JP2004093865A - Electrophotographic apparatus, electrophotographic photoreceptor, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic apparatus whose photoreceptor has a small scraped quantity and is less fused or flawed. <P>SOLUTION: In the electrophotographic apparatus which has the photoreceptor, an electrostatic charging means, an information writing means, a developing means, a transfer means, a developer electrostatic charging quantity control means, and a residual developer image uniformizing means and applies an AC voltage with a superposed DC high voltage to the developer image uniformizing means and a DC voltage with a specified polarity to the developer electrostatic charging quantity control means, the photoreceptor has at least one or more constitution units of a polyarylate resin shown by formulas (1) and (2) . In the formulas, X is -CR<SP>5</SP>R<SP>6</SP>-, a single bond, -O-, -S-, etc., and each of R1 to R10 is a hydrogen atom, a halogen atom, an alkyl group or an aryl group, etc. <P>COPYRIGHT: (C)2004,JPO

Description

【００１７】
式中、Ｘは−ＣＲ^５Ｒ^６−（ただしＲ^５及びＲ^６は各々独立に水素原子、トリフルオロメチル基、炭素数１〜６のアルキル基又は炭素数６〜１２のアリール基である）、置換されてもよい炭素数５〜１１の１，１−シクロアルキレン基、炭素数２〜１０のα，ω−アルキレン基、単結合、−Ｏ−、−Ｓ−、−ＳＯ−又は−ＳＯ_２−である。また、Ｒ^１〜Ｒ^４は水素原子、ハロゲン原子、炭素数１〜３のアルキル基又はアリール基である。ただし、少なくともＲ^１とＲ^２の一つ、かつ少なくともＲ^３とＲ^４の一つは水素原子以外とする。
【００１８】
【化７】

【００１９】
式中、Ｒ^７〜Ｒ^１０は水素原子、炭素数１〜３のアルキル基又はアリール基である。ただし、少なくともＲ^７とＲ^８の一つ、かつ少なくともＲ^９とＲ^１０の一つは水素原子以外とする。
【００２０】
また式中、アルキル基としてはメチル基、エチル基及びプロピル基等が挙げられる。アリール基としてはフェニル基及びナフチル基等が挙げられる。１，１−シクロアルキレン基としては１，１−シクロヘキシレン基及び１，１−シクロヘプチレン基等が挙げられる。α，ω−アルキレン基としては１，２−エチレン基、１，３−プロピレン基及び１，４−ブチレン基等が挙げられる。ハロゲン原子としてはフッ素原子、塩素原子及び臭素原子等が挙げられる。
【００２１】
これらの基が有してもよい置換基としては、フッ素原子、塩素原子及び臭素原子等のハロゲン原子、メチル基、エチル基及びプロピル基等のアルキル基、フェニル基、ナフチル基及びアンスリル基等のアリール基、ベンジル基及びフェネチル基等のアラルキル基及びメトキシ基、エトキシ基及びプロポキシ基等のアルコキシ基等が挙げられる。
【００２２】
本発明において、上記電子写真装置に用いられる電子写真感光体及びプロセスカートリッジが提供される。
【００２３】
【発明の実施の形態】
次に、このクリーナーレス方式の電子写真装置について、図１を用いて説明する。本例においては、帯電ローラーにマイナスのＤＣ電圧とＡＣ電圧を同時に印加し感光ドラムをマイナスに帯電し、レーザー光により静電潜像を書き込み、マイナスに帯電した現像剤を現像装置により感光ドラム上の露光部に現像する、反転現像方式の例を示した。
【００２４】
図１において、まず感光ドラム１は矢印の方向に回転し、帯電装置（帯電ローラー）２により帯電処理される。その後、露光光３により画像情報が静電潜像として書き込まれ、現像装置４によりトナー像として顕像化される。顕像化された感光ドラム上のトナー像は、転写装置（中間転写ベルト）９により転写材（不図示）に転写され、その後転写材は不図示の定着装置へと搬送される。転写行程後、電子写真感光体１上に残った残留トナーは、直流高圧が重畳された交流高圧が印加されている残留現像剤像を均一化する残留現像剤像均一化手段７によって均一化され、次に直流電圧を印加した現像剤帯電量制御手段６を通過し、上記帯電ローラーによる帯電行程において交流による除電が行われる。そして露光行程を通過した後、現像装置により現像容器内に回収され、再び現像処理に用いられる。以後上記の行程が繰り返される。
【００２５】
図１に記載されている現像剤帯電量制御手段６、残留現像剤像均一化手段７は固定のブラシ状部材を用いたが、ブラシ回転体、弾性ローラー体、シート状部材等の任意の形態の部材にすることができる。また、この部材は電子写真感光体に対してその長手方向にスラストさせ、電位付与性をより均一にさせることもできる。
【００２６】
次に、電子写真感光体の構成について説明する。
【００２７】
電子写真感光体は、感光層が電荷輸送材料と電荷発生材料とを同一の層に含有する単層型、電荷輸送材料を含有する電荷輸送層と電荷発生材料を含有する電荷発生層とを有する積層型のいずれの場合にも適用されるが、電子写真特性的には積層型が好ましい。
【００２８】
感光層を形成するためのバインダー樹脂及び溶媒は、用いる感光層における限定はなく、バインダー樹脂に電子写真感光体を形成させるための材料（例えば、電荷発生材や電荷輸送材）を溶解及び分散させて用いる層、例えば、積層型電子写真感光体においては、電荷発生層、電荷輸送層、保護層に可能であり、単層型においても可能である。
【００２９】
電荷発生材としては、通常知られているものが使用可能であり、例えば、セレン−テルル、ピリリウム、金属フタロシアニン、無金属フタロシアニン、アントアントロン、ジベンズピレンキノン、トリスアゾ、シアニン、ジスアゾ、モノアゾ、インジゴ及びキナクドリン等の各顔料が挙げられる。これらの顔料は、０．３〜４倍の質量のバインダー樹脂及び溶剤と共に、ホモジナイザー、超音波分散、ボールミル、振動ミル、サンドミルアトライター、ロールミル又は液衝突型高速分散機等を使用して、十分に分散した分散液とする。積層型電子写真感光体の場合、この液を塗布し、乾燥することによって電荷発生層が得られる。膜厚は５μｍ以下であることが好ましく、特には０．１〜２μｍであることが好ましい。
【００３０】
電荷輸送材は、通常用いられるものが使用でき、例えば、トリアリールアミン系化合物、ヒドラゾン系化合物、スチルベン系化合物、ピラゾリン系化合物、オキサゾール系化合物、トリアリルメタン系化合物及びチアゾール系化合物等が挙げられる。これらの化合物は、バインダー樹脂と共に溶剤に溶解し溶液とする。
積層型電子写真感光体の場合、この液を塗布し、乾燥することによって電荷輸送層が得られる。膜厚は５〜４０μｍであることが好ましく、特には１５〜３０μｍであることが好ましい。
【００３１】
感光層が単層型の場合は、上述のような電荷発生材や電荷輸送材を上述のようなバインダー樹脂に分散し及び溶解した溶解した溶液を塗布し、乾燥することによって形成することができる。膜厚は５〜４０μｍであることが好ましく、特には１５〜３０μｍであることが好ましい。
【００３２】
次に、本発明のポリアリレート樹脂について説明する。
【００３３】
有機系電子写真感光体においては、有機光導電材料をバインダー樹脂に溶解又は分散して、塗膜を形成して用いるのが通常である。その塗膜は、有機光導電材料とバインダー樹脂を溶媒に溶解又は分散後、塗布乾燥して形成される。
【００３４】
バインダー樹脂としては、例えば、ポリメチルメタクリレート、ポリスチレン及びポリ塩化ビニル等のビニル重合体及びその共重合体、ポリカーボネート、ポリエステル、ポリアリレート、ポリスルフォン、フェノキシ樹脂、エポキシ樹脂又はシリコーン樹脂等の材料が用いられているのが一般的である。
【００３５】
しかしながら、これらのバインダー樹脂においては、溶解／製膜時のポリマー鎖の絡み合いが十分に発現されないことから、電子写真感光体の塗膜としての強度が十分に得られないことがあり、こういったことで複数の帯電工程を持つプロセスにおいてトナー融着、キズ、削れ量の増加に伴う寿命の短命化といった問題が生じていたと考えられる。つまり対策の方向としては電子写真感光体の表面層の強度を向上させることであり、本発明のポリアリレート樹脂は本発明の様な電子写真装置での使用に適していると考えられる。
【００３６】
以下に式（１）で示される構成単位の具体例を示すが、これらに限られるものではないが、本発明では特に（１−２）が好ましい。分子量としてＭｗ＝２００００〜２０００００が好ましく、強度や生産性等の面から、５００００〜１５００００が特に好ましい。
【００３７】
【化８】

