JP4886924B2 - Method for producing organic pigment, dispersion for electrophotographic photosensitive member, electrophotographic photosensitive member, electrophotographic method, electrophotographic apparatus, and electrophotographic process cartridge - Google Patents

Description

式中、Ｒ₁、Ｒ₂、Ｒ₃はそれぞれ独立して置換若しくは無置換のアルキル基又はハロゲン原子、Ｒ₄は水素原子又は置換若しくは無置換のアルキル基、Ｒ₅、Ｒ₆は置換若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、又は下記一般式で表わされる２価基を表わす。
【００３０】
【化２】

式中、Ｒ₁₀₁、Ｒ₁₀₂は各々独立して置換若しくは無置換のアルキル基、アリール基又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、分岐状若しくは環状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−、−ＣＯ−、−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（式中Ｚは脂肪族の２価基を表わす。）または、
【００３１】
【化３】

（式中、ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ₁₀₃、Ｒ₁₀₄は置換又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、Ｒ₁₀₁とＲ₁₀₂、Ｒ₁₀₃とＲ₁₀₄は、それぞれ同一でも異なってもよい。
【００３２】
【化４】

式中、Ｒ₇、Ｒ₈は置換若しくは無置換のアリール基、Ａｒ₁、Ａｒ₂、Ａｒ₃は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊ及びｎは、上記（１）式の場合と同じである。
【００３３】
【化５】

式中、Ｒ₉、Ｒ₁₀は置換若しくは無置換のアリール基、Ａｒ₄、Ａｒ₅、Ａｒ₆は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊ及びｎは、上記（１）式の場合と同じである。
【００３４】
【化６】

式中、Ｒ₁₁、Ｒ₁₂は置換若しくは無置換のアリール基、Ａｒ₇、Ａｒ₈、Ａｒ₉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及びｎは、上記（１）式の場合と同じである。
【００３５】
【化７】

式中、Ｒ₁₃、Ｒ₁₄は置換若しくは無置換のアリール基、Ａｒ₁₀、Ａｒ₁₁、Ａｒ₁₂は同一又は異なるアリレン基、Ｘ₁、Ｘ₂は置換若しくは無置換のエチレン基、又は置換若しくは無置換のビニレン基を表わす。Ｘ、ｋ、ｊ及びｎは、上記（１）式の場合と同じである。
【００３６】
【化８】

式中、Ｒ₁₅、Ｒ₁₆、Ｒ₁₇、Ｒ₁₈は置換若しくは無置換のアリール基、Ａｒ₁₃、Ａｒ₁₄、Ａｒ₁₅、Ａｒ₁₆は同一又は異なるアリレン基、Ｙ₁、Ｙ₂、Ｙ₃は単結合、置換若しくは無置換のアルキレン基、置換若しくは無置換のシクロアルキレン基、置換若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及びｎは、上記（１）式の場合と同じである。
【００３７】
【化９】

式中、Ｒ₁₉、Ｒ₂₀は水素原子、置換若しくは無置換のアリール基を表わし、Ｒ₁₉とＲ₂₀は環を形成していてもよい。Ａｒ₁₇、Ａｒ₁₈、Ａｒ₁₉は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊ及びｎは、上記（１）式の場合と同じである。
【００３８】
【化１０】

式中、Ｒ₂₁は置換若しくは無置換のアリール基、Ａｒ₂₀、Ａｒ₂₁、Ａｒ₂₂、Ａｒ₂₃は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊ及びｎは、上記（１）式の場合と同じである。
【００３９】
【化１１】

式中、Ｒ₂₂、Ｒ₂₃、Ｒ₂₄、Ｒ₂₅は置換若しくは無置換のアリール基、Ａｒ₂₄、Ａｒ₂₅、Ａｒ₂₆、Ａｒ₂₇、Ａｒ₂₈は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊ及びｎは、上記（１）式の場合と同じである。
【００４０】
【化１２】

