JP3605776B2 - Electrophotographic photoreceptor - Google Patents

Description

【００１１】
一般式（１）中、Ａ，Ｂは各々独立にＺにより結合され、Ｚは置換または未置換の芳香族炭化水素環、複素環の二価の基を表す。但しＡとＢは同一であっても異なっていてもよい。
【００１２】
一般式（１）中、Ｚの置換または未置換の芳香族炭化水素環、複素環の具体例としては、ベンゼン環、ナフタレン環、フラン環、チオフェン環、ピロール環、ピリジン環などを挙げることができるが、特にはベンゼン環の二価の基が好ましい。またこれらの環にはアルキル基、アルコキシ基、ハロゲン原子、ニトロ基、シアノ基、アルコキシカルボニル基、アミド基等の置換基を有していても良い。
【００１３】
一般式（１）中、Ａ、Ｂが誘導される化合物の好ましい具体例としては一般式（２）〜（４）に示されるようなベンゾキノン、ナフトキノン、シクロペンタジエノン、インデノン、４−オキソチオピラン−１，１−ジオキシド系化合物が挙げられる。
【００１４】
【化６】

【００１５】
一般式（２）中、Ｑ_１は酸素原子または＝Ｃ（Ｒ_１）Ｒ_２または＝Ｎ−ＣＮを表す。
【００１６】
Ａｒ_１は置換、未置換の芳香族炭化水素環基、複素環基を表し、Ａｒ_２は水素原子または置換、未置換の芳香族炭化水素環基、複素環基を表し、またＡｒ_１とＡｒ_２が共同して置換、未置換の芳香族炭化水素環基、複素環基を形成しても良い。
【００１７】
Ｒ_１及びＲ_２は各々独立にシアノ基、アルコキシカルボニル基、アシル基を表す。
【００１８】
【化７】

【００１９】
一般式（３）中、Ｑ_２は酸素原子または＝Ｃ（Ｒ_３）Ｒ_４または＝Ｎ−ＣＮを表す。
【００２０】
Ａｒ_３、Ａｒ_４、Ａｒ_５は置換、未置換の芳香族炭化水素環基、複素環基を表し、またＡｒ_３とＡｒ_４が共同して置換、未置換の芳香族炭化水素環基、複素環基を形成しても良い。
【００２１】
Ｒ_３及びＲ_４は各々独立にシアノ基、アルコキシカルボニル基、アシル基を表す。
【００２２】
【化８】

【００２３】
一般式（４）中、Ｑ_３は酸素原子または＝Ｃ（Ｒ_５）Ｒ_６または＝Ｎ−ＣＮを表す。
【００２４】
Ａｒ_６は置換、未置換の芳香族炭化水素環基、複素環基を表す。
【００２５】
Ｒ_５及びＲ_６は各々独立にシアノ基、アルコキシカルボニル基、アシル基を表す。
【００２６】
Ｑ_１、Ｑ_２、Ｑ_３におけるアルコキシカルボニル基の具体例としては、メトキシカルボニル、エトキシカルボニル、ブトキシカルボニル、オクチルオキシカルボニル基等を挙げることができる。
【００２７】
Ｑ_１、Ｑ_２、Ｑ_３におけるアシル基の具体例としては、アシル、プロピオニル、ベンゾイル基等を挙げることができる。
【００２８】
Ａｒ_１、Ａｒ_２、Ａｒ_３、Ａｒ_４、Ａｒ_５、Ａｒ_６における芳香族炭化水素環、複素環の具体例としてはフェニル、ナフチル、ピリジル、ピロリル、フリル、チエニル基等を挙げることができる。またこれらの各環基にはメチル、エチル、トリフルオロメチル等のアルキル基、メトキシ、エトキシ等のアルコキシ基、フッ素、塩素等のハロゲン原子、ニトロ基、シアノ基、アルコキシカルボニル基、アミド基等の置換基を有していても良い。またＡｒ_１とＡｒ_２及びとＡｒ_３とＡｒ_４とで共同し各々ナフトキノン環、インデノン環等の多環縮合環を形成しても良い。
【００２９】
次に以下の「化９，１０」に、これらＡ，Ｂの好ましい具体例をその還元電位とともに示す。尚、下記ではＡ，Ｂに対しＸ部位対応部をベンゼン環とした化合物で示してある。
【００３０】
【化９】

