JP3761990B2 - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Description

（式中、Ｘは−ＣＲ₁₃Ｒ₁₄−（Ｒ₁₃及びＲ₁₄は水素原子、置換されてもよいそれぞれアルキル基またはアリール基、またはＲ₁₃とＲ₁₄にわたる２価のアルキリデン基である）、置換されてもよいそれぞれアルキレン基またはフルオレン基、単結合、−Ｏ−、−Ｓ−、−ＳＯ−、または−ＳＯ₂ −である。また、Ｒ₁ 〜Ｒ₁₂は水素原子、ハロゲン原子、置換されてもよいそれぞれアルキル基またはアリール基である。）
また、本発明は、上記電子写真感光体を有するプロセスカートリッジ及び電子写真装置である。
【００２７】
【発明の実施の形態】
本発明における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、アルキレン基としてはメチレン基及びジメチレン基等が挙げられ、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。Ｒ₁₃とＲ₁₄にわたる２価のアルキリデン基としてはシクロヘキシリデン基及びシクロペンチリデン基等が挙げられ、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。これらが有してもよい置換基としては上述のようなハロゲン原子、アルキル基及びアリール基等が挙げられる。
【００２８】
以下に式（１）で示される構成単位の具体例を表１で示すが、これらに限られるものではない。
【００２９】
【表１】

【００３０】
【表２】

【００３１】
【表３】

【００３２】
好ましい例としては構成単位例１、２、３及び７が挙げられ、特に構成単位１及び２が好ましい。
【００３３】
本発明において用いられる式（１）で示される構成単位を有する重合体は、下記式（２）で示されるビスフェノールを通常溶解性を上げるためテレフタル酸塩化物及びイソフタル酸塩化物の混合物とアルカリ下で溶媒／水系中で撹拌して界面重合によって合成できる。
【００３４】
テレフタル酸塩化物及びイソフタル酸塩化物の比率はその重合体の溶解性を考慮して決定されるもので定説はない。ただし、いずれかの塩化物が３０ｍｏｌ％以下になると合成した重合体の溶解性が極端に低下するので注意が必要である。通常は１／１の比率で合成するのが好ましい。
【００３５】
【化３】