【００３８】
【化９】

【００３９】
以下に式（２）で示される構成単位の具体例を示すが、これらに限られるものではないが、本発明では特に（２−４）が好ましい。また、分子量としてＭｗ＝２００００〜２０００００が好ましく、強度や生産性等の面から、５００００〜１５００００が特に好ましい。
【００４０】
【化１０】

【００４１】
また、式（１）で示される構成単位と、式（２）で示される構成単位との共重合体の場合、その具体例としては、上記した構成単位例（１−１）〜（１−１４）と構成単位例（２−１）〜（２−７）との組み合わせについては、限定されない。
【００４２】
しかし共重合の比率は、式（１）／式（２）＝９５／５〜５／９５において各々の特性の効果を出すことができるが、本発明の耐摩耗性の効果をより発現させるためには、８０／２０〜２０／８０とすることが好ましい。この場合も分子量としては、Ｍｗ＝２００００〜２０００００が好ましく、特に５００００〜１５００００が好ましい。
【００４３】
次に、電子写真感光体の表面層に用いられるシリコーン系粉末潤滑材としては、電子写真感光体の表面の滑り性を向上させ、電子写真特性を悪化させないものであればどのようなものを使ってもかまわないが、特には東亞合成化学工業（株）製の「商品名：アロンＧＳ−１０１ＣＰ」が好ましい。
【００４４】
本発明に用いられるシリコーン変性ポリカーボネートにおいて式（５）で示される構成単位を有する重合体と式（５）、（６）及び（７）で示される構成単位を有する共重合体の割合は、耐ソルベントクラック性、耐久性及び電気特性に対する環境安定性、溶液安定性に依存する製造安定性を考慮して制御しなければならないが、式（５）、（６）及び（７）で示される構成単位を有する共重合体が式（５）で示される構成単位を有する重合体に対して質量割合で０．１〜９５質量％の範囲であることが好ましく、０．５〜８０質量％の範囲が特に好ましい。
【００４５】
特に、式（５）及び（６）で示される構成単位の質量をαとし、式（７）で示される構成単位をβとしたときにβ／（α＋β）の値が０．０１〜０．１の範囲であるときは、前記重合体の割合は１〜１５質量％の範囲であることが好ましく、３〜１０質量％の範囲が特に好ましい。
【００４６】
また、式（５）及び（７）で示される構成単位の質量をγとし、式（６）で示される構成単位をδとしたときにδ／（γ＋δ）の値が０．３〜０．８の範囲であることが好ましく、０．４〜０．８の範囲が特に好ましい。
【００４７】
【化１１】