【００３１】
【化１０】

【００３２】
還元電位は以下に記載する方法により測定した。
【００３３】
試料化合物を０．１Ｍ−（Ｃ_２Ｈ_５）_４Ｎ・ＣｌＯ_４／アセトニトリル溶液に１ｍＭの濃度になるように溶解し、試料溶液とする。そしてこの試料溶液をサイクリックボルタンメトリー法にて高電圧（＋０．５Ｖ）より低電圧（−１．５Ｖ）へ電位を変化させ、得られた電流変化のピーク値（最も高電位側）をもって還元電位とした。
【００３４】
本測定において比較電極としては銀／銀イオン（Ａｇ／Ａｇ＋）電極を用い、作用極として白金極を使用した。
【００３５】
本発明の電子輸送性物質を含む感光層を有する電子写真感光体では高感度でかつ低い残留電位が達成できる。また、特には本発明のこれらアクセプター分子Ａ，Ｂの二量体化合物「Ａ−Ｚ−Ｂ」を電子写真感光体の電子輸送性物質として用いる場合にはアクセプター分子単体と比較して電位の安定性に優れ、特に感光体を繰り返し使用したときの残留電位の増加が低いことが効果に挙げられる。
【００３６】
本発明の電子輸送性物質は公知の方法により合成することができる。
【００３７】
（合成例１）
１，１″−（１′，４′−フェニレン）ビス（３，３″−フェニル−２，５，２″５″−シクロヘキサジエン−１，４，１″４″−ジオン）（４．４２ｇ；０．０１モル）とシアノ酢酸ブチル（４．２３ｇ；０．０３モル）を脱水テトラヒドロフラン１６０ｍｌに溶解する。窒素気流中下、撹拌しながら四塩化チタン／四塩化炭素溶液（９ｍｌ／２０ｍｌ）を０〜１０℃にて滴下する。滴下後、同温度にて３０分撹拌する。次にピリジン（１０ｍｌ）を同温度にて滴下し、更に室温下３時間撹拌反応させる。
【００３８】
反応後、反応液を純水５００ｍｌに注ぎ、トルエン８００ｍｌにて抽出する。トルエン層を１０％塩酸水溶液４００ｍｌにて洗浄し、更に純水４００ｍｌにて２回洗浄する。洗浄後、無水硫酸マグネシウムにてトルエン層を乾燥した。乾燥後、トルエンを除去して、残った残査をシリカゲルカラムにて分離し、再結晶を行って目的物である例示化合物Ｎｏ．３（４．５ｇ；ｙ．６５％）を得る。
【００３９】
（合成例２）
１，１″−（１′，４′−フェニレン）ビス（３，３″−フェニル−２，５，２″５″−シクロヘキサジエン−１，４，１″４″−ジオン）（４．４２ｇ；０．０１モル）ジクロロメタン１２０ｍｌに溶解する。窒素気流中下、撹拌しながら四塩化チタン／ジクロロメタン溶液（５．７ｇ／２０ｍｌ）を０〜１０℃にて滴下する。滴下後、同温度にて３０分撹拌する。次にビス（トリメチルシリル）カルボジイミド（５．５８ｇ）を同温度にて滴下し、更に室温下６時間撹拌した後、そのまま一晩放置する。
【００４０】
反応後、反応液を純水５００ｍｌに注ぎ、ジクロロメタン８００ｍｌにて抽出する。ジクロロメタン層を純水４００ｍｌにて２回洗浄する。洗浄後、無水硫酸マグネシウムにてジクロロメタン層を乾燥した。乾燥後、ジクロロメタンを除去して、残査をシリカゲルカラムにて分離し、再結晶を行って目的物である例示化合物Ｎｏ．５６（２．８９ｇ；ｙ．５９％）を得る。
【００４１】
次に、本発明の電子輸送性物質の具体例について述べるがこれによって本発明の電子輸送性物質が限定されるものではない。
【００４２】
【化１１】

