JP2004004482A - Method and apparatus for image formation, and organic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for image formation and an organic photoreceptor which can provide an electrophotographic image of high image quality by transferring and fixing a toner image formed on the organic photoreceptor on recording paper by using electronic RDH without causing image defect such as black spot and void which are liable to cause when a double-sided image is formed. <P>SOLUTION: In the image forming method which transfers and fixes the toner image formed on the organic photoreceptor on the recording paper by using the electronic RDH to form the double-sided image, a surface layer of the organic photoreceptor is a charge transfer layer containing a charge transfer substance as a stereoisomer mixture and a toner used to form the toner image is ≤16 % in variation coefficient of the shape coefficient of toner particles. <P>COPYRIGHT: (C)2004,JPO

Description

【００４５】
一般式（１）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５は各々水素原子、炭素原子数１〜４のアルキル基又はアルコキシ基である。Ａｒ^１は水素原子又は置換、無置換の芳香族基、Ａｒ^２は置換、無置換の芳香族基を示す。
【００４６】
【化２】

【００４７】
一般式（２）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４は各々水素原子、炭素原子数１〜４のアルキル基又はアルコキシ基である。Ａｒ^１は水素原子又は置換、無置換の芳香族基、Ａｒ^２は置換、無置換の芳香族基を示す。
【００４８】
【化３】

【００４９】
一般式（３）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４は各々水素原子、炭素原子数１〜４のアルキル基又はアルコキシ基である。Ａｒ^１は水素原子又は置換、無置換の芳香族基、Ａｒ^２は置換、無置換の芳香族基を示す。
【００５０】
【化４】

【００５１】
一般式（４）中、Ｒ^１、Ｒ^２、Ｒ^３は各々水素原子、炭素原子数１〜４のアルキル基又はアルコキシ基である。Ａｒ^１は水素原子又は置換、無置換の芳香族基、Ａｒ^２は置換、無置換の芳香族基を示す。
【００５２】
【化５】

【００５３】
一般式（５）中、Ｒ^１、Ｒ^２、Ｒ^３は各々水素原子、炭素原子数１〜４のアルキル基又はアルコキシ基である。Ａｒ^１は水素原子又は置換、無置換の芳香族基、Ａｒ^２は置換、無置換の芳香族基を示す。
【００５４】
【化６】

【００５５】
一般式（６）中、Ｒ^１、Ｒ^２は各々水素原子、炭素原子数１〜４のアルキル基又はアルコキシ基である。Ａｒ^１は水素原子又は置換、無置換の芳香族基、Ａｒ^２は置換、無置換の芳香族基を示す。
【００５６】
又、一般式（１）〜一般式（６）のＡｒ^１、Ａｒ^２の置換、無置換の芳香族基が下記一般式（７）であることをが好ましい。
【００５７】
【化７】

【００５８】
一般式（７）中、Ｒ^６〜Ｒ^１７は各々水素原子、炭素原子数１〜４のアルキル基、アルコキシ基、炭素原子数１〜４のハロゲン化アルキル基、ハロゲン原子又は炭素原子数１〜４のアルコキシ基である。
【００５９】
以下に、本発明の好ましいビス（アリールエテニルフェニル）アニリン系化合物の例を挙げるが、本発明は下記の化合物例に限定されない。又、これらの化合物はいずれも立体異性体構造を持つことができる。
【００６０】
【化８】

【００６１】
【化９】

【００６２】
【化１０】

【００６３】
【化１１】

【００６４】
【化１２】

【００６５】
【化１３】

【００６６】
【化１４】

【００６７】
【化１５】

【００６８】
【化１６】

【００６９】
【化１７】

【００７０】
【化１８】

【００７１】
一方、ビス又はトリブタジエン系化合物とは窒素原子を介して、ブタジエン構造２個又は３個を対称的に有する化合物を意味し、下記一般式（８）、一般式（９）で示される化合物が好ましい。
【００７２】
【化１９】

【００７３】
一般式（８）中、Ｒ_１，Ｒ_２，Ｒ_３，Ｒ_４，Ｒ_５，Ｒ_６はそれぞれ同一であっても異なっていてもよく、水素原子、アルキル基、アルコキシ基、アリールオキシ基、ハロゲン原子又は置換基を有していてもよいアリール基を示す。ｍ２及びｎ２は０又は１を示す。
【００７４】
【化２０】

【００７５】
一般式（９）中、Ｒ_７〜Ｒ_１３はそれぞれ同一であっても異なってもよく、水素原子、低級アルキル基、アルコキシ基、アリールオキシ基、ハロゲン原子又は置換していてもよいアリール基を示し、ｍ３及びｎ３は０又は１を示す。
【００７６】
以下に、立体異性体構造を有するビス又はトリブタジエン系化合物の電荷輸送物質の化合物例を挙げるが、本発明は下記の化合物例に限定されない。
【００７７】
【化２１】

