JP4079356B2 - Dispersion preparation method, electrophotographic photosensitive member, 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される２価基を表わす。
【００６２】
【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、
【００６３】
【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）
【００６４】
【化４】

式中、Ｒ_７，Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１，Ａｒ_２，Ａｒ_３は同一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。
【００６５】
【化５】

式中、Ｒ_９，Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４，Ａｒ_５，Ａｒ_６は同一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。
【００６６】
【化６】

式中、Ｒ_１１，Ｒ_１２は置換もしくは無置換のアリール基、Ａｒ_７，Ａｒ_８，Ａｒ_９は同一又は異なるアリレン基、ｐは１〜５の整数を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。
【００６７】
【化７】

式中、Ｒ_１３，Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０，Ａｒ_１１，Ａｒ_１２は同一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。
【００６８】
【化８】

式中、Ｒ_１５，Ｒ_１６，Ｒ_１７，Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３，Ａｒ_１４，Ａｒ_１５，Ａｒ_１６は同一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。
【００６９】
【化９】

式中、Ｒ_１９，Ｒ_２０は水素原子、置換もしくは無置換のアリール基を表わし、Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７，Ａｒ_１８，Ａｒ_１９は同一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。
【００７０】
【化１０】

式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０，Ａｒ_２１，Ａｒ_２２，Ａｒ_２３は同一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。
【００７１】
【化１１】

式中、Ｒ_２２，Ｒ_２３，Ｒ_２４，Ｒ_２５は置換もしくは無置換のアリール基、Ａｒ_２４，Ａｒ_２５，Ａｒ_２６，Ａｒ_２７，Ａｒ_２８は同一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。
【００７２】
【化１２】

式中、Ｒ_２６，Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９，Ａｒ_３０，Ａｒ_３１は同一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。
【００７３】
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。
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。
【００７４】
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。
【００７５】
本発明において電荷輸送層（３７）中に可塑剤やレベリング剤を添加してもよい。可塑剤としては、ジブチルフタレート、ジオクチルフタレートなど一般の樹脂の可塑剤として使用されているものがそのまま使用でき、その使用量は、結着樹脂に対して０〜３０重量％程度が適当である。レベリング剤としては、ジメチルシリコーンオイル、メチルフェニルシリコーンオイルなどのシリコーンオイル類や、側鎖にパーフルオロアルキル基を有するポリマーあるいは、オリゴマーが使用され、その使用量は結着樹脂に対して、０〜１重量％が適当である。
【００７６】
結着樹脂としては、先に電荷輸送層（３７）で挙げた結着樹脂をそのまま用いるほかに、分散液の作製方法のところ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。
【００７７】
本発明の電子写真感光体には、導電性支持体（３１）と感光層との間に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。
【００７８】
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。
【００７９】
本発明の電子写真感光体には、感光層保護の目的で、保護層が感光層の上に設けられることもある。保護層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。保護層にはその他、耐摩耗性を向上する目的でポリテトラフルオロエチレンのような弗素樹脂、シリコーン樹脂、及びこれらの樹脂に酸化チタン、酸化錫、チタン酸カリウム等の無機材料を分散したもの等を添加することができる。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、以上のほかに真空薄膜作成法にて形成したａ−Ｃ、ａ−ＳｉＣなど公知の材料を保護層として用いることができる。
【００８０】
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。
【００８１】
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５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５において、感光体（４１）は導電性支持体上に特定の分散条件により分散された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（４３）、転写前チャージャー（４６）、転写チャージャー（４９）、分離チャージャー（５０）、クリーニング前チャージャー（５２）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（４１）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。
【００８２】
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。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帯電器とは区別されるものである。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。
【００８３】
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６に示す。
【００８４】
転写手段には、一般に上記の帯電器が使用できるが、図５に示されるように転写チャージャー（４９）と分離チャージャー（５０）を併用したものが効果的である。
また、画像露光部（４４）の光源にはＬＤもしくはＬＥＤが用いられる。除電ランプ（４２）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５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。
【００８５】
さて、現像ユニット（４５）により感光体（４１）上に現像されたトナーは、転写紙（４８）に転写されるが、全部が転写されるわけではなく、感光体（４１）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（５３）およびブレード（５４）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。
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。
【００８６】
図７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（２１）は導電性支持体上に、特定の分散条件により分散された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（２２ａ，２２ｂ）により駆動され、帯電器（２３）による帯電、光源（２４）による像露光、現像（図示せず）、帯電器（２５）を用いる転写、光源（２６）によるクリーニング前露光、ブラシ（２７）によるクリーニング、光源（２８）による除電が繰返し行なわれる。図７においては、感光体（２１）（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（２４）は、ＬＤもしくはＬＥＤが好ましく用いられる。
【００８７】
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５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。
【００８８】
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８に示すものが挙げられる。感光体（１６）は導電性支持体上に特定の分散条件により分散された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。
【００８９】
図９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９において、（１Ｃ，１Ｍ，１Ｙ，１Ｋ）はドラム状の感光体であり、この感光体（１Ｃ，１Ｍ，１Ｙ，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，２Ｋ）、現像部材（４Ｃ，４Ｍ，４Ｙ，４Ｋ）、クリーニング部材（５Ｃ，５Ｍ，５Ｙ，５Ｋ）が配置されている。帯電部材（２Ｃ，２Ｍ，２Ｙ，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，２Ｋ）と現像部材（４Ｃ，４Ｍ，４Ｙ，４Ｋ）の間の感光体裏面側より、図示しない露光部材からのレーザー光（３Ｃ，３Ｍ，３Ｙ，３Ｋ）が照射され、感光体（１Ｃ，１Ｍ，１Ｙ，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，１Ｋ）を中心とした４つの画像形成要素（６Ｃ，６Ｍ，６Ｙ，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，６Ｋ）の現像部材（４Ｃ，４Ｍ，４Ｙ，４Ｋ）とクリーニング部材（５Ｃ，５Ｍ，５Ｙ，５Ｋ）の間で感光体（１Ｃ，１Ｍ，１Ｙ，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，１１Ｋ）が配置されている。各画像形成要素（６Ｃ，６Ｍ，６Ｙ，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。
【００９０】
図９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，６Ｋ）において、感光体（１Ｃ，１Ｍ，１Ｙ，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，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，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，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，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，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，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，１１Ｋ）に印加された転写バイアスと感光体（１Ｃ，１Ｍ，１Ｙ，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，１Ｋ）上に残った残留トナーは、クリーニング装置（５Ｃ，５Ｍ，５Ｙ，５Ｋ）で回収される。なお、図９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９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。
【００９１】
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、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。
【００９２】
【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。
【００９３】
（顔料作製例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、室温下で撹拌し、ペーストの濃紺色の色が淡い青色に変化したら、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。乾燥後、チタニルフタロシアニン結晶を市販のミキサーにて祖粉砕を行ない、およそ１５０μｍ程度の細かい粉にした。これを顔料１とする。
【００９４】
顔料作製例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、顔料作製例１で得られたチタニルフタロシアニン結晶（顔料１）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
【００９５】
水ペーストの乾燥粉末のＸ線回折スペクトルを図１０に、顔料１のＸ線回折スペクトルを図１１に示す。
図１１より、顔料１は、２７．２゜に最大回折ピークを有し、更に９．４゜、９．６゜、２４．０゜に主要なピークを有し、かつ最も低角側の回折ピークとして７．３゜にピークを有し、７．４〜９．４゜の範囲にピークを有さず、また２６．３゜にピークを有さない結晶型を有するチタニルフタロシアニン結晶であることが判る。
【００９６】
（実施例１）
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）。
顔料作製例１で作製したチタニルフタロシアニン結晶 ２４０部
（顔料１）
ポリビニルブチラール １６０部
（積水化学製：ＢＸ−１）
２−ブタノン ３６００部
【００９７】
市販のビーズミル分散機（ＶＭＡ−ＧＥＴＺＭＡＮＮ ＧＭＢＨ製：ＤＩＳＰＥＲＭＡＴ ＳＬ、ローターの直径は５０ｍｍ、分散室容量は１２５ｍｌ）に直径０．５ｍｍのジルコニアボールを用い、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３０００（回転／分）にて、３００分間分散を行なった（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、５９７１３である）。
分散終了後、ビーズミル分散機よりミルベースを払い出し、更に１０３００ｇの２−ブタノンを投入し、希釈と同時に分散機に残ったミルベースをすべて払い出し、分散液を作製した。
【００９８】
（実施例２）
実施例１の分散液作製条件のうち、ローター回転数を１０００（回転／分）に変更し、更に分散時間を５００分とした以外は、実施例１と同様に分散液を作製した（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、３３１７４である）。これを分散液２とする。
【００９９】
（実施例３）
実施例１の分散液作製条件のうち、ローター回転数を５０００（回転／分）に変更し、更に分散時間を２００分とした以外は、実施例１と同様に分散液を作製した（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、６６３４８である）。これを分散液３とする。
【０１００】
（比較例１）
実施例１の分散液作製条件のうち、ローター回転数を１０００（回転／分）に変更した以外は、実施例１と同様に分散液を作製した（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、１９００４である）。これを分散液４とする。
【０１０１】
（比較例２）
実施例１の分散液作製条件のうち、ローター回転数を５０００（回転／分）に変更した以外は、実施例１と同様に分散液を作製した（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、９９５２２である）。これを分散液５とする。
【０１０２】
（比較例３）
実施例１の分散液作製条件のうち、分散時間を１５０分に変更した以外は、実施例１と同様に分散液を作製した（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、２９８５７である）。これを分散液６とする。
【０１０３】
（実施例４）
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７とする）。
顔料作製例１で作製したチタニルフタロシアニン結晶 ３６０部
（顔料１）
ポリビニルブチラール ２４０部
（積水化学製：ＢＸ−１）
２−ブタノン ５４００部
【０１０４】
市販のビーズミル分散機（ＶＭＡ−ＧＥＴＺＭＡＮＮ ＧＭＢＨ製：ＤＩＳＰＥＲＭＡＴ ＳＬ、ローターの直径は５０ｍｍ、分散室容量は１２５ｍｌ）に直径０．５ｍｍのジルコニアボールを用い、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１０００（回転／分）にて、７５０分間分散を行なった（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、３３１７４である）。
分散終了後、ビーズミル分散機よりミルベースを払い出し、更に１５４５０ｇの２−ブタノンを投入し、希釈と同時に分散機に残ったミルベースをすべて払い出し、分散液を作製した。
【０１０５】
（実施例５）
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８とする）。
顔料作製例１で作製したチタニルフタロシアニン結晶 ４８部
（顔料１）
ポリビニルブチラール ３２部
（積水化学製：ＢＸ−１）
２−ブタノン ７２０部
【０１０６】
市販のビーズミル分散機（ＶＭＡ−ＧＥＴＺＭＡＮＮ ＧＭＢＨ製：ＤＩＳＰＥＲＭＡＴ ＳＬ、ローターの直径は５０ｍｍ、分散室容量は１２５ｍｌ）に直径０．５ｍｍのジルコニアボールを用い、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３０００（回転／分）にて、６０分間分散を行なった（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、５９７１３である）。
分散終了後、ビーズミル分散機よりミルベースを払い出し、更に２０６０ｇの２−ブタノンを投入し、希釈と同時に分散機に残ったミルベースをすべて払い出し、分散液を作製した。
【０１０７】
（比較例４）
実施例５の分散液作製条件のうち、分散時間を３０分に変更した以外は、実施例４と同様に分散液を作製した（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、２９８５７である）。これを分散液９とする。
【０１０８】
（比較例５）
実施例５の分散液作製条件のうち、分散時間を１２０分に変更した以外は、実施例４と同様に分散液を作製した（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、１１９４２７である）。これを分散液１０とする。
【０１０９】
（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１１とする）。
顔料作製例１で作製したチタニルフタロシアニン結晶 １２０部
（顔料１）
ポリビニルブチラール ８０部
（積水化学製：ＢＸ−１）
２−ブタノン １８００部
【０１１０】
市販のビーズミル分散機（ＶＭＡ−ＧＥＴＺＭＡＮＮ ＧＭＢＨ製：ＤＩＳＰＥＲＭＡＴ ＳＬ、ローターの直径は５０ｍｍ、分散室容量は１２５ｍｌ）に直径０．５ｍｍのジルコニアボールを用い、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３０００（回転／分）にて、１５０分間分散を行なった（チタニルフタロシアニン結晶１ｇあたりの分散ストレスは、５９７１３である）。
分散終了後、ビーズミル分散機よりミルベースを払い出し、更に５１５０ｇの２−ブタノンを投入し、希釈と同時に分散機に残ったミルベースをすべて払い出し、分散液を作製した。
【０１１１】
（実施例７）
実施例１の分散液作製条件において、使用したジルコニアボールを、直径０．３ｍｍのものに変更した以外は、実施例１と同様に分散液を作製した（これを分散液１２とする）。
【０１１２】
（比較例６）
実施例１の分散液作製条件において、使用したジルコニアボールを、直径０．８ｍｍのものに変更した以外は、実施例１と同様に分散液を作製した（これを分散液１３とする）。
【０１１３】
（比較例７）
実施例１で使用した分散装置の分散室を容量５００ｍｌ（ローター径は７５ｍｍ）のものに変更し、その他の分散条件は同様にして分散液を作製した（これを分散液１４とする）。
【０１１４】
（比較例８）
実施例２で使用した分散装置の分散室を容量５００ｍｌ（ローター径は７５ｍｍ）のものに変更し、分散時間を３３３分に変更した以外は、実施例２と同様に分散液を作製した（これを分散液１５とする）。
【０１１５】
以上のように作製した分散液１〜１５は、以下の評価を行なった。結果を表１に示す。
平均粒径 堀場製作所：ＣＡＰＡ７００にて体積平均粒径を評価した。
粗大粒子の観察 分散液をスライドガラスに塗布し、観察用のサンプルを作製した。
続いて、市販の光学顕微鏡（５０〜１００倍）にて、塗膜の観察を行なった。
Ｘ線回折スペクトル 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。
成膜性の評価 分散液を洗浄したアルミ板に浸漬塗工法により成膜して、塗膜の状態を観察した。
【０１１６】
【表１】