【００４３】
【化１２】

【００４４】
【化１３】

【００４５】
【化１４】

【００４６】
【化１５】

【００４７】
【化１６】

【００４８】
【化１７】

【００４９】
【化１８】

【００５０】
【化１９】

【００５１】
【化２０】

【００５２】
【化２１】

【００５３】
【化２２】

【００５４】
【化２３】

【００５５】
【化２４】

【００５６】
【化２５】

【００５７】
【化２６】

【００５８】
【化２７】

【００５９】
【化２８】

【００６０】
【化２９】

【００６１】
【化３０】

【００６２】
【化３１】

【００６３】
【作用】
本発明の前記物質は優れた電子輸送性を有し、これをバインダー中に分子分散した感光層を導電性支持体上に設けることにより本発明の電子写真感光体を製造することができる。本発明の電子輸送性物質はその優れた電子輸送能を利用して、これを電荷輸送物質として用い、これと組み合わせて有効に作用し得る電荷発生物質を共に用いることにより、いわゆる機能分離型の感光体とすることができる。前記機能分離型感光体は前記両物質の混合分散単層構成の感光体であってもよいが、電荷発生層を下層とし、本発明の電子輸送性物質からなる電荷輸送層を上層とする積層型感光体とすることがより好ましい。何れの層構成においても、導電性支持体と感光層の間にバリア機能と接着性を持つ下引層（中間層）を設けても良く、感光層の上に保護層を設けても良い。
【００６４】
電荷輸送層は本発明の電子輸送性物質を適当な溶媒に単独で或いはバインダ樹脂と共に溶解分散せしめたものをアプリケーター、バーコーター、ディップコーター等を用いて塗布、乾燥して形成することができる。
【００６５】
電荷輸送層に使用可能なバインダー樹脂としては、例えばポリスチレン、アクリル樹脂、メタクリル樹脂、塩化ビニル樹脂、酢酸ビニル樹脂、ポリビニルブチラール樹脂、エポキシ樹脂、ポリウレタン樹脂、フェノール樹脂、ポリエステル樹脂、アルキッド樹脂、ポリカーボネート樹脂、シリコン樹脂、メラミン樹脂ならびに、これらの樹脂の繰り返し単位のうちの２つ以上を含む共重合体樹脂、又これらの絶縁性樹脂の他、ポリ−Ｎ−ビニルカルバゾール等の高分子有機半導体が挙げられる。電子輸送性物質の分散媒としては、例えばトルエン、キシレン等の炭化水素類；メチレンクロライド、１，２−ジクロルエタン等のハロゲン化炭化水素；メチルエチルケトン、シクロヘキサノン等のケトン類；酢酸エチル、酢酸ブチル等のエステル類；メタノール、エタノール、プロパノール、ブタノール、メチルセルソルブ、エチルセルソルブ等のアルコール類及びこの誘導体；テトラヒドロフラン、１，４−ジオキサン等のエーテル類；ピリジンやジエチルアミン等のアミン類；Ｎ，Ｎ−ジメチルホルムアミド等のアミド類等の窒素化合物；その他脂肪酸及びフェノール類；二硫化炭素や燐酸トリエチル等の硫黄、燐化合物等の１種又は２種以上を用いることができる。
【００６６】
電荷輸送層中のバインダ樹脂１００重量部当り電子輸送性物質は２０〜２００重量部が好ましく、特に好ましくは５０〜１５０重量部である。形成される電荷輸送層の膜厚は、好ましくは５〜３０μｍである。又単層機能分離型の電子写真感光体の場合のバインダ：電子輸送性物質：電荷発生物質の割合は１〜１００：１〜５００：１〜５００が好ましく、形成される感光層の膜厚は５〜５０μｍである。
【００６７】
次に電荷発生層は電荷発生物質を適当な溶媒に単独で或いは上述の電荷輸送層に用いたものと同様なバインダ樹脂と共に分散せしめた分散液をディップ塗布、スプレイ塗布、ブレード塗布、ロール塗布等によって支持体又は下引層上に塗布して乾燥させる方法により設けるもの、又は電荷発生物質を支持体又は下引層上に蒸着したものが用いられる。分散塗布の場合、用いられる溶媒としても前記電子輸送性物質の分子分散において用いた分散媒を用いることができる。分散にはボールミル、ホモミキサ、サンドミル、超音波分散機、アトライタ等が用いられる。
【００６８】
用いられる電荷発生物質としては公知のどのようなものでの使用もできるが、例えばセレン系の無機半導体、種々のフタロシアニン化合物、アゾ化合物、ピリリウム化合物、ペリレン系化合物、シアニン系化合物、スクアリウム化合物、多環キノン化合物が使用できる。
【００６９】
本発明の感光体が積層型構成の場合、電荷発生層中のバインダ：電荷発生物質の重量比は０〜１０：１〜５０である。以上のようにして形成される電荷発生層の膜厚は、好ましくは０．０１〜１０μｍ、特に好ましくは０．１〜５μｍである。
【００７０】
次に前記感光層を支持する導電性支持体としては、アルミニウム、ニッケルなどの金属板・金属ドラム、又はアルミニウム、酸化錫、酸化インジュウムなどを蒸着したプラスチックフィルム、又は導電性物質を塗布した紙・プラスチックフィルム・ドラムを使用することができる。
【００７１】
又本発明の感光層においては、オゾン劣化防止の目的で以下に示すような酸化防止剤を添加することができる。
【００７２】
（１）ヒンダードフェノール類
（２）ヒンダードアミン類
（３）パラフェニレンジアミン類
（４）ハイドロキノン類
（５）有機燐化合物類
これらの化合物はゴム、プラスチック、油脂類等の酸化防止剤として知られており、市販品を容易に入手できる。
【００７３】
又本発明の感光体には、その他、必要により感光層を保護する目的で紫外線吸収剤又は感色性補正の染料を含有してもよい。
【００７４】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されない。尚、本文中「部」とは「重量部」を表す。
【００７５】
実施例１〜２５
アルミニウムを蒸着したＰＥＴフィルム上にポリアミド樹脂「ＣＭ８０００」（東レ社製）からなる厚さ０．５μｍの中間層を設けた。その上に、Ｘ線回折におけるブラッグ角２θの９．５°、２４．１°、２７．２°にピークを有するチタニルフタロシアニン１部、シリコーン−ブチラール樹脂０．５部、分散媒として酢酸ｔ−ブチル／メトキシメチルペンタノン＝９／１ ５０部をサンドグラインダーを用いて分散した液をワイヤーバーを用いて塗布し膜厚０．３μｍの電荷発生層を形成した。次いで表１に示す例示化合物１部とポリカーボネート樹脂「ユーピロンＺ−２００」（三菱瓦斯化学社製）１．５部をＴＨＦ（テトラヒドロフラン）１０部に溶解し、電荷発生層上にドクターブレードを用いて塗布し膜厚２０μｍの電荷輸送層を形成し、実施例感光体１〜２５を作製した。
【００７６】
比較例１
実施例１の例示化合物Ｎｏ．３を後記化合物Ｎ−１に変えた他は実施例１と同様にして比較例感光体１を作製した。
【００７７】
比較例２
実施例１の例示化合物Ｎｏ．３を後記化合物Ｎ−２に変えた他は実施例１との同様にして比較例感光体２を作製した。
【００７８】
【化３２】

