JP3848153B2 - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Description

【００３２】
式中、Ｒ₁、Ｒ₂及びＲ₃はそれぞれ炭素数１〜８の枝分かれしてもよい２価の炭化水素基を示し、α、β及びγはそれぞれ置換基としてハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基又は置換基を有してもよい複素環基を１つ以上有してもよいベンゼン環を示し、ａ、ｂ及びｄは０又は１であり、ｍ及びｎは０又は１である。
【００３３】
【化５】

【００３４】
式中、Ｒ₄及びＲ₅はそれぞれ炭素数１〜８の枝分かれしてもよい２価の炭化水素基を示し、δ及びεはそれぞれ置換基としてハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基又は置換基を有してもよい複素環基を１つ以上有してもよいベンゼン環を示し、ｅ及びｆは０又は１である。ｐは０又は１である。Ｚ₁及びＺ₂はそれぞれハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基又は置換基を有してもよい複素環基を示し、共同で環をなしてもよい。
【００３５】
【化６】

【００３６】
式中、Ｒ₆、Ｒ₇、Ｒ₈及びＲ₉はそれぞれ炭素数１〜８の枝分かれしてもよい２価の炭化水素基を示し、ζ、η、θ及びιはそれぞれ置換基としてハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基又は置換基を有してもよい複素環基を１つ以上有してもよいベンゼン環を示し、ｇ、ｈ、ｊ及びｋは０又は１であり、ｑ、ｒ及びｓは０又は１である。Ｚ₃及びＺ₄はそれぞれハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基又は置換基を有してもよい複素環基を示し、共同で環をなしてもよい。
【００３７】
上記式（１）〜（３）における置換基等の構造について以下に詳しく説明する。
【００３８】
式中、Ｒ₁〜Ｒ₉はそれぞれ炭素数１〜８の枝分かれしてもよい、メチレン基、エチレン基、プロピレン基及びブチレン等の２価の炭化水素基を示す。
【００３９】
式中、α、β、γ、δ、ε、ζ、η、θ及びιが示すベンゼン環が有してもよい置換基としては、フッ素、塩素、臭素及びヨウ素等のハロゲン原子、置換基を有してもよいメチル基、エチル基、プロピル基及びブチル基等のアルキル基、置換基を有してもよいメトキシ基、エトキシ基、プロポキシ基及びブトキシ基等のアルコキシ基、置換基を有してもよいフェニル基、ナフチル基、アンスリル基及びピレニル基等のアリール基、又は置換基を有してもよいピリジル基、チエニル基、フリル基及びキノリル基等の複素環基を示す。
【００４０】
式中、Ｚ₁〜Ｚ₄はフッ素、塩素、臭素及びヨウ素等のハロゲン原子、置換基を有してもよいメチル基、エチル基、プロピル基及びブチル基等のアルキル基、置換基を有してもよいメトキシ基、エトキシ基、プロポキシ基及びブトキシ基等のアルコキシ基、置換基を有してもよいフェニル基、ナフチル基、アンスリル基及びピレニル基等のアリール基、又は置換基を有してもよいピリジル基、チエニル基、フリル基及びキノリル基等の複素環基を示す。また、Ｚ₁とＺ₂及びＺ₃とＺ₄は共同でそれぞれが結合しているビフェニル骨格を介して、フルオレン骨格やジヒドロフェナントレン骨格等の環状構造を形成してもよい。
【００４１】
式（１）〜（３）において有してもよい置換基としては、メチル基、エチル基、プロピル基及びブチル基等のアルキル基、ベンジル基、フェネチル基及びナフチルメチル基等のアラルキル基、フェニル基、ナフチル基、アンスリル基、ピレニル基、フルオレニル基、カルバゾリル基、ジベンゾフリル基及びジベンゾチオフェニル基等の芳香環基、メトキシ基、エトキシ基及びプロポキシ基等のアルコキシ基、フェノキシ基及びナフトキシ基等のアリールオキシ基、フッ素、塩素、臭素及びヨウ素等のハロゲン原子、ニトロ基及びシアノ基等が挙げられる。
【００４２】
ただし、本発明においては、ヒドロキシアルキル基及びヒドロキシアルコキシ基より選ばれる置換基の少なくとも１つ有する電荷輸送材料であればいかなる構造のものでもよく、式（１）〜（３）に示される構造に限定されるものではない。
【００４３】
本発明に用いられる式（１）〜（３）の特定の構造を有する電荷輸送材料は、保護層を作製するための塗工液中に均一に溶解又は分散させ、塗布して形成する。式（１）〜（３）の電荷輸送材料と硬化性アクリル樹脂バインダーの混合割合は、質量比で、電荷輸送材料／アクリル樹脂バインダー＝０．１／１０〜２０／１０が好ましく、特には０．５／１０〜１０／１０であることが好ましい。アクリル樹脂バインダー対して電荷輸送材料が少な過ぎると残留電位低下の効果が小さくなり、多過ぎると保護層の強度を弱める可能性がある。
【００４４】
以下に、本発明で用いられるヒドロキシアルキル基及びヒドロキシアルコキシ基より選ばれる置換基の少なくとも１つ有する電荷輸送材料の具体例を例示するが、本発明はこれらの化合物のみに限定されるものではない。
【００４５】
【化７】

【００４６】
【化８】

【００４７】
【化９】

【００４８】
【化１０】

【００４９】
【化１１】

【００５０】
【化１２】

【００５１】
【化１３】

【００５２】
【化１４】

【００５３】
【化１５】

【００５４】
【化１６】

【００５５】
【化１７】

【００５６】
【化１８】

【００５７】
【化１９】

【００５８】
【化２０】

【００５９】
【化２１】

【００６０】
【化２２】

【００６１】
【化２３】

【００６２】
【化２４】

【００６３】
【化２５】

【００６４】
【化２６】

【００６５】
【化２７】

【００６６】
【化２８】

【００６７】
【化２９】

【００６８】
【化３０】

【００６９】
本発明の電子写真感光体の保護層には、硬化性アクリル樹脂とヒドロキシアルキル基及びヒドロキシアルコキシ基より選ばれる置換基の少なくとも１つ有する電荷輸送材料を含有するが、更に導電性粒子を含有させることにより、電子写真感光体の残留電位の低下を高い次元で達成することができる。
【００７０】
本発明において保護層に用いられる導電性粒子としては、金属、金属酸化物及びカーボンブラックが挙げられる。金属としては、アルミニウム、亜鉛、銅、クロム、ニッケル、銀及びステンレス等、又はこれらの金属をプラスチックの粒子の表面に蒸着したもの等が挙げられる。金属酸化物としては、酸化亜鉛、酸化チタン、酸化スズ、酸化アンチモン、酸化インジウム、酸化ビスマス、スズをドープした酸化インジウム、アンチモンやタンタルをドープした酸化スズ及びアンチモンをドープした酸化ジルコニウム等が挙げられる。これらは、単独で用いることも、２種以上を組み合わせて用いることもできる。２種以上を組み合わせて用いる場合は、単に混合しても、固溶体や融着の形にしてもよい。
【００７１】
また、本発明においては、上述した導電性粒子の中でも透明性の点で金属酸化物を用いることが好ましい。更に、これら金属酸化物の中でも酸化スズを用いることが特に好ましい。この酸化スズは、分散性や液安定性を改良する目的で後述の表面処理されていてもよく、抵抗制御性を良くする目的でアンチモンやタンタルをドープされていてもよい。
【００７２】
本発明において用いられる導電性粒子の平均粒径は、保護層の透明性の点で０．３μｍ以下が好ましく、特には０．１μｍ以下が好ましい。
【００７３】
樹脂と導電性粒子との割合は、直接的に保護層の体積抵抗率を決定する値であり、保護層の体積抵抗率が１０¹⁰〜１０¹⁵Ω・ｃｍの範囲になるように設定するのが好ましく、特には１０¹¹〜１０¹⁴Ω・ｃｍにすることが好ましい。
【００７４】
膜強度的には、導電性粒子の量が増えれば増えるほど弱くなるため、導電性粒子の量は、保護層の体積抵抗及び残留電位が許容できる範囲において、少なくする方が好ましい。
【００７５】
更に保護層表面に潤滑性を付与する目的で、フッ素原子含有樹脂粒子、シリカ粒子、シリコーン樹脂粒子及びアルミナ粒子の少なくとも１種を混合して用いてもよい。
【００７６】
本発明に用いられるフッ素原子含有樹脂粒子としては、四フッ化エチレン、三フッ化塩化エチレン樹脂、六フッ化エチレンプロピレン樹脂、フッ化ビニル樹脂、フッ化ビニリデン樹脂、二フッ化二塩化エチレン樹脂及びこれらの共重合体の中から１種あるいは２種以上を適宜選択するのが好ましいが、特に、四フッ化エチレン樹脂及びフッ化ビニリデン樹脂が好ましい。樹脂粒子の分子量や粒子の粒径は適宜選択することができ、特に制限されるものではない。
【００７７】
また、潤滑性粒子の分散性安定、表面の滑り性改良、塗工面のレベリング性向上等の目的でフッ素原子含有化合物、シロキサン化合物を合わせて含有することができる。
【００７８】
潤滑性粒子を導電性粒子と共に樹脂溶液中で相互の粒子を凝集させないために、フッ素原子含有化合物を導電性粒子の分散時に添加したり、また、導電性粒子の表面をフッ素原子含有化合物で表面処理するとよい。フッ素原子含有化合物を添加又は導電性粒子に表面処理を行うことにより、フッ素原子含有化合物のない場合に比べて、樹脂溶液中での導電性粒子とフッ素原子含有樹脂粒子の分散性及び分散安定性が格段に向上した。また、フッ素原子含有化合物を添加し導電性粒子を分散した液、又は表面処理を施した導電性粒子を分散した液に、フッ素原子含有樹脂粒子を分散することによって分散粒子の二次粒子の形成もなく、経時的にも非常に安定した分散性の良好な塗工液が得られる。
【００７９】
本発明におけるフッ素原子含有化合物としては、含フッ素シランカップリング剤、フッ素変性シリコーンオイル及びフッ素系界面活性剤等が挙げられる。これらの化合物の好ましい化合物例を表１〜表３に挙げるが、本発明はこれらの化合物に限定されるものではない。
【００８０】
【表１】