（式中、Ｘは−ＣＲ₁₃Ｒ₁₄−（Ｒ₁₃及びＲ₁₄は水素原子、置換されてもよいそれぞれアルキル基またはアリール基、またはＲ₁₃とＲ₁₄にわたる２価のアルキリデン基である）、置換されてもよいそれぞれアルキレン基またはフルオレン基、単結合、−Ｏ−、−Ｓ−、−ＳＯ−、または−ＳＯ₂ −である。また、Ｒ₁ 〜Ｒ₈ は水素原子、ハロゲン原子、置換されてもよいそれぞれアルキル基またはアリール基である。）
本発明の電子写真感光体においては式（１）で示される構成単位が同一のもので構成される重合体でも、２種類以上の式（１）で示される別種の構成単位からなる共重合体でもよい。
【００３６】
本発明による電子写真感光体は特に優れた耐ソルベントクラック性と機械的強度とＡＣ帯電における耐電気特性を合わせ持ち、良好な電子写真特性を持っているものである。
【００３７】
本発明による重合体は構成単位中に剛直性を有するユニットが含有され、電子写真感光体形成時にそのユニットが部分的にガラス化することによって高分子被膜全体の耐久性を上げるものである。
【００３８】
またこの分子内部における部分的ガラス化により分子内密度を上げかつ非晶質部分と結晶質部分を同一分子内に併せ持つため塗膜形成時に発生する分子内応力をも緩和することができ、それによりソルベントクラックの要因となる薬品が侵入しても内部応力を維持しクラックが生じないと推定される。
【００３９】
機械的強度は結晶質部分の存在により強固になるものと推測される。
【００４０】
耐電気特性においては、カーボネート結合に比較してアリール基のエステル結合であるアリレート構造はＡＣ帯電による電流に強く特に耐電気性能が上がっていると考えられる。この理由は確認されていないがカーボネート結合はカルボキシ基の両側に酸素原子があるためダイポールモーメントが大きく電気エネルギーに対して弱いためと推測される。
【００４１】
以下本発明に用いる電子写真感光体の構成について説明する。
【００４２】
本発明における電子写真感光体は、感光層が電荷輸送材料と電荷発生材料を同一の層に含有する単層型であっても、電荷輸送層と電荷発生層に分離した積層型でもよいが電子写真特性的には積層型が好ましい。
【００４３】
使用する導電性支持体は導電性を有するものであればよく、アルミニウム、ステンレス等の金属、あるいは導電層を設けた金属、紙及びプラスチック等が挙げられ、形状はシート状及び円筒状等が挙げられる。
【００４４】
ＬＢＰ等画像入力がレーザー光の場合は散乱による干渉縞防止、または支持体の傷を被覆することを目的とした導電層を設けてもよい。これは、カーボンブラック及び金属粒子等の導電性粉体をバインダー樹脂に分散させて形成することができる。導電層の膜厚は５〜４０μｍが好ましく、より好ましくは１０〜３０μｍである。
【００４５】
その上に接着機能を有する中間層を設ける。中間層の材料としてはポリアミド、ポリビニルアルコール、ポリエチレンオキシド、エチルセルロース、カゼイン、ポリウレタン及びポリエーテルウレタン等が挙げられる。これらは適当な溶剤に溶解して塗布される。中間層の膜厚は０．０５〜５μｍが好ましく、より好ましくは０．３〜１μｍである。
【００４６】
中間層の上には電荷発生層が形成される。本発明に用いられる電荷発生物質としてはセレン−テルル、ピリリウム、チアピリリウム系染料、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、キナクリドン及び非対称キノシアニン系の各顔料が挙げられる。機能分離型の場合、電荷発生層は前記電荷発生物質を０．３〜４倍量のバインダー剤樹脂及び溶剤とともにホモジナイザー、超音波分散、ボールミル、振動ボールミル、サンドミル、アトライター、ロールミル及び液衝突型高速分散機等の方法でよく分散し、分散液を塗布、乾燥させて形成される。電荷発生層の膜厚は５μｍ以下が好ましく、より好ましくは０．１〜２μｍである。
【００４７】
電荷輸送層は主として電荷輸送材料と本発明に用いる重合体を含むバインダー樹脂とを溶剤中に溶解させた塗料を塗工・乾燥して形成する。用いられる電荷輸送材料としてはトリアリールアミン系化合物、ヒドラゾン化合物、スチルベン化合物、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。