【００７８】
【化２２】

【００７９】
【化２３】

【００８０】
【化２４】

【００８１】
【化２５】

【００８２】
【化２６】

【００８３】
【化２７】

【００８４】
次に、上記のような電荷輸送物質を用いた有機感光体の層構成について記載する。
【００８５】
本発明の有機感光体とは電子写真感光体の構成に必要不可欠な電荷発生機能及び電荷輸送機能の少なくとも一方の機能を有機化合物に持たせて構成された電子写真感光体を意味し、公知の有機電荷発生物質又は有機電荷輸送物質から構成された感光体、電荷発生機能と電荷輸送機能を高分子錯体で構成した感光体等公知の有機電子写真感光体を全て含有する。
【００８６】
以下に本発明に用いられる有機感光体の構成について記載する。
導電性支持体
感光体に用いられる導電性支持体としてはシート状、円筒状のどちらを用いても良いが、画像形成装置をコンパクトに設計するためには円筒状導電性支持体の方が好ましい。
【００８７】
円筒状導電性支持体とは回転することによりエンドレスに画像を形成できるに必要な円筒状の支持体を意味し、真直度で０．１ｍｍ以下、振れ０．１ｍｍ以下の範囲にある導電性の支持体が好ましい。この真直度及び振れの範囲を超えると、良好な画像形成が困難になる。
【００８８】
導電性の材料としてはアルミニウム、ニッケルなどの金属ドラム、又はアルミニウム、酸化錫、酸化インジュウムなどを蒸着したプラスチックドラム、又は導電性物質を塗布した紙・プラスチックドラムを使用することができる。導電性支持体としては常温で比抵抗１０^３Ωｃｍ以下が好ましい。
【００８９】
本発明で用いられる導電性支持体は、その表面に封孔処理されたアルマイト膜が形成されたものを用いても良い。アルマイト処理は、通常例えばクロム酸、硫酸、シュウ酸、リン酸、硼酸、スルファミン酸等の酸性浴中で行われるが、硫酸中での陽極酸化処理が最も好ましい結果を与える。硫酸中での陽極酸化処理の場合、硫酸濃度は１００〜２００ｇ／Ｌ、アルミニウムイオン濃度は１〜１０ｇ／Ｌ、液温は２０℃前後、印加電圧は約２０Ｖで行うのが好ましいが、これに限定されるものではない。又、陽極酸化被膜の平均膜厚は、通常２０μｍ以下、特に１０μｍ以下が好ましい。
【００９０】
中間層
本発明においては導電性支持体と感光層の間に、バリヤー機能を備えた中間層を設けることもできる。
【００９１】
本発明においては導電性支持体と前記感光層のとの接着性改良、或いは該支持体からの電荷注入を防止するために、該支持体と前記感光層の間に中間層（下引層も含む）を設けることもできる。該中間層の材料としては、ポリアミド樹脂、塩化ビニル樹脂、酢酸ビニル樹脂並びに、これらの樹脂の繰り返し単位のうちの２つ以上を含む共重合体樹脂が挙げられる。これら下引き樹脂の中で繰り返し使用に伴う残留電位増加を小さくできる樹脂としてはポリアミド樹脂が好ましい。又、これら樹脂を用いた中間層の膜厚は０．０１〜０．５μｍが好ましい。
【００９２】
又、本発明に好ましく用いられる中間層はシランカップリング剤、チタンカップリング剤等の有機金属化合物を熱硬化させた硬化性金属樹脂を用いた中間層が挙げられる。硬化性金属樹脂を用いた中間層の膜厚は、０．１〜２μｍが好ましい。
【００９３】
又、本発明に好ましく用いられる中間層は無機粒子をバインダー樹脂中に分散した中間層が挙げられる。無機粒子の平均粒径は０．０１〜１μｍが好ましい。特に、表面処理をしたＮ型半導性微粒子をバインダー中に分散した中間層が好ましい。例えばシリカ・アルミナ処理及びシラン化合物で表面処理した平均粒径が０．０１〜１μｍの酸化チタンをポリアミド樹脂中に分散した中間層が挙げられる。このような中間層の膜厚は、１〜２０μｍが好ましい。
【００９４】
Ｎ型半導性微粒子とは、導電性キャリアを電子とする性質をもつ微粒子を示す。すなわち、導電性キャリアを電子とする性質とは、該Ｎ型半導性微粒子を絶縁性バインダーに含有させることにより、基体からのホール注入を効率的にブロックし、また、感光層からの電子に対してはブロッキング性を示さない性質を有するものをいう。
【００９５】
ここで、本発明のＮ型半導性粒子の判別方法について説明する。
導電性支持体上に膜厚５μｍの中間層（中間層を構成するバインダー樹脂中に粒子を５０質量％分散させた分散液を用いて中間層を形成する）を形成する。該中間層に負極性に帯電させて、光減衰特性を評価する。又、正極性に帯電させて同様に光減衰特性を評価する。
【００９６】
Ｎ型半導性粒子とは、上記評価で、負極性に帯電させた時の光減衰が正極性に帯電させた時の光減衰よりも大きい場合に、中間層に分散された粒子をＮ型半導性粒子という。
【００９７】
前記Ｎ型半導性微粒子は、具体的には酸化チタン（ＴｉＯ_２）、酸化亜鉛（ＺｎＯ）、酸化スズ（ＳｎＯ_２）等の微粒子が挙げられるが、本発明では、特に酸化チタンが好ましく用いられる。
【００９８】
本発明に用いられるＮ型半導性微粒子の平均粒径は、数平均一次粒径において１０ｎｍ以上５００ｎｍ以下の範囲のものが好ましく、より好ましくは１０ｎｍ〜２００ｎｍ、特に好ましくは、１５ｎｍ〜５０ｎｍである。
【００９９】
数平均一次粒径の値が前記範囲内にあるＮ型半導性微粒子を用いた中間層は層内での分散を緻密なものとすることができ、十分な電位安定性、及び黒ポチ発生防止機能を有する。
【０１００】
前記Ｎ型半導性微粒子の数平均一次粒径は、例えば酸化チタンの場合、透過型電子顕微鏡観察によって１００００倍に拡大し、ランダムに１００個の粒子を一次粒子として観察し、画像解析によりフェレ径の数平均径として測定される。
【０１０１】
本発明に用いられるＮ型半導性微粒子の形状は、樹枝状、針状および粒状等の形状があり、このような形状のＮ型半導性微粒子は、例えば酸化チタン粒子では、結晶型としては、アナターゼ型、ルチル型及びアモルファス型等があるが、いずれの結晶型のものを用いてもよく、また２種以上の結晶型を混合して用いてもよい。その中でもルチル型のものが最も良い。
【０１０２】
本発明のＮ型半導性微粒子に行われる疎水化表面処理の１つは、複数回の表面処理を行い、かつ該複数回の表面処理の中で、最後の表面処理が反応性有機ケイ素化合物による表面処理を行うものである。また、該複数回の表面処理の中で、少なくとも１回の表面処理がアルミナ、シリカ、及びジルコニアから選ばれる少なくとも１種類以上の表面処理であり、最後に反応性有機ケイ素化合物の表面処理を行うことが好ましい。
【０１０３】
尚、アルミナ処理、シリカ処理、ジルコニア処理とはＮ型半導性微粒子表面にアルミナ、シリカ、或いはジルコニアを析出させる処理を云い、これらの表面に析出したアルミナ、シリカ、ジルコニアにはアルミナ、シリカ、ジルコニアの水和物も含まれる。又、反応性有機ケイ素化合物の表面処理とは、処理液に反応性有機ケイ素化合物を用いることを意味する。
【０１０４】
この様に、酸化チタン粒子の様なＮ型半導性微粒子の表面処理を少なくとも２回以上行うことにより、Ｎ型半導性微粒子表面が均一に表面被覆（処理）され、該表面処理されたＮ型半導性微粒子を中間層に用いると、中間層内における酸化チタン粒子等のＮ型半導性微粒子の分散性が良好で、かつ黒ポチ等の画像欠陥を発生させない良好な感光体を得ることができるのである。
【０１０５】
感光層
本発明の感光体の感光層構成は前記中間層上に電荷発生機能と電荷輸送機能を１つの層に持たせた単層構造の感光層構成でも良いが、より好ましくは感光層の機能を電荷発生層（ＣＧＬ）と電荷輸送層（ＣＴＬ）に分離した構成をとるのがよい。機能を分離した構成を取ることにより繰り返し使用に伴う残留電位増加を小さく制御でき、その他の電子写真特性を目的に合わせて制御しやすい。負帯電用の感光体では中間層の上に電荷発生層（ＣＧＬ）、その上に電荷輸送層（ＣＴＬ）の構成を取ることが好ましい。正帯電用の感光体では前記層構成の順が負帯電用感光体の場合の逆となる。本発明の最も好ましい感光層構成は前記機能分離構造を有する負帯電感光体構成である。
【０１０６】
以下に機能分離負帯電感光体の感光層構成について説明する。
電荷発生層
電荷発生層には電荷発生物質（ＣＧＭ）を含有する。その他の物質としては必要によりバインダー樹脂、その他添加剤を含有しても良い。
【０１０７】
電荷発生物質（ＣＧＭ）としては公知の電荷発生物質（ＣＧＭ）を用いることができる。例えばフタロシアニン顔料、アゾ顔料、ペリレン顔料、アズレニウム顔料などを用いることができる。これらの中で繰り返し使用に伴う残留電位増加を最も小さくできるＣＧＭは複数の分子間で安定な凝集構造をとりうる立体、電位構造を有するものであり、具体的には特定の結晶構造を有するフタロシアニン顔料、ペリレン顔料のＣＧＭが挙げられる。例えばＣｕ−Ｋα線に対するブラッグ角２θが２７．２°に最大ピークを有するチタニルフタロシアニン、同２θが１２．４に最大ピークを有するベンズイミダゾールペリレン等のＣＧＭは繰り返し使用に伴う劣化がほとんどなく、残留電位増加小さくすることができる。
【０１０８】
電荷発生層にＣＧＭの分散媒としてバインダーを用いる場合、バインダーとしては公知の樹脂を用いることができるが、最も好ましい樹脂としてはホルマール樹脂、ブチラール樹脂、シリコーン樹脂、シリコーン変性ブチラール樹脂、フェノキシ樹脂等が挙げられる。バインダー樹脂と電荷発生物質との割合は、バインダー樹脂１００質量部に対し２０〜６００質量部が好ましい。これらの樹脂を用いることにより、繰り返し使用に伴う残留電位増加を最も小さくできる。電荷発生層の膜厚は０．０１μｍ〜２μｍが好ましい。
【０１０９】
電荷輸送層
本発明で電荷輸送層とは、電荷発生物質等で発生した電荷キャリア（電子又はホール）を輸送する機能を有する層を意味する。
【０１１０】
本発明の表面層は、電荷輸送層の機能を有し、且つ電荷輸送物質（ＣＴＭ）として立体異性体混合物を用い、ＣＴＭを分散し製膜するバインダー樹脂を含有する。その他の物質としては必要により酸化防止剤等の添加剤を含有しても良い。
【０１１１】
電荷輸送物質（ＣＴＭ）としては前記した立体異性体混合物の電荷輸送物質の他に公知の電荷輸送物質を併用して用いることもできる。例えばトリフェニルアミン誘導体、ヒドラゾン化合物、スチリル化合物、ベンジジン化合物、ブタジエン化合物などを併用して、用いることができる。これら電荷輸送物質は通常、適当なバインダー樹脂中に溶解して層形成が行われる。
【０１１２】
電荷輸送層（ＣＴＬ）に用いられる樹脂としては、例えばポリスチレン、アクリル樹脂、メタクリル樹脂、塩化ビニル樹脂、酢酸ビニル樹脂、ポリビニルブチラール樹脂、エポキシ樹脂、ポリウレタン樹脂、フェノール樹脂、ポリエステル樹脂、アルキッド樹脂、ポリカーボネート樹脂、シリコーン樹脂、メラミン樹脂並びに、これらの樹脂の繰り返し単位のうちの２つ以上を含む共重合体樹脂。又これらの絶縁性樹脂の他、ポリ−Ｎ−ビニルカルバゾール等の高分子有機半導体が挙げられる。
【０１１３】
これらＣＴＬのバインダーとして最も好ましいものはポリカーボネート樹脂である。ポリカーボネート樹脂はＣＴＭの分散性、電子写真特性を良好にすることにおいて、最も好ましい。又電荷輸送層が表面層となる感光体の場合は、機械的摩耗に強いポリカーボネートが好ましく、このようなポリカーボネートとしては平均分子量が４０，０００〜２５，０００のポリカーボネートが好ましい。ここで平均分子量は数平均分子量、重量平均分子量、及び粘度平均分子量のいずれのものでもよい。バインダー樹脂と電荷輸送物質との割合は、バインダー樹脂１００質量部に対し１０〜２００質量部が好ましい。又、電荷輸送層の膜厚は１０〜４０μｍが好ましい。
【０１１４】
又、電荷輸送層には酸化防止剤を含有させることが好ましい。該酸化防止剤とは、その代表的なものは有機感光体中ないしは有機感光体表面に存在する自動酸化性物質に対して、光、熱、放電等の条件下で酸素の作用を防止ないし、抑制する性質を有する物質である。代表的には下記の化合物群が挙げられる。
【０１１５】
【化２８】