【００８１】
【表２】

【００８２】
【表３】

【００８３】
導電性粒子の表面処理方法としては、導電性粒子と表面処理剤とを適当な溶剤中で混合、分散し、表面処理剤を導電性粒子表面に付着させる。分散の方法としては、ボールミルやサンドミル等の通常の分散手段を用いることができる。次に、この分散溶液から溶剤を除去し、導電性粒子表面に固着させればよい。また、必要に応じて、この後に更に熱処理を行ってもよい。また、処理液中には反応促進のための触媒を添加することもできる。更に、必要に応じて表面処理後の導電性粒子に更に粉砕処理を施すことができる。
【００８４】
導電性粒子に対するフッ素原子含有化合物の割合は、粒子の粒径、形状及び表面積等にも影響を受けるが、表面処理済みの導電性粒子全質量に対し１〜６５質量％が好ましく、特には１〜５０質量％が好ましい。
【００８５】
更に、本発明においては、より環境安定性のある保護層とするために、下記式（４）で示されるシロキサン化合物を導電性粒子分散時に添加したり、又は、予め表面処理を施した導電性粒子を混合することにより、更に環境安定性により優れた保護層を得ることができる。
【００８６】
【化３１】

【００８７】
式中、Ａは水素原子又はメチル基であり、かつ、Ａの全部における水素原子の割合は０．１〜５０％の範囲、ｎは０以上の整数である。
【００８８】
このシロキサン化合物を添加後に分散した塗工液、又はこれを表面処理した導電性微粒子を溶剤に溶かした結着樹脂中に分散することによって、分散粒子の二次粒子の形成もなく、経時的にも安定した分散性の良好な塗工液が得られ、また、この塗工液より形成した保護層は透明性が高く、耐環境性に特に優れた膜が得られた。
【００８９】
式（４）で示されるシロキサン化合物の分子量は特に制限されるものではないが、表面処理をする場合は、その容易さからは粘度が高過ぎない方がよく、重量平均分子量で数百〜数万程度が適当である。
【００９０】
表面処理の方法としては、湿式と乾式の二通りがある。湿式では導電性粒子を式（４）で示されるシロキサン化合物とを溶剤中で分散し、該シロキサン化合物を粒子表面に付着させる。分散の手段としては、ボールミルやサンドミル等の一般の分散手段を使用することができる。次に、この分散溶液を導電性粒子表面に固着させる。この熱処理においては、シロキサン中のＳｉ−Ｈ結合が熱処理過程において空気中の酸素によって水素原子の酸化が起こり、新たなシロキサン結合ができる。その結果、シロキサンが３次元構造にまで発達し、導電性粒子表面がこの網状構造で包まれる。このように表面処理は、該シロキサン化合物を導電性粒子表面に固着させることによって完了するが、必要に応じて処理後の微粒子に粉砕処理を施してもよい。乾式処理においては、溶剤を用いずに該シロキサン化合物と導電性粒子とを混合し混練を行うことによってシロキサン化合物を粒子表面に付着させる。その後は、湿式処理と同様に熱処理や粉砕処理を施して表面処理を完了する。
【００９１】
保護層の塗工液を分散する溶剤としては、アクリル樹脂モノマー等を良く溶解し、式（１）〜（３）で示される電荷輸送材料も良く溶解し、導電性粒子を用いる場合はその分散性が良く、更にフッ素原子含有化合物、フッ素原子含有樹脂粒子、シロキサン化合物を用いる場合はその相溶性や処理性が良好で、なお更に保護層の塗工液と接触する電荷輸送層に悪影響を与えない溶剤が好ましい。
【００９２】
従って、溶剤としては、メタノール、エタノール及び２−プロパノール等のアルコール類、アセトン及びメチルエチルケトン等のケトン類、酢酸メチル及び酢酸エチル等のエステル類、テトラヒドロフラン及びジオキサン等のエーテル類、トルエン及びキシレン等の芳香族炭化水素類又はクロロベンゼン及びジクロロメタン等のハロゲン系炭化水素類等が使用可能であり、更にこれらを混合して用いてもよい。これらの中でも最も好適な溶剤は、メタノール、エタノール及び２−プロパノール等のアルコール類である。
【００９３】
本発明の保護層の塗布方法としては、浸漬コーティング法、スプレーコーティング法、スピンナーコーティング法、ローラーコーティング法、マイヤーバーコーティング法及びブレードコーティング法等の一般的な塗工方法を用いることができる。
【００９４】
本発明の保護層の膜厚は、薄過ぎると電子写真感光体の耐久性を損ない、厚過ぎると保護層を設けたことによる残留電位が上昇するため、適度な厚さにする必要がある。具体的には０．１μｍ〜１０μｍの範囲が好ましく、特には０．５μｍ〜７μｍの範囲が好ましい。
【００９５】
本発明においては、前記保護層中に、帯電時に発生するオゾンやＮＯｘ等の活性物質の付着による表面層の劣化等を防止する目的で、酸化防止剤の添加材を加えてもよい。
【００９６】
次に、感光層について以下に説明する。
【００９７】
本発明の電子写真感光体は、主に積層構造を有することが好ましい。図１（ａ）の電子写真感光体は、導電性支持体４の上に電荷発生層３、電荷輸送層２が順に設けており、更に最表面に保護層１を設けている。また、図１（ｂ）及び（ｃ）の様に導電性支持体と電荷発生層の間に、結着層５、更には干渉縞防止等を目的とする下引き層６を設けてもよい。
【００９８】
導電性支持体４としては、支持体自身が導電性を持つもの、例えば、アルミニウム、アルミニウム合金及びステンレス等の金属を用いることができ、その他にアルミニウム、アルミニウム合金又は酸化インジウム−酸化スズ合金等を真空蒸着によって被膜形成された層を有する前記導電性支持体やプラスチック、導電性微粒子（例えば、カーボンブラック、酸化スズ、酸化チタン及び銀粒子等）を適当なバインダーと共にプラスチックや紙に含浸した支持体、導電性バインダーを有するプラスチック等を用いることができる。
【００９９】
また、導電性支持体と感光層の間には、バリアー機能と接着機能を持つ結着層（接着層）を設けることができる。結着層は、感光層の接着性改良、塗工性改良、支持体の保護、支持体の欠陥の被覆、支持体からの電荷注入性改良、感光層の電気的破壊に対する保護等のために形成される。結着層は、カゼイン、ポリビニルアルコール、エチルセルロース、エチレン−アクリル酸コポリマー、ポリアミド、変性ポリアミド、ポリウレタン、ゼラチン又は酸化アルミニウム等によって形成できる。結着層の膜厚は、５μｍ以下が好ましく、特には０．１〜３μｍが好ましい。
【０１００】
本発明に用いられる電荷発生材料としては、（１）モノアゾ、ジスアゾ及びトリスアゾ等のアゾ系顔料、（２）金属フタロシアニン及び非金属フタロシアニン等のフタロシアニン系顔料、（３）インジゴ及びチオインジゴ等のインジゴ系顔料、（４）ペリレン酸無水物及びペリレン酸イミド等のペリレン系顔料、（５）アンスラキノン及びピレンキノン等の多環キノン系顔料、（６）スクワリリウム色素、（７）ピリリウム塩及びチアピリリウム塩類、（８）トリフェニルメタン系色素、（９）セレン、セレン−テルル及びアモルファスシリコン等の無機物質、（１０）キナクリドン顔料、（１１）アズレニウム塩顔料、（１２）シアニン染料、（１３）キサンテン色素、（１４）キノンイミン色素、（１５）スチリル色素、（１６）硫化カドミウム及び（１７）酸化亜鉛等が挙げられる。
【０１０１】
電荷発生層に用いる結着樹脂としては、例えば、ポリカーボネート樹脂、ポリエステル樹脂、ポリアリレート樹脂、ブチラール樹脂、ポリスチレン樹脂、ポリビニルアセタール樹脂、ジアリルフタレート樹脂、アクリル樹脂、メタクリル樹脂、酢酸ビニル樹脂、フェノール樹脂、シリコーン樹脂、ポリスルホン樹脂、スチレン−ブタジエン共重合体樹脂、アルキッド樹脂、エポキシ樹脂、尿素樹脂及び塩化ビニル−酢酸ビニル共重合体樹脂等が挙げられるが、これらに限定されるものではない。これらは単独、混合あるいは共重合体ポリマーとして１種又は２種以上用いることができる。
【０１０２】
電荷発生層用塗工液に用いる溶剤は、使用する樹脂や電荷発生材料の溶解性や分散安定性から選択されるが、有機溶剤としてはアルコール類、スルホキシド類、ケトン類、エーテル類、エステル類、脂肪族ハロゲン化炭化水素類又は芳香族化合物等を用いることができる。
【０１０３】
電荷発生層３は、前記の電荷発生材料を０．３〜４倍量の結着樹脂及び溶剤と共に、ホモジナイザー、超音波、ボールミル、サンドミル、アトライター又はロールミル等の方法で十分に分散し、塗布、乾燥されて形成される。その厚みは、５μｍ以下が好ましく、特には０．０１〜１μｍの範囲が好ましい。
【０１０４】
また、電荷発生層には、種々の増感剤、酸化防止剤、紫外線吸収剤、可塑剤及び公知の電荷発生材料を必要に応じて添加することもできる。
【０１０５】
用いられる電荷輸送材料としては、各種トリアリールアミン系化合物、各種ヒドラゾン系化合物、各種スチリル系化合物、各種スチルベン系化合物、各種ピラゾリン系化合物、各種オキサゾール系化合物、各種チアゾール系化合物及び各種トリアリールメタン系化合物等が挙げられる。
【０１０６】
電荷輸送層２を形成するのに用いられる結着樹脂としては、アクリル樹脂、スチレン系樹脂、ポリエステル、ポリカーボネート樹脂、ポリアリレート、ポリサルホン、ポリフェニレンオキシド、エポキシ樹脂、ポリウレタン樹脂、アルキド樹脂及び不飽和樹脂等から選ばれる樹脂が好ましい。特に好ましい樹脂としては、ポリメチルメタクリレート、ポリスチレン、スチレン−アクリロニトリル共重合体、ポリカーボネート樹脂及びジアリルフタレート樹脂が挙げられる。
【０１０７】
電荷輸送層２は、一般的には前記の電荷輸送材料と結着樹脂を溶剤に溶解し、塗布して形成する。電荷輸送材料と結着樹脂との混合割合は、２：１〜１：２程度である。溶剤としては、アセトン及びメチルエチルケトン等のケトン類、酢酸メチル及び酢酸エチル等のエステル類、トルエン及びキシレン等の芳香族炭化水素類、クロロベンゼン、クロロホルム及び四塩化炭素等の塩素系炭化水素類等が用いられる。この溶液を塗布する際には、例えば、浸漬コーティング法、スプレーコーティング法及びスピンナーコーティング法等のコーティング法を用いることができ、乾燥は１０℃〜２００℃が好ましく、より好ましくは２０℃〜１５０℃の範囲の温度で、５分〜５時間が好ましく、より好ましくは１０分〜２時間の時間で送風乾燥又は静止乾燥下で行うことができる。
【０１０８】
電荷輸送層は、上述の電荷発生層と電気的の接続されており、電界の存在下で電荷発生層から注入された電荷キャリアを受け取ると共に、これ等の電荷キャリアを保護層との界面まで輸送する機能を有している。この電荷輸送層は電荷キャリアを輸送する限界があるので必要以上に膜厚を厚くすることができないが、５〜４０μｍが好ましく、特には７〜３０μｍの範囲が好ましい。
【０１０９】
更に、電荷輸送層中に酸化防止剤、紫外線吸収剤、可塑剤及び公知の電荷輸送材料を必要に応じて添加することもできる。
【０１１０】
本発明では更に、この電荷輸送層の上に前記保護層を塗布、硬化させて成膜することで完成される。
【０１１１】
図２に本発明の電子写真感光体を有するプロセスカートリッジを備えた電子写真装置の概略構成を示す。
【０１１２】
図２において、１１はドラム状の本発明の電子写真感光体であり、軸１２を中心に矢印方向に所定の周速度で回転駆動される。電子写真感光体１１は、回転過程において、一次帯電手段１３によりその周面に正又は負の所定電位の均一帯電を受け、次いで、スリット露光やレーザービーム走査露光等の露光手段（不図示）から出力される目的の画像情報の時系列電気デジタル画像信号に対応して強度変調された露光光１４を受ける。こうして電子写真感光体１１の周面に対し、目的の画像情報に対応した静電潜像が順次形成されていく。
【０１１３】
形成された静電潜像は、次いで現像手段１５によりトナー現像され、不図示の給紙部から電子写真感光体１１と転写手段１６との間に電子写真感光体１１の回転と同期して取り出されて給送された転写材１７に、電子写真感光体１１の表面に形成担持されているトナー画像が転写手段１６により順次転写されていく。
【０１１４】
トナー画像の転写を受けた転写材１７は、電子写真感光体面から分離されて像定着手段１８へ導入されて像定着を受けることにより画像形成物（プリント、コピー）として装置外へプリントアウトされる。
【０１１５】
像転写後の電子写真感光体１１の表面は、クリーニング手段１９によって転写残りトナーの除去を受けて清浄面化され、更に前露光手段（不図示）からの前露光光２０により除電処理された後、繰り返し画像形成に使用される。なお、一次帯電手段１３が帯電ローラー等を用いた接触帯電手段である場合は、前露光は必ずしも必要ではない。
【０１１６】
本発明においては、上述の電子写真感光体１１、一次帯電手段１３、現像手段１５及びクリーニング手段１９等の構成要素のうち、複数のものを容器に納めてプロセスカートリッジとして一体に結合して構成し、このプロセスカートリッジを複写機やレーザービームプリンター等の電子写真装置本体に対して着脱自在に構成してもよい。例えば、一次帯電手段１３、現像手段１５及びクリーニング手段１９の少なくとも１つを電子写真感光体１１と共に一体に支持してカートリッジ化して、装置本体のレール等の案内手段２２を用いて装置本体に着脱自在なプロセスカートリッジ２１とすることができる。
【０１１７】
また、露光光１４は、電子写真装置が複写機やプリンターである場合には、原稿からの反射光や透過光、あるいは、センサーで原稿を読取り、信号化し、この信号に従って行われるレーザービームの走査、ＬＥＤアレイの駆動又は液晶シャッターアレイの駆動等により照射される光である。
【０１１８】
本発明の電子写真感光体は、電子写真複写機に利用するのみならず、レーザービームプリンター、ＣＲＴプリンター、ＬＥＤプリンター、ＦＡＸ、液晶プリンター及びレーザー製版等の電子写真応用分野にも幅広く適用し得るものである。
【０１１９】
【実施例】
以下に、具体的な実施例を挙げて本発明を更に詳細に説明する。ただし、本発明の実施の形態は、これらに限定されるものではない。なお、実施例中の「部」は「質量部」を意味する。
【０１２０】
（実施例１）
φ３０ｍｍ×２６０．５ｍｍのアルミニウムシリンダー（ＪＩＳ Ａ３００３アルミニウム合金）を支持体として、この上にポリアミド樹脂（商品名：アミランＣＭ８０００、東レ製）の５質量％メタノール溶液を浸漬法で塗布し、熱風乾燥し、膜厚が０．５μｍの下引き層を形成した。
【０１２１】
次に、電荷発生材料として下記式（５）で示されるＣｕＫα特性Ｘ線回折におけるブラッグ角（２θ±０．２゜）の９．６°及び２７．２゜に強いピークを有する結晶型であるオキシチタニウムフタロシアニン顔料４部、
【０１２２】
【化３２】

