JP2005024871A - New quinone compound, electrophotographic photoreceptor and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound useful for an electrophotographic photoreceptor and excellent in electron transport performance, to provide a positive electrification type electrophotographic photoreceptor for a copying machine and a printer having high sensitivity, and to provide an electrophotographic apparatus using the photoreceptor. <P>SOLUTION: The quinone compound has a structure expressed by general formula (I). In general formula (I), each of R<SP>1</SP>to R<SP>4</SP>represents a hydrogen atom, a 1-12C alkyl group or an aryl group, each of R<SP>5</SP>to R<SP>7</SP>represents a 1-12C alkyl group, an aryl group or a heterocyclic group, and m represents an integer 0 to 4. The compound may have, as a substituent, a halogen atom, nitro group, 1-6C alkyl group, aryl group, 1-6C halogenated alkyl group or 1-6C alkoxy group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

（式（Ｉ）中、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４は、同一または異なって、水素原子、置換基を有してもよい炭素数１〜１２のアルキル基、または置換基を有してもよいアリール基を表し、Ｒ^５、Ｒ^６およびＲ^７は、同一または異なって、置換基を有してもよい炭素数１〜１２のアルキル基、置換基を有してもよいアリール基、または置換基を有してもよい複素環基を表し、ｍは０〜４の整数を表し、置換基は、ハロゲン原子、ニトロ基、炭素数１〜６のアルキル基、アリール基、炭素数１〜６のハロゲン化アルキル基または炭素数１〜６のアルコキシ基を表す）で示される構造を有することを特徴とする新規キノン化合物である。
【００１８】
また、上記課題を解決するために、本発明は、導電性基体上に電荷発生物質および電荷輸送物質を含有する感光層を設けた電子写真用感光体において、該感光層が、下記一般式（Ｉ）、

（式（Ｉ）中、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４は、同一または異なって、水素原子、置換基を有してもよい炭素数１〜１２のアルキル基、または置換基を有してもよいアリール基を表し、Ｒ^５、Ｒ^６およびＲ^７は、同一または異なって、置換基を有してもよい炭素数１〜１２のアルキル基、置換基を有してもよいアリール基、または置換基を有してもよい複素環基を表し、ｍは０〜４の整数を表し、置換基は、ハロゲン原子、ニトロ基、炭素数１〜６のアルキル基、アリール基、炭素数１〜６のハロゲン化アルキル基または炭素数１〜６のアルコキシ基を表す）で示される化合物の少なくとも一種を含有することを特徴とする電子写真用感光体である。
【００１９】
【発明の実施の形態】
前記一般式（Ｉ）で示される化合物の具体例を、下記の構造式（Ｉ−１）〜（Ｉ−２０）にて示すが、本発明においては、これらの化合物に限定されるものではない。なお、下記の具体例中の

はｔ−ブチル基を表す。
【００２０】

【００２１】

【００２２】
本発明の化合物は、例えば、下記反応式（１）に従い合成することができる。即ち、まず、下記反応式（１）に示すように、構造式（Ａ）および／または（Ａ’）で示される化合物と構造式（Ｂ）で示される化合物とを適当な有機金属試薬（例えば、ｎ−ブチルリチウムなど）で反応させて、保護基（トリメチルシリル基：ＴＭＳ）を取り去ることにより、構造式（Ｃ）で示される化合物を合成する。その後、この構造式（Ｃ）で示される化合物を、適当な触媒（例えば、ｐ−トルエンスルホン酸（ｐ−ＴｓＯＨ）など）で脱水酸化することにより、構造式（ＩＡ）で示される化合物を合成することができる。なお、下記反応式（１）中の「ＴＢＡＦ」とはフッ化テトラブチルアンモニウムを表す。
【００２３】

