JP3865555B2 - Lubricity imparting member device and image forming apparatus using the same - Google Patents

Lubricity imparting member device and image forming apparatus using the same Download PDF

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JP3865555B2
JP3865555B2 JP36401399A JP36401399A JP3865555B2 JP 3865555 B2 JP3865555 B2 JP 3865555B2 JP 36401399 A JP36401399 A JP 36401399A JP 36401399 A JP36401399 A JP 36401399A JP 3865555 B2 JP3865555 B2 JP 3865555B2
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lubricity imparting
lubricity
imparting member
elastic member
photoreceptor
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JP2001183941A (en
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宏 永目
洋太 左近
成人 小島
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Ricoh Co Ltd
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Ricoh Co Ltd
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Description

【０００１】
【発明の属する技術分野】
本発明は、ファクシミリ、プリンター、電子写真複写機等の画像形成装置の感光体の高寿命化、並びに、画像品質の長期安定性を達成するための潤滑性付与部材装置とそれを用いた画像形成装置に関する。
【０００２】
【従来の技術】
電子写真法を用いたファクシミリ、プリンター、電子写真複写機等の画像形成装置では、感光体に対して順に帯電、像露光、現像、転写、クリーニング、除電の各工程を作用させ画像形成が行われる。感光体には、硫化カドミウム、セレン化カドミウム、アモルファスセレン、アモルファスシリコンなどが使用されてきたが、近年では作製が容易、高感度、低コスト、無公害等の多くのメリットを有する有機系感光体が主流に使用されている。
【０００３】
有機系感光体の構成材料には高抵抗で透明性が高く、極性依存性がない高硬度のポリカーボネート系樹脂材料（Ａ型ポリカ、Ｃ型ポリカ、Ｚ型ポリカなど）が一般的に使用されるが、この材料をバインダーとして感光層を構成した場合、ヌープ硬度が１０〜２０ｋｇ／ｍｍ2と低く、また引っ張り強度が小さいため、傷つきやすく、摩耗しやすい。さらに、感光層面には帯電時に使用される帯電装置から生じるコロナ生成物の他、トナー構成物、紙粉等が付着する為、解像性の低下、クリーニング性や、転写効率の低下などで、画像の均一化が損なわれやすい。
【０００４】
また、感光体とクリーニングブレード（ポリウレタンゴムが主に使用される）との組み合わせでは摩擦係数が極めて高くなるため、高周波音（ブレード鳴き）が発生しやすい等の問題があり、電気特性、光学特性などの諸特性を維持しながら、機械特性を向上させるのには限度があった。
そのため、潤滑剤の機能を有効に活用する方法が検討された。以下に潤滑剤を使用した改善方法についての幾つかの開示例を示す。
【０００５】
（１）特開昭５６−５１７６７号：
感光体表面に付着した汚染物質を排除し、良好な画像形成を維持し続ける手段として、研磨剤と潤滑剤が交互に形成された像保持部材用潤滑研磨部材を設置し、感光体表面への研磨と潤滑剤付与を交互に行い、感光体に付着したトナー等を排除し、高画像品質を維持する。
【０００６】
（２）特開昭５６−１１３１８３号：
外表面に潤滑剤を保有している回転自在の円筒状潤滑剤補給部材を感光体に当接し、潤滑剤を感光体表面に供給することによって、画像品質の安定化を図る。
【０００７】
（３）特開平６−３４２２３６号：
固体疎水潤滑剤（ステアリン酸亜鉛などの固体）を帯電ローラーを介して、像坦持体（感光体）に円滑に安定供給し、クリーニング不良やフィルミングの発生を防止する。
【０００８】
（４）特開平８−２０２２２６号：
潤滑剤（ステアリン酸亜鉛など）の塗布量をコントロールしながら、像坦持体にブラシを介して常に適切な量を供給することによって、良好な画像形成の安定化を図る。
【０００９】
（５）特開平８−３０５２３３号：
トナー像を検知する手段を有する画像形成装置において、その検知内容に基づいて、トナークリーニングブラシの回転数をコントロールしながら、潤滑剤の感光体への供給量を調整し、高品質画像の安定化を図る。
【００１０】
（６）特開平１１−２９９４号：
デジタル方式の複写機とフッ素系樹脂粉体を分散した層を最表面に有する感光体との組み合わせで使用した場合、レーザー光照射の際のスポットによる散乱のために、解像度の劣化が起こる。この現象を回避するために、感光層上に形成したフッ素系樹脂粉体を分散した層の代わりに、トナーに対して離型性を示すフッ素樹脂を含有する材料、もしくはバインダー樹脂中に１０〜９０ｗｔ％分散された材料を感光体表層に塗布する。
【００１１】
これらの開示例は潤滑剤を感光体表層に供給（外添）することによって、画像品質の劣化防止、感光体の傷つき防止、耐摩耗性、転写効率（画像抜け防止）、クリーニング性の向上、画像流れ抑制、ブレードのめくれ防止、クリーニングブレードの延命等を行うものである。
【００１２】
【発明が解決しようとしている課題】
次に前記した開示例１〜６について内容及び問題点等について以下に説明する。
開示例１（特開昭５６−５１７６７号）は良好な画像形成を維持し続けること目的としたものである。巻き取り方式のベルトに酸化セリウム等の研磨剤層と四フッ化エチレンなどのフッ素系樹脂からなる潤滑剤層を交互に形成し、感光層上に形成された付着物を研磨剤で削った後、潤滑剤で表面性を修復しながら、感光層表面を清浄に保持する方法である。
４フッ化エチレン樹脂層を感光体に摺擦しながら付与する方式では、摩擦係数を低減化させる効率が大きいが、単に接触させただけでは硬度の低い有機感光体でなくとも簡単にスクラッチが入ってしまい、画像に筋が現れる様になる。また、更に研磨剤を使用するため、感光層表面が荒れやすく、不均一な削れ（例えばスクラッチ等）が起こり画像品質が低下させやすい。さらに必要以上に感光層を削ってしまうため、感光体の寿命が短くなるなどの問題を有する。
【００１３】
開示例２（特開昭５６−１１３１８３号）は細孔を有する布製のポーチなどに粉末状の潤滑剤を内在させ、その外表面に粉末状潤滑剤を保有させ、回転させながら常時感光体に潤滑剤を付与し、ブレードと感光体間の摩擦抵抗を低減化させることを目的とするものである。
回転体から粉末状潤滑剤を補給する場合、飛散はどうしても避けられず、周囲を汚しやすい。また塗布を均一に薄層でコントロールすることが難しく、摩擦係数にバラツキを生じ易い。塗布量が多すぎた場合には画像劣化にもつながる。
【００１４】
開示例３（特開平６−３４２２３６号）は潤滑剤を感光体の回転速度とは線速度を変えた帯電ロール（接触帯電部材）に一旦塗布し、それを感光体に再塗布し、感光体に潤滑効果を持たせるものである。此の方法は線速度を変えることによって塗布ムラをなくし、均一塗布を行う様にしたものであるが、ステアリン酸亜鉛の様な固形ワックスを使用しているため、塗布ムラを起こしやすく、帯電ローラーに塗布し使用する場合には帯電性が不均一になる危険性が大きい。この帯電不均一性の為に、ハーフトーン画像均一化が損なわれ、黒点、モヤムラ、地肌汚れなどの画像欠陥が起こりやすくなる。また、ステアリン酸亜鉛が過剰に付与された場合には、除去が容易ではなく、帯電装置からのコロナ生成物を巻き込み、解像性の低下を招きやすい。
【００１５】
開示例４（特開平８−２０２２２６号）はブラシに一旦塗布した潤滑剤を感光体に再塗布することによって、感光体の摩擦係数を低減する方法である。此の方法は帯電ロールを介して感光体に塗布する方式に比べ、ブラシを使用するため材質や穂の硬さ繊維系などで適正なブラシを選択することで、潤滑性を均一に塗布することが可能である。
潤滑性に優れたステアリン酸亜鉛などを塗布すると、耐摩耗性にも優れる。しかし、ステアリン酸亜鉛を極薄層に均質に塗布することのコントロールが難しく、感光体に付着すると厚くなり除去しにくいため、効果の持続性はあるが、帯電過程で生成されるコロナ生成物（画像流れの主原因）等の低抵抗物質、埃を巻き込みやすく、摩擦係数も徐々に増加する傾向がある。ステアリン酸亜鉛層が一層形成されると、掻き取り効果が低下するため、摩擦係数が低下し過ぎとなり、局部的な画像品質低下を起こす危険性が大きい。したがって、潤滑剤の塗布をコントロールする場合には、センサーのＳＮ比を大きくとり、さらに極薄層とするための正確な塗布制御機能が要求される。
【００１６】
開示例５（特開平８−３０５２３３号）はトナー像を検知する手段を有する画像形成装置において、その検知内容に基づいて、トナークリーニングブラシの回転数をコントロールしながら、潤滑剤の感光体への供給量を調整し、高品質画像の安定化を図るものである。
此の方式は画像からの判断により塗布量を自動コントロールするため、画像の大きな劣化が有った場合、或る程度の判定はできるが、局部的な劣化や、僅かな劣化では殆ど対応できない。また、ステアリン酸亜鉛が連続に塗布される場合には、コロナ生成物などの汚染物質を取り込み、次第に摩擦係数が上昇し、コロナ生成物の影響で画像流れも生じ易くなる。
【００１７】
開示例６（特開平１１−２９９４号）はフッ素樹脂分散層を感光体層上に形成した場合に、レーザー光が照射されると散乱が生じ、解像度が低下したり、転写効率が次第に低下する現象が有るため、フッ素樹脂分散層の代わりにフッ素樹脂の粉末を感光層上に塗布するか、粉末を分散した材料を感光体に押し当て塗布することでトナーに対する離型層を形成することによって問題点の改善を図るものである。このことにより転写効率の低下が抑制され、さらには感光層の摩耗も抑制される。
フッ素樹脂層を感光体表層に形成することで 摩擦係数が低下し、トナーに対し優れた離型性が発現され、感光体の摩耗も抑制される。但し、画像品質及び感光体を適正な状態に維持するためには適正な塗布条件で管理する必要がある。フッ素樹脂の必要以上の塗布は過大な低摩耗化を起こし、画像流れの原因になる。また、感光層の摩擦係数が低下することで、感光層の膜厚減少が抑制されるが、反面クリーニングブレードや、現像剤の滑りが生じ、画像濃度が大きく低下したり、感光体にトナー固着が起こり、画像品質の低下の要因ともなる。粉体状のフッ素樹脂を感光体に塗布した後、ブレードでならす様な方式では、摩擦係数に偏りを生じたり、局部的に粉体のまま固着する現象が起こり、逆に画像品質を乱すことが起こる。また、フッ素樹脂粉末を分散した部材で離型層を形成する場合には、感光層を傷つけやすく、塗布層が不均一に成ったり、電荷移動性に差違が生じ、画像品質に問題が生じる。
上記したように、この方法は潤滑剤の摩擦係数を低減するには有効な手段であるが、逆に問題を起こす要因にもなる。
【００１８】
したがって、本発明の課題は、従来法に比して感光体にスクラッチなどの外観不良を与え難い構造の潤滑性付与部材装置を提供することである。本発明の他の課題は、前記潤滑性付与部材装置との組み合わせによって摩擦係数を好適な範囲に設定し、トナークリーニング性を向上させ、高湿環境でも良好な作像性が得られる画像形成装置を提供することである。
【００１９】
【課題を解決するための手段】
本発明によれば、第一に、潤滑性付与部材、第１の弾性部材、第２の弾性部材の順に積層される構造を有する潤滑性付与部材装置であって、４．７５ｃｍ２のエリアに１００ｇの荷重を掛けたとき、第１の弾性部材が２０％以上の圧縮率を有し、かつ第２の弾性部材が１〜１０％の圧縮率を有し、しかも該第１の弾性部材が起毛部材であることを特徴とする潤滑性付与部材装置が提供される。
【００２０】
第二に、潤滑性付与部材、第１の弾性部材、第２の弾性部材の順に積層される構造を有する潤滑性付与部材装置であって、４．７５ｃｍ ２ のエリアに１００ｇの荷重を掛けたとき、第１の弾性部材が４０％以上の圧縮率を有し、かつ第２の弾性部材が１〜１０％の圧縮率を有することを特徴とする潤滑性付与部材装置が提供される。
【００２２】
第三に、第１の弾性部材が発泡材であることを特徴とする上記第二に記載の潤滑性付与部材装置が提供される。
【００２３】
第四に、潤滑性付与部材が膜厚１００〜４００μｍのフィルム状フッ素系樹脂であることを特徴とする上記第一〜三のいずれかに記載の潤滑性付与部材装置が提供される。
【００２４】
第五に、潤滑性付与部材の作用領域が、感光体の長手方向で最大画像形成領域の幅もしくはそれ以上の幅であることを特徴とする上記第一〜四のいずれかに記載の潤滑性付与部材装置が提供される。
【００２５】
第六に、上記第一〜五のいずれかに記載の潤滑性付与部材装置が、単独のユニットで、もしくは他のプロセス装置との組み合わせで、或いはプロセスカートリッジ内に組み込まれ、感光体又は塗布部材と接触配置され、かつ感光体と上質紙の間の静止摩擦係数（以下、単に摩擦係数と云う）が０．１〜０．４に設定されて画像形成を行うことを特徴とする画像形成装置が提供される。
【００２６】