ポリビニルブチラール樹脂ＢＸ−１（積水化学（株）製）２部及びシクロヘキサノン１１０部を、φ１ｍｍガラスビーズを用いてサンドミルで、４．５時間分散した。その後、酢酸エチル１３０部で希釈し電荷発生層用塗工液とした。上記塗工液を先の下引き層上に浸漬法で塗布し、膜厚が０．１８μｍの電荷発生層を形成した。
【０１２３】
次いで、下記式（６）で示される電荷輸送材料１０部
【０１２４】
【化３３】

及びビスフェノールＺ型ポリカーボネート（商品名：Ｚ−２００、三菱ガス化学製）１０部を、モノクロロベンゼン６０部／ジクロロメタン２０部に溶解した。この塗工液を、前記電荷発生層上に浸漬塗布し、１１０℃で１時間で熱風乾燥し、膜厚が２０μｍの電荷輸送層を形成した。
【０１２５】
次に、保護層として、下記式（７）で示される硬化性アクリル樹脂３０部と光重合開始剤として２−メチルチオキサントン５．２部を溶解し、更にヒドロキシアルキル基を有する電荷輸送材料として化合物例Ｎｏ．１−２５を２１部溶解し、保護層用塗工液を作製した。
【０１２６】
【化３４】

【０１２７】
この塗工液を前記電荷輸送層上に浸漬塗布して膜を形成させ、続いて高圧水銀灯にて８００ｍＷ／ｃｍ²の光強度で６０秒間光硬化を行い、その後１２０℃で２時間熱風乾燥し、膜厚が３μｍ保護層を形成し、電子写真感光体を作製し、評価した。保護層塗工液の分散性は良好で、作製された保護層はムラのない均一な膜であった。
【０１２８】
保護層の体積抵抗率の測定は、ポリエチレンテレフタレートフィルム上に１８０μｍのギャップをもつ櫛形電極を金蒸着により作製し、その上に保護層塗工液を塗布し、硬化条件及び膜厚等は上記電子写真感光体作製時と同様にして行い、サンプルを作製した。
【０１２９】
体積抵抗率の測定は、前記サンプルをビューレット・パッカード社製ＰＡメーター４１４０Ｂを用いて１００Ｖ印加で測定した。測定環境は温度／湿度が２３℃／５０％ＲＨ、２３℃／５％ＲＨ及び３０℃／８０％ＲＨの３環境下で測定した。
【０１３０】
保護層の硬度は、ドイツ、ＦＩＳＣＨＥＲ社製硬度計（Ｈ１００ＶＰ−ＨＣＵ）を用いて測定した。この測定による硬度は、次のようにして定められる。
【０１３１】
すなわち、四角錐で先端の対面角１３０°のダイヤモンド圧子で荷重をかけて保護層の膜に１μｍまで押し込み、圧子の幾何学的形状から計算された圧痕の表面積とその時の荷重から次の式のように求まる；
ユニバーサル硬さ値ＨＵ（Ｎ／ｍｍ²）＝荷重（Ｎ）／荷重下での圧痕の表面積（ｍｍ²）
【０１３２】
実施例の保護層の硬度測定は、ガラスプレート上に保護層塗工液を塗布し、硬化条件は上記電子写真感光体作製時と同様にして行い、この保護層膜を３〜４回塗工して膜厚を約１０μｍにして硬度測定サンプルとした。
【０１３３】
電子写真特性の評価は、キヤノン（株）製ＬＢＰ−ＮＸを用いた。評価として、初期転写効率、更に３０００枚の耐久による削れ量の測定及び３０℃／８０％環境下での画像特性を見た。更に、残留電位（Ｖｒ）の測定は、２３℃／５％ＲＨの環境下でジェンテック社製ドラム試験器により、強露光後０．２秒の位置での残留電位を測定した。
【０１３４】
抵抗測定及び膜硬度の測定結果を表４、電子写真特性の結果を表５に示す。
【０１３５】
（実施例２〜７）
実施例１において用いたヒドロキシアルキル基を有する電荷輸送材料（化合物例Ｎｏ．１−２５）の代わりに、表４に示されるヒドロキシアルキル基及びヒドロキシアルコキシ基より選ばれる置換基の少なくとも１つ有する電荷輸送材料に代えた以外は、実施例１と同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１３６】
（実施例８）
電荷輸送層までを実施例１と同様にして作製した。
【０１３７】
次に、保護層として、アンチモンドープ酸化スズ超微粒子１００部を下記式（８）で示されるフッ素原子含有化合物（商品名：ＬＳ−１０９０、信越シリコーン（株）製）７部で表面処理した（処理量７％）処理済み酸化スズ微粒子３５部と
【０１３８】
【化３５】

