JP2004258346A - Organic photoreceptor, method for manufacturing organic photoreceptor, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor which improves wear resistance by increasing film strength, and is capable of forming an electrophotographic image protected from image blur, etc., and having good sharpness. <P>SOLUTION: In the organic photoreceptor including a photosensitive layer on a conductive support, the photosensitive layer has a hardened film formed from a hardenable composition containing a charge transport compound having a polymerizable group and silica having a polymerizable group. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３３】
【化２】

【００３４】
【化３】

【００３５】
【化４】

【００３６】
【化５】

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【化６】

【００３８】
【化７】

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【化８】

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【化９】

【００４１】
本発明の重合性基を有するシリカとはシリカ粒子およびそれと化学的に結合している有機化合物とからなり、該有機化合物は、重合性不飽和基又は開環重合性基、下記式（１）で表される基および下記式（２）
【００４２】
【化１０】

【００４３】
（式中、Ｘは−ＮＨ−、−Ｏ−および−Ｓ−から選ばれ、Ｙは酸素原子およびイオウ原子から選ばれる、但しＸが−Ｏ−のときＹはイオウ原子である）で表される基を有しており、そしてシリカ粒子と有機化合物とはシリルオキシ基を介して結合している反応性シリカ粒子（重合性基を有するシリカ）で提供される。
【００４４】
さらに、本発明によれば、本発明の重合性基を有するシリカは、（ａ）分子中に加水分解性シリル基、重合性基（重合性不飽和基又は開環重合性基）、上記式（１）で表される基および上記式（２）で表される基を含有する化合物（以下「重合性基を有する加水分解性シラン」という）と（ｂ）粉体状シリカおよびコロイダルシリカから選ばれるシリカ粒子と混合し、加水分解反応させ、重合性不飽和基（又は開環重合性基）を有する加水分解性シランと前基（ｂ）に示すシリカ粒子を化学的に結合させる方法によって製造される。
【００４５】
前記シリカ粒子の平均粒径は、数平均一次粒径において１０ｎｍ以上５００ｎｍ以下の範囲のものが好ましく、より好ましくは１０ｎｍ〜２００ｎｍ、特に好ましくは、１５ｎｍ〜１００ｎｍである。
【００４６】
前記シリカ粒子の数平均一次粒径は、例えば、透過型電子顕微鏡観察によって１００００倍に拡大し、ランダムに１００個の粒子を一次粒子として観察し、画像解析によりフェレ径の数平均径として測定される。
【００４７】
本発明方法に用いられる重合性基を有する加水分解性シラン（ａ）は分子中に加水分解性シリル基、上記式（１）で表される基および（２）で表される基および重合性基（重合性不飽和基又は開環重合性基）を構成成分として少なくともそれぞれ１個含むことを特徴とする。加水分解性シリル基は、加水分解および縮合反応によりシリカ粒子の表面に存在するシラノール基と結合する成分であり、また、重合性基とは、活性ラジカル種により付加重合を経て分子間で化学架橋する成分である。また、上記式（１）で表される基および（２）で表される基は、これら加水分解性シリル基を有する分子片と重合性基を有する分子片とを直接もしくは他の分子片を介して結合する構成単位であると同時に分子間において水素結合による適度の凝集力を発生させ、硬化組織物に優れた力学的強度、基材との密着性、耐熱性等の性能を発生せしめる役割を果たすと推定される。
【００４８】
上記加水分解性シリル基としては、例えばアルコキシシリル基等のカルボキシレートシリル基、アセトキシシリル基等のカルボキシレートシリル基；クロロシリル基等のハロゲン化シリル基；アミノシリル基、オキシムシリル基、ヒドリドキシ基等を挙げることができる。加水分解性シリル基の定義としては、水との反応において酸、塩基もしくはそれ以外の触媒を併用した条件でシラノール基を形成する化合物を含む。これらの中で好ましいのはアルコキシシリル基である。
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また、上記式（１）で表される基には、下記式で表される基が包含される。
【００５０】
【化１１】

【００５１】
さらに、重合性基としては、例えばアクリロキシ基、メタクリロキシ基、ビニル基、プロぺニル基、ブタジエニル基、スチリル基、ニチニイル基、シンナモイル基、マレエート基、アクリルアミド基、カプロラクタン基等を例示することができる。これらの中で、アクリロキシ基を好ましいものとして挙げることができる。
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前記重合性基を有する加水分解性シランの化合物例を下記に示す。
【００５３】
【化１２】

【００５４】
ＪＳ−１の合成例
乾燥空気中、メルカプトプロピルトリメトキシシラン２２１部、ジブチル錫ジラウレート１部からなる溶液に、１，３−ビス（イソシアネートメチル）シクロヘキサン２２３部を撹拌しながら５０℃で、１時間かけて滴下後、７０℃３時間撹拌した。これにペンタエリスリトールトリアクリレート５５５部を３０℃で、１時間かけて滴下後、６０℃で、１０時間撹拌し、上記ＪＳ−１の化合物を得た。
【００５５】
又、別のタイプの重合性基を有する加水分解性シランとしては、特開平９−３１９１３０号公報に記されたようなシリルアクリレート化合物が挙げられる。即ち、下記のような重合性基を有する加水分解性シランが挙げられる。
【００５６】
【化１３】

【００５７】
本発明の重合性基を有する電荷輸送性化合物及び重合性基を有するシリカを含有する硬化性組成物から形成された硬化膜（乾燥し、固形化した膜のこと：以後、本発明の硬化膜とも云う）は、電荷輸送能を有するので電荷輸送層としても用いることができるが、電荷輸送層とは別の表面保護層として用いることがより好ましい。この場合、表面保護層は電荷輸送能を有するので、感光層の定義の範囲内に含める。
【００５８】
又、本発明の硬化性組成物中には、重合性基を有する電荷輸送性化合物及び重合性基を有するシリカ以外に、重合性単量体を含有させてもよい。該重合性単量体とは、上記不飽和重合、開環重合等で連鎖重合反応が進行する不飽和重合性基、開環重合性基そして異性化重合性基を有する連鎖重合性単量体をいう。
【００５９】
以下に本発明で好ましく用いられる重合性単量体の具体例を一般式も含めて下記に示す。
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【化１４】

