JP3981461B2 - Electrophotographic photoreceptor - Google Patents

Description

【００１２】
〔一般式（１）中、ベンゼン環Ａ、Ｂ、ＣおよびＤはそれぞれ置換基としてアルキル基またはアリール基を有していてもよく、Ｙは置換基を有していてもよいアルキレン基を表す。
一般式（２）および（３）において、Ｚは下記一般式（２−ａ）または（２−ｂ）で表されるテトラゾ成分残基を表し、
【００１３】
【化１１】

【００１４】
一般式（２−ａ）、（２−ｂ）中、Ｒ^１ 、Ｒ^２ 、Ｒ^３ およびＲ^４ は水素原子、ハロゲン原子、アルキル基またはアルコキシ基を表し、これらは互いに同一でも異なっていてもよく、Ｇはベンゼン環と共に縮合環を形成する残基を表し、Ｊはヘテロ原子、２価の炭化水素基、ヘテロ環または２価の炭化水素基とヘテロ環が連結した基を表す。但し、下記一般式（ｊ）で表される基を除く。
【００１５】
【化１２】

【００１６】
（式中、Ｒは水素原子または置換或いは未置換のアルキル基或いは複素環基であり、ｎは０または１である。）
Ｃｐ_１ 、Ｃｐ_２ 、Ｃｐ_３ 、Ｃｐ_４ およびＣｐ_５ はそれぞれカップラー残基を表
す。但しＣｐ_１ およびＣｐ_２ が下記一般式（４）で表される基である場合を除く
。
【００１７】
【化１３】

【００１８】
（なお、一般式（４）中、Ｒ⁵ はアルキル基を表し、Ｒ⁶ は水素原子、シアノ基、カルバモイル基、カルボキシル基、エステル基またはアシル基を表し、ベンゼン環Ｋは置換基を有していてもよい。）
【化１４】

（なお、一般式（５）中、Ｒ ⁷ 、Ｒ ⁸ およびＲ ⁹ は水素原子または置換基を有してもよいアルキル基を表す。）〕
以下、本発明を詳細に説明する。
【００１９】
【発明の実施の形態】
本発明の感光層は少なくとも電荷発生物質および電荷移動物質を含有する。
さらに具体的な構成として、
（１）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、電荷移動物質およびバインダー樹脂を主成分とした電荷移動層をこの順に積層した積層型感光体
（２）導電性支持体上に電荷移動物質及びバインダー樹脂を主成分とする電荷移動層、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積層型感光体
【００２０】
これらの感光層は、浸漬コーティング、スプレーコーティング、マルチノズルコーティング、バーコーティング、ロールコーティング、スピンコーティング等の公知の方法によって導電性支持体上に形成される。
導電性支持体としては、種々公知のものが使用できる。例えば、アルミニウム、銅、ニッケル、ステンレススチール等の金属類；アルミニウム、チタニウム、ニッケル、クロム、金、酸化スズ、ＩＴＯ等の塗膜を設けたり、金属粉末、カーボンブラック、酸化スズ等の導電性物質を必要に応じてバインダー樹脂とともに塗布することにより導電性を付与したプラスチックフィルム類、紙類などが挙げられる。
【００２１】
これらの導電性支持体は、ドラム状、シート状、プレート状等、適宜の形状のものを選択することができるが、これらに限定されるものではない。
また、これらの導電性支持体の表面は、画像に悪影響を与えない範囲で各種の処理を行うことができる。例えば、砂目立て等の乱反射処理、薬品処理、着色処理、ブロッキング層の形成等が挙げられる。ブロッキング層としては、酸化アルミ；ポリアミド、ポリウレタン、フェノール樹脂等の樹脂層；また、これらの樹脂に適当な導電性を付与するために金属粒子等を分散させた樹脂層などが挙げられる。
【００２２】
また、感光層表面に必要に応じてポリアミド、熱硬化性シリコーン樹脂、架橋アクリル樹脂等よりなる保護層を設けていてもよい。
本発明に使用される電荷発生物質は、一般式（２）または（３）で表されるアゾ系化合物およびオキシチタニウムフタロシアニンである。
一般式（２）中、Ｚは一般式（２−ａ）または（２−ｂ）で表されるテトラゾ成分残基を表す。
【００２３】
【化１５】

【００２４】
一般式（２−ａ）、（２−ｂ）中、Ｒ^１ 、Ｒ^２ 、Ｒ^３ およびＲ^４ は水素原子；塩素原子、臭素原子等のハロゲン原子；メチル基、エチル基等のアルキル基；メトキシ基、エトキシ基等のアルコキシ基を表し、これらは互いに同一でも異なっていてもよい。
Ｇはベンゼン環と共に炭化水素環、ヘテロ環等の縮合環を形成する残基を表す。
【００２５】
Ｊは酸素原子、硫黄原子等のヘテロ原子、２価の炭化水素残基、ヘテロ環または２価の炭化水素残基とヘテロ環が連結した基を表す。但し、下記一般式（ｊ）で表される基を除く。
【００２６】
【化１６】

【００２７】
（式中、Ｒは水素原子または置換或いは未置換のアルキル基或いは複素環基であり、ｎは０または１である。）
一般式（２）および（３）中、Ｃｐ_１ 、Ｃｐ_２ 、Ｃｐ_３ 、Ｃｐ_４ 及びＣｐ_５ はカップラー残基を表す。但しＣｐ_１ およびＣｐ_２ が下記一般式（４）で表される基である場合を除く。
【００２８】
【化１７】

【００２９】
一般式（４）中、Ｒ⁵ はメチル基、エチル基等のアルキル基を表し、Ｒ⁶ は水素原子、シアノ基、カルバモイル基、カルボキシル基、エステル基またはアシル基を表し、ベンゼン環Ｋは置換基を有していてもよい。
一般式（２−ａ）、（２−ｂ）として好ましい構造を下記に示す。
【００３０】
【化１８】

【００３１】
【化１９】

【００３２】
次に、Ｃｐ_１ 、Ｃｐ_２ 、Ｃｐ_３ 、Ｃｐ_４ 及びＣｐ_５ のカップラー残基として好ましい例を以下に示す。
【００３３】
【表１】

【００３４】
【表２】

【００３５】
【表３】

【００３６】
【表４】

【００３７】
【表５】

【００３８】
【表６】

【００３９】
【表７】

【００４０】
【表８】

【００４１】
【表９】

【００４２】
【表１０】

【００４３】
【表１１】

【００４４】
次に、テトラゾ成分残基とカップラー残基の組合せとして特に好ましいアゾ系化合物の例を以下に挙げる。
【００４５】
【化２０】

【００４６】
【化２１】

【００４７】
【化２２】

【００４８】
【化２３】

【００４９】
【化２４】

【００５０】
【化２５】

【００５１】
オキシチタニウムフタロシアニン顔料としては、各種の結晶型のものを単独または混合して用いることができる。
好ましい例を下記に示す。
（１０−１）ＣｕＫα線によるＸ線回折スペクトルにおいてブラッグ角（２θ±０．２°）
９．２°、１３．１°、２０．７°、２６．２°、２７．１°に回折ピークを有するオキシチタニウムフタロシアニン（Ｘ線回折スペクトル図を図１に示す）（１０−２）ＣｕＫα線によるＸ線回折スペクトルにおいてブラッグ角（２θ±０．２°）
７．５°、１２．６°、１３．０°、２５．４°、２８．６°に回折ピークを有するオキシチタニウムフタロシアニン（Ｘ線回折スペクトル図を図２に示す）（１０−３）ＣｕＫα線によるＸ線回折スペクトルにおいてブラッグ角（２θ±０．２°）
７．４°、９．７°、２４．２°、２７．３°に回折ピークを有するオキシチタニウムフタロシアニン（Ｘ線回折スペクトル図を図３に示す）
【００５２】
これらの電荷発生物質は該感光体を使用するプロセスの光源の種類により選択することができる。すなわち、一般的に白色光源を用いるアナログ複写機においてはアゾ系顔料を用いることにより高感度な感光体が得られ、レーザー光源またはＬＥＤ光源を用いるプリンター、デジタル複写機においてはオキシチタニウムフタロシアニン顔料を用いることにより高感度な感光体が得られる。アゾ系顔料とオキシチタニウムフタロシアニンを混合して用いることにより、白色光源とレーザー光源またはＬＥＤ光源両方に感度を有する感光体を得ることができる。この場合、除電光として感光体への光疲労の影響が少ないＬＥＤ光源を使用することができる。
【００５３】
また、この他の無機、有機種々の電荷発生物質を混合して用いてもよい。
例えば、無機系の電荷発生物質としては無定型セレン、セレン−テルル合金、三方晶セレン、三セレン化ヒ素等のセレンを主成分とした各種合金材料；硫化カドミウム等のII−IV族化合物半導体材料；無定型シリコン、水素化シリコン等公知の材料が微粒子の状態で使用される。又、有機系の電荷発生物質として、ペリレン顔料、多環キノン類、キナクリドン顔料、インジゴ顔料、スクアリリウム塩などが使用できる。
【００５４】
電荷発生物質は積層構造の場合には電荷発生層を構成する主成分として使用され、例えば蒸着、スパッターの様な方法で成膜した均一な層として用いられてもよく、また微粒子の形でバインダー樹脂に分散された形で用いられてもよい。この場合バインダー樹脂としてはポリ酢酸ビニル、ポリアクリル酸エステル、メタクリレート樹脂、ポリビニルブチラール、ポリビニルホルマール等のポリビニルアセタール樹脂、フェノキシ樹脂、セルロースエステル、セルロースエーテル、ウレタン樹脂、エポキシ樹脂など各種バインダー樹脂が使用できる。これらのバインダー樹脂は単独または２種類以上混合して用いることができる。
特に好ましい例として下記の構造式で表される繰り返し単位を有するバインダー樹脂が挙げられる。
【００５５】
【化２６】