【００２４】
以下、本発明の電子写真用感光体の実施の形態について図面を参照しつつ詳細に説明する。
図１および図２は、感光体の各種構成例を示す模式的断面図である。
図１は、いわゆる単層型感光体の一構成例を示しており、導電性基体１上に電荷発生物質と電荷輸送物質とを樹脂バインダ（結着剤）中に分散した単層の感光層２が設けられ、さらに、必要に応じて被覆層（保護層）６が積層されている。この単層型感光体は、電荷発生物質を電荷輸送物質および樹脂バインダを溶解した溶液中に分散せしめ、この分散液を導電性基体上に塗布することによって作製することができる。さらに、必要な場合には被覆層６を塗布形成することができる。
【００２５】
図２は、いわゆる積層型感光体の一構成例を示しており、導電性基体１上に、電荷発生物質を主体とする電荷発生層３と、電荷輸送物質を含有する電荷輸送層４とが順次積層された感光層５が設けられている。この積層型感光体は、導電性基体上に電荷発生物質を真空蒸着するか、または、電荷発生物質の粒子を溶剤または樹脂バインダ中に分散して得た分散液を塗布、乾燥して電荷発生層を形成し、次いで、その上に電荷輸送物質および樹脂バインダを溶解した溶液を塗布、乾燥して電荷輸送層を形成することにより作製することができる。
【００２６】
また、図示はしていないが、いずれのタイプの感光体においても、導電性基体と感光層との間に下引き層を設けることができる。下引き層は、導電性基体から感光層への不要な電荷の注入防止や、基体表面上の欠陥被覆、感光層の接着性向上等の目的で必要に応じて設けることができ、樹脂を主成分とする層やアルマイト等の酸化皮膜等からなる。
【００２７】
なお、本発明のいずれのタイプの感光体も、電荷輸送物質として、前記一般式（Ｉ）で示される本発明に係る電子輸送性を有する化合物の少なくとも一種を含有する。
【００２８】
以下、本発明の感光体の好適な実施の形態を図２に示す積層型感光体について説明するが、本発明は以下の具体例に限定されるものではない。
【００２９】
導電性基体１は、感光体の電極としての役目と同時に他の各層の支持体ともなっており、円筒状、板状、フィルム状のいずれでもよく、材質的にはアルミニウム、ステンレス鋼、ニッケルなどの金属や、ガラス、樹脂などの上に導電処理を施したものなどを用いることができる。
【００３０】
電荷発生層３は、前述したように電荷発生物質の粒子を樹脂バインダ中に分散させた材料を塗布するか、あるいは、真空蒸着するなどの方法により形成され、光を受容して電荷を発生する。また、その電荷発生効率が高いことと同時に発生した電荷の電荷輸送層４への注入性が重要であり、電場依存性が少なく、低電場でも注入の良いことが望ましい。
【００３１】
電荷発生物質としては、無金属フタロシアニン、チタニルフタロシアニンなどのフタロシアニン化合物、各種アゾ、キノン、インジゴ、シアニン、スクアリリウム、アズレニウム、ピリリウム化合物などの顔料あるいは染料や、セレンまたはセレン化合物などが用いられ、画像形成に使用される露光光源の光波長領域に応じて好適な物質を選ぶことができる。電荷発生層は電荷発生機能を有すればよいので、その膜厚は電荷発生物質の光吸収係数より決まり、一般的には５μｍ以下であり、好適には２μｍ以下である。さらに、電荷発生層は、電荷発生物質を主体としてこれに電荷輸送物質などを添加して使用することも可能である。
【００３２】
電荷発生層３用の樹脂バインダとしては、ポリカーボネート、ポリエステル、ポリアミド、ポリウレタン、塩化ビニル、フェノキシ樹脂、ポリビニルブチラール、ジアリルフタレート樹脂、メタクリル酸エステルの重合体および共重合体などを適宜組み合わせて使用することが可能である。
【００３３】
電荷輸送層４は、樹脂バインダ中に電荷輸送物質を分散させた塗膜であり、暗所では絶縁体層として感光体の電荷を保持し、光受容時には電荷発生層から注入される電荷を輸送する機能を発揮する。前述したように、本発明においては、かかる電荷輸送物質として、本発明に係る前記一般式（Ｉ）で示される電子輸送性を有する化合物の少なくとも一種を含有させることが必要であるが、他の電荷輸送物質を含有させてもよい。本発明に係る化合物の好適添加量は、電荷輸送層４中に含まれる材料全体に対して、好適には１０〜６０重量％であり、より好適には１５〜５０重量％である。
【００３４】
電荷輸送層４用の樹脂バインダとしては、ポリカーボネート、ポリエステル、ポリスチレン、メタクリル酸エステルの重合体および共重合体などを用いることができる。
【００３５】
また、感光体を使用する際に使用上障害となるオゾン劣化などを防止する目的で、電荷輸送層４にアミン系、フェノール系、硫黄系、亜リン酸エステル系、リン系などの酸化防止剤を含有させることも可能である。
【００３６】
図１に示す被覆層６は、暗所ではコロナ放電の電荷を受容して保持する機能を有しており、かつ、感光層が感応する光を透過する性能を有し、露光時に光を透過して感光層に到達させ、発生した電荷の注入を受けて表面電荷を中和消滅させることが必要である。被覆層の材料としては、有機系の材料として、ポリエステル、ポリアミドなどの有機絶縁性皮膜形成材料を適用することができる。また、これら有機材料と、ガラス、ＳｉＯ_２などの無機材料、さらには金属、金属酸化物などの電気抵抗を低減せしめる材料とを混合して用いることができる。無機系の材料としては、非晶質のケイ素−炭素（ＳｉＣ）複合膜被覆層等の気相成長法によって成膜された層などを適用することができる。被覆層は、上述の通り電荷発生物質の光の吸収極大の波長領域においてできるだけ透明であることが望ましい。
【００３７】
被覆層自体の膜厚は、被覆層の配合組成にも依存するが、繰り返し連続使用したとき残留電位が増大するなどの悪影響が出ない範囲で任意に設定することができる。
【００３８】
尚、図１に示す単層型感光体の場合においても、前記一般式（Ｉ）で示される本発明に係る電子輸送性を有する化合物の少なくとも一種を感光層２中に含有させることが必要であるが、その他の材料等は、上述の積層型感光体と同様のものを用いることができ、特に制限されるものではない。好適には、電荷輸送物質として前記一般式（Ｉ）の化合物と共に、正孔輸送物質を含有させる。正孔輸送物質としては、ベンジジン誘導体やトリフェニルアミン誘導体などが好ましい。この場合、これらの好適添加量としては、感光層形成塗膜中に含まれる材料全体に対して、本発明に係る化合物については好適には１０〜６０重量％であり、より好適には１５〜５０重量％であり、正孔輸送物質については好適には１０〜６０重量％であり、より好適には２０〜５０重量％である。
【００３９】
また、感光体の表面層（被覆層を設けた場合には被覆層、被覆層を設けない場合には最外層にあたる感光層）には、レベリング材として、シリコーンオイルを添加したり、潤滑性を付与する等の目的で、シリコーンオイル、四フッ化エチレン等のフッ素樹脂微粒子、シリコーン樹脂微粒子、フッ素系クシ型グラフトポリマー等のシリコンやフッ素を含有するポリマーを含有させることが可能である。
【００４０】
【実施例】
以下、本発明の実施例について説明する。
合成実施例１：前記具体例（Ｉ−２）の化合物の合成
下記反応式（１−１）に従い、前記具体例（Ｉ−２）で示される化合物を合成した。
【００４１】

