JP3835153B2 - Electrophotographic photoreceptor - Google Patents

Description

【００１３】
（一般式（１）中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴及びＲ⁹はそれぞれ独立に炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシル基、ハロゲン化アルキル基、又は炭素数６〜２０の置換されていてもよい芳香族基を示す。Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸及びＲ¹⁰はそれぞれ独立に水素原子、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシル基、ハロゲン、ハロゲン化アルキル基、炭素数６〜２０の置換されてもよい芳香族基を示す。また、Ｒ⁹とＲ¹⁰はお互いに結合していてもよい。）
【００１４】
【発明の実施の形態】
以下本発明を詳細に説明する。
＜ポリアリレート樹脂＞
本発明の電子写真感光体は、感光層に上記一般式（１）に示される繰り返し単位を主成分とするポリアリレート樹脂を含有するものである。
【００１５】
一般式（１）で表されるポリアリレート樹脂の構造の具体例は、例えば以下のものが挙げられる。前述の一般式（１）中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴及びＲ⁹は、各々独立に、炭素数１〜６のアルキル基、炭素数１〜４のアルコキシル基、ハロゲン化アルキル基、炭素数６〜２０の置換されていても良い芳香族基を表し、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸及びＲ¹⁰は、各々独立に、水素原子、炭素数１〜６のアルキル基、炭素数１〜４のアルコキシル基、ハロゲン、ハロゲン化アルキル基、炭素数６〜２０の置換されていても良い芳香族基を表すが、炭素数１〜６のアルキル基は例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基、ｎ−ベンチル基、ｓｅｃ−ペンチル基、ｎ−ヘキシル基等が挙げられ、アルコキシ基としては、例えばメトキシ基、エトキシ基、ｎ−プロポキシ基、ｎ−ブトキシ基等が挙げられる。またハロゲンには塩素原子、臭素原子、フッ素原子などが挙げられ、ハロゲン化アルキル基としてはクロロメチル基、ジクロロメチル基、トリクロロメチル基、トリフルオロメチル基等が挙げられる。置換されても良い芳香族基には、フェニル基、４−メチルフェニル基、ナフチル基等が挙げられる。
【００１６】
これらの中で、好ましくは、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は各々独立に炭素数１〜６のアルキル基であり、Ｒ⁵、Ｒ⁶、Ｒ⁷及びＲ⁸は、各々独立に水素原子であり、Ｒ⁹及びＲ¹⁰は各々独立に炭素数１〜６のアルキル基である。
また特に好ましくは、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁹及びＲ¹⁰は各々メチル基である。
【００１７】
上記一般式（１）中の、下記一般式（３）で表される構造は、本発明で用いられるポリアリレート樹脂を製造する際に用いられる、ビスフェノール成分に由来する残基である。
【００１８】
【化４】