第七に、潤滑剤塗布部材が接触帯電装置の帯電部材を兼ねることを特徴とする上記第六に記載の画像形成装置が提供される。
【００２７】
第八に、プロセスカートリッジが感光体、帯電装置及びクリーニング装置、もしくは感光体及び帯電装置から構成され、上記第一〜五のいずれかに記載の潤滑性付与部材装置を該感光体もしくは該帯電部材のいずれかと接触作用する様に配置して画像形成を行うことを特徴とする上記第六又は七に記載の画像形成装置が提供される。
【００２８】
【発明の実施の形態】
以下、本発明をさらに詳細に説明する。
本発明の潤滑性付与部材装置は潤滑性付与部材と弾性部材とで構成され、さらにその弾性部材は圧縮率の大きい第１の弾性部材と、第１の弾性部材より圧縮率の小さい第２の弾性部材との２種類の部材で構成されたものである。此の構成とすることにより、潤滑性付与部材が受ける異物を程良く吸収し、圧を分散するため、感光体に対しての影響を小さくし、感光体もしくは塗布部材にスクラッチを発生する場合でも、影響を軽微に抑制することができる。
【００２９】
ここで、圧縮率は次のように規定する。
２２〜２６℃／５５〜６５％ＲＨの環境下で、弾性部材を２ｃｍ角で、厚みを１０±２ｍｍとし、４．７５ｃｍ2の面積に１００ｇの荷重を掛ける前後の厚みの変化を測定し下式で算出する。
圧縮率＝（元の厚み−圧縮後の厚み）／元の厚み×１００（％）
【００３０】
本発明の潤滑性付与部材装置においては、上記と同じ条件で測定したときの圧縮率が、２０％以上の起毛部材（好適な起毛の高さは０．１〜１ｍｍ程度）からなる第１の弾性部材と、１〜５％である第２の弾性部材とを組み合わせたものである。これにより、感光体もしくは塗布部材にスクラッチを与えること無しに、もしくは与えたとしてもダメージを最小限に抑制し、結果として良好な画像品質を維持させることができる。
【００３１】
また、本発明の他の潤滑性付与部材装置においては、上記と同じ条件で測定したときの圧縮率が、４０％以上である第１の弾性部材と、１〜５％である第２の弾性部材とを組み合わせたものである。これにより、感光体もしくは塗布部材にスクラッチを与えること無しに、もしくは与えたとしても、ダメージを最小限に抑制し、結果として良好な画像品質を維持させることができる。
【００３２】
また、本発明の潤滑性付与部材装置においては、上記の圧縮率が４０％以上の第１の弾性部材に発泡材を用いることによって、感光体もしくは潤滑剤塗布部材への摺擦、異物の押圧を吸収、分散し、均等な当たりを実現し、感光体の傷付きを防止もしくは抑制し、結果として長期に亘って良好な画像品質を維持させることができる。
【００３３】
また、本発明の潤滑性付与部材装置においては、潤滑性付与部材としてフッ素系樹脂特に４フッ化エチレン樹脂（ＰＴＦＥ：ポリテトラフルオロエチレン樹脂）を使用することが好ましく、これにより１００〜４００μｍの厚みのフィルム状、感光体の摩擦係数を低減化させ、感光体の摩耗を大きく抑制することができる。
【００３４】
また、本発明の潤滑性付与部材装置においては、潤滑性付与部材の感光体もしくは塗布部材に作用する範囲は少なくとも画像形成領域、もしくはそれ以上の長さ（幅）にすることによって、全画像領域にわたって均一な作像性を維持することが可能となる。
【００３５】
また、本発明の画像形成装置においては、前記の潤滑性付与部材装置を画像形成装置内に単独に設置させるユニットか、もしくは他のプロセスユニット、例えば、クリーニング装置や帯電装置等との組み合わせにして、画像形成装置内にもしくはプロセスカートリッジに組み込み画像形成装置に装着させ、かつ感光体もしくは塗布部材を介して感光体の摩擦係数を０．１〜０．４の範囲で画像形成を行うことにより、感光層の摩耗を大幅に抑制できるとともに、良好な作像性を維持することができる。
【００３６】
また、本発明の画像形成装置においては、塗布部材に接触帯電装置の帯電部材（帯電ロール）を利用することによって、画像形成装置自体をコンパクトに設計でき、他方、感光体の傷付きを一段と抑制でき、また潤滑剤を均一に効率よく付与できるため、感光体の表面摩擦係数はより均一化が可能となる。
【００３７】
さらに、本発明の画像形成装置においては、少なくとも感光体、帯電装置及びクリーニング装置、もしくは感光体及び帯電装置でプロセスカートリッジを構成し、その中に潤滑性付与部材装置を組み込むことによって装置がコンパクト化でき、また、潤滑性付与部材を感光体と直接もしくは塗布部材を介して感光体に潤滑剤を付与しながら作像することにより、感光体の摩擦係数を効率よく均一に低減化させることが可能となる。
【００３８】
続いて、本発明に使用される複写プロセスについて説明する。
図１に複写プロセスの概念図を示す。感光体１０１は帯電装置１０２により(±)５００〜１０００Ｖ程度に帯電される。近年は環境に配慮してオゾンの発生の少ない接触帯電装置が使用される例が多い。帯電装置には接触帯電装置以外にコロナ帯電装置がある。図１の例では帯電ロールを用いた接触帯電装置である。
【００３９】
接触帯電装置の帯電ロールは芯金上に導電処理された弾性体（例えば、カーボンや、活性炭素繊維、金属粉などの導電性粉末をゴム材、アクリル系樹脂などに分散し、アスカーＣ硬度で５０度前後に加工したもの）、１０10〜１０13Ω・ｃｍ程度の抵抗を有するヒドリンゴムなどの部材を単層もしくは積層に成形加工したものが使用され、（±）１０００〜２０００Ｖ程度の直流電圧、もしくは交番電流（周波数５０Ｈｚ〜１０ｋＨｚ）を重畳した直流電圧が印加され、感光体１０１に電荷が付与される。
【００４０】
感光体１０１には有機系感光体（ＯＰＣ）が使用される。感光体１０１はマイナス帯電、プラス帯電によって構成が異なるが、大略は図２（ａ）〜図２（ｄ）に示す様な構成である。
感光体１０１はアルミニウム（Ａｌ）やステンレススティール（ＳＵＳ）の他、導電処理した樹脂、紙製品または硝子等からなる円筒状の導電性支持体１が用いられる。導電性支持体１にはその導電性支持体からの電荷注入を阻止し、光像の反射を抑制する働きを成す為に、２〜２０μｍの膜厚を有するＴｉＯ2等の金属酸化物の微粒子をバインダー中に分散した１０6〜１０10Ω・ｃｍ程度の中抵抗の下引き層２が形成されるのが好ましい。
下引き層２上に形成される感光層は使用プロセス（アナログ方式、デジタル方式、＋帯電、−帯電）によって異なり、図２（ａ）〜図２（ｄ）の様な構成となる。
【００４１】
図２（ａ）は下引き層２上に電荷輸送材と電荷発生材（アゾ顔料や金属フタロシアニン系など）を一体化した感光層５を形成した単層タイプであり、図（ｂ）は下引き層２を形成せずに、導電性支持体１上に直に厚さ０．１５〜０．２μｍの電荷発生層３を形成し、さらに１０15〜１０17Ω・ｃｍ程度の体積抵抗のポリカーボネート樹脂（Ａ型ポリカ、Ｃ型ポリカ、Ｚ型ポリカなど）やポリオレフィン樹脂などをバインダー樹脂としてドナーで正孔移動度を高められた厚さ１０〜５０μｍの電荷輸送層４を形成した機能分離型の感光体であり、図２（ｃ）は下引き層２上に順に電荷発生層３、電荷輸送層４を形成した機能分離型の感光体であり、図（ｄ)はさらに電荷輸送層４の上に保護層６を形成した感光体である。プラス帯電の場合は図２（ａ）の構成が多く使用され、マイナス帯電の場合は図２（ｂ）〜図２（ｄ）の構成の感光体が多く使用される。
【００４２】
感光体にプラスもしくはマイナス電荷の付与（荷電）が行われたのち、画像露光１０３が感光体１０１面に行われる。
アナログ複写機の場合、ハロゲンランプや蛍光灯などの露光ランプで照射された原稿像が可視光投影され、デジタル複写機の場合にはＣＣＤ（電荷結合素子）で読みとられた原稿像が６３０〜７８０ｎｍのＬＤやＬＥＤのデジタル信号に変換されて、感光体１０１上に結像される。
【００４３】
結像によって感光層では電荷分離が行われ、感光体に潜像形成が行われる。原稿に応じた潜像形成が行われた感光体は現像装置１０４で１成分もしくは２成分の現像剤により現像が行われ、原稿像は顕像化（トナー像）される。
【００４４】
感光体上のトナー像は転写装置１０５によりコピー用紙１０９に転写後、このコピー用紙は転写装置１０５から分離され、定着装置１０８に送られハードコピーとなる。一方、感光体１０１はトナー像の転写後、クリーニング装置１０６で残留トナーが清掃された後、潤滑性付与部材装置２００により潤滑剤が感光体１０１に付与され、感光体１０１の表面摩擦係数が好適なレベルまで低減化、維持された後、除電装置１０７で残留潜像を消去されて一連の複写プロセスは終了する。
【００４５】
次にこの複写プロセス上の問題点について述べる。
感光体への電荷の付与手段（帯電）として実用化されているものには、コロナ帯電法（ワイヤー、鋸歯状電極など）や接触帯電法（導電性ブラシ、帯電ロールなど）などがある。
帯電装置には直流電圧、もしくは高湿環境及び低湿環境でより帯電安定性が得られる交番電流（５０Ｈｚ〜１０ｋＨｚ）を重畳した直流電圧（交流重畳直流電圧）が印加され、感光体の表面電位は（±）５００〜１０００Ｖ程度に設定される。
【００４６】
感光体を帯電装置で帯電する際には多かれ少なかれ放電現象を伴うため、先に指摘したように、電荷以外の副産物としてオゾン（Ｏ3）や窒素酸化物（ＮＯｘ）などのコロナ生成物が発生する。
このコロナ生成物が感光体に作用すると電子写真特性を劣化させたり、感光層の表面抵抗を低下させ、解像性低下、さらには全面画像流れを引き起こしやすくなる。また、コロナ生成物が感光体に付着し、さらには感光層に浸透することによって、感光層の摩擦係数を高め、感光層の摩耗が促進され、感光体寿命が短くなるという問題がある。
【００４７】
接触帯電法は印加電圧がコロナ帯電法の１／３〜１／５程度と低い電圧で動作するため、コロナ帯電法に比べオゾンの発生量はコロナ放電法の１／１００〜１／２００程度（０．１ｐｐｍ以下）、窒素酸化物は１／５０〜１／１００程度（０．０１ｐｐｍ以下）と少なく環境面において有利である。しかし、感光体の極間近での現象であるため、発生したコロナ生成物はほぼ１００％感光体に作用する。
一方、コロナ放電法の場合には感光体と帯電装置が離れているため、印加電圧は接触帯電装置の３〜５倍程度に高くする必要があり、コロナ生成物の発生は極めて多い。しかし空間があるためコロナ生成物が散逸し、また排気装置を作用させ易いため、感光体が受けるダメージは接触帯電装置とコロナ帯電装置では同等かむしろコロナ放電法の方が少ない場合がある。
【００４８】
生成されたコロナ生成物の内、ＮＯｘは感光層表面に付着し大気中の水分により硝酸となり、表面抵抗を低下させるため、解像度の低下を起こし、ひどい場合には画像流れにいたる。更に粘性があるためトナーや紙粉などの異物を吸着し易く、帯電ロールを汚染し地汚れの原因ともなる。
一方、オゾンは化学的性質として漂白作用や強力な酸化作用があるため、感光体を変色（黄変、脱色など）させたり、感光体の構成物質の分子間結合を切断したり、感光体の輸送能力、感光性機能を低下させる。
【００４９】
ところで有機系感光体の製造時、感光層（電荷輸送層）には必要に応じて、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等のモノフェノール化合物、２，２’−メチレン−ビス−（４−エチル−６ｔ−ブチルフェノール）等のビスフェノール系化合物、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）ベンゼン等の高分子フェノール系化合物、ハイドロキノン類、有機燐化合物類等の酸化防止剤もしくは酸化抑制剤、あるいは可塑剤を重量比で１〜２０％添加される場合がある。しかし、高耐久感光体になるほど、オゾン等の感光層への影響を回避することは難しく、帯電装置の停止後でも感光層表層に作用し続ける為、大気中の水分を吸着し画像品質低下を招くことがある。
【００５０】
有機系感光体は摩耗しやすい為、感光体が回転している間は劣化した最表層が削り取られ新しい面が出ることから、画像の劣化を回避できるというメリットもあるが、最表層の削れが大きいとプロセススピードが速い画像形成装置では感光体を頻繁に交換する必要が生じる。
【００５１】
なお、摩擦係数を上昇させ、感光体特性、画像品質を低下させるなどの主となる要因物質としてコロナ生成物に付いて記述を行ったが、それ以外にも感光体表面に付着することで影響を与える要因物質としては、トナーの構成物質（帯電制御剤等）キャリアの構成物質（被覆剤など）、紙に含まれる結着剤など、感光層の削れ紛、定着装置から出るガス成分などがある。
【００５２】
次に、感光体の摩耗を抑制し、画像品質を安定化させる方法について述べる。感光層の摩耗は次のような作用によって起こる。すなわち、コロナ生成物によって感光層が化学的劣化を起こし、コロナ生成物やトナー構成物などの付着によりブレードの接触抵抗が上がり、トナー、磁性粉などの塊がブレードに挟まりスクラッチを起こし易くなるためである。
【００５３】
このため、感光層の摩耗を抑制する為には感光体表層の摩擦係数を下げることが最も有効な手段である。感光体の摩擦係数を下げる手段としては、感光体に直接潤滑性付与部材を作用させる直接方法と、塗布部材に潤滑性付与部材を作用させ、塗布部材から感光体に潤滑剤を付与する間接方法がある。
直接方法では感光体に直接潤滑性付与部材を当接し、間接方法では潤滑性付与部材を塗布部材に当接して感光体の摩擦係数を低減化させる方法であるが、いずれも潤滑性付与部材による摺擦行為が有るため、潤滑性付与部材の当たりが強かったり、硬い部材を使用した場合には、感光体もしくは塗布部材に傷を与えたり、摩耗する可能性が高く、画像品質に影響を与える。
【００５４】
従って、潤滑性付与部材は感光体もしくは塗布部材に接したとき、スクラッチを生じない程度のソフトな圧力でニップを形成し、しかも均等に当接する様にする必要がある。従って、潤滑性付与部材をソフトに均等に感光体もしくは塗布部材に必要なニップを形成するためには、好適な潤滑性付与部材と、その潤滑性付与部材が感光体もしくは塗布部材に当接したときにソフトに接触し、トナーなどの異物が混入したとき、その影響を吸収し、感光体もしくは塗布部材に対する食い込み力を分散するような構造であることが重要である。