【００４２】
▲１▼４−ブロモ−２，６−ジ−ｔ−ブチル−１−（トリメチルシロキシ）ベンゼン（Ａ−１）４４ｍｍｏｌ（１５．６ｇ）のＴＨＦ溶液に、−７８℃、窒素雰囲気下で、１．６Ｍ ｎ−ブチルリチウムヘキサン溶液（ｎ−ＢｕＬｉ）４８ｍｍｏｌ（３０ｍｌ）を加えて攪拌後、ジベンゾイルベンゼン（Ｂ−１）１７ｍｍｏｌ（４．８８ｇ）を加えて３時間攪拌し、室温で１時間攪拌した。少量の飽和塩化アンモニウム水溶液を加えて反応を終了した。さらに、１．０Ｍフッ化テトラブチルアンモニウムＴＨＦ溶液（ＴＢＡＦ）４４ｍｍｏｌ（４４ｍｌ）を加えて攪拌後、塩酸水へ注ぎ、ジクロロメタンで抽出し濃縮することにより、粗生成物として、構造式（Ｃ−１）で表される化合物を得た。
【００４３】
▲２▼さらに、上記構造式（Ｃ−１）で表される化合物のＴＨＦ溶液に、少量のｐ−トルエンスルホン酸（ｐ−ＴｓＯＨ）を加えて、加熱還流した。その後、反応液を塩酸水へ注ぎ、ジクロロメタンで抽出後、濃縮して得られた固形分をクロロホルムとエタノールとの混合液で再結晶することにより、前記構造式（Ｉ−２）で表される化合物を得た。収量 ７．２ｇ（収率６２．１％）、ＭＳ ｍ／ｚ ６６２（Ｍ＋）であった。この具体例（Ｉ−２）の化合物のＩＲスペクトルを図３に、^１Ｈ−ＮＭＲスペクトルを図４に、夫々示す。
【００４４】
合成実施例２：前記具体例（Ｉ−７）の化合物の合成
上記合成実施例１のジベンゾイルベンゼンを４、４’−ジクロロベンゾイルベンゼンに代えた以外は、合成実施例１と同様の操作を行い、前記式（Ｉ−７）で表される化合物を得た。収率４３．５％、ＭＳ ｍ／ｚ ７３０（Ｍ＋）であった。この具体例（Ｉ−７）の化合物のＩＲスペクトルを図５に、^１Ｈ−ＮＭＲスペクトルを図６に、夫々示す。
【００４５】
なお、上記合成実施例で用いた４−ブロモ−２，６−ジ−ｔｅｒｔ−ブチル−１−（トリメチルシロキシ）ベンゼン（前記構造式（Ａ−１））は、例えば、前記特許文献１５等に記載の公知の方法によって合成することができる。
【００４６】
感光体実施例１
アルミニウム板およびアルミニウム素管上に、夫々、可溶性ナイロン（アミランＣＭ８０００：東レ（株）製）３重量部、メタノール／塩化メチレン混合溶剤（５／５）９７重量部の組成の下引き層溶液を浸漬塗工し、１００℃で６０分乾燥して、膜厚０．３μｍの下引き層を形成した。
【００４７】
次に、この下引き層上に、以下の組成の単層型感光層分散液を浸漬塗工し、１００℃で６０分乾燥して、膜厚２５μｍの単層型感光層を形成した。
電荷発生物質：Ｘ型無金属フタロシアニン ０．３重量部
（特開２００１−２２８６３７号公報中の図２参照）
正孔輸送物質：下記構造式（ＨＴ１−１０１）、

で示されるトリフェニルアミン化合物 ７重量部
（特開２０００−３１４９６９号公報中の（ＨＴ１−１０１））
電子輸送物質：前記式（Ｉ−２）で示される化合物 ３重量部
酸化防止剤 ：３，５−ジ−ｔｅｒｔ−４−ヒドロキシトルエン（ＢＨＴ）
（東京化成工業（株）製） １重量部
シリコーンオイル：ＫＦ−５０（信越化学工業（株）製） ０．０１重量部
バインダー樹脂：ビスフェノールＺ型ポリカーボネート樹脂
（パンライトＴＳ２０２０：帝人化成（株）製） １０重量部
（特開２０００−３１４９６９号公報中の（ＢＤ１−１））
塩化メチレン １００重量部
以上のようにして電子写真用感光体を作製した。
【００４８】
感光体実施例２
感光体実施例１で使用した感光層分散液の組成のうち、電子輸送物質としての前記構造式（Ｉ−２）で示される化合物３重量部を、前記構造式（Ｉ−７）で示される化合物３重量部に代えた以外は感光体実施例１と同様にして、単層型感光体を作製した。
【００４９】
感光体実施例３
感光体実施例１で使用した感光層分散液の組成のうち、電子輸送物質としての前記構造式（Ｉ−２）で示される化合物３重量部を、前記構造式（Ｉ−８）で示される化合物３重量部に代えた以外は感光体実施例１と同様にして、単層型感光体を作製した。
【００５０】
感光体実施例４
感光体実施例１で使用した感光層分散液の組成のうち、電荷発生物質としてのＸ型無金属フタロシアニン０．３重量部を、Ｙ型チタニルフタロシアニン（特開２００１−２２８６３７号公報中の図４参照）０．２重量部に代えた以外は感光体実施例１と同様にして、単層型感光体を作製した。
【００５１】
感光体実施例５
感光体実施例１で使用した感光層分散液の組成のうち、正孔輸送物質としての前記構造式（ＨＴ１−１０１）で示されるトリフェニルアミン化合物７重量部を、下記構造式（ＨＴ２−２）、

で示されるスチリル化合物（特開２０００−３１４９６９号公報中の（ＨＴ２−２））７重量部に代えた以外は感光体実施例１と同様にして、単層型感光体を作製した。
【００５２】
感光体実施例６
感光体実施例１で使用した感光層分散液の組成のうち、正孔輸送物質としての前記構造式（ＨＴ１−１０１）で示されるトリフェニルアミン化合物７重量部を、下記構造式（ＨＴ−１１）、

で示されるベンジジン誘導体（特開２０００−３１４９６９号公報中の（ＨＴ−１１））７重量部に代えた以外は感光体実施例１と同様にして、単層型感光体を作製した。
【００５３】
感光体実施例７
感光体実施例１で使用した感光層分散液の組成のうち、電荷発生物質としてのＸ型無金属フタロシアニン０．３重量部を、アモルファスチタニルフタロシアニン（特開２００１−２２８６３７号公報中の図５参照）０．２重量部に代えた以外は感光体実施例１と同様にして、単層型感光体を作製した。
【００５４】
感光体実施例８
感光体実施例１で使用した感光層分散液の組成のうち、電荷発生物質としてのＸ型無金属フタロシアニン０．３重量部を、下記式（ＣＧ１−１）、

で示されるビスアゾ顔料に代えた以外は感光体実施例１と同様にして、単層型感光体を作製した。
【００５５】
感光体実施例１〜８の評価
電気特性評価用として板状感光体を用いて、（株）川口電機製作所製 静電複写紙試験装置ＥＰＡ−８１００にて評価を行った。
まず、温度２３℃、湿度４５％の環境下で、暗所にて表面電位を約＋６００Ｖになるように帯電させ、その後露光までの５秒間の表面電位の保持率を次式より求めた。
保持率Ｖ_ｋ５（％）＝（Ｖ_５／Ｖ_０）×１００
Ｖ_０：帯電直後の表面電位
Ｖ_５：５秒後（露光開始時）の表面電位
【００５６】
次に、同様に表面電位を＋６００Ｖにして、ハロゲンランプの光をフィルターにて７８０ｎｍに分光した１．０μＷ／ｃｍ^２の単色光を５秒間露光して、表面電位が半分（＋３００Ｖ）になるのに要する露光量を感度Ｅ_１／２（μＪ／ｃｍ^２）として求め、露光後５秒後の表面電位を残留電位Ｖ_ｒ（Ｖ）として求めた。
この評価結果を下記の表１中に示す。
【００５７】
【表１】