【００７９】
【表１】

【００８０】
比較例３
実施例１の例示化合物Ｎｏ．３を後記化合物Ｎ−３に変えた他は実施例１と同様にして比較例感光体３を作製した。
【００８１】
比較例４
実施例１の例示化合物Ｎｏ．３を後記化合物Ｎ−４に変えた他は実施例１と同様にして比較例感光体４を作製した。
【００８２】
比較例５
実施例１の例示化合物Ｎｏ．３を後記化合物Ｎ−５に変えた他は実施例１と同様にして比較例感光体５を作製した。
【００８３】
評価１
実施例１〜２５及び比較例１〜５により得られた電子写真感光体サンプルについて静電複写試験装置ＥＰＡ−８１００（川口電機社製）を用いて＋６ｋＶにて５秒間帯電させ、その後暗所にて５秒放置した時の帯電電位Ｖａを測定した。次に１０ｌｕｘの白色光を露光し、表面電位が半分になるまでの露光量Ｅ１／２（ｌｕｘ．ｓｅｃ）を求めて感度とした。又１０秒露光した後の残留電位Ｖｒを求めた。結果を表２に示す。
【００８４】
さらに上記の条件に前露光５００ｌｕｘ、２秒を加え、前露光・帯電・暗所放置・露光のプロセスを繰り返して、３００回後の残留電位の変位量ΔＶｒを求めた。結果を表２に示す。
【００８５】
【表２】

【００８６】
上記表に示すように、本発明の化合物は何れも優れた感度、低い残留電位を示す。これに対して比較例では低感度で残留電位が高い、若しくは初期の感度、残留電位は低いものの繰り返しでの残留電位上昇が大きくなってしまう。
【００８７】
実施例２６
Ｘ型無金属フタロシアニン１部、ポリカーボネート樹脂「ユーピロンＺ−２００」（三菱瓦斯化学社製）０．５部、分散媒としてテトラヒドロフラン１０部をサンドグラインダーを用いて分散した液に、フタロシアニン成分が５部、例示化合物Ｎｏ．３が３０部、後記化学式（Ｐ−１）の正孔輸送物質が３０部、ポリカーボネート樹脂が６０部になるように例示化合物、正孔輸送物質、ポリカーボネート樹脂を溶解したＴＨＦ溶液（ポリマー濃度１５ｗ／ｖ％）を加えて感光層液を調製した。
【００８８】
【化３３】

【００８９】
アルミニウムを蒸着したＰＥＴフィルム又は円筒形アルミ基体上にポリアミド樹脂「ＣＭ８０００」（東レ社製）からなる厚さ０．５μｍの中間層を設け、その上に本感光層液を塗布して膜厚２０μｍの感光層を形成し、実施例２６の単層感光体を作製した。
【００９０】
実施例２７
実施例２６における例示化合物Ｎｏ．３をＮｏ．６に代えた他は、実施例２６と同様にして実施例感光体２７を作製した。
【００９１】
評価２
実施例２６及び２７により得られた電子写真感光体について、評価１と同様にして感度Ｅ１／２及び残留電位Ｖｒを求めた。その結果を表３に示す。
【００９２】
【表３】

