JP2004163862A - Electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic apparatus which is free of occurrence of an abnormal image and keeps producing stable high-resolution images even when repeatedly used at high speed. <P>SOLUTION: The electrophotographic apparatus is provided with an electrifying means, an exposure means, a developing means, a transfer means and an electrophotographic photoreceptor. A transfer electric current applied from the transfer means to the photoreceptor is ≥65 μA. The electrophotographic photoreceptor is obtained by sequentially stacking a charge generating layer and a charge transport layer on a conductive support. The charge generating layer contains titanyl phthalocyanine crystals having the highest diffraction peak at 27.2° as a diffraction peak (±0.2°) at a Bragg angle 2θ for a CuKα ray (whose wavelength is 1.542 Å), further having main peaks at 9.4°, 9.6° and 24.0°, having a peak at 7.3° as a diffraction peak on the smallest angle side, and having no peak between the above peaks at 7.3° and 9.4°. <P>COPYRIGHT: (C)2004,JPO

Description

式中、Ｒ_１，Ｒ_２，Ｒ_３はそれぞれ独立して置換もしくは無置換のアルキル基またはハロゲン原子、Ｒ_４は水素原子または置換もしくは無置換のアルキル基、Ｒ_５，Ｒ_６は置換もしくは無置換のアリール基、ｏ，ｐ，ｑはそれぞれ独立して０〜４の整数、ｋ，ｊは組成を表わし、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表わし５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、または下記一般式で表わされる２価基を表わす。
【００８４】
【化２】

式中、Ｒ_１０１，Ｒ_１０２は各々独立して置換もしくは無置換のアルキル基、アリール基またはハロゲン原子を表わす。ｌ、ｍは０〜４の整数、Ｙは単結合、炭素原子数１〜１２の直鎖状、分岐状もしくは環状のアルキレン基、−Ｏ−，−Ｓ−，−ＳＯ−，−ＳＯ_２−，−ＣＯ−，−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（式中Ｚは脂肪族の２価基を表わす。）または、
【００８５】
【化３】

（式中、ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ_１０３、Ｒ_１０４は置換または無置換のアルキル基またはアリール基を表わす。）を表わす。ここで、Ｒ_１０１とＲ_１０２，Ｒ_１０３とＲ_１０４は、それぞれ同一でも異なってもよい。
【００８６】
【化４】

式中、Ｒ_７，Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１，Ａｒ_２，Ａｒ_３は同一あるいは異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００８７】
【化５】

式中、Ｒ_９，Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４，Ａｒ_５，Ａｒ_６は同一あるいは異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００８８】
【化６】

式中、Ｒ_１１，Ｒ_１２は置換もしくは無置換のアリール基、Ａｒ_７，Ａｒ₈，Ａｒ₉は同一あるいは異なるアリレン基、ｐは１〜５の整数を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００８９】
【化７】

式中、Ｒ_１３，Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０，Ａｒ_１１，Ａｒ_１２は同一あるいは異なるアリレン基、Ｘ_１，Ｘ_２は置換もしくは無置換のエチレン基、または置換もしくは無置換のビニレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００９０】
【化８】

式中、Ｒ_１５，Ｒ_１６，Ｒ_１７，Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３，Ａｒ_１４，Ａｒ_１５，Ａｒ_１６は同一あるいは異なるアリレン基、Ｙ_１，Ｙ_２，Ｙ_３は単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わし同一であっても異なってもよい。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００９１】
【化９】

式中、Ｒ_１９，Ｒ_２０は水素原子、置換もしくは無置換のアリール基を表わし、Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７，Ａｒ_１８，Ａｒ_１９は同一あるいは異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００９２】
【化１０】

式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０，Ａｒ_２１，Ａｒ_２２，Ａｒ_２３は同一あるいは異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００９３】
【化１１】

式中、Ｒ_２２，Ｒ_２３，Ｒ_２４，Ｒ_２５は置換もしくは無置換のアリール基、Ａｒ_２４，Ａｒ_２５，Ａｒ_２６，Ａｒ_２７，Ａｒ_２８は同一あるいはまたは異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００９４】
【化１２】

式中、Ｒ_２６，Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９，Ａｒ_３０，Ａｒ_３１は同一あるいは異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（Ｉ）の場合と同じである。
【００９５】
また、電荷輸送層に使用される高分子電荷輸送物質として、上述の高分子電荷輸送物質の他に、電荷輸送層の成膜時には電子供与性基を有するモノマーあるいはオリゴマーの状態で、成膜後に硬化反応あるいは架橋反応をさせることで、最終的に２次元あるいは３次元の架橋構造を有する重合体も含むものである。
【００９６】
これら電子供与性基を有する重合体から構成される電荷輸送層、あるいは架橋構造を有する重合体は耐摩耗性に優れたものである。通常、電子写真プロセスにおいては、帯電電位（未露光部電位）は一定であるため、繰り返し使用により感光体の表面層が摩耗すると、その分だけ感光体にかかる電界強度が高くなってしまう。この電界強度の上昇に伴い、地汚れの発生頻度が高くなるため、感光体の耐摩耗性が高いことは、地汚れに対して有利である。これら電子供与性基を有する重合体から構成される電荷輸送層は、自身が高分子化合物であるため成膜性に優れ、低分子分散型高分子からなる電荷輸送層に比べ、電荷輸送部位を高密度に構成することが可能で電荷輸送能に優れたものである。このため、高分子電荷輸送物質を用いた電荷輸送層を有する感光体には高速応答性が期待できる。
【００９７】
その他の電子供与性基を有する重合体としては、公知単量体の共重合体や、ブロック重合体、グラフト重合体、スターポリマーや、また、例えば特開平３−１０９４０６号公報、特開２０００−２０６７２３号公報、特開２００１−３４００１号公報等に開示されているような電子供与性基を有する架橋重合体などを用いることも可能である。
【００９８】
本発明において電荷輸送層（３７）中に可塑剤やレベリング剤を添加してもよい。可塑剤としては、ジブチルフタレート、ジオクチルフタレートなど一般の樹脂の可塑剤として使用されているものがそのまま使用でき、その使用量は、結着樹脂に対して０〜３０重量％程度が適当である。レベリング剤としては、ジメチルシリコーンオイル、メチルフェニルシリコーンオイルなどのシリコーンオイル類や、側鎖にパーフルオロアルキル基を有するポリマーあるいは、オリゴマーが使用され、その使用量は結着樹脂に対して、０〜１重量％が適当である。
【００９９】
本発明の電子写真感光体には、導電性支持体（３１）と感光層との間に中間層を設けることができる。中間層は一般には樹脂を主成分とするが、これらの樹脂はその上に感光層を溶媒で塗布することを考えると、一般の有機溶剤に対して耐溶剤性の高い樹脂であることが望ましい。このような樹脂としては、ポリビニルアルコール、カゼイン、ポリアクリル酸ナトリウム等の水溶性樹脂、共重合ナイロン、メトキシメチル化ナイロン等のアルコール可溶性樹脂、ポリウレタン、メラミン樹脂、フェノール樹脂、アルキッド−メラミン樹脂、エポキシ樹脂等、三次元網目構造を形成する硬化型樹脂等が挙げられる。また、中間層にはモアレ防止、残留電位の低減等のために酸化チタン、シリカ、アルミナ、酸化ジルコニウム、酸化スズ、酸化インジウム等で例示できる金属酸化物の微粉末顔料を加えてもよい。
【０１００】
これらの中間層は前述の感光層の如く適当な溶媒、塗工法を用いて形成することができる。更に本発明の中間層として、シランカップリング剤、チタンカップリング剤、クロムカップリング剤等を使用することもできる。この他、本発明の中間層には、Ａｌ_２Ｏ_３を陽極酸化にて設けたものや、ポリパラキシリレン（パリレン）等の有機物やＳｉＯ_２、ＳｎＯ_２、ＴｉＯ_２、ＩＴＯ、ＣｅＯ_２等の無機物を真空薄膜作成法にて設けたものも良好に使用できる。このほかにも公知のものを用いることができる。中間層の膜厚は０〜５μｍが適当である。
【０１０１】
本発明の電子写真感光体には、感光層保護の目的で、保護層が感光層の上に設けられることもある。近年、日常的にコンピュータの使用が行なわれるようになり、プリンタによる高速出力とともに、装置の小型も望まれている。したがって、保護層を設け、耐久性を向上させることによって、本発明の高感度で異常欠陥のない感光体を有用に用いることができる。
【０１０２】
本発明の感光体においては、感光層保護の目的で、保護層（３９）が感光層の上に設けられることもある。保護層（３９）に使用される材料としてはＡＢＳ樹脂、ＡＣＳ樹脂、オレフィン−ビニルモノマー共重合体、塩素化ポリエーテル、アリル樹脂、フェノール樹脂、ポリアセタール、ポリアミド、ポリアミドイミド、ポリアクリレート、ポリアリルスルホン、ポリブチレン、ポリブチレンテレフタレート、ポリカーボネート、ポリアリレート、ポリエーテルスルホン、ポリエチレン、ポリエチレンテレフタレート、ポリイミド、アクリル樹脂、ポリメチルベンテン、ポリプロピレン、ポリフェニレンオキシド、ポリスルホン、ポリスチレン、ＡＳ樹脂、ブタジエン−スチレン共重合体、ポリウレタン、ポリ塩化ビニル、ポリ塩化ビニリデン、エポキシ樹脂等の樹脂が挙げられる。中でも、ポリカーボネートもしくはポリアリレートが最も良好に使用できる。
【０１０３】
保護層にはその他、耐摩耗性を向上する目的でポリテトラフルオロエチレンのような弗素樹脂、シリコーン樹脂、及びこれらの樹脂に酸化チタン、酸化錫、チタン酸カリウム、シリカ等の無機フィラー、また有機フィラーを分散したもの等を添加することができる。
また、感光体の保護層に用いられるフィラー材料のうち有機性フィラー材料としては、ポリテトラフルオロエチレンのようなフッ素樹脂粉末、シリコーン樹脂粉末、ａ−カーボン粉末等が挙げられ、無機性フィラー材料としては、銅、スズ、アルミニウム、インジウムなどの金属粉末、シリカ、酸化錫、酸化亜鉛、酸化チタン、酸化インジウム、酸化アンチモン、酸化ビスマス、アンチモンをドープした酸化錫、錫をドープした酸化インジウム等の金属酸化物、チタン酸カリウムなどの無機材料が挙げられる。特に、フィラーの硬度の点からは、この中でも無機材料を用いることが有利である。特に、シリカ、酸化チタン、アルミナが有効に使用できる。
【０１０４】
保護層中のフィラー濃度は使用するフィラー種により、また感光体を使用する電子写真プロセス条件によっても異なるが、保護層の最表層側において全固形分に対するフィラーの比で５重量％以上、好ましくは１０重量％以上、５０重量％以下、好ましくは３０重量％以下程度が良好である。
また、使用するフィラーの体積平均粒径は、０．１μｍ〜２μｍの範囲が良好に使用され、好ましくは０．３μｍ〜１μｍの範囲である。この場合、平均粒径が小さすぎると耐摩耗性が充分に発揮されず、大きすぎると塗膜の表面性が悪くなったり、塗膜そのものが形成できなかったりするからである。
【０１０５】
なお、本発明におけるフィラーの平均粒径とは、特別な記載のない限り体積平均粒径であり、超遠心式自動粒度分布測定装置：ＣＡＰＡ−７００（堀場製作所製）により求めたものである。この際、累積分布の５０％に相当する粒子径（Ｍｅｄｉａｎ系）として算出されたものである。また、同時に測定される各々の粒子の標準偏差が１μｍ以下であることが重要である。これ以上の標準偏差の値である場合には、粒度分布が広すぎて、本発明の効果が顕著に得られなくなってしまう場合がある。
また、本発明で使用するフィラーのｐＨも解像度やフィラーの分散性に大きく影響する。その理由の一つとしては、フィラー、特に金属酸化物は製造時に塩酸等が残存することが考えられる。その残存量が多い場合には、画像ボケの発生は避けられず、またそれは残存量によってはフィラーの分散性にも影響を及ぼす場合がある。
【０１０６】
もう一つの理由としては、フィラー、特に金属酸化物の表面における帯電性の違いによるものである。通常、液体中に分散している粒子はプラスあるいはマイナスに帯電しており、それを電気的に中性に保とうとして反対の電荷を持つイオンが集まり、そこで電気二重層が形成されることによって粒子の分散状態は安定化している。粒子から遠ざかるに従いその電位（ゼータ電位）は徐々に低くなり、粒子から充分に離れて電気的に中性である領域の電位はゼロとなる。したがって、ゼータ電位の絶対値の増加によって粒子の反発力が高くなることによって安定性は高くなり、ゼロに近づくに従い凝集しやすく不安定になる。一方、系のｐＨ値によってゼータ電位は大きく変動し、あるｐＨ値において電位はゼロとなり等電点を持つことになる。したがって、系の等電点からできるだけ遠ざけて、ゼータ電位の絶対値を高めることによって分散系の安定化が図られることになる。
【０１０７】
本発明の構成においては、フィラーとしては前述の等電点におけるｐＨが、少なくとも５以上を示すものが画像ボケ抑制の点から好ましく、より塩基性を示すフィラーであるほどその効果が高くなる傾向があることが確認された。等電点におけるｐＨが高い塩基性を示すフィラーは、系が酸性であったほうがゼータ電位はより高くなることにより、分散性及びその安定性は向上することになる。
ここで、本発明におけるフィラーのｐＨは、ゼータ電位から等電点におけるｐＨ値を記載した。この際、ゼータ電位の測定は、大塚電子（株）製レーザーゼータ電位計にて測定した。
【０１０８】
更に、画像ボケが発生しにくいフィラーとしては、電気絶縁性が高いフィラー（比抵抗が１０^１０Ω・ｃｍ以上）が好ましく、フィラーのｐＨが５以上を示すものやフィラーの誘電率が５以上を示すものが特に有効に使用できる。また、ｐＨが５以上のフィラーあるいは誘電率が５以上のフィラーを単独で使用することはもちろん、ｐＨが５以下のフィラーとｐＨが５以上のフィラーとを２種類以上を混合したり、誘電率が５以下のフィラーと誘電率が５以上のフィラーとを２種類以上混合したりして用いることも可能である。また、これらのフィラーの中でも高い絶縁性を有し、熱安定性が高い上に、耐摩耗性が高い六方細密構造であるα型アルミナは、画像ボケの抑制や耐摩耗性の向上の点から特に有用である。
【０１０９】
本発明において使用するフィラーの比抵抗は以下のように定義される。フィラーのような粉体は、充填率によりその比抵抗値が異なるので、一定の条件下で測定する必要がある。本発明においては、特開平５−９４０４９号公報（図１）、特開平５−１１３６８８号公報（図１）に示された測定装置と同様の構成の装置を用いて、フィラーの比抵抗値を測定し、この値を用いた。測定装置において、電極面積は４．０ｃｍ２である。測定前に片側の電極に４ｋｇの荷重を１分間かけ、電極間距離が４ｍｍになるように試料量を調節する。測定の際は、上部電極の重量（１ｋｇ）の荷重状態で測定を行ない、印加電圧は１００Ｖにて測定する。１０６Ω・ｃｍ以上の領域は、ＨＩＧＨ ＲＥＳＩＳＴＡＮＣＥ ＭＥＴＥＲ（横河ヒューレットパッカード）、それ以下の領域についてはデジタルマルチメーター（フルーク）により測定した。これにより得られた比抵抗値を本発明でいうところの比抵抗値と定義するものである。
【０１１０】
フィラーの誘電率は以下のように測定した。上述のような比抵抗の測定と同様なセルを用い、荷重をかけた後に、静電容量を測定し、これより誘電率を求めた。静電容量の測定は、誘電体損測定器（安藤電気）を使用した。
【０１１１】
更に、これらのフィラーは少なくとも一種の表面処理剤で表面処理させることが可能であり、そうすることがフィラーの分散性の面から好ましい。フィラーの分散性の低下は残留電位の上昇だけでなく、塗膜の透明性の低下や塗膜欠陥の発生、さらには耐摩耗性の低下をも引き起こすため、高耐久化あるいは高画質化を妨げる大きな問題に発展する可能性がある。表面処理剤としては、従来用いられている表面処理剤すべてを使用することができるが、フィラーの絶縁性を維持できる表面処理剤が好ましい。例えば、チタネート系カップリング剤、アルミニウム系カップリング剤、ジルコアルミネート系カップリング剤、高級脂肪酸等、あるいはこれらとシランカップリング剤との混合処理や、Ａｌ_２Ｏ_３、ＴｉＯ_２、ＺｒＯ_２、シリコーン、ステアリン酸アルミニウム等、あるいはそれらの混合処理がフィラーの分散性及び画像ボケの点からより好ましい。シランカップリング剤による処理は、画像ボケの影響が強くなるが、上記の表面処理剤とシランカップリング剤との混合処理を施すことによりその影響を抑制できる場合がある。表面処理量については、用いるフィラーの平均一次粒径によって異なるが、３〜３０ｗｔ％が適しており、５〜２０ｗｔ％がより好ましい。表面処理量がこれよりも少ないとフィラーの分散効果が得られず、また多すぎると残留電位の著しい上昇を引き起こす。これらフィラ−材料は単独もしくは２種類以上混合して用いられる。フィラーの表面処理量に関しては、上述のようにフィラー量に対する使用する表面処理剤の重量比で定義される。
【０１１２】
これらフィラー材料は、適当な分散機を用いることにより分散できる。また、保護層の透過率の点から使用するフィラーは１次粒子レベルまで分散され、凝集体が少ないほうが好ましい。
【０１１３】
また、保護層（３９）には残留電位低減、応答性改良のため、電荷輸送物質を含有しても良い。電荷輸送物質は、電荷輸送層の説明のところに記載した材料を用いることができる。電荷輸送物質として、低分子電荷輸送物質を用いる場合には、保護層中における濃度傾斜を設けても構わない。耐摩耗性向上のため、表面側を低濃度にすることは有効な手段である。ここでいう濃度とは、保護層を構成する全材料の総重量に対する低分子電荷輸送物質の重量の比を表わし、濃度傾斜とは上記重量比において表面側において濃度が低くなるような傾斜を設けることを示す。また、高分子電荷輸送物質を用いることは、感光体の耐久性を高める点で非常に有利である。
【０１１４】
保護層の形成法としては通常の塗布法が採用される。なお保護層の厚さは０．１〜１０μｍ程度が適当である。また、以上のほかに真空薄膜作成法にて形成したａ−Ｃ、ａ−ＳｉＣなど公知の材料を保護層として用いることができる。
【０１１５】
上述したように、感光層（電荷輸送層）に高分子電荷輸送物質を使用したり、あるいは感光体の表面に保護層を設けることは、各々の感光体の耐久性（耐摩耗性）を高めるだけでなく、後述のようなタンデム型フルカラー画像形成装置中で使用される場合には、モノクロ画像形成装置にはない新たな効果をも生み出すものである。
【０１１６】
フルカラーの画像の場合、様々な形態の画像が入力されるが、逆に定型的な画像も入力される場合がある。例えば、日本語の文書等における検印の存在などである。検印のようなものは通常、画像領域の端のほうに位置され、また使用される色も限定される。ランダムな画像が常に書き込まれているような状態においては、画像形成要素中の感光体には、平均的に画像書き込み、現像、転写が行なわれることになるが、上述のように特定の部分に数多くの画像形成が繰り返されたり、特定の画像形成要素ばかり使用された場合には、その耐久性のバランスを欠くことにつながる。このような状態で表面の耐久性（物理的・化学的・機械的）の小さな感光体が使用された場合には、この差が顕著になり、画像上の問題になりやすい。一方、感光体を高耐久化した場合には、このような局所的な変化量が小さく、結果的に画像上の欠陥として現われにくくなるため、高耐久化を実現すると共に、出力画像の安定性をも増すことになり、非常に有効である。
【０１１７】
【実施例】
以下、本発明を実施例を挙げて説明するが、本発明が実施例により制約を受けるものではない。なお、部はすべて重量部である。
まず、本発明に用いた電荷発生材料の合成例について述べる。
（合成例１）
１，３−ジイミノイソインドリン２９．２ｇとスルホラン２００ｍｌを混合し、窒素気流下でチタニウムテトラブトキシド２０．４ｇを滴下する。滴下終了後、徐々に１８０℃まで昇温し、反応温度を１７０℃〜１８０℃の間に保ちながら５時間撹拌して反応を行なった。反応終了後、放冷した後析出物を濾過し、クロロホルムで粉体が青色になるまで洗浄し、つぎにメタノールで数回洗浄し、さらに８０℃の熱水で数回洗浄した後乾燥し、粗チタニルフタロシアニンを得た。粗チタニルフタロシアニンを２０倍量の濃硫酸に溶解し、１００倍量の氷水に撹拌しながら滴下し、析出した結晶をろ過、ついで洗浄液が中性になるまで水洗いを繰り返し、チタニルフタロシアニン顔料のウェットケーキ（水ペースト）を得た。得られたこのウェットケーキ（水ペースト）２ｇをテトラヒドロフラン２０ｇに投入し、４時間攪拌を行なった。これにメタノール１００ｇを追加して、１時間攪拌を行なった後、濾過を行ない、乾燥して、本発明のチタニルフタロシアニン粉末を得た。
得られたチタニルフタロシアニン粉末を、下記の条件によりＸ線回折スペクトル測定したところ、Ｃｕ−Ｋα線（波長１．５４２Å）に対するブラッグ角２θが２７．２±０．２°に最大ピークと最低角７．３±０．２°にピークを有し、かつ７．４〜９．４°の範囲にピークを有さないチタニルフタロシアニン粉末を得られた。その結果を図７に示す。
また、合成例１で得られた水ペーストの一部を８０℃の減圧下（５ｍｍＨｇ）で、２日間乾燥して、低結晶性チタニルフタロシアニン粉末を得た。水ペーストの乾燥粉末のＸ線回折スペクトルを図１３に示す。
【０１１８】
（Ｘ線回折スペクトル測定条件）
Ｘ線管球：Ｃｕ
電圧：５０ｋＶ
電流：３０ｍＡ
走査速度：２°／分
走査範囲：３°〜４０°
時定数：２秒
【０１１９】
（合成例２）
特開平１−２９９８７４号（特許第２５１２０８１号）公報、実施例１に記載の方法に準じて、顔料を作製した。すなわち、先の合成例１で作製したウェットケーキを乾燥し、乾燥物１ｇをポリエチレングリコール５０ｇに加え、１００ｇのガラスビーズと共に、サンドミルを行なった。結晶転移後、希硫酸、水酸化アンモニウム水溶液で順次洗浄し、乾燥して顔料を得た。
【０１２０】
（合成例３）
特開平３−２６９０６４号（特許第２５８４６８２号）公報、製造例１に記載の方法に準じて、顔料を作製した。すなわち、先の合成例１で作製したウェットケーキを乾燥し、乾燥物１ｇをイオン交換水１０ｇとモノクロルベンゼン１ｇの混合溶媒中で１時間撹拌（５０℃）した後、メタノールとイオン交換水で洗浄し、乾燥して顔料を得た。
【０１２１】
（合成例４）
特開平２−８２５６号（特公平７−９１４８６号）公報の製造例に記載の方法に準じて、顔料を作製した。すなわち、フタロジニトリル９．８ｇと１−クロロナフタレン７５ｍｌを撹拌混合し、窒素気流下で四塩化チタン２．２ｍｌを滴下する。滴下終了後、徐々に２００℃まで昇温し、反応温度を２００℃〜２２０℃の間に保ちながら３時間撹拌して反応を行なった。反応終了後、放冷し１３０℃になったところ熱時ろ過し、次いで１−クロロナフタレンで粉体が青色になるまで洗浄、次にメタノールで数回洗浄し、さらに８０℃の熱水で数回洗浄した後、乾燥し顔料を得た。
【０１２２】
（合成例５）
特開昭６４−１７０６６号（特公平７−９７２２１号）公報、合成例１に記載の方法に準じて、顔料を作製した。すなわち、α型ＴｉＯＰｃ５部を食塩１０ｇおよびアセトフェノン５ｇと共にサンドグラインダーにて１００℃にて１０時間結晶変換処理を行なった。これをイオン交換水及びメタノールで洗浄し、希硫酸水溶液で精製し、イオン交換水で酸分がなくなるまで洗浄した後、乾燥して顔料を得た。
【０１２３】
（合成例６）
特開平１１−５９１９号（特許第３００３６６４号）公報、実施例１に記載の方法に準じて、顔料を作製した。すなわち、Ｏ−フタロジニトリル２０．４部、四塩化チタン部７．６部をキノリン５０部中で２００℃にて２時間加熱反応後、水蒸気蒸留で溶媒を除き、２％塩化水溶液、続いて２％水酸化ナトリウム水溶液で精製し、メタノール、Ｎ，Ｎ−ジメチルホルムアミドで洗浄後、乾燥し、チタニルフタロシアニンを得た。このチタニルフタロシアニン２部を５℃の９８％硫酸４０部の中に少しずつ溶解し、その混合物を約１時間、５℃以下の温度を保ちながら攪拌する。続いて硫酸溶液を高速攪拌した４００部の氷水中に、ゆっくりと注入し、析出した結晶を濾過する。結晶を酸が残量しなくなるまで蒸留水で洗浄し、ウエットケーキを得る。そのケーキをＴＨＦ１００部中で約５時間攪拌を行ない、ろ過、ＴＨＦによる洗浄を行ない乾燥後、顔料を得た。
【０１２４】
（合成例７）
特開平３−２５５４５６号（特許第３００５０５２号）公報、合成例２に記載の方法に準じて、顔料を作製した。すなわち、左記の合成例１で作製したウェットケーキ１０部を塩化ナトリウム１５部とジエチレングリコール７部に混合し、８０℃の加熱下で自動乳鉢により６０時間ミリング処理を行なった。次に、この処理品に含まれる塩化ナトリウムとジエチレングリコールを完全に除去するために充分な水洗を行なった。これを減圧乾燥した後にシクロヘキサノン２００部と直径１ｍｍのガラスビーズを加えて、３０分間サンドミルにより処理を行ない、顔料を得た。
【０１２５】
（合成例８）
合成例１の方法に従って、チタニルフタロシアニン顔料の水ペーストを合成し、次のように結晶変換を行ない、合成例１よりも一次粒子の小さなフタロシアニン結晶を得た。
合成例１で得られた結晶変換前の水ペースト６０部にテトラヒドロフラン１５００部を加え、室温下でホモミキサー（ケニス、ＭＡＲＫIIｆモデル）により強烈に撹拌（２０００ｒｐｍ）し、ペーストの濃紺色の色が淡い青色に変化したら（撹拌開始後２０分）、撹拌を停止し、直ちに減圧濾過を行なった。濾過装置上で得られた結晶をテトラヒドロフランで洗浄し、顔料のウェットケーキを得た。これを減圧下（５ｍｍＨｇ）、７０℃で２日間乾燥して、チタニルフタロシアニン結晶５８部を得た。
【０１２６】
合成例１で作製された結晶変換前チタニルフタロシアニン（水ペースト）の一部をイオン交換水でおよそ１重量％になるように希釈し、表面を導電性処理した銅製のネットですくい取り、チタニルフタロシアニンの粒子サイズを透過型電子顕微鏡（ＴＥＭ、日立：Ｈ−９０００ＮＡＲ）にて、７５０００倍の倍率で観察を行なった。平均粒子サイズとして、以下のように求めた。
【０１２７】
上述のように観察されたＴＥＭ像をＴＥＭ写真として撮影し、映し出されたチタニルフタロシアニン粒子（針状に近い形）を３０個任意に選び出し、それぞれの長径の大きさを測定する。測定した３０個体の長径の算術平均を求めて、平均粒子サイズとした。
以上の方法により求められた合成例１における水ペースト中の平均粒子サイズは、０．０６μｍであった。
【０１２８】
また、合成例１及び８における濾過直前の結晶変換後チタニルフタロシアニン結晶を、テトラヒドロフランでおよそ１重量％になるように希釈し、上の方法と同様に観察を行なった。上記のようにして求めた平均粒子サイズを表１に示す。なお、合成例１及び８で作製されたチタニルフタロシアニン結晶は、必ずしも全ての結晶の形が同一ではなかった（三角形に近い形、四角形に近い形など）。このため、結晶の最も大きな対角線の長さを長径として、計算を行なった。
【０１２９】
【表１】