【００５６】
電荷発生物質とバインダー樹脂との組成比は任意であるが、電荷発生物質の比率が少なすぎると十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るため、通常重量比で１００対１０ないし５対１００の範囲が好ましい。またこの層には電荷移動物質が混合されていてもよい。電荷発生層の膜厚は、通常０．１μｍ〜１０μｍで使用されることが好ましい。また、前記のような分散型の感光層組成の場合には電荷発生物質は微粒子の形で電荷移動物質及びバインダー樹脂を有するマトリックス中に分散される。その場合、電荷発生物質の粒子径は十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。
本発明に使用される電荷移動物質は前述した通り、下記一般式（１）で表されるアリールアミン化合物を用いる。
【００５７】
【化２７】

【００５８】
一般式（１）中、ベンゼン環Ａ、Ｂ、ＣおよびＤはそれぞれ置換基を有していてもよく、ベンゼン環上の置換基としては、メチル基、エチル基、プロピル基等のアルキル基；フェニル基、トリル基等のアリール基等が挙げられる。
【００５９】
Ｙは置換基を有していてもよい−（ＣＨ_２ ）_５ −、−（ＣＨ_２ ）_６ −等のアルキレン基を表す。置換基としては、メチル基、エチル基等のアルキル基；メトキシ基、エトキシ基等のアルコキシ基等が挙げられる。
一般式（１）で表されるアリールアミン系化合物として特に好ましい化合物を以下に例示する。
【００６０】
【化２８】

【００６１】
【化２９】

【００６２】
一般式（１）で示されるアリールアミン系化合物は溶解性がやや劣り、結晶性が高いため、塗布液の固形分濃度が一定値を越えると塗布液中で結晶化が起こり、塗布液の保存安定性が劣る。固形分濃度が低いと、特に厚膜の感光層を塗布する際に均一な感光層を得ることが難しくなり生産性が落ちる。例えば、浸漬塗布を行った場合に所望の膜厚を得るためには素管引き上げ速度を上げる必要がありそのため塗布上端のタレ部が大きくなる。塗布液の保存安定性を満足させつつ固形分濃度をあげるためには一般式（１）の化合物の重量部を下げる必要があるが、その場合残留電位が上昇や、繰り返しの電気特性が悪化する弊害がある。この問題に対して、一般式（５）で表されるアリールアミン系化合物を混合することにより固形分濃度を上げることができ、電気特性が悪化させることなく膜厚を上げることができ、かつ塗布液の物性を満足することができる。
【００６３】
【化３０】

【００６４】
一般式（５）中、Ｒ⁷ 、Ｒ⁸、Ｒ⁹は水素原子またはメチル基、エチル基等のアルキル基を表す。
一般式（５）で表されるアリールアミン化合物として好ましい化合物を以下に例示する。
【００６５】
【化３１】

【００６６】
一般に、複数の電荷移動物質を混合して用いると、各々の電荷移動物質のイオン化ポテンシャルの差により各々の電荷移動物質を別々に使用した場合より残留電位が上昇する場合が見受けられるが、一般式（１）および一般式（５）で示される電荷移動物質を混合して用いた場合は、残留電位の上昇は認められない。しかし、一般式（５）で示される化合物を多量に用いると感光体の感度の低下を引き起こす。そのため、一般式（１）で示される化合物と一般式（５）で示される化合物の混合比率は１００：３０から１００：１００が好ましく、１００：５０から１００：８０がより好ましい。
【００６７】
また、他の電荷移動物質を混合して用いてもよい。具体的には、アリールアミン系化合物、スチルベン系化合物、ヒドラゾン系化合物等が挙げられる。
これらの電荷移動物質と共に使用されるバインダー樹脂としては種々の公知の樹脂が使用できる。具体的には、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、アクリル樹脂、メタクリレート樹脂、スチレン樹脂、シリコーン樹脂などの熱可塑性樹脂や硬化性の樹脂が使用できる。これらの樹脂は特に磨耗、傷の発生の少ないポリカーボネート樹脂、ポリアクリレート樹脂、ポリエステル樹脂が好ましい。これらのバインダー樹脂は単独または２種類以上混合して用いることができる。
本発明者らは、ポリカーボネート樹脂の構造についてさらに鋭意検討した結果、下記一般式（６）で表される繰り返し単位を含むポリカーボネート樹脂を用いた場合に特に高感度な感光体が得られることを見いだした。
【００６８】
【化３２】

【００６９】
（一般式（６）中、ベンゼン環ＬおよびＭは置換基を有していてもよく、置換基としてはメチル基、エチル基等のアルキル基；フェニル基、トリル基等のアリール基等が挙げられる。Ｒ¹⁰およびＲ¹¹は、メチル基、エチル基等のアルキル基；フェニル基、トリル基等のアリール基を表す。また、Ｒ¹⁰とＲ¹¹は縮合して炭素原子と共にシクロペンチル基、シクロヘキシル基等の炭化水素環を形成してもよい。）
一般式（６）で示される繰り返し単位の好ましい例を以下に示す。
【００７０】
【化３３】

【００７１】
次にバインダー樹脂として好ましい具体例を挙げる。
【００７２】
【化３４】

【００７３】
【化３５】

【００７４】
特に（７−４）で表されるバインダー樹脂を用いた場合、特に高感度な感光体が得られ好ましい。
電荷移動物質とバインダー樹脂の配合比率は、樹脂１００重量部に対して２０〜２００重量部、好ましくは４０〜１５０重量部、より好ましくは５０〜１００重量部の範囲で配合される。
【００７５】
積層感光体の場合電荷移動層として上記の成分を主成分として形成される。一般的に電荷移動層の膜厚を上げるほど高感度な感光体を得ることができる。しかし、それにつれて感光体の応答性の低下、残留電位の上昇といった弊害が発生する場合があるため、電荷移動層の膜厚としては通常５〜５０μｍ、好ましくは１０〜４０μｍ、より好ましくは１５〜３５μｍで使用される。
【００７６】
分散型の感光体の場合、上記のような配合比の電荷移動物質及びバインダー樹脂を主成分とするマトリックス中に電荷発生物質が微粒子で分散されるがその粒子径は十分小さいことが必要であり、好ましくは１ミクロン以下、より好ましくは０．５ミクロン以下で使用される。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十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。感光層の膜厚は通常５〜５０μｍ、より好ましくは１５〜４０μｍで使用される。
【００７７】
上記感光層に添加される、電子吸引性物質、酸化防止剤等は、公知の物が使用できる。電子吸引性物質としては、例えばクロラニル、２，３−ジクロロ−１，４−ナフトキノン、１−ニトロアントラキノン、１−クロロ−５−ニトロアントラキノン、２−クロロアントラキノン、フェナントレンキノン等のキノン類；４−ニトロベンズアルデヒド等のアルデヒド類；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、２，４，７−トリニトロフルオレノン、２，４，５，７−テトラニトロフルオレノン、３，３′，５，５′−テトラニトロベンゾフェノン等のケトン類；無水フタル酸、４−クロロナフタル酸無水物等の酸無水物；テトラシアノエチレン、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等のシアノ化合物；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−テトラクロロフタリド等のフタリド類等の電子吸引性化合物が挙げられる。
電子吸引性化合物として特に好ましい例を以下に列挙する。
【００７８】
【化３６】

【００７９】
酸化防止剤としては、ヒンダードフェノール系化合物、ヒンダードアミン系化合物などが挙げられる。
特に好ましい酸化防止剤の例を以下に挙げる。
【００８０】
【化３７】