【０１１７】
表１から判るように、顔料（チタニルフタロシアニン結晶）１ｇあたりの分散ストレスを適正範囲（３２０００〜９５０００）にすることによって、分散安定性が高く（平均粒径が細かく、顕微鏡レベルで観察しても粗大粒子が認められない）、かつ結晶安定性が高い（分散前と同じ結晶型を維持している）状態で、分散液が形成される。このような分散液を使用することにより、良好な塗膜が形成される。
各種条件においても平均粒径は大きな変化を見せず、ここまでに評価されてきた平均粒径だけでは、分散液の分散安定性は表わし尽くせないことも判る。
また、分散エネルギー量が適正な場合においても、メディア径が０．５ｍｍより大きい場合には分散安定性に劣り、顕微鏡レベルで観察される粗大粒子が残存し、これを用いて成膜した場合に悪影響を与えている。
また、ローター径が大きい場合には、分散が不安定になりやすく、分散ストレスが適正な場合においても、結晶転移が観測されたり、粗大粒子が観測されたりした。このことは、結晶安定性と分散安定性の両立が難しいことを示している。
【０１１８】
分散溶媒量と分散室容量の関係に関しては、５０：１よりも大きい場合においては、適正な分散ストレスを与えることにより、良好な分散液を作製することができるが、分散時間が極めて長くなってしまう。また、１０：１よりも小さい場合には逆に適正分散エネルギー量を設定するためには、分散時間が短くなりすぎて、分散安定性がわずかに劣る場合がある。
【０１１９】
なお、結晶の一部が結晶転移してしまった場合（比較例２）のＸ線回折スペクトルを図１２に示す。図中の矢印が、図１１の結晶には認められない新たなピーク（２６．３゜）である。
【０１２０】
【化１３】

【０１２１】
（実施例８）
実施例１の分散液に使用した溶媒を、２−ブタノンからｎ−酢酸ブチルに変更した以外は、実施例１と同様に分散液を作製した（これを分散液１６とする）。
【０１２２】
（実施例９）
実施例１の分散液に使用した溶媒を、２−ブタノンからｎ−ブタノールに変更した以外は、実施例１と同様に分散液を作製した（これを分散液１７とする）。
【０１２３】
（実施例１０）
実施例１の分散液の組成を下記組成のものに変更した以外は、実施例１と同様に分散液を作製した（これを分散液１８とする）。
顔料作製例１で作製したチタニルフタロシアニン結晶 ２４０部
（顔料１）
ポリビニルブチラール １６０部
（積水化学製：ＢＸ−１）
テトラヒドロフラン ３６００部
イオン交換水 ３６部
【０１２４】
（実施例１１）
実施例１０の分散液より、イオン交換水を除いた以外は、実施例１０と同様に分散液を作製した（これを分散液１９とする）。
【０１２５】
（実施例１２）
実施例１の分散液より、ポリビニルブチラールを除いた以外は、実施例１と同様に分散液を作製した（これを分散液２０とする）。
以上のように作製した分散液１６〜２０を、分散液１〜１５の場合と同様に評価を行なった。実施例１の結果と併せて表２に示す。
【０１２６】
【表２】

表２から判るように、分散溶媒として２−ブタノン（ケトン系溶媒）、ｎ−酢酸ブチル（エステル系溶媒）、テトラヒドロフラン（エーテル系溶媒）を用いた場合には良好な特性を有する分散液が得られたが、その他の溶媒であるｎ−ブタノール（アルコール系溶媒）を用いた場合には、やや分散安定性に劣る結果となった。
また、イオン交換水を添加しない場合や、バインダー樹脂を添加しない場合においては、結晶安定性に劣る場合が認められた。
【０１２７】
（顔料作製例２）
特開平１−２９９８７４号（特許第２５１２０８１号）公報、実施例１に記載の方法に準じて、顔料を作製した。すなわち、先の顔料作製例１で作製したウェットケーキを乾燥し、乾燥物２００ｇをポリエチレングリコール１０００ｇに加え、２００００ｇのガラスビーズと共に、サンドミルを行なった。結晶転移後、希硫酸、水酸化アンモニウム水溶液で順次洗浄し、乾燥して顔料を得た（これを顔料２とする）。
【０１２８】
（顔料作製例３）
特開平３−２６９０６４号（特許第２５８４６８２号）公報、製造例１に記載の方法に準じて、顔料を作製した。すなわち、先の顔料作製例１で作製したウェットケーキを乾燥し、乾燥物２００ｇをイオン交換水２０００ｇとモノクロルベンゼン２００ｇ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３とする）。
【０１２９】
（顔料作製例４）
特開平２−８２５６号（特公平７−９１４８６号）公報の製造例に記載の方法に準じて、顔料を作製した。すなわち、フタロジニトリル１９６ｇと１−クロロナフタレン１５００ｍｌを撹拌混合し、窒素気流下で四塩化チタン４４ｍｌを滴下する。滴下終了後、徐々に２００℃まで昇温し、反応温度を２００℃〜２２０℃の間に保ちながら３時間撹拌して反応を行なった。反応終了後、放冷し１３０℃になったところ熱時ろ過し、次いで１−クロロナフタレンで粉体が青色になるまで洗浄、次にメタノールで数回洗浄し、更に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４とする）。
【０１３０】
（顔料作製例５）
特開昭６４−１７０６６号（特公平７−９７２２１号）公報、合成例１に記載の方法に準じて、顔料を作製した。すなわち、α型ＴｉＯＰｃ２００部を食塩４００ｇおよびアセトフェノン２００ｇと共にサンドグラインダーにて１００℃にて１０時間結晶変換処理を行なった。これをイオン交換水及びメタノールで洗浄し、希硫酸水溶液で精製し、イオン交換水で酸分がなくなるまで洗浄した後、乾燥して顔料を得た（これを顔料５とする）。
【０１３１】
（顔料作製例６）
特開平１１−５９１９号（特許第３００３６６４号）公報、実施例１に記載の方法に準じて、顔料を作製した。すなわち、Ｏ−フタロジニトリル２０４部、四塩化チタン部７６部をキノリン５００部中で２００℃にて２時間加熱反応後、水蒸気蒸留で溶媒を除き、２％塩化水溶液、続いて２％水酸化ナトリウム水溶液で精製し、メタノール、Ｎ，Ｎ−ジメチルホルムアミドで洗浄後、乾燥し、チタニルフタロシアニンを得た。このチタニルフタロシアニン２００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８０００部の氷水中に、ゆっくりと注入し、析出した結晶を濾過する。結晶を酸が残量しなくなるまで蒸留水で洗浄し、ウエットケーキを得る。そのケーキをＴＨＦ１００００部中で約５時間攪拌を行ない、ろ過、ＴＨＦによる洗浄を行ない乾燥後、顔料を得た（これを顔料６とする）。
【０１３２】
（顔料作製例７）
特開平３−２５５４５６号（特許第３００５０５２号）公報、合成例２に記載の方法に準じて、顔料を作製した。すなわち、先の顔料作製例１で作製したウェットケーキ４００部を塩化ナトリウム６００部とジエチレングリコール２８０部に混合し、８０℃の加熱下で自動乳鉢により６０時間ミリング処理を行なった。次に、この処理品に含まれる塩化ナトリウムとジエチレングリコールを完全に除去するために充分な水洗を行なった。これを減圧乾燥した後にシクロヘキサノン８０００部と直径１ｍｍのガラスビーズを加えて、３０分間サンドミルにより処理を行ない、顔料を得た（これを顔料７とする）。
【０１３３】
以上の顔料作製例２〜７で作製した顔料は、先程と同様の方法でＸ線回折スペクトルを測定し、それぞれの公報に記載のスペクトルと同様であることを確認した。表３にそれぞれのＸ線回折スペクトルと顔料作製例１で得られた顔料のＸ線回折スペクトルのピーク位置の特徴を示す。
【０１３４】
【表３】

【０１３５】
（実施例１３）
実施例６で使用したチタニルフタロシアニン結晶（顔料１）の代わりに、それぞれ顔料２を用いた以外は、実施例６と同様に分散液を作製した（これらを分散液２１とする）。
【０１３６】
（実施例１４）
実施例６で使用したチタニルフタロシアニン結晶（顔料１）の代わりに、それぞれ顔料３を用いた以外は、実施例６と同様に分散液を作製した（これらを分散液２２とする）。
【０１３７】
（実施例１５）
実施例６で使用したチタニルフタロシアニン結晶（顔料１）の代わりに、それぞれ顔料４を用いた以外は、実施例６と同様に分散液を作製した（これらを分散液２３とする）。
【０１３８】
（実施例１６）
実施例６で使用したチタニルフタロシアニン結晶（顔料１）の代わりに、それぞれ顔料５を用いた以外は、実施例６と同様に分散液を作製した（これらを分散液２４とする）。
【０１３９】
（実施例１７）
実施例６で使用したチタニルフタロシアニン結晶（顔料１）の代わりに、それぞれ顔料６を用いた以外は、実施例６と同様に分散液を作製した（これらを分散液２５とする）。
【０１４０】
（実施例１８）
実施例６で使用したチタニルフタロシアニン結晶（顔料１）の代わりに、それぞれ顔料７を用いた以外は、実施例６と同様に分散液を作製した（これらを分散液２６とする）。
【０１４１】
以上のように作製した分散液２１〜２６は、実施例６の場合と同様に評価し、実施例６の結果と併せて表４に示す。
【０１４２】
【表４】

表４から判るように、顔料１とは結晶型の異なるチタニルフタロシアニン結晶を用いた場合においても、適正な分散ストレスを与えて分散を行なうことにより、結晶転移を起こさず、粗大粒子のない分散安定性の高い分散液を作製することができた。
【０１４３】
＜感光体の作製＞
（感光体作製例１）
直径６０ｍｍのアルミニウムシリンダー（ＪＩＳ１０５０）に、下記組成の下引き層塗工液、電荷発生層塗工液、および電荷輸送層塗工液を、順次塗布・乾燥し、３．５μｍの下引き層、０．２μｍの電荷発生層、１９μｍの電荷輸送層を形成し、積層感光体を作製した（これを感光体１とする）。
【０１４４】
◎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
【０１４５】
◎電荷発生層塗工液
先述の分散液１を用いた。
【０１４６】
◎電荷輸送層塗工液
ポリカーボネート（ユーピロンＺ３００：三菱ガス化学社製） １０部
下記構造式の電荷輸送物質 ７部
【０１４７】
【化１４】

テトラヒドロフラン ８０部
【０１４８】
（感光体作製例２）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体２とする）。
【０１４９】
（感光体作製例３）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体３とする）。
【０１５０】
（感光体作製例４）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体４とする）。
【０１５１】
（感光体作製例５）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体５とする）。
【０１５２】
（感光体作製例６）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体６とする）。
【０１５３】
（感光体作製例７）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体７とする）。
【０１５４】
（感光体作製例８）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体８とする）。
【０１５５】
（感光体作製例９）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体９とする）。
【０１５６】
（感光体作製例１０）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体１０とする）。
【０１５７】
（感光体作製例１１）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体１１とする）。
【０１５８】
（感光体作製例１２）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体１２とする）。
【０１５９】
（感光体作製例１３）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体１３とする）。
【０１６０】
（感光体作製例１４）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体１４とする）。
【０１６１】
（感光体作製例１５）
感光体作製例１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１５を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体１５とする）。
【０１６２】
（感光体作製例１６）
感光体作製例１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１６を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体１６とする）。
【０１６３】
（感光体作製例１７）
感光体作製例１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１７を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体１７とする）。
【０１６４】
（感光体作製例１８）
感光体作製例１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１８を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体１８とする）。
【０１６５】
（感光体作製例１９）
感光体作製例１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１９を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体１９とする）。
【０１６６】
（感光体作製例２０）
感光体作製例１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２０を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体２０とする）。
【０１６７】
（感光体作製例２１）
感光体作製例１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２１を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体２１とする）。
【０１６８】
（感光体作製例２２）
感光体作製例１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２２を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体２２とする）。
【０１６９】
（感光体作製例２３）
感光体作製例１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２３を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体２３とする）。
【０１７０】
（感光体作製例２４）
感光体作製１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２４を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体２４とする）。
【０１７１】
（感光体作製例２５）
感光体作製例１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２５を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体２５とする）。
【０１７２】
（感光体作製例２６）
感光体作製例１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２６を用いた以外は、感光体作製例１と同様に感光体を作製した（これを感光体２６とする）。
【０１７３】
（実施例１９〜３６および比較例９〜１６）
以上のように作製した感光体１〜２６を市販の普通紙複写機（リコー製：ｉｍａｇｉｏＭＦ４５５０）に搭載した。ＡＣ電源として複写機本体外に別の電源を用意した。
画像露光光源は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）とした。
帯電部材としては、図６に示すような非接触近接配置方式の帯電ローラー（両端の非画像部には、厚さ５０μｍの絶縁テープを巻き付け、感光体表面と帯電ローラー表面の間に、５０μｍの空隙を有するように配置した）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：−９００Ｖ
ＡＣバイアス：２．３ｋＶ（peak to peak）、周波数２ｋＨｚ
書き込み率６％のチャートを用い、連続して５０００枚の印刷を行ない、初期及び５０００枚後の画像を評価した。画像評価は、初期及び５０００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、４隅および中央に直径１ｃｍの黒丸（黒ベタ）を含むハーフトーン画像を初期及び５０００枚後に出力し画像評価を行なった。結果を表５に示す。
【０１７４】
【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
【０１７５】
（感光体作製例２７）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体２７とする）。
【０１７６】
◎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１４００００）
【０１７７】
【化１５】

