JP3730025B2 - Organic photoconductive compound and electrophotographic photoreceptor using the same - Google Patents

Description

【００１４】
【化４】

【００１５】
一般式（１）或いは（２）において、Ｘは酸素原子、または硫黄原子を示し、Ｒ ₁ 、及びＲ ₂ は水素原子、低級アルキル基、低級アルコキシ基、またはハロゲン原子を示し、Ｒ ₃ は水素原子、置換基を有していてもよいアルキル基、アラルキル基、アリール基、または複素環を示す。Ａｒ ₁ は置換基を有していてもよいアリール基、または複素環を示す。
【００１６】
ここで、Ｘの具体例としては、酸素原子、または硫黄原子があげられる。
【００１７】
また、Ｒ ₁ 、Ｒ ₂ の具体例としては、水素原子、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基などの低級アルキル基、メトキシ基、エトキシ基、ｎ−プロポキシ基、ｎ−ブトキシ基などの低級アルコキシ基、またはフッ素原子、塩素原子、臭素原子などのハロゲン原子などを挙げることができる。
【００１８】
また、Ｒ ₃ の具体例としては、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、ｎ−ヘキシル基、ｎ−オクチル基、２−エチルヘキシル基、３−メトキシプロピル基、２−クロル−３−メチルヘキシル基などの無置換或いは置換アルキル基、ベンジル基、フェネチル基、３−フェニルプロピル基、ｐ−メチルベンジル基、ｏ−メトキシベンジル基、３，５−ジクロルベンジル基、２，４−ジメチルフェネチル基、ｐ−メトキシフェネチル基、２−メチル−３−フェニルプロピル基などの無置換或いは置換アラルキル基、フェニル基、ｐ−トリル基、ｍ−トリル基、ｐ−メトキシフェニル基、ｏ−メトキシフェニル基、ｐ−クロルフェニル基、３，５−ジメチルフェニル基、４−メトキシ−２−クロルフェニル基、３，５−ジメトキシフェニル基、１−ナフチル基、１−メチル−２−ナフチル基、９−フェナントリル基、１−ピレニル基などの無置換或いは置換アリール基、または２−フリル基、２−チエニル基、２−ピリジル基、２，６−ジメチル−４−ピリジル基、３−インドリル基、２−キノリル基などの無置換或いは置換複素環基など を挙げることができる。
【００１９】
また、Ａｒ ₁ の具体例としては、フェニル基、ｐ−トリル基、ｍ−トリル基、ｐ−メトキシフェニル基、ｏ−メトキシフェニル基、ｐ−クロルフェニル基、３，５−ジメチルフェニル基、４−メトキシ−２−クロルフェニル基、３，５−ジメトキシフェニル基、１−ナフチル基、１−メチル−２−ナフチル基、９−フェナントリル基、１−ピレニル基などの無置換或いは置換アリール基、２−フリル基、２−チエニル基、２−ピリジル基、２，６−ジメチル−４−ピリジル基、３−インドリル基、２−キノリル基などの無置換或いは置換複素環基などを挙げることができる。
【００２０】
【発明の実施の形態】
本発明にかかわる一般式（１）、または（２）で示される有機光導電性化合物の具体例としては、以下に示すＥＡ−０１〜２０のビススチルベン系化合物を挙げることができるが、これらに限定されるものではない。
【００２１】
【化５】

【００２２】
【化６】

【００２３】
【化７】

【００２４】
【化８】

【００２５】
本発明の、一般式（１）〜（２）で示される有機光導電性化合物を含有する感光層を含む電子写真感光体の形態は、そのいずれを用いることもできる。例えば、導電性支持体上に電荷発生物質、電荷輸送物質、及びフィルム形成性結着剤樹脂からなる感光層を設けたものがある。また、導電性支持体上に、電荷発生物質と結着剤樹脂からなる電荷発生層と、電荷輸送物質と結着剤樹脂からなる電荷輸送層を設けた積層型の感光体も知られている。電荷発生層と電荷輸送層はどちらが上層となっても構わない。また、必要に応じて導電性支持体と感光層の間に下引き層を、感光体表面にオーバーコート層を、積層型感光体の場合は電荷発生層と電荷輸送層との間に中間層を設けることもできる。本発明の化合物を用いて感光体を作製する支持体としては、金属製ドラム、金属板、導電性加工を施した紙やプラスチックフィルムのシート状、ドラム状あるいはベルト状の支持体などが使用される。
【００２６】
本発明の電子写真感光体は、一般式（１）〜（２）で示される有機光導電性化合物、及び電荷発生物質をそれぞれ１種類あるいは２種類以上含有することにより得られる。電荷発生物質には無機系電荷発生物質と有機系電荷発生物質があり、前者の例としては例えばセレン、セレン−テルル合金、セレン−ヒ素合金、硫化カドミウム、酸化亜鉛、アモルファスシリコンなどが挙げられる。有機系電荷発生物質の例としては、例えばメチルバイオレット、ブリリアントグリーン、クリスタルバイオレットなどのトリフェニルメタン系染料、メチレンブルーなどのチアジン染料、キニザリンなどのキノン染料、シアニン染料、アクリジン染料、ピリリウム色素、チアピリリウム色素、スクエアリウム色素、ペリノン系顔料、アントラキノン系顔料、ペリレン系顔料、金属含有あるいは無金属のフタロシア ニン系顔料などが挙げられ、また、アゾ顔料も用いられる。
【００２７】
アゾ顔料としては、例えば特開昭４７−３７５４３号公報、特開昭５３−９５０３３号公報、特開昭５３−１３２３４７号公報、特開昭５３−１３３４４５号公報、特開昭５４−１２７４２号公報、特開昭５４−２０７３６号公報、特開昭５４−２０７３７号公報、特開昭５４−２１７２８号公報、特開昭５４−２２８３４号公報、特開昭５５−６９１４８号公報、特開昭５５−６９６５４号公報、特開昭５５−７９４４９号公報、特開昭５５−１１７１５１号公報、特開昭５６−４６２３７号公報、特開昭５６−１１６０３９号公報、特開昭５６−１１６０４０号公報、特開昭５６−１１９１３４号公報、特開昭５６−１４３４３７号公報、特開昭５７−６３５３７号公報、特開昭５７−６３５３８号公報、特開昭５７−６３５４１号公報、特開昭５７−６３５４２号公報、特開昭５７−６３５４９号公報、特開昭５７−６６４３８号公報、特開昭５７−７４７４６号公報、特開昭５７−７８５４２号公報、特開昭５７−７８５４３号公報、特開昭５７−９００５６号公報、特開昭５７−９００５７号公報、特開昭５７−９０６３２号公報、特開昭５７−１１６３４５号公報、特開昭５７−２０２３４９号公報、特開昭５８−４１５１号公報、特開昭５８−９０６４４号公報、特開昭５８−１４４３５８号公報、特開昭５８−１７７９５５号公報、特開昭５９−３１９６２号公報、特開昭５９−３３２５３号公報、特開昭５９−７１０５９号公報、特開昭５９−７２４４８号公報、特開昭５９−７８３５６号公報、特開昭５９−１３６３５１号公報、特開昭５９−２０１０６０号公報、特開昭６０−１５６４２号公報、特開昭６０−１４０３５１号公報、特開昭６０−１７９７４６号公報、特開昭６１−１１７５４号公報、特開昭６１−９０１６４号公報、特開昭６１−９０１６５号公報、特開昭６１−９０１６６号公報、特開昭６１−１１２１５４号公報、特開昭６１−２６９１６５号公報、特開昭６１−２８１２４５号公報、特開昭６１−５１０６３号公報、特開昭６２−２６７３６３号公報、特開昭６３−６８８４４号公報、特開昭６３−８９８６６号公報、特開昭６３−１３９３５５号公報、特開昭６３−１４２０６３号公報、特開昭６３−１８３４５０号公報、特開昭６３−２８２７４３号公報、特開昭６４−２１４５５号公報、特開昭６４−７８２５９号公報、特開平１−２００２６７号公報、特開平１−２０２７５７号公報、特開平１−３１９７５４号公報、特開平２−７２３７２号公報、特開平２−２５４４６７号公報、特開平３−９５５６１号公報、特開平３−２７８０６３号公報、特開平４−９６０６８号公報、特開平４−９６０６９号公報、特開平４−１４７２６５号公報、特開平５−１４２８４１号公報、特開平５−３０３２２６号公報、特開平６−３２４５０４号公報、特開平７−１６８３７９号公報などに記載の化合物が挙げられる。
【００２８】
また、これらのアゾ顔料に用いられるカプラー成分の構造は多岐に渡る。例えば特開昭５４−１７７３５号公報、特開昭５４−７９６３２号公報、特開昭５７−１７６０５５号公報、特開昭５９−１９７０４３号公報、特開昭６０−１３０７４６号公報、特開昭６０−１５３０５０号公報、特開昭６０−１０３０４８号公報、特開昭６０−１８９７５９号公報、特開昭６３−１３１１４６号公報、特開昭６３−１５５０５２号公報、特開平２−１１０５６９号公報、特開平４−１４９４４８号公報、特開平６−２７７０５号公報、特開平６−３４８０４７号公報などに記載の化合物が挙げられる。
【００２９】
上記アゾ顔料の具体例としては、以下の表１〜４５に示す化合物を挙げることができるが、これらに限定されるものではない。また、これらの化合物と他の電荷発生物質を併用することも可能である。
【００３０】
【表１】