【００８１】
【化３８】

【００８２】
【化３９】

【００８３】
また、成膜性、可とう性、機械的強度等を改良するための公知の可塑剤、分散安定性向上のための分散助剤、塗布性を改良するためのレベリング剤、界面活性剤、例えばシリコンオイル、フッ素系オイルその他の添加剤を添加してもよい。
塗布液調整用の溶剤としてはテトラヒドロフラン、１，４−ジオキサン等のエーテル類；メチルエチルケトン、シクロヘキサノン等のケトン類；トルエン、キシレン等の芳香族炭化水素；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等の非プロトン性極性溶媒；酢酸エチル、蟻酸メチル、メチルセロソルブアセテート等のエステル類；ジクロロエタン、クロロホルム等の塩素化炭化水素などのアリールアミン系化合物およびバインダー樹脂を溶解させる溶剤が挙げられる。また、塗布後の乾燥性を考慮し、低沸点の溶剤に比較的高沸点の溶剤を添加するなど、複数の溶剤を混合して用いてもよい。一方、感光体の生産性の観点からは塗布液の粘度は塗布方法に応じた適正な範囲内であることが望ましい。感光体の耐磨耗性を向上させる一つの手段として高分子量のバインダー樹脂を用いる方法があるが、バインダー樹脂の分子量を上げることによって塗布液の粘度も上昇し、適正な範囲を越えてしまう傾向がある。これに対して、芳香族炭化水素を用いると塗布液の粘度を低く抑えることができ好ましい。
【００８４】
【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、本発明はその要旨を越えない限り以下の実施例によって限定されるものではない。
実施例１
前記例示化合物（２−１２）のビスアゾ顔料１．４部と例示化合物（１１−１）のポリビニルブチラール樹脂（電気化学工業（株）社製＃６０００Ｃ）１．４部を４４部のメチルエチルケトン及び１５部の４−メトキシ−４−メチルペンタノン−２中で、サンドグラインダーミルにより、分散微粒子化処理を行った。
【００８５】
この様にして得られた分散液をポリエステルフィルム上に蒸着したアルミニウム蒸着面上にバーコーターによりその乾燥膜厚が０．４μｍとなるように電荷発生層を設けた。この電荷発生層上に、例示化合物（１−２）で示されるアリールアミン化合物を４０重量部、例示化合物（５−２）で示されるアリールアミン化合物３０重量部および例示化合物（７−６）で示されるポリカーボネート樹脂１００重量部をテトラヒドロフラン４５０重量部およびトルエン１００重量部に溶解させた溶液をフィルムアプリケーターにより乾燥後の膜厚が３０μｍになるように電荷移動層を設けた。この様にして作成した感光体を実施感光体１とする。
【００８６】
得られた感光体について静電複写紙試験装置（川口電機製作所製、モデルＥＰＡ−８１００）により電気特性の評価を行った。すなわち暗所で３５μＡのコロナ電流により感光体を負帯電させたあと（Ｖｏ）、白色光を連続的に照射し、表面電位が−７００Ｖから−３５０Ｖに減少するのに要した半減露光量（Ｅ1/2 ）および残留電位（Ｖｒ）を測定した。
Ｖｏ −９３９Ｖ、Ｅ1/2 ０．４４ １ｕｘ・ｓｅｃ、Ｖｒ −１Ｖであった。
【００８７】
実施例２
例示化合物（７−６）のポリカーボネート樹脂の代わりに例示化合物（７−２）のポリカーボネート樹脂を用いた以外は実施例１と同様にして実施感光体２を作成し、実施例１と同様に電気特性の評価を行った。結果を表２に示す。
実施例３
例示化合物（７−６）のポリカーボネート樹脂の代わりに例示化合物（７−４）のポリカーボネート樹脂を用いた以外は実施例１と同様にして実施感光体３を作成し、実施例１と同様に電気特性の評価を行った。結果を表２に示す。
【００８８】
実施例４
例示化合物（７−６）のポリカーボネート樹脂の代わりに例示化合物（７−５）のポリカーボネート樹脂を用いた以外は実施例１と同様にして実施感光体４を作成し、実施例１と同様に電気特性の評価を行った。結果を表２に示す。
【００８９】
【表１２】

【００９０】
実施例５
例示化合物（２−１）のビスアゾ顔料１．４部と例示化合物（１１−１）のポリビニルブチラール樹脂（電気化学工業（株）社製＃６０００Ｃ）０．７部、および例示化合物（１１−３）のフェノキシ樹脂０．７部を４４部のメチルエチルケトン及び１５部の４−メトキシ−４−メチルペンタノン−２中で、サンドグラインダーミルにより、分散微粒子化処理を行った。
【００９１】
この様にして得られた分散液をポリエステルフィルム上に蒸着したアルミニウム蒸着面上にバーコーターによりその乾燥膜厚が０．４μｍとなるように電荷発生層を設けた。
例示化合物（１−２）で示されるアリールアミン化合物３０重量部、例示化合物（５−
２）で示されるアリールアミン化合物３０重量部、例示化合物（７−４）のポリカーボネート樹脂１００重量部をテトラヒドロフラン４５０重量部およびトルエン１００重量部に溶解させた溶液をフィルムアプリケーターにより乾燥後の膜厚が３５μｍになるように電荷移動層を設けた。この様にして作成した感光体を実施感光体５とする。
得られた感光体について実施例１と同様にして電気特性の評価を行った。結果を表３に示す。
【００９２】
実施例６
例示化合物（２−１）のビスアゾ顔料の代わりに例示化合物（２−８）のビスアゾ顔料を用いた他は実施例５と同様にして実施感光体６を作成し電気特性の評価を行った。結
果を表３に示す。
【００９３】
実施例７
例示化合物（２−１）のビスアゾ顔料の代わりに例示化合物（２−９）のビスアゾ顔料を用いた他は実施例５と同様にして実施感光体７を作成し電気特性の評価を行った。結
果を表３に示す。
【００９４】
実施例８
例示化合物（２−１）のビスアゾ顔料の代わりに例示化合物（２−１３）のビスアゾ顔料を用いた他は実施例５と同様にして実施感光体８を作成し電気特性の評価を行った。
結果を表３に示す。
【００９５】
実施例９
例示化合物（２−１）のビスアゾ顔料の代わりに例示化合物（２−２１）のビスアゾ顔料を用いた他は実施例５と同様にして実施感光体９を作成し電気特性の評価を行った。
結果を表３示す。
【００９６】
【表１３】

【００９７】
実施例１０
実施例５において例示化合物（２−１）のビスアゾ顔料１．４部の代わりに、例示化合物（２−１２）のビスアゾ顔料１．１部および例示化合物（１０−１）のチタニルフタロシアニンを用いた以外は実施例５と同様にして実施感光体１０を作成した。
この感光体について実施例１と同様に白色光を照射して電気特性の測定を行ったところ、Ｖｏ −９０３Ｖ、Ｅ1/2 ０．４７ lux・sec 、Ｖｒ −２Ｖであった。また、静電複写紙試験装置（川口電機製作所製、モデルＥＰＡ−８１００）により、暗所で３５μＡのコロナ電流により感光体を負帯電させたあと（Ｖｏ）、７８０ｎｍの光を連続的に照射し、表面電位が−７００Ｖから−３５０Ｖに減少するのに要した半減露光量（Ｅ1/2）および残留電位（Ｖｒ）を測定したところ、Ｖｏ −９０３Ｖ、Ｅ1/2 ０．４１μＪ／ｃｍ^２ 、Ｖｒ −２Ｖであった。
【００９８】
実施例１１
例示化合物（２−１２）のアゾ化合物１．４部と例示化合物（１１−１）のポリビニルブチラール樹脂（電気化学工業（株）社製＃６０００Ｃ）０．７部、および例示化合物（１１−３）のフェノキシ樹脂０．７部を４４部のメチルエチルケトン及び１５部の４−メトキシ−４−メチルペンタノン−２中で、サンドグラインダーミルにより、分散微粒子化処理を行った。
【００９９】
この様にして得られた分散液をポリエステルフィルム上に蒸着したアルミニウム蒸着面上にバーコーターによりその乾燥膜厚が０．４μｍとなるように電荷発生層を設けた。
例示化合物（１−２）で示されるアリールアミン化合物３０重量部、例示化合物（５−２）で示されるアリールアミン化合物３０重量部、例示化合物（７−４）のポリカーボネート樹脂１００重量部、例示化合物（８−２）の電子吸引性化合物１０重量部をテトラヒドロフラン４５０重量部およびトルエン１００重量部に溶解させた溶液をフィルムアプリケーターにより乾燥後の膜厚が３０μｍになるように電荷移動層を設けた。この様にして作成した感光体を実施感光体１１とする。
得られた感光体について実施例１と同様にして電気特性の評価を行った。さらに同じ測定を１０００回繰り返して行った。結果を表４に示す。
【０１００】
【表１４】

【０１０１】
実施例１２
実施例３で作成した実施感光体３を用いて、実施例１１と同様に１０００回繰り返して電気特性の測定を行った。
結果を一回目の測定と共に表５に示す。
【０１０２】
【表１５】

【０１０３】
実施例１３
例示化合物（８−２）の電子吸引性化合物１０重量部の代わりに例示化合物（８−７）の電子吸引性化合物２部を用いた他は実施例１１と同様にして実施感光体１２を作成し、電気特性の測定を行った。結果を表６に示す。
【０１０４】
【表１６】