【００６１】
【化１５】

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【化１６】

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【化１７】

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尚、これらの化合物は特開平７−９７４１５号公報等に記載されている。
又、重合性単量体としては、次のような化合物も挙げられる。
【００６５】
ジエチレングリコールジアクリレート、トリエチレングリコールジアクリレート、ジエチレングリコールジアクリレート、ポリエチレングリコールジアクリレート、ポリエチレングリコールジメタクリレート、ポリプロピレングリコールジメタクリレート、ブチレングリコールジアクリレート、ブチレングリコールジメタクリレート、ネオペンチルグリコールジアクリレート、ネオペンチルグリコールジメタクリレート、１，４−ブタンジオールジアクリレート、１，６−ヘキサンジオールジアクリレート、１，６−ヘキサンジオールジメタクリレート、ペンタエリトリトールジアクリレート、ペンタエリトリトールトリアクリレート、トリメチロールプロパントリアクリレート、トリメチロールプロパントリメタアクリレート、テトラメチロールメタンテトラアクリレート、２，２，５，５−テトラヒドロキシメチルシクロペンタノンテトラアクリレートなどのアクリルエステル、あるいは多価カルボン酸のアリルエステルとしてジアリルフタレート、ジアリルイソフタレート、ジアリルマレート、ジアリルアジペート、ジアリルジグリコラート、ジエチレングリコールビスアリルカルボネート、トリメリット酸トリアリルエステルなどのビニル基を持つ多官能モノマー、又はビスフェノールＡなどの多価フェノール化合物とグリシジルアクリレート等が挙げられる。
【００６６】
上記重合性単量体の中でも、重合性基が５以上、好ましくは５〜１０の重合性単量体が最も好ましい。
【００６７】
上記重合性単量体が５以上の重合性基を持つことにより、重合性基を有する電荷輸送性化合物との反応性が促進され、本発明の硬化膜に十分な電荷輸送性を付与することができ、良好な感度や帯電特性を本発明の有機感光体に付与することができる。一方、重合性基が１０より多いと硬化膜中に残存する重合性基が多く成りやすく、残留電位を増加させやすい。
【００６８】
電荷輸送層或いは表面保護層のいずれの場合も、重合性基を有する電荷輸送性化合物及び重合性基を有するシリカを含有する硬化性組成物を塗布液とし、該塗布液を導電性支持体上に塗布後、反応させるのが好ましいが、前もって、該硬化性組成物中で反応を進行させ、反応が進行した硬化性組成物を塗布液とし、該塗布液を導電性支持体上に塗布乾燥させて硬化膜を形成してもよい。
【００６９】
上記硬化性組成物には、重合性基を有する電荷輸送性化合物及び重合性基を有するシリカ以外に、必要により、重合性単量体、重合開始剤、増感剤、バインダー樹脂、酸化防止剤、紫外線吸収剤、熱重合禁止剤、レべリング剤、フッソ系樹脂粒子等の表面改質粒子及び硬化性組成物中の化合物を溶解、或いは分散できる溶媒が混合される。
【００７０】
これらの溶媒は一般に有機溶媒が用いられるが、必要により、有機溶媒同士の混合溶媒、或いは水と有機溶媒の混合溶媒を用いることも可能である。該有機溶媒としては、メチクロ、エチクロ、クロロホルム、モノクロルベンゼン、ジクロルベンゼン、テトラヒドロフラン、ジオキソラン、ジオキサン、ベンゼン、トルエン、キシレン、メシチレン、アルコール類、エステル類、ヘキサン、ヘプタン、リグロイン、ケロシン、テトラリン、ケトン類、エーテル類、ジメチルホルムアミド、アセトニトリルなどが好ましく使われる。
【００７１】
上記硬化性組成物に混合される重合開始剤としては、前記重合性単量体、重合性基を有する電荷輸送性化合物及び重合性基を有するシリカの重合開始剤としては、ラジカル開始剤が好ましく、例えば以下のような化合物が用いられる。即ち、ＡＤＶＮ（Ａｚｏｂｉｓ−（２，４−ｄｉｍｅｔｈｙｌｖａｌｅｒｏｎｉｔｒｉｌｅ））、ＡＩＢＮ（Ａｚｏｂｉｓｉｓｏｂｕｔｙｒｏｎｉｔｒｉｌｅ）、ＡＣＰＡ（Ａｚｏｂｉｓ−（４−ｃｙａｎｏｐｅｎｔａｎｏｉｃ ａｃｉｄ））、ＡＭＢＮ（Ａｚｏｂｉｓ−（２−ｍｅｔｈｙｌｂｕｔｙｒｏｎｉｔｒｉｌｅ））、ＢＰＯ（Ｂｅｎｚｏｙｌ ｐｅｒｏｘｉｄｅ）などが好ましく用いられる。また、放射線重合開始剤の具体例を示すと、１−ヒドロキシシクロへキシルフェニルケトン、２，２−ジエトキシアセトフェノン、２，２−ジメトキシ−２−フェニルアセトフェノン、キサントン、フルオレノン、ベンズアルデヒド、フルオレン、アントラキノン、カルバゾール、３−メチルアセトフェノン、４−クロロアセトフェノン、４，４’−ジメトキシアセトフェノン、４，４’−ジアミノベンゾフェノン、ミヒラーケトン、ベンゾインプロピルエーテル、ベンゾイルエチルエーテル、ベンジルジメチルケタール、１−（４−イソプロピルフェニル）−２−ヒドロキシ−メチルプロパン−１−オン、２−ヒドロキシ−２−メチル−１−フェニルプロパン−１−オン、チオキサントン、ジエチルチオキサントン、２−イソプロピルチオキサントン、２−クロロチオキサントン、２−メチル−１−［４−（メチルチオ）フェニル］−２−モルホリノプロパン−１−オン、２，４，６−トリメチルベンゾイルジフェニルフォスフィンオキシド等が挙げられる。また、市販品としては、Ｉｒｕｇａｃｕｒｅ１８４，６５１，５００，９０７，ＣＧ１１３６９，ＣＧ２４−６１（以上、チバガイギー（株）製）およびＬＵＣＩＲＩＮＥ ＬＳ８７２８（以上、ＢＡＳＦ（株）製）、ユベクリルＰ３６（ＵＣＢ（株）製）およびＶＩＣＵＲＥ５５（アクゾ（株）製）等を挙げることができる。
【００７２】
また、本発明においてはこれら放射線重合開始剤とともに増感剤を併用してもよく、この増感剤としては、例えばトリエチルアミン、ジエチルアミン、Ｎ−メチルジエタノールアミン、エタノールアミン、４−ジメチルアミノ安息香酸、４−ジメチルアミノ安息香酸イソアミル等が挙げられる。また、市販品としては、ユベクリルＰ１０２、１０３、１０４、１０５（以上、ＵＣＢ（株）製）等が挙げられる。これら増感剤の添加剤は、前記放射線重合開始剤１００質量部に対し、通常１〜５００質量部である。
【００７３】
酸化防止剤としては、ＩＲＵＧＡＮＯＸ１０１０、１０３５、１０７６、１２２２（以上、チバガイギー（株）製）等、紫外線吸収剤としては、ＴＩＮＵＶＩＮＮ Ｐ２３４、３２０、３２６、３２７、３２８、２１３、３２９（以上、チバガイギー（株）製）、ＳＥＥＳＯＲＢ１０２、１０３、５０１、２０２、７１２（以上、シプロ化成（株）製）等を挙げることができる。
【００７４】
硬化性組成物（塗布液）について説明する。
本発明の重合性基を有するシリカは、（ｂ）シリカ粒子すなわち粉体状シリカあるいはコロイダルシリカに対し、（ａ）重合性基を有する加水分解性シランがシリルオキシ基を介して化学的に結合して形成される。すなわち、前記重合性基を有する加水分解性シランが有する加水分解性シリル基が加水分解性反応によりシリカ粒子との間にシリルオキシ基を生成し、化学的に結合し、固着する。シリカ粒子中の重合性基を有する加水分解性シランの固着量（シリカ粒子表面に存在する水酸基数をベースにして）は、０．０５〜９９質量％、好ましくは５〜８５質量％である。固着量が０．０５質量％未満の場合、硬化性組成物から形成された硬化膜の耐摩耗性が不十分で、耐久性が長い有機感光体が得られない。一方、９９質量％を超えた場合、硬化膜中に未反応の重合性基が多数残存する傾向にあり、電子写真特性（感度や帯電性）が劣化しやすい。
【００７５】
本発明においては、本発明の重合性基を有するシリカおよび重合性基を有する電荷輸送性化合物を含有することを特徴とする硬化性組成物が提供される。重合性基を有する電荷輸送性化合物としては、前記した重合性基を有する電荷輸送性化合物を用いることができる。
【００７６】
重合性基を有する電荷輸送性化合物の配合量は、重合性基を有するシリカの固形分１００質量部に対し、通常５〜２０００質量部、好ましくは１０から１０００質量部、更に好ましくは２０〜１００質量部である。５質量部未満では電荷輸送性が不足する傾向があり、一方、２０００質量部を越えると、硬化膜の耐摩耗特性が低下したり、塗布性が低下する傾向がある。
【００７７】
又、硬化性組成物中に重合性単量体を加える場合は、重合性単量体の配合量は、重合性基を有するシリカの固形分１００質量部に対し、通常５〜２０００質量部、好ましくは１０から１０００質量部、更に好ましくは１００〜８００質量部である。５質量部未満では硬化膜の耐摩耗度が不足し、電子写真特性（感度や耐電特性）が劣化する傾向があり、一方、２０００質量部を越えても電子写真特性が低下する傾向がある。
【００７８】
本発明の硬化性組成物は熱および／または放射線によって硬化される。上記放射線照射により活性ラジカル種を発生させる化合物は、好ましくは紫外線照射により活性ラジカル種を発生させる化合物から選ばれ、硬化性組成物の固形分１００質量部に対し０．１〜２０質量部配合され、好ましくは１〜５質量部配合される。０．１質量部未満の場合反応速度が遅く、２０質量部を超えると経済的でない。
【００７９】
上記硬化性組成物を導電性支持体上に塗布した後には、１秒〜７２時間、好ましくは５秒〜２４時間、さらに好ましくは５秒〜１時間の範囲内で、０℃〜２００℃、好ましくは１０℃〜１００℃で揮発成分を乾燥させた後、熱又は放射線（両方を併用してもよい）で硬化処理を行うことにより硬化膜を得ることができる。熱による硬化を実施する場合の好ましい乾燥条件は２０℃〜１５０℃であり、１０秒〜１時間の範囲内で行われる。放射線を用いて本発明の硬化性組成物を硬化せしめる場合、好ましくは紫外線又は電子線を用いる。このような場合、好ましい紫外線の照射光量は０．０１〜１０Ｊ／ｃｍ^２であり、より好ましくは０．１〜２Ｊ／ｃｍ^２である。また、好ましい電子線の照射条件は、加圧電圧は１０〜３００ｋＶ、電子密度は０．０２〜０．３０ｍＡ／ｃｍ^２であり、電子線照射量は１〜１０Ｍｒａｄである。
【００８０】
次に、本発明の有機感光体の構成について記載する。
本発明の硬化膜は、有機感光体の表面層を形成する電荷輸送層、或いは表面保護層等に適用することが好ましい。以下、本発明の硬化膜を用いた有機感光体を中心に説明する。
【００８１】
本発明において、有機感光体とは電子写真感光体の構成に必要不可欠な電荷発生機能及び電荷輸送機能のいずれか一方の機能を有機化合物に持たせて構成された電子写真感光体を意味し、公知の有機電荷発生物質又は有機電荷輸送物質から構成された感光体、電荷発生機能と電荷輸送機能を高分子錯体で構成した感光体等公知の有機電子写真感光体を全て含有する。
【００８２】
有機感光体の層構成は、特に限定はないが、電荷発生層、電荷輸送層、或いは電荷発生・電荷輸送層（電荷発生と電荷輸送の機能を同一層に有する層）等の感光層とその上に必要により、表面保護層を塗設した構成をとるのが好ましい。
【００８３】
導電性支持体
本発明の感光体に用いられる導電性支持体としてはシート状、円筒状のどちらを用いても良いが、画像形成装置をコンパクトに設計するためには円筒状導電性支持体の方が好ましい。
【００８４】
円筒状導電性支持体とは回転することによりエンドレスに画像を形成できるに必要な円筒状の支持体を意味し、真直度で０．１ｍｍ以下、振れ０．１ｍｍ以下の範囲にある導電性の支持体が好ましい。この真円度及び振れの範囲を超えると、良好な画像形成が困難になる。
【００８５】
導電性の材料としてはアルミニウム、ニッケルなどの金属ドラム、又はアルミニウム、酸化錫、酸化インジュウムなどを蒸着したプラスチックドラム、又は導電性物質を塗布した紙・プラスチックドラムを使用することができる。導電性支持体としては常温で比抵抗１０^３Ωｃｍ以下が好ましい。
【００８６】
本発明で用いられる導電性支持体は、その表面に封孔処理されたアルマイト膜が形成されたものを用いても良い。アルマイト処理は、通常例えばクロム酸、硫酸、シュウ酸、リン酸、硼酸、スルファミン酸等の酸性浴中で行われるが、硫酸中での陽極酸化処理が最も好ましい結果を与える。硫酸中での陽極酸化処理の場合、硫酸濃度は１００〜２００ｇ／Ｌ、アルミニウムイオン濃度は１〜１０ｇ／Ｌ、液温は２０℃前後、印加電圧は約２０Ｖで行うのが好ましいが、これに限定されるものではない。又、陽極酸化被膜の平均膜厚は、通常２０μｍ以下、特に１０μｍ以下が好ましい。