【００３１】
【表２】

【００３２】
【表３】

【００３３】
【表４】

【００３４】
【表５】

【００３５】
【表６】

【００３６】
【表７】

【００３７】
【表８】

【００３８】
【表９】

【００３９】
【表１０】

【００４０】
【表１１】

【００４１】
【表１２】

【００４２】
【表１３】

【００４３】
【表１４】

【００４４】
【表１５】

【００４５】
【表１６】

【００４６】
【表１７】

【００４７】
【表１８】

【００４８】
【表１９】

【００４９】
【表２０】

【００５０】
【表２１】

【００５１】
【表２２】

【００５２】
【表２３】

【００５３】
【表２４】

【００５４】
【表２５】

【００５５】
【表２６】

【００５６】
【表２７】

【００５７】
【表２８】

【００５８】
【表２９】

【００５９】
【表３０】

【００６０】
【表３１】

【００６１】
【表３２】

【００６２】
【表３３】

【００６３】
【表３４】

【００６４】
【表３５】

【００６５】
【表３６】

【００６６】
【表３７】

【００６７】
【表３８】

【００６８】
【表３９】

【００６９】
【表４０】

【００７０】
【表４１】

【００７１】
【表４２】

【００７２】
【表４３】

【００７３】
【表４４】

【００７４】
【表４５】

【００７５】
本発明において使用するフタロシアニン系顔料としては、それ自体公知のフタロシアニン及びその誘導体のいずれでも使用でき、具体的には、無金属フタロシアニン類、チタニルオキシフタロシアニン類、銅フタロシアニン類、アルミニウムフタロシアニン類、ジフェノキシゲルマニウムフタロシアニン類、ゲルマニウムフタロシアニン類、ガリウムフタロシアニン類、クロルガリウムフタロシアニン類、ブロムガリウムフタロシアニン類、クロルインジウムフタロシアニン類、ブロムインジウムフタロシアニン類、ヨードインジウムフタロシアニン類、マグネシウムフタロシアニン類、クロルアルミニウムフタロシアニン類、ブロムアルミニウムフタロシアニン類、スズフタロシアニン類、ジクロルスズフタロシアニン類、バナジルオキシフタロシアニン類、亜鉛フタロシアニン類、コバルトフタロシアニン類、ニッケルフタロシアニン類、ヒドロキシガリウムフタロシアニン類、ジヒドロキシガリウムフタロシアニン類、バリウムフタロシアニン類、ベリリウムフタロシアニン類、カドミウムフタロシアニン類、クロルコバルトフタロシアニン類、ジクロルチタニルフタロシアニン類、鉄フタロシアニン類、シリコンフタロシアニン類、鉛フタロシアニン類、白金フタロシアニン類、無金属ナフタロシアニン類、アルミニウムナフタロシアニン類、チタニルオキシナフタロシアニン類、ルテニウムフタロシアニン、パラジウムフタロシアニンなどが挙げられる。特にその中でも無金属フタロシアニン、チタニルオキシフタロシアニン、銅フタロシアニン、クロルアルミニウムフタロシアニン、クロルインジ ウムフタロシアニン、バナジルオキシフタロシアニン、ジフェノキシゲルマニウムフタロシアニン、クロル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が本発明では好ましく用いられる。
【００７６】
また、フタロシアニン系顔料は結晶多型の化合物として知られ、各種結晶型のフタロシアニン系顔料が見出されている。これらの結晶型や製造方法に関する記述として、無金属フタロシアニンは、特公昭４９−４３３８号公報、特開昭５８−１８２６３９号公報、特開昭６０−１９１５１号公報、特開昭６２−４７０５４号公報、特開昭６２−１４３０５８号公報、特開昭６３−２８６８５７号公報、特開平１−１３８５６３号公報、特開平１−２３０５８１号公報、特開平２−２３３７６９号公報、更にはＪ．Ｐｈｙｓ．Ｃｈｅｍ．７２，３２３０（１９６８）に記載されているものを挙げることができる。
【００７７】
チタニルオキシフタロシアニンは、特開昭６１−２１７０５０号公報、特開昭６２−６７０９４号公報、特開昭６２−２２９２５３号公報、特開昭６３−３６４号公報、特開昭６３−３６５号公報、特開昭６３−３６６号公報、特開昭６３−３７１６３号公報、特開昭６３−８０２６３号公報、特開昭６３−１１６１５８号公報、特開昭６３−１９８０６７号公報、特開昭６３−２１８７６８号公報、特開昭６４−１７０６６号公報、特開平１−１２３８６８号公報、特開平１−１３８５６２号公報、特開平１−１５３７５７号公報、特開平１−１７２４５９号公報、特開平１−１７２４６２号公報、特開平１−１８９２００号公報、特開平１−２０４９６９号公報、特開平１−２０７７５５号公報、特開平１−２９９８７４号公報、特開平２−８２５６号公報、特開平２−９９９６９号公報、特開平２−１３１２４３号公報、特開平２−１６５１５６号公報、特開平２−１６５１５７号公報、特開平２−２１５８６６号公報、特開平２−２６７５６３号公報、特開平２−２９７５６０号公報、特開平３−３５０６４号公報、特開平３−５４２６４号公報、特開平３−８４０６８号公報、特開平３−９４２６４号公報、特開平３−１００６５８号公報、特開平３−１００６５９号公報、特開平３−１２３３５９号公報、特開平３−１９９２６８号公報、特開平３−２００７９０号公報、特開平３−２６９０６４号公報、特開平４−１４５１６６号公報、特開平４−１４５１６７号公報、特開平４−１５３２７３号公報、特開平４−１５９３７３号公報、特開平４−１７９９６４号公報、特開平５−２０２３０９号公報、特開平５−２７９５９２号公報、特開平５−２８９３８０号公報、特開平６−３３６５５４号公報、特開平７−８２５０３号公報、特開平７−８２５０５号公報、更には特開平８−１１０６４９号公報に記載されているものを挙げることができる。
【００７８】
また、銅フタロシアニンは、特公昭５２−１６６７号公報、特開昭５１−１０８８４７号公報、特開昭５５−６０９５８号公報に記載されているものや、更にはγ型、π型、χ型、ρ型などが知られておりこれらを挙げることができる。クロルアルミニウムフタロシアニンは、特開昭５８−１５８６４９号公報、特開昭６２−１３３４６２号公報、特開昭６２−１６３０６０号公報、特開昭６３−４３１５５号公報、更には特開昭６４−７０７６２号公報に、クロルインジウムフタロシアニンは特開昭５９−４４０５４号公報、特開昭６０−５９３５５号公報、特開昭６１−４５２４９号公報、更には特開平７−１３３７５号公報に、バナジルオキシフタロシアニンは、特開昭６３−１８３６１号公報、特開平１−２０４９６８号公報、特開平１−２６８７６３号公報、特開平３−２６９０６３号公報、更には特開平７−２４７４４２号公報に、ジフェノキシゲルマニウムフタロシアニンは、特開平４−３６０１５０号公報に、クロルガリウムフタロシアニンは、特開平５−１９４５２３号公報、更には特開平７−１０２１８３号公報に、ヒドロキシガリウムフタロシアニンは、特開平５−２６３００７号公報、更には特開平７−５３８９２号公報に記載されているものを挙げることができる。