【００５５】
潤滑性付与部材装置の作製例を図３及び図４に示し、説明する。
図３は感光体に直接作用させて摩擦係数を低減化させるのに有用な潤滑性付与部材装置の構成例である。画像形成装置内に単独（図５参照）に、もしくはクリーニング装置１０６（図６参照）或いは帯電装置の側面（クリーニング装置側）等に取り付けて使用することができる。
図４は塗布部材に作用させて、間接的に感光体の摩擦係数を下げるための潤滑性付与部材装置の構成を示す一例である。内容的には図３にほぼ同じ構成である。帯電ロールを塗布部材として使用する一例を図７に示す。
【００５６】
図３の潤滑性付与部材装置の構成について説明する。基体２０１には０．３〜２ｍｍ程度の厚みのステンレススティール（ＳＵＳ）や鉄板、アルミニウム（Ａｌ）板などが使用される。基体２０１上に第１の弾性部材２０３と第２の弾性部材２０２が重ね合わされ張りつけられる。図中、２０４は補助部材、２０５は潤滑性付与部材である。
第１の弾性部材２０３は第２の弾性部材２０２より圧縮率が高くなければならない。
【００５７】
第１の弾性部材２０３の一つには起毛高さが０．１〜１ｍｍ（起毛部材全体の厚みは１〜２ｍｍ程度）程度の起毛部材が使用される。起毛部材には別珍、フランネル、ベルベット、ポリエステル製もしくはポリウレタンとの混織りの人工皮革品などがあり、市販品のものが利用でき、できれば起毛部に復元性の高い部材が望ましい。
この起毛部材は前記圧縮率の測定法で２０％以上のものである。２０％未満の圧縮率であると、異物等に対する吸収、分散の効果が不足し、スクラッチを起こしやすくなる。
【００５８】
第１の弾性部材の他の１つには、前記圧縮率が４０％以上の弾性部材が使用される。特に、発泡材が異物に対する押圧の分散、吸収に効果的で、厚み２〜６ｍｍ程度、密度２０〜５０ｋｇ／ｍ３、引っ張り強度０．５〜１．５ｋｇ／ｃｍ２程度の特性を示すフォーム（スポンジ形態）がほぼ前記圧縮率に含まれる。
【００５９】
第２の弾性部材２０２には第１の弾性部材より硬めの部材が使用される。
圧縮率１％以上、１０％以下の弾性部材が使用される。圧縮率が１％未満では硬くなりすぎ、第１の弾性部材の効果を生かせない。また、１０％を超えると、柔らかすぎ、潤滑性付与部材が感光体に当接したとき、好適な当接圧を与えることができず、所定の摩擦係数に設定することができない。好適には圧縮率２％〜５％、密度５０〜６０ｋｇ／ｍ３、引っ張り強度１ｋｇ／ｃｍ２前後の特性を示すフォーム（スポンジ形態）の弾性部材がほぼ前記圧縮率に含まれる。
第２の弾性部材の厚みも２〜６ｍｍ程度で要求される仕様に合わせて選定する。
【００６０】
潤滑剤を感光体１０１に付与するための潤滑性付与部材２０５には多くの種類があるが、特にフィルム状フッ素系樹脂が好ましく、その中でも４フッ化エチレン樹脂（ＰＴＦＥ：ポリテトラフルオロエチレン）が好適である。
４フッ化エチレン樹脂（ＰＴＦＥ：ポリテトラフルオロエチレン）は各種フッ素系樹脂の中でも、軽い摺擦で相手の部材に転移しやすく、摺擦した相手（ここでは感光体もしくは塗布部材を指す）の摩擦係数を０．１以下まで低下させる優れた潤滑性を有し、粒子が極めて細かいため、感光体に転移すると極めて薄い膜を形成し、光学特性からの画像品質劣化はなく、固体であるため、取扱いも容易である。
【００６１】
フィルム状潤滑性付与部材２０５の膜厚は１００〜４００μｍが好適である。膜厚が１００μｍよりも薄いと、柔軟性が高くスクラッチを与えにくくなるが、耐久性が不十分となり交換を頻繁に行う必要が生じる。また、４００μｍより厚くなると、厚くなるほど柔軟性に欠けて来るので、第１の弾性部材の効果をもってしても吸収しきれず、感光体を傷つける可能性が高くなる。通常は２００〜３００μｍが適当である。
この潤滑性付与部材にはニチアス社、ダイキン工業社、日東工業社、３Ｍ社などの製品が入手可能である。
【００６２】
補助部材２０４は第１の弾性部材の弾力性を維持することと変形をできるだけ維持するための部材として使用されるため、潤滑性付与部材及び第１、第２の弾性部材の機能を維持する範囲の使い方にする必要がある。補助部材２０４の材質は厚さ０．１〜０．５ｍｍ程度のポリエチレンテレフタレート（ＰＥＴ）、ポリカーボネート樹脂板、燐青銅板などが使用され、潤滑性付与部材２０５は補助部材２０４に接着される。感光体と接触する部位近傍では接着層は使用すべきではない。ただし、使用材質や、接着法によっては補助部材は必ずしも必要とはしない。
【００６３】
続いて、図４の潤滑性付与部材装置の構成について説明する。図４は塗布部材を介して感光体の摩擦係数を低減化させるための別の潤滑性付与部材装置２００の一例である。塗布部材には帯電ロールを利用するのがコンパクトになり、摩擦係数もコントロールしやすい。帯電ロールの材質は耐久性の面から前記したようなゴム系やアクリル系の材質のものが使用されるが、帯電部材は感光体より耐摩耗性がある為、少し高めの当接圧に設定することができる。
間接方法では一旦塗布部材に潤滑剤を付与した後、感光体に付与させる形を取るため、十分な潤滑剤の供給が必要である。潤滑剤の感光体への転移量は感光体及び塗布部材の径や複写スピード（線速）、帯電ロールに付設されたクリーニング部材（図６、図７参照）のクリーニング間隔、原稿の画像密度などによって左右される。
【００６４】
潤滑性付与部材を適正条件で画像形成装置に搭載することによって、感光体の摩擦係数を適正な範囲（０．１〜０．４）に設定する。此の結果、感光体表層に付着したコロナ生成物や残留トナーはクリーニングが容易になり、感光層の最表面に極薄く付着した残留コロナ生成物や、トナー構成物など画像品質に対しての有害物質は摩擦係数のレベルに従い軽く削られるため、画像品質が程良く維持され、しかもブレードや、現像剤の感光体に対する抵抗力も軽減されているため摩耗も抑制される。
【００６５】
図８に摩擦係数（千枚〜５万枚平均値）と５万枚複写時の感光層の摩耗量との関係を示す。
感光体の摩擦係数の好ましい範囲は０．１〜０．４である。此の数値は画像品質にほぼ依存し、摩擦係数が０．１程度になると、感光体表層に付着した前記のコロナ生成物などの汚染物質が滑りのため除去されず、９０％ＲＨ程度の高湿環境では画像流れを起こしやすくなり、また、０．４より大きくなると、感光層の摩耗が促進され、感光特性の劣化で感光体寿命が短くなる。
【００６６】
感光体の摩擦係数は画像の安定性、感光層の摩耗量から、０．２〜０．３の範囲に成るように設定するのがより望ましい。但し、オゾンなどのコロナ生成物の生成が皆無に近い帯電装置（例えば、誘起帯電装置、活性炭素繊維部材を使用した接触もしくは非接触帯電装置など）を使用すれば０．１５程度もしくはそれ以下の摩擦係数であっても十分実用性を持たせることも可能であり、更なる高耐久化が達成できる。
【００６７】
摩擦係数は当接圧及びニップで左右される。通常、ニップは２ｍｍ前後形成されれば良く、当接圧は後述する測定法で１０〜２０ｇ程度で有れば、２０〜４０ｃｐｍの画像形成装置の中速機に対処でき、それ以上の複写枚数の画像形成装置には、ニップをもう少し稼ぐような構造にすることで対処可能となる。
【００６８】
潤滑性付与部材の作用領域は少なくとも画像形成領域、もしくはそれを越える幅で設定することが望ましい。すなわち、画像形成領域内で設定した場合、感光体の削れに段差が生じるため、削れが進んだ潤滑性付与部材外の部位では、複写が進につれ地汚れが起こり易くなる危険性を有すためで、好ましくは、コピー用紙のズレ等を考慮し、画像形成領域よりも超える領域で潤滑性付与部材の幅が設定される。
【００６９】
次に潤滑性付与部材装置の取り付け位置について説明する
図３に示すような形態の潤滑性付与部材装置２００は画像形成に障害を与えない位置であれば感光体上のどの位置でもかまわないが、好ましくはクリーニング装置１０６と除電ランプ１０７もしくは帯電装置１０２との間に設置する（図５、図６参照）。この位置であれば、画像形成装置が作動中であっても、作像に関係なく常時作動することが可能なためである。設置方法は単独でも良く、他のプロセス装置（クリーニング装置、帯電装置など）と組み合わせて設置しても良い。
【００７０】
クリーニング装置はブレードクリーニング単体使用のもの、もしくはクリーニングブラシを併用した装置のいずれにも使用できる。フッ素樹脂は削れ微粉末になるが、その微粉末が塊として感光体に固着することがある。そのため黒ベタ画像では白斑点になり、画像品質に影響を及ぼす。この現象を回避する手段としては、掻き取り効果の高いクリーニング性良好なブラシ材（例えば、ループブラシ（ＳＡ−７、アクリル系））などを使用することにより、摩擦係数を適当な値に維持しながら、摩耗とのバランスを図ることができる。
【００７１】
図４に示すような形態の潤滑性付与部材装置は塗布部材としての接触帯電装置の帯電ロールに当接するような形で設置する。設置する位置はどの位置でも良い。好ましくは帯電ロールのクリーニング部材の下手（出口側）で、帯電ロールの回転を損なわない程度の当接圧に設定する。帯電ロールのクリーニング部材は５０枚もしくは１００枚毎に間欠的に作動する方式が望ましい。これは、一旦帯電ロールに付与された潤滑剤が、クリーニング部材で削除されてしまう為に、感光体に移行する量が少なくなり、所定の摩擦係数が得られ難いためである。
【００７２】
潤滑性付与部材装置は単独でも、他のプロセス装置と組み合わせて、画像形成装置内に交換部品として設置するか、少なくとも、感光体と帯電装置、もしくは感光体、帯電装置及びクリーニング装置からなるプロセスカートリッジに組み込むことができる。
【００７３】
なお、本文中で記述する摩擦係数は下記測定方式で算出したものとする。
測定用の感光体を固定し、ベルトとして厚さ８５μｍ、幅３０ｍｍ、長さ２９０ｍｍにカットした上質紙を用意し、前記上質紙を感光体の上に乗せ、ベルト端部の一方に１００ｇの分銅を取り付け、もう一方の片端に重量を測るデジタル・フォース・ゲージを取り付け、デジタル・フォース・ゲージをゆっくり引き、ベルトが移動開始する時の重量を読みとり、次の式で静止摩擦係数を計算する。
μｓ＝２／π×ｌｎ（Ｆ／Ｗ）
ただし、μｓ：静止摩擦係数、Ｆ：読みとり荷重
Ｗ：分銅の重さ π：円周率
この測定法（オイラー・ベルト方式）についての関連記ことは特開平９−１６６９１９号にも記載されている。
【００７４】
また、本文中で記述した当接圧は次のように規定したものである。
長さ１００ｍｍ、幅３０ｍｍ、厚さ８５μｍの上質紙（ベルト）を感光体もしくは塗布部材と潤滑性付与部材間に挿入し、前記のデジタル・フォース・ゲージで引っ張り出されるときの最大値を読みとり、その値を当接圧と規定する。単位はｇで表す。
【００７５】
【実施例】
以下、実施例及び比較例をあげて本発明を具体的に説明する。
【００７６】
（評価方法）
効果確認用の装置として、ＭＦ２００機、ＭＦ３５００機（ブラシ材としてＳＡ−７（アクリル系、東レ社製）を用いたブラシクリーニング方式に改造：いずれもリコー社製電子写真複写機）を用意し、以下に示す方法及び条件で評価を行った。ブラシの回転数は３３０ｒｐｍ、カウンター方向に回転する。
評価方法はＡ４サイズ横送り連続通紙を行い、１０００〜５０００枚毎に指定の原稿による画像評価、前記の方法による摩擦係数を測定し、１万枚毎にフィッシャー社の渦電流式の膜厚計（型式ＭＭＳ）を使用し膜厚測定を上記測定項目に加えて、効果確認を行った。
評価環境は２２〜２４℃／６０〜７０％ＲＨ、および３０℃／９０％ＲＨである。
【００７７】
（感光体の作製法）
評価に使用する感光体は以下の手順によって作製した。
厚さ１．２ｍｍ、φ３０ｍｍ（ＭＦ２００機用）もしくはφ６０ｍｍ（ＭＦ３５００機用）、長さ３４０ｍｍのアルミニウムドラムに下記処方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順次塗布し、各層形成毎に乾燥することにより、厚さ３．５〜４μｍの下引き層、厚さ０．２〜０．２５μｍの電荷発生層、厚さ２４〜２８μｍの電荷輸送層をそれぞれ形成し、電子写真感光体を作製した。なお、下記の部はいずれも重量部表示である。
【００７８】
〔下引き層用塗工液〕

Figure 0003865555
【００７９】
〔電荷発生層用塗工液〕
オキソチタニウムフタロシアニン顔料 ５部
ポリビニルブチラール（ＵＣＣ：ＸＹＨＬ） ２部
テトラヒドラフラン（ＴＨＦ） ８０部
【００８０】
Figure 0003865555
【化１】
Figure 0003865555
塩化メチレン １００部
メチルフェニルシリコーンオイル（５０ｃｓ） 数滴
【００８１】
（実施例１）
５ｍｍ×３１０ｍｍ×８ｍｍの寸法で、圧縮率２％の軟質スポンジＥＰを第２の弾性部材として、また３１０ｍｍ×８ｍｍの寸法で、圧縮率４０％、起毛高さ１ｍｍのベルベットを第１の弾性部材として、これらを両面テープで張り合わせ、２枚合わせの弾性部材を作製した。
これを０．３ｍｍ×３１０ｍｍ×１７ｍｍの寸法のＳＵＳ板に接着剤を用いて接着した。
ついで、補助部材として０．２ｍｍ×３１０ｍｍ×１１ｍｍの寸法にカットしたＰＥＴフィルムを基体の下端より４ｍｍ出るように、ベルベットの前面および基体に両面テープで張り、最後に両面テープを用いて０．２ｍｍ×３１０ｍｍ×８ｍｍのＰＴＦＥフィルム（ニチアス社製、＃９００１）を４ｍｍ幅の補助部材に張り、図３に示すような潤滑性付与部材装置を作製した。この様にして作製した潤滑性付与部材装置をＭＦ３５００機のクリーニング装置部にスペーサーを使用して取り付け、感光体との当接圧を１５〜１８ｇの条件にセットし評価を行った。
【００８２】
（実施例２）
第１の弾性部材として８ｍｍ×３１０ｍｍの寸法で、圧縮率３３％、起毛高さ約０．３ｍｍの不織布（ポリエステル製）、補助部材として０．３ｍｍ×３１０ｍｍ×１１ｍｍの寸法にカットしたＰＴＦＥフィルム（ニチアス社製、＃９００１）を使用した以外は実施例１と同様にして潤滑性付与部材装置を作製した。これをＭＦ３５００機に搭載し、実施例１同様の評価を実施した。