下記構造の添加剤 ０．５部
【０１７８】
【化１６】

テトラヒドロフラン １００部
【０１７９】
（感光体作製例２８）
感光体作製例１における電荷輸送層の膜厚を１７μｍ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、２μｍの保護層を設けた以外は感光体作製例１と同様に感光体を作製した（これを感光体２８とする）。
【０１８０】
◎保護層塗工液
ポリカーボネート（ユーピロンＺ３００：三菱ガス化学社製） １０部
下記構造式の電荷輸送物質 ７部
【０１８１】
【化１７】

アルミナ微粒子 ４部
（比抵抗：２．５ｘ１０^１２Ω・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
【０１８２】
（感光体作製例２９）
感光体作製例１における電荷輸送層の膜厚を１７μｍ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、２μｍの保護層を設けた以外は感光体作製例１と同様に感光体を作製した（これを感光体２９とする）。
【０１８３】
◎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１４００００）
【０１８４】
【化１８】

アルミナ微粒子 ４部
（比抵抗：２．５ｘ１０１２Ω・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
【０１８５】
（感光体作製例３０）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体３０とする）。
【０１８６】
◎電荷輸送層塗工液
ポリカーボネート（ユーピロンＺ３００：三菱ガス化学社製） １０部
下記構造式の電荷輸送物質 ７部
【０１８７】
【化１９】

トルエン ８０部
【０１８８】
（感光体作製例３１）
感光体作製例１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、感光体作製例１と同様に感光体を作製した（これを感光体３１とする）。
【０１８９】
◎電荷輸送層塗工液
ポリカーボネート（ユーピロンＺ３００：三菱ガス化学社製） １０部
下記構造式の電荷輸送物質 ７部
【０１９０】
【化２０】

塩化メチレン ８０部
【０１９１】
（感光体作製例３２）
感光体作製例１におけるアルミニウムシリンダー（ＪＩＳ１０５０）を以下の陽極酸化皮膜処理を行ない、次いで下引き層を設けずに、感光体作製例１と同様に電荷発生層、電荷輸送層を設け、感光体を作製した（これを感光体３２とする）。
【０１９２】
◎陽極酸化皮膜処理
支持体表面の鏡面研磨仕上げを行ない、脱脂洗浄、水洗浄を行なった後、液温２０℃、硫酸１５ｖｏｌ％の電解浴に浸し、電解電圧１５Ｖにて３０分間陽極酸化皮膜処理を行なった。更に、水洗浄を行なった後、７％の酢酸ニッケル水溶液（５０℃）にて封孔処理を行なった。その後純水による洗浄を経て、７μｍの陽極酸化皮膜が形成された支持体を得た。
【０１９３】
以上のように作製した感光体１、２７〜３２を市販の普通紙複写機（リコー製：ｉｍａｇｉｏＭＦ４５５０）に搭載した。ＡＣ電源として複写機本体外に別の電源を用意した。
画像露光光源は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)とした。
帯電部材としては、図６に示すような非接触近接配置方式の帯電ローラー（両端の非画像部には、厚さ５０μｍの絶縁テープを巻き付け、感光体表面と帯電ローラー表面の間に、５０μｍの空隙を有するように配置した）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：−９００Ｖ
ＡＣバイアス：２．３ｋＶ（peak to peak）、周波数２ｋＨｚ
【０１９４】
書き込み率６％のチャートを用い、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（下記ランクで評価した）。また、４隅および中央に直径１ｃｍの黒丸（黒ベタ）を含むハーフトーン画像を初期及び１００００枚後に出力し画像評価を行なった。
結果を表６に示す。
【０１９５】
【表６】

＜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
【０１９６】
（実施例４４）
実施例３７の評価において、帯電条件を以下の条件に変更した以外は、実施例３７と同様に評価を行なった。結果を表７に示す。
＜帯電条件＞
ＤＣバイアス：−１７００Ｖ
（感光体表面の未露光部電位が−９００Ｖになるように設定）
【０１９７】
（実施例４５）
実施例４４の評価において、使用する帯電ローラーを接触方式（ローラー材質等は同じであり、両端の絶縁テープを巻き付けない）に変更し、下記の帯電条件で画像を出力した。結果を表７に示す。
＜帯電条件＞
ＤＣバイアス：−１６５０Ｖ
（感光体表面の未露光部電位が−９００Ｖになるように設定）
【０１９８】
（実施例４６）
実施例４４の評価において、使用する帯電ローラーを接触方式（ローラー材質等は同じであり、両端の絶縁テープを巻き付けない）に変更し、下記の帯電条件で画像を出力した。結果を表７に示す。
＜帯電条件＞
ＤＣバイアス：−９００Ｖ
ＡＣバイアス：２．３ｋＶ（peak to peak）、周波数２ｋＨｚ
【０１９９】
（実施例４７）
実施例３７の評価において、絶縁テープの厚みを変えて、空隙を１５０μｍに変更した以外は実施例３７と同様に評価を行なった。結果を表７に示す。
【０２００】
（実施例４８）
実施例３７の評価において、絶縁テープの厚みを変えて、空隙を２５０μｍに変更した以外は実施例３７と同様に評価を行なった。結果を表７に示す。
【０２０１】
（実施例４９）
実施例３７の評価において、使用する帯電部材としてスコロトロンチャージャーを用い、評価を行なった。この際、試験に用いる複写機はスコロトロンチャージャーを搭載できるように改造を施した。帯電条件は下記の通りである。
ＤＣバイアス：−６．５ｋＶ
【０２０２】
【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
【０２０３】
（感光体作製例３３）
感光体作製例１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）に変更した以外は感光体作製例１と同様に感光体を作製した（これを感光体３３とする）。
【０２０４】
（感光体作製例３４）
感光体作製例３３において、使用した分散液１の代わりに分散液４を用いた以外は、感光体作製例３３と同様に感光体を作製した（これを感光体３４とする）。
【０２０５】
（感光体作製例３５）
感光体作製例３３において、使用した分散液１の代わりに分散液５を用いた以外は、感光体作製例３３と同様に感光体を作製した（これを感光体３５とする）。
【０２０６】
（実施例５０および比較例１７、１８）
以上のように作製した感光体３３〜３５を、図８に示すような電子写真装置用カートリッジに装着し、図９に示すようなタンデム方式のフルカラー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６に示すような帯電ローラーの両端部に厚さ５０μｍの絶縁テープを巻き付けた近接配置用の帯電部材（感光体と帯電部材表面間の空隙が５０μｍ）を用い、下記の帯電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：２．２ｋＶ（peak to peak）、周波数：１．５ｋＨｚ
【０２０７】
書き込み率６％のフルカラーチャートを用い、連続して５０００枚の印刷を行ない、初期及び５０００枚後の画像を評価した。画像評価は、初期及び５０００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、５０００枚後の色再現性を評価した。結果を表８に示す。
【０２０８】
【表８】

