JP2004258337A - Electrophotographic photoreceptor, process cartridge, and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of producing a ghost-free image while retaining high sensitivity as an excellent electrophotographic property, free of occurrence of white streaks and black streaks due to unevenness in electrostatic charge, having a long printing durability life, and capable of stably producing a high-quality image, and to provide a process cartridge with the electrophotographic photoreceptor and an electrophotographic apparatus. <P>SOLUTION: Capacitance C per 1 cm<SP>2</SP>of the electrophotographic photoreceptor is ≥130 pF, and an intermediate layer of the electrophotographic photoreceptor contains polyamide resin and a titanium compound having a specified structure, wherein the ratio (mass ratio) of the polyamide resin to the titanium compound is 1/99 to 45/55. Alternatively, the intermediate layer contains a polyamide resin and a polymer obtained by polymerizing a titanium alkoxide and a compound having a specified structure, wherein the ratio (mass ratio) of the polyamide resin to the polymer is 1/99 to 45/55. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３４】
（式（１）中、Ｒ^１１は水素原子またはアルキル基を示し、ｍは１以上の整数であり、ｍが２以上の場合は、Ｒ^１１は同一であっても異なってもよい。Ｌは、１価の有機基を示し、ｎは１以上の整数であり、ｎが２以上の場合は、Ｌは同一であっても異なってもよい。）
（ＩＩ） ポリアミド樹脂と、チタニウムアルコキサイドおよび下記式（２）で示される構造を有する化合物を重合して得られる重合体とを含有し、該ポリアミド樹脂の該重合体に対する比（質量比）の値が１／９９〜４５／５５である層
【外５】

【００３５】
（式（２）中、Ｒ^２１、Ｒ^２３は、それぞれ独立に、アルキル基、水酸基またはアルコキシ基を示す。Ｒ^２２はアルキレン基を示す。）
また、本発明は、上記電子写真感光体を有するプロセスカートリッジおよび電子写真装置である。
【００３６】
【発明の実施の形態】
以下、本発明をより詳細に説明する。
【００３７】
まず、本発明に用いられる電子写真感光体の構成について説明する。
【００３８】
本発明の電子写真感光体は、支持体上に中間層、電荷発生物質を含有する電荷発生層、および、電荷輸送物質を含有する電荷輸送層とをこの順に積層した構成である。
【００３９】
支持体としては、導電性を有するものであればよく、アルミニウム、アルミニウム合金などが挙げられ、または、それらの上に導電性金属酸化物および結着樹脂を含有する導電性被膜を有させてもよい。
【００４０】
近年、露光光としてレーザービームを利用したプリンターの開発が盛んに行われているが、支持体表面が平滑面である場合、レーザー光の干渉といわれる現象を生じ、出力画像上にいわゆる干渉縞が発生する。この干渉縞を防止するために、各種の技術が検討されているが、最も有効な技術の１つとして、ホーニング処理などによって支持体表面を粗面化する方法が挙げられる。また、粗面化によって支持体の表面積が増加し、中間層との間に充分な接着強度が得やすく、良好な耐久性能も得られる。中間層の結着樹脂量を変化させることで支持体と中間層との密着性はコントロールできるが、干渉縞を防止するためには支持体が粗面化されていることが好ましく、表面が粗面化された支持体を用いることで、白抜けやゴーストなどが発生せず画像品質を維持したまま干渉縞の発生を抑制できる。
【００４１】
ホーニング処理としては、乾式または湿式での処理方法が挙げられるが、どちらを採用してもよい。
【００４２】
湿式ホーニング処理は、水などの液体に粉末状の研磨剤を懸濁させ、高速度で支持体表面に吹き付けて粗面化する方法であり、表面粗さは吹き付け圧力、速度、研磨剤の量、種類、形状、大きさ、硬度、比重および懸濁温度などにより制御することができる。
【００４３】
乾式ホーニング処理は、研磨剤をエアーにより、高速度で支持体表面に吹き付けて粗面化する方法であり、湿式ホーニング処理と同じように表面粗さを制御することができる。
【００４４】
湿式または乾式ホーニング処理に用いる研磨剤としては、炭化ケイ素、アルミナ、鉄、ガラスビーズなどの粒子が挙げられる。
【００４５】
導電性金属酸化物および結着樹脂を含有する導電性被膜を、アルミニウムやアルミニウム合金上に形成して支持体とする方法では、導電性被膜中にはフィラーとして、導電性微粒子を含有することが好ましい。この方法では、導電性微粒子を導電性被膜中に分散させることでレーザー光を乱反射させて干渉縞を防ぐと共に、塗布前の支持体の傷や突起などを隠蔽する効果もある。
【００４６】
導電性微粒子としては、酸化チタン、硫酸バリウムなどが挙げられ、必要によってはこれらの微粒子に酸化スズなどで導電性被覆層を設けることにより、フィラーとして適切な比抵抗とすることができる。導電性微粒子の粉体比抵抗は０．１〜１０００Ω・ｃｍが好ましく、さらには１〜１０００Ω・ｃｍがより好ましい。
【００４７】
本発明において、粉体比抵抗は、三菱化学（株）製の抵抗測定装置ロレスタＡＰ（Ｌｏｒｅｓｔａ Ａｐ）を用いて測定した。測定対象の粉体は、５００ｋｇ／ｃｍ^２の圧力で固めてコイン状のサンプルとして上記測定装置に装着した。微粒子の平均粒径は０．０５〜１．０μｍが好ましく、さらには０．０７〜０．７μｍがより好ましい。本発明において、微粒子の平均粒径は、遠心沈降法により測定した値である。
【００４８】
導電性被膜中のフィラーの含有量は、導電性被膜全質量に対して１．０〜９０重量％が好ましく、さらには５．０〜８０重量％がより好ましい。導電性被膜には、必要に応じてフッ素あるいはアンチモンを含有してもよい。
【００４９】
支持体の導電性被膜に用いられる結着樹脂としては、フェノール樹脂、ポリウレタン、ポリアミド、ポリイミド、ポリアミドイミド、ポリアミド酸、ポリビニールアセタール、エポキシ樹脂、アクリル樹脂、メラミン樹脂、ポリエステルなどが好ましい。これらの樹脂は、単独でも、２種以上を組み合わせて用いてもよい。上記樹脂は、支持体に対する接着性が良好であると共に、上記フィラーの分散性を向上させ、かつ、成膜後の耐溶剤性が良好である。上記樹脂の中でも特にフェノール樹脂、ポリウレタンおよびポリアミド酸がより好ましい。
【００５０】
導電性被膜は、例えば、浸漬あるいはマイヤーバーなどによる溶剤塗布で形成することができる。導電性被膜の膜厚は０．１〜３０μｍが好ましく、さらには０．５〜２０μｍがより好ましい。また、導電性被膜の体積抵抗率は、１０^１３Ω・ｃｍ以下、さらには１０^１０〜１０^１２Ω・ｃｍが好ましい。
【００５１】
本発明において、体積抵抗率は、アルミニウム板上に測定対象の導電性被膜を塗布し、さらにこの被膜上に金の薄膜を形成して、アルミニウム板と金薄膜の両電極間を流れる電流値をｐＡメーターで測定して求めた。
【００５２】
導電性被膜には、導電性微粒子以外に、酸化亜鉛や酸化チタンなどのフィラーを含有してもよい。さらに、表面性を高めるためにレベリング剤を添加してもよい。
【００５３】
本発明の電子写真感光体の中間層は、上述のとおり、下記（Ｉ）または（ＩＩ）で示される層である。
（Ｉ） ポリアミド樹脂と、下記式（１）で示される構造を有するチタニウム化合物を含有し、該ポリアミド樹脂の該チタニウム化合物に対する比（質量比）の値が１／９９〜４５／５５である層
【外６】

【００５４】
（式（１）中、Ｒ^１１は水素原子またはアルキル基を示し、ｍは１以上の整数であり、ｍが２以上の場合は、Ｒ^１１は同一であっても異なってもよい。Ｌは、１価の有機基を示し、ｎは１以上の整数であり、ｎが２以上の場合は、Ｌは同一であっても異なってもよい。）
上記式（１）中のＲ^１１のアルキル基としては、メチル基、エチル基、ｎ−プロピル基、ブチル基などが挙げられる。
【００５５】
また、上記式（１）中のＬの１価の有機基としては、アセチルアセトン、２，４−ヘプタンジオンなどのβ−ジケトン類や、アセト酢酸メチル、アセト酢酸エチル、アセト酢酸プロピル、アセト酢酸ブチルなどのケトエステル類や、乳酸、酢酸、サリチル酸、リンゴ酸などのヒドロキシカルボン酸類や、乳酸メチル、乳酸エチル、サリチル酸エチル、リンゴ酸エチルなどのヒドロキシカルボン酸エステル類や、ジエチレングリコール、オクタンジオール、ヘキサンジオールなどのグリコール類や、４−ヒドロキシ−４−メチル−２−ペンタノンなどのケトアルコール類から水素や水酸基を１つ取った１価の基が挙げられる。例えば、カルボン酸基を持つ酢酸などはエステル結合でチタンと結合し、β−ジケトンなどはチタンと共有結合および配位結合でキレート化合物の状態になっていると考えられる。
【００５６】
上記式（１）で示される構造を有するチタニウム化合物の具体的な例としては、チタニウム−トリ−ｎ−ブトキサイドペンタンジオネート、チタニウム−ジ−ｎ−ブトキサイド（ビス−２，４−ペンタンジオネート）、チタニウム−トリイソプロポキサイドペンタンジオネート、チタニウム−ジイソプロポサイド（ビス−２，４−ペンタンジオネート）、チタニウム−トリｎ−ブトキサイドエチルアセトアセテート、チタニウム−ジ−ｎ−ブトキサイド（ビスエチルアセトアセテート）、チタニウム−トリ−ｎ−ブトキサイドメチルアセトアセテート、チタニウム−ジ−ｎ−ブトキサイド（ビスメチルアセトアセテート）、チタニウム−ジイソプロポキサイド−ビス（２，２，６，６，−テトラメチル−３，５，−ヘプタンジオネート）、チタニウム−ビス（トリエタノールアミン）−ジ−ｎ−ブトキサイド、チタニウムラクテート、メタクリレートチタニウムブトキサイド、ステアリレートチタニウムブトキサイド、イソステアレートチタニウムブトキサイドなどが挙げられる。
（ＩＩ） ポリアミド樹脂と、チタニウムアルコキサイドおよび下記式（２）で示される構造を有する化合物を重合して得られる重合体とを含有し、該ポリアミド樹脂の該重合体に対する比（質量比）の値が１／９９〜４５／５５である層
【外７】