【００４８】
これらは０．５〜２倍量のバインダー樹脂と組み合わされ塗工、乾燥し電荷輸送層を形成する。電荷輸送層の膜厚は５〜４０μｍが好ましく、より好ましくは１５〜３０μｍである。
【００４９】
図１に本発明の電子写真感光体を有するプロセスカートリッジを有する電子写真装置の概略構成を示す。
【００５０】
図において、１はドラム状の本発明の電子写真感光体であり、軸２を中心に矢印方向に所定の周速度で回転駆動される。感光体１は、回転過程において、一次帯電手段３によりその周面に正または負の所定電位の均一帯電を受け、次いで、スリット露光やレーザービーム走査露光等の像露光手段（不図示）からの画像露光光４を受ける。こうして感光体１の周面に静電潜像が順次形成されていく。
【００５１】
形成された静電潜像は、次いで現像手段５によりトナー現像され、現像されたトナー現像像は、不図示の給紙部から感光体１と転写手段６との間に感光体１の回転と同期取り出されて給紙された転写材７に、転写手段６により順次転写されていく。
【００５２】
像転写を受けた転写材７は、感光体面から分離されて像定着手段８へ導入されて像定着を受けることにより複写物（コピー）として装置外へプリントアウトされる。
【００５３】
像転写後の感光体１の表面は、クリーニング手段９によって転写残りトナーの除去を受けて清浄面化され、更に前露光手段（不図示）からの前露光光１０により除電処理された後、繰り返し像形成に使用される。なお、一次帯電手段３が帯電ローラー等を用いた接触帯電手段である場合は、前露光は必ずしも必要ではない。
【００５４】
本発明においては、上述の電子写真感光体１、一次帯電手段３、現像手段５及びクリーニング手段９等の構成要素のうち、複数のものをプロセスカートリッジとして一体に結合して構成し、このプロセスカートリッジを複写機やレーザービームプリンター等の電子写真装置本体に対して着脱可能に構成してもよい。例えば、一次帯電手段３、現像手段５及びクリーニング手段９の少なくともひとつを感光体１と共に一体に支持してカートリッジ化して、装置本体のレール１２等の案内手段を用いて装置本体に着脱可能なプロセスカートリッジ１１とすることができる。
【００５５】
また、画像露光光４は、電子写真装置が複写機やプリンターである場合には、原稿からの反射光や透過光、あるいは、センサーで原稿を読取り、信号化し、この信号に従って行われるレーザービームの走査、ＬＥＤアレイの駆動及び液晶シャッターアレイの駆動等により照射される光である。
【００５６】
本発明の電子写真感光体は電子写真複写機に利用するのみならず、レーザービームプリンター、ＣＲＴプリンター、ＬＥＤプリンター、液晶プリンター及びレーザー製版等電子写真応用分野にも広く用いることができる。
【００５７】
以下実施例に従って説明する。実施例中部は重量部を表わす。
【００５８】
〔実施例１〕
３０φ、２５４ｍｍの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コーティング法で塗布し１４０℃で３０分熱硬化して１５μｍの導電層を形成した。
【００５９】
導電性顔料：ＳｎＯ₂ 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
【００６０】
次に、この上にＮ−メトキシメチル化ナイロン３部及び共重合ナイロン３部をメタノール６５部及びｎ−ブタノール３０部の混合溶媒に溶解した溶液を浸漬コーティング法で塗布し０．５μｍの中間層を形成した。
【００６１】
次に、ＣｕＫα特性Ｘ線回折のブラッグ角２θ±０．２°が９．０°、１４．２°、２３．９°及び２７．１°に強いピークを有するオキシチタニウムフタロシアニン（ＴｉＯＰｃ）４部及びポリビニルブチラール（商品名：エスレックＢＭ２、積水化学製）２部及びシクロヘキサノン６０部をφ１ｍｍガラスビーズを用いたサンドミル装置で４時間分散した後、エチルアセテート１００部を加えて電荷発生層用分散液を調製した。これを浸漬コーティング法で塗布し０．３μｍの電荷発生層を形成した。
【００６２】
次に、下記構造式のアミン化合物５部、
【００６３】
【化４】