＜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
【０２０９】
【発明の効果】
以上、詳細且つ具体的な説明により明らかなように、本発明によれば、結晶安定性が低く、微粒子化が困難であるチタニルフタロシアニン結晶の分散に鑑み、特定の条件化（チタニルフタロシアニン結晶１ｇあたりの分散ストレスを所定範囲にする）で分散を行なうことにより、結晶安定性と微粒子化のトレード・オフの関係を解消することができた。この結果、結晶安定性が高く（結晶転移の少ない）、粒子サイズの小さなチタニルフタロシアニン結晶を含む分散液の製造方法が提供される。この分散液は、保存安定性にも富み、成膜性が良好であるだけでなく、チタニルフタロシアニン結晶特有の特性を維持したままの状態で微粒子化が施される。このため、この分散液を用いて作製される感光体は、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と残留電位の上昇を生じない安定な電子写真感光体である。また、繰り返し使用によっても異常画像の発生の少ない電子写真感光体が提供される。
更に、高速プリントが可能で、異常画像の発生の少ない、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】本発明に用いられるビーズミル分散装置の一例を示す図である。
【図２】図１における分散室（７２）の中側を示す図である。
【図３】本発明の電子写真感光体を表わす断面図である。
【図４】本発明の電子写真感光体の別の構成例を示す断面図である。
【図５】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６】帯電部材側にギャップ形成部材を配置した近接帯電機構の一例を示す図である。
【図７】本発明による電子写真プロセスの別の例を示す図である。
【図８】プロセスカートリッジの形状の一般的な例を示す図である。
【図９】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概略図である。
【図１０】顔料作製例１で得られた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１１】顔料１のＸ線回折スペクトルを示す図である。
【図１２】比較例２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 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
１６ 感光体
１７ 帯電チャージャ
１８ クリーニングブラシ
１９ 画像露光部
２０ 現像ローラ
２１ 感光体
２２ａ 駆動ローラ
２２ｂ 駆動ローラ
２３ 帯電チャージャ
２４ 像露光源
２５ 転写チャージャ
２６ クリーニング前露光
２７ クリーニングブラシ
２８ 除電光源
３１ 導電性支持体
３５ 電荷発生層
３７ 電荷輸送層
３９ 保護層
４１ 感光体
４２ 除電ランプ
４３ 帯電ローラ
４４ 画像露光部
４５ 現像ユニット
４６ 転写前チャージャ
４７ レジストローラ
４８ 転写紙
４９ 転写チャージャ
５０ 分離チャージャ
５１ 分離爪
５２ クリーニング前チャージャ
５３ ファーブラシ
５４ クリーニングブラシ
６０ 感光体
６１ 帯電ローラー
６２ ギャップ形成部材
６３ 金属シャフト
６４ 画像形成領域
６５ 非画像形成領域
７１ モーター
７２ 分散室
７３ 配管
７４ 循環タンク
７５ 循環ポンプ
７７ 配管
７８ 配管
７９ 分散室を固定する台[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a dispersion using titanyl phthalocyanine crystals.
The present invention also relates to an electrophotographic photoreceptor produced using the dispersion thus produced, an electrophotographic apparatus using the electrophotographic photoreceptor and a process cartridge for an electrophotographic apparatus.
Specifically, it is excellent in dispersibility and crystal stability, and a method for preparing a dispersion containing a titanyl phthalocyanine crystal that is easy to handle, as well as excellent stability of charging potential and residual potential even after repeated use, and abnormalities such as soiling The present invention relates to an electrophotographic photosensitive member with less image generation, an electrophotographic apparatus using the same, and a process cartridge for the 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]
In order to produce such a dispersion, various dispersers and dispersion systems have been proposed so far, and methods for increasing the dispersion efficiency have been devised (see, for example, Patent Documents 1 to 4). These are all intended to make the pigment particles as fine as possible (to reduce the particle size) by using or improving various dispersing devices and dispersion conditions. These technologies focus on how to improve the dispersion efficiency as described above in order to reduce the particle size of the pigment in the dispersion, and are extremely effective for pigments with high crystal stability. It can be said that it is a simple method.
[0004]
On the other hand, even if organic pigments are represented by the same structural formula, there are pigments having many crystal forms (crystal polymorphs). Such pigments have different molecular arrangements in crystals as an aggregate of molecules even if they have the same chemical structural formula at the molecular level. In such a case, the pigment color (absorption spectrum), particle morphology, and physical properties (characteristics) often change extremely depending on the crystal form. When the absorption spectrum and particle morphology change in this way, for example, when used as a paint, the color changes and a coating film having a desired color cannot be formed. Further, when an organic pigment is used as a functional material, if a physical property value is different, an element using the same may not exhibit a desired function.
[0005]
The titanyl phthalocyanine crystal used in the present invention is a typical polymorphic organic pigment. Among them, there are cases in which specific characteristics are exhibited only when a specific crystal form is exhibited (when it is used as a charge generation material of a photoreceptor, it exhibits a highly sensitive photocarrier generation ability). A dispersion method and conditions that maintain the mold are necessary, but there are not many examples examined. 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 an electrophotographic photoreceptor. As a charge generation material, it exhibits extremely high photocarrier generation efficiency, but since it is in a metastable state as a crystal state, it is easily transferred to another crystal type. When stress is applied to the crystal to destroy the primary particles, the crystal is easily transferred to a titanyl phthalocyanine crystal having a maximum diffraction peak at 26.3 ° as a 2θ diffraction peak. Therefore, even if a part of the crystal is transferred, if it is used as a charge generating material for a photoreceptor, problems such as a decrease in photosensitivity and an increase in residual potential during repeated use occur.
[0006]
In view of such a point, Patent Document 1 discloses a technique in which a dispersion liquid containing a titanyl phthalocyanine pigment is branched in two directions and collided to form fine particles while maintaining the crystal form. Although this method is an excellent technology, it is not possible to use a conventional dispersion method (for example, a ball mill, a bead mill, etc.) using a medium, and it introduces a new device and costs. Will result in high. Moreover, since the high-pressure dispersion liquid is collided, the dispersion liquid tends to be high in temperature, and a flammable organic solvent is generally used as the dispersion solvent, which may be dangerous. In addition, the concentration of the dispersion is likely to change with high temperature, and the molecular chain of the binder resin used in combination is easily broken. Moreover, when using a high-pressure homogenizer as described in Patent Document 2, it has the same drawbacks as described above, and is difficult to use in production.
[0007]
On the other hand, in order to prevent the above-mentioned crystal transition, in a dispersion apparatus using a conventional dispersion medium, if the dispersion condition is mild, a dispersion liquid having a large average particle diameter is produced as described above, or coarse particles are produced. A dispersion in which is left 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.
[0008]
In view of such drawbacks, Patent Document 4 discloses a dispersion method aiming at stabilization of a crystal type by specifying a dispersion time when dispersing a specific crystal type titanyl phthalocyanine crystal. However, the factor related to the crystal transition of titanyl phthalocyanine is determined not only by the dispersion time but rather by the stress applied to the crystal, and even if the dispersion time is fixed depending on the ratio of the amount of the dispersion and the scale of the dispersion chamber. The dispersion stress changes, and the optimum dispersion condition is not necessarily determined under the conditions described in Patent Document 4.
[0009]
In Patent Document 3, a dispersion liquid having a small average particle diameter can be prepared in a short time by using a spherical finely pulverized medium having a diameter of 0.4 to 0.8 mm when dispersing the organic pigment in a solvent. The effect is disclosed. Furthermore, there is a description specifying the dispersion time in addition to the above conditions (for example, see Patent Document 5). However, when a titanyl phthalocyanine crystal having a specific crystal type is used as in the present invention, not only how to reduce the particle size as described above, but also the particle size is reduced while maintaining the specific crystal type ( In other words, it is important to eliminate the trade-off between crystal stability and micronization, and the above-described known technology cannot solve the problem of the present invention.
As described above, in the dispersion of 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.
[0010]
[Patent Document 1]
JP-A-4-337362 (Claim 1, page 2, right column, lines 1 to 6)
[Patent Document 2]
Japanese Patent Laid-Open No. 5-188614 (Claims 1, 2 and 3)
[Patent Document 3]
JP-A-6-43672 (Claim 1, page 2, right column, lines 31 to 41)
[Patent Document 4]
JP-A-8-123052 (Claim 1, Claim 2, Claim 3, page 19, line 19 to right column, line 1)
[Patent Document 5]
JP 2001-290292 A (Claim 2, page 2, right column, line 50 to page 3, left column, line 5)
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a dispersion containing titanyl phthalocyanine crystals having high crystal stability (small crystal transition) and small particle size.
Another object of the present invention is to provide a stable electrophotographic photosensitive member that does not cause a decrease in chargeability and an 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 and have few 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 before the photocarrier generated by the charge generation material is transferred to the charge transport material, the probability of deactivation inside the particle increases. In addition, when the photocarrier is transferred to the charge transport material, if the pigment particles are large, the surface area is inevitably reduced, the contact amount between them is reduced, and the carrier injection efficiency is lowered. 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 image defects based on this increase in probability.
[0013]
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.
[0014]
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.
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 titanyl phthalocyanine crystal used in the present invention is a polymorphic material, and the crystal form with particularly high photocarrier generation efficiency is a diffraction peak (±±) of Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα. 0.2 °), which is only a crystal having a maximum diffraction peak at 27.2 °, and other crystal-type materials have a function as a charge generating material, but a high speed required by the current electrophotographic process. However, it does not have characteristics that satisfy the requirements of high stability, reduction in diameter of the photoreceptor, and high stability during 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 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.
(1) Excessive dispersion stress (dispersion energy) causes crystal transition to proceed
That is, in the dispersion process of the titanyl phthalocyanine crystal, when dispersing to the target particle size, it is necessary to pulverize and disperse particles larger than that, but if excessive dispersion stress is applied, Excessive energy becomes the energy of crystal transition.
(2) The temperature rise during dispersion is to advance the crystal transition.
That is, in the dispersion process of the titanyl phthalocyanine crystal, it is converted into energy that causes crystal transition even at a partial temperature rise. Therefore, a sufficient cooling mechanism is required in the part where the dispersion stress is applied to the titanyl phthalocyanine crystal in the dispersion apparatus when the temperature rise is expected.
[0018]
In consideration of the above two points, in the method of dispersing by dispersing the dispersion liquid described in JP-A-4-372955 in two directions and colliding it, the application of excessive energy is suppressed. The temperature of the dispersion is inevitable even if the entire apparatus is cooled. This shows that this method is disadvantageous. In addition, when using a high-pressure homogenizer as described in Patent Document 2, it is difficult to suppress the temperature rise of the dispersion as in the case of the previous dispersion apparatus, and this method is not a good idea. Furthermore, since conventionally used ball mill type dispersion devices rotate the pot directly, it is basically difficult to provide a cooling mechanism. Therefore, this method is also not an advantageous method.
[0019]
On the other hand, the bead mill method used in the present invention can cool the dispersion chamber itself, and it is also possible to prevent the dispersion liquid from being heated at all by controlling the size and rotation speed of the dispersion chamber. Further, by using a circulation type bead mill dispersing device as will be described later, it is possible to suppress a slight temperature rise by performing sufficient cooling in the circulation tank section. In addition, the scale can be relatively increased by this method.
From the above points, it can be said that the bead mill method is the most appropriate dispersion method as the dispersion method.
[0020]
Furthermore, the present inventors tried to analyze the pulverization / dispersion process of titanyl phthalocyanine crystal when using the bead mill method, and obtained the following knowledge.
(1) The final reached particle size after dispersion is determined by the size of the media diameter.
That is, the larger the media diameter used for dispersion, the higher the ability to grind coarse particles of titanyl phthalocyanine crystals (aggregates of primary particles). However, since a dispersion method such as a bead mill is a method that originally has a high grinding ability, it does not necessarily require the aid of the size (ie, weight) of the media. Rather, it is important how much media can be packed per predetermined volume (how small the porosity is). It was found that the smaller the porosity, the smaller the titanyl phthalocyanine particle size after dispersion. Practically, if the media diameter (outer diameter) is 0.5 mm or less, it can be used sufficiently. However, the smaller the size, the more the media wears, and the handling during cleaning becomes very complicated. For this reason, there is a lower limit, and media with an outer diameter of less than 0.1 mm should not be used.
[0021]
(2) The rotor diameter installed in the dispersion chamber has an upper limit.
The rotor diameter is proportional to the size of the dispersion chamber. The larger the rotor diameter, the larger the dispersion liquid can be produced at one time. Further, as the rotor diameter increases, the dispersion stress increases when the number of rotations of the rotor per unit time is made constant. From this fact, it is true that the larger the rotor diameter, the higher the dispersion efficiency. However, when dispersion is performed without applying dispersion stress more than necessary, if the rotor diameter is large, it is necessary to reduce the rotational speed and / or shorten the dispersion time. When the rotational speed is reduced, rotational unevenness may occur unless a motor with a very large torque is used, resulting in instability of dispersion itself, resulting in residual coarse particles or some crystal transition. Or produce. When the dispersion time is shortened, the dispersion stability is inferior. This is because the dispersion of a pigment such as titanyl phthalocyanine crystal consists of other steps, and consists of a step of pulverizing coarse particles and a step of generating an equilibrium state between a vehicle of coarse particles and a vehicle of fine particles. Regarding the former, it is performed in a relatively short time, but with respect to the latter, reaggregation and redispersion of dispersed particles reach an equilibrium state after taking a certain amount of time. If this process is performed roughly, the dispersion stability is inferior after the preparation of the dispersion, causing re-aggregation and sedimentation of particles, which affects the storage stability and film formability of the dispersion. Therefore, there is an upper limit of the rotor diameter in order to secure a certain amount of dispersion time, rotate the rotor at the minimum number of revolutions, and keep the dispersion stress below a predetermined value. According to experiments by the present inventors, it has been found that the above condition can be satisfied if the diameter of the rotor is 50 mm or less. Moreover, when too small, the capacity | capacitance of a dispersion | distribution chamber will become small, the amount of the dispersion liquid which can be disperse | distributed at a time will become small, and since it will not be suitable for a manufacturing method, what has a diameter of 10 mm or more at least is preferable. Therefore, the range of the diameter of the rotor in this invention is 10 mm or more and 50 mm or less is a suitable range.
[0022]
(3) The dispersion energy affecting the crystal transition is determined by the dispersion stress relative to the weight of the dispersed titanyl phthalocyanine crystal.
[0023]
With respect to the conditions in the method for dispersing titanyl phthalocyanine crystals that have been disclosed so far, for example, as disclosed in Patent Document 4, most of them control the dispersion time. However, as described above, the dispersion stress varies depending on the weight of the titanyl phthalocyanine crystal to be dispersed, the size of the dispersion chamber (rotor), the rotational speed of the rotor, the dispersion time, and the like. For this reason, the optimization of dispersion conditions that has been proposed in the past has not always been sufficient. The present inventors have arranged these relationships and found that the relationship between the trade-off between crystal stability and dispersion stability can be eliminated by controlling the dispersion stress applied per gram of titanyl phthalocyanine crystal. Dispersion stress here is difficult to express as a physically meaningful expression, but according to the study by the present inventors, items that show a strong correlation with dispersion stress (dispersion time, rotor speed, rotor diameter) are used. Thus, it has been found that the following expression is simply used as a substitute definition.