【０１３０】
以上の合成例２〜７で作製した顔料は、先程と同様の方法でＸ線回折スペクトルを測定し、それぞれの公報に記載のスペクトルと同様であることを確認した。また、合成例８で作成した顔料のＸ線回折スペクトルは、合成例１で作製した顔料のスペクトルと一致した。表２にそれぞれのＸ線回折スペクトルと合成例１で得られた顔料のＸ線回折スペクトルのピーク位置の特徴を示す。
【０１３１】
【表２】

【０１３２】
（感光体作製例１）
直径６０ｍｍのアルミニウムシリンダー（ＪＩＳ１０５０）に、下記組成の下引き層塗工液、電荷発生層塗工液、および電荷輸送層塗工液を、順次塗布・乾燥し、３．５μｍの下引き層、電荷発生層、２５μｍの電荷輸送層を形成し、積層感光体を作製した（感光体１とする）。なお、電荷発生層の膜厚は、７８０ｎｍにおける電荷発生層の透過率が２０％になるように調整した。電荷発生層の透過率は、下記組成の電荷発生層塗工液を、ポリエチレンテレフタレートフィルムを巻き付けたアルミシリンダーに感光体作製と同じ条件で塗工を行ない、比較対照を電荷発生層を塗工していないポリエチレンテレフタレートフィルムとし、市販の分光光度計（島津：ＵＶ−３１００）にて、７８０ｎｍの透過率を評価した。
◎下引き層塗工液
酸化チタン（ＣＲ−ＥＬ：石原産業社製） ７０部
アルキッド樹脂 １５部
（ベッコライトＭ６４０１−５０−Ｓ（固形分５０％）、大日本インキ化学工業製）
メラミン樹脂 １０部
（スーパーベッカミンＬ−１２１−６０（固形分６０％）、大日本インキ化学工業製）
２−ブタノン １００部
◎電荷発生層塗工液
下記組成の分散液を下に示す条件のビーズミリングにより作製した。
合成例１で作製したチタニルフタロシアニン顔料 １５部
ポリビニルブチラール（積水化学製：ＢＸ−１） １０部
２−ブタノン ２８０部
市販のビーズミル分散機に直径０．５ｍｍのＰＳＺボールを用い、ポリビニルブチラールを溶解した２−ブタノンおよび顔料を全て投入し、ローター回転数１５００ｒ．ｐ．ｍ．にて３０分間分散を行ない、分散液を作製した。
この分散液中の顔料粒子の粒度分布を、堀場製作所：ＣＡＰＡ−７００にて測定した。その結果、平均粒径０．２９μｍ、標準偏差０．１８μｍであった。
◎電荷輸送層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１３３】
【化１３】

塩化メチレン ８０部
【０１３４】
（感光体作製例２〜８）
感光体作製例１で使用した電荷発生層塗工液に用いたチタニルフタロシアニン顔料（合成例１で作製）をそれぞれ、合成例２〜８で作製したチタニルフタロシアニン顔料に変更した以外は、感光体作製例１と同様に感光体を作製した。なお、電荷発生層の膜厚は、感光体作製例１と同様に、すべての塗工液を用いた場合に７８０ｎｍの透過率が２０％になるように調整した。
【０１３５】
（感光体作製例９）
感光体作製例１で使用した電荷発生層塗工液を、塗工前にアドバンテック社製、コットンワインドカートリッジフィルター、ＴＣＷ−３−ＣＳ（有効孔径３μｍ）を用いて、濾過を行なった。濾過に際しては、ポンプを使用し、加圧状態で濾過を行なった。
【０１３６】
（感光体作製例１０）
感光体作製例１で使用した電荷発生層塗工液を、塗工前にアドバンテック社製、コットンワインドカートリッジフィルター、ＴＣＷ−１−ＣＳ（有効孔径１μｍ）を用いて、濾過を行なった。濾過に際しては、ポンプを使用し、加圧状態で濾過を行なった。
【０１３７】
（感光体作製例１１）
感光体作製例１で使用した電荷発生層塗工液を、塗工前にアドバンテック社製、コットンワインドカートリッジフィルター、ＴＣＷ−５−ＣＳ（有効孔径５μｍ）を用いて、濾過を行なった。濾過に際しては、ポンプを使用し、加圧状態で濾過を行なった。
【０１３８】
（実施例１〜５および比較例１〜１７）
以上のように作製した感光体作製例１〜１１の電子写真感光体を図１に示す電子写真装置に搭載し、画像露光光源を７８０ｎｍの半導体レーザー（ポリゴン・ミラーによる画像書き込み）、帯電部材として接触方式の帯電ローラ、転写部材として転写ベルトを用い、下記の帯電、転写条件にて、書き込み率６％のチャートを用い、連続２０万枚印刷後の画像を評価し、文字抜け、地汚れの有無を確認した（試験環境は、２２℃−５５％ＲＨである）。この際、図１２に示すような回路にて、転写電流の制御を行なった。なお、評価は４段階にて行ない、極めて良好なものを◎、良好なものを○、やや劣るものを△、非常に悪いものを×で表わした。以上の結果を表３に示す。
【０１３９】
帯電条件：
ＤＣバイアス：−９００Ｖ
ＡＣバイアス：２．０ｋＶ（Peak to peak）、周波数：１．５ｋＨｚ
転写条件：
７５μＡ、６０μＡの２条件
【０１４０】
【表３】

【０１４１】
（感光体作製例１２）
感光体作製例１における電荷輸送層塗工液を以下の組成のものに変更した以外は、感光体作製例１と同様に感光体を作製した。
◎電荷輸送層塗工液
下記組成の高分子電荷輸送物質 １０部
（重量平均分子量：約１３５０００）
【０１４２】
【化１４】

下記構造の添加剤 ０．５部
【０１４３】
【化１５】

塩化メチレン １００部
【０１４４】
（感光体作製例１３）
感光体作製例１における電荷輸送層の膜厚を２０μｍとし、電荷輸送層上に下記組成の保護層塗工液を塗布乾燥し、５μｍの保護層を設けた以外は感光体作製例１と同様に感光体を作製した。
◎保護層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１４５】
【化１６】

アルミナ微粒子 ４部
（比抵抗：２．５×１０^１２Ω・ｃｍ、平均一次粒径：０．４μｍ）
シクロヘキサノン ５００部
テトラヒドロフラン １５０部
【０１４６】
（感光体作製例１４）
感光体作製例１３における保護層塗工液中のアルミナ微粒子を以下のものに変更した以外は、感光体作製例１３と同様に感光体を作製した。
酸化チタン微粒子 ４部
（比抵抗：１．５×１０^１０Ω・ｃｍ、平均一次粒径：０．５μｍ）
【０１４７】
（感光体作製例１５）
感光体作製例１３における保護層塗工液中のアルミナ微粒子を以下のものに変更した以外は、感光体作製例１３と同様に感光体を作製した。
酸化錫−酸化アンチモン粉末 ４部
（比抵抗：１０^６Ω・ｃｍ、平均１次粒径０．４μｍ）
【０１４８】
（感光体作製例１６）
感光体作製例１におけるアルミニウムシリンダー（ＪＩＳ１０５０）を以下の陽極酸化皮膜処理を行ない、次いで下引き層を設けずに、感光体作製例１と同様に電荷発生層、電荷輸送層を設け、感光体を作製した。
◎陽極酸化皮膜処理
支持体表面の鏡面研磨仕上げを行ない、脱脂洗浄、水洗浄を行なった後、液温２０℃、硫酸１５ｖｏｌ％の電解浴に浸し、電解電圧１５Ｖにて３０分間陽極酸化皮膜処理を行なった。更に、水洗浄を行なった後、７％の酢酸ニッケル水溶液（５０℃）にて封孔処理を行なった。その後純水による洗浄を経て、７μｍの陽極酸化皮膜が形成された支持体を得た。
【０１４９】
（実施例６〜１４および比較例１８〜２３）
以上のように作製した感光体作製例１〜１６の電子写真感光体を図１に示す電子写真装置に搭載し、画像露光光源を７８０ｎｍの半導体レーザー（ポリゴン・ミラーによる画像書き込み）として、帯電部材として帯電部材として図２に示すような帯電ローラの両端部に厚さ５０μｍの絶縁テープを巻き付けた近接配置用の帯電部材（感光体と帯電部材表面間の空隙が５０μｍ）を用い、下記の帯電、転写条件にて、書き込み率６％のチャートを用い、連続２０万枚印刷後の地汚れの有無、及びハーフトーン画像を確認した（試験環境は、２２℃−５５％ＲＨである）。この際、図１２に示すような回路にて、転写電流の制御を行なった。なお、地汚れの評価は４段階にて行ない、極めて良好なものを◎、良好なものを○、やや劣るものを△、非常に悪いものを×で表わした。また、２０万枚印刷後の感光層の摩耗量（保護層を有する場合は保護層の摩耗量）を測定した。以上の結果を表４に示す。
【０１５０】
帯電条件：
ＤＣバイアス：−９００Ｖ
ＡＣバイアス：２．０ｋＶ（Peak to peak）、周波数：１．５ｋＨｚ
転写条件：
９０μＡ
【０１５１】
【表４】

【０１５２】
（実施例１６）
実施例６において２０万枚の通紙試験の後、３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
【０１５３】
（実施例１７）
実施例６における帯電部材を近接配置用帯電部材からスコロトロン・チャージャーに変更し、感光体非画像部の表面電位を実施例６と同じ（−９００Ｖ）にあわせるようにセッティングした。これ以外の条件を変更せずに、実施例６と同様に２０万枚の通紙試験を行なった。通紙試験の後、実施例１５と同様に３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
【０１５４】
（実施例１８）
実施例６における帯電部材を近接配置用帯電部材から接触用帯電部材（空隙なし）に変更し、帯電条件を実施例６と同じ条件にセッティングした。これ以外の条件を変更せずに、実施例６と同様に２０万枚の通紙試験を行なった。通紙試験の後、実施例１６と同様に３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
【０１５５】
（実施例１９）
実施例１８における帯電条件を以下のように変更した以外は、実施例１８と同様に評価を行なった。
帯電条件：
ＤＣバイアス：−１６００Ｖ（初期状態の感光体非画像部の表面電位が−９００Ｖ）
ＡＣバイアス：なし
【０１５６】
（実施例２０）
実施例６における帯電条件を以下のように変更した以外は、実施例６と同様に評価を行なった。２０万枚の通紙試験の後、実施例１６と同様に３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
帯電条件：
ＤＣバイアス：−１６００Ｖ（初期状態の感光体非画像部の表面電位が−９００Ｖ）
ＡＣバイアス：なし
【０１５７】
（実施例２１）
実施例６で使用した帯電部材（近接帯電ローラ）のギャップを１００μｍに変更した以外は、実施例６と同様に評価を行なった。２０万枚の通紙試験の後、実施例１６と同様に３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
【０１５８】
（実施例２２）
実施例６で使用した帯電部材（近接帯電ローラ）のギャップを１５０μｍに変更した以外は、実施例６と同様に評価を行なった。２０万枚の通紙試験の後、実施例１６と同様に３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
【０１５９】
（実施例２３）
実施例１６で使用した帯電部材（近接帯電ローラ）のギャップを２５０μｍに変更した以外は、実施例１６と同様に評価を行なった。２０万枚の通紙試験の後、実施例１６と同様に３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
【０１６０】
（実施例２４）
実施例７において２０万枚の通紙試験の後、３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
【０１６１】
（実施例２５）
実施例８において２０万枚の通紙試験の後、３０℃−９０％ＲＨ環境下でハーフトーン画像を出力し、画像評価を行なった。
以上の実施例１６〜２５における評価結果を表５に示す。
【０１６２】
【表５】

【０１６３】
（感光体作製例１７）
感光体作製例１の電荷輸送層塗工液を以下の組成に変更した以外は、感光体作製例１と同様に感光体を作製した。
◎電荷輸送層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１６４】
【化１７】

テトラヒドロフラン ８０部
【０１６５】
（感光体作製例１８）
感光体作製例６の電荷輸送層塗工液を以下の組成に変更した以外は、感光体作製例６と同様に感光体を作製した。
◎電荷輸送層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１６６】
【化１８】