下記構造式のアミン化合物５部
【００６４】
【化５】

と表２の条件１記載の重合体１０部を、モノクロロベンゼン３０部及びジクロロメタン７０部の混合溶媒に溶解した。
【００６５】
この重合体は所定ビフェノール（０．０１ｍｏｌ）、水酸化ナトリウム（０．８ｇ）及び塩化テトラメチルアンモニウム（１ｇ）を水１００ｍｌに溶かして１リットルのミキサー中に投入し、これに１，２−ジクロロエタン（３０ｍｌ）にテレフタル酸塩化物（０．００５ｍｏｌ）及びイソフタル酸塩化物（０．００５ｍｏｌ）を溶かしたものを撹拌しながら投入し１０分高速撹拌し２時間放置後、１，２−ジクロロエタン液を回収しこれに大量のヘキサンを投入しポリマーとして回収したものである。なお、回収後水洗浄、クロロホルム溶解及びメタノール滴下による精製工程後に十分乾燥したものを用いた。
【００６６】
回収したポリマーについてはカールフィッシャー法により水分量の測定を行った。表２の条件１記載の重合体の水分量は１．８ｍｇＨ₂ Ｏ／１ｇであった。
【００６７】
この塗料を浸漬コーティング法で塗布し、１２０℃で２時間乾燥して２５μｍの電荷輸送層を形成した。
【００６８】
次に評価について説明する。
【００６９】
装置はキヤノン製レーザービームプリンター「レーザーショットＡ４０４」を改造した装置に取り付け、３２℃、９５％ＲＨ下で５０００枚の連続耐久を行った。装置は非照射時の暗部の帯電電位Ｖｄを−６５０Ｖ、レーザー光照射時の電位Ｖｌを−１７０Ｖとなるように設定した。
【００７０】
評価は耐久前後の非照射時の暗部の帯電電位Ｖｄ、レーザー光照射時の電位Ｖｌ、前露光後の残留電位Ｖｓｌを測定すると同時に、耐久前のみべた白画像を出力し、カブリ（黒ポチ）の程度を１（軽微）〜５（多数発生）の５ランクに分類することにより行った。結果を表３に示す。
【００７１】
【表４】

テレフタル酸塩化物とイソフタル酸塩化物の混合比はモル比で１：１とした。
［実施例２〜１２］
電荷輸送層のバインダー樹脂に表２の条件２〜１２のものを用いた以外は、実施例１と同様に電子写真感光体を作成し評価した。その結果を表３に示す。
【００７２】
【表５】