【００１９】
ビスフェノール成分の具体例としては、１，１−ビス−（４−ヒドロキシ−３，５−ジメチルフェニル）エタン、２，２−ビス−（４−ヒドロキシ−３，５−ジメチルフェニル）プロパン、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）フェニルメタン、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）ジフェニルメタン、１，１−ビス−（４−ヒドロキシ−３，５−ジメチルフェニル）フェニルエタン、１，１−ビス−（４−ヒドロキシ−３，５−ジメチルフェニル）シクロヘキサン、１，１−ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）エタン、２，２−ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）プロパン、ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）フェニルメタン、ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）ジフェニルメタン、１，１−ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）フェニルエタン、１，１−ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）シクロヘキサン、１，１−ビス−（４−ヒドロキシ−２，３，５−トリメチルフェニル）エタン、２，２−ビス−（４−ヒドロキシ−２，３，５−トリメチルフェニル）プロパン、ビス−（４−ヒドロキシ−２，３，５−トリメチルフェニル）フェニルメチン、１，１−ビス−（４−ヒドロキシ−２，３，５−トリメチルフェニル）フェニルエタン、１，１−ビス−（４−ヒドロキシ−２，３，５−トリメチルフェニル）シクロヘキサン、などが挙げられる。これらの中で好ましい例としては、
１，１−ビス−（４−ヒドロキシ−３，５−ジメチルフェニル）エタン、２，２−ビス−（４−ヒドロキシ−３，５−ジメチルフェニル）プロパン、１，１−ビス−（４−ヒドロキシ−３，５−ジメチルフェニル）シクロヘキサン、１，１−ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）エタン、２，２−ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）プロパン、１，１−ビス−（４−ヒドロキシ−３，５−ジ（ｔ−ブチル）フェニル）シクロヘキサン、などが挙げられる。また、これらの中で特に好ましくは、２，２−ビス（４−ヒドロキシ−３，５−ジメチルフェニル）プロパンである。
＜ポリアリレート樹脂の製造方法＞
本発明の電子写真感光体用樹脂の製造方法として、公知の重合方法を用いることができる。例えば界面重合法、溶融重合法、溶液重合法などが挙げられる。
【００２０】
例えば、界面重合法による製造の場合は、二官能性フェノール成分もしくはビスフェノール成分をアルカリ水溶液に溶解した溶液と、芳香族ジカルボン酸クロライド成分を溶解したハロゲン化炭化水素の溶液とを混合する。この際、触媒として、四級アンモニウム塩もしくは四級ホスホニウム塩を存在させることも可能である。重合温度は通常０〜４０℃の範囲、重合時間は２〜１２時間の範囲であるのが生産性の点で好ましい。重合終了後、水相と有機相を分離し、有機相中に溶解しているポリマーを公知の方法で、洗浄、回収することにより、目的とする樹脂を得られる。
【００２１】
ここで用いられるアルカリ成分としては、水酸化ナトリウム、水酸化カリウム等のアルカリ金属の水酸化物等を挙げることができる。アルカリの使用量としては、反応系中に含まれるフェノール性水酸基の１．０１〜３倍当量の範囲が好ましい。
また、ここで用いられる、ハロゲン化炭化水素としては、ジクロロメタン、クロロホルム、１，２−ジクロロエタン、トリクロロエタン、テトラクロロエタン、ジクロルベンゼンなどを挙げることができる。
【００２２】
触媒として用いられる四級アンモニウム塩もしくは四級ホスホニウム塩としては、トリブチルアミンやトリオクチルアミン等の三級アルキルアミンの塩酸、臭素酸、ヨウ素酸等の塩、ベンジルトリエチルアンモニウムクロライド、ベンジルトリメチルアンモニウムクロライド、ベンジルトリブチルアンモニウムクロライド、テトラエチルアンモニウムクロライド、テトラブチルアンモニウムクロライド、テトラブチルアンモニウムブロマイド、トリオクチルメチルアンモニウムクロライド、テトラブチルホスホニウムブロマイド、トリエチルオクタデシルホスホニウムブロマイド、Ｎ−ラウリルピリジニウムクロライド、ラウリルピコリニウムクロライドなどが挙げられる。
【００２３】
芳香族ジカルボン酸クロライド成分としては、主にテレフタル酸クロライドが用いられる。
ビスフェノール成分の具体例としては、上述したとおりであり、前記化合物の１種もしくは２種以上混合して用いることも可能である。
また、この重合の際に分子量調節剤としてフェノール、ｏ，ｍ，ｐ−クレゾール、ｏ，ｍ，ｐ−エチルフェノール、ｏ，ｍ，ｐ−プロピルフェノール、ｏ，ｍ，ｐ−ｔｅｒｔ−ブチルフェノール、ペンチルフェノール、ヘキシルフェノール、オクチルフェノール、ノニルフェノール、２，６−ジメチルフェノール等のアルキルフェノール類、ｏ，ｍ，ｐ−フェニルフェノール等の一官能性のフェノール、酢酸クロリド、酪酸クロリド、オクチル酸クロリド、塩化ベンゾイル、ベンゼンスルフォニルクロリド、ベンゼンスルフィニルクロリド、スルフィニルクロリド、ベンゼンホスホニルクロリドやそれらの置換体等の一官能性の酸ハロゲン化物を存在させても良い。
【００２４】
本発明の一般式（１）に示される繰り返し単位を主成分とするポリアリレート樹脂は、粘度平均分子量が通常、１万〜３０万であるが、好ましくは１５，０００〜１０万、さらに好ましくは２万〜５万である。粘度平均分子量が小さすぎると樹脂の機械的強度が低下し実用的でなく、大きすぎると、適当な膜厚に塗布する事が困難である。
【００２５】
また、一般式（１）に示される繰り返し単位を主成分とするポリアリレート樹脂において、「主成分とする」とは、一般式（１）の繰り返し単位を、８０％以上を含有することを意味するものであり、好ましくは、９５％以上、特に好ましくは１００％のものである。この繰り返し単位が少なすぎる場合、電気特性、特に応答性が低下し好ましくない。このとき、上述した分子量調整剤など、分子鎖末端に存在する基は繰り返し単位に含まれるものではない。
【００２６】
また、本発明のポリアリレート構造を有する樹脂は、他の樹脂と混合して、電子写真感光体に用いることも可能である。ここで混合される他の樹脂としては、ポリメチルメタクリレート、ポリスチレン、ポリ塩化ビニル等のビニル重合体、及びその共重合体、ポリカーボネート、ポリエステル、ポリスルホン、フェノキシ、エポキシ、シリコーン樹脂等の熱可塑性樹脂や種々の熱硬化性樹脂などが挙げられる。これら樹脂のなかでもポリカーボネート樹脂が好ましいものとして挙げられる。
＜電子写真感光体＞
上述した本発明の樹脂は電子写真感光体に用いられ、該感光体の導電性支持体上に設けられる感光層中のバインダー樹脂として用いられる。
【００２７】
導電性支持体としては、例えばアルミニウム、アルミニウム合金、ステンレス鋼、銅、ニッケル等の金属材料や金属、カーボン、酸化錫などの導電性粉体を添加して導電性を付与した樹脂材料やアルミニウム、ニッケル、ＩＴＯ（酸化インジウム酸化錫合金）等の導電性材料をその表面に蒸着又は塗布した樹脂、ガラス、紙などが主として使用される。形態としては、ドラム状、シート状、ベルト状などのものが用いられる。金属材料の導電性支持体の上に、導電性・表面性などの制御のためや欠陥被覆のため、適当な抵抗値を持つ導電性材料を塗布したものでも良い。
【００２８】
導電性支持体としてアルミニウム合金等の金属材料を用いた場合、陽極酸化処理、化成皮膜処理等を施してから用いても良い。陽極酸化処理を施した場合、公知の方法により封孔処理を施すのが望ましい。
支持体表面は、平滑であっても良いし、特別な切削方法を用いたり、研磨処理を施したりすることにより、粗面化されていても良い。また、支持体を構成する材料に適当な粒径の粒子を混合することによって、粗面化されたものでも良い。
【００２９】
導電性支持体と感光層との間には、接着性・ブロッキング性等の改善のため、下引き層を設けても良い。
下引き層としては、樹脂、樹脂に金属酸化物等の粒子を分散したものなどが用いられる。
下引き層に用いる金属酸化物粒子の例としては、酸化チタン、酸化アルミニウム、酸化珪素、酸化ジルコニウム、酸化亜鉛、酸化鉄等の１種の金属元素を含む金属酸化物粒子、チタン酸カルシウム、チタン酸ストロンチウム、チタン酸バリウム等の複数の金属元素を含む金属酸化物粒子が挙げられる。一種類の粒子のみを用いても良いし複数の種類の粒子を混合して用いても良い。これらの金属酸化物粒子の中で、酸化チタンおよび酸化アルミニウムが好ましく、特に酸化チタンが好ましい。酸化チタン粒子は、その表面に、酸化錫、酸化アルミニウム、酸化アンチモン、酸化ジルコニウム、酸化珪素等の無機物、又はステアリン酸、ポリオール、シリコーン等の有機物による処理を施されていても良い。酸化チタン粒子の結晶型としては、ルチル、アナターゼ、ブルックカイト、アモルファスのいずれも用いることができる。複数の結晶状態のものが含まれていても良い。
【００３０】
また、金属酸化物粒子の粒径としては、種々のものが利用できるが、中でも特性および液の安定性の面から、平均一時粒径として１０〜１００ｎｍが好ましく、特に好ましいのは、１０〜２５ｎｍである。
下引き層は、金属酸化物粒子をバインダー樹脂に分散した形で形成するのが望ましい。下引き層に用いられるバインダー樹脂としては、フェノキシ、エポキシ、ポリビニルピロリドン、ポリビニルアルコール、カゼイン、ポリアクリル酸、セルロース類、ゼラチン、デンプン、ポリウレタン、ポリイミド、ポリアミド等が単独あるいは硬化剤とともに硬化した形で使用できるが、中でも、アルコール可溶性の共重合ポリアミド、変性ポリアミド等は良好な分散性、塗布性を示し好ましい。
【００３１】
バインダー樹脂に対する無機粒子の添加比は任意に選べるが、１０〜５００ｗｔ％の範囲で使用することが、分散液の安定性、塗布性の面で好ましい。
下引き層の膜厚は、任意に選ぶことができるが、感光体特性および塗布性から０．１〜２０μｍが好ましい。また下引き層には、公知の酸化防止剤等を添加しても良い。
【００３２】
本発明の感光層の具体的な構成として
・導電性支持体上に電荷発生物質を主成分とする電荷発生層、電荷輸送層物質及びバインダー樹脂を主成分とした電荷輸送層をこの順に積層した積層型感光体。
・導電性支持体上に、電荷輸送物質及びバインダー樹脂を主成分とした電荷輸送層、電荷発生物質を主成分とする電荷発生層をこの順に積層した逆二層型感光体。
【００３３】
・導電性支持体上に電荷輸送物質及びバインダー樹脂を含有する層中に電荷発生物質を分散させた分散型感光体。
の様な構成が基本的な形の例として挙げられる。
積層型感光体の場合、その電荷発生層に使用される電荷発生物質としては例えばセレニウム及びその合金、硫化カドミウム、その他無機系光導電材料、フタロシアニン顔料、アゾ顔料、キナクリドン顔料、インジゴ顔料、ペリレン顔料、多環キノン顔料、アントアントロン顔料、ベンズイミダゾール顔料などの有機顔料等各種光導電材料で使用でき、特に有機顔料、更にフタロシアニン顔料、アゾ顔料が好ましい。これらの微粒子をたとえばポリエステル樹脂、ポリビニルアセテート、ポリアクリル酸エステル、ポリメタクリル酸エステル、ポリエステル、ポリカーボネート、ポリビニルアセタール、ポリビニルプロピオナール、ポリビニルブチラール、フェノキシ樹脂、エポキシ樹脂、ウレタン樹脂、セルロースエステル、セルロースエーテルなどの各種バインダー樹脂で結着した形で使用される。この場合の使用比率はバインダー樹脂１００重量部に対して３０〜５００重量部の範囲より使用され、その膜厚は通常０．１μｍ〜１μｍ、好ましくは０．１５μｍ〜０．６μｍが好適である。
【００３４】
電荷発生物質としてフタロシアニン化合物を用いる場合、具体的には、無金属フタロシアニン、銅、インジウム、ガリウム、錫、チタン、亜鉛、バナジウム、シリコン、ゲルマニウム等の金属、またはその酸化物、ハロゲン化物等の配位したフタロシアニン類が使用される。３価以上の金属原子への配位子の例としては、上に示した酸素原子、塩素原子の他、水酸基、アルコキシ基などがあげられる。特に感度の高いＸ型、τ型無金属フタロシアニン、Ａ型、Ｂ型、Ｄ型等のチタニルフタロシアニン、バナジルフタロシアニン、クロロインジウムフタロシアニン、クロロガリウムフタロシアニン、ヒドロキシガリウムフタロシアニン等が好適である。なお、ここで挙げたチタニルフタロシアニンの結晶型のうち、Ａ型、Ｂ型についてはＷ．ＨｅｌｌｅｒらによってそれぞれＩ相、II相として示されており（Ｚｅｉｔ．Ｋｒｉｓｔａｌｌｏｄｒ．１５９（１９８２）１７３）、Ａ型は安定型として知られているものである。特に好ましく用いられるＤ型は、ＣｕＫα線を用いた粉末Ｘ線回折において、回折角２θ±０．２°が２７．３°に明瞭なピークを示すことを特徴とする結晶型である。フタロシアニン化合物は単一の化合物のもののみを用いても良いし、いくつかの混合状態でも良い。ここでのフタロシアニン化合物ないしは結晶状態に置ける混合状態として、それぞれの構成要素を後から混合して用いても良いし、合成、顔料化、結晶化等のフタロシアニン化合物の製造・処理工程において混合状態を生じせしめたものでも良い。このような処理としては、酸ペースト処理・磨砕処理・溶剤処理等が知られている。
【００３５】
電荷輸送層に含まれる電荷輸送物質としては、２，４，７−トリニトロフルオレノンなどの芳香族ニトロ化合物、テトラシアノキノジメタン等のシアノ化合物、ジフェノキノン等のキノン類などの電子吸引性物質、カルバゾール誘導体、インドール誘導体、イミダゾール誘導体、オキサゾール誘導体、ピラゾール誘導体、オキサジアゾール誘導体、ピラゾリン誘導体、チアジアゾール誘導体などの複素環化合物、アニリン誘導体、ヒドラゾン化合物、芳香族アミン誘導体、スチルベン誘導体、ブタジエン誘導体、エナミン化合物、これらの化合物が複数結合されたもの、あるいはこれらの化合物からなる基を主鎖もしくは側鎖に有する重合体などの電子供与性物質が挙げられる。これらの中でもカルバゾール誘導体、ヒドラゾン誘導体、芳香族アミン誘導体、スチルベン誘導体、ブタジエン誘導体及びこれらの誘導体が複数結合それたものが好ましく、芳香族アミン誘導体、スチルベン誘導体、ブタジエン誘導体の複数結合されてなるものが好ましい
具体的には、下記一般式（２）で表される構造を有するものが好ましく用いられる。
【００３６】
【化５】