【００７９】
本発明の一般式（１）〜（２）で示される有機光導性化合物を含む感光層を形成するために用いるフィルム形成性結着剤樹脂としては利用分野に応じて種々のものがあげられる 。例えば複写用感光体の用途ではポリスチレン樹脂、ポリビニルアセタール樹脂、ポリスルホン樹脂、ポリカーボネート樹脂、酢ビ・クロトン酸共重合体樹脂、ポリエステル樹脂、ポリフェニレンオキサイド樹脂、ポリアリレート樹脂、アルキッド樹脂、アクリル樹脂、メタクリル樹脂、フェノキシ樹脂あるいはポリ塩化ビニル樹脂などが挙げられる。これらの中でも、ポリスチレン樹脂、ポリビニルアセタール樹脂、ポリカーボネート樹脂、ポリエステル樹脂、ポリアリレート樹脂などは感光体としての電位特性に優れている。また、これらの樹脂は、単独あるいは共重合体のいずれでもよく、またこれらを１種または２種以上を混合して用いることができる。これら結着剤樹脂の光導電性化合物に対して加える量は、２０〜１０００重量％が好ましく、５０〜５００重量％がより好ましい。
【００８０】
積層型感光体の場合、電荷発生層に含有されるこれらの樹脂は、電荷発生物質に対して１０〜５００重量％が好ましく、５０〜１５０重量％がより好ましい。樹脂の比率が高くなりすぎると電荷発生効率が低下し、また樹脂の比率が低くなりすぎると成膜性に問題が生じる。また、電荷輸送層に含有されるこれらの樹脂は、電荷輸送物質に対して２０〜１０００重量％が好ましく、５０〜５００重量％がより好ましい。樹脂の比率が高すぎると感度が低下し、また、樹脂の比率が低くなりすぎると繰り返し特性の悪化や塗膜の欠損を招くおそれがある。
【００８１】
これらの樹脂の中には、引っ張り、曲げ、圧縮などの機械的強度に弱いものがある。この性質を改良するために、可塑性を与える物質を加えることができる。具体的には、フタル酸エステル（例えばＤＯＰ、ＤＢＰなど）、リン酸エステル（例えばＴＣＰ、ＴＯＰなど）、セバシン酸エステル、アジピン酸エステル、ニトリルゴム、塩素化炭化水素などが挙げられる。これらの物質は、必要以上に添加すると電子写真特性の悪影響を及ぼすので、その割合は結着剤樹脂に対し２０重量％以下が好ましい。
【００８２】
その他、感光体中への添加物として酸化防止剤やカール防止剤など、塗工性の改良のためレベリング剤などを必要に応じて添加することができる。
【００８３】
一般式（１）〜（２）で示される化合物は更に他の電荷輸送物質と組み合わせて用いることができる。電荷輸送物質には正孔輸送物質と電子輸送物質がある。前者の例としては、例えば特公昭３４−５４６６号公報などに示されているオキサジアゾール類、特公昭４５−５５５号公報などに示されているトリフェニルメタン類、特公昭５２−４１８８号公報などに示されているピラゾリン類、特公昭５５−４２３８０号公報などに示されているヒドラゾン類、特開昭５６−１２３５４４号公報などに示されているオキサジアゾール類などを挙げることができる。一方、電子輸送物質としては、例えばクロラニル、テトラシアノエチレン、テトラシアノキノジメタン、２，４，７−トリニトロ−９−フルオレノン、２，４，５，７−テトラニトロ−９−フルオレノン、２，４，５，７−テトラニトロキサントン、２，４，８−トリニトロチオキサントン、１，３，７−トリニトロジベンゾチオフェン、１，３，７−トリニトロジベンゾチオフェン−５，５−ジオキシドなどがある。これらの電荷輸送物質は単独または２種以上組み合わせて用いることができる。
【００８４】
また、一般式（１）〜（２）で示される化合物と電荷移動錯体を形成し、更に増感効果を増大させる増感剤として、ある種の電子吸引性化合物を添加することもできる。この電子吸引性化合物としては例えば、２，３−ジクロル−１，４−ナフトキノン、１−ニトロアントラキノン、１−クロル−５−ニトロアントラキノン、２−クロルアントラキノン、フェナントレンキノンなどのキノン類、４−ニトロベンズアルデヒドなどのアルデヒド類、９−ベンゾイルアントラセン、インダンジオン、３，５−ジニトロベンゾフェノン、３，３′，５，５′−テトラニトロベンゾフェノンなどのケトン類、無水フタル酸、４−クロルナフタル酸無水物などの酸無水物、テレフタラルマロノニトリル、９−アントリルメチリデンマロノニトリル、４−ニトロベンザルマロノニトリル、４−（ｐ−ニトロベンゾ イルオキシ）ベンザルマロノニトリルなどのシアノ化合物、３−ベンザルフタリド、３−（α−シアノ−ｐ−ニトロベンザル）フタリド、３−（α−シアノ−ｐ−ニトロベンザル）−４，５，６，７−テトラクロルフタリドなどのフタリド類などを挙げることができる。
【００８５】
本発明の有機光導電性化合物は、感光体の形態に応じて上記の種々の添加物質と共に適当な溶剤中に溶解または分散し、その塗布液を先に述べた導電性支持体上に塗布し、乾燥して感光体を製造することができる。
【００８６】
塗布溶剤としてはクロルホルム、ジクロルエタン、ジクロルメタン、トリクロルエタン、トリクロルエチレン、クロルベンゼン、ジクロルベンゼンなどのハロゲン化炭化水素、ベンゼン、トルエン、キシレンなどの芳香族炭化水素、ジオキサン、テトラヒドロフラン、メチルセロソルブ、エチルセロソルブ、エチレングリコールジメチルエーテルなどのエーテル系溶剤、メチルエチルケトン、メチルイソブチルケトン、メチルイソプロピルケトン、シクロヘキサノンなどのケトン系溶剤、酢酸エチル、ギ酸メチル、メチルセロソルブアセテートなどのエステル系溶剤、Ｎ，Ｎ−ジメチルホルムアミド、アセトニトリル、Ｎ−メチルピロリドン、ジメチルスルホキシドなどの非プロトン性極性溶剤及びｎ−ブタノール、２−プロパノールなどのアルコール系溶剤などを挙げることができる。これらの溶剤は単独または２種以上の混合溶剤として使用することができる。
【００８７】
【実施例】
次に本発明を実施例により更に詳細に説明するが、本発明はこれらに何ら限定されるものではない。
【００８８】
【化９】