［比較例１〜５］
電荷輸送層のバインダー樹脂に表４の条件１から５のものを用いた以外は、実施例１と同様に電子写真感光体を作成し評価した。その結果を表５に示す。
【００７３】
【表６】

【００７４】
【表７】

【００７５】
【発明の効果】
本発明の電子写真感光体は、機械的強度を損なうことなく優れた耐ソルベントクラック性を有し、かつ直接帯電による放電に対する耐電気特性の向上に有効であることに加えて、カブリと残留電位が小さい特性を備えた製造が容易で直接帯電に適した電子写真感光体、及び該電子写真感光体を有するプロセスカートリッジ及び電子写真装置を提供することが可能となった。
【図面の簡単な説明】
【図１】本発明の電子写真感光体を有するプロセスカートリッジを有する電子写真装置の概略構成の例を示す図である。
【符号の説明】
１ 本発明の電子写真感光体
２ 軸
３ 一次帯電手段
４ 画像露光光
５ 現像手段
６ 転写手段
７ 転写材
８ 像定着手段
９ クリーニング手段
１０ 前露光光
１１ プロセスカートリッジ
１２ レール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus, and more specifically, an electrophotographic photosensitive member having a surface layer containing a specific resin, and a process having the electrophotographic photosensitive member. The present invention relates to a cartridge and an electrophotographic apparatus.
[0002]
[Prior art]
In the electrophotographic method, as shown in U.S. Pat. No. 2,297,691, the electrical resistance changes depending on the amount of irradiation received during image exposure, and in the dark place is a photoconductive material comprising a support coated with an insulating material. Use materials. Basic characteristics required for an electrophotographic photosensitive member using this photoconductive material are (1) that it can be charged to an appropriate potential in a dark place, (2) little potential dissipation in a dark place, and (3 ) Quickly dissipate charges by light irradiation.
[0003]
Conventionally, as an electrophotographic photosensitive member, an inorganic photosensitive member having a photosensitive layer mainly composed of an inorganic photoconductive compound such as selenium, zinc oxide and cadmium sulfide has been widely used. However, these satisfy the above conditions (1) to (3) but are not necessarily satisfactory in terms of thermal stability, moisture resistance, durability and productivity.
[0004]
In order to overcome the disadvantages of inorganic photoreceptors, electrophotographic photoreceptors based on various organic photoconductive compounds as main components have been actively developed in recent years. For example, US Pat. No. 3,378,851 discloses a photoreceptor having a charge transport layer containing triallylpyrazoline, US Pat. No. 3,871,880 discloses a charge generation layer comprising a derivative of perylene pigment, and a condensate of 3-propylene and formaldehyde. A photoconductor comprising a charge transport layer comprising, is known.
[0005]
Further, the organic photoconductive compound can freely select the photosensitive wavelength range of the electrophotographic photosensitive member depending on the compound. For example, in the case of an azo pigment, Japanese Patent Laid-Open Nos. 61-272754 and 56-167759 are disclosed. The gazette discloses substances having high sensitivity in the visible region, and JP-A 57-19576 and JP-A 61-228453 show compounds having sensitivity up to the infrared region. Yes.
[0006]
Among these materials, those showing sensitivity in the infrared region are used in laser beam printers (hereinafter abbreviated as LBP) and LED printers that have made remarkable progress in recent years, and the frequency of demand thereof has increased.
[0007]
Electrophotographic photoreceptors using these organic photoconductive compounds are sometimes used as functionally separated photoreceptors in which a charge transport layer and a charge generation layer are laminated in order to satisfy both electrical and mechanical properties. Many. On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, and optical characteristics according to the applied electrophotographic process.
[0008]
In particular, in electrophotographic photoreceptors that are used repeatedly, electrical and mechanical external forces such as corona or direct charging, image exposure, toner development, transfer process and surface cleaning are directly applied to the surface of the electrophotographic photoreceptor. Durability is also required.
[0009]
Specifically, electrical deterioration due to ozone and nitrogen oxides during charging, discharge during charging, mechanical deterioration in which the surface is worn or scratched by rubbing of the cleaning member, durability against electrical deterioration Is required.
[0010]
The electrical deterioration is particularly a phenomenon in which a carrier is accumulated in a portion irradiated with light and a potential difference is generated from a portion not irradiated with light, which occurs as a photo memory.
[0011]
Unlike the inorganic photoreceptors, organic photoreceptors that are often soft in material are inferior in durability against mechanical deterioration and are particularly desired to be improved in durability.
[0012]
Various attempts have been made to satisfy the durability characteristics required for the photoreceptor as described above.
[0013]
Polycarbonate resin with bisphenol A as a skeleton is attracting attention as a resin that is often used for the surface layer and has good wear and electrical properties. Has a point.
[0014]
(1) It has poor solubility and exhibits good solubility only in a part of halogenated aliphatic hydrocarbons such as dichloromethane and 1,2-dichloroethane, and these solvents have low boiling points. When a photoreceptor is manufactured using the prepared coating solution, the coated surface is likely to be whitened. It also takes time to manage the solid content of the coating liquid.
[0015]
(2) Solvents other than halogenated aliphatic hydrocarbons are partially soluble in tetrahydrafuran, dioxane, cyclohexanone or mixed solvents thereof, but the solution gels in several days. Inferior in properties and unsuitable for photoconductor production.
[0016]
(3) Furthermore, even if the above formulas (1) and (2) are improved, solvent cracks are likely to occur in the polycarbonate resin having bisphenol A as a skeleton.
[0017]
(4) In addition, with conventional polycarbonate resins, the film formed with the resin has no lubricity, so the photoreceptor is easily damaged, and toner fusion is used in a cleaning setting that reduces the amount of wear of the electrophotographic photoreceptor. In some cases, image defects such as the above, or defective cleaning due to early deterioration of the cleaning blade, toner fusion, and the like may occur.
[0018]
The solution stability mentioned in the above (1) and (2) can be solved by using a polycarbonate Z resin having a bulky cyclohexylene group as a polymer structural unit, or by copolymerizing with bisphenol Z, bisphenol C or the like. I came.
[0019]
Solvent cracks can also be solved by using siloxane-modified polycarbonate or ether-modified polycarbonate as disclosed in JP-A-6-51544 and JP-A-6-75415. However, these modified polycarbonates have a structure that is more flexible against internal stress in the polymer in order to prevent solvent cracks than conventional polycarbonate resins, resulting in the mechanical properties of the polymer body. There was a drawback that the strength decreased.
[0020]
Further, in recent years, a direct charging method in which a voltage is directly applied to a charging member and a charge is applied to an electrophotographic photosensitive member as disclosed in Japanese Patent Application Laid-Open Nos. 57-17826 and 58-40566 has become mainstream. It's getting on.
[0021]
This is a method in which a roller-shaped charging member made of conductive rubber or the like is directly brought into contact with the electrophotographic photosensitive member to apply a charge. Compared with a scorotron or the like, the amount of ozone generated is significantly smaller. Around 80% of the current flowing through the capacitor is wasted because it flows through the shield, whereas direct charging has the merit of being very economical because there is no waste.
[0022]
However, direct charging has a drawback that charging stability is very poor because of charging by discharge according to Paschen's law. As a countermeasure, a so-called AC / DC charging system in which an AC voltage is superimposed on a DC voltage has been devised (Japanese Patent Laid-Open No. 63-149668).
[0023]
Although this charging method has improved the stability during charging, the amount of discharge on the surface of the electrophotographic photosensitive member is greatly increased due to the superimposition of AC, so that the amount of abrasion of the electrophotographic photosensitive member is increased. As a result, not only mechanical strength but also electrical strength has been required.
[0024]
[Problems to be solved by the invention]
The object of the present invention is to solve the problems in the case of having a conventional polycarbonate resin as a surface layer, to have excellent solvent crack resistance, strong mechanical strength, and good electric resistance characteristics by direct charging. It is an object to provide an electrophotographic photosensitive member that is small in fog and residual potential and easy to manufacture, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[0025]
[Means for Solving the Problems]
That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member has a water content of 2.5 mgH ₂ O / 1 g or less. An electrophotographic photoreceptor, characterized by being a coating film of a paint in which a polyarylate resin having a repeating unit represented by the formula (1) is dissolved in an organic solvent .
[0026]
[Chemical 2]