式中、Ｒ₂₆、Ｒ₂₇は置換若しくは無置換のアリール基、Ａｒ₂₉、Ａｒ₃₀、Ａｒ₃₁は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊ及びｎは、上記（１）式の場合と同じである。
【００４１】
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、その使用量として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％程度が適当である。
【００４２】
次に感光層が単層構成（３３）の場合について説明する。上述した特定の方法によって作製された顔料を結着樹脂中に分散した感光体が使用できる。単層感光層は、電荷発生物質及び電荷輸送物質及び結着樹脂を適当な溶剤に溶解ないし分散し、これを塗布、乾燥することによって形成できる。更に、この感光層には上述した電荷輸送材料を添加した機能分離タイプとしてもよく、良好に使用できる。また、必要により、可塑剤やレベリング剤、酸化防止剤等を添加することもできる。
【００４３】
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、電荷発生層（３５）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、更に好ましくは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、ビードコート等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。
【００４４】
本発明における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を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などが挙げられる。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を加えてもよい。これらの下引き層は、前述の感光層の場合と同様、適当な溶媒、塗工法を用いて形成することができる。
【００４５】
さらに、本発明における下引き層として、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Ａｌ₂Ｏ₃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、ＳｉＯ₂、ＳｎＯ₂、ＴｉＯ₂、ＩＴＯ、ＣｅＯ₂等の無機物を真空薄膜作製法にて設けたものも良好に使用できる。この他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。
【００４６】
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、ポリメチルペンテン、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樹脂に酸化チタン、酸化スズ、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。
【００４７】
保護層の形成法としては、通常の塗布法が採用される。なお、保護層の厚さは、０．１〜１０μｍ程度が適当である。また、以上の他に真空薄膜作製法にて形成したａ−Ｃ、ａ−ＳｉＣなど公知の材料も保護層として用いることができる。
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、水酸化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。
【００４８】
以下に、図面を用いて本発明の電子写真方法並びに電子写真装置を詳しく説明する。
図４は、本発明の電子写真プロセス及び電子写真装置の１例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、この電子写真装置は、ドラム状の感光体（１）の上面に、近接しかつ円周に沿って、反時計方向に、除電露光部（２）、帯電チャージャ（３）、イレ−サ（４）、画像露光部（５）、現像ユニット（６）、転写前チャージャ（７）、転写チャージャ（１０）、分離チャージャ（１１）、分離爪（１２）、クリーニング前チャージャ（１３）、ファ−ブラシ（１４）、クリーニンブラシ（１５）を順次付設してなる。さらに転写紙（９）を、感光体（１）と転写チャージャ（１０）および分離チャージャ（１１）の間に送りこむための、レジストロ−ラ（８）を付設している。感光体（１）は、ドラム状の導電性支持体とその上面に密着した感光層からなり、反時計方向に回転する。
【００４９】
上記の電子写真装置を使用した電子写真方法においては、感光体（１）は、反時計方向に回転して、帯電チャージャ（３）で正または負に帯電され、さらにイレ−サ（４）によって、残留トナーが清掃された後、画像露光部（５）からの露光によって、静電潜像を感光体（１）上に形成する。
転写手段には、一般に上記の帯電器が使用できるが、図に示されるように転写チャージャーと分離チャージャーを併用したものが効果的である。
【００５０】
また画像露光部（５）および除電ランプ（２）等で使用する光源としては、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）等の発光物を使用することができる。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に図示した工程の他に、光照射を併用した転写工程、除電工程、クリーニング工程、或いは前露光等の工程を設けることにより、感光体に光が照射される際にも用いることができる。
【００５１】
現像ユニット（６）において、感光体（１）上にトナーを付着させて静電潜像を現像し、転写前チャージャ（７）によって、トナー像の帯電状態を調整した後、転写チャージャ（１０）により転写紙（９）にトナー像を転写し分離チャージャ（１１）によって感光体（１）と転写紙（９）との静電的付着状態を解消し、分離爪（１２）によって転写紙（９）を感光体（１）から分離する。転写紙（９）の分離後、クリーニング前チャージャ（１３）ファーブラシ（１４）およびクリーニンブラシ（１５）により感光体（１）表面を清掃する。このクリーニングは、クリーニングブラシ（１５）だけで、残存するトナーを除去することにより行うこともできる。
【００５２】
感光体に正または負の帯電を施して画像露光を行った場合、感光体上には正または負の静電潜像が形成される。これを、負または正に帯電した極性のトナー（検電微粒子）で現像すれば、ポジ画像が得られるし、逆に正または負に帯電した極性のトナーで現像すれば、ネガ画像が得られる。かかる現像には、公知の方法を適用することができ、また、除電手段にも公知の方法が用いられる。
【００５３】
この例においては導電性支持体はドラム状のものとして示されているが、シート状、エンドレスベルト状のものを使用することができる。クリーニング前チャージャとしては、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）、帯電ローラなどをはじめとする公知の帯電手段を用いることができる。また転写チャージャおよび分離チャージャには、通常上記の帯電手段を、使用することができるが、図５に示すように、転写チャージャと分離チャージャを一体化した帯電器は、効率的で好ましい。クリーニングブラシには、ファーブラシ、マグファーブラシなどをはじめとする公知のものを使用することができる。
【００５４】
図５は、本発明の電子写真方法、及び特に電子写真装置の別の例を説明する概略図を示す。この例においてベルト状の感光体（２１）は、特定の方法により作製された有機顔料を含有する感光層を有しており、駆動ローラ（２２ａ）、（２２ｂ）により駆動され、帯電チャ−ジャ（２３）による帯電、像露光源（２４）による画像露光、現像（図示せず）、転写チャ−ジャ（２５）による転写、クリーニング前露光部（２６）によるクリーニング前露光、クリーニングブラシ（２７）によるクリーニング、除電光源（２８）による除電からなる一連の画像操作が順次繰り返し行われる。なお、この場合クリーニング前露光部の露光は、感光体（２１）の導電性支持体側より行われる。勿論この場合導電性支持体は、透光性である。
【００５５】
以上に図示した電子写真プロセスは、本発明の実施態様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においてクリーニング前露光は、感光層側から行うことができるし、また画像露光部および除電露光部の露光を、導電性支持体側から行うこともできる。
【００５６】
一方、光照射工程としては像露光、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、感光体に本発明の光照射を行なうこともできる。
【００５７】
以上に示すような本発明の画像形成手段は、複写装置、ファクシミリ、プリンタなどの装置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、除電手段などを含んだ一つの装置（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６に示すものが挙げられる。図６に示されるプロセスカートリッジは、感光体（１６）の周囲に配置された帯電チャージャ（１７）、クリーニングブラシ（１８）、画像露光部（１９）、現像ローラ（２０）等からなるコンパクトな構造を有する。感光体（１６）は、導電性支持体上に特定の方法により作製された有機顔料を含有する感光層を有してなるものである。
【００５８】
【実施例】
以下、本発明を実施例を挙げて具体的に説明するが、本発明はこれら実施例により制約を受けるものではない。なお、実施例中の「部」はすべて重量部である。
まず、ブラッグ角２θの最大回析ピークが２７．２°±０．２°にある結晶形（いわゆるＹ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。
【００５９】
実施例１
フタロジニトリル５２５部と、１−クロロナフタレン４０００部を撹拌混合し、窒素気流下で四塩化チタン１９０部を滴下する。滴下終了後、徐々に２００℃まで昇温し、反応温度を１９０℃〜２１０℃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１３０℃になったところ熱時濾過し、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４２２部の粗チタニルフタロシアニン顔料を得た。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１０００ｇに３〜５℃下撹拌、溶解し、濾過した。得られた硫酸溶液を氷水３５リットル中に撹拌しながら滴下し、析出した結晶を濾過、次いで洗浄液が中性になるまで水洗いを繰り返し、チタニルフタロシアニン顔料の水ペーストを得た。この水ペーストに１，２−ジクロロエタン１５００部を更に加え、室温下で２時間撹拌した後、メタノール２５００部を更に加え、撹拌、濾過した。これをメタノール洗浄し、顔料のウェットケーキ９８ｇを得た。このうち５０ｇを大気下（７６０ｍｍＨｇ）で６５℃で乾燥して、チタニルフタロシアニン顔料２４部を得た（ウェットケーキの固形分濃度４８重量％）。
【００６０】
実施例２
実施例１で得た顔料のウェットケーキ４８部を減圧下で６５℃乾燥して、チタニルフタロシアニン顔料２４部を得た（ウェットケーキの固形分濃度４８重量％）。
【００６１】
実施例３
実施例１と同じ方法で作製したウェットケーキ（固形分５９重量％）を減圧下（５ｍｍＨｇ）、６５℃で真空乾燥して、同様にチタニルフタロシアニン顔料を得た。
【００６２】
実施例４
実施例１と同じ方法で作製したウェットケーキ（固形分６８重量％）を減圧下、真空乾燥して、同様にチタニルフタロシアニン顔料を得た。
【００６３】
比較例１
実施例１で得た粗チタニルフタロシアニン３０ｇを実施例１と同様に硫酸処理を行ない、水ペーストを得た。この水ペーストに１，２−ジクロロエタン７５０部を更に加え、室温下で２時間撹拌した後、メタノール１２５０部を更に加え、撹拌、濾過した。これをメタノール洗浄し、顔料のウェットケーキ３３．８ｇを得た。これを減圧下で６５℃で乾燥することにより、チタニルフタロシアニン顔料２５部を得た（ウェットケーキの固形分濃度７４重量％）。
【００６４】
実施例１〜４、及び比較例１で得られた顔料を市販のミキサーを用いて粗粉砕を行なった。実施例１で作製された顔料は約１５秒で、実施例２で作製された顔料は約１０秒で、実施例３で作製された顔料は約２０秒で、実施例４で作製された顔料は約２５秒で、粒径が均一な顔料粉体が得られた。一方、比較例１で作製された顔料は、約１分の粉砕を行なったが、完全な細かい粉体にはならず、大きい塊が残った。
【００６５】
実施例１〜４、及び比較例１で得られたチタニルフタロシアニン顔料についての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
【００６６】
実施例１〜４により得られたチタニルフタロシアニン顔料のＸ線回折スペクトルは全て同じスペクトルであるため、代表例として実施例２で得られた顔料のＸ線回折スペクトルを図７に示す。得られたチタニルフタロシアニン顔料はブラッグ角２θの最大回析ピークが２７．２°±０．２°にある狙い通りの結晶形を有していることがわかる。
【００６７】
一方、比較例１で得られたチタニルフタロシアニン顔料のＸ線回折スペクトルを図８に示す。２７．２°±０．２°のピークの他に、２６．３°±０．２°に見られる他の結晶型（Ａ型あるいはβ型と呼ばれる）を示すピークの存在が認められる。合成過程・硫酸処理過程・結晶変換工程は同様に行なったため、粗粉砕の過程で結晶転移が起こったものと判断される。この原因は、比較例１で作製した顔料が加熱乾燥後に非常に固く締まった状態の結晶となっており、これを粉砕するために非常に強いストレスを必要としたためであると考えられる。
【００６８】
実施例５
下記組成の分散液を以下に示す条件のボールミリングにより作製した（これを分散液１とする）。
実施例１で作製したチタニルフタロシアニン粉末 １．５部
ポリビニルブチラール １部
メチルエチルケトン ８０部
直径５ｍｍのＰＳＺボール６００ｇを入れた直径９０ｍｍのボールミルポット中に、ポリビニルブチラールを溶解したしたメチルエチルケトン及び顔料を全て投入し、６０回転／分の回転数で２時間分散した。
【００６９】
実施例６
下記組成の分散液を、実施例５と同じ条件のボールミリングにより作製した（これを分散液２とする）。
実施例２で作製したチタニルフタロシアニン粉末 １．５部
ポリビニルブチラール １部
メチルエチルケトン ８０部
【００７０】
実施例７
下記組成の分散液を、実施例５と同じ条件のボールミリングにより作製した（これを分散液３とする）。
実施例３で作製したチタニルフタロシアニン粉末 １．５部
ポリビニルブチラール １部
メチルエチルケトン ８０部
【００７１】
実施例８
下記組成の分散液を、実施例５と同じ条件のボールミリングにより作製した（これを分散液４とする）。
実施例４で作製したチタニルフタロシアニン粉末 １．５部
ポリビニルブチラール １部
メチルエチルケトン ８０部
【００７２】
比較例２
下記組成の分散液を、実施例５と同じ条件のボールミリングにより作製した（これを分散液５とする）。
比較例１で作製したチタニルフタロシアニン粉末 １．５部
ポリビニルブチラール １部
メチルエチルケトン ８０部
【００７３】
比較例３
比較例２と同じ組成の分散液を、下記に示す条件のボールミリングにより作製した（これを分散液６とする）。
直径５ｍｍのＰＳＺボール６００ｇを入れた直径９０ｍｍのボールミルポット中に、ポリビニルブチラールを溶解したしたメチルエチルケトン及び顔料を全て投入し、６０回転／分の回転数で１０時間分散した。
【００７４】
実施例５〜８、及び比較例２〜３で作製された分散液中の顔料粒子サイズを堀場製作所：ＣＡＰＡ７００にて測定した。また、作製された分散液を乾固し、粉末にしたものを前述と同様にＸ線回析スペクトルを測定した。結果を合わせて表１に示す。
【００７５】
【表１】