【０１０５】
実施例１４
実施例１１と同様にして電荷発生層を作成した。この上に、例示化合物（１−２）で示されるアリールアミン化合物３０重量部、例示化合物（５−２）で示されるアリールアミン化合物３０重量部、例示化合物（７−４）のポリカーボネート樹脂１００重量部、例示化合物（９−１）のフェノール系酸化防止剤１０重量部をテトラヒドロフラン４５０重量部およびトルエン１００重量部に溶解させた溶液をフィルムアプリケーターにより乾燥後の膜厚が３０μｍになるように電荷移動層を設けた。この様にして作成した感光体を実施感光体１３とする。
実施例１１と同様にして測定を行った結果を表７に示す。
【０１０６】
【表１７】

【０１０７】
実施例１５
実施例１１と同様にして電荷発生層を作成した。この上に、例示化合物（１−２）で示されるアリールアミン化合物３０重量部、例示化合物（５−２）で示されるアリールアミン化合物３０重量部、例示化合物（７−４）のポリカーボネート樹脂１００重量部、例示化合物（９−１）のフェノール系酸化防止剤１０重量部および例示化合物（８−７）の電子吸引性化合物２部をテトラヒドロフラン４５０重量部およびトルエン１００重量部に溶解させた溶液をフィルムアプリケーターにより乾燥後の膜厚が３０μｍになるように電荷移動層を設けた。この様にして作成した感光体を実施感光体１４とする。
実施例１１と同様にして測定を行った結果を表８に示す。
【０１０８】
【表１８】

【０１０９】
参考例１
例示化合物（１−２）で示されるアリールアミン化合物３５重量部、例示化合物（５−２）で示されるアリールアミン化合物２５重量部、例示化合物（７−４）のポリカーボネート樹脂１００重量部（三菱ガス化学製 Ｚ−３００）、テトラヒドロフラン４００重量部およびトルエン１７０重量部に溶解させた。この溶液の粘度は２０４ｃＰｓであった。この溶液に直径３０ｍｍ、長さ３５０ｍｍ、肉厚１ｍｍのアルミシリンダーを用いて浸漬塗布によって乾燥膜厚２５ミクロンの塗膜を形成することができた。
また、この溶液を密封下５℃で３０日間静置したが液性の変化は認められなかった。
【０１１０】
実施例１６
実施例５で用いた例示化合物（１−２）のアリールアミン化合物のかわりに例示化合物（１−３）のアリールアミン化合物を用いた他は実施例５と同様にして実施感光体１５を作成し、実施例５と同様に電気特性の評価を行った。結果を表９に示す。
【０１１１】
実施例１７
実施例５で用いた例示化合物（１−２）のアリールアミン化合物のかわりに例示化合物（１−７）のアリールアミン化合物を用いた他は実施例５と同様にして実施感光体１６を作成し、実施例５と同様に電気特性の評価を行った。結果を表９に示す。
【０１１２】
【表１９】

【０１１３】
参考例２
参考例１において、トルエン１７０重量部のかわりに１，４−ジオキサン１７０重量部を用いた他は同様にして溶液を作成した。この溶液の粘度は、３１６ｃＰｓ
であった。この溶液に直径３０ｍｍ、長さ３５０ｍｍ、肉厚１ｍｍのアルミシリンダーを用いて浸漬塗布によって乾燥膜厚２５ミクロンの塗膜の形成を試みたが、アルミシリンダーの引き上げ速度が遅く、途中でアルミシリンダー内の気体が膨張し、シリンダー内からあふれ溶液中を浮遊する現象が起こった（いわゆる下ぼこ）。そのため、得られた塗膜はトルエンを用いた場合に比較して膜厚の均一性が劣っていた。
【０１１４】
参考例３
参考例１において、例示化合物（１−２）で示されるアリールアミン化合物３５重量部および例示化合物（５−２）で示されるアリールアミン化合物２５重量部の代わりに、前記例示化合物（１−２）で示されるアリールアミン化合物６０重量部を用いた他は参考例１と同様にして溶液を作成した。この溶液の粘度は２１２ｃＰｓであった。この溶液を５℃で静置したところ、３日でアリールアミン化合物の析出が認められた。
【０１１５】
比較例１〜５
実施例５〜１０において例示化合物（１−２）で示されるアリールアミン化合物３０重量部および例示化合物（５−２）で示されるアリールアミン化合物３０重量部の代わりに、下記構造式で示されるアリールアミン化合物６０重量部を用いた他は、それぞれ実施例５〜１０と同様にしてそれぞれ比較感光体１〜５を作成して電気特性を測定した。結果を表１０に示す。
【０１１６】
【化４０】

【０１１７】
【表２０】

【０１１８】
【発明の効果】
本発明の電子写真感光体は、高感度、低残留電位、高耐久性等に優れた、電子写真特性を有し、システムから発生するオゾン、窒素酸化物の影響を受けにくく、繰り返し使用しても安定した特性および画質を有しきわめて高い耐久性をもつ感光体である利点を有する。
本発明の感光体は、アナログ複写機、デジタル複写機、プリンターなど、電子写真の広い応用分野に用いる事ができる。
【図面の簡単な説明】
【図１】 本発明で使用するオキシチタニウムフタロシアニン顔料のＸ線回折スペクトル図である。
【図２】 本発明で使用するオキシチタニウムフタロシアニン顔料のＸ線回折スペクトル図である。
【図３】 本発明で使用するオキシチタニウムフタロシアニン顔料のＸ線回折スペクトル図である。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an electrophotographic photoreceptor. Specifically, it is extremely sensitive and durableStacked electrophotographyThe present invention relates to a photoreceptor.
[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 fields of various printers, facsimiles, and multi-function machines because of the availability of immediacy and high-quality images. As for photoconductors, which are the core of electrophotography, as photoconductive materials, inorganic photoconductors such as selenium, arsenic-selenium alloys, cadmium sulfide, and zinc oxide have been conventionally used. A photoreceptor using an organic photoconductive material having advantages such as ease has been developed.
[0003]
  Among organic photoconductors, a so-called laminated type photoconductor in which a charge generation layer and a charge transfer layer are laminated has been devised, and a highly sensitive photoconductor can be obtained by combining a charge generation material and a charge transfer material with high efficiency, respectively. Since a wide range of materials can be selected and a highly safe photoconductor can be obtained, and the productivity of coating is high and relatively advantageous in terms of cost, the photoconductor is becoming mainstream.
[0004]
  However, for use as a high-speed machine, the photosensitivity is insufficient in terms of electrical characteristics, the residual potential is high, the photoresponsiveness is poor, the chargeability decreases when used repeatedly, and the residual potential accumulates. It has various problems such as fluctuations in sensitivity, and it cannot be said that it still has sufficient characteristics. Among them, the development of a higher sensitivity photoconductor is widely desired for use in high-speed copying machines, printers, and the like. For example, in the case of a laminated photoconductor, the photosensitivity of the photoconductor greatly depends on the carrier generation efficiency due to the light absorption of the charge generating agent. At the same time, it is greatly affected by the matching with the charge transfer agent. This is because the sensitivity is closely related to the carrier injection efficiency from the charge generating agent to the charge transfer agent, the charge transfer efficiency in the charge transfer layer, and the like. Therefore, in order to achieve higher sensitivity, it is important to use a combination of a charge generating agent and a charge transfer agent simultaneously with the development of individual materials. Examples of the charge generation material have been disclosed in, for example, JP-A-55-117151, JP-A-57-176055, JP-A-61-109056 and JP-A-2-8256, and also charge transfer materials. For example, JP-A-54-150128, JP-A-56-13939, JP-A-58-159536, JP-A-59-15251, JP-A-58-198043, and Japanese Patent Publication No. 63-19867 and the combination of the charge generation material and the charge transfer material, for example, JP-A-1-253754, JP-A-5-204170, etc. Is disclosed.
[0005]
[Problems to be solved by the invention]
  However, the layered photoreceptors currently used generally are still inferior to inorganic photoreceptors in sensitivity and durability, and the present situation is that inorganic photoreceptors are still mainstream in high-speed machines.
  The sensitivity of multilayer photoconductors is affected by the efficiency of charge generation materials and charge transfer materials, but the combination of both is important, and high sensitivity is manifested specifically only in certain combinations. There is a case. Moreover, since sensitivity is also affected by the binder polymer of the charge transfer layer, it is not easy to find an optimal combination from these. Causes of inferior durability include reduction in charging potential, accumulation of residual potential, fluctuation in sensitivity, etc. in terms of electrical characteristics when used repeatedly. These are due to film loss due to wear of the photosensitive layer and impurities in the charge transfer layer.
[0006]
  The reduction of the photosensitive layer may be due to electrophotographic process cleaning, developing material, or abrasion due to paper dust. In order to reduce such film loss, it is important to improve the wear resistance of the surface of the photosensitive layer. The structure of the binder polymer in the charge transfer layer, the molecular weight, the ratio of the binder polymer to the charge transfer material, etc. are studied. Has been. Using a high molecular weight binder polymer is one method, but in this case, the viscosity of the coating solution increases, so when performing dip coating, which is the most common method for coating photoreceptors, production is accompanied by a decrease in coating speed. There arises a problem that the performance is significantly reduced. Further, when the ratio of the charge transfer material to the binder polymer is decreased, the abrasion resistance of the surface of the photosensitive layer is improved, but the sensitivity of the photoreceptor is lowered.
[0007]
  Impurities in the charge transfer layer are originally present in the composition, generated by corona discharge, repeatedly exposed to light from image exposure, static elimination lamps, etc., and further exposed to external light during maintenance, etc. It can be considered that deterioration occurs due to.
  That is, it is considered that such an impurity becomes a trap and traps a carrier to form a residual charge by forming a space charge that cannot move.
[0008]
  Attempts have been made to add an electron-withdrawing substance to the charge transfer layer as one of the means for suppressing the residual potential considered to be caused by such traps in the charge transfer layer.
  In general, when an electron-withdrawing substance is added to an electron-donating compound, a charge transfer complex is formed and a new wavelength appears on the long wavelength side. Therefore, when light corresponding to the absorption band of the charge transfer complex is irradiated, a slight but movable carrier is generated in the charge transfer layer, and as a result, the space charge that does not move is neutralized and the residual potential is suppressed. I think that. However, unless the addition amount of the electron-withdrawing substance is optimized, there are many cases where the residual potential is not sufficiently suppressed, and there are adverse effects such as an increase in dark decay, a decrease in surface potential in repeated use, and a decrease in sensitivity.
[0009]
[Means for Solving the Problems]
  Therefore, as a result of intensive studies on an electrophotographic photosensitive member having high sensitivity and excellent durability, the present inventors have found that excellent sensitivity is exhibited by using a specific charge transfer material and a charge generation material in combination. It was. Furthermore, it has been found that an excellent durability can be obtained by adding an appropriate amount of a specific electron-withdrawing substance and / or an antioxidant, and that a higher sensitivity can be achieved by combining with a specific binder resin. Moreover, it discovered that productivity could be improved by using a specific aromatic hydrocarbon as a charge transfer layer coating solvent.
[0010]
  That is, the gist of the present invention is the following general formula (1) on a conductive substrate.And (5)Arylamine compounds represented byA charge transfer layer containingContains an azo compound represented by the following general formula (2) or (3)With charge generation layerPhotosensitive layer or theCharge generationAnd an electrophotographic laminated photoreceptor having a photosensitive layer containing titanyl phthalocyanine, and a charge transfer layer of the photosensitive layer formed by coating using an aromatic hydrocarbon as a coating solvent. The feature resides in a multilayer electrophotographic photosensitive member.
[0011]
[Chemical Formula 10]

