JP3817192B2 - Electrophotographic equipment - Google Patents

Description

【０１０３】
感光体は、オゾンやＮＯｘガスの曝露によって、帯電性が低下したり耐摩耗性が低下したりするが、酸化防止剤が添加されることで、静電特性が安定化される。つまり、長期の繰り返し使用時における画質安定化が実現される。
【０１０４】
また、最表面層にフィラーが添加されている場合、オゾンあるいはＮＯｘのガス成分がフィラーに吸着しやすくなるため、画像ボケの影響がフィラーのない場合に比べてやや増加する。これに対し、ヒンダードフェノール構造及びヒンダードアミン構造の両構造を有する酸化防止剤をフィラーとともに含有されると、異常画像の発生確率を極めて低くできることが分かった。
つまり、フィラーと上記酸化防止剤とを組み合わせて用いることによって、異常画像の発生確率を極めて低くできるため、一層の高画質化を実現できる。
【０１０５】
また、最表面層におけるグラフト共重合体の含有量が多いと、得られる感光体（最表面層）の帯電性が低下してしまうことがある。特に、オゾンやＮＯｘガスが曝露することでこの現象は強くなる。これに対し、感光体の最表面層にこれらの酸化防止剤を添加することによってこれを防止できる。この効果が高い酸化防止剤は、１−［２−〔３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ〕エチル］−４−〔３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ〕−２，２，６，６−テトラメチルピリジンである。
【０１０６】
次に、感光体の各層について説明する。なお、前記したように、以下に説明する各層は、その全部が最表面層であってもよく（全域にグラフト共重合体が含有されていてもよく）、一部が最表面層であってもよい。また、下記に記す以外の層が設けられてもよい。
【０１０７】
〈導電性支持体３１〉
導電性支持体３１は、感光層３３などの各層を支持するための土台となる層で、体積抵抗が１０¹⁰Ω・ ｃｍ以下の導電性を示す層である。
導電性支持体３１は、例えば次のようなものを採用できる。
・アルミニウム、ニッケル、クロム、ニクロム、銅、金、銀、白金などの金属、酸化スズ、酸化インジウムなどの金属酸化物を、フィルム状又は円筒状のプラスチックや紙に蒸着法又はスパッタリング法などにより被覆させたもの。
・アルミニウム、アルミニウム合金、ニッケル、ステンレスなどの板。
・アルミニウム、アルミニウム合金、ニッケル、ステンレスなどを押し出し／引き抜き、切削／超仕上げ／研摩などの表面処理を施した管。
・エンドレスニッケルベルト、エンドレスステンレスベルトなど（特開昭５２−３６０１６号公報などに記載）。
【０１０８】
また、任意の支持体上に、導電性粉体を適当な結着樹脂（導電性支持体３１用結着樹脂）に分散して塗工したものも、導電性支持体３１として用いることができる。つまり、導電性粉体と結着樹脂を、適当な溶剤又は分散媒に溶解又は分散して塗工液を作成し、この塗工液を上記支持体上に塗布することで作成できる。
導電性粉体は、例えば、アルミニウム、ニッケル、鉄、ニクロム、銅、亜鉛、銀などの金属粉、導電性酸化スズ、ＩＴＯなどの金属酸化物粉体、カーボンブラック、アセチレンブラックなどがあげられる。
導電性粉体が分散される結着樹脂は、例えば、ポリスチレン、スチレン−アクリロニトリル共重合体、スチレン−ブタジエン共重合体、スチレン−無水マレイン酸共重合体、ポリエステル、ポリ塩化ビニル、塩化ビニル−酢酸ビニル共重合体、ポリ酢酸ビニル、ポリ塩化ビニリデン、ポリアリレート樹脂、フェノキシ樹脂、ポリカーボネート、酢酸セルロース樹脂、エチルセルロース樹脂、ポリビニルブチラール、ポリビニルホルマール、ポリビニルトルエン、ポリ−Ｎ−ビニルカルバゾール、アクリル樹脂、シリコーン樹脂、エポキシ樹脂、メラミン樹脂、ウレタン樹脂、フェノール樹脂、アルキッド樹脂などの熱可塑性樹脂、熱硬化性樹脂または光硬化性樹脂が挙げられる。
導電性粉体及び結着樹脂を溶解又は分散させる溶剤又は分散媒は、例えば、テトラヒドロフラン、ジクロロメタン、メチルエチルケトン、トルエンなどが上げられる。
【０１０９】
適当な円筒基体上に、上記導電性粉体が含有された、ポリ塩化ビニル、ポリプロピレン、ポリエステル、ポリスチレン、ポリ塩化ビニリデン、ポリエチレン、塩化ゴム、テフロン（登録商標）などの熱収縮チューブが被覆されたもの（導電性層が設けられたもの）も導電性支持体３１として良好に用いることができる。
【０１１０】
〈積層型の感光層３３〉
感光層３３は、図１に示すように単層型のものと図２に示すような積層型のものがある。まず、積層型の感光層３３について説明する。積層型の感光層３３は、電荷発生層３５と電荷輸送層３７とを有する。
【０１１１】
〈電荷発生層３５〉
電荷発生層３５は、電荷発生物質が主成分で、必要に応じて結着樹脂（電荷発生層３５形成用結着樹脂）も含有される。また、任意の添加剤も含有される。
【０１１２】
電荷発生物質は、無機系材料を用いてもよく、有機系材料を用いてもよい。
無機系材料は、例えば、結晶セレン、アモルファス・セレン、セレン−テルル、セレン−テルル−ハロゲン、セレン−ヒ素化合物、硫化カドミウム、硫化カドミウム−セレン、アモルファス・シリコン等が挙げられる。アモルファス・シリコンは、ダングリングボンドを水素原子やハロゲン原子でタ−ミネ−トしたものや、ホウ素原子、リン原子等をド−プしたものが良好に用いられる。
【０１１３】
有機系材料は、公知の材料を採用できる。例えば、ジスアゾ顔料、非対称ジスアゾ顔料、トリスアゾ顔料、カルバゾ−ル骨格を有するアゾ顔料（特開昭５３−９５０３３号公報に記載）、ジスチリルベンゼン骨格を有するアゾ顔料（特開昭５３−１３３４４５号公報）、トリフェニルアミン骨格を有するアゾ顔料（特開昭５３−１３２３４７号公報に記載）、ジフェニルアミン骨格を有するアゾ顔料、ジベンゾチオフェン骨格を有するアゾ顔料（特開昭５４−２１７２８号公報に記載）、フルオレノン骨格を有するアゾ顔料（特開昭５４−２２８３４号公報に記載）、オキサジアゾ−ル骨格を有するアゾ顔料（特開昭５４−１２７４２号公報に記載）、ビススチルベン骨格を有するアゾ顔料（特開昭５４−１７７３３号公報に記載）、ジスチリルオキサジアゾ−ル骨格を有するアゾ顔料（特開昭５４−２１２９号公報に記載）、ジスチリルカルバゾ−ル骨格を有するアゾ顔料（特開昭５４−１４９６７号公報に記載）等のアゾ系顔料、アズレニウム塩顔料、スクエアリック酸メチン顔料、ペリレン系顔料、アントラキノン系顔料、多環キノン系顔料、キノンイミン系顔料、ジフェニルメタン系顔料、トリフェニルメタン系顔料、ベンゾキノン系顔料、ナフトキノン系顔料、シアニン系顔料、アゾメチン系顔料、インジゴイド系顔料、ビスベンズイミダゾ−ル系顔料、下記一般式（Ｎ）で表される金属フタロシアニン、無金属フタロシアニン等のフタロシアニン系顔料等が挙げられる。
これらの電荷発生物質は、単独で用いてもよく、２種以上を混合して用いてもよい。
【０１１４】
【化２】

【０１１５】
上記一般式（Ｎ）中、Ｍ（中心金属）は、金属及び無金属（水素）の元素を表す。Ｍ（中心金属）は、Ｈ、Ｌｉ、Ｂｅ、Ｎａ、Ｍｇ、Ａｌ、Ｓｉ、Ｋ、Ｃａ、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｇａ、Ｇｅ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ｔｃ、Ｒｕ、Ｒｈ、Ｐｄ、Ａｇ、Ｃｄ、Ｉｎ、Ｓｎ、Ｓｂ、Ｂａ、Ｈｆ、Ｔａ、Ｗ、Ｒｅ、Ｏｓ、Ｉｒ、Ｐｔ、Ａｕ、Ｈｇ、ＴＩ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、Ｔｈ、Ｐａ、Ｕ、Ｎｐ、Ａｍ等の単体（元素）や、これらの元素の酸化物、塩化物、フッ化物、水酸化物、臭化物などが挙げられるが、これらに限定されるものではない。
なお、上記一般式（Ｎ）で表される化合物は、２量体、３量体など多量体構造をとっていてもよく、さらに高次の高分子構造をとっていてもよい。また、上記一般式（Ｎ）で表される基本骨格に様々な置換基があってもよい。
【０１１６】
なお、中心金属にＴｉＯを有するオキソチタニウムフタロシアニン、無金属フタロシアニン、クロロガリウムフタロシアニン等は、良好な感光体特性（電荷発生性等）が得られるため好ましく用いられる。
また、フタロシアニンは、様々な結晶系を持つことが知られており、例えばオキソチタニウムフタロシアニンの場合、α、β、γ、ｍ、Ｙ型等、銅フタロシアニンの場合、α、β、γ等の結晶多系を有している。同じ中心金属を持つフタロシアニンも、結晶系が変わることにより種々の特性も変化する。これらの種々の結晶系を有するフタロシアニン系顔料を用いた感光体の特性もそれに伴って変化することが報告されている（電子写真学会誌 第２９巻 第４号( １９９０) ）。このように、フタロシアニンの結晶系の選択は、感光体特性上非常に重要である。中でも、Ｙ型オキソチタニウムフタロシアニンを含有する感光体は高感度化に対して有効であることが知られている。
【０１１７】
電荷発生層３５形成用結着樹脂は、例えば、ポリアミド、ポリウレタン、エポキシ樹脂、ポリケトン、ポリカ−ボネ−ト、シリコ−ン樹脂、アクリル樹脂、ポリビニルブチラ−ル、ポリビニルホルマ−ル、ポリビニルケトン、ポリスチレン、ポリ−Ｎ−ビニルカルバゾ−ル、ポリアクリルアミドなどが挙げられる。これらの結着樹脂は、単独で用いてもよく、２種以上の混合物として用いてもよい。
【０１１８】
また、電荷発生層３５形成用結着樹脂として、後述の高分子電荷輸送物質（例えば、特開昭６４−１７２８号公報、特開昭６４−１３０６１号公報、特開昭６４−１９０４９号公報、特開平４−１１６２７号公報、特開平４−２２５０１４号公報、特開平４−２３０７６７号公報、特開平４−３２０４２０号公報、特開平５−２３２７２７号公報、特開平６−２３４８３８号公報、特開平６−２３４８３９号公報、特開平６−２９５０７７号公報、特開平７−５６３７４号公報、特開平７−３２５４０９号公報、特開平９−８０７７２号公報、特開平９−８０７８３号公報、特開平９−８０７８４号公報、特開平９−１２７７１３号公報、特開平９−２１１８７７号公報、特開平９−２２２７４０号公報、特開平９−２６５１９７号公報、特開平９−２６５２０１号公報、特開平９−２９７４１９号公報、特開平９−３０４９５６号公報記載の物質）を用いることもできる。
【０１１９】
電荷発生層３５形成用結着樹脂は、電荷発生物質１００重量部に対し、０重量部を超えて５００重量部以下の量、好ましくは０重量部を超えて２００重量部以下の量含有される。
また、必要に応じて、ジメチルシリコ−ンオイル、メチルフェニルシリコ−ンオイル等のレベリング剤や増感剤、分散剤等の各種添加剤を添加できる。
【０１２０】
電荷発生層３５の形成方法は、真空薄膜作製法を採用してもよく、溶液分散系からのキャスティング法を採用することもできる。
真空薄膜作成法は、真空蒸着法、グロ−放電分解法、イオンプレ−ティング法、スパッタリング法、反応性スパッタリング法、ＣＶＤ法等があり、無機系電荷発生物質、有機系電荷発生物質を採用する場合に良好に用いられる。
キャスティング法では例えば次のように電荷輸送層３７を形成する。まず、無機系電荷発生物質又は有機系電荷発生物質を、必要に応じて結着樹脂と共に、テトラヒドロフラン、ジオキサン、ジオキソラン、トルエン、ジクロロメタン、モノクロロベンゼン、ジクロロエタン、シクロヘキサノン、シクロペンタノン、アニソール、キシレン、メチルエチルケトン、アセトン、酢酸エチル、酢酸ブチル等の溶媒又は分散媒に、ボ−ルミル、アトライタ−、サンドミル、ビーズミル等により溶解又は分散して塗工液を得る。そして、この塗工液を適度に希釈して、被塗布層上に塗布することにより形成できる。塗布液の塗布は、浸漬塗工法、スプレ−コ−ト法、ビ−ドコ−ト法、リングコート法など従来公知の方法を採用できる。
電荷発生層３５の膜厚は、０．０１〜５μｍ、好ましくは０．０５〜２μｍである。
【０１２１】
〈電荷輸送層３７〉
電荷輸送層３７は、電荷輸送物質を主成分とし、適宜、結着樹脂（電荷輸送層３７形成用結着樹脂）や添加剤を添加できる。
電荷輸送物質は、正孔輸送物質や電子輸送物質などを採用できる。
【０１２２】
電子輸送物質は、例えば、クロルアニル、ブロムアニル、テトラシアノエチレン、テトラシアノキノジメタン、２，４，７−トリニトロ−９−フルオレノン、２，４，５，７−テトラニトロ−９−フルオレノン、２，４，５，７−テトラニトロキサントン、２，４，８−トリニトロチオキサントン、２，６，８−トリニトロ−４Ｈ−インデノ〔１，２−ｂ〕チオフェン−４−オン、１，３，７−トリニトロジベンゾチオフェン−５，５−ジオキサイド、ジフェノキノン誘導体などの電子受容性物質が挙げられる。これらの物質は、単独で用いてもよく、２種以上の混合物として用いてもよい。
【０１２３】
正孔輸送物質は、例えば、オキサゾール誘導体、オキサジアゾール誘導体、イミダゾール誘導体、モノアリールアミン誘導体、ジアリールアミン誘導体、トリアリールアミン誘導体、スチルベン誘導体、α−フェニルスチルベン誘導体、ベンジジン誘導体、ジアリールメタン誘導体、トリアリールメタン誘導体、９−スチリルアントラセン誘導体、ピラゾリン誘導体、ジビニルベンゼン誘導体、ヒドラゾン誘導体、インデン誘導体、ブタジェン誘導体、ピレン誘導体等、ビススチルベン誘導体、エナミン誘導体等の電子供与性物質が良好に用いられる。また、これら以外の公知の材料も採用できる。これらの物質は、単独で用いてもよく、２種以上の混合物として用いてもよい。
【０１２４】
電荷輸送層３７形成用結着樹脂は、例えば、ポリスチレン、スチレン−アクリロニトリル共重合体、スチレン−ブタジエン共重合体、スチレン−無水マレイン酸共重合体、ポリエステル、ポリ塩化ビニル、塩化ビニル−酢酸ビニル共重合体、ポリ酢酸ビニル、ポリ塩化ビニリデン、ポリアリレート樹脂、フェノキシ樹脂、ポリカーボネート、酢酸セルロース樹脂、エチルセルロース樹脂等が挙げられる。これらの樹脂は、単独で用いてもよく、２種以上混合して用いてもよい。
【０１２５】
また、電荷輸送層３７は、電荷輸送層３７形成用結着樹脂としての機能と電荷輸送物質としての機能を持った高分子電荷輸送物質も良好に使用される。高分子電荷輸送物質が含有された電荷輸送層３７は、耐摩耗性に優れ、高画質な画像が得られる。なお、電荷輸送層３７形成用結着樹脂や上記低分子電荷輸送物質を混合して用いてもよい。
高分子電荷輸送物質は、公知の材料が使用できるが、特に、トリアリールアミン構造を主鎖および／または側鎖に含むポリカーボネートが良好に用いられる。特に、下記構造式（Ｉ）〜（Ｘ）式で表される高分子電荷輸送物質が良好に用いられる。
【０１２６】
【化３】

【０１２７】
上記一般式（Ｉ）中、Ｒ₁ 、Ｒ₂ 、Ｒ₃ は、それぞれ同一でも異なっていてもよい置換若しくは無置換のアルキル基又はハロゲン原子を表す；Ｒ₄ は、水素原子又は置換若しくは無置換のアルキル基を表す；Ｒ₅ 、Ｒ₆ は、それぞれ同一でも異なっていてもよい、置換又は無置換のアリール基を表す；ｏ、ｐ、ｑは、０〜４の整数を表す；ｋ、ｊは組成（モル分率）を表し、０．１≦ｋ≦１、０≦ｊ≦０．９のである；ｎは、繰り返し単位数を表し、５〜５０００の整数である；Ｘは、脂肪族の２価基、環状脂肪族の２価基又は上記一般式（１）で示される２価基を表す。
【０１２８】
上記一般式（１）中、Ｒ₁₀₁ 、Ｒ₁₀₂ は、それぞれ同一でも異なっていてもよい置換若しくは無置換のアルキル基、アリール基又はハロゲン原子を表す；ｌ、ｍは０〜４の整数を表す；Ｙは、単結合、炭素原子数１〜１２の直鎖状、分岐状若しくは環状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ₂ −、−ＣＯ−、−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（Ｚは脂肪族の２価基を表す）又は上記一般式（２）で表される２価基を表す。
【０１２９】
上記一般式（２）中、ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ₁₀₃ 、Ｒ₁₀₄ は置換若しくは無置換のアルキル基又はアリール基を表す。
【０１３０】
【化４】

【０１３１】
上記一般式（II）中、Ｒ₇ 、Ｒ₈ は、同一でも異なっていてもよい置換又は無置換のアリール基、Ａｒ₁ 、Ａｒ₂ 、Ａｒ₃ は同一でも異なっていてもよいアリレン基を表す。Ｘ、ｋ、ｊ、ｎは、上記一般式（Ｉ）と同じである。
【０１３２】
【化５】

【０１３３】
上記一般式（III ）中、Ｒ₉ 、Ｒ₁₀は、同一でも異なっていてもよい置換又は無置換のアリール基、Ａｒ₄ 、Ａｒ₅ 、Ａｒ₆ は同一でも異なっていてもよいアリレン基を表す。Ｘ、ｋ、ｊ、ｎは、上記一般式（Ｉ）と同じである。
【０１３４】
【化６】

【０１３５】
上記一般式（IV）中、Ｒ₁₁、Ｒ₁₂は、同一でも異なっていてもよい置換又は無置換のアリール基、Ａｒ₇ 、Ａｒ₈ 、Ａｒ₉ は、同一でも異なっていてもよいアリレン基を表し、ｐは１〜５の整数を表す。Ｘ、ｋ、ｊ、ｎは、上記一般式（Ｉ）と同じである。
【０１３６】
【化７】

【０１３７】
上記一般式（Ｖ）中、Ｒ₁₃、Ｒ₁₄は、同一でも異なっていてもよい置換又は無置換のアリール基、Ａｒ₁₀、Ａｒ₁₁、Ａｒ₁₂は、同一でも異なっていてもよいアリレン基、Ｘ₁ 、Ｘ₂ は、同一でも異なっていてもよい置換若しくは無置換のエチレン基又は置換若しくは無置換のビニレン基を表す。Ｘ、ｋ、ｊ、ｎは、一般式（Ｉ）と同じである。
【０１３８】
【化８】

【０１３９】
上記一般式（VI）中、Ｒ₁₅、Ｒ₁₆、Ｒ₁₇、Ｒ₁₈は、同一でも異なっていてもよい置換又は無置換のアリール基、Ａｒ₁₃、Ａｒ₁₄、Ａｒ₁₅、Ａｒ₁₆は同一でも異なっていてもよいアリレン基、Ｙ₁ 、Ｙ₂ 、Ｙ₃ は同一でも異なっていてもよい単結合、置換若しくは無置換のアルキレン基、置換若しくは無置換のシクロアルキレン基、置換若しくは無置換のアルキレンエーテル基、酸素原子、硫黄原子又はビニレン基を表す。Ｘ、ｋ、ｊ、ｎは、上記一般式（Ｉ）と同じである。
【０１４０】
【化９】

【０１４１】
上記一般式（VII ）中、Ｒ₁₉、Ｒ₂₀は、同一でも異なっていてもよい水素原子又は置換若しくは無置換のアリール基を表し、互いに環を形成していてもよい。Ａｒ₁₇、Ａｒ₁₈、Ａｒ₁₉は同一でも異なっていてもよいアリレン基を表す。Ｘ、ｋ、ｊ、ｎは、一般式（Ｉ）と同じである。
【０１４２】
【化１０】

【０１４３】
上記一般式（VIII）中、Ｒ₂₁は、置換又は無置換のアリール基、Ａｒ₂₀、Ａｒ₂₁、Ａｒ₂₂、Ａｒ₂₃は同一でも異なっていてもよいアリレン基を表す。Ｘ、ｋ、ｊ、ｎは、上記一般式（Ｉ）と同じである。
【０１４４】
【化１１】

【０１４５】
上記一般式（IX）中、Ｒ₂₂、Ｒ₂₃、Ｒ₂₄、Ｒ₂₅は同一でも異なっていてもよい置換又は無置換のアリール基、Ａｒ₂₄、Ａｒ₂₅、Ａｒ₂₆、Ａｒ₂₇、Ａｒ₂₈は同一でも異なっていてもよいアリレン基を表す。Ｘ、ｋ、ｊ、ｎは、上記一般式（Ｉ）と同じである。
【０１４６】
【化１２】