実施例５〜８で作製された分散液は、粒径も細かく、かつ安定した結晶型を有する分散液であることがわかる。
【００７６】
実施例９〜１０、及び比較例４
電鋳ニッケル・ベルト上に下記組成の下引き層塗工液、電荷発生層塗工液、及び電荷輸送層塗工液を順次塗布・乾燥し、積層感光体を作製した。
・下引き層塗工液
二酸化チタン粉末 １５部
ポリビニルブチラール ６部
２−ブタノン １５０部
・電荷発生層塗工液
前述の分散液１、２、６をそれぞれ用いた。
・電荷輸送層塗工液
ポリカーボネート １０部
塩化メチレン ８０部
下記構造式の電荷輸送物質 ７部
【００７７】
【化１３】

このようにしてなる電子写真感光体を図５に示す電子写真プロセス（ただし、クリーニング前露光は無し）に装着し、画像露光光源を７８０ｎｍの半導体レーザ（ポリゴン・ミラーによる画像書き込み）として、現像直前の感光体の表面電位が測定できるように表面電位計のプローブを挿入した。連続して５０００枚の印刷を行ない、そのときの画像露光部と画像非露光部の表面電位を初期と５０００枚後に測定した。結果を表２に示す。
【００７８】
【表２】

表２より、実施例９〜１０の電子写真感光体は繰り返し使用後にも、安定した表面電位を維持していることがわかる。
【００７９】
実施例１１〜１３、及び比較例５
アルミニウムシリンダー表面を陽極酸化処理した後、封孔処理を行なった。この上に、下記組成の電荷発生層塗工液、電荷輸送層塗工液を順次塗布・乾燥して各々０．２μｍの電荷発生層、２０μｍの電荷輸送層を形成し、本発明の電子写真感光体を作製した。
・電荷発生層塗工液
前述の分散液１、３、４、５をそれぞれ用いた。
・電荷輸送層塗工液
ポリカーボネート １０部
塩化メチレン ８０部
下記構造式の電荷輸送物質 ８部
【００８０】
【化１４】

このようにしてなる電子写真感光体を図６に示す電子写真プロセスカートリッジに装着した後、画像形成装置に搭載した。ただし、画像露光光源を７８０ｎｍの半導体レーザ（ポリゴン・ミラーによる画像書き込み）とした。連続して３０００枚の印刷を行ない、初期及び３０００枚目の画像を評価した。結果を表３に示す。
【００８１】
【表３】

表３より、分散液１〜４を用いた場合（実施例１１〜１３）には、初期並びに繰り返し使用後にも良好な画像が得られることがわかる。
【００８２】
実施例１４
実施例９における支持体を電鋳ニッケル・ベルトからアルミシリンダーに変えた以外は、実施例９と全く同様に感光体を作製した。
【００８３】
実施例１５
実施例１４における電荷輸送層塗工液を以下の組成に変えた以外は、実施例１４と全く同様に感光体を作製した。
・電荷輸送層塗工液
塩化メチレン １００部
下記構造式の高分子電荷輸送物質 １０部
【００８４】
【化１５】

【００８５】
実施例１６
実施例１４における電荷輸送層塗工液を以下の組成に変えた以外は、実施例１４と全く同様に感光体を作製した。
・電荷輸送層塗工液
塩化メチレン １００部
下記構造式の高分子電荷輸送物質 １０部
【００８６】
【化１６】

上記の実施例１４〜１６の各電子写真感光体を図４に示す電子写真プロセスに装着し（ただし、画像露光光源を７８０ｎｍに発光を持つＬＤとした）、連続して１万枚の印刷を行ない、その時の画像を初期と１万枚後に評価した。また、電荷輸送層の膜厚の変化（減少量）を測定した。結果を表４に示す。
【００８７】
【表４】