[0024]
[Expression 2]
Dispersion stress (mm) =
Dispersion time (minutes) x number of rotor revolutions per unit time (number of revolutions / minute)
× Rotor diameter (mm) / circumference (π)
The dispersion stress given per gram of titanyl phthalocyanine crystal is obtained by dividing the dispersion stress obtained by the above formula by the weight (g) of the titanyl phthalocyanine crystal to be dispersed.
[0025]
[Equation 3]
Dispersion stress per gram of titanyl phthalocyanine crystal (mm / g)
= Dispersion time (minutes) x number of rotor revolutions per unit time (number of revolutions / minute)
× Rotor diameter (mm) / {weight (g) × circumference (π)}
[0026]
That is, the above problem is
(1) “A method for producing a dispersion containing a titanyl phthalocyanine crystal, using a bead mill type dispersion device, having a dispersion media diameter of 0.5 mm or less, and a rotor installed in the dispersion chamber having a diameter of 50 mm or less And a dispersion stress E given per 1 g of titanyl phthalocyanine crystal subjected to dispersion defined as follows is in the range of 32000 ≦ E ≦ 95000;
[0027]
[Expression 4]
E = T × R × D / (W × π)
Here, T, R, D, W, π, and E are as follows.
T: Dispersion time (minutes)
R: Number of rotor revolutions per unit time (number of revolutions / minute)
D: Rotor diameter (mm)
W: Weight of titanyl phthalocyanine crystal used for dispersion (g)
π: Pi ratio
E: Dispersion stress (g / g) per gram of titanyl phthalocyanine crystal,
(2) “The bead mill type disperser is a circulation type disperser, and the ratio of the volume of the solvent used for dispersion to the capacity of the dispersion chamber is in the range of 10: 1 to 50: 1. The method for producing the dispersion liquid according to (1) above ”,
(3) “The titanyl phthalocyanine crystal has 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 波長) of CuKα. The method for producing a dispersion according to item (1) or (2),
(4) “The titanyl phthalocyanine crystal has a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 （) of CuKα, which is further 9.4 °, 9.6 °, 24. It has a main peak at 0 °, and has a peak at 7.3 ° as a diffraction peak at the lowest angle side, and has no peak in the range of 7.4 to 9.4 °. “Method for producing dispersion according to (3)”,
(5) “The method for producing a dispersion according to (3) or (4) above, wherein the titanyl phthalocyanine further has no peak at 26.3 °”,
(6) As described in any one of (1) to (5) above, the dispersion solvent is at least one selected from ketone solvents, ester solvents, and ether solvents. Manufacturing method of dispersion ",
(7) “The method for producing a dispersion according to any one of (1) to (6) above, wherein a binder resin is used in combination when the titanyl phthalocyanine crystal is dispersed”;
(8) The problem is solved by “the method for producing a dispersion according to any one of (1) to (7) above, wherein water is used in combination when the titanyl phthalocyanine crystal is dispersed”.
[0031]
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 “Phthacocyanine Compounds” (1963), “The Phthalocyanines” (1983), JP-A-6-293769, etc. by Moser et al.
[0032]
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.
[0033]
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 1.514Å) 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 major axis of the primary particles being 0.1 μm or less is important in forming finer primary particles in the subsequent crystal conversion step.
[0034]
Next, a crystal conversion method will be described. Crystal transformation is carried out using at least the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the desired crystal form (characteristic X-ray of CuKα (wavelength 1.542 mm)). And a crystal form having a maximum diffraction peak at 27.2 °. In particular, among the crystal types, there are further major peaks at 9.4 °, 9.6 °, 24.0 °, and the lowest diffraction angle peak at 7.3 °, A titanyl phthalocyanine crystal having no peak in the range of 7.4 to 9.4 ° is preferably used, and a titanyl phthalocyanine crystal having no peak at 26.3 ° is particularly preferably used.
[0035]
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). .
In this case, any organic solvent can be used as long as a desired crystal form can be obtained. In particular, 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.
[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]
Here, the organic pigment having a high photocarrier generation ability used in the present invention generally has a very strong cohesive force. When the crystals are filtered and fractionated and then dried as described above, the primary particles aggregate to form secondary particles. This can be dispersed up to the primary particles by a normal dispersing device, but it may not be dried if the crystal conversion solvent and the dispersion solvent of the dispersion subsequently used are the same. In that case, the wet cake of the titanyl phthalocyanine crystals after filtration may be directly put into a dispersion solvent in which a binder resin is dissolved as necessary to carry out dispersion. This method eliminates the need to disperse large lumps of secondary particles and makes the effects of the present invention even more remarkable.
[0038]
The thus obtained titanyl phthalocyanine crystal is extremely useful as a charge generating material for an electrophotographic photoreceptor. In particular, a crystal type 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 has extremely high photocarrier generation efficiency. It is what has. Among them, the diffraction peak (± 0.2 °) of Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα further has main peaks at 9.4 °, 9.6 °, and 24.0 °. The titanyl phthalocyanine crystal having a peak at 7.3 ° as the diffraction peak on the lowest angle side and not having a peak in the range of 7.4 to 9.4 ° is extremely sensitive and can be used repeatedly. It is a good material with little reduction in chargeability.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Next, a bead mill dispersing apparatus used for preparing the dispersion of the present invention will be described.
The bead mill disperser is generally used for the production of paints and the like. As an example, the bead mill disperser can be exemplified as shown in FIG.
Here, (71) is a motor, (72) is a dispersion chamber, (73) is a pipe, (74) is a circulation tank, (75) is a circulation pump, (77) and (78) are pipes, and (79) is A stand for fixing the dispersion chamber. Although not shown, it is very effective in the present invention to provide a cooling jacket around the dispersion chamber (72) and the circulation tank (74) in FIG. In FIG. 1, a circulation type bead mill dispersing apparatus is described, but a bead mill type other than the circulation type is also applicable to the present invention. However, in consideration of mass production of the dispersion liquid, if it is not a circulation system, a very large dispersion chamber is required or a very large number of dispersion operations must be performed. Therefore, it is extremely effective to adopt a circulation method when producing a dispersion at the manufacturing level.
[0040]
FIG. 2 describes the inside of the dispersion chamber (72) in FIG. In the dispersion chamber, a rotor is attached to a shaft connected to a motor. As shown in FIG. 2, the rotor diameter in the present invention indicates the outer diameter of the rotor. Around the rotor (and inside), the dispersion media is jammed.
As described above, the rotor diameter shown in FIG. 2 is suitably 50 mm or less, and suitably 10 mm or more. In addition, examples of the material constituting the rotor include various metals (for example, stainless steel) and various ceramics (for example, alumina and sirconia). In consideration of wear resistance of repeated use and contamination contamination in the dispersion liquid. Zirconia or partially stabilized zirconia in which a part of the composition is modified with yttrium or the like is preferably used.
[0041]
As for the dispersion medium, the outer diameter is desirably 0.5 mm or less, and preferably 0.1 mm or more. Examples of the material constituting the dispersion medium include materials similar to those of the rotor, but zirconia or partially stabilized zirconia in which a part of the composition is modified with yttrium or the like is preferably used in the dispersion medium.
The rotational speed of the rotor is not particularly limited. However, if the rotational speed is high, the dispersion stress naturally increases, so that excess energy is given to the titanyl phthalocyanine crystal. Therefore, the number of rotations is selected so that the dispersion stress applied per gram of crystal is 32,000 or more and 95,000 or less based on the rotor diameter, dispersion time and the titanyl phthalocyanine crystal weight used. In general, in the case of a rotor with a diameter of 50 mm, a value of about 3000 (rotations / minute) or less is appropriate, and when the rotation speed is too low, the motor rotation speed tends to become unstable, so 500 (rotations / minute) or more is required. preferable.
The dispersion time is inevitably selected from the relationship between the rotor diameter and the weight of the titanyl phthalocyanine crystal used, as well as the rotational speed. When the dispersion time is too short, although the pulverization of the particles proceeds, the dispersion stability may be inferior. The minimum time that an equilibrium state of dispersion and re-aggregation can be created should be ensured. When the rotor diameter is 50 mm and the rotor rotation speed per unit time is 3000 rotations, it is approximately 60 to 360 minutes.
[0042]
Next, a method for producing the dispersion in the present invention will be described.
The pigment used is a titanyl phthalocyanine crystal as described above, preferably at least 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. It is a titanyl phthalocyanine crystal having a crystal form having a maximum diffraction peak. More preferably, it has 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, 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 °. There are no titanyl phthalocyanine crystals. In addition, titanyl phthalocyanine crystals having no peak at 26.3 ° are most suitable. These titanyl phthalocyanine crystals are put together with an organic solvent into the aforementioned bead mill dispersing device and dispersed to prepare a dispersion.
[0043]
The amount of dispersion solvent used, which determines the scale of the entire dispersion. If the circulation method is not adopted, a dispersion solvent having a capacity larger than that of the dispersion chamber cannot be used. For this reason, 1: 1 is appropriate for the volume ratio of the dispersion solvent to the dispersion chamber. On the other hand, when the circulation method is adopted, the ratio can be arbitrarily set by increasing the circulation tank. According to the study by the inventors, if the dispersion stress is proportional to the weight of the titanyl phthalocyanine crystal (in other words, if the dispersion stress per unit weight is constant), the dispersion state (attained particle size, It has been found that the dispersion stability is the same. Therefore, the weight of the titanyl phthalocyanine crystal used and the dispersion time are basically proportional. For this reason, when the scale is increased, the dispersion time should be increased accordingly. However, there arises a problem that the dispersion time becomes too long and the apparatus becomes so large. Furthermore, it is preferable to provide a stirring device in the circulation tank. When the capacity of the circulation tank is increased, the stirring capacity must be increased accordingly, and the energy used (power consumption, etc.) is increased. Resulting in. From the above, the ratio of the amount of use (volume) of the dispersion solvent to the capacity of the dispersion chamber is in a suitable range of about 5: 1 to 50: 1. More preferably, it is in the range of 10: 1 to 50: 1.
[0044]
As a dispersion solvent to be used, a commonly used organic solvent is used as long as it can disperse titanyl phthalocyanine crystals. Examples 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. Among them, good results can be obtained by using one selected from a ketone solvent, an ester solvent, and an ether solvent. These organic solvents may be used alone or in combination.
[0045]
In addition, a binder resin is used in combination when necessary. The combined use of the binder resin is a very effective means because it significantly reduces the crystal transition rate of the titanyl phthalocyanine crystal. Usable binder resins include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, polyacrylamide, and polyvinyl benzal. , Polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like. In particular, polyvinyl butyral can be used most effectively. 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.
[0046]
Further, water is used in combination as needed when dispersing. The combined use of water is a very effective means because the crystal transition rate of the titanyl phthalocyanine crystal is remarkably lowered as in the case of the binder resin. When used, distilled water or ion-exchanged water from which impurities are sufficiently removed is preferably used. If it is used in a large amount, problems such as dispersibility decrease, separation from an organic solvent, and precipitation of a binder resin occur. For this reason, depending on the type of organic solvent used, in the case of a hydrophobic solvent, the upper limit of the water solubility of the organic solvent, and in the case of a hydrophilic solvent, 2 to 3 wt% with respect to the weight of the organic solvent The degree is the upper limit.
As described above, a dispersion containing a titanyl phthalocyanine crystal is produced.
[0047]
Next, the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
FIG. 3 is a cross-sectional view showing the electrophotographic photosensitive member of the present invention. On the conductive support (31), a charge generation layer (35) containing a charge generation material as a main component and a charge transport material as a main component. Charge transport layer (37).
FIG. 4 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member of the present invention, in which a protective layer (39) is laminated on the charge generation layer (35) and the charge transport layer (37). Have taken.
[0048]
The conductive support (31) 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. In addition, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as the conductive support (31).
[0049]
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).
[0050]
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 performed in the range of electrolytic voltage: 5-30 V, treatment time: about 5-60 minutes, but is not limited thereto. Since the anodic oxide film produced in this way 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.
[0051]
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.
[0052]
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 (deionized) as possible. 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 desirably about 5-15 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.
[0053]
In addition to the above, a conductive powder dispersed in a suitable binder resin and coated on the support can be used as the conductive support (31) of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, 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.
[0054]
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 (31) of the present invention.
[0055]
Next, the photosensitive layer will be described.
The charge generation layer (35) is a layer formed using the dispersion liquid mainly composed of the titanyl phthalocyanine crystal described above. Preferably, it is a step of converting into a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα into a crystal form having a maximum diffraction peak at 27.2 °. . In particular, among the crystal types, there are further major peaks at 9.4 °, 9.6 °, 24.0 °, and the lowest diffraction angle peak at 7.3 °, A titanyl phthalocyanine crystal having no peak in the range of 7.4 to 9.4 ° is preferably used, and a titanyl phthalocyanine crystal having no peak at 26.3 ° is particularly preferably used. As the coating method of the dispersion, methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, and the like can be used. The film thickness of the charge generation layer (35) is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.
[0056]
The charge transport layer (37) 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.
[0057]
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.
[0058]
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.
[0059]
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. Of these, non-halogen solvents such as cyclic ethers such as tetrohydrofuran and dioxane, and aromatic hydrocarbons such as toluene and xylene are preferably used.
When these non-halogen solvents are used as the coating solvent for the charge transport layer and titanyl phthalocyanine crystals are used as the charge generation material, there may be cases where the desired photosensitivity cannot be obtained. Such a case does not occur when formed. The reason for this is presumed to be that micronization is progressing and crystal transition is small.
[0060]
In addition, a polymer charge transport material having a function as a charge transport material and a function of a binder resin is also preferably used for the charge transport layer. 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.
[0061]
[Chemical 1]