Wherein X is —CR ₁₃ R ₁₄ — (R ₁₃ and R ₁₄ are each a hydrogen atom, an alkyl group or an aryl group which may be substituted, or a divalent alkylidene group extending over R ₁₃ and R ₁₄ ), Each of which may be substituted is an alkylene group or a fluorene group, a single bond, —O—, —S—, —SO—, or —SO ₂ —, wherein R _{1 to} R ₁₂ are hydrogen atoms, halogen atoms, substituted Each of which may be an alkyl group or an aryl group.)
The present invention also provides a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the alkyl group in the present invention include a methyl group, an ethyl group, and a propyl group, examples of the alkylene group include a methylene group and a dimethylene group, and examples of the aryl group include a phenyl group and a naphthyl group. Examples of the divalent alkylidene group extending over R ₁₃ and R ₁₄ include a cyclohexylidene group and a cyclopentylidene group, and examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. Examples of the substituent that they may have include a halogen atom, an alkyl group, and an aryl group as described above.
[0028]
Specific examples of the structural unit represented by the formula (1) are shown in Table 1 below, but are not limited thereto.
[0029]
[Table 1]

[0030]
[Table 2]

[0031]
[Table 3]

[0032]
Preferred examples include structural unit examples 1, 2, 3 and 7, with structural units 1 and 2 being particularly preferred.
[0033]
The polymer having the structural unit represented by the formula (1) used in the present invention is usually an alkaline solution with a mixture of terephthalic acid chloride and isophthalic acid chloride to improve the solubility of the bisphenol represented by the following formula (2). Can be synthesized by interfacial polymerization with stirring in a solvent / water system.
[0034]
The ratio of terephthalic acid chloride and isophthalic acid chloride is determined in consideration of the solubility of the polymer and has no established theory. However, care should be taken because the solubility of the synthesized polymer is extremely lowered when any of the chlorides is 30 mol% or less. Usually, it is preferable to synthesize at a ratio of 1/1.
[0035]
[Chemical 3]