表４から実施例１５〜１６の電子写真感光体は特に優れた耐摩耗性を示していることがわかる。
【００８８】
【発明の効果】
以上、詳細且つ具体的な説明より明らかなように、本発明によれば、分散液作製にあたり、非常に効率的に、かつ結晶型を変えることなく、分散可能な有機顔料を作製する方法が提供される。これを用いることにより、特定の結晶型を維持したまま、粒径の細かい分散液が提供される。この分散液は、電子写真感光体用分散液として非常に有用であり、特定の感光体特性を与え、かつ塗膜欠陥の少ない感光体を作製することが可能である。これにより、特定の特性（高感度・繰り返し使用によっても安定な表面電位）を維持しつつ、耐摩耗性の高い感光体が提供される。更に、高感度を失うことなく、繰り返し使用によっても帯電性の低下と残留電位の上昇を生じない安定な電子写真装置及び電子写真装置用プロセスカートリッジが提供される。
【図面の簡単な説明】
【図１】本発明の感光体の層構造を示す断面図である。
【図２】本発明の感光体の別の層構造を示す断面図である。
【図３】本発明の感光体の更に別の層構造を示す断面図である。
【図４】本発明の電子写真方法及び電子写真装置の例を説明する概略図の１例である。
【図５】本発明の電子写真方法及び電子写真装置の別の例を説明する概略図の別の例である。
【図６】本発明の電子写真方法及び電子写真装置のさらに別の例を説明する概略図の別の例である。
【図７】本発明におけるチタニルフタロシアニン顔料のＸ線回析スペクトルを示す図である。
【図８】比較例におけるチタニルフタロシアニン顔料のＸ線回析スペクトルを示す図である。
【符号の説明】
１ 感光体
２ 除電ランプ
３ 帯電チャージャ
４ イレーサ
５ 画像露光部
６ 現像ユニット
７ 転写前チャージャ
８ レジストロ−ラ
９ 転写紙
１０ 転写チャージャ
１１ 分離チャージャ
１２ 分離爪
１３ クリーニング前チャージャ
１４ ファ−ブラシ
１５ クリーニングブラシ
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−ラ
２２ｂ 駆動ロ−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部
２７ クリーニンブラシ
２８ 除電光源
３１ 導電性支持体
３３ 感光層
３５ 電荷発生層
３７ 電荷輸送層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an organic pigment, an electrophotographic photoreceptor using an organic pigment produced using the same, an electrophotographic method, an electrophotographic apparatus and a process cartridge for the electrophotographic apparatus using the electrophotographic photoreceptor. More specifically, a method for producing an organic pigment having excellent dispersibility and crystal stability and good handleability, and an electrophotographic photoreceptor excellent in stability of charging potential and residual potential even after repeated use, and the same. The present invention relates to an electrophotographic method, an electrophotographic apparatus, and a process cartridge for an electrophotographic apparatus.
[0002]
[Prior art]
Organic pigments have been used as fillers for paints 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 the coating film formed by the wet film formation method is almost dependent on the quality of the dispersion containing the 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.
In order to prepare such a dispersion, various dispersers and dispersion systems have been proposed so far, and methods for increasing the dispersion efficiency have been devised. In order to reduce the particle size of the pigment in the dispersion, generally, a dispersion medium having a small size is used. However, if the pigment is difficult to disperse, the dispersion power is insufficient. The only way to improve this is to increase the media size or use pigments that are easily dispersed. In the former, since the particle size finally reached is limited, it is efficient to develop the latter method. However, in the examination so far, it has been difficult to clearly grasp the relationship between the property / property value of the pigment and the dispersibility, and it is difficult to design a pigment that is easily dispersed at the stage of synthesis.
[0003]
On the other hand, the development of an information processing system using an electrophotographic system is remarkable. In particular, an optical printer that converts information into a digital signal and records information by light is markedly improved in print quality and reliability. This digital recording technique is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, since a variety of information processing functions are added to a conventional copying machine equipped with this digital recording technology for analog copying, it is expected that its demand will increase further in the future.
[0004]
As a light source of an optical printer, a small-sized, inexpensive and highly reliable semiconductor laser (LD) and a light emitting diode (LED) are currently used. The light emission wavelength of the LED that is often used at present is 660 nm, and the light emission wavelength region of the LD is in the near infrared light region. Therefore, development of an electrophotographic photoreceptor having high sensitivity from the visible light region to the near infrared light region is desired.
[0005]
The photosensitive wavelength region of the electrophotographic photosensitive member is almost determined by the photosensitive wavelength region of the charge generating material used in the photosensitive member. Therefore, many charge generating materials such as various azo pigments, polycyclic quinone pigments, trigonal selenium, various phthalocyanine pigments have been developed. Among them, titanyl phthalocyanine (hereinafter abbreviated as TiOPc) exhibits high sensitivity to light having a long wavelength of 600 to 800 nm. Therefore, a photoconductor for an electrophotographic printer or digital copying machine whose light source is an LED or LD. It is extremely important and useful as a material for use.
[0006]
On the other hand, as the conditions of the electrophotographic photosensitive member repeatedly used in the Carlson process and similar processes, the electrostatic characteristics represented by sensitivity, receptive potential, potential retention, potential stability, residual potential, and spectral characteristics are excellent. Is required. In particular, for high-sensitivity photoconductors, it has been empirically known that in many photoconductors, a decrease in chargeability and an increase in residual potential due to repeated use dominate the lifetime characteristics of the photoconductor. Absent. Therefore, it cannot be said that the stability due to repeated use of the photoreceptor using TiOPc is sufficient, and the completion of the technique has been eagerly desired. Further, there has been a demand for a dispersion capable of stably producing a photoconductor having these characteristics over a long period of time.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to propose a method for producing an organic pigment that can be dispersed efficiently when producing a dispersion using the organic pigment. 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 a dispersion capable of stably producing a photoreceptor having the above characteristics for a long period. Another object of the present invention is to provide an electrophotographic photoreceptor having improved wear resistance while maintaining the above characteristics. Furthermore, another object of the present invention is to provide a stable electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge which do not cause a decrease in chargeability and an increase in residual potential even after repeated use without losing high sensitivity. There is.
[0008]
[Means for Solving the Problems]
The dispersibility of the organic pigment can be roughly classified into the grindability and dispersion stability of the pigment. The latter is determined by factors such as the paintability of the pigment and the vehicle, the particle size, and the specific gravity difference between the pigment and the vehicle. On the other hand, the former is determined by the hardness of the pigment under a certain dispersion condition. In other words, the hardness of the pigment can be said to be the bulk density of the pigment.
The bulk density of the pigment is greatly influenced by the density of the pigment itself and the cohesive strength of the pigment. The minimum unit of the organic pigment particles is a primary particle, and interaction between particles is generated by intermolecular hydrogen bonding or the like to form secondary particles in which the primary particles are aggregated. The size of primary particles is almost determined in the process of pigment synthesis unless a means for dissolving the pigment such as acid pasting is used. Since one secondary particle is an aggregate of primary particles, its state can be changed by a post-process of pigment synthesis. The bulk density of the pigment is determined by the packing strength of the secondary particles.
[0009]
As described above, in recent years, organic pigments have been applied as photoelectric conversion materials. In general, materials exhibiting good characteristics have a strong cohesive force and a very strong packing property for secondary particles. For this reason, it is very difficult to produce a good dispersion. Even in the case of materials represented by the same chemical structural formula, there are many cases where only specific crystal forms exhibit specific functions. Such a specific crystal type may easily change due to simple physical and mechanical stress in addition to chemical stress. In such a case, it is not preferable to apply a lot of physical and mechanical stress such as dispersion, and the ability to easily disperse is an effective means for undoubtedly expressing a specific function.
[0010]
The present invention is a method for producing a pigment exhibiting good dispersion characteristics, and its feature is that the packing strength of the secondary particles is as much as possible while maintaining the primary particles and crystal form of the pigment powder (including the case of agglomerates). The present invention relates to a method for producing an organic pigment that can be easily dispersed to the primary particle level without changing the crystal form when producing a dispersion liquid by controlling in a weakening direction.
[0011]
Thus, according to the present invention, (1) “ In the method for producing titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ of at least 27.2 ° ± 0.2 ° with respect to a characteristic X-ray of Cu—Kα (wavelength 1.541１．５), the titanyl phthalocyanine At least the final process of production Organic From contact with solvent Titanyl phthalocyanine Is the process of taking out The Removed by filtration Organic In wet cake containing solvent The titanyl phthalocyanine Solid content concentration 48% by weight or more 68 In a state of weight% or less Under a reduced pressure of 10 mmHg or less, Above room temperature 65 ° C or less Heat drying at a temperature of Titanyl phthalocyanine Manufacturing method ", ( 2 ) "At least in the solvent Titanyl phthalocyanine with a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° ± 0.2 ° for at least Cu-Kα characteristic X-rays (wavelength 1.541 波長) Is a dispersion for an electrophotographic photosensitive member, and is contained in the dispersion The titanyl phthalocyanine But, Titanyl phthalocyanine At least as the final step of production Organic From contact with solvent Titanyl phthalocyanine And removed by filtration Organic In wet cake containing solvent Titanyl phthalocyanine Solid content concentration 48% by weight or more 68 In a state of weight% or less Under a reduced pressure of 10 mmHg or less, Above room temperature 65 ° C or less Dried at a temperature of Titanyl phthalocyanine A dispersion for an electrophotographic photosensitive member characterized by 3 ) "On a conductive support Contains at least titanyl phthalocyanine having a Bragg angle 2θ maximum diffraction peak of 27.2 ° ± 0.2 ° with respect to the characteristic X-ray (wavelength 1.541 （) of Cu-Kα Has a photosensitive layer and is contained in the photosensitive layer Titanyl phthalocyanine But, Titanyl phthalocyanine At least as the final step of production Organic From contact with solvent Titanyl phthalocyanine In a wet cake containing an organic solvent removed by filtration Titanyl phthalocyanine Solid content concentration 48% by weight or more 68 In a state of weight% or less Under a reduced pressure of 10 mmHg or less, Above room temperature 65 ° C or less Dried at a temperature of Titanyl phthalocyanine An electrophotographic photoreceptor characterized by 4 ) “The photosensitive layer comprises a laminate structure of a charge generation layer and a charge transport layer, 3 Electrophotographic photosensitive member according to item), ( 5 ) “The charge transport layer contains a polycarbonate having at least a triarylamine structure in the main chain and / or side chain ( 4 Electrophotographic photosensitive member according to item), ( 6 ) “In an electrophotographic method in which at least charging, image exposure, development, transfer, cleaning, and static elimination are repeated on an electrophotographic photosensitive member, the electrophotographic photosensitive member includes: Titanyl phthalocyanine with a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° ± 0.2 ° for at least Cu-Kα characteristic X-rays (wavelength 1.541 波長) At least as the final step of production Organic From contact with solvent Titanyl phthalocyanine And removed by filtration Organic In wet cake containing solvent Titanyl phthalocyanine Solid content concentration 48% by weight or more 68 In a state of weight% or less Under a reduced pressure of 10 mmHg or less, Above room temperature 65 ° C or less Dried at a temperature of Titanyl phthalocyanine An electrophotographic method characterized by comprising a photosensitive layer containing a photoconductive layer on a conductive support ", ( 7 ) “An electrophotographic apparatus comprising at least a charging means, an image exposing means, a developing means, a transferring means, a cleaning means, a charge eliminating means, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member comprises: Titanyl phthalocyanine with a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° ± 0.2 ° for at least Cu-Kα characteristic X-rays (wavelength 1.541 波長) At least as the final step of production Organic From contact with solvent Titanyl phthalocyanine And removed by filtration Organic In wet cake containing solvent Titanyl phthalocyanine Solid content concentration 48% by weight or more 68 In a state of weight% or less Under a reduced pressure of 10 mmHg or less, Above room temperature 65 ° C or less Dried at a temperature of Titanyl phthalocyanine An electrophotographic apparatus characterized in that a photosensitive layer containing is provided on a conductive support ”, ( 8 ) “A process cartridge for an electrophotographic apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member comprises: Titanyl phthalocyanine with a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° ± 0.2 ° for at least Cu-Kα characteristic X-rays (wavelength 1.541 波長) At least as the final step of production Organic From contact with solvent Titanyl phthalocyanine And removed by filtration Organic In wet cake containing solvent Titanyl phthalocyanine Solid content concentration 48% by weight or more 68 In a state of weight% or less Under a reduced pressure of 10 mmHg or less, Above room temperature 65 ° C or less Dried at a temperature of Titanyl phthalocyanine There is provided a process cartridge for an electrophotographic apparatus characterized in that a photosensitive layer containing is provided on a conductive support.
[0012]
Hereinafter, the present invention will be described in detail.
Organic pigments are generally synthesized by a wet method and are often handled in a state where the pigment is suspended in a solvent, such as washing, purification, and crystal conversion. From this state, only the target pigment is taken out, but various methods such as filtration and centrifugation are used. In this step, if the solid content concentration of the pigment is a certain weight% or more, and in most cases about 70% by weight or more for organic pigments, a very tight pigment (high bulk density) is produced. As described above, such a pigment has poor coarse pulverization or dispersion efficiency. Therefore, it is necessary to apply a large physical and mechanical stress. As a result, there may be a problem that the crystal type changes.
On the other hand, when the solid content concentration of the pigment is 70 wt% or less, the solvent is sufficiently contained, and the bulk density is not so large in this state. The pigment in this state is immediately heated and dried at a temperature equal to or higher than room temperature to produce a pigment having a small bulk density. It has been found that if this drying step is performed under a reduced pressure of 10 mmHg or less, this effect becomes even more remarkable, and the present invention has been completed. As described above, the solid content concentration of the pigment is desirably 70% by weight or less, but if the concentration is too low, the handleability becomes difficult. Therefore, an appropriate concentration may be selected from the handling property, but generally about 20% by weight or more is appropriate.
That is, although it depends on the cohesiveness of the pigment in the wet cake, the cohesiveness is strong and the thixotropic property is high, the viscosity is high, and the handleability is good even at a considerably low concentration, but it seems to be close to Newton's property. In such a case, if the pigment concentration is too low, the handleability is poor, so it is necessary to set the concentration relatively high. Therefore, it is preferable to set an appropriate pigment concentration by confirming experimentally in advance.
[0013]
Any of the known organic pigments can be used as the organic pigment produced in the present invention. For example, phthalocyanine pigments, monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, Examples thereof include quinone-based condensed polycyclic compounds, squaric acid-based dyes, naphthalocyanine-based pigments, and azulenium salt-based dyes.
[0014]
A phthalocyanine pigment having a large number of crystal types is very effective. In particular, titanyl phthalocyanine is a pigment whose characteristics vary greatly depending on the crystal type. In particular, the characteristic X-ray of Cu-Kα (wavelength 1.5 41 Titanyl phthalocyanine having a maximum diffraction peak of 27.2 ° ± 0.2 ° with respect to ii) has a very high photocarrier generation ability, but its crystal form is unstable, and other crystal forms Can be easily converted. However, by using the present invention, a dispersion can be produced while maintaining the crystal form stably.
[0015]
Any known dryer can be used for heating and drying the pigment at room temperature or higher. However, when it is performed in the air, a blower-type dryer is preferable. 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, this is an effective means for a material that decomposes at a high temperature or changes in crystal form. In the present invention, “under reduced pressure of 10 mmHg or less” refers to a state where the degree of vacuum is higher than 10 mmHg.
[0016]
Next, the dispersion for an electrophotographic photoreceptor of the present invention will be described. The dispersion for electrophotography has very strict specifications, unlike the dispersion used for ordinary paints. For example, in the case where a specific pigment or a pigment having a specific crystal type has a desired function for the first time, the dispersion must be prepared in a state in which the crystal type remains. In recent electrophotographic processes, the resolution of an image is very important, and the particle size of the pigment contained in the photoreceptor must be small accordingly. In order to produce such a dispersion, it is necessary to produce a pigment with good dispersibility from the beginning. As a result of studying with this point in mind, it was found that by using a pigment having a low bulk density as described above, a dispersion having a small ultimate particle size can be produced without changing the crystal form.
Regarding the preparation of the dispersion, a general method is used, and the pigment is obtained by dispersing the pigment in a suitable solvent together with a binder resin using a ball mill, an attritor, a sand mill, an ultrasonic wave, or the like. Is. At this time, the binder resin may be selected depending on the electrostatic characteristics of the photoreceptor, and the solvent may be selected depending on the wettability to the pigment, the dispersibility of the pigment, and the like.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an electrophotographic photosensitive member used in the present invention. A single-layer photosensitive layer (33) mainly composed of a charge generating material and a charge transporting material is formed on a conductive support (31). Is provided.
FIG. 2 and FIG. 3 are cross-sectional views showing another configuration example of the electrophotographic photosensitive member used in the present invention, in which a charge generation layer (35) mainly composed of a charge generation material and a charge transport material as a main component. And a charge transport layer (37) having a laminated structure.
[0018]
The conductive support (31) has a volume resistance of 10 ^Ten A material exhibiting conductivity of Ωcm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, a metal oxide such as tin oxide, indium oxide, or the like by vapor deposition or sputtering. Cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc., and extruding them, making them into bare tubes by methods such as drawing, and then surface-treating them by cutting, superfinishing, polishing, etc. A tube or the like can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can be used as the conductive support (31).
[0019]
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 is formed by dispersing the conductive powder and the binder resin in a suitable solvent such as THF (tetrahydrofuran), MDC (dichloromethane), MEK (methyl ethyl ketone), toluene, and the like. Can be provided.
Furthermore, it is electrically conductive by 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, Teflon (trade name) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support (31) of the present invention.
[0020]
Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a laminate, but for convenience of explanation, the case where it is composed of a charge generation layer (35) and a charge transport layer (37) will be described first.
In the charge generation layer (35), the pigment is taken out from at least the state in contact with the solvent as a final step of preparing the pigment as the charge generation material, and the pigment solid content concentration in the wet cake containing the solvent is 70% by weight or less. Among these layers, the organic pigment is heated and dried at a temperature of room temperature or higher.
For the charge generation layer (35), the pigment is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is applied onto a conductive support, It is formed by drying.
[0021]
As the binder resin used for the charge generation layer (35) as necessary, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly -N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulosic resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone Etc. The amount of the binder resin is 0 to 500 parts by weight, preferably 0 to 300 parts by weight, per 100 parts by weight of the charge generating material.
[0022]
Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. As a coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used. The film thickness of the charge generation layer (35) is suitably about 0.01-5 μm, preferably 0.1-2 μm.
[0023]
The charge transport layer (37) can be formed by dissolving or dispersing the charge transport material and the 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.
[0024]
Charge transport materials include hole transport materials and electron transport materials.
Examples of the electron transport material include chloroanil, bromanyl, 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- Examples thereof include electron-accepting substances such as trinitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.
[0025]
The hole transport materials include poly-N-carbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, oxalates. Diazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives , Divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., other known materials such as bisstilbene derivatives, enamine derivatives, etc. Charge.
These charge transport materials may be used alone or in combination of two or more.
[0026]
As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, Examples thereof include thermoplastic resins such as phenol resins and alkyd resins, and thermosetting resins.
[0027]
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight with respect to 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.
[0028]
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. A known material can be used as the polymer charge transporting material, but a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, polymer charge transport materials represented by the following formulas (1) to (10) are favorably used, and these are exemplified below and specific examples are shown.
[0029]
[Chemical 1]