エタノール１５０部を、サンドミルにて６６時間かけて分散を行い、更に、ポリテトラフルオロエチレン微粒子（平均粒径０．１８μｍ）２０部を加えて、更に１２時間サンドミルで分散を行った。その後、樹脂成分として実施例１で用いた硬化性アクリル樹脂３１部と２−メチルチオキサンソン５．４部を溶解し、更に、ヒドロキシアルキル基を有する電荷輸送材料として化合物例Ｎｏ．１−２２を１５部溶解し保護層用塗工液とした。
【０１３９】
この塗工液を用いて、先の電荷輸送層上に浸漬塗布法により、膜を形成した後、高圧水銀灯にて８００ｍＷ／ｃｍ²の光強度で、６０秒間光硬化を行い、その後１２０℃で２時間熱風乾燥し、膜厚が３μｍの保護層を形成した。保護層塗工液の分散性は良好で、作製された保護層はムラのない均一な膜であった。その後、保護層の体積抵抗率とその環境変動、保護層の硬度、耐久性、電子写真特性を実施例１と同様に評価した。結果を同様に表４及び表５に示す。
【０１４０】
（実施例９〜１４）
実施例８において用いたヒドロキシアルキル基を有する電荷輸送材料（化合物例Ｎｏ．１−２２）の代わりに、表４に示されるヒドロキシアルキル基及びヒドロキシアルコキシ基より選ばれる置換基の少なくとも１つ有する電荷輸送材料に代えた以外は、実施例８と同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１４１】
（実施例１５〜１７）
実施例８、１０及び１２において、前記式（８）で示される化合物で表面処理した（処理量７％）アンチモンドープ酸化スズ微粒子を２０部に減らし、メチルハイドロジェンシリコーンオイル（商品名：ＫＦ９９、信越シリコーン（株）製）で処理した（処理量２０％）アンチモンドープ酸化スズ微粒子１５部を更に添加分散して塗工液を作製した以外は、実施例８、１０及び１２と全く同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１４２】
（実施例１８〜２０）
実施例８、１０、１２において、前記式（８）で示される化合物で表面処理したアンチモンドープ酸化スズ微粒子に代えて、表面処理を施す以前のアンチモンドープ酸化スズ微粒子（商品名：Ｔ−１、三菱マテリアル（株）製）３５部、前記式（８）で示されるフッ素原子含有化合物（商品名：ＬＳ−１０９０、信越シリコーン（株）製）３．５部を添加し分散した以外は、実施例８、１０及び１２と全く同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１４３】
（実施例２１〜２３）
実施例１８〜２０において、更にメチルハイドロジェンシリコーンオイル（商品名：ＫＦ９９、信越シリコーン（株）製）１．５部を添加し分散した以外は、実施例１８〜２０と全く同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１４４】
（実施例２４）
電荷輸送層までを実施例１と同様にして作製した。
【０１４５】
次に、保護層として、アンチモンドープ酸化スズ微粒子（商品名：Ｔ−１、三菱マテリアル（株）製）３５部とトルエン１５０部を、サンドミルで４８時間かけて分散を行い、その後、樹脂成分として実施例１で用いられた硬化型アクリル樹脂３１部と光重合開始剤として２−メチルチオキサンソン５．４部を溶解し、更に、ヒドロキシアルキル基を有する電荷輸送材料として化合物例Ｎｏ．３−２を１５部溶解し、トルエン２１０部／アセトン１６０部を加えて希釈し保護層用塗工液とした。この塗工液を用いて、先の電荷輸送層上にスプレー塗布法により、膜を形成した後、高圧水銀灯にて８００ｍＷ／ｃｍ²の光強度で、６０秒間光硬化を行い、その後１２０℃で２時間熱風乾燥し、膜厚が３μｍの保護層を形成した。保護層塗工液の分散性は良好で、作製された保護層はムラのない均一な膜であった。更に、抵抗測定用サンプル、硬度測定用サンプルを実施例１と同様にして作製し、実施例１と同様に評価を行った。結果を同様に表４及び表５に示す。
【０１４６】
（実施例２５及び２６）
実施例２４において用いたヒドロキシアルキル基を有する電荷輸送材料（化合物例Ｎｏ．３−２）の代わりに、表４に示されるヒドロキシアルキル基及びヒドロキシアルコキシ基より選ばれる置換基の少なくとも１つ有する電荷輸送材料に代えた以外は、実施例２４と同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１４７】
（比較例１）
実施例１において、電荷輸送材料を無添加とした以外は実施例１と同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１４８】
（比較例２）
実施例８において、電荷輸送材料を無添加とした以外は実施例８と同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１４９】
（比較例３〜６）
実施例８において用いたヒドロキシアルキル基を有する電荷輸送材料（化合物例Ｎｏ．１−２２）の代わりに、下記式で表される比較化合物１〜４に代えた以外は、実施例８と同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１５０】
【化３６】

【０１５１】
（比較例７）
実施例１における保護層の代わりに、実施例８で用いた処理済み酸化スズ微粒子３５部と１，４−ジオキサン１５０部を、サンドミルにて６６時間かけて分散を行い、更に、ポリテトラフルオロエチレン微粒子（平均粒径０．１８μｍ）２０部を加えて、更に１２時間サンドミルで分散を行った。その後、樹脂成分として硬化性アクリル樹脂の代わりにＰＭＭＡ（商品名：Ｊ−８９９、星光化学社製）３１部を溶解し、更に、ヒドロキシアルキル基を有する電荷輸送材料として化合物例Ｎｏ．１−２２を１５部溶解し、更に１時間サンドミルで分散を行い、１，４−ジオキサン３７０部で希釈して保護層用塗工液とした。この塗工液を用いて、電荷輸送層上にスプレー塗布法により、膜を形成した後に、１００℃で３０分間熱風乾燥し、膜厚が３μｍの保護層を有する電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１５２】
（比較例８）
実施例１において、保護層を塗布しなかった以外は、実施例１と全く同様にして電子写真感光体等を作製し、評価した。結果を同様に表４及び表５に示す。
【０１５３】
【表４】

【０１５４】
【表５】

【０１５５】
表４及び表５に示すように、本発明の保護層を有する電子写真感光体を用いることにより、保護層の抵抗の環境安定性に優れ、残留電位の上昇が最も厳しい低湿環境下でも残留電位が低く、高転写効率であり、更に、高湿下での画像流れもなく、膜強度を保ち、削れ量を維持し、高耐久で、高安定で、良好な画像を得ることができた。
【０１５６】
【発明の効果】
上述したように、本発明におけるように、本発明の電子写真感光体を用いることにより、保護層の抵抗の環境安定性に優れ、残留電位の上昇が最も厳しい低湿環境下でも残留電位が低く、高転写効率であり、更に高湿下での画像流れもなく、膜強度を保ち、削れ量を維持し、高耐久で、高安定で、良好な画像を得ることができる電子写真感光体を提供することが可能となった。
【０１５７】
また、該電子写真感光体を有するプロセスカートリッジ及び電子写真装置において同様に顕著な効果を奏することができた。
【図面の簡単な説明】
【図１】本発明の電子写真感光体の層構成を示す図である。
【図２】本発明の電子写真感光体を有するプロセスカートリッジを備えた電子写真装置の概略構成の例を示す図である。
【符号の説明】
１ 保護層
２ 電荷輸送層
３ 電荷発生層
４ 導電性支持体
５ 結着層
６ 下引き層
１１ 電子写真感光体
１２ 軸
１３ 帯電手段
１４ 露光光
１５ 現像手段
１６ 転写手段
１７ 転写材
１８ 定着手段
１９ クリーニング手段
２０ 前露光光
２１ プロセスカートリッジ
２２ 案内手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus, and more specifically, an electrophotographic photosensitive member having a protective layer containing a specific resin and a specific compound, a process cartridge having the electrophotographic photosensitive member, and an electronic The present invention relates to a photographic apparatus.
[0002]
[Prior art]
In recent years, research and development of electrophotographic photoreceptors using organic photoconductive materials have been actively conducted due to advantages such as high safety, excellent productivity and low cost, and many proposals have been made so far. It has been put into practical use.
[0003]
However, an electrophotographic photoreceptor mainly composed of a photoconductive polymer typified by poly-N-vinylcarbazole and a charge transfer complex formed from 2,4,7-trinitrofluorene or the like is sensitive and durable. It was not always satisfactory in terms of properties and residual potential.
[0004]
On the other hand, the function-separated electrophotographic photosensitive member in which the charge generation function and the charge transport function are assigned to different materials significantly improves the sensitivity and durability, which have been regarded as the disadvantages of conventional organic electrophotographic photosensitive members. Brought. In addition, the function-separated type electrophotographic photoreceptor has the advantage that the material selection range of each of the charge generation material and the charge transport material is wide, and an electrophotographic photoreceptor having arbitrary characteristics can be produced relatively easily. Yes.
[0005]
As charge generation materials, various azo pigments, polycyclic quinone pigments, phthalocyanine pigments, cyanine dyes, squaric acid dyes, pyrylium salt dyes, and the like are known. As charge transport materials, pyrazoline compounds, hydrazone compounds, triphenylamine compounds, and the like are known.
[0006]
By the way, with the recent improvement in image quality, high speed and high durability, organic electrophotographic photoreceptors are also required to have further improved mechanical durability.
[0007]
In recent years, printers, copiers, facsimiles, and the like using electrophotographic photoreceptors have been used in a wide variety of fields, and it has been more strictly required to always provide stable images even in more various environments. Therefore, the possibility of exposure to chemical, electrical, and mechanical impacts on the surface characteristics of the photosensitive layer is increased, and the requirements for the surface layer are becoming strict.
[0008]
The electrophotographic photoreceptor is required to have durability against the above-described electrical and mechanical external forces that are directly applied. Specifically, durability against surface abrasion and scratches due to rubbing, and deterioration of the surface layer due to adhesion of active substances such as ozone and NOx generated during charging is required.
[0009]
Furthermore, processes such as charging, exposure, development, transfer, cleaning, and static elimination are repeatedly applied to the electrophotographic photosensitive member. The electrostatic latent image formed by charging and exposure becomes a toner image by a fine particle developer called toner. Further, the toner image is transferred onto a transfer material such as paper by a transfer unit, but not all the toner is transferred, and a part of the toner image remains as residual toner on the electrophotographic photosensitive member.
[0010]
If the amount of the residual toner is large, the image on the transfer material becomes a so-called bulging shape in which further transfer failure occurs, and not only the image uniformity is lost, but also the toner is fused or filmed to the electrophotographic photosensitive member. The problem of occurrence occurs. For these problems, it is required to improve the releasability of the surface layer of the electrophotographic photosensitive member.
[0011]
In order to satisfy the above-described requirements for the electrophotographic photoreceptor, attempts have been made to provide various protective layers. Among them, many protective layers mainly composed of a resin have been proposed. For example, Japanese Patent Application Laid-Open No. 57-30846 discloses a protective layer in which volume resistance can be controlled by adding a metal oxide as a conductive powder to a resin.
[0012]
Dispersing the metal oxide in the protective layer of the electrophotographic photosensitive member is to control the volume resistance of the protective layer itself and to prevent an increase in the residual potential in the electrophotographic photosensitive member due to repetition of the electrophotographic process. On the other hand, an appropriate volume resistivity of a protective layer for an electrophotographic photoreceptor is 10 ^Ten -10 ¹⁵ It is known to be Ω · cm. However, in the volume resistivity in the above range, the volume resistance of the protective layer is easily affected by ion conduction, and therefore the volume resistance tends to change greatly due to environmental changes. In particular, when the metal oxide is dispersed in the film, the water resistance of the surface of the metal oxide is high, so that the volume resistance of the protective layer is reduced in all environments and when the electrophotographic process is repeated. It has been very difficult to keep the above in the above range.
[0013]
Particularly under high humidity, the volume resistance gradually decreases when left standing, or the active substance such as ozone or NOx generated by charging repeatedly adheres to the surface, thereby reducing the volume resistance of the electrophotographic photoreceptor surface. In addition, the toner releasability from the surface layer is reduced, so that defects such as so-called image flow and image blur occur, and image uniformity is insufficient.
[0014]
In general, when the particles are dispersed in the protective layer, the particle diameter of the particles is preferably smaller than the wavelength of the incident light, that is, 0.3 μm or less in order to prevent scattering of incident light by the dispersed particles. . However, the metal oxide particles usually tend to aggregate in the resin solution, and are difficult to uniformly disperse. Even if dispersed once, secondary aggregation and precipitation are likely to occur, so fine particles having a particle size of 0.3 μm or less are good. It was very difficult to produce a dispersion film stably. Furthermore, it is preferable to disperse ultrafine particles having a small particle size (primary particle size of 0.1 μm or less) from the viewpoint of improving transparency and conductivity uniformity, but the dispersibility and dispersion stability of such ultrafine particles are further improved. There was a tendency to get worse.
[0015]
In order to compensate for the above disadvantages, for example, JP-A-1-306857 discloses a fluorine-containing silane coupling agent, a titanate coupling agent or C ₇ F ₁₅ A protective layer to which a compound such as NCO is added is disclosed in Japanese Patent Application Laid-Open No. 62-295066. A metal fine powder or a metal oxide fine powder whose dispersibility and moisture resistance are improved by water-repellent treatment in a binder resin. JP-A-2-50167 discloses a metal oxide fine powder whose surface is treated with a titanate coupling agent, a fluorine-containing silane coupling agent and acetoalkoxyaluminum diisopropylate in a binder resin. A protective layer in which is dispersed is disclosed.
[0016]
Further, examples in which a charge transport material having a hydroxy group as in the present invention is contained in a protective layer are disclosed in JP-A-10-228126 and JP-A-10-228127.
[0017]
However, even in these protective layers, in order to meet the demands for high durability and high image quality in recent years, protective layers such as various impacts on the surface, durability against the occurrence of wear and scratches, and toner releasability In the present situation, no satisfactory electrophotographic characteristics have been obtained.
[0018]
[Problems to be solved by the invention]
An object of the present invention is to have sufficient mechanical strength as a protective layer, and hardly increase the residual potential in a low-humidity environment. Also, an image blur in a high-humidity environment, a high-quality image without flow. It is an object to provide an electrophotographic photoreceptor capable of obtaining the above.
[0019]
Another object of the present invention is an electrophotographic photosensitive member having excellent releasability, surface properties having excellent durability against wear and scratches, and capable of maintaining high quality image quality. Is to provide.
[0020]
Still another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[0021]
[Means for Solving the Problems]
According to the present invention, in an electrophotographic photosensitive member having at least a photosensitive layer and a protective layer on a conductive support, the protective layer comprises a curable acrylic resin, and at least a substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group. An electrophotographic photoreceptor comprising a charge transport material having one is provided.
[0022]
In addition, according to the present invention, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member are provided.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0024]
As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by using an electrophotographic photosensitive member having a protective layer formed by combining a specific binder resin and a specific compound. It came to.
[0025]
That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer and a protective layer on a conductive support, wherein the protective layer contains a curable acrylic resin and has a substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group. It comprises an electrophotographic photosensitive member characterized by containing a charge transport material having at least one.
[0026]
These have the effect of quickly dissipating charges accumulated at the interface between the charge transport layer and the protective layer, etc., with respect to the curable acrylic resin layer obtained mainly by three-dimensionally crosslinking the polyfunctional acrylic monomer. By containing a charge transport material having a specific structure, the residual potential of the electrophotographic photosensitive member having the protective layer is lowered without impairing the mechanical strength of the protective layer, and the protective layer can be used in any environment. Provided is an electrophotographic photosensitive member capable of obtaining a high-quality image with little fluctuation in volume resistivity of the film, little increase in residual potential under low humidity, and no image blur or flow under high humidity. It is.
[0027]
Although the reason why the volume resistivity fluctuation as described above is small is not clear, by containing the charge transport material of the present invention in the curable acrylic resin together, the moisture adsorption site of the acrylic resin is transported by charge. It seems that the fluctuation of volume resistivity is reduced by suppressing the adsorption of moisture from the outside due to the action of blocking the hydroxy structure of the material.
[0028]
The curable acrylic resin that is a binder resin used for the protective layer in the present invention is formed from a curable acrylic monomer or oligomer. The acrylic monomer is a compound having a reactive acrylic group or methacrylic group, and in particular, the monomer that undergoes three-dimensional crosslinking polymerization like the protective layer of the present invention is a reactive acrylic group or methacrylic group in the molecule. It is preferable that the number of etc. is two or more. In addition, when using a compound having only one reactive acrylic group or methacrylic group in the monomer, it is preferable to use a mixture with a monomer having two or more reactive acrylic groups or methacrylic groups. .
[0029]
As the acrylic resin used in the present invention, any known acrylic resin may be used. The protective layer of the present invention is formed by coating and forming a coating solution obtained by dissolving and diluting a curable acrylic monomer or oligomer with a solvent or the like on the photosensitive layer. Form. As a form of curing polymerization, polymerization only by heat, or coexisting with heat and a photoinitiator, coating a protective layer and then heating or irradiating with light causes a polymerization reaction to generate a polymer cured layer.
[0030]
The charge transport material having at least one substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group of the present invention may have any structure, and is particularly represented by any one of the following formulas (1) to (3). Preferably, the compound has a specific structure, and is preferably composed of an electrophotographic photoreceptor having a protective layer containing at least one of these.
[0031]
[Formula 4]