Wherein X is —CR ₁₃ R ₁₄ — (R ₁₃ and R ₁₄ are each a hydrogen atom, an alkyl group or an aryl group which may be substituted, or a divalent alkylidene group extending over R ₁₃ and R ₁₄ ), Each of which may be substituted is an alkylene group or a fluorene group, a single bond, —O—, —S—, —SO—, or —SO ₂ —, and R _{1 to} R ₈ are each a hydrogen atom, a halogen atom, or a substituent. Each of which may be an alkyl group or an aryl group.)
In the electrophotographic photoreceptor of the present invention, even a polymer composed of the same structural unit represented by the formula (1) is a copolymer composed of two or more different structural units represented by the formula (1) But you can.
[0036]
The electrophotographic photosensitive member according to the present invention has particularly excellent solvent crack resistance, mechanical strength, and electric resistance in AC charging, and has good electrophotographic characteristics.
[0037]
The polymer according to the present invention contains a unit having rigidity in the structural unit, and the unit is partially vitrified at the time of forming the electrophotographic photosensitive member, thereby increasing the durability of the entire polymer film.
[0038]
In addition, the partial vitrification inside the molecule increases the intramolecular density and also has both an amorphous part and a crystalline part in the same molecule. It is presumed that even if chemicals that cause solvent cracks enter, internal stress is maintained and cracks do not occur.
[0039]
It is presumed that the mechanical strength becomes stronger due to the presence of the crystalline part.
[0040]
In terms of electrical resistance, it is considered that the arylate structure, which is an ester bond of an aryl group, is more resistant to current due to AC charging and has higher electrical resistance than carbonate bonds. The reason for this has not been confirmed, but it is presumed that the carbonate bond has oxygen atoms on both sides of the carboxy group, so that the dipole moment is large and weak against electric energy.
[0041]
The structure of the electrophotographic photoreceptor used in the present invention will be described below.
[0042]
The electrophotographic photosensitive member in the present invention may be a single layer type in which the photosensitive layer contains the charge transport material and the charge generation material in the same layer, or a stacked type in which the charge transport layer and the charge generation layer are separated. In view of photographic characteristics, a laminated type is preferable.
[0043]
Any conductive support may be used as long as it has conductivity. Examples thereof include metals such as aluminum and stainless steel, metals provided with a conductive layer, paper, plastics, and the like. It is done.
[0044]
When the image input such as LBP is laser light, a conductive layer may be provided for the purpose of preventing interference fringes due to scattering or covering a scratch on the support. This can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The film thickness of the conductive layer is preferably 5 to 40 μm, more preferably 10 to 30 μm.
[0045]
An intermediate layer having an adhesive function is provided thereon. Examples of the material for the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are dissolved in an appropriate solvent and applied. The film thickness of the intermediate layer is preferably 0.05 to 5 μm, more preferably 0.3 to 1 μm.
[0046]
A charge generation layer is formed on the intermediate layer. Examples of the charge generating material used in the present invention include selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanine, anthanthrone, dibenzpyrenequinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments. It is done. In the case of the function separation type, the charge generation layer is composed of the charge generation material 0.3 to 4 times the amount of binder resin and solvent, homogenizer, ultrasonic dispersion, ball mill, vibration ball mill, sand mill, attritor, roll mill and liquid collision type. It is well dispersed by a method such as a high-speed disperser, and is formed by applying and drying the dispersion. The film thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 to 2 μm.
[0047]
The charge transport layer is formed by applying and drying a paint in which a charge transport material and a binder resin containing the polymer used in the present invention are dissolved in a solvent. Examples of the charge transport material used include triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, triallylmethane compounds, and thiazole compounds.
[0048]
These are combined with 0.5 to 2 times the amount of the binder resin, coated and dried to form a charge transport layer. The thickness of the charge transport layer is preferably 5 to 40 μm, more preferably 15 to 30 μm.
[0049]
FIG. 1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention.
[0050]
In the figure, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotated about a shaft 2 in the direction of an arrow at a predetermined peripheral speed. In the rotation process, the photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the primary charging unit 3, and then from an image exposure unit (not shown) such as slit exposure or laser beam scanning exposure. The image exposure light 4 is received. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor 1.
[0051]
The formed electrostatic latent image is then developed with toner by the developing unit 5, and the developed toner developed image is rotated between the photosensitive member 1 and the transfer unit 6 from a sheet feeding unit (not shown). The image is sequentially transferred by the transfer means 6 to the transfer material 7 that is synchronously taken out and fed.
[0052]
The transfer material 7 that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means 8, and subjected to image fixing, thereby being printed out as a copy (copy).
[0053]
After the image transfer, the surface of the photoreceptor 1 is cleaned by removing the transfer residual toner by the cleaning unit 9 and further subjected to charge removal processing by the pre-exposure light 10 from the pre-exposure unit (not shown), and then repeatedly. Used for imaging. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.
[0054]
In the present invention, a plurality of components such as the electrophotographic photosensitive member 1, the primary charging unit 3, the developing unit 5 and the cleaning unit 9 described above are integrally coupled as a process cartridge. May be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, a process in which at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported together with the photoreceptor 1 to form a cartridge and can be attached to and detached from the apparatus main body using guide means such as a rail 12 of the apparatus main body. The cartridge 11 can be obtained.
[0055]
Further, when the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 is a reflected light or transmitted light from a document, or a signal is read out from a document by a sensor, and a laser beam performed according to this signal. Light emitted by scanning, LED array driving, liquid crystal shutter array driving, and the like.
[0056]
The electrophotographic photosensitive member of the present invention can be used not only in electrophotographic copying machines but also widely in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.
[0057]
A description will be given below in accordance with examples. The middle part of the examples represents parts by weight.
[0058]
[Example 1]
A 30 mm, 254 mm aluminum cylinder was used as a support, and a coating composed of the following materials was applied on the support by a dip coating method and thermally cured at 140 ° C. for 30 minutes to form a 15 μm conductive layer.
[0059]
Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: Titanium oxide 2 parts Binder resin: Phenol resin 6 parts Leveling material: Silicone oil 0.001 part Solvent: Methanol, methoxypropanol 0.2 / 0.8 20 copies [0060]
Next, a solution in which 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon were dissolved in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol was applied by dip coating, and a 0.5 μm intermediate layer was applied. Formed.
[0061]
Next, 4 parts of oxytitanium phthalocyanine (TiOPc) in which the Bragg angle 2θ ± 0.2 ° of CuKα characteristic X-ray diffraction has strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° And 2 parts of polyvinyl butyral (trade name: ESREC BM2, manufactured by Sekisui Chemical Co., Ltd.) and 60 parts of cyclohexanone were dispersed in a sand mill apparatus using φ1 mm glass beads for 4 hours, and then 100 parts of ethyl acetate was added to prepare a dispersion for charge generation layer. Prepared. This was applied by a dip coating method to form a 0.3 μm charge generation layer.
[0062]
Next, 5 parts of an amine compound of the following structural formula,
[0063]
[Formula 4]