【００５８】
また、実際の印字による耐久性の評価として、ドラム状感光体（３０ｍｍφ）を用いた。各ドラム状感光体をブラザー工業（株）製 レーザープリンターＨＬ−１２４０に装着し、温度２２℃、湿度４４％の環境下で、黒ベタ画像、白ベタ画像、ハーフトーン画像を印刷した。続いて、印字率約５％の画像を５千枚印刷し、その後再び、黒ベタ画像、白ベタ画像、ハーフトーン画像を印刷して、５千枚印字後の画像評価を行った。
【００５９】
結果として、感光体実施例１〜８の感光体は、初期画像および５千枚後の画像の双方において、良好な画像が得られた。
【００６０】
なお、感光体実施例８については、使用したレーザープリンターのレーザー波長域（７８０ｎｍ付近）に十分な感度を有しておらず、このレーザープリンターには不向きであることが判った。
【００６１】
【発明の効果】
以上説明してきたように、本発明によれば、電子輸送性に優れた化合物を得ることができ、この化合物を、電子写真用感光体等の有機化合物を用いた電子デバイスに適用することにより、電気特性等を向上することが可能となる。また、本発明によれば、導電性基体上に設けた感光層中に電荷輸送物質としてこの化合物を用いたことにより、正帯電において高感度で電気特性に優れた感光体を得ることが可能となった。また、電荷発生物質は露光光源の種類に対応して好適な物質を選ぶことができ、フタロシアニン化合物、スクアリリウム化合物、ビスアゾ化合物などを用いることにより、半導体レーザープリンターや複写機に使用可能な感光体を得ることができる。さらに、必要に応じて表面に被覆層を設置して耐久性を向上することが可能である。
【図面の簡単な説明】
【図１】単層型電子写真用感光体を示す概念的断面図である。
【図２】積層型電子写真用感光体を示す概念的断面図である。
【図３】構造式（Ｉ−２）で示される化合物のＩＲスペクトルである。
【図４】構造式（Ｉ−２）で示される化合物の^１Ｈ−ＮＭＲスペクトルである。
【図５】構造式（Ｉ−７）で示される化合物のＩＲスペクトルである。
【図６】構造式（Ｉ−７）で示される化合物の^１Ｈ−ＮＭＲスペクトルである。
【符号の説明】
１ 導電性基体
２ 感光層
３ 電荷発生層
４ 電荷輸送層
５ 感光層（積層）
６ 被覆層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel quinone compound, and more particularly to a novel quinone compound useful as an electron transport material such as an electrophotographic photoreceptor (hereinafter also simply referred to as “photoreceptor”). The present invention also relates to an electrophotographic photoreceptor and an electrophotographic apparatus. More specifically, the present invention relates to an electrophotographic photosensitive member used in an electrophotographic printer, a copying machine, or the like, in which a photosensitive layer containing an organic material is provided on a conductive substrate. Body and electrophotographic apparatus.
[0002]
[Prior art]
Conventionally, a photosensitive layer of an electrophotographic photosensitive member in which an inorganic photoconductive substance such as selenium or a selenium alloy or an inorganic photoconductive substance such as zinc oxide or cadmium sulfide is dispersed in a resin binder is used. Has been. In recent years, research on electrophotographic photoreceptors using organic photoconductive materials has progressed, and some have been put into practical use with improved sensitivity and durability.
[0003]
In addition, the photoreceptor must have a function of retaining surface charges in the dark, a function of receiving light to generate charges, and a function of receiving light and transporting charges. Functionally separated into a so-called single-layer type photoconductor that combines these functions with a layer, and a layer that mainly contributes to charge generation and a layer that contributes to the maintenance of surface charge in the dark and charge transport during photoreception. There is a so-called multi-layer photoreceptor in which the above are laminated.
[0004]
For example, the Carlson method is applied to image formation by electrophotography using these photoreceptors. In this method, the image is formed by charging the photoconductor in the dark by corona discharge, forming an electrostatic latent image such as text or a picture of an original on the charged photoconductor surface, and forming a static image. The electrostatic latent image was developed by toner and the developed toner image was fixed on a support such as paper. The photoconductor after the toner image was transferred was subjected to charge removal, residual toner removal, and light charge removal. Later, it is used again.
[0005]
Organic photoreceptors in practical use have advantages such as flexibility, film formation, low cost, and safety compared to inorganic photoreceptors, and further improvements in sensitivity and durability are possible due to the variety of materials. It is being advanced.
[0006]
Most of the organic photoreceptors are stacked organic photoreceptors in which functions are separated into a charge generation layer and a charge transport layer. In general, in a multilayer organic photoreceptor, a charge generation layer containing a charge generation material such as a pigment or a dye and a charge transport layer containing a charge transport material such as hydrazone or triphenylamine are sequentially formed on a conductive substrate. In view of the nature of the electron-donating charge transport material, it is a hole transfer type and has sensitivity when the surface of the photoreceptor is negatively charged. However, in the negatively charged type, corona discharge used for charging is unstable compared to the positively charged type, and in order to generate ozone, nitrogen oxides, etc., these are adsorbed on the surface of the photoconductor, There is a problem that it is easy to cause chemical deterioration and further deteriorates the environment. From this point of view, the positively charged type photoconductor having a greater degree of freedom of use conditions is more advantageous as the photoconductor than the negatively charged type photoconductor.
[0007]
Thus, for use in the positively charged type, a method has been proposed in which a charge generation material and a charge transport material are simultaneously dispersed in a resin binder and used as a single photosensitive layer, and some have been put into practical use. However, the single-layer type photoreceptor is not sufficiently sensitive to be applied to a high-speed machine, and further improvement is required from the viewpoint of repeatability.
[0008]
In addition, in order to achieve a function separation type laminated structure for the purpose of increasing sensitivity, a method of forming a photoconductor by laminating a charge generation layer on a charge transport layer and using it in a positively charged type is also considered. However, since the charge generation layer is formed on the surface, problems such as corona discharge, light irradiation, mechanical wear, and the like occur in stability during repeated use. In this case, it has been proposed to further provide a protective layer on the charge generation layer. However, although mechanical wear is improved, problems such as a decrease in electrical characteristics such as sensitivity have not been solved.
[0009]
Furthermore, a method of forming a photoconductor by laminating an electron transporting charge transport layer on a charge generation layer has also been proposed.
[0010]
As an electron transporting charge transporting material, for example, 2,4,7-trinitro-9-fluorenone is known. However, since this substance has carcinogenicity, there is a safety problem. In addition, in Patent Documents 1 to 4 and the like, cyano compounds and quinone compounds have been proposed, but those having an electron transport ability sufficient for practical use have not been obtained.
[0011]
Furthermore, for example, in Patent Document 5 to Patent Document 15, Non-Patent Document 1 to Non-Patent Document 4, etc., many electron transport materials and electrophotographic photoreceptors using the same have been proposed, described, and attract attention. It is becoming. In addition, in a single-layer type photosensitive layer, for example, a photoreceptor using a combination of a hole transporting material and an electron transporting material as described in Patent Document 16 to Patent Document 20 is noted as having high sensitivity. Some have been put to practical use.
[0012]
In contrast, the present inventors have proposed various photoreceptors containing substances having excellent electron transport properties (for example, described in Patent Documents 21 to 24).
[0013]
[Patent Document 1]
JP-A-1-206349
[Patent Document 2]
JP-A-6-59483
[Patent Document 3]
JP-A-9-190002
[Patent Document 4]
JP-A-9-190003
[Patent Document 5]
JP-A-4-360148
[Patent Document 6]
JP-A-3-290666
[Patent Document 7]
JP-A-5-92936
[Patent Document 8]
JP-A-9-151157
[Patent Document 9]
JP-A-5-279582
[Patent Document 10]
JP-A-7-179775
[Patent Document 11]
Japanese Patent Laid-Open No. 10-73937
[Patent Document 12]
JP-A-4-338760
[Patent Document 13]
JP-A-1-230054
[Patent Document 14]
JP-A-8-278743
[Patent Document 15]
JP 2001-222122 A
[Patent Document 16]
Japanese Patent Laid-Open No. 5-150481
[Patent Document 17]
JP-A-6-130688
[Patent Document 18]
JP-A-9-281728
[Patent Document 19]
JP-A-9-281729
[Patent Document 20]
JP-A-10-239874
[Patent Document 21]
JP 2000-75520 A
[Patent Document 22]
JP 2000-199979 A
[Patent Document 23]
JP 2000-143607 A
[Patent Document 24]
JP 2001-142239 A
[Non-Patent Document 1]
The Journal of Electrophotographic Society Vol. 30, p266-273 (1991)
[Non-Patent Document 2]
Pan-Pacific Imaging Conference / Japan Hardcopy '98 July 15-17, 1998 JAHALL, Tokyo, Japan Proceedings p207-210
[Non-Patent Document 3]
Japan Hardcopy'97 Proceedings July 9, 10 and 11, 1997 JA Hall (Otemachi, Tokyo) p21-24
[Non-Patent Document 4]
Japan Hardcopy '92 Proceedings July 6, 7, and 1992 JA Hall (Otemachi, Tokyo) p173-176
[0014]
[Problems to be solved by the invention]
However, due to the recent demand for a high-sensitivity photoconductor, it has been required to realize a high-performance photoconductor by using a new charge transport material having better electron transport properties.
[0015]
Accordingly, an object of the present invention is to provide a compound having excellent electron transport ability useful for electrophotographic photoreceptor applications, and by using such a novel organic material as a charge transport material in a photosensitive layer, It is an object of the present invention to provide a positively charged electrophotographic photoreceptor for high-sensitivity copying machines and printers and an electrophotographic apparatus using the same.
[0016]
[Means for Solving the Problems]
As a result of intensive studies on various organic materials to achieve the above object, the present inventors have used a compound having a specific electron transport property represented by the following general formula (I) as a charge transport material. The inventors have found that a high-sensitivity photoreceptor that can be used with positive charging can be obtained, and have completed the present invention.
[0017]
That is, in order to solve the above problems, the present invention provides the following general formula (I),