【００５７】
（式（２）中、Ｒ^２１、Ｒ^２３は、それぞれ独立に、アルキル基、水酸基またはアルコキシ基を示す。Ｒ^２２はアルキレン基を示す。）
上記チタニウムアルコキサイドとしては、チタニウムブトキサイド、チタニウムプロポキサイド、チタニウムエトキサイドなどが挙げられる。
【００５８】
また、上記式（２）中のＲ^２１、Ｒ^２３のアルキル基としては、メチル基、エチル基、ｎ−プロピル基、ブチル基などが挙げられ、アルコキシ基としては、メトキシ基、エトキシ基、プロポキシ基、ブトキシ基などが挙げられる。Ｒ^２２のアルキレン基としては、メチン基、エチン基、プロピン基、ブチン基などが挙げられる。
【００５９】
そして、上記式（１）で示される構造を有するチタニウム化合物、または、チタニウムアルコキサイドおよび上記式（２）で示される構造を有する化合物を重合して得られる重合体と組み合わせて用いられるポリアミド樹脂としては、いかなるものでもよいが、溶解性、体積抵抗率の環境変動などの点から、ナイロン６−６６−６１０−１２の４元ナイロン共重合体およびＮ−メトキシメチル化ナイロンが好ましい。ポリアミド樹脂は単一種でも、２種以上を組み合わせて用いてもよい。
【００６０】
ポリアミド樹脂の上記チタニウム化合物または上記重合体に対する比（質量比）の値は、１／９９〜４５／５５でなければならず、好ましくは２／９８〜３０／７０である。ポリアミド樹脂の割合が大きすぎると、ポリアミド樹脂の吸湿性の影響が大きくなり、環境変動に対して電子写真特性が大きく依存してしまうと共に、ポジゴーストが発生し、逆に、チタニウム化合物の割合が大きすぎると、塗工時にムラが生じやすく、支持体と中間層との密着性も低下してしまう。
【００６１】
このような中間層を採用することで、カブリ、黒ポチなどの画像特性、密着性が良好であり、さらには高感度で電荷発生量の多いフタロシアニンを用いてもゴーストが発生しない電子写真感光体を提供することができる。
【００６２】
中間層上には電荷発生層が形成される。
【００６３】
本発明の電子写真感光体に用いられる電荷発生物質はフタロシアニン顔料であり、具体的には、無金属フタロシアニンや、中心金属として、銅塩化インジウム、塩化ガリウム、オキシチタニウム、亜鉛、バナジウムなどを有するフタロシアニン顔料が挙げられる。これらの中でも電子写真特性、画質の点で、無金属フタロシアニンや、オキシチタニウムフタロシアニンや、ヒドロキシガリウムフタロシアニンや、クロロガリウムフタロシアニンなどのハロゲン化ガリウムフタロシアニンが好ましく、特にはオキシチタニウムフタロシアニンおよびヒドロキシガリウムフタロシアニンが好ましい。
【００６４】
電荷発生層には、フタロシアニン顔料以外の電荷発生物質を含有させることも可能である。例えば、セレン−テルル、ピリリウム、チアピリリウム染料、アントアントロン、ジベンズピレンキノン、トリスアゾ、シアニン、ジスアゾ、モノアゾ、インジゴ、キナクリドンおよび非対称キノシアニンの各顔料などが挙げられる。
【００６５】
電荷発生層は、上記電荷発生物質を０．３〜４倍量（質量比）の結着樹脂および溶剤とともにホモジナイザー、超音波分散、ボールミル、振動ボールミル、サンドミル、アトライター、ロールミルまたは液衝突型高速分散機などを使用して十分に分散し、分散液を塗布、乾燥させて形成される。
【００６６】
電荷発生層の膜厚は５μｍ以下が好ましく、さらには０．１〜２μｍがより好ましい。
【００６７】
電荷発生層上には電荷輸送層が形成される。
【００６８】
電荷輸送層は、主として電荷輸送物質と結着樹脂とを溶剤中に溶解させた塗料を塗布、乾燥して形成する。用いられる電荷輸送物質としては、トリアリールアミン化合物、ヒドラゾン化合物、スチルベン化合物、ピラゾリン化合物、オキサゾール化合物、トリアリルメタン化合物およびチアゾール化合物などが挙げられる。
【００６９】
電荷輸送層は、上記電荷輸送物質と、その０．５〜２倍量（質量比）の結着樹脂とを溶解させた塗布液を塗布、乾燥させて形成される。
【００７０】
電荷輸送層の結着樹脂としては、下記式（３）で示される繰り返し構造単位を有するポリアリレート樹脂を単独で、
【外８】

【００７１】
（式（３）中、Ｘ^３１は、炭素原子または単結合を示す（単結合の場合、Ｒ^３５およびＲ^３６は無し）。Ｒ^３１〜Ｒ^３４は、それぞれ独立に、水素原子、ハロゲン原子、置換または無置換のアルキル基、または、置換または無置換のアリール基を示す。Ｒ^３５、Ｒ^３６は、それぞれ独立に、水素原子、ハロゲン原子、置換または無置換のアルキル基、置換または無置換のアリール基、または、Ｒ^３５とＲ^３６とが結合することによって形成されるアルキリデン基を示す。Ｒ^３７〜Ｒ^４０は、それぞれ独立に、水素原子、ハロゲン原子、置換または無置換のアルキル基、または、置換または無置換のアリール基を示す。）
あるいは、その他の構造のポリアリレート樹脂、ポリカーボネート樹脂、ポリエステル樹脂、ポリメタクリル酸エステル、ポリスチレン樹脂、アクリル樹脂、ポリアミド樹脂などの樹脂、ポリ−Ｎ−ビニルカルバゾール、ポリビニルアントラセンなどの有機光導電性ポリマーなどと混合して用いてもよい。
【００７２】
上記式（３）で示される繰り返し構造単位の具体例を以下に示すが、本発明はこれらに限られるものではない。
【００７３】
【外９】

【００７４】
【外１０】

【００７５】
【外１１】

【００７６】
【外１２】

【００７７】
【外１３】

【００７８】
本発明の電子写真感光体においては、上記式（３）で示される繰り返し構造単位が単一のもので構成される単独重合体でも、２種類以上の繰り返し構造単位で構成される共重合体でもよい。
【００７９】
なお、本発明においては、上記式（３）で示される繰り返し構造単位を有するポリアリレートの粘度平均分子量は１０，０００〜２００，０００であることが好ましく、さらには１５，０００〜１００，０００であることがより好ましい。
【００８０】
また、本発明の電子写真感光体の電荷輸送層の膜厚は９〜１８μｍである。電荷輸送層の膜厚が９μｍより薄い場合、電子写真感光体の帯電能が十分でなく、１８μｍより厚い場合には、帯電安定性が低下して帯電ムラが発生する。
【００８１】
また、ゴースト現象の発生をより抑制するためには、電子写真感光体にかかる電界強度を３．３×１０^５〜８．１×１０^５Ｖ／ｃｍとすることが好ましい。
【００８２】
電子写真感光体に接触配置した接触帯電部材によって該電子写真感光体を帯電する接触帯電方式は、電子写真感光体と接触帯電部材との接触部近傍の微小空間において、パッシェン則にしたがう空隙破壊放電によって行われる。
【００８３】
一般的な電子写真装置では、電子写真感光体にドラム形状またはベルト形状のものを用いるが、どちらの形状のものでも接触帯電部材に対して回転または移動させながら帯電させている。すなわち、電子写真感光体と接触帯電部材との接触部を境界として、電子写真感光体は上流側と下流側とに分けられ、各々の上流側または下流側の両微小空間で帯電が行われる。このとき、パッシェン則にしたがう空隙破壊放電がなされるが、このような帯電メカニズムの性格上、電子写真感光体の比誘電率、膜厚（静電容量）、帯電部材の抵抗値、印加電圧などの多数の要因が関与して均一に帯電させることは容易でない。その対策の１つとして、上述したとおり、交流電圧を重畳した脈流電圧によって印加する方法が提案されている。
【００８４】
本発明の電子写真感光体は、その帯電に、直流電圧のみを印加する方式（ＤＣ帯電方式）を採用しても、電子写真感光体の１ｃｍ^２当りの静電容量Ｃを１３０ｐＦ以上にすることにより、脈流電圧によって印加した場合と同様に均一に帯電できる。
【００８５】
すなわち、電子写真感光体の１ｃｍ^２当りの静電容量Ｃが１３０ｐＦ以上にすることにより、スジ画像などの原因であると考えられる逆方向の電場の生成を安定に抑制でき、全体としての帯電特性は脈流電圧によって印加した場合と同様に、スジ画像などがない均一な帯電を行うことができたと考えられる。交流電圧の重畳は行わなければ、上述した交流電圧の重畳を重畳した際の技術課題も発生しない。
【００８６】
なお、本発明においては、帯電手段の帯電能力の観点から、電子写真感光体の１ｃｍ^２当りの静電容量Ｃは５００ｐＦ以下であることが好ましく、さらには３５０ｐＦ以下であることがより好ましい。
【００８７】
さらに、本発明では、電荷輸送層が電子写真感光体の表面層である場合、電荷輸送層の結着樹脂としてポリアリレート樹脂を用いることにより、電子写真感光体の機械的強度が向上すると共に、帯電方式をＤＣ帯電方式とすれば、帯電による電子写真感光体のダメージも減るため、電子写真感光体の機械的摩耗が非常に少なくなり、電荷輸送層の膜厚が９〜１８μｍであっても、電子写真感光体の寿命を犠牲にすることなく、ＤＣ帯電の帯電均一性を格段に向上させることが可能になる。
【００８８】
次に、図１を参照しながら、本発明の電子写真装置の概略構成を説明する。ただし、図１に示す電子写真装置の概略構成は一例であり、本発明はこれに限定されるものではない。
【００８９】
図１に示す装置は、ドラム形状の電子写真感光体２６（例えば、直径３０ｍｍの感光ドラム）に接触配置された帯電手段２１である帯電ローラーにより電子写真感光体を直流電圧のみにより一様に帯電する。
【００９０】
帯電に次いで、露光手段（不図示）からのレーザー光で画像部分を露光することにより静電潜像を形成し、現像手段２２により可視画像（トナー画像）とした後、電圧を印加した転写手段（転写ローラー）２７により、該トナー画像を転写材２８に転写する。２３は規制ブレードであり、２４は現像ローラーであり、２５は供給ローラーである。
【００９１】
像転写後の電子写真感光体２６の表面は、クリーニングブレード２９を有するクリーニング手段３０によって転写残りトナーの除去を受けて清浄面化された後、繰り返し画像形成に使用される。
【００９２】
なお、本発明の電子写真装置においては、前露光手段からの前露光光による電子写真感光体表面の除電処理を行う必要は必ずしもない。
【００９３】
また、電子写真感光体２６と、帯電手段２１、現像手段２２、転写手段２７およびクリーニング手段３０の少なくとも１つの手段とを一体に支持し、電子写真装置本体に着脱自在のプロセスカートリッジとすることもできる
【００９４】
【実施例】
以下、実施例および比較例により、本発明をさらに詳細に説明するが、本発明はこれらの実施例などに限定されるものではない。
【００９５】
なお、実施例中の「部」は「質量部」を意味する。
【００９６】
＜電子写真感光体製造例１＞
熱間押し出しにより得たＡ３００３の外径３０．５ｍｍ、内径２８．５ｍｍ、長さ２６０．５ｍｍアルミニウム素管（ＥＤ管）を、支持体として準備した。
【００９７】
次に、液体（湿式）ホーニング装置（（株）不二精機製造所製）を用いて、下記条件にて液体ホーニング処理を行った。
・液体ホーニング条件
研磨材砥粒：平均粒径３０μｍの球状アルミナビーズ（商品名：ＣＢ−Ａ３０Ｓ、昭和電工（株）製）
懸濁媒体：水、
研磨材／懸濁媒体：１／９（体積比）
アルミニウム切削管の回転数：１．６７ｓ^−１
エアー吹き付け圧力：０．１６５ＭＰａ
ガン移動速度：１３．３ｍｍ／ｓ
ガンノズルとアルミニウム管の距離：１８０ｍｍ
ホーニング砥粒吐出角度：４５°
研磨液投射回数：１回
表面粗さの測定は、ＪＩＳＢ０６０１に準じ、（株）小坂研究所製の表面粗さ計サーフコーダーＳＥ３５００を用い、カットオフを０．８ｍｍ、測定長さを８ｍｍで行った。ホーニング後の支持体表面粗さは、Ｒｍａｘ＝３．０μｍ、Ｒｚ＝１．５５μｍ、Ｒａ＝０．２４μｍ、Ｓｍ＝３４μｍであった。
【００９８】
次に、メトキシエタノール１６０部にチタニウム−テトラ−ｎ−ブトキサイドの８５％ブタノール溶液（関東化学（株）製）９０部を滴下し、メトキシエタノール１６０部／水１１部の混合溶液をさらに加えた。
【００９９】
上記式（２）で示される構造を有する化合物としてアセチルアセトン２０部をメタノール２００部に加えた溶液を、上記チタニウム−テトラ−ｎ−ブトキサイドと水との混合溶液に滴下した後、ポリアミド樹脂としてナイロン６−６６−６１０−１２の４元ナイロン共重合体（商品名：アミランＣＭ８０００、東レ（株）製）の１０質量％メタノール液８５部とを混合して得た中間層塗布液を上記支持体上に浸漬塗布し、１５０℃で２０分加熱して、膜厚０．３μｍの中間層を形成した。
【０１００】
次に、ＣｕＫαの特性Ｘ線回折におけるブラッグ角（２θ±０．２°）の９．０°、１４．２°、２３．９°および２７．１°に強いピークを有するオキシチタニウムフタロシアニン４部、ポリビニルブチラール（商品名：エスレックＢＭ２積水化学製）２部およびシクロヘキサノン６０部を、直径１ｍｍのガラスビーズを用いたサンドミル装置で４時間分散した後、エチルアセテート１００部を加えて電荷発生層用分散液を調製した。これを浸漬塗布法で上記中間層上に塗布し、乾燥して、膜厚０．３μｍの電荷発生層を形成した。
【０１０１】
次に、電荷輸送層を形成するために、電荷輸送層用の塗料を調製した。
【０１０２】
結着樹脂として上記式（３−２）で示される繰り返し構造単位を有するポリアリレート樹脂１０部と、下記式（Ａ）で示される構造を有するアミン化合物９部、
【外１４】