【００３７】
（一般式（２）中、Ａｒ¹〜Ａｒ⁴は各々独立して、置換基を有してもよいアリーレン基又は置換基を有してもよい２価の複素環基を表す。Ａｒ⁵、Ａｒ⁶は、ｍ¹＝０、ｍ²＝０の時はそれぞれ、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、置換基を有してもよい１価の複素環基を表し、ｍ¹＝１、ｍ²＝１の時はそれぞれ置換基を有してもよいアルキレン基、置換基を有してもよいアリーレン基又は置換基を有してもよい２価の複素環基を表す。Ｑは直列結合または２価の残基を表す。Ｒ¹¹〜Ｒ¹⁸は各々独立して水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、置換基を有してもよいアラルキル基、置換基を有してもよい複素環基を表す、ｎ¹〜ｎ⁴は各々独立して０〜４の整数を表す。また、ｍ¹、ｍ²は各々独立して０又は１を表す。また、Ａｒ¹〜Ａｒ⁶は互いに結合して環状構造を形成してもよい。）
より具体的には一般式（２）中、Ｒ¹¹〜Ｒ¹⁸は各々独立して水素原子、置換基を有しても良いアルキル基、置換基を有していても良いアリール基、置換基を有していても良いアラルキル基、置換基を有していても良い複素環基を表すが、アルキル基としては、例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、シクロペンチル基、シクロヘキシル基等が挙げられ、これらの内炭素数１〜６のアルキル基が好ましい。
【００３８】
また、アリール基としては、フェニル基、トリル基、キシリル基、ナフチル基、ピレニル基等が挙げられ、炭素数６〜１２のアリール基が好ましい。
また、アラルキル基としては、ベンジル基、フェネチル基等が挙げられ、炭素数７〜１２のアラルキル基が好ましい。
また、複素環基は、芳香族性を有する複素環が好ましく、例えばフリル基、チエニル基、ピリジル基等が挙げられ、単環の芳香族複素環が更に好ましい。
【００３９】
また、Ｒ¹¹〜Ｒ¹⁸において、最も好ましいものは、メチル基及びフェニル基である。
また、一般式（２）中、Ａｒ¹〜Ａｒ⁴は各々独立して、置換基を有していても良いアリーレン基又は置換基を有していても良い２価の複素環基を表し、Ａｒ⁵、Ａｒ⁶は、ｍ¹＝０、ｍ²＝０の時はそれぞれ、置換基を有していても良いアルキル基、置換基を有していても良いアリール基、置換基を有していても良い１価の複素環基を表し、ｍ¹＝１、ｍ²＝１の時はそれぞれ、置換基を有していても良いアルキレン基、置換基を有していても良いアリーレン基又は置換基を有していても良い２価の複素環基を表すが、アリール基としては、フェニル基、トリル基、キシリル基、ナフチル基、ピレニル基等が挙げられ、炭素数６〜１４のアリール基が好ましく；アリレーン基としては、フェニレン基、ナフチレン基等が挙げられ、フェニレン基が好ましく；１価の複素環基としては、芳香族性を有する複素環が好ましく、例えばフリル基、チエニル基、ピリジル基等が挙げられ、単環の芳香族複素環が更に好ましく；２価の複素環基としては、芳香族性を有する複素環が好ましく、例えばピリジレン基、チエニレン基等が挙げられ、単環の芳香族複素環が更に好ましい。
【００４０】
これらの内、最も好ましいものは、Ａｒ¹及びＡｒ²はフェニレン基であり、Ａｒ³はフェニル基である。
これらＲ¹¹〜Ｒ¹⁸、Ａｒ¹〜Ａｒ⁶で表される基の内、アルキル基、アリール基、アラルキル基、複素環基はさらに置換基を有していても良いが、その置換基としては、シアノ基；ニトロ基；水酸基；フッ素原子、塩素原子、臭素原子、沃素原子等のハロゲン原子；メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｓ−ブチル基、ｔ−ブチル基、ペンチル基、ヘキシル基、シクロペンチル基、シクロヘキシル基等のアルキル基；メトキシ基、エトキシ基、プロピルオキシ基等のアルコキシ基；メチルチオ基、エチルチオ基等のアルキルチオ基；ビニル基、アリル基等のアルケニル基；ベンジル基、ナフチルメチル基、フェネチル基等のアラルキル基；フェノキシ基、トリロキシ基等のアリールオキシ基；ベンジルオキシ基、フェネチルオキシ基等のアリールアルコキシ基；フェニル基、ナフチル基等のアリール基；スチリル基、ナフチルビニル基等のアリールビニル基；アセチル基、ベンゾイル基等のアシル基；ジメチルアミノ基、ジエチルアミノ基等のジアルキルアミノ基；ジフェニルアミノ基、ジナフチルアミノ基等のジアリールアミノ基；ジベンジルアミノ基、ジフェネチルアミノ基等のジアラルキルアミノ基、ジピリジルアミノ基、ジチエニルアミノ基等のジ複素環アミノ基；ジアリルアミノ基、又、上記のアミノ基の置換基を組み合わせたジ置換アミノ基等の置換アミノ基等が挙げられる。
【００４１】
また、これらの置換基は互いに結合して、単結合、メチレン基、エチレン基、カルボニル基、ビニリデン基、エチレニレン基等を介した環状炭化水素基や複素環基を形成してもよい。
これらの内好ましい置換基としては、ハロゲン原子、シアノ基、水酸基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルキルチオ基、炭素数６〜１２のアリールオキシ基、炭素数６〜１２のアリールチオ基、炭素数２〜８のジアルキルアミノ基が挙げられ、ハロゲン原子、炭素数１〜６のアルキル基、フェニル基が更に好ましく、メチル基、フェニル基が特に好ましい。
【００４２】
一般式（２）中、ｎ¹〜ｎ⁴は各々独立して０〜４の整数を表すが、０〜２が好ましく、１が最も好ましい。ｍ¹、ｍ²は０又は１を表すが、０が好ましい。
一般式（２）中、Ｑは、直接結合又は２価の残基を表すが、２価の残基として好ましいものは、１６族原子、置換基を有しても良いアルキレン、置換基を有しても良いアリーレン基、置換基を有しても良いシクロアルキリデン基、またはこれらが互いに結合した、例えば［−Ｏ−Ａ−Ｏ−］、［−Ａ−Ｏ−Ａ−］、［−Ｓ−Ａ−Ｓ−］、［−Ａ−Ａ−］等が挙げられる（但し、Ａは置換基を有しても良いアリーレン基または置換基を有しても良いアルキレン基を表す。）
Ｑを構成するアルキレン基としては、炭素数１〜６のものが好ましく、中でもメチレン基及びエチレン基が更に好ましい。また、シクロアルキリデン基としては、炭素数５〜８のものが好ましく、中でもシクロペンチリデン基及びシクロヘキシリデン基が更に好ましい。アリーレン基としては、炭素数６〜１４のものが好ましく、中でもフェニレン基及びナフチレン基が更に好ましい。
【００４３】
また、これらアルキレン基、アリーレン基、シクロアルキリデン基は置換基を有してもよいが、好ましい置換基としては、水酸基、ニトロ基、シアノ基、ハロゲン原子、炭素数１〜６のアルキル基、炭素数１〜６のアルケニル基、炭素数６〜１４のアリール基が挙げられる。
これら電荷輸送物質は単独で用いても良いし、いくつかを混合して用いてもよい。これらの電荷輸送材料がバインダー樹脂に結着した形で電荷輸送層が形成される。電荷輸送層は、単一の層から成っていても良いし、構成成分あるいは組成比の異なる複数の層を重ねたものでも良い。
【００４４】
バインダー樹脂と電荷輸送物質の割合は、通常、バインダー樹脂１００重量部に対して通常３０〜２００重量部、好ましくは４０〜１５０重量部の範囲で使用される。また膜厚は一般に５〜５０μｍ、好ましくは１０〜４５μｍがよい。
なお、電荷輸送層には成膜性、可撓性、塗布性、耐汚染性、耐ガス性、耐光性などを向上させるために周知の可塑剤、酸化防止剤、紫外線吸収剤、電子吸引性化合物、レベリング剤などの添加物を含有させても良い。
【００４５】
酸化防止剤の例としては、ヒンダードフェノール化合物、ヒンダードアミン化合物などが挙げられる。
分散型感光層の場合には、上記のような配合比の電荷輸送媒体中に、前出の電荷発生物質が分散される。
その場合の電荷発生物質の粒子径は充分小さいことが必要であり、好ましくは１μｍ以下より好ましくは０．５μｍ以下で使用される。感光層内に分散される電荷発生物質の量は少なすぎると充分な感度が得られず、多すぎると帯電性の低下、感度の低下などの弊害があり、例えば好ましくは０．５〜５０重量％の範囲で、より好ましくは１〜２０重量％の範囲で使用される。
【００４６】
感光層の膜厚は通常５〜５０μｍ、より好ましくは１０〜４５μｍで使用される。またこの場合にも成膜性、可撓性、機械的強度等を改良するための公知の可塑剤、残留電位を抑制するための添加剤、分散安定性向上のための分散補助剤、塗布性を改善するためのレベリング剤、界面活性剤、例えばシリコーンオイル、フッ素系オイルその他の添加剤が添加されていても良い。
【００４７】
感光層の上に、感光層の損耗を防止したり、帯電器等から発生する放電生成物等による感光層の劣化を防止・軽減する目的で保護層を設けても良い。
また、感光体表面の摩擦抵抗や、摩耗を軽減する目的で、表面の層にはフッ素系樹脂、シリコーン樹脂等を含んでいても良い。また、これらの樹脂からなる粒子や無機化合物の粒子を含んでいても良い。
【００４８】
これらの感光体を構成する各層は、支持体上に浸漬塗布、スプレー塗布、ノズル塗布、バーコート、ロールコート、ブレード塗布等により塗布して形成される。
各層の形成方法としては、層に含有させる物質を溶剤に溶解又は分散させて得られた塗布液を順次塗布するなどの公知の方法が適用できる。
【００４９】
本発明の電子写真感光体を使用する複写機・プリンター等の電子写真装置は、少なくとも帯電、露光、現像、転写の各プロセスを含むが、どのプロセスも通常用いられる方法のいずれを用いても良い。帯電方法（帯電器）としては、例えばコロナ放電を利用したコロトロンあるいはスコロトロン帯電、導電性ローラーあるいはブラシ、フィルムなどによる接触帯電などいずれを用いても良い。このうち、コロナ放電を利用した帯電方法では暗部電位を一定に保つためにスコロトン帯電が用いられることが多い。現像方法としては、磁性あるいは非磁性の一成分現像剤、二成分現像剤などを接触あるいは非接触させて現像する一般的な方法が用いられる。転写方法としては、コロナ放電によるもの、転写ローラーあるいは転写ベルトを用いた方法等いずれでもよい。転写は、紙やＯＨＰ用フィルム等に対して直接行っても良いし、一旦中間転写体（ベルト状あるいはドラム状）に転写したのちに、紙やＯＨＰ用フィルム上に転写しても良い。
【００５０】
通常、転写の後、現像剤を紙などに定着させる定着プロセスが用いられ、定着手段としては一般的に用いられる熱定着、圧力定着などを用いることができる。これらのプロセスのほかに、通常用いられるクリーニング、除電等のプロセスを有しても良い。
【００５１】
【実施例】
以下、本発明の具体的態様を実施例によりさらに詳細に説明するが、本発明はその要旨を越えない限り、これらの実施例によって限定されるものではない。
＜ポリアリレート樹脂の製造＞
［粘度平均分子量］
ポリアリレート樹脂をジクロロメタンに溶解し濃度Ｃが６．００ｇ／Ｌの溶液を調整した。溶媒（ジクロロメタン）の流下時間ｔ₀が１３６．１６秒のウベローデ型毛細管粘度計を用いて、２０．０℃に設定した恒温水槽中で試料溶液の流下時間ｔを測定した。以下の式に従って粘度平均分子量Ｍｖを算出した。
【００５２】
【数１】
ａ＝０．４３８×η_sp＋１ η_sp＝ｔ／ｔ₀−１
ｂ＝１００×η_sp／Ｃ Ｃ＝６．００（ｇ／Ｌ）
η＝ｂ／ａ
Ｍｖ＝３２０７×η^1.205
製造例１（実施例１のポリアリレート樹脂Ａの製造法）
１Ｌビーカーに水酸化ナトリウム（４．５１ｇ）とＨ₂Ｏ（４００ｍｌ）を秤取り、窒素バブリングしながら撹拌し溶解させた。そこにｐ−ｔｅｒｔ−ブチルフェノール（０．３３ｇ）、ベンジルトリエチルアンモニウムクロライド（０．０５６７ｇ）および２，２−ビス（４−ヒドロキシ−３，５−ジメチルフェニル）プロパン［テトラメチルビスフェノールＡ］（１１．９９ｇ）の順に添加、撹拌した後、このアルカリ水溶液を１Ｌ反応槽に移した。
【００５３】
別途、テレフタル酸クロライド（８．８０ｇ）をジクロロメタン（２００ｍｌ）に溶解し２００ｍｌ滴下ロート内に移した。
重合槽の外温を２０℃に保ち、反応槽内のアルカリ水溶液を撹拌しながら、滴下ロートよりジクロロメタン溶液を１時間かけて滴下した。さらに３時間撹拌を続けた後、酢酸（１．４９ｍｌ）、ジクロロメタン（１００ｍｌ）を加え３０分撹拌した。その後、撹拌を停止し有機層を分離した。この有機層を０．１Ｎ水酸化ナトリウム水溶液（２２６ｍｌ）にて洗浄を２回行い、次に０．１Ｎ塩酸（２２６ｍｌ）にて洗浄を２回行い、さらにＨ₂Ｏ（２２６ｍｌ）にて洗浄を２回行った。
【００５４】
洗浄後の有機層をメタノール（１５００ｍｌ）に注いで得られた沈殿物を濾過にて取り出し、乾燥して目的のポリアリレート樹脂Ａを得た。得られたポリアリレート樹脂Ａの粘度平均分子量は２３，２００であった。構造式を以下に示す。
【００５５】
【化６】