【００４８】
そして本発明において用いられるフッ素系樹脂粉体としては、主に電子写真感光体の表面の耐磨耗性を更に向上させるもので、４フッ化エチレン、３フッ化塩化エチレン樹脂、６フッ化エチレンプロピレン樹脂、フッ化ビニル樹脂、フッ化ビニリデン樹脂、２フッ化２塩化エチレン樹脂及びこれらの共重合体のなかから１種あるいは２種以上を適宜選択するのが好ましいが、特に、４フッ化エチレン樹脂及びフッ化ビニリデン樹脂が好ましい。樹脂粒子の分子量や粒子の粒径は適宜選択することができ、特に制限されるものではない。
【００４９】
図１及び図２は本発明に従う電子写真装置例の概略構成図である。
【００５０】
図２に示すフルカラーレーザープリンタは、転写方式電子写真プロセス利用、接触帯電方式、反転現像方式、最大通紙サイズがＡ３サイズのフルカラーレーザープリンタであり、複数個のプロセスカートリッジ８（Ｐ−ＣＲＧ）を有し、一旦第２の画像担持体である中間転写ベルト９に連続的に多重転写し、フルカラープリント画像を得る４連ドラム方式（インライン）プリンタである。
【００５１】
図２において無端状の中間転写ベルト９が、駆動ローラー９ｅ、テンションローラ９ｆ及び２次転写対向ローラー１０ａに懸架され、図中矢印の方向に回転している。
【００５２】
プロセスカートリッジ８は、上記中間転写ベルト９に直列にイエロー、マゼンタ、シアン、ブラックの順に４本配置されている。
【００５３】
以下、プロセスカートリッジ８について図１に基づいて説明する。
【００５４】
イエロートナーを現像するプロセスカートリッジ８において、１は像担持体としての回転ドラム型の電子写真感光体（感光ドラム）である。外形３０ｍｍ、長手長さは３７０ｍｍであり、中心支軸を中心に１００ｍｍ／ｓｅｃのプロセススピード（周速度）をもって矢印の方向に回転駆動されている。
【００５５】
帯電工程では、接触帯電器としての帯電ローラー２に所定の条件の電圧が印加されており、電子写真感光体ドラム１面上を一様に負極性に帯電処理を行う。この帯電ローラー２の長手長さは３２０ｍｍであり、芯金（支持部材）２ａの外回りに、下層２ｂと、中間層２ｃと、表面層２ｄを下から順次に積層した３層構成としている。下層２ｂは帯電音を低減するための発泡スポンジ層であり、中間層２ｃは帯電ローラー全体として均一な抵抗を得るための抵抗層であり、表層２ｄは感光ドラム１上にピンホール等の欠陥があってもリークが発生するのを防止するために設けている保護層である。本例の帯電ローラー２は、芯金２ａとして直径６ｍｍのステンレス丸棒を用い、表層としてフッ素樹脂にカーボンを分散させており、ローラーとしての外径は１４ｍｍ、ローラー抵抗は１０^４Ω〜１０^７Ωとしている。
【００５６】
この帯電ローラー２は、芯金２ａの両端部をそれぞれ軸受け部材により回転自在に保持させると共に押し圧ばねによって感光ドラム１方向に付勢して感光ドラム１の表面に対して所定の押圧力をもって圧接させており、感光ドラム１の回転に従動して回転する。そして電源２０から直流電圧に周波数ｆの交流電圧を重畳した所定の振動電圧（バイアス電圧Ｖｄｃ＋Ｖａｃ）が芯金２ａを介して帯電ローラー２に印加されることで、回転する感光ドラム１の周面が所定の電位に帯電処理される。
【００５７】
本実施例においては直流電圧；−５００Ｖ、交流電圧；周波数ｆ＝１１５０Ｈｚ、ピーク間電圧Ｖｐｐ＝１４００Ｖ、正弦波とを重畳した振動電圧であり、感光ドラム１の周面は−５００Ｖ（暗電位Ｖｄ）に一様に接触帯電処理される。
【００５８】
図２において、帯電ローラクリーニング部材２ｆは、可撓性を持つクリーニングフィルムである。このクリーニングフィルム２ｆは、帯電ローラー２の長手方向に対し平行に配置されかつ同長手方向に対し一定量の往復運動をする支持部材２ｇに一端を固定され、自由端側近傍の面において帯電ローラー２と接触ニップを形成するよう配置されている。支持部材２ｇが、プリンタの駆動モーターによりギア列を介して長手方向に対し一定量の往復運動駆動されて帯電ローラー表層２ｄがクリーニングフィルム２ｆで摺擦される。これにより帯電ローラー表層２ｄの付着汚染物（微粉トナーや外添剤等）の除去がなされる。
【００５９】
帯電ローラー２により所定の極性・電位に一様に帯電処理された後は、不図示の画像露光手段（カラー原稿画像の色分解・結像露光光学系、画像情報の時系列電気デジタル画素信号に対応して変調されたレーザビームを出力するレーザスキャンによる走査露光系等）による露光光３を受けることにより目的のカラー画像における第１の色成分像（イエロー成分像）に対応した静電潜像が形成される。本実施例では露光装置として半導体レーザーを用いたレーザビームスキャナを用い、不図示の画像読み取り装置等のホスト装置からプリンタ側に送られた画像信号に対応して変調されたレーザー光を出力して回転感光ドラム１の一様帯電処理面をレーザー走査露光（イメージ露光）する。このレーザー走査露光により感光ドラム１面のレーザー光で照射されたところの電位が低下することで回転感光ドラム１面には走査露光した画像情報に対応した静電潜像が形成されていく。本実施例においては、露光部電位を−１５０Ｖとしている。
【００６０】
次いで、その静電潜像が第１現像器４（イエロー現像器）により第１色であるイエロートナーにより現像される。
【００６１】
図２において、感光ドラム１上に形成されたイエロー画像は、中間転写ベルト９との１次転写ニップ部へ進入する。転写ニップ部では中間転写ベルト９の裏側に転写ローラー９ｇを当接させている。転写ローラー９ｇには各ポートで独立にバイアス印加可能とするため、１次転写バイアス源９ａ〜９ｄを有している。中間転写ベルト９は１色目のポートでまずイエローを転写し、次いで先述した同様の工程を経た、各色に対応する感光ドラム１より順次マゼンタ、シアン、ブラックの各色を各ポートで多重転写する。中間転写ベルト９上で形成された４色フルカラー画像は、次いで２次転写ローラー１０により、給紙ローラー１２から送られてきた転写材Ｐに一括転写され、不図示の定着装置によって溶融定着されカラープリント画像を得る。
【００６２】
中間転写ベルト９上に残留する２次転写残トナーは、中間転写ベルトクリーナ１１でブレードクリーニングされ、次作像工程に備える。
【００６３】
図１において、トナー帯電制御手段６と残留トナー像均一化手段７が感光ドラム１に当接されている。両者とも本実施例では導電性の繊維からなるブラシ部材を用いている。具体的には、トナー帯電制御手段６は横長の電極板６２にブラシ部６１を具備させたものであり、また残留トナー均一化手段７についても同様に電極板７２にブラシ部７１を具備させてなる。そして、ブラシ部６１及び７１を感光ドラム１面に当接させて固定支持させて配設している。ブラシ部６１及び７１は、レーヨン、アクリル及びポリエステル等の繊維にカーボンや金属粉を含ませて抵抗値を制御したものである。ブラシ部６１及び７１は、感光ドラム表面及び転写残トナーに均一に接触できるように、太さとしては３０デニール以下、密度としては１〜５０万本／ｉｎｃｈ^２以上が好ましい。本実施例では、ブラシ部６１、７１共に６デニール、１０万本／ｉｎｃｈ^２、毛足の長さ５ｍｍで、ブラシの抵抗は６×１０^３Ω・ｃｍとした。これらのトナー帯電制御手段６と残留トナー像均一化手段７を、ブラシ部６１及び７１が感光ドラム１面に対して侵入量１ｍｍとなるように当接させ、感光ドラム１との当接ニップ部幅は５ｍｍとした。
【００６４】
本実施例において、トナー帯電制御手段６には、負極性の電圧が電源２１より印加されている。また、転写残トナー像均一化手段７には、直流電圧が重畳された交流電圧が電源２２より印加されている。
【００６５】
トナー帯電制御手段６には−７００Ｖの直流バイアスを印加、転写残トナー像均一化手段７に印加したバイアスは、正弦波であり、Ｖｐｐ＝４００Ｖ、周波数＝１１５０Ｈｚ、Ｖｄｃ＝＋２５０Ｖとした。
【００６６】
【実施例】
（実施例１）
本発明の電子写真感光体はアルミニウムシリンダーを支持体とし、それに、以下の材料より構成される塗料を支持体上に浸漬法で塗布し、１４０℃で３０分間熱硬化して１５μｍの導電層を形成した。
【００６７】
導電性顔料：ＳｎＯ_２コート処理硫酸バリウム　　　　　　　　１０部
抵抗調節用顔料：酸化チタン　　　　　　　　　　　　　　　　　２部
バインダー樹脂：フェノール樹脂　　　　　　　　　　　　　　　６部
レベリング材：シリコーンオイル　　　　　　　　　　　０．００１部
溶剤：メタノール／メトキシプロパノール＝０．２／０．８　　２０部
【００６８】
次に、この上にＮ−メトキシメチル化ナイロン４．５部及び共重合ナイロン１．５部をメタノール６５部／ｎ−ブタノール３０部の混合溶媒に溶解した溶液を浸漬法で塗布し、膜厚が０．６μｍの中間層を形成した。
【００６９】
次に、ＣｕＫαの特性Ｘ線回折におけるブラッグ角（２θ±０．２°）の７．４°及び２８．２°に強いピークを有するヒドロキシガリウムフタロシアニン結晶３．５部とポリビニルブチラール樹脂（商品名：エスレックＢＨ−Ｓ、積水化学工業社製）１部をシクロヘキサノン１２０部に添加し、１ｍｍφガラスビーズを用いたサンドミルで３時間分散し、これにメチルエチルケトン１２０部を加えて希釈して電荷発生層用塗料を調製した。下引き層上に、この電荷発生層用塗料を浸漬塗布し、１００℃で１０分間乾燥して、膜厚が０．１５μｍの電荷発生層を形成した。
【００７０】
次に、下記式で示されるアミン化合物９部、
【００７１】
【化１２】