[0012]
[In General Formula (1), each of benzene rings A, B, C and D may have an alkyl group or an aryl group as a substituent, and Y represents an alkylene group which may have a substituent. .
  In the general formulas (2) and (3), Z represents a tetrazo component residue represented by the following general formula (2-a) or (2-b),
[0013]
Embedded image

[0014]
  In general formulas (2-a) and (2-b), R¹, R², R³And R⁴Represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, which may be the same or different from each other, G represents a residue which forms a condensed ring with a benzene ring, J represents a heteroatom, a divalent carbonization A hydrogen group, a heterocycle, or a divalent hydrocarbon group and a group in which a heterocycle is linked are represented. However, the group represented by the following general formula (j) is excluded.
[0015]
Embedded image

[0016]
(In the formula, R is a hydrogen atom, a substituted or unsubstituted alkyl group or a heterocyclic group, and n is 0 or 1.)
  Cp₁, Cp₂, Cp₃, Cp₄And Cp₅Each represents a coupler residue
The However, Cp₁And Cp₂Except when is a group represented by the following general formula (4)
.
[0017]
Embedded image

[0018]
(In the general formula (4), R^Five Represents an alkyl group, R⁶ Represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group, an ester group or an acyl group, and the benzene ring K may have a substituent. )
[Chemical14]

(In the general formula (5), R ⁷ , R ⁸ And R ⁹ Represents a hydrogen atom or an alkyl group which may have a substituent. )]
  Hereinafter, the present invention will be described in detail.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
  The photosensitive layer of the present invention contains at least a charge generating substance and a charge transfer substance.
  As a more specific configuration,
(1) A laminated photoreceptor in which a charge generation layer mainly composed of a charge generation material, a charge transfer material mainly composed of a charge transfer material and a charge transfer layer mainly composed of a binder resin are laminated in this order on a conductive support.
(2) A reverse two-layer laminated type photoreceptor in which a charge transfer layer mainly composed of a charge transfer substance and a binder resin and a charge generation layer mainly composed of a charge generation substance are laminated in this order on a conductive support.
[0020]
  These photosensitive layers are formed on a conductive support by known methods such as dip coating, spray coating, multi-nozzle coating, bar coating, roll coating, spin coating and the like.
  Various known materials can be used as the conductive support. For example, metals such as aluminum, copper, nickel, and stainless steel; coatings such as aluminum, titanium, nickel, chromium, gold, tin oxide, and ITO, and conductive materials such as metal powder, carbon black, and tin oxide Examples thereof include plastic films and papers imparted with conductivity by coating with a binder resin as necessary.
[0021]
  As these conductive supports, those having an appropriate shape such as a drum shape, a sheet shape, and a plate shape can be selected, but are not limited thereto.
  In addition, the surface of these conductive supports can be subjected to various treatments within a range that does not adversely affect the image. Examples thereof include irregular reflection treatment such as graining, chemical treatment, coloring treatment, and formation of a blocking layer. Examples of the blocking layer include aluminum oxide; resin layers such as polyamide, polyurethane, and phenol resin; and resin layers in which metal particles and the like are dispersed in order to impart appropriate conductivity to these resins.
[0022]
  Further, a protective layer made of polyamide, thermosetting silicone resin, cross-linked acrylic resin or the like may be provided on the photosensitive layer surface as necessary.
  The charge generating material used in the present invention is an azo compound represented by the general formula (2) or (3) and oxytitanium phthalocyanine.
  In general formula (2), Z represents a tetrazo component residue represented by general formula (2-a) or (2-b).
[0023]
[Chemical15]

[0024]
  In general formulas (2-a) and (2-b), R¹, R², R³And R⁴Represents a hydrogen atom; a halogen atom such as a chlorine atom or a bromine atom; an alkyl group such as a methyl group or an ethyl group; an alkoxy group such as a methoxy group or an ethoxy group, which may be the same or different.
  G represents a residue that forms a condensed ring such as a hydrocarbon ring or a hetero ring together with a benzene ring.
[0025]
  J represents a hetero atom such as an oxygen atom or a sulfur atom, a divalent hydrocarbon residue, a hetero ring or a group in which a divalent hydrocarbon residue and a hetero ring are linked. However, the group represented by the following general formula (j) is excluded.
[0026]
[Chemical16]

[0027]
(In the formula, R is a hydrogen atom, a substituted or unsubstituted alkyl group or a heterocyclic group, and n is 0 or 1.)
  In general formulas (2) and (3), Cp₁, Cp₂, Cp₃, Cp₄And Cp₅Represents a coupler residue. However, Cp₁And Cp₂Is a group represented by the following general formula (4).
[0028]
[Chemical17]

[0029]
  In general formula (4), R^Five Represents an alkyl group such as a methyl group or an ethyl group, and R⁶ Represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group, an ester group or an acyl group, and the benzene ring K may have a substituent.
  Preferred structures as general formulas (2-a) and (2-b) are shown below.
[0030]
[Chemical18]

[0031]
[Chemical19]

[0032]
  Next, Cp₁, Cp₂, Cp₃, Cp₄And Cp₅Preferred examples of the coupler residue are shown below.
[0033]
[Table 1]

[0034]
[Table 2]

[0035]
[Table 3]

[0036]
[Table 4]

[0037]
[Table 5]

[0038]
[Table 6]

[0039]
[Table 7]

[0040]
[Table 8]

[0041]
[Table 9]

[0042]
[Table 10]

[0043]
[Table 11]

[0044]
  Next, examples of particularly preferred azo compounds as combinations of tetrazo component residues and coupler residues are given below.
[0045]
[Chemical20]

[0046]
[Chemical21]

[0047]
[Chemical22]

[0048]
[Chemical23]

[0049]
[Chemical24]

[0050]
[Chemical25]