【００８７】
中間層
本発明においては導電性支持体と感光層の間に、バリヤー機能を備えた中間層を設けることもできる。
【００８８】
本発明においては導電性支持体と前記感光層のとの接着性改良、或いは該支持体からの電荷注入を防止するために、該支持体と前記感光層の間に中間層（下引層も含む）を設けることもできる。該中間層の材料としては、ポリアミド樹脂、塩化ビニル樹脂、酢酸ビニル樹脂並びに、これらの樹脂の繰り返し単位のうちの２つ以上を含む共重合体樹脂が挙げられる。これら下引き樹脂の中で繰り返し使用に伴う残留電位増加を小さくできる樹脂としてはポリアミド樹脂が好ましい。又、これら樹脂を用いた中間層の膜厚は０．０１〜０．５μｍが好ましい。
【００８９】
又本発明に好ましく用いられる中間層はシランカップリング剤、チタンカップリング剤等の有機金属化合物を熱硬化させた硬化性金属樹脂を用いた中間層が挙げられる。硬化性金属樹脂を用いた中間層の膜厚は、０．１〜２μｍが好ましい。
【００９０】
又、本発明に好ましく用いられる中間層としては疎水化表面処理を行った酸化チタン微粒子（平均粒径が０．０１〜１μｍ）をポリアミド樹脂等のバインダーに分散させた中間層が挙げられる。該中間層の膜厚は、１〜１５μｍが好ましい。
【００９１】
感光層
本発明の感光体の感光層構成は前記中間層上に電荷発生機能と電荷輸送機能を１つの層に持たせた単層構造の感光層構成でも良いが、より好ましくは感光層の機能を電荷発生層（ＣＧＬ）と電荷輸送層（ＣＴＬ）に分離した構成をとるのがよい。機能を分離した構成を取ることにより繰り返し使用に伴う残留電位増加を小さく制御でき、その他の電子写真特性を目的に合わせて制御しやすい。負帯電用の感光体では中間層の上に電荷発生層（ＣＧＬ）、その上に電荷輸送層（ＣＴＬ）の構成を取ることが好ましい。正帯電用の感光体では前記層構成の順が負帯電用感光体の場合の逆となる。本発明の最も好ましい感光層構成は前記機能分離構造を有する負帯電感光体構成である。
【００９２】
以下に、本発明の硬化膜を表面保護層とした機能分離負帯電感光体の感光層構成について説明する。
【００９３】
電荷発生層
電荷発生層には電荷発生物質（ＣＧＭ）を含有する。その他の物質としては必要によりバインダー樹脂、その他添加剤を含有しても良い。
【００９４】
電荷発生物質（ＣＧＭ）としては公知の電荷発生物質（ＣＧＭ）を用いることができる。例えばフタロシアニン顔料、アゾ顔料、ペリレン顔料、アズレニウム顔料などを用いることができる。これらの中で繰り返し使用に伴う残留電位増加を最も小さくできるＣＧＭは複数の分子間で安定な凝集構造をとりうる立体、電位構造を有するものであり、具体的には特定の結晶構造を有するフタロシアニン顔料、ペリレン顔料のＣＧＭが挙げられる。例えばＣｕ−Ｋα線に対するブラッグ角２θが２７．２°に最大ピークを有するチタニルフタロシアニン、同２θが１２．４に最大ピークを有するベンズイミダゾールペリレン等のＣＧＭは繰り返し使用に伴う劣化がほとんどなく、残留電位増加小さくすることができる。
【００９５】
電荷発生層にＣＧＭの分散媒としてバインダーを用いる場合、バインダーとしては公知の樹脂を用いることができるが、最も好ましい樹脂としてはホルマール樹脂、ブチラール樹脂、シリコーン樹脂、シリコーン変性ブチラール樹脂、フェノキシ樹脂等が挙げられる。バインダー樹脂と電荷発生物質との割合は、バインダー樹脂１００質量部に対し２０〜６００質量部が好ましい。これらの樹脂を用いることにより、繰り返し使用に伴う残留電位増加を最も小さくできる。電荷発生層の膜厚は０．０１μｍ〜２μｍが好ましい。
【００９６】
電荷輸送層
電荷輸送層には電荷輸送物質（ＣＴＭ）及びＣＴＭを分散し製膜するバインダー樹脂を含有する。
【００９７】
電荷輸送物質（ＣＴＭ）としては公知の電荷輸送物質（ＣＴＭ）を用いることができる。例えばトリフェニルアミン誘導体、ヒドラゾン化合物、スチリル化合物、ベンジジン化合物、ブタジエン化合物などを用いることができる。これら電荷輸送物質は通常、適当なバインダー樹脂中に溶解して層形成が行われる。これらの中で繰り返し使用に伴う残留電位増加を最も小さくできるＣＴＭは高移動度で、且つ組み合わされるＣＧＭとのイオン化ポテンシャル差が０．５（ｅＶ）以下の特性を有するものであり、好ましくは０．２５（ｅＶ）以下である。
【００９８】
ＣＧＭ、ＣＴＭのイオン化ポテンシャルは表面分析装置ＡＣ−１（理研計器社製）で測定される。
【００９９】
電荷輸送層（ＣＴＬ）に用いられるバインダー樹脂としては、例えばポリスチレン、アクリル樹脂、メタクリル樹脂、塩化ビニル樹脂、酢酸ビニル樹脂、ポリビニルブチラール樹脂、エポキシ樹脂、ポリウレタン樹脂、フェノール樹脂、ポリエステル樹脂、アルキッド樹脂、ポリカーボネート樹脂、シリコーン樹脂、メラミン樹脂並びに、これらの樹脂の繰り返し単位のうちの２つ以上を含む共重合体樹脂とうが挙げられる。又、ポリ−Ｎ−ビニルカルバゾール等の高分子有機半導体が挙げられる。特にポリカーボネートが電子写真特性（帯電性、感度等）を良好に保つ上で好ましい。
【０１００】
表面保護層（表面層）
前記した本発明の硬化膜を表面保護層として用いる。即ち、本発明の硬化性蘇生物をそのまま表面保護層用塗布液として用い、該塗布液を塗布、乾燥して重合反応を進行させ、表面保護層を形成してもよいし、又上記塗布液に電荷輸送物質、酸化防止剤、塗布助剤等の添加剤を加えて調製し、表面保護層用塗布液を作製して、塗布乾燥し、重合反応を進行させ、表面保護層を形成してもよい。
【０１０１】
中間層、感光層等の層形成に用いられる溶媒又は分散媒としては、ｎ−ブチルアミン、ジエチルアミン、エチレンジアミン、イソプロパノールアミン、トリエタノールアミン、トリエチレンジアミン、Ｎ，Ｎ−ジメチルホルムアミド、アセトン、メチルエチルケトン、メチルイソプロピルケトン、シクロヘキサノン、ベンゼン、トルエン、キシレン、クロロホルム、ジクロロメタン、１，２−ジクロロエタン、１，２−ジクロロプロパン、１，１，２−トリクロロエタン、１，１，１−トリクロロエタン、トリクロロエチレン、テトラクロロエタン、テトラヒドロフラン、ジオキソラン、ジオキサン、メタノール、エタノール、ブタノール、イソプロパノール、酢酸エチル、酢酸ブチル、ジメチルスルホキシド、メチルセロソルブ等が挙げられる。本発明はこれらに限定されるものではないが、ジクロロメタン、１，２−ジクロロエタン、メチルエチルケトン等が好ましく用いられる。また、これらの溶媒は単独或いは２種以上の混合溶媒として用いることもできる。
【０１０２】
次に本発明の電子写真感光体を製造するための塗布加工方法としては、浸漬塗布、スプレー塗布、円形量規制型塗布等の塗布加工法が用いられるが、感光層の上層側の塗布加工は下層の膜を極力溶解させないため、又、均一塗布加工を達成するためスプレー塗布又は円形量規制型（円形スライドホッパ型がその代表例）塗布等の塗布加工方法を用いるのが好ましい。なお本発明の樹脂層は前記円形量規制型塗布加工方法を用いるのが最も好ましい。前記円形量規制型塗布については例えば特開昭５８−１８９０６１号公報に詳細に記載されている。
【０１０３】
次に、本発明の画像形成装置について説明する。
図１は本発明の画像形成方法の１例としての画像形成装置の断面図である。
【０１０４】
図１に於いて５０は像担持体である感光体ドラム（感光体）で、有機感光層をドラム上に塗布し、その上に本発明の硬化膜を塗設した感光体で、接地されて時計方向に駆動回転される。５２はスコロトロンの帯電器（帯電手段）で、感光体ドラム５０周面に対し一様な帯電をコロナ放電によって与えられる。この帯電器５２による帯電に先だって、前画像形成での感光体の履歴をなくすために発光ダイオード等を用いた帯電前露光部５１による露光を行って感光体周面の除電をしてもよい。
【０１０５】
感光体への一様帯電の後、像露光手段としての像露光器５３により画像信号に基づいた像露光が行われる。この図の像露光器５３は図示しないレーザーダイオードを露光光源とする。回転するポリゴンミラー５３１、ｆθレンズ等を経て反射ミラー５３２により光路を曲げられた光により感光体ドラム上の走査がなされ、静電潜像が形成される。
【０１０６】
ここで反転現像プロセスとは帯電器５２により、感光体表面を一様に帯電し、像露光が行われた領域、即ち感光体の露光部電位（露光部領域）を現像工程（手段）により、顕像化する画像形成方法である。一方未露光部電位は現像スリーブ５４１に印加される現像バイアス電位により現像されない。
【０１０７】
その静電潜像は次いで現像手段としての現像器５４で現像される。感光体ドラム５０周縁にはトナーとキャリアとから成る現像剤を内蔵した現像器５４が設けられていて、マグネットを内蔵し現像剤を保持して回転する現像スリーブ５４１によって現像が行われる。現像器５４内部は現像剤攪拌搬送部材５４４、５４３、搬送量規制部材５４２等から構成されており、現像剤は攪拌、搬送されて現像スリーブに供給されるが、その供給量は該搬送量規制部材５４２により制御される。該現像剤の搬送量は適用される有機電子写真感光体の線速及び現像剤比重によっても異なるが、一般的には２０〜２００ｍｇ／ｃｍ^２の範囲である。
【０１０８】
現像剤は、例えばフェライトをコアとしてそのまわりに絶縁性樹脂をコーティングしたキャリアと、スチレンアクリル系樹脂を主材料としてカーボンブラック等の着色剤と荷電制御剤と低分子量ポリオレフィンからなる着色粒子に、シリカ、酸化チタン等を外添したトナーとからなるもので、現像剤は搬送量規制部材によって層厚を規制されて現像域へと搬送され、現像が行われる。この時通常は感光体ドラム５０と現像スリーブ５４１の間に直流バイアス、必要に応じて交流バイアス電圧をかけて現像が行われる。また、現像剤は感光体に対して接触あるいは非接触の状態で現像される。感光体の電位測定は電位センサー５４７を図１のように現像位置上部に設けて行う。
【０１０９】
記録紙Ｐは画像形成後、転写のタイミングの整った時点で給紙ローラー５７の回転作動により転写域へと給紙される。
【０１１０】
転写域においては転写のタイミングに同期して感光体ドラム５０の周面に転写電極（転写手段：転写器）５８が作動し、給紙された記録紙Ｐにトナーと反対極性の帯電を与えてトナーを転写する。
【０１１１】
次いで記録紙Ｐは分離電極（分離器）５９によって除電がなされ、感光体ドラム５０の周面により分離して定着装置６０に搬送され、熱ローラー６０１と圧着ローラー６０２の加熱、加圧によってトナーを溶着したのち排紙ローラー６１を介して装置外部に排出される。なお前記の転写電極５８及び分離電極５９は記録紙Ｐの通過後、一次作動を中止し、次なるトナー像の形成に備える。図１では転写電極５８にコロトロンの転写帯電極を用いている。転写電極の設定条件としては、感光体のプロセススピード（周速）等により異なり一概に規定することはできないが、例えば、転写電流としては＋１００〜＋４００μＡ、転写電圧としては＋５００〜＋２０００Ｖを設定値とすることができる。
【０１１２】
一方記録紙Ｐを分離した後の感光体ドラム５０は、クリーニング器（クリーニング手段）６２のブレード６２１の圧接により残留トナーを除去・清掃し、再び帯電前露光部５１による除電と帯電器５２による帯電を受けて次なる画像形成のプロセスに入る。
【０１１３】
尚、７０は感光体、帯電器、転写器、分離器及びクリーニング器が一体化されている着脱可能なプロセスカートリッジである。
【０１１４】
本発明の有機電子写真感光体は電子写真複写機、レーザープリンター、ＬＥＤプリンター及び液晶シャッター式プリンター等の電子写真装置一般に適応するが、更に、電子写真技術を応用したディスプレー、記録、軽印刷、製版及びファクシミリ等の装置にも幅広く適用することができる。
【０１１５】
【実施例】
以下実施例をあげて詳細な説明を行うが、本発明はこれらに限定されるものではない。尚、文中の「部」は質量部を表す。
【０１１６】
感光体１の作製
下記のようにして感光体１を作製した。
【０１１７】
〈中間層〉
ポリアミド樹脂「ＣＭ８０００」（東レ社製） １０．０部
酸化チタン「ＳＭＴ５００ＳＡＳ」（テイカ社製） ３０．０部
メタノール １００．０部
上記の成分を循環式湿式分散機（デイスパーマットＳＬＣ１２ＥＸ；ＶＭＡ ＧＥＴＺＭＡＮＮ社製）を用いて分散し、中間層塗布液を作製した。該中間層塗布液を直径８０ｍｍの円筒形アルミニウム基体上に浸漬塗布して、乾燥膜厚１．５μｍの中間層を形成した。
【０１１８】