下記式で示されるアミン化合物１部、
【００７２】
【化１３】

バインダー樹脂として構成単位例（１−２）で示される化合物（Ｍｗ＝７５０００）１０部をモノクロロベンゼン５０部／ジクロロメタン５０部の混合溶剤に溶解し、電荷輸送層用の塗布液を得た。塗布液を浸漬塗布法で塗布し、１２０℃にて１時間乾燥し、膜厚が２７μｍの電荷輸送層を形成した。
【００７３】
このようにして作製した電子写真感光体を図２に示されるフルカラー電子写真装置に装着し、上述の帯電設定において、２３℃／６０％、１５℃／１０％、３０℃／８０％の各環境下でフルカラー画像２万枚の連続耐久試験を行った。
【００７４】
評価は電子写真感光体のトナー融着、キズの有無、削れ量、そして画像特性の４項目に着眼して行ない、結果は表１に示す。
【００７５】
なお各評価項目の評価基準は次の通りである。
【００７６】
（ａ）電子写真感光体のトナー融着
目視による４段階評価をした。評価基準は
Ａ：トナー融着無し、
Ｂ：耐久後半で軽微に発生、
Ｃ：耐久後半で発生、
Ｄ：耐久前半から発生
【００７７】
（ｂ）電子写真感光体のキズの有無
目視による４段階評価をした。評価基準は
Ａ：キズ無し、
Ｂ：耐久後半で軽微に発生、
Ｃ：耐久後半で発生、
Ｄ：耐久前半から発生
【００７８】
（ｃ）電子写真感光体の削れ量
１万枚あたりの４本の電子写真感光体の表面層の平均削れ量を（米）フィッシャー社製「パーマスコープＥ１１１型」による膜厚測定で調べた。
【００７９】
（ｄ）画像特性
目視による４段階評価。評価基準はオリジナル原稿を基準にして、ベタ黒画像の均一性、階調性、細線再現性について目視で総合的に４段階に評価した。
【００８０】
Ａ：優、Ｂ：良、Ｃ：普通、Ｄ：不良
【００８１】
（実施例２）
電荷輸送層用のバインダー樹脂として構成単位例（１−４）（Ｍｗ＝７８０００）とした以外は、実施例１と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表１に示す。
【００８２】
（実施例３）
電荷輸送層用のバインダー樹脂として構成単位例（１−６）（Ｍｗ＝７００００）とした以外は、実施例１と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表１に示す。
【００８３】
（実施例４）
電荷輸送層用のバインダー樹脂として構成単位例（１−２）／（２−４）＝３０／７０からなる共重合体（Ｍｗ＝８００００）とした以外は、実施例１と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表１に示す。
【００８４】
（実施例５）
電荷輸送層用のバインダー樹脂として構成単位例（１−２）／（２−４）＝５０／５０からなる共重合体（Ｍｗ＝７８０００）とした以外は、実施例１と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表１に示す。
【００８５】
（実施例６）
電荷輸送層用のバインダー樹脂として構成単位例（１−２）／（２−４）＝７０／３０からなる共重合体（Ｍｗ＝７５０００）とした以外は、実施例１と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表１に示す。
【００８６】
（実施例７〜１２）
実施例１〜６の電子写真感光体において電荷輸送層にクシ型シリコーン系グラフトポリマー（商品名：アロンＧＳ−１０１ＣＰ、東亞合成化学工業（株）製）を０．２部添加した以外は、実施例１〜６と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表１に示す。
【００８７】
（実施例１３〜１８）
実施例１〜６の電子写真感光体において電荷輸送層に４フッ化エチレン樹脂（商品名：ルブロンＬ２、ダイキン工業（株）製）を１部分散させた以外は、実施例１〜６と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表２に示す。
【００８８】
（実施例１９〜２４）
実施例７〜１２の電子写真感光体においてアリレート樹脂を９．５部、式（５）、（６）及び（７）で示されるシリコーン変性ポリカーボネート樹脂｛式（５）が共重合体の全質量の４５質量％であり、式（６）が４５質量％である共重合体（粘度平均分子量２．２１×１０^４）｝を０．５部とした以外は、実施例７〜１２と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表２に示す。
【００８９】
（比較例１）
実施例１における電荷輸送層用のバインダー樹脂としてポリカーボネート樹脂（商品名：ユーピロンＺ−４００、三菱ガス化学（株）製）に代えた以外は、実施例１と同様にして電子写真感光体を作製し、同様な評価を行った。結果は表２に示す。
【００９０】
（比較例２）
実施例１における電荷輸送層用のバインダー樹脂としてポリカーボネート樹脂（テイジンパンライトＬ−１２５０、帝人化成（株）製）に代えた以外は、実施例１と同様にして電子写真感光体を作製し、実施例１と同様な評価を行った。結果は表２に示す。
【００９１】
（比較例３）
実施例１において、残留現像剤像均一化手段に直流高圧のみを印加した以外は、実施例１と同様な評価を行った。
【００９２】
結果はドラム削れ、キズの発生は無かったが、出力画像が回収されない転写残トナーの影響で正規の出力画像が得られなかった。そのためか融着が発生した。結果は表２に示す。
【００９３】
【表１】

【００９４】
【表２】

【００９５】
【発明の効果】
以上のように、本発明によって、残留現像剤像均一化手段に直流高圧が重畳された交流高圧を印加、前記現像剤帯電量制御手段に前記所定の極性の直流電圧を印加する電子写真装置において、該電子写真装置に用いられる電子写真感光体が特定のポリアリレート樹脂の構成単位を含有することで融着、キズ、削れといった問題が解決できる。
【図面の簡単な説明】
【図１】本発明の電子写真装置の概略断面図である。
【図２】本発明のフルカラー電子写真装置の概略断面図である。
【符号の説明】
１　電子写真感光体
２　帯電装置
３　露光光
４　現像装置
５　Ｔ−ＣＲＧ
６　現像剤帯電量制御手段
７　転写残現像剤像均一化手段
８　プロセスカートリッジ
９　中間転写ベルト
１０　２次転写ローラー
１１　中間転写ベルトクリーナ
１２　給紙ローラー
２０、２１、２２　電源[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic apparatus such as a copying machine, a printer, and a facsimile having an electrophotographic image forming process, an electrophotographic photoreceptor used in these apparatuses, and a process cartridge detachable from these apparatuses.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a transfer type image forming apparatus such as a copying machine, a printer, a facsimile or the like using a transfer type electrophotographic method is an electrophotographic photosensitive member which is a rotating drum type image carrier in general, and an electrophotographic photosensitive member thereof. A charging device (charging step) for uniformly charging to a predetermined polarity / potential; an exposure device (exposure step) as information writing means for forming an electrostatic latent image on the charged electrophotographic photosensitive member; A developing device (developing process) for visualizing the electrostatic latent image formed on the body with toner as a developer, and a transferring device (transfer process) for transferring the toner image from the electrophotographic photosensitive member surface to a transfer material such as paper. ), A cleaning device (cleaning process) for removing the toner slightly remaining on the electrophotographic photosensitive member after the transfer process to clean the electrophotographic photosensitive member surface, and a fixing device for fixing the toner image on the transfer material ( Chakukotei), etc. are composed of, the electrophotographic photosensitive member is repeatedly an electrophotographic process (charging, exposure, development, transfer and cleaning) is applied is used for image formation.
[0003]
A waste toner collecting container that stores toner remaining on the electrophotographic photosensitive member removed from the electrophotographic photosensitive member surface by the cleaning device is provided in the cleaning device. Therefore, in order to obtain a device having a long durability life, it is necessary to increase the size of the container, which is disadvantageous in terms of miniaturization of the device.
[0004]
Therefore, the cleaning device having the waste toner collecting container is discarded, and the transfer residual toner on the electrophotographic photosensitive member after the transfer process is removed and collected from the electrophotographic photosensitive member by "simultaneous development" in the developing device and reused. There is a cleanerless electrophotographic apparatus.
[0005]
Simultaneous development and cleaning involves transferring the untransferred toner on the electrophotographic photosensitive member after transfer during the subsequent developing step, that is, charging the electrophotographic photosensitive member and exposing it to form an electrostatic latent image. Due to the fogging bias (fogging potential difference Vback, which is a potential difference between the DC voltage applied to the developing device and the surface potential of the electrophotographic photosensitive member) during the latent image developing process, the surface of the electrophotographic photosensitive member that should not be developed with toner In this method, the transfer residual toner existing on the portion (non-image portion) is collected in a developing device. According to this method, since the transfer residual toner is collected in the developing device and reused for the development of the electrostatic latent image in the next and subsequent steps, waste toner is eliminated, and maintenance work is reduced. And the absence of a waste toner container is advantageous in reducing the size of the electrophotographic apparatus.
[0006]
On the other hand, in recent years, a corona charger has been used as a charging means, and a roller charging method using a conductive roller as a contact charging member has been particularly preferably used in terms of charging stability. In the roller charging, a conductive elastic roller (charging roller) is brought into pressure contact with a member to be charged, and a voltage is applied to the member to charge the member.
[0007]
Regarding this charging method, as disclosed in JP-A-63-149669, an AC component having a peak-to-peak voltage of 2 × Vth or more is superimposed on a DC voltage corresponding to a desired surface potential Vd of a member to be charged. An AC charging system in which a voltage is applied to a contact charging member has been proposed and is being put to practical use. Due to the potential leveling effect of the AC, the charging can be made more uniform than in the DC charging method, and the potential of the member to be charged substantially converges to Vd, which is the center of the peak of the AC voltage.
[0008]
In a cleanerless electrophotographic apparatus for removing and recovering transfer residual toner on the electrophotographic photosensitive member after the transfer process by simultaneous development and cleaning in a developing device, the above-described contact charging device was used as a charging device for the electrophotographic photosensitive member. In this case, when the transfer residual toner on the electrophotographic photosensitive member passes through the charging portion, which is the contact nip portion of the electrophotographic photosensitive member and the contact charging device, particularly the charge polarity of the transfer residual toner is opposite to the normal polarity. The toner inverted in polarity adheres to the contact charging device, causing the contact charging device to be more unacceptably contaminated with toner and causing poor charging.
[0009]
This is due to the fact that the toner as the developer contains a small amount of toner whose charge polarity is originally reversed to the opposite polarity from the normal polarity, or that the charge polarity is the normal polarity. This is because, even with toner, there is a toner whose charge polarity is inverted due to an influence of a transfer bias or a peeling discharge, or a toner whose charge amount is reduced due to charge removal.
[0010]
In other words, the transfer residual toner includes a toner having a normal charge polarity, a reverse toner having a reverse polarity, and a toner having a small charge amount, and the reverse toner or the toner having a small charge amount contacts the electrophotographic photosensitive member. It easily adheres to the contact charging device when passing through the charging portion, which is the contact nip portion of the charging device.
[0011]
Further, in order to remove and collect the transfer residual toner on the electrophotographic photosensitive member by simultaneous cleaning of the developing device with the developing device, the transfer residual toner on the electrophotographic photosensitive member carried through the charging section and carried to the developing section is removed. It is necessary that the charging polarity is a regular polarity and that the charging amount is a charging amount of the toner that can develop the electrostatic latent image on the electrophotographic photosensitive member by the developing device. Inverted toner and toner with an inappropriate charge amount cannot be removed / recovered from the electrophotographic photosensitive member to the developing device, which causes a defective image.
[0012]
Japanese Patent Application Laid-Open No. 2001-215798 discloses an electrophotographic apparatus in which a transfer residual toner equalizing unit is provided downstream of a transfer unit, and a toner charge amount control unit is provided further downstream and upstream of a charging unit for charging an electrophotographic photosensitive member. There has been proposed an electrophotographic apparatus characterized by applying an AC high voltage on which a DC high voltage is superimposed to a transfer residual toner uniforming means (residual developer image uniforming means) in order to further improve image defects. I have.
[0013]
[Problems to be solved by the invention]
However, applying an alternating high voltage to the transfer residual developer image uniformizing means increases the damage to the electrophotographic photosensitive member due to charging, and thus tends to cause problems such as scraping, flaws, and fusion. As a result, a problem such as shortening the life of the electrophotographic photosensitive member is caused.
[0014]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic apparatus in which an alternating high voltage in which a direct current high voltage is superimposed is applied to a residual developer image uniforming means, and a predetermined direct current voltage is applied to a developer charge amount controlling means. An object of the present invention is to provide an electrophotographic apparatus which has a small amount of scraping and does not cause fusion or flaws, an electrophotographic photosensitive member and a process cartridge used in the electrophotographic apparatus.
[0015]
[Means for solving the problem]
According to the present invention, an electrophotographic photoreceptor, charging means for charging a surface of the electrophotographic photoreceptor, information writing means for forming an electrostatic latent image on the charged electrophotographic photoreceptor, and a predetermined polarity for the electrostatic latent image Developing means for supplying the developer and visualizing the electrostatic latent image, transfer means for transferring the visualized developer image to a transfer material, and a developer located on the upstream side of the charging means and on the electrophotographic photosensitive member surface. A developer charge amount control unit that is charged, and a residue that is located upstream of the developer charge amount control unit and downstream of the transfer unit and remains on the electrophotographic photoreceptor surface after transferring the developer image to a transfer material. A residual developer image equalizing means for equalizing the developer image, applying an AC high voltage on which a DC high voltage is superimposed to the residual developer image uniformizing means, and applying the predetermined voltage to the developer charge amount control means. In an electrophotographic apparatus for applying a polar DC voltage, The electrophotographic photosensitive member is represented by the following formula (1), an electrophotographic apparatus characterized in that it contains at least one structural unit of the polyarylate resin represented by (2).
[0016]
Embedded image