【０１１６】
【化２９】

【０１１７】
【化３０】

【０１１８】
【化３１】

【０１１９】
電荷輸送層は２層以上の層構成にしてもよい。この場合は表面の電荷輸送層が本発明の構成を満たせばよい。
【０１２０】
中間層、感光層、保護層等の層形成に用いられる溶媒又は分散媒としては、ｎ−ブチルアミン、ジエチルアミン、エチレンジアミン、イソプロパノールアミン、トリエタノールアミン、トリエチレンジアミン、Ｎ，Ｎ−ジメチルホルムアミド、アセトン、メチルエチルケトン、メチルイソプロピルケトン、シクロヘキサノン、ベンゼン、トルエン、キシレン、クロロホルム、ジクロロメタン、１，２−ジクロロエタン、１，２−ジクロロプロパン、１，１，２−トリクロロエタン、１，１，１−トリクロロエタン、トリクロロエチレン、テトラクロロエタン、テトラヒドロフラン、ジオキソラン、ジオキサン、メタノール、エタノール、ブタノール、イソプロパノール、酢酸エチル、酢酸ブチル、ジメチルスルホキシド、メチルセロソルブ等が挙げられる。本発明はこれらに限定されるものではないが、ジクロロメタン、１，２−ジクロロエタン、メチルエチルケトン等が好ましく用いられる。また、これらの溶媒は単独或いは２種以上の混合溶媒として用いることもできる。
【０１２１】
本発明の電子写真感光体を製造するための塗布加工方法としては、浸漬塗布、スプレー塗布、円形量規制型塗布等の塗布加工法が用いられるが、感光層の上層側の塗布加工は下層の膜を極力溶解させないため、又、均一塗布加工を達成するためスプレー塗布又は円形量規制型（円形スライドホッパ型がその代表例）塗布等の塗布加工方法を用いるのが好ましい。なお前記スプレー塗布については例えば特開平３−９０２５０号及び特開平３−２６９２３８号公報に詳細に記載され、前記円形量規制型塗布については例えば特開昭５８−１８９０６１号公報に詳細に記載されている。
【０１２２】
次に、本発明のトナー像の形成の為に用いられるトナーについて説明する。
本発明のトナー像の形成の為に用いられるトナーは、
▲１▼トナー粒子の形状係数の変動係数が１６％以下、
▲２▼トナー粒子の形状係数が１．２〜１．６の範囲にあるトナー粒子の割合が６５個数％以上、
▲３▼角がないトナー粒子の割合が５０個数％以上、
▲４▼トナー粒子の個数粒度分布における個数変動係数が２７％以下、
▲５▼トナー粒子の粒径をＤ（μｍ）とするとき、自然対数ｌｎＤを横軸にとり、この横軸を０．２３間隔で複数の階級に分けた個数基準の粒度分布を示すヒストグラムにおける最頻階級に含まれるトナー粒子の相対度数（ｍ_１）と、前記最頻階級の次に頻度の高い階級に含まれるトナー粒子の相対度数（ｍ_２）との和（Ｍ）が７０％以上である。
【０１２３】
即ち、本発明では、前記表面層を有する感光体に上記▲１▼〜▲５▼の少なくとも１つ以上の条件を満たしたトナーを含有した現像剤を用いることにより、反転現像における白ヌケや黒ポチ等の画像欠陥の発生を防止し、クリーニング性を向上させ、良好な電子写真画像を得ることができる。上記▲１▼〜▲５▼の条件の中でも、▲２▼及び▲５▼の条件が他の▲１▼、▲３▼、▲４▼の条件に比し、本発明の目的をより良く達成する上で、重要である。しかしながら、他の▲１▼、▲３▼、▲４▼の条件も本発明の目的達成に効果を発揮する特性である。特に上記▲１▼〜▲５▼の全ての条件を満たしたトナーと前記表面層を有する感光体、即ち、立体異性体混合物の電荷輸送物質を含有する電荷輸送層を表面層として有する感光体と併用することにより、白ヌケと黒ポチの相反する画像欠陥を顕著に改善することができる。
【０１２４】
以下、上記▲１▼〜▲５▼のトナーについて説明する。
トナーの形状係数（＝トナー粒子の形状係数）
トナー粒子の形状係数は、下記式により示されるものであり、トナー粒子の丸さの度合いを示す。
【０１２５】
形状係数＝（（最大径／２）^２×π）／投影面積
ここに、最大径とは、トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。また、投影面積とは、トナー粒子の平面上への投影像の面積をいう。
【０１２６】
本発明では、この形状係数は、走査型電子顕微鏡により２０００倍にトナー粒子を拡大した写真を撮影し、ついでこの写真に基づいて「ＳＣＡＮＮＩＮＧ　ＩＭＡＧＥ　ＡＮＡＬＹＺＥＲ」（日本電子社製）を使用して写真画像の解析を行うことにより測定した。この際、１００個のトナー粒子を使用して本発明の形状係数を上記算出式にて測定したものである。
【０１２７】
本発明のトナーは、この形状係数が１．２〜１．６の範囲にあるトナー粒子の割合を６５個数％以上であり、好ましくは、７０個数％以上である。
【０１２８】
本発明では前記立体異性体混合物の電荷輸送物質を含有する表面層を有する有機感光体上に形成された潜像をこの形状係数が１．２〜１．６の範囲にあるトナー粒子の割合を６５個数％以上含有する現像剤により現像することにより、白ヌケや黒ポチ等の画像欠陥の発生を防止し、クリーニング性が向上し、鮮鋭性の良好な電子写真画像が得られる。
【０１２９】
この形状係数を制御する方法は特に限定されるものではない。例えば、トナー粒子を熱気流中に噴霧する方法、トナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、トナーを溶解しない溶媒中に添加し旋回流を付与する方法等により、形状係数を１．２〜１．６にしたトナー粒子を調製し、これを通常のトナー中へ本発明の範囲内になるように添加して調整する方法がある。また、いわゆる重合法トナーを調製する段階で全体の形状を制御し、形状係数を１．２〜１．６に調整したトナー粒子を同様に通常のトナーへ添加して調整する方法がある。
【０１３０】
上記方法の中では重合法トナーが製造方法として簡便である点と、粉砕トナーに比較して表面の均一性に優れる点等で好ましい。該重合法トナー（重合トナーとも云う）とはトナー用バインダーの樹脂の生成とトナー形状がバインダー樹脂の原料モノマーの重合と、必要により、その後の化学的処理により形成されるトナーを意味する。より具体的には懸濁重合、乳化重合等の重合反応と、必要により、その後に行われる粒子同士の融着工程を経て得られるトナーを意味する。
【０１３１】
重合トナーは原料モノマーを水系で均一に分散した後に重合させトナーを製造することから、トナーの粒度分布、及び形状が均一なトナーが得られる。
【０１３２】
トナーの形状係数の変動係数（＝トナー粒子の形状係数の変動係数）
本発明のトナー粒子の「形状係数の変動係数」は下記式から算出される。
【０１３３】
変動係数＝〔Ｓ／Ｋ〕×１００（％）
〔式中、Ｓ_１は１００個のトナー粒子の形状係数の標準偏差を示し、Ｋは形状係数の平均値を示す。〕
本発明のトナーは、この形状係数の変動係数が１６％以下であり、好ましくは１４％以下である。
【０１３４】
本発明では前記立体異性体混合物の電荷輸送物質を含有する表面層を有する有機感光体上に形成された潜像をこの形状係数の変動係数が１６％以下であるトナーを用いた現像剤により現像することにより、白ヌケや黒ポチ等の画像欠陥の発生を防止し、クリーニング性が向上し、鮮鋭性の良好な電子写真画像が得られる。
【０１３５】
このトナーの形状係数および形状係数の変動係数を、極めてロットのバラツキなく均一に制御するために、本発明のトナーを構成する樹脂粒子（重合体粒子）を調製（重合）、当該樹脂粒子を融着、形状制御させる工程において、形成されつつあるトナー粒子（着色粒子）の特性をモニタリングしながら適正な工程終了時期を決めてもよい。
【０１３６】
モニタリングするとは、インラインに測定装置を組み込みその測定結果に基づいて、工程条件の制御をするという意味である。すなわち、形状などの測定をインラインに組み込んで、例えば樹脂粒子を水系媒体中で会合あるいは融着させることで形成する重合法トナーでは、融着などの工程で逐次サンプリングを実施しながら形状や粒径を測定し、所望の形状になった時点で反応を停止する。
【０１３７】
モニタリング方法としては、特に限定されるものではないが、フロー式粒子像分析装置ＦＰＩＡ−２０００（東亜医用電子社製）を使用することができる。本装置は試料液を通過させつつリアルタイムで画像処理を行うことで形状をモニタリングできるため好適である。すなわち、反応場よりポンプなどを使用し、常時モニターし、形状などを測定することを行い、所望の形状などになった時点で反応を停止するものである。
【０１３８】
トナーの個数変動係数（＝トナー粒子の個数変動係数）
本発明のトナー粒子の個数粒度分布および個数変動係数はコールターカウンターＴＡ−あるいはコールターマルチサイザー（コールター社製）で測定されるものである。本発明においてはコールターマルチサイザーを用い、粒度分布を出力するインターフェース（日科機製）、パーソナルコンピューターを接続して使用した。前記コールターマルチサイザーにおいて使用するアパーチャーとしては１００μｍのものを用いて、２μｍ以上のトナーの体積、個数を測定して粒度分布および平均粒径を算出した。個数粒度分布とは、粒子径に対するトナー粒子の相対度数を表すものであり、個数平均粒径とは、個数粒度分布におけるメジアン径を表すものである。トナー粒子の「個数粒度分布における個数変動係数」は下記式から算出される。
【０１３９】
個数変動係数＝〔Ｓ／Ｄｎ〕×１００（％）
〔式中、Ｓ_２は個数粒度分布における標準偏差を示し、Ｄ_ｎは個数平均粒径（μｍ）を示す。〕
本発明のトナー粒子の個数変動係数は２７％以下であり、好ましくは２５％以下である。
【０１４０】
本発明では前記立体異性体混合物の電荷輸送物質を含有する表面層を有する有機感光体上に形成された潜像をトナー粒子の個数変動係数は２７％以下であるトナーを用いた現像剤により現像することにより、白ヌケや黒ポチ等の画像欠陥の発生を防止し、クリーニング性が向上し、鮮鋭性の良好な電子写真画像が得られる。
【０１４１】
本発明のトナーにおける個数変動係数を制御する方法は特に限定されるものではない。例えば、トナー粒子を風力により分級する方法も使用できるが、個数変動係数をより小さくするためには液中での分級が効果的である。この液中で分級する方法としては、遠心分離機を用い、回転数を制御してトナー粒子径の違いにより生じる沈降速度差に応じてトナー粒子を分別回収し調製する方法がある。
【０１４２】
特に懸濁重合法によりトナーを製造する場合、個数粒度分布における個数変動係数を２７％以下とするためには分級操作が必須である。懸濁重合法では、重合前に重合性単量体を水系媒体中にトナーとしての所望の大きさの油滴に分散させることが必要である。すなわち、重合性単量体の大きな油滴に対して、ホモミキサーやホモジナイザーなどによる機械的な剪断を繰り返して、トナー粒子程度の大きさまで油滴を小さくすることとなるが、このような機械的な剪断による方法では、得られる油滴の個数粒度分布は広いものとなり、従って、これを重合してなるトナーの粒度分布も広いものとなる。このために分級操作が必須となる。
【０１４３】
角がないトナー粒子の割合
本発明のトナーを構成するトナー粒子中、角がないトナー粒子の割合は５０個数％以上であることが必要とされ、この割合が７０個数％以上であることが好ましい。
【０１４４】
本発明のトナーを構成するトナー粒子中、角がないトナー粒子の割合は５０個数％以上であることが好ましく、更に好ましくは７０個数％以上とされる。
【０１４５】
本発明では前記立体異性体混合物の電荷輸送物質を含有する表面層を有する有機感光体上に形成された潜像を角がないトナー粒子の割合は５０個数％以上であるトナーを用いた現像剤により現像することにより、白ヌケや黒ポチ等の画像欠陥の発生を防止し、クリーニング性が向上し、鮮鋭性の良好な電子写真画像が得られる。