[0032]
Where R ₁ , R ₂ And R _Three Represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and α, β and γ each have a halogen atom as a substituent, an alkyl group which may have a substituent, or a substituent. An alkenyl group which may have an aryl group which may have a substituent, or a benzene ring which may have one or more heterocyclic groups which may have a substituent, a, b and d are 0; Or 1 and m and n are 0 or 1.
[0033]
[Chemical formula 5]

[0034]
Where R _Four And R _Five Represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and δ and ε each have a halogen atom as a substituent, an alkyl group which may have a substituent, or a substituent. An alkenyl group which may have an aryl group which may have a substituent or a benzene ring which may have one or more heterocyclic groups which may have a substituent, and e and f are 0 or 1 . p is 0 or 1. Z ₁ And Z ₂ Are a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, respectively. May be shown together to form a ring.
[0035]
[Chemical 6]

[0036]
Where R ₆ , R ₇ , R ₈ And R ₉ Represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and ζ, η, θ and ι are a halogen atom as a substituent, an alkyl group which may have a substituent, and a substituent. An benzene ring that may have one or more heterocyclic groups that may have one or more heterocyclic groups that may have an alkoxy group that may have, an aryl group that may have a substituent, or a substituent; And k is 0 or 1, and q, r, and s are 0 or 1. Z _Three And Z _Four Are a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, respectively. May be shown together to form a ring.
[0037]
The structures of substituents and the like in the above formulas (1) to (3) will be described in detail below.
[0038]
Where R ₁ ~ R ₉ Represents a divalent hydrocarbon group such as a methylene group, an ethylene group, a propylene group and a butylene, which may be branched, each having 1 to 8 carbon atoms.
[0039]
In the formula, the substituent that the benzene ring represented by α, β, γ, δ, ε, ζ, η, θ, and ι may have a halogen atom such as fluorine, chlorine, bromine, and iodine, or a substituent. Alkyl groups such as methyl group, ethyl group, propyl group and butyl group which may have, alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group which may have substituents, and substituents An aryl group such as a phenyl group, a naphthyl group, an anthryl group and a pyrenyl group which may be substituted, or a heterocyclic group such as a pyridyl group, a thienyl group, a furyl group and a quinolyl group which may have a substituent is shown.
[0040]
Where Z ₁ ~ Z _Four Is a halogen atom such as fluorine, chlorine, bromine and iodine, an alkyl group such as an optionally substituted methyl group, ethyl group, propyl group and butyl group, an optionally substituted methoxy group and an ethoxy group , An alkoxy group such as a propoxy group and a butoxy group, an aryl group such as a phenyl group which may have a substituent, a naphthyl group, an anthryl group and a pyrenyl group, or a pyridyl group which may have a substituent, a thienyl group, Heterocyclic groups such as a furyl group and a quinolyl group are shown. Z ₁ And Z ₂ And Z _Three And Z _Four May form a cyclic structure such as a fluorene skeleton or a dihydrophenanthrene skeleton through a biphenyl skeleton to which they are bonded together.
[0041]
Examples of the substituent that may be contained in the formulas (1) to (3) include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, aralkyl groups such as benzyl group, phenethyl group and naphthylmethyl group, phenyl Groups, naphthyl groups, anthryl groups, pyrenyl groups, fluorenyl groups, carbazolyl groups, aromatic ring groups such as dibenzofuryl groups and dibenzothiophenyl groups, alkoxy groups such as methoxy groups, ethoxy groups and propoxy groups, phenoxy groups and naphthoxy groups Aryloxy groups, halogen atoms such as fluorine, chlorine, bromine and iodine, nitro groups and cyano groups.
[0042]
However, in the present invention, any structure may be used as long as it is a charge transport material having at least one substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group, and the structure represented by the formulas (1) to (3) It is not limited.
[0043]
The charge transport material having a specific structure represented by the formulas (1) to (3) used in the present invention is uniformly dissolved or dispersed in a coating solution for producing a protective layer, and is formed by coating. The mixing ratio of the charge transporting material of the formulas (1) to (3) and the curable acrylic resin binder is preferably a mass ratio of charge transporting material / acrylic resin binder = 0.1 / 10-20 / 10, particularly 0. It is preferably 5/10 to 10/10. If the charge transport material is too small relative to the acrylic resin binder, the effect of lowering the residual potential is reduced, and if it is too much, the strength of the protective layer may be weakened.
[0044]
Specific examples of the charge transport material having at least one substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group used in the present invention are illustrated below, but the present invention is not limited only to these compounds. .
[0045]
[Chemical 7]

[0046]
[Chemical 8]

[0047]
[Chemical 9]

[0048]
[Chemical Formula 10]