【０１０３】
下記式（Ｂ）で示される構造を有するアミン化合物１部を、
【外１５】

【０１０４】
モノクロロベンゼン５０部／ジクロロメタン５０部の混合溶媒に溶解した。この塗料を浸漬塗布法で上記電荷発生層上に塗布し、１２０℃で２時間乾燥し、膜厚９μｍの電荷輸送層を形成した。
【０１０５】
このようにして電子写真感光体１を作製した。
【０１０６】
＜電子写真感光体製造例２＞
電子写真感光体製造例１において、電荷輸送層の膜厚を１４μｍとした以外は、電子写真感光体製造例１と同様にして電子写真感光体２を作製した。
【０１０７】
＜電子写真感光体製造例３＞
電子写真感光体製造例１において、電荷輸送層の膜厚を１８μｍとした以外は、電子写真感光体製造例１と同様にして電子写真感光体３を作製した。
【０１０８】
＜電子写真感光体製造例４＞
電子写真感光体製造例１において、電荷輸送層の膜厚を２０μｍとした以外は、電子写真感光体製造例１と同様にして電子写真感光体４を作製した。
【０１０９】
＜電子写真感光体製造例５＞
電子写真感光体製造例１において、電荷輸送層の膜厚を２５μｍとした以外は、電子写真感光体製造例１と同様にして電子写真感光体５を作製した。
【０１１０】
（実施例１〜３および比較例１、２）
電子写真感光体１〜５を表１に示すように用いて、図１に示す構成を有するヒューレットパッカード製ＬＢＰ「レーザージェット４０００」（プロセススピード９４．２ｍｍ／ｓ）をＤＣ帯電に改造し、以下のプロセス条件を設定して評価を行った。
【０１１１】
電子写真感光体暗部電位：−６００Ｖ
電子写真感光体明部電位：−１５０Ｖ
現像バイアス：−３５０Ｖ（直流電圧のみ）
１５℃／１０％ＲＨの環境下で初期画像評価を行った。画像の評価は以下のように行った。
【０１１２】
プリント画像書き出しから電子写真感光体１回転の部分に２５ｍｍ角の正方形のベタ黒部を並べ、電子写真感光体２回転目以降に１ドットを桂馬パターンで印字したハーフトーンのテストチャートでゴーストを評価した。
【０１１３】
また、プリント全面に１ドットを桂馬パターンで印字したハーフトーンのテストチャートおよびベタ黒画像により帯電ムラによるスジ画像の評価を行った。
【０１１４】
評価結果を表１に示す。
【０１１５】
なお、本発明における静電容量Ｃは、図２に示した静電容量測定装置を用いて、以下の手順によって求めた。
【０１１６】
１．静電容量（Ｃ_Ｘ）を測定したいサンプル（電子写真感光体）と、静電容量既知（Ｃ_０）のコンデンサー４６を図２のように接続して、所定の直流電圧が印加されたコロナ帯電器４１でサンプル（電子写真感光体）４４を帯電させた。
【０１１７】
２．スイッチＳＷをＯＦＦの状態にして、表面電位計４２でサンプル（電子写真感光体）４４の表面電位を測定した。このときの測定値をＶ_１とした。
【０１１８】
３．次にスイッチＳＷをＯＮの状態にして、再び表面電位計４２でサンプル（電子写真感光体）４４の表面電位を測定した。このときの測定値をＶ_２とした。
【０１１９】
４．静電容量Ｃ_Ｘの計算方法は以下のとおりである。
【０１２０】
Ｖ_１＝Ｖ_０＋Ｖ_Ｘ＝ｑ／Ｃ_０＋ｑ／Ｃ_Ｘ・・・（１）
Ｖ_２＝Ｖ_Ｘ＝ｑ／Ｃ_Ｘ・・・（２）
上記（１）、（２）式よりｑを消去すると
Ｃ_Ｘ＝［（Ｖ_１−Ｖ_２）／Ｖ_２］・Ｃ_０
となる。そして、測定された静電容量Ｃ_Ｘをサンプル（電子写真感光体）の表面積で割ることにより、単位面積あたりの静電容量が求められる。
【０１２１】
図２中、４３は電荷であり、４５は電極である。
【０１２２】
【表１】

【０１２３】
＜電子写真感光体製造例６＞
熱間押し出しにより得たＡ３００３の外径３０．５ｍｍ、内径２８．５ｍｍ、長さ２６０．５ｍｍアルミニウム素管（ＥＤ管）を準備した。
【０１２４】
酸化スズで形成された被覆層を有する硫酸バリウム微粒子（被覆率５０重量％、粉体比抵抗７００Ω・ｃｍ）１２０部と、レゾール型フェノール樹脂（商品名：プライオーフェンＪ−３２５、大日本インキ化学工業（株）製、固形分７０％）７０部と、２−メトキシ−１−プロパノ−ル１００部とからなる溶液を、２０時間ボールミルで分散し、導電性被膜用塗布液を調製した（この塗布液に含有するフィラーの平均粒径は０．２２μｍであった）。この塗布液を浸漬塗布法によって上記アルミニウム素管上に塗布し、１４０℃で３０分間加熱硬化することにより、膜厚１５μｍの導電性被膜を形成し、これを支持体とした。
【０１２５】
次に、メトキシエタノール１６０部にチタニウム−テトラ−ｎ−ブトキサイドの８５％ブタノール溶液（関東化学（株）製）９０部を滴下し、メトキシエタノール１６０部／水１１部の混合溶液をさらに加えた。
【０１２６】
上記式（２）で示される構造を有する化合物としてアセチルアセトン２０部をメタノール２００部に加えた溶液を、上記チタニウム−テトラ−ｎ−ブトキサイドと水との混合溶液に滴下した後、ポリアミド樹脂としてナイロン６−６６−６１０−１２の４元ナイロン共重合体（商品名：アミランＣＭ８０００、東レ（株）製）の１０質量％メタノール液７．７部とを混合して得た中間層塗布液を上記支持体上に浸漬塗布し、１５０℃で２０分加熱して、膜厚０．３μｍの中間層を形成した。
【０１２７】
次に、ＣｕＫαの特性Ｘ線回折におけるブラッグ角（２θ±０．２°）の７．４°および２８．２°に強いピークを有するヒドロキシガリウムフタロシアニン結晶２部、ポリビニルブチラール（商品名：エスレックＢＭ２、積水化学（株）製）１部およびシクロヘキサノン６０部を、直径１ｍｍのガラスビーズを用いたサンドミル装置で３時間分散した後、シクロヘキサノン５０部と酢酸エチル１３０部を加えて希釈し、電荷発生層用塗料を調製した。これを浸漬塗布法で上記中間層上に塗布し、１００℃で１０分間乾燥して、膜厚０．２μｍの電荷発生層を形成した。
【０１２８】
電荷輸送層は電子写真感光体製造例２と同様にして形成した。
【０１２９】
このようにして電子写真感光体６を作製した。
【０１３０】
＜電子写真感光体製造例７＞
電子写真感光体製造例６において、中間層塗布液のポリアミド樹脂溶液を８５部とした以外は、電子写真感光体製造例６と同様にして電子写真感光体７を作製した。
【０１３１】
＜電子写真感光体製造例８＞
電子写真感光体製造例６において、中間層を以下のように形成した以外は、電子写真感光体製造例６と同様にして電子写真感光体８を作製した。
【０１３２】
チタニウム−ジ−ｎ−ブトキサイド（ビス−２，４−ペンタンジオネート）の６０％ブタノール溶液１２８部、メトキシプロパノール１５０部を混合し、メトキシプロパノール１５０部／水１１部の混合溶液をさらに加えた。Ｎ−メトキシメチル化ナイロン（商品名：トレジンＥＦ−３０Ｔ、帝国化学産業（株）製）の１０質量％メタノール液３２５部をさらに混合して得た中間層塗布液を支持体上に浸漬塗布し、１５０℃で２０分加熱して、膜厚０．３μｍの中間層を形成した。
【０１３３】
＜電子写真感光体製造例９＞
電子写真感光体製造例８において、中間層塗布液のポリアミド樹脂溶液を６２５部とした以外は、電子写真感光体製造例８と同様にして電子写真感光体９を作製した。
【０１３４】
＜電子写真感光体製造例１０＞
電子写真感光体製造例６において、中間層にポリアミド樹脂を用いなかった以外は、電子写真感光体製造例６と同様にして電子写真感光体１０を作製した。
【０１３５】
＜電子写真感光体製造例１１＞
電子写真感光体製造例７において、中間層塗布液のチタニウム−テトラ−ｎ−ブトキサイドに代えて、チタニウムアセチルアセトネートを加え、アセチルアセトンを用いなかった以外は、電子写真感光体製造例７と同様にして中間層を形成したが、中間層の膜に細かいひび割れが生じたため、電子写真感光体を作製できなかった。
【０１３６】
＜電子写真感光体製造例１２＞
電子写真感光体製造例６において、中間層塗布液のポリアミド樹脂を１１５０部とした以外は、電子写真感光体製造例６と同様にして電子写真感光体１２を作製した。
【０１３７】
＜電子写真感光体製造例１３＞
電子写真感光体製造例７において、中間層塗布液の結着樹脂としてポリアミド樹脂の代わりにブチラール樹脂（エスレックスＢＭ−Ｓ、積水化学（株）製）を用いた以外は、電子写真感光体製造例７と同様にして電子写真感光体１３を作製した。
【０１３８】
（実施例４〜７および比較例３〜６）
電子写真感光体６〜１３を表２に示すように用いて、図１に示す構成を有するヒューレットパッカード製ＬＢＰ「レーザージェット４０００」（プロセススピード９４．２ｍｍ／ｓ）をＤＣ帯電に改造し、以下のプロセス条件を設定して評価を行った。
【０１３９】
電子写真感光体暗部電位：−６００Ｖ
電子写真感光体明部電位：−１５０Ｖ
現像バイアス：−３５０Ｖ（直流電圧のみ）
電子写真感光体の静電容量：１８５ｐＦ
電界強度４．２９×１０^５
１５℃／１０％ＲＨの環境下で初期画像評価を行った。画像の評価は以下のように行った。
【０１４０】
プリント画像書き出しから電子写真感光体１回転の部分に２５ｍｍ角の正方形のベタ黒部を並べ、電子写真感光体２回転目以降に１ドットを桂馬パターンで印字したハーフトーンのテストチャートでゴーストを評価した。
【０１４１】
また、プリント全面に１ドットを桂馬パターンで印字したハーフトーンのテストチャートおよびベタ黒画像により帯電ムラによるスジ画像の評価を行い、ベタ白画像により黒ポチ、カブリ評価を行った。
【０１４２】
次いで、Ａ４サイズ紙に面積比率４％印字の文字パターンで１５０００枚の連続画像出力試験を行い、画像評価を行った。
【０１４３】
評価結果を表２に示す。
【０１４４】
【表２】