Where R ₁ , R ₂ , R _Three Each independently represents a substituted or unsubstituted alkyl group or a halogen atom, R _Four Is a hydrogen atom or a substituted or unsubstituted alkyl group, R _Five , 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.
[0030]
[Chemical formula 2]

Where 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
[0031]
[Chemical 3]

(Wherein, a is an integer of 1 to 20, b is an integer of 1 to 2000, R ₁₀₃ , R ₁₀₄ Represents a substituted or unsubstituted alkyl group or aryl group. ). Where R ₁₀₁ And R ₁₀₂ , R ₁₀₃ And R ₁₀₄ May be the same or different.
[0032]
[Formula 4]

Where R ₇ , R ₈ Is a substituted or unsubstituted aryl group, Ar ₁ , Ar ₂ , Ar _Three Represent the same or different arylene groups. X, k, j, and n are the same as those in the above formula (1).
[0033]
[Chemical formula 5]

Where R ₉ , R _Ten Is a substituted or unsubstituted aryl group, Ar _Four , Ar _Five , Ar ₆ Represent the same or different arylene groups. X, k, j, and n are the same as those in the above formula (1).
[0034]
[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 those in the above formula (1).
[0035]
[Chemical 7]

Where R ₁₃ , R ₁₄ Is a substituted or unsubstituted aryl group, Ar _Ten , 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 those in the above formula (1).
[0036]
[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 _Three 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 those in the above formula (1).
[0037]
[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 those in the above formula (1).
[0038]
[Chemical Formula 10]