[0051]
  As the oxytitanium phthalocyanine pigment, various crystal types can be used alone or in combination.
  Preferred examples are shown below.
(10-1) Bragg angle (2θ ± 0.2 °) in X-ray diffraction spectrum by CuKα ray
  Oxytitanium phthalocyanine having diffraction peaks at 9.2 °, 13.1 °, 20.7 °, 26.2 °, 27.1 ° (X-ray diffraction spectrum is shown in FIG. 1) (10-2) CuKα Bragg angle (2θ ± 0.2 °) in X-ray diffraction spectrum by X-ray
  Oxytitanium phthalocyanine having diffraction peaks at 7.5 °, 12.6 °, 13.0 °, 25.4 °, and 28.6 ° (X-ray diffraction spectrum is shown in FIG. 2) (10-3) CuKα Bragg angle (2θ ± 0.2 °) in X-ray diffraction spectrum by X-ray
  Oxytitanium phthalocyanine having diffraction peaks at 7.4 °, 9.7 °, 24.2 °, and 27.3 ° (an X-ray diffraction spectrum diagram is shown in FIG. 3)
[0052]
  These charge generation materials can be selected depending on the type of light source of the process using the photoconductor. That is, in general, an analog copying machine using a white light source can obtain a highly sensitive photoreceptor by using an azo pigment, and a printer using a laser light source or an LED light source, or an oxytitanium phthalocyanine pigment in a digital copying machine As a result, a highly sensitive photoreceptor can be obtained. By using a mixture of an azo pigment and oxytitanium phthalocyanine, a photoreceptor having sensitivity to both a white light source and a laser light source or an LED light source can be obtained. In this case, an LED light source that is less affected by light fatigue on the photoconductor can be used as the static elimination light.
[0053]
  In addition, other inorganic and organic various charge generation materials may be mixed and used.
  For example, inorganic charge generation materials include amorphous selenium, selenium-tellurium alloy, trigonal selenium, arsenic triselenium and other various alloy materials; cadmium sulfide and other II-IV group compound semiconductor materials A known material such as amorphous silicon or silicon hydride is used in the form of fine particles. In addition, perylene pigments, polycyclic quinones, quinacridone pigments, indigo pigments, squarylium salts, and the like can be used as organic charge generating substances.
[0054]
  In the case of a laminated structure, the charge generating material is used as a main component constituting the charge generating layer, and may be used as a uniform layer formed by a method such as vapor deposition or sputtering, or may be used in the form of fine particles. You may use in the form disperse | distributed to resin. In this case, various binder resins such as polyvinyl acetate, polyacrylic acid ester, methacrylate resin, polyvinyl acetal resin such as polyvinyl butyral, polyvinyl formal, phenoxy resin, cellulose ester, cellulose ether, urethane resin, and epoxy resin can be used as the binder resin. . These binder resins can be used alone or in combination of two or more.
  Particularly preferred examples include binder resins having a repeating unit represented by the following structural formula.
[0055]
[Chemical26]

[0056]
  The composition ratio of the charge generation material and the binder resin is arbitrary. However, if the ratio of the charge generation material is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. In general, the range of 100 to 10 to 5 to 100 is preferred by weight ratio. Further, a charge transfer substance may be mixed in this layer. It is preferable that the charge generation layer has a thickness of usually 0.1 μm to 10 μm. In the case of the dispersion type photosensitive layer composition as described above, the charge generating material is dispersed in a matrix having a charge transfer material and a binder resin in the form of fine particles. In that case, the particle size of the charge generation material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less.
  As described above, the arylamine compound represented by the following general formula (1) is used as the charge transfer material used in the present invention.
[0057]
[Chemical27]

[0058]
  In general formula (1), benzene rings A, B, CandEach D may have a substituent, and examples of the substituent on the benzene ring include an alkyl group such as a methyl group, an ethyl group, and a propyl group; and an aryl group such as a phenyl group and a tolyl group.
[0059]
  Y may have a substituent — (CH₂)₅-,-(CH₂)₆Represents an alkylene group such as-. Examples of the substituent include alkyl groups such as a methyl group and an ethyl group; alkoxy groups such as a methoxy group and an ethoxy group.
  Particularly preferred compounds as the arylamine compound represented by the general formula (1) are exemplified below.
[0060]
[Chemical28]

[0061]
[Chemical29]

[0062]
  The arylamine compound represented by the general formula (1) has slightly poor solubility and high crystallinity. Therefore, when the solid content concentration of the coating solution exceeds a certain value, crystallization occurs in the coating solution and the coating solution is stored. Stability is inferior. When the solid content concentration is low, it is difficult to obtain a uniform photosensitive layer particularly when a thick photosensitive layer is applied, and productivity is lowered. For example, in order to obtain a desired film thickness when dip coating is performed, it is necessary to increase the speed of pulling up the raw tube, so that the sagging portion at the upper end of the coating becomes large. In order to increase the solid concentration while satisfying the storage stability of the coating solution, it is necessary to lower the weight part of the compound of the general formula (1). In this case, the residual potential is increased or the repeated electrical characteristics are deteriorated. There are harmful effects. For this problem, the solid content concentration can be increased by mixing the arylamine compound represented by the general formula (5), the film thickness can be increased without deteriorating the electrical characteristics, and the coating can be performed. The physical properties of the liquid can be satisfied.
[0063]
[Chemical30]

[0064]
  In general formula (5), R⁷ , R⁸, R⁹Represents a hydrogen atom or an alkyl group such as a methyl group or an ethyl group.
  General formula (5)Represented byPreferred compounds as the arylamine compound are exemplified below.
[0065]
[Chemical31]

[0066]
  In general, when a plurality of charge transfer materials are used in combination, the residual potential may be higher than when each charge transfer material is used separately due to the difference in ionization potential of each charge transfer material. When the charge transfer materials represented by (1) and general formula (5) are mixed and used, no increase in residual potential is observed. However, when a large amount of the compound represented by the general formula (5) is used, the sensitivity of the photoreceptor is lowered. Therefore, the mixing ratio of the compound represented by the general formula (1) and the compound represented by the general formula (5) is preferably 100: 30 to 100: 100, and more preferably 100: 50 to 100: 80.
[0067]
  Further, other charge transfer materials may be mixed and used. Specific examples include arylamine compounds, stilbene compounds, hydrazone compounds, and the like.
  Various known resins can be used as the binder resin used together with these charge transfer materials. Specifically, thermoplastic resins and curable resins such as polycarbonate resins, polyester resins, polyarylate resins, acrylic resins, methacrylate resins, styrene resins, and silicone resins can be used. These resins are particularly preferably polycarbonate resins, polyacrylate resins, and polyester resins with less wear and scratches. These binder resins can be used alone or in combination of two or more.
  As a result of further intensive studies on the structure of the polycarbonate resin, the present inventors have found that a particularly sensitive photoconductor can be obtained when a polycarbonate resin containing a repeating unit represented by the following general formula (6) is used. It was.
[0068]
[Chemical32]

[0069]
(In the general formula (6), the benzene rings L and M may have a substituent, and examples of the substituent include an alkyl group such as a methyl group and an ethyl group; and an aryl group such as a phenyl group and a tolyl group) R^TenAnd R¹¹Represents an alkyl group such as a methyl group or an ethyl group; and an aryl group such as a phenyl group or a tolyl group. R^TenAnd R¹¹May be condensed to form a hydrocarbon ring such as a cyclopentyl group or a cyclohexyl group together with a carbon atom. )
  Preferred examples of the repeating unit represented by the general formula (6) are shown below.
[0070]
[Chemical33]

[0071]
  Next, a specific example preferable as a binder resin is given.
[0072]
[Chemical34]

[0073]
[Chemical35]

[0074]
  In particular, when the binder resin represented by (7-4) is used, a particularly high-sensitivity photoreceptor is obtained, which is preferable.
  The mixing ratio of the charge transfer substance and the binder resin is 20 to 200 parts by weight, preferably 40 to 150 parts by weight, and more preferably 50 to 100 parts by weight with respect to 100 parts by weight of the resin.
[0075]
  In the case of a laminated photoreceptor, the charge transfer layer is formed with the above components as the main components. Generally, the higher the thickness of the charge transfer layer, the higher the sensitivity of the photoconductor can be obtained. However, there are cases in which adverse effects such as a decrease in the responsiveness of the photoreceptor and an increase in the residual potential may occur. Therefore, the thickness of the charge transfer layer is usually 5 to 50 μm, preferably 10 to 40 μm, more preferably 15 to Used at 35 μm.
[0076]
  In the case of a dispersion type photoconductor, the charge generation material is dispersed in fine particles in a matrix mainly composed of the charge transfer material and the binder resin having the above-mentioned mixing ratio, but the particle diameter must be sufficiently small. , Preferably 1 micron or less, more preferably 0.5 micron or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained. If the amount is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. For example, preferably 0.5 to 50 It is used in the range of wt%, more preferably in the range of 1 to 20 wt%. The film thickness of the photosensitive layer is usually 5 to 50 μm, more preferably 15 to 40 μm.
[0077]
  Known materials can be used as the electron-withdrawing substance, the antioxidant and the like added to the photosensitive layer. Examples of the electron-withdrawing substance include quinones such as chloranil, 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, and phenanthrenequinone; Aldehydes such as nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 3,3 ', 5 Ketones such as 5,5'-tetranitrobenzophenone; acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; tetracyanoethylene, terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitroben Zalmalononitrile, 4- (p-nitrobenzoy Cyano compounds such as oxy) benzalmalononitrile; 3-benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,5,6,7-tetrachloro Examples thereof include electron-withdrawing compounds such as phthalides such as phthalide.
  Particularly preferred examples of the electron withdrawing compound are listed below.
[0078]
[Chemical36]