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.
[0062]
[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
[0063]
[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 Each may be the same or different)
[0064]
[Formula 4]

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).
[0065]
[Chemical formula 5]

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).
[0066]
[Chemical 6]

Where R ₁₁ , R ₁₂ Is a substituted or unsubstituted aryl group, Ar ₇ , Ar ₈ , Ar ₉ Are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are the same as in the case of formula (I).
[0067]
[Chemical 7]

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).
[0068]
[Chemical 8]

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).
[0069]
[Chemical 9]

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).
[0070]
[Chemical Formula 10]

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).
[0071]
Embedded image

Where R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ Is a substituted or unsubstituted aryl group, Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ , Ar ₂₈ Represent the same or different arylene groups. X, k, j and n are the same as in the case of formula (I).
[0072]
Embedded image

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).
[0073]
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.
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.
[0074]
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.
[0075]
In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer (37). As the plasticizer, those used as 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.
[0076]
As the binder resin, the binder resin previously mentioned in the charge transport layer (37) may be used as it is, or the binder resin mentioned in the method for preparing the dispersion 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.
[0077]
In the electrophotographic photosensitive member of the present invention, an undercoat layer can be provided between the conductive support (31) 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.
[0078]
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.
[0079]
In the electrophotographic photoreceptor of the present invention, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. Materials used for the protective layer include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, Polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, poly Examples of the resin include vinylidene chloride and epoxy resin. In addition to the protective layer, fluorine resins such as polytetrafluoroethylene, silicone resins, and those resins in which inorganic materials such as titanium oxide, tin oxide, and potassium titanate are dispersed are used for the purpose of improving wear resistance. Can be added. 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.
[0080]
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.
[0081]
Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 5 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. 5, the photoreceptor (41) is provided with a charge generation layer containing a titanyl phthalocyanine crystal dispersed under a specific dispersion condition and a charge transport layer on a conductive support. The charging member (43), the pre-transfer charger (46), the transfer charger (49), the separation charger (50), and the pre-cleaning charger (52) include corotron, scorotron, solid state charger, and charging. Known means such as a roller are used. As the charging member, one that is in contact with or close to the photoreceptor (41) 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.
[0082]
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 photosensitive member and the surface of the charging member. It is distinguished from known chargers typified by corotron and scorotron from the distance of the gap. 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.
[0083]
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.
[0084]
As the transfer means, the above charger can be generally used. However, as shown in FIG. 5, a combination of the transfer charger (49) and the separation charger (50) is effective.
An LD or LED is used as the light source of the image exposure unit (44). 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 (42). 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 process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG.
[0085]
The toner developed on the photoconductor (41) by the developing unit (45) is transferred to the transfer paper (48), but not all is transferred but remains on the photoconductor (41). Toner is also produced. Such toner is removed from the photoreceptor by the fur brush (53) and the blade (54). 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.
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.
[0086]
FIG. 7 shows another example of the electrophotographic process according to the present invention. The photoreceptor (21) is formed by providing a charge generation layer and a charge transport layer containing titanyl phthalocyanine crystals dispersed under a specific dispersion condition on a conductive support. Driven by driving rollers (22a, 22b), charged by a charger (23), image exposure by a light source (24), development (not shown), transfer using a charger (25), before cleaning by a light source (26) Exposure, cleaning with the brush (27), and static elimination with the light source (28) are repeated. In FIG. 7, light exposure for image exposure is performed on the photoconductor (21) (of course, the support is translucent) from the support side. The image exposure source (24) is preferably an LD or an LED.
[0087]
The above illustrated electrophotographic process exemplifies an embodiment of the present invention, and of course, other embodiments are possible. For example, in FIG. 5, 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, in the light irradiation process, image exposure, pre-cleaning exposure, and static elimination exposure are illustrated. In addition, pre-exposure exposure, pre-exposure of image exposure, and other known light irradiation processes are provided to light the photosensitive member. Irradiation can also be performed.
[0088]
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 photoconductor (16) is provided with a charge generation layer containing a titanyl phthalocyanine crystal dispersed under a specific dispersion condition on a conductive support and a charge transport layer.
[0089]
FIG. 9 is a schematic diagram for explaining the tandem-type full-color electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 9, (1C, 1M, 1Y, 1K) is a drum-shaped photoconductor, and this photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow in the figure, and around it at least in the order of rotation. A charging member (2C, 2M, 2Y, 2K), a developing member (4C, 4M, 4Y, 4K), and a cleaning member (5C, 5M, 5Y, 5K) are arranged. The charging members (2C, 2M, 2Y, 2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor. Laser light (3C, 3M, 3Y, 3K) from an exposure member (not shown) from the back side of the photoreceptor between the charging member (2C, 2M, 2Y, 2K) and the developing member (4C, 4M, 4Y, 4K) , And an electrostatic latent image is formed on the photoreceptor (1C, 1M, 1Y, 1K). Then, four image forming elements (6C, 6M, 6Y, 6K) centering on such a photoreceptor (1C, 1M, 1Y, 1K) are along a transfer conveyance belt (10) which is a transfer material conveyance means. Are juxtaposed. The transfer / conveying belt (10) is provided between the developing member (4C, 4M, 4Y, 4K) and the cleaning member (5C, 5M, 5Y, 5K) of each image forming unit (6C, 6M, 6Y, 6K). 1C, 1M, 1Y, 1K), and a transfer brush (11C, 11M, 11Y, 11K) for applying a transfer bias to the back surface (back surface) of the transfer conveyance belt (10) that contacts the back side of the photoconductor. Is arranged. Each of the image forming elements (6C, 6M, 6Y, 6K) has a different toner color inside the developing device, and all other components have the same configuration.
[0090]
In the color electrophotographic apparatus having the configuration shown in FIG. 9, the image forming operation is performed as follows. First, in each image forming element (6C, 6M, 6Y, 6K), the charging member (2C, 2M, 2Y) in which the photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow (direction along with the photoconductor). , 2K), and then an electrostatic latent image corresponding to each color image to be created by laser light (3C, 3M, 3Y, 3K) by an exposure unit (not shown) disposed inside the photoconductor. It is formed. Next, the latent image is developed by the developing members (4C, 4M, 4Y, 4K) to form a toner image. The developing members (4C, 4M, 4Y, 4K) are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. 1M, 1Y, 1K) toner images of the respective colors 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 / conveying belt (10) is conveyed, and the toner images of the respective colors are transferred at the contact positions (transfer portions) with the photoconductors (1C, 1M, 1Y, 1K). It is. The toner image on the photosensitive member is transferred onto the transfer paper (by the electric field formed by the potential difference between the transfer bias applied to the transfer brush (11C, 11M, 11Y, 11K) and the photosensitive member (1C, 1M, 1Y, 1K). 7) Transferred on top. 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, the residual toner remaining on the respective photoconductors (1C, 1M, 1Y, 1K) without being transferred by the transfer unit is collected by the cleaning device (5C, 5M, 5Y, 5K). In the example of FIG. 9, 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 for stopping the image forming elements (6C, 6M, 6Y) other than black. Further, although the charging member is in contact with the photosensitive member in FIG. 9, 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 reduced. Less toner filming and good use.
[0091]
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.
[0092]
【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.
[0093]
(Pigment production 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 at room temperature. When the dark blue color of the paste changed to light blue, the stirring was stopped and immediately filtered under reduced pressure. 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. After drying, titanyl phthalocyanine crystals were ground using a commercially available mixer to make a fine powder of about 150 μm. This is designated as Pigment 1.
[0094]
Part of the water paste obtained in Pigment Preparation 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 crystal (pigment 1) obtained in Pigment Preparation Example 1 were measured under the following conditions.
X-ray tube Cu
Voltage 40kV
Current 20mA
Scanning speed 1 ° / min
Scanning range 3 ° ~ 40 °
Time constant 2 seconds
[0095]
The X-ray diffraction spectrum of the dry powder of water paste is shown in FIG. 10, and the X-ray diffraction spectrum of Pigment 1 is shown in FIG.
From FIG. 11, Pigment 1 has a maximum diffraction peak at 27.2 °, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, and the diffraction at the lowest angle side. The titanyl phthalocyanine crystal has a crystal form having a peak at 7.3 °, no peak in the range of 7.4 to 9.4 °, and no peak at 26.3 °. I understand.
[0096]
Example 1
A dispersion having the following composition was prepared by bead milling under the conditions shown below (this is referred to as Dispersion 1).
240 parts of titanyl phthalocyanine crystal prepared in Pigment Preparation Example 1
(Pigment 1)
160 parts of polyvinyl butyral
(Sekisui Chemical: BX-1)
2-butanone 3600 parts
[0097]
Using commercially available bead mill disperser (VMA-GETZMANN GMBH: DISPERMAT SL, rotor diameter is 50 mm, dispersion chamber capacity is 125 ml), zirconia balls with a diameter of 0.5 mm are used, and all of 2-butanone and pigment in which polyvinyl butyral is dissolved Then, dispersion was performed for 300 minutes at a rotor rotational speed of 3000 (rotation / minute) (dispersion stress per gram of titanyl phthalocyanine crystal is 59713).
After completion of the dispersion, the mill base was discharged from the bead mill disperser, and further 10300 g of 2-butanone was added, and all the mill base remaining in the disperser was discharged simultaneously with the dilution to prepare a dispersion.
[0098]
(Example 2)
A dispersion was prepared in the same manner as in Example 1 except that the rotor rotation speed was changed to 1000 (rotation / minute) and the dispersion time was 500 minutes among the dispersion preparation conditions of Example 1 (Titanyl phthalocyanine). The dispersion stress per gram of crystal is 33174). This is Dispersion Liquid 2.
[0099]
(Example 3)
A dispersion was prepared in the same manner as in Example 1 except that the rotor rotation speed was changed to 5000 (rotation / minute) and the dispersion time was 200 minutes among the dispersion preparation conditions of Example 1 (titanyl phthalocyanine). The dispersion stress per gram of crystal is 66348). This is Dispersion Liquid 3.
[0100]
(Comparative Example 1)
A dispersion was prepared in the same manner as in Example 1 except that the rotor rotation speed was changed to 1000 (rotations / minute) among the dispersion preparation conditions of Example 1 (dispersion stress per 1 g of titanyl phthalocyanine crystal was 19004. Is). This is Dispersion Liquid 4.
[0101]
(Comparative Example 2)
A dispersion was prepared in the same manner as in Example 1 except that the rotor rotational speed was changed to 5000 (rotations / minute) among the dispersion preparation conditions of Example 1 (dispersion stress per gram of titanyl phthalocyanine crystal was 99522. Is). This is designated as Dispersion Liquid 5.
[0102]
(Comparative Example 3)
A dispersion was prepared in the same manner as in Example 1 except that the dispersion time was changed to 150 minutes in the dispersion preparation conditions of Example 1 (dispersion stress per 1 g of titanyl phthalocyanine crystal was 29857). This is designated as Dispersion Liquid 6.
[0103]
Example 4
A dispersion having the following composition was prepared by bead milling under the conditions shown below (this is referred to as Dispersion 7).
360 parts of titanyl phthalocyanine crystal prepared in Pigment Preparation Example 1
(Pigment 1)
240 parts of polyvinyl butyral
(Sekisui Chemical: BX-1)
2-butanone 5400 parts
[0104]
Using commercially available bead mill disperser (VMA-GETZMANN GMBH: DISPERMAT SL, rotor diameter is 50 mm, dispersion chamber capacity is 125 ml), zirconia balls with a diameter of 0.5 mm are used, and all of 2-butanone and pigment in which polyvinyl butyral is dissolved Then, dispersion was performed for 750 minutes at a rotor rotation speed of 1000 (rotation / minute) (dispersion stress per gram of titanyl phthalocyanine crystal is 33174).
After completion of the dispersion, the mill base was discharged from the bead mill disperser, and further 15450 g of 2-butanone was added, and all the mill base remaining in the disperser was discharged simultaneously with the dilution to prepare a dispersion.
[0105]
(Example 5)
A dispersion having the following composition was prepared by bead milling under the conditions shown below (this is referred to as Dispersion 8).
48 parts of titanyl phthalocyanine crystal prepared in Pigment Preparation Example 1
(Pigment 1)
Polyvinyl butyral 32 parts
(Sekisui Chemical: BX-1)
720 parts of 2-butanone
[0106]
Using commercially available bead mill disperser (VMA-GETZMANN GMBH: DISPERMAT SL, rotor diameter is 50 mm, dispersion chamber capacity is 125 ml), zirconia balls with a diameter of 0.5 mm are used, and all of 2-butanone and pigment in which polyvinyl butyral is dissolved The dispersion was carried out for 60 minutes at a rotor rotational speed of 3000 (rotations / minute) (dispersion stress per gram of titanyl phthalocyanine crystal is 59713).
After the dispersion was completed, the mill base was discharged from the bead mill disperser, and further 2060 g of 2-butanone was added. All the mill base remaining in the disperser was discharged at the same time as the dilution to prepare a dispersion.
[0107]
(Comparative Example 4)
A dispersion was prepared in the same manner as in Example 4 except that the dispersion time in the dispersion preparation conditions of Example 5 was changed to 30 minutes (dispersion stress per 1 g of titanyl phthalocyanine crystal was 29857). This is designated as Dispersion Liquid 9.
[0108]
(Comparative Example 5)
A dispersion was prepared in the same manner as in Example 4 except that the dispersion time was changed to 120 minutes in the dispersion preparation conditions of Example 5 (dispersion stress per gram of titanyl phthalocyanine crystal was 119427). This is designated as Dispersion Liquid 10.
[0109]
(Example 6)
A dispersion having the following composition was prepared by bead milling under the conditions shown below (this is referred to as Dispersion 11).
120 parts of titanyl phthalocyanine crystal prepared in Pigment Preparation Example 1
(Pigment 1)
80 parts of polyvinyl butyral
(Sekisui Chemical: BX-1)
2-butanone 1800 parts
[0110]
Using commercially available bead mill disperser (VMA-GETZMANN GMBH: DISPERMAT SL, rotor diameter is 50 mm, dispersion chamber capacity is 125 ml), zirconia balls with a diameter of 0.5 mm are used, and all of 2-butanone and pigment in which polyvinyl butyral is dissolved The dispersion was carried out for 150 minutes at a rotor rotational speed of 3000 (rotations / minute) (dispersion stress per gram of titanyl phthalocyanine crystal is 59713).
After the dispersion was completed, the mill base was discharged from the bead mill disperser, and 5150 g of 2-butanone was further charged. All the mill base remaining in the disperser was discharged simultaneously with the dilution to prepare a dispersion.
[0111]
(Example 7)
A dispersion was prepared in the same manner as in Example 1 except that the zirconia balls used were changed to those having a diameter of 0.3 mm under the dispersion preparation conditions of Example 1 (this is referred to as Dispersion 12).
[0112]
(Comparative Example 6)
A dispersion was prepared in the same manner as in Example 1 except that the zirconia balls used were changed to those having a diameter of 0.8 mm under the dispersion preparation conditions of Example 1 (this is referred to as Dispersion 13).
[0113]
(Comparative Example 7)
The dispersion chamber of the dispersion apparatus used in Example 1 was changed to one having a capacity of 500 ml (rotor diameter: 75 mm), and a dispersion was prepared in the same manner as the other dispersion conditions (this is referred to as dispersion 14).
[0114]
(Comparative Example 8)
A dispersion was prepared in the same manner as in Example 2 except that the dispersion chamber of the dispersion apparatus used in Example 2 was changed to one having a capacity of 500 ml (rotor diameter was 75 mm) and the dispersion time was changed to 333 minutes (this) To dispersion 15).
[0115]
Dispersions 1 to 15 produced as described above were evaluated as follows. The results are shown in Table 1.
Average particle diameter HORIBA, Ltd .: Volume average particle diameter was evaluated by CAPA700.
Observation of coarse particles The dispersion was applied to a slide glass to prepare a sample for observation.
Subsequently, the coating film was observed with a commercially available optical microscope (50 to 100 times).
X-ray diffraction spectrum The dispersion was dried and powdered, and the X-ray diffraction spectrum was measured in the same manner as described above.
Evaluation of film formability Films were formed on a washed aluminum plate by dip coating, and the state of the coating film was observed.
[0116]
[Table 1]