【０１４５】
＜電子写真感光体製造例１４＞
電子写真感光体製造例２において、電荷発生層を以下のように形成した以外は、電子写真感光体製造例２と同様にして電子写真感光体１４を作製した。
【０１４６】
ＣｕＫαの特性Ｘ線回折におけるブラッグ角（２θ±０．２°）の７．４°および２８．２°に強いピークを有するヒドロキシガリウムフタロシアニン結晶２．５部、ポリビニルブチラール（商品名：エスレックＢＭ２、積水化学（株）製）１部およびシクロヘキサノン６０部を、直径１ｍｍのガラスビーズを用いたサンドミル装置で３時間分散した後、シクロヘキサノン５０部と酢酸エチル１３０部を加えて希釈し、電荷発生層用塗料を調製した。この電荷発生層用塗料を中間層上に浸漬塗布し、１００℃で１０分間乾燥して、膜厚０．２μｍの電荷発生層を形成した。
【０１４７】
＜電子写真感光体製造例１５＞
電子写真感光体製造例１４において、電荷輸送層の結着樹脂を上記式（３−２）で示される繰り返し構造単位と上記式（３−２４）で示される繰り返し構造単位を有する共重合体（共重合比５０：５０（モル比））のポリアリレート樹脂（重量平均分子量：９５０００）を用いた以外は、電子写真感光体製造例１４と同様にして電子写真感光体１５を作製した。
【０１４８】
＜電子写真感光体製造例１６＞
電子写真感光体製造例１４において、電荷輸送層の結着樹脂をビスフェノールＺ型ポリカーボネート（商品名：ユーピロンＺ−２００、三菱ガス化学（株）製）に代えた以外は、電子写真感光体製造例１４と同様にして電子写真感光体１６を作製した。
【０１４９】
（実施例８〜１１および比較例７〜９）
電子写真感光体１４〜１６を実施例１と同様にして評価した。ただし、電子写真感光体の暗部電位を表３に示すように変更して、電子写真感光体にかかる電界強度を変えた。
【０１５０】
次いで、Ａ４サイズ紙に面積比率４％印字の文字パターンで１５０００枚の連続画像出力試験を行い、画像評価を行った。
【０１５１】
評価結果を表３に示す。
【０１５２】
【表３】

【０１５３】
【発明の効果】
本発明によれば、支持体上に中間層、電荷発生層および電荷輸送層をこの順に有する電子写真感光体であって、該電荷発生層が電荷発生物質としてフタロシアニン顔料を含有し、該電荷輸送層の膜厚が９〜１８μｍである電子写真感光体であっても、優れた電子写真特性としての高感度を維持しつつ、ゴーストが発生しない画像を出力できる電子写真感光体、該電子写真感光体を有するプロセスカートリッジおよび電子写真装置を提供することができる。
【０１５４】
また、帯電の不均一性による白スジ・黒スジの発生がなく、耐印刷寿命が長く、高品質の画像を安定して出力できる電子写真感光体、該電子写真感光体を有するプロセスカートリッジおよび電子写真装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の電子写真感光体を有する電子写真装置の概略構成を示す図である。
【図２】静電容量測定装置の概略構成を示す図である。
【符号の説明】
２１ 帯電手段
２２ 現像手段
２３ 規制ブレード
２４ 現像ローラー
２５ 供給ローラー
２６ 電子写真感光体
２７ 転写手段
２８ 転写材
２９ クリーニングブレード
３０ クリーニング手段
４１ コロナ帯電器
４２ 表面電位計
４３ 電荷
４４ サンプル（静電容量未知Ｃ_Ｘ）
４５ 電極
４６ コンデンサー（静電容量既知Ｃ_０）
ＳＷ スイッチ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.
[0002]
[Prior art]
In recent years, from the viewpoint of low cost, high degree of freedom in designing an electrophotographic photoreceptor, and non-polluting properties, an organic electrophotographic photoreceptor employing an organic substance (organic photoconductive substance) as a photoconductive substance has been developed. Widely used.
[0003]
The organic photoconductive substance can freely select the photosensitive wavelength range of the electrophotographic photoreceptor depending on its type. For example, JP-A-61-272754 and JP-A-56-167759 disclose the same. An azo pigment having high sensitivity in the visible region is disclosed, and JP-A-57-19576 and JP-A-61-228453 disclose azo pigments having sensitivity up to the infrared region. I have.
[0004]
Among these photoconductive substances, those exhibiting sensitivity in the infrared region are used for laser beam printers (hereinafter abbreviated as LBPs) and LED printers for digitally forming an electrostatic latent image, and the demand frequency is high. Has become. As the direction of the technology of the LBP and the LED printer, the resolution has been increased from 240/300 dpi to 400/600/1200 dpi.
[0005]
In addition, the functions of the copiers are also becoming more sophisticated, and for this reason, they are rapidly moving toward digitalization. The mainstream of digital machines is a method of forming an electrostatic latent image with a laser, and has advanced in the direction of higher resolution as in the case of the printer.
[0006]
As an electrophotographic photoreceptor used for digitally forming an electrostatic latent image,
(1) that it can be charged to an appropriate potential in a dark place;
{Circle around (2)} Dissipation of electric charge in a dark place is small;
(3) that charge can be quickly dissipated by light irradiation;
And the like. In particular, regarding (3), it is necessary to have sensitivity to infrared light.
[0007]
Many phthalocyanine pigments have high sensitivity in the infrared region and are widely used in electrophotographic photoreceptors. In particular, in recent years, oxytitanium phthalocyanine has been widely used as a material having high sensitivity in the infrared region. JP-A-5-188615 discloses an electrophotographic photosensitive member using chlorogallium phthalocyanine, and JP-A-5-249716 discloses an electrophotographic photosensitive member using hydroxygallium phthalocyanine. .
[0008]
Electrophotographic photoreceptors employing these phthalocyanine pigments as charge generation materials in the charge generation layer are extremely sensitive and have sensitivity up to the infrared region, but the absolute number of carriers is high due to the high sensitivity. In many cases, electrons after holes have been injected tend to remain in the charge generation layer, and as a kind of memory, there is a drawback that potential fluctuations are likely to occur.
[0009]
In principle, it is considered that the electrons left in the charge generation layer proceed to the interface between the charge generation layer and the charge transport layer for some reason, and lower the barrier property of hole injection near the interface.
[0010]
As a specific phenomenon, there is a decrease in the bright portion potential and the residual potential during continuous printing. For example, when used in a development process (a so-called reversal development system) in which a dark potential portion is used as a non-development portion and a light potential portion is used as a development portion, which is often used in printers at present, the sensitivity at the place where light was applied during the previous printing is used. If a full black image is taken at the time of the next print, the so-called ghost phenomenon, in which the previous print portion appears black, appears remarkably.
[0011]
In particular, this phenomenon is remarkable in an electrophotographic photoreceptor using an intermediate layer or the like as an adhesive layer of the charge generation layer. In a low-temperature and low-humidity environment, the volume resistance of the charge generation layer and the intermediate layer to electrons increases, so that the electrons generate charge. There is a drawback that the layer is easily filled and a ghost phenomenon is easily generated.
[0012]
When a laminated electrophotographic photosensitive member containing a phthalocyanine pigment in the charge generation layer (an electrophotographic photosensitive member having a laminated photosensitive layer) is used in a reversal developing electrophotographic process, the above problem is potentially involved.
[0013]
Therefore, conventionally, the process of the first rotation of the electrophotographic photosensitive member in which the charging voltage is reduced is not used for image formation (idle rotation), and is used for image formation from the second rotation onward when the charging voltage is stabilized. At present, such a problem is avoided by performing charge elimination of the electrophotographic photosensitive member by exposure before charging. In printers with relatively slow print speeds, such development does not appear significantly because the charge control capability of the charger can be afforded, and it takes time to transfer data from a computer etc. Although there was no particular problem in the process of making the first rotation idle, the process of making the first rotation idle in the recent trend of increasing the printing speed and shortening the printout time has been difficult. There is a problem that speeding up is greatly hindered.
[0014]
In addition, when performing pre-charging exposure, it is necessary to sufficiently attenuate the charging potential, and the exposure amount needs to be several times to 20 times the image exposure amount. In addition, there is an adverse effect such as a large variation in the dark portion potential and the bright portion potential during continuous printing, and the development of an electrophotographic apparatus and an image forming method capable of forming an image from the first rotation of the laminated electrophotographic photosensitive member has been developed. Was requested.
[0015]
On the other hand, when an image is output by performing basic processes such as charging, exposure, development, transfer, fixing, and cleaning on an electrophotographic photoreceptor, conventionally, a charging process applies a high voltage (5 to 8 kV DC) to a metal wire. Charging was performed by the generated corona (corona charging method).
[0016]
However, in the corona charging method, the surface of the electrophotographic photoreceptor is deteriorated by corona products such as ozone and nitrogen oxides, causing image blurring and deterioration, and dirt on the wire affects image quality, resulting in image whiteout. And black streaks.
[0017]
In particular, organic electrophotographic photoreceptors that use organic photoconductive materials have poorer chemical stability than inorganic electrophotographic photoreceptors that use inorganic photoconductive materials such as selenium and amorphous silicon. When exposed, a chemical reaction (mainly an oxidation reaction) occurs and tends to deteriorate.
[0018]
Therefore, when the organic electrophotographic photoreceptor is repeatedly used under corona charging, image blurring due to the above-described deterioration and a low density due to a decrease in sensitivity occur more remarkably, and the life of printing (copying) becomes shorter. there were.
[0019]
In the corona charging method, the electric current flowing toward the electrophotographic photoreceptor is only 5 to 30% of the electric power, and most of the electric current flows to the shield plate, so that the charging means is inefficient.
[0020]
In order to compensate for such a problem, a contact charging system instead of a corona charging system is disclosed in, for example, JP-A-57-178267, JP-A-56-104351, and JP-A-58-40566. These are disclosed in, for example, JP-A-58-139156 and JP-A-58-150975.
[0021]
Specifically, the surface of the electrophotographic photosensitive member is charged to a predetermined potential by contacting a contact charging member such as a conductive elastic roller to which a DC voltage of about 1 to 2 kV is externally applied to the surface of the electrophotographic photosensitive member. Things.
[0022]
In particular, in recent years, the contact charging system has been mounted on many electrophotographic apparatuses and has become the mainstream of the charging method. Most of the methods employ a method of applying a voltage to a conductive roller.
[0023]
The contact charging system includes a system in which only a DC voltage is applied (DC charging system) and a system in which an AC voltage is superimposed on a DC voltage (AC / DC charging system). Most of the electrophotographic apparatuses use the latter method. Is used. The reasons for this include non-uniform charging and the occurrence of discharge breakdown of the electrophotographic photosensitive member due to direct application of a voltage.
[0024]
Due to the non-uniformity of charging, streaky charging unevenness having a length of about 2 to 200 mm and a width of about 0.5 mm or less occurs in a direction perpendicular to the moving direction of the charged surface. Image defects such as white streaks (phenomena in which white streaks appear in a solid black or halftone image) or black streaks that occur in a reversal development method.
[0025]
In order to solve such problems and improve the uniformity of charging, there has been proposed a method in which an AC voltage is superimposed on a DC voltage and applied to a contact charging member (JP-A-63-149668). Used.
[0026]
The AC / DC charging system performs uniform charging by superimposing an _AC voltage (V _AC ) on a DC voltage (V _DC ), that is, applying a pulsating voltage. In the case of this charging system, charging is performed. In order to maintain image uniformity and prevent image defects such as white spots in the forward development mode, black spots and fog in the reverse development mode, the superimposed AC voltage has a peak-to-peak potential difference (V _{P) that is at} least twice the DC voltage. _-P ) is preferred.
[0027]
However, when the superimposed AC voltage is increased in order to prevent image defects, discharge breakdown occurs at a small defect site in the electrophotographic photosensitive member due to the maximum applied voltage of the pulsating voltage. In particular, in the case of an organic electrophotographic photosensitive member having a low withstand voltage, this dielectric breakdown is remarkable. In this case, in the normal development system, the image is blank in the longitudinal direction of the contact portion, and in the reversal development system, black obscuration occurs. Furthermore, when there is a pinhole, there is a problem that a portion there serves as a conduction path, current leaks, and the voltage applied to the charging member drops.
[0028]
Furthermore, when an AC voltage is superimposed during charging, the discharge current during charging increases compared to when only a DC voltage is applied, and the durability of the electrophotographic photosensitive member increases, such as an increase in the amount of wear on the surface layer of the electrophotographic photosensitive member. In the case of an electrophotographic photoreceptor having a charge transport layer laminated on a charge generation layer, the lifetime is ensured by increasing the thickness of the charge transport layer.
[0029]
However, when the thickness of the charge transport layer is increased, the reproducibility of the electrostatic latent image is reduced, the reproducibility of one dot of the exposure spot is deteriorated in the digital machine, and the image quality is reduced in the digital machine toward higher definition. At present, it is difficult to balance the lifespan.
[0030]
[Problems to be solved by the invention]
An object of the present invention is to provide an electrophotographic photoreceptor having an intermediate layer, a charge generation layer and a charge transport layer on a support in this order, wherein the charge generation layer contains a phthalocyanine pigment as a charge generation substance, An electrophotographic photoreceptor capable of outputting an image free from ghost while maintaining high sensitivity as excellent electrophotographic characteristics even if the electrophotographic photoreceptor has a layer thickness of 9 to 18 μm. An object of the present invention is to provide a process cartridge having a body and an electrophotographic apparatus.
[0031]
Another object of the present invention is to provide an electrophotographic photoreceptor which does not generate white or black streaks due to non-uniform charging, has a long printing life, and can stably output high-quality images. An object of the present invention is to provide a process cartridge having a photoconductor and an electrophotographic apparatus.
[0032]
[Means for Solving the Problems]
The present inventors, as a result of intensive study, using a specific amount of a titanium compound or titanium alkoxide of a specific structure for the intermediate layer, and, by setting the electrostatic capacity of the electrophotographic photoreceptor to a specific numerical range, It has been found that the above problems can be solved.
[0033]
That is, the present invention relates to an electrophotographic photoreceptor having an intermediate layer, a charge generation layer and a charge transport layer on a support in this order, wherein the charge generation layer contains a phthalocyanine pigment as a charge generation substance, In an electrophotographic photosensitive member having a layer thickness of 9 to 18 μm,
A capacitance C per cm ^{2 of the} electrophotographic photosensitive member is 130 pF or more;
The electrophotographic photoreceptor, wherein the intermediate layer is a layer represented by the following (I) or (II).
(I) A layer containing a polyamide resin and a titanium compound having a structure represented by the following formula (1), wherein a value of a ratio (mass ratio) of the polyamide resin to the titanium compound is 1/99 to 45/55. [Outside 4]