【０１４７】
上記一般式（Ｘ）中、Ｒ₂₆、Ｒ₂₇は同一でも異なっていてもよい置換又は無置換のアリール基、Ａｒ₂₉、Ａｒ₃₀、Ａｒ₃₁は同一でも異なっていてもよいアリレン基を表す。Ｘ、ｋ、ｊ、ｎは、上記一般式（Ｉ）と同じである。
【０１４８】
以下、トリアリールアミン構造を主鎖及び／又は側鎖に含むポリカーボネートの好ましい具体例（形態）の幾つかを以下に示す。以下に示す化合物の一又は複数を用いれば、極めて優れた感光特性（高画質性等）が得られる。ただし、これらの化合物に限定されるものではない。
【０１４９】
【化１３】

【０１５０】
【化１４】

【０１５１】
【化１５】

【０１５２】
【化１６】

【０１５３】
【化１７】

【０１５４】
【化１８】

【０１５５】
【化１９】

【０１５６】
【化２０】

【０１５７】
【化２１】

【０１５８】
【化２２】

【０１５９】
高分子電荷輸送物質は、単重合体、ランダム共重合体、交互共重合体、ブロック共重合体の形態で重合される。また、結着樹脂としての機能を実現するために被膜形成能が必要である。被膜形成能を有するには、分子量が、ＧＰＣによる測定において、ポリスチレン換算分子量Ｍｗで１万〜５０万、好ましくは５万〜４０万であればよい。
このような高分子電荷輸送物質は、例えば、特開平８−２６９１８３号公報、特開平９−７１６４２号公報、特開平９−１０４７４６号公報、特開平９−２７２７３５号公報、特開平１１−２９６３４号公報、特開平９−２３５３６７号公報、特開平９−８７３７６号公報、特開平９−１１０９７６号公報、特開平９−２６８２２６号公報、特開平９−２２１５４４号公報、特開平９−２２７６６９号公報、特開平９−１５７３７８号公報、特開平９−３０２０８４号公報、特開平９−３０２０８５号公報、特開２０００−２６５９０号公報などに開示された物質を好適に採用できる。
【０１６０】
電荷輸送層３７は、例えば、少なくとも電荷輸送物質及び結着樹脂を適当な溶剤又は分散媒に溶解又は分散された塗工液を、電荷発生層３５等の被塗工層上に塗布し、乾燥させて形成できる。
【０１６１】
電荷輸送物質は、電荷輸送層３７形成用結着樹脂１００重量部に対し、２０〜３００重量部、好ましくは４０〜１５０重量部含有させる。ただし、高分子電荷輸送物質を用いる場合は、電荷輸送物質を単独で用いてもよく、結着樹脂等と併用して用いてもよい。
【０１６２】
電荷輸送層３７の形成に用いることができる溶剤（溶媒）、分散媒は、電荷発生層３５の形成に用いることができるものが使用できるが、電荷輸送物質及び結着樹脂を良好に溶解又は分散するものを適宜選択して使用する。また、複数の溶剤又は分散媒を混合して使用してもよい。
【０１６３】
電荷輸送層３７は、必要に応じて、レベリング剤や可塑剤が添加されてもよい。
レベリング剤は、例えば、ジメチルシリコ−ンオイル、メチルフェニルシリコ−ンオイル等のシリコーンオイル類や側鎖にパ−フルオロアルキル基を有するポリマ−あるいはオリゴマ−が使用できる。レベリング剤は、結着樹脂１００重量部に対して０重量部を超え１重量部以下の範囲で添加することが好ましい。
可塑剤は、ジブチルフタレ−ト、ジオクチルフタレ−ト等の公知のものを使用でき、結着樹脂１００重量部に対して０重量部を超え３０重量部以下の範囲で添加することが好ましい。
【０１６４】
塗布方法は、浸漬塗工法、スプレ−コ−ト法、ビ−ドコ−ト法、リングコート法など公知の塗布方法を採用できる。
電荷輸送層３７の膜厚は、５〜５０μｍ程度が適当である。また、良好な解像度が得られ、地肌汚れが少ないといった良好な画像特性が得られ、帯電電位、感度等の電気特性が良好な、１０〜３０μｍが好ましい。
【０１６５】
〈単層型の感光層３３〉
単層型の感光層３３は、例えば、前記した電荷発生物質、電荷輸送物質、結着樹脂（感光層３３形成用結着樹脂）等を、適当な溶剤又は分散媒に溶解又は分散された塗工液を導電性支持体等の上に塗工、乾燥することで形成できる。
電荷発生物質及び電荷輸送物質は、積層型の感光層３３で挙げた材料を使用できる。感光層３３形成用結着樹脂は、電荷輸送層３７形成用結着樹脂を使用でき、さらに、電荷発生層３５形成用結着樹脂を適宜混合して使用してもよい。また、結着樹脂として、上記高分子電荷輸送物質を採用してもよい。
感光層３３形成用結着樹脂１００重量部に対する電荷発生物質の量は、好ましくは５〜４０重量部、さらに好ましくは１０〜３０重量部である。電荷輸送物質は、結着樹脂に対し、０重量部を超え１９０重量部以下の範囲で使用することが好ましく、さらに好ましくは５０〜１５０重量部の範囲で使用する。
【０１６６】
感光層３３は、次のように作成できる。（１）電荷発生物質、結着樹脂、電荷輸送物質を、テトラヒドロフラン、ジオキサン、ジクロロエタン、シクロヘキサノン、トルエン、メチルエチルケトン、アセトン等の溶剤又は分散媒に溶解又は分散して塗工液を作成する。（２）この塗工液を、浸漬塗工法、スプレーコート法、ビードコート法、リングコート法などを用いて導電性支持体３１などの被塗工層上に塗工することで形成できる。
また、必要により、可塑剤、レベリング剤、酸化防止剤、滑剤等の各種添加剤を添加できる。
感光層３３の膜厚は５〜２５μｍ程度が適当である。
【０１６７】
〈保護層３９〉
保護層３９は、感光層３３や電荷輸送層３７などを保護するための層で、少なくとも結着樹脂（保護層３９形成用結着樹脂）が含有される。また、好ましくはフィラー材料が含有される。
保護層３９形成用結着樹脂は、電荷輸送層３７形成用結着樹脂を用いることができる。フィラー材料は、前記したものを一つ又は複数採用できる。
【０１６８】
保護層３９は、さらに電荷輸送物質を含有されてもよい。電荷輸送物質が含有された保護層３９は、残留電位を低くでき、感度劣化を抑制できるなどの利点を有する。
また、電荷輸送物質として前記した高分子電荷輸送物質を好ましく採用する。高分子電荷輸送物質が保護層３９に含有された感光体は、異常画像の発生確率が極めて低くできる。高分子電荷輸送物質は、オゾンやＮＯｘによる変質や分解が起こりにくく、また、電荷輸送物質と結着樹脂との混合系に比べて耐キズ性にも優れているからである。つまり、異常画像の発生確率を高める有機炭素系残査が生成せず又は生成しにくく、帯電生成物の除去を容易にするために、感光体表面に細かなキズができにくいため、高画質性が得られる。
保護層に用いられる電荷輸送物質及び高分子電荷輸送物質は、電荷輸送層３７で使用できる物質と同一又は類似の物質から任意に選択された一又は複数を使用できる。
【０１６９】
保護層３９は、保護層３９形成用結着樹脂を、電荷輸送層３７と同様の方法で被塗工層上に塗工すれば保護層３９を形成できる。例えば、浸漬塗工法、スプレーコート、ビートコート、ノズルコート、スピナーコート、リングコート等、公知の塗工方法を用いることができる。中でも、膜厚制御を行いやすく、グラフト共重合体やフィラーの分散性を良好に維持でき、得られた感光体（保護層３９）の塗膜品質を良好にできるスプレー塗工法を好ましく採用する。
また、一度の塗工により保護層３９を形成してもよいが、２回以上重ねて塗工して保護層３９を形成すれば、保護層３９中にフィラー材料をほぼ均一に分散できる。フィラー材料が均一に分散されると、残留電位を低く保て、解像度を高くでき、耐摩耗性を高くできる。また、塗膜品質のを高くでき、塗膜欠陥の発生を抑制できる。
保護層３９の膜厚は、０．５μｍ〜１０μｍが好ましく、２μｍ〜６μｍがより好ましい。
【０１７０】
〈下引き層〉
下引き層は、導電性支持体３１と感光層３３との間に設けることができる。
下引き層は、一般に、樹脂を主成分とするが、感光層３３が塗布されるため、有機溶剤、特に感光層３３形成用の溶剤に対して耐溶剤性の高い樹脂であることが望ましい。このような樹脂は、例えば、ポリビニルアルコール、カゼイン、ポリアクリル酸ナトリウム等の水溶性樹脂、共重合ナイロン、メトキシメチル化ナイロン等のアルコール可溶性樹脂、ポリウレタン、メラミン樹脂、フェノール樹脂、アルキッド−メラミン樹脂、エポキシ樹脂等、三次元網目構造を形成する硬化型樹脂等が挙げられる。
また、下引き層は、モアレ防止、残留電位の低減等のために酸化チタン、シリカ、アルミナ、酸化ジルコニウム、酸化スズ、酸化インジウム等の金属酸化物の微粉末顔料が添加されてもよい。
また、下引き層に、シランカップリング剤、チタンカップリング剤、クロムカップリング剤等を含有させてもよい。
【０１７１】
下引き層は、感光層３３と同様に形成できる。また、塗工用の溶媒（分散媒）も同様のものを採用すればよい。
また、Ａｌ₂ Ｏ₃ を陽極酸化法にて被塗工層上に設けられた層や、ポリパラキシリレン（パリレン）等の有機物やＳｉＯ₂ 、ＳｎＯ₂ 、ＴｉＯ₂ 、ＩＴＯ、ＣｅＯ₂ 等の無機物を真空薄膜作成法にて被塗工層上に設けられた層を下引き層としてもよい。
これら以外にも公知の層形成法を採用できる。
下引き層の膜厚は０μｍを超え５μｍ以下の範囲とするとよい。
【０１７２】
〈中間層〉
下引き層と感光層３３との間や感光層３３と保護層３９との間などに中間層を設けてもよい。
中間層は、一般に、バインダー樹脂（結着樹脂）を主成分とする。採用できる樹脂は、例えば、ポリアミド、アルコール可溶性ナイロン、水溶性ポリビニルブチラール、ポリビニルブチラール、ポリビニルアルコールなどが挙げられる。
中間層の形成法は、前記したような公知の塗工法を用いることができる。
中間層の厚さは０．０５〜２μｍが適当である。
【０１７３】
〈各層に共通の事項〉
また、耐環境性の改善のため、特に、感度低下や残留電位の上昇を防止するため、感光体における１層又は複数の層に、酸化防止剤、可塑剤、滑剤、紫外線吸収剤、低分子電荷輸送物質、レベリング剤などを適宜添加することが好ましい。
【０１７４】
〈酸化防止剤〉
酸化防止剤は、例えば以下のものが挙げられるが、これらに限定されるものではない。
（ａ）フェノール系化合物
２，６−ジ−ｔ−ブチル−ｐ−クレゾール、ブチル化ヒドロキシアニソール、２，６−ジ−ｔ−ブチル−４−エチルフェノール、ｎ−オクタデシル−３−（４’−ヒドロキシ−３’，５’−ジ−ｔ−ブチルフェノール）、２，２’−メチレン−ビス−（４−メチル−６−ｔ−ブチルフェノ−ル）、２，２' −メチレン−ビス−（４−エチル−６−ｔ−ブチルフェノール）、４，４' −チオビス−（３−メチル−６−ｔ−ブチルフェノール）、４，４' −ブチリデンビス−（３−メチル−６−ｔ−ブチルフェノール）、１，１，３−トリス−（２−メチル−４−ヒドロキシ−５−ｔ−ブチルフェニル）ブタン、１，３，５−トリメチル−２，４，６−トリス（３，５−ジ−ｔ−ブチル−４−ヒドロキシベンジル）ベンゼン、テトラキス−［メチレン−３−（３' ，５' −ジ−ｔ−ブチル−４' −ヒドロキシフェニル）プロピオネート］メタン、ビス［３，３' −ビス（４' −ヒドロキシ−３' −ｔ−ブチルフェニル）ブチリックアッシド］クリコールエステル、トコフェロール類など。
【０１７５】
（ｂ）パラフェニレンジアミン類
Ｎ−フェニル−Ｎ' −イソプロピル−ｐ−フェニレンジアミン、Ｎ，Ｎ' −ジ−ｓｅｃ−ブチル−ｐ−フェニレンジアミン、Ｎ−フェニル−Ｎ−ｓｅｃ−ブチル−ｐ−フェニレンジアミン、Ｎ，Ｎ' −ジ−イソプロピル−ｐ−フェニレンジアミン、Ｎ，Ｎ' −ジメチル−Ｎ，Ｎ' −ジ−ｔ−ブチル−ｐ−フェニレンジアミンなど。
【０１７６】
（ｃ）ハイドロキノン類
２，５−ジ−ｔ−オクチルハイドロキノン、２，６−ジドデシルハイドロキノン、２−ドデシルハイドロキノン、２−ドデシル−５−クロロハイドロキノン、２−ｔ−オクチル−５−メチルハイドロキノン、２−（２−オクタデセニル）−５−メチルハイドロキノンなど。
【０１７７】
（ｄ）有機硫黄化合物類
ジラウリル−３，３' −チオジプロピオネート、ジステアリル−３，３' −チオジプロピオネート、ジテトラデシル−３，３' −チオジプロピオネートなど。
【０１７８】
（ｅ）有機燐化合物類
トリフェニルホスフィン、トリ（ノニルフェニル）ホスフィン、トリ（ジノニルフェニル）ホスフィン、トリクレジルホスフィン、トリ（２，４−ジブチルフェノキシ）ホスフィンなど。
【０１７９】
〈可塑剤〉
可塑剤は、例えば以下のものが挙げられるが、これらに限定されるものではない。
（ａ）リン酸エステル系可塑剤
リン酸トリフェニル、リン酸トリクレジル、リン酸トリオクチル、リン酸オクチルジフェニル、リン酸トリクロルエチル、リン酸クレジルジフェニル、リン酸トリブチル、リン酸トリ−２−エチルヘキシル、リン酸トリフェニルなど。
【０１８０】
（ｂ）フタル酸エステル系可塑剤
フタル酸ジメチル、フタル酸ジエチル、フタル酸ジイソブチル、フタル酸ジブチル、フタル酸ジヘプチル、フタル酸ジ−２−エチルヘキシル、フタル酸ジイソオクチル、フタル酸ジ−ｎ−オクチル、フタル酸ジノニル、フタル酸ジイソノニル、フタル酸ジイソデシル、フタル酸ジウンデシル、フタル酸ジトリデシル、フタル酸ジシクロヘキシル、フタル酸ブチルベンジル、フタル酸ブチルラウリル、フタル酸メチルオレイル、フタル酸オクチルデシル、フマル酸ジブチル、フマル酸ジオクチルなど。
【０１８１】
（ｃ）芳香族カルボン酸エステル系可塑剤
トリメリット酸トリオクチル、トリメリット酸トリ−ｎ−オクチル、オキシ安息香酸オクチルなど。
【０１８２】
（ｄ）脂肪族二塩基酸エステル系可塑剤
アジピン酸ジブチル、アジピン酸ジ−ｎ−ヘキシル、アジピン酸ジ−２−エチルヘキシル、アジピン酸ジ−ｎ−オクチル、アジピン酸−ｎ−オクチル−ｎ−デシル、アジピン酸ジイソデシル、アジピン酸ジカプリル、アゼライン酸ジ−２−エチルヘキシル、セバシン酸ジメチル、セバシン酸ジエチル、セバシン酸ジブチル、セバシン酸ジ−ｎ−オクチル、セバシン酸ジ−２−エチルヘキシル、セバシン酸ジ−２−エトキシエチル、コハク酸ジオクチル、コハク酸ジイソデシル、テトラヒドロフタル酸ジオクチル、テトラヒドロフタル酸ジ−ｎ−オクチルなど。
【０１８３】
（ｅ）脂肪酸エステル誘導体
オレイン酸ブチル、グリセリンモノオレイン酸エステル、アセチルリシノール酸メチル、ペンタエリスリトールエステル、ジペンタエリスリトールヘキサエステル、トリアセチン、トリブチリンなど。
【０１８４】
（ｆ）オキシ酸エステル系可塑剤
アセチルリシノール酸メチル、アセチルリシノール酸ブチル、ブチルフタリルブチルグリコレート、アセチルクエン酸トリブチルなど。
【０１８５】
（ｇ）エポキシ可塑剤
エポキシ化大豆油、エポキシ化アマニ油、エポキシステアリン酸ブチル、エポキシステアリン酸デシル、エポキシステアリン酸オクチル、エポキシステアリン酸ベンジル、エポキシヘキサヒドロフタル酸ジオクチル、エポキシヘキサヒドロフタル酸ジデシルなど。
【０１８６】
（ｈ）二価アルコールエステル系可塑剤
ジエチレングリコールジベンゾエート、トリエチレングリコールジ−２−エチルブチラートなど。
【０１８７】
（ｉ）含塩素可塑剤
塩素化パラフィン、塩素化ジフェニル、塩素化脂肪酸メチル、メトキシ塩素化脂肪酸メチルなど。
【０１８８】
（ｊ）ポリエステル系可塑剤
ポリプロピレンアジペート、ポリプロピレンセバケート、ポリエステル、アセチル化ポリエステルなど。
【０１８９】
（ｋ）スルホン酸誘導体
ｐ−トルエンスルホンアミド、ｏ−トルエンスルホンアミド、ｐ−トルエンスルホンエチルアミド、ｏ−トルエンスルホンエチルアミド、トルエンスルホン−Ｎ−エチルアミド、ｐ−トルエンスルホン−Ｎ−シクロヘキシルアミドなど。
【０１９０】
（ｌ）クエン酸誘導体
クエン酸トリエチル、アセチルクエン酸トリエチル、クエン酸トリブチル、アセチルクエン酸トリブチル、アセチルクエン酸トリ−２−エチルヘキシル、アセチルクエン酸−ｎ−オクチルデシルなど。
【０１９１】
（ｍ）その他
ターフェニル、部分水添ターフェニル、ショウノウ、２−ニトロジフェニル、ジノニルナフタリン、アビエチン酸メチルなど。
【０１９２】
〈滑剤〉
滑剤は、例えば以下のものが挙げられるが、これらに限定されるものではない。
（ａ）炭化水素系化合物
流動パラフィン、パラフィンワックス、マイクロワックス、低重合ポリエチレンなど。
【０１９３】
（ｂ）脂肪酸系化合物
ラウリン酸、ミリスチン酸、パルチミン酸、ステアリン酸、アラキジン酸、ベヘン酸など。
【０１９４】
（ｃ）脂肪酸アミド系化合物
ステアリルアミド、パルミチルアミド、オレインアミド、メチレンビスステアロアミド、エチレンビスステアロアミドなど。
【０１９５】
（ｄ）エステル系化合物
脂肪酸の低級アルコールエステル、脂肪酸の多価アルコールエステル、脂肪酸ポリグリコールエステルなど。
【０１９６】
（ｅ）アルコール系化合物
セチルアルコール、ステアリルアルコール、エチレングリコール、ポリエチレングリコール、ポリグリセロールなど。
【０１９７】
（ｆ）金属石けん
ステアリン酸鉛、ステアリン酸カドミウム、ステアリン酸バリウム、ステアリン酸カルシウム、ステアリン酸亜鉛、ステアリン酸マグネシウムなど。
【０１９８】
（ｇ）天然ワックス
カルナバロウ、カンデリラロウ、蜜ロウ、鯨ロウ、イボタロウ、モンタンロウなど。
【０１９９】
（ｈ）その他
シリコーン化合物、フッ素化合物など。
【０２００】
〈紫外線吸収剤〉
紫外線吸収剤は、例えば以下のものが挙げられるが、これらに限定されるものではない。
（ａ）ベンゾフェノン系
２−ヒドロキシベンゾフェノン、２，４−ジヒドロキシベンゾフェノン、２，２' ，４−トリヒドロキシベンゾフェノン、２，２' ，４，４' −テトラヒドロキシベンゾフェノン、２，２' −ジヒドロキシ４−メトキシベンゾフェノンなど。
【０２０１】
（ｂ）サルシレート系
フェニルサルシレート、２，４ジ−ｔ−ブチルフェニル３，５−ジ−ｔ−ブチル４ヒドロキシベンゾエートなど。
【０２０２】
（ｃ）ベンゾトリアゾール系
（２' −ヒドロキシフェニル）ベンゾトリアゾール、（２' −ヒドロキシ５' −メチルフェニル）ベンゾトリアゾール、（２' −ヒドロキシ５' −メチルフェニル）ベンゾトリアゾール、（２' −ヒドロキシ３' −ターシャリブチル５' −メチルフェニル）５−クロロベンゾトリアゾール
【０２０３】
（ｄ）シアノアクリレート系
エチル−２−シアノ−３，３−ジフェニルアクリレート、メチル２−カルボメトキシ３（パラメトキシ）アクリレートなど。
【０２０４】
（ｅ）クエンチャー（金属錯塩系）
ニッケル（２，２' チオビス（４−ｔ−オクチル）フェノレート）ノルマルブチルアミン、ニッケルジブチルジチオカルバメート、ニッケルジブチルジチオカルバメート、コバルトジシクロヘキシルジチオホスフェートなど。
【０２０５】
（ｆ）ＨＡＬＳ（ヒンダードアミン）
ビス（２，２，６，６−テトラメチル−４−ピペリジル）セバケート、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）セバケート、１−［２−〔３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ〕エチル］−４−〔３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ〕−２，２，６，６−テトラメチルピリジン、８−ベンジル−７，７，９，９−テトラメチル−３−オクチル−１，３，８−トリアザスピロ〔４，５〕ウンデカン−２，４−ジオン、４−ベンゾイルオキシ−２，２，６，６−テトラメチルピペリジンなど。
【０２０６】
〈感光体以外の構成、電子写真方法〉
次に、図面を参照しながら電子写真装置の感光体以外の構成と、電子写真方法について詳細に説明する。
上記電子写真装置は、前記したような感光体（電子写真感光体）に、少なくとも帯電、露光、現像を行いトナー画像を形成し、画像保持体（転写紙）へのトナー画像の転写して定着させる。そして、感光体表面のクリーニングを行う。
ただし、このプロセスは、本発明に係る電子写真装置における画像形成プロセスの一例であって、場合によっては、上記プロセスにおいていくつかのステップは省略されてもよく、また別なステップが設けられてもよい。
【０２０７】
図６は、電子写真装置の一構成例を示した概略図である。
図６において、感光体１は前記した感光体が採用される。感光体１は、ドラム状の形状を示しているが、シート状、エンドレスベルト状などの形状であっても良い。
【０２０８】
帯電部材３は、主として帯電ローラーデバイスが用いられ、感光体１と帯電部材とが画像形成領域において非接触で近接配置される。このように、帯電部材を感光体１に近接配置させるには、感光体１の非画像形成領域においてギャップを設ければよい。例えば、ギャップ材を、帯電部材に設けたり、感光体１に設けたり、あるいは感光体の両端にセットされるフランジ部に設ければよい。ただし、感光体１と帯電部材とが近接配置されればどのような構成を採用してもよい。
【０２０９】
図７に、帯電部材にギャップ材を設けた一例を示す。この例では、ギャップ材は、絶縁性を有し、耐摩耗性の高い材料が好ましく用いられる。
ギャップ材は、テープ状、シール状、チューブ状等、どのような形態のものでもよい。
ギャップの厚さは、１０〜２００μｍが好ましく、２０〜１００μｍがより好ましく、さらに好ましくは４０〜８０μｍである。ギャップの厚さをこの範囲内にすると、帯電部材と感光体１とが接触することが極めて少ないため、画質の劣化が極めて少ない。また、帯電の安定性が低下せずに帯電ムラが発生することが極めて少なく、要求される帯電レベルを維持させるための印可電圧を増加させる必要がない。したがって、帯電生成物の発生量を低くできるため、異常画像の発生確率を極めて低くできる。
【０２１０】
また、帯電部材には、直流成分に交流成分を重畳して感光体１に帯電を付与させてもよい。このように交流成分を重畳することで、帯電ムラを低減できる。これにより、画像濃度ムラやコントラストの低下を防止できる。
【０２１１】
画像露光部５は、帯電された感光体１上に静電潜像を形成する。
光源は、例えば、蛍光灯、タングステンランプ、ハロゲンランプ、水銀灯、ナトリウム灯、発光ダイオード（ＬＥＤ）、半導体レーザー（ＬＤ）、エレクトロルミネッセンス（ＥＬ）などの発光物を適宜選択して用いればよい。また、所望の波長域の光のみを照射するために、シャープカットフィルター、バンドパスフィルター、近赤外カットフィルター、ダイクロイックフィルター、干渉フィルター、色温度変換フィルターなどの各種フィルターを用いてもよい。
【０２１２】
現像ユニット６は、感光体１上に形成された静電潜像を可視化する。
現像方式は、乾式トナーを用いた一成分現像法、二成分現像法、湿式トナーを用いた湿式現像法などがある。感光体に正帯電を施し、画像露光を行うと、感光体表面上には正の静電潜像が形成される。これを負極性のトナー（検電微粒子）で現像すれば、ポジ画像が得られるし、また正極性のトナーで現像すれば、ネガ画像が得られる。なお、正負を逆にしてもよい。
【０２１３】
転写チャージャ１０は、感光体１上で可視化されたトナー像を転写体上に転写する。なお、より良好な転写を行うために転写前チャージャ７を用いてもよい。転写方法は、転写チャージャやバイアスローラーを用いる静電転写方法、粘着転写法、圧力転写法等の機械転写方式、磁気転写方法を採用できる。静電転写方法は、帯電手段を用いて実行してもよい。
【０２１４】
分離チャージャ１１、分離爪１２は、転写体を感光体より分離する手段である。その他、分離手段として、静電吸着誘導分離手段、側端ベルト分離手段、先端グリップ搬送手段、曲率分離手段等が用いることもできる。また、分離チャージャは、帯電手段を用いてもよい。
【０２１５】
ファーブラシ１４、クリーニングブレード１５は、転写後感光体上に残されたトナーをクリーニングする。また、クリーニングをより効率的に行うためにクリーニング前チャージャ１３を用いてもよい。
その他、クリーニング方式として、ウェブ方式、マグネットブラシ方式等を採用してもよい。クリーニング方式は任意の一又は複数の方式を採用すればよい。
【０２１６】
除電手段は、感光体１上の潜像を取り除く。除電手段は、例えば、除電ランプ２、除電チャージャが用いられ、それぞれ前記露光光源、帯電手段を利用して実現してもよい。
【０２１７】
原稿読み取り手段、給紙手段、定着手段、排紙手段等は公知のものを採用できる。
また、図６に示す以外の構成／プロセスも当然に採用できる。例えば、図６の構成例では、感光体への光照射工程は、像露光、クリーニング前露光、除電露光することで実現しているが、転写前露光、像露光のプレ露光など公知の光照射工程により感光体に光照射してもよい。
【０２１８】
前記したような画像形成手段は、電子写真装置内に固定して組み込まれていてもよいが、その内の一又は複数は、電子写真装置に着脱可能なプロセスカートリッジに設けられ、プロセスカートリッジが電子写真装置に設置されることで電子写真装置内に組み込まれるようにしてもよい。
図８は、このような電子写真装置用プロセスカートリッジの１構成例を示す。プロセスカートリッジは、感光体（感光体ドラム１０１）を有し、そのほかに帯電手段１０２、現像手段、転写手段１０６、クリーニング手段（クリーニングブレード１０７など）、除電手段などの少なくとも一つが設けられた装置（部品）である。
【０２１９】
（実施例）
以下、実施例により本発明を説明する。ただし、本発明は以下の実施例に限定されて解釈されるものではない。また、以下「部」は重量部を意味する。
【０２２０】
（実施例１）
φ３０ｍｍのアルミニウムドラム（導電性支持体３１）上に、下記組成の下引き層用塗工液、電荷発生層用塗工液、電荷輸送層用塗工液を浸漬塗工法によって順次塗布／乾燥して約３．５μｍの膜厚の下引き層、約０．２μｍの膜厚の電荷発生層３５、約２５μｍの膜厚の電荷輸送層３７を形成し、感光体を作製した。
【０２２１】
〔下引き層用塗工液〕
・アルキッド樹脂 ６部
（ベッコゾール １３０７−６０−ＥＬ，大日本インキ化学工業製）
・メラミン樹脂 ４部
（スーパーベッカミン Ｇ−８２１−６０，大日本インキ化学工業製）
・酸化チタン ４０部
・メチルエチルケトン ５０部
【０２２２】
〔電荷発生層用塗工液〕
・下記一般式（４）で表されるビスアゾ顔料 ２．５部
・ポリビニルブチラール（ＸＹＨＬ，ＵＣＣ製） ０．５部
・シクロヘキサノン ２００部
・メチルエチルケトン ８０部
【０２２３】
〔電荷輸送層用塗工液〕

【０２２４】
【化２３】

【０２２５】
（実施例２）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕

【０２２６】
【化２４】

【０２２７】
（実施例３）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更し、リング塗工法によって電荷輸送層３７を形成した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕

【０２２８】
【化２５】

【０２２９】
（実施例４）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更し、リング塗工法によって電荷輸送層３７を形成した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕

【０２３０】
【化２６】

【０２３１】
（実施例５）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕

【０２３２】
【化２７】

【０２３３】
（実施例６）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更し、リング塗工法によって電荷輸送層３７を形成した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕

【０２３４】
【化２８】

【０２３５】
（実施例７）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕

【０２３６】
【化２９】

【０２３７】
（実施例８）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更し、リング塗工法によって電荷輸送層３７を形成した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕

【０２３８】
【化３０】

【０２３９】
（実施例９）
φ３０ｍｍのアルミニウムドラム（導電性支持体３１）上に、下記組成の下引き層用塗工液、電荷発生層用塗工液、電荷輸送層用塗工液をリング塗工法によって順次塗布／乾燥して、約３．５μｍの膜厚の下引き層、約０．２μｍの膜厚の電荷発生層３５、約２５μｍの膜厚の電荷輸送層３７を形成し、感光体を作製した。
【０２４０】
〔下引き層用塗工液〕
・アルキッド樹脂 ６部
（ベッコゾール １３０７−６０−ＥＬ，大日本インキ化学工業製）
・メラミン樹脂 ４部
（スーパーベッカミン Ｇ−８２１−６０，大日本インキ化学工業製）
・酸化チタン ４０部
・メチルエチルケトン ５０部
【０２４１】
〔電荷発生層用塗工液〕
・図９に示すＸＤスペクトルを有するチタニルフタロシアニン ８部
・ポリビニルブチラール（エスレックＢＭ−Ｓ，積水化学工業製）０．５部
・メチルエチルケトン ４００部
【０２４２】
〔電荷輸送層用塗工液〕

【０２４３】
【化３１】

【０２４４】
（実施例１０）
φ３０ｍｍのアルミニウムドラム（導電性支持体３１）上に、下記組成の下引き層用塗工液、電荷発生層用塗工液、電荷輸送層用塗工液を浸漬塗工法によって順次塗布／乾燥して、約３．５μｍの膜厚の下引き層、約０．２μｍの膜厚の電荷発生層３５、約２０μｍの膜厚の電荷輸送層３７を形成した。電荷輸送層３７上に、下記組成の保護層塗工液をリング塗工法によって塗布／乾燥し、約５μｍの膜厚の保護層３９を形成し、感光体を作製した。
【０２４５】
〔下引き層用塗工液〕
・アルキッド樹脂 ６部
（ベッコゾール １３０７−６０−ＥＬ，大日本インキ化学工業製）
・メラミン樹脂 ４部
（スーパーベッカミン Ｇ−８２１−６０，大日本インキ化学工業製）
・酸化チタン ４０部
・メチルエチルケトン ５０部
【０２４６】
〔電荷発生層用塗工液〕
・下記一般式（４）で表されるビスアゾ顔料 ２．５部
・ポリビニルブチラール（ＸＹＨＬ，ＵＣＣ製） ０．５部
・シクロヘキサノン ２００部
・メチルエチルケトン ８０部
【０２４７】
〔電荷輸送層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・テトラヒドロフラン １００部
・１％シリコーンオイルテトラヒドロフラン溶液 １部
（シリコーンオイル：ＫＦ５０−１００ＣＳ，信越化学工業製）
・下記一般式（６）で表される酸化防止剤（住友化学工業製） ０．１５部
【０２４８】
〔保護層用塗工液〕

【０２４９】
【化３２】

【０２５０】
（実施例１１）
実施例１０において、保護層用塗工液を下記の保護層用塗工液に変更した以外は、実施例１０と同様に感光体を作製した。
〔保護層用塗工液〕

【０２５１】
【化３３】

【０２５２】
（実施例１２）
実施例１０において、保護層用塗工液を下記の保護層用塗工液に変更した以外は、実施例１０と同様に感光体を作製した。
〔保護層用塗工液〕

【０２５３】
【化３４】

【０２５４】
（実施例１３）
実施例１０において、保護層用塗工液を下記の保護層用塗工液に変更し、スプレー塗工によって保護層３９を形成した以外は、実施例１０と同様に感光体を作製した。
〔保護層用塗工液〕

【０２５５】
【化３５】

【０２５６】
（実施例１４）
実施例１０において、保護層用塗工液を下記の保護層用塗工液に変更した以外は、実施例１０と同様に感光体を作製した。
〔保護層用塗工液〕

【０２５７】
【化３６】

【０２５８】
（実施例１５）
実施例１０において、保護層用塗工液を下記の保護層用塗工液に変更し、スプレー塗工によって保護層３９を形成した以外は、実施例１０と同様に感光体を作製した。
〔保護層用塗工液〕

【０２５９】
【化３７】

【０２６０】
（実施例１６）
実施例１０において、保護層用塗工液を下記の保護層用塗工液に変更した以外は、実施例１０と同様に感光体を作製した。
〔保護層用塗工液〕

【０２６１】
【化３８】

【０２６２】
（実施例１７）
φ３０ｍｍのアルミニウムドラム（導電性支持体３１）上に、下記組成の下引き層用塗工液、電荷発生層用塗工液、電荷輸送層用塗工液を浸漬塗工法によって順次塗布／乾燥して、約３．５μｍの膜厚の下引き層、約０．２μｍの膜厚の電荷発生層３５、約２０μｍの膜厚の電荷輸送層３７を形成した。電荷輸送層３７上に、下記組成の保護層塗工液をリング塗工法によって塗布／乾燥して、約５μｍの膜厚の保護層３９を形成し、電子写真感光体１７を作製した。
【０２６３】
〔下引き層用塗工液〕
・アルキッド樹脂 ６部
（ベッコゾール １３０７−６０−ＥＬ，大日本インキ化学工業製）
・メラミン樹脂 ４部
（スーパーベッカミン Ｇ−８２１−６０，大日本インキ化学工業製）
・酸化チタン ４０部
・メチルエチルケトン ５０部
【０２６４】
〔電荷発生層用塗工液〕

【０２６５】
〔電荷輸送層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ８部
・テトラヒドロフラン １００部
・１％シリコーンオイルテトラヒドロフラン溶液 １部
（シリコーンオイル：ＫＦ５０−１００ＣＳ，信越化学工業製）
【０２６６】
〔保護層用塗工液〕

【０２６７】
【化３９】

【０２６８】
（実施例１８）
実施例１７において、保護層用塗工液を下記の保護層用塗工液に変更し、スプレー塗工法によって保護層３９を形成した以外は、実施例１７と同様に感光体を作製した。
〔保護層用塗工液〕

【０２６９】
【化４０】

【０２７０】
（実施例１９）
実施例１７において、保護層用塗工液を下記の保護層用塗工液に変更し、スプレー塗工法によって保護層３９を形成した以外は、実施例１７と同様に感光体を作製した。
〔保護層用塗工液〕

【０２７１】
【化４１】

【０２７２】
（比較例１）
実施例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更した以外は、実施例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・テトラヒドロフラン １００部
・１％シリコーンオイルテトラヒドロフラン溶液 １部
（シリコーンオイル：ＫＦ５０−１００ＣＳ，信越化学工業製）
【０２７３】
【化４２】

【０２７４】
（比較例２）
比較例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更した以外は、比較例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・テトラヒドロフラン １００部
・１％シリコーンオイルテトラヒドロフラン溶液 １部
（シリコーンオイル：ＫＦ５０−１００ＣＳ，信越化学工業製）
・αアルミナ ２部
（スミコランダムＡＡ−０３、平均一次粒径：０．３μｍ、ｐＨ８〜９、住友化学工業製）
・ポリカルボン酸化合物 ０．０５部
（ＢＹＫ−Ｐ１０４、固形分約５０％、ＢＹＫケミー製）
・下記一般式（９）で表される酸化防止剤（住友化学工業製） ０．１部
【０２７５】
【化４３】

【０２７６】
（比較例３）
比較例１において、電荷輸送層用塗工液を下記の電荷輸送層塗工液に変更した以外は、比較例１と同様に感光体を作製した。
〔電荷輸送層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・テトラヒドロフラン １００部
・１％シリコーンオイルテトラヒドロフラン溶液 １部
（シリコーンオイル：ＫＦ５０−１００ＣＳ，信越化学工業製）
・酸化チタン ３．５部
（ＣＲ−ＥＬ、平均一次粒径：０．３μｍ、ｐＨ６〜７、石原産業製）
・ポリカルボン酸化合物 ０．１０部
（ＢＹＫ−Ｐ１０４、固形分約５０％、ＢＹＫケミー製）
・下記一般式（８）で表される酸化防止剤 ０．１５部
（サノールＬＳ−２６２６、三共製）
【０２７７】
【化４４】

【０２７８】
（比較例４）
実施例１０において、保護層用塗工液を下記の保護層用塗工液に変更した以外は、実施例１０と同様に感光体を作製した。
〔保護層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・テトラヒドロフラン １６０部
【０２７９】
【化４５】

【０２８０】
（比較例５）
比較例４において、保護層用塗工液を下記の保護層用塗工液に変更し、スプレー塗工法によって保護層３９を形成した以外は、比較例４と同様に感光体を作製した。
〔保護層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・αアルミナ ３部
（スミコランダムＡＡ−０３、平均一次粒径：０．３μｍ、ｐＨ８〜９、住友化学工業製）
・ポリカルボン酸化合物 ０．０６部
（ＢＹＫ−Ｐ１０４、固形分約５０％、ＢＹＫケミー製）
・テトラヒドロフラン ３５０部
・シクロヘキサノン １００部
・下記一般式（８）で表される酸化防止剤 ０．１５部
（サノールＬＳ−２６２６、三共製）
【０２８１】
【化４６】

【０２８２】
（比較例６）
比較例４において、保護層用塗工液を下記の保護層用塗工液に変更し、スプレー塗工法によって保護層３９を形成した以外は、比較例４と同様に感光体を作製した。
〔保護層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・αアルミナ ５部
（スミコランダムＡＡ−０３、平均一次粒径：０．３μｍ、ｐＨ８〜９、住友化学工業製）
・ポリカルボン酸化合物 ０．１０部
（ＢＹＫ−Ｐ１０４、固形分約５０％、ＢＹＫケミー製）
・テトラヒドロフラン ３５０部
・シクロヘキサノン １００部
・下記一般式（８）で表される酸化防止剤 ０．１５部
（サノールＬＳ−２６２６、三共製）
【０２８３】
【化４７】

【０２８４】
（比較例７）
比較例４において、保護層用塗工液を下記の保護層用塗工液に変更した以外は、比較例４と同様に感光体を作製した。
〔保護層用塗工液〕
・下記一般式（１１）で表される高分子電荷輸送物質 １８部
・αアルミナ ３部
（スミコランダムＡＡ−０３、平均一次粒径：０．３μｍ、ｐＨ８〜９、住友化学工業製）
・ポリカルボン酸化合物 ０．０５部
（ＢＹＫ−Ｐ１０４、固形分約５０％、ＢＹＫケミー製）
・テトラヒドロフラン ３５０部
・シクロヘキサノン １００部
・下記一般式（８）で表される酸化防止剤 ０．１５部
（サノールＬＳ−２６２６、三共製）
【０２８５】
【化４８】

【０２８６】
（比較例８）
比較例４において、保護層用塗工液を下記の保護層用塗工液に変更した以外は、比較例４と同様に感光体を作製した。
〔保護層用塗工液〕
・下記一般式（１１）で表される高分子電荷輸送物質 １８部
・αアルミナ ５部
（スミコランダムＡＡ−０３、平均一次粒径：０．３μｍ、ｐＨ８〜９、住友化学工業製）
・ポリカルボン酸化合物 ０．１０部
（ＢＹＫ−Ｐ１０４、固形分約５０％、ＢＹＫケミー製）
・テトラヒドロフラン ３５０部
・シクロヘキサノン １００部
・下記一般式（８）で表される酸化防止剤 ０．１５部
（サノールＬＳ−２６２６、三共製）
【０２８７】
【化４９】

【０２８８】
（比較例９）
比較例４において、保護層用塗工液を下記の保護層用塗工液に変更し、スプレー塗工法によって保護層３９を形成した以外は、比較例４と同様に感光体を作製した。
〔保護層用塗工液〕
・ビスフェノールＺポリカーボネート １０部
（パンライトＴＳ−２０５０，帝人化成製）
・下記一般式（５）で表される低分子電荷輸送物質 ７部
・αアルミナ ３部
（スミコランダムＡＡ−０３、平均一次粒径：０．３μｍ、ｐＨ８〜９、住友化学工業製）
・ポリカルボン酸化合物 ０．１０部
（ＢＹＫ−Ｐ１０４、固形分約５０％、ＢＹＫケミー製）
・球形シリコーン微粒子 ２部
（平均一次粒径約０．５μｍ、「トスパール１０５」東芝シリコーン製）
・テトラヒドロフラン ３５０部
・シクロヘキサノン １００部
・下記一般式（８）で表される酸化防止剤 ０．１５部
（サノールＬＳ−２６２６、三共製）
【０２８９】
【化５０】

【０２９０】
以上のようにして作製した感光体を、電子写真プロセス用カートリッジ（クリーニング前露光手段がないもの）に装着した。このプロセスカートリッジを、帯電手段が帯電ローラーで、画像露光光源が６５５ｎｍの半導体レーザーを採用した株式会社リコー製、商品名ｉｍａｇｉｏＭＦ２２００の改造機にセットした。また、帯電ローラーの両端部（非画像形成領域）は、５０μｍ厚のテフロン（登録商標）テープを巻き付け固定し、感光体に対し帯電部材を近接配置させた。
【０２９１】
そして、以下のような評価を行った。
（１）２５℃５０％ＲＨ環境下で、初期状態（一回の画像形成後）における画像評価。
（２）３０℃９０％ＲＨ環境下で、初期状態における画像評価。
（３）２５℃５０％ＲＨ環境下で、６万枚の印刷を行った後における画像評価と、感光体の摩耗量の測定。
なお、画像形成は、帯電ローラーにＡＣ（１ｋＨｚ，１．８ｋＶ（peak to peak））＋ＤＣ（−７５０Ｖ）を印加して行った。摩耗量は、初期状態との差を測定した。
（４）３０℃９０％ＲＨ環境下で、（３）と同様に６万枚の印刷を行った後の画像評価と、感光体の摩耗量の測定。
画像評価は、以下の基準で目視により行った。
◎：画質低下が認められず良好なレベル
○：画質低下が認められるが問題のないレベル
△：明らかに画質低下が確認できるレベル
×：画質低下が顕著で画像判別が困難なレベル
結果を表１に示す。
【０２９２】
【表１】

【０２９３】
表１から明らかなように、従来の感光体において、オゾンやＮＯｘの発生量が比較的少ない帯電ローラーを用いても、初期状態では良好な画像が得られたが、高温高湿環境下において繰り返し使用した場合には画質劣化が確認された。
また、フィラーを含まない感光体は、摩耗による膜厚変動量が大きく、地汚れの発生が確認された。
フィラーを含有された感光体は、画像ボケが発生した。フィラーの含有量が多いほど異常画像が発生しやすくなることが確認された。
【０２９４】
一方、上記グラフト共重合体を最表面層に含有された感光体は、フィラーを含まない場合には、従来に比べて摩耗量が低減されたことが確認された。また、６万枚の印刷後においても地汚れの発生が認められなかった。
フィラーを含有された感光体は、良好な画像を初期状態でも６万枚の印刷後でも形成できることが分かった。また、フィラーの添加量を増加させても良好な画像が得られることが分かった。
【０２９５】
以上、この発明の好適な実施の形態を説明したが、上述の実施の形態はこの発明の説明のための例示であって、この実施形態のみにこの発明の範囲を限定する趣旨ではない。当業者は、この発明の要旨を逸脱することなく、種々の変形、改良、修正、簡略化などを上記実施形態に加えた種々の他の形態でもこの発明を実施することができる。
【０２９６】
【発明の効果】
以上の説明から明らかなように、本発明によれば、感光体の最表面層にポリオルガノシロキサン成分を含むコア／シェル構造を有するグラフト共重合体が含有され、かつ、帯電部材が感光体に対して近接配置されているため、オゾンやＮＯｘガスの発生量が極めて少なく、感光体の表面エネルギーや摩擦係数が極めて低く、これらの特徴が長期に渡って安定に維持できるようになった。これにより、例えば、異常画像の発生確率を極めて低くできるようになる。つまり、オゾンなどの発生を抑えることと帯電生成物が感光体へ付着防止を両立し、かつ、この効果を持続させることができるようになった。
【０２９７】
また、最表面層にフィラーを含有させて耐摩耗性が高められた感光体でも異常画像の発生確率を長期に渡って極めて低くできるようになった。これは、表面エネルギーの低減効果の持続性を著しく高めることができるようになったことと、帯電部材を感光体に対して非接触としたために得られた効果である。つまり、従来のように、帯電生成物が感光体に付着することで、特に高温高湿下で異常画像の発生確率が極めて高くなっていた問題を解決した。すなわち、電子写真装置の高耐久化及び高画質化が実現された。
また、最表面層にフィラーが含有されていなくても、感光体の耐摩耗性を高くできるようになった。
【０２９８】
また、感光体のクリーニング性や転写効率の向上でき、フィルミングや異物付着による異常画像が発生してしまうことを抑制でき、放電破壊を抑制でき、耐摩耗性を向上でき、偏摩耗を抑制できるなど、高耐久性と高画質性を備えた電子写真装置を提供できるようになった。また、このような効果が繰り返し使用後においても持続できるようになった。
【０２９９】
また、フィラーに塩基性の金属酸化物を用いたり、フィラーに表面処理を施したり、感光体の最表面層に高分子電荷輸送物質を含有させたり、酸化防止剤等を添加することで、異常画像の発生確率をより低くする（異常画像／画像ボケの影響に対しさらなる余裕度を付与する）ことができるようになった。
【０３００】
また、最表面層にカルボン酸化合物を含有すれば、感光体の静電特性の安定性を高めることが可能となり、極めて良好な高耐久性及び高画質性が実現できた。
【０３０１】
以上のように、本発明による電子写真装置は、ドラムヒーター等の除湿装置を必要とせずに異常画像の発生を抑制可能となったため、小型化や消費電力を低減することが可能となった。
【図面の簡単な説明】
【図１】本発明による電子写真用感光体の層構成例を示す断面図である。
【図２】本発明による電子写真感光体の他の層構成例を示す断面図である。
【図３】本発明による電子写真感光体の他の層構成例を示す断面図である。
【図４】本発明による電子写真感光体の他の層構成例を示す断面図である。
【図５】本発明による電子写真感光体の他の層構成例を示す断面図である。
【図６】本発明による電子写真プロセスカートリッジおよび電子写真装置を示す概略図である。
【図７】本発明による帯電手段と電子写真感光体の位置関係を説明するための図である。
【図８】本発明によるプロセスカートリッジの一構成例を示す概略図である。
【図９】オキシチタニウムフタロシアニンのＸＤスペクトルを示す。
【符号の説明】
１ 感光体
２ 除電ランプ
３ 帯電ローラ
５ 画像露光部
６ 現像ユニット
７ 転写前チャージャ
８ レジストローラ
９ 転写紙
１０ 転写チャージャ
１１ 分離チャージャ
１２ 分離爪
１３ クリーニング前チャージャ
１４ ファーブラシ
１５ クリーニングブラシ
３１ 導電性支持体
３３ 感光層
３５ 電荷発生層
３７ 電荷輸送層
３９ 保護層
１０１ 感光体ドラム
１０２ 帯電装置
１０３ 露光装置
１０４ 現像装置
１０５ 転写体
１０６ 転写装置
１０７ クリーニングブレード[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic apparatus having high durability and improving the stability of image quality over a long period of time.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, electrophotographic apparatuses such as copying machines, facsimile machines, laser printers, and direct digital plate making machines that employ an electrophotographic method have been widely used. In the electrophotographic method, at least charging, image exposure, and development are performed on an electrophotographic photosensitive member, and then a toner image is transferred and fixed on an image holding member (transfer paper). Then, one process is completed by cleaning the surface of the electrophotographic photosensitive member.
[0003]
As a photoreceptor (electrophotographic photoreceptor) used in an electrophotographic apparatus, (1) a photoreceptor provided with a photoconductive layer mainly composed of selenium or a selenium alloy on a conductive support, and (2) zinc oxide / sulfide Known are photoreceptors in which an inorganic photoconductive material such as cadmium is dispersed in a binder, photoreceptors using amorphous silicon materials, and (3) organic photoreceptors. Among these, organic photoconductors are widely used because they have features such as excellent cost and productivity, high degree of freedom in photoconductor design, and non-pollution.
[0004]
Organic photoreceptors are (1) a photoreceptor using a photoconductive resin typified by polyvinyl carbazole (PVK), and (2) PVK-TNF (2,4,7-trinitrofluorenone). Representative charge transfer complex type photoreceptor, (3) Pigment dispersion type photoreceptor represented by phthalocyanine-binder resin, and (4) Function separation type photoreceptor using a combination of a charge generation substance and a charge transport substance. Etc. are known. Of these, a function-separated type photoreceptor is generally used.
[0005]
An example of the electrostatic latent image mechanism in the function-separated type photoreceptor is shown below.
First, the photosensitive member is charged, and then the photosensitive member is irradiated with light. The irradiated light passes through the transparent charge transport layer and is absorbed by the charge generation material in the charge generation layer. The charge generating material that has absorbed the light generates charge carriers. The charge carriers are injected into the charge transport layer, and further move in the charge transport layer according to the electric field to neutralize the charge on the surface of the photoreceptor.
[0006]
The function-separated type photoreceptor forms an electrostatic latent image by the mechanism described above. In order to realize this mechanism, it is known that a charge transport material whose absorption region is mainly in the ultraviolet region may be used in combination with a charge generation material that is mainly in the visible region. Such a photoreceptor is useful because it has excellent image forming properties.
[0007]
Since many charge transport materials have been developed as low molecular weight compounds, they are usually dispersed / mixed in an inert polymer. This is because low molecular weight compounds generally do not have film-forming properties alone / are poor in film-forming properties.
However, a charge transport layer composed of a low molecular charge transport material and an inert polymer is generally soft and has low wear resistance. For example, when it is used repeatedly, film scraping is likely to occur due to a mechanical load on the surface of the photoconductor by a developing system or a cleaning system.
In addition, the charge transport layer having the above structure tends to improve the wear resistance by increasing the ratio of the inert polymer, but the charge mobility is lowered. The content ratio of the inert polymer to the inert polymer is limited, and it has not been realized to dramatically improve the wear resistance.
[0008]
On the other hand, the photosensitive member is required to have a small diameter in order to reduce the size of the electrophotographic apparatus. In order to reduce the diameter of the photoreceptor, it is necessary to increase the durability of the photoreceptor. Furthermore, in recent years, the tendency to increase the printing speed, full color, maintenance-free, etc. has become stronger, and higher durability of the photoreceptor has become an even more important issue.
[0009]
Various conventional techniques have been proposed in response to the above requirements.
For example, in order to improve the wear resistance of the organic photoreceptor, there is a photoreceptor obtained by improving the binder resin of the organic photoreceptor (Japanese Patent Laid-Open No. 5-216250, etc.).
However, since such a photoreceptor has the problem of the composition ratio of the low molecular charge transport material as described above, it is not possible to expect a significant improvement in wear resistance.
[0010]
A photoreceptor using a polymer charge transport material is also known. Such photoconductors are disclosed in, for example, JP-A-51-73888, JP-A-54-8527, JP-A-54-11737, JP-A-56-150749, JP-A-57-57. 78402, JP 63-285552, JP 64-1728, JP 64-13061, JP 64-19049, JP 3-50555, JP JP-A-4-175337, JP-A-4-225014, JP-A-4-230767, JP-A-5-232727, JP-A-5-310904, and the like.
As described above, the photoconductor using the polymer charge transporting material has a charge transport layer component made of a polymer, so that the problem of film abrasion is improved compared to the photoconductor using the conventional low molecular charge transporting material. Yes. However, it is not sufficient to handle the photoconductor as a stationary part that is not replaced until the end of its mechanical life. In other words, maintenance-free is not realized.
[0011]
Also disclosed is a technique for adding an inorganic filler having a relatively high hardness to the outermost surface (layer) of the photoreceptor (Japanese Patent Laid-Open No. 4-281461, etc.).
It is known that this technique can provide a photoconductor with high wear resistance, although the effect of an increase in residual potential increases depending on the filler type to be added.
[0012]
A technique for crosslinking and curing the outermost surface layer of the photoreceptor is also known (Japanese Patent Laid-Open No. 56-48637). Although this technique has side effects such as an increase in residual potential due to the remaining polymerization initiator and unreacted groups, it is known that a photoconductor having high wear resistance can be obtained depending on the crosslinking conditions and the like.
Through the above technical development, the organic photoreceptor has improved wear resistance and high durability.
[0013]
[Problems to be solved by the invention]
However, it has been found that the occurrence of abnormal images such as image blur becomes noticeable when the wear resistance of the photoreceptor is increased.
For example, image blur occurs when the surface resistance of the photoconductor decreases, causing lateral movement of charges and blurring of the electrostatic latent image. The decrease in the surface resistance of the photoconductor is caused by ozone or NOx gas generated when charging the photoconductor and ion species (hereinafter referred to as a charged product) generated by these gases and moisture in the atmosphere. It is considered that the main cause is adhesion and deposition on the top.
[0014]
Conventional photoconductors have low wear resistance, so even if charged products are deposited on the surface of the photoconductor, they are removed by wear. Therefore, the image blur was not noticeable.
On the other hand, it is considered that the image blurring is conspicuous in the photoconductor having high abrasion resistance because it is difficult to remove the charged product.
[0015]
Therefore, it is necessary to suppress the occurrence of abnormal images in order to improve wear resistance / durability. Even if the wear resistance is high, photoconductors that are susceptible to image quality degradation, such as image blurring and resolution reduction, cannot be used in practice, so it cannot be said that high durability has been realized. is there.
[0016]
As described above, as a method for suppressing the influence of ozone and NOx generated by charging, adhesion of charged products, and image blur caused by deposition, the surface energy and friction coefficient of the photoreceptor surface can be reduced, or the outermost surface layer. There is known a method of adding an antioxidant to the toner or providing a dehumidifying device for heating the photoreceptor. Specifically, the following prior art is disclosed.
[0017]
・ Technique for incorporating fluorine-modified silicone oil in the surface layer (Japanese Patent Laid-Open Nos. 07-295248, 07-301936, 08-08940, etc.)
According to this conventional technique, the surface energy of the photoreceptor is reduced, so that the effects of improving the cleaning property and preventing the adhesion of foreign matters can be obtained.
However, the above effects are lost at an early stage, and a big problem remains in the sustainability of the effects. In the case of fluorine-modified silicone oil, the effect of the surface-layer is poor due to the slight wear and charge of the surface layer due to repeated use. One of the reasons is considered to be lost early.
Therefore, it cannot be said that this prior art sufficiently realizes high durability of the photosensitive member.
[0018]
・ Technology related to the addition of various fine particles to the outermost surface layer of the photoreceptor
As such prior art, for example, the following is disclosed.
Technology for adding silicone resin fine particles and fluorine-containing resin fine particles (JP-A 63-65449, etc.)
Technology for adding fine particles of melamine resin (JP-A-60-177349, etc.)
Technology for containing polyethylene powder in the surface layer (Japanese Patent Laid-Open No. 02-143257, etc.)
Technology for containing fluorine-containing resin powder in the surface layer (Japanese Patent Laid-Open No. 02-144550, etc.)
Techniques for incorporating silicone fine particles into the surface layer (Japanese Patent Laid-Open Nos. 07-128872, 10-254160, etc.)
Technology for incorporating cross-linkable organic fine particles into the face layer (Japanese Patent Laid-Open No. 2000-010322, USP 5,998,072 etc.)
Technology for incorporating methylsiloxane resin fine particles into the surface layer (JP 08-190213 A, etc.)
[0019]
These conventional techniques are effective for maintaining the effect of reducing the coefficient of friction on the surface of the photoreceptor or reducing the surface energy, and are effective methods for increasing the durability of the photoreceptor.
However, since such an effect is sustained by the surface of the photoconductor being worn to some extent, the effect is not exhibited in a photoconductor with improved wear resistance.
Further, since the effect is not exhibited at all when the fine particles are covered with the binder resin, it is necessary to wear the surface of the photoreceptor in advance.
Thus, it is difficult to apply the above prior art to a photoconductor with improved wear resistance, and even when applied, it has not been possible to achieve both high durability and high image quality.
[0020]
A technique for adding an antioxidant to the outermost surface layer of the photoreceptor (Japanese Patent Laid-Open No. 8-292585, etc.)
This prior art is an effective method for suppressing the deterioration of the electrostatic characteristics of the photoreceptor due to exposure to ozone or NOx gas.
However, there is a drawback in that the photosensitive member has a strong tendency to increase the residual potential.
Further, since it is necessary to add a relatively large amount of an antioxidant in order to suppress image blurring, the photoreceptor has an extremely high residual potential due to repeated use.
Further, no effect is obtained against image blur due to a charged product adhering to the surface of the photoreceptor, and this method alone is not satisfactory for suppressing image blur.
Therefore, it is difficult to achieve high durability of the photoreceptor only with this conventional technique.
[0021]
Further, as a technique for suppressing image blur due to a charged product adhering to the surface of the photoconductor, a method of heating and dehumidifying the photoconductor is disclosed. This method is an effective method for suppressing image blur because the decrease in resistance on the surface of the photoconductor is suppressed by dehumidifying the photoconductor.
However, this technique has many problems such as extremely high power consumption because it is necessary to constantly heat the photoconductor, and a long time required for starting up the apparatus.
Further, since it is necessary to include a dehumidifying device for heating the photosensitive member in the electrophotographic apparatus, it is difficult to reduce the size of the apparatus.
[0022]
There is also an attempt to solve the above problem depending on the type of charging means employed. This attempt will be described in detail below.
In the electrophotographic apparatus, the charging means includes a corona charging means such as corotron or scorotron for applying charging in a non-contact state to the photosensitive member, and a contact charging such as a charging roller or charging brush for applying charging by contacting the photosensitive member. It is broadly classified into means.
[0023]
Although the corona charging means can be constituted by a simple device, since the generation amount of ozone and NOx is very large, the corona charging means has a great influence (adverse effect) on the environment, electrostatic characteristics and image characteristics of the photoreceptor. In particular, when it is adopted in the tandem system, a plurality of units are required, and the generation amount of ozone and NOx is extremely increased. Therefore, the corona charging means has a very narrow application range in the electrophotographic system.
[0024]
In order to suppress the occurrence of an abnormal image due to the charging means, firstly, it is necessary to reduce the generation amount of ozone and NOx gas. Ozone and NOx gas may alter or decompose the constituent material on the surface of the photoreceptor, which promotes the generation of abnormal images such as reduction in chargeability and wear resistance of the photoreceptor and image blurring. It was the cause. In addition, when a filler or the like is added to the photoconductor to improve the wear resistance, it is also conceivable that the influence of image blur is further increased due to adsorption of ozone or NOx gas to the filler. Therefore, it is necessary to reduce the generation amount of ozone and NOx gas by charging as much as possible.
[0025]
On the other hand, since the charging member such as a charging roller or a charging brush is in contact with the photosensitive member, the contact charging unit can charge the photosensitive member with an applied voltage lower than that of the corona charging unit. Therefore, the generation amount of ozone and NOx can be greatly reduced. Furthermore, it can be said that the charging uniformity is superior to that of the corona charging means, and is an advantageous charging means for improving the durability and image quality of the photoreceptor.
[0026]
However, in the contact charging means, since the charging member is in contact with the photoreceptor, the charging member is contaminated by the adhesion of toner or foreign matter. As a result, for example, the following problems may occur.
・ Deterioration of chargeability of photoconductor due to contamination of charging member.
-Contamination of the surface of the photoreceptor is promoted by re-adhering contaminants attached to the charging member to the photoreceptor.
・ Acceleration of photoconductor wear and uneven wear due to contamination of the charging member.
-Reduction in the removal efficiency of foreign matter on the surface of the photoconductor due to the surface of the photoconductor being pressed by the charging member.
In the contact charging method, the charged product or foreign matter adhering to the surface of the photoreceptor is pressed by the charging member. For this reason, the amount of foreign matter deposited on the surface of the photoconductor is increased as compared with the corona charging method, and the probability of occurrence of image blur and abnormal images is increased.
-Remaining charged roller marks on the photoreceptor.
・ Generation of abnormal images due to deformation of the charging roller.
[0027]
That is, the contact charging method can reduce the generation amount of ozone and NOx gas as compared with the corona charging method, but cannot reduce the probability of occurrence of an abnormal image sufficiently because the accumulation amount of the charged product is not reduced. In other words, the occurrence of abnormal images cannot be suppressed unless the wear rate on the surface of the photoconductor exceeds the deposition rate of the charged product on the photoconductor. That is, in an electrophotographic apparatus that employs a photoconductor having high wear resistance, the probability of occurrence of an abnormal image increases.
[0028]
In view of such a problem, there is a technique in which a charging member is disposed close to a photoreceptor. In this prior art, since the charging member and the photoconductor are not in direct contact with each other in the image forming area, the generation amount of ozone and NOx gas is reduced, and at the same time, the above problems are alleviated and the photoconductor is highly durable and high in image quality. This is an effective method.
Furthermore, the charging member according to the above-described conventional technique is not only easily contaminated but also easily removed even if contaminants adhere to it. Therefore, it can be easily cleaned, and the durability of the photoreceptor can be increased.
[0029]
However, the charging means employing the above-described conventional technology needs to keep the gap between the charging member and the photosensitive member with extremely high accuracy. If the gap between the two cannot be kept, charging stability is lowered.
In order to improve the charging stability, it is sufficient to superimpose an AC component on a DC component. However, this increases the amount of generated charged products, and thus image blurring tends to occur.
Further, since the charging member is disposed close to the photoconductor, discharge breakdown on the surface of the photoconductor is more likely to occur than other charging means. As a result, an abnormal image is likely to occur.
As described above, it is not sufficient to arrange the charging members close to each other in order to suppress the occurrence of an abnormal image and realize high durability of the photosensitive member.
[0030]
In other words, the charging means in which the charging member is disposed close to the photoconductor in the image area (image forming area) has a small amount of contamination of the charging member, and easily removes attached contaminants and charged products. The probability of occurrence of an abnormal image is lower than that of the charging unit.
However, since the photosensitive member and the charging member are not in contact with each other, charging stability is low. In order to increase the charging stability, an AC component must be superimposed, so that the generation amount of the charged product increases, and as a result, the probability of occurrence of an abnormal image increases.
In addition, since the photoreceptor is easily damaged by discharge, there is a problem that it is difficult to obtain a high-quality image.
[0031]
Therefore, the electrophotographic apparatus is (1) maintenance-free by reducing the number of photoconductor replacements, (2) downsizing the apparatus without the need for a dehumidifier, (3) higher image quality, and (4) energy saving. In order to achieve this, it is necessary to increase the wear resistance of the photoreceptor and reduce the probability of occurrence of abnormal images. For this purpose, it is important to suppress the generation amount of ozone and NOx and prevent contamination of the charging member and the photosensitive member.
On the other hand, the charging means in which the charging member is disposed close to the photosensitive member not only has a high probability of occurrence of an abnormal image as described above, but also has a possibility of lowering the image quality due to discharge destruction on the surface of the photosensitive member. There is also.
Therefore, there is a demand for development of an electrophotographic apparatus that can stably provide high-quality images over a long period of time even when a highly durable photoconductor is used. In addition, such an electrophotographic apparatus is desired to further reduce power consumption and downsize the apparatus.
[0032]
The present invention has been made in view of the above problems, and the outermost surface layer of the photoreceptor contains a graft copolymer having a core / shell structure containing a polyorganosiloxane component, and the charging member is disposed close to the photoreceptor. An electrophotographic apparatus that can keep the surface energy low even after repeated use by adopting the charged charging means, and can extremely reduce the probability of occurrence of abnormal images even when a highly durable photoconductor is adopted. The purpose is to do. This electrophotographic apparatus can reduce the accumulation amount of the charged product, can prevent the charging member from being contaminated, and can greatly suppress the contamination of the photosensitive member and the charging member. As a result, the probability of occurrence of abnormal images can be lowered.
[0033]
[Means for Solving the Problems]
In order to achieve the above object, an electrophotographic apparatus according to claim 1 is an electrophotographic apparatus in which at least a charging means, an exposure means, a developing means, and a transfer means are provided around an electrophotographic photosensitive member. The photoreceptor is characterized in that a graft copolymer having a core / shell structure containing a polyorganosiloxane component is contained in the outermost surface layer, and the charging means is disposed in proximity to the electrophotographic photoreceptor.
[0034]
According to a second aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the graft copolymer is obtained by adding a vinyl monomer to a composite rubber having a polyorganosiloxane and a polyalkyl acrylate rubber and / or a polyalkyl methacrylate rubber. It is characterized by being a graft-polymerized graft composite rubber copolymer.
[0035]
According to a third aspect of the present invention, in the electrophotographic apparatus according to the first or second aspect, the graft copolymer contains a polyorganosiloxane component more than the other components.
[0036]
According to a fourth aspect of the present invention, in the electrophotographic apparatus according to any one of the first to third aspects, the graft copolymer has an average particle size in the range of 0.05 μm to 5.0 μm. .
[0037]
The invention according to claim 5 is the electrophotographic apparatus according to any one of claims 1 to 4, wherein the graft copolymer is contained in an amount of 1 to 40% by weight of the total solid content contained in the outermost surface layer. Features.
[0038]
The invention according to claim 6 is the electrophotographic apparatus according to any one of claims 1 to 5, wherein the outermost surface layer contains a kneaded material obtained by melt-kneading the graft copolymer and the binder resin. Features.
[0039]
According to a seventh aspect of the present invention, in the electrophotographic apparatus according to any one of the first to sixth aspects, the charging means is a charging roller.
[0040]
According to an eighth aspect of the present invention, in the electrophotographic apparatus according to the seventh aspect, the charging roller charges the electrophotographic photosensitive member with a voltage in which an alternating current component is superimposed on a direct current component.
[0041]
According to a ninth aspect of the present invention, in the electrophotographic apparatus according to the seventh or eighth aspect, the gap between the charging roller and the image forming region of the electrophotographic photosensitive member is more than 0 μm and not more than 200 μm.
[0042]
According to a tenth aspect of the present invention, in the electrophotographic apparatus according to any one of the first to ninth aspects, the outermost surface layer contains a filler.
[0043]
According to an eleventh aspect of the present invention, in the electrophotographic apparatus according to the tenth aspect, the filler is a metal oxide.
[0044]
The invention according to claim 12 is the electrophotographic apparatus according to claim 11, wherein the metal oxide has a pH at an isoelectric point of 5 or more.
[0045]
A thirteenth aspect of the present invention is the electrophotographic apparatus according to the eleventh or twelfth aspect, wherein the metal oxide is surface-treated.
[0046]
According to a fourteenth aspect of the present invention, in the electrophotographic apparatus according to any one of the tenth to thirteenth aspects, the filler has an average primary particle size in the range of 0.01 μm to 0.9 μm.
[0047]
According to a fifteenth aspect of the present invention, in the electrophotographic apparatus according to any one of the first to fourteenth aspects, the outermost surface layer contains a carboxylic acid compound.
[0048]
According to a sixteenth aspect of the present invention, in the electrophotographic apparatus according to the fifteenth aspect, the carboxylic acid compound is a polycarboxylic acid compound.
[0049]
According to a seventeenth aspect of the present invention, in the electrophotographic apparatus according to any one of the first to sixteenth aspects, the outermost surface layer contains a polymer charge transport material.
[0050]
The invention according to claim 18 is the electrophotographic apparatus according to any one of claims 1 to 17, characterized in that the outermost surface layer contains an antioxidant.
[0051]
According to a nineteenth aspect of the present invention, in the electrophotographic apparatus of the eighteenth aspect, the antioxidant has a hindered amine structure and a hindered phenol structure.
[0052]
According to a twentieth aspect of the present invention, in the electrophotographic apparatus according to any one of the first to nineteenth aspects, at least the charging means and the electrophotographic photosensitive member are provided in a process cartridge that is detachable from the main body of the electrophotographic apparatus. Features.
[0053]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electrophotographic apparatus according to the present invention will be described in detail by embodiments.
[0054]
In the electrophotographic apparatus, the outermost surface layer of the photoreceptor (electrophotographic photoreceptor) contains a graft copolymer having a core / shell structure containing a polyorganosiloxane component, and the charging means is close to the electrophotographic photoreceptor. Has been placed. In this photoreceptor, since the graft copolymer is contained in the outermost surface layer, since the surface energy is low, the charged product is difficult to adhere and the attached charged product is easily removed. Moreover, this effect is stably maintained over a long period of time.
In addition, the transfer efficiency can be made extremely high, the cleaning property can be made extremely high, the probability of occurrence of abnormal images due to filming and foreign matter adhesion can be made extremely low, and the wear resistance can be made extremely high. As a result, an electrophotographic apparatus (photoconductor) having both high durability and high image quality can be provided.
[0055]
The reason why such a sustainable effect is obtained is as follows.
(1) Since the graft copolymer has a shell structure, it has high compatibility with the binder resin that forms the outermost surface layer of the photoreceptor. Therefore, it is considered that the dispersibility and orientation in the outermost surface layer are high.
That is, it is considered that the above effect was obtained even after repeated use because the graft copolymer was dispersed throughout the outermost surface layer.
(2) The graft copolymer has, for example, an internal structure in which a polyorganosiloxane resin portion and an acrylic polymer resin portion are intertwined, and thus the polyorganosiloxane resin portion alone has poor compatibility with the binder resin, It is thought that compatibility was improved by the acrylic resin structure. Therefore, the dispersibility and orientation in the outermost surface layer can be increased, and the composition ratio of the polyorganosiloxane resin portion in the layer can be made extremely, so the above effect is considered to be obtained.
[0056]
In addition, since the above-mentioned graft copolymer was added to the photoreceptor, discharge breakdown was less likely to occur.
The organic group in the photoreceptor generates a carbon residue when it is decomposed by ozone or NOx generated by charging. Since the carbon-based residue is conductive, discharge breakdown is likely to occur.
On the other hand, the graft copolymer has a high binding energy and an insulating Si—O bond. Therefore, since the carbon-based residue also contains Si—O bonds, the probability of occurrence of discharge breakdown can be extremely reduced. Thereby, the occurrence probability of an abnormal image can be made low.
[0057]
In addition, the charging unit has various problems as described above, but when used in combination with the photoconductor, these problems can be solved, and high durability and high image quality of the electrophotographic apparatus can be realized. It was.
In other words, by adopting a charging unit configured not to directly contact (adjacently arrange) the charging member with the photosensitive member in the image forming region, contamination of the charging member can be suppressed. Further, since the surface of the photosensitive member is not worn and the charged products and foreign matters on the surface of the photosensitive member can be easily removed, the contamination amount of the charging member and the photosensitive member can be extremely reduced.
Therefore, transfer efficiency and cleanability can be extremely high, filming and foreign matter adhesion can be suppressed, wear resistance can be improved, uneven wear can be suppressed, contamination of charging members, etc. can be prevented, and discharge breakdown of the photoreceptor can be prevented. As a result, it is possible to reduce the probability of occurrence of abnormal images and to achieve both high durability and high image quality of the apparatus (photoreceptor).
This will be described in detail below.
[0058]
<Graft copolymer>
In the graft copolymer having a core / shell structure, the core portion includes a polyorganosiloxane component, preferably formed of a resilient material, and the shell portion is chemically bonded to the core. The core part is preferably a rubbery polymer shown below. The shell is preferably a vinyl polymer.
[0059]
Rubbery polymer
For example, polybutadiene, styrene-butadiene block copolymer rubber, styrene-butadiene random copolymer rubber, acrylonitrile-butadiene block copolymer rubber, saturated rubber obtained by hydrogenation or partial hydrogenation of these diene rubbers, isoprene rubber, chloroprene rubber, natural rubber , Silicone rubber, ethylene-propylene-diene monomer terpolymer, acrylic rubber, acrylic-silicon composite rubber, etc.
[0060]
These various rubber components may be mixed and used. Silicone rubber, particularly acrylic-silicone composite rubber is preferably used because the obtained photoreceptor (electrophotographic apparatus) can provide extremely excellent durability and image quality.
[0061]
The rubbery polymer is preferably formed by emulsion polymerization.
Moreover, a crosslinkable monomer can also be used for a rubber-like polymer. Examples of the crosslinkable monomer include aromatic divinyl compounds such as divinylbenzene, alkane polyol polyacrylates such as ethylene glycol diacrylate and ethylene glycol dimethacrylate, and acrylic compounds such as alkane polyol polymethacrylate and allyl methacrylate. .
[0062]
The acrylic-silicon composite rubber is a composite rubber having a structure in which a polyorganosiloxane rubber component and a polyalkyl acrylate rubber component and / or a polyalkyl methacrylate rubber component are intertwined with each other so that they cannot be separated. More specifically, it is a rubber that can be produced by the following steps (1) to (2). (1) Various organoorganosiloxanes having three or more members such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, etc. are polyorganopolymerized by emulsion polymerization using a crosslinking agent and / or a graft crossing agent. Adjust latex of siloxane rubber. (2) The polyorganosiloxane rubber latex is impregnated with an alkyl acrylate monomer and / or an alkyl methacrylate monomer, a crosslinking agent and a graft crossing agent, and then polymerized.
[0063]
Examples of the alkyl acrylate monomer / alkyl methacrylate monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, alkyl acrylate such as 2-ethylhexyl acrylate, hexyl methacrylate, and 2-ethylhexyl methacrylate. Although alkyl methacrylate is mentioned, n-butyl acrylate is preferably used.
[0064]
In the composite rubber, two kinds of rubbers are used in the range of 10 to 90% by weight, preferably 20 to 80% by weight, based on the total amount of both rubber components.
If the polyorganosiloxane rubber component is contained in an amount exceeding 90% by weight based on the total amount of both rubber components, the surface appearance of the outermost surface layer is deteriorated. Further, when the polyalkyl acrylate rubber component and the polyalkyl methacrylate rubber component are contained in an amount exceeding 90% by weight, the abrasion resistance and impact resistance of the photoreceptor are lowered.
[0065]
The average particle size of the composite rubber is 0.01 to 1.0 μm, preferably 0.08 to 0.6 μm. When the average particle diameter is less than 0.01 μm, the photoconductor is inferior in cleaning property. When the thickness is larger than 1.0 μm, the cleaning property is inferior and the surface appearance is poor.
[0066]
In addition, although a well-known method can be employ | adopted for the manufacturing method of acrylic-silicon composite rubber, For example, the method of Japanese Patent Publication No.8-30102 can also be used suitably.
[0067]
The graft copolymer can be obtained by one-step or multi-step radical polymerization of one or two or more types of vinyl monomers to the various rubber-like polymers obtained as described above. In addition, you may use the mixture with the copolymer of only the graft component byproduced in the case of manufacture.
[0068]
Examples of vinyl monomers include aromatic vinyl such as styrene, α-methylstyrene, methyl (o-, m-, p-) styrene, ethylstyrene, isobutylstyrene, tert-butylstyrene, bromostyrene, and vinylnaphthalene. Compounds, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, methyl methacrylate, 2-ethylhexyl methacrylate, ethyl methacrylate, propyl methacrylate, hydroxyethyl methacrylate, cyclohexyl methacrylate, alkyl methacrylate such as butyl methacrylate, methyl acrylate, ethyl acrylate, Acrylic acid esters such as butyl acrylate are listed. These compounds may be used alone or in combination of two or more.
[0069]
As described above, the graft copolymer obtained by radical polymerization of one or more vinyl monomers in one or more stages to the acrylic-silicon composite rubber is compatible in the outermost surface layer. Since the dispersibility is very good and the surface energy of the obtained photoreceptor can be kept low, it is preferably used. Such a composite rubber core / shell copolymer can be produced by the method as described above. For example, those produced by the method described in JP-B-8-30102 can be preferably used.
[0070]
The core part (rubbery polymer) is 30 to 95 parts by weight, preferably 40 to 90 parts by weight of the core layer, with the total amount of the graft copolymer being 100 parts by weight. The shell part (vinyl monomer) is 5 to 70 parts by weight, preferably 10 to 60 parts by weight, with the total amount of the graft copolymer being 100 parts by weight. When the shell part is less than 5 parts by weight, the graft copolymer is not sufficiently dispersed in the resin (binder resin), and when it exceeds 70 parts by weight, a photoreceptor having a sufficiently low surface energy cannot be obtained. Therefore, it is not preferable.
[0071]
The graft copolymer preferably has an average particle size in the range of 0.05 to 5 μm. If it is less than 0.05 μm, sufficient cleaning properties cannot be obtained, and if it exceeds 5 μm, the appearance of the outermost surface layer is deteriorated and image defects may be caused (abnormal images are liable to occur).
[0072]
It should be noted that impurities such as an emulsifier and an aggregating agent used at the time of polymerization may impair the electrical characteristics of the image forming member, particularly the photoreceptor, and therefore it is preferable to purify and remove as necessary. As the purification method, a method of stirring and washing with an acid, an aqueous alkali solution, water, alcohol or the like, or a solid-liquid extraction method such as Soxhlet extraction can be employed.
[0073]
As the graft copolymer, a product name Metabrene S grade manufactured by Mitsubishi Rayon Co., Ltd., which can obtain a photoreceptor (electrophotographic apparatus) that does not deteriorate good durability and image quality even after repeated use, is preferably used. Among them, the trade name SX-005 is particularly preferably used because a photoreceptor (electrophotographic apparatus) having extremely excellent durability, image quality, and sustainability of these properties can be obtained.
[0074]
<Example of layer structure>
The aforementioned graft copolymer may be contained in the outermost surface layer of the photoreceptor. The surface of the photoreceptor means a surface on which a latent image is formed, that is, a surface facing the charging unit. That is, the graft copolymer is contained within a certain distance from the surface of the photoreceptor.
The outermost surface layer contains a substance other than the graft copolymer, and an arbitrary function may be added. For example, a filler or an antioxidant may be added. Also, the depth (layer thickness) of the outermost layer and the thickness of the outermost layer among the layers classified by functions in the photoreceptor (protective layer, charge transport layer, charge generation layer, etc.) , May be the same or different.
Hereinafter, the relationship between the layer configuration example of the photoreceptor and the range (outermost surface layer) in which the graft copolymer is contained is shown in FIGS.
[0075]
In the photoreceptor shown in FIG. 1, a photosensitive layer 33 is formed on a conductive support 31. The photosensitive layer 33 is mainly composed of a charge generation material and a binder resin.
In FIG. 1, the surface is the surface of the photosensitive layer 33 that is not in contact with the conductive support 31.
The graft copolymer is included in a range from the surface (photosensitive layer 33 side) to an arbitrary position. For example, as shown in FIG. 1B, it may be contained in a part of the surface side of the photosensitive layer 33, and as shown in FIG. 1A, it is contained in the entire photosensitive layer 33 (entire range). May be. Further, it may be contained in part or all of the conductive support 31 on the photosensitive layer 33 side.
[0076]
The photoreceptor shown in FIG. 2 has a configuration in which a charge generation layer 35 and a charge transport layer 37 are sequentially laminated on a conductive support 31. The charge generation layer 35 is mainly composed of a charge generation material. The charge transport layer 37 is mainly composed of a charge transport material.
In FIG. 2, the surface is the surface of the charge transport layer 37 that is not in contact with the charge generation layer 35.
The graft copolymer is included in a range from the surface to an arbitrary position. For example, as shown in FIG. 2B, it may be contained in a part of the charge transport layer 37. Moreover, as shown to Fig.2 (a), you may contain in the whole (all range) of the electric charge transport layer 37. FIG. In this case, the charge generation layer 35 may also be included in a part or all (all range) from the charge transport layer 37. Further, it may be contained in a part or the entire range of the conductive support 31.
[0077]
The photoconductor shown in FIG. 3 has a configuration in which a protective layer 39 is further laminated on the surface side of the photoconductive layer 33 in the photoconductor shown in FIG.
In FIG. 3, the surface is the surface of the protective layer 39 that is not in contact with the photosensitive layer 33.
The graft copolymer is included in a range from the surface to an arbitrary position. For example, as shown in FIG. 3, the protective layer 39 may be contained in the entire region.
[0078]
The photoreceptor shown in FIG. 4 has a configuration in which a protective layer 39 is further laminated on the surface side of the charge transport layer 37 in the photoreceptor shown in FIG.
In FIG. 4, the surface is a surface of the protective layer 39 that is not in contact with the charge transport layer 37.
The graft copolymer is included in a range from the surface to an arbitrary position. For example, as shown in FIG. 4, the protective layer 39 may be contained in the entire region.
[0079]
The photoconductor shown in FIG. 5 has a structure in which a charge transport layer 37, a charge generation layer 35, and a protective layer 39 are sequentially laminated on a conductive support 31.
In FIG. 5, the surface is a surface of the protective layer 39 that is not in contact with the charge generation layer 35.
The graft copolymer is included in a range from the surface to an arbitrary position. For example, as shown in FIG. 5, it may be contained throughout the protective layer 39.
Next, the outermost surface layer will be described.
[0080]
<Outermost surface layer>
The outermost surface layer is a region containing a graft copolymer as shown in FIGS.
The outermost surface layer is obtained by dissolving or dispersing the graft copolymer in a solvent or dispersion medium together with the outermost surface layer forming binder resin as necessary, and coating the obtained coating liquid on the coated layer. Can be obtained.
When the outermost surface layer has a role such as the photosensitive layer 33 or the protective layer 39, a material corresponding to this role is also dissolved or dispersed in the solvent or dispersion medium to obtain a coating solution. For example, when the entire area of the photosensitive layer 33 is the outermost surface layer as shown in FIG. 1 (a), a material for forming the photosensitive layer 33 described later is also dissolved or dispersed in the solvent or dispersion medium to form a coating solution. Get. In other words, what is necessary is just to apply | coat the coating liquid which melt | dissolved or disperse | distributed the graft copolymer to the coating liquid for layer formation used as an outermost surface layer.
[0081]
Any solvent or dispersion medium for forming the outermost surface layer may be used as long as it can dissolve or disperse the graft copolymer well. For example, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate and the like can be mentioned.
As the dissolution method / dispersion method, a method using a ball mill, a method using an attritor, a method using a sand mill, a method using a bead mill, a method using ultrasonic waves, and the like can be adopted.
The coating solution may be appropriately diluted with a solution or dispersion containing at least a binder resin.
[0082]
Moreover, the method of forming the outermost surface layer by mechanically mixing the above-described materials using a known apparatus such as a Banbury mixer, a roll mill, or a twin screw extruder to form a pellet shape can be employed. Extruded pellets can be molded over a wide temperature range, and a normal injection molding machine is used for molding. The graft copolymer having a graft copolymer shaped into a pellet and the resin may be dissolved or dispersed in a solvent or a dispersion medium as described above and applied onto the coating layer.
[0083]
In particular, when the graft copolymer is melt-kneaded with the binder resin, the dispersibility in the binder resin becomes extremely high, and deagglomeration is greatly promoted. As a result, it is possible to provide a photoreceptor that has extremely high surface smoothness, hardly causes coating film defects, and stably maintains the friction coefficient and surface energy in a very low state.
[0084]
The graft copolymer in the outermost surface layer is contained in the range of 1% by weight to 40% by weight, preferably in the range of 5% by weight to 20% by weight, based on the total solid content of the outermost surface layer. If the content is within this range, a state where the surface energy on the surface of the photoconductor is low can be stably maintained for a long period of time as compared with a photoconductor having a content less than the above range. In addition, it is possible to stably maintain a state in which the occurrence probability of an abnormal image is extremely low for a long time. Furthermore, it has been found that the probability of occurrence of coating film defects is extremely low compared to a photoreceptor having a content larger than the above range, and good surface smoothness can be obtained.
[0085]
Further, as shown in FIG. 1B and FIG. 2B, in order to make a part (surface side) of the photosensitive layer 33 and the charge transport layer 37 as the outermost surface layer, these layers are formed by a known method. The concentration gradient may be imparted so that the concentration on the surface side of the graft copolymer is increased. With such a configuration, good resolution may be obtained and the adhesion performance between the films may be excellent.
[0086]
The outermost surface layer may contain a filler (material) in order to improve wear resistance.
Filler materials include organic fillers and inorganic fillers.
[0087]
Examples of the organic filler material include a fluororesin powder such as polytetrafluoroethylene, a silicone resin powder, and an a-carbon powder.
Inorganic filler material, for example, metal powder such as copper, tin, aluminum, indium, silica, tin oxide, zinc oxide, titanium oxide, alumina, zirconia, indium oxide, antimony oxide, bismuth oxide, calcium oxide, antimony dope And metal oxides such as tin oxide, tin-doped indium oxide, metal fluorides such as tin fluoride, calcium fluoride, and aluminum fluoride, and inorganic materials such as potassium titanate and boron nitride.
Among these materials, inorganic materials having relatively high filler hardness are preferably used from the viewpoint of wear resistance, and metal oxides are particularly preferably used from the viewpoint of light transmission and coating film quality. Since a decrease in light transmittance and coating film quality greatly affects the image quality, it is important to select a material that has little adverse effect on light transmission and coating film quality in order to achieve high image quality.
[0088]
A metal oxide filler having high electrical insulation is preferably used because the probability of occurrence of abnormal images can be extremely reduced. This is because if the outermost surface layer contains a conductive filler, the surface resistance is lowered, so that lateral movement of charges occurs, and abnormal images such as image blurring are likely to occur.
Therefore, the specific resistance is 10 ^Ten A filler material of Ω · cm or more is preferably used. Examples of such filler materials include alumina, zirconia, titanium oxide, silica, and the like.
On the other hand, the specific resistance is 10 ^Ten Examples of conductive fillers of Ω · cm or less and fillers with relatively low specific resistance include tin oxide, zinc oxide, acid value indium, acid value antimony, antimony-doped tin oxide, and tin-doped indium oxide. This is not preferable because the probability of occurrence of abnormal images increases. However, even if the filler is the same material, the specific resistance may be different. Therefore, the filler material to be employed is selected depending on the specific resistance.
[0089]
In addition, you may use the above filler materials in mixture of 2 or more types. In this case, it is only necessary that the mixture of filler materials employed has the above-described specific resistance. That is, a filler material having no specific resistance as described above can also be used.
[0090]
The filler material preferably has a pH at an isoelectric point of at least 5 or more in order to reduce the probability of occurrence of abnormal images. In addition, the more basic, the lower the probability of occurrence of an abnormal image.
Since the filler dispersed in the liquid is charged, the stability of the filler particles and the resolution of the photoreceptor may be affected. On the other hand, the filler material as described above is preferably used because such problems are extremely small.
Examples of such filler materials include titanium oxide, zirconia, and alumina. Also, alumina is particularly preferably used because the basicity increases in the order of titanium oxide <zirconia <alumina. Furthermore, α-type alumina with a hexagonal close-packed structure, which can provide a photoconductor with high light transmission, high thermal stability, and excellent wear resistance, has a low probability of abnormal images and high wear resistance. Since it is possible to provide a photoreceptor having good coating quality and light transmittance, it is very preferably used.
[0091]
The filler material may be surface-treated with at least one surface treatment agent.
An abnormal image may occur when ozone or NOx gas is exposed to the filler material on the surface of the photoreceptor. Therefore, the specific resistance of the filler and the pH at the isoelectric point are changed by the surface treatment agent, so that the probability of occurrence of an abnormal image can be made extremely small as compared with the case where the filler material not subjected to the surface treatment is adopted. Depending on the surface treatment method (surface treatment agent) used, the dispersibility of the filler material in the outermost surface layer can be improved, the transparency of the coating film (outermost surface layer) can be improved, or coating film defects can occur. Various effects can be obtained, such as suppressing the wear, improving the wear resistance of the photoreceptor, and suppressing uneven wear.
[0092]
As the surface treating agent, all conventionally used surface treating agents can be used, but a surface treating agent that can make the specific resistance of the filler and the pH at the isoelectric point as described above is preferably used.
The pH at the isoelectric point of the filler can be adjusted by surface treatment. The treatment with an acidic treatment agent moves the isoelectric point to the acidic side, and the treatment with a basic treatment agent moves the isoelectric point to the basic side, so a basic treatment agent is preferably used. As the basic treatment agent, for example, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents and the like are preferably used. Al ₂ O _Three TiO ₂ , ZrO ₂ Silicone, aluminum stearate, or the like, or a mixture thereof is also preferably used because it can increase the dispersibility of the filler on the outermost surface layer and reduce the probability of occurrence of abnormal images on the obtained photoreceptor. The treatment with the silane coupling agent increases the probability of occurrence of abnormal images, but there are cases where the influence can be reduced by performing the above-described mixing treatment of the surface treatment agent and the silane coupling agent.
In addition, when a basic treatment agent is used, it may be possible to employ a filler having a pH at the isoelectric point of the filler of 5 or less.
[0093]
The average primary particle size of the filler is preferably from 0.01 to 0.9 μm, more preferably from 0.1 to 0.5 μm. When the average primary particle size of the filler is within the above range, the light transmittance is kept good, and there is little adverse effect on the wear resistance and coating quality. When the average primary particle size of the filler is smaller than the above range, the filler is likely to aggregate, the wear resistance is lowered, and the specific surface area of the filler is increased, so that the probability of occurrence of an abnormal image is increased. When the average primary particle size of the filler exceeds the above range, the sedimentation property of the filler is promoted, and the probability of image quality deterioration or abnormal image generation increases.
[0094]
In order to suppress an increase in residual potential caused by the inclusion of the filler material, it is preferable to add one kind of carboxylic acid compound.
The carboxylic acid compound may be one having a non-volatile content of 100% or one previously dissolved in an organic solvent or the like.
[0095]
Any carboxylic acid compound can be used as long as it is a compound containing a carboxyl group in its molecular structure, such as a known organic fatty acid, high acid value resin, and copolymer. For example, saturated fatty acids such as lauric acid, stearic acid, arachidic acid, behenic acid, adipic acid, oleic acid, maleic acid, maleic anhydride, salicylic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, unsaturated fatty acids, An aromatic carboxylic acid etc. are mentioned. Also, saturated polyester, unsaturated polyester, terminal carboxylic acid unsaturated polyester, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene-acrylic acid copolymer, styrene-acrylic acid-acrylic ester copolymer, Styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-maleic acid copolymers, styrene-maleic anhydride, and the like can also be suitably used. In other words, a polymer, oligomer or copolymer having a saturated or unsaturated hydrocarbon as the basic skeleton and at least one carboxyl group bonded to this basic skeleton has the effect of suppressing residual potential rise, and the dispersibility of the filler It is preferably used for improving.
[0096]
Among them, the polycarboxylic acid compound having a plurality of carboxylic acid residues has a high acid value and high adsorptivity to the filler, so that the residual potential can be lowered and the dispersibility in the outermost surface layer of the filler can be increased. Particularly preferably used. Among such polycarboxylic acid compounds, a polycarboxylic acid type wetting and dispersing agent is extremely preferable. For example, a trade name “BYK-P104” manufactured by BYK Chemie is particularly effectively used.
[0097]
The reason why the residual potential of the outermost surface layer can be lowered (can be kept / reduced) by containing the carboxylic acid compound as described above is that the carboxylic acid compound has an acid value and has an adsorptivity to the filler. This is probably because of this.
It is considered that by adding a filler to the outermost surface layer, the polar group on the filler surface becomes a charge trap site, so that the residual potential is increased. On the other hand, it is considered that the carboxylic acid compound reduces the residual potential of the outermost surface layer because the carboxyl group is easily adsorbed to the polar group.
In addition, the carboxylic acid compound increases the wettability by giving affinity to both the filler and the binder resin, and also reduces the interaction between the fillers to give steric hindrance and electrical repulsion, thereby improving stability. In order to increase, it is thought that the dispersibility in the outermost surface layer of a filler is improved.
The carboxylic acid compound also has an effect of improving dispersibility in the outermost surface layer of the graft copolymer. Since the graft copolymer contains an acrylic structure in the molecular structure, it is considered that the graft copolymer has a high affinity with the carboxylic acid compound and has a high dispersibility in the outermost surface layer. As a result, the coating film quality can be improved, and the stabilization of the image quality is realized.
[0098]
It is preferable to add an antioxidant to the outermost surface layer of the photoreceptor.
Antioxidants include, for example, phenolic compounds, hindered phenolic compounds, hindered amine compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, organic phosphorus compounds, benzophenones, salsylates, benzotriazoles All known antioxidants such as citrates and quenchers (metal complex salts) can be used. Moreover, an ultraviolet absorber, a light stabilizer, etc. can be used.
[0099]
Among the antioxidants, compounds having a hindered phenol structure and a hindered amine structure have a high effect of preventing / suppressing deterioration of the photoreceptor from active gases such as ozone and NOx and improving image quality stability.
[0100]
The hindered phenol structure is a structure in which bulky atomic groups exist at both ortho positions of the phenolic hydroxyl group.
The hindered amine structure is a structure in which a bulky atomic group exists in the vicinity of the amino nitrogen atom. The compound having such a structure corresponds to an aromatic amine or an aliphatic amine-based substance, but a compound containing a 2,2,6,6-tetramethylpiperidine structure is more preferably used.
Although the details of the mechanism of action of compounds having both these structures are not clear, the presence of bulky atomic groups enhances steric hindrance, suppresses thermal vibration of amino nitrogen atoms and phenolic hydroxyl groups, It is thought that stability is improved. Thereby, it is estimated that the influence of the active gas from the outside was able to be stopped.
[0101]
Examples of the compound having both a hindered phenol structure and a hindered amine structure include various compounds. Among them, 1- [2- [3- (3,5-di-t] represented by the following structural formula (3) is available. -Butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpyridine However, it is effective in preventing resolution reduction of the photoreceptor due to ozone or NOx gas.
[0102]
[Chemical 1]

[0103]
The photoconductor may be reduced in chargeability or wear resistance due to exposure to ozone or NOx gas, but the electrostatic characteristics are stabilized by adding an antioxidant. That is, stabilization of image quality during long-term repeated use is realized.
[0104]
In addition, when a filler is added to the outermost surface layer, ozone or NOx gas components are easily adsorbed by the filler, so that the influence of image blur is slightly increased as compared to the case where there is no filler. On the other hand, it has been found that when an antioxidant having both a hindered phenol structure and a hindered amine structure is contained together with a filler, the occurrence probability of an abnormal image can be extremely lowered.
In other words, by using a combination of the filler and the antioxidant, the probability of occurrence of an abnormal image can be extremely lowered, so that higher image quality can be realized.
[0105]
Further, when the content of the graft copolymer in the outermost surface layer is large, the chargeability of the obtained photoreceptor (outermost surface layer) may be lowered. In particular, this phenomenon becomes stronger when ozone or NOx gas is exposed. On the other hand, this can be prevented by adding these antioxidants to the outermost surface layer of the photoreceptor. This highly effective antioxidant is 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpyridine.
[0106]
Next, each layer of the photoreceptor will be described. As described above, each of the layers described below may be the outermost surface layer (may contain the graft copolymer in the entire region) or a part of the outermost layer. Also good. Further, layers other than those described below may be provided.
[0107]
<Conductive support 31>
The conductive support 31 is a layer that serves as a base for supporting each layer such as the photosensitive layer 33 and has a volume resistance of 10. ^Ten It is a layer showing conductivity of Ω · cm or less.
As the conductive support 31, for example, the following can be adopted.
・ Metal oxide such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, and metal oxides such as tin oxide and indium oxide are coated on film or cylindrical plastic or paper by vapor deposition or sputtering. What
-Plates made of aluminum, aluminum alloy, nickel, stainless steel, etc.
・ A tube that has been subjected to surface treatment such as extrusion / pulling, cutting / superfinishing / polishing of aluminum, aluminum alloy, nickel, stainless steel, etc.
-Endless nickel belts, endless stainless steel belts, etc. (described in JP-A-52-36016).
[0108]
Moreover, what spread | dispersed and apply | coated conductive powder to appropriate binder resin (binder resin for the conductive support bodies 31) on arbitrary support bodies can also be used as the conductive support body 31. FIG. . That is, the conductive powder and the binder resin can be dissolved or dispersed in an appropriate solvent or dispersion medium to prepare a coating liquid, and this coating liquid can be applied on the support.
Examples of the conductive powder include metal powders such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, metal oxide powders such as conductive tin oxide and ITO, carbon black, and acetylene black.
Examples of the binder resin in which the conductive powder is dispersed include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, and vinyl chloride-acetic acid. Vinyl copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin , Epoxy resins, melamine resins, urethane resins, phenol resins, alkyd resins, and other thermoplastic resins, thermosetting resins, and photocurable resins.
Examples of the solvent or dispersion medium for dissolving or dispersing the conductive powder and the binder resin include tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
[0109]
A heat-shrinkable tube such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, or Teflon (registered trademark) containing the above conductive powder was coated on a suitable cylindrical substrate. Goods (those provided with a conductive layer) can also be used favorably as the conductive support 31.
[0110]
<Laminated Photosensitive Layer 33>
The photosensitive layer 33 includes a single layer type as shown in FIG. 1 and a laminated type as shown in FIG. First, the laminated photosensitive layer 33 will be described. The stacked photosensitive layer 33 includes a charge generation layer 35 and a charge transport layer 37.
[0111]
<Charge generation layer 35>
The charge generation layer 35 is mainly composed of a charge generation material, and also contains a binder resin (a binder resin for forming the charge generation layer 35) as necessary. Optional additives are also included.
[0112]
As the charge generation material, an inorganic material or an organic material may be used.
Examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, cadmium sulfide, cadmium sulfide-selenium, amorphous silicon, and the like. As amorphous silicon, dangling bonds terminated with hydrogen atoms or halogen atoms or those doped with boron atoms, phosphorus atoms or the like are preferably used.
[0113]
A known material can be adopted as the organic material. For example, disazo pigments, asymmetrical disazo pigments, trisazo pigments, azo pigments having a carbazole skeleton (described in JP-A-53-95033), azo pigments having a distyrylbenzene skeleton (JP-A-53-133445) ), An azo pigment having a triphenylamine skeleton (described in JP-A No. 53-132347), an azo pigment having a diphenylamine skeleton, an azo pigment having a dibenzothiophene skeleton (described in JP-A No. 54-21728), An azo pigment having a fluorenone skeleton (described in JP-A No. 54-22834), an azo pigment having an oxadiazol skeleton (described in JP-A No. 54-12742), an azo pigment having a bis-stilbene skeleton (JP Described in JP 54-17733), an azo face having a distyryl oxadiazol skeleton (Described in JP-A No. 54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A No. 54-14967), azulenium salt pigments, squaric acid methine Pigment, perylene pigment, anthraquinone pigment, polycyclic quinone pigment, quinoneimine pigment, diphenylmethane pigment, triphenylmethane pigment, benzoquinone pigment, naphthoquinone pigment, cyanine pigment, azomethine pigment, indigoid pigment, Examples thereof include bisbenzimidazole pigments, phthalocyanine pigments such as metal phthalocyanines and metal-free phthalocyanines represented by the following general formula (N).
These charge generation materials may be used alone or in combination of two or more.
[0114]
[Chemical 2]

[0115]
In the above general formula (N), M (center metal) represents a metal and a metal-free (hydrogen) element. M (central metal) is H, Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y , Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, TI, La, Ce , Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Pa, U, Np, Am, etc., and oxides of these elements , Chloride, fluoride, hydroxide, bromide and the like, but are not limited thereto.
In addition, the compound represented by the general formula (N) may have a multimeric structure such as a dimer or a trimer, or may have a higher order polymer structure. Further, the basic skeleton represented by the general formula (N) may have various substituents.
[0116]
Note that oxotitanium phthalocyanine, metal-free phthalocyanine, chlorogallium phthalocyanine, and the like having TiO as a central metal are preferably used because good photoreceptor characteristics (charge generation, etc.) can be obtained.
In addition, phthalocyanine is known to have various crystal systems. For example, in the case of oxotitanium phthalocyanine, α, β, γ, m, Y type, etc., in the case of copper phthalocyanine, crystals such as α, β, γ, etc. Has a multisystem. Various characteristics of phthalocyanines having the same central metal also change as the crystal system changes. It has been reported that the characteristics of photoreceptors using phthalocyanine pigments having these various crystal systems also change accordingly (Electrophotographic Society Vol. 29, No. 4 (1990)). Thus, the selection of the phthalocyanine crystal system is very important in terms of the photoreceptor characteristics. Among them, it is known that a photoreceptor containing Y-type oxotitanium phthalocyanine is effective for increasing sensitivity.
[0117]
Examples of the binder resin for forming the charge generation layer 35 include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, Examples include polystyrene, poly-N-vinylcarbazole, polyacrylamide and the like. These binder resins may be used alone or as a mixture of two or more.
[0118]
In addition, as a binder resin for forming the charge generation layer 35, a polymer charge transport material described later (for example, JP-A 64-1728, JP-A 64-13061, JP-A 64-19049, JP-A-4-11627, JP-A-4-225014, JP-A-4-230767, JP-A-4-320420, JP-A-5-232727, JP-A-6-234838, JP JP-A-6-234839, JP-A-6-295077, JP-A-7-56374, JP-A-7-325409, JP-A-9-80772, JP-A-9-80783, JP-A-9- No. 80784, JP-A-9-127713, JP-A-9-21877, JP-A-9-222740, JP-A-9-265197, Rights 9-265201, JP-A No. 9-297419 and JP-matter of JP-A 9-304956 JP) can also be used.
[0119]
The binder resin for forming the charge generation layer 35 is contained in an amount of more than 0 parts by weight and less than 500 parts by weight, preferably more than 0 parts by weight and less than 200 parts by weight with respect to 100 parts by weight of the charge generation material. .
Moreover, various additives, such as leveling agents, such as a dimethyl silicone oil and a methyl phenyl silicone oil, a sensitizer, and a dispersing agent, can be added as needed.
[0120]
As a method for forming the charge generation layer 35, a vacuum thin film manufacturing method may be employed, or a casting method from a solution dispersion system may be employed.
Vacuum thin film preparation methods include vacuum deposition, glow discharge decomposition, ion plating, sputtering, reactive sputtering, CVD, etc., when inorganic charge generation materials and organic charge generation materials are used It is used well.
In the casting method, for example, the charge transport layer 37 is formed as follows. First, an inorganic charge generation material or an organic charge generation material, together with a binder resin, if necessary, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, methyl ethyl ketone Then, it is dissolved or dispersed in a solvent or dispersion medium such as acetone, ethyl acetate or butyl acetate by a ball mill, an attritor, a sand mill, a bead mill or the like to obtain a coating solution. And it can form by diluting this coating liquid moderately and apply | coating on a to-be-coated layer. For coating the coating solution, a conventionally known method such as a dip coating method, a spray coating method, a bead coating method, or a ring coating method can be adopted.
The film thickness of the charge generation layer 35 is 0.01 to 5 μm, preferably 0.05 to 2 μm.
[0121]
<Charge transport layer 37>
The charge transport layer 37 contains a charge transport material as a main component, and a binder resin (a binder resin for forming the charge transport layer 37) and additives can be added as appropriate.
As the charge transport material, a hole transport material, an electron transport material, or the like can be used.
[0122]
Electron transport materials include, for example, chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These substances may be used alone or as a mixture of two or more.
[0123]
Examples of the hole transport material include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, tria Electron-donating substances such as a reelmethane derivative, a 9-styrylanthracene derivative, a pyrazoline derivative, a divinylbenzene derivative, a hydrazone derivative, an indene derivative, a butadiene derivative, and a pyrene derivative, a bistilbene derivative, and an enamine derivative are preferably used. Moreover, well-known materials other than these can also be employ | adopted. These substances may be used alone or as a mixture of two or more.
[0124]
Examples of the binder resin for forming the charge transport layer 37 include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. Examples thereof include a polymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, and ethyl cellulose resin. These resins may be used alone or in combination of two or more.
[0125]
As the charge transport layer 37, a polymer charge transport material having a function as a binder resin for forming the charge transport layer 37 and a function as a charge transport material is also preferably used. The charge transport layer 37 containing the polymer charge transport material is excellent in wear resistance, and a high-quality image can be obtained. Note that a binder resin for forming the charge transport layer 37 and the low molecular charge transport material may be mixed and used.
A known material can be used as the polymer charge transport material, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. In particular, polymer charge transport materials represented by the following structural formulas (I) to (X) are preferably used.
[0126]
[Chemical 3]

[0127]
In the general formula (I), R ₁ , R ₂ , R _Three Each represents a substituted or unsubstituted alkyl group or halogen atom which may be the same or different; R _Four Represents a hydrogen atom or a substituted or unsubstituted alkyl group; R _Five , R ₆ Each represents a substituted or unsubstituted aryl group, which may be the same or different; o, p, q represent an integer of 0 to 4; k, j represent a composition (molar fraction), 0 .Ltoreq.k.ltoreq.1, 0.ltoreq.j.ltoreq.0.9; n represents the number of repeating units and is an integer of 5 to 5000; X is an aliphatic divalent group or a cyclic aliphatic divalent group. Represents a group or a divalent group represented by the general formula (1).
[0128]
In the general formula (1), R ₁₀₁ , R ₁₀₂ Each represents a substituted or unsubstituted alkyl group, aryl group or halogen atom which may be the same or different; l and m each represents an integer of 0 to 4; Y represents a single bond or a carbon atom having 1 to 12 carbon atoms. A linear, branched or cyclic alkylene group, -O-, -S-, -SO-, -SO ₂ —, —CO—, —CO—O—Z—O—CO— (Z represents an aliphatic divalent group) or a divalent group represented by the general formula (2).
[0129]
In the general formula (2), a is an integer of 1 to 20, b is an integer of 1 to 2000, R ₁₀₃ , R ₁₀₄ Represents a substituted or unsubstituted alkyl group or aryl group.
[0130]
[Formula 4]

[0131]
In the general formula (II), R ₇ , R ₈ Are the same or different substituted or unsubstituted aryl groups, Ar ₁ , Ar ₂ , Ar _Three Represents an arylene group which may be the same or different. X, k, j, and n are the same as those in the general formula (I).
[0132]
[Chemical formula 5]

[0133]
In the general formula (III), R ₉ , R _Ten Are the same or different substituted or unsubstituted aryl groups, Ar _Four , Ar _Five , Ar ₆ Represents an arylene group which may be the same or different. X, k, j, and n are the same as those in the general formula (I).
[0134]
[Chemical 6]

[0135]
In the general formula (IV), R ₁₁ , R ₁₂ Are the same or different substituted or unsubstituted aryl groups, Ar ₇ , Ar ₈ , Ar ₉ Represents the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j, and n are the same as those in the general formula (I).
[0136]
[Chemical 7]

[0137]
In the general formula (V), R ₁₃ , R ₁₄ Are the same or different substituted or unsubstituted aryl groups, Ar _Ten , Ar ₁₁ , Ar ₁₂ Are the same or different arylene groups, X ₁ , X ₂ Represents a substituted or unsubstituted ethylene group or a substituted or unsubstituted vinylene group which may be the same or different. X, k, j, and n are the same as in general formula (I).
[0138]
[Chemical 8]

[0139]
In the above general formula (VI), R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ Are the same or different substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , Ar ₁₆ Are the same or different arylene groups, Y ₁ , Y ₂ , Y _Three Represents the same or different single bond, substituted or unsubstituted alkylene group, substituted or unsubstituted cycloalkylene group, substituted or unsubstituted alkylene ether group, oxygen atom, sulfur atom or vinylene group. X, k, j, and n are the same as those in the general formula (I).
[0140]
[Chemical 9]

[0141]
In the general formula (VII), R ₁₉ , R ₂₀ Represents the same or different hydrogen atoms or substituted or unsubstituted aryl groups, and may form a ring with each other. Ar ₁₇ , Ar ₁₈ , Ar ₁₉ Represents an arylene group which may be the same or different. X, k, j, and n are the same as in general formula (I).
[0142]
Embedded image

[0143]
In the general formula (VIII), R _{twenty one} Is a substituted or unsubstituted aryl group, Ar ₂₀ , Ar _{twenty one} , Ar _{twenty two} , Ar _{twenty three} Represents an arylene group which may be the same or different. X, k, j, and n are the same as those in the general formula (I).
[0144]
Embedded image

[0145]
In the general formula (IX), R _{twenty two} , R _{twenty three} , R _{twenty four} , R _{twenty five} Are the same or different substituted or unsubstituted aryl groups, Ar _{twenty four} , Ar _{twenty five} , Ar ₂₆ , Ar ₂₇ , Ar ₂₈ Represents an arylene group which may be the same or different. X, k, j, and n are the same as those in the general formula (I).
[0146]
Embedded image

[0147]
In the general formula (X), R ₂₆ , R ₂₇ Are the same or different substituted or unsubstituted aryl groups, Ar ₂₉ , Ar ₃₀ , Ar ₃₁ Represents an arylene group which may be the same or different. X, k, j, and n are the same as those in the general formula (I).
[0148]
Hereinafter, some preferred specific examples (forms) of the polycarbonate containing a triarylamine structure in the main chain and / or side chain are shown below. If one or more of the compounds shown below are used, extremely excellent photosensitive properties (such as high image quality) can be obtained. However, it is not limited to these compounds.
[0149]
Embedded image

[0150]
Embedded image

[0151]
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[0152]
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[0153]
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[0154]
Embedded image

[0155]
Embedded image

[0156]
Embedded image

[0157]
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[0158]
Embedded image

[0159]
The polymer charge transport material is polymerized in the form of a homopolymer, a random copolymer, an alternating copolymer, or a block copolymer. Moreover, in order to implement | achieve the function as a binder resin, the film formation ability is required. In order to have a film forming ability, the molecular weight may be 10,000 to 500,000, preferably 50,000 to 400,000 in terms of polystyrene-equivalent molecular weight Mw as measured by GPC.
Such polymer charge transport materials include, for example, JP-A-8-269183, JP-A-9-71642, JP-A-9-104746, JP-A-9-272735, JP-A-11-29634. JP-A-9-235367, JP-A-9-87376, JP-A-9-110976, JP-A-9-268226, JP-A-9-221544, JP-A-9-227669, The substances disclosed in JP-A-9-157378, JP-A-9-302084, JP-A-9-302085, JP-A2000-26590, and the like can be suitably used.
[0160]
The charge transport layer 37 is formed by, for example, applying a coating liquid in which at least a charge transport material and a binder resin are dissolved or dispersed in an appropriate solvent or dispersion medium onto a coating layer such as the charge generation layer 35 and drying. Can be formed.
[0161]
The charge transport material is contained in an amount of 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin for forming the charge transport layer 37. However, when a polymer charge transport material is used, the charge transport material may be used alone or in combination with a binder resin or the like.
[0162]
As the solvent (solvent) and dispersion medium that can be used to form the charge transport layer 37, those that can be used to form the charge generation layer 35 can be used, but the charge transport material and the binder resin can be dissolved or dispersed well. The one to be used is appropriately selected and used. A plurality of solvents or dispersion media may be mixed and used.
[0163]
The charge transport layer 37 may be added with a leveling agent or a plasticizer as necessary.
Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. The leveling agent is preferably added in an amount exceeding 0 part by weight and not more than 1 part by weight based on 100 parts by weight of the binder resin.
A known plasticizer such as dibutyl phthalate or dioctyl phthalate can be used as the plasticizer, and it is preferably added in the range of more than 0 parts by weight and 30 parts by weight or less with respect to 100 parts by weight of the binder resin.
[0164]
As a coating method, a known coating method such as a dip coating method, a spray coating method, a bead coating method, or a ring coating method can be adopted.
The thickness of the charge transport layer 37 is suitably about 5 to 50 μm. Further, it is preferably 10 to 30 [mu] m, in which good resolution is obtained, good image characteristics such as less background stains are obtained, and electric characteristics such as charging potential and sensitivity are good.
[0165]
<Single-layer type photosensitive layer 33>
The single-layer type photosensitive layer 33 is, for example, a coating in which the above-described charge generating substance, charge transporting substance, binder resin (binding resin for forming the photosensitive layer 33) or the like is dissolved or dispersed in an appropriate solvent or dispersion medium. It can be formed by coating and drying the working liquid on a conductive support or the like.
As the charge generation material and the charge transport material, the materials described in the multilayer type photosensitive layer 33 can be used. As the binder resin for forming the photosensitive layer 33, the binder resin for forming the charge transport layer 37 can be used, and the binder resin for forming the charge generation layer 35 may be appropriately mixed and used. Moreover, you may employ | adopt the said polymeric charge transport material as binder resin.
The amount of the charge generating material with respect to 100 parts by weight of the binder resin for forming the photosensitive layer 33 is preferably 5 to 40 parts by weight, and more preferably 10 to 30 parts by weight. The charge transport material is preferably used in the range of more than 0 part by weight and not more than 190 parts by weight, and more preferably in the range of 50 to 150 parts by weight with respect to the binder resin.
[0166]
The photosensitive layer 33 can be formed as follows. (1) A charge generating substance, a binder resin, and a charge transporting substance are dissolved or dispersed in a solvent or dispersion medium such as tetrahydrofuran, dioxane, dichloroethane, cyclohexanone, toluene, methyl ethyl ketone, and acetone to prepare a coating solution. (2) The coating liquid can be formed by coating on a coating layer such as the conductive support 31 using a dip coating method, a spray coating method, a bead coating method, a ring coating method, or the like.
If necessary, various additives such as a plasticizer, a leveling agent, an antioxidant, and a lubricant can be added.
The film thickness of the photosensitive layer 33 is suitably about 5 to 25 μm.
[0167]
<Protective layer 39>
The protective layer 39 is a layer for protecting the photosensitive layer 33, the charge transport layer 37, and the like, and contains at least a binder resin (a binder resin for forming the protective layer 39). Further, a filler material is preferably contained.
As the binder resin for forming the protective layer 39, the binder resin for forming the charge transport layer 37 can be used. One or a plurality of the filler materials described above can be adopted.
[0168]
The protective layer 39 may further contain a charge transport material. The protective layer 39 containing the charge transport material has advantages such that the residual potential can be lowered and sensitivity deterioration can be suppressed.
Further, the above-described polymer charge transport material is preferably employed as the charge transport material. The photoconductor in which the polymer charge transport material is contained in the protective layer 39 can have a very low probability of occurrence of an abnormal image. This is because the polymer charge transporting material is unlikely to be altered or decomposed by ozone or NOx, and is excellent in scratch resistance as compared with the mixed system of the charge transporting material and the binder resin. In other words, organic carbon residue that increases the probability of occurrence of abnormal images is not generated or is difficult to generate, and in order to facilitate the removal of charged products, it is difficult to make fine scratches on the surface of the photoconductor. Is obtained.
As the charge transport material and the polymer charge transport material used in the protective layer, one or a plurality of materials arbitrarily selected from the same or similar materials as those usable in the charge transport layer 37 can be used.
[0169]
The protective layer 39 can be formed by coating the binder resin for forming the protective layer 39 on the coating layer in the same manner as the charge transport layer 37. For example, known coating methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating and ring coating can be used. Among them, a spray coating method that can easily control the film thickness, maintain good dispersibility of the graft copolymer and filler, and improve the coating film quality of the obtained photoreceptor (protective layer 39) is preferably employed.
In addition, the protective layer 39 may be formed by a single coating, but if the protective layer 39 is formed by applying two or more times, the filler material can be dispersed almost uniformly in the protective layer 39. When the filler material is uniformly dispersed, the residual potential can be kept low, the resolution can be increased, and the wear resistance can be increased. Moreover, the quality of the coating film can be increased and the occurrence of coating film defects can be suppressed.
The thickness of the protective layer 39 is preferably 0.5 μm to 10 μm, and more preferably 2 μm to 6 μm.
[0170]
<Underlayer>
The undercoat layer can be provided between the conductive support 31 and the photosensitive layer 33.
The undercoat layer generally contains a resin as a main component. However, since the photosensitive layer 33 is applied, it is desirable that the undercoat layer be a resin having high solvent resistance with respect to an organic solvent, particularly a solvent for forming the photosensitive layer 33. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, Examples thereof include curable resins that form a three-dimensional network structure such as epoxy resins.
The undercoat layer may be added with fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide in order to prevent moire and reduce residual potential.
Further, the undercoat layer may contain a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like.
[0171]
The undercoat layer can be formed in the same manner as the photosensitive layer 33. Further, the same solvent may be employed for coating (dispersion medium).
Al ₂ O _Three A layer formed on the coating layer by an anodic oxidation method, organic matter such as polyparaxylylene (parylene) or SiO ₂ , SnO ₂ TiO ₂ , ITO, CeO ₂ It is good also considering the layer provided on the to-be-coated layer by the vacuum thin film preparation method as an undercoat layer.
In addition to these, known layer forming methods can be employed.
The thickness of the undercoat layer is preferably in the range of more than 0 μm and not more than 5 μm.
[0172]
<Intermediate layer>
An intermediate layer may be provided between the undercoat layer and the photosensitive layer 33 or between the photosensitive layer 33 and the protective layer 39.
The intermediate layer generally contains a binder resin (binder resin) as a main component. Examples of the resin that can be used include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol.
As the method for forming the intermediate layer, a known coating method as described above can be used.
The thickness of the intermediate layer is suitably 0.05-2 μm.
[0173]
<Matters common to each layer>
In addition, in order to improve environmental resistance, in particular, in order to prevent a decrease in sensitivity and an increase in residual potential, an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, a low molecular weight are formed on one or more layers of the photoreceptor. It is preferable to add a charge transporting material, a leveling agent and the like as appropriate.
[0174]
<Antioxidant>
Examples of the antioxidant include, but are not limited to, the following.
(A) Phenolic compounds
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl-3- (4′-hydroxy-3 ′, 5 '-Di-t-butylphenol), 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-t-) Butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- ( 2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, Tetrakis- [methylene-3 -(3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid ] Crycol ester, tocopherols, etc.
[0175]
(B) Paraphenylenediamines
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.
[0176]
(C) Hydroquinones
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.
[0177]
(D) Organic sulfur compounds
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.
[0178]
(E) Organophosphorus compounds
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
[0179]
<Plasticizer>
Examples of the plasticizer include, but are not limited to, the following.
(A) Phosphate ester plasticizer
Triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate and the like.
[0180]
(B) Phthalate ester plasticizer
Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, phthalic acid Diisodecyl, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, dioctyl fumarate, etc.
[0181]
(C) Aromatic carboxylic ester plasticizer
Trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate, and the like.
[0182]
(D) Aliphatic dibasic acid ester plasticizer
Dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, n-octyl-n-decyl adipate, diisodecyl adipate, dicapryl adipate, diazeline 2-ethylhexyl, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2-ethoxyethyl sebacate, dioctyl succinate, diisodecyl succinate, Dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate and the like.
[0183]
(E) Fatty acid ester derivatives
Butyl oleate, glycerol monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin and the like.
[0184]
(F) Oxyester plasticizer
Methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate and the like.
[0185]
(G) Epoxy plasticizer
Epoxidized soybean oil, epoxidized linseed oil, butyl epoxy stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, didecyl epoxy hexahydrophthalate and the like.
[0186]
(H) Dihydric alcohol ester plasticizer
Diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyrate, etc.
[0187]
(I) Chlorine-containing plasticizer
Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxychlorinated fatty acid methyl, etc.
[0188]
(J) Polyester plasticizer
Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester, etc.
[0189]
(K) Sulfonic acid derivative
p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide, p-toluenesulfone-N-cyclohexylamide and the like.
[0190]
(L) Citric acid derivative
Triethyl citrate, triethyl citrate citrate, tributyl citrate, tributyl acetyl citrate, tri-2-ethylhexyl acetyl citrate, acetyl citrate-n-octyldecyl and the like.
[0191]
(M) Other
Terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietate and the like.
[0192]
<Lubricant>
Examples of the lubricant include, but are not limited to, the following.
(A) Hydrocarbon compounds
Liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene, etc.
[0193]
(B) Fatty acid compounds
Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, etc.
[0194]
(C) Fatty acid amide compounds
Stearylamide, palmitylamide, oleinamide, methylenebisstearamide, ethylenebisstearamide, etc.
[0195]
(D) Ester compound
Lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, fatty acid polyglycol esters, and the like.
[0196]
(E) Alcohol compounds
Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol, etc.
[0197]
(F) Metal soap
Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate, etc.
[0198]
(G) Natural wax
Carnauba wax, candelilla wax, beeswax, whale wax, ibotarou, montanro, etc.
[0199]
(H) Other
Silicone compounds, fluorine compounds, etc.
[0200]
<Ultraviolet absorber>
Examples of the ultraviolet absorber include, but are not limited to, the following.
(A) Benzophenone series
2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, and the like.
[0201]
(B) Salsylate type
Phenyl salsylate, 2,4 di-t-butylphenyl 3,5-di-t-butyl 4-hydroxybenzoate, and the like.
[0202]
(C) Benzotriazole type
(2′-hydroxyphenyl) benzotriazole, (2′-hydroxy5′-methylphenyl) benzotriazole, (2′-hydroxy5′-methylphenyl) benzotriazole, (2′-hydroxy3′-tertiarybutyl 5) '-Methylphenyl) 5-chlorobenzotriazole
[0203]
(D) Cyanoacrylate type
Ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy 3 (paramethoxy) acrylate, and the like.
[0204]
(E) Quencher (metal complex)
Nickel (2,2 ′ thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyldithiocarbamate, nickel dibutyldithiocarbamate, cobalt dicyclohexyldithiophosphate and the like.
[0205]
(F) HALS (hindered amine)
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy- 2,2,6,6-tetramethylpiperidine and the like.
[0206]
<Configuration other than photoconductor, electrophotographic method>
Next, the configuration other than the photoreceptor of the electrophotographic apparatus and the electrophotographic method will be described in detail with reference to the drawings.
The electrophotographic apparatus forms at least a toner image by charging, exposing, and developing the photosensitive member (electrophotographic photosensitive member) as described above, and transferring and fixing the toner image onto an image holding member (transfer paper). Let Then, the surface of the photoreceptor is cleaned.
However, this process is an example of an image forming process in the electrophotographic apparatus according to the present invention, and in some cases, some steps may be omitted or another step may be provided. Good.
[0207]
FIG. 6 is a schematic view showing a configuration example of the electrophotographic apparatus.
In FIG. 6, the above-described photoreceptor is adopted as the photoreceptor 1. The photosensitive member 1 has a drum shape, but may have a sheet shape, an endless belt shape, or the like.
[0208]
As the charging member 3, a charging roller device is mainly used, and the photosensitive member 1 and the charging member are arranged close to each other in a non-contact manner in the image forming region. As described above, in order to dispose the charging member close to the photoreceptor 1, a gap may be provided in the non-image forming region of the photoreceptor 1. For example, the gap material may be provided on the charging member, provided on the photosensitive member 1, or provided on a flange portion set at both ends of the photosensitive member. However, any configuration may be adopted as long as the photosensitive member 1 and the charging member are disposed close to each other.
[0209]
FIG. 7 shows an example in which a gap member is provided on the charging member. In this example, the gap material is preferably an insulating material with high wear resistance.
The gap material may have any form such as a tape, a seal, or a tube.
The thickness of the gap is preferably 10 to 200 μm, more preferably 20 to 100 μm, and further preferably 40 to 80 μm. When the thickness of the gap is within this range, the charging member and the photosensitive member 1 are hardly in contact with each other, so that the image quality is hardly deteriorated. In addition, charging unevenness is very rarely generated without lowering the charging stability, and it is not necessary to increase the applied voltage for maintaining the required charging level. Therefore, since the generation amount of the charged product can be reduced, the occurrence probability of the abnormal image can be extremely reduced.
[0210]
Further, the charging member may be charged with the AC charge by superimposing the AC component on the DC component. By superimposing the AC component in this way, charging unevenness can be reduced. Thereby, image density unevenness and contrast reduction can be prevented.
[0211]
The image exposure unit 5 forms an electrostatic latent image on the charged photoreceptor 1.
As the light source, for example, a light emitting material such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), or electroluminescence (EL) may be appropriately selected and used. In addition, various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter may be used to irradiate only light in a desired wavelength range.
[0212]
The developing unit 6 visualizes the electrostatic latent image formed on the photoreceptor 1.
Development methods include a one-component development method using dry toner, a two-component development method, and a wet development method using wet toner. When the photosensitive member is positively charged and image exposure is performed, a positive electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative polarity toner (detection fine particles), and a negative image can be obtained by development with positive polarity toner. The sign may be reversed.
[0213]
The transfer charger 10 transfers the toner image visualized on the photoreceptor 1 onto the transfer body. In order to perform better transfer, the pre-transfer charger 7 may be used. As a transfer method, an electrostatic transfer method using a transfer charger or a bias roller, a mechanical transfer method such as an adhesive transfer method or a pressure transfer method, or a magnetic transfer method can be adopted. The electrostatic transfer method may be performed using a charging unit.
[0214]
The separation charger 11 and the separation claw 12 are means for separating the transfer member from the photosensitive member. In addition, as the separating means, electrostatic adsorption induction separating means, side end belt separating means, tip grip conveying means, curvature separating means, etc. can be used. The separation charger may use charging means.
[0215]
The fur brush 14 and the cleaning blade 15 clean the toner remaining on the photoconductor after transfer. Further, a pre-cleaning charger 13 may be used in order to perform cleaning more efficiently.
In addition, a web method, a magnet brush method, or the like may be employed as a cleaning method. Any one or a plurality of cleaning methods may be employed.
[0216]
The neutralizing means removes the latent image on the photoreceptor 1. For example, the neutralization lamp 2 and the neutralization charger are used as the neutralization unit, and may be realized by using the exposure light source and the charging unit, respectively.
[0217]
Known document reading means, paper feeding means, fixing means, paper discharge means and the like can be employed.
Also, other configurations / processes than those shown in FIG. 6 can be adopted. For example, in the configuration example of FIG. 6, the light irradiation process to the photoconductor is realized by image exposure, pre-cleaning exposure, and static elimination exposure, but known light irradiation such as pre-exposure of transfer and pre-exposure of image exposure. The photosensitive member may be irradiated with light by a process.
[0218]
The image forming means as described above may be fixedly incorporated in the electrophotographic apparatus, but one or more of them may be provided in a process cartridge that can be attached to and detached from the electrophotographic apparatus, and the process cartridge is an electrophotographic apparatus. You may make it incorporate in an electrophotographic apparatus by installing in a photographic apparatus.
FIG. 8 shows one configuration example of such a process cartridge for an electrophotographic apparatus. The process cartridge includes a photosensitive member (photosensitive drum 101), and in addition, an apparatus (at least one of a charging unit 102, a developing unit, a transfer unit 106, a cleaning unit (such as a cleaning blade 107), and a discharging unit). Parts).
[0219]
(Example)
Hereinafter, the present invention will be described by way of examples. However, the present invention is not construed as being limited to the following examples. Hereinafter, “parts” means parts by weight.
[0220]
Example 1
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied / dried on a φ30 mm aluminum drum (conductive support 31) by a dip coating method. An undercoat layer having a thickness of about 3.5 μm, a charge generation layer 35 having a thickness of about 0.2 μm, and a charge transport layer 37 having a thickness of about 25 μm were formed to produce a photoreceptor.
[0221]
[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts
(Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Melamine resin 4 parts
(Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide 40 parts
・ Methyl ethyl ketone 50 parts
[0222]
[Coating liquid for charge generation layer]
-2.5 parts of bisazo pigment represented by the following general formula (4)
・ Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 part
・ 200 parts of cyclohexanone
・ Methyl ethyl ketone 80 parts
[0223]
[Coating liquid for charge transport layer]

[0224]
Embedded image

[0225]
(Example 2)
A photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution in Example 1 was changed to the following charge transport layer coating solution.
[Coating liquid for charge transport layer]

[0226]
Embedded image

[0227]
Example 3
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution was changed to the following charge transport layer coating solution and the charge transport layer 37 was formed by the ring coating method. .
[Coating liquid for charge transport layer]

[0228]
Embedded image

[0229]
Example 4
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution was changed to the following charge transport layer coating solution and the charge transport layer 37 was formed by the ring coating method. .
[Coating liquid for charge transport layer]

[0230]
Embedded image

[0231]
(Example 5)
A photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution in Example 1 was changed to the following charge transport layer coating solution.
[Coating liquid for charge transport layer]

[0232]
Embedded image

[0233]
(Example 6)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution was changed to the following charge transport layer coating solution and the charge transport layer 37 was formed by the ring coating method. .
[Coating liquid for charge transport layer]

[0234]
Embedded image

[0235]
(Example 7)
A photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution in Example 1 was changed to the following charge transport layer coating solution.
[Coating liquid for charge transport layer]

[0236]
Embedded image

[0237]
(Example 8)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution was changed to the following charge transport layer coating solution and the charge transport layer 37 was formed by the ring coating method. .
[Coating liquid for charge transport layer]

[0238]
Embedded image

[0239]
Example 9
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied / dried onto a 30 mm diameter aluminum drum (conductive support 31) by a ring coating method. Then, an undercoat layer having a thickness of about 3.5 μm, a charge generation layer 35 having a thickness of about 0.2 μm, and a charge transport layer 37 having a thickness of about 25 μm were formed to produce a photoreceptor.
[0240]
[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts
(Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Melamine resin 4 parts
(Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Titanium oxide 40 parts
・ Methyl ethyl ketone 50 parts
[0241]
[Coating liquid for charge generation layer]
8 parts of titanyl phthalocyanine having the XD spectrum shown in FIG.
・ 0.5 parts of polyvinyl butyral (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.)
・ Methyl ethyl ketone 400 parts
[0242]
[Coating liquid for charge transport layer]

[0243]
Embedded image

[0244]
(Example 10)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied / dried on a φ30 mm aluminum drum (conductive support 31) by a dip coating method. Thus, an undercoat layer having a thickness of about 3.5 μm, a charge generation layer 35 having a thickness of about 0.2 μm, and a charge transport layer 37 having a thickness of about 20 μm were formed. On the charge transport layer 37, a protective layer coating solution having the following composition was applied / dried by a ring coating method to form a protective layer 39 having a thickness of about 5 μm, thereby preparing a photoreceptor.
[0245]
[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts
(Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Melamine resin 4 parts
(Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Titanium oxide 40 parts
・ Methyl ethyl ketone 50 parts
[0246]
[Coating liquid for charge generation layer]
-2.5 parts of bisazo pigment represented by the following general formula (4)
・ Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 part
・ 200 parts of cyclohexanone
・ Methyl ethyl ketone 80 parts
[0247]
[Coating liquid for charge transport layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ 100 parts of tetrahydrofuran
1 part of 1% silicone oil tetrahydrofuran solution
(Silicone oil: KF50-100CS, manufactured by Shin-Etsu Chemical)
・ Antioxidant represented by the following general formula (6) (manufactured by Sumitomo Chemical Co., Ltd.) 0.15 parts
[0248]
[Coating liquid for protective layer]

[0249]
Embedded image

[0250]
(Example 11)
A photoconductor was prepared in the same manner as in Example 10 except that the protective layer coating solution was changed to the following protective layer coating solution in Example 10.
[Coating liquid for protective layer]

[0251]
Embedded image

[0252]
(Example 12)
A photoconductor was prepared in the same manner as in Example 10 except that the protective layer coating solution was changed to the following protective layer coating solution in Example 10.
[Coating liquid for protective layer]

[0253]
Embedded image

[0254]
(Example 13)
A photoconductor was prepared in the same manner as in Example 10 except that the protective layer coating solution was changed to the following protective layer coating solution and the protective layer 39 was formed by spray coating.
[Coating liquid for protective layer]

[0255]
Embedded image

[0256]
(Example 14)
A photoconductor was prepared in the same manner as in Example 10 except that the protective layer coating solution was changed to the following protective layer coating solution in Example 10.
[Coating liquid for protective layer]

[0257]
Embedded image

[0258]
(Example 15)
A photoconductor was prepared in the same manner as in Example 10 except that the protective layer coating solution was changed to the following protective layer coating solution and the protective layer 39 was formed by spray coating.
[Coating liquid for protective layer]

[0259]
Embedded image

[0260]
(Example 16)
A photoconductor was prepared in the same manner as in Example 10 except that the protective layer coating solution was changed to the following protective layer coating solution in Example 10.
[Coating liquid for protective layer]

[0261]
Embedded image

[0262]
(Example 17)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied / dried on a φ30 mm aluminum drum (conductive support 31) by a dip coating method. Thus, an undercoat layer having a thickness of about 3.5 μm, a charge generation layer 35 having a thickness of about 0.2 μm, and a charge transport layer 37 having a thickness of about 20 μm were formed. On the charge transport layer 37, a protective layer coating solution having the following composition was applied / dried by a ring coating method to form a protective layer 39 having a thickness of about 5 μm, whereby the electrophotographic photoreceptor 17 was produced.
[0263]
[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts
(Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Melamine resin 4 parts
(Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide 40 parts
・ Methyl ethyl ketone 50 parts
[0264]
[Coating liquid for charge generation layer]

[0265]
[Coating liquid for charge transport layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 8 parts of a low molecular charge transport material represented by the following general formula (5)
・ 100 parts of tetrahydrofuran
1 part of 1% silicone oil tetrahydrofuran solution
(Silicone oil: KF50-100CS, manufactured by Shin-Etsu Chemical)
[0266]
[Coating liquid for protective layer]

[0267]
Embedded image

[0268]
(Example 18)
In Example 17, a photoconductor was prepared in the same manner as in Example 17 except that the protective layer coating solution was changed to the following protective layer coating solution and the protective layer 39 was formed by spray coating.
[Coating liquid for protective layer]

[0269]
Embedded image

[0270]
(Example 19)
In Example 17, a photoconductor was prepared in the same manner as in Example 17 except that the protective layer coating solution was changed to the following protective layer coating solution and the protective layer 39 was formed by spray coating.
[Coating liquid for protective layer]

[0271]
Embedded image

[0272]
(Comparative Example 1)
A photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution in Example 1 was changed to the following charge transport layer coating solution.
[Coating liquid for charge transport layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ 100 parts of tetrahydrofuran
1 part of 1% silicone oil tetrahydrofuran solution
(Silicone oil: KF50-100CS, manufactured by Shin-Etsu Chemical)
[0273]
Embedded image

[0274]
(Comparative Example 2)
A photoreceptor was prepared in the same manner as in Comparative Example 1 except that the charge transport layer coating solution was changed to the following charge transport layer coating solution in Comparative Example 1.
[Coating liquid for charge transport layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ 100 parts of tetrahydrofuran
1 part of 1% silicone oil tetrahydrofuran solution
(Silicone oil: KF50-100CS, manufactured by Shin-Etsu Chemical)
・ Α alumina 2 parts
(Sumicorundum AA-03, average primary particle size: 0.3 μm, pH 8-9, manufactured by Sumitomo Chemical)
・ 0.05 parts of polycarboxylic acid compound
(BYK-P104, solid content about 50%, manufactured by BYK Chemie)
・ Antioxidant represented by the following general formula (9) (manufactured by Sumitomo Chemical Co., Ltd.) 0.1 part
[0275]
Embedded image

[0276]
(Comparative Example 3)
A photoreceptor was prepared in the same manner as in Comparative Example 1 except that the charge transport layer coating solution was changed to the following charge transport layer coating solution in Comparative Example 1.
[Coating liquid for charge transport layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ 100 parts of tetrahydrofuran
1 part of 1% silicone oil tetrahydrofuran solution
(Silicone oil: KF50-100CS, manufactured by Shin-Etsu Chemical)
・ Titanium oxide 3.5 parts
(CR-EL, average primary particle size: 0.3 μm, pH 6-7, manufactured by Ishihara Sangyo)
・ Polycarboxylic acid compound 0.10 parts
(BYK-P104, solid content about 50%, manufactured by BYK Chemie)
-0.15 part of antioxidant represented by the following general formula (8)
(Sanol LS-2626, Sankyo)
[0277]
Embedded image

[0278]
(Comparative Example 4)
A photoconductor was prepared in the same manner as in Example 10 except that the protective layer coating solution was changed to the following protective layer coating solution in Example 10.
[Coating liquid for protective layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ 160 parts of tetrahydrofuran
[0279]
Embedded image

[0280]
(Comparative Example 5)
In Comparative Example 4, a photoconductor was prepared in the same manner as in Comparative Example 4 except that the protective layer coating solution was changed to the following protective layer coating solution and the protective layer 39 was formed by spray coating.
[Coating liquid for protective layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ Α alumina 3 parts
(Sumicorundum AA-03, average primary particle size: 0.3 μm, pH 8-9, manufactured by Sumitomo Chemical)
・ Polycarboxylic acid compound 0.06 parts
(BYK-P104, solid content about 50%, manufactured by BYK Chemie)
・ 350 parts of tetrahydrofuran
・ Cyclohexanone 100 parts
-0.15 part of antioxidant represented by the following general formula (8)
(Sanol LS-2626, Sankyo)
[0281]
Embedded image

[0282]
(Comparative Example 6)
In Comparative Example 4, a photoconductor was prepared in the same manner as in Comparative Example 4 except that the protective layer coating solution was changed to the following protective layer coating solution and the protective layer 39 was formed by spray coating.
[Coating liquid for protective layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ Α alumina 5 parts
(Sumicorundum AA-03, average primary particle size: 0.3 μm, pH 8-9, manufactured by Sumitomo Chemical)
・ Polycarboxylic acid compound 0.10 parts
(BYK-P104, solid content about 50%, manufactured by BYK Chemie)
・ 350 parts of tetrahydrofuran
・ Cyclohexanone 100 parts
-0.15 part of antioxidant represented by the following general formula (8)
(Sanol LS-2626, Sankyo)
[0283]
Embedded image

[0284]
(Comparative Example 7)
A photoconductor was prepared in the same manner as in Comparative Example 4 except that the protective layer coating solution was changed to the following protective layer coating solution in Comparative Example 4.
[Coating liquid for protective layer]
-18 parts of a polymer charge transport material represented by the following general formula (11)
・ Α alumina 3 parts
(Sumicorundum AA-03, average primary particle size: 0.3 μm, pH 8-9, manufactured by Sumitomo Chemical)
・ 0.05 parts of polycarboxylic acid compound
(BYK-P104, solid content about 50%, manufactured by BYK Chemie)
・ 350 parts of tetrahydrofuran
・ Cyclohexanone 100 parts
-0.15 part of antioxidant represented by the following general formula (8)
(Sanol LS-2626, Sankyo)
[0285]
Embedded image

[0286]
(Comparative Example 8)
A photoconductor was prepared in the same manner as in Comparative Example 4 except that the protective layer coating solution was changed to the following protective layer coating solution in Comparative Example 4.
[Coating liquid for protective layer]
-18 parts of a polymer charge transport material represented by the following general formula (11)
・ Α alumina 5 parts
(Sumicorundum AA-03, average primary particle size: 0.3 μm, pH 8-9, manufactured by Sumitomo Chemical)
・ Polycarboxylic acid compound 0.10 parts
(BYK-P104, solid content about 50%, manufactured by BYK Chemie)
・ 350 parts of tetrahydrofuran
・ Cyclohexanone 100 parts
-0.15 part of antioxidant represented by the following general formula (8)
(Sanol LS-2626, Sankyo)
[0287]
Embedded image

[0288]
(Comparative Example 9)
In Comparative Example 4, a photoconductor was prepared in the same manner as in Comparative Example 4 except that the protective layer coating solution was changed to the following protective layer coating solution and the protective layer 39 was formed by spray coating.
[Coating liquid for protective layer]
・ Bisphenol Z polycarbonate 10 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
・ 7 parts of a low molecular charge transport material represented by the following general formula (5)
・ Α alumina 3 parts
(Sumicorundum AA-03, average primary particle size: 0.3 μm, pH 8-9, manufactured by Sumitomo Chemical)
・ Polycarboxylic acid compound 0.10 parts
(BYK-P104, solid content about 50%, manufactured by BYK Chemie)
・ Spherical silicone fine particles 2 parts
(Average primary particle size of about 0.5 μm, “Tospearl 105” manufactured by Toshiba Silicone)
・ 350 parts of tetrahydrofuran
・ Cyclohexanone 100 parts
-0.15 part of antioxidant represented by the following general formula (8)
(Sanol LS-2626, Sankyo)
[0289]
Embedded image

[0290]
The photoconductor produced as described above was mounted on an electrophotographic process cartridge (without exposure means before cleaning). This process cartridge was set in a remodeling machine manufactured by Ricoh Co., Ltd., trade name imagioMF2200, in which the charging means was a charging roller and the image exposure light source was a semiconductor laser having a wavelength of 655 nm. Further, a Teflon (registered trademark) tape having a thickness of 50 μm was wound and fixed at both ends (non-image forming area) of the charging roller, and the charging member was disposed in proximity to the photoreceptor.
[0291]
And the following evaluation was performed.
(1) Image evaluation in an initial state (after one image formation) under an environment of 25 ° C. and 50% RH.
(2) Image evaluation in an initial state in an environment of 30 ° C. and 90% RH.
(3) Image evaluation after printing 60,000 sheets in an environment of 25 ° C. and 50% RH, and measurement of the wear amount of the photoreceptor.
The image formation was performed by applying AC (1 kHz, 1.8 kV (peak to peak)) + DC (−750 V) to the charging roller. The amount of wear was measured as a difference from the initial state.
(4) Image evaluation after printing 60,000 sheets in the same manner as in (3) under the environment of 30 ° C. and 90% RH, and measurement of the wear amount of the photoreceptor.
The image evaluation was performed visually according to the following criteria.
A: Good level with no image degradation
○: Level at which image quality degradation is observed but there is no problem
Δ: Level at which image quality can clearly be confirmed
×: Level at which image degradation is significant and image discrimination is difficult
The results are shown in Table 1.
[0292]
[Table 1]

[0293]
As can be seen from Table 1, a good image was obtained in the initial state even when a charging roller with a relatively small generation amount of ozone and NOx was used in the conventional photoconductor, but it was repeated in a high temperature and high humidity environment. Deterioration in image quality was confirmed when used.
Further, it was confirmed that the photoconductor not containing a filler had a large amount of film thickness variation due to wear, and the occurrence of background contamination.
Image blur occurred on the photoreceptor containing the filler. It was confirmed that abnormal images are more likely to occur as the filler content increases.
[0294]
On the other hand, it was confirmed that the photoreceptor containing the above graft copolymer in the outermost surface layer had a reduced amount of wear compared to the conventional case when it did not contain a filler. In addition, the generation of background stains was not observed even after printing 60,000 sheets.
It has been found that the photoreceptor containing the filler can form a good image even in the initial state or after printing 60,000 sheets. It was also found that good images can be obtained even when the amount of filler added is increased.
[0295]
The preferred embodiment of the present invention has been described above. However, the above-described embodiment is an example for explaining the present invention, and the scope of the present invention is not limited to this embodiment. Those skilled in the art can implement the present invention in various other forms in which various modifications, improvements, modifications, simplifications, and the like are added to the above-described embodiments without departing from the gist of the present invention.
[0296]
【The invention's effect】
As is apparent from the above description, according to the present invention, the outermost surface layer of the photoreceptor contains a graft copolymer having a core / shell structure containing a polyorganosiloxane component, and the charging member is incorporated in the photoreceptor. In contrast to this, the amount of ozone and NOx gas generated is extremely small, and the surface energy and friction coefficient of the photoreceptor are extremely low, so that these characteristics can be stably maintained over a long period of time. Thereby, for example, the occurrence probability of an abnormal image can be made extremely low. That is, it has become possible to both suppress the generation of ozone and the like and to prevent the charged product from adhering to the photoreceptor, and to maintain this effect.
[0297]
In addition, even with a photoreceptor whose outermost surface layer contains a filler and has improved wear resistance, the probability of occurrence of an abnormal image can be extremely lowered over a long period of time. This is the effect obtained because the sustainability of the effect of reducing the surface energy can be remarkably increased and the charging member is not in contact with the photosensitive member. In other words, as in the prior art, the problem that the probability of occurrence of an abnormal image is extremely high particularly when the charged product adheres to the photosensitive member, particularly under high temperature and high humidity has been solved. That is, high durability and high image quality of the electrophotographic apparatus were realized.
Further, even when the outermost surface layer does not contain a filler, the wear resistance of the photoreceptor can be increased.
[0298]
Also, the cleaning property and transfer efficiency of the photoconductor can be improved, the occurrence of abnormal images due to filming and foreign matter adhesion can be suppressed, discharge breakdown can be suppressed, wear resistance can be improved, and uneven wear can be suppressed. It is now possible to provide an electrophotographic apparatus having high durability and high image quality. In addition, such an effect can be sustained even after repeated use.
[0299]
In addition, using a basic metal oxide for the filler, applying a surface treatment to the filler, adding a polymer charge transport material to the outermost surface layer of the photoreceptor, adding an antioxidant, etc. It has become possible to further reduce the image generation probability (additional margin for the influence of abnormal image / image blur).
[0300]
Further, if the outermost surface layer contains a carboxylic acid compound, it is possible to improve the stability of the electrostatic characteristics of the photoreceptor, and extremely good high durability and high image quality can be realized.
[0301]
As described above, since the electrophotographic apparatus according to the present invention can suppress the occurrence of abnormal images without requiring a dehumidifying device such as a drum heater, it is possible to reduce the size and power consumption.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of the layer structure of an electrophotographic photoreceptor according to the present invention.
FIG. 2 is a cross-sectional view showing another layer configuration example of the electrophotographic photosensitive member according to the present invention.
FIG. 3 is a cross-sectional view showing another layer configuration example of the electrophotographic photosensitive member according to the present invention.
FIG. 4 is a cross-sectional view showing another layer configuration example of the electrophotographic photosensitive member according to the present invention.
FIG. 5 is a cross-sectional view showing another layer configuration example of the electrophotographic photosensitive member according to the present invention.
FIG. 6 is a schematic view showing an electrophotographic process cartridge and an electrophotographic apparatus according to the present invention.
FIG. 7 is a diagram for explaining the positional relationship between a charging unit and an electrophotographic photosensitive member according to the present invention.
FIG. 8 is a schematic view showing a configuration example of a process cartridge according to the present invention.
FIG. 9 shows an XD spectrum of oxytitanium phthalocyanine.
[Explanation of symbols]
1 Photoconductor
2 Static elimination lamp
3 Charging roller
5 Image exposure section
6 Development unit
7 Charger before transfer
8 Registration roller
9 Transfer paper
10 Transcription charger
11 Separate charger
12 Separating nails
13 Charger before cleaning
14 Fur brush
15 Cleaning brush
31 Conductive support
33 Photosensitive layer
35 Charge generation layer
37 Charge transport layer
39 Protective layer
101 Photosensitive drum
102 Charging device
103 Exposure apparatus
104 Developing device
105 Transcript
106 Transfer device
107 Cleaning blade

Claims (20)

In an electrophotographic apparatus provided with at least a charging means, an exposure means, a developing means, and a transfer means around an electrophotographic photosensitive member,
The electrophotographic photoreceptor contains a graft copolymer having a core / shell structure containing a polyorganosiloxane component on the outermost surface layer,
The electrophotographic apparatus according to claim 1, wherein the charging unit is disposed in proximity to the electrophotographic photosensitive member. The graft copolymer is a graft composite rubber copolymer obtained by graft-polymerizing a vinyl monomer to a composite rubber having a polyorganosiloxane and a polyalkyl acrylate rubber and / or a polyalkyl methacrylate rubber. The electrophotographic apparatus according to claim 1. 3. The electrophotographic apparatus according to claim 1, wherein the graft copolymer contains a polyorganosiloxane component more than other components. 4. The electrophotographic apparatus according to claim 1, wherein the graft copolymer has an average particle diameter in a range of 0.05 μm to 5.0 μm. 5. The electrophotographic apparatus according to claim 1, wherein the graft copolymer is contained in an amount of 1 to 40% by weight of the total solid content in the outermost surface layer. The electrophotographic apparatus according to claim 1, wherein the outermost surface layer contains a kneaded material obtained by melt-kneading the graft copolymer and a binder resin. The electrophotographic apparatus according to claim 1, wherein the charging unit is a charging roller. The electrophotographic apparatus according to claim 7, wherein the charging roller charges the electrophotographic photosensitive member with a voltage in which an AC component is superimposed on a DC component. 9. The electrophotographic apparatus according to claim 7, wherein a gap between the charging roller and the image forming area of the electrophotographic photosensitive member is more than 0 μm and not more than 200 μm. The electrophotographic apparatus according to claim 1, wherein the outermost surface layer contains a filler. The electrophotographic apparatus according to claim 10, wherein the filler is a metal oxide. The electrophotographic apparatus according to claim 11, wherein the metal oxide has a pH at an isoelectric point of 5 or more. The electrophotographic apparatus according to claim 11, wherein the metal oxide is surface-treated. 14. The electrophotographic apparatus according to claim 10, wherein the filler has an average primary particle size in the range of 0.01 μm to 0.9 μm. The electrophotographic apparatus according to claim 1, wherein the outermost surface layer contains a carboxylic acid compound. The electrophotographic apparatus according to claim 15, wherein the carboxylic acid compound is a polycarboxylic acid compound. The electrophotographic apparatus according to claim 1, wherein the outermost surface layer contains a polymer charge transport material. The electrophotographic apparatus according to any one of claims 1 to 17, wherein the outermost surface layer contains an antioxidant. The electrophotographic apparatus according to claim 18, wherein the antioxidant has a hindered amine structure and a hindered phenol structure. 20. The electrophotographic apparatus according to claim 1, wherein at least the charging unit and the electrophotographic photosensitive member are provided in a process cartridge that is detachable from the electrophotographic apparatus main body.

Images