【００８９】
【化１０】

【００９０】
【化１１】

【００９１】
合成例１ 例示化合物（ＥＢ−０１）の合成
上記（２１）で示されるアルデヒド化合物５．０ｇ、及び上記（２２）で示されるフォスフォネート化合物１０．６ｇを溶かした１，３−ジオキソラン５０ｍｌ溶液に、室温で撹拌下、カリウムｔ−ブトキシド２．７ｇをゆっくりと加えた。室温下３０分撹拌を続けた後、反応液を氷水４００ｍｌと酢酸エチル１００ｍｌの混合液に注ぎ込んで反応を停止し、３０分撹拌した後有機層を分液し、更に水層を酢酸エチル１００ｍｌで２回抽出した。有機層をまとめ、飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥し、減圧下溶媒を留去した。得られたオイル状物質をシリカゲルカラムクロマトグラフィー（溶出溶媒：ヘキサン／酢酸エチル＝７／１）で精製して目的とする化合物（ＥＢ−０１）２．４８ｇを得た。
【００９２】
参考例１
アゾ顔料（Ｋ−１）１重量部及びポリエステル樹脂（東洋紡製バイロン２００）１重量部をテトラヒドロフラン１００重量部と混合し、ペイントコンディショナー装置でガラスビーズと共に２時間分散した。こうして得た分散液を、アプリケーターにてアルミ蒸着ポリエステル上に塗布して乾燥し、膜厚約０．２μｍの電荷発生層を形成した。次に例示化合物（ＥＢ−０１）を、ポリアリレート樹脂（ユニチカ製Ｕ−ポリマー）と１：１の重量比で混合し、ジクロルエタンを溶媒として１０重量％の溶液を作り、上記の電荷発生層の上にアプリケーターで塗布して膜厚約２０μｍの電荷輸送層を形成した。
【００９３】
この様にして作製した積層型感光体について、静電記録試験装置（川口電機製ＳＰ−４２８）を用いて電子写真特性の評価を行なった。
測定条件：印加電圧−６ｋＶ、スタティック No. ３（ターンテーブルの回転スピードモード：１０ｍ／ｍｉｎ ）。その結果、帯電電位（Ｖ ₀ ）が−７５０Ｖ半減露光量（Ｅ 1/2 ）が１．２ルックス・秒と高感度の値を示した。
【００９４】
更に同装置を用いて、帯電−除電（除電光：白色光で４００ルックス×１秒照射）を１サイクルとする繰返し使用に対する特性評価を行った。５０００回での繰返しによる帯電電位の変化を求めたところ、１回目の帯電電位（Ｖ ₀ ）−７５０Ｖに対し、５０００回目の帯電電位（Ｖ ₀ ）は−７４０Ｖであり、繰返しによる電位の低下がほとんどなく安定した特性を示した。また、１回目の半減露光量（Ｅ 1/2 ）１．２ルックス・秒に対して５０００回目の半減露光量（Ｅ 1/2 ）は１．２ルックス・秒と変化がなく優れた特性を示した。
【００９５】
実施例１〜１０
参考例１のアゾ顔料（Ｋ−１）及び例示化合物（ＥＢ−０１）の代わりに、それぞれ表４６に示すアゾ顔料、及び本発明の化合物を用いた他は、参考例１と同様にして感光体を作製してその特性を評価した。結果を表４６に示す。
【００９６】
【表４６】

【００９７】
参考例２
アゾ顔料（Ｊ−２）１重量部とテトラヒドロフラン４０重量部を、ペイントコンディショナー装置でガラスビーズと共に８時間分散処理した。こうして得た分散液に、例示化合物（ＥＪ−０３）を２．５重量部、ポリカーボネート樹脂（三菱瓦斯化学製ＰＣＺ−２００）１０重量部、テトラヒドロフラン６０重量部を加え、更にペイントコンディショナー装置で３０分間分散処理を行った後、アプリケーターにてアルミ蒸着ポリエステル上に塗布し、膜厚約１５μｍの感光層を形成した。この感光体の電子写真特性を、参考例１と同様にして評価した。ただし、印加電圧のみ＋５ｋＶに変更した。その結果、１回目の帯電電位（Ｖ ₀ ）＋４６０Ｖ、半減露光量（Ｅ 1/2 ）１．４ルックス・秒、５０００回繰り返し後の帯 電電位（Ｖ ₀ ）＋４５０Ｖ、半減露光量（Ｅ 1/2 ）１．４ルックス・秒と、高感度でしかも変化の少ない、優れた特性を示した。
【００９８】
【化１２】

【００９９】
実施例１１〜２０
参考例２のアゾ顔料（Ｊ−２）及び例示化合物（ＥＪ−０３）の代わりに、それぞれ表４７に示すアゾ顔料及び本発明の化合物を用いた他は、参考例２と同様にして感光体を作製してその特性を評価した。結果を表４７に示す。
【０１００】
【表４７】

【０１０１】
実施例２１〜２５
参考例１のアゾ顔料（Ｋ−１）の代わりにＣｕＫα１．５４１オングストロームのＸ 線に対するブラッグ角（２θ±０．２°）が、９．５°、９．７°、１１．７°、１５．０°、２３．５°、２４．１°、２７．３°に主要なピークを示すＸ線回折スペクトルを有するチタニルオキシフタロシアニン（Ｙ型チタニルオキシフタロシアニン）を、例示化合物（ＥＢ−０１）の代わりにそれぞれ表４８に示す本発明の化合物を用いた他は、参考例１と同様にして感光体を作製してその特性を評価した。結果を表４８に示す。
【０１０２】
【表４８】

【０１０３】
実施例２６〜３０
参考例２のアゾ顔料（Ｊ−２）の代わりにＹ型チタニルオキシフタロシアニンを、例示化合物（ＥＪ−０３）の代わりにそれぞれ表４９に示す本発明の化合物を用いた他は、参考例２と同様にして感光体を作製してその特性を評価した。結果を表４９に示す。
【０１０４】
【表４９】

【０１０５】
比較例１
電荷輸送物質として例示化合物（ＥＢ−０１）の代わりに下記に示す比較化合物（ＲＡ−１）を用いた他は、参考例１と同様の操作で感光体を作製し特性を評価した結果、１回目の帯電電位（Ｖ ₀ ）−６４０Ｖに対し、５０００回目の帯電電位（Ｖ ₀ ）は−３４０Ｖであり、初期の帯電電位が悪い上に、繰返しによる大幅な電位の低下がみられた。また、１回目の半減露光量（Ｅ 1/2 ）２．３ルックス・秒に対して５０００回目の半減露光量（Ｅ 1/2 ）は５．５ルックス・秒と感度の低下もみられた。
【０１０６】
【化１３】

【０１０７】
比較例２〜１０
同様にして、電荷輸送物質として例示化合物（ＥＢ−０１）の代わりに下記に示す比較化合物（ＲＢ−１〜ＲＫ−１）を用いた他は、参考例１と同様の操作で感光体を作製し特性を評価した。結果は表５０に示したように、全てのもので感度の低下や、繰り返しによる帯電電位の低下がみられた。
【０１０８】
【化１４】