【００８３】
（実施例３）
第１の弾性部材として８ｍｍ×３１０ｍｍの寸法で、圧縮率２１％のエクセーヌ（ポリエステル繊維とポリウレタン繊維との混紡、東レ社製）、補助部材として０．３ｍｍ×３１０ｍｍ×１１ｍｍの寸法にカットしたＰＴＦＥフィルムを使用した以外は実施例１と同様にして潤滑性付与部材装置を作成した。これを実施例１と同様の条件で同様の評価を実施した。
【００８４】
これらの評価結果を表１に示す。
実施例１、２に示す圧縮率１５％、２０％の弾性部材を使用した潤滑性付与部材装置では、ともにスクラッチの影響、ハーフトーン画像は殆ど問題なく、感光層の摩耗も少なかった。実施例３ではスクラッチが２本程度黒ベタ画像に微かに現れ、ムラも少し生じた。しかし、文字画像の背景部に異常は無かった。
【００８５】
【表１】
Figure 0003865555
【００８６】
（実施例４）
実施例１と同様の５ｍｍ×３１０ｍｍ×８ｍｍの寸法で、圧縮率２％の軟質スポンジＥＰからなる第２の弾性部材、２ｍｍ×３１０ｍｍ×７ｍｍの寸法で圧縮率６５％のウレタンフォームＲＳ（イノアック社製）からなる第１の弾性部材、同じく実施例１に記載したのと同様の補助部材、ＰＴＦＥフィルム（ただし厚さ３００μｍ）および実施例１に同寸法の基体を用いて、潤滑性付与部材装置を作製した。これをＭＦ３５００機のクリーニングブレードの部位にスペーサーを使用して、感光体との当接圧が１５〜１８ｇに成る様に固定した。これを実施例１同様の評価を実施した。
【００８７】
（実施例５）
第１の弾性部材を圧縮率６０％のＥＭＯ（イノアック社製）に変えた以外は実施例４と同様にして潤滑性付与部材装置を作製し、同様の評価を実施した。
【００８８】
（実施例６・・・参考例）
第１の弾性部材を圧縮率２７％のＥＣＡ（イノアック社製）に変え、潤滑性付与部材（ＰＴＦＥ）の厚さを２００μｍに変えた以外は実施例４と同様にして潤滑性付与部材装置を作製し、同様の評価を実施した。
【００８９】
これらの結果を表２に示す。圧縮率６５％、圧縮率６０％の第１の弾性部材を使用した実施例４及び５はいずれもスクラッチの影響はなく、感光層の摩耗も少なく、良好であった。実施例６（参考例）の、圧縮率２７％の第１の弾性部材を使用した潤滑性付与部材装置ではスクラッチが黒ベタ画像に白筋が微かに数本、ハーフトン画像では高湿環境でムラが少し現れたが、地肌部には黒筋は発生せず概ね良好であった。
【００９０】
【表２】
Figure 0003865555
注）実施例６は参考例である。
【００９１】
（実施例７）
圧縮率が２％で、２ｍｍ×３１０ｍｍ×５ｍｍのウレタンフォームＬＥ−２０（イノアック社製）からなる第２の弾性部材、圧縮率が３３％で、３１０ｍｍ×５ｍｍの寸法の不織布からなる第１の弾性部材を、０．１ｍｍの厚みのＰＥＴから成る補助部材、厚さ３００μｍの潤滑性付与部材、および、くの字型に加工した厚さ０．５ｍｍのアルミニウム基体を使用して図３に類似の潤滑性付与部材装置を作製した。これをＭＦ２００機のブレードクリーニング装置の金属板に帯電ロールに当接するように取り付け、帯電ロールとの当接圧を４０〜４５ｇに設定した。これを実施例１の同様の評価を実施した。
【００９２】
（実施例８）
第１の弾性部材を圧縮率４５％の別珍に変えた以外は実施例７と同様にして潤滑性付与部材装置を作製し、これを実施例７と同様にＭＦ２００機に取り付け同様の評価を実施した。
【００９３】
（実施例９）
基体として１．２ｍｍ×３１０ｍｍ×１５ｍｍのアルミニウム板を用意して、実施例８と同様の部材を使用し、図４に類似の潤滑性付与部材装置を作製し、帯電ロールユニットの金属部に潤滑性付与部材を両面テープで固定し、当接圧を４５〜５５ｇの間に設定し評価を実施した。なお、これを実施する際、帯電ロール付設のクリーニング部材を外した感光体ユニットを使用した。
【００９４】
これらの結果を表３に示す。
スクラッチに関しては実施例７〜９とも発生が無かった。画像ムラに関しては実施例７及び８とも問題は小さかったが、実施例９に関してはムラが少し生じた。また、摩擦係数が高い分、実施例７、８より感光層の摩耗が少し多目であった。解像性に関しては高湿環境に於いても全く問題は生じなかった。
【００９５】
【表３】
Figure 0003865555
【００９６】
（比較例１）
潤滑性付与部材装置を搭載しないでＭＦ３５００機で評価を行った。
【００９７】
（比較例２）
第１の弾性部材を使用しないで、第２の弾性部材に５ｍｍ×３１０ｍｍ×８ｍｍの寸法で圧縮率２％の軟質スポンジＥＰ、潤滑性付与部材に厚さ３００μｍのＰＴＦＥ、基体に０．３ｍｍ×３１０ｍｍ×１７ｍｍのＳＵＳ板を使用し、図３に示す潤滑性付与部材装置を作製した。これをＭＦ３５００機のブレードクリーニング部にスペーサーを使用し、感光体との当接圧が１４〜１８ｇ程度になるようにネジ止めを行い、実施例１と同様の評価を実施した。
【００９８】
（比較例３）
比較例２で示した厚さ３００μｍのＰＴＦＥの代わりに、厚さ５００μｍのＰＴＦＥを使用し、同様な潤滑性付与部材装置を作製し、同様の評価を実施した。
【００９９】
（比較例４）
第２の弾性部材として５ｍｍ×３１０ｍｍ×１０ｍｍで圧縮率２％の軟質スポンジＥＰ、潤滑付与部材として厚さ３００μｍのＰＴＦＥ、基体として１．２ｍｍ×３１０ｍｍ×１５ｍｍのアルミニウム板を用意し、潤滑性付与部材装置を作製した。これをＭＦ３５００機の帯電ロールの金属部に当接圧が４５ｇ前後の値を示すように取り付けた。これを用いて実施例１と同様の評価をした。
【０１００】
これらの結果を表４に示す。
比較例１では画像品質上の問題なかったが、摩擦係数は０．５以上の値を示し、感光層の摩耗が５万枚で平均５．６μｍと大幅な削れとなった。
比較例２では５万枚でのスクラッチ発生は少なかったが、その内深めのスクラッチがあり、地肌部に数本の黒筋及び帯状模様が発生した。
比較例３ではＰＴＦＥを５００μｍにしたため、感光体に対する当たりが局部的に高い部分が生じ、その部位ではスクラッチが集中的に起こり、黒筋の発生が見られた。
比較例４では帯電ロールに潤滑性付与部材を当接させたが、ニップの確保が不十分で摩擦係数が高めになった。しかも潤滑剤の付与が不十分であり、筋状模様が発生した。
【０１０１】
【表４】
Figure 0003865555
【０１０２】
（比較例５）
第１の弾性部材無しで、圧縮率が２％で、５ｍｍ×２５０ｍｍ×８ｍｍの寸法の軟質スポンジＥＰからなる第２の弾性部材、０．１ｍｍ×２５０ｍｍ×１１ｍｍの寸法のＰＥＴフィルムからなる補助部材、０．３ｍｍ×３１０ｍｍ×２０ｍｍの寸法のＳＵＳからなる基体、及び３００μｍ×２５０ｍｍ×９ｍｍの寸法のＰＴＦＥ（ニチアス社製、＃９００１）からなる潤滑性付与部材を夫々使用し、図３に類似の潤滑性付与部材装置を作製した。これをＭＦ３５００機のクリーニングブレードユニットに合わせて、スペーサーを利用し取り付け７．５万枚通紙で評価を行った。感光体に対する当接圧は１４〜１８ｇに設定した。これを用いて実施例１と同様の評価を行なった。
【０１０３】
（比較用実施例）
圧縮率４０％で、２５０ｍｍ×８ｍｍの寸法、起毛高さ１ｍｍのベルベットから成る第１の弾性部材、圧縮率２％で、５ｍｍ×２５０ｍｍ×８ｍｍの寸法の軟質スポンジＥＰからなる第２の弾性部材、０．１ｍｍ×２５０ｍｍ×１１ｍｍのＰＥＴからなる補助部材及びＰＴＦＥ（ただし厚さ３００μｍ）からなる潤滑性付与部材を夫々使用し、図３と同等の潤滑性付与部材装置を作製した。これを比較例５と同様に評価を実施した。
【０１０４】
結果を表５に示す。比較例５、比較用実施例ではコピー紙の幅が２９７ｍｍ（有効画像形成領域は２９３ｍｍ）であり、潤滑性付与部材の幅が２５０ｍｍと狭いため、潤滑性付与部材の作用しない領域外の感光層の摩耗が進行し、５．５〜６．２μｍの段差を生じ、クリーニング不良、帯電性に不備を生じ、両端部に薄く地汚れ状態が起こった。比較例５に関しては更に当接不均一による筋状模様がハーフトーン画像に僅かに生じた。
【０１０５】
【表５】
Figure 0003865555
【０１０６】
【発明の効果】
請求項１〜３に記載する本発明の潤滑性付与部材装置は、感光体もしくは塗布部材に当接し、感光体の摩擦係数を低減化させる部材として、基体、第１の弾性部材、第２の弾性部材及び、潤滑性付与部材で構成され、第１の弾性部材としてその圧縮率が２０％以上の起毛部材、或いは圧縮率が４０％以上の弾性部材を、第２の弾性部材としてその圧縮率が１〜１０％の部材を使用した潤滑性付与部材装置とすることで、感光体及び、塗布部材に摺擦時のダメージを与えることがない為、均一な画像品質を維持することが可能となった。
【０１０７】
本発明の潤滑性付与部材装置は、特に潤滑性付与部材に接する第１の弾性部材として圧縮率２０％以上の起毛部材とし、第２の弾性部材に圧縮率１０％以下、１％以上の弾性部材とを使用することによって、感光体もしくは塗布部材に対する当たりが均等でソフトに成り、異物の存在下でも局部的な圧を吸収するため、感光体もしくは塗布部材にスクラッチができることを極力避けることができるため、画像品質の劣化防止はもとより、感光体及び塗布部材の長期安定性を維持することができた。
【０１０８】
本発明の潤滑性付与部材装置は、特に第１の弾性部材として、圧縮率４０％以上の弾性部材（好適には発泡材）を使用し、第２の弾性部材に圧縮率１０％以下、１％以上の弾性部材とを使用することによって、当接がソフトになり、異物の影響が分散するため、感光体及び塗布部材がスクラッチなどのダメージを受けにくく、また、受けるダメージが狭い範囲に留めることができるため、良好な画像品質の維持が可能となり、また、感光体もしくは塗布部材の寿命を長くすることが可能となった。
【０１０９】
請求項４に記載する本発明の潤滑性付与部材装置は、潤滑性付与部材に４フッ化エチレン樹脂を選定することで、軽い圧力でも感光体の摩擦係数を下げることができ、また、１００〜４００μｍの膜厚とすることで、感光体もしくは塗布部材の受けるダメージを極力抑えることが可能となり、感光体もしくは塗布部材の耐久性は勿論のこと、画像品質も安定維持することが可能となる。
【０１１０】
請求項５に記載する本発明の潤滑性付与部材装置は、潤滑性付与部材の作用する範囲を感光体の長手方向の最大画像形成領域と同等の幅もしくはそれより少し長めとすることで、感光層の摩耗時に段差を生じることが無くなるため、地汚れを生じたり、濃度ムラを生じたりすること無しに、コピー画像全面に亘って均一な作像性を維持することができた。
【０１１１】
請求項６に記載する本発明の画像形成装置は、本発明の潤滑性付与部材が極めてコンパクトであるため、狭い領域にも設置が可能である。また、設置方法は装置単独でも、他のプロセス装置と組み合わせでも設置可能であり、画像形成装置内に、もしくはプロセスカートリッジに設置し、画像形成装置に収納することも可能となった。
【０１１２】
請求項７に記載する本発明の画像形成装置は、塗布部材を接触帯電装置の帯電部材（帯電ロール）を利用することで、コンパクトに設計が可能となり、所定の摩擦係数にコントロールが可能である。また、帯電ロールの摩擦係数が下がることによって、トナー、コロナ生成物などの汚染物質が付着しにくくなり、また、クリーニング性も高まることから、画像品質はＳ／Ｎ良好な画像が維持することができた。
【０１１３】
請求項８に記載する本発明の画像形成装置は、画像形成装置に搭載し、潤滑性付与部材装置を設置するプロセスカートリッジとしては少なくとも、感光体、帯電装置及びクリーニング装置、もしくは感光体と帯電装置から成るのが取扱いの面で有効である。このことにより、潤滑性付与部材の当接が安定しており、潤滑剤が安定して感光体に供給できるため、潤滑性付与部材装置は勿論、感光体、塗布部材の耐久性が維持され、結果的に画像品質を安定維持させることが可能となった。
【図面の簡単な説明】
【図１】潤滑性付与部材装置を組み込んだ本考案の複写プロセスの概略図である。
【図２】本発明に使用される感光体の層構成を示す概略図である。
【図３】潤滑性付与部材装置を説明する概略図である。
【図４】別の潤滑性付与部材装置を説明する概略図である。
【図５】コロナ帯電方式の画像形成装置に図３に図示した潤滑性付与部材装置を単独での取り付けを説明する概略図である。
【図６】図３に図示した潤滑性付与部材装置をブレードクリーニング装置に取り付けた例を示す説明図である。
【図７】図４に図示した潤滑性付与部材装置を塗布部材（帯電ロール）に取り付けた例を示す説明図である。
【図８】感光層表層の摩擦係数（１０００枚〜５００００枚時の平均値）と感光層摩耗量（５万枚後の摩耗量）の関係を示すグラフである。
【符号の説明】
１ 導電性支持体
２ 下引き層
３ 電荷発生層
４ 電荷輸送層
５ 感光層
６ 保護層
１０１ 感光体
１０２ 帯電装置
１０３ 画像露光系
１０４ 現像装置
１０５ 転写装置
１０６ クリーニング装置
１０７ 除電装置
１０８ 定着装置
１０９ コピー用紙
２００ 潤滑性付与部材装置
２０１ 基体
２０２ 第２の弾性部材
２０３ 第１の弾性部材
２０４ 補助部材
２０５ 潤滑性付与部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lubricant imparting member device for achieving a long life of a photosensitive member of an image forming apparatus such as a facsimile, a printer, and an electrophotographic copying machine, and achieving long-term stability of image quality, and image formation using the same. Relates to the device.