上記を混合しサンドグラインダーにて分散し、電荷発生層塗布液を作製し、前記中間層上に該電荷発生層塗布液を浸漬塗布して、乾燥膜厚０．３μｍの電荷発生層を形成した。
【０１１９】

上記成分を混合溶解し電荷輸送層塗布液を作製した。該電荷輸送層塗布液を前記電荷発生層上に円形スライドホッパ型塗布機を用いて塗布し、乾燥膜厚２０μｍの電荷輸送層を形成した。
【０１２０】
〈表面保護層〉
重合性基を有する加水分解性シラン（ＪＳ−１）を１０部、コロイダルシリカ（数平均一次粒径３５ｎｍ）を固形分で３０部及びｔ−ブチルアルコール３００部の混合物を加熱して５分還流し、重合性基を有するシリカを含む組成物を作製した。該組成物を冷却後、重合性単量体（Ｍ−１）２５部、重合開始剤（２，２−ジエトキシアセトフェノン）３部、重合性基を有する電荷輸送性化合物（ＣＴＭＲ−２１）を４０部加え、この硬化性組成物（塗布液）を電荷輸送層上に塗布し、乾燥後、高圧水銀灯にて８０ｍＷ／ｃｍ^２の光強度で３０秒間紫外線照射して、膜厚３．０μｍの表面保護層を形成し、感光体１を作製した。
【０１２１】
感光体２〜７の作製
感光体１の作製において、表面保護層の塗布液（硬化性組成物）組成を表１のように変えた以外は感光体１と同様にして本発明の硬化膜の表面保護層を有する感光体２〜７を作製した。
【０１２２】
感光体８の作製
感光体１の作製において、表面保護層を下記のようにして形成した以外は同様にして感光体８を作製した。
【０１２３】
〈表面保護層〉
重合性基を有する加水分解性シラン（ＪＳ−１）を１０部、コロイダルシリカ（数平均一次粒径１５ｎｍ）を固形分で３０部及びｔ−ブチルアルコール３００部の混合物を加熱して５分還流し、重合性基を有するシリカを含む組成物を作製した。該組成物を冷却後、重合開始剤（２，２−ジエトキシアセトフェノン）３部、重合性基を有する電荷輸送性化合物（ＣＴＭＲ−４２）を６５部加え、この硬化性組成物（塗布液）を電荷輸送層上に塗布し、乾燥後、高圧水銀灯にて８０ｍＷ／ｃｍ^２の光強度で３０秒間紫外線照射して、膜厚３．０μｍの表面保護層を形成し、感光体８を作製した。
【０１２４】
感光体９の作製（比較用感光体）
感光体１の作製において、表面保護層の塗布液中から重合性基を有する電荷輸送性化合物（ＣＴＭＲ−２１）を除き、重合性単量体をＭ−１からブチレングリコールジアクリレートに代えた以外は感光体１と同様にして比較用の硬化膜の表面保護層を有する感光体９を作製した。
【０１２５】
感光体１０の作製（比較用感光体）
感光体１の作製において、表面保護層の塗布液からコロイダルシリカを除いた他は感光体１と同様にして比較用の硬化膜の表面保護層を有する感光体１０を作製した。
【０１２６】
感光体１１の作製（比較用感光体）
感光体１の作製において、表面保護層を設けないで、電荷輸送層の乾燥膜厚を２５μｍとした以外は、感光体１と同様にして感光体１１を作製した。
【０１２７】
【表１】

【０１２８】
評価
評価機としてコニカ社製デジタル複写機Ｋｏｎｉｃａ「Ｓｉｔｉｏｓ７０７５」（コロナ帯電、レーザー露光、反転現像、静電転写、爪分離、ブレードクリーニング、クリーニング補助ブラシローラー採用プロセスを有し、プリント速度７５枚／ｍｉｎ）を用い、該複写機に感光体１〜１１を搭載し評価した。評価は、画素率が７％の文字画像、人物顔写真、ベタ白画像、ベタ黒画像がそれぞれ１／４等分にあるオリジナル画像をＡ４中性紙に複写して行った。複写条件は高温高湿環境（３０℃、８０％ＲＨ）及び低温低湿環境（１０℃、２０％ＲＨ）にて、各１０万枚のコピーを行いハーフトーン、ベタ白画像、ベタ黒画像を評価した。但し、コピー開始前に、感光体表面にセッティングパウダーをまぶし、感光体とクリーニングブレードをなじませた後コピーを行った。評価項目及び評価基準を下記に示す。
【０１２９】
評価項目及び評価基準
画像濃度（マクベス社製ＲＤ−９１８を使用して測定。紙の反射濃度を「０」とした相対反射濃度で測定した。初期と２０万枚コピー後の両方で評価）
◎：初期と２０万枚コピー後の両方共１．２以上：良好
○：初期と２０万枚コピー後の両方共１．０以上：実用上問題ないレベル
×：初期と２０万枚コピー後の少なくとも一方が１．０未満：実用上問題となるレベル
カブリ（ベタ白画像濃度で判定した。初期と２０万枚コピー後の両方で評価）マクベス社製「ＲＤ−９１８」を用いて、印字されていないコピー用紙（白紙）の濃度を２０カ所、絶対画像濃度で測定し、その平均値を白紙濃度とする。次に、画像形成がなされた評価用紙の白地部分を同様に２０カ所、絶対画像濃度で測定し、その平均濃度から前記白紙濃度を引いた値をカブリ濃度として評価した。
【０１３０】
◎：初期と２０万枚コピー後の両方共０．００５以下（良好）
○：初期と２０万枚コピー後の両方共０．０１以下（実用上問題ないレベル）
×：初期と２０万枚コピー後の少なくとも一方が０．０１より高い（明らかに、実用上問題あり）
画像ボケ
０．１ｍｍ間隔の線で作製された５ｃｍの幅の格子画像を有するオリジナル画像を用いて高温高湿環境（３０℃８０％ＲＨ）及び低温低湿環境（１０℃２０％ＲＨ）にて画像を形成し、画像を２０倍に拡大し、線の鮮鋭性、独立性を観察した。
【０１３１】
◎：画像ボケがなく、各線画像がオリジナル画像の±２０％の範囲で、再現されている（良好）
○：画像ボケが少なく、各線画像がオリジナル画像の±（２１〜４０％）の範囲で、再現されている（実用上問題なし）
△：画像ボケが大きく、各線画像がオリジナル画像の±（４１〜７５％）の範囲で、再現されている（高階調性画質としては不適）
×：画像ボケが著しく、各線画像がオリジナル画像の±７６％以上、又は線間隔がつぶれている（実用上問題あり）
鮮鋭性
画像の鮮鋭性は、低温低湿（１０℃２０％ＲＨ）、高温高湿（３０℃８０％ＲＨ）の両環境において画像を出し、文字潰れで評価した。３ポイント、５ポイントの文字画像を形成し、下記の判断基準で評価した。
【０１３２】
◎：３ポイント、５ポイントとも明瞭であり、容易に判読可能
○：３ポイントは一部判読不能、５ポイントは明瞭であり、容易に判読可能
×：３ポイントは殆ど判読不能、５ポイントも一部あるいは全部が判読不能
膜厚減耗量
減耗量は実写評価開始時と２０万枚コピー終了時に測定した感光層の平均膜厚の差分を求め、膜厚減耗量とした。
【０１３３】
膜厚測定法
感光層の膜厚は均一膜厚部分をランダムに１０ケ所測定し、その平均値を感光層の膜厚とする。膜厚測定器は渦電流方式の膜厚測定器ＥＤＤＹ５６０Ｃ（ＨＥＬＭＵＴ ＦＩＳＣＨＥＲ ＧＭＢＴＥ ＣＯ社製）を用いて行い、実写試験前後の感光層膜厚の差を膜厚減耗量とする。
【０１３４】
その他評価条件
尚、前記Ｓｉｔｉｏｓ７０７５を用いたその他の評価条件は下記の条件に設定した。
【０１３５】
帯電条件
帯電器；スコロトロン帯電器、初期帯電電位を−７５０Ｖ
露光条件
露光部電位を−５０〜−１５０Ｖにする露光量に設定
現像条件
ＤＣバイアス；−５５０Ｖ
現像剤は、フェライトをコアとして絶縁性樹脂をコーティングしたキャリアとスチレンアクリル系樹脂を主材料としてカーボンブラック等の着色剤と荷電制御剤と低分子量ポリオレフィンを含有する体積平均粒径５μｍの着色粒子に、シリカ、酸化チタン等を外添したトナーを用いた現像剤を使用
転写条件
転写極；コロナ帯電方式
クリーニング条件
クリーニング部に硬度７０°、反発弾性６５％、厚さ２（ｍｍ）、自由長９ｍｍのクリーニングブレードをカウンター方向に線圧１８（Ｎ／ｍ）となるように重り荷重方式で当接した。
【０１３６】
評価結果を表２に示した。
【０１３７】
【表２】