【０１４６】
ここに、「角がないトナー粒子」とは、電荷の集中するような突部またはストレスにより摩耗しやすいような突部を実質的に有しないトナー粒子を言い、具体的には以下のトナー粒子を角がないトナー粒子という。すなわち、図２（ａ）に示すように、トナー粒子Ｔの長径をＬとするときに、半径（Ｌ／１０）の円Ｃで、トナー粒子Ｔの周囲線に対し１点で内側に接しつつ内側をころがした場合に、当該円ＣがトナーＴの外側に実質的にはみださない場合を「角がないトナー粒子」という。「実質的にはみ出さない場合」とは、はみ出す円が存在する突起が１箇所以下である場合をいう。また、「トナー粒子の長径」とは、当該トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。なお、図２（ｂ）および（ｃ）は、それぞれ角のあるトナー粒子の投影像を示している。
【０１４７】
角がないトナー粒子の割合の測定は次のようにして行った。先ず、走査型電子顕微鏡によりトナー粒子を拡大した写真を撮影し、さらに拡大して１５，０００倍の写真像を得る。次いでこの写真像について前記の角の有無を測定する。この測定を１００個のトナー粒子について行った。
【０１４８】
角がないトナーを得る方法は特に限定されるものではない。例えば、形状係数を制御する方法として前述したように、トナー粒子を熱気流中に噴霧する方法、またはトナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、あるいはトナーを溶解しない溶媒中に添加し、旋回流を付与することによって得ることができる。
【０１４９】
また、樹脂粒子を会合あるいは融着させることで形成する重合法トナーにおいては、融着停止段階では融着粒子表面には多くの凹凸があり、表面は平滑でないが、形状制御工程での温度、攪拌翼の回転数および攪拌時間等の条件を適当なものとすることによって、角がないトナーが得られる。これらの条件は、樹脂粒子の物性により変わるものであるが、例えば、樹脂粒子のガラス転移点温度以上で、より高回転数とすることにより、表面は滑らかとなり、角がないトナーが形成できる。
【０１５０】
トナー粒子の粒径
本発明のトナーの粒径は、個数平均粒径で３．０〜８．５μｍのものが好ましい。この粒径は、重合法によりトナー粒子を形成させる場合には、後に詳述するトナーの製造方法において、凝集剤の濃度や有機溶媒の添加量、または融着時間、さらには重合体自体の組成によって制御することができる。
【０１５１】
個数平均粒径が３．０〜８．５μｍであることにより、転写効率が高くなってハーフトーンの画質が向上し、細線やドット等の画質が向上する。
【０１５２】
本発明のトナーは、トナー粒子の粒径をＤ（μｍ）とするとき、自然対数ｌｎＤを横軸にとり、この横軸を０．２３間隔で複数の階級に分けた個数基準の粒度分布を示すヒストグラムにおいて、最頻階級に含まれるトナー粒子の相対度数（ｍ_１）と、前記最頻階級の次に頻度の高い階級に含まれるトナー粒子の相対度数（ｍ_２）との和（Ｍ）が７０％以上であるトナーである。
【０１５３】
本発明では前記立体異性体混合物の電荷輸送物質を含有する表面層を有する有機感光体上に形成された潜像を相対度数（ｍ_１）と相対度数（ｍ_２）との和（Ｍ）が７０％以上であるトナーを用いた現像剤により現像することにより、白ヌケや黒ポチ等の画像欠陥の発生を防止し、クリーニング性が向上し、鮮鋭性の良好な電子写真画像が得られる。
【０１５４】
本発明において、前記の個数基準の粒度分布を示すヒストグラムは、自然対数ｌｎＤ（Ｄ：個々のトナー粒子の粒径）を０．２３間隔で複数の階級（０〜０．２３：０．２３〜０．４６：０．４６〜０．６９：０．６９〜０．９２：０．９２〜１．１５：１．１５〜１．３８：１．３８〜１．６１：１．６１〜１．８４：１．８４〜２．０７：２．０７〜２．３０：２．３０〜２．５３：２．５３〜２．７６・・・）に分けた個数基準の粒度分布を示すヒストグラムであり、このヒストグラムは、下記の条件に従って、コールターマルチサイザーにより測定されたサンプルの粒径データを、Ｉ／Ｏユニットを介してコンピュータに転送し、当該コンピュータにおいて、粒度分布分析プログラムにより作製されたものである。
〔測定条件〕
（１）アパーチャー：１００μｍ
（２）サンプル調製法：電解液〔ＩＳＯＴＯＮ　Ｒ−１１（コールターサイエンティフィックジャパン社製）〕５０〜１００ｍｌに界面活性剤（中性洗剤）を適量加えて攪拌し、これに測定試料１０〜２０ｍｇを加える。この系を超音波分散機にて１分間分散処理することにより調製する。
【０１５５】
トナーの製造方法
本発明のトナーは、少なくとも重合性単量体を水系媒体中で重合せしめて得られる重合トナーであることが好ましく、また、少なくとも樹脂粒子を水系媒体中で会合させて得られる重合トナーであることが好ましい。以下、本発明の重合トナー（以後、単にトナーとも云う）を製造する方法について詳細に説明する。
【０１５６】
本発明の重合トナーは、懸濁重合法や、必要な添加剤の乳化液を加えた液中（水系媒体中）にて単量体を乳化重合して微粒の重合体粒子（樹脂粒子）を調製し、その後に、有機溶媒、凝集剤等を添加して当該樹脂粒子を会合する方法で製造することができる。ここで「会合」とは、前記樹脂粒子が複数個融着することをいい、当該樹脂粒子と他の粒子（例えば着色剤粒子）とが融着する場合も含むものとする。
【０１５７】
尚、本発明で重合トナーとは、トナー用バインダーの樹脂の生成とトナー形状がバインダー樹脂の原料モノマーの重合と、必要によりその後の化学的処理により形成されるトナーを意味する。より具体的には懸濁重合、乳化重合等の重合反応と、必要によりその後に行われる粒子同士の融着工程を経て形成されるトナーを意味する。
【０１５８】
本発明の重合トナーを製造する方法の一例を示せば、重合性単量体中に着色剤や必要に応じて離型剤、荷電制御剤、さらに重合開始剤等の各種構成材料を添加し、ホモジナイザー、サンドミル、サンドグラインダー、超音波分散機などで重合性単量体に各種構成材料を溶解あるいは分散させる。この各種構成材料が溶解あるいは分散された重合性単量体を分散安定剤を含有した水系媒体中にホモミキサーやホモジナイザーなどを使用しトナーとしての所望の大きさの油滴に分散させる。その後、攪拌機構が後述の攪拌翼である反応装置（攪拌装置）へ移し、加熱することで重合反応を進行させる。反応終了後、分散安定剤を除去し、濾過、洗浄し、さらに乾燥することで本発明のトナーを調製する。
【０１５９】
なお、本発明でいうところの「水系媒体」とは、少なくとも水が５０質量％以上含有されたものを示す。
【０１６０】
また、本発明の重合トナーを製造する方法として樹脂粒子を水系媒体中で会合あるいは融着させて調製する方法も挙げることができる。この方法としては、特に限定されるものではないが、例えば、特開平５−２６５２５２号公報や特開平６−３２９９４７号公報、特開平９−１５９０４号公報に示す方法を挙げることができる。すなわち、樹脂粒子と着色剤などの構成材料の分散粒子、あるいは樹脂および着色剤等より構成される微粒子を複数以上会合させる方法、特に水中にてこれらを乳化剤を用いて分散した後に、臨界凝集濃度以上の凝集剤を加え塩析させると同時に、形成された重合体自体のガラス転移点温度以上で加熱融着させて融着粒子を形成しつつ徐々に粒径を成長させ、目的の粒径となったところで水を多量に加えて粒径成長を停止し、さらに加熱、攪拌しながら粒子表面を平滑にして形状を制御し、その粒子を含水状態のまま流動状態で加熱乾燥することにより、本発明のトナーを形成することができる。なお、ここにおいて凝集剤と同時に水に対して無限溶解する溶媒を加えてもよい。
【０１６１】
樹脂を構成する重合性単量体として使用されるものは、スチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、α−メチルスチレン、ｐ−クロロスチレン、３，４−ジクロロスチレン、ｐ−フェニルスチレン、ｐ−エチルスチレン、２，４−ジメチルスチレン、ｐ−ｔｅｒｔ−ブチルスチレン、ｐ−ｎ−ヘキシルスチレン、ｐ−ｎ−オクチルスチレン、ｐ−ｎ−ノニルスチレン、ｐ−ｎ−デシルスチレン、ｐ−ｎ−ドデシルスチレンの様なスチレンあるいはスチレン誘導体、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ｎ−ブチル、メタクリル酸イソプロピル、メタクリル酸イソブチル、メタクリル酸ｔ−ブチル、メタクリル酸ｎ−オクチル、メタクリル酸２−エチルヘキシル、メタクリル酸ステアリル、メタクリル酸ラウリル、メタクリル酸フェニル、メタクリル酸ジエチルアミノエチル、メタクリル酸ジメチルアミノエチル等のメタクリル酸エステル誘導体、アクリル酸メチル、アクリル酸エチル、アクリル酸イソプロピル、アクリル酸ｎ−ブチル、アクリル酸ｔ−ブチル、アクリル酸イソブチル、アクリル酸ｎ−オクチル、アクリル酸２−エチルヘキシル、アクリル酸ステアリル、アクリル酸ラウリル、アクリル酸フェニル等の、アクリル酸エステル誘導体、エチレン、プロピレン、イソブチレン等のオレフィン類、塩化ビニル、塩化ビニリデン、臭化ビニル、フッ化ビニル、フッ化ビニリデン等のハロゲン系ビニル類、プロピオン酸ビニル、酢酸ビニル、ベンゾエ酸ビニル等のビニルエステル類、ビニルメチルエーテル、ビニルエチルエーテル等のビニルエーテル類、ビニルメチルケトン、ビニルエチルケトン、ビニルヘキシルケトン等のビニルケトン類、Ｎ−ビニルカルバゾール、Ｎ−ビニルインドール、Ｎ−ビニルピロリドン等のＮ−ビニル化合物、ビニルナフタレン、ビニルピリジン等のビニル化合物類、アクリロニトリル、メタクリロニトリル、アクリルアミド等のアクリル酸あるいはメタクリル酸誘導体がある。これらビニル系単量体は単独あるいは組み合わせて使用することができる。
【０１６２】
また、樹脂を構成する重合性単量体としてイオン性解離基を有するものを組み合わせて用いることがさらに好ましい。例えば、カルボキシル基、スルフォン酸基、リン酸基等の置換基を単量体の構成基として有するもので、具体的には、アクリル酸、メタクリル酸、マレイン酸、イタコン酸、ケイ皮酸、フマール酸、マレイン酸モノアルキルエステル、イタコン酸モノアルキルエステル、スチレンスルフォン酸、アリルスルフォコハク酸、２−アクリルアミド−２−メチルプロパンスルフォン酸、アシッドホスホオキシエチルメタクリレート、３−クロロ−２−アシッドホスホオキシプロピルメタクリレート等が挙げられる。
【０１６３】
さらに、ジビニルベンゼン、エチレングリコールジメタクリレート、エチレングリコールジアクリレート、ジエチレングリコールジメタクリレート、ジエチレングリコールジアクリレート、トリエチレングリコールジメタクリレート、トリエチレングリコールジアクリレート、ネオペンチルグリコールジメタクリレート、ネオペンチルグリコールジアクリレート等の多官能性ビニル類を使用して架橋構造の樹脂とすることもできる。
【０１６４】