【００９３】
以上のように、本発明の電子輸送性物質を用いた電子写真感光体は、従来の電荷輸送物質を用いた電子写真感光体と比較して、感度が高く、繰り返し使用時の感光体特性も安定していることがわかる。
【００９４】
【発明の効果】
本発明により、電子輸送能を有する電荷輸送物質を用いて高感度でかつ残留電位が小さく、更に繰り返し使用してもそれらの特性が変化しない耐久性の優れた電子写真感光体を提供することが出来る。[0001]
[Industrial applications]
The present invention relates to an electrophotographic photosensitive member for forming an electrostatic latent image. More specifically, the present invention relates to an electrophotographic photoreceptor having a layer containing a compound having an electron transporting ability.
[0002]
[Prior art]
Conventionally, as an electrophotographic photosensitive member, an inorganic photosensitive member having a photosensitive layer mainly composed of an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, and silicon has been widely used. However, these are not always satisfactory in sensitivity, thermal stability, moisture resistance, durability in repeated use, and the like. Inorganic photoreceptors have many substances harmful to the human body, and have a problem in disposal.
[0003]
In order to overcome the disadvantages of these inorganic photoconductors, research and development of organic photoconductors containing an organic photoconductive compound as a main component have been actively conducted in recent years. In particular, a function-separated type photoreceptor in which a carrier generation function and a carrier transport function are respectively assigned to different substances, a material can be selected from a wide range, and a photoreceptor having any performance can be relatively easily produced. Therefore, much research has been done. Many of these are in practical use. For example, US Pat. No. 3,871,882 uses a perylene derivative as a carrier generating layer and an oxadiazole derivative as a carrier transporting layer, and JP-A-55-84943 discloses a distyrylbenzene-based bisazo compound as a carrier generating substance, A substance using a hydrazone compound as a substance is known.
[0004]
As such substances having a carrier transporting function, compounds such as pyrazoline, hydrazone, and triphenylamine derivatives are known, and all of them are substances having a hole transporting ability and include a layer containing a carrier generating substance. In the case of a function-separated type photoreceptor having a lower layer as a lower layer and a layer containing a carrier transporting material as an upper layer, it is necessary to adopt a method of negatively charging the surface of the photoreceptor. For this reason, it is not possible to use a developer which has been widely used in the past and which is used for an inorganic photoreceptor having excellent positive chargeability. Further, there is a disadvantage that the amount of ozone generated when the photoconductor is charged is larger than that in the case of positive charging performed with the inorganic photoconductor. In particular, the large amount of ozone generated is a problem not only in the deterioration of the photoreceptor due to the generation of ozone, but also in the effect on the human body and the environment.
[0005]
As a positively charged photoreceptor using an organic photoreceptor, a photoreceptor having a reverse layer configuration in which a carrier generating layer is used as an upper layer and a carrier transporting layer is used as a lower layer using a conventional hole transporting material, a carrier generating material and a carrier transporting material And a single layer photoreceptor containing the same in the same layer have been studied. However, there has not been obtained one having sufficient performance in terms of durability, environmental characteristics, and the like, which can cope with high-speed machines.
[0006]
In order to solve the above problems, it is required to apply a substance having an electron transporting ability to the carrier transporting layer as a carrier transporting substance. As such an electron-transporting substance, 2,4,7-trinitrofluorenone is known, but this substance has poor solubility and compatibility with a solvent and a polymer used as a binder. They do not have sufficient characteristics when constructed. Its use has been discontinued due to its carcinogenicity.
[0007]
In addition, recently, some electron transporting substances in which a soluble group is introduced into an electron accepting structure have been proposed. For example, JP-A-1-206349, JP-A-2-135362, JP-A-2-214866, JP-A-3-290666, and “Japan Hard Copy '92”, P173 (1992). However, at present, any compound has insufficient sensitivity and potential characteristics in combination with an existing carrier-generating substance, and presents practical problems.
[0008]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a high-sensitivity and small residual potential by using a charge transporting substance having an electron transporting ability, and furthermore, an electrophotography having excellent durability in which their properties do not change even when repeatedly used. It is to provide a photoreceptor.
[0009]
[Means for Solving the Problems]
The present inventors have made intensive studies to achieve the above object, and as a result, have completed the present invention. That is, an object of the present invention is to provide an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support , wherein the photosensitive layer contains a compound represented by the general formula (1), and A and B are represented by the following general formula (2) ), (3) or (4) .
[0010]
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[0011]
In the general formula (1), A and B are each independently bonded by Z, and Z represents a substituted or unsubstituted aromatic hydrocarbon ring or heterocyclic divalent group. However, A and B may be the same or different.
[0012]
In the general formula (1), specific examples of the substituted or unsubstituted aromatic hydrocarbon ring and hetero ring of Z include a benzene ring, a naphthalene ring, a furan ring, a thiophene ring, a pyrrole ring, and a pyridine ring. Although a divalent group having a benzene ring is particularly preferable. Further, these rings may have a substituent such as an alkyl group, an alkoxy group, a halogen atom, a nitro group, a cyano group, an alkoxycarbonyl group, and an amide group.
[0013]
In the general formula (1), preferred examples of the compound from which A and B are derived include benzoquinone, naphthoquinone, cyclopentadienone, indenone, and 4-oxothiopyran as shown in general formulas (2) to (4). 1,1-dioxide compound is Ru mentioned.
[0014]
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[0015]
In the general formula (2), Q ₁ represents an oxygen atom or ＣC (R ₁ ) R ₂ or ＮN—CN.
[0016]
Ar ₁ represents a substituted, unsubstituted aromatic hydrocarbon ring group, a heterocyclic group, Ar ₂ represents a hydrogen atom or a substituted, unsubstituted aromatic hydrocarbon ring group, a heterocyclic group, and Ar ₁ and Ar ₂ may form a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group together.
[0017]
R ₁ and R ₂ each independently represent a cyano group, an alkoxycarbonyl group, or an acyl group.
[0018]
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[0019]
In the general formula (3), _{Q 2} represents an oxygen atom or = _{C (R} 3) R ₄ or = N-CN.
[0020]
Ar ₃ , Ar ₄ , and Ar ₅ represent a substituted or unsubstituted aromatic hydrocarbon ring group or a heterocyclic group, and Ar ₃ and Ar ₄ cooperate to form a substituted or unsubstituted aromatic hydrocarbon ring group or a heterocyclic group. A ring group may be formed.
[0021]
R ₃ and R ₄ each independently represent a cyano group, an alkoxycarbonyl group, or an acyl group.
[0022]
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[0023]
In the general formula (4), _{Q 3} represents an oxygen atom or = _{C (R} 5) R ₆ or = N-CN.
[0024]
Ar ₆ represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group.
[0025]
R ₅ and R ₆ each independently represent a cyano group, an alkoxycarbonyl group, or an acyl group.
[0026]
Specific examples of the alkoxycarbonyl group in Q ₁ , Q ₂ and Q ₃ include a methoxycarbonyl, ethoxycarbonyl, butoxycarbonyl, octyloxycarbonyl group and the like.
[0027]
Specific examples of the acyl group in Q ₁ , Q ₂ and Q ₃ include acyl, propionyl, benzoyl and the like.
[0028]
Specific examples of the aromatic hydrocarbon ring and the heterocyclic ring in Ar ₁ , Ar ₂ , Ar ₃ , Ar ₄ , Ar ₅ , and Ar ₆ include phenyl, naphthyl, pyridyl, pyrrolyl, furyl, and thienyl groups. In addition, each of these ring groups includes an alkyl group such as methyl, ethyl and trifluoromethyl, an alkoxy group such as methoxy and ethoxy, a halogen atom such as fluorine and chlorine, a nitro group, a cyano group, an alkoxycarbonyl group and an amide group. It may have a substituent. Ar ₁ and Ar ₂ and Ar ₃ and Ar ₄ may be combined to form a polycyclic fused ring such as a naphthoquinone ring and an indenone ring.
[0029]
Then the "Formula 9" below, shows these A, a preferred embodiment of B with its reduction potential. In the following, a compound having a benzene ring in the X site corresponding to A and B is shown.
[0030]
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[0031]
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[0032]
The reduction potential was measured by the method described below.
[0033]
The test compound 0.1M- _{(C 2} H ₅₎ in ₄ N · ClO 4 / acetonitrile solution was dissolved to a concentration of 1 mM, and the sample solution. The potential of this sample solution is changed from a high voltage (+0.5 V) to a low voltage (−1.5 V) by cyclic voltammetry, and the peak value of the obtained current change (the highest potential side) is used as the reduction potential. And
[0034]
In this measurement, a silver / silver ion (Ag / Ag +) electrode was used as a comparative electrode, and a platinum electrode was used as a working electrode.
[0035]
The electrophotographic photoreceptor having the photosensitive layer containing the electron transporting substance of the present invention can achieve high sensitivity and low residual potential. Particularly, when the dimer compound "AZB" of the acceptor molecules A and B of the present invention is used as an electron transporting substance of an electrophotographic photoreceptor, the potential stability is higher than that of the acceptor molecule alone. The effect is particularly excellent in that the residual potential is low when the photoreceptor is repeatedly used.
[0036]
The electron transporting substance of the present invention can be synthesized by a known method.
[0037]
(Synthesis example 1)
1,1 "-(1 ', 4'-phenylene) bis (3,3" -phenyl-2,5,2 "5" -cyclohexadiene-1,4,1 "4" -dione) (4.42 g) ; 0.01 mol) and butyl cyanoacetate (4.23 g; 0.03 mol) are dissolved in 160 ml of dehydrated tetrahydrofuran. Under a nitrogen stream, a titanium tetrachloride / carbon tetrachloride solution (9 ml / 20 ml) is added dropwise at 0 to 10 ° C. with stirring. After dropping, the mixture is stirred at the same temperature for 30 minutes. Next, pyridine (10 ml) is added dropwise at the same temperature, and the mixture is further stirred and reacted at room temperature for 3 hours.
[0038]
After the reaction, the reaction solution is poured into 500 ml of pure water and extracted with 800 ml of toluene. The toluene layer is washed with a 10% aqueous hydrochloric acid solution (400 ml) and further twice with pure water (400 ml). After washing, the toluene layer was dried with anhydrous magnesium sulfate. After drying, the toluene was removed, the remaining residue was separated by a silica gel column, and recrystallized to give Exemplified Compound No. 3 (4.5 g; y. 65%).
[0039]
(Synthesis example 2)
1,1 "-(1 ', 4'-phenylene) bis (3,3" -phenyl-2,5,2 "5" -cyclohexadiene-1,4,1 "4" -dione) (4.42 g) Dissolved in 120 ml of dichloromethane. Under a nitrogen stream, a titanium tetrachloride / dichloromethane solution (5.7 g / 20 ml) is added dropwise at 0 to 10 ° C. while stirring. After dropping, the mixture is stirred at the same temperature for 30 minutes. Next, bis (trimethylsilyl) carbodiimide (5.58 g) is added dropwise at the same temperature, and the mixture is further stirred at room temperature for 6 hours, and then left as it is overnight.
[0040]
After the reaction, the reaction solution is poured into 500 ml of pure water and extracted with 800 ml of dichloromethane. The dichloromethane layer is washed twice with 400 ml of pure water. After washing, the dichloromethane layer was dried with anhydrous magnesium sulfate. After drying, dichloromethane was removed, the residue was separated with a silica gel column, and recrystallized to give Exemplified Compound No. 56 (2.89 g; y. 59%) are obtained.
[0041]
Next, specific examples of the electron transporting substance of the present invention will be described, but the electron transporting substance of the present invention is not limited thereto.
[0042]
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[0043]
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[0044]
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[0045]
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[0046]
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[0047]
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[0048]
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[0049]
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[0050]
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[0051]
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[0052]
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[0053]
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[0054]
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[0055]
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[0056]
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[0057]
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[0058]
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[0059]
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[0060]
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[0061]
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[0062]
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[0063]
[Action]
The substance of the present invention has an excellent electron transporting property, and the electrophotographic photoreceptor of the present invention can be produced by providing a photosensitive layer in which the molecule is dispersed in a binder on a conductive support. The electron-transporting substance of the present invention utilizes its excellent electron-transporting ability, uses it as a charge-transporting substance, and uses a charge-generating substance that can work effectively in combination with this to form a so-called function-separated type. It can be a photoreceptor. The function-separated type photoreceptor may be a photoreceptor having a single layer structure in which the two substances are mixed and dispersed, but the charge generation layer is a lower layer, and the charge transport layer made of the electron transporting substance of the present invention is an upper layer. It is more preferable to use a photoreceptor. In any of the layer configurations, an undercoat layer (intermediate layer) having a barrier function and adhesiveness may be provided between the conductive support and the photosensitive layer, and a protective layer may be provided on the photosensitive layer.
[0064]
The charge transporting layer can be formed by applying and drying an electron transporting substance of the present invention alone or in a suitable solvent dissolved or dispersed together with a binder resin using an applicator, bar coater, dip coater or the like.
[0065]
Examples of the binder resin usable for the charge transport layer include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate resin. , A silicone resin, a melamine resin, a copolymer resin containing two or more of the repeating units of these resins, and a polymer organic semiconductor such as poly-N-vinylcarbazole in addition to these insulating resins. Can be Examples of the dispersion medium of the electron transporting substance include hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and 1,2-dichloroethane; ketones such as methyl ethyl ketone and cyclohexanone; Esters; alcohols such as methanol, ethanol, propanol, butanol, methylcellosolve and ethylcellosolve and derivatives thereof; ethers such as tetrahydrofuran and 1,4-dioxane; amines such as pyridine and diethylamine; Nitrogen compounds such as amides such as dimethylformamide; other fatty acids and phenols; and one or more of sulfur and phosphorus compounds such as carbon disulfide and triethyl phosphate can be used.
[0066]
The amount of the electron transporting substance is preferably 20 to 200 parts by weight, particularly preferably 50 to 150 parts by weight, per 100 parts by weight of the binder resin in the charge transporting layer. The thickness of the formed charge transport layer is preferably 5 to 30 μm. In the case of a single-layer function-separated electrophotographic photoreceptor, the ratio of binder: electron transporting substance: charge generating substance is preferably from 1 to 100: 1 to 500: 1 to 500, and the thickness of the formed photosensitive layer is 5 to 50 μm.
[0067]
Next, the charge generation layer is formed by dip coating, spray coating, blade coating, roll coating, etc. of a dispersion obtained by dispersing the charge generating substance alone or in a suitable solvent together with a binder resin similar to that used in the above-described charge transport layer. Provided by a method of coating and drying on a support or an undercoat layer, or a charge generation substance deposited on a support or an undercoat layer. In the case of dispersion coating, the solvent used in the molecular dispersion of the electron transporting substance can also be used as the solvent used. For dispersion, a ball mill, a homomixer, a sand mill, an ultrasonic disperser, an attritor, or the like is used.
[0068]
As the charge generation substance to be used, any known charge generation substance can be used. Ring quinone compounds can be used.
[0069]
When the photoreceptor of the present invention has a laminated structure, the weight ratio of the binder to the charge generating substance in the charge generating layer is from 0 to 10: 1 to 50. The thickness of the charge generation layer formed as described above is preferably 0.01 to 10 μm, and particularly preferably 0.1 to 5 μm.
[0070]
Next, as the conductive support for supporting the photosensitive layer, a metal plate or metal drum of aluminum, nickel, or the like, or a plastic film on which aluminum, tin oxide, indium oxide, or the like is deposited, or paper coated with a conductive substance. Plastic film drums can be used.
[0071]
In the photosensitive layer of the present invention, the following antioxidants can be added for the purpose of preventing ozone deterioration.
[0072]
(1) Hindered phenols (2) Hindered amines (3) Paraphenylenediamines (4) Hydroquinones (5) Organophosphorus compounds These compounds are known as antioxidants for rubbers, plastics, oils and the like. And commercially available products are readily available.
[0073]
The photoreceptor of the present invention may further contain, if necessary, an ultraviolet absorber or a dye for correcting color sensitivity for the purpose of protecting the photosensitive layer.
[0074]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the text, “parts” means “parts by weight”.
[0075]
Examples 1 to 25
A 0.5 μm thick intermediate layer made of a polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) was provided on a PET film on which aluminum was deposited. On top of that, 1 part of titanyl phthalocyanine having peaks at 9.5 °, 24.1 ° and 27.2 ° of Bragg angle 2θ in X-ray diffraction, 1 part of silicone-butyral resin, and t-acetic acid as a dispersion medium A liquid in which 150 parts of butyl / methoxymethylpentanone = 9/150 was dispersed by using a sand grinder was applied using a wire bar to form a charge generating layer having a thickness of 0.3 μm. Next, 1 part of the exemplified compound shown in Table 1 and 1.5 parts of a polycarbonate resin "Iupilon Z-200" (manufactured by Mitsubishi Gas Chemical Company) were dissolved in 10 parts of THF (tetrahydrofuran), and the mixture was dissolved on a charge generating layer using a doctor blade. Coating was performed to form a charge transporting layer having a thickness of 20 μm.
[0076]
Comparative Example 1
The exemplified compound No. of Example 1 was used. Comparative Example Photoconductor 1 was prepared in the same manner as in Example 1, except that Compound 3 was changed to Compound N-1.
[0077]
Comparative Example 2
The exemplified compound No. of Example 1 was used. Comparative Example Photoconductor 2 was prepared in the same manner as in Example 1, except that Compound 3 was changed to Compound N-2.
[0078]
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[0079]
[Table 1]