(In the formula (I), R¹, R², R³And R⁴Are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an aryl group which may have a substituent;⁵, R⁶And R⁷Are the same or different and each represents an optionally substituted alkyl group having 1 to 12 carbon atoms, an optionally substituted aryl group, or an optionally substituted heterocyclic group; m represents an integer of 0 to 4, and the substituent is a halogen atom, a nitro group, an alkyl group having 1 to 6 carbon atoms, an aryl group, a halogenated alkyl group having 1 to 6 carbon atoms, or an alkoxy having 1 to 6 carbon atoms. A novel quinone compound characterized by having a structure represented by:
[0018]
In order to solve the above-mentioned problems, the present invention provides an electrophotographic photoreceptor in which a photosensitive layer containing a charge generating substance and a charge transporting substance is provided on a conductive substrate, and the photosensitive layer has the following general formula ( I),

(In the formula (I), R¹, R², R³And R⁴Are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an aryl group which may have a substituent;⁵, R⁶And R⁷Are the same or different and each represents an optionally substituted alkyl group having 1 to 12 carbon atoms, an optionally substituted aryl group, or an optionally substituted heterocyclic group; m represents an integer of 0 to 4, and the substituent is a halogen atom, a nitro group, an alkyl group having 1 to 6 carbon atoms, an aryl group, a halogenated alkyl group having 1 to 6 carbon atoms, or an alkoxy having 1 to 6 carbon atoms. An electrophotographic photoreceptor characterized in that it contains at least one of the compounds represented by the formula:
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Specific examples of the compound represented by the general formula (I) are shown by the following structural formulas (I-1) to (I-20). However, the present invention is not limited to these compounds. . In the following specific examples

Represents a t-butyl group.
[0020]

[0021]

[0022]
The compound of the present invention can be synthesized, for example, according to the following reaction formula (1). That is, first, as shown in the following reaction formula (1), the compound represented by the structural formula (A) and / or (A ′) and the compound represented by the structural formula (B) are combined with an appropriate organometallic reagent (for example, , N-butyllithium, etc.) to remove the protecting group (trimethylsilyl group: TMS) to synthesize a compound represented by the structural formula (C). Thereafter, the compound represented by the structural formula (C) is synthesized by dehydrating and oxidizing the compound represented by the structural formula (C) with an appropriate catalyst (for example, p-toluenesulfonic acid (p-TsOH)). can do. In addition, “TBAF” in the following reaction formula (1) represents tetrabutylammonium fluoride.
[0023]