これら重合性単量体はラジカル重合開始剤を用いて重合することができる。この場合、懸濁重合法では油溶性重合開始剤を用いることができる。この油溶性重合開始剤としては、２，２′−アゾビス−（２，４−ジメチルバレロニトリル）、２，２′−アゾビスイソブチロニトリル、１，１′−アゾビス（シクロヘキサン−１−カルボニトリル）、２，２′−アゾビス−４−メトキシ−２，４−ジメチルバレロニトリル、アゾビスイソブチロニトリル等のアゾ系またはジアゾ系重合開始剤、ベンゾイルパーオキサイド、メチルエチルケトンペルオキサイド、ジイソプロピルペルオキシカーボネート、クメンヒドロペルオキサイド、ｔ−ブチルヒドロペルオキサイド、ジ−ｔ−ブチルペルオキサイド、ジクミルペルオキサイド、２，４−ジクロロベンゾイルペルオキサイド、ラウロイルペルオキサイド、２，２−ビス−（４，４−ｔ−ブチルペルオキシシクロヘキシル）プロパン、トリス−（ｔ−ブチルペルオキシ）トリアジンなどの過酸化物系重合開始剤や過酸化物を側鎖に有する高分子開始剤などを挙げることができる。
【０１６５】
また、乳化重合法を用いる場合には水溶性ラジカル重合開始剤を使用することができる。水溶性重合開始剤としては、過硫酸カリウム、過硫酸アンモニウム等の過硫酸塩、アゾビスアミノジプロパン酢酸塩、アゾビスシアノ吉草酸およびその塩、過酸化水素等を挙げることができる。
【０１６６】
分散安定剤としては、リン酸三カルシウム、リン酸マグネシウム、リン酸亜鉛、リン酸アルミニウム、炭酸カルシウム、炭酸マグネシウム、水酸化カルシウム、水酸化マグネシウム、水酸化アルミニウム、メタケイ酸カルシウム、硫酸カルシウム、硫酸バリウム、ベントナイト、シリカ、アルミナ等を挙げることができる。さらに、ポリビニルアルコール、ゼラチン、メチルセルロース、ドデシルベンゼンスルフォン酸ナトリウム、エチレンオキサイド付加物、高級アルコール硫酸ナトリウム等の界面活性剤として一般的に使用されているものを分散安定剤として使用することができる。
【０１６７】
本発明において優れた樹脂としては、ガラス転移点が２０〜９０℃のものが好ましく、軟化点が８０〜２２０℃のものが好ましい。ガラス転移点は示差熱量分析方法で測定されるものであり、軟化点は高化式フローテスターで測定することができる。さらに、これら樹脂としてはゲルパーミエーションクロマトグラフィーにより測定される分子量が数平均分子量（Ｍｎ）で１０００〜１０００００、重量平均分子量（Ｍｗ）で２０００〜１００００００のものが好ましい。さらに、分子量分布として、Ｍｗ／Ｍｎが１．５〜１００、特に１．８〜７０のものが好ましい。
【０１６８】
前記樹脂粒子を水系媒体中で会合させる際に使用される凝集剤としては特に限定されるものではないが、金属塩から選択されるものが好適に使用される。具体的には、一価の金属として例えばナトリウム、カリウム、リチウム等のアルカリ金属の塩、二価の金属として例えばカルシウム、マグネシウム等のアルカリ土類の金属塩、マンガン、銅等の二価の金属の塩、鉄、アルミニウム等の三価の金属の塩等が挙げられ、具体的な塩としては、塩化ナトリウム、塩化カリウム、塩化リチウム、塩化カルシウム、塩化亜鉛、硫酸銅、硫酸マグネシウム、硫酸マンガン等を挙げることができる。これらは組み合わせて使用してもよい。
【０１６９】
これらの凝集剤は臨界凝集濃度以上添加することが好ましい。この臨界凝集濃度とは、水性分散物の安定性に関する指標であり、凝集剤を添加して凝集が発生する濃度を示すものである。この臨界凝集濃度は、乳化された成分および分散剤自体によって大きく変化するものである。例えば、岡村誠三他著「高分子化学　１７、６０１（１９６０）日本高分子学会編」等に記述されており、詳細な臨界凝集濃度を求めることができる。また、別な手法として、目的とする粒子分散液に所望の塩を濃度を変えて添加し、その分散液のζ（ゼータ）電位を測定し、この値が変化する塩濃度を臨界凝集濃度として求めることもできる。
【０１７０】
本発明の凝集剤の添加量は、臨界凝集濃度以上であればよいが、好ましくは臨界凝集濃度の１．２倍以上、さらに好ましくは、１．５倍以上添加することがよい。
【０１７１】
凝集剤と共に使用される「水に対して無限溶解する溶媒」としては、形成される樹脂を溶解させないものが選択される。具体的には、メタノール、エタノール、プロパノール、イソプロパノール、ｔ−ブタノール、メトキシエタノール、ブトキシエタノール等のアルコール類、アセトニトリル等のニトリル類、ジオキサン等のエーテル類を挙げることができる。特に、エタノール、プロパノール、イソプロパノールが好ましい。
【０１７２】
この水に対して無限溶解する溶媒の添加量は、凝集剤を添加した重合体含有分散液に対して１〜１００体積％が好ましい。
【０１７３】
なお、粒子形状を均一化させるためには、着色粒子を調製し、濾過した後に粒子に対して１０質量％以上の水が存在したスラリーを流動乾燥させることが好ましいが、この際、特に重合体中に極性基を有するものが好ましい。この理由としては、極性基が存在している重合体に対して、存在している水が多少膨潤する効果を発揮するために、形状の均一化が特に図られやすいからであると考えられる。
【０１７４】
本発明のトナーは少なくとも樹脂と着色剤を含有するものであるが、必要に応じて定着性改良剤である離型剤や荷電制御剤等を含有することもできる。さらに、上記樹脂と着色剤を主成分とするトナー粒子に対して無機微粒子や有機微粒子等で構成される外添剤を添加したものであってもよい。
【０１７５】
本発明のトナーに使用する着色剤としてはカーボンブラック、磁性体、染料、顔料等を任意に使用することができ、カーボンブラックとしてはチャンネルブラック、ファーネスブラック、アセチレンブラック、サーマルブラック、ランプブラック等が使用される。磁性体としては鉄、ニッケル、コバルト等の強磁性金属、これらの金属を含む合金、フェライト、マグネタイト等の強磁性金属の化合物、強磁性金属を含まないが熱処理する事により強磁性を示す合金、例えばマンガン−銅−アルミニウム、マンガン−銅−錫等のホイスラー合金と呼ばれる種類の合金、二酸化クロム等を用いる事ができる。
【０１７６】
染料としてはＣ．Ｉ．ソルベントレッド１、同４９、同５２、同５８、同６３、同１１１、同１２２、Ｃ．Ｉ．ソルベントイエロー１９、同４４、同７７、同７９、同８１、同８２、同９３、同９８、同１０３、同１０４、同１１２、同１６２、Ｃ．Ｉ．ソルベントブルー２５、同３６、同６０、同７０、同９３、同９５等を用いる事ができ、またこれらの混合物も用いる事ができる。顔料としてはＣ．Ｉ．ピグメントレッド５、同４８：１、同５３：１、同５７：１、同１２２、同１３９、同１４４、同１４９、同１６６、同１７７、同１７８、同２２２、Ｃ．Ｉ．ピグメントオレンジ３１、同４３、Ｃ．Ｉ．ピグメントイエロー１４、同１７、同９３、同９４、同１３８、Ｃ．Ｉ．ピグメントグリーン７、Ｃ．Ｉ．ピグメントブルー１５：３、同６０等を用いる事ができ、これらの混合物も用いる事ができる。数平均一次粒子径は種類により多様であるが、概ね１０〜２００ｎｍ程度が好ましい。
【０１７７】
着色剤の添加方法としては、乳化重合法で調製した重合体粒子を、凝集剤を添加することで凝集させる段階で添加し重合体を着色する方法や、単量体を重合させる段階で着色剤を添加し、重合し、着色粒子とする方法等を使用することができる。なお、着色剤は重合体を調製する段階で添加する場合はラジカル重合性を阻害しない様に表面をカップリング剤等で処理して使用することが好ましい。
【０１７８】
さらに、定着性改良剤としての低分子量ポリプロピレン（数平均分子量＝１５００〜９０００）や低分子量ポリエチレン等を添加してもよい。
【０１７９】
荷電制御剤も同様に種々の公知のもので、且つ水中に分散することができるものを使用することができる。具体的には、ニグロシン系染料、ナフテン酸または高級脂肪酸の金属塩、アルコキシル化アミン、第４級アンモニウム塩化合物、アゾ系金属錯体、サリチル酸金属塩あるいはその金属錯体等が挙げられる。
【０１８０】
なお、これら荷電制御剤や定着性改良剤の粒子は、分散した状態で数平均一次粒子径が１０〜５００ｎｍ程度とすることが好ましい。
【０１８１】
本発明のトナーでは、外添剤として無機微粒子や有機微粒子などの微粒子を添加して使用することでより効果を発揮することができる。この理由としては、外添剤の埋没や脱離を効果的に抑制することができるため、その効果が顕著にでるものと推定される。
【０１８２】
この無機微粒子としては、シリカ、チタニア、アルミナ等の無機酸化物粒子の使用が好ましく、さらに、これら無機微粒子はシランカップリング剤やチタンカップリング剤等によって疎水化処理されていることが好ましい。疎水化処理の程度としては特に限定されるものでは無いが、メタノールウェッタビリティーとして４０〜９５のものが好ましい。メタノールウェッタビリティーとは、メタノールに対する濡れ性を評価するものである。この方法は、内容量２００ｍｌのビーカー中に入れた蒸留水５０ｍｌに、測定対象の無機微粒子を０．２ｇ秤量し添加する。メタノールを先端が液体中に浸せきされているビュレットから、ゆっくり攪拌した状態で無機微粒子の全体が濡れるまでゆっくり滴下する。この無機微粒子を完全に濡らすために必要なメタノールの量をａ（ｍｌ）とした場合に、下記式により疎水化度が算出される。
【０１８３】
疎水化度＝（ａ／（ａ＋５０））×１００
この外添剤の添加量としては、トナー中に０．１〜５．０質量％、好ましくは０．５〜４．０質量％である。また、外添剤としては種々のものを組み合わせて使用してもよい。
【０１８４】
いわゆる重合性単量体中に着色剤などのトナー構成成分を分散あるいは溶解したものを水系媒体中に懸濁し、ついで重合せしめてトナーを得る懸濁重合法トナーでは、重合反応を行う反応容器中での媒体の流れを制御することによりトナー粒子の形状を制御することができる。すなわち、形状係数が１．２以上の形状を有するトナー粒子を多く形成させる場合には、反応容器中での媒体の流れを乱流とし、重合が進行して懸濁状態で水系媒体中に存在している油滴が次第に高分子化することで油滴が柔らかい粒子となった時点で、粒子の衝突を行うことで粒子の合一を促進させ、形状が不定形となった粒子が得られる。また、形状係数が１．２より小さいほぼ球形のトナー粒子を形成させる場合には、反応容器中での媒体の流れを層流として、粒子の衝突を避けることによりほぼ球形の粒子が得られる。この方法により、トナー形状の分布を本発明の範囲内に制御できるものである。
【０１８５】
次に、重合トナーの製造に好ましく用いられる反応装置について説明する。図３および図４は、それぞれ、重合トナー反応装置の一例を示す斜視図および断面図である。図３および図４に示す反応装置において、熱交換用のジャケット１ｊを外周部に装着した縦型円筒状の攪拌槽２ｊ内の中心部に回転軸３ｊを垂設し、該回転軸３ｊに攪拌槽２ｊの底面に近接させて配設された下段の攪拌翼４０ｊと、より上段に配設された攪拌翼５０ｊとが設けられている。上段の攪拌翼５０ｊは、下段に位置する攪拌翼４０ｊに対して回転方向に先行した交差角αをもって配設されている。本発明のトナーを製造する場合において、交差角αは９０度（°）未満であることが好ましい。この交差角αの下限は特に限定されるものでは無いが、５°程度以上であることが好ましく、更に、好ましくは１０°以上である。なお、三段構成の攪拌翼を設ける場合には、それぞれ隣接している攪拌翼間で交差角αが９０度未満であることが好ましい。
【０１８６】
このような構成とすることで、上段に配設されている攪拌翼５０ｊによりまず媒体が攪拌され、下側への流れが形成される。ついで、下段に配設された攪拌翼４０ｊにより、上段の攪拌翼５０ｊで形成された流れがさらに下方へ加速されるとともにこの攪拌翼５０ｊ自体でも下方への流れが別途形成され、全体として流れが加速されて進行するものと推定される。この結果、乱流として形成された大きなズリ応力を有する流域が形成されるために、得られるトナー粒子の形状を制御できるものと推定される。