[0079]
  Examples of the antioxidant include hindered phenol compounds and hindered amine compounds.
  Examples of particularly preferred antioxidants are listed below.
[0080]
[Chemical37]

[0081]
[Chemical38]

[0082]
[Chemical39]

[0083]
  Also, known plasticizers for improving film formability, flexibility, mechanical strength, etc., dispersion aids for improving dispersion stability, leveling agents for improving coatability, surfactants, for example Silicon oil, fluorine oil and other additives may be added.
  Solvents for adjusting the coating solution include ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N, N-dimethylformamide, acetonitrile, N-methyl Examples include aprotic polar solvents such as pyrrolidone and dimethyl sulfoxide; esters such as ethyl acetate, methyl formate and methyl cellosolve acetate; arylamine compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform; and solvents that dissolve binder resins It is done. In consideration of drying properties after coating, a plurality of solvents may be mixed and used, such as adding a relatively high boiling point solvent to a low boiling point solvent. On the other hand, from the viewpoint of photoreceptor productivity, the viscosity of the coating solution is preferably within an appropriate range according to the coating method. One way to improve the abrasion resistance of the photoreceptor is to use a high molecular weight binder resin, but increasing the binder resin molecular weight also increases the viscosity of the coating solution and tends to exceed the proper range. There is. On the other hand, it is preferable to use aromatic hydrocarbon because the viscosity of the coating solution can be kept low.
[0084]
【Example】
  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited by a following example, unless the summary is exceeded.
Example1
  1.4 parts of the bisazo pigment of the exemplified compound (2-12) and 1.4 parts of polyvinyl butyral resin (# 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) of the exemplified compound (11-1) and 44 parts of methyl ethyl ketone and 15 Part of 4-methoxy-4-methylpentanone-2 was subjected to dispersion fine particle treatment by a sand grinder mill.
[0085]
  A charge generation layer was provided on the aluminum vapor deposition surface on which the dispersion thus obtained was vapor deposited on a polyester film by a bar coater so that the dry film thickness was 0.4 μm. On the charge generation layer, 40 parts by weight of the arylamine compound represented by the exemplified compound (1-2), 30 parts by weight of the arylamine compound represented by the exemplified compound (5-2), and the exemplified compound (7-6) A charge transfer layer was provided so that the film thickness after drying a solution obtained by dissolving 100 parts by weight of the polycarbonate resin in 450 parts by weight of tetrahydrofuran and 100 parts by weight of toluene with a film applicator was 30 μm. The photoreceptor thus prepared is used as a photoreceptor.1And
[0086]
  The obtained photoreceptor was evaluated for electric characteristics by an electrostatic copying paper testing apparatus (model EPA-8100, manufactured by Kawaguchi Electric Mfg. Co., Ltd.). That is, after negatively charging the photoconductor with a corona current of 35 μA in a dark place (Vo), a half-exposure amount (E1) required to continuously irradiate white light and reduce the surface potential from −700 V to −350 V. / 2) and residual potential (Vr).
  Vo-939V, E1 / 2 0.44 1 ux.sec, Vr-1V.
[0087]
Example2
  Example except that polycarbonate resin of exemplary compound (7-2) was used instead of polycarbonate resin of exemplary compound (7-6)1Conductor in the same manner as2Create an example1The electrical characteristics were evaluated in the same manner as described above. Table the results2Shown in
Example3
  Example except that polycarbonate resin of exemplary compound (7-4) was used instead of polycarbonate resin of exemplary compound (7-6)1Conductor in the same manner as3Create an example1The electrical characteristics were evaluated in the same manner as described above. Table the results2Shown in
[0088]
Example4
  Example except that polycarbonate resin of exemplary compound (7-5) was used instead of polycarbonate resin of exemplary compound (7-6)1Conductor in the same manner as4Create an example1The electrical characteristics were evaluated in the same manner as described above. Table the results2Shown in
[0089]
[Table 12]

[0090]
Example5
  1.4 parts of the bisazo pigment of Exemplified Compound (2-1), 0.7 part of polyvinyl butyral resin (# 6000C manufactured by Denki Kagaku Kogyo Co., Ltd.) of Exemplified Compound (11-1), and Exemplified Compound (11-3) The phenoxy resin (0.7 part) was dispersed in 44 parts of methyl ethyl ketone and 15 parts of 4-methoxy-4-methylpentanone-2 using a sand grinder mill.
[0091]
  A charge generation layer was provided on the aluminum vapor deposition surface on which the dispersion thus obtained was vapor-deposited on a polyester film by a bar coater so that the dry film thickness was 0.4 μm.
  30 parts by weight of an arylamine compound represented by the exemplary compound (1-2), an exemplary compound (5-
The film thickness after drying a solution obtained by dissolving 30 parts by weight of the arylamine compound represented by 2), 100 parts by weight of the polycarbonate resin of the exemplary compound (7-4) in 450 parts by weight of tetrahydrofuran and 100 parts by weight of toluene by a film applicator. A charge transfer layer was provided so as to have a thickness of 35 μm. The photoreceptor thus prepared is used as a photoreceptor.5And
  Examples of the obtained photoreceptor1In the same manner, the electrical characteristics were evaluated. Table the results3Shown in
[0092]
Example6
  Except that the bisazo pigment of the exemplified compound (2-8) was used in place of the bisazo pigment of the exemplified compound (2-1), Example5Conductor in the same manner as6The electrical characteristics were evaluated. Result
Table3Shown in
[0093]
Example7
  Except that the bisazo pigment of the exemplified compound (2-9) was used in place of the bisazo pigment of the exemplified compound (2-1), Example5Conductor in the same manner as7The electrical characteristics were evaluated. Result
Table3Shown in
[0094]
Example8
  Except that the bisazo pigment of the exemplified compound (2-13) was used in place of the bisazo pigment of the exemplified compound (2-1), Example5Conductor in the same manner as8The electrical characteristics were evaluated.
Table the results3Shown in
[0095]
Example9
  Example except that the bisazo pigment of the exemplified compound (2-21) was used in place of the bisazo pigment of the exemplified compound (2-1)5Conductor in the same manner as9The electrical characteristics were evaluated.
Table the results3Show.
[0096]
[Table 13]

[0097]
Example10
  Example5In Example 1, except that 1.1 parts of the bisazo pigment of the exemplary compound (2-12) and titanyl phthalocyanine of the exemplary compound (10-1) were used instead of 1.4 parts of the bisazo pigment of the exemplary compound (2-1). Example5Conductor in the same manner as10It was created.
  When this photoreceptor was irradiated with white light in the same manner as in Example 1 and the electrical characteristics were measured, it was Vo-903V, E1 / 2 0.47 lux.sec, and Vr-2V. In addition, the photosensitive member was negatively charged with a corona current of 35 μA in a dark place by an electrostatic copying paper testing apparatus (model EPA-8100, manufactured by Kawaguchi Electric Manufacturing Co., Ltd.) (Vo), and then continuously irradiated with 780 nm light. The half-exposure amount (E1 / 2) and the residual potential (Vr) required for the surface potential to decrease from -700 V to -350 V were measured. Vo-903 V, E1 / 2 0.41 μJ / cm²Vr-2V.
[0098]
Example11
  1.4 parts of an azo compound of Exemplified Compound (2-12), 0.7 part of a polyvinyl butyral resin of Exemplified Compound (11-1) (# 6000C manufactured by Denki Kagaku Kogyo Co., Ltd.), and Exemplified Compound (11-3) The phenoxy resin (0.7 part) was dispersed in 44 parts of methyl ethyl ketone and 15 parts of 4-methoxy-4-methylpentanone-2 using a sand grinder mill.
[0099]
  A charge generation layer was provided on the aluminum vapor deposition surface on which the dispersion thus obtained was vapor deposited on a polyester film by a bar coater so that the dry film thickness was 0.4 μm.
  30 parts by weight of the arylamine compound represented by the exemplified compound (1-2), 30 parts by weight of the arylamine compound represented by the exemplified compound (5-2), 100 parts by weight of the polycarbonate resin of the exemplified compound (7-4), and the exemplified compound A charge transfer layer was provided so that a solution obtained by dissolving 10 parts by weight of the electron-withdrawing compound (8-2) in 450 parts by weight of tetrahydrofuran and 100 parts by weight of toluene was dried by a film applicator so that the film thickness after drying was 30 μm. The photoreceptor thus prepared is used as a photoreceptor.11And
  The obtained photoreceptor was evaluated for electric characteristics in the same manner as in Example 1. Further, the same measurement was repeated 1000 times. Table the results4Shown in
[0100]
[Table 14]

[0101]
Example12
  Example3Implementation photoconductor made in3Example using11In the same manner as above, the electrical characteristics were measured 1000 times.
  Table of results together with the first measurement5Shown in
[0102]
[Table 15]

[0103]
Example13
  Except that 10 parts by weight of the electron withdrawing compound of Exemplified Compound (8-2) was used in place of 10 parts by weight, Example 211Conductor in the same manner as12The electrical characteristics were measured. Table the results6Shown in
[0104]
[Table 16]