【０１３８】
表２から明らかなように、本発明の硬化膜の表面層を有する感光体１〜８は画像濃度、カブリ等の良好な電子写真特性を示し、且つ画像ボケも小さく、良好な鮮鋭性を示し、膜厚減耗量も小さい。特に、感光体１〜６の１個の重合性基を有する電荷輸送性化合物を用いた組み合わせ１〜６は全評価項目において、優れた評価結果を達成している。一方、表面層に重合性基を有する電荷輸送性化合物を含まない感光体９は画像濃度、画像ボケの評価が劣り、その結果鮮鋭性が劣化している。シリカを含有しない感光体１０では、膜厚減耗量が増加し、その結果画像濃度が低下し、鮮鋭性が劣化している。表面保護層を有しない感光体１１も感光体１０と同様の傾向を示している。
【０１３９】
【発明の効果】
実施例からも明らかなように、本発明の構成を用いることにより、電子写真感光体を用いることにより、電子写真特性、画像ボケ、鮮鋭性が改良され、高画質、高耐久の有機感光体を提供することができる。又、該有機感光体の製造方法、有機感光体を用いた良好な電子写真画像を達成できる画像形成方法、画像形成装置及びプロセスカートリッジを提供する事が出来る。
【図面の簡単な説明】
【図１】本発明の画像形成方法の１例としての画像形成装置の断面図。
【符号の説明】
５０ 感光体ドラム（又は感光体）
５１ 帯電前露光部
５２ 帯電器
５３ 像露光器
５４ 現像器
５４１ 現像スリーブ
５４３，５４４ 現像剤攪拌搬送部材
５４７ 電位センサー
５７ 給紙ローラー
５８ 転写電極
５９ 分離電極（分離器）
６０ 定着装置
６１ 排紙ローラー
６２ クリーニング器
７０ プロセスカートリッジ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an organic photoreceptor used in the field of copiers and printers, a method for manufacturing an organic photoreceptor, a process cartridge, an image forming apparatus, and an image forming method.
[0002]
[Prior art]
Electrophotographic image forming methods are roughly classified into analog image forming using a halogen lamp as a light source and digital image forming using an LED or laser as a light source. Recently, digital latent image forming systems have become the mainstream as printers for personal computers and also in ordinary copying machines because of the ease of image processing and the ease of developing them in multifunction machines.
[0003]
In digital image formation, not only copying but also use for producing an original image are increasing, and digital electrophotographic image formation tends to require higher image quality.
[0004]
As the electrophotographic photosensitive member used in the digital system, an organic photosensitive member containing an organic photoconductive substance is most widely used. Organic photoreceptors have advantages over other photoreceptors, such as easy development of materials for various exposure light sources from visible light to infrared light, selection of materials that do not cause environmental pollution, and low manufacturing costs. However, the mechanical strength is weak, and the photoreceptor surface is likely to be deteriorated or damaged during copying or printing a large number of sheets.
[0005]
The layer constitution of the organic photoreceptor is a layer constitution of function separation that balances electrophotographic characteristics (such as charging ability and sensitivity) and mechanical strength, that is, a charge generation layer and a charge transport layer on a conductive support. Laminated layer configurations are widely employed. However, the surface layer of the organic photoreceptor is a resin layer formed from a binder resin such as a polycarbonate resin or an acrylic resin, and has a problem in abrasion resistance and scratch resistance of the surface layer during repeated use.
[0006]
In addition, due to recent demands for higher sensitivity, low-molecular-weight compounds such as charge-transporting substances are often added to the surface layer in a relatively large amount. Is remarkably reduced, so that wear and scratches on the surface layer during repeated use have become a more remarkable problem.
[0007]
As an approach for solving the above-mentioned problem, a photoconductor in which a surface layer contains a fluororesin powder has been reported (Patent Document 1). However, sufficient surface strength cannot be obtained with fluororesin powder, and image blur occurs under high-temperature and high-humidity conditions, and the problem that sharpness is deteriorated has not been sufficiently solved.
There is a problem that a streak failure due to a scratch on the photoreceptor surface is likely to occur.
[0008]
Further, as another prior art, a charge transport layer contains a monomer having a carbon-carbon double bond, and the carbon-carbon double bond of the charge transport material is reacted by heat or light energy to form a charge transport layer. (Japanese Patent Application Laid-Open Nos. H11-27115 and H11-216566) disclose an electrophotographic photoreceptor on which is formed.
[0009]
However, in the reaction between the polymerizable monomer and the charge transport material having a polymerizable group disclosed in these patents, the reaction rate of the polymerizable monomer and the reaction rate of the charge transport material having a polymerizable group are large. In contrast, the cured film formed by these reactions cannot achieve a micro-mixed state of the resin component formed from the polymerizable monomer and the charge transport material component having a polymerizable group, and the mechanical strength is improved. However, the electrophotographic characteristics (charging ability, sensitivity, residual potential, etc.) are not sufficiently improved.
[0010]
[Patent Document 1]
JP-A-63-56658
[Patent Document 2]
JP-A-5-216249
[Patent Document 3]
JP 2000-66424 A
[Problems to be solved by the invention]
An object of the present invention is to solve the problems of conventional organic photoreceptors, to provide an organic photoreceptor having improved abrasion resistance by increasing the film strength, and having good deposition resistance. It is in.
[0014]
Another object of the present invention is to provide an organic photoreceptor which exhibits very little change or deterioration in photoreceptor characteristics such as an increase in residual potential during repeated use and can exhibit stable performance even during repeated use. It is in.
[0015]
Another object of the present invention is to provide an organic photoreceptor which prevents image blurring and has good sharpness.
[0016]
Still another object of the present invention is to provide a process cartridge having the above-mentioned organic photoreceptor, an image forming method and an image forming apparatus.
[0017]
Still another object of the present invention is to provide a method for producing the above-mentioned organic photoreceptor.
[0018]
[Means for Solving the Problems]
That is, the object of the present invention is to form a cured film forming a surface layer of an organic photoreceptor, and interpose silica having a polymerizable group in a polymerization reaction system using a charge transporting compound having a polymerizable group. Thereby, by reacting a charge transporting compound having a polymerizable group with silica having a polymerizable group, it was found that the electrophotographic properties of the cured film and the film strength were improved, and the present invention was completed. . That is, the present invention is achieved by having the following configurations.
[0019]
1. In an organic photoreceptor having a photosensitive layer on a conductive support, the photosensitive layer has a cured film formed from a curable composition containing a charge transporting compound having a polymerizable group and silica having a polymerizable group. An organic photoreceptor, characterized in that:
[0020]
2. 2. The organic photoreceptor according to the item 1, wherein the silica having a polymerizable group is a silica surface-treated with a hydrolyzable silane having a polymerizable group.
[0021]
3. 3. The organic photoconductor according to item 2, wherein the hydrolyzable silane having a polymerizable group is a compound having a carbon-carbon double bond.
[0022]
4. 4. The organic photoreceptor according to any one of the items 1 to 3, wherein the charge transporting compound having a polymerizable group has one polymerizable group.
[0023]
5. In an organic photoreceptor having a photosensitive layer on a conductive support, the surface layer of the organic photoreceptor was formed from a curable composition containing a charge transporting compound having a polymerizable group and silica having a polymerizable group. An organic photoreceptor, which is a cured film.
[0024]
6. In a method for producing an organic photoreceptor having a photosensitive layer on a conductive support, a charge-transporting compound having a polymerizable group and a curable composition containing silica having a polymerizable group are coated on the conductive support. A method for producing an organic photoreceptor, comprising: forming a cured film by heating.
[0025]
7. Organic photosensitive body having a photosensitive layer on a conductive support, wherein the photosensitive layer has a cured film formed from a curable composition containing a charge transporting compound having a polymerizable group and silica having a polymerizable group. Charging means for uniformly charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, and developing for visualizing the electrostatic latent image on the organic photoreceptor Means, transfer means for transferring a toner image visualized on the organic photoreceptor onto a transfer material, charge removing means for removing charge on the organic photoreceptor after transfer, and transfer on the organic photoreceptor after transfer A process cartridge, wherein at least one of cleaning means for removing residual toner is integrally supported, and is detachably mountable to an image forming apparatus main body.
[0026]
8. An image forming apparatus comprising the process cartridge according to the above item 7.
[0027]
9. An image forming method, wherein an electrophotographic image is formed using the image forming apparatus according to the above item 8.
[0028]
Hereinafter, the present invention will be described in detail.
Polymerization in the present invention refers to the former polymerization reaction form of polymerization, in which the production reaction of a polymer substance is largely divided into chain polymerization and sequential polymerization, and the form mainly reacts via intermediates such as radicals or ions. Progress, such as unsaturated polymerization, ring-opening polymerization, and isomerization polymerization.
[0029]
The charge transporting compound having a polymerizable group of the present invention refers to an unsaturated polymerizable group, a ring-opening polymerizable group or an isomerizable polymerizable group in which the reaction proceeds by radical polymerization or ionic polymerization in the charge transporting compound structure. Having compounds. Here, the charge transporting compound structure refers to an unsaturated polymerizable group, a ring-opening polymerizable group, and an isomerizable polymerizable group of a compound having an unsaturated polymerizable group, a ring-opening polymerizable group, and an isomerizable polymerizable group. A compound having a structure in which a hydrogen atom is substituted has a charge transporting ability.
[0030]
Specifically, examples of the charge transporting compound having a polymerizable group of the present invention include a charge transporting compound having a polymerizable double bond of carbon-carbon at a terminal as a polymerizable group. The number of the polymerizable groups may be one or more in the same molecule, but is preferably 1 to 4, and most preferably 1. When the number of polymerizable groups in the charge transporting compound increases, the charge transporting compound structure is incorporated in the resin structure of the cured film with a structure having a small degree of freedom, and the charge transporting property of the cured film is reduced, resulting in a decrease in sensitivity or residual. It is easy to cause potential rise.
[0031]
Hereinafter, specific examples of the charge transporting compound having a polymerizable group used in the present invention will be shown.
[0032]
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[0033]
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[0034]
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[0035]
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[0036]
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[0037]
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[0038]
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[0039]
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[0040]
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[0041]
The silica having a polymerizable group of the present invention comprises silica particles and an organic compound chemically bonded to the silica particles, and the organic compound is a polymerizable unsaturated group or a ring-opening polymerizable group, represented by the following formula (1): And a group represented by the following formula (2)
[0042]
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[0043]
Wherein X is selected from —NH—, —O— and —S—, Y is selected from an oxygen atom and a sulfur atom, provided that when X is —O—, Y is a sulfur atom. The silica particles and the organic compound are provided as reactive silica particles (silica having a polymerizable group) bonded to each other through a silyloxy group.
[0044]
Further, according to the present invention, the silica having a polymerizable group of the present invention comprises (a) a hydrolyzable silyl group, a polymerizable group (polymerizable unsaturated group or ring-opening polymerizable group) in the molecule, From a compound containing a group represented by (1) and a group represented by the above formula (2) (hereinafter referred to as “hydrolyzable silane having a polymerizable group”) and (b) powdery silica and colloidal silica A method of mixing with selected silica particles, causing a hydrolysis reaction, and chemically bonding a hydrolyzable silane having a polymerizable unsaturated group (or a ring-opening polymerizable group) to the silica particles represented by the preceding group (b). Manufactured.
[0045]
The average particle diameter of the silica particles is preferably in a range of 10 nm or more and 500 nm or less in number average primary particle diameter, more preferably 10 nm to 200 nm, and particularly preferably 15 nm to 100 nm.
[0046]
The number average primary particle size of the silica particles is, for example, magnified 10,000 times by transmission electron microscopy, randomly observes 100 particles as primary particles, and is measured by image analysis as the number average diameter of Feret diameter. You.
[0047]
The hydrolyzable silane (a) having a polymerizable group used in the method of the present invention includes a hydrolyzable silyl group, a group represented by the above formula (1) and a group represented by the above (2) and a polymerizable group. It contains at least one group (polymerizable unsaturated group or ring-opening polymerizable group) as a constituent. The hydrolyzable silyl group is a component that binds to a silanol group present on the surface of the silica particle by hydrolysis and condensation reaction, and a polymerizable group is chemically cross-linked between molecules through addition polymerization by an active radical species. It is a component that does. The group represented by the above formula (1) and the group represented by the above (2) can be used for directly or other molecular fragments having a hydrolyzable silyl group and a polymerizable group. It is a structural unit that binds through the intermediary, and at the same time, generates an appropriate cohesive force due to hydrogen bonding between molecules, and has the role of generating properties such as excellent mechanical strength, adhesion to the substrate, heat resistance, etc. to the cured tissue. It is estimated to fulfill.
[0048]
Examples of the hydrolyzable silyl group include carboxylate silyl groups such as alkoxysilyl groups, carboxylate silyl groups such as acetoxysilyl groups; halogenated silyl groups such as chlorosilyl groups; aminosilyl groups, oximusilyl groups, hydroxy groups, and the like. Can be mentioned. The definition of the hydrolyzable silyl group includes a compound which forms a silanol group under the condition of using an acid, a base or another catalyst in combination with water. Among these, an alkoxysilyl group is preferred.
[0049]
Further, the group represented by the above formula (1) includes a group represented by the following formula.
[0050]
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[0051]
Furthermore, examples of the polymerizable group include an acryloxy group, a methacryloxy group, a vinyl group, a propenyl group, a butadienyl group, a styryl group, a nitinyl group, a cinnamoyl group, a maleate group, an acrylamide group, and a caprolactan group. . Among these, an acryloxy group can be mentioned as a preferable one.
[0052]
Examples of the hydrolyzable silane compound having a polymerizable group are shown below.
[0053]
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[0054]
Synthesis Example of JS-1 A solution consisting of 221 parts of mercaptopropyltrimethoxysilane and 1 part of dibutyltin dilaurate in dry air was stirred at 50 ° C. for 1 hour while stirring 223 parts of 1,3-bis (isocyanatomethyl) cyclohexane. After that, the mixture was stirred at 70 ° C. for 3 hours. After 555 parts of pentaerythritol triacrylate was added dropwise at 30 ° C. over 1 hour, the mixture was stirred at 60 ° C. for 10 hours to obtain the compound of JS-1.
[0055]
Further, as another type of hydrolyzable silane having a polymerizable group, a silyl acrylate compound as described in JP-A-9-319130 can be mentioned. That is, hydrolyzable silanes having the following polymerizable groups can be mentioned.
[0056]
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[0057]
Cured film formed from a curable composition containing a charge transporting compound having a polymerizable group and silica having a polymerizable group according to the present invention (a dried and solidified film: hereinafter, a cured film according to the present invention) Is also usable as a charge transporting layer because it has charge transporting ability, but is more preferably used as a surface protective layer separate from the charge transporting layer. In this case, since the surface protective layer has a charge transporting ability, it is included in the definition of the photosensitive layer.
[0058]
The curable composition of the present invention may contain a polymerizable monomer in addition to the charge transportable compound having a polymerizable group and the silica having a polymerizable group. The polymerizable monomer is a chain-polymerizable monomer having an unsaturated polymerizable group, a ring-opening polymerizable group, and an isomerizable polymerizable group in which a chain polymerization reaction proceeds in the above unsaturated polymerization, ring-opening polymerization, and the like. Say.
[0059]
Hereinafter, specific examples of the polymerizable monomer preferably used in the invention, including the general formula, are shown below.
[0060]
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[0061]
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[0062]
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[0063]
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[0064]
These compounds are described in JP-A-7-97415 and the like.
Further, examples of the polymerizable monomer include the following compounds.
[0065]
Diethylene glycol diacrylate, triethylene glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate , Tetramethi Acrylic esters such as toluene methacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, or diallyl phthalate, diallyl isophthalate, diallyl malate, diallyl adipate as allyl esters of polycarboxylic acids, Examples include a polyfunctional monomer having a vinyl group such as diallyl diglycolate, diethylene glycol bisallyl carbonate, and triallylic acid triallyl ester, or a polyhydric phenol compound such as bisphenol A and glycidyl acrylate.
[0066]
Among the above polymerizable monomers, a polymerizable monomer having a polymerizable group of 5 or more, preferably 5 to 10 is most preferable.
[0067]
When the polymerizable monomer has 5 or more polymerizable groups, the reactivity with the charge transporting compound having a polymerizable group is promoted, and sufficient charge transporting property is imparted to the cured film of the present invention. And good sensitivity and charging characteristics can be imparted to the organic photoreceptor of the present invention. On the other hand, when the number of the polymerizable groups is more than 10, the number of the polymerizable groups remaining in the cured film tends to increase, and the residual potential tends to increase.
[0068]
In any case of the charge transport layer or the surface protective layer, a curable composition containing a charge transport compound having a polymerizable group and silica having a polymerizable group is used as a coating solution, and the coating solution is coated on a conductive support. It is preferable that the reaction be performed after application to the composition, but in advance, the reaction proceeds in the curable composition, and the curable composition after the reaction is used as a coating solution, and the coating solution is applied and dried on a conductive support. Then, a cured film may be formed.
[0069]
In the curable composition, in addition to the charge transporting compound having a polymerizable group and the silica having a polymerizable group, if necessary, a polymerizable monomer, a polymerization initiator, a sensitizer, a binder resin, an antioxidant In addition, a solvent capable of dissolving or dispersing the compound in the curable composition and the surface modified particles such as an ultraviolet absorber, a thermal polymerization inhibitor, a leveling agent, a fluorine resin particle and the like are mixed.
[0070]
As these solvents, organic solvents are generally used. If necessary, a mixed solvent of organic solvents or a mixed solvent of water and an organic solvent can be used. Examples of the organic solvent include meticlo, eticlo, chloroform, monochlorobenzene, dichlorobenzene, tetrahydrofuran, dioxolan, dioxane, benzene, toluene, xylene, mesitylene, alcohols, esters, hexane, heptane, ligroin, kerosene, tetralin, and ketone. , Ethers, dimethylformamide, acetonitrile and the like are preferably used.
[0071]
