 40 parts methanol 60 parts [coating solution for charge generation layer]
Charge generation material with the following structure 5 parts

Polyvinyl butyral (UCC: XYHL) 2 parts Cyclohexanone 200 parts Tetrahydrofuran 200 parts [Coating liquid for charge transport layer]
Bisphenol Z-type polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

90 parts of methylene chloride [0021]
Example 1
The compounds contained in the resin intermediate layer are compound Nos. Shown in Table 2. An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the number was changed to 10.
[0022]
Example 2
The compounds contained in the resin intermediate layer are compound Nos. Shown in Table 2. An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that it was replaced with 11.
[0023]
Example 3
Implemented except that the polyamide resin used for the resin intermediate layer was replaced with 3 parts of oil-free alkyd resin (Dainippon Ink: Beckolite M6401-50) and 2 parts of butylmelamine resin (Dainippon Ink: Super Beckamine G821-30) An electrophotographic photosensitive member was produced in the same manner as in Example 1 .
[0024]
Example 4
The compounds contained in the resin intermediate layer are compound Nos. Shown in Table 2. An electrophotographic photosensitive member was produced in the same manner as in Example 3 except that it was replaced with 11.
[0025]
Comparative Example 1
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the surfactant was not included in the resin intermediate layer.
[0026]
Comparative Example 2
An electrophotographic photosensitive member was produced in the same manner as in Example 3 except that the surfactant was not included in the resin intermediate layer.
[0027]
Example 5
The electrophotographic photosensitive member produced in Reference Example 1 and Examples 1 to 4 was subjected to a paper passing test of 5,000 sheets using a modified product of a commercially available copying machine imagio MF2200 (manufactured by Ricoh Co., Ltd.), and then in the actual machine The surface potential of the exposed part and the non-exposed part of the photoreceptor was measured. The results are shown in Table 3.
[0028]
Comparative Example 3
The electrophotographic photoreceptors produced in Comparative Examples 1 and 2 were subjected to a paper passing test in the same manner as in Example 5, and then the surface potentials of the exposed and unexposed parts of the photoreceptor in the actual machine were measured. The results are shown in Table 3.
[Table 3]

As shown in Table 3, in the electrophotographic photosensitive member of the present invention, the surface potential of the exposed portion hardly changed after the 5,000 sheet passing test, and the residual potential was reduced. In the electrophotographic photosensitive member to which the surfactant of the comparative example was not added, the surface potential of the exposed portion was increased and the residual potential was accumulated.
[0029]
【The invention's effect】
According to the present invention, an electrophotographic photosensitive member capable of providing a stable image for a long period of time and an image forming apparatus provided with the same are provided, and the image forming apparatus such as a copying machine, a printer, or a facsimile is designed and manufactured. There is a lot to contribute.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of one electrophotographic photoreceptor according to the present invention.
FIG. 2 is a schematic cross-sectional view of another electrophotographic photoreceptor according to the present invention.
FIG. 3 is a schematic cross-sectional view of another electrophotographic photoreceptor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Conductive base | substrate 2a Undercoat layer 2b which mix | blends an inorganic pigment and consists of thermosetting resin Resin intermediate | middle layer 3 Photosensitive layer 3a Charge generation layer 3b which forms the photosensitive layer 3 Charge transport layer which forms the photosensitive layer 3

Claims (6)

On a conductive substrate, the bottom made of a thermosetting resin containing an inorganic pigment coating layer, an electrophotographic photoreceptor obtained by laminating the resin intermediate layer and a photosensitive layer, the resin intermediate layer containing a surface active agent The surfactant is represented by the following general formula (1)

(Wherein, M is an alkali metal, R ₁ and R ₂ are hydrogen or an alkyl group having 4 to 20 carbon atoms, and m and n are integers of 2 to 10). Electrophotographic photoreceptor. An electrophotographic photosensitive member in which an undercoat layer made of a thermosetting resin blended with an inorganic pigment, a resin intermediate layer, and a photosensitive layer are laminated on a conductive substrate, the resin intermediate layer containing a surfactant The surfactant is represented by the following general formula (2)

(Wherein R ₁ , R ₂ and R ₃ are hydrogen or an alkyl group having 4 to 20 carbon atoms, and l, m and n are integers of 2 to 10). Electrophotographic photoreceptor. Resin intermediate layer, the electrophotographic photosensitive member according to claim 1 or 2 is one formed by polyamide resin. The electrophotographic photosensitive member according to claim 1 or 2 in which the resin intermediate layer is formed by the cured product of alkyd resins and melamine resins. The hydrophilic-lipophilic balance (HLB) of the surfactant is, an electrophotographic photosensitive member according to any one of claims 1-4 6-12. An image forming apparatus characterized by comprising an electrophotographic photosensitive member according to any one of claims 1-5.

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