[0034]
(In the formula (1), R ¹¹ represents a hydrogen atom or an alkyl group, m is an integer of 1 or more, and when m is 2 or more, R ¹¹ may be the same or different. Represents a monovalent organic group, n is an integer of 1 or more, and when n is 2 or more, L may be the same or different.)
(II) A polyamide resin, a polymer obtained by polymerizing titanium alkoxide and a compound having a structure represented by the following formula (2), and a ratio (mass ratio) of the polyamide resin to the polymer. Layer whose value is 1/99 to 45/55

[0035]
(In the formula (2), R ²¹ and R ²³ each independently represent an alkyl group, a hydroxyl group or an alkoxy group. R ²² represents an alkylene group.)
Further, the present invention is a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0037]
First, the configuration of the electrophotographic photosensitive member used in the present invention will be described.
[0038]
The electrophotographic photoreceptor of the invention has a configuration in which an intermediate layer, a charge generation layer containing a charge generation substance, and a charge transport layer containing a charge transport substance are laminated on a support in this order.
[0039]
The support may be any as long as it has conductivity, such as aluminum or an aluminum alloy, or may have a conductive coating containing a conductive metal oxide and a binder resin thereon. Good.
[0040]
In recent years, printers using laser beams as exposure light have been actively developed, but when the surface of the support is smooth, a phenomenon called laser light interference occurs, and so-called interference fringes appear on the output image. appear. Various techniques have been studied to prevent the interference fringes, but one of the most effective techniques is a method of roughening the surface of the support by honing treatment or the like. Further, the surface area of the support increases due to the surface roughening, sufficient adhesive strength between the support and the intermediate layer can be easily obtained, and good durability can be obtained. The adhesiveness between the support and the intermediate layer can be controlled by changing the amount of the binder resin in the intermediate layer, but the support is preferably roughened to prevent interference fringes, and the surface is roughened. By using the planarized support, it is possible to suppress the occurrence of interference fringes while maintaining image quality without causing white spots or ghosts.
[0041]
Examples of the honing treatment include a dry treatment method and a wet treatment method, and either method may be employed.
[0042]
The wet honing treatment is a method in which a powdered abrasive is suspended in a liquid such as water and sprayed at a high speed on a support surface to roughen the surface.The surface roughness is determined by the spray pressure, speed, and amount of the abrasive. , Type, shape, size, hardness, specific gravity and suspension temperature.
[0043]
The dry honing treatment is a method in which an abrasive is sprayed onto the surface of the support at a high speed with air to roughen the surface, and the surface roughness can be controlled in the same manner as the wet honing treatment.
[0044]
Examples of the abrasive used for the wet or dry honing include particles such as silicon carbide, alumina, iron, and glass beads.
[0045]
In a method in which a conductive film containing a conductive metal oxide and a binder resin is formed on aluminum or an aluminum alloy and used as a support, the conductive film may contain conductive fine particles as a filler. preferable. In this method, by dispersing the conductive fine particles in the conductive film, the laser light is irregularly reflected to prevent interference fringes, and also has an effect of hiding scratches and projections on the support before coating.
[0046]
Examples of the conductive fine particles include titanium oxide, barium sulfate, and the like. If necessary, by providing a conductive coating layer with tin oxide or the like on these fine particles, an appropriate specific resistance as a filler can be obtained. The powder specific resistance of the conductive fine particles is preferably from 0.1 to 1000 Ω · cm, and more preferably from 1 to 1000 Ω · cm.
[0047]
In the present invention, the powder specific resistance was measured using a resistance measuring device Loresta AP (Loresta Ap) manufactured by Mitsubishi Chemical Corporation. The powder to be measured was solidified at a pressure of 500 kg / cm ² and mounted as a coin-shaped sample on the above-mentioned measuring device. The average particle size of the fine particles is preferably from 0.05 to 1.0 μm, and more preferably from 0.07 to 0.7 μm. In the present invention, the average particle size of the fine particles is a value measured by a centrifugal sedimentation method.
[0048]
The content of the filler in the conductive film is preferably from 1.0 to 90% by weight, more preferably from 5.0 to 80% by weight based on the total mass of the conductive film. The conductive film may contain fluorine or antimony as needed.
[0049]
As the binder resin used for the conductive film of the support, phenol resin, polyurethane, polyamide, polyimide, polyamideimide, polyamic acid, polyvinyl acetal, epoxy resin, acrylic resin, melamine resin, polyester and the like are preferable. These resins may be used alone or in combination of two or more. The resin has good adhesiveness to a support, improves dispersibility of the filler, and has good solvent resistance after film formation. Among the above resins, phenol resins, polyurethanes and polyamic acids are particularly preferred.
[0050]
The conductive film can be formed, for example, by dipping or applying a solvent using a Meyer bar or the like. The thickness of the conductive film is preferably from 0.1 to 30 μm, more preferably from 0.5 to 20 μm. Further, the volume resistivity of the conductive film is preferably 10 ¹³ Ω · cm or less, more preferably 10 ¹⁰ to 10 ¹² Ω · cm.
[0051]
In the present invention, the volume resistivity is obtained by applying a conductive film to be measured on an aluminum plate, forming a gold thin film on the coating, and measuring a current value flowing between both electrodes of the aluminum plate and the gold thin film. It was determined by measuring with a pA meter.
[0052]
The conductive film may contain a filler such as zinc oxide or titanium oxide in addition to the conductive fine particles. Further, a leveling agent may be added to enhance surface properties.
[0053]
As described above, the intermediate layer of the electrophotographic photoreceptor of the present invention is a layer represented by the following (I) or (II).
(I) A layer containing a polyamide resin and a titanium compound having a structure represented by the following formula (1), wherein a value of a ratio (mass ratio) of the polyamide resin to the titanium compound is 1/99 to 45/55. [Outside 6]