Where R _{twenty one} Is a substituted or unsubstituted aryl group, Ar ₂₀ , Ar _{twenty one} , Ar _{twenty two} , Ar _{twenty three} Represent the same or different arylene groups. X, k, j, and n are the same as those in the above formula (1).
[0039]
Embedded image

Where R _{twenty two} , R _{twenty three} , R _{twenty four} , R _{twenty five} Is a substituted or unsubstituted aryl group, Ar _{twenty four} , Ar _{twenty five} , Ar ₂₆ , Ar ₂₇ , Ar ₂₈ Represent the same or different arylene groups. X, k, j, and n are the same as those in the above formula (1).
[0040]
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 those in the above formula (1).
[0041]
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 with respect to the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 1 weight with respect to the binder resin. % Is appropriate.
[0042]
Next, the case where the photosensitive layer has a single layer configuration (33) will be described. A photoreceptor in which a pigment prepared by the above-described specific method is dispersed in a binder resin can be used. The single-layer photosensitive layer can be formed by dissolving or dispersing a charge generating substance, a charge transporting substance and a binder resin in a suitable solvent, and applying and drying them. Further, the photosensitive layer may be a function separation type to which the above-described charge transport material is added, and can be used satisfactorily. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
[0043]
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 charge generation layer (35) may be mixed and used. Of course, the polymer charge transport materials mentioned above can also be used favorably. The amount of the charge generation 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 transport 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, bead coat or the like. The thickness of the single photosensitive layer is suitably about 5 to 100 μm.
[0044]
In the electrophotographic photoreceptor 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 is a resin having a high solvent resistance to general organic solvents. Is 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 curable resins that form a three-dimensional network structure such as resins. In order to prevent moiré and reduce the residual potential, the undercoat layer may contain metal oxide fine powders exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like. These undercoat layers can be formed using an appropriate solvent and coating method as in the case of the photosensitive layer described above.
[0045]
Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer in the present invention. In addition, the undercoat layer of the present invention is made of Al. ₂ O _Three Anodic oxidation, organic materials such as polyparaxylylene (parylene), 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.
[0046]
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, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, Examples of the resin include polyvinylidene chloride and epoxy resin. Other protective layers include fluorine resins such as polytetrafluoroethylene, silicone resins, and those obtained by dispersing inorganic materials such as titanium oxide, tin oxide, and potassium titanate in these resins for the purpose of improving wear resistance. Can be added.
[0047]
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 manufacturing method can also be used as the protective layer.
In the present invention, an intermediate layer can 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, polyvinyl hydroxide 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.
[0048]
Hereinafter, an electrophotographic method and an electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 4 is a schematic diagram for explaining an example of the electrophotographic process and the electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.
In FIG. 5, the electrophotographic apparatus is close to the upper surface of the drum-shaped photoconductor (1) and is counterclockwise along the circumference, in the antistatic exposure portion (2), the charging charger (3), the eraser. -(4), image exposure unit (5), development unit (6), pre-transfer charger (7), transfer charger (10), separation charger (11), separation claw (12), pre-cleaning charger (13) A fur brush (14) and a cleaning brush (15) are sequentially provided. Further, a registration roller (8) for feeding the transfer paper (9) between the photosensitive member (1), the transfer charger (10) and the separation charger (11) is provided. The photoreceptor (1) is composed of a drum-shaped conductive support and a photosensitive layer in close contact with the upper surface thereof, and rotates counterclockwise.
[0049]
In the electrophotographic method using the above-described electrophotographic apparatus, the photosensitive member (1) rotates counterclockwise, is charged positively or negatively by the charging charger (3), and is further charged by the eraser (4). After the residual toner is cleaned, an electrostatic latent image is formed on the photoreceptor (1) by exposure from the image exposure unit (5).
As the transfer means, the above charger can be generally used. However, as shown in the figure, a combination of a transfer charger and a separation charger is effective.
[0050]
The light source used in the image exposure unit (5) and the charge removal lamp (2) is a fluorescent lamp, tungsten lamp, halogen lamp, mercury lamp, sodium lamp, light emitting diode (LED), semiconductor laser (LD), electroluminescence ( EL) or the like can be used. 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 is provided when a photoconductor is irradiated 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 illustrated in FIG. Can also be used.
[0051]
In the developing unit (6), the electrostatic latent image is developed by attaching toner onto the photosensitive member (1), and the charged state of the toner image is adjusted by the pre-transfer charger (7), and then the transfer charger (10). Then, the toner image is transferred onto the transfer paper (9), the electrostatic charger (1) is removed from the transfer paper (9) by the separation charger (11), and the transfer paper (9) is removed by the separation claw (12). ) Is separated from the photoreceptor (1). After the transfer paper (9) is separated, the surface of the photoreceptor (1) is cleaned by the pre-cleaning charger (13), the fur brush (14) and the cleaning brush (15). This cleaning can also be performed by removing the remaining toner using only the cleaning brush (15).
[0052]
When image exposure is performed by positively or negatively charging the photoconductor, a positive or negative electrostatic latent image is formed on the photoconductor. A positive image can be obtained by developing this with negative or positively charged toner (electric detection fine particles), and a negative image can be obtained by developing it with positively or negatively charged toner. . A known method can be applied to the development, and a known method is also used for the charge eliminating means.
[0053]
In this example, the conductive support is shown as a drum, but a sheet or endless belt can be used. As the pre-cleaning charger, known charging means such as a corotron, a scorotron, a solid charger (solid state charger), a charging roller and the like can be used. In addition, the above charging means can usually be used for the transfer charger and the separation charger. However, as shown in FIG. 5, a charger in which the transfer charger and the separation charger are integrated is efficient and preferable. As the cleaning brush, known ones such as a fur brush and a mag fur brush can be used.
[0054]
FIG. 5 shows a schematic diagram illustrating another example of the electrophotographic method of the present invention, and in particular, an electrophotographic apparatus. In this example, the belt-like photoreceptor (21) has a photosensitive layer containing an organic pigment produced by a specific method, and is driven by driving rollers (22a) and (22b) to be charged charger. Charging by (23), image exposure by image exposure source (24), development (not shown), transfer by transfer charger (25), exposure before cleaning by exposure unit (26) before cleaning, cleaning brush (27) A series of image operations consisting of cleaning by the above and discharging by the discharging light source (28) are sequentially repeated. In this case, the exposure of the pre-cleaning exposure part is performed from the conductive support side of the photoreceptor (21). Of course, in this case, the conductive support is translucent.
[0055]
The electrophotographic process illustrated above exemplifies an embodiment of the present invention, and of course other embodiments are possible. For example, in FIG. 5, the pre-cleaning exposure can be performed from the photosensitive layer side, and the exposure of the image exposure unit and the discharge exposure unit can be performed from the conductive support side.
[0056]
On the other hand, as the light irradiation process, image exposure, pre-cleaning exposure, and static elimination exposure are shown in the figure. The light irradiation of the invention can also be performed.
[0057]
The image forming means of the present invention as described above may be fixedly incorporated in an apparatus such as a copying apparatus, a facsimile machine, 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 further includes a charging means, an exposure means, a developing means, a transfer means, a cleaning means, a static elimination means, and the like. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. The process cartridge shown in FIG. 6 has a compact structure including a charging charger (17), a cleaning brush (18), an image exposure unit (19), a developing roller (20) and the like disposed around the photosensitive member (16). Have The photoreceptor (16) has a photosensitive layer containing an organic pigment prepared by a specific method on a conductive support.
[0058]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not restrict | limited by these Examples. In the examples, all “parts” are parts by weight.
First, a specific synthesis example of a crystal form (so-called Y-type) titanyl phthalocyanine pigment having a maximum diffraction peak of Bragg angle 2θ of 27.2 ° ± 0.2 ° will be described.
[0059]
Example 1
525 parts of phthalodinitrile and 4000 parts of 1-chloronaphthalene are stirred and mixed, and 190 parts of titanium tetrachloride are 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 5 hours while keeping the reaction temperature between 190 ° C. and 210 ° 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 heated with hot water at 80 ° C. And dried several times to obtain 422 parts of a crude titanyl phthalocyanine pigment. 60 parts of the obtained crude titanyl phthalocyanine pigment washed with hot water was stirred and dissolved in 1000 g of 96% sulfuric acid at 3 to 5 ° C. and filtered. The obtained sulfuric acid solution was dropped into 35 liters of ice water while 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 1,2-dichloroethane was further added and stirred at room temperature for 2 hours, and then 2500 parts of methanol was further added, stirred and filtered. This was washed with methanol to obtain 98 g of a pigment wet cake. 50 g of this was dried at 65 ° C. in the atmosphere (760 mmHg) to obtain 24 parts of a titanyl phthalocyanine pigment (solid content concentration of wet cake of 48% by weight).
[0060]
Example 2
48 parts of the pigment wet cake obtained in Example 1 was dried at 65 ° C. under reduced pressure to obtain 24 parts of a titanyl phthalocyanine pigment (solid content concentration of the wet cake was 48% by weight).
[0061]
Example 3
A wet cake (solid content: 59% by weight) prepared by the same method as in Example 1 was vacuum dried at 65 ° C. under reduced pressure (5 mmHg) to obtain a titanyl phthalocyanine pigment in the same manner.
[0062]
Example 4
A wet cake (solid content 68 wt%) prepared in the same manner as in Example 1 was vacuum dried under reduced pressure to obtain a titanyl phthalocyanine pigment in the same manner.
[0063]
Comparative Example 1
30 g of the crude titanyl phthalocyanine obtained in Example 1 was treated with sulfuric acid in the same manner as in Example 1 to obtain a water paste. After further adding 750 parts of 1,2-dichloroethane to this water paste and stirring at room temperature for 2 hours, 1250 parts of methanol was further added, followed by stirring and filtration. This was washed with methanol to obtain 33.8 g of a pigment wet cake. This was dried at 65 ° C. under reduced pressure to obtain 25 parts of titanyl phthalocyanine pigment (solid content concentration of wet cake: 74% by weight).
[0064]
The pigments obtained in Examples 1 to 4 and Comparative Example 1 were coarsely pulverized using a commercially available mixer. The pigment made in Example 1 was about 15 seconds, the pigment made in Example 2 was about 10 seconds, the pigment made in Example 3 was about 20 seconds, and the pigment made in Example 4 In about 25 seconds, a pigment powder having a uniform particle size was obtained. On the other hand, the pigment prepared in Comparative Example 1 was pulverized for about 1 minute, but did not become a complete fine powder, and a large lump remained.
[0065]
X-ray diffraction spectra of the titanyl phthalocyanine pigments obtained in Examples 1 to 4 and Comparative Example 1 were measured under the following conditions.
X-ray tube: Cu
Voltage: 40 kV
Current: 20 mA
Scanning speed: 1 ° / min
Scanning range: 3 ° -40 °
Time constant: 2 seconds
[0066]
Since the X-ray diffraction spectra of the titanyl phthalocyanine pigments obtained in Examples 1 to 4 are all the same spectrum, the X-ray diffraction spectrum of the pigment obtained in Example 2 is shown in FIG. 7 as a representative example. It can be seen that the obtained titanyl phthalocyanine pigment has a desired crystal form with a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° ± 0.2 °.
[0067]
On the other hand, the X-ray diffraction spectrum of the titanyl phthalocyanine pigment obtained in Comparative Example 1 is shown in FIG. In addition to the peak at 27.2 ° ± 0.2 °, the presence of a peak showing another crystal type (referred to as A-type or β-type) seen at 26.3 ° ± 0.2 ° is observed. Since the synthesis process, sulfuric acid treatment process, and crystal conversion process were performed in the same manner, it is determined that crystal transition occurred during the coarse pulverization process. This is considered to be because the pigment prepared in Comparative Example 1 is a crystal that is very tight after heating and drying, and a very strong stress is required to pulverize the crystal.
[0068]
Example 5
A dispersion having the following composition was prepared by ball milling under the following conditions (this is referred to as Dispersion 1).
1.5 parts of titanyl phthalocyanine powder prepared in Example 1
Polyvinyl butyral 1 part
80 parts of methyl ethyl ketone
All of methyl ethyl ketone and pigment in which polyvinyl butyral was dissolved were put into a 90 mm diameter ball mill pot containing 600 g of 5 mm diameter PSZ balls, and dispersed for 2 hours at a rotation speed of 60 rotations / minute.
[0069]
Example 6
A dispersion having the following composition was prepared by ball milling under the same conditions as in Example 5 (this is referred to as Dispersion 2).
1.5 parts of titanyl phthalocyanine powder prepared in Example 2
Polyvinyl butyral 1 part
80 parts of methyl ethyl ketone
[0070]
Example 7
A dispersion having the following composition was prepared by ball milling under the same conditions as in Example 5 (this is referred to as Dispersion 3).
1.5 parts of titanyl phthalocyanine powder prepared in Example 3
Polyvinyl butyral 1 part
80 parts of methyl ethyl ketone
[0071]
Example 8
A dispersion having the following composition was prepared by ball milling under the same conditions as in Example 5 (this is referred to as Dispersion 4).
1.5 parts of titanyl phthalocyanine powder prepared in Example 4
Polyvinyl butyral 1 part
80 parts of methyl ethyl ketone
[0072]
Comparative Example 2
A dispersion having the following composition was prepared by ball milling under the same conditions as in Example 5 (this is referred to as Dispersion 5).
1.5 parts of titanyl phthalocyanine powder prepared in Comparative Example 1
Polyvinyl butyral 1 part
80 parts of methyl ethyl ketone
[0073]
Comparative Example 3
A dispersion having the same composition as Comparative Example 2 was prepared by ball milling under the conditions shown below (this is referred to as Dispersion 6).
Into a 90 mm diameter ball mill pot containing 600 g of 5 mm diameter PSZ balls, all of methyl ethyl ketone and pigment dissolved with polyvinyl butyral were charged and dispersed for 10 hours at a rotation speed of 60 rpm.
[0074]
The pigment particle sizes in the dispersions prepared in Examples 5 to 8 and Comparative Examples 2 to 3 were measured with Horiba: CAPA700. Further, the prepared dispersion was solidified and powdered, and an X-ray diffraction spectrum was measured in the same manner as described above. The results are shown in Table 1.
[0075]
[Table 1]