【０１８７】
なお、図３および図４中、矢印は回転方向を示し、７ｊは上部材料投入口、８ｊは下部材料投入口、９ｊは攪拌を有効にするための乱流形成部材である。
【０１８８】
ここにおいて攪拌翼の形状については、特に限定はないが、方形板状のもの、翼の一部に切り欠きのあるもの、中央部に一つ以上の中孔部分、いわゆるスリットがあるものなどを使用することができる。これらの具体例を図５に記載する。図５（ａ）に示す攪拌翼５ａは中孔部のないもの、同図（ｂ）に示す攪拌翼５ｂは中央に大きな中孔部６ｂがあるもの、同図（ｃ）に示す攪拌翼５ｃは横長の中孔部６ｃ（スリット）があるもの、同図（ｄ）に示す攪拌翼５ｄは縦長の中孔部６ｄ（スリット）があるものである。また、三段構成の攪拌翼を設ける場合において、上段の攪拌翼に形成される中孔部と、下段の攪拌翼に形成される中孔部とは異なるものであっても、同一のものであってもよい。
【０１８９】
なお、上記の構成を有する上段と下段の攪拌翼の間隙は特に限定されるものでは無いが、少なくとも攪拌翼の間に間隙を有していることが好ましい。この理由としては明確では無いが、その間隙を通じて媒体の流れが形成されるため、攪拌効率が向上するものと考えられる。但し、間隙としては、静置状態での液面高さに対して０．５〜５０％の幅、好ましくは１〜３０％の幅である。
【０１９０】
さらに、攪拌翼の大きさは特に限定されるものでは無いが、全攪拌翼の高さの総和が静置状態での液面高さの５０％〜１００％、好ましくは６０％〜９５％である。
【０１９１】
一方、樹脂粒子を水系媒体中で会合あるいは融着させる重合法トナーでは、融着段階での反応容器内の媒体の流れおよび温度分布を制御することで、さらには融着後の形状制御工程において加熱温度、攪拌回転数、時間を制御することで、トナー全体の形状分布および形状を任意に変化させることができる。
【０１９２】
すなわち、樹脂粒子を会合あるいは融着させる重合法トナーでは、反応装置内の流れを層流とし、内部の温度分布を均一化することができる攪拌翼および攪拌槽を使用して、融着工程および形状制御工程での温度、回転数、時間を制御することにより、所期の形状係数および均一な形状分布を有するトナーを形成することができる。この理由は、層流を形成させた場で融着させると、凝集および融着が進行している粒子（会合あるいは凝集粒子）に強いストレスが加わらず、かつ流れが加速された層流においては攪拌槽内の温度分布が均一である結果、融着粒子の形状分布が均一になるからであると推定される。さらに、その後の形状制御工程での加熱、攪拌により融着粒子は徐々に球形化し、トナー粒子の形状を任意に制御できる。
【０１９３】
樹脂粒子を会合あるいは融着させる重合法トナーを製造する際に使用される攪拌槽としては、前述の懸濁重合法と同様のものが使用できる。この場合、攪拌槽内には乱流を形成させるような邪魔板等の障害物を設けないことが必要である。
【０１９４】
この攪拌翼の形状についても、層流を形成させ、乱流を形成させないものであれば特に限定されないが、図５（ｃ）に示した方形板状のもの等、連続した面により形成されるものが好ましく、曲面を有していてもよい。
【０１９５】
本発明のトナーは、例えば磁性体を含有させて一成分磁性トナーとして使用する場合、いわゆるキャリアと混合して二成分現像剤として使用する場合、非磁性トナーを単独で使用する場合等が考えられ、いずれも好適に使用することができるが、本発明ではキャリアと混合して使用する二成分現像剤として使用することが好ましい。
【０１９６】
次に、本発明の画像形成装置について説明する。
図１は、本発明の電子ＲＤＨを用いて、有機感光体上に形成されたトナー像を記録紙に転写・定着し、両面画像を形成する画像形成方法に、好適に使用することができる画像形成装置（デジタル複写機）の全体構成を示す図である。
【０１９７】
この図１において、デジタル複写機は、画像読み取り部Ａ、画像処理部Ｂ、画像記憶部Ｃ、画像形成部Ｄで構成される。前記画像読み取り部Ａが読み取り手段に、画像処理部Ｂが画像処理手段に、画像記憶部Ｃが画像データ記憶手段に、また、前記画像形成部Ｄが画像形成手段に相当する。
【０１９８】
画像読み取り部Ａにおいて、原稿１２１は原稿台ガラス（以下プラテンガラスと略記する）１２２上に記載され、図示を省略したガイドレール上を移動するキャリッジに設けられたハロゲン光源１２３によって照明される。一対のミラー１２４，１２５が設けられた可動ミラーユニット１２６は、前記スライドレール上を移動し、前記キャリッジに設けられているミラー１２７との組合せで、プラテンガラス１２２上の原稿１２１からの反射光即ち光学像を、レンズ読み取りユニット１２８へ導出する。前記レンズ読み取りユニット１２８は結像レンズ１２９及びＣＣＤラインセンサ１３０から構成される。前記ミラー１２４，１２５，１２７により反射伝達された原稿１２１上の画像に対応する光学像は、前記結像レンズ１２９により収束され、ＣＣＤラインセンサ１３０の受光面に結像され、前記ＣＣＤラインセンサ１３０によりライン上の光学像が順次電気信号に光電変換される。
【０１９９】
操作部２８に設けられたコピーボタンを押すと、図示を省略したモーターによって連動して駆動されるハロゲン光源１２３とミラー１２７が設けられているキャリッジと可動ミラーユニット１２６との動きにより１頁分の原稿の画像情報はＣＣＤラインセンサ１３０に読み取られる。プラテンガラス１２２上に１枚ずつ置かれた原稿１２１は以上のように順次読み取られてそれぞれ１頁分の画像データとして出力される。
【０２００】
前記画像読み取り部Ａで読み取りられた原稿画像の画像信号即ち画像データは、後述する画像処理部Ｂにおいて、濃度変換、フィルタ処理、変倍処理、γ補正などの各種画像処理が施された後、画像記憶部Ｃを経て画像形成部Ｄに出力される。画像形成部Ｄは、電子写真技術を用いたレーザプリンタにより、入力された画像データに応じて記録紙上に画像形成を行う。
【０２０１】
即ち、画像形成部Ｄでは、図示しない半導体レーザで発生されるレーザビームを画像信号に基づいて変調する。かかるレーザビームを駆動モータ１４１により回転されるポリゴンミラー１４２で回転走査させ、図示しないｆθレンズを経て、反射ミラー１４３により光路を曲げて、感光体ドラム１５１の表面上に投射させ、一様に帯電された感光体ドラム１５１上に静電潜像を形成する。ここに、感光体ドラム１５１としては、環境保護、無公害の観点から有機感光体からなることが好ましい。
【０２０２】
更に、この感光体ドラム１５１を一様に帯電させるための帯電器（帯電工程でもある）１５２、現像器（現像工程でもある）１５３、転写極（転写工程でもある）１５７、分離極（分離工程でもある）１５８、クリーニング装置（クリーニング工程でもある）１５９、定着装置（定着工程でもある）１６０が備えられており、感光体ドラム１５１上に形成された静電潜像が前記現像器１５３によって現像されてトナー像となり、更に、前記トナー像が記録紙上に転写され、定着されて、原稿の複写像が得られるようにされている。
【０２０３】
記録紙は各サイズ毎にカセット１７１〜１７４にストックされており、記録紙サイズの指示に従って対応するカセット１７１〜１７４から記録紙が取り出され、複数の搬送ローラや搬送ベルトを含んで構成される記録紙搬送機構１７５とによって感光体ドラム１５１に供給される。
【０２０４】
片面コピーの場合はカセットから順次取り出される記録紙の片面に、トナー像が順次転写、定着されて記録紙排出トレイ１７６上に排出される。
【０２０５】
両面コピーの場合は片面にトナー像が転写、定着されて送りだされた記録紙が記録紙搬送路中の定着装置１６０直後に配置された第１の切替え爪１７７（図中の破線の位置）により下方に方向転換され両面複写ユニット（Ａｕｔｏ　Ｄｕｐｌｅｘ　Ｕｎｉｔ，以下ＡＤＵと略記する）へと案内される。記録紙搬送路中の第２の切替え爪１８０（図中の破線の位置）は記録紙を右方向へ通過させ次に反転ローラー１８１が逆転すると同時に第２の切替え爪を図中の実線の位置に切り換える。この結果記録紙は表裏逆転された後反転搬送路１８３を経てカセット１７１、１７２からの給紙と同様に感光体ドラム１５１へと給送される。原稿裏面の画像データは画像記憶部Ｃから読み出されて記録紙裏面に順次画像形成されて両面コピーが得られる。
【０２０６】
また、図１に示すデジタル複写機には、前記プラテンガラス１２２上に読み取り原稿１２１を自動搬送する自動原稿送り装置８１が、前記画像読み取り部Ａに設けられている。前記自動原稿送り装置８１は、原稿セット台８２上に読み取り原稿を複数枚重ねてセットし、コピーボタンを押すと、この原稿の各ページを順次給送して順番にプラテンガラス１２２上の所定位置に自動搬送するとともに、読み取りの終了した原稿１２１をプラテンガラス１２２上から取除いて原稿排出トレー９４上に排出するものである。
【０２０７】
更に、前記自動原稿送り装置８１は、前記のように原稿の片面に画像の記された片面原稿１２１を順次送り出して読み取る他、両面原稿を１枚取り出してプラテンガラス１２２上に送り込んで片面の画像読み取りを終えると前記原稿を逆方向に移動させ、反転ガイドと反転ローラーからなる反転部で方向を転換して原稿を裏返してプラテンガラス１２２の所定位置に送り込み原稿裏面の画像情報を読み取りできるようにされている。
【０２０８】
前記説明したような原稿の自動搬送のために、原稿セット台８２上の原稿を１枚づつ送り出す給紙ローラ８３と、駆動ローラ８４及び従動ローラ９２と、前記駆動ローラ８４及び従動ローラ９２によって巻回し駆動されるベルト８６と、ガイド板８９と反転ローラー９０と図示されないソレノイドで駆動される切り換えガイド８８を含む反転部と原稿排出ローラー８７が設けられている。
【０２０９】
このような自動原稿送り装置を用いると両面原稿でも片面原稿でも順次プラテンガラス１２２上の所定の読み取り位置に原稿１２１を自動的に送りだして読み取り画像信号として出力させることが出来る。
【０２１０】
本発明で、電子ＲＤＨ（Ｒｅｃｉｒｃｕｌａｔｉｎｇ　Ｄｏｃｕｍｅｎｔ　Ｈａｎｄｌｅｒ）を用いて記録紙に両面画像を形成する画像形成方法とは、従来のアナログ複写機で両面を画像形成する方式とは異なり、記録紙の一面に画像形成したものをストックする必要がなく、直ちに記録紙の他面に連続して画像形成し両面画像を形成することを云う。即ち、電子画像に変換された画像情報に基づき、感光体上に第１のデジタル静電潜像を形成し、該静電潜像をトナー像にした後、該トナー像を記録紙の一面に転写・定着した後、該記録紙をストックすることなく直ちに、他面の転写工程・定着工程へ搬送し、前記有機感光体上に形成された第２の電子画像に基づくトナー像を転写・定着し、両面画像を形成することを意味する。
【０２１１】
又、上記画像形成装置において、感光体と、現像器、帯電器、転写極、分離極及びクリーニング装置の少なくとも１つが一体化されている着脱可能なプロセスカートリッジを形成してもよい。
【０２１２】
本発明の有機感光体及び画像形成方法、画像形成装置、プロセスカートリッジは電子写真複写機、レーザプリンター、ＬＥＤプリンター及び液晶シャッター式プリンター等の電子写真装置一般に適応するが、更に、電子写真技術を応用したディスプレー、記録、軽印刷、製版及びファクシミリ等の装置にも幅広く適用することができる。
【０２１３】
【実施例】
以下、実施例をあげて本発明を詳細に説明するが、本発明の様態はこれに限定されない。文中の「部」は質量部を表す。
【０２１４】
実施例１
合成例１（例示化合物Ｔ２０の合成例）
【０２１５】
【化３２】