[0054]
(In the formula (1), R ¹¹ represents a hydrogen atom or an alkyl group, m is an integer of 1 or more, and when m is 2 or more, R ¹¹ may be the same or different. Represents a monovalent organic group, n is an integer of 1 or more, and when n is 2 or more, L may be the same or different.)
Examples of the alkyl group of R ^{11 in} the above formula (1) include a methyl group, an ethyl group, an n-propyl group, and a butyl group.
[0055]
Examples of the monovalent organic group of L in the above formula (1) include β-diketones such as acetylacetone and 2,4-heptanedione, methyl acetoacetate, ethyl acetoacetate, ethyl acetoacetate, propyl acetoacetate and butyl acetoacetate. Such as ketoesters, hydroxycarboxylic acids such as lactic acid, acetic acid, salicylic acid, and malic acid; hydroxycarboxylic acid esters such as methyl lactate, ethyl lactate, ethyl salicylate, and ethyl malate; diethylene glycol, octanediol, and hexanediol. And monovalent groups obtained by removing one hydrogen or hydroxyl group from keto alcohols such as 4-hydroxy-4-methyl-2-pentanone. For example, it is considered that acetic acid having a carboxylic acid group is bonded to titanium by an ester bond, and β-diketone is in a state of a chelate compound by covalent bond and coordinate bond with titanium.
[0056]
Specific examples of the titanium compound having the structure represented by the above formula (1) include titanium-tri-n-butoxide pentanedionate, titanium-di-n-butoxide (bis-2,4-pentanedioate). ), Titanium-triisopropoxide pentanedionate, titanium-diisopropoxide (bis-2,4-pentanedionate), titanium-tri-n-butoxide ethyl acetoacetate, titanium-di-n-butoxide (Bisethylacetoacetate), titanium-tri-n-butoxide methylacetoacetate, titanium-di-n-butoxide (bismethylacetoacetate), titanium-diisopropoxide-bis (2,2,6,6) , -Tetramethyl-3,5, -heptanedionate), Um - bis (triethanolamine) - di -n- butoxide, titanium lactate, methacrylate titanium butoxide, stearyl rate of titanium butoxide, isostearate titanium butoxide and the like.
(II) A polyamide resin, a polymer obtained by polymerizing titanium alkoxide and a compound having a structure represented by the following formula (2), and a ratio (mass ratio) of the polyamide resin to the polymer. Layer whose value is 1/99 to 45/55

[0057]
(In the formula (2), R ²¹ and R ²³ each independently represent an alkyl group, a hydroxyl group or an alkoxy group. R ²² represents an alkylene group.)
Examples of the titanium alkoxide include titanium butoxide, titanium propoxide, and titanium ethoxide.
[0058]
In the formula (2), examples of the alkyl group of R ²¹ and R ²³ include a methyl group, an ethyl group, an n-propyl group, and a butyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. And butoxy groups. The alkylene group of R ^22, methine group, ethyne group, propyne group, including butyne group.
[0059]
And, a titanium compound having a structure represented by the above formula (1) or a polyamide resin used in combination with a polymer obtained by polymerizing titanium alkoxide and a compound having a structure represented by the above formula (2) Any one may be used, but quaternary nylon copolymer of Nylon 6-66-610-12 and N-methoxymethylated nylon are preferred from the viewpoints of solubility and environmental fluctuation of volume resistivity. The polyamide resin may be used alone or in combination of two or more.
[0060]
The value of the ratio (mass ratio) of the polyamide resin to the titanium compound or the polymer must be from 1/99 to 45/55, preferably from 2/98 to 30/70. If the proportion of the polyamide resin is too large, the influence of the hygroscopicity of the polyamide resin becomes large, and the electrophotographic characteristics greatly depend on environmental changes, and a positive ghost occurs. If it is too large, unevenness is likely to occur at the time of coating, and the adhesion between the support and the intermediate layer will be reduced.
[0061]
By adopting such an intermediate layer, an electrophotographic photoreceptor which has good image characteristics such as fog and black spots, good adhesion, and does not generate ghost even when phthalocyanine having high sensitivity and a large amount of charge generation is used. Can be provided.
[0062]
A charge generation layer is formed on the intermediate layer.
[0063]
The charge generating substance used in the electrophotographic photoreceptor of the present invention is a phthalocyanine pigment, and specifically, a phthalocyanine having a metal-free phthalocyanine or a central metal such as indium chloride, gallium chloride, oxytitanium, zinc, and vanadium. Pigments. Among these, electrophotographic properties, in terms of image quality, metal-free phthalocyanine, oxytitanium phthalocyanine, hydroxygallium phthalocyanine, and halogenated gallium phthalocyanine such as chlorogallium phthalocyanine are preferable, and oxytitanium phthalocyanine and hydroxygallium phthalocyanine are particularly preferable. .
[0064]
The charge generation layer may contain a charge generation substance other than the phthalocyanine pigment. Examples include selenium-tellurium, pyrylium, thiapyrylium dyes, anthantrone, dibenzopyrenequinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments.
[0065]
The charge generation layer is formed by mixing the above charge generation substance with a binder resin and a solvent in an amount of 0.3 to 4 times (mass ratio), a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an attritor, a roll mill, or a liquid collision type high speed. It is formed by sufficiently dispersing using a disperser or the like, applying a dispersion, and drying.
[0066]
The thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.1 to 2 μm.
[0067]
A charge transport layer is formed on the charge generation layer.
[0068]
The charge transport layer is formed by applying and drying a coating material in which a charge transport material and a binder resin are dissolved in a solvent. Examples of the charge transport material used include a triarylamine compound, a hydrazone compound, a stilbene compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound.
[0069]
The charge transport layer is formed by applying and drying a coating solution in which the above-described charge transport material and a binder resin in an amount of 0.5 to 2 times (mass ratio) thereof are dissolved.
[0070]
As the binder resin of the charge transport layer, a polyarylate resin having a repeating structural unit represented by the following formula (3) alone is used.
[Outside 8]

[0071]
(In the formula (3), X ³¹ represents a carbon atom or a single bond (in the case of a single bond, R ³⁵ and R ³⁶ are not present.) R ^{31 to} R ³⁴ each independently represent a hydrogen atom, a halogen atom, R ³⁵ and R ³⁶ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkyl group; An aryl group or an alkylidene group formed by bonding R ³⁵ and R ^36. R ^{37 to} R ⁴⁰ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or Represents a substituted or unsubstituted aryl group.)
Alternatively, resins of other structures such as polyarylate resin, polycarbonate resin, polyester resin, polymethacrylic acid ester, polystyrene resin, acrylic resin, and polyamide resin, and organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene. May be used as a mixture.
[0072]
Specific examples of the repeating structural unit represented by the above formula (3) are shown below, but the present invention is not limited thereto.
[0073]
[Outside 9]

[0074]
[Outside 10]

[0075]
[Outside 11]

[0076]
[Outside 12]

[0077]
[Outside 13]