[0017]
Where X is -CR ⁵ R ⁶ -(R ⁵ And R ⁶ Each independently represents a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms), an optionally substituted 1,1-cycloalkylene having 5 to 11 carbon atoms Group, α, ω-alkylene group having 2 to 10 carbon atoms, single bond, —O—, —S—, —SO— or —SO ₂ -. Also, R ¹ ~ R ⁴ Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms or an aryl group. However, at least R ¹ And R ² One and at least R ³ And R ⁴ Is one other than a hydrogen atom.
[0018]
Embedded image

[0019]
Where R ⁷ ~ R ¹⁰ Is a hydrogen atom, an alkyl group or an aryl group having 1 to 3 carbon atoms. However, at least R ⁷ And R ⁸ One and at least R ⁹ And R ¹⁰ Is one other than a hydrogen atom.
[0020]
In the formula, examples of the alkyl group include a methyl group, an ethyl group, and a propyl group. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the 1,1-cycloalkylene group include a 1,1-cyclohexylene group and a 1,1-cycloheptylene group. Examples of the α, ω-alkylene group include a 1,2-ethylene group, a 1,3-propylene group, and a 1,4-butylene group. Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.
[0021]
Examples of the substituent which these groups may have include a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, an alkyl group such as a methyl group, an ethyl group and a propyl group, a phenyl group, a naphthyl group and an anthryl group. Examples include aralkyl groups such as aryl group, benzyl group and phenethyl group, and alkoxy groups such as methoxy group, ethoxy group and propoxy group.
[0022]
In the present invention, an electrophotographic photosensitive member and a process cartridge used in the above electrophotographic apparatus are provided.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the cleanerless electrophotographic apparatus will be described with reference to FIG. In this example, a negative DC voltage and an AC voltage are simultaneously applied to the charging roller to negatively charge the photosensitive drum, write an electrostatic latent image with laser light, and apply a negatively charged developer onto the photosensitive drum by a developing device. The example of the reversal development method in which development is performed on the exposed portion is shown.
[0024]
In FIG. 1, the photosensitive drum 1 first rotates in the direction of the arrow, and is charged by a charging device (charging roller) 2. Thereafter, image information is written as an electrostatic latent image by the exposure light 3, and is visualized as a toner image by the developing device 4. The visualized toner image on the photosensitive drum is transferred to a transfer material (not shown) by a transfer device (intermediate transfer belt) 9, and then the transfer material is conveyed to a fixing device (not shown). After the transfer process, the residual toner remaining on the electrophotographic photoreceptor 1 is made uniform by the residual developer image equalizing means 7 for equalizing the residual developer image to which the AC high voltage on which the DC high voltage is superimposed is applied. Then, the charge passes through the developer charge amount control means 6 to which a DC voltage is applied, and the charge is removed by AC in the charging process by the charging roller. Then, after passing through the exposure process, the toner is collected in a developing container by a developing device and used again for the developing process. Thereafter, the above steps are repeated.
[0025]
The developer charge amount control means 6 and the residual developer image uniforming means 7 shown in FIG. 1 use a fixed brush-like member. However, any form such as a brush rotating body, an elastic roller body, and a sheet-like member is used. Member. In addition, this member can thrust the electrophotographic photosensitive member in the longitudinal direction to make the potential applying property more uniform.
[0026]
Next, the configuration of the electrophotographic photosensitive member will be described.
[0027]
The electrophotographic photoreceptor has a single layer in which a photosensitive layer contains a charge transport material and a charge generation material in the same layer, a charge transport layer containing a charge transport material, and a charge generation layer containing a charge generation material. Although the present invention is applied to any of the laminated types, the laminated type is preferable in terms of electrophotographic characteristics.
[0028]
The binder resin and the solvent for forming the photosensitive layer are not limited in the photosensitive layer to be used, and dissolve and disperse a material (for example, a charge generating material or a charge transporting material) for forming the electrophotographic photosensitive member in the binder resin. For example, in the case of a layer type electrophotographic photoreceptor, it can be used as a charge generation layer, a charge transport layer, and a protective layer, and can be a single layer type.
[0029]
As the charge generating material, those generally known can be used, for example, selenium-tellurium, pyrylium, metal phthalocyanine, metal-free phthalocyanine, anthantrone, dibenzpyrene quinone, trisazo, cyanine, disazo, monoazo, indigo And each pigment such as quinacudrine. These pigments can be sufficiently mixed with a binder resin and a solvent having a mass of 0.3 to 4 times by using a homogenizer, an ultrasonic dispersion, a ball mill, a vibration mill, a sand mill attritor, a roll mill or a liquid collision type high-speed disperser. To a dispersion. In the case of a laminated electrophotographic photoreceptor, a charge generation layer is obtained by applying and drying this liquid. The thickness is preferably 5 μm or less, particularly preferably 0.1 to 2 μm.
[0030]
As the charge transport material, those commonly used can be used, and examples thereof include a triarylamine compound, a hydrazone compound, a stilbene compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound. . These compounds are dissolved in a solvent together with a binder resin to form a solution.
In the case of a laminated electrophotographic photoreceptor, a charge transport layer is obtained by applying and drying this solution. The film thickness is preferably from 5 to 40 μm, and particularly preferably from 15 to 30 μm.
[0031]
When the photosensitive layer is a single-layer type, the photosensitive layer can be formed by applying a solution in which the charge generation material or the charge transport material is dispersed and dissolved in the binder resin as described above, and dried. . The film thickness is preferably from 5 to 40 μm, and particularly preferably from 15 to 30 μm.
[0032]
Next, the polyarylate resin of the present invention will be described.
[0033]
In an organic electrophotographic photoreceptor, an organic photoconductive material is usually dissolved or dispersed in a binder resin to form a coating film and used. The coating film is formed by dissolving or dispersing the organic photoconductive material and the binder resin in a solvent, and then coating and drying.
[0034]
As the binder resin, for example, materials such as polymethyl methacrylate, vinyl polymers such as polystyrene and polyvinyl chloride and copolymers thereof, polycarbonate, polyester, polyarylate, polysulfone, phenoxy resin, epoxy resin or silicone resin are used. It is common that it is.
[0035]
However, in these binder resins, since the entanglement of the polymer chains at the time of dissolution / film formation is not sufficiently exhibited, the strength as a coating film of the electrophotographic photosensitive member may not be sufficiently obtained. Thus, it is considered that a problem such as shortening of the life due to an increase in the amount of toner fusion, flaws and abrasion has occurred in a process having a plurality of charging steps. That is, the direction of the countermeasure is to improve the strength of the surface layer of the electrophotographic photosensitive member, and it is considered that the polyarylate resin of the present invention is suitable for use in an electrophotographic apparatus as in the present invention.
[0036]
Specific examples of the structural unit represented by the formula (1) are shown below, but the present invention is not limited thereto, but (1-2) is particularly preferable in the present invention. The molecular weight is preferably Mw = 20,000 to 200,000, and particularly preferably 50,000 to 150,000 in view of strength, productivity and the like.
[0037]
Embedded image