【００５６】
製造例２（比較例１のポリアリレート樹脂Ｂの製造法）
１Ｌビーカーに水酸化ナトリウム（６．７７ｇ）とＨ₂Ｏ（６００ｍｌ）を秤取り、窒素バブリングしながら撹拌し溶解させた。そこにｐ−ｔｅｒｔ−ブチルフェノール（０．２８３ｇ）、ベンジルトリエチルアンモニウムクロライド（０．０８３ｇ）および２，２−ビス（４−ヒドロキシ−３，５−ジメチルフェニル）プロパン［テトラメチルビスフェノールＡ］（１８．４８ｇ）の順に添加、撹拌した後、このアルカリ水溶液を１Ｌ反応槽に移した。
【００５７】
別途、テレフタル酸クロライド（４．０４ｇ）、テレフタル酸クロライド（９．４３ｇ）をジクロロメタン（３００ｍｌ）に溶解し滴下ロート内に移した。
重合槽の外温を２０℃に保ち、反応槽内のアルカリ水溶液を撹拌しながら、滴下ロートよりジクロロメタン溶液を１時間かけて滴下した。さらに３時間撹拌を続けた後、酢酸（２．２３ｍｌ）、ジクロロメタン（１５０ｍｌ）を加え３０分撹拌した。その後、撹拌を停止し有機層を分離した。この有機層を０．１Ｎ水酸化ナトリウム水溶液（８１０ｍｌ）にて洗浄を２回行い、次に０．１Ｎ塩酸（８１０ｍｌ）にて洗浄を２回行い、さらにＨ₂Ｏ（８１０ｍｌ）にて洗浄を２回行った。
【００５８】
洗浄後の有機層３００ｍｌをメタノール（１５００ｍｌ）に注いで得られた沈殿物を濾過にて取り出し、乾燥してポリアリレート樹脂Ｂを得た。得られたポリアリレート樹脂Ｂの粘度平均分子量は１２，４００であった。構造式を以下に示す。
【００５９】
【化７】

【００６０】
製造例３（比較例２のポリアリレート樹脂Ｃの製造法）
１Ｌビーカーに水酸化ナトリウム（５．８４ｇ）とＨ₂Ｏ（４００ｍｌ）を秤取り、窒素バブリングしながら撹拌し溶解させた。そこにｐ−ｔｅｒｔ−ブチルフェノール（０．２１７９ｇ）、ベンジルトリエチルアンモニウムクロライド（０．０６３６ｇ）および２，２−ビス（４−ヒドロキシフェニル）プロパン［ビスフェノールＡ］（１２．８３ｇ）の順に添加、撹拌した後、このアルカリ水溶液を１Ｌ反応槽に移した。
【００６１】
別途、テレフタル酸クロライド（１０．３７ｇ）をジクロロメタン（２００ｍｌ）に溶解し２００ｍｌ滴下ロート内に移した。
重合槽の外温を２０℃に保ち、反応槽内のアルカリ水溶液を撹拌しながら、滴下ロートよりジクロロメタン溶液を１時間かけて滴下した。滴下と共に反応槽内には不溶物の析出が見られた。滴下が進むにつれ不溶物の析出は増えていった。さらに３時間撹拌を続けた後、酢酸（２．６１１ｍｌ）、ジクロロメタン（１００ｍｌ）を加え３０分撹拌した。その後、撹拌を停止し有機層と不溶物を共に水槽から分離した。この有機層と不溶物を０．１Ｎ水酸化ナトリウム水溶液（４５０ｍｌ）にて洗浄を２回行い、次に０．１Ｎ塩酸（４５０ｍｌ）にて洗浄を２回行い、さらにＨ₂Ｏ（４５０ｍｌ）にて洗浄を２回行った。
【００６２】
洗浄後の有機層と不溶物をメタノール（１５００ｍｌ）に注いで得られた沈殿物を濾過にて取り出し、乾燥してポリアリレート樹脂Ｃを得た。得られたポリアリレート樹脂Ｃはジクロロメタンには不溶であり、粘度平均分子量の測定は出来なかった。構造式を以下に示す。
【００６３】
【化８】

【００６４】
製造例４（比較例３のポリアリレート樹脂Ｄの製造法）
１Ｌビーカーに水酸化ナトリウム（４．６２ｇ）とＨ₂Ｏ（４００ｍｌ）を秤取り、窒素バブリングしながら撹拌し溶解させた。そこにｐ−ｔｅｒｔ−ブチルフェノール（０．１９８７ｇ）、ベンジルトリエチルアンモニウムクロライド（０．０５８３ｇ）および１，１−ビス（４−ヒドロキシフェニル）シクロヘキサン［ビスフェノールＺ］（１１．７０ｇ）の順に添加、撹拌した後、このアルカリ水溶液を１Ｌ反応槽に移した。
【００６５】
別途、テレフタル酸クロライド（９．４６ｇ）をジクロロメタン（２００ｍｌ）に溶解し２００ｍｌ滴下ロート内に移した。
重合槽の外温を２０℃に保ち、反応槽内のアルカリ水溶液を撹拌しながら、滴下ロートよりジクロロメタン溶液を１時間かけて滴下した。滴下と共に反応槽内には不溶物の析出が見られた。滴下が進むにつれ不溶物の析出は増えていった。さらに３時間撹拌を続けた後、酢酸（１．３８６ｍｌ）、ジクロロメタン（１００ｍｌ）を加え３０分撹拌した。その後、撹拌を停止し有機層と不溶物を共に水槽から分離した。この有機層と不溶物を０．１Ｎ水酸化ナトリウム水溶液（４５０ｍｌ）にて洗浄を２回行い、次に０．１Ｎ塩酸（４５０ｍｌ）にて洗浄を２回行い、さらにＨ₂Ｏ（４５０ｍｌ）にて洗浄を２回行った。
【００６６】
洗浄後の有機層と不溶物をメタノール（１５００ｍｌ）に注いで得られた沈殿物を濾過にて取り出し、乾燥してポリアリレート樹脂Ｄを得た。得られたポリアリレート樹脂Ｄはジクロロメタンには不溶であり、粘度平均分子量の測定は出来なかった。構造式を以下に示す。
【００６７】
【化９】

【００６８】
＜感光体の製造＞
実施例１
下記構造を有するβ型オキシチタニウムフタロシアニン１０重量部を、４−メトキシ−４−メチルペンタノン−２ １５０重量部に加え、サンドグラインドミルにて粉砕分散処理を行った。
【００６９】
【化１０】

【００７０】
また、ポリビニルブチラール（電気化学工業（株）製、商品名デンカブチラール＃６０００Ｃ）の５％ １，２−ジメトキシエタン溶液１００部及びフェノキシ樹脂（ユニオンカーバイド社製、商品名ＰＫＨＨ）の５％ １，２−ジメトキシエタン溶液１００部を混合してバインダー溶液を作製した。
先に作製した顔料分散液１６０重量部に、バインダー溶液１００重量部、適量の１，２−ジメトキシエタンを加え最終的に固形分濃度４．０％の分散液を調製した。
【００７１】
この様にして得られた分散液を表面にアルミ蒸着したポリエチレンテレフタレートフィルム上に膜厚が０．４μｍになるように塗布して電荷発生層を設けた。
次にこのフィルム上に、次に示す正孔輸送性化合物［１］６０重量部、
【００７２】
【化１１】

【００７３】
および製造例１で製造した粘度平均分子量２３，２００のポリアリレート樹脂Ａ１００重量部、およびレベリング剤としてシリコーンオイル０．０３重量部をテトラヒドロフラン、トルエンの混合溶媒（テトラヒドロフラン８０ｗｔ％、トルエン２０ｗｔ％）６４０重量部に溶解させた液を塗布し、１２５℃で２０分間乾燥し、乾燥後の膜厚が２０μｍとなるように電荷輸送層を設けた。このときポリアリレート樹脂Ａのテトラヒドロフラン、トルエン混合溶媒に対する溶解性は良好であった。
【００７４】
比較例１
実施例１中のポリアリレート樹脂を、製造例２で製造した粘度平均分子量１２，４００のポリアリレート樹脂Ｂを用いた以外は、実施例１と同様の操作を行った。このときポリアリレート樹脂Ｂの溶解性は良好であった。
比較例２
実施例１中のポリアリレート樹脂を、製造例３で製造したポリアリレート樹脂Ｃを用いて実施しようとしたが、このときポリアリレート樹脂Ｃはテトラヒドロフラン、トルエン混合溶媒（テトラヒドロフラン８０ｗｔ％、トルエン２０ｗｔ％）には溶解せず、塗布液を作ることも、塗布することもできず、感光体を得ることはできなかった。
【００７５】
比較例３
実施例１中のポリアリレート樹脂を、製造例４で製造したポリアリレート樹脂Ｄを用いて実施しようとしたが、このときポリアリレート樹脂Ｄはテトラヒドロフラン、トルエン混合溶媒（テトラヒドロフラン８０ｗｔ％、トルエン２０ｗｔ％）には溶解せず、塗布液を作ることも、塗布することもできず、感光体を得ることはできなかった。
【００７６】
こうして得られた各感光体については以下の評価を行った。
［電気特性］
電子写真学会測定標準に従って作製された電子写真特性評価装置（続電子写真技術の基礎と応用、電子写真学会編、コロナ社、４０４−４０５頁記載）を使用し、上記感光体をアルミニウム製ドラムに貼り付けて円筒状にし、アルミニウム製ドラムと感光体のアルミニウム基体との導通を取った上で、ドラムを一定回転数で回転させ、帯電、露光、電位測定、除電のサイクルによる電気特性評価試験を行った。その再、初期表面電位を−７００Ｖとし、露光は７８０ｎｍ、除電は６６０ｎｍの単色光を用いた。評価項目としては、７８０ｎｍの光を２．４μＪ／ｃｍ²照射した時点の表面電位（ＶＬ）、および除電光照射後の残留電位（Ｖｒ）を測定した。ＶＬ測定に際しては、露光−電位測定に要する時間を１３９ｍｓとした。測定環境は、温度２５℃、相対湿度５０％下で行った。この表面電位（ＶＬ）の値の絶対値が小さいほど、応答性がよいことを示す。結果を表１に示す。
【００７７】
【表１】