[0117]
As can be seen from Table 1, by setting the dispersion stress per 1 g of pigment (titanyl phthalocyanine crystal) within an appropriate range (32000-95000), the dispersion stability is high (the average particle size is fine and even when observed at the microscopic level). A dispersion is formed in a state where coarse particles are not recognized) and the crystal stability is high (maintaining the same crystal form as before dispersion). By using such a dispersion, a good coating film is formed.
It can also be seen that the average particle size does not change greatly even under various conditions, and that the dispersion stability of the dispersion cannot be expressed only by the average particle size evaluated so far.
In addition, even when the amount of dispersion energy is appropriate, when the media diameter is larger than 0.5 mm, the dispersion stability is inferior, and coarse particles observed at the microscopic level remain, and when this is used to form a film It has an adverse effect.
Further, when the rotor diameter is large, dispersion tends to become unstable, and even when the dispersion stress is appropriate, crystal transition or coarse particles are observed. This indicates that it is difficult to achieve both crystal stability and dispersion stability.
[0118]
Regarding the relationship between the amount of the dispersion solvent and the dispersion chamber volume, when it is larger than 50: 1, a suitable dispersion can be produced by applying an appropriate dispersion stress, but the dispersion time becomes extremely long. End up. On the other hand, when the ratio is smaller than 10: 1, in order to set an appropriate amount of dispersion energy, the dispersion time may be too short and the dispersion stability may be slightly inferior.
[0119]
FIG. 12 shows an X-ray diffraction spectrum when a part of the crystal has undergone crystal transition (Comparative Example 2). The arrow in the figure is a new peak (26.3 °) that is not observed in the crystal of FIG.
[0120]
Embedded image

[0121]
(Example 8)
A dispersion was prepared in the same manner as in Example 1 except that the solvent used in the dispersion of Example 1 was changed from 2-butanone to n-butyl acetate (this is referred to as Dispersion 16).
[0122]
Example 9
A dispersion was prepared in the same manner as in Example 1 except that the solvent used in the dispersion of Example 1 was changed from 2-butanone to n-butanol (this is referred to as Dispersion 17).
[0123]
(Example 10)
A dispersion was prepared in the same manner as in Example 1 except that the composition of the dispersion of Example 1 was changed to the following composition (this is referred to as Dispersion 18).
240 parts of titanyl phthalocyanine crystal prepared in Pigment Preparation Example 1
(Pigment 1)
160 parts of polyvinyl butyral
(Sekisui Chemical: BX-1)
Tetrahydrofuran 3600 parts
36 parts of ion exchange water
[0124]
(Example 11)
A dispersion was prepared in the same manner as in Example 10 except that ion-exchanged water was removed from the dispersion of Example 10 (this is referred to as Dispersion 19).
[0125]
(Example 12)
A dispersion was prepared in the same manner as in Example 1 except that polyvinyl butyral was removed from the dispersion of Example 1 (this is referred to as Dispersion 20).
The dispersions 16 to 20 produced as described above were evaluated in the same manner as the dispersions 1 to 15. The results are shown in Table 2 together with the results of Example 1.
[0126]
[Table 2]

As can be seen from Table 2, when 2-butanone (ketone solvent), n-butyl acetate (ester solvent), or tetrahydrofuran (ether solvent) is used as the dispersion solvent, a dispersion having good characteristics is obtained. However, when n-butanol (alcohol solvent), which is another solvent, was used, the dispersion stability was slightly inferior.
Moreover, when ion-exchange water was not added or when binder resin was not added, the case where it was inferior to crystal stability was recognized.
[0127]
(Pigment production example 2)
A pigment was prepared according to the method described in JP-A-1-299874 (Patent No. 2512081) and Example 1. That is, the wet cake prepared in the previous pigment preparation example 1 was dried, 200 g of the dried product was added to 1000 g of polyethylene glycol, and sand milling was performed together with 20000 g of glass beads. After the crystal transition, the mixture was washed successively with dilute sulfuric acid and an aqueous ammonium hydroxide solution and dried to obtain a pigment (this is referred to as Pigment 2).
[0128]
(Pigment production example 3)
A pigment was produced according to the method described in JP-A-3-269064 (Japanese Patent No. 2854682) and Production Example 1. That is, the wet cake prepared in the above pigment preparation example 1 was dried, 200 g of the dried product was stirred in a mixed solvent of 2000 g of ion-exchanged water and 200 g of monochlorobenzene for 1 hour (50 ° C.), and then methanol and ion-exchanged water. It was washed and dried to obtain a pigment (this is referred to as Pigment 3).
[0129]
(Pigment production example 4)
A pigment was produced according to the method described in the production example of JP-A-2-8256 (Japanese Patent Publication No. 7-91486). That is, 196 g of phthalodinitrile and 1500 ml of 1-chloronaphthalene are stirred and mixed, and 44 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 referred to as Pigment 4).
[0130]
(Pigment preparation example 5)
A pigment was prepared according to the method described in JP-A No. 64-17066 (Japanese Patent Publication No. 7-97221) and Synthesis Example 1. That is, 200 parts of α-type TiOPc was subjected to crystal conversion treatment at 100 ° C. for 10 hours with a sand grinder together with 400 g of sodium chloride and 200 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 then dried to obtain a pigment (this is referred to as Pigment 5).
[0131]
(Pigment preparation example 6)
A pigment was prepared according to the method described in JP-A No. 11-5919 (Japanese Patent No. 3003664) and Example 1. That is, 204 parts of O-phthalodinitrile and 76 parts of titanium tetrachloride were heated and reacted in 500 parts of quinoline at 200 ° C. for 2 hours, the solvent was removed by steam distillation, 2% aqueous chloride solution, followed by 2% hydroxylation. The resulting solution was purified with an aqueous sodium solution, washed with methanol and N, N-dimethylformamide, and then dried to obtain titanyl phthalocyanine. 200 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 8000 parts of ice water stirred at 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 was stirred in 10000 parts of THF for about 5 hours, filtered, washed with THF and dried to obtain a pigment (this is referred to as Pigment 6).
[0132]
(Pigment preparation example 7)
A pigment was prepared according to the method described in JP-A-3-255456 (Patent No. 3005052) and Synthesis Example 2. That is, 400 parts of the wet cake prepared in Pigment Preparation Example 1 was mixed with 600 parts of sodium chloride and 280 parts of diethylene glycol, and milled for 60 hours with an automatic mortar under heating at 80 ° C. Next, sufficient washing was performed to completely remove sodium chloride and diethylene glycol contained in the treated product. After drying this under reduced pressure, 8000 parts of cyclohexanone and glass beads having a diameter of 1 mm were added, and the mixture was treated with a sand mill for 30 minutes to obtain a pigment (hereinafter referred to as pigment 7).
[0133]
The pigments prepared in the above pigment preparation examples 2 to 7 were measured for X-ray diffraction spectra by the same method as described above, and confirmed to be the same as the spectra described in the respective publications. Table 3 shows the characteristics of each X-ray diffraction spectrum and the peak position of the X-ray diffraction spectrum of the pigment obtained in Pigment Preparation Example 1.
[0134]
[Table 3]

[0135]
(Example 13)
A dispersion was prepared in the same manner as in Example 6 except that pigment 2 was used instead of the titanyl phthalocyanine crystal (pigment 1) used in Example 6 (this is referred to as dispersion 21).
[0136]
(Example 14)
A dispersion was prepared in the same manner as in Example 6 except that pigment 3 was used in place of the titanyl phthalocyanine crystal (pigment 1) used in Example 6 (referred to as dispersion 22).
[0137]
(Example 15)
A dispersion was prepared in the same manner as in Example 6 except that pigment 4 was used in place of the titanyl phthalocyanine crystal (pigment 1) used in Example 6 (these are referred to as dispersion 23).
[0138]
(Example 16)
A dispersion was prepared in the same manner as in Example 6 except that pigment 5 was used in place of the titanyl phthalocyanine crystal (pigment 1) used in Example 6 (these are referred to as dispersion 24).
[0139]
(Example 17)
A dispersion was prepared in the same manner as in Example 6 except that pigment 6 was used in place of the titanyl phthalocyanine crystal (pigment 1) used in Example 6 (these are referred to as dispersion 25).
[0140]
(Example 18)
A dispersion was prepared in the same manner as in Example 6 except that pigment 7 was used in place of the titanyl phthalocyanine crystal (pigment 1) used in Example 6 (this is referred to as dispersion 26).
[0141]
The dispersions 21 to 26 produced as described above were evaluated in the same manner as in Example 6, and are shown in Table 4 together with the results of Example 6.
[0142]
[Table 4]

As can be seen from Table 4, even when a titanyl phthalocyanine crystal having a different crystal form from that of pigment 1 is used, dispersion is performed by applying an appropriate dispersion stress, so that no crystal transition occurs and no dispersion is caused. A highly dispersible dispersion could be produced.
[0143]
<Production of photoconductor>
(Photosensitive member production example 1)
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 19 μm charge transport layer were formed to produce a laminated photoreceptor (this is referred to as “photoreceptor 1”).
[0144]
◎ 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%), Dai Nippon Ink
Made by Gaku Kogyo)
Melamine resin 10 parts
(Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals)
2-butanone 100 parts
[0145]
◎ Charge generation layer coating solution
The dispersion 1 described above was used.
[0146]
◎ Charge transport layer coating solution
10 parts of polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
7 parts of charge transport material with the following structural formula
[0147]
Embedded image

80 parts of tetrahydrofuran
[0148]
(Photosensitive member preparation example 2)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 2 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 2). ).
[0149]
(Photoreceptor Preparation Example 3)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 3 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 3). ).
[0150]
(Photosensitive member production example 4)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 4 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 4). ).
[0151]
(Photoreceptor Preparation Example 5)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion Liquid 5 was used instead of Dispersion Liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 5). ).
[0152]
(Photosensitive member preparation example 6)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 6 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 6). ).
[0153]
(Photoreceptor Preparation Example 7)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 7 was used in place of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 7). ).
[0154]
(Photoreceptor Preparation Example 8)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 8 was used in place of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 8). ).
[0155]
(Photoreceptor Preparation Example 9)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 9 was used in place of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 9). ).
[0156]
(Photoreceptor Preparation Example 10)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 10 was used in place of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 10). ).
[0157]
(Photoreceptor Preparation Example 11)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 11 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 11). ).
[0158]
(Photoconductor Preparation Example 12)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 12 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this photoconductor is referred to as Photoconductor 12). ).
[0159]
(Photoreceptor Preparation Example 13)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 13 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 13). ).
[0160]
(Photoreceptor Preparation Example 14)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 14 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this photoconductor is referred to as Photoconductor 14). ).
[0161]
(Photoreceptor Preparation Example 15)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 15 was used in place of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 15). ).
[0162]
(Photoreceptor Production Example 16)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the dispersion liquid 16 was used instead of the dispersion liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is referred to as Photoconductor 16). ).
[0163]
(Photoreceptor Preparation Example 17)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 17 was used in place of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 17). ).
[0164]
(Photoreceptor Preparation Example 18)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the dispersion liquid 18 was used in place of the dispersion liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is referred to as Photoconductor 18). ).
[0165]
(Photoreceptor Preparation Example 19)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the dispersion liquid 19 was used instead of the dispersion liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is referred to as Photoconductor 19). ).
[0166]
(Photoreceptor Preparation Example 20)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 20 was used in place of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is Photoconductor 20). ).
[0167]
(Photoconductor Preparation Example 21)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion 21 was used instead of Dispersion 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this photoconductor is referred to as Photoconductor 21). ).
[0168]
(Photoconductor Preparation Example 22)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion Liquid 22 was used instead of Dispersion Liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is referred to as Photoconductor 22). ).
[0169]
(Photoconductor Preparation Example 23)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion Liquid 23 was used instead of Dispersion Liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is referred to as Photoconductor 23). ).
[0170]
(Photoconductor Preparation Example 24)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the dispersion liquid 24 was used in place of the dispersion liquid 1 as the charge generation layer coating solution in the photoconductor preparation 1 (this is referred to as the photoconductor 24). .
[0171]
(Photoconductor Preparation Example 25)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that Dispersion Liquid 25 was used instead of Dispersion Liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is referred to as Photoconductor 25). ).
[0172]
(Photoconductor Preparation Example 26)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the dispersion liquid 26 was used in place of the dispersion liquid 1 as the charge generation layer coating solution in Photoconductor Preparation Example 1 (this is referred to as Photoconductor 26). ).
[0173]
(Examples 19 to 36 and Comparative Examples 9 to 16)
The photoreceptors 1 to 26 produced as described above were mounted on a commercially available plain paper copying machine (manufactured by Ricoh: imagioMF4550). As an AC power source, another power source was prepared outside the copying machine.
The image exposure light source was a 780 nm semiconductor laser (image writing by a polygon mirror).
As the charging member, a charging roller of a non-contact proximity arrangement system as shown in FIG. An image was output under the following charging conditions.
<Charging conditions>
DC bias: -900V
AC bias: 2.3 kV (peak to peak), frequency 2 kHz
Using a chart with a writing rate of 6%, 5000 sheets were continuously printed, and images at the initial stage and after 5000 sheets were evaluated. In the image evaluation, a white solid image was output at the initial stage and after 5000 sheets, and the background stain was evaluated (evaluated by the following rank). Further, halftone images including black circles (black solid) having a diameter of 1 cm at the four corners and the center were output at the initial stage and after 5000 sheets for image evaluation. The results are shown in Table 5.
[0174]
[Table 5]