【０２１６】
上記式で表される化合物１０ｇをオキシ塩化リン３２ｇに溶解させ、５０℃まで加熱しジメチルホルムアミド２２ｍｌを少しずつ滴下した（発熱し４０〜７０℃になる）。反応液を９０℃前後にコントロールしながら、１５時間撹拌した。４０℃まで放冷した後、余分なオキシ塩化リンを十分に加水分解し析出した結晶をろ別し、水で懸濁して洗浄し、洗液が中性になるまで洗浄を繰り返し下記構造式で表されるビスホルミル化合物９．２５ｇ（７７％）を得た。
【０２１７】
【化３３】

【０２１８】
上記得られたビスホルミル化合物２ｇと、下記構造式で表されるホスホネート化合物４．３ｇをジメチルホルムアミド２０ｍｌに溶解した。反応液を２０℃前後に保ちながら、ナトリウムメトキシド１．０ｇを少しずつ添加した（発熱有り）。４時間撹拌後、水３０ｍｌを加え常法により精製処理を行って黄色結晶３．３ｇ（８１％）を得た。この化合物を、元素分析及び質量分析を行ったところ、下記表１のような結果となり例示化合物Ｔ２０であることが確認された。
【０２１９】
【化３４】

【０２２０】
元素分析（Ｃ_５３Ｈ_４９Ｎ）
【０２２１】
【表１】

【０２２２】
質量分析（Ｃ_５３Ｈ_４９Ｎ）
Ｍｗ（計算値）＝６９９
Ｍｗ^＋（実測値）＝６９９
上記の合成で得られたＴ２０の化合物をＴ２０−１とする。このＴ２０−１は下記液体クロマトグラフィ（ＨＰＣＬ）の測定結果ｃｉｓ−ｃｉｓ／ｃｉｓ−ｔｒａｎｓ／ｔｒａｎｓ−ｔｒａｎｓ混合比が１．１／２．２／１．０であった。尚、Ｔ２０ｃｉｓ−ｃｉｓ、Ｔ２０ｔｒａｎｓ−ｔｒａｎｓ、Ｔ２０ｃｉｓ−ｔｒａｎｓの構造式を下記に示す。
【０２２３】
液体クロマトグラフィの測定条件
測定機：島津ＬＣ６Ａ（島津製作所製）
カラム：ＣＬＣ−ＳＩＬ（島津製作所製）
検出波長：２９０ｎｍ
移動相：ｎ−ヘキサン／ジオキサン＝１０〜５００／１
移動相の流速：約１ｍｌ／ｍｉｎ
サンプル（Ｔ２０）溶媒：ｎ−ヘキサン／ジオキサン＝１０／１
サンプル（Ｔ２０）：３ｍｇ／溶媒１０ｍｌ
【０２２４】
【化３５】

【０２２５】
上記で得られたＴ２０−１を液体クロマトグラフィを用いてｃｉｓ−ｃｉｓ体、ｃｉｓ−ｔｒａｎｓ体、ｔｒａｎｓ−ｔｒａｎｓ体に分離した化合物も得た。これらｃｉｓ−ｃｉｓ体のＴ２０をＴ２０ｃ−ｃ、ｃｉｓ−ｔｒａｎｓ体のＴ２０をＴ２０ｃ−ｔ、ｔｒａｎｓ−ｔｒａｎｓ体のＴ２０をＴ２０ｔ−ｔとする。Ｔ２０−１とＴ２０ｃ−ｃ、Ｔ２０ｃ−ｔ、Ｔ２０ｔ−ｔの４つの化合物を用い、混合比を変えて、表２に示す如くｃｉｓ−ｃｉｓ／ｃｉｓ−ｔｒａｎｓ／ｔｒａｎｓ−ｔｒａｎｓの混合比を持つＴ２０−２〜Ｔ２０−８の化合物を作製した。
【０２２６】
感光体１の作製

酸化チタン、ポリアミド樹脂、メタノールを同一容器中に加え超音波ホモジナイザーを用いて分散し、中間層用の塗布液を調製した。この塗布液を円筒状アルミニウム基体上に浸漬塗布し、１１０℃、１時間の加熱硬化を行い、４μｍの乾燥膜厚で中間層を設けた。
【０２２７】

を混合し、サンドミルを用いて１０時間分散し、電荷発生層塗布液を調製した。この塗布液を前記中間層の上に浸漬塗布法で塗布し、乾燥膜厚０．２μｍの電荷発生層を形成した。
【０２２８】

を混合し、溶解して電荷輸送層塗布液を調製した。この塗布液を前記電荷発生層の上に浸漬塗布法で塗布し、乾燥膜厚２４μｍの電荷輸送層を形成し、感光体１を作製した。
【０２２９】
感光体２〜９の作製
感光体１で用いた電荷輸送物質（Ｔ２０−１）をＴ２０−２〜Ｔ２０−８、Ｔ２０ｔ−ｔに代え、異性体混合比を表２のように変えた以外は感光体１と同様にして感光体２〜９を作製した。
【０２３０】
【表２】

【０２３１】
トナー及び現像剤の作製
（トナー製造例１：乳化重合会合法の例）
ｎ−ドデシル硫酸ナトリウム０．９０ｋｇと純水１０．０リットルを入れ攪拌溶解した。この溶液に、リーガル３３０Ｒ（キャボット社製カーボンブラック）１．２０ｋｇを徐々に加え、１時間よく攪拌した後に、サンドグラインダー（媒体型分散機）を用いて、２０時間連続分散した。このものを「着色剤分散液１」とする。
【０２３２】
また、ドデシルベンゼンスルホン酸ナトリウム０．０５５ｋｇとイオン交換水４．０リットルとからなる溶液を「アニオン界面活性剤溶液Ａ」とする。
【０２３３】
ノニルフェノールポリエチレンオキサイド１０モル付加物０．０１４ｋｇとイオン交換水４．０リットルとからなる溶液を「ノニオン界面活性剤溶液Ｂ」とする。
【０２３４】
過硫酸カリウム２２３．８ｇをイオン交換水１２．０リットルに溶解した溶液を「開始剤溶液Ｃ」とする。
【０２３５】
温度センサー、冷却管、窒素導入装置を付けた容積１００リットルのＧＬ（グラスライニング）反応釜に、ＷＡＸエマルジョン（数平均分子量３０００のポリプロピレンエマルジョン：数平均一次粒子径＝１２０ｎｍ／固形分濃度＝２９．９％）３．４１ｋｇと「アニオン界面活性剤溶液Ａ」全量と「ノニオン界面活性剤溶液Ｂ」全量とを入れ、攪拌を開始した。次いで、イオン交換水４４．０リットルを加えた。
【０２３６】
加熱を開始し、液温度が７５℃になったところで、「開始剤溶液Ｃ」全量を滴下して加えた。その後、液温度を７５℃±１℃に制御しながら、スチレン１２．１ｋｇとアクリル酸ｎ−ブチル２．８８ｋｇとメタクリル酸１．０４ｋｇとｔ−ドデシルメルカプタン５４８ｇとを滴下しながら投入した。滴下終了後、液温度を８０℃±１℃に上げて、６時間加熱攪拌を行った。ついで、液温度を４０℃以下に冷却し攪拌を停止し、ポールフィルターで濾過してラテックスを得た。これを「ラテックス−Ａ」とする。
【０２３７】
なお、ラテックス−Ａ中の樹脂粒子のガラス転移温度は５７℃、軟化点は１２１℃、分子量分布は、重量平均分子量＝１．２７万、重量平均粒径は１２０ｎｍであった。
【０２３８】
ドデシルベンゼンスルホン酸ナトリウム０．０５５ｋｇをイオン交換純水４．０リットルに溶解した溶液を「アニオン界面活性剤溶液Ｄ」とする。
【０２３９】
また、ノニルフェノールポリエチレンオキサイド１０モル付加物０．０１４ｋｇをイオン交換水４．０リットルに溶解した溶液を「ノニオン界面活性剤溶液Ｅ」とする。
【０２４０】
過硫酸カリウム（関東化学社製）２００．７ｇをイオン交換水１２．０リットルに溶解した溶液を「開始剤溶液Ｆ」とする。
【０２４１】
温度センサー、冷却管、窒素導入装置、櫛形バッフルを付けた１００リットルのＧＬ反応釜に、ＷＡＸエマルジョン（数平均分子量３０００のポリプロピレンエマルジョン：数平均一次粒子径＝１２０ｎｍ／固形分濃度　２９．９％）３．４１ｋｇと「アニオン界面活性剤溶液Ｄ」全量と「ノニオン界面活性剤溶液Ｅ」全量とを入れ、攪拌を開始した。
【０２４２】
次いで、イオン交換水４４．０リットルを投入した。加熱を開始し、液温度が７０℃になったところで、「開始剤溶液Ｆ」を添加した。ついで、スチレン１１．０ｋｇとアクリル酸ｎ−ブチル４．００ｋｇとメタクリル酸１．０４ｋｇとｔ−ドデシルメルカプタン９．０２ｇとをあらかじめ混合した溶液を滴下した。滴下終了後、液温度を７２℃±２℃に制御して、６時間加熱攪拌を行った。さらに、液温度を８０℃±２℃に上げて、１２時間加熱攪拌を行った。液温度を４０℃以下に冷却し攪拌を停止した。ポールフィルターで濾過し、この濾液を「ラテックス−Ｂ」とする。
【０２４３】
なお、ラテックス−Ｂ中の樹脂粒子のガラス転移温度は５８℃、軟化点は１３２℃、分子量分布は、重量平均分子量＝２４．５万、重量平均粒径は１１０ｎｍであった。
【０２４４】
塩析剤としての塩化ナトリウム５．３６ｋｇをイオン交換水２０．０リットルに溶解した溶液を「塩化ナトリウム溶液Ｇ」とする。
【０２４５】
フッ素系ノニオン界面活性剤１．００ｇをイオン交換水１．００リットルに溶解した溶液を「ノニオン界面活性剤溶液Ｈ」とする。
【０２４６】
温度センサー、冷却管、窒素導入装置、粒径および形状のモニタリング装置を付けた１００リットルのＳＵＳ反応釜（図３に示した構成の反応装置，交差角αは２５°）に、上記で作製したラテックス−Ａ＝２０．０ｋｇとラテックス−Ｂ＝５．２ｋｇと着色剤分散液１＝０．４ｋｇとイオン交換水２０．０ｋｇとを入れ攪拌した。ついで、４０℃に加温し、塩化ナトリウム溶液Ｇ、イソプロパノール（関東化学社製）６．００ｋｇ、ノニオン界面活性剤溶液Ｈをこの順に添加した。その後、１０分間放置した後に、昇温を開始し、液温度８５℃まで６０分で昇温し、８５±２℃にて０．５〜３時間加熱攪拌して塩析／融着させながら粒径成長させた（塩析／融着工程）。次に純水２．１リットルを添加して粒径成長を停止させ、融着粒子分散液を作製した。
【０２４７】
温度センサー、冷却管、粒径および形状のモニタリング装置を付けた５リットルの反応容器（図３に示した構成の反応装置，交差角αは２０°）に、上記で作製した融着粒子分散液５．０ｋｇを入れ、液温度８５℃±２℃にて、０．５〜１５時間加熱攪拌して形状制御した（形状制御工程）。その後、４０℃以下に冷却し攪拌を停止した。次に遠心分離機を用いて、遠心沈降法により液中にて分級を行い、目開き４５μｍの篩いで濾過し、この濾液を会合液とする。ついで、ヌッチェを用いて、会合液よりウェットケーキ状の非球形状粒子を濾取した。その後、イオン交換水により洗浄した。この非球形状粒子をフラッシュジェットドライヤーを用いて吸気温度６０℃にて乾燥させ、ついで流動層乾燥機を用いて６０℃の温度で乾燥させた。得られた着色粒子の１００質量部に、シリカ微粒子１質量部をヘンシェルミキサーにて外添混合して乳化重合会合法によるトナーを得た。
【０２４８】
前記塩析／融着工程および形状制御工程のモニタリングにおいて、攪拌回転数、および加熱時間を制御することにより、形状および形状係数の変動係数を制御し、さらに液中分級により、粒径および粒度分布の変動係数を任意に調整して、表３に示す形状特性および粒度分布特性を有するトナー粒子からなるトナー１〜１６を得た。
【０２４９】
【表３】

【０２５０】
〔現像剤の製造〕
トナー１〜１６の各々１０質量部と、スチレン−メタクリレート共重合体で被覆した４５μｍフェライトキャリア１００質量部とを混合することにより、評価用の現像剤１〜１６を製造した。
【０２５１】
評価
上記感光体１〜９と現像剤１〜１６を表４のように組み合わせ、評価機としてコニカ社製デジタル複写機Ｋｏｎｉｃａ７０７５（コロナ帯電、レーザ露光、反転現像、静電転写、爪分離、ブレードクリーニング、クリーニングローラ、電子ＲＤＨを用いて、両面画像を形成するプロセスを有する）を用い評価した。クリーニング性及び画像評価は、画素率が７％の文字画像、人物顔写真、ベタ白画像、ベタ黒画像がそれぞれ１／４等分にあるオリジナル画像をＡ４中性紙に両面コピーして行った。複写条件は最も厳しいと思われる高温高湿環境（３０℃８０％ＲＨ）にて連続２０万枚コピー行い、評価を行った。但し、コピー開始前に、感光体表面にセッティングパウダーをまぶし、感光体とクリーニングブレードをなじませた後２０万枚の両面コピーを行った。評価項目及び評価基準を下記に示す。
【０２５２】
【表４】