[0078]
In the electrophotographic photoreceptor of the present invention, either a homopolymer composed of a single repeating structural unit represented by the above formula (3) or a copolymer composed of two or more types of repeating structural units Good.
[0079]
In the present invention, the viscosity average molecular weight of the polyarylate having a repeating structural unit represented by the above formula (3) is preferably from 10,000 to 200,000, and more preferably from 15,000 to 100,000. More preferably, there is.
[0080]
The thickness of the charge transport layer of the electrophotographic photoreceptor of the present invention is 9 to 18 μm. When the thickness of the charge transport layer is less than 9 μm, the charging ability of the electrophotographic photoreceptor is not sufficient. When the thickness is more than 18 μm, the charge stability is reduced and uneven charging occurs.
[0081]
In order to further suppress the occurrence of the ghost phenomenon, the electric field intensity applied to the electrophotographic photosensitive member is preferably set to 3.3 × 10 ^{5 to} 8.1 × 10 ⁵ V / cm.
[0082]
The contact charging method in which the electrophotographic photosensitive member is charged by the contact charging member arranged in contact with the electrophotographic photosensitive member is based on Paschen's law in the space-breaking discharge in a minute space near the contact portion between the electrophotographic photosensitive member and the contact charging member. Done by
[0083]
In a general electrophotographic apparatus, a drum-shaped or belt-shaped electrophotographic photoreceptor is used, and either type is charged while rotating or moving with respect to a contact charging member. That is, the electrophotographic photosensitive member is divided into an upstream side and a downstream side with a contact portion between the electrophotographic photosensitive member and the contact charging member as a boundary, and charging is performed in each of the upstream and downstream minute spaces. At this time, a gap breaking discharge is performed according to the Paschen's rule. Due to the nature of such a charging mechanism, the relative permittivity, film thickness (capacitance) of the electrophotographic photoreceptor, the resistance value of the charging member, the applied voltage, etc. It is not easy to uniformly charge due to the many factors described above. As one of the countermeasures, as described above, a method of applying an AC voltage by a pulsating voltage superimposed thereon has been proposed.
[0084]
The electrophotographic photoreceptor of the present invention has a capacitance C per cm ^{2 of the} electrophotographic photoreceptor of 130 pF or more even if a method of applying only a DC voltage (DC charging method) is used for charging. As a result, uniform charging can be achieved in the same manner as when the voltage is applied by the pulsating voltage.
[0085]
That is, by setting the capacitance C per cm ^{2 of the} electrophotographic photosensitive member to 130 pF or more, generation of an electric field in the opposite direction, which is considered to be a cause of a streak image, can be suppressed stably, and the overall charging characteristics It is considered that uniform charging without a streak image or the like could be performed as in the case of applying the pulsating voltage. If the AC voltage is not superimposed, there is no technical problem when the AC voltage is superimposed.
[0086]
In the present invention, from the viewpoint of the charging ability of the charging means, the electrostatic capacity C per 1 cm ^{2 of the} electrophotographic photosensitive member is preferably 500 pF or less, and more preferably 350 pF or less.
[0087]
Furthermore, in the present invention, when the charge transport layer is a surface layer of the electrophotographic photosensitive member, by using a polyarylate resin as a binder resin of the charge transport layer, the mechanical strength of the electrophotographic photosensitive member is improved, If the charging method is a DC charging method, damage to the electrophotographic photosensitive member due to charging is also reduced, so that mechanical wear of the electrophotographic photosensitive member is extremely reduced, and even if the thickness of the charge transport layer is 9 to 18 μm. In addition, the charging uniformity of DC charging can be significantly improved without sacrificing the life of the electrophotographic photosensitive member.
[0088]
Next, a schematic configuration of the electrophotographic apparatus of the present invention will be described with reference to FIG. However, the schematic configuration of the electrophotographic apparatus shown in FIG. 1 is an example, and the present invention is not limited to this.
[0089]
The apparatus shown in FIG. 1 uniformly charges the electrophotographic photosensitive member only with a DC voltage by a charging roller serving as a charging means 21 which is arranged in contact with a drum-shaped electrophotographic photosensitive member 26 (for example, a photosensitive drum having a diameter of 30 mm). I do.
[0090]
After charging, an image portion is exposed by a laser beam from an exposure unit (not shown) to form an electrostatic latent image. The developing unit 22 converts the image into a visible image (toner image). The transfer roller 27 transfers the toner image to a transfer material 28. 23 is a regulating blade, 24 is a developing roller, and 25 is a supply roller.
[0091]
The surface of the electrophotographic photoreceptor 26 after the image transfer is cleaned by a cleaning unit 30 having a cleaning blade 29 to remove the untransferred toner, and is used repeatedly for image formation.
[0092]
In the electrophotographic apparatus of the present invention, it is not always necessary to perform a charge elimination process on the surface of the electrophotographic photosensitive member by pre-exposure light from the pre-exposure unit.
[0093]
Further, the electrophotographic photosensitive member 26 and at least one of the charging unit 21, the developing unit 22, the transfer unit 27 and the cleaning unit 30 are integrally supported, and a process cartridge detachable from the main body of the electrophotographic apparatus may be used. Can be done
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and the like.
[0095]
In the examples, “parts” means “parts by mass”.
[0096]
<Electrophotographic photoreceptor production example 1>
An aluminum base tube (ED tube) having an outer diameter of 30.5 mm, an inner diameter of 28.5 mm, and a length of 260.5 mm of A3003 obtained by hot extrusion was prepared as a support.
[0097]
Next, using a liquid (wet) honing apparatus (manufactured by Fuji Seiki Seisakusho), a liquid honing treatment was performed under the following conditions.
Liquid honing conditions Abrasive abrasive grains: spherical alumina beads having an average particle diameter of 30 μm (trade name: CB-A30S, manufactured by Showa Denko KK)
Suspension medium: water,
Abrasive / suspension medium: 1/9 (volume ratio)
Rotation speed of aluminum cutting tube: 1.67 s ^-1
Air blowing pressure: 0.165MPa
Gun moving speed: 13.3 mm / s
Distance between gun nozzle and aluminum tube: 180mm
Honing abrasive discharge angle: 45 °
Number of times of polishing liquid projection: 1 time Measurement of surface roughness was performed according to JISB0601, using a surface roughness meter surf coder SE3500 manufactured by Kosaka Laboratory Co., Ltd., with a cutoff of 0.8 mm and a measurement length of 8 mm. Was. The surface roughness of the support after honing was Rmax = 3.0 μm, Rz = 1.55 μm, Ra = 0.24 μm, and Sm = 34 μm.
[0098]
Next, 90 parts of an 85% butanol solution of titanium-tetra-n-butoxide (manufactured by Kanto Chemical Co., Ltd.) was dropped into 160 parts of methoxyethanol, and a mixed solution of 160 parts of methoxyethanol / 11 parts of water was further added.
[0099]
A solution obtained by adding 20 parts of acetylacetone as a compound having the structure represented by the above formula (2) to 200 parts of methanol was dropped into the mixed solution of titanium-tetra-n-butoxide and water, and then nylon 6 was used as a polyamide resin. An intermediate layer coating solution obtained by mixing 85 parts of a 10% by mass methanol solution of -66-610-12 quaternary nylon copolymer (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) was coated on the support. The resultant was heated at 150 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.3 μm.
[0100]
Next, 4 parts of oxytitanium phthalocyanine having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° in Bragg angles (2θ ± 0.2 °) in characteristic X-ray diffraction of CuKα. , 2 parts of polyvinyl butyral (trade name: Eslek BM2 manufactured by Sekisui Chemical) and 60 parts of cyclohexanone were dispersed for 4 hours by a sand mill using glass beads having a diameter of 1 mm, and 100 parts of ethyl acetate was added thereto to disperse the charge generation layer. A liquid was prepared. This was applied on the above-mentioned intermediate layer by a dip coating method, and dried to form a charge generation layer having a thickness of 0.3 μm.
[0101]
Next, in order to form a charge transport layer, a paint for the charge transport layer was prepared.
[0102]
10 parts of a polyarylate resin having a repeating structural unit represented by the above formula (3-2) as a binder resin, 9 parts of an amine compound having a structure represented by the following formula (A),
[Outside 14]

[0103]
1 part of an amine compound having a structure represented by the following formula (B):
[Outside 15]

[0104]
It was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 50 parts of dichloromethane. This paint was applied on the charge generation layer by a dip coating method and dried at 120 ° C. for 2 hours to form a charge transport layer having a thickness of 9 μm.
[0105]
Thus, an electrophotographic photosensitive member 1 was produced.
[0106]
<Electrophotographic photoreceptor production example 2>
An electrophotographic photoreceptor 2 was produced in the same manner as in the electrophotographic photoreceptor production example 1, except that the thickness of the charge transport layer was changed to 14 μm.
[0107]
<Electrophotographic photoreceptor production example 3>
An electrophotographic photosensitive member 3 was manufactured in the same manner as in the electrophotographic photosensitive member manufacturing example 1, except that the thickness of the charge transport layer was changed to 18 μm.
[0108]
<Electrophotographic photoreceptor production example 4>
An electrophotographic photoreceptor 4 was produced in the same manner as in the electrophotographic photoreceptor production example 1, except that the thickness of the charge transport layer was changed to 20 μm.
[0109]
<Electrophotographic photoreceptor manufacturing example 5>
An electrophotographic photosensitive member 5 was manufactured in the same manner as in the electrophotographic photosensitive member manufacturing example 1, except that the thickness of the charge transport layer was changed to 25 μm.
[0110]
(Examples 1 to 3 and Comparative Examples 1 and 2)
Using the electrophotographic photoreceptors 1 to 5 as shown in Table 1, the Hewlett-Packard LBP “Laser Jet 4000” (process speed 94.2 mm / s) having the configuration shown in FIG. The evaluation was performed by setting the process conditions.
[0111]
Electrophotographic photosensitive member dark area potential: -600V
Electrophotographic photosensitive member light portion potential: -150V
Development bias: -350V (DC voltage only)
Initial image evaluation was performed in an environment of 15 ° C./10% RH. The evaluation of the image was performed as follows.
[0112]
A ghost was evaluated using a halftone test chart in which a 25 mm square solid black portion was arranged at the portion of one rotation of the electrophotographic photosensitive member from the start of printing the printed image, and one dot was printed in a Keima pattern after the second rotation of the electrophotographic photosensitive member. .
[0113]
Further, a streak image due to charging unevenness was evaluated using a halftone test chart in which one dot was printed in a Keima pattern over the entire print surface and a solid black image.
[0114]
Table 1 shows the evaluation results.
[0115]
The capacitance C in the present invention was determined by the following procedure using the capacitance measuring device shown in FIG.
[0116]
1. A sample (electrophotographic photosensitive member) whose capacitance (C _X ) is to be measured and a capacitor 46 having a known capacitance (C ₀ ) are connected as shown in FIG. 2 and corona charging to which a predetermined DC voltage is applied The sample (electrophotographic photosensitive member) 44 was charged by the container 41.
[0117]
2. With the switch SW turned off, the surface potential of the sample (electrophotographic photosensitive member) 44 was measured by the surface potentiometer 42. The measurement value at this time was set to V _1.
[0118]
3. Next, the switch SW was turned on, and the surface potential of the sample (electrophotographic photosensitive member) 44 was measured again by the surface electrometer 42. The measurement value at this time was set to V _2.
[0119]
4. The calculation method of the capacitance C _X is as follows.
[0120]
V ₁ = V ₀ + V _X = q / C ₀ + q / C _X (1)
V ₂ = V _X = q / C _X (2)
When q is eliminated from the above equations (1) and (2), C _X = [(V ₁ −V ₂ ) / V ₂ ] · C ₀
It becomes. Then, the capacitance per unit area is determined by dividing the measured capacitance C _X by the surface area of the sample (electrophotographic photoreceptor).
[0121]
In FIG. 2, 43 is an electric charge, and 45 is an electrode.
[0122]
[Table 1]