5 parts of an amine compound of the structural formula
[Chemical formula 5]

And 10 parts of the polymer described in Condition 1 in Table 2 were dissolved in a mixed solvent of 30 parts of monochlorobenzene and 70 parts of dichloromethane.
[0065]
This polymer was prepared by dissolving a predetermined biphenol (0.01 mol), sodium hydroxide (0.8 g) and tetramethylammonium chloride (1 g) in 100 ml of water and putting it in a 1 liter mixer, and 1,2-dichloroethane was added thereto. A solution of terephthalic acid chloride (0.005 mol) and isophthalic acid chloride (0.005 mol) in (30 ml) was added with stirring, stirred at high speed for 10 minutes, allowed to stand for 2 hours, and 1,2-dichloroethane liquid was added. A large amount of hexane was added to this and recovered as a polymer. In addition, what was fully dried after the collection | recovery process by water washing | cleaning after collection | recovery, chloroform dissolution, and methanol dripping was used.
[0066]
The recovered polymer was measured for water content by the Karl Fischer method. The water content of the polymer described in Condition 1 in Table 2 was 1.8 mgH ₂ O / 1 g.
[0067]
This paint was applied by a dip coating method and dried at 120 ° C. for 2 hours to form a 25 μm charge transport layer.
[0068]
Next, evaluation will be described.
[0069]
The apparatus was attached to a modified laser beam printer “Laser Shot A404” manufactured by Canon and subjected to continuous durability of 5000 sheets at 32 ° C. and 95% RH. The apparatus was set so that the charging potential Vd of the dark part when not irradiated was −650 V, and the potential Vl when irradiated with laser light was −170 V.
[0070]
The evaluation is performed by measuring the dark portion charging potential Vd before and after the endurance, the potential Vl at the time of laser light irradiation, and the residual potential Vsl after the pre-exposure, and at the same time outputting a solid white image before the endurance. Was classified into 5 ranks of 1 (minor) to 5 (occurrence of many). The results are shown in Table 3.
[0071]
[Table 4]

The mixing ratio of terephthalic acid chloride and isophthalic acid chloride was 1: 1 by molar ratio.
[Examples 2 to 12]
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the binder resin for the charge transporting layer used in the conditions 2 to 12 in Table 2 was used. The results are shown in Table 3.
[0072]
[Table 5]

[Comparative Examples 1-5]
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the binder resin for the charge transporting layer used in the conditions 1 to 5 in Table 4 was used. The results are shown in Table 5.
[0073]
[Table 6]

[0074]
[Table 7]

[0075]
【The invention's effect】
The electrophotographic photoreceptor of the present invention has excellent solvent crack resistance without impairing mechanical strength, and is effective in improving electric resistance against discharge due to direct charging. Therefore, it is possible to provide an electrophotographic photosensitive member that is easy to manufacture with small characteristics and suitable for direct charging, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus having a process cartridge having an electrophotographic photosensitive member of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electrophotographic photosensitive member 2 Axis 3 Primary charging means 4 Image exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Image fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Rail

Claims (3)

In the electrophotographic photosensitive member having a photosensitive layer on a conductive support, the surface layer of the electrophotographic photosensitive member has a repeating unit represented by the following general formula (1) having a water content of 2.5 mgH ₂ O / 1 g or less. An electrophotographic photosensitive member, which is a coating film of a paint obtained by dissolving a polyarylate resin having an organic solvent in an organic solvent :

Wherein X is —CR ₁₃ R ₁₄ — (R ₁₃ and R ₁₄ are each a hydrogen atom, an alkyl group or an aryl group which may be substituted, or a divalent alkylidene group extending over R ₁₃ and R ₁₄ ), Each of which may be substituted is an alkylene group or a fluorene group, a single bond, —O—, —S—, —SO—, or —SO ₂ —, wherein R _{1 to} R ₁₂ are hydrogen atoms, halogen atoms, substituted Each of which may be an alkyl group or an aryl group) .   The electrophotographic photosensitive member according to claim 1 and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means are integrally supported, and are detachable from the main body of the electrophotographic apparatus. Process cartridge.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an image exposing unit, a developing unit, and a transferring unit.

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