[0049]
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[0050]
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[0051]
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[0052]
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[0053]
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[0054]
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[0055]
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[0056]
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[0057]
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[0058]
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[0059]
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[0060]
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[0061]
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[0062]
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[0063]
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[0064]
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[0065]
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[0066]
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[0067]
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[0068]
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[0069]
The protective layer of the electrophotographic photoreceptor of the present invention contains a curable acrylic resin and a charge transport material having at least one substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group, but further contains conductive particles. As a result, the residual potential of the electrophotographic photosensitive member can be reduced at a high level.
[0070]
Examples of the conductive particles used in the protective layer in the present invention include metals, metal oxides, and carbon black. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, and zirconium oxide doped with antimony. . These can be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion.
[0071]
Moreover, in this invention, it is preferable to use a metal oxide from the point of transparency among the electroconductive particle mentioned above. Further, among these metal oxides, it is particularly preferable to use tin oxide. This tin oxide may be surface-treated as described later for the purpose of improving dispersibility and liquid stability, and may be doped with antimony or tantalum for the purpose of improving resistance controllability.
[0072]
The average particle size of the conductive particles used in the present invention is preferably 0.3 μm or less, particularly preferably 0.1 μm or less, from the viewpoint of the transparency of the protective layer.
[0073]
The ratio of the resin and the conductive particles is a value that directly determines the volume resistivity of the protective layer, and the volume resistivity of the protective layer is 10 ^Ten -10 ¹⁵ It is preferable to set so as to be in the range of Ω · cm. ¹¹ -10 ¹⁴ It is preferable to use Ω · cm.
[0074]
Since the film strength becomes weaker as the amount of the conductive particles increases, the amount of the conductive particles is preferably reduced within a range where the volume resistance and the residual potential of the protective layer can be tolerated.
[0075]
Furthermore, for the purpose of imparting lubricity to the surface of the protective layer, at least one of fluorine atom-containing resin particles, silica particles, silicone resin particles, and alumina particles may be mixed and used.
[0076]
Examples of the fluorine atom-containing resin particles used in the present invention include ethylene tetrafluoride, ethylene trifluoride chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin and One or two or more of these copolymers are preferably selected as appropriate, and ethylene tetrafluoride resin and vinylidene fluoride resin are particularly preferable. The molecular weight of the resin particles and the particle size of the particles can be appropriately selected and are not particularly limited.
[0077]
Further, fluorine atom-containing compounds and siloxane compounds can be contained together for the purpose of stabilizing the dispersibility of the lubricating particles, improving the slipperiness of the surface, and improving the leveling property of the coated surface.
[0078]
In order to prevent the lubricating particles from coagulating with the conductive particles in the resin solution, a fluorine atom-containing compound is added when the conductive particles are dispersed, or the surface of the conductive particles is coated with a fluorine atom-containing compound. It is good to process. Dispersibility and dispersion stability of conductive particles and fluorine atom-containing resin particles in the resin solution compared to the case without fluorine atom-containing compounds by adding fluorine atom-containing compounds or surface treatment of conductive particles Has improved dramatically. Also, secondary particles of dispersed particles are formed by dispersing fluorine atom-containing resin particles in a liquid in which conductive particles are dispersed by adding a fluorine atom-containing compound or in a liquid in which conductive particles subjected to surface treatment are dispersed. Thus, a coating solution having a very stable dispersibility can be obtained over time.
[0079]
Examples of the fluorine atom-containing compound in the present invention include a fluorine-containing silane coupling agent, a fluorine-modified silicone oil, and a fluorine-based surfactant. Although the preferable compound example of these compounds is given in Table 1-Table 3, this invention is not limited to these compounds.
[0080]
[Table 1]

[0081]
[Table 2]

[0082]
[Table 3]