【００７８】
以上の結果より、特定構造のポリアリレート樹脂は、非ハロゲン系溶媒にも高い溶解性を有し、これを用いることにより、電気特性、特に応答性に優れた電子写真感光体が得られることがわかる。
【００７９】
【発明の効果】
本発明の電子写真感光体樹脂は、特定構造のポリアリレート樹脂を用いることにより、十分な機械的特性を有し、非ハロゲン系溶媒にも高い溶解性を有し、且つ電気特性、特に応答性に優れる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photoreceptor.
More specifically, the present invention relates to an electrophotographic photosensitive member containing a resin for an electrophotographic photosensitive member that is excellent in solubility at the time of adjusting a coating solution and has good electrical response.
[0002]
[Prior art]
In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high quality images.
Photoconductors that are the core of electrophotographic technology have been used as conventional photoconductive materials for inorganic photoconductors such as selenium, arsenic-selenium alloys, cadmium sulfide, and zinc oxide. A photoreceptor using an organic photoconductive material having advantages such as easy and easy manufacture has been developed.
[0003]
As the organic photoreceptor, a so-called dispersion type photoreceptor in which a photoconductive fine powder is dispersed in a binder resin, and a laminate type photoreceptor in which a charge generation layer and a charge transfer layer are laminated are known. Laminated photoconductors can provide highly sensitive photoconductors by combining highly efficient charge generating materials and charge transfer materials, and can provide photoconductors with a wide range of material selection and high safety. Since it is highly productive and relatively advantageous in terms of cost, there is a high possibility that it will become the mainstream of photoconductors.
[0004]
Since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposure, development, transfer, cleaning, static elimination, and the like, it is deteriorated by various stresses during that time. Such deterioration includes, for example, strongly oxidative ozone and NOx generated from a corona charger normally used as a charger, which chemically damages the photosensitive layer, or a carrier (current) generated by image exposure is generated by the photosensitive layer. There are chemical and electrical degradations due to degradation of the photosensitive layer composition by flowing inside, static elimination light, and external light. Further, there is mechanical deterioration such as abrasion of the surface of the photosensitive layer due to rubbing of a cleaning blade, a magnetic brush or the like, contact with a developer, paper, and the like, and film peeling. In particular, such damage on the surface of the photosensitive layer is likely to appear on the copy image, and directly impairs the image quality, which is a major factor that limits the life of the photoreceptor. That is, in order to develop a long-life photoconductor, it is essential to increase the mechanical strength as well as the electrical and chemical durability.
[0005]
In general, a charge transfer layer is subjected to such a load in the case of a laminated type photoreceptor. The charge transfer layer is usually composed of a binder resin and a charge transfer material, and it is the binder resin that substantially determines the strength. However, since the amount of the charge transfer material doped is considerably large, sufficient mechanical strength has been reached. Not in.
In addition, due to the increasing demand for high-speed printing, materials for a higher-speed electrophotographic process are required. In this case, in addition to high sensitivity and long life, the photosensitive member must have good responsiveness because the time from exposure to development is shortened. It is known that the responsiveness of the photoreceptor is governed by the charge transfer layer, particularly the charge transfer substance, but also greatly changes depending on the binder resin.
[0006]
Conventional binder resins for charge transfer layers include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins. Various thermosetting resins have been used. Among the various binder resins, the polycarbonate resin has relatively excellent performance, and various polycarbonate resins have been developed and put into practical use. For example, JP-A-50-98332 discloses bisphenol P type polycarbonate, JP-A-59-71057 discloses bisphenol Z-type polycarbonate, JP-A-59-184251 discloses bisphenol P and bisphenol A. No. 5,21478 discloses a polycarbonate copolymer having a bis (4-hydroxyphenyl) ketone type structure as a binder resin. However, conventional organic photoreceptors have drawbacks such as surface wear and scratches caused by practical loads such as development with toner, friction with paper, and friction with a cleaning member (blade). Therefore, the current situation is that the printing performance is limited in practical use.
[0007]
On the other hand, Japanese Patent Laid-Open No. 56-135844 discloses a technique of an electrophotographic photoreceptor using a polyarylate resin having the following structure marketed under the trade name “U-polymer” as a binder. It has been shown that the sensitivity is particularly superior compared to polycarbonate.
Japanese Patent Laid-Open No. 10-28845 discloses that the use of a polyarylate resin using a bisphenol component having a specific structure as a binder resin improves the solution stability during the production of a photoreceptor. Japanese Patent No. 288846 discloses that an electrophotographic photosensitive member using a polyarylate resin having a specific kinematic viscosity range is excellent in mechanical strength, particularly wear resistance.
[0008]
[Problems to be solved by the invention]
However, when the currently used polycarbonate resin is used in the electrophotographic process, it is still often insufficient in terms of wear resistance, scratch resistance, responsiveness, adhesion to the substrate, and the like.
In addition, although the commercially available polyarylate resin “U-polymer” shows some improvement in abrasion resistance and sensitivity, the solubility during the production of the coating liquid is poor, and the coating production is impossible. Some polyarylate resins having a structure dissolve in halogenated hydrocarbons, but some non-halogen solvents such as tetrahydrofuran and 1,4-dioxane have low solubility and cannot be used to produce a coating solution.
[0009]
In addition, the use of a polyarylate resin having a specific structure disclosed in JP-A-10-288845 improves solubility and mechanical strength, but due to the recent increase in demand for high-speed printing, The characteristics, particularly responsiveness, were insufficient.
Therefore, at present, a binder resin that is easily soluble in a non-halogen solvent and excellent in responsiveness is desired.
[0010]
[Means for Solving the Problems]
Therefore, as a result of a detailed study of the binder resin used in the photosensitive layer, the present inventors have used polyarylate resin having a specific structure as the binder resin, so that it has high solubility in non-halogen solvents and is electrically It has been found that it has excellent characteristics, particularly responsiveness, and has led to the present invention.
[0011]
That is, the gist of the present invention is that, in an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the photosensitive layer has a repeating unit represented by the general formula (1).Contains 80% or moreAn electrophotographic photoreceptor comprising a polyarylate resin.
[0012]
[Chemical Formula 3]

[0013]
(In the general formula (1), R¹, R², R^Three, R^FourAnd R⁹Are each independently an alkyl group having 1 to 10 carbon atoms and an alkoxyl having 1 to 10 carbon atoms.GroupA rogenated alkyl group or an optionally substituted aromatic group having 6 to 20 carbon atoms is shown. R^Five, R⁶, R⁷, R⁸And R^TenEach independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a halogen, a halogenated alkyl group, or an aromatic group having 6 to 20 carbon atoms which may be substituted. R⁹And R^TenMay be bound to each other. )
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
<Polyarylate resin>
The electrophotographic photosensitive member of the present invention contains a polyarylate resin whose main component is a repeating unit represented by the general formula (1) in the photosensitive layer.
[0015]
Specific examples of the structure of the polyarylate resin represented by the general formula (1) include the following. In the general formula (1), R¹, R², R^Three, R^FourAnd R⁹Are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxyl having 1 to 4 carbon atoms.GroupRogenated alkyl group, which represents an optionally substituted aromatic group having 6 to 20 carbon atoms, R^Five, R⁶, R⁷, R⁸And R^TenEach independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a halogen, a halogenated alkyl group, or an optionally substituted aromatic group having 6 to 20 carbon atoms. The alkyl group having 1 to 6 carbon atoms is, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, or an n-benzyl group. , Sec-pentyl group, n-hexyl group and the like. Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, n-butoxy group and the like. Examples of the halogen include a chlorine atom, a bromine atom, and a fluorine atom, and examples of the halogenated alkyl group include a chloromethyl group, a dichloromethyl group, a trichloromethyl group, and a trifluoromethyl group. Examples of the aromatic group that may be substituted include a phenyl group, a 4-methylphenyl group, and a naphthyl group.
[0016]
Of these, preferably R¹, R², R^ThreeAnd R^FourAre each independently an alkyl group having 1 to 6 carbon atoms, and R^Five, R⁶, R⁷And R⁸Are each independently a hydrogen atom, R⁹And R^TenAre each independently an alkyl group having 1 to 6 carbon atoms.
Particularly preferably, R¹, R², R^Three, R^Four, R⁹And R^TenEach is a methyl group.
[0017]
The structure represented by the following general formula (3) in the general formula (1) is a residue derived from a bisphenol component used when producing the polyarylate resin used in the present invention.
[0018]
[Formula 4]