As the polymerization initiator to be mixed with the curable composition, the polymerization initiator of the polymerizable monomer, the charge transportable compound having a polymerizable group and the polymerization initiator of silica having a polymerizable group is preferably a radical initiator. For example, the following compounds are used. That is, ADVN (Azobis- (2,4-dimethylvaleronitrile)), AIBN (Azobisisobutyronitrile), ACPA (Azobis- (4-cyanopentanoic acid)), and AMBN (Azobis- (2-methybenzyl), etc. It is preferably used. Specific examples of the radiation polymerization initiator include 1-hydroxycyclohexylphenyl ketone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, and anthraquinone. Carbazole, 3-methylacetophenone, 4-chloroacetophenone, 4,4'-dimethoxyacetophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoinpropyl ether, benzoylethyl ether, benzyldimethylketal, 1- (4-isopropylphenyl ) -2-Hydroxy-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioki Cantonal, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-one, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, and the like. In addition, as commercially available products, Irugacure 184, 651, 500, 907, CG11369, CG24-61 (all manufactured by Ciba Geigy) and LUCIRINE LS8728 (all manufactured by BASF), Jubecryl P36 (manufactured by UCB) ) And VICURE 55 (manufactured by Akzo Corporation).
[0072]
In the present invention, a sensitizer may be used in combination with the radiation polymerization initiator. Examples of the sensitizer include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, -Dimethylamino isoamyl benzoate and the like. Examples of commercially available products include Juvecryl P102, 103, 104, and 105 (all manufactured by UCB Corporation). The additive of these sensitizers is usually 1 to 500 parts by mass based on 100 parts by mass of the radiation polymerization initiator.
[0073]
Antioxidants include IRUGANOX 1010, 1035, 1076, and 1222 (all manufactured by Ciba Geigy), and ultraviolet absorbers include TINUVIN P234, 320, 326, 327, 328, 213, and 329 (all manufactured by Ciba Geigy) )), SEESORB 102, 103, 501, 202, 712 (all manufactured by Cipro Kasei Co., Ltd.) and the like.
[0074]
The curable composition (coating liquid) will be described.
The silica having a polymerizable group of the present invention is obtained by chemically bonding (a) a hydrolyzable silane having a polymerizable group to (b) silica particles, that is, powdery silica or colloidal silica, through a silyloxy group. Formed. That is, the hydrolyzable silyl group of the hydrolyzable silane having a polymerizable group forms a silyloxy group between the silica particles and the hydrolyzable silyl group by a hydrolytic reaction, and is chemically bonded and fixed. The fixed amount of the hydrolyzable silane having a polymerizable group in the silica particles (based on the number of hydroxyl groups present on the surface of the silica particles) is 0.05 to 99% by mass, preferably 5 to 85% by mass. When the amount of fixation is less than 0.05% by mass, the cured film formed from the curable composition has insufficient abrasion resistance, and an organic photoreceptor having long durability cannot be obtained. On the other hand, when the content exceeds 99% by mass, a large number of unreacted polymerizable groups tend to remain in the cured film, and the electrophotographic characteristics (sensitivity and chargeability) are likely to deteriorate.
[0075]
The present invention provides a curable composition comprising the polymerizable group-containing silica and the polymerizable group-containing charge transporting compound of the present invention. As the charge transporting compound having a polymerizable group, the above-described charge transporting compound having a polymerizable group can be used.
[0076]
The compounding amount of the charge transporting compound having a polymerizable group is usually 5 to 2,000 parts by mass, preferably 10 to 1,000 parts by mass, more preferably 20 to 100 parts by mass, based on 100 parts by mass of the solid content of the silica having the polymerizable group. Parts by weight. If the amount is less than 5 parts by mass, the charge transporting property tends to be insufficient. On the other hand, if the amount exceeds 2,000 parts by mass, the abrasion resistance characteristics of the cured film tend to decrease and the coating properties tend to decrease.
[0077]
When a polymerizable monomer is added to the curable composition, the amount of the polymerizable monomer is usually 5 to 2,000 parts by mass, based on 100 parts by mass of the solid content of silica having a polymerizable group. Preferably it is 10 to 1000 parts by mass, more preferably 100 to 800 parts by mass. When the amount is less than 5 parts by mass, the abrasion resistance of the cured film is insufficient, and the electrophotographic characteristics (sensitivity and electric resistance) tend to deteriorate. On the other hand, when the amount exceeds 2,000 parts by mass, the electrophotographic characteristics tend to deteriorate.
[0078]
The curable composition of the present invention is cured by heat and / or radiation. The compound that generates an active radical species upon irradiation with the radiation is preferably selected from compounds that generate an active radical species upon irradiation with ultraviolet rays, and is compounded in an amount of 0.1 to 20 parts by mass based on 100 parts by mass of the solid content of the curable composition. , Preferably 1 to 5 parts by mass. If the amount is less than 0.1 part by mass, the reaction rate is low, and if it exceeds 20 parts by mass, it is not economical.
[0079]
After the curable composition is applied on the conductive support, the temperature is in the range of 1 second to 72 hours, preferably 5 seconds to 24 hours, more preferably 5 seconds to 1 hour, 0 ° C to 200 ° C, Preferably, after the volatile component is dried at 10 ° C to 100 ° C, a cured film can be obtained by performing a curing treatment with heat or radiation (both may be used in combination). The preferred drying conditions for curing by heat are 20 ° C. to 150 ° C., and are performed within the range of 10 seconds to 1 hour. When the curable composition of the present invention is cured using radiation, ultraviolet rays or electron beams are preferably used. In such a case, the irradiation amount of the ultraviolet light is preferably 0.01 to 10 J / cm ² , and more preferably 0.1 to ² J / cm ² . Preferred electron beam irradiation conditions are a pressure voltage of 10 to 300 kV, an electron density of 0.02 to 0.30 mA / cm ² , and an electron beam irradiation amount of 1 to 10 Mrad.
[0080]
Next, the configuration of the organic photoreceptor of the present invention will be described.
The cured film of the present invention is preferably applied to a charge transport layer forming a surface layer of an organic photoreceptor, or a surface protective layer. Hereinafter, an organic photoreceptor using the cured film of the present invention will be mainly described.
[0081]
In the present invention, the organic photoreceptor means an electrophotographic photoreceptor constituted by giving an organic compound one of a charge generation function and a charge transport function indispensable for the configuration of the electrophotographic photoreceptor, It includes all known organic electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating substance or an organic charge transporting substance, and a photoreceptor having a charge generating function and a charge transporting function composed of a polymer complex.
[0082]
The layer constitution of the organic photoreceptor is not particularly limited, but a photosensitive layer such as a charge generation layer, a charge transport layer, or a charge generation / charge transport layer (a layer having the functions of charge generation and charge transport in the same layer) and the like. It is preferable to adopt a configuration in which a surface protective layer is provided if necessary.
[0083]
Conductive Support As the conductive support used in the photoreceptor of the present invention, either a sheet-like or a cylindrical shape may be used. Is more preferred.
[0084]
The cylindrical conductive support means a cylindrical support necessary for forming an image endlessly by rotating, and a conductive material having a straightness of 0.1 mm or less and a runout of 0.1 mm or less. Supports are preferred. Exceeding the ranges of the roundness and the shake make it difficult to form a good image.
[0085]
As the conductive material, a metal drum of aluminum, nickel, or the like, a plastic drum on which aluminum, tin oxide, indium oxide, or the like is deposited, or a paper or plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.
[0086]
The conductive support used in the present invention may have a surface on which a sealed alumite film is formed. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, and sulfamic acid. Anodizing treatment in sulfuric acid gives the most preferable result. In the case of the anodic oxidation treatment in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average thickness of the anodic oxide coating is usually 20 μm or less, particularly preferably 10 μm or less.
[0087]
Intermediate layer In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.
[0088]
In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (an undercoat layer is also provided) between the support and the photosensitive layer. ) Can be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of the repeating units of these resins. Among these undercoating resins, a polyamide resin is preferable as a resin capable of reducing an increase in residual potential due to repeated use. The thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.
[0089]
The intermediate layer preferably used in the present invention includes an intermediate layer using a curable metal resin obtained by thermally curing an organic metal compound such as a silane coupling agent and a titanium coupling agent. The thickness of the intermediate layer using the curable metal resin is preferably 0.1 to 2 μm.
[0090]
The intermediate layer preferably used in the present invention is an intermediate layer in which titanium oxide fine particles (average particle diameter: 0.01 to 1 μm) subjected to a hydrophobic surface treatment are dispersed in a binder such as a polyamide resin. The thickness of the intermediate layer is preferably from 1 to 15 μm.
[0091]
Photosensitive Layer The photosensitive layer of the photoreceptor of the present invention may have a single-layer structure in which a charge generation function and a charge transport function are provided in one layer on the intermediate layer, but more preferably the function of the photosensitive layer Is preferably separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a configuration in which functions are separated, an increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoreceptor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the case of a positively charged photoreceptor, the order of the layer configuration is opposite to that of the negatively charged photoreceptor. The most preferable constitution of the photosensitive layer of the present invention is a constitution of a negatively charged photoreceptor having the function separation structure.
[0092]
Hereinafter, the structure of the photosensitive layer of the functionally separated negatively charged photoreceptor using the cured film of the present invention as a surface protective layer will be described.
[0093]
Charge Generation Layer The charge generation layer contains a charge generation material (CGM). As other substances, a binder resin and other additives may be contained as necessary.
[0094]
As the charge generation material (CGM), a known charge generation material (CGM) can be used. For example, phthalocyanine pigments, azo pigments, perylene pigments, azurenium pigments and the like can be used. Among these, CGM which can minimize the increase in residual potential due to repeated use has a steric and potential structure capable of forming a stable aggregated structure among a plurality of molecules, and specifically, a phthalocyanine having a specific crystal structure And CGM of a perylene pigment. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu-Kα radiation, and benzimidazole perylene having a maximum peak at a 2θ of 12.4 have almost no deterioration due to repeated use, and remain as such. The potential increase can be reduced.
[0095]
In the case where a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder. No. The ratio between the binder resin and the charge generating substance is preferably from 20 to 600 parts by mass per 100 parts by mass of the binder resin. By using these resins, an increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.
[0096]
Charge transport layer The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing the CTM to form a film.
[0097]
As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, butadiene compounds and the like can be used. These charge transporting substances are usually dissolved in a suitable binder resin to form a layer. Among these, the CTM that can minimize the increase in residual potential due to repeated use has a high mobility and an ionization potential difference from the combined CGM of 0.5 (eV) or less, and is preferably 0. .25 (eV) or less.
[0098]
The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).
[0099]
Examples of the binder resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, Examples include polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. Further, a high molecular organic semiconductor such as poly-N-vinyl carbazole may be used. In particular, polycarbonate is preferred for maintaining good electrophotographic properties (such as chargeability and sensitivity).
[0100]
Surface protective layer (surface layer)
The above-described cured film of the present invention is used as a surface protective layer. That is, the curable resuscitation product of the present invention may be used as it is as a coating solution for a surface protection layer, and the coating solution may be applied and dried to allow a polymerization reaction to proceed to form a surface protection layer. Prepared by adding an additive such as a charge transport material, an antioxidant, and a coating aid, to prepare a coating solution for the surface protective layer, apply and dry, and proceed with the polymerization reaction to form a surface protective layer. Is also good.
[0101]
Solvents or dispersion media used for forming layers such as the intermediate layer and the photosensitive layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methylethylketone, and methylisopropyl. Ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, Dioxolan, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve and the like. That. Although the present invention is not limited to these, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone and the like are preferably used. In addition, these solvents can be used alone or as a mixed solvent of two or more kinds.
[0102]
Next, as a coating method for manufacturing the electrophotographic photoreceptor of the present invention, a coating method such as dip coating, spray coating, circular amount control type coating is used. In order not to dissolve the lower layer film as much as possible, and to achieve a uniform coating process, it is preferable to use a coating process method such as spray coating or circular volume control type (a typical example is a circular slide hopper type). It is most preferable that the resin layer of the present invention uses the above-mentioned circular amount-regulated coating method. The circular amount control type coating is described in detail in, for example, JP-A-58-189061.
[0103]
Next, the image forming apparatus of the present invention will be described.
FIG. 1 is a sectional view of an image forming apparatus as an example of the image forming method of the present invention.
[0104]
In FIG. 1, reference numeral 50 denotes a photoreceptor drum (photoreceptor) serving as an image carrier, which is a photoreceptor having an organic photosensitive layer applied on the drum and a cured film of the present invention applied thereon. It is driven and rotated clockwise. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the peripheral surface of the photosensitive drum 50 by corona discharge. Prior to the charging by the charger 52, in order to eliminate the history of the photoconductor in the previous image formation, exposure by the pre-charging exposure unit 51 using a light emitting diode or the like may be performed to remove the charge on the peripheral surface of the photoconductor.
[0105]
After the photosensitive member is uniformly charged, an image exposure based on an image signal is performed by an image exposure device 53 as an image exposure unit. The image exposure device 53 in this figure uses a laser diode (not shown) as an exposure light source. The light on the photosensitive drum is scanned by the light whose optical path is bent by the reflection mirror 532 via the rotating polygon mirror 531, the fθ lens, and the like, and an electrostatic latent image is formed.
[0106]
Here, the reversal development process is to uniformly charge the surface of the photoreceptor by the charger 52, and to carry out the region where the image exposure has been performed, that is, the exposed portion potential (exposed portion region) of the photoreceptor by the developing step (means). This is an image forming method for visualizing the image. On the other hand, the unexposed portion potential is not developed by the developing bias potential applied to the developing sleeve 541.
[0107]
The electrostatic latent image is then developed by a developing device 54 as a developing unit. A developing device 54 containing a developer including a toner and a carrier is provided on the peripheral edge of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The inside of the developing device 54 is composed of developer stirring / conveying members 544 and 543, a conveyance amount regulating member 542, and the like. The developer is agitated and conveyed and supplied to the developing sleeve. Controlled by member 542. The transport amount of the developer varies depending on the linear velocity of the applied organic electrophotographic photosensitive member and the specific gravity of the developer, but is generally in the range of ^{20 to} 200 mg / cm ² .
[0108]
The developer is, for example, a carrier in which an insulating resin is coated around a ferrite core, a coloring agent such as carbon black, a styrene acrylic resin as a main material, a charge controlling agent, and colored particles composed of a low molecular weight polyolefin, and silica. And a toner to which titanium oxide or the like is externally added. The developer is transported to a developing area with the layer thickness regulated by a transport amount regulating member, and is developed. At this time, normally, a DC bias is applied between the photosensitive drum 50 and the developing sleeve 541, and an AC bias voltage is applied as necessary to perform the development. Further, the developer is developed in a state of contact or non-contact with the photoconductor. The potential measurement of the photoconductor is performed by providing a potential sensor 547 above the developing position as shown in FIG.
[0109]
After the image is formed, the recording paper P is fed to the transfer area by the rotation of the paper feed roller 57 at the time when the transfer timing is adjusted.
[0110]
In the transfer area, a transfer electrode (transfer means: transfer unit) 58 operates on the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and applies a charge of the opposite polarity to the toner to the fed recording paper P. Transfer the toner.
[0111]
Next, the recording paper P is discharged by a separation electrode (separator) 59, separated by the peripheral surface of the photosensitive drum 50, conveyed to the fixing device 60, and heated and pressed by the heat roller 601 and the pressure roller 602 to remove the toner. After welding, the sheet is discharged to the outside of the apparatus via a sheet discharge roller 61. After the transfer electrode 58 and the separation electrode 59 have passed through the recording paper P, the primary operation is stopped, and preparation is made for the formation of the next toner image. In FIG. 1, the transfer electrode 58 is a corotron transfer band electrode. The setting conditions of the transfer electrode vary depending on the process speed (peripheral speed) of the photoconductor and cannot be specified unconditionally. For example, the transfer current is set to +100 to +400 μA and the transfer voltage is set to +500 to +2000 V. can do.
[0112]
On the other hand, after the recording paper P is separated, the photosensitive drum 50 removes and cleans the residual toner by pressing the blade 621 of the cleaning device (cleaning means) 62, and removes electricity by the pre-charging exposure unit 51 again and charges by the charger 52. Then, the process of the next image formation is started.
[0113]
Reference numeral 70 denotes a detachable process cartridge in which a photosensitive member, a charger, a transfer device, a separator, and a cleaning device are integrated.
[0114]
The organic electrophotographic photoreceptor of the present invention is generally applicable to electrophotographic devices such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, and furthermore, displays, recording, light printing, and plate making using electrophotographic technology. Also, the present invention can be widely applied to apparatuses such as facsimile machines.
[0115]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. Note that “parts” in the text represents parts by mass.
[0116]
Preparation of Photoconductor 1 Photoconductor 1 was prepared as described below.
[0117]
<Intermediate layer>
Polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) 10.0 parts Titanium oxide “SMT500SAS” (manufactured by Teica Corporation) 30.0 parts Methanol 100.0 parts The above components are circulated and wet-dispersed (Dispermat SLC12EX; VMA GETZMANN). (Manufactured by K.K.) to prepare an intermediate layer coating solution. The intermediate layer coating solution was applied onto a cylindrical aluminum substrate having a diameter of 80 mm by dip coating to form an intermediate layer having a dry film thickness of 1.5 μm.
[0118]