[0038]
Embedded image

[0039]
Specific examples of the structural unit represented by the formula (2) are shown below, but the present invention is not limited thereto, but (2-4) is particularly preferable in the present invention. Further, the molecular weight is preferably Mw = 20,000 to 200,000, and particularly preferably 50,000 to 150,000 in view of strength, productivity and the like.
[0040]
Embedded image

[0041]
In the case of a copolymer of the structural unit represented by the formula (1) and the structural unit represented by the formula (2), specific examples thereof include the above-described structural unit examples (1-1) to (1-). There is no limitation on the combination of 14) and the structural unit examples (2-1) to (2-7).
[0042]
However, the effect of each characteristic can be obtained when the copolymerization ratio is expressed by the formula (1) / formula (2) = 95/5 to 5/95, but in order to further exhibit the effect of abrasion resistance of the present invention. Is preferably 80/20 to 20/80. Also in this case, the molecular weight is preferably Mw = 20,000 to 200,000, particularly preferably 50,000 to 150,000.
[0043]
Next, as the silicone-based powder lubricant used for the surface layer of the electrophotographic photosensitive member, any material can be used as long as it improves the slipperiness of the surface of the electrophotographic photosensitive member and does not deteriorate the electrophotographic characteristics. Although it does not matter, "Aron GS-101CP" manufactured by Toagosei Chemical Industry Co., Ltd. is particularly preferable.
[0044]
In the silicone-modified polycarbonate used in the present invention, the ratio of the polymer having the structural unit represented by the formula (5) to the copolymer having the structural unit represented by the formulas (5), (6) and (7) is as follows. It must be controlled in consideration of the solvent cracking property, the environmental stability with respect to durability and electrical properties, and the production stability depending on the solution stability, but the structure represented by the formulas (5), (6) and (7) Preferably, the copolymer having units has a mass ratio of 0.1 to 95% by mass, and more preferably 0.5 to 80% by mass, based on the polymer having the structural unit represented by the formula (5). Is particularly preferred.
[0045]
In particular, when the mass of the structural unit represented by the formulas (5) and (6) is α, and the structural unit represented by the formula (7) is β, the value of β / (α + β) is 0.01 to 0.1. When it is in the range of 1, the proportion of the polymer is preferably in the range of 1 to 15% by mass, and particularly preferably in the range of 3 to 10% by mass.
[0046]
When the mass of the structural unit represented by the formulas (5) and (7) is represented by γ, and the structural unit represented by the formula (6) is represented by δ, the value of δ / (γ + δ) is 0.3 to 0.5. 8 is preferable, and the range of 0.4 to 0.8 is particularly preferable.
[0047]
Embedded image