It can be seen that the dispersions prepared in Examples 5 to 8 are fine dispersions and have a stable crystal form.
[0076]
Examples 9 to 10 and Comparative Example 4
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 onto an electroformed nickel belt and dried to prepare a laminated photoreceptor.
・ Undercoat layer coating solution
Titanium dioxide powder 15 parts
Polyvinyl butyral 6 parts
2-butanone 150 parts
-Charge generation layer coating solution
The above dispersions 1, 2, and 6 were used, respectively.
・ Charge transport layer coating solution
10 parts of polycarbonate
80 parts of methylene chloride
7 parts of charge transport material with the following structural formula
[0077]
Embedded image

The electrophotographic photosensitive member thus formed is mounted on the electrophotographic process shown in FIG. 5 (no exposure before cleaning), and the image exposure light source is a 780 nm semiconductor laser (image writing by a polygon mirror). A surface potential meter probe was inserted so that the surface potential of the photoconductor could be measured. 5000 sheets were continuously printed, and the surface potentials of the image exposure part and the image non-exposure part at that time were measured initially and after 5000 sheets. The results are shown in Table 2.
[0078]
[Table 2]

From Table 2, it can be seen that the electrophotographic photoreceptors of Examples 9 to 10 maintain a stable surface potential even after repeated use.
[0079]
Examples 11 to 13 and Comparative Example 5
The aluminum cylinder surface was anodized and then sealed. On top of this, a charge generation layer coating solution and a charge transport layer coating solution having the following composition are sequentially applied and dried to form a 0.2 μm charge generation layer and a 20 μm charge transport layer, respectively. A photoconductor was prepared.
-Charge generation layer coating solution
The aforementioned dispersions 1, 3, 4, and 5 were used, respectively.
・ Charge transport layer coating solution
10 parts of polycarbonate
80 parts of methylene chloride
8 parts of charge transport material of the following structural formula
[0080]
Embedded image

The electrophotographic photosensitive member thus formed was mounted on the electrophotographic process cartridge shown in FIG. 6 and then mounted on the image forming apparatus. However, the image exposure light source was a semiconductor laser of 780 nm (image writing by a polygon mirror). 3000 sheets were continuously printed, and the initial and 3000th images were evaluated. The results are shown in Table 3.
[0081]
[Table 3]