[0024]
Hereinafter, embodiments of the electrophotographic photoreceptor of the present invention will be described in detail with reference to the drawings.
1 and 2 are schematic cross-sectional views showing various configuration examples of the photoreceptor.
FIG. 1 shows an example of the structure of a so-called single-layer type photoreceptor, in which a single-layer photosensitive layer in which a charge generation material and a charge transport material are dispersed in a resin binder (binder) on a conductive substrate 1. 2 is further provided, and a coating layer (protective layer) 6 is laminated as necessary. This single-layer type photoreceptor can be produced by dispersing a charge generating substance in a solution in which a charge transporting substance and a resin binder are dissolved, and applying this dispersion onto a conductive substrate. Further, the coating layer 6 can be applied and formed if necessary.
[0025]
FIG. 2 shows an example of the structure of a so-called multilayer photoreceptor, in which a charge generation layer 3 mainly composed of a charge generation material and a charge transport layer 4 containing a charge transport material are formed on a conductive substrate 1. A photosensitive layer 5 that is sequentially laminated is provided. This layered type photoreceptor generates charge by vacuum-depositing a charge generation material on a conductive substrate, or by applying and drying a dispersion obtained by dispersing charge generation material particles in a solvent or resin binder. A layer can be formed, and then a solution in which a charge transport material and a resin binder are dissolved is applied thereon and dried to form a charge transport layer.
[0026]
Although not shown, an undercoat layer can be provided between the conductive substrate and the photosensitive layer in any type of photoreceptor. The undercoat layer can be provided as necessary for the purpose of preventing injection of unnecessary charges from the conductive substrate to the photosensitive layer, covering defects on the substrate surface, and improving the adhesion of the photosensitive layer. It consists of a layer as an ingredient and an oxide film such as alumite.
[0027]
In addition, any type of the photoreceptor of the present invention contains at least one of the compounds having an electron transporting property according to the present invention represented by the general formula (I) as a charge transport material.
[0028]
Hereinafter, a preferred embodiment of the photoreceptor of the present invention will be described with reference to the multilayer photoreceptor shown in FIG. 2, but the present invention is not limited to the following specific examples.
[0029]
The conductive substrate 1 serves as a support for each of the other layers as well as serving as an electrode of the photoreceptor, and may be any of a cylindrical shape, a plate shape, and a film shape, and materials such as aluminum, stainless steel, nickel, etc. A metal, glass, resin, or the like subjected to a conductive treatment can be used.
[0030]
The charge generation layer 3 is formed by applying a material in which particles of a charge generation material are dispersed in a resin binder as described above, or by vacuum deposition, and generates charge by receiving light. . In addition, the injection efficiency of the generated charges into the charge transport layer 4 is important at the same time as the charge generation efficiency is high, and there is little electric field dependency, and it is desirable that the injection is good even at a low electric field.
[0031]
As the charge generation material, phthalocyanine compounds such as metal-free phthalocyanine and titanyl phthalocyanine, pigments or dyes such as various azo, quinone, indigo, cyanine, squarylium, azurenium and pyrylium compounds, selenium or selenium compounds, etc. are used for image formation. A suitable substance can be selected according to the light wavelength region of the exposure light source used for the above. Since the charge generation layer only needs to have a charge generation function, the thickness thereof is determined by the light absorption coefficient of the charge generation material, and is generally 5 μm or less, and preferably 2 μm or less. Further, the charge generation layer can be used mainly with a charge generation material added with a charge transport material.
[0032]
As the resin binder for the charge generation layer 3, a polycarbonate, polyester, polyamide, polyurethane, vinyl chloride, phenoxy resin, polyvinyl butyral, diallyl phthalate resin, a polymer and a copolymer of methacrylic acid ester, and the like may be used in appropriate combination. Is possible.
[0033]
The charge transport layer 4 is a coating film in which a charge transport material is dispersed in a resin binder. The charge transport layer 4 retains the charge of the photoreceptor as an insulator layer in the dark, and transports the charge injected from the charge generation layer when receiving light. Demonstrate the function to do. As described above, in the present invention, as the charge transport material, it is necessary to contain at least one kind of the compound having an electron transport property represented by the general formula (I) according to the present invention. A charge transport material may be included. The preferred addition amount of the compound according to the present invention is preferably 10 to 60% by weight, more preferably 15 to 50% by weight, based on the entire material contained in the charge transport layer 4.
[0034]
As the resin binder for the charge transport layer 4, a polymer, a copolymer, or the like of polycarbonate, polyester, polystyrene, and methacrylic acid ester can be used.
[0035]
Further, for the purpose of preventing ozone deterioration, which is an obstacle to use when using a photoreceptor, an antioxidant such as amine, phenol, sulfur, phosphite, or phosphorus is added to the charge transport layer 4. It is also possible to contain.
[0036]
The coating layer 6 shown in FIG. 1 has a function of receiving and holding the electric charge of corona discharge in a dark place, and has a capability of transmitting light sensitive to the photosensitive layer, and transmits light during exposure. Thus, it is necessary to reach the photosensitive layer and neutralize and extinguish the surface charge upon receiving the generated charge injection. As a material for the coating layer, an organic insulating film forming material such as polyester or polyamide can be applied as an organic material. Also, these organic materials, glass, SiO₂Inorganic materials such as metals, and materials that reduce electrical resistance, such as metals and metal oxides, can also be mixed and used. As the inorganic material, a layer formed by a vapor deposition method such as an amorphous silicon-carbon (SiC) composite film coating layer or the like can be used. As described above, it is desirable that the coating layer be as transparent as possible in the wavelength region of the light absorption maximum of the charge generation material.
[0037]
The film thickness of the coating layer itself depends on the blend composition of the coating layer, but can be arbitrarily set within a range where no adverse effect such as an increase in residual potential occurs when it is repeatedly used continuously.
[0038]
Even in the case of the single layer type photoreceptor shown in FIG. 1, it is necessary that the photosensitive layer 2 contains at least one kind of the compound having the electron transporting property represented by the general formula (I) according to the present invention. However, the other materials and the like can be the same as those of the above-described laminated photoreceptor, and are not particularly limited. Preferably, a hole transport material is contained together with the compound of the general formula (I) as a charge transport material. As the hole transport material, a benzidine derivative, a triphenylamine derivative, or the like is preferable. In this case, these preferred addition amounts are preferably 10 to 60% by weight, more preferably 15 to the compound according to the present invention with respect to the entire material contained in the photosensitive layer forming coating film. It is 50% by weight, and the hole transport material is preferably 10 to 60% by weight, and more preferably 20 to 50% by weight.
[0039]
In addition, silicone oil can be added as a leveling material to the surface layer of the photoreceptor (a coating layer when a coating layer is provided, or a photosensitive layer that is the outermost layer when a coating layer is not provided), or lubricity can be increased. For the purpose of imparting, it is possible to contain silicon or fluorine-containing polymers such as silicone oil, fluororesin fine particles such as tetrafluoroethylene, silicone resin fine particles, and fluorine-based comb type graft polymer.
[0040]
【Example】
Examples of the present invention will be described below.
Synthesis Example 1: Synthesis of compound of specific example (I-2)
The compound represented by the specific example (I-2) was synthesized according to the following reaction formula (1-1).
[0041]