[0083]
As a surface treatment method for the conductive particles, the conductive particles and the surface treatment agent are mixed and dispersed in an appropriate solvent, and the surface treatment agent is adhered to the surface of the conductive particles. As a dispersion method, a normal dispersion means such as a ball mill or a sand mill can be used. Next, the solvent may be removed from the dispersion and fixed to the surface of the conductive particles. Moreover, you may heat-process further after this as needed. Further, a catalyst for promoting the reaction can be added to the treatment liquid. Furthermore, if necessary, the conductive particles after the surface treatment can be further pulverized.
[0084]
The ratio of the fluorine atom-containing compound to the conductive particles is also affected by the particle size, shape, surface area, and the like of the particles, but is preferably 1 to 65% by mass with respect to the total mass of the surface-treated conductive particles, particularly 1 -50 mass% is preferable.
[0085]
Furthermore, in the present invention, in order to obtain a more environmentally stable protective layer, a siloxane compound represented by the following formula (4) is added at the time of dispersing the conductive particles, or a conductive material that has been previously surface-treated. By mixing the particles, a protective layer that is more excellent in environmental stability can be obtained.
[0086]
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[0087]
In the formula, A is a hydrogen atom or a methyl group, the proportion of hydrogen atoms in all of A is in the range of 0.1 to 50%, and n is an integer of 0 or more.
[0088]
By dispersing the coating liquid in which the siloxane compound is dispersed or the conductive fine particles obtained by surface-treating the coating liquid in a binder resin dissolved in a solvent, there is no formation of secondary particles of dispersed particles over time. In addition, a stable coating solution having good dispersibility was obtained, and the protective layer formed from this coating solution was highly transparent, and a film having particularly excellent environmental resistance was obtained.
[0089]
The molecular weight of the siloxane compound represented by the formula (4) is not particularly limited. However, in the case of surface treatment, it is better that the viscosity is not too high for ease of treatment, and the weight average molecular weight is several hundred to several. Ten thousand is appropriate.
[0090]
There are two types of surface treatment methods, wet and dry. In the wet process, conductive particles are dispersed in a solvent with the siloxane compound represented by the formula (4), and the siloxane compound is adhered to the particle surface. As a dispersing means, a general dispersing means such as a ball mill or a sand mill can be used. Next, this dispersion solution is fixed to the surface of the conductive particles. In this heat treatment, Si—H bonds in the siloxane are oxidized by hydrogen atoms by oxygen in the air during the heat treatment process, and new siloxane bonds are formed. As a result, siloxane develops to a three-dimensional structure, and the surface of the conductive particles is covered with this network structure. As described above, the surface treatment is completed by fixing the siloxane compound to the surface of the conductive particles. However, if necessary, the treated fine particles may be pulverized. In the dry treatment, the siloxane compound and the conductive particles are mixed and kneaded without using a solvent, and the siloxane compound is adhered to the particle surface. Thereafter, the surface treatment is completed by performing a heat treatment or a pulverization treatment in the same manner as the wet treatment.
[0091]
As a solvent for dispersing the coating liquid for the protective layer, the acrylic resin monomer and the like are well dissolved, the charge transporting materials represented by the formulas (1) to (3) are also well dissolved, and when conductive particles are used, the dispersion is performed. When using fluorine atom-containing compounds, fluorine atom-containing resin particles, and siloxane compounds, their compatibility and processability are good, and the charge transport layer in contact with the coating liquid of the protective layer is further adversely affected. No solvent is preferred.
[0092]
Therefore, the solvent includes alcohols such as methanol, ethanol and 2-propanol, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, ethers such as tetrahydrofuran and dioxane, and aromatics such as toluene and xylene. Group hydrocarbons or halogenated hydrocarbons such as chlorobenzene and dichloromethane may be used, and these may be used in combination. Among these, the most preferred solvents are alcohols such as methanol, ethanol and 2-propanol.
[0093]
As a method for applying the protective layer of the present invention, general coating methods such as a dip coating method, a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, and a blade coating method can be used.
[0094]
If the thickness of the protective layer of the present invention is too thin, the durability of the electrophotographic photosensitive member is impaired, and if it is too thick, the residual potential due to the provision of the protective layer increases. Specifically, a range of 0.1 μm to 10 μm is preferable, and a range of 0.5 μm to 7 μm is particularly preferable.
[0095]
In the present invention, an additive for an antioxidant may be added to the protective layer for the purpose of preventing deterioration of the surface layer due to adhesion of active substances such as ozone and NOx generated during charging.
[0096]
Next, the photosensitive layer will be described below.
[0097]
The electrophotographic photoreceptor of the present invention preferably has mainly a laminated structure. In the electrophotographic photosensitive member of FIG. 1A, a charge generation layer 3 and a charge transport layer 2 are provided in this order on a conductive support 4, and a protective layer 1 is further provided on the outermost surface. Further, as shown in FIGS. 1B and 1C, a binder layer 5 and an undercoat layer 6 for the purpose of preventing interference fringes may be provided between the conductive support and the charge generation layer. .
[0098]
As the conductive support 4, the support itself can be conductive, for example, a metal such as aluminum, aluminum alloy, and stainless steel. In addition, aluminum, aluminum alloy, indium oxide-tin oxide alloy, or the like can be used. The conductive support, plastic, and conductive fine particles (for example, carbon black, tin oxide, titanium oxide, silver particles, etc.) having a layer formed by vacuum deposition and impregnated in plastic or paper with an appropriate binder. A plastic having a conductive binder can be used.
[0099]
In addition, a binder layer (adhesive layer) having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The binder layer is used to improve the adhesion of the photosensitive layer, improve coating properties, protect the support, cover defects on the support, improve charge injection from the support, and protect the photosensitive layer from electrical breakdown. It is formed. The binder layer can be formed of casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin, aluminum oxide, or the like. The film thickness of the binder layer is preferably 5 μm or less, and particularly preferably 0.1 to 3 μm.
[0100]
Examples of the charge generating material used in the present invention include (1) azo pigments such as monoazo, disazo and trisazo, (2) phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, and (3) indigo materials such as indigo and thioindigo. Pigments, (4) perylene pigments such as perylene anhydride and perylene imide, (5) polycyclic quinone pigments such as anthraquinone and pyrenequinone, (6) squarylium dyes, (7) pyrylium salts and thiapyrylium salts, ( 8) Triphenylmethane dye, (9) inorganic substances such as selenium, selenium-tellurium and amorphous silicon, (10) quinacridone pigment, (11) azulenium salt pigment, (12) cyanine dye, (13) xanthene dye, 14) quinoneimine dye, (15) styryl dye, (16) potassium sulfide Miumu and (17) zinc oxide.
[0101]
Examples of the binder resin used for the charge generation layer include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, Examples include, but are not limited to, silicone resins, polysulfone resins, styrene-butadiene copolymer resins, alkyd resins, epoxy resins, urea resins, and vinyl chloride-vinyl acetate copolymer resins. These may be used alone, as a mixture or as a copolymer polymer, or one or more of them may be used.
[0102]
The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the resin and charge generation material used, and examples of the organic solvent include alcohols, sulfoxides, ketones, ethers and esters. Aliphatic halogenated hydrocarbons or aromatic compounds can be used.
[0103]
The charge generation layer 3 is sufficiently dispersed by coating the charge generation material with 0.3 to 4 times the amount of binder resin and solvent by a method such as a homogenizer, ultrasonic wave, ball mill, sand mill, attritor or roll mill. , Dried and formed. The thickness is preferably 5 μm or less, and particularly preferably in the range of 0.01 to 1 μm.
[0104]
In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and known charge generating materials can be added to the charge generation layer as necessary.
[0105]
The charge transport materials used include various triarylamine compounds, various hydrazone compounds, various styryl compounds, various stilbene compounds, various pyrazoline compounds, various oxazole compounds, various thiazole compounds, and various triarylmethane compounds. Compounds and the like.
[0106]
Examples of the binder resin used to form the charge transport layer 2 include acrylic resin, styrene resin, polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin, alkyd resin, and unsaturated resin. A resin selected from is preferred. Particularly preferred resins include polymethyl methacrylate, polystyrene, styrene-acrylonitrile copolymer, polycarbonate resin and diallyl phthalate resin.
[0107]
The charge transport layer 2 is generally formed by dissolving the charge transport material and the binder resin in a solvent and applying them. The mixing ratio of the charge transport material and the binder resin is about 2: 1 to 1: 2. Solvents include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, and chlorinated hydrocarbons such as chlorobenzene, chloroform and carbon tetrachloride. It is done. When applying this solution, for example, a coating method such as a dip coating method, a spray coating method and a spinner coating method can be used, and drying is preferably 10 ° C to 200 ° C, more preferably 20 ° C to 150 ° C. The temperature is in the range of 5 minutes to 5 hours, and more preferably 10 minutes to 2 hours.
[0108]
The charge transport layer is electrically connected to the above-described charge generation layer, receives charge carriers injected from the charge generation layer in the presence of an electric field, and transports these charge carriers to the interface with the protective layer. It has a function to do. Since this charge transport layer has a limit for transporting charge carriers, the film thickness cannot be increased more than necessary, but it is preferably 5 to 40 μm, particularly preferably 7 to 30 μm.
[0109]
Furthermore, an antioxidant, an ultraviolet absorber, a plasticizer, and a known charge transport material can be added to the charge transport layer as necessary.
[0110]
In the present invention, the protective layer is coated on the charge transport layer and cured to form a film.
[0111]
FIG. 2 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.
[0112]
In FIG. 2, reference numeral 11 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 12 in the direction of an arrow at a predetermined peripheral speed. In the rotation process, the electrophotographic photosensitive member 11 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the primary charging unit 13, and then from an exposure unit (not shown) such as slit exposure or laser beam scanning exposure. The exposure light 14 whose intensity is modulated corresponding to the time-series electric digital image signal of the target image information to be output is received. In this way, electrostatic latent images corresponding to target image information are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 11.
[0113]
The formed electrostatic latent image is then developed with toner by the developing means 15 and taken out from a paper feeding unit (not shown) between the electrophotographic photosensitive member 11 and the transfer means 16 in synchronization with the rotation of the electrophotographic photosensitive member 11. The toner image formed and supported on the surface of the electrophotographic photosensitive member 11 is sequentially transferred by the transfer unit 16 to the transferred transfer material 17.
[0114]
The transfer material 17 that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member, introduced into the image fixing means 18, and subjected to image fixing to be printed out as an image formed product (print, copy). .
[0115]
After the image is transferred, the surface of the electrophotographic photosensitive member 11 is cleaned by removing the transfer residual toner by the cleaning unit 19, and is further subjected to charge removal processing by the pre-exposure light 20 from the pre-exposure unit (not shown). Used repeatedly for image formation. When the primary charging unit 13 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.
[0116]
In the present invention, a plurality of components such as the electrophotographic photosensitive member 11, the primary charging unit 13, the developing unit 15 and the cleaning unit 19 are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 13, the developing unit 15, and the cleaning unit 19 is integrally supported together with the electrophotographic photosensitive member 11 to form a cartridge, and is attached to and detached from the apparatus main body using a guide unit 22 such as a rail of the apparatus main body. A flexible process cartridge 21 can be obtained.
[0117]
Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 14 is a reflected light or transmitted light from a document, or a signal is read by a document by a sensor, and a laser beam scanning performed according to this signal is performed. The light emitted by driving the LED array or the liquid crystal shutter array.
[0118]
The electrophotographic photosensitive member of the present invention can be used not only for electrophotographic copying machines but also widely applicable to electrophotographic application fields such as laser beam printers, CRT printers, LED printers, FAX, liquid crystal printers, and laser plate making. It is.
[0119]
【Example】
Hereinafter, the present invention will be described in more detail with reference to specific examples. However, embodiments of the present invention are not limited to these. In the examples, “part” means “part by mass”.
[0120]
Example 1
Using a 30 mm × 260.5 mm aluminum cylinder (JIS A3003 aluminum alloy) as a support, a 5 mass% methanol solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) is applied thereon by a dipping method and dried with hot air. An undercoat layer having a thickness of 0.5 μm was formed.
[0121]
Next, as a charge generation material, a crystal type having strong peaks at 9.6 ° and 27.2 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction represented by the following formula (5): 4 parts of oxytitanium phthalocyanine pigment,
[0122]
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2 parts of polyvinyl butyral resin BX-1 (manufactured by Sekisui Chemical Co., Ltd.) and 110 parts of cyclohexanone were dispersed in a sand mill for 4.5 hours using φ1 mm glass beads. Then, it diluted with 130 parts of ethyl acetate, and was set as the coating liquid for charge generation layers. The coating solution was applied onto the previous undercoat layer by an immersion method to form a charge generation layer having a thickness of 0.18 μm.
[0123]
Next, 10 parts of the charge transport material represented by the following formula (6)
[0124]
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And 10 parts of bisphenol Z-type polycarbonate (trade name: Z-200, manufactured by Mitsubishi Gas Chemical) was dissolved in 60 parts of monochlorobenzene / 20 parts of dichloromethane. This coating solution was dip-coated on the charge generation layer and dried with hot air at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm.
[0125]
Next, as a protective layer, 30 parts of a curable acrylic resin represented by the following formula (7) and 5.2 parts of 2-methylthioxanthone as a photopolymerization initiator are dissolved, and further a compound as a charge transport material having a hydroxyalkyl group Example No. 21 parts of 1-25 were dissolved to prepare a protective layer coating solution.
[0126]
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[0127]
This coating solution is dip coated on the charge transport layer to form a film, followed by 800 mW / cm with a high pressure mercury lamp. ² The film was photocured for 60 seconds at a light intensity of 1, and then dried with hot air at 120 ° C. for 2 hours to form a protective layer having a thickness of 3 μm, and an electrophotographic photoreceptor was prepared and evaluated. The dispersibility of the protective layer coating solution was good, and the prepared protective layer was a uniform film without unevenness.
[0128]
The volume resistivity of the protective layer is measured by forming a comb-shaped electrode having a gap of 180 μm on a polyethylene terephthalate film by gold vapor deposition, applying a protective layer coating solution thereon, and curing conditions, film thickness, etc. A sample was prepared in the same manner as in the preparation of the photoconductor.
[0129]
The volume resistivity was measured by applying 100 V to the sample using a PA meter 4140B manufactured by Bullet Packard. The measurement environment was measured under three environments of temperature / humidity of 23 ° C./50% RH, 23 ° C./5% RH, and 30 ° C./80% RH.
[0130]
The hardness of the protective layer was measured using a hardness meter (H100VP-HCU) manufactured by FISCHER, Germany. The hardness by this measurement is determined as follows.
[0131]
That is, a diamond indenter with a face angle of 130 ° at the tip of a quadrangular pyramid is used to apply a load to the protective layer film to 1 μm. From the surface area of the indentation calculated from the geometric shape of the indenter and the load at that time, Asking;
Universal hardness value HU (N / mm ² ) = Load (N) / Indentation surface area under load (mm ² )
[0132]
The hardness of the protective layer in the examples is measured by applying a protective layer coating solution on a glass plate and curing conditions in the same manner as in the preparation of the electrophotographic photoreceptor, and coating this protective layer film 3 to 4 times. Then, the film thickness was set to about 10 μm to obtain a hardness measurement sample.
[0133]
For the evaluation of the electrophotographic characteristics, Canon Inc. LBP-NX was used. As an evaluation, the initial transfer efficiency, the measurement of the amount of scraping by durability of 3000 sheets, and the image characteristics under a 30 ° C./80% environment were observed. Furthermore, the residual potential (Vr) was measured at a position 0.2 seconds after strong exposure using a drum tester manufactured by Gentec in an environment of 23 ° C./5% RH.
[0134]
Table 4 shows the results of resistance measurement and film hardness, and Table 5 shows the results of electrophotographic characteristics.
[0135]
(Examples 2 to 7)
Instead of the charge transport material (Compound Example No. 1-25) having a hydroxyalkyl group used in Example 1, a charge having at least one substituent selected from hydroxyalkyl groups and hydroxyalkoxy groups shown in Table 4 An electrophotographic photoreceptor and the like were prepared and evaluated in the same manner as in Example 1 except that the transport material was used. The results are similarly shown in Tables 4 and 5.
[0136]
(Example 8)
Up to the charge transport layer was produced in the same manner as in Example 1.
[0137]
Next, as a protective layer, 100 parts of antimony-doped tin oxide ultrafine particles were surface-treated with 7 parts of a fluorine atom-containing compound (trade name: LS-1090, manufactured by Shin-Etsu Silicone Co., Ltd.) represented by the following formula (8) ( (Treatment amount 7%) 35 parts of treated tin oxide fine particles and
[0138]
Embedded image