[0123]
<Electrophotographic photoreceptor manufacturing example 6>
An aluminum base tube (ED tube) of A3003 obtained by hot extrusion having an outer diameter of 30.5 mm, an inner diameter of 28.5 mm, and a length of 260.5 mm was prepared.
[0124]
120 parts of barium sulfate fine particles (coating ratio: 50% by weight, powder specific resistance: 700 Ω · cm) having a coating layer formed of tin oxide, and a resol-type phenol resin (trade name: Plyofen J-325, Dainippon Ink and Chemicals, Inc.) A solution consisting of 70 parts of Industrial Co., Ltd., solid content 70%) and 100 parts of 2-methoxy-1-propanol was dispersed in a ball mill for 20 hours to prepare a coating liquid for a conductive film. The average particle size of the filler contained in the coating solution was 0.22 μm). This coating solution was applied on the above-mentioned aluminum tube by a dip coating method, and was heated and cured at 140 ° C. for 30 minutes to form a 15 μm-thick conductive film, which was used as a support.
[0125]
Next, 90 parts of an 85% butanol solution of titanium-tetra-n-butoxide (manufactured by Kanto Chemical Co., Ltd.) was dropped into 160 parts of methoxyethanol, and a mixed solution of 160 parts of methoxyethanol / 11 parts of water was further added.
[0126]
A solution obtained by adding 20 parts of acetylacetone as a compound having the structure represented by the above formula (2) to 200 parts of methanol was dropped into the mixed solution of titanium-tetra-n-butoxide and water, and then nylon 6 was used as a polyamide resin. The intermediate layer coating solution obtained by mixing 7.7 parts of a 10% by mass methanol solution of quaternary nylon copolymer (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) of -66-610-12 was supported above. Dip coating was performed on the body and heated at 150 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.3 μm.
[0127]
Next, 2 parts of hydroxygallium phthalocyanine crystal having strong peaks at 7.4 ° and 28.2 ° of Bragg angles (2θ ± 0.2 °) in characteristic X-ray diffraction of CuKα, polyvinyl butyral (trade name: Eslec BM2) 1 part and 60 parts of cyclohexanone were dispersed in a sand mill using glass beads having a diameter of 1 mm for 3 hours, and then diluted with 50 parts of cyclohexanone and 130 parts of ethyl acetate. Paint was prepared. This was applied onto the above-mentioned intermediate layer by a dip coating method, and dried at 100 ° C. for 10 minutes to form a 0.2 μm-thick charge generation layer.
[0128]
The charge transport layer was formed in the same manner as in Production Example 2 of the electrophotographic photoreceptor.
[0129]
Thus, an electrophotographic photosensitive member 6 was produced.
[0130]
<Electrophotographic photoreceptor production example 7>
An electrophotographic photosensitive member 7 was produced in the same manner as in the electrophotographic photosensitive member manufacturing example 6, except that the polyamide resin solution of the coating solution for the intermediate layer was changed to 85 parts.
[0131]
<Electrophotographic photoreceptor production example 8>
An electrophotographic photoreceptor 8 was produced in the same manner as in the electrophotographic photoreceptor production example 6, except that the intermediate layer was formed as described below.
[0132]
128 parts of a 60% butanol solution of titanium-di-n-butoxide (bis-2,4-pentanedionate) and 150 parts of methoxypropanol were mixed, and a mixed solution of 150 parts of methoxypropanol / 11 parts of water was further added. An intermediate layer coating solution obtained by further mixing 325 parts of a 10% by mass methanol solution of N-methoxymethylated nylon (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Industry Co., Ltd.) is dip-coated on the support. And heated at 150 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.3 μm.
[0133]
<Electrophotographic photoreceptor production example 9>
An electrophotographic photosensitive member 9 was produced in the same manner as in the electrophotographic photosensitive member manufacturing example 8 except that the polyamide resin solution of the coating solution for the intermediate layer was changed to 625 parts.
[0134]
<Electrophotographic photoreceptor production example 10>
An electrophotographic photoreceptor 10 was prepared in the same manner as in the electrophotographic photoreceptor manufacture example 6, except that the polyamide resin was not used for the intermediate layer.
[0135]
<Electrophotographic photoreceptor production example 11>
In electrophotographic photoreceptor production example 7, in the same manner as in electrophotographic photoreceptor production example 7, except that titanium acetylacetonate was added instead of titanium-tetra-n-butoxide of the intermediate layer coating solution and acetylacetone was not used. However, the electrophotographic photosensitive member could not be produced because fine cracks occurred in the film of the intermediate layer.
[0136]
<Example 12 of manufacturing electrophotographic photosensitive member>
An electrophotographic photosensitive member 12 was produced in the same manner as in the electrophotographic photosensitive member manufacturing example 6, except that the polyamide resin of the intermediate layer coating liquid was changed to 1150 parts.
[0137]
<Example 13 of manufacturing electrophotographic photosensitive member>
In the electrophotographic photoreceptor production example 7, except that a butyral resin (Eslex BM-S, manufactured by Sekisui Chemical Co., Ltd.) was used instead of the polyamide resin as the binder resin for the coating liquid for the intermediate layer, An electrophotographic photosensitive member 13 was produced in the same manner as in Example 7.
[0138]
(Examples 4 to 7 and Comparative Examples 3 to 6)
Using the electrophotographic photoreceptors 6 to 13 as shown in Table 2, the Hewlett-Packard LBP “Laser Jet 4000” (process speed 94.2 mm / s) having the configuration shown in FIG. The evaluation was performed by setting the process conditions.
[0139]
Electrophotographic photosensitive member dark area potential: -600V
Electrophotographic photosensitive member light portion potential: -150V
Development bias: -350V (DC voltage only)
Electrostatic capacity of photoreceptor: 185 pF
Electric field strength 4.29 × 10 ⁵
Initial image evaluation was performed in an environment of 15 ° C./10% RH. The evaluation of the image was performed as follows.
[0140]
A ghost was evaluated using a halftone test chart in which a 25 mm square solid black portion was arranged at the portion of one rotation of the electrophotographic photosensitive member from the start of printing the printed image, and one dot was printed in a Keima pattern after the second rotation of the electrophotographic photosensitive member. .
[0141]
Also, a streak image due to charging unevenness was evaluated using a halftone test chart in which one dot was printed in a Keima pattern on the entire print surface and a solid black image, and black spots and fog were evaluated using a solid white image.
[0142]
Next, a continuous image output test was performed on 15,000 sheets of A4 size paper in a character pattern printed at an area ratio of 4%, and image evaluation was performed.
[0143]
Table 2 shows the evaluation results.
[0144]
[Table 2]

[0145]
<Electrophotographic photoreceptor production example 14>
An electrophotographic photoreceptor 14 was produced in the same manner as in the electrophotographic photoreceptor production example 2, except that the charge generation layer was formed as described below.
[0146]
2.5 parts of hydroxygallium phthalocyanine crystal having strong peaks at 7.4 ° and 28.2 ° in Bragg angles (2θ ± 0.2 °) in characteristic X-ray diffraction of CuKα, polyvinyl butyral (trade name: Eslek BM2, 1 part of Sekisui Chemical Co., Ltd.) and 60 parts of cyclohexanone were dispersed in a sand mill using glass beads having a diameter of 1 mm for 3 hours, and then diluted by adding 50 parts of cyclohexanone and 130 parts of ethyl acetate to form a charge generation layer. A paint was prepared. The coating material for a charge generation layer was applied onto the intermediate layer by dip coating and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.
[0147]
<Electrophotographic photoreceptor production example 15>
In electrophotographic photoreceptor production example 14, in the binder resin of the charge transport layer, a copolymer having a repeating structural unit represented by the above formula (3-2) and a repeating structural unit represented by the above formula (3-24) ( An electrophotographic photoreceptor 15 was prepared in the same manner as in the electrophotographic photoreceptor production example 14 except that a polyarylate resin (weight average molecular weight: 95,000) having a copolymerization ratio of 50:50 (molar ratio) was used.
[0148]
<Electrophotographic photoreceptor production example 16>
Electrophotographic photoreceptor production example except that the binder resin of the charge transport layer was changed to bisphenol Z type polycarbonate (trade name: Iupilon Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) in Production Example 14 of the electrophotographic photoreceptor. An electrophotographic photoreceptor 16 was produced in the same manner as in No. 14.
[0149]
(Examples 8 to 11 and Comparative Examples 7 to 9)
The electrophotographic photosensitive members 14 to 16 were evaluated in the same manner as in Example 1. However, the electric field intensity applied to the electrophotographic photosensitive member was changed by changing the dark portion potential of the electrophotographic photosensitive member as shown in Table 3.
[0150]
Next, a continuous image output test was performed on 15,000 sheets of A4 size paper in a character pattern printed at an area ratio of 4%, and image evaluation was performed.
[0151]
Table 3 shows the evaluation results.
[0152]
[Table 3]

[0153]
【The invention's effect】
According to the present invention, there is provided an electrophotographic photoreceptor having an intermediate layer, a charge generation layer and a charge transport layer on a support in this order, wherein the charge generation layer contains a phthalocyanine pigment as a charge generation substance, An electrophotographic photoreceptor capable of outputting an image free from ghost while maintaining high sensitivity as an excellent electrophotographic characteristic even if the electrophotographic photoreceptor has a layer thickness of 9 to 18 μm. A process cartridge and an electrophotographic apparatus having a body can be provided.
[0154]
Further, an electrophotographic photosensitive member capable of stably outputting a high-quality image having a long print life without generating white stripes and black stripes due to uneven charging, a process cartridge having the electrophotographic photosensitive member, and an electronic device. A photographic device can be provided.
[Brief description of the drawings]
FIG. 1 is a view showing a schematic configuration of an electrophotographic apparatus having an electrophotographic photosensitive member of the present invention.
FIG. 2 is a diagram showing a schematic configuration of a capacitance measuring device.
[Explanation of symbols]
Reference Signs List 21 charging means 22 developing means 23 regulating blade 24 developing roller 25 supply roller 26 electrophotographic photoreceptor 27 transfer means 28 transfer material 29 cleaning blade 30 cleaning means 41 corona charger 42 surface voltmeter 43 charge 44 sample (capacitance unknown C _X )
45 Electrode 46 Condenser (Capacitance known C ₀ )
SW switch

Claims (15)

An electrophotographic photoreceptor having an intermediate layer, a charge generation layer and a charge transport layer on a support in this order, wherein the charge generation layer contains a phthalocyanine pigment as a charge generation substance, and the charge transport layer has a thickness of 9 １８18 μm in the electrophotographic photosensitive member,
A capacitance C per cm ^{2 of the} electrophotographic photosensitive member is 130 pF or more;
The electrophotographic photosensitive member, wherein the intermediate layer is a layer represented by the following (I) or (II).
(I) A layer containing a polyamide resin and a titanium compound having a structure represented by the following formula (1), wherein a ratio (mass ratio) of the polyamide resin to the titanium compound is 1/99 to 45/55. [Outside 1]

(In the formula (1), R ¹¹ represents a hydrogen atom or an alkyl group, m is an integer of 1 or more, and when m is 2 or more, R ¹¹ may be the same or different. Represents a monovalent organic group, n is an integer of 1 or more, and when n is 2 or more, L may be the same or different.)
(II) A polyamide resin and a polymer obtained by polymerizing titanium alkoxide and a compound having a structure represented by the following formula (2), and a ratio (mass ratio) of the polyamide resin to the polymer. Layer whose value is 1/99 to 45/55

(In the formula (2), R ²¹ and R ²³ each independently represent an alkyl group, a hydroxyl group or an alkoxy group. R ²² represents an alkylene group.) The electrophotographic photosensitive member according to claim 1, wherein the phthalocyanine pigment is oxytitanium phthalocyanine or hydroxygallium phthalocyanine. The electrophotographic photoreceptor according to claim 1 or 2, wherein the charge transport layer contains a polyarylate resin having a repeating structural unit represented by the following formula (3).
[Outside 3]

(In the formula (3), X ³¹ represents a carbon atom or a single bond (in the case of a single bond, R ³⁵ and R ³⁶ are not present.) R ^{31 to} R ³⁴ each independently represent a hydrogen atom, a halogen atom, R ³⁵ and R ³⁶ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkyl group; An aryl group or an alkylidene group formed by bonding R ³⁵ and R ^36. R ^{37 to} R ⁴⁰ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or Represents a substituted or unsubstituted aryl group.) The electrophotographic photosensitive member according to claim 1, wherein the charge transport layer is a surface layer of the electrophotographic photosensitive member. An electrophotographic apparatus main body that integrally supports the electrophotographic photosensitive member according to claim 1 and at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit, and a cleaning unit. A process cartridge, which is detachable from the process cartridge. The electric field strength applied to the electrophotographic photoconductor when the electrophotographic photoconductor is charged by the charging unit, the electrophotographic photoconductor and the charging unit being integrally supported and detachable from the main body of the electrophotographic apparatus. The process cartridge according to claim ^{5, wherein the} value is 3.3 × 10 ^{5 to} 8.1 × 10 ⁵ [V / cm]. 6. The electrophotographic photoreceptor and the charging means are integrally supported, and are detachable from an electrophotographic apparatus main body, wherein the charging means has a contact charging member arranged in contact with the electrophotographic photoreceptor. 7. The process cartridge according to 6. The process cartridge according to claim 7, wherein the contact charging member is a charging roller. The electrophotographic photoreceptor and the charging unit are integrally supported, and are detachably attached to an electrophotographic apparatus main body, wherein the charging unit is a unit for charging the electrophotographic photoreceptor only with a DC voltage. 9. The process cartridge according to any one of items 8. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposing unit, a developing unit, and a transferring unit. The electric field intensity applied to the electrophotographic photoconductor when the electrophotographic photoconductor is charged by the charging unit is 3.3 × 10 ^{5 to} 8.1 × 10 ⁵ [V / cm]. Electrophotographic equipment. The electrophotographic apparatus according to claim 10, wherein the charging unit includes a contact charging member disposed in contact with the electrophotographic photosensitive member. The electrophotographic apparatus according to claim 12, wherein the contact charging member is a charging roller. 14. The electrophotographic apparatus according to claim 10, wherein said charging means is means for charging said electrophotographic photosensitive member only with a DC voltage. The electrophotographic apparatus according to any one of claims 10 to 14, wherein the charging unit does not include a pre-exposure unit that performs a charge removal process on the electrophotographic photosensitive member before charging the electrophotographic photosensitive member.

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