<Soil dirt rank>
5: Almost no soiling,
4: Slightly,
3: Actual use limit level,
2 or less: Level that cannot withstand actual use
[0175]
(Photoconductor Preparation Example 27)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge transport layer coating solution in Photoconductor Preparation Example 1 was changed to one having the following composition (this is referred to as Photoconductor 27).
[0176]
◎ Charge transport layer coating solution
10 parts of polymer charge transport material with the following composition
(Weight average molecular weight: about 140,000)
[0177]
Embedded image

0.5 parts of additive with the following structure
[0178]
Embedded image

Tetrahydrofuran 100 parts
[0179]
(Photoreceptor Preparation Example 28)
Same as Photoconductor Preparation Example 1 except that the thickness of the charge transport layer in Photoconductor Preparation Example 1 was 17 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 2 μm protective layer was provided. A photoconductor was prepared (this is referred to as photoconductor 28).
[0180]
◎ Protective layer coating solution
10 parts of polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
7 parts of charge transport material with the following structural formula
[0181]
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
[0182]
(Photoconductor Preparation Example 29)
Same as Photoconductor Preparation Example 1 except that the thickness of the charge transport layer in Photoconductor Preparation Example 1 was 17 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 2 μm protective layer was provided. A photoconductor was prepared (hereinafter referred to as photoconductor 29).
[0183]
◎ Protective layer coating solution
17 parts of polymer charge transport material of the following structural formula
(Weight average molecular weight: about 140,000)
[0184]
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
[0185]
(Photoreceptor Preparation Example 30)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge transport layer coating solution in Photoconductor Preparation Example 1 was changed to one having the following composition (this is referred to as Photoconductor 30).
[0186]
◎ Charge transport layer coating solution
10 parts of polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
7 parts of charge transport material with the following structural formula
[0187]
Embedded image

80 parts of toluene
[0188]
(Photoreceptor Preparation Example 31)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge transport layer coating solution in Photoconductor Preparation Example 1 was changed to one having the following composition (this is referred to as Photoconductor 31).
[0189]
◎ Charge transport layer coating solution
10 parts of polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
7 parts of charge transport material with the following structural formula
[0190]
Embedded image

80 parts of methylene chloride
[0191]
(Photoconductor Preparation Example 32)
The aluminum cylinder (JIS 1050) in photoreceptor preparation example 1 is subjected to the following anodic oxide film treatment, and then a charge generation layer and a charge transport layer are provided in the same manner as in photoreceptor preparation example 1 without providing an undercoat layer. (This is referred to as a photoreceptor 32).
[0192]
◎ 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, the substrate was washed with pure water to obtain a support on which a 7 μm anodic oxide film was formed.
[0193]
The photoconductors 1 and 27 to 32 produced as described above were mounted on a commercially available plain paper copying machine (manufactured by Ricoh: imagioMF4550). As an AC power source, another power source was prepared outside the copying machine.
The image exposure light source was a 780 nm semiconductor laser (image writing by a polygon mirror).
As the charging member, a charging roller of a non-contact proximity arrangement system as shown in FIG. An image was output under the following charging conditions.
<Charging conditions>
DC bias: -900V
AC bias: 2.3 kV (peak to peak), frequency 2 kHz
[0194]
Using a chart with a writing rate of 6%, 10,000 sheets were continuously printed, 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 to evaluate the background stain (evaluated by the following rank). In addition, a halftone image including black circles (solid black) having a diameter of 1 cm at the four corners and the center was output at the initial stage and after 10,000 sheets for image evaluation.
The results are shown in Table 6.
[0195]
[Table 6]

<Soil dirt rank>
5: Almost no soiling,
4: Slightly,
3: Actual use limit level,
2 or less: Level that cannot withstand actual use
[0196]
(Example 44)
In the evaluation of Example 37, the evaluation was performed in the same manner as in Example 37 except that the charging conditions were changed to the following conditions. The results are shown in Table 7.
<Charging conditions>
DC bias: -1700V
(Set so that the potential of the unexposed portion on the surface of the photosensitive member becomes −900 V)
[0197]
(Example 45)
In the evaluation of Example 44, the charging roller to be used was changed to a contact method (the roller material is the same and the insulating tape at both ends is not wound), and an image was output under the following charging conditions. The results are shown in Table 7.
<Charging conditions>
DC bias: -1650V
(Set so that the potential of the unexposed portion on the surface of the photosensitive member becomes −900 V)
[0198]
(Example 46)
In the evaluation of Example 44, the charging roller to be used was changed to a contact method (the roller material is the same and the insulating tape at both ends is not wound), and an image was output under the following charging conditions. The results are shown in Table 7.
<Charging conditions>
DC bias: -900V
AC bias: 2.3 kV (peak to peak), frequency 2 kHz
[0199]
(Example 47)
In the evaluation of Example 37, the evaluation was performed in the same manner as in Example 37 except that the thickness of the insulating tape was changed and the gap was changed to 150 μm. The results are shown in Table 7.
[0200]
(Example 48)
In the evaluation of Example 37, the evaluation was performed in the same manner as in Example 37 except that the thickness of the insulating tape was changed and the gap was changed to 250 μm. The results are shown in Table 7.
[0201]
(Example 49)
In the evaluation of Example 37, the scorotron charger was used as the charging member to be used. At this time, the copying machine used for the test was modified so that the scorotron charger could be installed. The charging conditions are as follows.
DC bias: -6.5 kV
[0202]
[Table 7]

<Soil dirt rank>
5: Almost no soiling,
4: Slightly,
3: Actual use limit level,
2 or less: Level that cannot withstand actual use
[0203]
(Photoconductor Preparation Example 33)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the support used in Photoconductor Preparation Example 1 was changed to an aluminum cylinder (JIS1050) having a diameter of 30 mm (this is referred to as Photoconductor 33).
[0204]
(Photoconductor Preparation Example 34)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 33 except that Dispersion 4 was used instead of Dispersion 1 used in Photoconductor Preparation Example 33 (this photoconductor is referred to as Photoconductor 34).
[0205]
(Photoconductor Preparation Example 35)
In Photoconductor Preparation Example 33, a photoconductor was prepared in the same manner as Photoconductor Preparation Example 33 except that Dispersion 5 was used instead of Dispersion 1 used (this is referred to as Photoconductor 35).
[0206]
(Example 50 and Comparative Examples 17 and 18)
The photoconductors 33 to 35 produced as described above are mounted on an electrophotographic apparatus cartridge as shown in FIG. 8 and mounted in a tandem full-color image forming apparatus as shown in FIG. 9 (all image forming elements). The same photoconductor is mounted), an image exposure light source is a 780 nm semiconductor laser (image writing by a polygon mirror), and an insulating tape having a thickness of 50 μm is wound around both ends of a charging roller as shown in FIG. 6 as a charging member. An image was output under the following charging conditions using a charging member for close proximity (the space between the photoreceptor and the charging member surface was 50 μm).
<Charging conditions>
DC bias: -800V
AC bias: 2.2 kV (peak to peak), Frequency: 1.5 kHz
[0207]
Using a full color chart with a writing rate of 6%, printing was continuously performed on 5000 sheets, and images at the initial stage and after 5000 sheets were evaluated. In the image evaluation, a white solid image was output at the initial stage and after 5000 sheets, and the background stain was evaluated. Further, the color reproducibility after 5000 sheets was evaluated using a chart for evaluating color reproducibility. The results are shown in Table 8.
[0208]
[Table 8]

<Soil dirt rank>
5: Almost no soiling,
4: Slightly,
3: Actual use limit level,
2 or less: Level that cannot withstand actual use
[0209]
【The invention's effect】
As described above in detail and specifically, according to the present invention, specific conditions (per 1 g of titanyl phthalocyanine crystal) are considered in view of the dispersion of titanyl phthalocyanine crystal, which has low crystal stability and is difficult to be finely divided. The dispersion stress within the predetermined range) was able to eliminate the trade-off relationship between crystal stability and micronization. As a result, a method for producing a dispersion containing a titanyl phthalocyanine crystal having high crystal stability (small crystal transition) and small particle size is provided. This dispersion is rich in storage stability and not only has good film formability, but is also microparticulated while maintaining the characteristic properties of titanyl phthalocyanine crystals. For this reason, the photoconductor produced using this dispersion is a stable electrophotographic photoconductor that does not lose high sensitivity and does not cause a decrease in chargeability and an increase in residual potential even after repeated use. In addition, an electrophotographic photosensitive member that is less likely to cause abnormal images even when used repeatedly is provided.
Furthermore, there are provided a stable electrophotographic apparatus and a process cartridge for an electrophotographic apparatus that are capable of high-speed printing and have few abnormal images.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a bead mill dispersing apparatus used in the present invention.
FIG. 2 is a view showing the inside of a dispersion chamber (72) in FIG.
FIG. 3 is a cross-sectional view showing an electrophotographic photosensitive member of the present invention.
FIG. 4 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member of the present invention.
FIG. 5 is a schematic view for explaining an electrophotographic process and an electrophotographic apparatus of the present invention.
FIG. 6 is a diagram illustrating an example of a proximity charging mechanism in which a gap forming member is disposed on the charging member side.
FIG. 7 shows another example of an electrophotographic process according to the present invention.
FIG. 8 is a diagram showing a general example of the shape of a process cartridge.
FIG. 9 is a schematic view for explaining a tandem full-color electrophotographic apparatus of the present invention.
10 is a graph showing an X-ray diffraction spectrum of a dry powder of water paste obtained in Pigment Preparation Example 1. FIG.
FIG. 11 is a view showing an X-ray diffraction spectrum of Pigment 1;
12 is a view showing an X-ray diffraction spectrum of Comparative Example 2. FIG.
[Explanation of symbols]
1C, 1M, 1Y, 1K photoconductor
2C, 2M, 2Y, 2K charging member
3C, 3M, 3Y, 3K laser light
4C, 4M, 4Y, 4K Development 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 conveyor belt
11C, 11M, 11Y, 11K transfer brush
12 Fixing device
16 photoconductor
17 Charger charger
18 Cleaning brush
19 Image exposure section
20 Developing roller
21 photoconductor
22a Driving roller
22b Driving roller
23 Charger charger
24 Image exposure source
25 Transcription Charger
26 Exposure before cleaning
27 Cleaning brush
28 Static elimination light source
31 Conductive support
35 Charge generation layer
37 Charge transport layer
39 Protective layer
41 photoconductor
42 Static elimination lamp
43 Charging roller
44 Image exposure unit
45 Development unit
46 Pre-transfer charger
47 Registration Roller
48 Transfer paper
49 Transcription Charger
50 Separate charger
51 Separating nails
52 Charger before cleaning
53 Fur Brush
54 Cleaning brush
60 photoconductor
61 Charging roller
62 Gap forming member
63 Metal shaft
64 Image formation area
65 Non-image forming area
71 motor
72 Dispersion chamber
73 Piping
74 Circulation tank
75 Circulation pump
77 Piping
78 Piping
79 Stand for fixing dispersion chamber

Claims (8)

A method for producing a dispersion containing a titanyl phthalocyanine crystal, using a bead mill type dispersion device, having a dispersion media diameter of 0.5 mm or less, a rotor installed in a dispersion chamber having a diameter of 50 mm or less, A method for producing a dispersion, wherein the dispersion stress E given per 1 g of titanyl phthalocyanine crystals subjected to dispersion defined as follows is in the range of 32000 ≦ E ≦ 95000.

Here, T, R, D, W, π, and E are as follows.
T: Dispersion time (minutes)
R: Number of rotor revolutions per unit time (number of revolutions / minute)
D: Rotor diameter (mm)
W: Weight of titanyl phthalocyanine crystal used for dispersion (g)
π: Circumference ratio E: Dispersion stress per gram of titanyl phthalocyanine crystal (mm / g)   The bead mill type disperser is a circulation type disperser, and a ratio of a volume of a solvent used for dispersion and a capacity of a dispersion chamber is in a range of 10: 1 to 50: 1. A method for producing the dispersion described in 1.   The titanyl phthalocyanine crystal has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα. Item 3. A method for producing a dispersion according to Item 1 or 2.   The titanyl phthalocyanine crystal has a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα characteristic X-rays (wavelength 1.542 mm), which is further dominant at 9.4 °, 9.6 °, and 24.0 °. 4. A peak having a peak at 7.3 ° as a diffraction peak at the lowest angle side and having no peak in a range of 7.4 to 9.4 °. A method for producing the described dispersion.   The method for producing a dispersion according to claim 3 or 4, wherein the titanyl phthalocyanine further has no peak at 26.3 °.   The method for producing a dispersion according to any one of claims 1 to 5, wherein at least one selected from a ketone solvent, an ester solvent, and an ether solvent is used as the dispersion solvent.   The method for producing a dispersion according to any one of claims 1 to 6, wherein a binder resin is used in combination when the titanyl phthalocyanine crystal is dispersed.   The method for producing a dispersion according to any one of claims 1 to 7, wherein water is used in combination when the titanyl phthalocyanine crystal is dispersed.

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