150 parts of ethanol was dispersed in a sand mill for 66 hours, and further 20 parts of polytetrafluoroethylene fine particles (average particle size 0.18 μm) were added, followed by further dispersion in a sand mill for 12 hours. Thereafter, 31 parts of the curable acrylic resin used in Example 1 and 5.4 parts of 2-methylthioxanthone were dissolved as the resin component, and Compound Example No. 1 was used as a charge transport material having a hydroxyalkyl group. 15 parts of 1-22 was dissolved to obtain a protective layer coating solution.
[0139]
Using this coating solution, a film was formed on the previous charge transport layer by dip coating, and then 800 mW / cm with a high-pressure mercury lamp. ² Then, photocuring was performed for 60 seconds at a light intensity of, followed by hot-air drying at 120 ° C. for 2 hours to form a protective layer having a thickness of 3 μm. The dispersibility of the protective layer coating solution was good, and the prepared protective layer was a uniform film without unevenness. Thereafter, the volume resistivity and environmental variation of the protective layer, the hardness, durability, and electrophotographic characteristics of the protective layer were evaluated in the same manner as in Example 1. The results are similarly shown in Tables 4 and 5.
[0140]
(Examples 9 to 14)
Instead of the charge transport material (Compound Example No. 1-22) having a hydroxyalkyl group used in Example 8, a charge having at least one substituent selected from hydroxyalkyl groups and hydroxyalkoxy groups shown in Table 4 An electrophotographic photoreceptor and the like were prepared and evaluated in the same manner as in Example 8 except that the transport material was used. The results are similarly shown in Tables 4 and 5.
[0141]
(Examples 15 to 17)
In Examples 8, 10 and 12, the amount of antimony-doped tin oxide fine particles surface-treated with the compound represented by the formula (8) (treatment amount 7%) was reduced to 20 parts, and methyl hydrogen silicone oil (trade name: KF99, Except for preparing a coating liquid by further adding and dispersing 15 parts of antimony-doped tin oxide fine particles treated with Shin-Etsu Silicone Co., Ltd. (treatment amount 20%), in exactly the same manner as in Examples 8, 10 and 12. An electrophotographic photoreceptor was prepared and evaluated. The results are similarly shown in Tables 4 and 5.
[0142]
(Examples 18 to 20)
In Examples 8, 10, and 12, in place of the antimony-doped tin oxide fine particles surface-treated with the compound represented by the formula (8), antimony-doped tin oxide fine particles before the surface treatment (trade name: T-1, Except that 35 parts of Mitsubishi Materials Co., Ltd.) and 3.5 parts of the fluorine atom-containing compound represented by the above formula (8) (trade name: LS-1090, Shin-Etsu Silicone Co., Ltd.) were added and dispersed. An electrophotographic photoreceptor and the like were prepared and evaluated in exactly the same manner as in Examples 8, 10 and 12. The results are similarly shown in Tables 4 and 5.
[0143]
(Examples 21 to 23)
In Examples 18 to 20, electrophotography was carried out in the same manner as in Examples 18 to 20, except that 1.5 parts of methyl hydrogen silicone oil (trade name: KF99, manufactured by Shin-Etsu Silicone Co., Ltd.) was further added and dispersed. Photoconductors and the like were prepared and evaluated. The results are similarly shown in Tables 4 and 5.
[0144]
(Example 24)
Up to the charge transport layer was produced in the same manner as in Example 1.
[0145]
Next, as a protective layer, 35 parts of antimony-doped tin oxide fine particles (trade name: T-1, manufactured by Mitsubishi Materials Corporation) and 150 parts of toluene are dispersed in a sand mill for 48 hours, and then as a resin component 31 parts of the curable acrylic resin used in Example 1 and 5.4 parts of 2-methylthioxanthone as a photopolymerization initiator are dissolved, and further, Compound Example No. 1 is used as a charge transport material having a hydroxyalkyl group. 15 parts of 3-2 was dissolved and diluted by adding 210 parts of toluene / 160 parts of acetone to obtain a protective layer coating solution. Using this coating solution, a film was formed on the previous charge transport layer by spray coating, and then 800 mW / cm with a high-pressure mercury lamp. ² Then, photocuring was performed for 60 seconds at a light intensity of, followed by hot-air drying at 120 ° C. for 2 hours to form a protective layer having a thickness of 3 μm. The dispersibility of the protective layer coating solution was good, and the prepared protective layer was a uniform film without unevenness. Further, a resistance measurement sample and a hardness measurement sample were produced in the same manner as in Example 1, and evaluation was performed in the same manner as in Example 1. The results are similarly shown in Tables 4 and 5.
[0146]
(Examples 25 and 26)
Instead of the charge transport material (Compound Example No. 3-2) having a hydroxyalkyl group used in Example 24, a charge having at least one substituent selected from hydroxyalkyl groups and hydroxyalkoxy groups shown in Table 4 An electrophotographic photoreceptor and the like were prepared and evaluated in the same manner as in Example 24 except that the transport material was used. The results are similarly shown in Tables 4 and 5.
[0147]
(Comparative Example 1)
In Example 1, an electrophotographic photosensitive member and the like were prepared and evaluated in the same manner as in Example 1 except that no charge transport material was added. The results are similarly shown in Tables 4 and 5.
[0148]
(Comparative Example 2)
In Example 8, an electrophotographic photoreceptor and the like were prepared and evaluated in the same manner as in Example 8 except that the charge transport material was not added. The results are similarly shown in Tables 4 and 5.
[0149]
(Comparative Examples 3-6)
Instead of the charge transport material (Compound Example No. 1-22) having a hydroxyalkyl group used in Example 8, it was changed to Comparative Compounds 1 to 4 represented by the following formula in the same manner as in Example 8. An electrophotographic photosensitive member was prepared and evaluated. The results are similarly shown in Tables 4 and 5.
[0150]
Embedded image

[0151]
(Comparative Example 7)
Instead of the protective layer in Example 1, 35 parts of the treated tin oxide fine particles used in Example 8 and 150 parts of 1,4-dioxane were dispersed in a sand mill for 66 hours, and polytetrafluoroethylene was further dispersed. 20 parts of fine particles (average particle size 0.18 μm) were added, and dispersion was further performed by a sand mill for 12 hours. Thereafter, 31 parts of PMMA (trade name: J-899, manufactured by Hoshiko Chemical Co., Ltd.) is dissolved in place of the curable acrylic resin as a resin component, and Compound No. 1 is used as a charge transport material having a hydroxyalkyl group. 15 parts of 1-22 was dissolved, further dispersed with a sand mill for 1 hour, and diluted with 370 parts of 1,4-dioxane to obtain a coating solution for a protective layer. Using this coating solution, a film is formed on the charge transport layer by spray coating, and then dried with hot air at 100 ° C. for 30 minutes to produce an electrophotographic photoreceptor having a protective layer with a thickness of 3 μm. ,evaluated. The results are similarly shown in Tables 4 and 5.
[0152]
(Comparative Example 8)
In Example 1, an electrophotographic photoreceptor was prepared and evaluated in exactly the same manner as in Example 1 except that the protective layer was not applied. The results are similarly shown in Tables 4 and 5.
[0153]
[Table 4]

[0154]
[Table 5]

[0155]
As shown in Tables 4 and 5, by using the electrophotographic photoreceptor having the protective layer of the present invention, the residual potential is excellent even in a low humidity environment where the resistance of the protective layer is excellent in environmental stability and the residual potential is most severely increased. The film was low, the transfer efficiency was high, the image was not transferred under high humidity, the film strength was maintained, the scraping amount was maintained, the durability was high, the stability was stable, and a good image could be obtained.
[0156]
【The invention's effect】
As described above, as in the present invention, by using the electrophotographic photosensitive member of the present invention, the environmental stability of the resistance of the protective layer is excellent, and the residual potential is low even in a low humidity environment where the increase in the residual potential is the most severe, Providing an electrophotographic photoreceptor that has high transfer efficiency, no image flow under high humidity, maintains film strength, maintains scraping amount, is highly durable, highly stable, and can provide good images. It became possible to do.
[0157]
In addition, in the process cartridge and the electrophotographic apparatus having the electrophotographic photosensitive member, the same remarkable effect could be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a layer structure of an electrophotographic photosensitive member of the present invention.
FIG. 2 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention.
[Explanation of symbols]
1 Protective layer
2 Charge transport layer
3 Charge generation layer
4 Conductive support
5 binding layers
6 Underlayer
11 Electrophotographic photoreceptor
12 axes
13 Charging means
14 Exposure light
15 Development means
16 Transfer means
17 Transfer material
18 Fixing means
19 Cleaning means
20 Pre-exposure light
21 Process cartridge
22 Guide means

Claims (9)

  In an electrophotographic photosensitive member having at least a photosensitive layer and a protective layer on a conductive support, the protective layer contains a curable acrylic resin and has at least one substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group. An electrophotographic photoreceptor comprising a charge transport material. The electrophotographic photosensitive member according to claim 1, wherein the charge transport material having at least one substituent selected from the hydroxyalkyl group and the hydroxyalkoxy group is a compound represented by any one of the following formulas (1) to (3). Body :

(In the formula, R ₁ , R ₂ and R ₃ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched; α, β and γ represent a halogen atom or a substituent as a substituent, respectively. It may have one or more alkyl groups that may have, alkoxy groups that may have substituents, aryl groups that may have substituents, or heterocyclic groups that may have substituents. A benzene ring, a, b and d are 0 or 1, and m and n are 0 or 1 .

(Wherein R ₄ and R ₅ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and δ and ε may each have a halogen atom or a substituent as a substituent. An alkyl group, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a benzene ring that may have one or more heterocyclic groups that may have a substituent; e and f are 0 or 1. p is 0 or 1. Z ₁ and Z ₂ are each a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, An aryl group which may have a substituent or a heterocyclic group which may have a substituent, and may form a ring together) ,

(Wherein R ₆ , R ₇ , R ₈ and R ₉ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and ζ, η, θ and ι are each a halogen as a substituent. One or more atoms, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent Benzene ring which may have, g, h, j and k are 0 or 1, q, r and s are 0 or 1. Z ₃ and Z ₄ each have a halogen atom and a substituent. An alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent; Good) .   The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains conductive particles.   The electrophotographic photosensitive member according to claim 3, wherein the conductive particles are tin oxide that has been surface-treated or doped.   The electrophotographic photoreceptor according to claim 1, wherein the protective layer contains at least one of fluorine atom-containing resin particles, silica particles, silicone resin particles, and alumina particles.   The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains at least one of a fluorine atom-containing compound and a siloxane compound.   The electrophotographic photosensitive member according to claim 1, a charging means for charging the electrophotographic photosensitive member, a developing means for developing the electrophotographic photosensitive member on which an electrostatic latent image is formed, and a transfer step. A process cartridge which is integrally supported together with at least one means selected from the group consisting of cleaning means for collecting toner remaining on a later electrophotographic photosensitive member, and is detachable from an electrophotographic apparatus main body.   7. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, An electrophotographic apparatus comprising: a developing unit that develops toner on an electrophotographic photosensitive member on which a latent image is formed; and a transfer unit that transfers a toner image on the electrophotographic photosensitive member onto a transfer material. An electrophotographic photosensitive member having at least a photosensitive layer and a protective layer on a conductive support, wherein the protective layer has two or more reactive acrylic groups or methacrylic groups on the photosensitive layer. Alternatively, the curable acrylic monomer or oligomer in a coating film containing an oligomer and at least one of the charge transport materials represented by the above formulas (1) to (3) is polymerized. Electrophotographic photoreceptor.

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