[0019]
Specific examples of the bisphenol component include 1,1-bis- (4-hydroxy-3,5-dimethylphenyl) ethane, 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane, bis ( 4-hydroxy-3,5-dimethylphenyl) phenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) diphenylmethane, 1,1-bis- (4-hydroxy-3,5-dimethylphenyl) phenylethane, 1,1-bis- (4-hydroxy-3,5-dimethylphenyl) cyclohexane, 1,1-bis- (4-hydroxy-3,5-di (t-butyl) phenyl) ethane, 2,2-bis -(4-hydroxy-3,5-di (t-butyl) phenyl) propane, bis- (4-hydroxy-3,5-di (t-butyl) phenyl) phenylme Bis- (4-hydroxy-3,5-di (t-butyl) phenyl) diphenylmethane, 1,1-bis- (4-hydroxy-3,5-di (t-butyl) phenyl) phenylethane, , 1-bis- (4-hydroxy-3,5-di (t-butyl) phenyl) cyclohexane, 1,1-bis- (4-hydroxy-2,3,5-trimethylphenyl) ethane, 2,2- Bis- (4-hydroxy-2,3,5-trimethylphenyl) propane, bis- (4-hydroxy-2,3,5-trimethylphenyl) phenylmethine, 1,1-bis- (4-hydroxy-2, 3,5-trimethylphenyl) phenylethane, 1,1-bis- (4-hydroxy-2,3,5-trimethylphenyl) cyclohexane, and the like. Among these, preferable examples include
1,1-bis- (4-hydroxy-3,5-dimethylphenyl) ethane, 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis- (4-hydroxy -3,5-dimethylphenyl) cyclohexane, 1,1-bis- (4-hydroxy-3,5-di (t-butyl) phenyl) ethane, 2,2-bis- (4-hydroxy-3,5- And di (t-butyl) phenyl) propane, 1,1-bis- (4-hydroxy-3,5-di (t-butyl) phenyl) cyclohexane, and the like. Of these, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane is particularly preferable.
<Method for producing polyarylate resin>
As a method for producing the resin for an electrophotographic photoreceptor of the present invention, a known polymerization method can be used. Examples thereof include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method.
[0020]
For example, in the case of production by an interfacial polymerization method, a solution in which a bifunctional phenol component or bisphenol component is dissolved in an alkaline aqueous solution and a halogenated hydrocarbon solution in which an aromatic dicarboxylic acid chloride component is dissolved are mixed. At this time, a quaternary ammonium salt or a quaternary phosphonium salt may be present as a catalyst. The polymerization temperature is usually in the range of 0 to 40 ° C., and the polymerization time is preferably in the range of 2 to 12 hours from the viewpoint of productivity. After completion of the polymerization, the water phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method, whereby the intended resin can be obtained.
[0021]
Examples of the alkali component used here include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide. As the usage-amount of an alkali, the range of 1.01-3 times equivalent of the phenolic hydroxyl group contained in a reaction system is preferable.
Examples of the halogenated hydrocarbon used here include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene, and the like.
[0022]
The quaternary ammonium salt or quaternary phosphonium salt used as a catalyst includes salts of tertiary alkylamines such as tributylamine and trioctylamine such as hydrochloric acid, bromic acid, iodic acid, benzyltriethylammonium chloride, benzyltrimethylammonium chloride, Examples include benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride.
[0023]
As the aromatic dicarboxylic acid chloride component, terephthalic acid chloride is mainly used.
Specific examples of the bisphenol component are as described above, and it is also possible to use one or two or more of the above compounds in combination.
In this polymerization, phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p-tert-butylphenol, pentyl are used as molecular weight modifiers. Phenol, hexylphenol, octylphenol, nonylphenol, alkylphenols such as 2,6-dimethylphenol, monofunctional phenols such as o, m, p-phenylphenol, acetic chloride, butyric chloride, octyl chloride, benzoyl chloride, benzene Monofunctional acid halides such as sulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride and their substituted products may be present.
[0024]
The polyarylate resin mainly composed of the repeating unit represented by the general formula (1) of the present invention has a viscosity average molecular weight of usually 10,000 to 300,000, preferably 15,000 to 100,000, more preferably 20,000 to 50,000. If the viscosity average molecular weight is too small, the mechanical strength of the resin is lowered and is not practical. If it is too large, it is difficult to apply the resin to an appropriate film thickness.
[0025]
Moreover, in the polyarylate resin having the repeating unit represented by the general formula (1) as a main component, “having the main component” means that the repeating unit of the general formula (1) contains 80% or more. Preferably 95% or more, particularly preferably 100%. If the number of repeating units is too small, the electrical characteristics, particularly the responsiveness, is not preferable. At this time, the groups present at the molecular chain terminals such as the molecular weight regulator described above are not included in the repeating unit.
[0026]
Further, the resin having a polyarylate structure of the present invention can be mixed with other resins and used for an electrophotographic photoreceptor. Other resins mixed here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins, Various thermosetting resins are exemplified. Among these resins, a polycarbonate resin is preferable.
<Electrophotographic photoreceptor>
The above-described resin of the present invention is used for an electrophotographic photoreceptor, and is used as a binder resin in a photosensitive layer provided on a conductive support of the photoreceptor.
[0027]
As the conductive support, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, nickel or the like, a resin material or aluminum provided with conductivity by adding conductive powder such as metal, carbon, tin oxide, Mainly used are resin, glass, paper, or the like, on which a conductive material such as nickel or ITO (indium tin oxide alloy) is deposited or coated. As a form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material in order to control conductivity and surface properties or to cover defects.
[0028]
When a metal material such as an aluminum alloy is used as the conductive support, it may be used after anodizing, chemical conversion coating or the like. When the anodizing treatment is performed, it is desirable to perform a sealing treatment by a known method.
The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support.
[0029]
An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties.
As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used.
Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. Only one type of particle may be used, or a plurality of types of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystalline state may be contained.
[0030]
In addition, various particle sizes of the metal oxide particles can be used. Among them, from the viewpoint of characteristics and liquid stability, the average temporary particle size is preferably 10 to 100 nm, particularly preferably 10 to 25 nm. It is.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As binder resin used for the undercoat layer, phenoxy, epoxy, polyvinyl pyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are used alone or in a cured form together with a curing agent. Among them, alcohol-soluble copolymerized polyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coating properties.
[0031]
The addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, but it is preferably used in the range of 10 to 500 wt% in terms of the stability of the dispersion and the coating property.
The thickness of the undercoat layer can be arbitrarily selected, but is preferably from 0.1 to 20 μm in view of the photoreceptor characteristics and coating properties. Moreover, you may add a well-known antioxidant etc. to an undercoat layer.
[0032]
As a specific constitution of the photosensitive layer of the present invention
A laminate type photoreceptor in which a charge generation layer mainly composed of a charge generation material, a charge transport layer material, and a charge transport layer mainly composed of a binder resin are laminated in this order on a conductive support.
A reverse two-layer type photoreceptor in which a charge transport layer mainly composed of a charge transport material and a binder resin and a charge generation layer composed mainly of a charge generation material are laminated in this order on a conductive support.
[0033]
A dispersion type photoreceptor in which a charge generation material is dispersed in a layer containing a charge transport material and a binder resin on a conductive support.
Such a configuration is given as an example of a basic shape.
In the case of a multilayer photoreceptor, charge generation materials used in the charge generation layer include, for example, selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments. In addition, it can be used in various photoconductive materials such as organic pigments such as polycyclic quinone pigments, anthanthrone pigments and benzimidazole pigments, and organic pigments, phthalocyanine pigments and azo pigments are particularly preferable. These fine particles are, for example, polyester resin, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polyester, polycarbonate, polyvinyl acetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester, cellulose ether, etc. It is used in a form bound with various binder resins. The use ratio in this case is used in the range of 30 to 500 parts by weight with respect to 100 parts by weight of the binder resin, and the film thickness is usually 0.1 μm to 1 μm, preferably 0.15 μm to 0.6 μm.
[0034]
When a phthalocyanine compound is used as the charge generation material, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide or halide thereof. Phthalocyanines are used. Examples of the ligand to a metal atom having 3 or more valences include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. Particularly preferred are X-type, τ-type metal-free phthalocyanine, titanyl phthalocyanine such as A-type, B-type, and D-type, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine. Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B type are described in W.W. It has been shown by Heller et al. As phase I and phase II (Zeit. Kristallodr. 159 (1982) 173), respectively, and type A is known as a stable type. The D type that is particularly preferably used is a crystal type characterized in that a diffraction angle 2θ ± 0.2 ° shows a clear peak at 27.3 ° in powder X-ray diffraction using CuKα rays. As the phthalocyanine compound, only a single compound may be used, or several mixed states may be used. As the mixed state that can be placed in the phthalocyanine compound or crystal state here, the respective constituent elements may be mixed and used later, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be generated. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.
[0035]
Examples of the charge transport material contained in the charge transport layer include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, and electron withdrawing materials such as quinones such as diphenoquinone, Carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, oxadiazole derivatives, pyrazoline derivatives, thiadiazole derivatives and other heterocyclic compounds, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine compounds And an electron donating substance such as a polymer in which a plurality of these compounds are bonded, or a polymer having a group composed of these compounds in the main chain or side chain. Among these, a carbazole derivative, a hydrazone derivative, an aromatic amine derivative, a stilbene derivative, a butadiene derivative, and a combination of these derivatives are preferable, and an aromatic amine derivative, a stilbene derivative, and a butadiene derivative are combined. preferable
Specifically, those having a structure represented by the following general formula (2) are preferably used.
[0036]
[Chemical formula 5]