テトラヒドロフラン ８０部
【０１６７】
（感光体作製例１９）
感光体作製例１の電荷輸送層塗工液を以下の組成に変更した以外は、感光体作製例１と同様に感光体を作製した。
◎電荷輸送層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１６８】
【化１９】

ジオキソラン ８０部
【０１６９】
（感光体作製例２０）
感光体作製例１の電荷輸送層塗工液を以下の組成に変更した以外は、感光体作製例１と同様に感光体を作製した。
◎電荷輸送層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１７０】
【化２０】

テトラヒドロフラン ４０部
トルエン ４０部
【０１７１】
（感光体作製例２１）
感光体作製例８の電荷輸送層塗工液を以下の組成に変更した以外は、感光体作製例８と同様に感光体を作製した。
◎電荷輸送層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１７２】
【化２１】

テトラヒドロフラン ８０部
【０１７３】
（感光体作製例２２）
感光体作製例９の電荷輸送層塗工液を以下の組成に変更した以外は、感光体作製例９と同様に感光体を作製した。
◎電荷輸送層塗工液
ポリカーボネート（ＴＳ２０５０：帝人化成社製） １０部
下記構造式の電荷輸送物質 ７部
【０１７４】
【化２２】

テトラヒドロフラン ８０部
【０１７５】
（実施例２６〜３０および比較例２４）
以上のように作製した感光体作製例１７〜２２の感光体を実施例１の場合と同様に、図１に示す電子写真装置に搭載し、画像露光光源を７８０ｎｍの半導体レーザー（ポリゴン・ミラーによる画像書き込み）として、帯電部材として接触方式の帯電ローラを用い、下記の帯電、転写条件にて、ハーフトーンライン画像を出力した。この際、図１２に示すような回路にて、転写電流の制御を行なった。以上の結果を実施例１および比較例５と併せて表６に示す。
【０１７６】
帯電条件：
ＤＣバイアス：−９００Ｖ
ＡＣバイアス：２．０ｋＶ（Ｐｅａｋ ｔｏ ｐｅａｋ）、周波数：１．５ｋＨｚ
転写条件：
１１０μＡ
【０１７７】
【表６】

【０１７８】
（感光体作製例２３）
感光体作製例１のアルミシリンダーを直径３０ｍｍのものに変え、感光体作製例１と同じ組成の感光体を作製した。
【０１７９】
（感光体作製例２４）
感光体作製例４のアルミシリンダーを直径３０ｍｍのものに変え、感光体作製例４と同じ組成の感光体を作製した。
【０１８０】
（感光体作製例２５）
感光体作製例５のアルミシリンダーを直径３０ｍｍのものに変え、感光体作製例５と同じ組成の感光体を作製した。
【０１８１】
（感光体作製例２６）
感光体作製例８のアルミシリンダーを直径３０ｍｍのものに変え、感光体作製例８と同じ組成の感光体を作製した。
【０１８２】
（感光体作製例２７）
感光体作製例９のアルミシリンダーを直径３０ｍｍのものに変え、感光体作製例９と同じ組成の感光体を作製した。
【０１８３】
（実施例３１〜３３および比較例２５〜３１）
以上のように作製した感光体作製例２３〜２７の感光体を、帯電部材と共に１つの電子写真装置用プロセスカートリッジに装着し、更に図４に示すフルカラー電子写真装置に搭載した。４つの画像形成要素は以下に示すプロセス条件にてフルカラー画像２０万枚通紙試験の後に文字抜け、地汚れの有無の確認、及びハーフトーン画像評価を実施した（試験環境は、２２℃−５５％ＲＨである）。この際、図１２に示すような回路にて、転写電流の制御を行なった。なお、文字抜け、地汚れ評価は４段階にて行ない、極めて良好なものを◎、良好なものを○、やや劣るものを△、非常に悪いものを×で表わした。以上の結果を表７に示す。
【０１８４】
帯電条件：ＤＣバイアス −８００Ｖ、
ＡＣバイアス １．５ｋＶ（ｐｅａｋ ｔｏ ｐｅａｋ）、
周波数 ２．０ｋＨｚ
帯電部材：実施例２に使用したものと同じ
書き込み：７８０ｎｍのＬＤ（ポリゴン・ミラー使用）
転写条件：７５μＡ、６０μＡの２条件
【０１８５】
【表７】