The above components were mixed and dispersed by a sand grinder to prepare a charge generation layer coating solution, and the charge generation layer coating solution was applied onto the intermediate layer by dip coating to form a charge generation layer having a dry thickness of 0.3 μm. .
[0119]

The above components were mixed and dissolved to prepare a charge transport layer coating solution. The charge transport layer coating solution was applied onto the charge generation layer using a circular slide hopper type coating machine to form a charge transport layer having a dry film thickness of 20 μm.
[0120]
<Surface protective layer>
A mixture of 10 parts of a hydrolyzable silane having a polymerizable group (JS-1), 30 parts of a colloidal silica (number average primary particle diameter of 35 nm) as a solid content and 300 parts of t-butyl alcohol is heated and refluxed for 5 minutes. Then, a composition containing silica having a polymerizable group was prepared. After cooling the composition, 25 parts of a polymerizable monomer (M-1), 3 parts of a polymerization initiator (2,2-diethoxyacetophenone), and a charge transporting compound having a polymerizable group (CTMR-21) were added. This curable composition (coating solution) was applied on the charge transporting layer, dried and then irradiated with ultraviolet light at a light intensity of 80 mW / cm ² for 30 seconds using a high-pressure mercury lamp to give a 3.0 μm-thick film. A surface protective layer was formed, and photoreceptor 1 was produced.
[0121]
Preparation of Photoreceptors 2 to 7 In the preparation of Photoreceptor 1, the cured film of the present invention was prepared in the same manner as in Photoreceptor 1 except that the composition of the coating solution (curable composition) for the surface protective layer was changed as shown in Table 1. Photoconductors 2 to 7 having a surface protective layer were prepared.
[0122]
Preparation of Photoreceptor 8 Photoreceptor 8 was prepared in the same manner as in Preparation of Photoreceptor 1, except that the surface protective layer was formed as described below.
[0123]
<Surface protective layer>
A mixture of 10 parts of a hydrolyzable silane having a polymerizable group (JS-1), 30 parts of colloidal silica (number average primary particle diameter of 15 nm) as a solid content and 300 parts of t-butyl alcohol is heated to reflux for 5 minutes. Then, a composition containing silica having a polymerizable group was prepared. After cooling the composition, 3 parts of a polymerization initiator (2,2-diethoxyacetophenone) and 65 parts of a charge transporting compound having a polymerizable group (CTMR-42) are added, and the curable composition (coating liquid) is added. Was applied onto the charge transport layer, dried, and then irradiated with ultraviolet light at a light intensity of 80 mW / cm ² for 30 seconds using a high-pressure mercury lamp to form a 3.0 μm-thick surface protective layer. .
[0124]
Production of photoconductor 9 (comparative photoconductor)
In the preparation of the photoreceptor 1, except that the charge transporting compound having a polymerizable group (CTMR-21) was removed from the coating solution for the surface protective layer, and the polymerizable monomer was changed from M-1 to butylene glycol diacrylate. In the same manner as in photoconductor 1, photoconductor 9 having a surface protective layer of a cured film for comparison was prepared.
[0125]
Production of photoconductor 10 (comparative photoconductor)
Photoreceptor 1 was prepared in the same manner as photoreceptor 1 except that colloidal silica was removed from the coating solution for the surface protective layer.
[0126]
Production of photoconductor 11 (comparative photoconductor)
Photoconductor 11 was manufactured in the same manner as photoconductor 1, except that the surface protective layer was not provided and the dry thickness of the charge transport layer was 25 μm.
[0127]
[Table 1]