【０１０９】
【化１５】

【０１１０】
【化１６】

【０１１１】
【化１７】

【０１１２】
【化１８】

【０１１３】
【化１９】

【０１１４】
【化２０】

【０１１５】
【化２１】

【０１１６】
【化２２】

【０１１７】
【表５０】

【０１１８】
【発明の効果】
以上から明らかなように、本発明の有機光導電性化合物を用いれば高感度で高耐久性を有する、優れた電子写真感光体を提供することができる。 [0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an organic photoconductive compound and an electrophotographic photosensitive member using the same.
[0002]
[Prior art]
  In recent years, the use of electrophotography is not limited to the field of copying machines, but has spread to fields where photographic technology has been used in the past, such as printing plate materials, slide films, and microfilms, and lasers, LEDs, and CRTs are used as light sources. Applications to high-speed printers are also being considered. Recently, application of photoconductive materials to applications other than electrophotographic photoreceptors, such as electrostatic recording elements, sensor materials, EL elements, etc., has begun to be studied. Accordingly, the demand for photoconductive materials and electrophotographic photoreceptors using the same is becoming high and wide. To date, inorganic photoconductive substances such as selenium, cadmium sulfide, zinc oxide, and silicon are known as electrophotographic photoreceptors, and have been widely studied and put into practical use. These inorganic materials have many advantages and at the same time have various drawbacks. For example, selenium has the disadvantages that the production conditions are difficult and that it is easily crystallized by heat or mechanical impact, and cadmium sulfide and zinc oxide have difficulty in moisture resistance and durability. Silicon has been pointed out to be insufficiently charged and difficult to manufacture. Furthermore, selenium and cadmium sulfide also have toxicity issues.
[0003]
  In contrast, organic photoconductive materials have good film-forming properties, excellent flexibility, light weight, good transparency, and design of photoreceptors over a wide range of wavelengths by appropriate sensitization methods. Therefore, its practical application is gradually attracting attention.
[0004]
  By the way, a photoreceptor used in electrophotographic technology generally requires the following as a basic property. That is, (1) high chargeability with respect to corona discharge in a dark place, (2) little leakage (dark decay) of the obtained charged charge in the dark place, and (3) charged charge due to light irradiation. (4) There is little residual charge after light irradiation, and the like.
[0005]
  However, to date, many studies have been made on photoconductive polymers such as polyvinyl carbazole as organic photoconductive substances. However, these films do not always have sufficient film properties, flexibility, and adhesive properties. It is difficult to say that it has sufficient basic properties as a photoreceptor.
[0006]
  On the other hand, for organic low-molecular photoconductive compounds, a photoconductor excellent in mechanical strength such as film property, adhesiveness, and flexibility can be obtained by selecting a binder used for forming the photoconductor. However, it is difficult to find a compound suitable for maintaining high sensitivity characteristics.
[0007]
  In order to improve such points, organic photoreceptors having higher sensitivity characteristics have been developed by sharing the charge generation function and the charge transport function with different substances. The feature of such photoconductors, which are called function-separated types, is that a material suitable for each function can be selected from a wide range, and a photoconductor having an arbitrary performance can be easily produced. Has been promoted.
[0008]
  Among these, various substances such as phthalocyanine pigments, squalium dyes, azo pigments and perylene pigments have been studied as substances responsible for the charge generation function. Among them, azo pigments can have various molecular structures, and are also high. It has been widely researched because of its expectation of charge generation efficiency, and its practical application is also progressing. However, in this azo pigment, the relationship between the molecular structure and the charge generation efficiency is still unclear. The reality is that we are exploring optimal structures by accumulating vast amounts of synthetic research, but sufficiently satisfy the basic properties and high durability requirements for the photoreceptors listed above. Things have not been obtained yet.
[0009]
  On the other hand, there are a hole transport material and an electron transport material as the materials responsible for the charge transport function. Various substances such as hydrazone compounds and stilbene compounds as hole transport materials and 2,4,7-trinitro-9-fluorenone and diphenoquinone derivatives as electron transport materials have been studied and put into practical use. The fact is that we are searching for the optimal structure by accumulating a huge amount of synthetic research. In fact, many improvements have been made so far, but a product that sufficiently satisfies the basic properties and high durability required for the photosensitive member described above has not been obtained.
[0010]
  As described above, various improvements have been made in the production of electrophotographic photosensitive members, but they sufficiently satisfy the basic properties and high durability required for the photosensitive members listed above. Is not yet available.
[0011]
[Problems to be solved by the invention]
  The object of the present invention is to be used for an electrophotographic photosensitive member and a sensor material, an EL element, an electrostatic recording element, etc. that have a high charging potential, a high sensitivity, and can exhibit stable performance without changing various characteristics even when used repeatedly. It is to provide a possible organic photoconductive compound.
[0012]
[Means for Solving the Problems]
  As a result of researches on photoconductive compounds to achieve the above object, the present inventors have found that an organic photoconductive compound having a specific structure is effective, and have reached the present invention. Examples of the organic photoconductive compound having a specific structure described above include bis-stilbene compounds represented by the following general formula (1). Among them, the bisstilbene compound represented by the following general formula (2) is preferable in the present invention. Examples include stilbene compounds.
[0013]
[Chemical 3]

[0014]
[Formula 4]

[0015]
  In the general formula (1) or (2), X represents an oxygen atom or a sulfur atom, and R ₁ And R ₂ Represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, or a halogen atom, and R _Three Represents a hydrogen atom, an alkyl group optionally having a substituent, an aralkyl group, an aryl group, or a heterocyclic ring. Ar ₁ Represents an aryl group which may have a substituent, or a heterocyclic ring.
[0016]
  Here, specific examples of X include an oxygen atom or a sulfur atom.
[0017]
  R ₁ , R ₂ Specific examples of these include hydrogen atoms, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups and other lower alkyl groups, methoxy groups, ethoxy groups, n-propoxy groups, n-butoxy groups, and the like. A lower alkoxy group or a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom can be exemplified.
[0018]
  R _Three Specific examples of methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, 3-methoxypropyl group, 2-chloro- Unsubstituted or substituted alkyl group such as 3-methylhexyl group, benzyl group, phenethyl group, 3-phenylpropyl group, p-methylbenzyl group, o-methoxybenzyl group, 3,5-dichlorobenzyl group, 2,4 -Unsubstituted or substituted aralkyl groups such as dimethylphenethyl group, p-methoxyphenethyl group, 2-methyl-3-phenylpropyl group, phenyl group, p-tolyl group, m-tolyl group, p-methoxyphenyl group, o- Methoxyphenyl group, p-chlorophenyl group, 3,5-dimethylphenyl group, 4-methoxy-2-chlorophenyl group, 3,5-dimethone Unsubstituted or substituted aryl group such as siphenyl group, 1-naphthyl group, 1-methyl-2-naphthyl group, 9-phenanthryl group, 1-pyrenyl group, 2-furyl group, 2-thienyl group, 2-pyridyl group , Unsubstituted or substituted heterocyclic groups such as 2,6-dimethyl-4-pyridyl group, 3-indolyl group, 2-quinolyl group, etc. Can be mentioned.
[0019]
  Ar ₁ Specific examples of these include phenyl group, p-tolyl group, m-tolyl group, p-methoxyphenyl group, o-methoxyphenyl group, p-chlorophenyl group, 3,5-dimethylphenyl group, 4-methoxy-2. -Unsubstituted or substituted aryl group such as chlorophenyl group, 3,5-dimethoxyphenyl group, 1-naphthyl group, 1-methyl-2-naphthyl group, 9-phenanthryl group, 1-pyrenyl group, 2-furyl group, Examples thereof include unsubstituted or substituted heterocyclic groups such as 2-thienyl group, 2-pyridyl group, 2,6-dimethyl-4-pyridyl group, 3-indolyl group, and 2-quinolyl group.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
  Specific examples of the organic photoconductive compound represented by the general formula (1) or (2) according to the present invention include the bis-stilbene compounds of EA-01 to 20 shown below. It is not limited.
[0021]
[Chemical formula 5]

[0022]
[Chemical 6]

[0023]
[Chemical 7]

[0024]
[Chemical 8]

[0025]
  Any of the forms of the electrophotographic photoreceptor including the photosensitive layer containing the organic photoconductive compound represented by the general formulas (1) to (2) of the present invention can be used. For example, there is one in which a photosensitive layer made of a charge generating substance, a charge transporting substance, and a film-forming binder resin is provided on a conductive support. There is also known a laminated type photoreceptor in which a charge generation layer made of a charge generation material and a binder resin and a charge transport layer made of a charge transport material and a binder resin are provided on a conductive support. . Either the charge generation layer or the charge transport layer may be an upper layer. If necessary, an undercoat layer is provided between the conductive support and the photosensitive layer, an overcoat layer is provided on the surface of the photosensitive member, and in the case of a laminated type photosensitive member, an intermediate layer is provided between the charge generation layer and the charge transporting layer. Can also be provided. As a support for producing a photoreceptor using the compound of the present invention, a metal drum, a metal plate, a sheet of paper or plastic film subjected to conductive processing, a drum-like or belt-like support, and the like are used. The
[0026]
  The electrophotographic photoreceptor of the present invention can be obtained by containing one or more of the organic photoconductive compounds represented by the general formulas (1) to (2) and a charge generating substance. The charge generation material includes an inorganic charge generation material and an organic charge generation material. Examples of the former include selenium, selenium-tellurium alloy, selenium-arsenic alloy, cadmium sulfide, zinc oxide, and amorphous silicon. Examples of organic charge generating materials include triphenylmethane dyes such as methyl violet, brilliant green and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, cyanine dyes, acridine dyes, pyrylium dyes, thiapyrylium dyes , Squalium dyes, perinone pigments, anthraquinone pigments, perylene pigments, metal-containing or metal-free phthalocyanes Examples thereof include nin pigments, and azo pigments are also used.
[0027]
  Examples of the azo pigment include JP-A-47-37543, JP-A-53-95033, JP-A-53-132347, JP-A-53-133445, and JP-A-54-12742. JP-A-54-20736, JP-A-54-20737, JP-A-54-21728, JP-A-54-22834, JP-A-55-69148, JP-A-55. JP-A-69654, JP-A-55-79449, JP-A-55-117151, JP-A-56-46237, JP-A-56-1116039, JP-A-56-11640, JP-A-56-119134, JP-A-56-143437, JP-A-57-63537, JP-A-57-63538, JP-A-57-63541 JP-A-57-63542, JP-A-57-63549, JP-A-57-66438, JP-A-57-74746, JP-A-57-78542, JP-A-57- 78543, JP-A-57-90056, JP-A-57-90057, JP-A-57-90632, JP-A-57-116345, JP-A-57-202349, Japanese Laid-Open Patent Publication Nos. 58-4151, 58-90644, 58-144358, 58-177955, 59-19662, 59-33253 JP, 59-71059, 59-72448, 59-78356, 59-136351, 59-201060. JP, 60-15642, JP 60-14351, JP 60-179746, JP 61-11754, JP 61-90164, JP JP 61-90165, JP 61-90166, JP 61-112154, JP 61-269165, 61-281245, 61-51063 JP, 62-267363, JP 63-68844, JP 63-89866, JP 63-139355, JP 63-142033, JP 63 -183450, JP-A 63-282743, JP-A 64-21455, JP-A 64-78259, JP-A 1-200267, JP-A 1-2 No. 02757, JP-A-1-319754, JP-A-2-72372, JP-A-2-254467, JP-A-3-95561, JP-A-3-27863, JP-A-4-96068. JP-A-4-96069, JP-A-4-147265, JP-A-5-142841, JP-A-5-303226, JP-A-6-324504, JP-A-7-168379, etc. And the compounds described in the above.
[0028]
  Moreover, the structure of the coupler component used in these azo pigments varies widely. For example, JP-A-54-17735, JP-A-54-79632, JP-A-57-176055, JP-A-59-97043, JP-A-60-130746, JP-A-60- -153050, JP-A-60-103048, JP-A-60-189759, JP-A-63-131146, JP-A-63-155052, JP-A-2-11069, Examples thereof include compounds described in Kaihei 4-149448, JP-A-6-27705, JP-A-6-348047, and the like.
[0029]
  Specific examples of the azo pigment include compounds shown in Tables 1 to 45 below, but are not limited thereto. It is also possible to use these compounds in combination with other charge generation materials.
[0030]
[Table 1]

[0031]
[Table 2]

[0032]
[Table 3]

[0033]
[Table 4]

[0034]
[Table 5]

[0035]
[Table 6]

[0036]
[Table 7]

[0037]
[Table 8]

[0038]
[Table 9]

[0039]
[Table 10]

[0040]
[Table 11]

[0041]
[Table 12]

[0042]
[Table 13]

[0043]
[Table 14]

[0044]
[Table 15]

[0045]
[Table 16]

[0046]
[Table 17]

[0047]
[Table 18]

[0048]
[Table 19]

[0049]
[Table 20]

[0050]
[Table 21]

[0051]
[Table 22]

[0052]
[Table 23]

[0053]
[Table 24]

[0054]
[Table 25]

[0055]
[Table 26]

[0056]
[Table 27]

[0057]
[Table 28]

[0058]
[Table 29]

[0059]
[Table 30]

[0060]
[Table 31]

[0061]
[Table 32]

[0062]
[Table 33]

[0063]
[Table 34]

[0064]
[Table 35]

[0065]
[Table 36]

[0066]
[Table 37]

[0067]
[Table 38]

[0068]
[Table 39]

[0069]
[Table 40]

[0070]
[Table 41]

[0071]
[Table 42]

[0072]
[Table 43]

[0073]
[Table 44]

[0074]
[Table 45]

[0075]
  As the phthalocyanine pigment used in the present invention, any of phthalocyanines known per se and derivatives thereof can be used. Specifically, metal-free phthalocyanines, titanyloxyphthalocyanines, copper phthalocyanines, aluminum phthalocyanines, diphenoxy Germanium phthalocyanines, germanium phthalocyanines, gallium phthalocyanines, chlorogallium phthalocyanines, bromogallium phthalocyanines, chloroindium phthalocyanines, bromoindium phthalocyanines, iodoindium phthalocyanines, magnesium phthalocyanines, chloraluminum phthalocyanines, bromoaluminum phthalocyanines , Tin phthalocyanines, dichlorotin phthalocyanines, vanadyloxy Tarocyanines, zinc phthalocyanines, cobalt phthalocyanines, nickel phthalocyanines, hydroxygallium phthalocyanines, dihydroxygallium phthalocyanines, barium phthalocyanines, beryllium phthalocyanines, cadmium phthalocyanines, chlorocobalt phthalocyanines, dichlorotitanyl phthalocyanines, iron phthalocyanines , Silicon phthalocyanines, lead phthalocyanines, platinum phthalocyanines, metal-free naphthalocyanines, aluminum naphthalocyanines, titanyloxynaphthalocyanines, ruthenium phthalocyanines, palladium phthalocyanines and the like. In particular, metal-free phthalocyanine, titanyloxyphthalocyanine, copper phthalocyanine, chloraluminum phthalocyanine, chlorindylene Umphthalocyanine, vanadyloxyphthalocyanine, diphenoxygermanium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine are preferably used in the present invention.
[0076]
  Moreover, phthalocyanine pigments are known as crystalline polymorphic compounds, and various crystalline phthalocyanine pigments have been found. As a description of these crystal types and production methods, metal-free phthalocyanines are disclosed in JP-B-49-4338, JP-A-58-182639, JP-A-60-19151, and JP-A-62-47054. JP-A-62-143058, JP-A-63-286857, JP-A-1-138563, JP-A-1-230581, JP-A-2-233769, and J. Org. Phys. Chem. 72, 3230 (1968).
[0077]
  Titanyloxyphthalocyanine is disclosed in JP-A-61-217050, JP-A-62-267094, JP-A-62-229253, JP-A-63-364, JP-A-63-365, JP-A 63-366, JP-A 63-37163, JP-A 63-80263, JP-A 63-116158, JP-A 63-198067, JP-A 63- No. 218768, JP-A 64-17066, JP-A 1-123868, JP-A 1-1138562, JP-A 1-153757, JP-A 1-172459, JP-A 1-172462. No. 1, JP-A-1-189200, JP-A-1-204969, JP-A-1-207755, JP-A-1-299874, -8256, JP-A-2-99969, JP-A-2-131243, JP-A-2-165156, JP-A-2-165157, JP-A-2-215866, JP-A-2-267563. No. 2, JP-A-2-297560, JP-A-3-35064, JP-A-3-54264, JP-A-3-84068, JP-A-3-94264, JP-A-3-100168. JP-A-3-100699, JP-A-3-123359, JP-A-3-199268, JP-A-3-200790, JP-A-3-269064, JP-A-4-145166, No. 4-145167, JP-A-4-153273, JP-A-4-159373, JP-A-4-179964 JP-A-5-202309, JP-A-5-279592, JP-A-5-289380, JP-A-6-336554, JP-A-7-82503, JP-A-7-82505, Include those described in JP-A-8-110649.
[0078]
  Further, copper phthalocyanine includes those described in JP-B-52-1667, JP-A-51-108847, JP-A-55-60958, and γ-type, π-type, χ-type, ρ type and the like are known and can be mentioned. Chloraluminum phthalocyanine is disclosed in JP-A-58-158649, JP-A-62-133462, JP-A-62-163060, JP-A-63-43155, and further JP-A-64-70762. Chlorindium phthalocyanine is disclosed in JP-A-59-44054, JP-A-60-59355, JP-A-61-45249, and further JP-A-7-13375. In JP-A-63-18361, JP-A-1-204968, JP-A-1-268863, JP-A-3-269663, and further in JP-A-7-247442, diphenoxygermanium phthalocyanine is JP-A-4-360150 discloses chlorogallium phthalocyanine as JP-A-5-1. 4523 JP, even in JP-A-7-102183, hydroxygallium phthalocyanine, JP-A-5-263007, JP-even can be exemplified those described in JP-A-7-53892.
[0079]
  The film-forming binder resin used for forming the photosensitive layer containing the organic photoconductive compound represented by the general formulas (1) to (2) of the present invention includes various types depending on the application field. . For example, in the use of photoconductors for copying, polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, vinyl acetate / crotonic acid copolymer resin, polyester resin, polyphenylene oxide resin, polyarylate resin, alkyd resin, acrylic resin, methacrylic resin Phenoxy resin or polyvinyl chloride resin. Among these, polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polyester resin, polyarylate resin, and the like are excellent in potential characteristics as a photoreceptor. These resins may be either single or copolymer, and these may be used alone or in combination of two or more. The amount of the binder resin added to the photoconductive compound is preferably 20 to 1000% by weight, and more preferably 50 to 500% by weight.
[0080]
  In the case of a multilayer photoreceptor, these resins contained in the charge generation layer are preferably 10 to 500% by weight, more preferably 50 to 150% by weight, based on the charge generation material. If the resin ratio is too high, the charge generation efficiency decreases, and if the resin ratio is too low, there is a problem in film formability. In addition, these resins contained in the charge transport layer are preferably 20 to 1000% by weight, more preferably 50 to 500% by weight with respect to the charge transport material. If the ratio of the resin is too high, the sensitivity is lowered, and if the ratio of the resin is too low, the repeated characteristics may be deteriorated or the coating film may be lost.
[0081]
  Some of these resins are weak in mechanical strength such as pulling, bending, and compression. To improve this property, a plasticizing substance can be added. Specific examples include phthalic acid esters (for example, DOP and DBP), phosphoric acid esters (for example, TCP and TOP), sebacic acid esters, adipic acid esters, nitrile rubber, and chlorinated hydrocarbons. When these substances are added more than necessary, the electrophotographic characteristics are adversely affected, and therefore the ratio is preferably 20% by weight or less based on the binder resin.
[0082]
  In addition, a leveling agent or the like can be added as necessary to improve the coatability, such as an antioxidant or an anti-curl agent, as additives in the photoreceptor.
[0083]
  The compounds represented by the general formulas (1) to (2) can be used in combination with other charge transport materials. Charge transport materials include hole transport materials and electron transport materials. Examples of the former include, for example, oxadiazoles shown in Japanese Patent Publication No. 34-5466, triphenylmethanes shown in Japanese Patent Publication No. 45-555, and Japanese Patent Publication No. 52-4188. And the like, hydrazones shown in JP-B-55-42380, oxadiazoles shown in JP-A-56-123544, and the like. On the other hand, examples of the electron transport material include chloranil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 1,3,7-trinitrodibenzothiophene, 1,3,7-trinitrodibenzothiophene-5,5-dioxide. These charge transport materials can be used alone or in combination of two or more.
[0084]
  Further, as a sensitizer that forms a charge transfer complex with the compounds represented by the general formulas (1) to (2) and further increases the sensitizing effect, a certain kind of electron withdrawing compound can be added. Examples of the electron withdrawing compound include 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, quinones such as phenanthrenequinone, 4-nitro Aldehydes such as benzaldehyde, ketones such as 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 3,3 ', 5,5'-tetranitrobenzophenone, phthalic anhydride, 4-chloronaphthalic anhydride, etc. Acid anhydride, terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalononitrile, 4- (p-nitrobenzo) Yloxy) cyano compounds such as benzalmalononitrile, 3-benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,5,6,7-tetrachloro Examples thereof include phthalides such as phthalide.
[0085]
  The organic photoconductive compound of the present invention is dissolved or dispersed in an appropriate solvent together with the above-mentioned various additives depending on the form of the photoreceptor, and the coating solution is applied onto the conductive support described above. The photosensitive member can be manufactured by drying.
[0086]
  Coating solvents include chloroform, dichloroethane, dichloromethane, trichloroethane, trichloroethylene, chlorobenzene, dichlorobenzene and other aromatic hydrocarbons, benzene, toluene, xylene and other aromatic hydrocarbons, dioxane, tetrahydrofuran, methyl cellosolve and ethyl cellosolve. , Ether solvents such as ethylene glycol dimethyl ether, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, cyclohexanone, ester solvents such as ethyl acetate, methyl formate, methyl cellosolve acetate, N, N-dimethylformamide, acetonitrile Aprotic polar solvents such as N-methylpyrrolidone and dimethyl sulfoxide, and n-butanol and 2-propanol Or the like can be mentioned alcohol-based solvent. These solvents can be used alone or as a mixed solvent of two or more.
[0087]
【Example】
  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to these at all.
[0088]
[Chemical 9]

[0089]
[Chemical Formula 10]