[0002]
[Prior art]
In image forming apparatuses such as facsimiles, printers, and electrophotographic copying machines using electrophotography, image formation is performed by sequentially applying the steps of charging, image exposure, development, transfer, cleaning, and static elimination to the photoreceptor. . Cadmium sulfide, cadmium selenide, amorphous selenium, amorphous silicon, and the like have been used for the photoreceptor, but in recent years, organic photoreceptors that have many merits such as easy production, high sensitivity, low cost, and no pollution. Is used in the mainstream.
[0003]
As a constituent material of the organic photoreceptor, a polycarbonate resin material (A type polycarbonate, C type polycarbonate, Z type polycarbonate, etc.) having high resistance, high transparency, and no polarity dependence is generally used. However, when this material is used as a binder to form a photosensitive layer, the Knoop hardness is 10 to 20 kg / mm.2Because of its low tension and low tensile strength, it is easily damaged and worn. Furthermore, in addition to the corona product generated from the charging device used during charging, toner components, paper powder, and the like adhere to the photosensitive layer surface, so that the resolution, cleaning performance, transfer efficiency, etc. Uniformity of the image is easily lost.
[0004]
In addition, the combination of the photoconductor and the cleaning blade (polyurethane rubber is mainly used) has a very high coefficient of friction, which causes problems such as high-frequency noise (blade squeal), electrical characteristics, and optical characteristics. However, there was a limit to improving the mechanical characteristics while maintaining various characteristics.
For this reason, a method for effectively utilizing the function of the lubricant was studied. The following are some examples of disclosures regarding improved methods using lubricants.
[0005]
(1) JP-A-56-51767:
As a means of eliminating contaminants adhering to the surface of the photoconductor and maintaining good image formation, a lubricating polishing member for an image holding member in which an abrasive and a lubricant are alternately formed is installed. Polishing and lubricant application are performed alternately to eliminate toner adhering to the photoreceptor and maintain high image quality.
[0006]
(2) Japanese Patent Laid-Open No. 56-113183:
A rotatable cylindrical lubricant replenishing member having a lubricant on the outer surface is brought into contact with the photosensitive member, and the lubricant is supplied to the surface of the photosensitive member, thereby stabilizing the image quality.
[0007]
(3) JP-A-6-342236:
A solid hydrophobic lubricant (a solid such as zinc stearate) is smoothly and stably supplied to an image carrier (photoconductor) via a charging roller to prevent occurrence of poor cleaning and filming.
[0008]
(4) JP-A-8-202226:
While controlling the coating amount of a lubricant (such as zinc stearate), an appropriate amount is always supplied to the image carrier via a brush to stabilize the image formation.
[0009]
(5) JP-A-8-305233:
In an image forming apparatus having means for detecting a toner image, the amount of lubricant supplied to the photoconductor is adjusted while controlling the number of rotations of the toner cleaning brush based on the detected contents, thereby stabilizing a high-quality image. Plan.
[0010]
(6) JP-A-11-2994:
When a digital copying machine is used in combination with a photoconductor having a layer having a fluorine resin powder dispersed on the outermost surface, the resolution is degraded due to scattering caused by spots during laser light irradiation. In order to avoid this phenomenon, instead of the layer in which the fluororesin powder formed on the photosensitive layer is dispersed, 10 to 10 in a binder resin or a material containing a fluororesin exhibiting releasability with respect to the toner. 90 wt% dispersed material is applied to the photoreceptor surface layer.
[0011]
In these disclosed examples, lubricant is supplied (externally added) to the surface of the photoconductor to prevent image quality deterioration, photoconductor damage, wear resistance, transfer efficiency (image loss prevention), improved cleaning properties, It suppresses image flow, prevents turning of the blade, extends the life of the cleaning blade, and the like.
[0012]
[Problems to be solved by the invention]
Next, the contents and problems of the above disclosed disclosure examples 1 to 6 will be described below.
Disclosure Example 1 (Japanese Patent Application Laid-Open No. 56-51767) is intended to maintain good image formation. After an abrasive layer such as cerium oxide and a lubricant layer composed of a fluorine-based resin such as ethylene tetrafluoride are alternately formed on a winding belt, and the deposit formed on the photosensitive layer is scraped with an abrasive. In this method, the surface of the photosensitive layer is kept clean while the surface property is restored with a lubricant.
The method in which the tetrafluoroethylene resin layer is applied to the photoconductor while being rubbed is highly efficient in reducing the coefficient of friction, but it is easy to scratch even if it is not an organic photoconductor with low hardness by simply contacting it. And streaks appear in the image. Further, since an abrasive is further used, the surface of the photosensitive layer is likely to be rough, and non-uniform shaving (for example, scratches, etc.) occurs and the image quality is liable to deteriorate. Furthermore, since the photosensitive layer is scraped more than necessary, there is a problem that the life of the photoreceptor is shortened.
[0013]
In disclosed example 2 (Japanese Patent Application Laid-Open No. 56-113183), a powdery lubricant is contained in a cloth pouch having pores, and the powdery lubricant is held on the outer surface thereof. The object is to apply a lubricant and reduce the frictional resistance between the blade and the photoreceptor.
When powdered lubricant is replenished from a rotating body, scattering is unavoidable and the surroundings are easily soiled. Further, it is difficult to control the coating uniformly with a thin layer, and the coefficient of friction tends to vary. If the amount of application is too large, image deterioration will also occur.
[0014]
In disclosed example 3 (Japanese Patent Laid-Open No. 6-342236), a lubricant is once applied to a charging roll (contact charging member) whose linear speed is different from the rotational speed of the photosensitive member, and then applied again to the photosensitive member. It has a lubricating effect. This method eliminates coating unevenness by changing the linear velocity and performs uniform coating. However, since a solid wax such as zinc stearate is used, coating unevenness is likely to occur. There is a high risk of non-uniform chargeability when applied to the surface. Due to this non-uniform charging, the uniformity of the halftone image is impaired, and image defects such as black spots, blurring, and background stains are likely to occur. Further, when zinc stearate is excessively applied, it is not easy to remove, and corona products from the charging device are involved, and resolution is likely to deteriorate.
[0015]
Disclosure Example 4 (Japanese Patent Laid-Open No. Hei 8-202226) is a method of reducing the friction coefficient of the photosensitive member by re-applying the lubricant once applied to the brush to the photosensitive member. Compared with the method of applying to the photoreceptor via a charging roll, this method uses a brush and selects the appropriate brush according to the material and the hardness of the ear, so that the lubricity is uniformly applied. Is possible.
When a zinc stearate having excellent lubricity is applied, the wear resistance is also excellent. However, it is difficult to control the uniform application of zinc stearate to an ultrathin layer, and since it becomes thick and difficult to remove when it adheres to the photoreceptor, the corona product (during the charging process) is durable. Low resistance substances such as image flow) and dust are likely to be caught, and the friction coefficient tends to gradually increase. When a single layer of zinc stearate is formed, the scraping effect is lowered, so that the friction coefficient is lowered too much, and there is a great risk of causing local image quality degradation. Therefore, when controlling the application of the lubricant, an accurate application control function is required to increase the S / N ratio of the sensor and to form an extremely thin layer.
[0016]
In disclosed example 5 (Japanese Patent Laid-Open No. 8-305233), in an image forming apparatus having means for detecting a toner image, a lubricant is applied to a photosensitive member while controlling the number of rotations of a toner cleaning brush based on the detected contents. The supply amount is adjusted to stabilize a high quality image.
Since this method automatically controls the coating amount based on the judgment from the image, it can be judged to some extent if there is a large degradation of the image, but it can hardly cope with the local degradation or slight degradation. In addition, when zinc stearate is continuously applied, contaminants such as corona products are taken in, the coefficient of friction gradually increases, and image flow is likely to occur due to the influence of the corona products.
[0017]
In disclosed example 6 (Japanese Patent Laid-Open No. 11-2994), when a fluororesin dispersion layer is formed on a photoreceptor layer, scattering occurs when irradiated with laser light, resulting in a decrease in resolution and a decrease in transfer efficiency. Due to the phenomenon, instead of the fluororesin dispersion layer, a fluororesin powder is applied on the photosensitive layer, or a material in which the powder is dispersed is pressed against the photoreceptor to form a release layer for the toner. It is intended to improve the problem. This suppresses a decrease in transfer efficiency and further suppresses wear of the photosensitive layer.
By forming the fluororesin layer on the surface of the photoreceptor, the coefficient of friction is reduced, excellent releasability is exhibited with respect to the toner, and wear of the photoreceptor is suppressed. However, in order to maintain the image quality and the photoreceptor in an appropriate state, it is necessary to manage them under appropriate application conditions. If the fluororesin is applied more than necessary, it causes excessive low wear and causes image flow. In addition, the decrease in the coefficient of friction of the photosensitive layer suppresses the decrease in the film thickness of the photosensitive layer, but on the other hand, slippage of the cleaning blade and developer occurs, resulting in a significant decrease in image density and toner adhesion to the photosensitive member. Occurs, which also causes a decrease in image quality. After applying powdery fluororesin to the photoconductor, the method of smoothing with a blade may cause a bias in the coefficient of friction or a phenomenon in which the powder remains locally fixed, which in turn disturbs the image quality. Happens. Further, when the release layer is formed with a member in which the fluororesin powder is dispersed, the photosensitive layer is easily damaged, the coating layer becomes non-uniform, the charge mobility is different, and the image quality is problematic.
As described above, this method is an effective means for reducing the friction coefficient of the lubricant, but conversely causes a problem.
[0018]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lubricity imparting member device having a structure in which it is difficult to give appearance defects such as scratches to a photoreceptor as compared with the conventional method. Another object of the present invention is to provide an image forming apparatus in which a friction coefficient is set in a suitable range by combining with the lubricity imparting member device, toner cleaning performance is improved, and good image forming performance is obtained even in a high humidity environment. Is to provide.
[0019]
[Means for Solving the Problems]
  According to the present invention, first, there is provided a lubricity imparting member device having a structure in which a lubricity imparting member, a first elastic member, and a second elastic member are laminated in this order.2When a load of 100 g is applied to this area, the first elastic member has a compression rate of 20% or more, and the second elastic member has a compression rate of 1 to 10%.In addition, the first elastic member is a raised member.The lubricity imparting member device is provided.
[0020]
  secondAnd a lubricity imparting member device having a structure in which a lubricity imparting member, a first elastic member, and a second elastic member are laminated in this order, 2 When a load of 100 g is applied to the area, the first elastic member has a compression rate of 40% or more, and the second elastic member has a compression rate of 1 to 10%.A lubricity imparting member device is provided.
[0022]
  FirstthreeAnd the first elastic member is a foam material.twoThe lubricity imparting member device described in 1) is provided.
[0023]
  FirstFourIn addition, the lubricity imparting member is a film having a film thickness of 100 to 400 μmStateThe above-mentioned first to characterized in that it is a fluorine-based resinthreeThe lubricity imparting member device according to any one of the above is provided.
[0024]
  FirstFiveFurther, the working area of the lubricity imparting member is the width of the maximum image forming area in the longitudinal direction of the photosensitive member or a width larger than that.FourThe lubricity imparting member device according to any one of the above is provided.
[0025]
  FirstSixAnd the above firstFiveThe lubricity imparting member device according to any one of the above is provided in a single unit, in combination with another process device, or incorporated in a process cartridge, arranged in contact with the photoreceptor or the coating member, and There is provided an image forming apparatus characterized in that image formation is performed with a static friction coefficient (hereinafter simply referred to as a friction coefficient) between fine papers set to 0.1 to 0.4.
[0026]
  FirstSevenAnd the lubricant application member also serves as a charging member of the contact charging device.SixIs provided.
[0027]
  FirstEightIn addition, the process cartridge includes a photosensitive member, a charging device and a cleaning device, or a photosensitive member and a charging device.FiveWherein the lubricity imparting member device according to any one of the above is disposed so as to be in contact with either the photoconductor or the charging member to form an image.SixOrSevenIs provided.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The lubricity imparting member device of the present invention is composed of a lubricity imparting member and an elastic member, and the elastic member is a first elastic member having a large compressibility and a second compressive ratio smaller than that of the first elastic member. It is comprised by two types of members, an elastic member. By adopting this configuration, foreign matter received by the lubricity imparting member is adequately absorbed and the pressure is dispersed, so that the influence on the photosensitive member is reduced, and even when the photosensitive member or the coating member is scratched. , The influence can be suppressed slightly.
[0029]
Here, the compression rate is defined as follows.
In an environment of 22 to 26 ° C./55 to 65% RH, the elastic member is 2 cm square and the thickness is 10 ± 2 mm.2The change in thickness before and after applying a load of 100 g to the area is measured and calculated by the following formula.
Compression rate = (original thickness−thickness after compression) / original thickness × 100 (%)
[0030]
  In the lubricity imparting member device of the present invention, the first compressing member having a compression rate measured under the same conditions as described above is 20% or more (preferably raising height is about 0.1 to 1 mm). A combination of an elastic member and a second elastic member that is 1 to 5%Is. Thereby, damage can be suppressed to a minimum without giving a scratch to the photosensitive member or the coating member, and as a result, good image quality can be maintained.
[0031]
  In addition, the present inventionotherIn the lubricity imparting member device, the first elastic member having a compression rate of 40% or more when measured under the same conditions as described above is combined with the second elastic member having 1 to 5%.Is. Thereby, even if it gives without giving a scratch to a photoconductor or an application member, damage can be suppressed to the minimum and good image quality can be maintained as a result.