[0048]
The fluororesin powder used in the present invention mainly improves the abrasion resistance of the surface of the electrophotographic photoreceptor, and includes tetrafluoroethylene, trifluorinated ethylene resin, and hexafluoroethylene resin. It is preferable to appropriately select one or more of propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorinated ethylene chloride resin and copolymers thereof. Resins and vinylidene fluoride resins are preferred. The molecular weight of the resin particles and the particle size of the particles can be appropriately selected and are not particularly limited.
[0049]
1 and 2 are schematic structural views of an example of an electrophotographic apparatus according to the present invention.
[0050]
The full-color laser printer shown in FIG. 2 is a full-color laser printer using a transfer type electrophotographic process, a contact charging type, a reversal developing type, and a maximum paper passing size of A3 size, and includes a plurality of process cartridges 8 (P-CRG). This is a four-drum type (in-line) printer that has a multi-transfer and continuously obtains a full-color print image by temporarily performing multiple transfer to an intermediate transfer belt 9 serving as a second image carrier.
[0051]
In FIG. 2, an endless intermediate transfer belt 9 is suspended by a driving roller 9e, a tension roller 9f, and a secondary transfer opposing roller 10a, and rotates in the direction of the arrow in the figure.
[0052]
The four process cartridges 8 are arranged in series with the intermediate transfer belt 9 in the order of yellow, magenta, cyan, and black.
[0053]
Hereinafter, the process cartridge 8 will be described with reference to FIG.
[0054]
In the process cartridge 8 for developing yellow toner, reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (photosensitive drum) as an image carrier. It has an outer shape of 30 mm and a longitudinal length of 370 mm, and is rotationally driven in the direction of the arrow with a process speed (peripheral speed) of 100 mm / sec around the central support shaft.
[0055]
In the charging step, a voltage under a predetermined condition is applied to the charging roller 2 as a contact charger, and the surface of the electrophotographic photosensitive drum 1 is uniformly charged to a negative polarity. The charging roller 2 has a longitudinal length of 320 mm, and has a three-layer structure in which a lower layer 2b, an intermediate layer 2c, and a surface layer 2d are sequentially stacked from the bottom around a cored bar (supporting member) 2a. The lower layer 2b is a foamed sponge layer for reducing charging noise, the intermediate layer 2c is a resistance layer for obtaining uniform resistance as a whole of the charging roller, and the surface layer 2d has defects such as pinholes on the photosensitive drum 1. This is a protective layer provided to prevent the occurrence of a leak even if it is present. The charging roller 2 of this example uses a stainless steel round bar having a diameter of 6 mm as the cored bar 2a, carbon is dispersed in a fluororesin as a surface layer, the outer diameter of the roller is 14 mm, and the roller resistance is 10 ⁴ Ω-10 ⁷ Ω.
[0056]
The charging roller 2 holds both ends of the cored bar 2a rotatably by bearing members, and urges the pressing roller toward the photosensitive drum 1 with a pressing spring to press the surface of the photosensitive drum 1 with a predetermined pressing force. The photosensitive drum 1 rotates following the rotation of the photosensitive drum 1. When a predetermined vibration voltage (bias voltage Vdc + Vac) obtained by superimposing an AC voltage having a frequency f on a DC voltage is applied from the power supply 20 to the charging roller 2 via the cored bar 2a, the peripheral surface of the rotating photosensitive drum 1 is changed. It is charged to a predetermined potential.
[0057]
In this embodiment, a DC voltage is -500 V, an AC voltage is a frequency f = 1150 Hz, a peak-to-peak voltage Vpp = 1400 V, and a vibration voltage in which a sine wave is superimposed. The peripheral surface of the photosensitive drum 1 is -500 V (dark potential Vd ) Is uniformly contact-charged.
[0058]
In FIG. 2, the charging roller cleaning member 2f is a flexible cleaning film. The cleaning film 2f is fixed at one end to a support member 2g which is arranged in parallel with the longitudinal direction of the charging roller 2 and reciprocates by a fixed amount in the longitudinal direction, and has a surface near the free end side. And a contact nip. The support member 2g is driven in a reciprocating motion by a predetermined amount in the longitudinal direction via a gear train by a drive motor of the printer, and the charging roller surface layer 2d is rubbed by the cleaning film 2f. As a result, contaminants (fine powder toner, external additives, etc.) adhered to the charging roller surface layer 2d are removed.
[0059]
After being uniformly charged to a predetermined polarity and potential by the charging roller 2, image exposure means (not shown) such as a color document image separation / imaging exposure optical system and a time-series electric digital pixel signal of image information An electrostatic latent image corresponding to a first color component image (yellow component image) in a target color image by receiving exposure light 3 from a laser scanning scanning exposure system that outputs a correspondingly modulated laser beam. Is formed. In this embodiment, a laser beam scanner using a semiconductor laser is used as an exposure device, and a laser beam modulated according to an image signal sent from a host device such as an image reading device (not shown) to the printer side is output. The uniformly charged surface of the rotating photosensitive drum 1 is subjected to laser scanning exposure (image exposure). As a result of the laser scanning exposure, the potential of the surface of the photosensitive drum 1 irradiated with the laser beam decreases, so that an electrostatic latent image corresponding to the scanned and exposed image information is formed on the surface of the rotating photosensitive drum 1. In this embodiment, the potential of the exposed portion is set to -150V.
[0060]
Next, the electrostatic latent image is developed by the first developing device 4 (yellow developing device) with the first color yellow toner.
[0061]
In FIG. 2, the yellow image formed on the photosensitive drum 1 enters a primary transfer nip portion with the intermediate transfer belt 9. In the transfer nip portion, a transfer roller 9 g is in contact with the back side of the intermediate transfer belt 9. The transfer roller 9g has primary transfer bias sources 9a to 9d so that a bias can be independently applied to each port. The intermediate transfer belt 9 first transfers yellow at the first color port, and then performs multiple transfer of each color of magenta, cyan, and black at each port sequentially from the photosensitive drum 1 corresponding to each color through the same process as described above. Next, the four-color full-color image formed on the intermediate transfer belt 9 is collectively transferred to the transfer material P sent from the paper feed roller 12 by the secondary transfer roller 10 and fused and fixed by a fixing device (not shown). Obtain a print image.
[0062]
The secondary transfer residual toner remaining on the intermediate transfer belt 9 is blade-cleaned by the intermediate transfer belt cleaner 11 to prepare for the next image forming process.
[0063]
In FIG. 1, a toner charging control unit 6 and a residual toner image uniforming unit 7 are in contact with the photosensitive drum 1. In both embodiments, a brush member made of conductive fiber is used in this embodiment. More specifically, the toner charging control means 6 has a horizontally long electrode plate 62 provided with a brush portion 61, and the residual toner uniforming means 7 also has an electrode plate 72 provided with a brush portion 71. Become. The brush portions 61 and 71 are arranged in contact with the surface of the photosensitive drum 1 so as to be fixedly supported. The brush portions 61 and 71 are made of fibers such as rayon, acrylic and polyester containing carbon or metal powder to control the resistance value. The brush portions 61 and 71 have a thickness of 30 denier or less and a density of 100,000 / 500,000 / inch so that the brush portions 61 and 71 can uniformly contact the photosensitive drum surface and the transfer residual toner. ² The above is preferable. In this embodiment, both the brush portions 61 and 71 have 6 deniers and 100,000 brushes / inch. ² The length of the bristle feet is 5mm and the brush resistance is 6 × 10 ³ Ω · cm. The toner charging control means 6 and the residual toner image equalizing means 7 are brought into contact with each other so that the brush portions 61 and 71 have a penetration amount of 1 mm with respect to the surface of the photosensitive drum 1. The width was 5 mm.
[0064]
In the present embodiment, a voltage of negative polarity is applied to the toner charging control unit 6 from the power supply 21. An AC voltage on which a DC voltage is superimposed is applied from a power supply 22 to the transfer residual toner image uniforming means 7.
[0065]
The DC bias of -700 V was applied to the toner charging control means 6, and the bias applied to the transfer residual toner image uniforming means 7 was a sine wave, Vpp = 400 V, frequency = 1150 Hz, and Vdc = + 250 V.
[0066]
【Example】
(Example 1)
The electrophotographic photoreceptor of the present invention uses an aluminum cylinder as a support, and a coating composed of the following materials is applied on the support by a dipping method, and thermally cured at 140 ° C. for 30 minutes to form a 15 μm conductive layer. Formed.
[0067]
Conductive pigment: SnO ₂ Coated barium sulfate 10 parts
Pigment for resistance adjustment: 2 parts of titanium oxide
Binder resin: 6 parts of phenolic resin
Leveling material: 0.001 part of silicone oil
Solvent: methanol / methoxypropanol = 0.2 / 0.8 20 parts
[0068]
Next, a solution prepared by dissolving 4.5 parts of N-methoxymethylated nylon and 1.5 parts of copolymerized nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol was applied thereon by an immersion method. Formed an intermediate layer having a thickness of 0.6 μm.
[0069]
Next, 3.5 parts of hydroxygallium phthalocyanine crystal having strong peaks at 7.4 ° and 28.2 ° of Bragg angles (2θ ± 0.2 °) in characteristic X-ray diffraction of CuKα and polyvinyl butyral resin (trade name) : SREC BH-S, manufactured by Sekisui Chemical Co., Ltd.) 1 part was added to 120 parts of cyclohexanone, dispersed by a sand mill using 1 mmφ glass beads for 3 hours, and diluted with 120 parts of methyl ethyl ketone for charge generation layer. A paint was prepared. On the undercoat layer, this charge generation layer paint was applied by dip coating, and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.15 μm.
[0070]
Next, 9 parts of an amine compound represented by the following formula,
[0071]
Embedded image

1 part of an amine compound represented by the following formula,
[0072]
Embedded image