【０１８６】
最後に、本発明で使用するチタニルフタロシアニン結晶の特徴であるブラッグ角θの最低角ピークである７．３°について、公知材料の最低角７．５°と同一であるか否かについて検証する。
【０１８７】
（合成例９）
合成例１における結晶変換溶媒を塩化メチレンから２−ブタノンに変更した以外は、合成例１と同様に処理を行ない、チタニルフタロシアニン結晶を得た。
合成例１の場合と同様に、合成例９で作製したチタニルフタロシアニン結晶のＸＤスペクトルを測定した。これを図８に示す。図８より、合成例９で作製されたチタニルフタロシアニン結晶のＸＤスペクトルにおける最低角は、合成例１で作製されたチタニルフタロシアニンの最低角（７．３°）とは異なり、７．５°に存在することが判る。
【０１８８】
（測定例１）
合成例１で得られた顔料（最低角７．３°）に特開昭６１−２３９２４８号公報に記載の顔料（最大回折ピークを７．５°に有する）と同様に作製したものを３重量％添加し、乳鉢で混合して、先程と同様にＸ線回折スペクトルを測定した。測定例１のＸ線回折スペクトルを図９に示す。
【０１８９】
（測定例２）
合成例９で得られた顔料（最低角７．５°）に特開昭６１−２３９２４８号公報に記載の顔料（最大回折ピークを７．５°に有する）と同様に作製したものを３重量％添加し、乳鉢で混合して、先程と同様にＸ線回折スペクトルを測定した。測定例２のＸ線回折スペクトルを図１０に示す。
【０１９０】
図９のスペクトルにおいては、低角側に７．３°と７．５°の２つの独立したピークが存在し、少なくとも７．３°と７．５°のピークは異なるものであることが判る。一方、図１０のスペクトルにおいては、低角側のピークは７．５°のみに存在し、図９のスペクトルとは明らかに異なっている。
以上のことから、本願発明のチタニルフタロシアニン結晶における最低角ピークである７．３°は、公知のチタニルフタロシアニン結晶における７．５°のピークとは異なるものであることが判る。
【０１９１】
【発明の効果】
以上、詳細かつ具体的な発明から明らかなように、本発明によれば、高速で繰り返し使用した際に、異常画像の発生がなく、安定で解像度の高い画像を出力する電子写真装置が提供される。
具体的には、転写手段における逆帯電による感光体の電気的劣化を解消し、安定で解像度の高い画像を出力する電子写真装置が提供される。また、電荷輸送層用塗工液に非ハロゲン系溶媒を用いた場合においても、チタニルフタロシアニン固有の高感度を維持した電子写真装置が提供される。
【図面の簡単な説明】
【図１】本発明の電子写真プロセスおよび電子写真装置を説明するための概略図である。
【図２】本発明において、帯電部材側にギャップ形成部材を配置した近接帯電機構の一例を示した図である。
【図３】本発明の電子写真装置用プロセスカートリッジを説明するための図である。
【図４】本発明のタンデム方式のフルカラー電子写真装置を説明するための概略図である。
【図５】本発明に用いられる電子写真感光体の層構成を表わした図である。
【図６】本発明に用いられる別の電子写真感光体の層構成を表わした図である。
【図７】合成例１で合成されたチタニルフタロシアニンのＸＤスペクトルを表わした図である。
【図８】合成例９で合成されたチタニルフタロシアニンのＸＤスペクトルを表わした図である。
【図９】測定例１で用いたチタニルフタロシアニンのＸＤスペクトルを表わした図である。
【図１０】測定例２で用いたチタニルフタロシアニンのＸＤスペクトルを表わした図である。
【図１１】転写電流と転写効率の関係を表わした図である。
【図１２】定電流制御可能な転写回路例を表わした図である。
【図１３】水ペーストの乾燥粉末のＸＤスペクトルを表わした図である。
【図１４】分散時間が短い場合の分散液の状態を示す図である。
【図１５】分散時間が長い場合の分散液の状態を示す図である。
【図１６】図１４、１５の分散液について、平均粒径及び粒度分布を示す図である。
【図１７】不定形チタニルフタロシアニンのＴＥＭ像である。図中のスケール・バーは、０．２μｍである。
【図１８】結晶変換後のチタニルフタロシアニンのＴＥＭ像である。図中のスケール・バーは、０．２μｍである。
【図１９】短時間で結晶変換を行なったチタニルフタロシアニン結晶のＴＥＭ像である。図中のスケール・バーは、０．２μｍである。
【符号の説明】
１ 感光体
１Ｃ 感光体
１Ｍ 感光体
１Ｙ 感光体
１Ｋ 感光体
２ 除電ランプ
２Ｃ 帯電部材
２Ｍ 帯電部材
２Ｙ 帯電部材
２Ｋ 帯電部材
３ 帯電ローラ
３Ｃ レーザー光
３Ｍ レーザー光
３Ｙ レーザー光
３Ｋ レーザー光
４Ｃ 現像部材
４Ｍ 現像部材
４Ｙ 現像部材
４Ｋ 現像部材
５ 画像露光部
５Ｃ クリーニング部材
５Ｍ クリーニング部材
５Ｙ クリーニング部材
５Ｋ クリーニング部材
６ 現像ユニット
６Ｃ 画像形成要素
６Ｍ 画像形成要素
６Ｙ 画像形成要素
６Ｋ 画像形成要素
７ 転写紙
８ 給紙コロ
９ レジストローラ
１０ 転写搬送ベルト
１１ 転写バイアスローラ
１１Ｃ 転写ブラシ
１１Ｍ 転写ブラシ
１１Ｙ 転写ブラシ
１１Ｋ 転写ブラシ
１２ 定着装置
１３ クリーニング前チャージャー
１４ ファーブラシ
１５ クリーニングブラシ
１６ 現像ローラ
１７ 転写ローラ
１８ 分離爪
２１ ギャップ形成部材
２２ 金属シャフト
２３ 画像形成領域
２４ 非画像形成領域
３１ 導電性支持体
３３ 中間層
３５ 電荷発生層
３７ 電荷輸送層
１００ 感光体
１０１ 転写ベルト
１０２ 駆動ローラ
１０３ 従動ローラ
１０４ バイアスローラ
１０５ 高圧電源（パワーパック）
１０６ 電流検出抵抗[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic apparatus using an electrophotographic photosensitive member in which transfer is performed by applying a specific current or more and a charge generation layer and a charge transport layer containing at least a specific titanyl phthalocyanine crystal are sequentially laminated.
[0002]
[Prior art]
2. Description of the Related Art In recent years, the development of information processing system machines using an electrophotographic system has been remarkable. In particular, an optical printer that converts information into a digital signal and records information by light has remarkably improved in print quality and reliability. This digital recording technology is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, a copier equipped with the digital recording technology in a conventional analog copy is expected to have a further increasing demand in the future because various information processing functions are added. Further, with the spread of personal computers and improvement in performance, the progress of digital color printers for outputting images and documents in color has been rapidly progressing.
[0003]
In recent years, there has been a demand for smaller printers and higher speed printers and copiers. As a result, the photoreceptor also needs to be small and rotate at high speed, which shortens the time from exposure to the photoreceptor until the toner image is developed, and increases the number of rotations of the photoreceptor. As a result, problems such as accelerating the deterioration of electrical characteristics due to repeated use have arisen.
As a means for achieving this, the charge generation material has a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 27.2 ° with respect to CuKα ray (wavelength 1.542 °) which is a highly sensitive material. It is known to use a titanyl phthalocyanine crystal having a diffraction peak.
[0004]
However, this crystal type has low stability as a crystal, and has a problem that it easily undergoes crystal transition due to mechanical stress such as dispersion and thermal stress. The sensitivity is extremely low as compared with the above, and when a part of the crystal undergoes crystal transition, a sufficient photocarrier generation function cannot be exhibited. In addition, when the photoreceptor is repeatedly used, the application of reverse charging to the photoreceptor by the transfer unit based on the negative / positive development accelerates the deterioration of the charging property, and particularly, an abnormal image called a background image is easily generated. It also has points.
[0005]
In addition, since the frequency of outputting images has been greatly increased, it is also important to improve the image quality of the apparatus. To achieve this, (i) forming by means of charging means and exposure means Forming a high-density image of the electrostatic latent image on the photosensitive member to be formed, (ii) forming a toner image faithfully on the electrostatic latent image by the subsequent developing means, and (iii) finally forming the photosensitive member. There are three problems of accurately transferring the upper toner image to transfer paper.
Means for solving these problems are (i) a method of forming an electrostatic latent image by high-density writing using a small-diameter beam as an exposure means, and (ii) a reduction of toner particle diameter in a developing means. And (iii) increasing the gap electric field strength in the transfer means to increase the transfer efficiency and faithfully transfer the toner image on the photoreceptor to the transfer paper. Transfer method.
However, the increase in the gap electric field intensity due to the transfer means is caused by a titanyl phthalocyanine having a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the CuKα ray (wavelength 1.542 °). When a photoreceptor using a crystal is repeatedly used, the deterioration of electric characteristics is particularly promoted, which causes an abnormal image called background stain similarly to the above. Therefore, the advantage of high sensitivity of the titanyl phthalocyanine crystal cannot be fully utilized.
[0006]
On the other hand, the charge transport layer that performs the charge transport function is mainly composed of the charge transport material and the binder resin as described above, and is generally formed by applying a coating solution in which these materials are dissolved or dispersed in a solvent. It is a target. As the solvent, halogen-based solvents such as dichloromethane and chloroform are mainly used because they exhibit excellent properties in solubility and coatability.
[0007]
In recent years, awareness of environmental problems has increased, and development of a photoreceptor using a non-halogen solvent having a small impact on the human body and the environment has been desired. However, when a photoreceptor is manufactured using the coating solution for a charge transport layer using a non-halogen solvent, there is a problem that the light attenuation characteristic in a low electric field is reduced and the residual potential is increased. In particular, the Bragg angle 2θ with respect to a specific crystal type (CuKα ray (wavelength 1.542 °)) exhibiting a rare high sensitivity in a wavelength range (600 to 780 nm) where a relatively stable oscillation output of an LD or LED can be obtained at present. This phenomenon is remarkable in titanyl phthalocyanine having a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °), and this phenomenon is remarkable. It is not possible and it is a big issue.
[0008]
Various studies have also been made on a method using a non-halogen solvent, and for example, a method using a dioxolane compound as a solvent as a halogen-free organic solvent (for example, see Patent Document 1) has been proposed. Further, a method has been proposed in which a specific antioxidant or an ultraviolet absorber is added to a cyclic ether solvent such as tetrahydrofuran (see, for example, Patent Documents 2 and 3). However, even when these methods are used, there have been problems such as an insufficient effect on the above-mentioned defects, or a deterioration in sensitivity characteristics due to the influence of additives.
Therefore, even when a non-halogen solvent is used for the charge transport layer coating liquid, an electrophotographic photoreceptor that exhibits good light attenuation characteristics using titanyl phthalocyanine having a specific high sensitivity as a charge generating substance, It has been desired to complete the used electrophotographic apparatus and the process cartridge for electrophotography.
[0009]
[Patent Document 1]
JP-A-10-326023 (page 3, column 3, line 4 to line 25)
[Patent Document 2]
JP 2001-356506 A (page 3, column 4, line 13 to line 23)
[Patent Document 3]
JP-A-4-191745 (page 3, upper right column, third line to ninth line)
[Patent Document 4]
JP-A-7-302002
[Patent Document 5]
JP-A-10-186886
[Patent Document 6]
JP-A-2000-75572
[Patent Document 7]
JP 2001-305888 A
[0010]
[Problems to be solved by the invention]
Accordingly, it is an object of the present invention to provide an electrophotographic apparatus which does not generate an abnormal image when repeatedly used at a high speed and outputs a stable and high-resolution image.
Specifically, the present invention provides an electrophotographic apparatus that controls a transfer current in a transfer unit, eliminates the above-described problem by using a photoconductor that is resistant to electrical deterioration of the photoconductor due to reverse charging, and outputs a stable and high-resolution image. Is to do. Another object of the present invention is to provide an electrophotographic apparatus which maintains the high sensitivity inherent in titanyl phthalocyanine even when a non-halogen solvent is used in the coating solution for the charge transport layer.
[0011]
[Means to solve the problem]
The present inventors have conducted a number of studies on a high-speed digital electrophotographic apparatus to output a stable and high-resolution image without generating an abnormal image when repeatedly used at a high speed. An electrophotographic photosensitive member in which an applied current applied to the body is 65 μA or more, and wherein the electrophotographic photosensitive member is formed by sequentially laminating at least a charge generation layer and a charge transport layer on a conductive support; Among them, as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to CuKα ray (wavelength 1.542 °), it has a maximum diffraction peak at least at 27.2 °, and further 9.4 °, 9.6 °, It has a main peak at 24.0 ° and a peak at 7.3 ° as the lowest diffraction peak, and has a peak between 7.3 ° and 9.4 °. Is titanyl phthalo having no peak It has been found that the above problem can be solved by including a cyanine crystal.
Such a transfer current of 65 μA or more is larger than a general transfer current in electrophotography (see FIG. 1.37 on page 51 of FIG. 11: “Basic and Application of Electrophotographic Technology”, edited by the Society of Electrophotography, Japan). ), Particularly in high-speed digital electrophotographic apparatuses having a linear velocity of 200 mm / sec or more, particularly when used at high speed. Although the detailed reason for the effect of the present invention is unknown, our investigation results show that the maximum diffraction peak at 27.2 °, which has been known so far, is higher than that of other titanyl phthalocyanine crystals, and that the titanyl used in the present invention is higher. It is presumed to be derived from the high chemical stability of the phthalocyanine crystal.
[0012]
As for the control of the transfer current itself, constant current control is known, and is described in, for example, Patent Documents 4 to 7. In particular, in performing the constant current control, an output current from a power supply (power supply means such as a high-voltage power supply) for supplying a charge to the transfer member and a current flowing to a support for supporting the transfer belt and the like are measured, and a difference between the output current and the current is measured. Is a transfer current applied to the photoreceptor, and feedback control for controlling the difference by a monitored change in the difference is known. However, in these publications, like the fact described in the above-mentioned literature, the feedback control is applied to the photoreceptor. Current control is performed for the purpose of reducing inconvenience that occurs when the current is too large, and its upper limit is as small as at most about 50 μA. This is because, similarly to the problem described above, the application of a reverse bias during transfer causes electrostatic deterioration of the photoconductor. In this way, while effective means for controlling the process have been developed, no effective photoreceptor has been developed to take advantage of its features. At present, there remain problems such as the presence of transfer residual toner on the body and the inability to accurately transfer a toner image faithful to the electrostatic latent image on the photoreceptor. Solved.
[0013]
That is, the above object is achieved by (1) an electrophotographic apparatus including at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member, which is applied to the photosensitive member from the transferring unit. A transfer current of 65 μA or more, and an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are sequentially laminated on a conductive support, wherein a CuKα ray ( As a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to a wavelength of 1.542 °), it has a maximum diffraction peak at least at 27.2 °, and further has a peak at 9.4 °, 9.6 °, and 24.0 °. It has a main peak, a peak at 7.3 ° as the lowest diffraction peak, and a peak between the 7.3 ° peak and the 9.4 ° peak. Contains no titanyl phthalocyanine crystals (2) "Electrophotographic apparatus according to the above (1), wherein transfer current is controlled by constant current control", (3) "Electrophotographic apparatus from power supply during transfer" A current measuring means provided in a feedback mechanism for feeding back a bypass current flowing to the transfer member without flowing to the photoreceptor to a power supply, whereby a difference between an output current from the power supply and a current measured by the current measuring means is provided. (1) The electrophotographic apparatus according to the above (1) or (2), wherein the transfer current flowing to the photoreceptor is controlled, and (4) "the titanyl phthalocyanine crystal further comprises 26.3." The electrophotographic apparatus according to any one of the above items (1) to (3), which has no peak at ゜, and (5) “the titanyl phthalocyanine crystal has an average primary particle size of 0. 0.3 μm The electrophotographic apparatus according to any one of the above items (1) to (4) ", (6) wherein the volume average particle size of the titanyl phthalocyanine crystal particles is 0.3 μm or less; Dispersion is performed until the standard deviation becomes 0.2 μm or less, and thereafter, a dispersion obtained by filtering with a filter having an effective pore size of 3 μm or less is used, and a photoreceptor coated with a charge generation layer is used (5). And (7) that the titanyl phthalocyanine has a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 7.0 to CuKα characteristic X-ray (wavelength 1.542 °). Amorphous titanyl phthalocyanine or low-crystalline titanyl phthalocyanine having a maximum diffraction peak at 7.5 ° and a primary particle whose half width of the diffraction peak is 1 ° or more and an average size of 0.1 μm or less. Is subjected to crystal transformation with an organic solvent in the presence of water, and before the average size of the primary particles after the crystal transformation grows to 0.3 μm or more, the titanyl phthalocyanine after the crystal transformation is separated from the organic solvent and filtered. (8) wherein the charge transport layer contains a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain. (9) The electrophotographic apparatus according to any one of the above items (1) to (7), and (9) the electrophotographic device having a protective layer on the charge transport layer. (8) The electrophotographic apparatus according to any one of (8) and (10), wherein the protective layer has a resistivity of 10 ¹⁰ (9) The electrophotographic apparatus according to the above (9), wherein the metal oxide contains an inorganic pigment or a metal oxide of Ω · cm or more. ¹⁰ (10) The electrophotographic photosensitive member according to the above (10), wherein the metal oxide has a specific resistance of 10 or more. ¹⁰ (13) The electrophotographic photoreceptor according to the above (10), wherein the protective layer contains a polymer charge transport material. (14) The electrophotographic photoreceptor according to any one of the above items (9) to (12), (14) that the charge transport layer of the photoreceptor is formed using a non-halogen solvent. (15) The electrophotographic apparatus according to any one of (1) to (13), wherein the non-halogen solvent is at least one selected from cyclic ethers and aromatic hydrocarbons. (14) The electrophotographic apparatus according to the above (14), wherein (16) the electrophotographic photoreceptor has a conductive support surface which is anodized. According to any one of the above modes (1) to (15) (17) "(1) to (16), wherein a plurality of image forming elements comprising at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member are arranged. (18) The electrophotographic apparatus according to any one of the above (1) to (17), wherein the charging means of the electrophotographic apparatus uses a contact charging method. (19) The electronic device according to any one of (1) to (17), wherein a non-contact proximity arrangement method is used for a charging unit of the electrophotographic device. (20) “Electrophotographic apparatus according to (19), wherein the gap between the charging member used for the charging unit and the photoconductor is 200 μm or less”, (21) “ AC charging voltage is applied to the charging means of the electrophotographic device. (20) The electrophotographic apparatus according to any one of the above (18) to (20), wherein the photosensitive member and at least a charging unit, an exposing unit, a developing unit, and a cleaning unit are selected. An electrophotographic apparatus according to any one of the above items (1) to (21), further comprising a device main body integrated with one means to be mounted and a detachable cartridge. You.
[0014]
First, the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram for explaining an electrophotographic process and an electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.
In FIG. 1, a photoreceptor (1) is provided with at least a photosensitive layer including a charge generation layer and a charge transport layer on a conductive support, and the charge generation layer has a Bragg angle with respect to CuKα radiation (wavelength 1.542 °). As a 2θ diffraction peak (± 0.2 °), it has a maximum diffraction peak at least at 27.2 °, and further has major peaks at 9.4 °, 9.6 °, 24.0 °, and It contains a titanyl phthalocyanine crystal having a peak at 7.3 ° as a diffraction peak on the lowest angle side and having no peak between the peak at 7.3 ° and the peak at 9.4 °. Become. The photoconductor (1) has a drum shape, but may have a sheet shape or an endless belt shape.
Known means such as a corotron, a scorotron, and a solid state charger (solid state charger) can be used for the charging roller (3).
Although a transfer charger and a transfer roller can be used as the transfer belt (10), it is preferable to use a contact type such as a transfer belt or a transfer roller that generates a small amount of ozone. As the voltage / current application method at the time of transfer, any of a constant voltage method and a constant current method can be used. However, the transfer charge amount can be kept constant, and a constant voltage excellent in stability can be obtained. The current method is more desirable.
[0015]
Also, among the charging methods, at least a charging member (noted as a charging roller (3) in FIG. 1) used for main charging of the photoreceptor has a contact charging method or a non-contact proximity arrangement method. Is desirable. The charging member of the contact charging type or the non-contact proximity arrangement type has advantages such as high charging efficiency, small ozone generation amount, and downsizing of the device.
Here, the contact-type charging member is of a type in which the surface of the charging member comes into contact with the surface of the photoreceptor, and includes a charging roller, a charging blade, and a charging brush. Among them, a charging roller and a charging brush are preferably used.
[0016]
In addition, the charging member disposed close to the charging member is a type in which the charging member is disposed in a non-contact state so as to have a gap (gap) of 200 μm or less between the surface of the photoconductor and the surface of the charging member. If this gap is too large, charging tends to be unstable, and if it is too small, the surface of the charging member may be contaminated if toner remaining on the photoreceptor exists. . Therefore, the gap is suitably in the range of 10 to 200 μm, preferably 10 to 100 μm. From the distance of the air gap, it is distinguished from a known charging wire type charger such as a corotron and a scorotron, and a contact charging member such as a contact type charging roller, a charging brush, and a charging blade.
[0017]
Since the surface of such a charging member is placed in a state of non-contact with the surface of the photoreceptor, there is little toner contamination on the surface of the charging member, little wear on the surface of the charging member, and physical properties of the surface of the charging member. In this case, the charging member has an advantage that it has little static / chemical deterioration, and a high durability of the charging member itself can be realized. When the above-mentioned problems occur due to the use of the contact charging member and the durability of the charging member is reduced, the charging ability is reduced or the charging becomes non-uniform in repeated use in the electrophotographic apparatus. Or In order to avoid this charging failure, measures such as increasing the voltage applied to the charging member in accordance with the reduction of the charging ability are taken in repeated use. In that case, the hazard due to the charging of the photoconductor increases, and as a result, the durability of the photoconductor is reduced, and an abnormal image is generated. Further, as the voltage applied to the charging member increases, the durability of the charging member itself also decreases. However, by using a non-contact charging member, the charging capability of the charging member is stabilized due to the high durability of the charging member, thereby improving the durability and stability of the charging member, the photoreceptor, and eventually the entire system. Will be.
[0018]
The nearby charging member used in the present invention may have any shape as long as it has a mechanism capable of appropriately controlling the gap with the photoconductor surface. For example, the rotation axis of the photoreceptor and the rotation axis of the charging member may be mechanically fixed so as to have an appropriate gap. Among them, using a charging member in the shape of a charging roller, disposing gap forming members at both ends of the non-image forming portion of the charging member, bringing only this portion into contact with the surface of the photoconductor, and disposing the image forming region in a non-contact manner, Alternatively, a method in which a gap forming member at both ends of the photoreceptor non-image forming portion is arranged, and only this portion is brought into contact with the surface of the charging member, and the image forming region is arranged in a non-contact manner, stably stabilizes the gap by a simple method. It is a method that can be maintained. In particular, the methods described in JP-A-2002-148904 and JP-A-2002-148905 can be used favorably. FIG. 2 shows an example of a proximity charging mechanism in which a gap forming member is arranged on the charging member side. By using the above method, the charging efficiency is high, the amount of generated ozone is small, the size of the device can be reduced, and further, there is an advantage that contamination by toner or the like does not occur and mechanical abrasion due to contact does not occur. Used well because
[0019]
Further, as the application method, the use of AC superposition has advantages such as less occurrence of uneven charging, and can be used favorably. In particular, in a tandem-type full-color image forming apparatus to be described later, in addition to the problem of density unevenness of a halftone image due to uneven charging caused in the case of a monochrome image forming apparatus, there is a major problem of deterioration in color balance (color reproducibility). Connect. By superimposing the AC component on the DC component, the above problem is greatly improved. However, if the conditions of the AC component (frequency and peak-to-peak voltage) are too large, the hazard to the photoconductor becomes large. In some cases, the deterioration of the photoconductor is accelerated. For this reason, the superposition of the AC component should be kept to the minimum necessary.
[0020]
The frequency of the AC component varies depending on the linear speed of the photoreceptor or the like, but 3 kHz or less, preferably 2 kHz or less is appropriate. Regarding the peak-to-peak voltage, when plotting the relationship between the voltage applied to the charging member and the charging potential to the photoconductor, there is a region where the photoconductor is not charged even though the voltage is applied, and charging rises from a certain point. A potential is observed. Approximately twice the rising potential is an optimal potential (usually about 1200 to 1500 V) as a peak-to-peak voltage. However, when the charging ability of the photoreceptor is low or the linear velocity is very high, the peak-to-peak voltage twice as high as the rising potential as described above may be insufficient. Conversely, when the chargeability is good, even if the chargeability is twice or less, the potential stability may be sufficiently exhibited. Therefore, the peak-to-peak voltage is preferably three times or less, and more preferably twice or less, the rising potential. If the peak-to-peak voltage is rewritten as an absolute value, it is desirable that the voltage be used at 3 kV or less, preferably 2 kV or less, more preferably 1.5 kV or less.
[0021]
The image exposure section (5) uses a light source such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL) that can ensure high luminance. Among these light sources, light-emitting diodes and semiconductor lasers have high irradiation energy and have long wavelength light of 600 to 800 nm, so that the specific crystal type phthalocyanine pigment which is a charge generation material used in the present invention has high sensitivity. It is used well because it shows.
[0022]
The developing unit (6) can support both normal development and reversal development depending on the charging polarity of the toner used. When a toner having a polarity opposite to the charging polarity of the photoconductor is used, normal development is used. When a toner having the same polarity is used, an electrostatic latent image is developed by reversal development. Although it depends on the light source used in the above image exposure section, in the case of a digital light source used in recent years, the reversal development method of performing toner development on a writing portion generally corresponds to a low image area ratio. It is advantageous to consider the life of the light source and the like. There are two methods, a one-component method in which development is performed using only toner and a two-component method using a two-component developer composed of a toner and a carrier. In either case, the method can be used favorably.
[0023]
Further, the toner image formed on the photoconductor is transferred to a transfer sheet to form an image on the transfer sheet. At this time, there are two methods. One is a method of directly transferring a toner image developed on the surface of a photoreceptor as shown in FIG. 1 to a transfer paper, and the other is a method in which a toner image is temporarily transferred from a photoreceptor to an intermediate transfer body and is then transferred to a transfer paper. This is a method of transferring to Either case can be used in the present invention.
FIG. 1 shows a transfer belt (10) as a transfer member, but a transfer charger and a transfer roller can also be used. In particular, it is desirable to use a contact type such as a transfer belt or a transfer roller that generates a small amount of ozone. As such a transfer member, a known member can be used as long as the structure of the present invention can be satisfied.
[0024]
As the voltage / current application method at the time of transfer, any of a constant voltage method and a constant current method can be used. However, the transfer charge amount can be kept constant, and a constant voltage excellent in stability can be obtained. The current method is more desirable. In particular, by subtracting a current that flows from a power supply member (high-voltage power supply) that supplies electric charges to the transfer member to a portion related to the transfer member and does not flow into the photoconductor, the current to the photoconductor is reduced. A method of controlling the value is preferred. Specifically, in order to determine the current flowing through the rollers holding the transfer belt, the related members such as the rollers are not directly dropped to the ground, but the current flowing through the related members is returned to the high voltage power supply. It is desirable to obtain a difference from the output of the above and to perform constant current control using a high-voltage power supply having a feedback function such that the difference becomes a constant value. FIG. 12 shows an example of a circuit configuration diagram which can take such a form.
[0025]
The transfer unit of the example shown in FIG. 12 includes a transfer conveyance belt (101), a driving roller (102) and a driven roller (103) around which the transfer conveyance belt (101) is stretched, and a transfer conveyance belt (101). It has a bias roller (104) in contact with the back surface, and a cleaning device (not shown). The drive roller (102) is connected to the main motor via a gear, and the transfer conveyance belt ( 101), the transfer conveyance belt (101) is brought into contact with the photosensitive drum (100) by the belt contact / separation mechanism. Further, the transfer conveyance belt (101) is separated from the photosensitive drum (100) by turning off the main motor by a belt contact / separation mechanism.
[0026]
Further, when the transfer paper is sent from the registration roller to the transfer unit of this example, the bias roller (104) applies a transfer bias having a polarity opposite to the charge polarity of the toner to the bias roller (104) from the high voltage power supply (105). The transfer paper is applied to the nip (transfer nip) between the transfer conveyor belt (101) and the photosensitive drum (100) from the high voltage power supply (105) via the bias roller (104) and the transfer conveyor belt (101). An electric charge having a polarity opposite to the charged polarity of the toner is supplied, and the toner image on the photosensitive drum (100) is transferred.
[0027]
When a transfer bias is applied from a high-voltage power supply (105) via a bias roller (104), the transfer conveyance belt (101) electrostatically attracts the transfer paper and conveys the transfer paper as it rotates. After the transfer of the toner image, the toner image is electrostatically separated from the photosensitive drum (100). The transfer paper that has not been separated from the photoconductor drum (100) is separated from the photoconductor drum (100) by a separation claw (not shown) and is conveyed by the transfer conveyance belt (101).
The resistance range of the transfer conveyance belt (101) in this example is 1 × 10 ⁶ ~ 1 × 10 ¹² .OMEGA ./. Quadrature., And a constant good toner image transfer can always be performed irrespective of the resistance fluctuation of the transfer conveyance belt (101), the environmental fluctuation and the thickness of the transfer paper. The bias roller (104) is in contact with the transfer conveyance belt (101) downstream of the transfer nip in the rotation direction of the transfer conveyance belt (101), and rotates with the transfer conveyance belt (101) when the main motor rotates. I do.
[0028]
The feedback electrode in this example is not a metal plate or the like, but the driving roller (102) and the driven roller (103) also serve as the driving roller (102) and the driven roller (103). The sliding resistance to the belt (101) can be reduced as much as possible, and the driving roller (102) and the driven roller (103) can reliably function as a feedback electrode. In addition, since the drive roller (102) and the driven roller (103) also serve as feedback electrodes, the apparatus can be simplified and the cost can be reduced. The driving roller (102) and the driven roller (103) are connected to a low voltage side (earth side) terminal of the high voltage power supply (105). The low-voltage side terminal of the high-voltage power supply (105) is grounded via the current detection resistor (106), and the photosensitive drum (100) is grounded via the machine body. The current detection resistor (106) is used as current detection means for detecting a transfer current that contributes to the transfer of the toner image.
[0029]
FIG. 12B shows an equivalent circuit of the transfer unit. In the figure, R ₁₁ Is a resistance value between the bias roller (104) and the transfer nip portion of the transfer conveyance belt (101); ₁₂ Is a resistance value between the transfer nip portion and the driven roller (103) in the transfer conveyance belt (101); ₂ Is a resistance value between the bias roller (104) and the driving roller (102) in the transfer conveyance belt (101); _D Is the resistance value of the photosensitive drum (100), R _P Is the resistance value of the transfer paper, R _W Denotes a resistance value of the current detection resistor (106), and a resistance value R between the bias roller (104) and the driven roller (103) in the transfer conveyance belt (101). ₁ Is R ₁ = R ₁₁ + R ₁₂ It becomes.
[0030]
Also, i ₁ Is the current flowing from the high voltage power supply (105) through the bias roller (104), the transfer / transport belt (101), and the drive roller (102) ₂ Is a current flowing from the high voltage power supply (105) through the bias roller (104), the transfer / transport belt (101), and the driven roller (103); ₃ Is a current flowing from the high-voltage power supply (105) via the bias roller (104), the transfer / transport belt (101), the transfer paper, and the photosensitive drum (100).
[0031]
In the configuration of this example, the high-voltage power supply (105) is turned on at the timing when the transfer paper sent from the registration roller is conveyed by the transfer conveyance belt (101), and applies a transfer bias to the bias roller (104). At this time, the transfer bias current output from the high-voltage power supply (105) to the bias roller (104) flows through the transfer conveyance belt (101), the transfer paper, and the photosensitive drum (100), and a part thereof is transferred and transferred. It flows via a belt (101), a driving roller (102), and a driven roller (103).
[0032]
Current i flowing from the bias roller (104) to the photosensitive drum (100) via the transfer / conveyance belt (101) ₃ Is a transfer current that contributes to the transfer of the toner image and flows to ground through the machine main body. ₃ Returns to the high voltage power supply (105) through the current detection resistor (106). Further, a feedback current i flowing from the bias roller (104) through the transfer roller (101) through the driving roller (102) and the driven roller (103). ₁ , I ₂ Returns to the high-voltage power supply (105) without passing through the current detection resistor (106), the potential difference between both ends of the current detection resistor (106) and the resistance value R of the current detection resistor (106). _W The transfer current flowing through the current detection resistor (106) can be found from FIG.
[0033]
In this embodiment, the high-voltage power supply (105) includes a transfer bias power supply that outputs a transfer bias current to the bias roller (104), and a transfer current (from the bias roller (104)) that flows from the transfer bias power supply to the current detection resistor (106). The constant current control unit controls the current (flowing current) and the feedback current flowing into the feedback electrodes (102) and (103) (a difference between the feedback currents flowing into the feedback electrodes (102) and (103)) to be a fixed set transfer current. The constant current control unit controls the output current of the transfer bias power supply with a PWM pulse, and determines the duty ratio of the PWM pulse (or the gain of the output current of the transfer bias power supply) in accordance with the voltage of the current detection resistor (106). The transfer bias current is controlled to a constant value by updating at a frequency of. For this reason, in the transfer nip portion, the transfer electric field generated by the toner layer surface potential on the photosensitive drum (100) and the surface potential on the transfer paper can be kept constant, and the resistance of the transfer conveyance belt (101) can be changed. A good toner image can be always transferred irrespective of environmental fluctuations and the thickness of the transfer paper, and a good copied image can be obtained.
[0034]
Further, in this example, the constant current control unit of the high voltage power supply (105) controls the output current of the transfer bias power supply by using a PWM pulse to change the duty ratio of the PWM pulse (or the gain of the output current of the transfer bias power supply). The frequency is updated at a predetermined frequency in accordance with the voltage of the detection resistor (106). The updated frequency (period) is 0.5 cycles / mm or less, which is equal to or higher than the lower limit of the permissible level in human visual characteristics, or 1. 5 cycles / mm or more, or every one dot line or less (less than the time for writing one dot line image) of image writing by laser light in the writing unit. For this reason, it is possible to prevent the occurrence of banding that appears on the copy image in the transfer current update cycle.
[0035]
Further, as shown, the current actually contributing to the transfer of the toner image is a transfer current i. ₃ And i ₁ , I ₂ Is a feedback current that does not contribute to the transfer of the toner image. In this example, the transfer current i ₃ Is controlled by the constant current control unit of the high voltage power supply (105), the transfer bias voltage applied from the high voltage power supply (105) to the bias roller (104) is equal to the transfer current i. ₃ Of the system through which ₁₁ , R _D , R _P , R _W ) And transfer current i ₃ Depends on Therefore, if R ₁₁ Is R ₂ Is larger than i, i does not contribute to the transfer of the toner image. ₁ And the capacity of the transfer bias power supply must be increased, which is not a very efficient system. Therefore, in this example, the distance from the bias roller (104) to the driven roller (103) is L ₁ , The distance from the bias roller (104) to the drive roller (102) is L ₂ Then R ₁ And R ₂ Is R ₁ <R ₂ L so that ₁ <L ₂ It is designed to. Therefore, the capacity of the transfer bias power supply can be reduced.
[0036]
The transfer current is a current based on the amount of charge required to peel off the toner electrostatically attached to the photosensitive member and transfer the toner to a transfer target (transfer paper or an intermediate transfer member). In order to avoid transfer defects such as residual transfer, it is sufficient to increase the transfer current.However, when negative / positive development is used, it is necessary to apply a charge of the opposite polarity to the charge polarity of the photoconductor. As a result, the electrostatic fatigue of the photoconductor becomes remarkable. Therefore, in the electrophotographic apparatus up to this point, the deterioration of the electrostatic fatigue characteristic due to the application of the reverse charging of the photoconductor is rate-limiting, and it is difficult to increase the transfer current. The present inventors have found that this problem can be solved by using a photoreceptor using a titanyl phthalocyanine crystal having a specific crystal form.