[0032]
Further, in the lubricity imparting member device of the present invention, the foaming material is used for the first elastic member having a compression rate of 40% or more, so that the photosensitive member or the lubricant application member is rubbed and pressed against foreign matter. Can be absorbed and dispersed to achieve uniform contact and prevent or suppress damage to the photoreceptor, and as a result, good image quality can be maintained over a long period of time.
[0033]
Further, in the lubricity imparting member device of the present invention, it is preferable to use a fluorine-based resin, particularly tetrafluoroethylene resin (PTFE: polytetrafluoroethylene resin) as the lubricity imparting member, and thereby a thickness of 100 to 400 μm. It is possible to reduce the friction coefficient of the film and the photoconductor, and to greatly suppress the wear of the photoconductor.
[0034]
In the lubricity-imparting member device of the present invention, the range of the lubricity-imparting member that acts on the photosensitive member or the coating member is at least an image forming area or a length (width) longer than that of the entire image area. It is possible to maintain uniform image formation over the entire area.
[0035]
Further, in the image forming apparatus of the present invention, the lubricity imparting member apparatus is a unit that is installed alone in the image forming apparatus, or is combined with another process unit such as a cleaning device or a charging device. In the image forming apparatus or in the process cartridge, the image forming apparatus is mounted, and image formation is performed with the coefficient of friction of the photosensitive member in the range of 0.1 to 0.4 via the photosensitive member or the coating member. Abrasion of the photosensitive layer can be greatly suppressed and good image forming properties can be maintained.
[0036]
Further, in the image forming apparatus of the present invention, by using the charging member (charging roll) of the contact charging device as the coating member, the image forming apparatus itself can be designed in a compact manner, and on the other hand, the photoreceptor can be further prevented from being damaged. In addition, since the lubricant can be uniformly and efficiently applied, the surface friction coefficient of the photoreceptor can be made more uniform.
[0037]
Furthermore, in the image forming apparatus of the present invention, at least the photosensitive member, the charging device and the cleaning device, or the photosensitive member and the charging device constitute a process cartridge, and the lubricity imparting member device is incorporated therein, thereby reducing the size of the device. In addition, the friction coefficient of the photoconductor can be reduced efficiently and uniformly by forming the lubricity imparting member with the photoconductor while applying the lubricant directly to the photoconductor or via the coating member. It becomes.
[0038]
Next, the copying process used in the present invention will be described.
FIG. 1 shows a conceptual diagram of the copying process. The photoreceptor 101 is charged to about (±) 500 to 1000 V by the charging device 102. In recent years, there are many examples in which a contact charging device that generates less ozone is used in consideration of the environment. The charging device includes a corona charging device in addition to the contact charging device. In the example of FIG. 1, a contact charging device using a charging roll is used.
[0039]
The charging roll of the contact charging device is an elastic body (for example, conductive powder such as carbon, activated carbon fiber, metal powder, etc.) dispersed on a rubber material, acrylic resin, etc. (Processed around 50 degrees), 10Ten-1013A material such as hydrin rubber having a resistance of about Ω · cm molded into a single layer or a laminate is used, and a direct current voltage (±) of about 1000 to 2000 V or alternating current (frequency 50 Hz to 10 kHz) is superimposed. A voltage is applied, and a charge is applied to the photoreceptor 101.
[0040]
An organic photoreceptor (OPC) is used for the photoreceptor 101. The configuration of the photoconductor 101 differs depending on whether it is negatively charged or positively charged, but generally has a configuration as shown in FIGS. 2 (a) to 2 (d).
In addition to aluminum (Al) and stainless steel (SUS), the photosensitive member 101 uses a cylindrical conductive support 1 made of a resin, paper product, glass, or the like subjected to conductive treatment. The conductive support 1 has a thickness of 2 to 20 μm in order to prevent charge injection from the conductive support and to suppress reflection of the light image.210 in which fine particles of a metal oxide such as6-10TenAn undercoat layer 2 having a medium resistance of about Ω · cm is preferably formed.
The photosensitive layer formed on the undercoat layer 2 varies depending on the process used (analog system, digital system, + charging, −charging), and has a configuration as shown in FIGS. 2 (a) to 2 (d).
[0041]
2A is a single layer type in which a photosensitive layer 5 in which a charge transport material and a charge generation material (such as an azo pigment or a metal phthalocyanine type) are integrated is formed on the undercoat layer 2, and FIG. Without forming the pulling layer 2, the charge generation layer 3 having a thickness of 0.15 to 0.2 μm is formed directly on the conductive support 1.15-1017Charge transport with a thickness of 10-50 μm with increased hole mobility by donor using polycarbonate resin (A type, C type, Z type, etc.) or polyolefin resin with volume resistance of about Ω · cm as binder resin FIG. 2C shows a function-separated type photoreceptor in which the charge generation layer 3 and the charge transport layer 4 are formed in this order on the undercoat layer 2. d) is a photoreceptor in which a protective layer 6 is further formed on the charge transport layer 4. In the case of positive charging, the configuration shown in FIG. 2A is often used. In the case of negative charging, the photoconductors shown in FIGS. 2B to 2D are often used.
[0042]
After a positive or negative charge is applied (charged) to the photoconductor, image exposure 103 is performed on the surface of the photoconductor 101.
In the case of an analog copying machine, an original image irradiated with an exposure lamp such as a halogen lamp or a fluorescent lamp is projected by visible light. In the case of a digital copying machine, an original image read by a CCD (charge coupled device) is 630 to 630. It is converted into a 780 nm LD or LED digital signal and imaged on the photoreceptor 101.
[0043]
By image formation, charge separation is performed in the photosensitive layer, and a latent image is formed on the photosensitive member. The photosensitive member on which the latent image has been formed according to the document is developed by the developing device 104 with a one-component or two-component developer, and the document image is visualized (toner image).
[0044]
After the toner image on the photosensitive member is transferred to the copy sheet 109 by the transfer device 105, the copy sheet is separated from the transfer device 105 and sent to the fixing device 108 to be a hard copy. On the other hand, after the toner image is transferred to the photoconductor 101, after the residual toner is cleaned by the cleaning device 106, the lubricant is applied to the photoconductor 101 by the lubricity imparting member device 200, and the surface friction coefficient of the photoconductor 101 is preferable. After being reduced and maintained to a certain level, the residual latent image is erased by the static eliminator 107, and the series of copying processes is completed.
[0045]
Next, problems in the copying process will be described.
Examples of devices that are put into practical use as means for applying a charge (charging) to the photoreceptor include a corona charging method (wire, sawtooth electrode, etc.) and a contact charging method (conductive brush, charging roll, etc.).
The charging device is applied with a DC voltage or a DC voltage (AC superimposed DC voltage) superimposed with an alternating current (50 Hz to 10 kHz) that can obtain more charging stability in high and low humidity environments, and the surface potential of the photoreceptor is (±) about 500 to 1000V is set.
[0046]
When the photosensitive member is charged by the charging device, there is a discharge phenomenon more or less, and as pointed out above, ozone (OThree) And nitrogen oxides (NOx) are generated.
When this corona product acts on the photoreceptor, the electrophotographic characteristics are deteriorated, the surface resistance of the photosensitive layer is lowered, the resolution is lowered, and the entire image is liable to flow. Further, the corona product adheres to the photoreceptor and further penetrates into the photosensitive layer, thereby increasing the coefficient of friction of the photosensitive layer, promoting the wear of the photosensitive layer, and shortening the life of the photoreceptor.
[0047]
Since the contact charging method operates at a voltage as low as about 1/3 to 1/5 that of the corona charging method, the amount of ozone generated is about 1/100 to 1/200 of the corona discharge method compared to the corona charging method ( 0.1 ppm or less) and nitrogen oxides are as small as about 1/50 to 1/100 (0.01 ppm or less), which is advantageous in terms of the environment. However, since it is a phenomenon close to the photoreceptor, the generated corona product acts on the photoreceptor almost 100%.
On the other hand, in the case of the corona discharge method, since the photosensitive member and the charging device are separated from each other, it is necessary to increase the applied voltage to about 3 to 5 times that of the contact charging device, and the generation of corona products is extremely large. However, since there is a space, the corona product is dissipated and the exhaust device is easily actuated. Therefore, the damage to the photosensitive member may be equal between the contact charging device and the corona charging device, or rather less in the corona discharge method.
[0048]
Among the generated corona products, NOx adheres to the surface of the photosensitive layer and becomes nitric acid by moisture in the atmosphere, reducing the surface resistance, causing a reduction in resolution, and in severe cases leading to image flow. Furthermore, since it has viscosity, it is easy to adsorb foreign matters such as toner and paper dust, and the charging roll is contaminated and causes soiling.
On the other hand, ozone has a bleaching action and a strong oxidizing action as chemical properties, so the photoconductor is discolored (yellowing, decolored, etc.), the intermolecular bonds of the constituent materials of the photoconductor are broken, and the photoconductor Reduces transport capacity and photosensitive function.
[0049]
By the way, in the production of the organic photoreceptor, a monophenol compound such as 2,6-di-t-butyl-p-cresol or butylated hydroxyanisole is used for the photosensitive layer (charge transport layer), if necessary. Bisphenol compounds such as' -methylene-bis- (4-ethyl-6t-butylphenol), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy In some cases, an antioxidant or an oxidation inhibitor such as a high molecular phenol compound such as (benzyl) benzene, hydroquinones, and organic phosphorus compounds, or a plasticizer is added in an amount of 1 to 20% by weight. However, the higher the durability of the photoconductor, the more difficult it is to avoid the effects of ozone and other effects on the photosensitive layer, and it continues to act on the surface of the photosensitive layer even after the charging device is stopped. You may be invited.
[0050]
Since organic photoreceptors are subject to wear, while the photoreceptor is rotating, the deteriorated outermost layer is scraped off and a new surface is created, so there is an advantage that image deterioration can be avoided. If it is larger, an image forming apparatus having a high process speed requires frequent replacement of the photosensitive member.
[0051]
Although the corona product has been described as the main factor substance, such as increasing the coefficient of friction and decreasing the photoreceptor characteristics and image quality, there are other effects due to adhesion to the photoreceptor surface. Factors that give toner include toner constituents (such as charge control agents) carrier constituents (such as coating agents), binders contained in paper, photosensitive layer scraping, and gas components emitted from the fixing device. is there.
[0052]
Next, a method for stabilizing the image quality by suppressing photoconductor wear will be described. The abrasion of the photosensitive layer is caused by the following action. That is, the corona product causes chemical deterioration of the photosensitive layer, and the contact resistance of the blade is increased due to the adhesion of the corona product and the toner composition, so that a lump of toner, magnetic powder or the like is caught between the blades and is likely to be scratched. It is.
[0053]
For this reason, in order to suppress wear of the photosensitive layer, it is the most effective means to reduce the friction coefficient of the surface layer of the photosensitive member. As a means for lowering the coefficient of friction of the photoreceptor, a direct method in which a lubricity imparting member is directly applied to the photoreceptor, and an indirect method in which a lubricant imparting member is acted on the coating member and a lubricant is imparted from the coating member to the photoreceptor. There is.
In the direct method, the lubricity imparting member is brought into contact directly with the photoconductor, and in the indirect method, the lubricity imparting member is brought into contact with the coating member to reduce the coefficient of friction of the photoconductor. Since there is a rubbing action, if the contact with the lubricity imparting member is strong or a hard member is used, there is a high possibility of scratching or wearing the photosensitive member or coating member, which affects the image quality. .
[0054]
Therefore, when the lubricity imparting member comes into contact with the photosensitive member or the coating member, it is necessary to form a nip with a soft pressure that does not cause scratches and to make contact evenly. Therefore, in order to form the nip necessary for the photoreceptor or coating member evenly and uniformly, the lubricity imparting member and the lubricity imparting member are in contact with the photoreceptor or coating member. It is important to have a structure that sometimes comes into contact with the software and absorbs the influence of foreign matter such as toner, and disperses the biting force on the photoreceptor or application member.
[0055]
A production example of the lubricity imparting member device will be described with reference to FIGS.
FIG. 3 shows an example of the configuration of a lubricity imparting member device useful for reducing the friction coefficient by directly acting on the photosensitive member. The image forming apparatus can be used alone (see FIG. 5), or attached to the cleaning device 106 (see FIG. 6) or the side surface (cleaning device side) of the charging device.
FIG. 4 shows an example of the configuration of a lubricity imparting member device that acts on the coating member to indirectly reduce the coefficient of friction of the photoreceptor. In terms of content, the configuration is almost the same as in FIG. An example in which the charging roll is used as an application member is shown in FIG.
[0056]
The configuration of the lubricity imparting member device of FIG. 3 will be described. The base 201 is made of stainless steel (SUS), iron plate, aluminum (Al) plate or the like having a thickness of about 0.3 to 2 mm. A first elastic member 203 and a second elastic member 202 are overlaid and pasted on the base body 201. In the figure, 204 is an auxiliary member, and 205 is a lubricity imparting member.
The first elastic member 203 must have a higher compression rate than the second elastic member 202.
[0057]
  One of the first elastic members 203 is a raised member having a raised height of about 0.1 to 1 mm (the thickness of the entire raised member is about 1 to 2 mm). The raised members include special leathers such as flannel, velvet, polyester or polyurethane, and a commercially available product can be used. If possible, a highly recoverable member is desirable for the raised portion.
  This raised member is 20% or more measured by the compression rate measurement method.Becauseis there. 20%Less thanCompressionAt a rateWhen it exists, the effect of absorption and dispersion with respect to foreign matters is insufficient, and scratches are likely to occur.
[0058]
  First elastic memberThe other one ofThe elastic member having a compression rate of 40% or moreUsedUsed. In particular, the foam material is effective for dispersion and absorption of pressure against foreign matter, and has a thickness of about 2 to 6 mm and a density of 20 to 50 kg / m.3, Tensile strength 0.5-1.5kg / cm2Foam (sponge form) exhibiting characteristics of a degree is almost included in the compression ratio.
[0059]
  A member harder than the first elastic member is used for the second elastic member 202.
  An elastic member having a compression rate of 1% or more and 10% or less is used. Compression rate is 1%Less thanThen, it becomes too hard and the effect of the first elastic member cannot be utilized. 10%BeyondThen, when the lubricity imparting member comes into contact with the photosensitive member, it is too soft, so that a suitable contact pressure cannot be applied, and a predetermined friction coefficient cannot be set. Preferably, the compression rate is 2% to 5%, and the density is 50 to 60 kg / m.3, Tensile strength 1kg / cm2An elastic member of foam (sponge form) showing front and rear characteristics is substantially included in the compression rate.