[0042]
(1) 4-bromo-2,6-di-tert-butyl-1- (trimethylsiloxy) benzene (A-1) 44 mmol (15.6 g) in THF solution at −78 ° C. under nitrogen atmosphere Then, 48 mmol (30 ml) of 6M n-butyllithium hexane solution (n-BuLi) was added and stirred, then 17 mmol (4.88 g) of dibenzoylbenzene (B-1) was added and stirred for 3 hours, and stirred at room temperature for 1 hour. did. A small amount of saturated aqueous ammonium chloride solution was added to terminate the reaction. Furthermore, 44 mmol (44 ml) of 1.0 M tetrabutylammonium fluoride THF (TBAF) was added and stirred, and then poured into hydrochloric acid, extracted with dichloromethane, and concentrated to give a crude product as a structural formula (C-1 ) Was obtained.
[0043]
(2) Further, a small amount of p-toluenesulfonic acid (p-TsOH) was added to a THF solution of the compound represented by the structural formula (C-1), and the mixture was heated to reflux. Thereafter, the reaction solution is poured into aqueous hydrochloric acid, extracted with dichloromethane, and then concentrated, and the solid content obtained by recrystallization from a mixed solution of chloroform and ethanol is represented by the structural formula (I-2). A compound was obtained. Yield 7.2 g (62.1% yield), MS m / z 662 (M +). The IR spectrum of the compound of this specific example (I-2) is shown in FIG.¹The H-NMR spectrum is shown in FIG.
[0044]
Synthesis Example 2: Synthesis of compound of specific example (I-7)
A compound represented by the formula (I-7) was obtained in the same manner as in Synthesis Example 1 except that the dibenzoylbenzene in Synthesis Example 1 was replaced with 4,4′-dichlorobenzoylbenzene. . Yield 43.5%, MS m / z 730 (M +). FIG. 5 shows an IR spectrum of the compound of this specific example (I-7).¹The H-NMR spectrum is shown in FIG.
[0045]
Note that 4-bromo-2,6-di-tert-butyl-1- (trimethylsiloxy) benzene (the structural formula (A-1)) used in the synthesis examples is described in, for example, Patent Document 15 and the like. It can be synthesized by the known methods described.
[0046]
Photoconductor Example 1
An undercoat layer solution of 3 parts by weight of soluble nylon (Amilan CM8000: manufactured by Toray Industries, Inc.) and 97 parts by weight of a methanol / methylene chloride mixed solvent (5/5) is immersed on the aluminum plate and the aluminum base tube, respectively. It was coated and dried at 100 ° C. for 60 minutes to form an undercoat layer having a thickness of 0.3 μm.
[0047]
Next, a single layer type photosensitive layer dispersion having the following composition was dip coated on this undercoat layer and dried at 100 ° C. for 60 minutes to form a single layer type photosensitive layer having a thickness of 25 μm.
Charge generation material: X-type metal-free phthalocyanine 0.3 parts by weight
(Refer to FIG. 2 in Japanese Patent Laid-Open No. 2001-228637)
Hole transport material: Structural formula below (HT1-101),

7 parts by weight of a triphenylamine compound represented by
((HT1-101) in JP 2000-314969 A)
Electron transport material: 3 parts by weight of the compound represented by the formula (I-2)
Antioxidant: 3,5-di-tert-4-hydroxytoluene (BHT)
(Tokyo Chemical Industry Co., Ltd.) 1 part by weight
Silicone oil: KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.01 parts by weight
Binder resin: Bisphenol Z-type polycarbonate resin
(Panlite TS2020: manufactured by Teijin Chemicals Ltd.) 10 parts by weight
((BD1-1) in JP 2000-314969 A)
100 parts by weight of methylene chloride
An electrophotographic photoreceptor was produced as described above.
[0048]
Photoconductor Example 2
Of the composition of the photosensitive layer dispersion used in Photoreceptor Example 1, 3 parts by weight of the compound represented by the structural formula (I-2) as an electron transporting material is represented by the structural formula (I-7). A single layer type photoreceptor was produced in the same manner as in photoreceptor example 1 except that the amount was changed to 3 parts by weight of the compound.
[0049]
Photoconductor Example 3
Of the composition of the photosensitive layer dispersion used in Photoreceptor Example 1, 3 parts by weight of the compound represented by the structural formula (I-2) as an electron transporting material is represented by the structural formula (I-8). A single layer type photoreceptor was produced in the same manner as in photoreceptor example 1 except that the amount was changed to 3 parts by weight of the compound.
[0050]
Photoconductor Example 4
Of the composition of the photosensitive layer dispersion used in Photoreceptor Example 1, 0.3 part by weight of X-type metal-free phthalocyanine as a charge generating material was added to Y-type titanyl phthalocyanine (FIG. 4 in JP-A No. 2001-228637). Reference) A single-layer photoreceptor was produced in the same manner as in photoreceptor Example 1 except that the content was changed to 0.2 parts by weight.
[0051]
Photoconductor Example 5
Of the composition of the photosensitive layer dispersion used in Photoreceptor Example 1, 7 parts by weight of the triphenylamine compound represented by the structural formula (HT1-101) as a hole transporting substance was replaced by the following structural formula (HT2-2). ),