[0080]
Comparative Example 3
The exemplified compound No. of Example 1 was used. Comparative Example Photoconductor 3 was prepared in the same manner as in Example 1, except that Compound 3 was changed to Compound N-3 described later.
[0081]
Comparative Example 4
The exemplified compound No. of Example 1 was used. Comparative Photoconductor 4 was prepared in the same manner as in Example 1 except that Compound 3 was changed to Compound N-4 described later.
[0082]
Comparative Example 5
The exemplified compound No. of Example 1 was used. Comparative Example Photoconductor 5 was prepared in the same manner as in Example 1 except that Compound 3 was changed to Compound N-5 described later.
[0083]
Evaluation 1
The electrophotographic photosensitive member samples obtained in Examples 1 to 25 and Comparative Examples 1 to 5 were charged at +6 kV for 5 seconds using an electrostatic copying tester EPA-8100 (manufactured by Kawaguchi Electric Co., Ltd.), and then charged in a dark place. The charging potential Va when left for 5 seconds was measured. Next, 10 lux of white light was exposed, and an exposure amount E1 / 2 (lux.sec) until the surface potential was reduced to half was determined as the sensitivity. Further, the residual potential Vr after exposure for 10 seconds was determined. Table 2 shows the results.
[0084]
Furthermore, pre-exposure 500 lux and 2 seconds were added to the above conditions, and the processes of pre-exposure, charging, leaving in a dark place, and exposure were repeated, and the displacement amount ΔVr of the residual potential after 300 times was obtained. Table 2 shows the results.
[0085]
[Table 2]