From Table 3, it can be seen that when dispersions 1 to 4 are used (Examples 11 to 13), good images can be obtained at the initial stage and after repeated use.
[0082]
Example 14
A photoconductor was prepared in exactly the same manner as in Example 9, except that the support in Example 9 was changed from an electroformed nickel belt to an aluminum cylinder.
[0083]
Example 15
A photoconductor was prepared in exactly the same manner as in Example 14, except that the charge transport layer coating solution in Example 14 was changed to the following composition.
・ Charge transport layer coating solution
100 parts methylene chloride
10 parts of polymer charge transport material of the following structural formula
[0084]
Embedded image

[0085]
Example 16
A photoconductor was prepared in exactly the same manner as in Example 14, except that the charge transport layer coating solution in Example 14 was changed to the following composition.
・ Charge transport layer coating solution
100 parts methylene chloride
10 parts of polymer charge transport material of the following structural formula
[0086]
Embedded image

Each of the electrophotographic photoreceptors of Examples 14 to 16 was mounted on the electrophotographic process shown in FIG. 4 (however, the image exposure light source was an LD having a light emission at 780 nm), and 10,000 sheets were printed continuously. The image at that time was evaluated after the initial and 10,000 sheets. Further, the change (decrease amount) in the thickness of the charge transport layer was measured. The results are shown in Table 4.
[0087]
[Table 4]

It can be seen from Table 4 that the electrophotographic photoreceptors of Examples 15 to 16 exhibit particularly excellent wear resistance.
[0088]
【Effect of the invention】
As described above, as is clear from the detailed and specific description, according to the present invention, there is provided a method for producing a dispersible organic pigment very efficiently and without changing the crystal form in producing a dispersion. Is done. By using this, a dispersion having a fine particle size is provided while maintaining a specific crystal form. This dispersion is very useful as a dispersion for an electrophotographic photoreceptor, and can provide a photoreceptor having specific photoreceptor characteristics and few coating film defects. This provides a photoconductor having high wear resistance while maintaining specific characteristics (high sensitivity and stable surface potential even after repeated use). Furthermore, there is provided a stable electrophotographic apparatus and a process cartridge for an electrophotographic apparatus that do not cause a decrease in chargeability and an increase in residual potential even after repeated use without losing high sensitivity.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a layer structure of a photoreceptor of the present invention.
FIG. 2 is a cross-sectional view showing another layer structure of the photoreceptor of the present invention.
FIG. 3 is a cross-sectional view showing still another layer structure of the photoreceptor of the present invention.
FIG. 4 is an example of a schematic diagram illustrating an example of an electrophotographic method and an electrophotographic apparatus of the present invention.
FIG. 5 is another example of a schematic diagram illustrating another example of the electrophotographic method and the electrophotographic apparatus of the present invention.
FIG. 6 is another example of a schematic diagram illustrating still another example of the electrophotographic method and the electrophotographic apparatus of the present invention.
FIG. 7 is a diagram showing an X-ray diffraction spectrum of a titanyl phthalocyanine pigment in the present invention.
FIG. 8 is an X-ray diffraction spectrum of a titanyl phthalocyanine pigment in a comparative example.
[Explanation of symbols]
1 Photoconductor
2 Static elimination lamp
3 Charger charger
4 Eraser
5 Image exposure section
6 Development unit
7 Charger before transfer
8 Registrar Roller
9 Transfer paper
10 Transcription charger
11 Separate charger
12 Separating nails
13 Charger before cleaning
14 Far Brush
15 Cleaning brush
16 photoconductor
17 Charger charger
18 Cleaning brush
19 Image exposure unit
20 Development roller
21 photoconductor
22a Drive roller
22b Drive roller
23 Charger charger
24 Image exposure source
25 Transcription Charger
26 Exposure section before cleaning
27 Cleanin Brush
28 Static elimination light source
31 Conductive support
33 Photosensitive layer
35 Charge generation layer
37 Charge transport layer

Claims (8)

In the method for producing titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ of at least 27.2 ° ± 0.2 ° with respect to at least Cu-Kα characteristic X-ray (wavelength 1.541Å) , the final step of producing the titanyl phthalocyanine comprises At least step der that from the contact state with the organic solvent taken out titanyl phthalocyanine is, while the titanyl phthalocyanine solid concentration following 68 wt% or more 48 wt% state during wet cake containing organic solvent taken out by filtration A method for producing titanyl phthalocyanine , which comprises heat drying at a temperature of room temperature to 65 ° C. under a reduced pressure of 10 mmHg or less . For electrophotographic photoreceptor in which titanyl phthalocyanine having a maximum diffraction peak of Bragg angle 2θ of 27.2 ° ± 0.2 ° with respect to characteristic X-ray (wavelength 1.541Å) of at least Cu—Kα is dispersed in at least a solvent a dispersion, a wet containing the titanyl phthalocyanine contained in the dispersion is retrieved titanyl phthalocyanine from contact with at least an organic solvent as the last step of the titanyl phthalocyanine prepared, and the organic solvent was removed by filtration It is a titanyl phthalocyanine that is heat-dried at a temperature of room temperature to 65 ° C. under a reduced pressure of 10 mmHg or less in a state where the solid content of titanyl phthalocyanine in the cake is 48 wt% or more and 68 wt% or less. A dispersion for an electrophotographic photoreceptor. A photosensitive layer containing titanyl phthalocyanine having a maximum diffraction peak of Bragg angle 2θ of 27.2 ° ± 0.2 ° with respect to the characteristic X-ray of Cu—Kα (wavelength 1.541 mm) is provided on the conductive support. and, titanyl phthalocyanine contained in the photosensitive layer is retrieved titanyl phthalocyanine from contact with at least an organic solvent as the last step of the titanyl phthalocyanine prepared, and titanyl phthalocyanine in a wet cake containing organic solvent taken out by filtration An electrophotographic photosensitive member characterized by being a titanyl phthalocyanine heated and dried at a temperature of room temperature to 65 ° C. under a reduced pressure of 10 mmHg or less in a state where the solid content concentration is 48% by weight or more and 68 % by weight or less. . 4. The electrophotographic photosensitive member according to claim 3 , wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer. The electrophotographic photosensitive member according to claim 4 , wherein the charge transport layer contains at least a polycarbonate having a triarylamine structure in the main chain and / or side chain. In an electrophotographic method in which at least charging, image exposure, development, transfer, cleaning, and charge removal are repeatedly performed on an electrophotographic photosensitive member, the electrophotographic photosensitive member is at least Bragg with respect to a characteristic X-ray (wavelength: 1.541 mm) of Cu-Kα. maximum diffraction peak of the angular 2θ is taken titanyl phthalocyanine from contact with at least an organic solvent as the last step of the titanyl phthalocyanine prepared in 27.2 ° ± 0.2 °, and containing an organic solvent taken out by filtration among the titanyl phthalocyanine solid concentration following 68 wt% or more 48 wt% state during wet cake, in the following reduced pressure 10 mmHg, is contained titanyl phthalocyanine which has been heated drying at a temperature of 65 ° C. above room temperature An electrophotographic method characterized in that a photosensitive layer is provided on a conductive support. Law. An electrophotographic apparatus comprising at least a charging unit, an image exposing unit, a developing unit, a transfer unit, a cleaning unit, a charge eliminating unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member has at least a characteristic X of Cu-Kα. Titanyl phthalocyanine is taken out from at least a state in contact with an organic solvent as a final step of preparation of titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° ± 0.2 ° with respect to a line (wavelength 1.541Å) , and Heat drying at a temperature of room temperature to 65 ° C. under a reduced pressure of 10 mmHg or less in a state where the solid content of titanyl phthalocyanine in the wet cake containing the organic solvent removed by filtration is 48 wt% to 68 wt%. A photosensitive layer containing the prepared titanyl phthalocyanine is provided on a conductive support. An electrophotographic apparatus characterized by the above. A process cartridge for an electrophotographic apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member has a maximum diffraction peak at a Bragg angle of 2θ with respect to at least Cu-Kα characteristic X-rays (wavelength: 1.541 mm). there at least from the contact state with the organic solvent taken out titanyl phthalocyanine, and titanyl phthalocyanine solid in wet cake containing organic solvent taken out by filtration as the final step of the titanyl phthalocyanine prepared in 27.2 ° ± 0.2 ° A conductive support comprising a photosensitive layer containing titanyl phthalocyanine that has been heated and dried at a temperature of room temperature to 65 ° C. under a reduced pressure of 10 mmHg or less in a state where the partial concentration is 48 wt% or more and 68 wt% or less. A process cartridge for an electrophotographic apparatus, which is provided above.

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