The larger the transfer current is, the more advantageous it is to apply a charge amount exceeding the electrostatic adhesion force between the photoconductor and the toner. However, when the transfer current exceeds a certain threshold, a discharge phenomenon occurs between the transfer member and the photoconductor, and the transfer current becomes fine. The result is a scattering of the developed toner image. For this reason, the upper limit is a range in which this discharge phenomenon does not occur. This threshold value varies depending on the gap (distance) between the transfer member and the photoconductor, the material constituting the both, and the like. However, by using about 200 μA or less, the discharge phenomenon can be avoided. Therefore, the upper limit of the transfer current is about 200 μA.
[0037]
For the light source such as the static elimination lamp (2), use all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL). Can be. To irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used.
[0038]
Such a light source or the like irradiates the photoreceptor with light by providing a transfer step, a charge removal step, a cleaning step, or a pre-exposure step using light irradiation in addition to the step shown in FIG.
In the case where the AC component is superimposed and used in the previous charging system, or when the residual potential of the photoconductor is small, the charge removing mechanism can be omitted. In addition, instead of an optical charge elimination, an electrostatic charge elimination mechanism (for example, a charge elimination brush to which a reverse bias is applied or grounded) can be used.
[0039]
Further, the toner developed on the photoconductor (1) by the developing unit (6) is transferred to the transfer paper (7). However, when toner remaining on the photoconductor (1) is generated, the fur brush ( 14) and the blade (15) remove it from the photoreceptor. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.
[0040]
The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, or may be incorporated in the apparatus in the form of a process cartridge. The process cartridge is one device (part) that includes a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a charge removing unit, and the like. Although there are many shapes and the like of the process cartridge, a general example is shown in FIG. The photoreceptor (1) has a photosensitive layer including at least a charge generation layer and a charge transport layer provided on a conductive support. The charge generation layer has a diffraction peak at a Bragg angle of 2θ with respect to CuKα radiation (wavelength: 1.542 °). (± 0.2 °), has a maximum diffraction peak at least at 27.2 °, further has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has the lowest angle side. Contains a titanyl phthalocyanine crystal having a peak at 7.3 ° as a diffraction peak and having no peak between the peak at 7.3 ° and the peak at 9.4 °. When this process cartridge is used in an image forming apparatus, the transfer current applied to the photoconductor from the transfer unit is 65 μA or more.
[0041]
Here, the transfer current is defined. The transfer current can be defined as a current flowing from the charging member to the photoconductor. Further, when a toner image is directly transferred to a transfer material (such as paper), it can be defined as a current flowing through the photoconductor in a state where the transfer material is at the full width of the transfer member. In the case of a system in which primary transfer is performed using an intermediate transfer member or the like, and further secondary transfer is performed on a transfer material, the current is defined as a current flowing from the intermediate transfer member to the photosensitive member.
There are several methods for this measurement, but two methods are described as examples.
One is to measure the current actually flowing to the photoconductor, and to measure the current flowing from the photoconductor to the ground. However, during the operation of the electrophotographic apparatus, the current from charging is also included, so when directly measuring the current from the photoconductor to the ground, it is necessary to perform only the operation of the transfer member and perform the measurement. There is.
Another is an indirect measurement method. The current output from the high-voltage power supply used in the transfer unit is measured, the current flowing to a transfer member other than the photoconductor (for example, a drive roller of a transfer belt) is measured, and the difference between the two is obtained and the photoconductor is transferred to the photoconductor. Is obtained indirectly. In this measurement method, a high-voltage power supply having a feedback function is used, and the rollers and the like are not grounded to the ground, but are returned to the high-voltage power supply so that the difference between the output current and the return current can be detected. It is convenient to use a simple one.
[0042]
FIG. 4 is a schematic diagram for explaining a tandem-type full-color electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.
In FIG. 4, reference numerals (1C), (1M), (1Y), and (1K) denote drum-shaped photoconductors, and photoconductor (1) has at least a charge generation layer and a charge transport layer on a conductive support. And the charge generation layer has a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to CuKα radiation (wavelength 1.542 °). 9.4 °, 9.6 °, and 24.0 °, and a peak at 7.3 ° as a diffraction peak on the lowest angle side, and 7.3 °. And a peak of 9.4 ° contain a titanyl phthalocyanine crystal having no peak. The photoconductors (1C), (1M), (1Y), and (1K) rotate in the direction of the arrow in the drawing, and around them, the charging members (2C), (2M), (2Y), (2K) ), Developing members (4C), (4M), (4Y), (4K), and cleaning members (5C), (5M), (5Y), (5K). The charging members (2C), (2M), (2Y), and (2K) are charging members constituting a charging device for uniformly charging the surface of the photoconductor. From an exposure member (not shown) from the photoconductor back side between the charging members (2C), (2M), (2Y), (2K) and the developing members (4C), (4M), (4Y), (4K). Are irradiated with laser beams (3C), (3M), (3Y), and (3K) to form electrostatic latent images on the photoconductors (1C), (1M), (1Y), and (1K). Has become. Then, four image forming elements (6C), (6M), (6Y), and (6K) centered on such photoconductors (1C), (1M), (1Y), and (1K) are transferred to a transfer material. They are juxtaposed along a transfer conveyance belt (10) as a conveyance means. The transfer conveying belt (10) includes the developing members (4C), (4M), (4Y), (4K) and the cleaning member (5C) of each image forming unit (6C), (6M), (6Y), (6K). , (5M), (5Y), and (5K) are in contact with the photoconductors (1C), (1M), (1Y), and (1K), and hit the photoconductor side of the transfer / transport belt (10). Transfer brushes (11C), (11M), (11Y), and (11K) for applying a transfer bias are arranged on the surface (back surface). Each of the image forming elements (6C), (6M), (6Y), and (6K) has a different color of the toner inside the developing device, and all the other components have the same configuration.
[0043]
In the color electrophotographic apparatus having the configuration shown in FIG. 4, the image forming operation is performed as follows. First, in each of the image forming elements (6C), (6M), (6Y), and (6K), the photoconductors (1C), (1M), (1Y), and (1K) move in the direction of the arrow (the direction along which the photoconductor is rotated). ), Which is charged by the charging members (2C), (2M), (2Y), and (2K), and then exposed to laser beams (3C), (3M) at an exposure section (not shown) arranged inside the photoconductor. ), (3Y), and (3K), an electrostatic latent image corresponding to each color image to be created is formed. Next, the latent images are developed by the developing members (4C), (4M), (4Y), and (4K) to form toner images. Developing members (4C), (4M), (4Y), and (4K) are developing members for developing with C (cyan), M (magenta), Y (yellow), and K (black) toners, respectively. The toner images of the respective colors formed on the photoconductors (1C), (1M), (1Y), and (1K) are superimposed on transfer paper. The transfer paper (7) is sent out of the tray by a paper feed roller (8), temporarily stopped by a pair of registration rollers (9), and is transferred to a transfer conveyance belt (10) at the same time as the image formation on the photoconductor. Sent. The transfer paper (7) held on the transfer / conveyance belt (10) is conveyed, and each color is transferred at a contact position (transfer portion) with each of the photoconductors (1C), (1M), (1Y), and (1K). The transfer of the toner image is performed. The toner image on the photoreceptor is formed by the transfer bias applied to the transfer brushes (11C), (11M), (11Y), (11K) and the photoreceptors (1C), (1M), (1Y), (1K). Is transferred onto the transfer paper (7) by the electric field formed from the potential difference of Then, the recording paper (7) on which the four color toner images are superposed through the four transfer units is conveyed to a fixing device (12), where the toner is fixed, and is discharged to a discharge unit (not shown). Further, residual toner remaining on each of the photoconductors (1C), (1M), (1Y), and (1K) without being transferred by the transfer unit is removed by cleaning devices (5C), (5M), (5Y), and (5Y). 5K). In the example of FIG. 5, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper transport direction. However, the order is not limited to this order, and the color order is arbitrarily set. When a black-only document is created, providing a mechanism for stopping the image forming elements other than black ((6C), (6M), (6Y)) can be particularly effectively used in the present invention. . Further, in FIG. 4, the charging member is in contact with the photoreceptor, but by using a charging mechanism as shown in FIG. 2, an appropriate gap (about 10-200 μm) is provided between the two. In addition, the amount of abrasion of both can be reduced, and toner filming on the charging member is small, so that it can be used favorably.
[0044]
The image forming means as described above may be fixedly incorporated in a copying machine, a facsimile, or a printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. The process cartridge is one device (part) that includes a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a charge removing unit, and the like.
[0045]
Hereinafter, the electrophotographic photosensitive member used in the present invention will be described in detail.
The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having at least a charge generation layer and a charge transport layer formed on a conductive support, wherein the charge generation layer contains CuKα radiation (wavelength 1.542 °). Has a maximum diffraction peak at least at 27.2 ° and a major peak at 9.4 °, 9.6 ° and 24.0 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ. And a titanyl phthalocyanine crystal having a peak at 7.3 ° as a diffraction peak on the lowest angle side and having no peak between the peak at 7.3 ° and the peak at 9.4 °. It contains.
This crystal form is described in JP-A-2001-19871, but by using this titanyl phthalocyanine crystal, a stable charge that does not cause a decrease in chargeability even when repeatedly used without losing high sensitivity. An electrophotographic photosensitive member can be obtained.
Japanese Patent Application Laid-Open No. 2001-19871 discloses a charge generating substance used in the present invention, a photoreceptor using the same, and an electrophotographic apparatus. However, in a situation where the resolution is used at a resolution of 600 dpi or more or 1200 dpi or more, unless the transfer current is optimized (increased than usual), the above-described resolution degradation due to the transfer failure is caused. Was. Such a phenomenon is remarkably exhibited when used in an image forming apparatus that is faster than the image forming apparatus described in the publication. As described above, in the past processes (apparatuses), not only the ability of the materials described in the publication is not fully exploited, but also adverse effects are produced unless the process conditions are optimized.
[0046]
As a method for synthesizing a titanyl phthalocyanine crystal, a method not using a titanium halide as a raw material is preferably used, as described in JP-A-6-29369. The greatest advantage of this method is that the synthesized titanyl phthalocyanine crystal is halogen-free. When a titanyl phthalocyanine crystal contains a halogenated titanyl phthalocyanine crystal as an impurity, the electrostatic characteristics of a photoreceptor using the same often have adverse effects such as a decrease in photosensitivity and a decrease in chargeability. Shu p.103 1989). The present invention is also directed mainly to halogenated free titanyl phthalocyanine crystals as described in JP-A-2001-19871, and these materials are effectively used.
[0047]
First, a method for synthesizing a titanyl phthalocyanine crystal having a specific crystal type used in the present invention will be described.
First, a method for synthesizing a crude product of titanyl phthalocyanine crystal will be described.
Methods for synthesizing phthalocyanines have been known for a long time, and are described in Moser et al., "Phthalocyanine Compounds" (1963), "The Phthalocyanines" (1983), and JP-A-6-29369.
[0048]
For example, as a first method, there is a method in which a mixture of phthalic anhydride, a metal or a metal halide and urea is heated in the presence or absence of a high boiling point solvent. In this case, a catalyst such as ammonium molybdate is used as needed. A second method is a method in which phthalonitriles and a metal halide are heated in the presence or absence of a high boiling point solvent. This method is used for phthalocyanines that cannot be produced by the first method, for example, aluminum phthalocyanines, indium phthalocyanines, oxovanadium phthalocyanines, oxotitanium phthalocyanines, zirconium phthalocyanines, and the like. A third method is to first react ammonia with phthalic anhydride or phthalonitriles to produce an intermediate such as 1,3-diiminoisoindoline, and then react with a metal halide in a high boiling solvent. It is a way to make it. The fourth method is a method in which a phthalonitrile is reacted with a metal alkoxide in the presence of urea or the like. In particular, the fourth method does not cause chlorination (halogenation) to a benzene ring, and is a very useful method for synthesizing an electrophotographic material.
[0049]
Next, a method for synthesizing amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) will be described. In this method, a phthalocyanine is dissolved in sulfuric acid, then diluted with water and reprecipitated, and a method called an acid paste method or an acid slurry method can be used.
As a specific method, the above synthesized crude product is dissolved in 10 to 50 times the volume of concentrated sulfuric acid, and if necessary, insolubles are removed by filtration or the like, and this is sufficiently cooled to 10 to 50 times the volume of sulfuric acid. Slowly put into water or ice water to reprecipitate titanyl phthalocyanine. After filtration of the precipitated titanyl phthalocyanine, washing and filtration are performed with ion-exchanged water, and this operation is sufficiently repeated until the filtrate becomes neutral. Finally, after washing with clean ion-exchanged water, filtration is performed to obtain a water paste having a solid concentration of about 5 to 15% by weight. The product thus prepared is amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) used in the present invention. At this time, this amorphous titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) has a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 7.0 to 7 with respect to the characteristic X-ray of CuKα (wavelength 1.542 °). It preferably has a maximum diffraction peak at 0.5 °. In particular, the half width of the diffraction peak is more preferably 1 ° or more. Further, the average particle size of the primary particles is preferably 0.1 μm or less.
[0050]
Next, a crystal conversion method will be described.
The crystal transformation is performed by converting the amorphous titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) into a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 27.2 ° with respect to the characteristic X-ray of CuKα (wavelength 1.542 °). Has a maximum diffraction peak at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as a diffraction peak on the lowest angle side, In addition, this is a step of converting into a titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 ° and having no peak at 26.3 °.
As a specific method, the amorphous form of titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) is not dried, but is mixed and stirred with an organic solvent in the presence of water to obtain the crystal form. .
[0051]
At this time, as the organic solvent used, any organic solvent can be used as long as a desired crystal form can be obtained, and in particular, tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, 1,1,1 Good results are obtained when one selected from 2-trichloroethane is selected. These organic solvents are preferably used alone, but it is also possible to use a mixture of two or more of these organic solvents or a mixture with another solvent.
The above crystal conversion method is a crystal conversion method according to JP-A-2001-19871. The effect of the charge generating substance contained in the photoreceptor used in the electrophotographic apparatus of the present invention becomes more remarkable by reducing the particle size of the titanyl phthalocyanine crystal.
[0052]
In order to make the particle size of the titanyl phthalocyanine crystal finer, the present inventors have observed that the above-mentioned amorphous titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) has a primary particle size of 0.1 μm or less (the Most are about 0.01 to 0.05 μm) (see FIG. 17), but it was found that the crystal was converted along with the crystal growth during the crystal conversion. Usually, in this type of crystal conversion, a sufficient crystal conversion time is secured due to fear of remaining raw materials, and after the crystal conversion is performed sufficiently, filtration is performed, and titanyl phthalocyanine crystal having a desired crystal form is obtained. Is what you get. For this reason, despite the fact that a raw material having sufficiently small primary particles is used as the raw material, a crystal having a large primary particle (generally 0.3 to 0.5 μm) is obtained as a crystal after the crystal conversion. (See FIG. 18).
[0053]
In dispersing the titanyl phthalocyanine crystal thus produced, in order to make the particle size after dispersion small (approximately 0.2 μm or less), dispersion is performed by giving a strong shear, and further, if necessary. Dispersion is performed by giving strong energy to crush primary particles. As a result, as described above, some of the particles are transformed into a crystal form other than the desired crystal form.
[0054]
On the other hand, in the present invention, the range in which crystal growth hardly occurs during the crystal conversion (the size of the amorphous titanyl phthalocyanine particles observed in FIG. In this case, a titanyl phthalocyanine crystal having a primary particle size as small as possible is obtained by determining the point in time when the crystal conversion is completed. The particle size after the crystal conversion increases in proportion to the crystal conversion time. Therefore, as described above, it is important to increase the efficiency of crystal conversion and complete the conversion in a short time. There are several important points for this.
[0055]
One is to select an appropriate crystal conversion solvent as described above to increase the crystal conversion efficiency. The other is to use strong stirring to sufficiently contact the solvent and the aqueous paste of titanyl phthalocyanine (the raw material prepared as described above) in order to complete the crystal transformation in a short time. More specifically, a method of using a propeller having a very strong stirring power, or using an intense stirring (dispersion) means such as a homogenizer (homomixer) to realize crystal conversion in a short time. is there. Under these conditions, it is possible to obtain a titanyl phthalocyanine crystal in which the crystal conversion is sufficiently performed and no crystal growth occurs without leaving any raw material.
[0056]
Further, as described above, since the crystal grain size and the crystal conversion time are in a proportional relationship, a method of immediately stopping the reaction when a predetermined reaction (crystal conversion) is completed is also an effective means. As described above, a large amount of a solvent that is unlikely to undergo crystal conversion immediately after the crystal conversion as described above is added. Examples of the solvent that does not easily undergo crystal transformation include alcohol-based and ester-based solvents. Crystal conversion can be stopped by adding these solvents about 10 times to the crystal conversion solvent.
[0057]
The smaller the primary particle size produced in this way is, the better the result for the problem of the photoreceptor is. However, the next step (pigment filtration step) related to pigment production, the dispersion in the dispersion liquid, Considering stability, side effects may occur even if they are too small. That is, when the primary particles are very fine, there is a problem that the filtration time is very long in the step of filtering the primary particles. On the other hand, if the primary particles are too fine, the surface area of the pigment particles in the dispersion becomes large, and the possibility of reaggregation of the particles increases. Therefore, a suitable pigment particle size is in the range of about 0.05 μm to about 0.2 μm.
[0058]
FIG. 19 shows a TEM image of the titanyl phthalocyanine crystal when the crystal conversion is performed in a short time. Unlike the case of FIG. 18, the particle size is small and almost uniform, and no coarse particles as observed in FIG. 18 are observed at all.
[0059]
In dispersing the titanyl phthalocyanine crystal thus produced, a strong share is required in order to reduce the particle size after dispersion (less than 0.3 μm, preferably 0.25 μm or less, more preferably 0.2 μm or less). To disperse, and if necessary, a strong energy for pulverizing the primary particles is applied to perform dispersion. As a result, as described above, a result that a part of the particles easily transitions to a crystal form other than a desired crystal form is produced.
The particle size as referred to herein is a volume average particle size, which is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). In this case, the particle diameter was calculated as a particle diameter (Median type) corresponding to 50% of the cumulative distribution. However, since this method may not be able to detect minute amounts of coarse particles, it is important to determine the size by observing the titanyl phthalocyanine crystal powder or dispersion directly with an electron microscope to determine the size in more detail. It is.
[0060]
The above phenomenon was understood as follows as a result of examining the minute defects by further observation of the dispersion. Usually, in a method such as measuring the average particle size, when extremely large particles are present at several percent or more, the presence can be detected. When the amount becomes very small, the measurement falls below the detection limit. As a result, the measurement of the average particle size alone does not detect the presence of coarse particles, making it difficult to interpret the above minute defects.
[0061]
FIGS. 14 and 15 show photographs of the state of two kinds of dispersion liquids in which only the dispersion time was changed while the dispersion conditions were fixed. FIG. 14 shows a photograph of the dispersion liquid having a short dispersion time under the same conditions. Compared with FIG. 15 having a long dispersion time, it is observed that coarse particles remain. The black particles in FIG. 14 are coarse particles.
The average particle size and the particle size distribution of these two dispersions were measured by a commercially available particle size distribution analyzer (Horiba Seisakusho: ultracentrifugal automatic particle size analyzer, CAPA700) according to known methods. FIG. 16 shows the result. "A" in FIG. 16 corresponds to the dispersion shown in FIG. 14, and "B" corresponds to the dispersion shown in FIG. When comparing the two, there is hardly any difference in the particle size distribution. In addition, the average particle size of the two was determined to be 0.29 μm for “A” and 0.28 μm for “B”, and no difference was observed between the two after taking measurement errors into account.
Therefore, it can be understood that only the definition of the known average particle size (particle size) cannot detect residual small amounts of coarse particles and cannot cope with recent high-resolution negative-positive development. The presence of the minute amount of coarse particles was first recognized by observing the coating solution at a microscope level.
[0062]
In view of such a fact, it is effective means to produce the primary particles produced at the time of crystal conversion as small as possible. To this end, an appropriate solvent for the crystal conversion is selected as described above, and the solvent and titanyl phthalocyanine aqueous paste (the raw material prepared as described above) are used to enhance the crystal conversion efficiency and complete the crystal conversion in a short time. The method of using strong agitation in order to bring the) into sufficient contact is effective. More specifically, a method of using a propeller having a very strong stirring power, or using an intense stirring (dispersion) means such as a homogenizer (homomixer) to realize crystal conversion in a short time. is there. Under these conditions, it is possible to obtain a titanyl phthalocyanine crystal in which the crystal conversion is sufficiently performed and no crystal growth occurs without leaving any raw material.
[0063]
Further, as described above, since the crystal grain size and the crystal conversion time are in a proportional relationship, a method of immediately stopping the reaction when a predetermined reaction (crystal conversion) is completed is also an effective means. As described above, a large amount of a solvent that is unlikely to undergo crystal conversion immediately after the crystal conversion as described above is added. Examples of the solvent that does not easily undergo crystal transformation include alcohol-based and ester-based solvents. Crystal conversion can be stopped by adding these solvents about 10 times to the crystal conversion solvent.
By employing such a crystal conversion method, a titanyl phthalocyanine crystal having a small primary particle size (less than 0.3 μm, preferably 0.25 μm or less, more preferably 0.2 μm or less) can be obtained. In addition to the technique described in Japanese Patent Application Laid-Open No. 2001-19871, the use of the technique described above (a crystal conversion method for obtaining a fine titanyl phthalocyanine crystal), if necessary, can reduce the effects of the present invention. It is an effective means to increase.
[0064]
Subsequently, the crystal-converted titanyl phthalocyanine crystal is immediately filtered to be separated from the crystal conversion solvent. This filtration is performed by using a filter having an appropriate size. At this time, it is most appropriate to use vacuum filtration.
Thereafter, the separated titanyl phthalocyanine crystals are heated and dried as necessary. Any known dryer can be used for the heating and drying. However, when the drying is performed in the atmosphere, a blow dryer is preferable. Further, drying under reduced pressure is also a very effective means for increasing the drying speed and more remarkably exhibiting the effects of the present invention. In particular, it is an effective means for a material that decomposes at a high temperature or changes its crystal form. In particular, it is effective to dry in a state where the degree of vacuum is higher than 10 mmHg.
[0065]
The thus obtained titanyl phthalocyanine crystal having a specific crystal form is extremely useful as a charge generating substance for an electrophotographic photosensitive member. However, as described above, the crystal form is unstable and has a disadvantage that the crystal form is easily transferred when a dispersion is prepared. However, by synthesizing the primary particles into an extremely small one as in the present invention, a dispersion having a small average particle diameter can be produced without giving an excessive share at the time of producing the dispersion, and the crystal form is extremely small. It can be manufactured stably (without changing the synthesized crystal form).
[0066]
A general method is used for preparing the dispersion, and the titanyl phthalocyanine crystal is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, a bead mill, ultrasonic waves, or the like. It is obtained. At this time, the binder resin may be selected according to the electrostatic characteristics of the photoreceptor, and the solvent may be selected according to the wettability to the pigment, the dispersibility of the pigment, and the like.
[0067]
As described above, a titanyl phthalocyanine crystal having a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to CuKα radiation (wavelength: 1.542 °) is obtained by thermal energy / mechanical It is known that a crystal transition easily occurs to another crystal type due to a stress such as a target shear. This tendency does not change in the titanyl phthalocyanine crystal used in the present invention. That is, in order to produce a dispersion liquid containing fine particles, it is necessary to devise a dispersion method. However, there is a tendency that the stability of the crystal form and the formation of fine particles are in a trade-off relationship. There is a method of avoiding this by optimizing the dispersion conditions, but in any case, the production conditions are extremely narrowed, and a simpler method is desired. To solve this problem, the following method is also an effective means.
[0068]
That is, this is a method in which a dispersion liquid in which particles are made as fine as possible within a range in which crystal transition does not occur is produced, and then filtered through an appropriate filter. This method is a very effective means from the viewpoint of removing even small amounts of coarse particles that cannot be observed visually (or cannot be detected by particle size measurement), and that the particle size distribution is uniform. Specifically, the dispersion prepared as described above is filtered through a filter having an effective pore size of 3 μm or less to complete the dispersion. According to this method, a dispersion containing only titanyl phthalocyanine crystal having a small particle size (less than 0.3 μm, preferably 0.25 μm or less, more preferably 0.2 μm or less) can be prepared. By using the body, the effect of the present invention is further enhanced.
[0069]
Next, the electrophotographic photosensitive member used in the present invention will be described in detail with reference to the drawings.
FIG. 5 is a cross-sectional view showing a configuration example of an electrophotographic photoreceptor used in the present invention, in which a charge generation layer (35) containing a charge generation material as a main component and a charge It has a configuration in which a charge transport layer (37) mainly composed of a transport material is laminated.
FIG. 6 is a cross-sectional view showing another example of the configuration of the electrophotographic photoreceptor used in the present invention. On the conductive support (31), an intermediate layer (33) and a charge generation material are mainly used. And a charge transport layer (37) containing a charge transport material as a main component.
[0070]
As the conductive support (31), a volume resistance of 10 ¹⁰ What shows conductivity of Ωcm or less, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver, metals such as platinum, tin oxide, metal oxides such as indium oxide, by evaporation or sputtering, by film Or cylindrical plastic or paper-coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. plates and extruded, drawn out, etc., then tubed, then cut, super-finished, polished, etc. Surface-treated tubes and the like can be used. Further, an endless nickel belt and an endless stainless belt disclosed in JP-A-52-36016 can also be used as the conductive support (31).
[0071]
Among them, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. The aluminum referred to here includes both pure aluminum and aluminum alloy. Specifically, JIS 1000 series, 3000 series, and 6000 series aluminum or aluminum alloy is most suitable. The anodized film is obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, a film called alumite obtained by anodizing aluminum or an aluminum alloy in an electrolyte solution is a photoreceptor used in the present invention. Is most suitable for In particular, it is excellent in preventing point defects (black spots, background stain) generated when used in reversal development (negative / positive development).
[0072]
The anodic oxidation treatment is performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, and sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10 to 20%, bath temperature: 5 to 25 ° C, current density: 1 to 4 A / dm ² The treatment is performed within the range of about 5 to 30 minutes and the treatment time is about 5 to 60 minutes, but the present invention is not limited to this. Since the anodic oxide film thus produced is porous and has high insulation properties, the surface is very unstable. For this reason, there is a temporal change after the production, and the physical property value of the anodic oxide film is likely to change. In order to avoid this, it is desirable to further seal the anodic oxide film. Examples of the sealing treatment include a method of immersing the anodic oxide film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodic oxide film in boiling water, and a method of performing treatment with pressurized steam. Among them, the method of immersing in an aqueous solution containing nickel acetate is most preferable. Subsequent to the sealing treatment, a cleaning treatment of the anodic oxide film is performed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment. If this remains on the surface of the support (anodic oxide film) excessively, it not only adversely affects the quality of the coating film formed thereon, but also generally causes low resistance components to remain. It will also be the cause. The washing may be a single washing with pure water, but usually washing at another stage is performed. At this time, it is preferable that the final cleaning liquid is as clean (deionized) as possible. In addition, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning steps. The thickness of the anodic oxide film formed as described above is desirably about 5 to 15 μm. If it is too thin, the barrier effect of the anodic oxide film is not sufficient, and if it is too thick, the time constant of the electrode becomes too large, resulting in the generation of residual potential and reduced photoconductor response. May be.
[0073]
In addition, a support obtained by dispersing a conductive powder in an appropriate binder resin on the above support and applying the same can also be used as the conductive support (31) of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, and metal oxide powder such as conductive tin oxide and ITO. Can be The binder resin used simultaneously includes polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Thermoplastic, thermosetting resin or photocurable resin such as melamine resin, urethane resin, phenol resin, alkyd resin and the like. Such a conductive layer can be provided by dispersing the conductive powder and the binder resin in an appropriate solvent, for example, tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, or the like, and applying the dispersion.
[0074]
Further, a heat-shrinkable tube containing the above-mentioned conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chloride rubber, and polytetrafluoroethylene-based fluororesin on a suitable cylindrical substrate. A conductive layer provided with a conductive layer can also be favorably used as the conductive support (31) of the present invention.
[0075]
Next, the photosensitive layer will be described. As described above, the photosensitive layer is preferably used as a laminated type composed of the charge generating layer (35) and the charge transporting layer (37), which exhibits excellent characteristics in sensitivity and durability.
[0076]
The charge generation layer (35) has a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to characteristic X-rays of CuKα (wavelength 1.542 °) as a charge generation material. Is a step of converting into a crystalline form). In particular, among the crystal forms, they further have major peaks at 9.4 °, 9.6 °, and 24.0 °, and have a peak at 7.3 ° as the diffraction peak on the lowest angle side, In addition, a titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 ° is preferably used, and a titanyl phthalocyanine crystal having no peak at 26.3 ° is particularly preferable. Used well. Further, the fact that the average particle size of the primary particles of the crystal is less than 0.3 μm (preferably 0.25 μm or less, more preferably 0.2 μm or less) further enhances the effects of the present invention, It is an effective means.
The charge generation layer (35) is obtained by dispersing the pigment in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, and coating the dispersion on a conductive support. It is formed by drying.
[0077]
As necessary, the binder resin used for the charge generation layer (35) may be, for example, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon, or the like. Resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Examples include polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight, per 100 parts by weight of the charge generating substance.
[0078]
Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. As a method of applying the coating solution, a method such as a dip coating method, a spray coat, a beat coat, a nozzle coat, a spinner coat, and a ring coat can be used. The thickness of the charge generation layer 35 is suitably about 0.01 to 5 μm, and preferably 0.1 to 2 μm.
[0079]
The charge transporting layer (37) can be formed by dissolving or dispersing the charge transporting substance and the binder resin in a suitable solvent, applying this on the charge generating layer, and drying. If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.
The charge transport materials include a hole transport material and an electron transport material.
Examples of the electron transporting substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-Tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trione Electron accepting substances such as nitrodibenzothiophene-5,5-dioxide, benzoquinone derivatives and the like.
Examples of the hole transport material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethylglutamate and derivatives thereof, pyrene-formaldehyde condensate and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, and oxazole derivatives. Oxadiazole derivative, imidazole derivative, monoarylamine derivative, diarylamine derivative, triarylamine derivative, stilbene derivative, α-phenylstilbene derivative, benzidine derivative, diarylmethane derivative, triarylmethane derivative, 9-styrylanthracene derivative, pyrazoline Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. And other known materials. These charge transport materials are used alone or in combination of two or more.
[0080]
Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, and poly (vinyl acetate). Vinylidene chloride, polyalate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin And a thermoplastic or thermosetting resin such as an alkyd resin.
The amount of the charge transporting material is suitably 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. Further, the thickness of the charge transport layer is preferably about 5 to 100 μm.
[0081]
As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. Among them, the use of a non-halogen solvent is desirable from the viewpoint of reducing the burden on the environment. Specifically, cyclic ethers such as tetrahydrofuran, dioxolan, and dioxane, aromatic hydrocarbons such as toluene and xylene, and derivatives thereof are preferably used.
[0082]
For the charge transport layer, a polymer charge transport material having both a function as a charge transport material and a function as a binder resin is preferably used. The charge transport layer composed of these polymeric charge transport materials has excellent abrasion resistance. As the polymer charge transporting substance, known materials can be used, and particularly, a polycarbonate containing a triarylamine structure in a main chain and / or a side chain is preferably used. Among them, the polymer charge transporting substances represented by the formulas (I) to (X) are preferably used, and these are exemplified below and specific examples are shown.
[0083]
Embedded image

Where R ₁ , R ₂ , R ₃ Each independently represents a substituted or unsubstituted alkyl group or a halogen atom; ₄ Is a hydrogen atom or a substituted or unsubstituted alkyl group, R ₅ , R ₆ Is a substituted or unsubstituted aryl group, o, p, and q are each independently an integer of 0 to 4, k and j each represent a composition, and 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, and n Represents the number of repeating units and is an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula.
[0084]
Embedded image

Where R ₁₀₁ , R ₁₀₂ Each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers from 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, -O-, -S-, -SO-, -SO ₂ —, —CO—, —CO—O—Z—O—CO— (wherein Z represents an aliphatic divalent group) or
[0085]
Embedded image

(Where a is an integer of 1 to 20, b is an integer of 1 to 2000, R ₁₀₃ , R ₁₀₄ Represents a substituted or unsubstituted alkyl group or aryl group. ). Where R ₁₀₁ And R ₁₀₂ , R ₁₀₃ And R ₁₀₄ May be the same or different.
[0086]
Embedded image

Where R ₇ , R ₈ Is a substituted or unsubstituted aryl group, Ar ₁ , Ar ₂ , Ar ₃ Represents the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I).
[0087]
Embedded image

Where R ₉ , R ₁₀ Is a substituted or unsubstituted aryl group, Ar ₄ , Ar ₅ , Ar ₆ Represents the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I).
[0088]
Embedded image

Where R ₁₁ , R ₁₂ Is a substituted or unsubstituted aryl group, Ar ₇ , Ar ₈ , Ar ₉ Represents the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are the same as in the case of the formula (I).
[0089]
Embedded image

Where R _Thirteen , R ₁₄ Is a substituted or unsubstituted aryl group, Ar ₁₀ , Ar ₁₁ , Ar ₁₂ Are the same or different arylene groups, X ₁ , X ₂ Represents a substituted or unsubstituted ethylene group or a substituted or unsubstituted vinylene group. X, k, j and n are the same as in the case of the formula (I).
[0090]
Embedded image

Where R _Fifteen , R ₁₆ , R ₁₇ , R ₁₈ Is a substituted or unsubstituted aryl group, Ar _Thirteen , Ar ₁₄ , Ar _Fifteen , Ar ₁₆ Is the same or different arylene group, Y ₁ , Y ₂ , Y ₃ Represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, and a vinylene group, which may be the same or different. X, k, j and n are the same as in the case of the formula (I).
[0091]
Embedded image

Where R ₁₉ , R ₂₀ Represents a hydrogen atom, a substituted or unsubstituted aryl group; ₁₉ And R ₂₀ May form a ring. Ar ₁₇ , Ar ₁₈ , Ar ₁₉ Represents the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I).
[0092]
Embedded image

Where R ₂₁ Is a substituted or unsubstituted aryl group, Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , Ar ₂₃ Represents the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I).
[0093]
Embedded image

Where R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ Is a substituted or unsubstituted aryl group, Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ , Ar ₂₈ Represents the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I).
[0094]
Embedded image

Where R ₂₆ , R ₂₇ Is a substituted or unsubstituted aryl group, Ar ₂₉ , Ar ₃₀ , Ar ₃₁ Represents the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I).
[0095]
In addition, as the polymer charge transporting material used in the charge transporting layer, in addition to the above-described polymer charge transporting material, a monomer or oligomer having an electron donating group may be formed at the time of film formation of the charge transporting layer. A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by a curing reaction or a crosslinking reaction.
[0096]
A charge transport layer composed of a polymer having an electron donating group or a polymer having a crosslinked structure has excellent abrasion resistance. Normally, in an electrophotographic process, the charging potential (potential of an unexposed portion) is constant. Therefore, when the surface layer of the photoconductor is worn by repeated use, the electric field intensity applied to the photoconductor increases accordingly. As the electric field intensity increases, the frequency of occurrence of background contamination increases. Therefore, the high wear resistance of the photoconductor is advantageous against background contamination. The charge transport layer composed of a polymer having an electron donating group is excellent in film-forming properties because it is a polymer compound itself, and has a charge transport site as compared with the charge transport layer composed of a low molecular weight dispersed polymer. It can be formed at high density and has excellent charge transporting ability. Therefore, a high-speed response can be expected for a photoreceptor having a charge transport layer using a polymer charge transport material.
[0097]
Other polymers having an electron donating group include copolymers of known monomers, block polymers, graft polymers, star polymers, and, for example, JP-A-3-109406, JP-A-2000- It is also possible to use a crosslinked polymer having an electron donating group as disclosed in JP-A-206723, JP-A-2001-34001 and the like.
[0098]
In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer (37). As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount of the plasticizer is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain are used. 1% by weight is suitable.
[0099]
In the electrophotographic photoreceptor of the present invention, an intermediate layer can be provided between the conductive support (31) and the photosensitive layer. The intermediate layer generally contains a resin as a main component. However, considering that these resins are coated on the photosensitive layer with a solvent, it is preferable that the resin be a resin having high solvent resistance to general organic solvents. . Examples of such a resin include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, copolymer-soluble nylons, alcohol-soluble resins such as methoxymethylated nylon, polyurethane, melamine resins, phenol resins, alkyd-melamine resins, and epoxy resins. Curable resins that form a three-dimensional network structure, such as resins, are exemplified. Further, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide or the like may be added to the intermediate layer in order to prevent moire and reduce residual potential.
[0100]
These intermediate layers can be formed using an appropriate solvent and a coating method as in the above-described photosensitive layer. Further, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the intermediate layer of the present invention. In addition, the intermediate layer of the present invention includes Al ₂ O ₃ Provided by anodic oxidation, organic substances such as polyparaxylylene (parylene) or SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ Also, inorganic materials such as those provided by a vacuum thin film forming method can be used favorably. In addition, known materials can be used. The thickness of the intermediate layer is suitably from 0 to 5 μm.
[0101]
In the electrophotographic photoreceptor of the present invention, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. 2. Description of the Related Art In recent years, computers have been used on a daily basis, and high-speed output by a printer and a small-sized apparatus have been desired. Therefore, by providing a protective layer and improving the durability, the photoconductor of the present invention having high sensitivity and free from abnormal defects can be used effectively.
[0102]
In the photoreceptor of the present invention, a protective layer (39) may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. Materials used for the protective layer (39) include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, and polyallyl sulfone. , Polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyether sulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane And resins such as polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Among them, polycarbonate or polyarylate can be most preferably used.
[0103]
In addition to the protective layer, a fluorine resin such as polytetrafluoroethylene, a silicone resin, and an inorganic filler such as titanium oxide, tin oxide, potassium titanate, silica, etc. A filler or the like dispersed therein can be added.
Further, among the filler materials used for the protective layer of the photoreceptor, examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, and the like. Are metal powders such as copper, tin, aluminum and indium, metals such as silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, antimony-doped tin oxide, and tin-doped indium oxide Inorganic materials such as oxides and potassium titanate are exemplified. Particularly, from the viewpoint of the hardness of the filler, it is advantageous to use an inorganic material among them. In particular, silica, titanium oxide, and alumina can be effectively used.
[0104]
The filler concentration in the protective layer varies depending on the type of filler used and the electrophotographic process conditions using the photoreceptor, but is 5% by weight or more, preferably 5% by weight or more, based on the total solids on the outermost layer side of the protective layer. 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less are good.
The volume average particle diameter of the filler to be used is preferably 0.1 μm to 2 μm, and more preferably 0.3 μm to 1 μm. In this case, if the average particle size is too small, the abrasion resistance is not sufficiently exhibited, and if the average particle size is too large, the surface properties of the coating film deteriorate, or the coating film itself cannot be formed.
[0105]
The average particle size of the filler in the present invention is a volume average particle size unless otherwise specified, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). In this case, the particle diameter was calculated as a particle diameter (Median type) corresponding to 50% of the cumulative distribution. It is important that the standard deviation of each particle measured at the same time is 1 μm or less. If the value of the standard deviation is larger than this, the effect of the present invention may not be obtained remarkably because the particle size distribution is too wide.
Further, the pH of the filler used in the present invention greatly affects the resolution and the dispersibility of the filler. As one of the reasons, it is considered that hydrochloric acid or the like remains during the production of fillers, especially metal oxides. When the residual amount is large, the occurrence of image blur is inevitable, and depending on the residual amount, it may affect the dispersibility of the filler.
[0106]
Another reason is that the chargeability on the surface of the filler, especially the metal oxide, is different. Normally, particles dispersed in a liquid are positively or negatively charged, and ions having the opposite charge gather in an attempt to keep it electrically neutral, where an electric double layer is formed. The dispersion state of the particles is stabilized. As the distance from the particle increases, its potential (zeta potential) gradually decreases, and the potential of a region sufficiently far from the particle and electrically neutral becomes zero. Therefore, the stability increases as the repulsive force of the particles increases due to an increase in the absolute value of the zeta potential, and the particles tend to aggregate and become unstable as the value approaches zero. On the other hand, the zeta potential varies greatly depending on the pH value of the system, and at a certain pH value, the potential becomes zero and has an isoelectric point. Therefore, the dispersion system is stabilized by increasing the absolute value of the zeta potential as far as possible from the isoelectric point of the system.
[0107]
In the constitution of the present invention, as the filler, those having a pH at the above-mentioned isoelectric point of at least 5 are preferable from the viewpoint of suppressing image blur, and the more the filler is more basic, the higher the effect tends to be. It was confirmed that there was. The filler having a high pH at the isoelectric point and exhibiting a basic property has a higher zeta potential when the system is acidic, so that the dispersibility and the stability thereof are improved.
Here, the pH of the filler in the present invention is a pH value at the isoelectric point from the zeta potential. At this time, the zeta potential was measured with a laser zeta potentiometer manufactured by Otsuka Electronics Co., Ltd.
[0108]
Further, as a filler which is less likely to cause image blur, a filler having a high electrical insulation property (a specific resistance of 10 ¹⁰ Ω · cm or more), and those having a filler pH of 5 or more and those having a filler dielectric constant of 5 or more can be used particularly effectively. In addition, a filler having a pH of 5 or more or a filler having a dielectric constant of 5 or more may be used alone, or a mixture of two or more fillers having a pH of 5 or less and a filler having a pH of 5 or more may be used. It is also possible to use a mixture of two or more fillers having a dielectric constant of 5 or less and a filler having a dielectric constant of 5 or more. In addition, among these fillers, α-alumina, which has high insulation properties, high thermal stability, and high wear resistance, has a hexagonal close-packed structure, is used to reduce image blur and improve wear resistance. Especially useful.
[0109]
The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance of a powder such as a filler differs depending on the filling rate, it is necessary to measure the powder under a certain condition. In the present invention, the specific resistance of the filler is measured using an apparatus having the same configuration as the measuring apparatus disclosed in JP-A-5-94049 (FIG. 1) and JP-A-5-113688 (FIG. 1). It measured and used this value. In the measurement device, the electrode area is 4.0 cm2. Before the measurement, a load of 4 kg is applied to one electrode on one side for 1 minute, and the amount of the sample is adjusted so that the distance between the electrodes becomes 4 mm. At the time of the measurement, the measurement is performed under a load state of the weight (1 kg) of the upper electrode, and the applied voltage is measured at 100V. The area of 106 Ω · cm or more was measured with a HIGH RESISTANCE METER (Yokogawa Hewlett-Packard), and the area below 106 Ω · cm was measured with a digital multimeter (Fluke). The specific resistance value thus obtained is defined as the specific resistance value in the present invention.
[0110]
The dielectric constant of the filler was measured as follows. After applying a load using the same cell as that for measuring the specific resistance as described above, the capacitance was measured, and the dielectric constant was determined from this. The capacitance was measured using a dielectric loss meter (Ando Electric).
[0111]
Furthermore, these fillers can be surface-treated with at least one surface treatment agent, and it is preferable to do so from the viewpoint of filler dispersibility. A decrease in the dispersibility of the filler not only increases the residual potential but also causes a decrease in the transparency of the coating film, the occurrence of coating film defects, and a decrease in abrasion resistance, which hinders high durability or high image quality. It can evolve into a big problem. As the surface treatment agent, all the surface treatment agents conventionally used can be used, but a surface treatment agent capable of maintaining the insulating property of the filler is preferable. For example, titanate-based coupling agents, aluminum-based coupling agents, zirco-aluminate-based coupling agents, higher fatty acids, etc., or a mixing treatment of these with a silane coupling agent, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate or the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur. Although the treatment with the silane coupling agent has a strong effect of image blur, the effect of mixing the surface treatment agent and the silane coupling agent may be suppressed in some cases. Although the surface treatment amount varies depending on the average primary particle size of the filler used, 3 to 30 wt% is suitable, and 5 to 20 wt% is more preferable. If the amount of the surface treatment is smaller than this, the effect of dispersing the filler cannot be obtained, and if the amount is too large, the residual potential is significantly increased. These filler materials are used alone or in combination of two or more. The surface treatment amount of the filler is defined by the weight ratio of the surface treatment agent used to the filler amount as described above.
[0112]
These filler materials can be dispersed by using an appropriate disperser. Further, from the viewpoint of the transmittance of the protective layer, it is preferable that the filler used is dispersed to the level of the primary particles and the amount of the aggregate is small.
[0113]
Further, the protective layer (39) may contain a charge transporting substance for reducing residual potential and improving responsiveness. As the charge transporting substance, the materials described in the description of the charge transporting layer can be used. When a low molecular charge transport material is used as the charge transport material, a concentration gradient in the protective layer may be provided. It is an effective means to reduce the concentration on the surface side in order to improve abrasion resistance. Here, the concentration refers to the ratio of the weight of the low-molecular charge transporting substance to the total weight of all the materials constituting the protective layer, and the concentration gradient is such that the concentration decreases on the surface side at the above weight ratio. It indicates that. The use of a charge transport polymer is very advantageous in that the durability of the photoreceptor is improved.
[0114]
An ordinary coating method is adopted as a method for forming the protective layer. The thickness of the protective layer is suitably about 0.1 to 10 μm. In addition to the above, known materials such as aC and a-SiC formed by a vacuum thin film forming method can be used as the protective layer.
[0115]
As described above, the use of a polymeric charge transport material in the photosensitive layer (charge transport layer) or the provision of a protective layer on the surface of the photoconductor increases the durability (wear resistance) of each photoconductor. In addition, when used in a tandem-type full-color image forming apparatus as described below, it produces a new effect not found in a monochrome image forming apparatus.
[0116]
In the case of a full-color image, various types of images are input. On the contrary, a standard image may be input. For example, the presence of a seal in a Japanese document or the like. Something like a seal is usually located near the edge of the image area and also uses a limited number of colors. In a state where a random image is always written, image writing, development and transfer are performed on the photoreceptor in the image forming element on average. When a large number of image formations are repeated or when only a specific image formation element is used, the durability of the image formation element is not balanced. When a photoreceptor having a small surface durability (physical, chemical, mechanical) is used in such a state, the difference becomes remarkable, which tends to cause an image problem. On the other hand, when the photoreceptor is made highly durable, such a local change amount is small, and as a result, it becomes difficult to appear as a defect on an image. It is also very effective.
[0117]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited by the examples. All parts are parts by weight.
First, a synthesis example of the charge generation material used in the present invention will be described.
(Synthesis example 1)
29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C, and the reaction was carried out with stirring for 5 hours while maintaining the reaction temperature between 170 ° C and 180 ° C. After the reaction, the precipitate was filtered after standing to cool, washed with chloroform until the powder turned blue, then washed with methanol several times, further washed with hot water of 80 ° C. several times, and dried. Crude titanyl phthalocyanine was obtained. The crude titanyl phthalocyanine is dissolved in 20 times the volume of concentrated sulfuric acid, dropped into 100 volumes of the ice water with stirring, the precipitated crystals are filtered, and the water washing is repeated until the washing solution becomes neutral. (Water paste) was obtained. 2 g of the obtained wet cake (water paste) was added to 20 g of tetrahydrofuran and stirred for 4 hours. 100 g of methanol was added thereto, and the mixture was stirred for 1 hour, filtered, and dried to obtain a titanyl phthalocyanine powder of the present invention.
The obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions. As a result, the maximum peak and the minimum angle at a Bragg angle 2θ of 27.2 ± 0.2 ° with respect to Cu-Kα ray (wavelength 1.542 °) were 7 A titanyl phthalocyanine powder having a peak at 0.3 ± 0.2 ° and having no peak in the range of 7.4 to 9.4 ° was obtained. FIG. 7 shows the result.
A part of the water paste obtained in Synthesis Example 1 was dried at 80 ° C. under reduced pressure (5 mmHg) for 2 days to obtain low crystalline titanyl phthalocyanine powder. FIG. 13 shows the X-ray diffraction spectrum of the dried powder of the water paste.
[0118]
(X-ray diffraction spectrum measurement conditions)
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min
Scanning range: 3 ° to 40 °
Time constant: 2 seconds
[0119]
(Synthesis example 2)
A pigment was prepared according to the method described in JP-A-1-299874 (Japanese Patent No. 2512081) and Example 1. That is, the wet cake prepared in Synthesis Example 1 was dried, 1 g of the dried product was added to 50 g of polyethylene glycol, and a sand mill was performed together with 100 g of glass beads. After the crystal transition, the resultant was washed with dilute sulfuric acid and an aqueous solution of ammonium hydroxide in that order and dried to obtain a pigment.
[0120]
(Synthesis example 3)
A pigment was prepared according to the method described in Production Example 1 of JP-A-3-269064 (Japanese Patent No. 2584682). That is, the wet cake prepared in Synthesis Example 1 was dried, and 1 g of the dried product was stirred (50 ° C.) for 1 hour in a mixed solvent of 10 g of ion-exchanged water and 1 g of monochlorobenzene, and then washed with methanol and ion-exchanged water. And dried to obtain a pigment.
[0121]
(Synthesis example 4)
A pigment was prepared according to the method described in the production example of JP-A-2-8256 (JP-B-7-91486). That is, 9.8 g of phthalodinitrile and 75 ml of 1-chloronaphthalene are stirred and mixed, and 2.2 ml of titanium tetrachloride is added dropwise under a nitrogen stream. After the completion of the dropwise addition, the temperature was gradually raised to 200 ° C, and the reaction was carried out with stirring for 3 hours while maintaining the reaction temperature between 200 ° C and 220 ° C. After the completion of the reaction, the mixture was allowed to cool to 130 ° C., filtered while hot, then washed with 1-chloronaphthalene until the powder turned blue, washed several times with methanol, and further washed with hot water at 80 ° C. After washing twice, it was dried to obtain a pigment.
[0122]
(Synthesis example 5)
A pigment was prepared according to the method described in JP-A No. 64-17066 (JP-B-7-97221) and Synthesis Example 1. That is, 5 parts of α-type TiOPc was subjected to a crystal conversion treatment at 100 ° C. for 10 hours with a sand grinder together with 10 g of sodium chloride and 5 g of acetophenone. This was washed with ion-exchanged water and methanol, purified with a dilute aqueous sulfuric acid solution, washed with ion-exchanged water until the acid content disappeared, and then dried to obtain a pigment.
[0123]
(Synthesis example 6)
A pigment was prepared according to the method described in JP-A-11-5919 (Japanese Patent No. 3003664) and Example 1. That is, after 20.4 parts of O-phthalodinitrile and 7.6 parts of titanium tetrachloride were heated and reacted in 50 parts of quinoline at 200 ° C. for 2 hours, the solvent was removed by steam distillation, followed by a 2% aqueous chloride solution, The product was purified with a 2% aqueous sodium hydroxide solution, washed with methanol and N, N-dimethylformamide, and dried to obtain titanyl phthalocyanine. 2 parts of this titanyl phthalocyanine is dissolved little by little in 40 parts of 98% sulfuric acid at 5 ° C., and the mixture is stirred for about 1 hour while maintaining the temperature at 5 ° C. or less. Subsequently, the sulfuric acid solution is slowly poured into 400 parts of ice water with high-speed stirring, and the precipitated crystals are filtered. The crystals are washed with distilled water until no acid remains, to obtain a wet cake. The cake was stirred in 100 parts of THF for about 5 hours, filtered, washed with THF and dried to obtain a pigment.
[0124]
(Synthesis example 7)
A pigment was prepared according to the method described in JP-A-3-255456 (Japanese Patent No. 3005052) and Synthesis Example 2. That is, 10 parts of the wet cake prepared in Synthesis Example 1 described above was mixed with 15 parts of sodium chloride and 7 parts of diethylene glycol, and milling was performed for 60 hours in an automatic mortar under heating at 80 ° C. Next, the treated product was sufficiently washed with water to completely remove sodium chloride and diethylene glycol. After drying under reduced pressure, 200 parts of cyclohexanone and glass beads having a diameter of 1 mm were added, and the mixture was treated by a sand mill for 30 minutes to obtain a pigment.
[0125]
(Synthesis example 8)
According to the method of Synthesis Example 1, a water paste of a titanyl phthalocyanine pigment was synthesized, and the crystal conversion was performed as described below to obtain a phthalocyanine crystal having smaller primary particles than in Synthesis Example 1.
1500 parts of tetrahydrofuran was added to 60 parts of the water paste obtained before the crystal transformation obtained in Synthesis Example 1, and the mixture was vigorously stirred (2000 rpm) at room temperature with a homomixer (Kennis, MARKIIf model), and the dark blue color of the paste was pale. When the color changed to blue (20 minutes after the start of stirring), the stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filtration device were washed with tetrahydrofuran to obtain a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 58 parts of titanyl phthalocyanine crystals.
[0126]
A part of titanyl phthalocyanine before crystal conversion (water paste) prepared in Synthesis Example 1 was diluted with ion-exchanged water to about 1% by weight, and the surface was scooped with a copper net having a conductive treatment. Was observed at a magnification of 75,000 times with a transmission electron microscope (TEM, Hitachi: H-9000NAR). The average particle size was determined as follows.
[0127]
The TEM image observed as described above is taken as a TEM photograph, and 30 projected titanyl phthalocyanine particles (near needle-like shape) are arbitrarily selected, and the size of the major axis is measured. The arithmetic average of the longer diameters of the 30 individuals measured was determined to be the average particle size.
The average particle size in the water paste in Synthesis Example 1 determined by the above method was 0.06 μm.
[0128]
In addition, titanyl phthalocyanine crystals after the crystal conversion immediately before filtration in Synthesis Examples 1 and 8 were diluted with tetrahydrofuran to about 1% by weight, and observation was performed in the same manner as in the above method. Table 1 shows the average particle size determined as described above. Note that the titanyl phthalocyanine crystals produced in Synthesis Examples 1 and 8 did not necessarily have the same crystal shape (a shape close to a triangle, a shape close to a square, and the like). For this reason, the calculation was performed with the length of the largest diagonal line of the crystal as the major axis.
[0129]
[Table 1]

[0130]
The X-ray diffraction spectra of the pigments prepared in Synthesis Examples 2 to 7 were measured in the same manner as described above, and it was confirmed that the spectra were the same as those described in the respective publications. Further, the X-ray diffraction spectrum of the pigment prepared in Synthesis Example 8 coincided with the spectrum of the pigment prepared in Synthesis Example 1. Table 2 shows the characteristics of each X-ray diffraction spectrum and the peak position of the X-ray diffraction spectrum of the pigment obtained in Synthesis Example 1.
[0131]
[Table 2]

[0132]
(Photoconductor production example 1)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions are sequentially applied to an aluminum cylinder (JIS 1050) having a diameter of 60 mm and dried, and a 3.5 μm undercoat layer is formed. A charge generating layer and a 25 μm charge transporting layer were formed to produce a laminated photoreceptor (referred to as photoreceptor 1). The thickness of the charge generation layer was adjusted so that the transmittance of the charge generation layer at 780 nm was 20%. The transmittance of the charge generation layer was determined by applying a charge generation layer coating solution having the following composition to an aluminum cylinder around which a polyethylene terephthalate film was wound under the same conditions as in the preparation of the photoreceptor. The polyethylene terephthalate film was not used, and the transmittance at 780 nm was evaluated using a commercially available spectrophotometer (Shimadzu: UV-3100).
◎ Undercoat layer coating liquid
Titanium oxide (CR-EL: Ishihara Sangyo Co., Ltd.) 70 parts
Alkyd resin 15 parts
(Beccolite M6401-50-S (solid content 50%), manufactured by Dainippon Ink and Chemicals, Inc.)
Melamine resin 10 parts
(Super Beckamine L-121-60 (solid content 60%), manufactured by Dainippon Ink and Chemicals, Inc.)
2-butanone 100 parts
◎ Coating solution for charge generation layer
A dispersion having the following composition was prepared by bead milling under the following conditions.
15 parts of titanyl phthalocyanine pigment prepared in Synthesis Example 1
Polyvinyl butyral (Sekisui Chemical: BX-1) 10 parts
280 parts of 2-butanone
Using a commercially available bead mill disperser, a PSZ ball having a diameter of 0.5 mm was used, and all 2-butanone and pigment in which polyvinyl butyral was dissolved were charged. p. m. For 30 minutes to prepare a dispersion.
The particle size distribution of the pigment particles in this dispersion was measured by HORIBA, Ltd .: CAPA-700. As a result, the average particle size was 0.29 μm, and the standard deviation was 0.18 μm.
◎ Coating solution for charge transport layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0133]
Embedded image

80 parts of methylene chloride
[0134]
(Photoreceptor Preparation Examples 2 to 8)
Photoconductor preparation, except that the titanyl phthalocyanine pigment used in the charge generation layer coating liquid used in photoconductor preparation example 1 (prepared in Synthesis Example 1) was changed to the titanyl phthalocyanine pigment prepared in Synthesis Examples 2 to 8, respectively A photoconductor was produced in the same manner as in Example 1. The thickness of the charge generation layer was adjusted so that the transmittance at 780 nm was 20% when all the coating liquids were used, as in Photoconductor Preparation Example 1.
[0135]
(Photoconductor Production Example 9)
The coating liquid for the charge generation layer used in Photoreceptor Preparation Example 1 was filtered before coating using a cotton wind cartridge filter (TCW-3-CS, effective pore diameter: 3 μm) manufactured by Advantech Co., Ltd. At the time of filtration, a filtration was performed under pressure using a pump.
[0136]
(Photoconductor Production Example 10)
The coating liquid for the charge generation layer used in Photoreceptor Preparation Example 1 was filtered using a cotton wind cartridge filter (TCW-1-CS, effective pore diameter: 1 μm) manufactured by Advantech before coating. At the time of filtration, a filtration was performed under pressure using a pump.
[0137]
(Photoconductor Production Example 11)
The coating liquid for the charge generation layer used in Photoreceptor Preparation Example 1 was filtered using a cotton wind cartridge filter, TCW-5-CS (effective pore diameter 5 μm) manufactured by Advantech Co., Ltd. before coating. At the time of filtration, a filtration was performed under pressure using a pump.
[0138]
(Examples 1 to 5 and Comparative Examples 1 to 17)
The electrophotographic photoreceptors of Photoreceptor Production Examples 1 to 11 prepared as described above were mounted on the electrophotographic apparatus shown in FIG. Using a contact type charging roller and a transfer belt as a transfer member, the image after continuous printing of 200,000 sheets was evaluated using a chart with a writing rate of 6% under the following charging and transfer conditions. The presence or absence was confirmed (the test environment was 22 ° C.-55% RH). At this time, the transfer current was controlled by a circuit as shown in FIG. In addition, evaluation was performed in four steps, and ◎ indicates very good, ◎ indicates good, △ indicates slightly inferior, and × indicates very poor. Table 3 shows the above results.
[0139]
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (Peak to peak), frequency: 1.5 kHz
Transfer conditions:
Two conditions of 75μA and 60μA
[0140]
[Table 3]

[0141]
(Photoconductor Production Example 12)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating liquid for the charge transport layer in Photoconductor Preparation Example 1 was changed to one having the following composition.
◎ Coating solution for charge transport layer
Polymer charge transport material of the following composition 10 parts
(Weight average molecular weight: about 135000)
[0142]
Embedded image

0.5 parts of additives with the following structure
[0143]
Embedded image

100 parts of methylene chloride
[0144]
(Photoconductor Production Example 13)
Same as Photoreceptor Preparation Example 1 except that the thickness of the charge transport layer in Photoreceptor Preparation Example 1 was set to 20 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a protective layer of 5 μm was provided. A photosensitive member was prepared.
◎ Coating solution for protective layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0145]
Embedded image

Alumina fine particles 4 parts
(Specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.4 μm)
Cyclohexanone 500 parts
150 parts of tetrahydrofuran
[0146]
(Photoconductor Production Example 14)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 13, except that the alumina fine particles in the protective layer coating liquid in Photoconductor Preparation Example 13 were changed to the following.
4 parts of titanium oxide fine particles
(Specific resistance: 1.5 × 10 ¹⁰ Ω · cm, average primary particle size: 0.5 μm)
[0147]
(Photoconductor Production Example 15)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 13, except that the alumina fine particles in the protective layer coating liquid in Photoconductor Preparation Example 13 were changed to the following.
Tin oxide-antimony oxide powder 4 parts
(Specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
[0148]
(Photoconductor Production Example 16)
The aluminum cylinder (JIS 1050) in Photoreceptor Production Example 1 was subjected to the following anodic oxide film treatment, and then a charge generation layer and a charge transport layer were provided in the same manner as in Photoreceptor Production Example 1 without providing an undercoat layer. Was prepared.
◎ Anodized film treatment
The surface of the support was mirror-polished, degreased and washed with water, immersed in an electrolytic bath of a liquid temperature of 20 ° C. and 15 vol% of sulfuric acid, and subjected to an anodic oxide film treatment at an electrolytic voltage of 15 V for 30 minutes. Further, after water washing, sealing treatment was performed with a 7% nickel acetate aqueous solution (50 ° C.). Thereafter, the substrate was washed with pure water to obtain a support having a 7 μm anodic oxide film formed thereon.
[0149]
(Examples 6 to 14 and Comparative Examples 18 to 23)
The electrophotographic photoreceptors of the photoreceptor preparation examples 1 to 16 prepared as described above are mounted on the electrophotographic apparatus shown in FIG. 1, and an image exposure light source is a 780 nm semiconductor laser (image writing by a polygon mirror), and a charging member is used. As a charging member, as shown in FIG. 2, a charging member for proximity placement (a gap between the photoreceptor and the surface of the charging member is 50 μm) in which a 50 μm-thick insulating tape is wrapped around both ends of the charging roller is used. Using a chart with a writing rate of 6% under transfer conditions, the presence or absence of background stain after continuous printing of 200,000 sheets and a halftone image were confirmed (the test environment was 22 ° C.-55% RH). At this time, the transfer current was controlled by a circuit as shown in FIG. In addition, the evaluation of the background dirt was carried out in four stages. Very good ones were indicated by ◎, good ones were indicated by ○, slightly poor ones by Δ, and very poor ones by X. Further, the abrasion loss of the photosensitive layer after the printing of 200,000 sheets (or the abrasion loss of the protection layer in the case of having a protection layer) was measured. Table 4 shows the above results.
[0150]
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (Peak to peak), frequency: 1.5 kHz
Transfer conditions:
90 μA
[0151]
[Table 4]

[0152]
(Example 16)
In Example 6, after a paper-passing test of 200,000 sheets, a halftone image was output under a 30 ° C.-90% RH environment, and the image was evaluated.
[0153]
(Example 17)
The charging member in Example 6 was changed from the charging member for proximity arrangement to a scorotron charger, and the surface potential of the non-image portion of the photosensitive member was set to be the same as in Example 6 (-900 V). A paper passing test of 200,000 sheets was performed in the same manner as in Example 6 without changing other conditions. After the paper passing test, a halftone image was output under a 30 ° C.-90% RH environment in the same manner as in Example 15 to evaluate the image.
[0154]
(Example 18)
The charging member in Example 6 was changed from the charging member for proximity arrangement to the charging member for contact (no gap), and the charging conditions were set to the same conditions as in Example 6. A paper passing test of 200,000 sheets was performed in the same manner as in Example 6 without changing other conditions. After the paper passing test, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Example 16 to evaluate the image.
[0155]
(Example 19)
Evaluation was performed in the same manner as in Example 18 except that the charging conditions in Example 18 were changed as follows.
Charging conditions:
DC bias: -1600 V (surface potential of non-image area of photoreceptor in initial state is -900 V)
AC bias: None
[0156]
(Example 20)
Evaluation was performed in the same manner as in Example 6, except that the charging conditions in Example 6 were changed as follows. After a paper passing test of 200,000 sheets, a halftone image was output under an environment of 30 ° C. and 90% RH in the same manner as in Example 16 to evaluate the image.
Charging conditions:
DC bias: -1600 V (surface potential of non-image area of photoreceptor in initial state is -900 V)
AC bias: None
[0157]
(Example 21)
Evaluation was performed in the same manner as in Example 6, except that the gap of the charging member (proximity charging roller) used in Example 6 was changed to 100 μm. After a paper passing test of 200,000 sheets, a halftone image was output under an environment of 30 ° C. and 90% RH in the same manner as in Example 16 to evaluate the image.
[0158]
(Example 22)
Evaluation was performed in the same manner as in Example 6, except that the gap of the charging member (proximity charging roller) used in Example 6 was changed to 150 μm. After a paper passing test of 200,000 sheets, a halftone image was output under an environment of 30 ° C. and 90% RH in the same manner as in Example 16 to evaluate the image.
[0159]
(Example 23)
Evaluation was performed in the same manner as in Example 16 except that the gap of the charging member (proximity charging roller) used in Example 16 was changed to 250 μm. After a paper passing test of 200,000 sheets, a halftone image was output under an environment of 30 ° C. and 90% RH in the same manner as in Example 16 to evaluate the image.
[0160]
(Example 24)
In Example 7, after a 200,000-sheet passing test, a halftone image was output in an environment of 30 ° C. and 90% RH, and the image was evaluated.
[0161]
(Example 25)
After a paper passing test of 200,000 sheets in Example 8, a halftone image was output under a 30 ° C.-90% RH environment, and the image was evaluated.
Table 5 shows the evaluation results in Examples 16 to 25 described above.
[0162]
[Table 5]

[0163]
(Photoconductor Production Example 17)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Coating solution for charge transport layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0164]
Embedded image

80 parts of tetrahydrofuran
[0165]
(Photoconductor production example 18)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 6, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 6 was changed to the following composition.
◎ Coating solution for charge transport layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0166]
Embedded image

80 parts of tetrahydrofuran
[0167]
(Photoconductor Production Example 19)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Coating solution for charge transport layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0168]
Embedded image

Dioxolan 80 parts
[0169]
(Photoconductor Production Example 20)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Coating solution for charge transport layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0170]
Embedded image

40 parts of tetrahydrofuran
40 parts of toluene
[0171]
(Photoconductor Production Example 21)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 8, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 8 was changed to the following composition.
◎ Coating solution for charge transport layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0172]
Embedded image

80 parts of tetrahydrofuran
[0173]
(Photoconductor Production Example 22)
A photoreceptor was prepared in the same manner as in Photoreceptor Preparation Example 9, except that the coating composition for the charge transport layer in Photoreceptor Preparation Example 9 was changed to the following composition.
◎ Coating solution for charge transport layer
Polycarbonate (TS2050: manufactured by Teijin Chemicals) 10 parts
7 parts of charge transport material of the following structural formula
[0174]
Embedded image

80 parts of tetrahydrofuran
[0175]
(Examples 26 to 30 and Comparative Example 24)
The photoreceptors of Photoreceptor Production Examples 17 to 22 produced as described above were mounted on the electrophotographic apparatus shown in FIG. 1 in the same manner as in Example 1, and the image exposure light source was a 780 nm semiconductor laser (using a polygon mirror). As an image writing), a halftone line image was output under the following charging and transfer conditions using a contact type charging roller as a charging member. At this time, the transfer current was controlled by a circuit as shown in FIG. Table 6 shows the results together with Example 1 and Comparative Example 5.
[0176]
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (peak to peak), frequency: 1.5 kHz
Transfer conditions:
110 μA
[0177]
[Table 6]

[0178]
(Photoconductor Production Example 23)
A photoconductor having the same composition as that of the photoconductor preparation example 1 was manufactured by changing the aluminum cylinder of the photoconductor preparation example 1 to one having a diameter of 30 mm.
[0179]
(Photoconductor Production Example 24)
A photoconductor having the same composition as that of Photoconductor Production Example 4 was manufactured by changing the aluminum cylinder of Photoconductor Production Example 4 to a cylinder having a diameter of 30 mm.
[0180]
(Photoconductor Production Example 25)
A photoconductor having the same composition as that of Photoconductor Production Example 5 was produced by changing the aluminum cylinder of Photoconductor Production Example 5 to a cylinder having a diameter of 30 mm.
[0181]
(Example 26 of photoconductor production)
A photoconductor having the same composition as that of Photoconductor Production Example 8 was produced by changing the aluminum cylinder of Photoconductor Production Example 8 to a cylinder having a diameter of 30 mm.
[0182]
(Photoconductor Production Example 27)
A photoconductor having the same composition as that of Photoconductor Production Example 9 was manufactured by changing the aluminum cylinder of Photoconductor Production Example 9 to a cylinder having a diameter of 30 mm.
[0183]
(Examples 31 to 33 and Comparative Examples 25 to 31)
The photoreceptors of the photoreceptor production examples 23 to 27 produced as described above were mounted on one electrophotographic apparatus process cartridge together with the charging member, and further mounted on a full-color electrophotographic apparatus shown in FIG. The four image forming elements were subjected to a pass-through test of 200,000 sheets of a full-color image under the process conditions described below, to confirm the presence of missing characters, the presence or absence of background contamination, and the evaluation of a halftone image (test environment: 22 ° C.-55 % RH). At this time, the transfer current was controlled by a circuit as shown in FIG. In addition, character omission and background stain evaluation were carried out in four stages. Very good ones were represented by ◎, good ones were represented by ○, slightly poor ones by Δ, and very poor ones by X. Table 7 shows the above results.
[0184]
Charging condition: DC bias -800V,
AC bias 1.5 kV (peak to peak),
Frequency 2.0kHz
Charging member: the same as that used in Example 2
Writing: 780nm LD (using polygon mirror)
Transfer conditions: 2 conditions of 75 μA and 60 μA
[0185]
[Table 7]

[0186]
Finally, it is verified whether the lowest angle peak of 7.3 ° of the Bragg angle θ, which is a feature of the titanyl phthalocyanine crystal used in the present invention, is the same as the lowest angle of known materials of 7.5 °.
[0187]
(Synthesis example 9)
The same treatment as in Synthesis Example 1 was carried out except that the crystal conversion solvent in Synthesis Example 1 was changed from methylene chloride to 2-butanone, to obtain a titanyl phthalocyanine crystal.
The XD spectrum of the titanyl phthalocyanine crystal prepared in Synthesis Example 9 was measured in the same manner as in Synthesis Example 1. This is shown in FIG. 8, the lowest angle in the XD spectrum of the titanyl phthalocyanine crystal produced in Synthesis Example 9 is at 7.5 °, which is different from the lowest angle (7.3 °) of the titanyl phthalocyanine produced in Synthesis Example 1. You can see.
[0188]
(Measurement example 1)
The pigment (lowest angle 7.3 °) obtained in Synthesis Example 1 was prepared in the same manner as the pigment described in JP-A-61-239248 (having the maximum diffraction peak at 7.5 °), and 3% by weight. % And mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as above. The X-ray diffraction spectrum of Measurement Example 1 is shown in FIG.
[0189]
(Measurement example 2)
The pigment obtained in Synthesis Example 9 (minimum angle 7.5 °) was prepared in the same manner as the pigment described in JP-A-61-239248 (having the maximum diffraction peak at 7.5 °), and 3% by weight. % And mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as above. The X-ray diffraction spectrum of Measurement Example 2 is shown in FIG.
[0190]
In the spectrum of FIG. 9, two independent peaks of 7.3 ° and 7.5 ° exist on the low-angle side, and it can be seen that at least the peaks of 7.3 ° and 7.5 ° are different. . On the other hand, in the spectrum of FIG. 10, the low-angle side peak exists only at 7.5 °, which is clearly different from the spectrum of FIG.
From the above, it can be seen that the lowest angle peak of 7.3 ° in the titanyl phthalocyanine crystal of the present invention is different from the peak of 7.5 ° in the known titanyl phthalocyanine crystal.
[0191]
【The invention's effect】
As described above, as is clear from the detailed and specific inventions, according to the present invention, there is provided an electrophotographic apparatus which does not generate an abnormal image and outputs a stable and high-resolution image when repeatedly used at a high speed. You.
Specifically, there is provided an electrophotographic apparatus which eliminates electrical deterioration of a photoconductor due to reverse charging in a transfer unit and outputs a stable and high-resolution image. Further, even when a non-halogen solvent is used in the coating solution for the charge transport layer, an electrophotographic apparatus which maintains the high sensitivity inherent in titanyl phthalocyanine is provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining an electrophotographic process and an electrophotographic apparatus of the present invention.
FIG. 2 is a view showing an example of a proximity charging mechanism in which a gap forming member is arranged on a charging member side in the present invention.
FIG. 3 is a view for explaining a process cartridge for an electrophotographic apparatus of the present invention.
FIG. 4 is a schematic view illustrating a tandem type full-color electrophotographic apparatus according to the present invention.
FIG. 5 is a diagram illustrating a layer configuration of an electrophotographic photosensitive member used in the present invention.
FIG. 6 is a diagram illustrating a layer configuration of another electrophotographic photosensitive member used in the present invention.
FIG. 7 is a view showing an XD spectrum of titanyl phthalocyanine synthesized in Synthesis Example 1.
FIG. 8 is a diagram showing an XD spectrum of titanyl phthalocyanine synthesized in Synthesis Example 9.
FIG. 9 is a diagram showing an XD spectrum of titanyl phthalocyanine used in Measurement Example 1.
FIG. 10 is a diagram showing an XD spectrum of titanyl phthalocyanine used in Measurement Example 2.
FIG. 11 is a diagram illustrating a relationship between transfer current and transfer efficiency.
FIG. 12 is a diagram illustrating an example of a transfer circuit capable of constant current control.
FIG. 13 is a diagram showing an XD spectrum of a dry powder of a water paste.
FIG. 14 is a diagram showing a state of a dispersion when a dispersion time is short.
FIG. 15 is a diagram showing a state of a dispersion when a dispersion time is long.
FIG. 16 is a diagram showing the average particle size and the particle size distribution of the dispersions of FIGS.
FIG. 17 is a TEM image of amorphous titanyl phthalocyanine. The scale bar in the figure is 0.2 μm.
FIG. 18 is a TEM image of titanyl phthalocyanine after crystal conversion. The scale bar in the figure is 0.2 μm.
FIG. 19 is a TEM image of a titanyl phthalocyanine crystal obtained by performing a crystal conversion in a short time. The scale bar in the figure is 0.2 μm.
[Explanation of symbols]
1 Photoconductor
1C photoreceptor
1M photoreceptor
1Y photoreceptor
1K photoreceptor
2 Static elimination lamp
2C charging member
2M charging member
2Y charging member
2K charging member
3 charging roller
3C laser light
3M laser light
3Y laser light
3K laser light
4C developing member
4M developing member
4Y developing member
4K developing member
5 Image exposure section
5C cleaning member
5M cleaning member
5Y cleaning member
5K cleaning member
6 Developing unit
6C imaging element
6M imaging element
6Y imaging element
6K image forming element
7 Transfer paper
8 Paper feed rollers
9 Registration roller
10 Transfer conveyor belt
11 Transfer bias roller
11C transfer brush
11M transfer brush
11Y transfer brush
11K transfer brush
12 Fixing device
13 Charger before cleaning
14 fur brush
15 Cleaning brush
16 Developing roller
17 Transfer roller
18 Separating claws
21 Gap forming member
22 Metal shaft
23 Image formation area
24 Non-image forming area
31 conductive support
33 middle class
35 charge generation layer
37 charge transport layer
100 photoconductor
101 transfer belt
102 drive roller
103 driven roller
104 bias roller
105 High voltage power supply (power pack)
106 Current detection resistor

Claims (22)

In an electrophotographic apparatus including at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member, a transfer current applied from the transferring unit to the photosensitive member is 65 μA or more, and the electrophotographic photosensitive member is Is an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are sequentially laminated on a conductive support, and a diffraction peak at a Bragg angle of 2θ with respect to CuKα ray (wavelength: 1.542 °) in the charge generation layer. ± 0.2 °), has a maximum diffraction peak at least at 27.2 °, further has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has the lowest angle side. An electrophotograph comprising a titanyl phthalocyanine crystal having a diffraction peak at 7.3 ° and having no peak between the 7.3 ° peak and the 9.4 ° peak. apparatus. 2. The electrophotographic apparatus according to claim 1, wherein the transfer current is controlled by constant current control. A current measuring means provided in a feedback mechanism for feeding back a bypass current flowing from the power supply to the transfer member without flowing from the power supply to the photoreceptor to the power supply, whereby the output current from the power supply and the current measuring means are measured. 3. The electrophotographic apparatus according to claim 1, wherein a transfer current flowing through the photoconductor as a difference from the applied current is controlled. The electrophotographic apparatus according to any one of claims 1 to 3, wherein the titanyl phthalocyanine crystal further has no peak at 26.3 °. 5. The electrophotographic apparatus according to claim 1, wherein the titanyl phthalocyanine crystal has an average primary particle size of less than 0.3 [mu] m. Dispersion is performed until the titanyl phthalocyanine crystal particles have a volume average particle diameter of 0.3 μm or less and a standard deviation of 0.2 μm or less, and then use a dispersion obtained by filtering with a filter having an effective pore diameter of 3 μm or less. 6. The electrophotographic apparatus according to claim 5, wherein a photoconductor coated with a charge generation layer is used. The titanyl phthalocyanine crystal has a maximum diffraction peak at least at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to characteristic X-rays of CuKα (wavelength 1.542 °), Amorphous titanyl phthalocyanine or low-crystalline titanyl phthalocyanine having an average size of 0.1 μm or less of primary particles having a half width of the diffraction peak of 1 ° or more is subjected to crystal transformation with an organic solvent in the presence of water, and after the crystal transformation. 6. The electrophotographic apparatus according to claim 5, wherein the titanyl phthalocyanine after the crystal conversion is separated from the organic solvent and filtered before the primary particles have an average size of 0.3 [mu] m or more. The electrophotographic apparatus according to any one of claims 1 to 7, wherein the charge transport layer contains a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain. The electrophotographic apparatus according to claim 1, further comprising a protective layer on the charge transport layer. The electrophotographic apparatus according to claim 9, wherein the protective layer contains an inorganic pigment or a metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more. The metal oxide is, specific resistance 10 ¹⁰ Omega · cm or more alumina, electrophotographic apparatus according to claim 10, characterized in that either titanium oxide, silica. The electrophotographic apparatus according to claim 10, wherein the metal oxide is α-alumina having a specific resistance of 10 ¹⁰ Ω · cm or more. 13. The electrophotographic apparatus according to claim 9, wherein the protective layer contains a polymer charge transport material. 14. The electrophotographic apparatus according to claim 1, wherein the charge transport layer of the photoconductor is formed using a non-halogen solvent. 15. The electrophotographic apparatus according to claim 14, wherein the non-halogen solvent is at least one selected from cyclic ethers and aromatic hydrocarbons. The electrophotographic apparatus according to any one of claims 1 to 15, wherein a surface of the electroconductive support of the electrophotographic photosensitive member has been subjected to an anodic oxide film treatment. 17. The electrophotographic apparatus according to claim 1, wherein a plurality of image forming elements including at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member are arranged. 18. The electrophotographic apparatus according to claim 1, wherein a contact charging system is used for a charging unit of the electrophotographic apparatus. 18. The electrophotographic apparatus according to claim 1, wherein a non-contact close arrangement method is used for a charging unit of the electrophotographic apparatus. 20. The electrophotographic apparatus according to claim 19, wherein a gap between the charging member used for the charging unit and the photoconductor is 200 [mu] m or less. 21. The electrophotographic apparatus according to claim 18, wherein an AC superimposed voltage is applied to a charging unit of the electrophotographic apparatus. 22. The apparatus according to claim 1, further comprising a device main body in which a photosensitive member and at least one of a charging unit, an exposing unit, a developing unit, and a cleaning unit are integrated, and a removable cartridge. The electrophotographic apparatus according to any one of the above.

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