[0105]
Example14
  Example11A charge generation layer was prepared in the same manner as described above. On top of this, 30 parts by weight of the arylamine compound represented by the exemplified compound (1-2), 30 parts by weight of the arylamine compound represented by the exemplified compound (5-2), and 100 parts by weight of the polycarbonate resin of the exemplified compound (7-4). Charge transfer of a solution obtained by dissolving 10 parts by weight of the phenolic antioxidant of Example Compound (9-1) in 450 parts by weight of tetrahydrofuran and 100 parts by weight of toluene with a film applicator so that the film thickness after drying is 30 μm. A layer was provided. The photoreceptor thus prepared is used as a photoreceptor.13And
  Example11The results of measurements performed in the same way as7Shown in
[0106]
[Table 17]

[0107]
Example15
  Example11A charge generation layer was prepared in the same manner as described above. On top of this, 30 parts by weight of the arylamine compound represented by the exemplified compound (1-2), 30 parts by weight of the arylamine compound represented by the exemplified compound (5-2), and 100 parts by weight of the polycarbonate resin of the exemplified compound (7-4). A solution prepared by dissolving 10 parts by weight of the phenolic antioxidant of the exemplified compound (9-1) and 2 parts of the electron-withdrawing compound of the exemplified compound (8-7) in 450 parts by weight of tetrahydrofuran and 100 parts by weight of toluene The charge transfer layer was provided so that the film thickness after drying by an applicator was 30 μm. The photoreceptor thus prepared is used as a photoreceptor.14And
  Example11The results of measurements performed in the same way as8Shown in
[0108]
[Table 18]

[0109]
Reference example1
  35 parts by weight of the arylamine compound represented by the exemplified compound (1-2), 25 parts by weight of the arylamine compound represented by the exemplified compound (5-2), 100 parts by weight of the polycarbonate resin of the exemplified compound (7-4) (Mitsubishi Gas) Chemical Z-300), tetrahydrofuran 400 parts by weight and toluene 170 parts by weight. The viscosity of this solution was 204 cPs. A coating film having a dry film thickness of 25 microns could be formed by dip coating using an aluminum cylinder having a diameter of 30 mm, a length of 350 mm, and a thickness of 1 mm.
  The solution was allowed to stand at 5 ° C. for 30 days under sealing, but no change in liquidity was observed.
[0110]
Example16
  Example5Except for using the arylamine compound of Exemplified Compound (1-3) instead of the arylamine compound of Exemplified Compound (1-2) used in Example 1, Example5Conductor in the same manner as15Create an example5The electrical characteristics were evaluated in the same manner as described above. Table the results9Shown in
[0111]
Example17
  Example5Except for using the arylamine compound of the exemplified compound (1-7) instead of the arylamine compound of the exemplified compound (1-2) used in Example 1,5Conductor in the same manner as16Create an example5The electrical characteristics were evaluated in the same manner as described above. Table the results9Shown in
[0112]
[Table 19]

[0113]
Reference example2
  Reference example1In Example 1, a solution was prepared in the same manner except that 170 parts by weight of 1,4-dioxane was used instead of 170 parts by weight of toluene. The viscosity of this solution is 316 cPs
Met. An attempt was made to form a coating film with a dry film thickness of 25 microns by dip coating using an aluminum cylinder with a diameter of 30 mm, a length of 350 mm, and a wall thickness of 1 mm in this solution. The gas expanded and overflowed from the cylinder and floated in the solution. Therefore, the obtained coating film was inferior in film thickness uniformity as compared with the case of using toluene.
[0114]
Reference example3
  Reference example1In the above, in place of 35 parts by weight of the arylamine compound represented by the exemplary compound (1-2) and 25 parts by weight of the arylamine compound represented by the exemplary compound (5-2), the compound is represented by the exemplary compound (1-2). Reference example except that 60 parts by weight of arylamine compound was used1A solution was prepared in the same manner as above. The viscosity of this solution was 212 cPs. When this solution was allowed to stand at 5 ° C., precipitation of an arylamine compound was observed in 3 days.
[0115]
Comparative example1~5
  Example5~10In place of 30 parts by weight of the arylamine compound represented by the exemplified compound (1-2) and 30 parts by weight of the arylamine compound represented by the exemplified compound (5-2), 60 parts by weight of the arylamine compound represented by the following structural formula In the examples,5~10In the same manner as above, each comparative photoconductor1~5The electrical characteristics were measured. Table the results10Shown in
[0116]
[Chemical40]

[0117]
[Table 20]

[0118]
【The invention's effect】
  The electrophotographic photosensitive member of the present invention has electrophotographic characteristics excellent in high sensitivity, low residual potential, high durability, etc., is not easily affected by ozone and nitrogen oxides generated from the system, and is repeatedly used. In addition, there is an advantage that the photosensitive member has stable characteristics and image quality and has extremely high durability.
  The photoreceptor of the present invention can be used in a wide range of electrophotographic applications such as analog copying machines, digital copying machines, and printers.
[Brief description of the drawings]
FIG. 1 is an X-ray diffraction spectrum diagram of an oxytitanium phthalocyanine pigment used in the present invention.
FIG. 2 is an X-ray diffraction spectrum diagram of an oxytitanium phthalocyanine pigment used in the present invention.
FIG. 3 is an X-ray diffraction spectrum diagram of an oxytitanium phthalocyanine pigment used in the present invention.

Claims (11)

On a conductive support, a charge transfer layer containing an arylamine compound represented by the following general formulas (1) and (5) and an azo compound represented by the following general formula (2) or (3) A laminated electrophotographic photosensitive member comprising a photosensitive layer having a charge generation layer contained therein.

[In General Formula (1), each of benzene rings A, B, C and D may have an alkyl group or an aryl group as a substituent, and Y represents an alkylene group which may have a substituent. .
In the general formulas (2) and (3), Z represents a tetrazo component residue represented by the following general formula (2-a) or (2-b),

In general formulas (2-a) and (2-b), R ¹ , R ² , R ³ and R ⁴ represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and these may be the same or different from each other. Often, G represents a residue that forms a condensed ring together with a benzene ring, and J represents a hetero atom, a divalent hydrocarbon group, a hetero ring, or a group in which a divalent hydrocarbon group and a hetero ring are linked. However, the group represented by the following general formula (j) is excluded.

(In the formula, R is a hydrogen atom, a substituted or unsubstituted alkyl group or a heterocyclic group, and n is 0 or 1.)
Cp ₁ , Cp ₂ , Cp ₃ , Cp ₄ and Cp ₅ each represent a coupler residue. However, the case where Cp ₁ and Cp ₂ are groups represented by the following general formula (4) is excluded.

(In the general formula (4), R ⁵ Represents an alkyl group, R ⁶ Represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group, an ester group or an acyl group, and the benzene ring K may have a substituent. )

(In the general formula (5), R ⁷ , R ⁸ and R ⁹ are hydrogen atoms or alkyls which may have a substituent.
Represents a kill group. )] 2. The multilayer electrophotographic photosensitive member according to claim 1, wherein the charge generation layer further contains oxytitanium phthalocyanine. The multilayer electrophotographic photosensitive member according to claim 1 or 2, wherein the azo compound represented by the general formula (2) is an azo compound represented by the general formula (2 ').
[Chemical 6]
Cp ₆ -N = N-Z'-N = N-Cp ₇ (2 ')
(In the general formula (2 ′), Z ′ represents the general formula (2-a) or the following structural formula

And Cp ₆ and Cp ₇ each represent a coupler residue. ) The multilayer electrophotographic photosensitive member according to claim 1 or 2, wherein the azo compound is an azo compound represented by the general formula (2 ").

(In the general formula (2 ″), Cp ₈ and Cp ₉ each represent a coupler residue.) Claims 1 to 4 laminated-type electrophotographic photosensitive member according charge transfer layer contains an electron-withdrawing substance. 6. The multilayer electrophotographic photosensitive member according to claim 5 , wherein the electron withdrawing substance is a dicyanovinyl-based electron withdrawing substance. The electrophotographic photosensitive member of a laminated type according to any one of claims 1 to 6 the charge transfer layer contains an antioxidant. The multilayer electrophotographic photosensitive member according to claim 7 , wherein the antioxidant is a hindered phenol-based oxidizing agent. The multilayer electrophotographic photoreceptor according to any one of claims 1 to 8 , wherein the charge transfer layer contains a binder resin containing a repeating unit represented by the following general formula (6).

(In the general formula (6), the benzene rings L and M may have a substituent, and R ¹⁰ and R ¹¹ may have an alkyl group or a substituent which may have a substituent. Represents a good aryl group, and R ¹⁰ and R ¹¹ may be condensed to form an optionally substituted hydrocarbon ring.) The multilayer electrophotographic photoreceptor according to any one of claims 1 to 9 , wherein the charge transfer layer is coated using an aromatic hydrocarbon as a coating solvent. The multilayer electrophotographic photosensitive member according to claim 10 , wherein the aromatic hydrocarbon is benzene which may have a substituent.

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