[0086]
As shown in the above table, all the compounds of the present invention show excellent sensitivity and low residual potential. On the other hand, in the comparative example, the residual potential is high at a low sensitivity, or the initial sensitivity and the residual potential are low, but the residual potential rises repeatedly.
[0087]
Example 26
X-type metal-free phthalocyanine (1 part), polycarbonate resin "Iupilon Z-200" (manufactured by Mitsubishi Gas Chemical Company) (0.5 parts), and tetrahydrofuran (10 parts) as a dispersion medium dispersed in a sand grinder using a sand grinder containing 5 parts of a phthalocyanine component. , Exemplified Compound No. No. 3 was 30 parts, a hole transporting substance of the following chemical formula (P-1) was 30 parts, and a polycarbonate resin was dissolved in a THF solution (polymer concentration 15 w / v%) to prepare a photosensitive layer solution.
[0088]
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[0089]
A 0.5 μm thick intermediate layer made of a polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) is provided on a PET film or a cylindrical aluminum substrate on which aluminum is vapor-deposited. Was formed, and a single-layer photoreceptor of Example 26 was produced.
[0090]
Example 27
Exemplified compound No. in Example 26 was used. No. 3 for No. 3. A photosensitive member 27 of Example was produced in the same manner as in Example 26, except for changing the composition to 6.
[0091]
Evaluation 2
For the electrophotographic photosensitive members obtained in Examples 26 and 27, the sensitivity E1 / 2 and the residual potential Vr were determined in the same manner as in Evaluation 1. Table 3 shows the results.
[0092]
[Table 3]