[0037]
(In the general formula (2), Ar¹~ Ar^FourEach independently represents an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent. Ar^Five, Ar⁶Is m¹= 0, m²When = 0, each represents an alkyl group which may have a substituent, an aryl group which may have a substituent, a monovalent heterocyclic group which may have a substituent, m¹= 1, m²When = 1, each represents an alkylene group that may have a substituent, an arylene group that may have a substituent, or a divalent heterocyclic group that may have a substituent. Q represents a series bond or a divalent residue. R¹¹~ R¹⁸Each independently represents a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an aralkyl group which may have a substituent, or a complex which may have a substituent. N representing a cyclic group¹~ N^FourEach independently represents an integer of 0 to 4. M¹, M²Each independently represents 0 or 1. Ar¹~ Ar⁶May be bonded to each other to form a cyclic structure. )
More specifically, in the general formula (2), R¹¹~ R¹⁸Each independently has a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, a cyclopentyl group, and a cyclohexyl group. Of these, an alkyl group having 1 to 6 carbon atoms is preferred.
[0038]
Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a pyrenyl group, and an aryl group having 6 to 12 carbon atoms is preferable.
Examples of the aralkyl group include a benzyl group and a phenethyl group, and an aralkyl group having 7 to 12 carbon atoms is preferable.
The heterocyclic group is preferably an aromatic heterocyclic ring, and examples thereof include a furyl group, a thienyl group, and a pyridyl group, and a monocyclic aromatic heterocyclic ring is more preferable.
[0039]
R¹¹~ R¹⁸And most preferred are a methyl group and a phenyl group.
In the general formula (2), Ar¹~ Ar^FourEach independently represents an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent, and Ar^Five, Ar⁶Is m¹= 0, m²= 0 represents an alkyl group which may have a substituent, an aryl group which may have a substituent, and a monovalent heterocyclic group which may have a substituent, m¹= 1, m²When = 1, each represents an alkylene group that may have a substituent, an arylene group that may have a substituent, or a divalent heterocyclic group that may have a substituent. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a pyrenyl group, and an aryl group having 6 to 14 carbon atoms is preferable; examples of the arylene group include a phenylene group and a naphthylene group. A phenylene group is preferable; the monovalent heterocyclic group is preferably an aromatic heterocyclic ring, and examples thereof include a furyl group, a thienyl group, and a pyridyl group, and a monocyclic aromatic heterocyclic ring is more preferable; The valent heterocyclic group is preferably an aromatic heterocyclic ring, and examples thereof include a pyridylene group and a thienylene group, and a monocyclic aromatic heterocyclic ring is more preferable.
[0040]
Of these, the most preferred is Ar¹And Ar²Is a phenylene group and Ar^ThreeIs a phenyl group.
These R¹¹~ R¹⁸, Ar¹~ Ar⁶Among these groups, the alkyl group, aryl group, aralkyl group, and heterocyclic group may further have a substituent, and examples of the substituent include cyano group; nitro group; hydroxyl group; fluorine atom, Halogen atoms such as chlorine atom, bromine atom and iodine atom; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, cyclopentyl group, Alkyl groups such as cyclohexyl groups; alkoxy groups such as methoxy groups, ethoxy groups, and propyloxy groups; alkylthio groups such as methylthio groups and ethylthio groups; alkenyl groups such as vinyl groups and allyl groups; benzyl groups, naphthylmethyl groups, and phenethyl groups Aralkyl groups such as phenoxy groups, aryloxy groups such as triloxy groups; benzyloxy groups, phenethyloxy groups, etc. Arylalkoxy groups; aryl groups such as phenyl groups and naphthyl groups; arylvinyl groups such as styryl groups and naphthylvinyl groups; acyl groups such as acetyl groups and benzoyl groups; dialkylamino groups such as dimethylamino groups and diethylamino groups; Groups, diarylamino groups such as dinaphthylamino groups; diaralkylamino groups such as dibenzylamino groups and diphenethylamino groups; diheterocyclic amino groups such as dipyridylamino groups and dithienylamino groups; diallylamino groups; Examples thereof include substituted amino groups such as disubstituted amino groups in which the above amino group substituents are combined.
[0041]
These substituents may be bonded to each other to form a cyclic hydrocarbon group or a heterocyclic group via a single bond, a methylene group, an ethylene group, a carbonyl group, a vinylidene group, an ethylenylene group or the like.
Among these, preferred substituents are halogen atoms, cyano groups, hydroxyl groups, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, alkylthio groups having 1 to 6 carbon atoms, and 6 to 12 carbon atoms. An aryloxy group, an arylthio group having 6 to 12 carbon atoms, and a dialkylamino group having 2 to 8 carbon atoms are exemplified. A halogen atom, an alkyl group having 1 to 6 carbon atoms, and a phenyl group are more preferable, and a methyl group and a phenyl group are preferable. Particularly preferred.
[0042]
In general formula (2), n¹~ N^FourEach independently represents an integer of 0 to 4, preferably 0 to 2, and most preferably 1. m¹, M²Represents 0 or 1, with 0 being preferred.
In general formula (2), Q represents a direct bond or a divalent residue, but a divalent residue is preferably a group 16 atom, an alkylene which may have a substituent, or a substituent. An arylene group that may be substituted, a cycloalkylidene group that may have a substituent, or a group in which these are bonded to each other, such as [—O—A—O—], [—A—O—A—], [—S -AS-], [-AA-], etc. are mentioned (however, A represents an arylene group which may have a substituent or an alkylene group which may have a substituent).
As an alkylene group which comprises Q, a C1-C6 thing is preferable and a methylene group and an ethylene group are still more preferable especially. Moreover, as a cycloalkylidene group, a C5-C8 thing is preferable and a cyclopentylidene group and a cyclohexylidene group are still more preferable especially. As the arylene group, those having 6 to 14 carbon atoms are preferable, and among them, a phenylene group and a naphthylene group are more preferable.
[0043]
These alkylene groups, arylene groups, and cycloalkylidene groups may have a substituent. Preferred substituents include a hydroxyl group, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 6 carbon atoms, carbon A C1-C6 alkenyl group and a C6-C14 aryl group are mentioned.
These charge transport materials may be used alone or in combination. The charge transport layer is formed in such a form that these charge transport materials are bound to the binder resin. The charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different constituent components or composition ratios.
[0044]
The ratio of the binder resin to the charge transport material is usually 30 to 200 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The film thickness is generally 5 to 50 μm, preferably 10 to 45 μm.
The charge transport layer has well-known plasticizers, antioxidants, ultraviolet absorbers, electron withdrawing properties to improve film forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. You may contain additives, such as a compound and a leveling agent.
[0045]
Examples of the antioxidant include hindered phenol compounds and hindered amine compounds.
In the case of a dispersion-type photosensitive layer, the above-described charge generating material is dispersed in the charge transport medium having the above-described blending ratio.
In this case, the particle size of the charge generating material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are adverse effects such as reduced chargeability and reduced sensitivity, for example, preferably 0.5 to 50 weights. %, More preferably 1 to 20% by weight.
[0046]
The film thickness of the photosensitive layer is usually 5 to 50 μm, more preferably 10 to 45 μm. Also in this case, known plasticizers for improving film formability, flexibility, mechanical strength, additives for suppressing residual potential, dispersion aids for improving dispersion stability, coatability A leveling agent and a surfactant, for example, silicone oil, fluorine-based oil and other additives may be added to improve the above.
[0047]
A protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge product generated from a charger or the like.
Further, for the purpose of reducing frictional resistance and wear on the surface of the photoreceptor, the surface layer may contain a fluorine-based resin, a silicone resin, or the like. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.
[0048]
Each layer constituting these photoreceptors is formed on the support by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating or the like.
As a method for forming each layer, a known method such as sequentially applying a coating solution obtained by dissolving or dispersing a substance contained in a layer in a solvent can be applied.
[0049]
An electrophotographic apparatus such as a copying machine or a printer using the electrophotographic photosensitive member of the present invention includes at least each process of charging, exposure, development, and transfer, and any process that is usually used may be used. . As a charging method (charger), for example, corotron or scorotron charging using corona discharge, contact charging with a conductive roller, brush, film or the like may be used. Of these, in the charging method using corona discharge, scoroton charging is often used to keep the dark portion potential constant. As a developing method, a general method of developing by bringing a magnetic or non-magnetic one-component developer or two-component developer into contact or non-contact is used. As a transfer method, any method using a corona discharge, a method using a transfer roller or a transfer belt may be used. The transfer may be performed directly on paper, an OHP film, or the like, or may be transferred to an intermediate transfer body (belt shape or drum shape) and then transferred onto paper or an OHP film.
[0050]
Usually, after the transfer, a fixing process for fixing the developer onto paper or the like is used, and as the fixing means, commonly used thermal fixing, pressure fixing, or the like can be used. In addition to these processes, processes such as normally used cleaning and static elimination may be provided.
[0051]
【Example】
Hereinafter, specific embodiments of the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples unless it exceeds the gist.
<Manufacture of polyarylate resin>
[Viscosity average molecular weight]
Polyarylate resin was dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Flow time t of solvent (dichloromethane)₀Was measured using a Ubbelohde capillary viscometer of 136.16 seconds in a constant temperature water bath set at 20.0 ° C. The viscosity average molecular weight Mv was calculated according to the following formula.
[0052]
[Expression 1]
a = 0.438 × η_sp+1 η_sp= T / t₀-1
b = 100 × η_sp/ C C = 6.00 (g / L)
η = b / a
Mv = 3207 × η^1.205
Production Example 1 (Production Method of Polyarylate Resin A of Example 1)
Sodium hydroxide (4.51g) and H in a 1L beaker₂O (400 ml) was weighed and dissolved by stirring with nitrogen bubbling. Thereto p-tert-butylphenol (0.33 g), benzyltriethylammonium chloride (0.0567 g) and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane [tetramethylbisphenol A] (11. After adding and stirring in the order of 99 g), the aqueous alkaline solution was transferred to a 1 L reaction vessel.
[0053]
Separately, terephthalic acid chloride (8.80 g) was dissolved in dichloromethane (200 ml) and transferred into a 200 ml dropping funnel.
While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the aqueous alkali solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (1.49 ml) and dichloromethane (100 ml) were added and stirred for 30 minutes. Then, stirring was stopped and the organic layer was separated. This organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (226 ml), then washed twice with 0.1N hydrochloric acid (226 ml), and further washed with H₂Washing was performed twice with O (226 ml).
[0054]
The washed organic layer was poured into methanol (1500 ml), and the resulting precipitate was removed by filtration and dried to obtain the desired polyarylate resin A. The resulting polyarylate resin A had a viscosity average molecular weight of 23,200. The structural formula is shown below.
[0055]
[Chemical 6]

[0056]
Production Example 2 (Production Method of Polyarylate Resin B of Comparative Example 1)
In a 1 L beaker, sodium hydroxide (6.77 g) and H₂O (600 ml) was weighed and dissolved by stirring with nitrogen bubbling. Thereto, p-tert-butylphenol (0.283 g), benzyltriethylammonium chloride (0.083 g) and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane [tetramethylbisphenol A] (18. After adding and stirring in the order of 48 g), the aqueous alkaline solution was transferred to a 1 L reaction vessel.
[0057]
Separately, terephthalic acid chloride (4.04 g) and terephthalic acid chloride (9.43 g) were dissolved in dichloromethane (300 ml) and transferred into a dropping funnel.
While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the aqueous alkali solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (2.23 ml) and dichloromethane (150 ml) were added and stirred for 30 minutes. Then, stirring was stopped and the organic layer was separated. This organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (810 ml), then washed twice with 0.1N hydrochloric acid (810 ml), and further washed with H₂Washing was performed twice with O (810 ml).
[0058]
A precipitate obtained by pouring 300 ml of the washed organic layer into methanol (1500 ml) was taken out by filtration and dried to obtain polyarylate resin B. The resulting polyarylate resin B had a viscosity average molecular weight of 12,400. The structural formula is shown below.
[0059]
[Chemical 7]

[0060]
Production Example 3 (Production Method of Polyarylate Resin C of Comparative Example 2)
In a 1 L beaker, sodium hydroxide (5.84 g) and H₂O (400 ml) was weighed and dissolved by stirring with nitrogen bubbling. Thereto, p-tert-butylphenol (0.2179 g), benzyltriethylammonium chloride (0.0636 g) and 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] (12.83 g) were added and stirred in this order. Thereafter, this aqueous alkaline solution was transferred to a 1 L reaction vessel.
[0061]
Separately, terephthalic acid chloride (10.37 g) was dissolved in dichloromethane (200 ml) and transferred into a 200 ml dropping funnel.
While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the aqueous alkali solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. Along with the dropwise addition, insoluble matter was precipitated in the reaction vessel. As instillation progressed, the precipitation of insoluble matter increased. After further stirring for 3 hours, acetic acid (2.611 ml) and dichloromethane (100 ml) were added and stirred for 30 minutes. Then, stirring was stopped and both the organic layer and the insoluble material were separated from the water tank. This organic layer and insoluble matter were washed twice with 0.1N sodium hydroxide aqueous solution (450 ml), then washed twice with 0.1N hydrochloric acid (450 ml), and further washed with H₂Washing was performed twice with O (450 ml).
[0062]
The washed organic layer and insoluble matter were poured into methanol (1500 ml), and the resulting precipitate was filtered off and dried to obtain polyarylate resin C. The resulting polyarylate resin C was insoluble in dichloromethane, and the viscosity average molecular weight could not be measured. The structural formula is shown below.
[0063]
[Chemical 8]

[0064]
Production Example 4 (Production Method of Polyarylate Resin D of Comparative Example 3)
In a 1L beaker, sodium hydroxide (4.62g) and H₂O (400 ml) was weighed and dissolved by stirring with nitrogen bubbling. Thereto were added p-tert-butylphenol (0.1987 g), benzyltriethylammonium chloride (0.0583 g) and 1,1-bis (4-hydroxyphenyl) cyclohexane [bisphenol Z] (11.70 g) in this order and stirred. Thereafter, this aqueous alkaline solution was transferred to a 1 L reaction vessel.
[0065]
Separately, terephthalic acid chloride (9.46 g) was dissolved in dichloromethane (200 ml) and transferred into a 200 ml dropping funnel.
While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the aqueous alkali solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. Along with the dropwise addition, insoluble matter was precipitated in the reaction vessel. As instillation progressed, the precipitation of insoluble matter increased. After further stirring for 3 hours, acetic acid (1.386 ml) and dichloromethane (100 ml) were added and stirred for 30 minutes. Then, stirring was stopped and both the organic layer and the insoluble material were separated from the water tank. This organic layer and insoluble matter were washed twice with 0.1N sodium hydroxide aqueous solution (450 ml), then washed twice with 0.1N hydrochloric acid (450 ml), and further washed with H₂Washing was performed twice with O (450 ml).
[0066]
The washed organic layer and insoluble matter were poured into methanol (1500 ml), and the resulting precipitate was filtered off and dried to obtain polyarylate resin D. The resulting polyarylate resin D was insoluble in dichloromethane, and the viscosity average molecular weight could not be measured. The structural formula is shown below.
[0067]
[Chemical 9]

[0068]
<Manufacture of photoconductor>
Example 1
10 parts by weight of β-type oxytitanium phthalocyanine having the following structure was added to 150 parts by weight of 4-methoxy-4-methylpentanone-2, and pulverized and dispersed in a sand grind mill.
[0069]
[Chemical Formula 10]

[0070]
In addition, 5% of 5% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name Denkabutyral # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 5% of phenoxy resin (trade name PKHH, manufactured by Union Carbide) 1, A binder solution was prepared by mixing 100 parts of a 2-dimethoxyethane solution.
100 parts by weight of the binder solution and an appropriate amount of 1,2-dimethoxyethane were added to 160 parts by weight of the previously prepared pigment dispersion to finally prepare a dispersion having a solid content concentration of 4.0%.
[0071]
The dispersion thus obtained was applied onto a polyethylene terephthalate film having aluminum deposited on the surface so as to have a film thickness of 0.4 μm to provide a charge generation layer.
Next, on this film, 60 parts by weight of the following hole transporting compound [1],
[0072]
Embedded image

[0073]
100 parts by weight of the polyarylate resin A having a viscosity average molecular weight of 23,200 produced in Production Example 1 and 0.03 parts by weight of silicone oil as a leveling agent are mixed with tetrahydrofuran and toluene in a mixed solvent (tetrahydrofuran 80 wt%, toluene 20 wt%) 640 wt. The solution dissolved in the part was applied, dried at 125 ° C. for 20 minutes, and a charge transport layer was provided so that the film thickness after drying was 20 μm. At this time, the solubility of polyarylate resin A in tetrahydrofuran and toluene mixed solvent was good.
[0074]
Comparative Example 1
The same operation as in Example 1 was performed except that the polyarylate resin in Example 1 was the polyarylate resin B having a viscosity average molecular weight of 12,400 produced in Production Example 2. At this time, the solubility of the polyarylate resin B was good.
Comparative Example 2
The polyarylate resin in Example 1 was tried to be carried out using the polyarylate resin C produced in Production Example 3. At this time, the polyarylate resin C was a tetrahydrofuran / toluene mixed solvent (tetrahydrofuran 80 wt%, toluene 20 wt%). Thus, it was impossible to make or apply a coating solution, and a photoconductor could not be obtained.
[0075]
Comparative Example 3
The polyarylate resin in Example 1 was tried to be carried out using the polyarylate resin D produced in Production Example 4. At this time, the polyarylate resin D was tetrahydrofuran / toluene mixed solvent (tetrahydrofuran 80 wt%, toluene 20 wt%). Thus, it was impossible to make or apply a coating solution, and a photoconductor could not be obtained.
[0076]
Each photoreceptor thus obtained was evaluated as follows.
[Electrical characteristics]
Using an electrophotographic characteristic evaluation apparatus (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404-405) prepared according to the Electrophotographic Society measurement standard, the photoconductor is made into an aluminum drum. Attached to a cylindrical shape, the aluminum drum and the aluminum base of the photoconductor are connected, and then the drum is rotated at a constant rotational speed, and an electrical property evaluation test is performed by a cycle of charging, exposure, potential measurement, and static elimination. went. Again, the initial surface potential was -700 V, monochromatic light of 780 nm for exposure and 660 nm for charge removal was used. As an evaluation item, 780 nm light is 2.4 μJ / cm.²The surface potential (VL) at the time of irradiation and the residual potential (Vr) after the neutralizing light irradiation were measured. In the VL measurement, the time required for the exposure-potential measurement was set to 139 ms. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50%. The smaller the absolute value of the surface potential (VL) value, the better the response. The results are shown in Table 1.
[0077]
[Table 1]

[0078]
From the above results, the polyarylate resin having a specific structure has high solubility in a non-halogen solvent, and by using this, an electrophotographic photoreceptor excellent in electrical characteristics, in particular, responsiveness can be obtained. Recognize.
[0079]
【The invention's effect】
By using a polyarylate resin having a specific structure, the electrophotographic photoreceptor resin of the present invention has sufficient mechanical properties, high solubility in non-halogen solvents, and electrical properties, particularly responsiveness. Excellent.

Claims (8)

An electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, wherein the photosensitive layer contains a polyarylate resin containing 80% or more of the repeating unit represented by the general formula (1). Electrophotographic photoreceptor.

(In the general formula ^{(1), R 1, R} 2, R 3, R 4 and R ⁹ each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, halogenation alkyl group, Or an optionally substituted aromatic group having 6 to 20 carbon atoms, wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ¹⁰ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, carbon An alkoxyl group having 1 to 10 carbon atoms, a halogen, a halogenated alkyl group, or an aromatic group having 6 to 20 carbon atoms which may be substituted, and R ⁹ and R ¹⁰ may be bonded to each other. The electrophotographic photosensitive member according to claim 1, wherein, in the general formula (1), R ¹ , R ² , R ³ and R ⁴ are methyl groups, and R ⁵ , R ⁶ , R ⁷ and R ⁸ are hydrogen atoms. The electrophotographic photosensitive member according to claim 2, wherein R ⁹ and R ^{10 in the} general formula (1) are each a methyl group.   The electrophotographic photosensitive member according to claim 1, wherein the polyarylate resin represented by the general formula (1) has a viscosity average molecular weight of 15,000 to 100,000.   The photosensitive layer contains at least one selected from the group consisting of a carbazole derivative, a hydrazone derivative, an aromatic amine derivative, a stilbene derivative, a butadiene derivative, and a combination of these derivatives as a charge transport material. 4. The electrophotographic photosensitive member according to any one of 4 above.   6. The electrophotographic photosensitive member according to claim 5, wherein the charge transport material is formed by bonding a plurality of aromatic amine derivatives, stilbene derivatives, and butadiene derivatives. The electrophotographic photosensitive member according to claim 6, wherein the charge transport material contains a material having a structure represented by the following general formula (2).

(In the general formula (2), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent. Ar ⁵ , Ar ⁶ is an alkyl group that may have a substituent, an aryl group that may have a substituent, or a monovalent group that may have a substituent when m ¹ = 0 and m ² = 0, respectively. And when m ¹ = 1 and m ² = 1, each may have an alkylene group which may have a substituent, an arylene group which may have a substituent, or a substituent. Represents a divalent heterocyclic group, Q represents a direct bond or a divalent residue, and R ^{11 to} R ¹⁸ each independently have a hydrogen atom, an alkyl group which may have a substituent, or a substituent. An aryl group that may be substituted, an aralkyl group that may have a substituent, and a heterocyclic group that may have a substituent, n ^{1 to} n ⁴ are each independently an integer of 0 to 4 M ¹ and m ² each independently represents 0 or 1. Ar ^{1 to} Ar ⁶ may be bonded to each other to form a cyclic structure.)   The photosensitive layer contains oxytitanium phthalocyanine having a main peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα rays as a charge generating material. An electrophotographic photoreceptor according to any one of the above.