10 parts of the compound (Mw = 75000) represented by Structural Unit Example (1-2) as a binder resin was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 50 parts of dichloromethane to obtain a coating solution for a charge transport layer. The coating solution was applied by a dip coating method and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 27 μm.
[0073]
The electrophotographic photoreceptor thus manufactured was mounted on the full-color electrophotographic apparatus shown in FIG. 2, and in the above-described charging setting, each environment of 23 ° C./60%, 15 ° C./10%, and 30 ° C./80%. A continuous durability test was performed on 20,000 full-color images under the following conditions.
[0074]
The evaluation was made focusing on four items: toner fusion of the electrophotographic photoreceptor, presence or absence of flaws, abrasion amount, and image characteristics. The results are shown in Table 1.
[0075]
The evaluation criteria for each evaluation item are as follows.
[0076]
(A) Fusion of toner on electrophotographic photoreceptor
A four-stage evaluation was performed visually. Evaluation criteria are
A: No toner fusion,
B: Slightly generated in the latter half of durability,
C: Occurs in the latter half of endurance,
D: Generated from the first half
[0077]
(B) Whether or not the electrophotographic photosensitive member is flawed
A four-stage evaluation was performed visually. Evaluation criteria are
A: No scratch,
B: Slightly generated in the latter half of durability,
C: Occurs in the latter half of endurance,
D: Generated from the first half of endurance
[0078]
(C) Abrasion amount of electrophotographic photoreceptor
The average abrasion amount of the surface layer of four electrophotographic photosensitive members per 10,000 sheets was examined by film thickness measurement using “Permascope E111” manufactured by Fisher (USA).
[0079]
(D) Image characteristics
Four-level evaluation by visual inspection. With respect to the evaluation standard, the uniformity, gradation, and fine line reproducibility of a solid black image were visually evaluated on a four-point scale based on the original document.
[0080]
A: Excellent, B: Good, C: Normal, D: Poor
[0081]
(Example 2)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the structural unit example (1-4) (Mw = 78000) was used as the binder resin for the charge transport layer, and the same evaluation as in Example 1 was performed. Was. The results are shown in Table 1.
[0082]
(Example 3)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the structural unit example (1-6) (Mw = 70000) was used as the binder resin for the charge transport layer, and the same evaluation as in Example 1 was performed. Was. The results are shown in Table 1.
[0083]
(Example 4)
Electrophotography was carried out in the same manner as in Example 1, except that the binder resin for the charge transport layer was a copolymer (Mw = 80000) consisting of structural unit examples (1-2) / (2-4) = 30/70. A photoreceptor was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0084]
(Example 5)
Electrophotography was performed in the same manner as in Example 1 except that the binder resin for the charge transport layer was a copolymer (Mw = 78000) composed of structural unit examples (1-2) / (2-4) = 50/50. A photoreceptor was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0085]
(Example 6)
Electrophotography was carried out in the same manner as in Example 1, except that the binder resin for the charge transport layer was a copolymer (Mw = 75000) composed of structural unit examples (1-2) / (2-4) = 70/30. A photoreceptor was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0086]
(Examples 7 to 12)
In the electrophotographic photoreceptors of Examples 1 to 6, the procedure was carried out except that 0.2 parts of a comb type silicone graft polymer (trade name: Alon GS-101CP, manufactured by Toagosei Chemical Industry Co., Ltd.) was added to the charge transport layer. An electrophotographic photosensitive member was prepared in the same manner as in Examples 1 to 6, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.
[0087]
(Examples 13 to 18)
In the electrophotographic photoreceptors of Examples 1 to 6, the same as Examples 1 to 6 except that one part of a tetrafluoroethylene resin (trade name: Lubron L2, manufactured by Daikin Industries, Ltd.) was dispersed in the charge transport layer. Then, an electrophotographic photosensitive member was manufactured, and the same evaluation as in Example 1 was performed. The results are shown in Table 2.
[0088]
(Examples 19 to 24)
In the electrophotographic photoreceptors of Examples 7 to 12, 9.5 parts of the arylate resin and the silicone-modified polycarbonate resin represented by the formulas (5), (6) and (7) {the total mass of the copolymer represented by the formula (5)} 45% by mass of the copolymer having the formula (6) of 45% by mass (viscosity average molecular weight 2.21 × 10 ⁴ An electrophotographic photoreceptor was prepared in the same manner as in Examples 7 to 12, except that｝ was changed to 0.5 part, and the same evaluation as in Example 1 was performed. The results are shown in Table 2.
[0089]
(Comparative Example 1)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1, except that the polycarbonate resin (trade name: Iupilon Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used as the binder resin for the charge transport layer in Example 1. Then, the same evaluation was performed. The results are shown in Table 2.
[0090]
(Comparative Example 2)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that a polycarbonate resin (Teijin Panlite L-1250, manufactured by Teijin Chemicals Ltd.) was used as the binder resin for the charge transport layer in Example 1. The same evaluation as in Example 1 was performed. The results are shown in Table 2.
[0091]
(Comparative Example 3)
Example 1 was evaluated in the same manner as in Example 1 except that only a high DC voltage was applied to the residual developer image uniforming means.
[0092]
As a result, although the drum was scraped and no flaw was generated, a normal output image could not be obtained due to the influence of the transfer residual toner that did not collect the output image. For this reason, fusion occurred. The results are shown in Table 2.
[0093]
[Table 1]

[0094]
[Table 2]

[0095]
【The invention's effect】
As described above, according to the present invention, there is provided an electrophotographic apparatus which applies an AC high voltage in which a DC high voltage is superimposed on a residual developer image uniforming means, and applies the DC voltage having the predetermined polarity to the developer charge amount controlling means. When the electrophotographic photosensitive member used in the electrophotographic apparatus contains a specific polyarylate resin structural unit, problems such as fusion, flaws, and scraping can be solved.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an electrophotographic apparatus according to the present invention.
FIG. 2 is a schematic sectional view of a full-color electrophotographic apparatus of the present invention.
[Explanation of symbols]
1. Electrophotographic photoreceptor
2 Charging device
3 Exposure light
4 Developing device
5 T-CRG
6 Developer charge control means
7 Means for equalizing residual transfer developer image
8 Process cartridge
9 Intermediate transfer belt
10 Secondary transfer roller
11 Intermediate transfer belt cleaner
12 Paper feed roller
20, 21, 22 power supply

Claims (12)

An electrophotographic photosensitive member, a charging unit for charging the electrophotographic photosensitive member surface, an information writing unit for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and a developer having a predetermined polarity applied to the electrostatic latent image. Developing means for supplying and visualizing the electrostatic latent image, transfer means for transferring the visualized developer image to a transfer material, and a developer which is located upstream of the charging means and charges the developer on the electrophotographic photosensitive member surface Charge amount control means, and a residual developer image which is located upstream of the developer charge amount control means and downstream of the transfer means and which remains on the electrophotographic photosensitive member surface after transferring the developer image to a transfer material. Means for equalizing the residual developer image, and applying an AC high voltage on which a DC high voltage is superimposed to the residual developer image uniformizing means, and applying the DC voltage of the predetermined polarity to the developer charge amount controlling means. The electrophotographic photoreceptor Formula (1), an electrophotographic apparatus characterized in that it contains at least one structural unit of the polyarylate resin represented by (2).

(Wherein X is —CR ⁵ R ⁶ — (wherein R ⁵ and R ⁶ are each independently a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms) ), An optionally substituted 1,1-cycloalkylene group having 5 to 11 carbon atoms, an α, ω-alkylene group having 2 to 10 carbon atoms, a single bond, -O-, -S-, -SO- or- SO ₂ -.. is ^also, R 1 to R ⁴ is a hydrogen atom, a halogen atom, an alkyl group or an aryl group having 1 to 3 carbon atoms, provided that at least ^{R 1} and one ^{R 2,} and at least ^{R 3} And one of R ⁴ is other than a hydrogen atom)

(Wherein, R ^{7 to} R ¹⁰ are a hydrogen atom, an alkyl group or an aryl group having 1 to 3 carbon atoms, provided that at least one of R ⁷ and R ⁸ and at least one of R ⁹ and R ¹⁰ are Other than hydrogen atom) 2. The electrophotographic apparatus according to claim 1, wherein a structural unit represented by Formula (1) for forming a photosensitive layer of the electrophotographic photosensitive member is represented by Formula (3) below. 3.

The electrophotographic apparatus according to claim 1, wherein the structural unit represented by the formula (2) for forming the photosensitive layer of the electrophotographic photoreceptor is the following formula (4).

4. The electrophotographic apparatus according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains a comb-type silicone graft polymer. The electrophotographic apparatus according to claim 4, wherein the comb type silicone graft polymer is a silicone-modified polycarbonate resin. The electrophotographic apparatus according to claim 5, wherein the silicone-modified polycarbonate resin is a copolymer of the structural units represented by the following formulas (5), (6) and (7).

The electrophotographic apparatus according to any one of claims 1 to 6, wherein the surface layer of the electrophotographic photosensitive member contains a fluororesin powder. 8. An electrophotographic apparatus according to claim 1, wherein said charging means is of a contact charging type. The electrophotographic apparatus according to claim 1, wherein an oscillating electric field is applied to the charging unit. 2. The image forming apparatus according to claim 1, further comprising: a plurality of electrophotographic photosensitive members each carrying a plurality of color developer images; An electrophotographic apparatus according to any one of claims 1 to 9. An electrophotographic photosensitive member used for the electrophotographic apparatus according to claim 1. An electrophotographic photoreceptor according to claim 11, and at least one unit selected from the group consisting of a charging unit, a developer charge amount controlling unit, a residual developer image uniforming unit, and a developing unit. A process cartridge which is detachable from a photographic apparatus main body.

Images