[0128]
Konica "Sitios 7075" digital copier manufactured by Konica Corporation (corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, blade cleaning, cleaning auxiliary brush roller adoption process as a evaluation and evaluation machine, print speed 75 sheets / min. ), The photoconductors 1 to 11 were mounted on the copying machine and evaluated. The evaluation was performed by copying an original image having a character ratio of 7%, a portrait image of a person, a solid white image, and a solid black image, each of which is equal to ４, on A4 neutral paper. The copy conditions were 100,000 copies each in a high-temperature and high-humidity environment (30 ° C., 80% RH) and a low-temperature, low-humidity environment (10 ° C., 20% RH), and the halftone, solid white image and solid black image were evaluated. did. However, before the start of copying, the surface of the photoreceptor was dusted with setting powder, and the photoreceptor and the cleaning blade were blended, and then copying was performed. The evaluation items and evaluation criteria are shown below.
[0129]
Evaluation Items and Evaluation Standard Image Density (measured using Macbeth RD-918. Measured with relative reflection density assuming that the reflection density of paper is "0". Evaluated both at initial stage and after copying 200,000 sheets)
A: 1.2 or more both at the initial stage and after copying 200,000 sheets: good O: 1.0 or more at both the initial stage and after copying 200,000 sheets: no problem in practical use X: Initial and after copying 200,000 sheets At least one of them is less than 1.0: Level fog which is problematic in practical use (determined by solid white image density. Evaluated both at initial stage and after copying 200,000 sheets) Printed using "RD-918" manufactured by Macbeth Co. The density of the copy paper (blank paper) that has not been used is measured at 20 locations based on the absolute image density, and the average value is defined as the blank paper density. Next, absolute image densities were similarly measured at 20 white background portions of the evaluation paper on which an image was formed, and a value obtained by subtracting the white paper density from the average density was evaluated as a fog density.
[0130]
：: 0.005 or less for both initial and after 200,000 copies (good)
：: 0.01 or less both at the initial stage and after 200,000 copies (a level that is practically acceptable)
X: At least one of the initial and after 200,000 copies is higher than 0.01 (obviously a practical problem)
Image blur An image in a high-temperature and high-humidity environment (30 ° C. 80% RH) and a low-temperature and low-humidity environment (10 ° C. 20% RH) using an original image having a grid image with a width of 5 cm produced by lines at intervals of 0.1 mm. Was formed, the image was magnified 20 times, and the sharpness and independence of the lines were observed.
[0131]
◎: There is no image blur, and each line image is reproduced within a range of ± 20% of the original image (good)
：: Image blur is small, and each line image is reproduced within the range of ± (21 to 40%) of the original image (no problem in practical use)
Δ: Image blur is large, and each line image is reproduced within a range of ± (41 to 75%) of the original image (not suitable for high gradation image quality).
×: Image blur is remarkable, each line image is ± 76% or more of the original image, or the line interval is broken (a problem in practical use)
Sharpness The sharpness of an image was evaluated in both low-temperature and low-humidity (10 ° C., 20% RH) and high-temperature, high-humidity (30 ° C., 80% RH) environments, and evaluated by character collapse. Three-point and five-point character images were formed and evaluated according to the following criteria.
[0132]
◎: 3 points and 5 points are clear and easily readable ○: 3 points are partially unreadable, 5 points are clear and easily readable ×: 3 points are almost unreadable and 5 points and 1 point Part or all of the film thickness was not readable. The amount of wear was determined by calculating the difference between the average film thickness of the photosensitive layer measured at the start of the actual printing evaluation and at the end of 200,000 sheet copying, and used as the film thickness wear.
[0133]
Thickness measurement method The thickness of the photosensitive layer is measured at random at 10 locations of uniform thickness, and the average value is defined as the thickness of the photosensitive layer. The film thickness is measured using an eddy current type film thickness measuring device EDDY560C (manufactured by HELMUT FISCHER GMBTE CO), and the difference between the thicknesses of the photosensitive layers before and after the actual photographing test is defined as the thickness loss.
[0134]
Other evaluation conditions The other evaluation conditions using the above-mentioned Satios 7075 were set to the following conditions.
[0135]
Charging condition Charger: Scorotron charger, initial charging potential is -750V
Exposure condition Exposure part potential is set to -50 to -150 V Exposure condition DC bias; -550 V
The developer is a colored particle with a volume average particle diameter of 5 μm containing a carrier coated with an insulating resin with ferrite as a core, a colorant such as carbon black, a charge control agent, and a low molecular weight polyolefin with a styrene acrylic resin as a main material. Using a developer using a toner externally added with silica, titanium oxide, etc. Transfer conditions Transfer pole; Corona charging system Cleaning conditions Hardness 70 °, rebound resilience 65%, thickness 2 (mm), free length 9 mm Was brought into contact with the cleaning blade in the counter direction by a weight load method so as to have a linear pressure of 18 (N / m).
[0136]
The evaluation results are shown in Table 2.
[0137]
[Table 2]

[0138]
As is clear from Table 2, the photoreceptors 1 to 8 having the surface layer of the cured film of the present invention show good electrophotographic characteristics such as image density and fog, and have small image blur and good sharpness. Also, the thickness loss is small. In particular, combinations 1 to 6 of the photoconductors 1 to 6 using the charge transporting compound having one polymerizable group achieved excellent evaluation results in all evaluation items. On the other hand, the photoreceptor 9 containing no charge transporting compound having a polymerizable group in the surface layer is inferior in image density and image blur evaluation, and as a result, sharpness is deteriorated. In the photoreceptor 10 containing no silica, the amount of thickness loss increases, and as a result, the image density decreases and the sharpness deteriorates. The photoreceptor 11 having no surface protective layer has the same tendency as the photoreceptor 10.
[0139]
【The invention's effect】
As is clear from the examples, by using the configuration of the present invention, by using the electrophotographic photoreceptor, the electrophotographic properties, image blur, sharpness are improved, and a high-quality, highly durable organic photoreceptor is obtained. Can be provided. Further, it is possible to provide a method for producing the organic photoreceptor, an image forming method, an image forming apparatus, and a process cartridge capable of achieving a good electrophotographic image using the organic photoreceptor.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an image forming apparatus as one example of an image forming method of the present invention.
[Explanation of symbols]
50 Photoconductor drum (or photoconductor)
51 Exposure unit before charging 52 Charger 53 Image exposure unit 54 Developing unit 541 Developing sleeve 543, 544 Developer stirring and conveying member 547 Potential sensor 57 Feed roller 58 Transfer electrode 59 Separation electrode (separator)
Reference Signs List 60 fixing device 61 discharge roller 62 cleaning device 70 process cartridge

Claims (9)

In an organic photoreceptor having a photosensitive layer on a conductive support, the photosensitive layer has a cured film formed from a curable composition containing a charge transporting compound having a polymerizable group and silica having a polymerizable group. An organic photoreceptor, characterized in that: The organic photoreceptor according to claim 1, wherein the silica having a polymerizable group is a silica surface-treated with a hydrolyzable silane having a polymerizable group. The organic photoconductor according to claim 2, wherein the hydrolyzable silane having a polymerizable group is a compound having a carbon-carbon double bond. The organic photoreceptor according to any one of claims 1 to 3, wherein the charge transporting compound having a polymerizable group has one polymerizable group. In an organic photoreceptor having a photosensitive layer on a conductive support, the surface layer of the organic photoreceptor was formed from a curable composition containing a charge transporting compound having a polymerizable group and silica having a polymerizable group. An organic photoreceptor, which is a cured film. In a method for producing an organic photoreceptor having a photosensitive layer on a conductive support, a charge-transporting compound having a polymerizable group and a curable composition containing silica having a polymerizable group are coated on the conductive support. A method for producing an organic photoreceptor, comprising a step of forming a cured film by heating. Organic photosensitive body having a photosensitive layer on a conductive support, wherein the photosensitive layer has a cured film formed from a curable composition containing a charge transporting compound having a polymerizable group and silica having a polymerizable group. Charging means for uniformly charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, and developing for visualizing the electrostatic latent image on the organic photoreceptor Means, transfer means for transferring a toner image visualized on the organic photoreceptor onto a transfer material, charge removing means for removing charge on the organic photoreceptor after transfer, and transfer on the organic photoreceptor after transfer A process cartridge, wherein at least one of cleaning means for removing residual toner is integrally supported, and is detachably attachable to an image forming apparatus main body. An image forming apparatus comprising the process cartridge according to claim 7. An image forming method for forming an electrophotographic image using the image forming apparatus according to claim 8.

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