[0090]
Embedded image

[0091]
  Synthesis Example 1 Synthesis of Exemplary Compound (EB-01)
  To a solution of 5.0 g of the aldehyde compound represented by the above (21) and 10.6 g of the phosphonate compound represented by the above (22) in 50 ml of 1,3-dioxolane, potassium t-butoxide 2 was stirred at room temperature. .7 g was added slowly. After stirring at room temperature for 30 minutes, the reaction solution was poured into a mixed solution of 400 ml of ice water and 100 ml of ethyl acetate to stop the reaction. After stirring for 30 minutes, the organic layer was separated, and the aqueous layer was further washed with 100 ml of ethyl acetate. Extracted twice. The organic layers were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The obtained oily substance was purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 7/1) to obtain 2.48 g of the desired compound (EB-01).
[0092]
  Reference example 1
  1 part by weight of an azo pigment (K-1) and 1 part by weight of a polyester resin (Toyobo Byron 200) were mixed with 100 parts by weight of tetrahydrofuran, and dispersed with glass beads in a paint conditioner device for 2 hours. The dispersion thus obtained was applied onto an aluminum vapor-deposited polyester with an applicator and dried to form a charge generation layer having a thickness of about 0.2 μm. Next, exemplary compound (EB-01) was mixed with polyarylate resin (U-polymer manufactured by Unitika) at a weight ratio of 1: 1 to make a 10% by weight solution using dichloroethane as a solvent. A charge transport layer having a film thickness of about 20 μm was formed by coating with an applicator.
[0093]
  The laminated photoconductors thus produced were evaluated for electrophotographic characteristics using an electrostatic recording test apparatus (SP-428 manufactured by Kawaguchi Electric).
  Measurement conditions: applied voltage -6 kV, static No. 3 (Turntable rotation speed mode: 10m / min ). As a result, the charging potential (V ₀ ) Is -750V half exposure (E 1/2 ) Showed a high sensitivity value of 1.2 lux.sec.
[0094]
  Furthermore, using the same apparatus, the characteristics were evaluated for repeated use in which charging-static elimination (static elimination light: 400 lux × 1 second irradiation with white light) was taken as one cycle. When the change in the charging potential due to repetition at 5000 times was determined, the first charging potential (V ₀ ) -750V vs. 5000th charging potential (V ₀ ) Was −740 V, and showed stable characteristics with almost no decrease in potential due to repetition. In addition, the first half exposure (E 1/2 ) The half-exposure dose at the 5000th time for 1.2 lux.sec (E 1/2 ) Showed excellent characteristics with no change of 1.2 lux · sec.
[0095]
  Examples 1-10
  Photosensitization was performed in the same manner as in Reference Example 1 except that the azo pigment shown in Table 46 and the compound of the present invention were used in place of the azo pigment (K-1) and exemplary compound (EB-01) of Reference Example 1, respectively. A body was prepared and its characteristics were evaluated. The results are shown in Table 46.
[0096]
[Table 46]

[0097]
  Reference example 2
  One part by weight of the azo pigment (J-2) and 40 parts by weight of tetrahydrofuran were dispersed with a glass bead for 8 hours using a paint conditioner device. 2.5 parts by weight of the exemplified compound (EJ-03), 10 parts by weight of a polycarbonate resin (PCZ-200 manufactured by Mitsubishi Gas Chemical), and 60 parts by weight of tetrahydrofuran are added to the dispersion thus obtained, and further for 30 minutes using a paint conditioner device. After carrying out the dispersion treatment, it was coated on aluminum vapor-deposited polyester with an applicator to form a photosensitive layer having a thickness of about 15 μm. The electrophotographic characteristics of this photoreceptor were evaluated in the same manner as in Reference Example 1. However, only the applied voltage was changed to +5 kV. As a result, the first charging potential (V ₀ ) + 460V, half exposure (E 1/2 ) 1.4 lux / second, after 5,000 repetitions Electric potential (V ₀ ) + 450V, half exposure (E 1/2 ) 1.4 lux.sec. Excellent characteristics with high sensitivity and little change.
[0098]
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[0099]
  Examples 11-20
  A photoconductor in the same manner as in Reference Example 2, except that the azo pigment shown in Table 47 and the compound of the present invention were used instead of the azo pigment (J-2) and the exemplary compound (EJ-03) of Reference Example 2, respectively. Were fabricated and their characteristics were evaluated. The results are shown in Table 47.
[0100]
[Table 47]

[0101]
  Examples 21-25
  Instead of the azo pigment (K-1) in Reference Example 1, CuKα1.541 angstrom X Bragg angles (2θ ± 0.2 °) with respect to the line are mainly 9.5 °, 9.7 °, 11.7 °, 15.0 °, 23.5 °, 24.1 °, 27.3 ° Reference Example 1 except that titanyloxyphthalocyanine (Y-type titanyloxyphthalocyanine) having an X-ray diffraction spectrum exhibiting a unique peak was used instead of the exemplified compound (EB-01) in accordance with the compound of the present invention shown in Table 48. A photoreceptor was prepared in the same manner as described above and its characteristics were evaluated. The results are shown in Table 48.
[0102]
[Table 48]

[0103]
  Examples 26-30
Reference Example 2 was used except that Y-type titanyloxyphthalocyanine was used instead of the azo pigment (J-2) of Reference Example 2 and the compound of the present invention shown in Table 49 was used instead of the exemplified compound (EJ-03). Similarly, a photoconductor was prepared and its characteristics were evaluated. The results are shown in Table 49.
[0104]
[Table 49]

[0105]
  Comparative Example 1
  As a result of producing a photoconductor and evaluating the characteristics by the same operation as in Reference Example 1 except that the following compound (RA-1) shown below was used instead of the exemplified compound (EB-01) as a charge transport material, Second charging potential (V ₀ ) -640V vs. 5000th charging potential (V ₀ ) Was −340V, and the initial charging potential was poor, and a significant decrease in potential due to repetition was observed. In addition, the first half exposure (E 1/2 ) The half-exposure amount at the 5000th time for 2.3 lux.sec (E 1/2 ) Showed a decrease in sensitivity of 5.5 lux · sec.
[0106]
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[0107]
  Comparative Examples 2-10
  Similarly, a photoconductor was prepared in the same manner as in Reference Example 1 except that the following comparative compounds (RB-1 to RK-1) were used as the charge transport material instead of the exemplary compound (EB-01). The characteristics were evaluated. As shown in Table 50, the results showed a decrease in sensitivity and a decrease in charging potential due to repetition.
[0108]
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[0109]
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[0110]
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[0111]
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[0112]
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[0113]
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[0114]
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[0115]
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[0116]
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[0117]
[Table 50]

[0118]
【The invention's effect】
  As is clear from the above, an excellent electrophotographic photosensitive member having high sensitivity and high durability can be provided by using the organic photoconductive compound of the present invention.

Claims (4)

An organic photoconductive compound represented by the following general formula (1).

(In General Formula (1), X represents an oxygen atom or a sulfur atom, R ₁ and R ₂ represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, or a halogen atom, and R ₃ represents a hydrogen atom or a substituent. An alkyl group, an aralkyl group, an aryl group, or a heterocyclic ring that may have a substituent, and Ar ₁ represents an aryl group or a heterocyclic ring that may have a substituent. The organic photoconductive compound of Claim 1 shown by following General formula (2).

(In general formula (2), X and Ar ₁ are the same as in general formula (1).) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one organic photoconductive compound represented by the general formulas (1) to (2) on a conductive support. The photosensitive layer contains a charge generation material and a charge transport material, and the charge transport material is at least one of the organic photoconductive compounds represented by the general formulas (1) to (2). Item 4. The electrophotographic photosensitive member according to Item 3.