[0093]
As described above, the electrophotographic photoreceptor using the electron transporting material of the present invention has higher sensitivity and the photoreceptor characteristics when repeatedly used as compared with the electrophotographic photoreceptor using the conventional charge transporting material. It turns out that it is stable.
[0094]
【The invention's effect】
According to the present invention, it is possible to provide an electrophotographic photoreceptor that has high sensitivity and a small residual potential by using a charge transporting substance having an electron transporting ability, and has excellent durability in which those properties do not change even when repeatedly used. I can do it.

Claims (5)

On a conductive support an electrophotographic photosensitive member having a photosensitive layer contains a compound represented by the general formula (1) in the photosensitive layer, A, B is a Rukoto represented by the following general formula (2) An electrophotographic photosensitive member characterized by the following.

(In the general formula (1), A and B are each bonded by Z, and Z represents a substituted or unsubstituted aromatic hydrocarbon ring or a heterocyclic divalent group.
In the general formula (2), Q ₁ represents an oxygen atom or = C (R ₁ ) R ₂ or = N-CN.
Ar ₁ represents a substituted, unsubstituted aromatic hydrocarbon ring group, a heterocyclic group, Ar ₂ represents a hydrogen atom or a substituted, unsubstituted aromatic hydrocarbon ring group, a heterocyclic group, and Ar ₁ and Ar ₂ may form a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group together.
R ₁ and R ₂ each independently represent a cyano group, an alkoxycarbonyl group, or an acyl group. ) In an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support, the photosensitive layer contains a compound represented by the general formula (1), and A and B are represented by the following general formula (3). An electrophotographic photosensitive member characterized by the following .

(In the general formula (1), A and B are each bonded by Z, and Z represents a substituted or unsubstituted aromatic hydrocarbon ring or a heterocyclic divalent group.
In the general formula (3), Q ₂ represents an oxygen atom or = C (R ₃₎ R ₄ or = N-CN. Ar ₃ , Ar ₄ and Ar ₅ represent a substituted or unsubstituted aromatic hydrocarbon ring group or a heterocyclic group, and Ar ₃ and Ar ₄ are substituted and unsubstituted aromatic hydrocarbon ring groups or heterocyclic groups. A ring group may be formed.
R ₃ and R ₄ each independently represent a cyano group, an alkoxycarbonyl group, or an acyl group. ) In an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support, the photosensitive layer contains a compound represented by the general formula (1), and A and B are represented by the following general formula (4). An electrophotographic photosensitive member characterized by the following .

(In the general formula (1), A and B are each bonded by Z, and Z represents a substituted or unsubstituted aromatic hydrocarbon ring or a heterocyclic divalent group.
In the general formula (4), Q ₃ represents an oxygen atom or = C (R ₅₎ R ₆ or = N-CN. Ar ₆ represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group.
R ₅ and R ₆ each independently represent a cyano group, an alkoxycarbonyl group, or an acyl group. ) An electrophotographic photosensitive member, wherein the photosensitive layer contains a charge generating material and at least one of the compounds described in any of claims 1 to 3 as a charge transporting material . A charge generation layer containing a charge generation substance on a conductive support, and a charge transport layer containing at least one of the compounds described in any of claims 1 to 3 as a charge transport substance are laminated in the above order. An electrophotographic photoreceptor characterized in that: