JP4046333B2 - Titanyl phthalocyanine crystal, method for producing titanyl phthalocyanine crystal, electrophotographic photosensitive member, electrophotographic method, electrophotographic apparatus, and process cartridge for electrophotographic apparatus - Google Patents

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又はハロゲン原子、Ｒ_４は水素原子又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。なお、（Ｉ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６０】
【化２】

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、
【００６１】
【化３】

（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又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。）
【００６２】
【化４】
（II）式

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は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（II）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６３】
【化５】
（III）式

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は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（III）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６４】
【化６】
（IV）式

式中、Ｒ_１１，Ｒ_１２は置換もしくは無置換のアリール基、Ａｒ_７，Ａｒ_８，Ａｒ_９は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（IV）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６５】
【化７】
（Ｖ）式

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は同一又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、又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、（Ｉ）式の場合と同じである。なお、（Ｖ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６６】
【化８】
（VI）式

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は同一又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、（Ｉ）式の場合と同じである。なお、（VI）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６７】
【化９】
（VII）式

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は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（VII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６８】
【化１０】
（VIII）式

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は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（VIII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００６９】
【化１１】
（IＸ）式

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は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（IX）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００７０】
【化１２】
（Ｘ）式

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は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（Ｘ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でもよい。
【００７１】
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。
【００７２】
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。
【００７３】
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２００００−２０６７２３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。この場合にも、先の移動度を満足できるような材料が有効に使用できる。
【００７４】
本発明において電荷輸送層（４７）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。
【００７５】
結着樹脂としては、先に電荷輸送層（４７）で挙げた結着樹脂をそのまま用いるほかに、電荷発生層（４５）で挙げた結着樹脂を混合して用いてもよい。もちろん、先に挙げた高分子電荷輸送物質も良好に使用できる。結着樹脂１００重量部に対する電荷発生物質の量は５〜４０重量部が好ましく、電荷輸送物質の量は０〜１９０重量部が好ましく、さらに好ましくは５０〜１５０重量部である。単層感光層は、電荷発生物質、結着樹脂を必要ならば電荷輸送物質とともにテトラヒドロフラン、ジオキサン、ジクロロエタン、シクロヘキサン等の溶媒を用いて分散機等で分散した塗工液を、浸漬塗工法やスプレーコート、ビードコートなどで塗工して形成できる。単層感光層の膜厚は、５〜１００μｍ程度が適当である。
【００７６】
本発明の電子写真感光体には、導電性支持体（４１）と感光層との間に下引き層を設けることができる。下引き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剤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、下引き層にはモアレ防止、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。
【００７７】
これらの下引き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。更に本発明の下引き層として、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、本発明の下引き層には、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。下引き層の膜厚は０〜５μｍが適当である。
【００７８】
本発明の感光体においては、感光層保護の目的で、保護層（４９）が感光層の上に設けられることもある。保護層（４９）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。
【００７９】
保護層（４９）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−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。更に、この中でも六方ちょう密構造を有するα−アルミナが最も有効に使用できる。
【００８０】
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。
【００８１】
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。
【００８２】
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。
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。
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、系が酸性であった方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。
【００８３】
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。
【００８４】
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号公報の第１図、特開平５−１１３６８８号公報の第１図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４．０ｃｍ^２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。１０^６Ω・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の言うところの比抵抗値と定義するものである。
【００８５】
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。
【００８６】
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。これらフィラー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。
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、凝集体が少ない方が好ましい。
【００８７】
また、保護層（４９）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。ここで言う濃度とは、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。
保護層のフィラー以外の成分を高分子だけで構成することにより、機械的な耐摩耗性を向上させるだけでなく、化学的な安定性を高めることもできる。高分子は低分子に比べて化学的な反応性に乏しく、帯電部材から発生する酸化性ガスへの耐性、あるいは放電によるスパッタリング効果に対する耐性も高い。保護層のように耐摩耗性の高い膜を表面に有する場合、繰り返し使用での画像ボケの問題が非常に顕著になる。これは、感光体表面に、酸化性ガスの吸着や低抵抗物質の付着（吸着）が起こるためであると考えられるが、上述のようにフィラー及び高分子成分だけから構成される保護層を採用した場合には、吸着サイトが減少することになり、画像ボケに対して高い効果を示すものである。
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、以上の他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。
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、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。
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、画像領域の端の方に位置され、また使用される色も限定される。また、フルカラー機もタンデム方式のものが主流になりつつあり、印刷速度が非常に向上してきた。このため、ビジネス文書の出力も多くなってきており、例えば会社のロゴを使用したような書式（書面）を出力するケースも増えている。このような場合には、特定の箇所にだけ印字が行なわれるため、感光体使用の偏りは一段と大きくなる。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。
【００８８】
本発明においては感光層と保護層との間に中間層を設けることも可能である。中間層には、一般にバインダー樹脂を主成分として用いる。これら樹脂としては、ポリアミド、アルコール可溶性ナイロン、水溶性ポリビニルブチラール、ポリビニルブチラール、ポリビニルアルコールなどが挙げられる。中間層の形成法としては、前述のごとく通常の塗布法が採用される。なお、中間層の厚さは０．０５〜２μｍ程度が適当である。
【００８９】
次に、図面を用いて本発明の電子写真方法ならびに電子写真装置を詳しく説明する。
図６は、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り、下記するような変形例も本発明の範疇に属するものである。
図６において、感光体（２１）は導電性支持体上に、特定結晶型を有し、一次粒子の平均粒子サイズが０．２μｍ以下であるチタニルフタロシアニン結晶を含有する電荷発生層と電荷輸送層が設けられてなる。帯電部材（２３）、転写前チャージャー（２７）、転写チャージャー（３０）、分離チャージャー（３１）、クリーニング前チャージャー（３３）には、コロトロン、スコロトロン、固体帯電器（ソリッド・ステート・チャージャー）、帯電ローラーを始めとする公知の手段が用いられる。帯電部材は、感光体に対し接触もしくは近接配置したものが良好に用いられる。また、帯電部材により感光体に帯電を施す際、帯電部材に直流成分に交流成分を重畳した電界により感光体に帯電を与えることにより、帯電ムラを低減することが可能で効果的である。特に、タンデム型のフルカラー画像形成装置においては、モノクロ画像形成装置の場合に発生する帯電ムラによるハーフトーン画像の濃度ムラの問題に加え、カラーバランス（色再現性）の低下という大きな問題につながる。直流成分に交流成分を重畳することにより、前記問題点は大きく改善されるものであるが、交流成分の条件（周波数、ピーク間電圧）が大きすぎる場合には、感光体へのハザードが大きくなり、感光体の劣化を早めてしまう場合がある。このため、交流成分の重畳は必要最低限にとどめるべきである。
【００９０】
ここでいう接触方式の帯電部材とは、感光体表面に帯電部材の表面が接触するタイプのものであり、帯電ローラー、帯電ブレード、帯電ブラシの形状がある。中でも帯電ローラーや帯電ブラシが良好に使用される。
また、近接配置した帯電部材とは、感光体表面と帯電部材表面の間に２００μｍ以下の空隙（ギャップ）を有するように非接触状態で近接配置したタイプのものである。このギャップは、大きすぎた場合には帯電が不安定になりやすく、また小さすぎた場合には、感光体に残留したトナーが存在する場合に、帯電部材表面が汚染されてしまう可能性がある。したがって、ギャップは１０〜２００μｍ、好ましくは１０〜１００μｍの範囲が適当である。空隙の距離から、コロトロン、スコロトロンに代表される公知のチャージ・ワイヤータイプの帯電器、接触方式の帯電ローラー、帯電ブラシ、帯電ブレードなどの接触帯電部材とは区別されるものである。
【００９１】
本発明において使用される近接配置された帯電部材は、感光体表面との空隙を適切に制御できる機構のものであればいかなる形状のものでも良い。例えば、感光体の回転軸と帯電部材の回転軸を機械的に固定して、適正ギャップを有するような配置にすればよい。中でも、帯電ローラーの形状の帯電部材を用い、帯電部材の非画像形成部両端にギャップ形成部材を配置して、この部分のみを感光体表面に当接させ、画像形成領域を非接触配置させる、あるいは感光体非画像形成部両端ギャップ形成部材を配置して、この部分のみを帯電部材表面に当接させ、画像形成領域を非接触配置させる様な方法が、簡便な方法でギャップを安定して維持できる方法である。特に特開２００２−１４８９０４号公報、特開２００２−１４８９０５号公報に記載された方法は良好に使用できる。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図７に示す。
【００９２】
転写手段には、一般に上記の帯電器が使用できるが、図６に示されるように転写チャージャー（３０）と分離チャージャー（３１）を併用したものが効果的である。
また、画像露光部（２５）の光源にはＬＤもしくはＬＥＤが用いられる。除電ランプ（２２）等の光源には、蛍光灯、タングステンランプ、ハロゲンランプ、水銀灯、ナトリウム灯、発光ダイオード（ＬＥＤ）、半導体レーザー（ＬＤ）、エレクトロルミネッセンス（ＥＬ）などの発光物全般を用いることができる。そして、所望の波長域の光のみを照射するために、シャープカットフィルター、バンドパスフィルター、近赤外カットフィルター、ダイクロイックフィルター、干渉フィルター、色温度変換フィルターなどの各種フィルターを用いることもできる。
かかる光源等は、図６に示される工程の他に光照射を併用した転写工程、除電工程、クリーニング工程、あるいは前露光などの工程を設けることにより、感光体に光が照射される。
【００９３】
さて、現像ユニット（２６）により感光体（２１）上に現像されたトナーは、転写紙（２９）に転写されるが、全部が転写されるわけではなく、感光体（２１）上に残存するトナーも生ずる。このようなトナーは、ファーブラシ（３４）およびブレード（３５）により、感光体より除去される。クリーニングは、クリーニングブラシだけで行なわれることもあり、クリーニングブラシにはファーブラシ、マグファーブラシを始めとする公知のものが用いられる。
【００９４】
電子写真感光体に正（負）帯電を施し、画像露光を行なうと、感光体表面上には正（負）の静電潜像が形成される。これを負（正）極性のトナー（検電微粒子）で現像すれば、ポジ画像が得られるし、また正（負）極性のトナーで現像すれば、ネガ画像が得られる。
かかる現像手段には、公知の方法が適用されるし、また、除電手段にも公知の方法が用いられる。
【００９５】
図８には、本発明による電子写真プロセスの別の例を示す。感光体（６１）は導電性支持体上に、特定結晶型を有し、一次粒子の平均粒子サイズが０．２μｍ以下であるチタニルフタロシアニン結晶を含有する電荷発生層と電荷輸送層が設けられてなる。駆動ローラー（６２ａ），（６２ｂ）により駆動され、帯電器（６３）による帯電、光源（６４）による像露光、現像（図示せず）、帯電器（６５）を用いる転写、光源（６６）によるクリーニング前露光、ブラシ（６７）によるクリーニング、光源（６８）による除電が繰返し行なわれる。図８においては、感光体（６１）（勿論支持体が透光性である）に支持体側より画像露光の光照射が行なわれる。また、画像露光源（６４）は、ＬＤもしくはＬＥＤが好ましく用いられる。
【００９６】
以上の図示した電子写真プロセスは、本発明における実施形態を例示するものであって、もちろん他の実施形態も可能である。例えば、図８において感光層側よりクリーニング前露光を行なっているが、これは透光性支持体側から行なってもよいし、また、除電光の照射を支持体側から行なってもよい。
一方、光照射工程は、像露光、クリーニング前露光、除電露光が図示されているが、他に転写前露光、像露光のプレ露光、およびその他公知の光照射工程を設けて、感光体に光照射を行なうこともできる。
【００９７】
以上に示すような画像形成手段は、複写装置、ファクシミリ、プリンター内に固定して組み込まれていてもよいが、プロセスカートリッジの形でそれら装置内に組み込まれてもよい。プロセスカートリッジとは、感光体を内蔵し、他に帯電手段、露光手段、現像手段、転写手段、クリーニング手段、除電手段を含んだ１つの装置（部品）である。プロセスカートリッジの形状等は多く挙げられるが、一般的な例として、図９に示すものが挙げられる。感光体（７６）は導電性支持体上に、特定結晶型を有し、一次粒子の平均粒子サイズが０．２μｍ以下であるチタニルフタロシアニン結晶を含有する電荷発生層と電荷輸送層が設けられてなる。
【００９８】
図１０は、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り、下記するような変形例も本発明の範疇に属するものである。
図１０において、符号（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）はドラム状の感光体であり、この感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）は図中の矢印方向に回転し、その周りに少なくとも回転順に帯電部材（２Ｃ）、（２Ｍ）、（２Ｙ）及び（２Ｋ）、現像部材（４Ｃ）、（４Ｍ）、（４Ｙ）及び（４Ｋ）、クリーニング部材（５Ｃ）、（５Ｍ）、（５Ｙ）及び（５Ｋ）が配置されている。帯電部材（２Ｃ）、（２Ｍ）、（２Ｙ）及び（２Ｋ）は、感光体表面を均一に帯電するための帯電装置を構成する帯電部材である。この帯電部材（２Ｃ）、（２Ｍ）、（２Ｙ）及び（２Ｋ）と、現像部材（４Ｃ）、（４Ｍ）、（４Ｙ）及び（４Ｋ）の間の感光体表面に図示しない露光部材からのレーザー光（３Ｃ）、（３Ｍ）、（３Ｙ）及び（３Ｋ）が照射され、感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）に静電潜像が形成されるようになっている。そして、このような感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）を中心とした４つの画像形成要素（６Ｃ）、（６Ｍ）、（６Ｙ）及び（６Ｋ）が、転写材搬送手段である転写搬送ベルト（１０）に沿って並置されている。転写搬送ベルト（１０）は各画像形成ユニット（６Ｃ）、（６Ｍ）、（６Ｙ）及び（６Ｋ）の現像部材（４Ｃ）、（４Ｍ）、（４Ｙ）及び（４Ｋ）とクリーニング部材（５Ｃ）、（５Ｍ）、（５Ｙ）及び（５Ｋ）の間で感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）に当接しており、転写搬送ベルト（１０）の感光体側の裏側に当たる面（裏面）には転写バイアスを印加するための転写ブラシ（１１Ｃ）、（１１Ｍ）、（１１Ｙ）及び（１１Ｋ）が配置されている。各画像形成要素（６Ｃ）、（６Ｍ）、（６Ｙ）及び（６Ｋ）は現像装置内部のトナーの色が異なることであり、その他は全て同様の構成となっている。
【００９９】
図１０に示す構成のカラー電子写真装置において、画像形成動作は次のようにして行なわれる。まず、各画像形成要素（６Ｃ）、（６Ｍ）、（６Ｙ）及び（６Ｋ）において、感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）が矢印方向（感光体と連れ周り方向）に回転する帯電部材（２Ｃ）、（２Ｍ）、（２Ｙ）及び（２Ｋ）により帯電され、次に感光体の内側に配置された露光部（図示しない）でレーザー光（３Ｃ）、（３Ｍ）、（３Ｙ）及び（３Ｋ）により、作成する各色の画像に対応した静電潜像が形成される。次に現像部材（４Ｃ）、（４Ｍ）、（４Ｙ）及び（４Ｋ）により潜像を現像してトナー像が形成される。現像部材（４Ｃ）、（４Ｍ）、（４Ｙ）及び（４Ｋ）は、それぞれＣ（シアン）、Ｍ（マゼンタ）、Ｙ（イエロー）、Ｋ（ブラック）のトナーで現像を行なう現像部材で、４つの感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）上で作られた各色のトナー像は転写紙上で重ねられる。転写紙（７）は給紙コロ（８）によりトレイから送り出され、一対のレジストローラ（９）で一旦停止し、上記感光体上への画像形成とタイミングを合わせて転写搬送ベルト（１０）に送られる。転写搬送ベルト（１０）上に保持された転写紙（７）は搬送されて、各感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）との当接位置（転写部）で各色トナー像の転写が行なわれる。感光体上のトナー像は、転写ブラシ（１１Ｃ）、（１１Ｍ）、（１１Ｙ）及び（１１Ｋ）に印加された転写バイアスと感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）との電位差から形成される電界により、転写紙（７）上に転写される。そして４つの転写部を通過して４色のトナー像が重ねられた記録紙（７）は定着装置（１２）に搬送され、トナーが定着されて、図示しない排紙部に排紙される。また、転写部で転写されずに各感光体（１Ｃ）、（１Ｍ）、（１Ｙ）及び（１Ｋ）上に残った残留トナーは、クリーニング装置（５Ｃ）、（５Ｍ）、（５Ｙ）及び（５Ｋ）で回収される。なお、図１０の例では、画像形成要素は転写紙搬送方向上流側から下流側に向けてＣ（シアン）、Ｍ（マゼンタ）、Ｙ（イエロー）、Ｋ（ブラック）の色の順で並んでいるが、この順番に限るものではなく、色順は任意に設定されるものである。また、黒色のみの原稿を作成する際には、黒色以外の画像形成要素（６Ｃ）、（６Ｍ）、（６Ｙ）が停止するような機構を設けることは本発明に特に有効に利用できる。更に、図１０において帯電部材は感光体と当接しているが、両者の間に適当なギャップ（１０〜２００μｍ程度）を設けてやることにより、両者の摩耗量が低減できると共に、帯電部材へのトナーフィルミングが少なくて済み、良好に使用できる。
【０１００】
以上に示したような画像形成手段は、複写装置、ファクシミリ、プリンター内に固定して組み込まれていてもよいが、各々の電子写真要素はプロセスカートリッジの形でそれら装置内に組み込まれてもよい。プロセスカートリッジとは、感光体を内蔵し、他に帯電手段、露光手段、現像手段、転写手段、クリーニング手段、除電手段等を含んだ１つの装置（部品）である。
【０１０１】
【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、ブラッグ角２θの最大回折ピークが２７．２°±０．２°にある結晶型のチタニルフタロシアニン顔料の具体的な合成例を述べる。
（実施例１）
１，３−ジイミノイソインドリン２９２部とスルホラン１８００部を混合し、窒素気流下でチタニウムテトラブトキシド２０４部を滴下する。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。
得られた熱水洗浄処理した粗チタニルフタロシアニン顔料のうち６０部を９６％硫酸１０００部に３〜５℃下撹拌、溶解し、ろ過した。得られた硫酸溶液を氷水３５０００部中に撹拌しながら滴下し、析出した結晶を濾過、ついで洗浄液が中性になるまで水洗を繰り返し、チタニルフタロシアニン顔料の水ペーストを得た。
この水ペースト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９８部を得た。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７８部を得た。
更に、このチタニルフタロシアニン結晶３０ｇをテトラヒドロフラン３００ｇに浸漬し、２回目の結晶変換を行なった。１２時間浸漬放置した後、濾過分別し、上記と同じ条件で減圧乾燥を行ない、本発明のチタニルフタロシアニン結晶を得た。これを顔料１とする。
【０１０２】
（実施例２）
実施例１における２回目の結晶変換時間を１２時間から２４時間に変更した以外は、実施例１と同様に処理を行ない、本発明のチタニルフタロシアニン結晶を得た。これを顔料２とする。
【０１０３】
（実施例３）
実施例１における２回目の結晶変換溶媒をテトラヒドロフランから２−ブタノンに変更した以外は、実施例１と同様に処理を行ない、本発明のチタニルフタロシアニン結晶を得た。これを顔料３とする。
【０１０４】
（実施例４）
実施例１における２回目の結晶変換操作を下記の通りの条件に変更した以外は、実施例１と同様に処理を行ない、本発明のチタニルフタロシアニン結晶を得た。これを顔料４とする。
（２回目の結晶変換処理）
１回目の結晶変換処理を行なったチタニルフタロシアニン結晶３０ｇを、市販のミキサーにより機械的剪断力を５分間与えた後、粉末を取り出した。
【０１０５】
（実施例５）
実施例１における２回目の結晶変換操作を下記の通りの条件に変更した以外は、実施例１と同様に処理を行ない、本発明のチタニルフタロシアニン結晶を得た。これを顔料５とする。
（２回目の結晶変換処理）
１回目の結晶変換処理を行なったチタニルフタロシアニン結晶３０ｇを、２ｋｇのφ６ｍｍのジルコニアボールと共に、φ９０ｍｍのガラスポットに投入し、乾式ミリングを１０分間行なった後、粉末を取り出した。
【０１０６】
（比較例１）
実施例１におけるテトラヒドロフランによる結晶変換処理に際して、特開２００１−１８７７９４号公報に記載の合成例１の方法に準じて、結晶変換時間を４時間に設定した以外は実施例１と同様に処理し、チタニルフタロシアニン結晶を得た。これを顔料６とする。
【０１０７】
（比較例２）
実施例１において、テトラヒドロフランによる結晶変換処理に際して、特開２００１−１８７７９４号公報に記載の合成例１の方法に準じて、結晶変換時間を４時間に設定し、続いて一昼夜静置保管して、翌日濾過を行なった以外は、実施例１と同様に処理し、チタニルフタロシアニン結晶を得た。これを顔料７とする。
【０１０８】
（比較例３）
実施例１において、２回目の結晶変換処理を行なわない以外は、実施例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。これを顔料８とする。
【０１０９】
（比較例４）
実施例１において、１回目の結晶変換溶媒として、テトラヒドロフランの代わりに２−ブタノンを用い、２回目の結晶変換を行なわない以外は、実施例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。これを顔料９とする。
【０１１０】
実施例１で作製された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。
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実施例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。
【０１１１】
実施例１、比較例１〜２、４における１回目の結晶変換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、上記の水ペーストと同じ方法によりＴＥＭ観察を行なった。それぞれ、所定の結晶変換処理を行ない、濾過直前の液をサンプリングし、それぞれの結晶変換溶媒でおよそ１重量％になるように希釈し、測定に供した。求めた平均粒子サイズを表１に示す。
なお、実施例１、比較例１〜２、４で作製されたチタニルフタロシアニン結晶は、水ペーストとは異なり結晶の形が同一ではなかった（三角形に近い形、４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。
【０１１２】
【表１】

【０１１３】
実施例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。
上述のように得られた水ペーストの乾燥粉末と、実施例１〜５および比較例１〜４で得られたチタニルフタロシアニン結晶についてのＸ線回折スペクトルを以下に示す条件で測定した。
Ｘ線管球：Ｃｕ
電圧：４０ｋＶ
電流：２０ｍＡ
走査速度：１°／分
走査範囲：３°〜４０°
時定数：２秒
水ペーストの乾燥粉末のＸ線回折スペクトルを図１１に示す。
【０１１４】
実施例１〜５およびに比較例１〜２については、２６．３°のピーク強度以外は、いずれの場合にも同様のＸ線回折スペクトルを示したため、代表例として実施例２で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを図１２に示す。比較例３で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを図１３に示すが、２６．３°にピークを示さないものであった。比較例４で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを図１４に示すが、最低角が７．５°に存在するものであった。
【０１１５】
（比較例５）
特開平１−２９９８７４号公報に記載の方法に準じて顔料を作製した。すなわち、実施例１で作製したウェットケーキ（水ペースト）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１時間行なった。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。これを顔料１０とする。
【０１１６】
（比較例６）
特開平３−２６９０６４号公報に記載の方法に準じて顔料を作製した。すなわち、実施例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。これを顔料１１とする。
【０１１７】
（比較例７）
特開平２−８２５６号公報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、ついで１−クロロナフタレンで粉体が青色になるまで洗浄、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、乾燥し顔料を得た。これを顔料１２とする。
【０１１８】
（比較例８）
特開昭６４−１７０６６号公報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℃―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。これを顔料１３とする。
【０１１９】
（比較例９）
特開平１１−５９１９号公報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２１．３部を得た。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（含有フタロシアニン量２部と仮定して）をＴＨＦ１００部中で約５時間攪拌を行ない、ろ過、洗浄を行ない、乾燥して顔料を得た。これを顔料１４とする。
【０１２０】
比較例５〜９で作製した顔料は先ほどと同様の方法で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。以上の測定結果をまとめて表２に示す。尚、顔料４および５に関しては、２６．３°のピーク強度が小さかったため、先のＸ線回折測定の走査範囲を２５°〜３０°として、再測定を行ない、強度比を正確に求めた。
【０１２１】
【表２】

【０１２２】
（実施例６）
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（これを分散液１とする）。
実施例１で作製したチタニルフタロシアニン結晶（顔料１） 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。
【０１２３】
（実施例７）
実施例６におけるチタニルフタロシアニン結晶を、顔料２に変更した以外は、実施例６と同様に分散液を作製した（これを分散液２とする）。
【０１２４】
（実施例８）
実施例６におけるチタニルフタロシアニン結晶を、顔料３に変更した以外は、実施例６と同様に分散液を作製した（これを分散液３とする）。
【０１２５】
（実施例９）
実施例６におけるチタニルフタロシアニン結晶を、顔料４に変更した以外は、実施例６と同様に分散液を作製した（これを分散液４とする）。
【０１２６】
（実施例１０）
実施例６におけるチタニルフタロシアニン結晶を、顔料５に変更した以外は、実施例６と同様に分散液を作製した（これを分散液５とする）。
【０１２７】
（比較例１０）
実施例６におけるチタニルフタロシアニン結晶を、顔料６に変更した以外は、実施例６と同様に分散液を作製した（これを分散液６とする）。
【０１２８】
（比較例１１）
実施例６におけるチタニルフタロシアニン結晶を、顔料７に変更した以外は、実施例６と同様に分散液を作製した（これを分散液７とする）。
【０１２９】
（比較例１２）
実施例６におけるチタニルフタロシアニン結晶を、顔料８に変更した以外は、実施例６と同様に分散液を作製した（これを分散液８とする）。
【０１３０】
（比較例１３）
実施例６におけるチタニルフタロシアニン結晶を、顔料９に変更した以外は、実施例６と同様に分散液を作製した（これを分散液９とする）。
【０１３１】
（比較例１４）
実施例６におけるチタニルフタロシアニン結晶を、顔料１０に変更した以外は、実施例６と同様に分散液を作製した（これを分散液１０とする）。
【０１３２】
（比較例１５）
実施例６におけるチタニルフタロシアニン結晶を、顔料１１に変更した以外は、実施例６と同様に分散液を作製した（これを分散液１１とする）。
【０１３３】
（比較例１６）
実施例６におけるチタニルフタロシアニン結晶を、顔料１２に変更した以外は、実施例６と同様に分散液を作製した（これを分散液１２とする）。
【０１３４】
（比較例１７）
実施例６におけるチタニルフタロシアニン結晶を、顔料１３に変更した以外は、実施例６と同様に分散液を作製した（これを分散液１３とする）。
【０１３５】
（比較例１８）
実施例６におけるチタニルフタロシアニン結晶を、顔料１４に変更した以外は、実施例６と同様に分散液を作製した（これを分散液１４とする）。
【０１３６】
以上のように、実施例６〜１０および比較例１０〜１８で作製した分散液中の顔料粒子サイズ（体積平均粒径）を堀場製作所：ＣＡＰＡ７００にて測定した。結果を表３に示す。
また、作製した分散液を乾固し、粉末にしたものを前述と同様にＸ線回折スペクトルを測定したが、いずれの場合にも分散前と同じＸ線回折スペクトルを示した。
【０１３７】
【表３】

【０１３８】
（実施例１１）
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、０．２μｍの電荷発生層、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）。
◎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
先述の分散液１を用いた。
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
【０１３９】
【化１３】

塩化メチレン ８０部
【０１４０】
（実施例１２）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液２を用いた以外は、実施例１１と同様に感光体を作製した（感光体２とする）。
【０１４１】
（実施例１３）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液３を用いた以外は、実施例１１と同様に感光体を作製した（感光体３とする）。
【０１４２】
（実施例１４）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液４を用いた以外は、実施例１１と同様に感光体を作製した（感光体４とする）。
【０１４３】
（実施例１５）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液５を用いた以外は、実施例１１と同様に感光体を作製した（感光体５とする）。
【０１４４】
（比較例１９）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液６を用いた以外は、実施例１１と同様に感光体を作製した（感光体６とする）。
【０１４５】
（比較例２０）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液７を用いた以外は、実施例１１と同様に感光体を作製した（感光体７とする）。
【０１４６】
（比較例２１）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液８を用いた以外は、実施例１１と同様に感光体を作製した（感光体８とする）。
【０１４７】
（比較例２２）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液９を用いた以外は、実施例１１と同様に感光体を作製した（感光体９とする）。
【０１４８】
（比較例２３）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液１０を用いた以外は、実施例１１と同様に感光体を作製した（感光体１０とする）。
【０１４９】
（比較例２４）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液１１を用いた以外は、実施例１１と同様に感光体を作製した（感光体１１とする）。
【０１５０】
（比較例２５）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液１２を用いた以外は、実施例１１と同様に感光体を作製した（感光体１２とする）。
【０１５１】
（比較例２６）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液１３を用いた以外は、実施例１１と同様に感光体を作製した（感光体１３とする）。
【０１５２】
（比較例２７）
実施例１１における電荷発生層塗工液として、分散液１の代わりに分散液１４を用いた以外は、実施例１１と同様に感光体を作製した（感光体１４とする）。
【０１５３】
以上のように作製した実施例１０〜１５および比較例１９〜２７の電子写真感光体を図６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ーを用い、下記の帯電条件で画像を出力した（評価環境は、２３゜Ｃ−５５％ＲＨ、１０゜Ｃ−１５％ＲＨ、３０゜Ｃ−９０％ＲＨの３環境でそれぞれ行なった）。
帯電条件：
ＤＣバイアス：約−１５７０Ｖ（ランニング試験前の感光体表面の未露光部電位が、−９００Ｖになるように設定）
書き込み率６％のチャートを用い、連続して２００００枚の印刷を行ない、初期及び２００００枚後の画像を評価した。画像評価は、初期及び２００００枚後に白ベタ画像を出力し、地肌汚れの評価を行なった（下記ランクで評価した）。また、同時に、現像部位置における感光体の表面電位（未露光部）を測定するために、現像器が装着される位置に電位計がセットできるような治具を用いて、初期及び２００００枚の画像出力後の感光体表面電位を測定した。以上の結果を表４に示す。
【０１５４】
【表４−１】
２３℃−５５％ＲＨ環境下での評価

【０１５５】
【表４−２】
１０℃−１５％ＲＨ環境下での評価

【０１５６】
【表４−３】
３０℃−９０％ＲＨ環境下での評価

地汚れランク：
５：地汚れほとんどなし、
４：わずかにあり、
３：実使用限界レベル、
２以下：実使用には耐えないレベル
【０１５７】
（実施例１６）
実施例１４における電荷輸送層塗工液を下記組成のものに変更した以外は、実施例１４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）
【０１５８】
【化１４】

下記構造の添加剤 ０．５部
【０１５９】
【化１５】

塩化メチレン １００部
【０１６０】
（実施例１７）
実施例１４における電荷輸送層の膜厚を２１μｍ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、４μｍの保護層を設けた以外は実施例１４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
【０１６１】
【化１６】

α−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
【０１６２】
（実施例１８）
実施例１４における電荷輸送層の膜厚を２１μｍ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、４μｍの保護層を設けた以外は実施例１４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
【０１６３】
【化１７】

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）
シクロヘキサノン ５００部
テトラヒドロフラン １５０部
【０１６４】
（実施例１９）
実施例１４における電荷輸送層の膜厚を２１μｍ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、４μｍの保護層を設けた以外は実施例１４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
【０１６５】
【化１８】

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）
シクロヘキサノン ５００部
テトラヒドロフラン １５０部
【０１６６】
（実施例２０）
実施例１４における電荷輸送層の膜厚を２１μｍ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、４μｍの保護層を設けた以外は実施例１４と同様に感光体を作製した。
◎保護層塗工液
下記構造式の高分子電荷輸送物質 １７部
（重量平均分子量：約１３５０００）
【０１６７】
【化１９】

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
【０１６８】
以上のように作製した実施例１６〜２０の電子写真感光体を、実施例１４の感光体と共に、図６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ーを用い、下記の帯電条件で画像を出力した。
帯電条件：
ＤＣバイアス：−１６００Ｖ（感光体表面の未露光部電位が−９００Ｖになるように設定）
書き込み率６％のチャートを用い、連続して５００００枚の印刷を行ない、初期及び５００００枚後の画像を評価した。画像評価は、初期及び５００００枚後に白ベタ画像を出力し、地肌汚れの評価を行なった（下記ランクで評価した）。
また、５００００枚出力後、３０゜Ｃ−９０％ＲＨの環境下で画像を５０枚出力した。
更に、５００００枚出力における感光体表面の摩耗量を測定した。以上の結果を表５に示す。
【０１６９】
【表５】

地汚れランク：
５：地汚れほとんどなし、
４：わずかにあり、
３：実使用限界レベル、
２以下：実使用には耐えないレベル
【０１７０】
（実施例２１）
実施例１４で作製した感光体を用い、先の図３に示す図６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、帯電部材として図７に示すような帯電ローラーの両端部に厚さ６０μｍ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６０μｍ）を用い、下記の帯電条件で画像を出力した。
帯電条件：
ＤＣバイアス：約−１６２０Ｖ（感光体表面の未露光部電位が−９００Ｖになるように設定）
書き込み率６％のチャートを用い、連続して２００００枚の印刷を行ない、初期及び２００００枚後の画像を評価した。２００００枚後にハーフトーン画像を出力して評価を行なった。
【０１７１】
（実施例２２）
実施例２１で実施した評価を、以下のように帯電条件を変更して行なった。
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
【０１７２】
（実施例２３）
実施例２２において、絶縁テープの厚みを変えて、空隙を１６０μｍに変更した以外は実施例２２と同様に評価を行なった。
【０１７３】
（実施例２４）
実施例２３において、絶縁テープの厚みを変えて、空隙を２４０μｍに変更した以外は実施例２２と同様に評価を行なった。
以上の結果を実施例１４の場合と合わせて表６に示す。
【０１７４】
【表６】

【０１７５】
（実施例２５）
実施例１４において使用した支持体を、直径３０ｍｍのアルミニウムシリンダー（ＪＩＳ１０５０）に変更した以外は実施例１４と同様に感光体を作製した。
【０１７６】
（実施例２６）
実施例２５において、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、実施例２５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、６μｍの陽極酸化皮膜が形成された支持体を得た。
【０１７７】
（比較例２８）
比較例１９において使用した支持体を、直径３０ｍｍのアルミニウムシリンダー（ＪＩＳ１０５０）に変更した以外は比較例１９と同様に感光体を作製した。
【０１７８】
（比較例２９）
比較例２１において使用した支持体を、直径３０ｍｍのアルミニウムシリンダー（ＪＩＳ１０５０）に変更した以外は比較例２１と同様に感光体を作製した。
【０１７９】
以上のように作製した実施例２５〜２６および比較例２８〜２９の感光体を、図９に示すような電子写真装置用カートリッジに装着し、図１０に示す画像形成装置に搭載し（すべての画像形成要素に同じ感光体を搭載した）、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、帯電部材として図４に示すような帯電ローラーの両端部に厚さ６０μｍ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６０μｍ）を用い、下記の帯電条件で画像を出力した。
帯電条件：
ＤＣバイアス：−８００Ｖ
ＡＣバイアス：２．０ｋＶ（peak to peak）、周波数：１．８ｋＨｚ
【０１８０】
試験環境３０℃−９０％ＲＨ下で、書き込み率６％のフルカラーチャートを用い、連続して１００００枚の印刷を行ない、初期及び１００００枚後の画像を評価した。画像評価は、初期及び１００００枚後に白ベタ画像を出力し、地肌汚れの評価を行なった。また、色再現性を評価するチャートにて、１００００枚後の色再現性を評価した。結果を表７に示す。
【０１８１】
【表７】

地汚れランク：
５：地汚れほとんどなし、
４：わずかにあり、
３：実使用限界レベル、
２以下：実使用には耐えないレベル
【０１８２】
最後に、本発明のチタニルフタロシアニン結晶の特徴であるブラッグ角２θ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。
【０１８３】
測定例１
先の実施例１の１回目の結晶変換で得た顔料（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、先ほどと同様に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１５に示す。
【０１８４】
測定例２
先の比較例４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、先ほどと同様に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１６に示す。
【０１８５】
図１５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分かる。一方、図１６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１５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分かる。
【０１８６】
【発明の効果】
以上、詳細且つ具体的な説明より明らかなように、本発明によれば、分散液作製にあたり結晶型を変えることなく（結晶安定性の高い）分散可能な有機顔料を作製する方法が提供される。これを用いることにより、特定の結晶型を維持したまま、粒径の細かい分散液が提供される。この分散液は、電子写真感光体用分散液として非常に有用であり、特定の感光体特性を与え、かつ塗膜欠陥の少ない感光体を作製することが可能である。これにより、各種環境下においても静電特性が安定であり、耐摩耗性の高い感光体が提供される。更に、高感度を失うことなく繰り返し使用によっても帯電性の低下の少ない安定な電子写真装置および電子写真装置用プロセスカートリッジが提供される。
【図面の簡単な説明】
【図１】本発明の好ましい不定形チタニルフタロシアニンの粒子状態を表わす電子顕微鏡写真である。
【図２】本発明の結晶変換後のチタニルフタロシアニンの電子顕微鏡写真である。
【図３】本発明の結晶変換後のチタニルフタロシアニンの他の電子顕微鏡写真である。
【図４】本発明に用いられる電子写真感光体の構成例を示す断面図である。
【図５】本発明に用いられる電子写真感光体の他の構成例を示す断面図である。
【図６】本発明の電子写真プロセス及び電子写真装置を説明するための概略図である。
【図７】近接帯電機構を示す概略図（ギャップ保持機構が帯電部材側に形成されている）である。
【図８】本発明の電子写真プロセスの他の例を示す概略図である。
【図９】本発明の電子写真プロセスカートリッジの一例を示す概略図である。
【図１０】本発明のタンデム式フルカラー電子写真装置を説明するための他の概略図である。
【図１１】水ペーストの乾燥粉末のＸ線回折スペクトルを示す図である。
【図１２】実施例２で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを示す図である。
【図１３】比較例３で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを示す図である。
【図１４】比較例４で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを示す図である。
【図１５】測定例１で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを示す図である。
【図１６】測定例２で得られたチタニルフタロシアニン結晶のＸ線回折スペクトルを示す図である。
【符号の説明】
１Ｃ、１Ｍ、１Ｙ、１Ｋ………ドラム状感光体
２Ｃ、２Ｍ、２Ｙ、２Ｋ………帯電部材
３Ｃ、３Ｍ、３Ｙ、３Ｋ………レーザー光
４Ｃ、４Ｍ、４Ｙ、４Ｋ………現像部材
５Ｃ、５Ｍ、５Ｙ、５Ｋ………クリーニング部材
６Ｃ、６Ｍ、６Ｙ、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
１１Ｃ、１１Ｍ、１１Ｙ、１１Ｋ………転写ブラシ
１２………定着装置
２１………感光体
２２………除電ランプ
２３………帯電部材
２５………画像露光部
２６………現像ユニット
２７………転写前チャージャ
２８………レジストローラ
２９………転写紙
３０………転写チャージャ
３１………分離チャージャ
３２………分離爪
３３………クリーニング前チャージャ
３４………ファーブラシ
３５………ブレード
４１………導電性支持体
４５………電荷発生層
４７………電荷輸送層
４９………保護層
５０………感光体
５１………帯電ローラー
５２………ギャップ形成部材
５３………金属シャフト
５４………画像形成領域
５５………非画像形成領域
６１………感光体
６２ａ………駆動ローラ
６２ｂ………駆動ローラ
６３………帯電チャージャ
６４………像露光源
６５………転写チャージャ
６６………クリーニング前露光
６７………クリーニングブラシ
６８………除電光源
７６………感光体
７７………帯電チャージャ
７８………クリーニングブラシ
７９………画像露光部
８０………現像ローラ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a titanyl phthalocyanine crystal, a method for producing a titanyl phthalocyanine crystal, an electrophotographic photoreceptor produced using the same, an electrophotographic method using the electrophotographic photoreceptor, an electrophotographic apparatus, and a process cartridge for an electrophotographic apparatus About. Specifically, titanyl phthalocyanine crystals with excellent dispersibility and crystal stability and good handleability, a simple and stable production method of the above-mentioned titanyl phthalocyanine crystals, and the stability of the charging potential and residual potential of the photoreceptor even after repeated use The present invention relates to an electrophotographic photosensitive member that is excellent in the occurrence of abnormal images such as soiling, an electrophotographic method using the same, an electrophotographic apparatus, and a process cartridge for an electrophotographic apparatus.
[0002]
[Prior art]
Organic pigments have been used as paint fillers for a relatively long time. In particular, the richness of the color is an advantage not found in inorganic pigments. In recent years, as an application example of organic pigments, various materials have been produced since they have been spotlighted as materials for organic photoelectric conversion devices.
In forming such a film containing an organic pigment, most of the wet film forming methods that can easily increase the area are occupied. It is no exaggeration to say that the quality of a coating film formed by a wet film formation method is almost dependent on the quality of a dispersion containing a pigment. The quality of the dispersion is determined by the dispersibility of the pigment. Therefore, a good dispersion is one in which the pigment is sufficiently dispersed in the vehicle and the dispersion state continues for a long time.
[0003]
As a recent electrophotographic system, a digital system is mainly used, and negative / positive development (reversal development) is mainly used. In the case of negative / positive development, the potential of the portion where optical writing has been performed on the photosensitive member used in the electrophotographic system is attenuated, whereby the toner is developed in this portion and an image is formed. This is performed in consideration of the life of the light source and the light fatigue of the photosensitive member since the writing rate of the original is about 10% at most. However, if the background portion of the output document corresponds to an unexposed portion (high potential portion) of the photoreceptor, and the photosensitive layer (especially the charge generation layer) has a coating film defect or the like, the potential is originally maintained. The potential background portion (white background) attenuates the potential, and as a result, a point defect (background stain, black spot, etc.) that does not exist in the background portion of the input document may occur. This defect may be mistaken for a point in the drawing, a period in the English manuscript, a comma, etc., and can be said to be a fatal defect for an image. Such point defects are often derived from a layer composed of a dispersion film of pigment or the like. Therefore, in order to reduce such point defects, it is necessary to prepare a dispersion having good dispersibility of pigments and the like. At this time, the pigment particle size in the dispersion is preferably as fine as possible. However, if the primary particle size is approximately 0.2 μm or less, the above point defects are considerably reduced.
[0004]
In order to prepare such a dispersion liquid, various dispersion machines / dispersion systems and methods for increasing the dispersion efficiency have been proposed so far, and the dispersion liquid to be prepared using the synthesized pigment particles having a large average size. Techniques have been proposed for making the pigment particles therein as fine as possible (reducing the particle size) (see, for example, Patent Documents 1 to 14).
These dispersion techniques are excellent techniques in terms of how efficiently they are dispersed up to the primary particle size of the pigment used in preparing the dispersion. However, it is extremely difficult to make the particle size smaller than the primary particle size, and it is no exaggeration to say that the limit of the particle size in the dispersion is basically determined by the primary particle size of the pigment used. Some include those that crush the primary particles themselves by applying enormous energy, but these break the crystals themselves, so that there are problems as described later (for example, a decrease in dispersion efficiency, Crystal type transition, etc.).
[0005]
On the other hand, titanyl phthalocyanine is known as a useful charge generating material for an electrophotographic photoreceptor. This titanyl phthalocyanine is a polymorphic pigment having a large number of crystal forms as an aggregate even if represented by the same structural formula. In particular, a titanyl phthalocyanine crystal having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα is a polymorphic crystal form. Among them, specifically, it exhibits extremely high photocarrier generation efficiency as a charge generation material for an electrophotographic photosensitive member. However, since it is in a metastable state as a crystal state, it easily transitions to another crystal type. When excessive energy is applied to this crystal, it is likely to undergo a crystal transition to a titanyl phthalocyanine crystal having a maximum diffraction peak at 26.3 ° as a diffraction peak with a Bragg angle 2θ. Since this crystal has a much lower carrier generation efficiency than the previous crystal, even if only a part of the crystal is transferred, if this is used as a charge generating material for a photoreceptor, the photosensitivity decreases and the residual potential increases during repeated use. A problem occurs.
[0006]
On the other hand, if the dispersion condition is mild to prevent this crystal transition, a dispersion having a large average particle diameter is produced as described above, or a dispersion having coarse particles remaining is produced. When a dispersion liquid having a large average particle size is used in this way, the surface area of the charge generation material particles is reduced, and it becomes difficult to transfer charges with the charge transport material, resulting in a decrease in photosensitivity and repeated use. This causes a problem such as an increase in residual potential. Further, when coarse particles remain, problems such as background contamination and black spots in negative / positive development occur.
Thus, in the dispersion of titanyl phthalocyanine pigment particles, there is a trade-off relationship between the stability of the crystal form and the refinement of the particles, and there has been no means for simply solving this.
[0007]
As another approach for reducing the particle size of the pigment in the dispersion, a method of using a pigment that is easily dispersed, that is, a pigment having extremely small primary particles can be considered. In this method, primary particles of the pigment to be used are synthesized in advance so as to obtain a dispersion having a small particle size without giving excessive energy during dispersion. This method is considered to be an extremely effective method not only for improving the dispersion efficiency but also for using a pigment that easily undergoes crystal transition such as the above-mentioned titanyl phthalocyanine.
[0008]
However, there has been almost no approach from the viewpoint of pigment synthesis so far, but as the only similar technique, a method of preparing a dispersion using a means that uses a dispersing means simultaneously with crystal conversion has been proposed (for example, , See Patent Document 15). Certainly, according to this method, it is possible to form a dispersion of the primary particle size of the pigment formed by crystal conversion, but considering that the dispersion is subsequently used as a coating liquid, the crystal conversion solvent It is not necessarily an optimal coating solvent, and has the drawback of having limitations in coating. Moreover, since it cannot be stored as a pigment powder, storage restrictions are also imposed.
From the above, in order to produce a dispersion having a small average particle size without crystal transition of a titanyl phthalocyanine crystal that is extremely useful as a charge generation material for an electrophotographic photosensitive member, a titanyl phthalocyanine crystal having a small primary particle size and its Development of a manufacturing method was eagerly desired.
[0009]
On the other hand, a crystal having a maximum diffraction peak at 26.2 ° is stable as a crystal, has little environmental fluctuations in photoreceptor characteristics such as photosensitivity, and has good charging stability during repeated use. When a crystal having the maximum diffraction peak at 26.2 ° is mixed in a large amount with respect to the crystal having the maximum diffraction peak at 27.2 °, there is a large adverse effect on the characteristics of the photoreceptor, but a slight specific amount In the case where it exists only in some cases, the environmental stability and the chargeability in repeated use may be stabilized.
Control of this specific amount is an extremely important factor, but it is extremely difficult to control this amount (ratio) at the time of preparing the dispersion. Therefore, it has been found that a specific crystal type titanyl phthalocyanine crystal having a fine primary particle size is synthesized in advance, and the dispersion can be stably produced by using a dispersion means that does not change the crystal type.
[0010]
[Patent Document 1]
JP-A-4-337362
[Patent Document 2]
Japanese Patent Laid-Open No. 5-188614
[Patent Document 3]
JP-A-7-289870
[Patent Document 4]
JP-A-8-44086
[Patent Document 5]
JP-A-8-123045
[Patent Document 6]
JP-A-8-272111
[Patent Document 7]
JP-A-9-21873
[Patent Document 8]
JP-A-11-30871
[Patent Document 9]
Japanese Patent Laid-Open No. 11-258827
[Patent Document 10]
JP 2000-126638 A
[Patent Document 11]
JP 2000-181104 A
[Patent Document 12]
JP 2000-289311 A
[Patent Document 13]
JP 2001-265027 A
[Patent Document 14]
JP 2001-290292 A
[Patent Document 15]
JP 2000-239556 A
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide a titanyl phthalocyanine crystal having extremely small primary particles and a method for producing the same. Another object of the present invention is to provide a titanyl phthalocyanine crystal having a high crystal stability and a small particle size when producing a dispersion using the titanyl phthalocyanine pigment, and a method for producing the same.
Another object of the present invention is to provide a stable electrophotographic photosensitive member that does not cause deterioration in chargeability and increase in residual potential even after repeated use without losing high sensitivity. Another object of the present invention is to provide an electrophotographic photosensitive member that is less likely to cause abnormal images even when used repeatedly.
Still another object of the present invention is to provide a stable electrophotographic method, an electrophotographic apparatus, and a process cartridge for an electrophotographic apparatus that are capable of high-speed printing, are less dependent on the environment, and are less likely to cause abnormal images. .
[0012]
[Means for Solving the Problems]
In an electrophotographic photoreceptor using an organic pigment as a charge generation material, various characteristics are affected by the size of the charge generation material particles in the photosensitive layer. For example, in the photocarrier generation process, if the charge generation material particle size is large, the probability of deactivation of the photocarrier inside the particle increases before the photocarrier generated by the charge generation material is transferred to the charge transport material. . In addition, when the pigment particles are large, the surface area is inevitably reduced, and the amount of contact between the charge generation material and the charge transport material is reduced, and the carrier injection efficiency is reduced when the photocarrier is transferred to the charge transport material. Furthermore, if the charge generation material particles are large, the probability of a coating film defect in the photosensitive layer (charge generation layer) increases, and there is a problem that image defects are likely to occur.
For these reasons, it is desired to reduce the particle size of the charge generation material in the photosensitive layer (charge generation layer) as much as possible. Since the photosensitive layer (charge generation layer) is usually formed by a wet coating method, in order to reduce the particle size of the charge generation material in the photosensitive layer, the particle size of the charge generation material in the coating dispersion forming the photosensitive layer is reduced. Need to be small.
In order to reduce the size of the charge generation material particles in the dispersion for coating the photosensitive layer in this way, various dispersion methods have been proposed. All of them are secondary particles having an aggregate structure of charge generation materials. The major issue is how to pulverize and disperse the particles into primary particles. In these methods, by increasing the dispersion energy, extending the dispersion time, etc., it has been devised to be as close to the primary particles as possible, but the primary particle size is determined at the stage of charge generation material synthesis, In a normal method, it is difficult to make the particles smaller than the primary particle size.
[0013]
On the other hand, a dispersion method capable of giving stronger dispersion energy than a method such as ball milling that has been used for a long time has been proposed, and a method for further breaking up primary particles has been developed in recent years. In such a case, even if the primary particles are somewhat large, the crystal itself is pulverized by enormous dispersion energy, thereby reducing the particle size of the charge generation material. Such a system can be said to be very suitable for a material having high crystal stability of the charge generation material to be used.
[0014]
However, in the case of organic charge generating materials, there are many cases where only a specific crystal form exhibits a specific function even if it is a material represented by the same chemical structural formula. Such a specific crystal type may easily change due to simple physical / mechanical stress in addition to chemical stress. When using such a material, as described above, giving excessive dispersion energy that pulverizes the primary particles themselves changes the crystal form prior to the action of pulverizing the particles. Will happen. As a result, there are many cases in which a material that exhibits a specific function is changed to a material that does not exhibit its function sufficiently.
[0015]
The phthalocyanine crystal, particularly the titanyl phthalocyanine crystal used in the present invention is a polymorphic material, and the crystal form with particularly high photocarrier generation efficiency has a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα. Only the crystal having the maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °), and other crystal-type materials have a function as a charge generation material, but the current electrophotographic process Therefore, it does not have the characteristics satisfying the high speed, the small diameter of the photoreceptor, and the high stability upon repeated use. Therefore, it can be said that the crystal form is a specific crystal form.
[0016]
However, this titanyl phthalocyanine crystal having a maximum diffraction peak at least 27.2 ° is a metastable state as a titanyl phthalocyanine crystal and is a material having low crystal stability. Therefore, excessively applying the mechanical and physical stress as described above causes the crystal to be transferred to another crystal type which is a stable crystal type.
In this way, it is a titanyl phthalocyanine crystal that has a high function as a charge generation material. However, when it is applied to an electrophotographic photosensitive member, there is a trade-off relationship between particle miniaturization and crystal stability. There was no way to solve this easily.
[0017]
In order to solve the problems as described above, the present inventors tried to analyze the process of crushing and dispersing titanyl phthalocyanine crystals, and obtained the following knowledge.
That is, in the step of dispersing the titanyl phthalocyanine crystal, when dispersing to the target particle size, primary particles larger than the target particle size are present, so that an excessive dispersion energy must be given. In addition, there is a significant difference between the energy required to disperse secondary particles, which are aggregates of primary particles, to the primary particles and the energy required to further pulverize the primary particles. In the former, the force applied to the crystal is given to the dispersion itself, and crystal transition does not occur. In the latter, the applied energy acts on the grinding and at the same time the crystal transition proceeds.
From the above, the present inventors have made the primary particles of titanyl phthalocyanine crystal to be dispersed as fine as possible, so that the particle size is fine and crystal stability without giving excessive dispersion energy. It was found that a high dispersion liquid can be produced.
[0018]
The average particle size of the titanyl phthalocyanine crystal primary particles in the present invention is defined as follows.
The liquid containing the crystallized titanyl phthalocyanine crystal was observed with a transmission electron microscope (TEM), the obtained TEM image was taken as a TEM photograph, and 30 projected titanyl phthalocyanine crystals were arbitrarily selected. Measure the size of the major axis. An arithmetic average of the major diameters of the measured 30 individuals is obtained and set as an average particle size.
[0019]
Next, the present inventors tried an approach from the synthesis of titanyl phthalocyanine crystal and obtained the following knowledge.
That is, a titanyl phthalocyanine crystal having a maximum diffraction peak at least 27.2 ° is generally synthesized from titanyl phthalocyanine having a crystal stability lower than that. As a commonly used technique, crude titanyl phthalocyanine (or low crystallinity), which is thought to have the lowest crystal stability, is obtained by using a method called acid paste treatment with sulfuric acid or the like. Titanyl phthalocyanine). This is crystal-converted by various methods to obtain a titanyl phthalocyanine crystal having the target crystal type. In this crystal transformation, the most frequently used method is a method of crystal transition with an appropriate organic solvent in the presence of water.
[0020]
The present inventors paid attention to the morphology of titanyl phthalocyanine crystal particles before and after this crystal conversion. The particle size of the amorphous titanyl phthalocyanine (or low crystalline titanyl phthalocyanine) after the acid paste treatment described above is precipitated from the acid solution state of titanyl phthalocyanine in water with low solubility, and the primary particle size is It is a small one. Although depending on the conditions of the acid paste treatment, fine particles (shape close to needles) of about 0.1 μm or less are usually formed (see FIG. 1). Subsequently, the titanyl phthalocyanine crystal subjected to the crystal conversion treatment grows simultaneously with the crystal transition. Usually, after crystal conversion is performed more reliably, the crystal is separated and filtered. The primary particles are considerably large (about 0.3 to 0.4 μm, and about 1 μm if large) (see FIG. 2). From the above, it was found that the primary particle size of the titanyl phthalocyanine crystal used in the present invention was determined by this crystal conversion step.
[0021]
A titanyl phthalocyanine crystal having a specific crystal type used in the present invention is disclosed in JP-A-2001-187794. However, when a titanyl phthalocyanine crystal is produced under the conditions disclosed in this publication, a crystal having a large primary particle can be obtained as described above, which has the above-described problems.
As described above, the method of eliminating the relationship between the finer particle size and the trade-off between the crystal stability in the dispersion of the titanyl phthalocyanine crystal, which has been regarded as a problem so far, is to synthesize the primary particles of the titanyl phthalocyanine crystal to be used as follows. It will be.
As a result of examination in view of this point, as a result of using amorphous titanyl phthalocyanine (or low-crystalline titanyl phthalocyanine), which is the fine particle, as a raw material, and performing crystal conversion with an organic solvent in the presence of water, crystals can be obtained as much as possible. The conversion time is set short (subject to the crystal conversion conditions, but generally less than 1 hour, preferably less than 30 minutes). Before crystal growth occurs, separation and filtration are performed from the organic solvent, and the desired crystals are taken out. Thus, it was found that fine crystals of primary particles can be obtained (see FIG. 3).
[0022]
However, the above-mentioned problem is that the maximum diffraction peak is at least 27.2 ° as the diffraction peak (± 0.2 °) of the Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. In addition, it has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as a diffraction peak at the lowest angle side and By a titanyl phthalocyanine crystal having no peak between the peak and the peak at 9.4 ° and having a peak at 26.3 °, and the average primary particle size is 0.2 μm or less ” Solved.
In addition, the above problem is 2 ) “A diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα has a maximum diffraction peak of at least 7.0 to 7.5 °. In the presence of water, amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having a half-width of 1 ° or more and an average size of primary particles of 0.1 μm or less, One kind selected from tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, 1,1,2-trichloroethane Before carrying out crystal conversion with an organic solvent and growing the average size of primary particles after crystal conversion to 0.2 μm or more, Said The titanyl phthalocyanine after crystal conversion from an organic solvent is separated, filtered, dried, and then further subjected to crystal conversion treatment. In terms The manufacturing method of the titanyl phthalocyanine crystal of description ", ( 3 ) “The second crystal conversion process is One kind selected from toluene, xylene, acetone, 2-butanone, methylene chloride, chloroform, tetrahydrofuran The above-mentioned (( 2 ) Method for producing a titanyl phthalocyanine crystal according to item ", ( 4 ) “The second crystal conversion treatment is a treatment in which mechanical shearing force is applied. 2 The method for producing a titanyl phthalocyanine crystal according to the item) is solved.
In addition, the above problem is 5 ) “In an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are laminated on a conductive support, the charge generation layer includes the first (1) In terms An electrophotographic photosensitive member comprising the titanyl phthalocyanine crystal according to the description ", ( 6 ) “The charge transport layer contains a polymer charge transport material, 5 Electrophotographic photosensitive member according to item), ( 7 ) “The above-mentioned (characterized in that a protective layer is laminated on the charge transport layer” 6 Electrophotographic photosensitive member according to item), ( 8 ) "Resistivity 10 in the protective layer ¹⁰ It contains an inorganic pigment or metal oxide of Ω · cm or more. 7 Electrophotographic photosensitive member according to item), ( 9 ) “The metal oxide has a specific resistance of 10 ¹⁰ It is any one of alumina, titanium oxide, and silica having an Ω · cm or more. 8 Electrophotographic photosensitive member according to item), ( 10 ) “The metal oxide has a specific resistance of 10 ¹⁰ Α-alumina of Ω · cm or more, 9 Electrophotographic photosensitive member according to item), ( 11 ) “The protective layer contains a polymer charge transport material ( 6 ) To ( 10 The electrophotographic photosensitive member according to any one of the items], ( 12 ) “The electrophotographic photosensitive member is characterized in that the surface of the conductive support is anodized. 5 ) To ( 11 This is solved by the electrophotographic photosensitive member according to any one of the items).
In addition, the above problem is 13 ) “In an image forming method in which at least charging, image exposure, development and transfer are repeated on an electrophotographic photosensitive member, the electrophotographic photosensitive member is 5 ) To ( 12 This is solved by an image forming method characterized in that it is an electrophotographic photosensitive member according to any one of items 1).
In addition, the above problem is 14 ) “An image forming apparatus comprising an image forming element comprising at least a charging means, an image exposing means, a developing means, a transferring means and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the above ( 5 ) To ( 12 An image forming apparatus characterized in that it is an electrophotographic photosensitive member according to any one of Items 15 ) “The above-mentioned (( 14 Image forming apparatus according to item), ( 16 ) “The charging means is a device in which a charging member is placed in contact with or close to a photosensitive member ( 14 ) Or item ( 15 Image forming apparatus according to item), ( 17 ) “The gap between the charging member and the photosensitive member is 200 μm or less. 16 Image forming apparatus according to item), ( 18 ) “The charging means is characterized in that an alternating current component is superimposed on a direct current component so as to charge the photosensitive member. 16 ) Or item ( 17 This is solved by the image forming apparatus described in the item (1).
In addition, the above problem is 19 ) “A process cartridge for an image forming apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the first ( 5 ) To ( 12 This is solved by a process cartridge for an image forming apparatus, which is an electrophotographic photosensitive member according to any one of the above items.
[0023]
A specific method is described below.
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 “Phthalocyanine Compounds” (1963), “The Phthalocyanines” (1983) by Moser et al., JP-A-6-293769, and the like.
For example, as a first method, a mixture of phthalic anhydrides, metal or 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 in combination as necessary. As a second method, phthalonitriles and metal halides 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, such as aluminum phthalocyanines, indium phthalocyanines, oxovanadium phthalocyanines, oxotitanium phthalocyanines, zirconium phthalocyanines, and the like. The third method is to first react phthalic anhydride or phthalonitrile with ammonia to produce an intermediate such as 1,3-diiminoisoindoline, and then react with a metal halide in a high boiling solvent. It is a method to make it. The fourth method is a method in which phthalonitriles and a metal alkoxide are reacted 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 as a method for synthesizing an electrophotographic material.
[0024]
Next, a method for synthesizing amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) will be described. In this method, phthalocyanines are dissolved in sulfuric acid, diluted with water and reprecipitated, and an acid paste method or an acid slurry method can be used.
As a specific method, the above synthetic crude product is dissolved in 10-50 times the amount of concentrated sulfuric acid, and if necessary, insoluble matter is removed by filtration or the like, and this is sufficiently cooled to 10-50 times the amount of sulfuric acid. Slowly throw it into water or ice water to reprecipitate titanyl phthalocyanine. The precipitated titanyl phthalocyanine is filtered, washed with ion-exchanged water and filtered, 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 content concentration of about 5 to 15 wt%. What was produced in this way was the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) used in the present invention. In this case, the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) is at least 7.0 to 7 as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα. It is preferable to have a maximum diffraction peak at 5 °. In particular, the half width of the diffraction peak is more preferably 1 ° or more. Furthermore, the average particle size of the primary particles being 0.1 μm or less is sufficiently important for the subsequent crystal conversion.
[0025]
FIG. 1 shows an electron micrograph showing the particle state of a preferred amorphous titanyl phthalocyanine. For observation of the particle state, a transmission electron microscope (TEM; Hitachi, H-9000NAR) was used. The above-mentioned amorphous titanyl phthalocyanine water paste was diluted with ion-exchanged water so that the pigment concentration was about 1% by weight, scooped on a conductive net, dried as it was, and observed. The scale bar in the figure is 0.2 μm.
[0026]
Next, a crystal conversion method will be described.
In the present invention, titanyl phthalocyanine crystals are synthesized from at least two crystal conversion steps.
First, the first crystal conversion method will be described. In the first crystal conversion, the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) is used as a diffraction peak (± 0.2 °) of Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm). It has a maximum diffraction peak at 2 °, a major peak at 9.4 °, 9.6 ° and 24.0 °, and a peak at 7.3 ° as the lowest diffraction peak. And 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 °.
[0027]
As a specific method, the crystalline form is obtained by mixing and stirring together with an organic solvent in the presence of water without drying the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine). . At this time, it is a point of the present invention to control the average particle size of the primary particles of the titanyl phthalocyanine crystal after crystal conversion to 0.2 μm or less.
[0028]
In this case, any organic solvent can be used as long as the desired crystal form can be obtained, but tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, 1,1, Good results are obtained when one selected from 2-trichloroethane is selected. These organic solvents are preferably used alone, but two or more of these organic solvents may be mixed or used in combination with other solvents.
In the operation of crystal conversion, the 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 (mostly 0.01 to 0). However, it was found that during crystal conversion, the crystal was converted with crystal growth. Usually, in this type of crystal conversion, a sufficient crystal conversion time is ensured due to fear of remaining of the raw material, and after the crystal conversion is sufficiently performed, filtration is performed to obtain a titanyl phthalocyanine crystal having a desired crystal type. Is what you get. For this reason, even though a raw material having sufficiently small primary particles is used as a raw material, a crystal having a large primary particle (approximately 0.3 to 0.5 μm) is obtained as a crystal after crystal conversion. is there.
[0029]
The state of the primary particles of such a crystal is shown in FIG. The observation in FIG. 2 was also performed by TEM in the same manner as in FIG. Two very large primary particles are observed near the center of the photograph. The scale bar in the figure is 0.2 μm.
[0030]
In dispersing the titanyl phthalocyanine crystal produced in this way, in order to make the particle size after dispersion small (about 0.2 μm or less), dispersion is performed by giving a strong share, and further if necessary. Dispersion is performed by applying strong energy to pulverize the primary particles. As a result, as described above, a part of the particles is transferred to a crystal type that is not a desired crystal type.
[0031]
On the other hand, in the present invention, the range in which crystal growth hardly occurs at the time of crystal conversion (the size of the amorphous titanyl phthalocyanine particles observed in FIG. 1 is kept in a small size, approximately 0.2 μm or less after crystal conversion. In other words, it is intended to obtain a titanyl phthalocyanine crystal having the smallest primary particle size as much as possible by determining when the crystal conversion is completed. The particle size after crystal conversion increases in proportion to the crystal conversion time. For this reason, as described above, it is important to increase the efficiency of crystal conversion and complete it in a short time. There are several important points for this.
[0032]
One is to select an appropriate crystal conversion solvent as described above to increase the crystal conversion efficiency. The other is to use strong agitation to bring the solvent into contact with the titanyl phthalocyanine aqueous paste (raw material prepared as described above) in order to complete the crystal conversion in a short time. Specifically, it is possible to achieve crystal conversion in a short time by using a propeller with a very strong stirring force or using a strong stirring (dispersing) means such as a homogenizer (homomixer). is there. Under these conditions, it is possible to obtain a titanyl phthalocyanine crystal in a state in which crystal conversion is sufficiently performed and crystal growth does not occur without remaining raw materials.
[0033]
In addition, since the crystal grain size and the crystal conversion time are in a proportional relationship as described above, a method of immediately stopping the reaction when a predetermined reaction (crystal conversion) is completed is also an effective means. As the above-mentioned means, it is possible to immediately add a large amount of a solvent in which crystal conversion hardly occurs after crystal conversion as described above. Examples of the solvent that hardly causes crystal transformation include alcohol solvents and ester solvents. Crystal conversion can be stopped by adding about 10 times these solvents to the crystal conversion solvent.
[0034]
The smaller the primary particle size produced in this way, the better the results for the problem of the photoreceptor, but the next step for pigment preparation (pigment filtration step), dispersion in dispersion In consideration of stability, side effects may occur even if it is too small. That is, when the primary particles are very fine, there arises a problem that the filtration time becomes very long in the step of filtering the primary particles. In addition, when the primary particles are too fine, the surface area of the pigment particles in the dispersion increases, and the possibility of reaggregation of the particles increases. Therefore, the suitable particle size of the pigment particles is in the range of about 0.05 μm to 0.2 μm.
[0035]
FIG. 3 shows a TEM image of a titanyl phthalocyanine crystal when crystal conversion is performed in a short time. Unlike the case of FIG. 2, the particle size is small and almost uniform, and no coarse particles as observed in FIG. 2 are observed. The scale bar in the figure is 0.2 μm.
[0036]
Subsequently, the crystallized titanyl phthalocyanine crystal is immediately filtered to be separated from the crystal conversion solvent. This filtration is performed by using a filter of an appropriate size. In this case, it is most appropriate to use vacuum filtration.
Thereafter, the separated titanyl phthalocyanine crystal is heat-dried as necessary. As the dryer used for heating and drying, known ones can be used, but a blower-type dryer is preferable when the drying is performed in the atmosphere. Furthermore, drying under reduced pressure is a very effective means in order to increase the drying speed and to exhibit the effects of the present invention more remarkably. 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.
[0037]
Next, the second crystal conversion method will be described. The second crystal conversion is a step of further crystal conversion using the titanyl phthalocyanine crystal (dry powder) prepared by the first crystal conversion. Specific methods include two methods.
One is a method of treating the previously prepared titanyl phthalocyanine crystal in an organic solvent. Any organic solvent can be used as long as it can convert the crystal form having the maximum diffraction peak at 27.2 ° to the crystal form having the maximum diffraction peak at 26.3 °. Aromatic hydrocarbons such as xylene, ketones such as acetone and 2-butanone, halogenated hydrocarbons such as methylene chloride and chloroform, and cyclic ethers such as tetrahydrofuran are preferably used. Regarding the treatment of the organic solvent, the titanyl phthalocyanine crystal may be simply immersed in the organic solvent as it is, but the treatment time can be shortened by using auxiliary means such as stirring and ultrasonic application together. ,It is valid. After the treatment with an organic solvent, the target titanyl phthalocyanine crystal can be obtained by separating by filtration and drying again.
[0038]
As another method, a crystal transformation is performed by applying a mechanical shearing force to the previously prepared titanyl phthalocyanine crystal. At this time, an organic solvent may be used in combination, but it is desirable to perform the treatment in a dry state without using it together. As a method to be used, dry milling using a ball mill, attritor, vibration mill, kneader, or the like, or simply dry milling using a mixer is also effective. Moreover, you may use inorganic salts, such as salt, as an adjuvant in the case of dry milling. When an auxiliary agent is used, a washing step for removing inorganic salts is necessary after the crystal conversion treatment. Thus, the target titanyl phthalocyanine crystal can be obtained.
[0039]
Whichever method is used, it is important that the peak intensity at 26.3 ° is in the range of 0.1 to 5% with respect to the peak intensity at the maximum diffraction peak of 27.2 °. The peak intensity of 26.3 ° is determined by the treatment time in the solvent or the treatment time giving mechanical shearing force, but the state of the raw material used (the titanyl phthalocyanine crystal produced by the first crystal conversion) (for example, It is desirable to determine the treatment time through preliminary experiments because it varies depending on the size and hardness of the powder.
[0040]
The thus obtained titanyl phthalocyanine crystal having a specific crystal type and having primary particles of 0.2 μm or less is extremely useful as a charge generating material for an electrophotographic photoreceptor. However, as described above, the crystal form is unstable, and the crystal form is easily transferred when a dispersion is prepared. However, by synthesizing primary particles into infinitely small particles as in the present invention, a dispersion with a small average particle diameter can be prepared without giving an excessive share during the preparation of the dispersion, and the crystal form is also extremely high. It can be produced stably (without changing the synthesized crystal form).
[0041]
A general method is used for the preparation of the dispersion, and the titanyl phthalocyanine crystal is dispersed in a suitable solvent together with a binder resin as necessary by using a ball mill, an attritor, a sand mill, a bead mill, an ultrasonic wave, or the like. It is obtained. At this time, the binder resin may be selected depending on the electrostatic characteristics of the photoreceptor, and the solvent may be selected depending on the wettability to the pigment and the dispersibility of the pigment.
[0042]
The intensity ratio of the 26.3 ° peak intensity to the 27.2 ° peak intensity in the titanyl phthalocyanine crystal of the present invention will be described.
An X-ray diffraction spectrum is measured with a general X-ray diffractometer in a powder state of the titanyl phthalocyanine crystal to be used. Baseline correction is performed on the obtained spectrum, and then a peak intensity of 26.3 ± 0.2 ° and a peak intensity of 27.2 ± 0.2 ° are obtained. Using the value, the value obtained by dividing the peak intensity of 26.3 ± 0.2 ° by the peak intensity of 27.2 ± 0.2 ° is the peak intensity ratio in the present invention.
[0043]
[Expression 1]
Peak intensity ratio (%) = 26.3 ± 0.2 ° peak intensity / 27.2 ± 0.2 ° peak intensity
[0044]
When the peak intensity ratio is 1% or less, it may be difficult to correct the baseline in measurement over a wide range. In that case, the intensity ratio can be obtained more accurately by narrowing the measurement range (for example, measuring within a range of 25 to 30 °) and performing remeasurement.
[0045]
Hereinafter, the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
FIG. 4 is a cross-sectional view showing the electrophotographic photosensitive member of the present invention. On the conductive support (41), a charge generation layer (45) containing a charge generation material as a main component and a charge transport material as a main component. Charge transport layer (47).
FIG. 5 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member of the present invention, in which a protective layer (49) is laminated on the charge generation layer (45) and the charge transport layer (47). Have taken.
[0046]
The conductive support (41) has a volume resistance of 10 ¹⁰ Films having conductivity of Ω · cm or less, for example, metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, metal oxide such as tin oxide, indium oxide, etc. are deposited or sputtered. Shaped or cylindrical plastic, paper-coated, or aluminum, aluminum alloy, nickel, stainless steel, etc., and after making them into tubes by methods such as extrusion and drawing, cutting, superfinishing, polishing, etc. A surface-treated tube or the like can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as the conductive support (41).
[0047]
Of these, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. As used herein, aluminum includes both pure aluminum and aluminum alloys. Specifically, aluminum or aluminum alloy of JIS 1000s, 3000s, and 6000s is most suitable. Anodized films are obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, a film called anodized aluminum or an aluminum alloy that has been anodized in an electrolyte solution is used in the present invention. Is the most suitable. In particular, it is excellent in preventing point defects (black spots, background stains) that occur when used in reversal development (negative / positive development).
[0048]
The anodizing treatment is performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10-20%, bath temperature: 5-25 ° C., current density: 1-4 A / dm ² The treatment is carried out in the range of electrolytic voltage: 5 to 30 V, treatment time: about 5 to 60 minutes, but is not limited thereto. Since the anodic oxide film thus produced is porous and has high insulation, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodized film is likely to change. In order to avoid this, it is desirable to further seal the anodized film. Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized steam. Among these, the method of immersing in the aqueous solution containing nickel acetate is the most preferable. Subsequent to the sealing treatment, the anodic oxide film is washed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment. If this remains excessively on the surface of the support (anodized film), it not only adversely affects the quality of the coating film formed on this surface, but also generally low resistance components remain, resulting in the occurrence of soiling. It can also be a cause. The cleaning may be performed once with pure water, but is usually performed at another stage. At this time, it is preferable that the final cleaning liquid is as clean as possible (deionized). Moreover, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning processes. The film thickness of the anodized film formed as described above is preferably about 5 to 15 μm. If it is too thin, the barrier effect as an anodic oxide film is not sufficient, and if it is too thick, the time constant as an electrode becomes too large, resulting in the generation of residual potential and the response of the photoreceptor. There is a case.
[0049]
In addition to this, a conductive support dispersed in a suitable binder resin and coated with conductive powder on the above support can also be used as the conductive support (41) 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, or metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin used at the same time is 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, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
[0050]
Furthermore, a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer can be used favorably as the conductive support (41) of the present invention.
[0051]
Next, the photosensitive layer will be described.
The charge generation layer (45) is a layer mainly composed of titanyl phthalocyanine crystal having an average primary particle size of 0.2 μm or less as a charge generation material. Preferably, the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα has a maximum diffraction peak at least 27.2 °, and further 9.4 °, 9 It has major peaks at .6 ° and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and has a peak in the range of 7.4 to 9.4 °. And having a peak at 26.3 ° (preferably, the peak intensity at 26.3 ° is in the range of 0.1 to 5% with respect to the peak intensity at 27.2 °) It is a layer mainly composed of titanyl phthalocyanine crystal characterized by having a major axis of 0.2 μm or less.
[0052]
In the charge generation layer (45), the pigment is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is applied onto a conductive support, It is formed by drying.
The binder resin used for the charge generation layer (45) as required includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon 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, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulosic resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone Etc. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material.
[0053]
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 coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used. The film thickness of the charge generation layer (45) is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.
[0054]
The charge transport layer (47) can be formed by dissolving or dispersing a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
Charge transport materials include hole transport materials and electron transport materials. Examples of the charge transport material 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-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.
[0055]
Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.
[0056]
The binder resin is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin And thermoplastic or thermosetting resins such as alkyd resins.
[0057]
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 100 μm. As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.
[0058]
For the charge transport layer (47), a polymer charge transport material having a function as a charge transport material and a binder resin is also preferably used. The charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. As the polymer charge transport material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, the polymer charge transport materials represented by the formulas (I) to (X) are favorably used, and these are exemplified below and specific examples are shown.
[0059]
[Chemical 1]
(I) Formula

Where R ₁ , R ₂ , R ₃ Each independently represents a substituted or unsubstituted alkyl group or a halogen atom, R 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, q are each independently an integer of 0-4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, 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. In the formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0060]
[Chemical 2]

R ₁₀₁ , R ₁₀₂ Each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 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
[0061]
[Chemical 3]

(A is an integer from 1 to 20, b is an integer from 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. )
[0062]
[Formula 4]
(II) Formula

Where R ₇ , R ₈ Is a substituted or unsubstituted aryl group, Ar ₁ , Ar ₂ , Ar ₃ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0063]
[Chemical formula 5]
(III) Formula

Where R ₉ , R ₁₀ Is a substituted or unsubstituted aryl group, Ar ₄ , Ar ₅ , Ar ₆ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0064]
[Chemical 6]
(IV) Formula

Where R ₁₁ , R ₁₂ Is a substituted or unsubstituted aryl group, Ar ₇ , Ar ₈ , Ar ₉ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0065]
[Chemical 7]
(V) Formula

Where R ₁₃ , 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 formula (I). In the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0066]
[Chemical 8]
(VI) Formula

Where R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ Is a substituted or unsubstituted aryl group, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , Ar ₁₆ Are the same or different arylene groups, 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, or a vinylene group, which may be the same or different. X, k, j and n are the same as in the case of formula (I). In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0067]
[Chemical 9]
(VII) Formula

Where R ₁₉ , R ₂₀ Represents a hydrogen atom, a substituted or unsubstituted aryl group, and R ₁₉ And R ₂₀ May form a ring. Ar ₁₇ , Ar ₁₈ , Ar ₁₉ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0068]
Embedded image
(VIII) Formula

Where R ₂₁ Is a substituted or unsubstituted aryl group, Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , Ar ₂₃ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0069]
Embedded image
(IX) Formula

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 Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0070]
Embedded image
(X) Formula

Where R ₂₆ , R ₂₇ Is a substituted or unsubstituted aryl group, Ar ₂₉ , Ar ₃₀ , Ar ₃₁ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I). In the formula (X), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
[0071]
Further, as the polymer charge transport material used in the charge transport layer, in addition to the polymer charge transport material described above, in the state of the monomer or oligomer having an electron donating group at the time of film formation of the charge transport layer, A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by carrying out a curing reaction or a crosslinking reaction.
[0072]
A charge transport layer composed of a polymer having these electron donating groups or a polymer having a crosslinked structure is excellent in wear resistance. Usually, in the electrophotographic process, since the charging potential (unexposed portion potential) is constant, if the surface layer of the photoreceptor is worn by repeated use, the electric field strength applied to the photoreceptor increases accordingly. As the electric field strength increases, the occurrence frequency of scumming increases. Therefore, the high wear resistance of the photosensitive member is advantageous for scumming. The charge transport layer composed of a polymer having these electron donating groups is a polymer compound, so it has excellent film-forming properties and has a charge transport site compared to a charge transport layer composed of a low molecular weight dispersed polymer. It can be configured with high density and has excellent charge transport capability. For this reason, a photoreceptor having a charge transport layer using a polymer charge transport material can be expected to have a high response speed.
[0073]
Examples of the other polymer having an electron donating group include a copolymer of a known monomer, a block polymer, a graft polymer, a star polymer, and, for example, JP-A-3-109406, JP-A 20000- It is also possible to use a crosslinked polymer having an electron-donating group as disclosed in JP-A-206723, JP-A No. 2001-34001, and the like. Also in this case, a material that can satisfy the above mobility can be used effectively.
[0074]
In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer (47). As the plasticizer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used 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, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 0 with respect to the binder resin. 1% by weight is suitable.
[0075]
As the binder resin, the binder resin previously mentioned in the charge transport layer (47) may be used as it is, or the binder resin mentioned in the charge generation layer (45) may be mixed and used. Of course, the polymer charge transport materials mentioned above can also be used favorably. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight. A single-layer photosensitive layer is formed by dip coating or spraying with a coating solution dispersed with a disperser using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane together with a charge transport material, if necessary, with a charge generating material and a binder resin. It can be formed by coating with a coat or bead coat. The thickness of the single photosensitive layer is suitably about 5 to 100 μm.
[0076]
In the electrophotographic photosensitive member of the present invention, an undercoat layer can be provided between the conductive support (41) and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.
[0077]
These undercoat layers can be formed using an appropriate solvent and coating method as in the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, the undercoat layer of the present invention includes Al. ₂ O ₃ Anodic oxidation, organic materials such as polyparaxylylene (parylene), and SiO ₂ , SnO ₂ TiO ₂ , ITO, CeO ₂ A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.
[0078]
In the photoreceptor of the present invention, a protective layer (49) may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. Materials used for the protective layer (49) include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone. , Polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane , Resins such as polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Of these, polycarbonate or polyarylate can be most preferably used.
[0079]
In addition to the protective layer (49), a fluorine resin such as polytetrafluoroethylene, a silicone resin, and an inorganic filler such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving wear resistance. Moreover, what disperse | distributed the organic filler etc. can be added.
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. Metal powder such as copper, tin, aluminum, indium, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin oxide doped indium oxide, etc. And inorganic materials such as metal oxides and potassium titanate. In particular, it is advantageous to use an inorganic material from the viewpoint of the hardness of the filler. In particular, silica, titanium oxide, and alumina can be used effectively. Further, among these, α-alumina having a hexagonal close-packed structure can be most effectively used.
[0080]
The filler concentration in the protective layer varies depending on the type of filler used and also on the electrophotographic process conditions using the photoconductor, but the ratio of filler to the total solid content on the outermost layer side of the protective layer is preferably 5% by weight or more, preferably It is 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less.
Further, the volume average particle size of the filler used is preferably in the range of 0.1 μm to 2 μm, and preferably in the range of 0.3 μm to 1 μm. In this case, if the average particle size is too small, the wear resistance is not sufficiently exhibited, and if it is too large, the surface property of the coating film is deteriorated or the coating film itself cannot be formed.
[0081]
The average particle diameter of the filler in the present invention is a volume average particle diameter unless otherwise specified, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba). At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. In addition, it is important that the standard deviation of each particle measured simultaneously is 1 μm or less. If the standard deviation is greater than this, the particle size distribution may be too wide, and the effects of the present invention may not be obtained significantly.
[0082]
Further, the pH of the filler used in the present invention greatly affects the resolution and the dispersibility of the filler. One possible reason is that hydrochloric acid or the like remains in the filler, particularly the metal oxide, during production. When the remaining amount is large, the occurrence of image blur is unavoidable, and depending on the remaining amount, the dispersibility of the filler may be affected.
Another reason is due to the difference in chargeability on the surface of the filler, particularly the metal oxide. Normally, particles dispersed in a liquid are charged positively or negatively, and ions having opposite charges gather to try to keep it electrically neutral, and an electric double layer is formed there. The dispersed state of the particles is stabilized. The potential (zeta potential) gradually decreases with increasing distance from the particle, and the potential in a region that is sufficiently away from the particle and electrically neutral is 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 they approach 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.
In the configuration of the present invention, the filler having a pH at the isoelectric point of at least 5 is preferably from the viewpoint of image blur suppression, and the more basic the filler, the higher the effect. It was confirmed that there was. The filler having a high basic pH at the isoelectric point has a higher zeta potential when the system is acidic, so that dispersibility and stability thereof are improved.
Here, the pH of the filler in the present invention is the pH value at the isoelectric point from the zeta potential. At this time, the zeta potential was measured with a laser zeta potential meter manufactured by Otsuka Electronics Co., Ltd.
[0083]
Furthermore, as a filler that hardly causes image blur, a filler having high electrical insulation (specific resistance is 10%). ¹⁰ (Ω · cm or more) is preferable, and those having a filler pH of 5 or more and those having a 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 can be used alone, or two or more fillers having a pH of 5 or less and a filler having a pH of 5 or more can be mixed. It is also possible to use a mixture of two or more fillers having a dielectric constant of 5 or less and fillers having a dielectric constant of 5 or more. Among these fillers, α-type alumina, which has high insulation properties, high thermal stability, and high wear resistance, is a hexagonal close-packed structure, from the viewpoint of suppressing image blur and improving wear resistance. It is particularly useful.
[0084]
The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance value of a powder such as a filler varies depending on the filling rate, it is necessary to measure under certain conditions. In the present invention, the specific resistance value of the filler is determined using an apparatus having the same configuration as the measuring apparatus shown in FIG. 1 of JP-A-5-94049 and FIG. 1 of JP-A-5-113688. Measured and used this value. In the measuring device, the electrode area is 4.0 cm. ² It is. Prior to measurement, a load of 4 kg is applied to one electrode for 1 minute, and the sample amount is adjusted so that the distance between the electrodes is 4 mm. At the time of measurement, the measurement is performed with the upper electrode weight (1 kg) loaded, and the applied voltage is measured at 100V. 10 ⁶ The area above Ω · cm was measured with HIGH RESISTANCE METER (Yokogawa Hewlett Packard), and the area below it was measured with a digital multimeter (Fluk). The specific resistance value obtained in this way is defined as the specific resistance value according to the present invention.
[0085]
The dielectric constant of the filler was measured as follows. Using a cell similar to the measurement of the specific resistance as described above, after applying a load, the capacitance was measured, and the dielectric constant was determined from this. The capacitance was measured by using a dielectric loss measuring device (Ando Electric).
[0086]
Furthermore, these fillers can be surface-treated with at least one surface treatment agent, and it is preferable from the viewpoint of filler dispersibility. Lowering the dispersibility of the filler not only increases the residual potential, but also lowers the transparency of the coating, causes defects in the coating, and lowers the wear resistance. It can develop into a big problem. As the surface treatment agent, a conventionally used surface treatment agent can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable. For example, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, higher fatty acids, etc., or mixed treatment of these with silane coupling agents, Al ₂ O ₃ TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, etc., or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur. The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30 wt%, more preferably 5 to 20 wt%. If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be 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 to be used with respect to the filler amount as described above.
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 primary particle level and has less aggregates.
[0087]
Further, the protective layer (49) may contain a charge transport material for reducing residual potential and improving responsiveness. As the charge transport material, the materials described in the description of the charge transport 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. In order to improve wear resistance, it is an effective means to reduce the concentration of the surface side. The concentration referred to here represents the ratio of the weight of the low molecular charge transporting material to the total weight of all the materials constituting the protective layer, and the concentration gradient is a gradient that lowers the concentration on the surface side in the above weight ratio. It shows that. The use of a polymer charge transport material is very advantageous in terms of enhancing the durability of the photoreceptor.
By constituting the components other than the filler of the protective layer only with the polymer, not only the mechanical wear resistance can be improved, but also the chemical stability can be enhanced. A polymer has poor chemical reactivity compared to a low molecule, and has a high resistance to an oxidizing gas generated from a charging member, or a high resistance to a sputtering effect caused by a discharge. When the surface has a highly wear-resistant film such as a protective layer, the problem of image blur due to repeated use becomes very significant. This is thought to be due to adsorption of oxidizing gas and adhesion (adsorption) of low-resistance substances on the surface of the photoconductor. However, as described above, a protective layer consisting only of filler and polymer components is used. In this case, the number of adsorption sites is reduced, which shows a high effect on image blur.
As a method for forming the protective layer, a normal coating method is employed. In addition, about 0.1-10 micrometers is suitable for the thickness of a protective layer. In addition to the above, a known material such as a-C or a-SiC formed by a vacuum thin film forming method can be used as the protective layer.
As described above, the use of a polymer charge transport material for the photosensitive layer (charge transport layer) or the provision of a protective layer on the surface of the photoreceptor increases the durability (wear resistance) of each photoreceptor. In addition, when used in a tandem full-color image forming apparatus, it produces a new effect not found in a monochrome image forming apparatus.
In the case of a full-color image, various types of images are input, but on the contrary, a typical image may also be input. For example, the presence of a seal in a Japanese document or the like. Things like indicia are usually located towards the edge of the image area, and the colors used are also limited. Also, full-color machines are becoming tandem, and the printing speed has been greatly improved. For this reason, the output of business documents is increasing, and for example, the number of cases where a form (document) using a company logo is output is increasing. In such a case, since printing is performed only at a specific location, the bias in use of the photosensitive member is further increased. In a state in which a random image is always written, image writing, development, and transfer are performed on the photoconductor in the image forming element on average. When many image formations are repeated or only a specific image forming element is used, the durability balance is lost. When a photoconductor having a low surface durability (physical / chemical / mechanical) is used in such a state, this difference becomes prominent and easily causes an image problem. On the other hand, when the photoconductor is made highly durable, the amount of such local change is small, and as a result, it becomes difficult to appear as a defect on the image, so that high durability is achieved and the stability of the output image is improved. This is very effective.
[0088]
In the present invention, an intermediate layer may be provided between the photosensitive layer and the protective layer. In the intermediate layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a normal coating method is employed as described above. In addition, about 0.05-2 micrometers is suitable for the thickness of an intermediate | middle layer.
[0089]
Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 6 is a schematic diagram for explaining the electrophotographic process and the electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 6, a photoconductor (21) has a specific crystal type on a conductive support, and a charge generation layer and a charge transport layer containing titanyl phthalocyanine crystals having an average primary particle size of 0.2 μm or less. Is provided. A charging member (23), a pre-transfer charger (27), a transfer charger (30), a separation charger (31), and a pre-cleaning charger (33) include a corotron, a scorotron, a solid state charger, and charging. Known means such as a roller are used. As the charging member, a member that is in contact with or close to the photoreceptor is preferably used. In addition, when charging the photosensitive member with the charging member, charging unevenness can be effectively reduced by charging the photosensitive member with an electric field in which an AC component is superimposed on a DC component on the charging member. In particular, in a tandem type full-color image forming apparatus, in addition to the problem of density unevenness of a halftone image due to charging unevenness that occurs in the case of a monochrome image forming apparatus, this leads to a large problem of deterioration in color balance (color reproducibility). The above problem is greatly improved by superimposing the AC component on the DC component, but if the AC component conditions (frequency, peak-to-peak voltage) are too large, the hazard to the photoconductor increases. In some cases, deterioration of the photoconductor may be accelerated. For this reason, superposition of alternating current components should be kept to the minimum necessary.
[0090]
The contact-type charging member here is a type in which the surface of the charging member is in contact with the surface of the photosensitive member, and includes a charging roller, a charging blade, and a charging brush. Among them, a charging roller and a charging brush are used favorably.
Further, the charging member arranged in the proximity is a type in which the charging member is arranged in a non-contact state so as to have a gap (gap) of 200 μm or less between the surface of the photoreceptor and the charging member surface. If this gap is too large, the charging tends to become unstable, and if it is too small, the surface of the charging member may be contaminated when toner remaining on the photoreceptor exists. . Therefore, the gap is suitably 10 to 200 μm, preferably 10 to 100 μm. From the distance of the air gap, it is distinguished from known charging wire type chargers such as corotrons and scorotrons, contact charging members such as contact type charging rollers, charging brushes and charging blades.
[0091]
The adjacently arranged 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 surface of the photoreceptor. For example, the rotation shaft of the photosensitive member and the rotation shaft 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, a gap forming member is disposed at both ends of the non-image forming portion of the charging member, and only this portion is brought into contact with the surface of the photoreceptor, and the image forming region is disposed in a non-contact manner. Alternatively, the gap forming member at both ends of the non-photosensitive portion of the photoconductor is disposed, and only this portion is brought into contact with the surface of the charging member, and the image forming region is disposed in a non-contact manner, so that the gap can be stably stabilized. It is a method that can be maintained. In particular, the methods described in JP-A Nos. 2002-148904 and 2002-148905 can be used satisfactorily. An example of the proximity charging mechanism in which the gap forming member is arranged on the charging member side is shown in FIG.
[0092]
As the transfer means, the above charger can be generally used. However, as shown in FIG. 6, a combination of a transfer charger (30) and a separation charger (31) is effective.
An LD or LED is used as the light source of the image exposure unit (25). Use light sources such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescence (ELs) as light sources such as static elimination lamps (22). Can do. Various types of 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 to irradiate only light in a desired wavelength range.
Such a light source or the like irradiates the photosensitive member with light by providing a transfer step, a static elimination step, a cleaning step, or a pre-exposure step in combination with light irradiation in addition to the steps shown in FIG.
[0093]
The toner developed on the photoconductor (21) by the developing unit (26) is transferred to the transfer paper (29), but not all is transferred and remains on the photoconductor (21). Toner is also produced. Such toner is removed from the photoreceptor by the fur brush (34) and the blade (35). 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.
[0094]
When the electrophotographic photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.
A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.
[0095]
FIG. 8 shows another example of the electrophotographic process according to the present invention. The photoreceptor (61) has a charge generation layer and a charge transport layer containing a titanyl phthalocyanine crystal having a specific crystal type and an average primary particle size of 0.2 μm or less on a conductive support. Become. Driven by driving rollers (62a) and (62b), charged by a charger (63), image exposure by a light source (64), development (not shown), transfer using a charger (65), by a light source (66) Exposure before cleaning, cleaning with a brush (67), and static elimination with a light source (68) are repeated. In FIG. 8, light exposure for image exposure is performed on the photoconductor 61 (of course, the support is translucent) from the support side. The image exposure source (64) is preferably an LD or an LED.
[0096]
The above illustrated electrophotographic process exemplifies an embodiment of the present invention, and of course, other embodiments are possible. For example, in FIG. 8, the pre-cleaning exposure is performed from the photosensitive layer side, but this may be performed from the translucent support side, or irradiation with static elimination light may be performed from the support side.
On the other hand, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and static elimination exposure. In addition, a pre-transfer exposure, a pre-exposure of image exposure, and other known light irradiation processes are provided to light the photosensitive member. Irradiation can also be performed.
[0097]
The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. The photoreceptor (76) has a charge generation layer and a charge transport layer containing titanyl phthalocyanine crystals having a specific crystal type and an average primary particle size of 0.2 μm or less on a conductive support. Become.
[0098]
FIG. 10 is a schematic diagram for explaining the tandem-type full-color electrophotographic apparatus of the present invention, and modifications as described below also belong to the category of the present invention.
In FIG. 10, reference numerals (1C), (1M), (1Y) and (1K) are drum-shaped photoconductors, and these photoconductors (1C), (1M), (1Y) and (1K) are shown in the figure. The charging member (2C), (2M), (2Y) and (2K), the developing member (4C), (4M), (4Y) and (4K), cleaning at least in the order of rotation Members (5C), (5M), (5Y) and (5K) are arranged. The charging members (2C), (2M), (2Y), and (2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor. From the charging member (2C), (2M), (2Y) and (2K) to the surface of the photoreceptor between the developing member (4C), (4M), (4Y) and (4K), an exposure member (not shown) Laser light (3C), (3M), (3Y) and (3K) are irradiated, and an electrostatic latent image is formed on the photoconductors (1C), (1M), (1Y) and (1K). ing. Then, the four image forming elements (6C), (6M), (6Y) and (6K) centering on such photoconductors (1C), (1M), (1Y) and (1K) serve as transfer materials. They are juxtaposed along a transfer conveyance belt (10) that is a conveyance means. The transfer / conveying belt (10) includes developing members (4C), (4M), (4Y) and (4K) and cleaning members (5C) of the image forming units (6C), (6M), (6Y) and (6K). , (5M), (5Y) and (5K) are in contact with the photoconductors (1C), (1M), (1Y) and (1K) and hit the back side of the transfer conveyance belt (10) on the photoconductor side. 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) is different in the color of the toner inside the developing device, and the others are the same in configuration.
[0099]
In the color electrophotographic apparatus having the configuration shown in FIG. 10, 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) are in the direction indicated by the arrow (the direction around the photoconductor). ) Are rotated by charging members (2C), (2M), (2Y) and (2K) which are rotated, and laser light (3C), (3M) is then exposed by an exposure unit (not shown) disposed inside the photoreceptor. ), (3Y) and (3K) form an electrostatic latent image corresponding to each color image to be created. Next, the latent image is developed by the developing members (4C), (4M), (4Y), and (4K) to form a toner image. Developing members (4C), (4M), (4Y), and (4K) are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. The toner images of the respective colors formed on the two photoconductors (1C), (1M), (1Y) and (1K) are superimposed on the transfer paper. The transfer paper (7) is fed out from the tray by a paper feed roller (8), temporarily stopped by a pair of registration rollers (9), and is transferred to the transfer conveyance belt (10) in synchronization with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer conveyance belt (10) is conveyed, and each color is in contact position (transfer section) with each photoconductor (1C), (1M), (1Y) and (1K). The toner image is transferred. The toner image on the photoconductor includes the transfer bias applied to the transfer brushes (11C), (11M), (11Y), and (11K) and the photoconductors (1C), (1M), (1Y), and (1K). The image is transferred onto the transfer paper (7) by an electric field formed from the potential difference. Then, the recording paper (7) on which the toner images of four colors are superimposed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (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 the cleaning devices (5C), (5M), (5Y), and ( 5K). In the example of FIG. 10, 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 conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism that stops the image forming elements (6C), (6M), and (6Y) other than black. Further, in FIG. 10, the charging member is in contact with the photosensitive member, but by providing an appropriate gap (about 10 to 200 μm) between them, the wear amount of both can be reduced and the charging member can be applied to the charging member. Less toner filming is required and it can be used satisfactorily.
[0100]
The image forming means as described above may be fixedly incorporated in a copying apparatus, facsimile, or printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. . A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like.
[0101]
【Example】
Hereinafter, although an example is given and the present invention is explained, the present invention is not restricted by an example. All parts are parts by weight.
First, a specific synthesis example of a crystalline titanyl phthalocyanine pigment having a maximum diffraction peak with a Bragg angle 2θ of 27.2 ° ± 0.2 ° will be described.
Example 1
292 parts of 1,3-diiminoisoindoline and 1800 parts of sulfolane are mixed, and 204 parts of titanium tetrabutoxide are 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 by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After completion of the reaction, the mixture was allowed to cool, and then the precipitate was filtered, washed with chloroform until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried. Crude titanyl phthalocyanine was obtained.
60 parts of the obtained crude titanyl phthalocyanine pigment washed with hot water were stirred and dissolved in 1000 parts of 96% sulfuric acid at 3 to 5 ° C. and filtered. The obtained sulfuric acid solution was added dropwise to 35000 parts of ice water with stirring, the precipitated crystals were filtered, and then washed with water until the washing solution became neutral to obtain an aqueous paste of titanyl phthalocyanine pigment.
To this water paste, 1500 parts of tetrahydrofuran was added, and stirred vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature. Stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filter were washed with tetrahydrofuran to obtain 98 parts of a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 78 parts of titanyl phthalocyanine crystals.
Further, 30 g of this titanyl phthalocyanine crystal was immersed in 300 g of tetrahydrofuran, and a second crystal conversion was performed. After leaving it immersed for 12 hours, it was separated by filtration and dried under reduced pressure under the same conditions as above to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 1.
[0102]
(Example 2)
The treatment was carried out in the same manner as in Example 1 except that the second crystal conversion time in Example 1 was changed from 12 hours to 24 hours to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 2.
[0103]
(Example 3)
The treatment was carried out in the same manner as in Example 1 except that the second crystal conversion solvent in Example 1 was changed from tetrahydrofuran to 2-butanone to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 3.
[0104]
Example 4
The treatment was carried out in the same manner as in Example 1 except that the second crystal conversion operation in Example 1 was changed to the following conditions to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 4.
(Second crystal conversion process)
30 g of titanyl phthalocyanine crystals subjected to the first crystal conversion treatment were subjected to mechanical shearing force for 5 minutes by a commercially available mixer, and then the powder was taken out.
[0105]
(Example 5)
The treatment was carried out in the same manner as in Example 1 except that the second crystal conversion operation in Example 1 was changed to the following conditions to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 5.
(Second crystal conversion process)
30 g of titanyl phthalocyanine crystals subjected to the first crystal conversion treatment were put into a φ90 mm glass pot together with 2 kg of φ6 mm zirconia balls, and after dry milling for 10 minutes, the powder was taken out.
[0106]
(Comparative Example 1)
In the crystal conversion treatment with tetrahydrofuran in Example 1, in the same manner as in Example 1 except that the crystal conversion time was set to 4 hours in accordance with the method of Synthesis Example 1 described in JP-A-2001-187794, A titanyl phthalocyanine crystal was obtained. This is designated as Pigment 6.
[0107]
(Comparative Example 2)
In Example 1, in the crystal conversion treatment with tetrahydrofuran, in accordance with the method of Synthesis Example 1 described in JP-A No. 2001-187794, the crystal conversion time was set to 4 hours, and then allowed to stand still overnight. A titanyl phthalocyanine crystal was obtained in the same manner as in Example 1 except that filtration was performed the next day. This is designated as Pigment 7.
[0108]
(Comparative Example 3)
In Example 1, a treatment was carried out in the same manner as in Example 1 except that the second crystal conversion treatment was not carried out to obtain a titanyl phthalocyanine crystal. This is designated as Pigment 8.
[0109]
(Comparative Example 4)
In Example 1, 2-butanone was used in place of tetrahydrofuran as the first crystal conversion solvent, and the treatment was performed in the same manner as in Example 1 except that the second crystal conversion was not performed. Thus, titanyl phthalocyanine crystals were obtained. . This is designated as Pigment 9.
[0110]
Part of the water paste prepared in Example 1 was diluted with ion-exchanged water to approximately 1% by weight, and the surface was scooped with a copper net having a conductive treatment, and the titanyl phthalocyanine particle size was determined as transmission electron. Observation was performed with a microscope (TEM, Hitachi: H-9000NAR) at a magnification of 75000 times. The average particle size was determined as follows.
The TEM image observed as described above is taken as a TEM photograph, and 30 titanyl phthalocyanine particles (a shape close to a needle shape) projected are arbitrarily selected, and the size of each major axis is measured. The arithmetic average of the major diameters of the 30 individuals measured was determined as the average particle size.
The average particle size in the water paste in Example 1 determined by the above method was 0.06 μm.
[0111]
TEM observation was performed on the titanyl phthalocyanine crystal after crystal conversion just before filtration in the first crystal conversion in Example 1 and Comparative Examples 1 to 2 and 4 by the same method as the above water paste. Each was subjected to a predetermined crystal conversion treatment, and the liquid immediately before filtration was sampled, diluted with each crystal conversion solvent to about 1% by weight, and subjected to measurement. The obtained average particle size is shown in Table 1.
In addition, the titanyl phthalocyanine crystal produced in Example 1 and Comparative Examples 1-2, and 4 was not the same in shape of the crystal unlike the water paste (a shape close to a triangle, a shape close to a quadrangle, etc.). For this reason, the calculation was performed with the length of the largest diagonal line of the crystal as the major axis.
[0112]
[Table 1]

[0113]
A part of the water paste obtained in Example 1 was dried at 80 ° C. under reduced pressure (5 mmHg) for 2 days to obtain a low crystalline titanyl phthalocyanine powder.
X-ray diffraction spectra of the dry powder of the water paste obtained as described above and the titanyl phthalocyanine crystals obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were measured under the following conditions.
X-ray tube: Cu
Voltage: 40 kV
Current: 20 mA
Scanning speed: 1 ° / min
Scanning range: 3 ° -40 °
Time constant: 2 seconds
An X-ray diffraction spectrum of the dry powder of the water paste is shown in FIG.
[0114]
For Examples 1 to 5 and Comparative Examples 1 and 2, since the same X-ray diffraction spectrum was shown in each case except for the peak intensity of 26.3 °, it was obtained in Example 2 as a representative example. The X-ray diffraction spectrum of the titanyl phthalocyanine crystal is shown in FIG. The X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in Comparative Example 3 is shown in FIG. 13, but it did not show a peak at 26.3 °. The X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in Comparative Example 4 is shown in FIG. 14, and the lowest angle exists at 7.5 °.
[0115]
(Comparative Example 5)
A pigment was prepared according to the method described in JP-A-1-299874. That is, the wet cake (water paste) produced in Example 1 was dried, 1 g of the dried product was added to 50 g of polyethylene glycol, and sand milling was performed with 100 g of glass beads for 1 hour. After the crystal transition, the mixture was washed successively with dilute sulfuric acid and aqueous ammonium hydroxide and dried to obtain a pigment. This is designated as Pigment 10.
[0116]
(Comparative Example 6)
A pigment was prepared in accordance with the method described in JP-A-3-269064. That is, the wet cake prepared in Example 1 was dried, and 1 g of the dried product was stirred for 1 hour (50 ° C.) 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. The pigment was obtained by drying. This is designated as Pigment 11.
[0117]
(Comparative Example 7)
A pigment was prepared according to the method described in JP-A-2-8256. 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 completion of the dropping, the temperature was gradually raised to 200 ° C., and the reaction was carried out by stirring for 3 hours while maintaining the reaction temperature between 200 ° C. and 220 ° C. After completion of the reaction, the mixture was allowed to cool to 130 ° C and filtered while hot, then washed with 1-chloronaphthalene until the powder turned blue, then washed several times with methanol, and further with hot water at 80 ° C. After washing twice, it was dried to obtain a pigment. This is designated as Pigment 12.
[0118]
(Comparative Example 8)
A pigment was prepared according to the method described in JP-A No. 64-17066. 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 dilute sulfuric acid aqueous solution, washed with ion-exchanged water until the acid content disappeared, and dried to obtain a pigment. This is designated as Pigment 13.
[0119]
(Comparative Example 9)
A pigment was prepared according to the method described in JP-A-11-5919. That is, after 20.4 parts of o-phthalodinitrile and 7.6 parts of titanium tetrachloride were heated 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 then dried to obtain 21.3 parts of 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 stirred at a high speed, and the precipitated crystals are filtered. The crystals are washed with distilled water until no acid remains, and a wet cake is obtained. The cake (assuming that the amount of phthalocyanine contained was 2 parts) was stirred in 100 parts of THF for about 5 hours, filtered, washed and dried to obtain a pigment. This is designated as Pigment 14.
[0120]
The pigments prepared in Comparative Examples 5 to 9 were measured for X-ray diffraction spectra by the same method as before, and confirmed to be the same as the spectra described in the respective publications. The above measurement results are summarized in Table 2. For pigments 4 and 5, since the peak intensity at 26.3 ° was small, the X-ray diffraction measurement scanning range was 25 ° to 30 °, and remeasurement was performed to determine the intensity ratio accurately.
[0121]
[Table 2]

[0122]
(Example 6)
A dispersion having the following composition was prepared by bead milling under the conditions shown below (this is referred to as Dispersion 1).
15 parts of titanyl phthalocyanine crystal (pigment 1) prepared in Example 1
Polyvinyl butyral (Sekisui Chemical: BX-1) 10 parts
280 parts of 2-butanone
Using a PSZ ball having a diameter of 0.5 mm in a commercially available bead mill disperser, all of 2-butanone and pigment dissolved with polyvinyl butyral were charged, and the rotor rotation speed was 1500 r. p. m. For 30 minutes to prepare a dispersion.
[0123]
(Example 7)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to Pigment 2 (this is referred to as Dispersion 2).
[0124]
(Example 8)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to Pigment 3 (this is referred to as Dispersion 3).
[0125]
Example 9
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to the pigment 4 (this is referred to as Dispersion 4).
[0126]
(Example 10)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to Pigment 5 (this is referred to as Dispersion 5).
[0127]
(Comparative Example 10)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to Pigment 6 (this is referred to as Dispersion 6).
[0128]
(Comparative Example 11)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to Pigment 7 (this is referred to as Dispersion 7).
[0129]
(Comparative Example 12)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to Pigment 8 (this is referred to as Dispersion 8).
[0130]
(Comparative Example 13)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to the pigment 9 (this is referred to as Dispersion 9).
[0131]
(Comparative Example 14)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to the pigment 10 (this is referred to as Dispersion 10).
[0132]
(Comparative Example 15)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to the pigment 11 (this is referred to as Dispersion 11).
[0133]
(Comparative Example 16)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to the pigment 12 (this is referred to as Dispersion 12).
[0134]
(Comparative Example 17)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to the pigment 13 (this is referred to as Dispersion 13).
[0135]
(Comparative Example 18)
A dispersion was prepared in the same manner as in Example 6 except that the titanyl phthalocyanine crystal in Example 6 was changed to the pigment 14 (this is referred to as dispersion 14).
[0136]
As described above, the pigment particle size (volume average particle size) in the dispersions produced in Examples 6 to 10 and Comparative Examples 10 to 18 was measured with Horiba: CAPA700. The results are shown in Table 3.
The prepared dispersion was dried and powdered, and the X-ray diffraction spectrum was measured in the same manner as described above. In each case, the same X-ray diffraction spectrum as before dispersion was shown.
[0137]
[Table 3]

[0138]
(Example 11)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition were sequentially applied and dried on an aluminum cylinder (JIS1050) having a diameter of 60 mm, and an undercoat layer of 3.5 μm, A 0.2 μm charge generation layer and a 25 μm charge transport layer were formed to produce a laminated photoreceptor (referred to as photoreceptor 1).
◎ Undercoat layer coating solution
Titanium oxide (CR-EL: Ishihara Sangyo Co., Ltd.) 70 parts
15 parts of alkyd resin
(Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals)
Melamine resin 10 parts
(Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals)
2-butanone 100 parts
◎ Charge generation layer coating solution
The dispersion 1 described above was used.
Charge transport layer coating solution
Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts
7 parts of charge transport material with the following structural formula
[0139]
Embedded image

80 parts of methylene chloride
[0140]
(Example 12)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 2 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 2).
[0141]
(Example 13)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 3 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 3).
[0142]
(Example 14)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 4 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 4).
[0143]
(Example 15)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 5 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 5).
[0144]
(Comparative Example 19)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 6 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 6).
[0145]
(Comparative Example 20)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 7 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 7).
[0146]
(Comparative Example 21)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 8 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 8).
[0147]
(Comparative Example 22)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 9 was used in place of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 9).
[0148]
(Comparative Example 23)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 10 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 10).
[0149]
(Comparative Example 24)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 11 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 11).
[0150]
(Comparative Example 25)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 12 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 12).
[0151]
(Comparative Example 26)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 13 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 13).
[0152]
(Comparative Example 27)
A photoconductor was prepared in the same manner as in Example 11 except that Dispersion 14 was used instead of Dispersion 1 as the charge generation layer coating solution in Example 11 (referred to as Photoreceptor 14).
[0153]
The electrophotographic photosensitive members of Examples 10 to 15 and Comparative Examples 19 to 27 produced as described above are mounted on the electrophotographic apparatus shown in FIG. 6, and an image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror). As a charging member, a contact type charging roller was used, and an image was output under the following charging conditions (evaluation environment was 23 ° C-55% RH, 10 ° C-15% RH, 30 ° C-90% RH). Each of the three environments).
Charging conditions:
DC bias: about −1570 V (set so that the potential of the unexposed portion on the surface of the photoreceptor before the running test is −900 V)
Using a chart with a writing rate of 6%, 20000 sheets were continuously printed, and images at the initial stage and after 20000 sheets were evaluated. In the image evaluation, a white solid image was output at the initial stage and after 20000 sheets, and the background stain was evaluated (evaluated by the following rank). At the same time, in order to measure the surface potential (unexposed portion) of the photosensitive member at the developing unit position, using a jig that can set an electrometer at the position where the developing device is mounted, The photoreceptor surface potential after image output was measured. The results are shown in Table 4.
[0154]
[Table 4-1]
Evaluation under 23 ° C-55% RH environment

[0155]
[Table 4-2]
Evaluation under 10 ° C-15% RH environment

[0156]
[Table 4-3]
Evaluation under 30 ° C-90% RH environment

Dirt rank:
5: Almost no soiling,
4: Slightly,
3: Actual use limit level,
2 or less: Level that cannot withstand actual use
[0157]
(Example 16)
A photoconductor was prepared in the same manner as in Example 14 except that the charge transport layer coating solution in Example 14 was changed to the one having the following composition.
◎ Charge transport layer coating solution
10 parts of polymer charge transport material with the following composition
(Weight average molecular weight: about 135000)
[0158]
Embedded image

0.5 parts of additive with the following structure
[0159]
Embedded image

100 parts methylene chloride
[0160]
(Example 17)
A photoconductor was prepared in the same manner as in Example 14 except that the thickness of the charge transport layer in Example 14 was 21 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 4 μm protective layer was provided. Produced.
◎ Protective layer coating solution
Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts
7 parts of charge transport material with the following structural formula
[0161]
Embedded image

α-alumina fine particles 4 parts
(Specific resistance: 2.5 × 10 ¹² (Ω · cm, average primary particle size: 0.4 μm)
500 parts of cyclohexanone
150 parts of tetrahydrofuran
[0162]
(Example 18)
A photoconductor was prepared in the same manner as in Example 14 except that the thickness of the charge transport layer in Example 14 was 21 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 4 μm protective layer was provided. Produced.
◎ Protective layer coating solution
Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts
7 parts of charge transport material with the following structural formula
[0163]
Embedded image

Titanium oxide fine particles 4 parts
(Specific resistance: 1.5 × 10 ¹⁰ (Ω ・ cm, average primary particle size: 0.5μm)
500 parts of cyclohexanone
150 parts of tetrahydrofuran
[0164]
(Example 19)
A photoconductor was prepared in the same manner as in Example 14 except that the thickness of the charge transport layer in Example 14 was 21 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 4 μm protective layer was provided. Produced.
◎ Protective layer coating solution
Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts
7 parts of charge transport material with the following structural formula
[0165]
Embedded image

4 parts of tin oxide-antimony oxide powder
(Specific resistance: 10 ⁶ (Ω ・ cm, average primary particle size 0.4μm)
500 parts of cyclohexanone
150 parts of tetrahydrofuran
[0166]
(Example 20)
A photoconductor was prepared in the same manner as in Example 14 except that the thickness of the charge transport layer in Example 14 was 21 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 4 μm protective layer was provided. Produced.
◎ Protective layer coating solution
17 parts of polymer charge transport material of the following structural formula
(Weight average molecular weight: about 135000)
[0167]
Embedded image

Alumina fine particles 4 parts
(Specific resistance: 2.5 × 10 ¹² (Ω · cm, average primary particle size: 0.4 μm)
500 parts of cyclohexanone
150 parts of tetrahydrofuran
[0168]
The electrophotographic photoreceptors of Examples 16 to 20 produced as described above were mounted on the electrophotographic apparatus shown in FIG. 6 together with the photoreceptor of Example 14, and the image exposure light source was a 780 nm semiconductor laser (using a polygon mirror). As an image writing), a contact-type charging roller was used as a charging member, and an image was output under the following charging conditions.
Charging conditions:
DC bias: -1600 V (set so that the potential of the unexposed area on the surface of the photoreceptor becomes -900 V)
Using a chart with a writing rate of 6%, 50,000 sheets were continuously printed, and images at the initial stage and after 50,000 sheets were evaluated. In the image evaluation, a white solid image was output at the initial stage and after 50000 sheets to evaluate the background stain (evaluated by the following rank).
Further, after outputting 50000 sheets, 50 images were output in an environment of 30 ° C.-90% RH.
Further, the amount of wear on the surface of the photoreceptor at an output of 50000 sheets was measured. The results are shown in Table 5.
[0169]
[Table 5]

Dirt rank:
5: Almost no soiling,
4: Slightly,
3: Actual use limit level,
2 or less: Level that cannot withstand actual use
[0170]
(Example 21)
The photosensitive member produced in Example 14 was used and mounted in the electrophotographic apparatus shown in FIG. 6 shown in FIG. 3, the image exposure light source was a semiconductor laser of 780 nm (image writing by a polygon mirror), and the figure was shown as a charging member. The image is output under the following charging conditions using a charging member for close placement (60 μm gap between the surface of the charging member and the surface of the charging member) in which a 60 μm thick insulating tape is wound around both ends of the charging roller as shown in FIG. did.
Charging conditions:
DC bias: about -1620V (set so that the potential of the unexposed area on the surface of the photoreceptor becomes -900V)
Using a chart with a writing rate of 6%, 20000 sheets were continuously printed, and images at the initial stage and after 20000 sheets were evaluated. A halftone image was output after 20,000 sheets for evaluation.
[0171]
(Example 22)
The evaluation performed in Example 21 was performed by changing the charging conditions as follows.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (peak to peak), frequency: 1.5 kHz
[0172]
(Example 23)
In Example 22, the evaluation was performed in the same manner as in Example 22 except that the thickness of the insulating tape was changed and the gap was changed to 160 μm.
[0173]
(Example 24)
In Example 23, evaluation was performed in the same manner as in Example 22 except that the thickness of the insulating tape was changed and the gap was changed to 240 μm.
The above results are shown in Table 6 together with the case of Example 14.
[0174]
[Table 6]

[0175]
(Example 25)
A photoconductor was prepared in the same manner as in Example 14 except that the support used in Example 14 was changed to an aluminum cylinder (JIS1050) having a diameter of 30 mm.
[0176]
(Example 26)
In Example 25, an aluminum cylinder (JIS 1050) 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 Example 25 without providing an undercoat layer, thereby preparing a photoreceptor. .
◎ Anodic oxide film treatment
The surface of the support was mirror polished, degreased and washed with water, then immersed in an electrolytic bath of 20 ° C. and 15 vol% sulfuric acid, and anodized film treatment was performed for 30 minutes at an electrolysis voltage of 15V. Further, after washing with water, sealing treatment was performed with a 7% nickel acetate aqueous solution (50 ° C.). Thereafter, washing with pure water was performed to obtain a support on which a 6 μm anodic oxide film was formed.
[0177]
(Comparative Example 28)
A photoconductor was prepared in the same manner as in Comparative Example 19 except that the support used in Comparative Example 19 was changed to an aluminum cylinder (JIS1050) having a diameter of 30 mm.
[0178]
(Comparative Example 29)
A photoconductor was prepared in the same manner as in Comparative Example 21, except that the support used in Comparative Example 21 was changed to an aluminum cylinder (JIS1050) having a diameter of 30 mm.
[0179]
The photoconductors of Examples 25 to 26 and Comparative Examples 28 to 29 produced as described above are mounted on the electrophotographic apparatus cartridge as shown in FIG. 9 and mounted on the image forming apparatus shown in FIG. The same photosensitive member is mounted on the image forming element), the image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror), and the insulation is 60 μm in thickness at both ends of the charging roller as shown in FIG. An image was output under the following charging conditions using a charging member for close placement wound with a tape (the gap between the surface of the photosensitive member and the charging member was 60 μm).
Charging conditions:
DC bias: -800V
AC bias: 2.0 kV (peak to peak), frequency: 1.8 kHz
[0180]
Under a test environment of 30 ° C.-90% RH, 10,000 sheets were continuously printed using a full color chart with a writing rate of 6%, and images at the initial stage and after 10,000 sheets were evaluated. In the image evaluation, a white solid image was output at the initial stage and after 10,000 sheets, and the background stain was evaluated. Further, the color reproducibility after 10,000 sheets was evaluated using a chart for evaluating color reproducibility. The results are shown in Table 7.
[0181]
[Table 7]

Dirt rank:
5: Almost no soiling,
4: Slightly,
3: Actual use limit level,
2 or less: Level that cannot withstand actual use
[0182]
Finally, 7.3 ° which is the lowest angle peak of the Bragg angle 2θ, which is a feature of the titanyl phthalocyanine crystal of the present invention, will be verified as to whether it is the same as the lowest angle 7.5 ° of a known material.
[0183]
Measurement example 1
Similar to the pigment described in JP-A-61-239248 (having a maximum diffraction peak at 7.5 °) obtained by the first crystal conversion in Example 1 (minimum angle 7.3 °). 3% by weight of the prepared product was added and mixed in a mortar, and the X-ray diffraction spectrum was measured as before. The X-ray diffraction spectrum of Measurement Example 1 is shown in FIG.
[0184]
Measurement example 2
A pigment prepared in the same manner as the pigment described in JP-A No. 61-239248 (having a maximum diffraction peak at 7.5 °) was used for the pigment obtained in the previous Comparative Example 4 (minimum angle 7.5 °). 3% by weight was added and mixed in a mortar, and the X-ray diffraction spectrum was measured as before. The X-ray diffraction spectrum of Measurement Example 2 is shown in FIG.
[0185]
In the spectrum of FIG. 15, it can be seen that there are two independent peaks at 7.3 ° and 7.5 ° on the low angle side, and at least the peaks at 7.3 ° and 7.5 ° are different. . On the other hand, in the spectrum of FIG. 16, 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 minimum angle peak of 7.3 ° in the titanyl phthalocyanine crystal of the present invention is different from the 7.5 ° peak in the known titanyl phthalocyanine crystal.
[0186]
【The invention's effect】
As described above, as is clear from the detailed and specific description, according to the present invention, a method for producing a dispersible organic pigment without changing the crystal form (high crystal stability) is provided for producing a dispersion. . By using this, a dispersion having a fine particle size is provided while maintaining a specific crystal form. This dispersion is very useful as a dispersion for an electrophotographic photoreceptor, and can provide a photoreceptor having specific photoreceptor characteristics and few coating film defects. As a result, a photoreceptor having stable electrostatic characteristics and high wear resistance under various environments is provided. Furthermore, there are provided a stable electrophotographic apparatus and a process cartridge for an electrophotographic apparatus that are less likely to be deteriorated in chargeability even by repeated use without losing high sensitivity.
[Brief description of the drawings]
FIG. 1 is an electron micrograph showing the particle state of a preferred amorphous titanyl phthalocyanine of the present invention.
FIG. 2 is an electron micrograph of titanyl phthalocyanine after crystal conversion according to the present invention.
FIG. 3 is another electron micrograph of titanyl phthalocyanine after crystal conversion according to the present invention.
FIG. 4 is a cross-sectional view illustrating a configuration example of an electrophotographic photosensitive member used in the present invention.
FIG. 5 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention.
FIG. 6 is a schematic view for explaining an electrophotographic process and an electrophotographic apparatus of the present invention.
FIG. 7 is a schematic view showing a proximity charging mechanism (a gap holding mechanism is formed on the charging member side).
FIG. 8 is a schematic view showing another example of the electrophotographic process of the present invention.
FIG. 9 is a schematic view showing an example of an electrophotographic process cartridge of the present invention.
FIG. 10 is another schematic diagram for explaining the tandem full-color electrophotographic apparatus of the present invention.
FIG. 11 is a diagram showing an X-ray diffraction spectrum of a dry powder of water paste.
12 is a graph showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Example 2. FIG.
13 is a view showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Comparative Example 3. FIG.
14 is an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Comparative Example 4. FIG.
15 is a graph showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Measurement Example 1. FIG.
16 is a diagram showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Measurement Example 2. FIG.
[Explanation of symbols]
1C, 1M, 1Y, 1K ......... Drum-shaped photoconductor
2C, 2M, 2Y, 2K ......... Charging member
3C, 3M, 3Y, 3K ......... Laser light
4C, 4M, 4Y, 4K ......... Developing member
5C, 5M, 5Y, 5K ......... Cleaning member
6C, 6M, 6Y, 6K ......... Image forming elements
7: Transfer paper
8: Feed roller
9 ... Registration roller
10 ... Transfer belt
11C, 11M, 11Y, 11K ... Transfer brush
12: Fixing device
21 ……… Photoconductor
22 ......... Charging lamp
23 ……… Charging member
25 .... Image exposure section
26 .... Development unit
27 ... …… Pre-transfer charger
28 .... Registration roller
29 ... Transfer paper
30 ... Transcription charger
31 ... …… Separate charger
32 …… Separated nails
33 ……… Pre-cleaning charger
34 ... Fur brush
35 ......... Blade
41... Conductive support
45 .... Charge generation layer
47 .... Charge transport layer
49 ……… Protective layer
50 ……… Photoconductor
51 .... Charging roller
52 .... Gap forming member
53 .... Metal shaft
54... Image forming area
55 .... Non-image forming area
61 ……… Photoconductor
62a ..... Driving roller
62b .... Drive roller
63 ……… Charging Charger
64 ... …… Image exposure source
65 ……… Transcription Charger
66 ... …… Pre-cleaning exposure
67 ... Cleaning brush
68 ……… Static elimination light source
76 ... …… Photoconductor
77 ……… Charging Charger
78 ……… Cleaning brush
79 ……… Image exposure section
80 ... Developing roller

Claims (19)

  The diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα has a maximum diffraction peak at least 27.2 °, and further 9.4 ° and 9.6 °. The main peak at 24.0 ° and the lowest diffraction peak at 7.3 ° with a peak between the 7.3 ° peak and the 9.4 ° peak. A titanyl phthalocyanine crystal having no peak, having a peak at 26.3 °, and having an average primary particle size of 0.2 μm or less. As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα, it has a maximum diffraction peak at 7.0 to 7.5 °, and the half-value width of the diffraction peak Amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having an average primary particle size of 0.1 μm or less in the presence of water in the presence of water, tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, , 1,2-trichloroethane is used to perform crystal conversion with one organic solvent selected from the above organic solvents before the average size of primary particles after crystal conversion grows to 0.2 μm or more. The titanyl phthalocyanine according to claim 1, wherein the titanyl phthalocyanine is separated, filtered, dried, and further subjected to a crystal conversion treatment. A method for producing talocyanine crystals. The titanyl phthalocyanine according to claim 2 , wherein the second crystal conversion treatment is treatment with one organic solvent selected from toluene, xylene, acetone, 2-butanone, methylene chloride, chloroform, and tetrahydrofuran. Crystal production method. The method for producing a titanyl phthalocyanine Z crystal according to claim 2 , wherein the second crystal conversion treatment is a treatment of applying a mechanical shearing force. An electrophotographic photoreceptor comprising at least a charge generation layer and a charge transport layer laminated on a conductive support, wherein the charge generation layer contains the titanyl phthalocyanine crystal according to claim 1. Photoconductor. 6. The electrophotographic photosensitive member according to claim 5 , wherein the charge transport layer contains a polymer charge transport material. The electrophotographic photosensitive member according to claim 6 , wherein a protective layer is laminated on the charge transport layer. The electrophotographic photosensitive member according to claim 7 , wherein the protective layer contains an inorganic pigment or metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic photoreceptor according to claim 8 , wherein the metal oxide is any one of alumina, titanium oxide, and silica having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic photosensitive member according to claim 9 , wherein the metal oxide is α-alumina having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic photosensitive member according to claim 6, wherein the protective layer contains a polymer charge transport material. The electrophotographic photosensitive member according to claim 5, wherein the surface of the electroconductive support of the electrophotographic photosensitive member is anodized. 13. In an image forming method in which at least charging, image exposure, development, and transfer are repeated on an electrophotographic photosensitive member, the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 5 to 12. Image forming method. 13. An image forming apparatus comprising an image forming element comprising at least a charging means, an image exposing means, a developing means, a transferring means and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is defined in claim 5 . An image forming apparatus comprising the electrophotographic photosensitive member according to any one of the above. The image forming apparatus according to claim 14 , wherein a plurality of the image forming elements are arranged. The image forming apparatus according to claim 14 , wherein the charging unit is a member in which a charging member is disposed in contact with or close to the photosensitive member. The image forming apparatus according to claim 16 , wherein a gap between the charging member and the photosensitive member is 200 μm or less. 18. The image forming apparatus according to claim 16, wherein the charging unit superimposes an alternating current component on a direct current component to charge the photosensitive member. A process cartridge for an image forming apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 5 to 12. Process cartridge for equipment.

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