  The thickness of the second elastic member is also selected according to the required specifications of about 2 to 6 mm.
[0060]
There are many types of lubricity imparting members 205 for imparting lubricant to the photoreceptor 101, and film-type fluororesins are particularly preferred, and among these, tetrafluoroethylene resin (PTFE: polytetrafluoroethylene) is preferred. Is preferred.
Tetrafluoroethylene resin (PTFE: polytetrafluoroethylene) is easily transferred to the mating member by light rubbing among various fluororesins, and the friction of the rubbing mating partner (herein, a photoconductor or a coating member). Because it has excellent lubricity to reduce the coefficient to 0.1 or less, and the particles are very fine, it forms a very thin film when transferred to the photoreceptor, and there is no image quality degradation from optical properties, and it is solid, It is easy to handle.
[0061]
The film thickness of the film-like lubricity imparting member 205 is preferably 100 to 400 μm. When the film thickness is less than 100 μm, the flexibility is high and scratches are difficult to be given, but the durability is insufficient and frequent replacement is required. On the other hand, if the thickness is greater than 400 μm, the greater the thickness is, the less flexibility is provided, so that even the effect of the first elastic member cannot be absorbed and the possibility of damaging the photoreceptor increases. Usually, 200 to 300 μm is appropriate.
Products such as Nichias, Daikin Kogyo, Nitto Kogyo, and 3M are available for this lubricity imparting member.
[0062]
Since the auxiliary member 204 is used as a member for maintaining the elasticity of the first elastic member and maintaining the deformation as much as possible, a range in which the functions of the lubricity imparting member and the first and second elastic members are maintained. It is necessary to use. The auxiliary member 204 is made of polyethylene terephthalate (PET), polycarbonate resin plate, phosphor bronze plate or the like having a thickness of about 0.1 to 0.5 mm, and the lubricity imparting member 205 is bonded to the auxiliary member 204. The adhesive layer should not be used in the vicinity of the portion in contact with the photoreceptor. However, the auxiliary member is not necessarily required depending on the material used and the bonding method.
[0063]
Then, the structure of the lubricity provision member apparatus of FIG. 4 is demonstrated. FIG. 4 shows an example of another lubricity imparting member device 200 for reducing the coefficient of friction of the photoreceptor via the coating member. It is compact to use a charging roll as the coating member, and the friction coefficient is easy to control. The material of the charging roll is made of rubber or acrylic as mentioned above from the viewpoint of durability, but the charging member is more wear resistant than the photoconductor, so the contact pressure is set slightly higher. can do.
In the indirect method, it is necessary to supply a sufficient amount of lubricant since the lubricant is once applied to the application member and then applied to the photoreceptor. The transfer amount of the lubricant to the photoconductor includes the diameter of the photoconductor and the coating member, the copying speed (linear speed), the cleaning interval of the cleaning member attached to the charging roll (see FIGS. 6 and 7), the image density of the document, etc. Depends on.
[0064]
By mounting the lubricity imparting member on the image forming apparatus under appropriate conditions, the coefficient of friction of the photosensitive member is set to an appropriate range (0.1 to 0.4). As a result, the corona product and residual toner adhering to the surface of the photosensitive member are easy to clean, and the residual corona product adhering to the outermost surface of the photosensitive layer and toner components are harmful to image quality. Since the substance is lightly scraped according to the level of the coefficient of friction, the image quality is moderately maintained, and the resistance of the blade and developer to the photosensitive member is also reduced, so wear is also suppressed.
[0065]
FIG. 8 shows the relationship between the friction coefficient (average value of 1,000 to 50,000 sheets) and the abrasion amount of the photosensitive layer when copying 50,000 sheets.
A preferable range of the coefficient of friction of the photoreceptor is 0.1 to 0.4. This value is almost dependent on the image quality. When the friction coefficient is about 0.1, contaminants such as the corona product adhering to the surface of the photoconductor are not removed due to slipping, and the value is as high as about 90% RH. In a humid environment, image flow is likely to occur, and when it exceeds 0.4, the wear of the photosensitive layer is promoted, and the life of the photoreceptor is shortened due to deterioration of the photosensitive characteristics.
[0066]
The coefficient of friction of the photoreceptor is more preferably set to be in the range of 0.2 to 0.3 from the stability of the image and the wear amount of the photosensitive layer. However, if a charging device (for example, an induction charging device, a contact or non-contact charging device using an activated carbon fiber member) that generates almost no corona product such as ozone is used, it is about 0.15 or less. Even if it is a friction coefficient, it is also possible to give practicality enough, and further high durability can be achieved.
[0067]
The coefficient of friction depends on the contact pressure and nip. Normally, the nip should be formed around 2 mm, and if the contact pressure is about 10 to 20 g according to the measurement method described later, it can cope with the medium speed machine of 20 to 40 cpm, and the number of copies more than that This image forming apparatus can be dealt with by making a structure so as to earn a little more nip.
[0068]
It is desirable to set the working area of the lubricity imparting member at least in the image forming area or with a width exceeding it. That is, when the setting is made in the image forming area, a step is generated in the photoconductor scraping, and therefore, there is a risk that the smearing is likely to occur as copying progresses in a portion outside the lubricity imparting member that has been scraped off. Thus, preferably, the width of the lubricity imparting member is set in an area exceeding the image forming area in consideration of misalignment of the copy paper.
[0069]
Next, the attachment position of the lubricity imparting member device will be described.
The lubricity imparting member device 200 having the form shown in FIG. 3 may be any position on the photosensitive member as long as it does not impede image formation. However, the cleaning device 106 and the charge eliminating lamp 107 or the charging device 102 are preferable. (See FIGS. 5 and 6). This is because, at this position, even if the image forming apparatus is in operation, it can always operate regardless of image formation. The installation method may be used alone or in combination with other process devices (cleaning device, charging device, etc.).
[0070]
The cleaning device can be used for either a single blade cleaning device or a device using a cleaning brush. The fluororesin is shaved into fine powder, but the fine powder may stick to the photoreceptor as a lump. Therefore, the black solid image has white spots and affects the image quality. As a means of avoiding this phenomenon, the friction coefficient is maintained at an appropriate value by using a brush material (for example, loop brush (SA-7, acrylic)) having a high scraping effect and good cleaning property. However, it is possible to achieve a balance with wear.
[0071]
The lubricity imparting member device having the form as shown in FIG. 4 is installed in such a manner as to abut on a charging roll of a contact charging device as an application member. Any position may be used. Preferably, the contact pressure is set so as not to impair the rotation of the charging roll on the lower side (outlet side) of the charging roll cleaning member. The charging roll cleaning member is desirably operated intermittently every 50 or 100 sheets. This is because the lubricant once applied to the charging roll is deleted by the cleaning member, so that the amount transferred to the photoreceptor is reduced, and it is difficult to obtain a predetermined friction coefficient.
[0072]
The lubricity imparting member device alone or in combination with other process devices is installed as a replacement part in the image forming apparatus, or at least a process cartridge comprising a photoreceptor and a charging device, or a photoreceptor, a charging device and a cleaning device Can be incorporated into.
[0073]
In addition, the friction coefficient described in the text shall be calculated by the following measurement method.
A photoconductor for measurement is fixed, and a high-quality paper cut to a thickness of 85 μm, a width of 30 mm, and a length of 290 mm is prepared as a belt. The high-quality paper is placed on the photoconductor, and a 100 g weight is placed on one end of the belt. , Attach a digital force gauge that weighs to the other end, slowly pull the digital force gauge, read the weight when the belt starts moving, and calculate the coefficient of static friction using the following formula.
μs = 2 / π × ln (F / W)
Where μs: static friction coefficient, F: reading load
W: Weight of weight π: Circumference ratio
Related matters about this measuring method (Euler belt method) are also described in JP-A-9-166919.
[0074]
Further, the contact pressure described in the text is defined as follows.
Insert a high-quality paper (belt) 100 mm in length, 30 mm in width, and 85 μm in thickness between the photoconductor or application member and the lubricity imparting member, and read the maximum value when pulled out by the digital force gauge, This value is defined as the contact pressure. The unit is represented by g.
[0075]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
[0076]
(Evaluation methods)
As an apparatus for confirming the effect, MF200 machine, MF3500 machine (Brush cleaning method using SA-7 (acrylic, manufactured by Toray Industries, Inc.) as a brush material was prepared, both of which are Ricoh electrophotographic copying machines) Evaluation was performed by the following methods and conditions. The rotation speed of the brush is 330 rpm and rotates in the counter direction.
The evaluation method is continuous feeding of A4 size lateral feed, image evaluation with a specified original every 1000 to 5000 sheets, measurement of the friction coefficient by the above method, and Fischer's eddy current film thickness for every 10,000 sheets Using a meter (model MMS), film thickness measurement was added to the above measurement items, and effects were confirmed.
The evaluation environment is 22-24 ° C./60-70% RH and 30 ° C./90% RH.
[0077]
(Photoconductor production method)
The photoreceptor used for the evaluation was prepared by the following procedure.
Undercoat layer coating solution, charge generation layer coating solution, and charge transport layer formulation for aluminum drums with a thickness of 1.2 mm, φ30 mm (for MF200) or φ60 mm (for MF3500), and length of 340 mm By sequentially applying the coating liquid and drying each layer, an undercoat layer having a thickness of 3.5 to 4 μm, a charge generation layer having a thickness of 0.2 to 0.25 μm, and a charge having a thickness of 24 to 28 μm Each of the transport layers was formed to produce an electrophotographic photoreceptor. In addition, all the following parts are parts by weight.
[0078]
[Coating liquid for undercoat layer]
Figure 0003865555
[0079]
[Coating liquid for charge generation layer]
5 parts of oxotitanium phthalocyanine pigment
Polyvinyl butyral (UCC: XYHL) 2 parts
80 parts of tetrahydrafuran (THF)
[0080]
Figure 0003865555
[Chemical 1]
Figure 0003865555
100 parts methylene chloride
A few drops of methylphenyl silicone oil (50cs)
[0081]
Example 1
A soft sponge EP having a size of 5 mm × 310 mm × 8 mm and a compression rate of 2% is used as the second elastic member, and a velvet having a size of 310 mm × 8 mm and a compression rate of 40% and a raising height of 1 mm is the first elastic member. These were laminated with a double-sided tape to produce a two-piece elastic member.
This was bonded to an SUS plate having dimensions of 0.3 mm × 310 mm × 17 mm using an adhesive.
Next, a PET film cut to a size of 0.2 mm × 310 mm × 11 mm as an auxiliary member is attached to the front surface of the velvet and the base with double-sided tape so that it protrudes from the lower end of the base, and finally, 0.2 mm using double-sided tape. A × 310 mm × 8 mm PTFE film (manufactured by Nichias, # 9001) was stretched on an auxiliary member having a width of 4 mm to produce a lubricity imparting member device as shown in FIG. The lubricity imparting member device thus produced was attached to the cleaning device portion of the MF3500 machine using a spacer, and the contact pressure with the photosensitive member was set to 15 to 18 g for evaluation.
[0082]
(Example 2)
Non-woven fabric (made of polyester) having a size of 8 mm × 310 mm as a first elastic member, a compression rate of 33% and a raised height of about 0.3 mm, and a PTFE film cut to a size of 0.3 mm × 310 mm × 11 mm as an auxiliary member ( A lubricity imparting member device was fabricated in the same manner as in Example 1 except that Nichias Co., Ltd. # 9001) was used. This was mounted on an MF3500 machine, and the same evaluation as in Example 1 was performed.
[0083]
(Example 3)
PTFE cut into dimensions of 8 mm x 310 mm as the first elastic member and a compression rate of 21% (mixed polyester fiber and polyurethane fiber, manufactured by Toray Industries, Inc.) and 0.3 mm x 310 mm x 11 mm as the auxiliary member A lubricity imparting member device was prepared in the same manner as in Example 1 except that a film was used. The same evaluation was carried out under the same conditions as in Example 1.
[0084]
These evaluation results are shown in Table 1.
In the lubricity imparting member devices using the elastic members having compression ratios of 15% and 20% shown in Examples 1 and 2, there was almost no problem with the effect of scratches and halftone images, and the wear of the photosensitive layer was small. In Example 3, about two scratches appeared slightly in the black solid image, and some unevenness occurred. However, there was no abnormality in the background of the character image.
[0085]
[Table 1]
Figure 0003865555
[0086]
(Example 4)
A second elastic member made of a soft sponge EP having a size of 5 mm × 310 mm × 8 mm as in Example 1 and a compression rate of 2%, and a urethane foam RS having a size of 2 mm × 310 mm × 7 mm and a compression rate of 65% (Inoac Corporation) A first elastic member made of the same material, an auxiliary member similar to that described in Example 1, a PTFE film (thickness of 300 μm), and a substrate having the same dimensions as in Example 1, and a lubricity imparting member device Was made. This was fixed using a spacer at the cleaning blade portion of the MF3500 machine so that the contact pressure with the photoconductor was 15 to 18 g. Evaluation similar to Example 1 was implemented for this.
[0087]
(Example 5)
A lubricity imparting member device was produced in the same manner as in Example 4 except that the first elastic member was changed to EMO (manufactured by INOAC) having a compression rate of 60%, and the same evaluation was performed.
[0088]
Example 6... Reference examples)
  The lubricity imparting member device was changed in the same manner as in Example 4 except that the first elastic member was changed to ECA (made by INOAC) having a compression rate of 27% and the thickness of the lubricity imparting member (PTFE) was changed to 200 μm. The same evaluation was performed.
[0089]
  These results are shown in Table 2. In Examples 4 and 5 using the first elastic member having a compression rate of 65% and a compression rate of 60%, both were not affected by scratches, and the photosensitive layer was less worn and good. Example 6(Reference example)In the lubricity-imparting member device using the first elastic member having a compression rate of 27%, the scratch is slightly black with a few white streaks on the black solid image, and the halftone image shows a little unevenness in the high humidity environment. There were no black streaks in the area, and it was generally good.
[0090]
[Table 2]
Figure 0003865555
        Note) Example 6 is a reference example.