A single layer type photoconductor was prepared in the same manner as in Photoconductor Example 1 except that 7 parts by weight of the styryl compound represented by formula ((HT2-2) in JP-A No. 2000-314969) was used.
[0052]
Photoconductor Example 6
Of the composition of the photosensitive layer dispersion used in Photoreceptor Example 1, 7 parts by weight of the triphenylamine compound represented by the structural formula (HT1-101) as a hole transporting substance was replaced by the following structural formula (HT-11). ),

A single-layer type photoreceptor was produced in the same manner as in photoreceptor example 1 except that 7 parts by weight of the benzidine derivative ((HT-11) in JP-A No. 2000-314969) shown in FIG.
[0053]
Photoconductor Example 7
Of the composition of the photosensitive layer dispersion used in Photoreceptor Example 1, 0.3 part by weight of X-type metal-free phthalocyanine as a charge generating material was added to amorphous titanyl phthalocyanine (see FIG. 5 in JP-A No. 2001-228637). ) A single layer type photoconductor was prepared in the same manner as in Photoconductor Example 1 except that the content was changed to 0.2 parts by weight.
[0054]
Photoconductor Example 8
Of the composition of the photosensitive layer dispersion used in Photoreceptor Example 1, 0.3 part by weight of X-type metal-free phthalocyanine as a charge generating material is represented by the following formula (CG1-1),

A single-layer type photoreceptor was produced in the same manner as in photoreceptor example 1 except that the bisazo pigment represented by
[0055]
Evaluation of photoreceptor examples 1 to 8
Evaluation was carried out with an electrostatic copying paper test apparatus EPA-8100 manufactured by Kawaguchi Electric Co., Ltd., using a plate-like photoreceptor for evaluation of electric characteristics.
First, in an environment of a temperature of 23 ° C. and a humidity of 45%, the surface potential was charged to be about +600 V in a dark place, and the retention rate of the surface potential for 5 seconds until the exposure was obtained from the following formula.
Retention rate V_k5(%) = (V₅/ V₀) × 100
V₀: Surface potential immediately after charging
V₅: Surface potential after 5 seconds (at the start of exposure)
[0056]
Next, similarly, the surface potential was set to +600 V, and the light of the halogen lamp was separated into 780 nm by a filter and 1.0 μW / cm.²The amount of exposure required for the surface potential to be reduced to half (+ 300V) by exposing the monochromatic light of 5 seconds to sensitivity E_1/2(ΜJ / cm²), And the surface potential 5 seconds after exposure is expressed as residual potential V_rObtained as (V).
The evaluation results are shown in Table 1 below.
[0057]
[Table 1]

[0058]
A drum-shaped photoconductor (30 mmφ) was used as an evaluation of durability by actual printing. Each drum-shaped photoconductor was mounted on a laser printer HL-1240 manufactured by Brother Industries, Ltd., and a black solid image, a white solid image, and a halftone image were printed in an environment of a temperature of 22 ° C. and a humidity of 44%. Subsequently, 5,000 images with a printing rate of about 5% were printed, and then a black solid image, a white solid image, and a halftone image were printed again, and image evaluation after printing 5,000 sheets was performed.
[0059]
As a result, in the photoreceptors of Examples 1 to 8, good images were obtained in both the initial image and the image after 5,000 sheets.
[0060]
In addition, it was found that the photoconductor Example 8 does not have sufficient sensitivity in the laser wavelength region (around 780 nm) of the used laser printer and is not suitable for this laser printer.
[0061]
【The invention's effect】
As described above, according to the present invention, a compound excellent in electron transportability can be obtained, and by applying this compound to an electronic device using an organic compound such as an electrophotographic photoreceptor, It becomes possible to improve electrical characteristics and the like. Further, according to the present invention, by using this compound as a charge transport material in a photosensitive layer provided on a conductive substrate, it is possible to obtain a photoreceptor having high sensitivity and excellent electrical characteristics in positive charging. became. The charge generation material can be selected according to the type of exposure light source. By using a phthalocyanine compound, a squarylium compound, a bisazo compound, etc., a photoconductor that can be used in a semiconductor laser printer or a copying machine can be obtained. Obtainable. Furthermore, it is possible to improve durability by installing a coating layer on the surface as necessary.
[Brief description of the drawings]
FIG. 1 is a conceptual cross-sectional view showing a single-layer electrophotographic photoreceptor.
FIG. 2 is a conceptual cross-sectional view showing a laminated electrophotographic photoreceptor.
FIG. 3 is an IR spectrum of a compound represented by a structural formula (I-2).
FIG. 4 shows a compound represented by the structural formula (I-2).¹It is a 1 H-NMR spectrum.
FIG. 5 is an IR spectrum of a compound represented by a structural formula (I-7).
FIG. 6 shows a structure of a compound represented by structural formula (I-7).¹It is a 1 H-NMR spectrum.
[Explanation of symbols]
1 Conductive substrate
2 Photosensitive layer
3 Charge generation layer
4 Charge transport layer
5 Photosensitive layer (lamination)
6 Coating layer

Claims (4)

The following general formula (I),

(In formula (I), R ¹ , R ² , R ³ and R ⁴ are the same or different and each has a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or a substituent. R ⁵ , R ⁶ and R ⁷ may be the same or different and each may have a substituent, an alkyl group having 1 to 12 carbon atoms, or an aryl which may have a substituent Represents a heterocyclic group which may have a group or a substituent, m represents an integer of 0 to 4, and the substituent is a halogen atom, a nitro group, an alkyl group having 1 to 6 carbon atoms, an aryl group, carbon A novel quinone compound having a structure represented by a halogenated alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. In the electrophotographic photoreceptor in which a photosensitive layer containing a charge generation material and a charge transport material is provided on a conductive substrate, the photosensitive layer has the following general formula (I),

(In formula (I), R ¹ , R ² , R ³ and R ⁴ are the same or different and each has a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or a substituent. R ⁵ , R ⁶ and R ⁷ may be the same or different and each may have a substituent, an alkyl group having 1 to 12 carbon atoms, or an aryl which may have a substituent Represents a heterocyclic group which may have a group or a substituent, m represents an integer of 0 to 4, and the substituent is a halogen atom, a nitro group, an alkyl group having 1 to 6 carbon atoms, an aryl group, carbon An electrophotographic photoreceptor comprising at least one compound represented by formula (1) represents a halogenated alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. The electrophotographic photoreceptor according to claim 2, wherein the photosensitive layer is a single-layer type photosensitive layer. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 2 and performing a charging process by a positive charging process.

Images