[0091]
(Example 7)
A second elastic member made of urethane foam LE-20 (manufactured by Inoac Co., Ltd.) having a compression rate of 2% and made of 2 mm × 310 mm × 5 mm, a first made of a nonwoven fabric having a compression rate of 33% and a size of 310 mm × 5 mm The elastic member is similar to FIG. 3 using an auxiliary member made of PET having a thickness of 0.1 mm, a lubricity-imparting member having a thickness of 300 μm, and an aluminum substrate having a thickness of 0.5 mm processed into a U-shape. A lubricity imparting member device was prepared. This was attached to the metal plate of the blade cleaning device of MF200 so as to contact the charging roll, and the contact pressure with the charging roll was set to 40 to 45 g. This was evaluated in the same manner as in Example 1.
[0092]
(Example 8)
A lubricity imparting member device was produced in the same manner as in Example 7 except that the first elastic member was changed to a special one with a compression rate of 45%, and this was attached to the MF200 machine in the same manner as in Example 7 and the same evaluation was performed. did.
[0093]
Example 9
A 1.2 mm × 310 mm × 15 mm aluminum plate is prepared as a base, and the same member as in Example 8 is used to produce a lubricity imparting member device similar to that shown in FIG. 4 and lubricate the metal part of the charging roll unit. The property-imparting member was fixed with a double-sided tape, and the contact pressure was set between 45 and 55 g for evaluation. In carrying out this, a photosensitive unit from which a cleaning member provided with a charging roll was removed was used.
[0094]
These results are shown in Table 3.
There was no occurrence of scratches in Examples 7 to 9. Regarding the image unevenness, the problem was small in both Examples 7 and 8, but the unevenness occurred slightly in Example 9. Further, since the friction coefficient was high, the photosensitive layer was a little more worn than in Examples 7 and 8. There was no problem with resolution even in high humidity environments.
[0095]
[Table 3]
Figure 0003865555
[0096]
(Comparative Example 1)
Evaluation was performed with an MF3500 machine without mounting the lubricity imparting member device.
[0097]
(Comparative Example 2)
Without using the first elastic member, the second elastic member has a size of 5 mm × 310 mm × 8 mm and a compression rate of 2%, soft sponge EP, the lubricity imparting member has a thickness of 300 μm, and the base has a size of 0.3 mm × Using a 310 mm × 17 mm SUS plate, the lubricity imparting member device shown in FIG. 3 was produced. A spacer was used for the blade cleaning part of the MF3500 machine, and screws were attached so that the contact pressure with the photosensitive member was about 14 to 18 g, and the same evaluation as in Example 1 was performed.
[0098]
(Comparative Example 3)
In place of the 300 μm thick PTFE shown in Comparative Example 2, a similar lubricity imparting member device was prepared by using PTFE having a thickness of 500 μm, and the same evaluation was performed.
[0099]
(Comparative Example 4)
Prepare a soft sponge EP of 5 mm x 310 mm x 10 mm with a compression rate of 2% as the second elastic member, PTFE with a thickness of 300 μm as the lubrication imparting member, and an aluminum plate of 1.2 mm x 310 mm x 15 mm as the base to impart lubricity A member device was produced. This was attached to the metal part of the charging roll of the MF3500 machine so that the contact pressure showed a value of around 45 g. Using this, the same evaluation as in Example 1 was performed.
[0100]
These results are shown in Table 4.
In Comparative Example 1, there was no problem in image quality, but the coefficient of friction showed a value of 0.5 or more, and the abrasion of the photosensitive layer was 50,000 sheets, which averaged 5.6 μm.
In Comparative Example 2, the generation of scratches at 50,000 sheets was small, but there was a deeper scratch, and several black streaks and strips were generated on the background.
In Comparative Example 3, since the PTFE was set to 500 μm, a portion where the contact with the photoconductor was locally high occurred, and scratches were concentrated in that portion, and black streaks were observed.
In Comparative Example 4, the lubricity-imparting member was brought into contact with the charging roll, but the nip was insufficient and the friction coefficient was increased. Moreover, the application of the lubricant was insufficient, and a streak pattern was generated.
[0101]
[Table 4]
Figure 0003865555
[0102]
(Comparative Example 5)
Second elastic member made of soft sponge EP having a compression rate of 2% and having a size of 5 mm × 250 mm × 8 mm without using the first elastic member, and an auxiliary member made of a PET film having a size of 0.1 mm × 250 mm × 11 mm , A base made of SUS having dimensions of 0.3 mm × 310 mm × 20 mm, and a lubricity-imparting member made of PTFE (manufactured by Nichias, # 9001) having dimensions of 300 μm × 250 mm × 9 mm, respectively. A lubricity imparting member device was produced. This was matched with the cleaning blade unit of the MF3500 machine and evaluated by attaching 75,000 sheets using a spacer. The contact pressure with respect to the photosensitive member was set to 14 to 18 g. Evaluation similar to Example 1 was performed using this.
[0103]
(Comparative Example)
  A first elastic member made of velvet having a compression rate of 40% and a size of 250 mm × 8 mm and a raised height of 1 mm, and a second elastic member made of soft sponge EP having a compression rate of 2% and a size of 5 mm × 250 mm × 8 mm An auxiliary member made of 0.1 mm × 250 mm × 11 mm PET and a lubricity imparting member made of PTFE (thickness 300 μm) were used, respectively, to produce a lubricity imparting member device equivalent to FIG. This was evaluated in the same manner as in Comparative Example 5.
[0104]
  The results are shown in Table 5. Comparative Example 5,Comparative exampleIn this case, the width of the copy paper is 297 mm (the effective image forming area is 293 mm), and the width of the lubricity imparting member is as narrow as 250 mm. A level difference of 5 to 6.2 μm was generated, cleaning was poor, charging was inadequate, and both sides were thinly soiled. In Comparative Example 5, a slight streak pattern due to uneven contact was further generated in the halftone image.
[0105]
[Table 5]
Figure 0003865555
[0106]
【The invention's effect】
  Claims 1 to3The lubricity-imparting member device of the present invention described in the following is a base member, a first elastic member, a second elastic member, and a lubricant as members that contact the photosensitive member or the coating member and reduce the friction coefficient of the photosensitive member. 1st elastic member comprised by the property provision memberAs thatThe compression ratio of 20% or moreNapping members or elastic members with a compression rate of 40% or more, Second elastic memberAs thatBy maintaining a lubricity imparting member device using a member having a compression ratio of 1 to 10%, the photosensitive member and the coating member are not damaged during rubbing, so that uniform image quality is maintained. Became possible.
[0107]
  BookThe lubricity imparting member device of the invention isIn particularBy using a raised member having a compression rate of 20% or more as the first elastic member in contact with the lubricity imparting member and using an elastic member having a compression rate of 10% or less and 1% or more as the second elastic member, the photosensitive member or Since the contact with the coating member is uniform and soft, and the local pressure is absorbed even in the presence of foreign matter, it is possible to avoid scratching the photoreceptor or the coating member as much as possible. Long-term stability of the photoreceptor and the coating member could be maintained.
[0108]
  BookThe lubricity imparting member device of the invention isIn particularBy using an elastic member (preferably a foam material) having a compression rate of 40% or more as the first elastic member and using an elastic member having a compression rate of 10% or less and 1% or more as the second elastic member. Since the contact becomes soft and the influence of foreign matter is dispersed, the photosensitive member and the coating member are not easily damaged by scratches, etc., and the damaged damage can be kept within a narrow range, so that good image quality is maintained. In addition, it is possible to extend the life of the photosensitive member or the coating member.
[0109]
  Claim4In the lubricity imparting member device of the present invention described in 1), by selecting a tetrafluoroethylene resin as the lubricity imparting member, the friction coefficient of the photoreceptor can be lowered even with a light pressure, and a film of 100 to 400 μm can be obtained. By making it thick, it is possible to suppress damage to the photosensitive member or the coating member as much as possible, and it is possible to stably maintain the image quality as well as the durability of the photosensitive member or the coating member.
[0110]
  Claim5The lubricity-imparting member device according to the present invention described in the present invention is configured such that the range in which the lubricity-imparting member acts is equal to or slightly longer than the maximum image forming area in the longitudinal direction of the photosensitive member. Since no step is sometimes generated, uniform image formation can be maintained over the entire copy image without causing background contamination or density unevenness.
[0111]
  Claim6The image forming apparatus according to the present invention described in (1) can be installed in a narrow area because the lubricity imparting member according to the present invention is extremely compact. Also, the installation method can be installed either alone or in combination with other process apparatuses, and can be installed in the image forming apparatus or in a process cartridge and stored in the image forming apparatus.
[0112]
  Claim7In the image forming apparatus according to the present invention described above, the coating member can be designed compactly by using a charging member (charging roll) of a contact charging device, and a predetermined friction coefficient can be controlled. Further, since the friction coefficient of the charging roll is lowered, contaminants such as toner and corona products are less likely to adhere, and the cleaning property is improved, so that an image with good S / N image quality can be maintained. did it.
[0113]
  Claim8The image forming apparatus of the present invention described in (1) comprises at least a photosensitive member, a charging device and a cleaning device, or a photosensitive member and a charging device as a process cartridge mounted on the image forming device and provided with a lubricity imparting member device. Is effective in terms of handling. As a result, the contact of the lubricity-imparting member is stable, and the lubricant can be stably supplied to the photoreceptor, so that the durability of the photoreceptor and the coating member is maintained as well as the lubricity-imparting device. As a result, the image quality can be maintained stably.
[Brief description of the drawings]
FIG. 1 is a schematic view of a copying process of the present invention incorporating a lubricity imparting member device.
FIG. 2 is a schematic view showing a layer structure of a photoreceptor used in the present invention.
FIG. 3 is a schematic view illustrating a lubricity imparting member device.
FIG. 4 is a schematic view illustrating another lubricity imparting member device.
FIG. 5 is a schematic view illustrating attachment of the lubricity imparting member device shown in FIG. 3 alone to a corona charging type image forming apparatus.
6 is an explanatory view showing an example in which the lubricity imparting member device shown in FIG. 3 is attached to a blade cleaning device. FIG.
7 is an explanatory view showing an example in which the lubricity imparting member device shown in FIG. 4 is attached to an application member (charging roll). FIG.
FIG. 8 is a graph showing the relationship between the coefficient of friction of the surface layer of the photosensitive layer (average value from 1,000 to 50,000 sheets) and the photosensitive layer wear amount (wear amount after 50,000 sheets).
[Explanation of symbols]
1 Conductive support
2 Undercoat layer
3 Charge generation layer
4 Charge transport layer
5 photosensitive layer
6 Protective layer
101 photoconductor
102 Charging device
103 Image exposure system
104 Developing device
105 Transfer device
106 Cleaning device
107 Static eliminator
108 Fixing device
109 copy paper
200 Lubricity imparting member device
201 substrate
202 second elastic member
203 1st elastic member
204 Auxiliary member
205 Lubricity imparting member

Claims (8)

潤滑性付与部材、第１の弾性部材、第２の弾性部材の順に積層される構造を有する潤滑性付与部材装置であって、４．７５ｃｍ２のエリアに１００ｇの荷重を掛けたとき、第１の弾性部材が２０％以上の圧縮率を有し、かつ第２の弾性部材が１〜１０％の圧縮率を有し、しかも該第１の弾性部材が起毛部材であることを特徴とする潤滑性付与部材装置。A lubricity imparting member device having a structure in which a lubricity imparting member, a first elastic member, and a second elastic member are laminated in this order, and when a load of 100 g is applied to an area of 4.75 cm 2 , the first an elastic member is more than 20% compression rate, and the second elastic members have a 1-10% of the compression ratio, yet the first elastic member and said raising member der Rukoto Lubricity imparting member device. 潤滑性付与部材、第１の弾性部材、第２の弾性部材の順に積層される構造を有する潤滑性付与部材装置であって、４．７５ｃｍ ２ のエリアに１００ｇの荷重を掛けたとき、第１の弾性部材が４０％以上の圧縮率を有し、かつ第２の弾性部材が１〜１０％の圧縮率を有することを特徴とする潤滑性付与部材装置。 A lubricity imparting member device having a structure in which a lubricity imparting member, a first elastic member, and a second elastic member are laminated in this order, and when a load of 100 g is applied to an area of 4.75 cm 2 , the first The lubricity imparting member device according to claim 1, wherein the elastic member has a compressibility of 40% or more, and the second elastic member has a compressibility of 1 to 10% . 第１の弾性部材が発泡材であることを特徴とする請求項２に記載の潤滑性付与部材装置。The lubricity imparting member device according to claim 2 , wherein the first elastic member is a foam material. 潤滑性付与部材が膜厚１００〜４００μｍのフィルム状フッ素系樹脂であることを特徴とする請求項１〜３のいずれかに記載の潤滑性付与部材装置。The lubricity imparting member device according to any one of claims 1 to 3 , wherein the lubricity imparting member is a film-like fluororesin having a film thickness of 100 to 400 µm. 潤滑性付与部材の作用領域が、感光体の長手方向で最大画像形成領域の幅もしくはそれ以上の幅であることを特徴とする請求項１〜４のいずれかに記載の潤滑性付与部材装置。The lubricity imparting member device according to any one of claims 1 to 4 , wherein an action region of the lubricity imparting member is a width of a maximum image forming region in the longitudinal direction of the photosensitive member or a width larger than that. 請求項１〜５のいずれかに記載の潤滑性付与部材装置が単独のユニットで、もしくは他のプロセス装置との組み合わせで、或いはプロセスカートリッジ内に組み込まれ、感光体又は塗布部材と接触配置され、かつ感光体と上質紙の間の静止摩擦係数が０．１〜０．４に設定されて画像形成を行うことを特徴とする画像形成装置。The lubricity-imparting member device according to any one of claims 1 to 5 is a single unit, or a combination with another process device, or is incorporated in a process cartridge, and is placed in contact with a photoreceptor or an application member. An image forming apparatus characterized in that image formation is performed with a coefficient of static friction between the photosensitive member and fine paper set to 0.1 to 0.4. 塗布部材が接触帯電装置の帯電部材を兼ねることを特徴とする請求項６に記載の画像形成装置。The image forming apparatus according to claim 6 , wherein the coating member also serves as a charging member of the contact charging device. プロセスカートリッジが感光体、帯電装置及びクリーニング装置、もしくは感光体及び帯電装置から構成され、請求項１〜５のいずれかに記載の潤滑性付与部材装置を該感光体もしくは該帯電部材のいずれかと接触作用する様に配置して画像形成を行うことを特徴とする請求項６又は７に記載の画像形成装置。Process cartridge photoreceptor, a charging device and a cleaning device, or is composed of the photosensitive member and the charging device, in contact with either the lubricity providing member device photoconductor or the charging member according to any one of claims 1 to 5 the image forming apparatus according to claim 6 or 7, characterized in that the placed image formation so as to act.
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