【０２５３】
評価項目及び評価基準
画像濃度（マクベス社製反射濃度計「ＲＤ−９１８」を使用して測定。紙の反射濃度を「０」とした相対反射濃度で測定した。初期と２０万枚コピー後の両方で評価）
◎：初期と２０万枚コピー後の両方共１．２以上（良好）
○：初期と２０万枚コピー後の両方共１．０以上（実用上問題ないレベル）
×：初期と２０万枚コピー後の少なくとも一方が１．０未満
（実用上問題となるレベル）
カブリ：ベタ白画像濃度で判定
マクベス社製反射濃度計「ＲＤ−９１８」を用いて、印字されていないコピー用紙（白紙）の濃度を２０カ所、絶対画像濃度で測定し、その平均値を白紙濃度とする。次に、画像形成がなされた評価用紙の白地部分を同様に２０カ所、絶対画像濃度で測定し、その平均濃度から前記白紙濃度を引いた値をカブリ濃度として評価した。
【０２５４】
◎：初期と２０万枚コピー後の両方共０．００５以下（良好）
○：初期と２０万枚コピー後の両方共０．０１以下（実用上問題ないレベル）
×：初期と２０万枚コピー後の少なくとも一方が０．０１より大（明らかに、実用上問題あり）
解像度（文字画像の判別容易性で判定）
上記２０万枚のコピー後に、３ポイント、５ポイントの文字画像を形成し、下記の判断基準で評価した。
【０２５５】
◎：３ポイント、５ポイントとも明瞭であり、容易に判読可能（良好）
○：３ポイントは一部判読不能、５ポイントは明瞭であり、容易に判読可能
（実用上問題ないレベル）
×：３ポイントは殆ど判読不能、５ポイントも一部あるいは全部が判読不能
クリーニング性（１０万及び２０万枚コピー終了後にＡ３紙に連続１０枚複写を行い、ベタ白部でのクリーニング不良の発生の有無で判定）
◎：２０万枚までトナーのすり抜け発生なし（良好）
○：１０万枚までトナーのすり抜け発生なし（実用上問題ないレベル）
×：１０万枚未満でトナーのすり抜け発生（実用上問題となるレベル）
白ヌケ（上記２０万枚コピー後、更にハーフトーン画像１００枚を作製して評価）
白ヌケの評価は、周期性が感光体の周期と一致し、長径が０．４ｍｍ以上の白ヌケがＡ４紙当たり何個あるかで判定した。
【０２５６】
◎：０．４ｍｍ以上の白ヌケ頻度：全ての複写画像が３個／Ａ４以下（良好）
○：０．４ｍｍ以上の白ヌケ頻度：４個／Ａ４以上、１９個／Ａ４以下が１枚以上発生（実用上問題ないレベル）
×：０．４ｍｍ以上の白ヌケ頻度：２０個／Ａ４以上が１枚以上発生
（実用上問題となるレベル）
黒ポチ（上記２０万枚コピー後、更にベタ白のコピー画像１００枚を作製して評価）
黒ポチについては、周期性が感光体の周期と一致し、目視できる黒ポチが、Ａ４サイズ当たり何個あるかで判定した。
【０２５７】
◎：０．４ｍｍ以上の黒ポチ頻度：全ての複写画像が３個／Ａ４以下（良好）
○：０．４ｍｍ以上の黒ポチ頻度：４個／Ａ４以上、１９個／Ａ４以下が１枚以上発生（実用上問題ないレベル）
×：０．４ｍｍ以上の黒ポチ頻度：２０個／Ａ４以上が１枚以上発生
（実用上問題となるレベル）
クラック
前記連続２０万枚の両面コピー後、Ｋｏｎｉｃａ７０７５を３０℃８０％ＲＨの環境下で、感光体を搭載したまま、電源をｏｆｆにし、２日間放置した。感光体周辺の部材はこの間動作を停止しているだけの状態、即ち、クリーニングブレード、クリーニングローラ、現像剤搬送体等の部材は、感光体に当接したままにした。その後、感光体の表面を観察し、クラックの発生の有無を観察、画像だし（画像上にクラックの発生に伴う筋状の画像が出現しているかを検出）も行った。
【０２５８】
◎：クラック及び筋状の画像欠陥の発生なし（良好）
◯：微細なクラックの発生はあるが、筋状の画像欠陥の発生は見られない（実用上、問題なし）
×：クラックが発生し、筋状の画像欠陥も発生している（実用上、問題あり）
その他評価条件
尚、上記Ｋｏｎｉｃａ７０７５を用いたその他の評価条件は下記の条件に設定した。
【０２５９】
帯電条件
帯電器；スコロトロン帯電器、初期帯電電位を−７５０Ｖ
露光条件
７８０ｎｍの半導体レーザを露光光源とした
転写条件
転写極；コロナ帯電方式
クリーニング条件
クリーニング部に硬度７０°、反発弾性６５％、厚さ２（ｍｍ）、自由長９ｍｍのクリーニングブレードをカウンター方向に線圧１８（Ｎ／ｍ）となるように重り荷重方式で当接した。
【０２６０】
クリーニングローラ：表面が発泡性ウレタン樹脂で被覆されたローラを用いた。
【０２６１】
評価結果を表５に示した。
【０２６２】
【表５】

【０２６３】
表５から明らかなように、電子ＲＤＨを用いて両面コピーを行う画像形成方法の評価において、本発明の有機感光体とトナーを用いた組み合わせＮｏ．１〜１５、１７〜２３は白ヌケ、黒ポチ、クリーニング性等の各評価が実用上問題のないレベル以上であるのに対し、本発明外の組み合わせＮｏ．１６（トナーが本発明外）は、白ヌケ、クリーニング性の劣化が著しく、解像度が低下している。Ｎｏ．２４（感光体が本発明外）は白ヌケ、黒ポチの発生が著しく、クラックも発生し、解像度が低下している。又、Ｎｏ．２５（トナー及び感光体が本発明外）は白ヌケ及び黒ポチ共発生しており、クラックも発生し、クリーニング性も劣化し、解像度が低下している。又、本発明の有機感光体とトナーを用いた組み合わせＮｏ．１〜１５、１７〜２３の中でも、立体異性体混合物中に占める最多異性体成分の含有率が４０〜９０質量％である電荷輸送物質を含有する電荷輸送層を表面層として有する感光体を用いた組み合わせＮｏ．１〜１５、１７、１９〜２１は含有率が３７．５及び９２．５の感光体を用いた組み合わせＮｏ．１８、２２、２３に比し、改良効果が勝っている。又、トナーは前記▲２▼及び▲５▼の条件を満たした組み合わせＮｏ．１〜３、５〜７、１０、１１、１９〜２１等が▲２▼及び▲５▼の両方の条件を満たしていない組み合わせＮｏ．４、８、９、１２〜１５等に対し効果が勝っている。特に、前記▲１▼〜▲５▼の全ての条件を満たしたトナーと、立体異性体混合物中に占める最多異性体成分の含有率が４０〜９０質量％である電荷輸送物質を含有する電荷輸送層を表面層として有する感光体とを併用した、組み合わせＮｏ．１〜３及び１９〜２１は白ヌケ、黒ポチの両画像欠陥が顕著に改善されておりクリーニング性も良好で、、画像濃度や解像度等の評価も優れていることが見出される。
【０２６４】
実施例２
合成例１（例示化合物Ｔ８３の合成例）
【０２６５】
【化３６】

【０２６６】
上記式で表される化合物１０ｇをジメチルホルムアミド４０ｍｌに溶解させ、４０℃まで加熱しオキシ塩化リン９．２ｇを少しずつ滴下した（発熱し４０〜７０℃になる）。反応液を７０℃前後にコントロールしながら、３時間撹拌した。４０℃まで放冷した後余分なオキシ塩化リンを十分に加水分解し析出した結晶をろ別し、水で懸濁して洗浄し、洗液が中性になるまで洗浄を繰り返し下記構造式で表されるビスホルミル化合物９．２５ｇ（８５％）を得た。
【０２６７】
【化３７】

【０２６８】
上記得られたビスホルミル化合物４ｇと、シンナミルトリホスホニウムブロミド９．３ｇをテトラヒドロフラン５０ｍｌに溶解した。反応液を２０℃前後に保ちながら、ナトリウムメトキシド１．７ｇを少しずつ添加した（発熱有り）。２時間撹拌後、水３０ｍｌを加え常法により精製処理を行って黄色結晶３．３７ｇ（６２％）を得た。この化合物を、元素分析及び質量分析を行ったところ、下記表６のような結果となり例示化合物Ｔ８３であることが確認された。
【０２６９】
元素分析（Ｃ_５６Ｈ_４０Ｎ_２）
【０２７０】
【表６】

【０２７１】
質量分析（Ｃ_５６Ｈ_４０Ｎ_２）
Ｍｗ（計算値）＝７４０
Ｍｗ^＋（実測値）＝７４０
上記の合成で得られたＴ８３の化合物をＴ８３−１とする。このＴ８３−１は下記液体クロマトグラフィ（ＨＰＣＬ）の測定結果ｃｉｓ−ｃｉｓ／ｃｉｓ−ｔｒａｎｓ／ｔｒａｎｓ−ｔｒａｎｓ混合比が１．７／３．０／１．０であった。尚、Ｔ８３ｃｉｓ−ｃｉｓ、Ｔ８３ｔｒａｎｓ−ｔｒａｎｓの構造式を下記に示す。
【０２７２】
液体クロマトグラフィの測定条件
測定機：島津ＬＣ６Ａ（島津製作所製）
カラム：ＣＬＣ−ＳＩＬ（島津製作所製）
検出波長：２９０ｎｍ
移動相：ｎ−ヘキサン／ジオキサン＝１０〜５００／１
移動相の流速：約１ｍｌ／ｍｉｎ
サンプル（Ｔ８３）溶媒：ｎ−ヘキサン／ジオキサン＝１０／１
サンプル（Ｔ８３）：３ｍｇ／溶媒１０ｍｌ
【０２７３】
【化３８】

【０２７４】
上記で得られたＴ８３−１を液体クロマトグラフィを用いてｃｉｓ−ｃｉｓ体、ｃｉｓ−ｔｒａｎｓ体、ｔｒａｎｓ−ｔｒａｎｓ体に分離した化合物も得た。これらｃｉｓ−ｃｉｓ体のＴ８３をＴ８３ｃ−ｃ、ｃｉｓ−ｔｒａｎｓ体のＴ８３をＴ８３ｃ−ｔ、ｔｒａｎｓ−ｔｒａｎｓ体のＴ８３をＴ８３ｔ−ｔとする。Ｔ８３−１とＴ８３ｃ−ｃ、Ｔ８３ｃ−ｔ、Ｔ８３ｔ−ｔの４つの化合物を用い、混合比を変えて、表７に示す如くｃｉｓ−ｃｉｓ／ｃｉｓ−ｔｒａｎｓ／ｔｒａｎｓ−ｔｒａｎｓの混合比を持つＴ８３−２〜Ｔ８３−８の化合物を作製した。
【０２７５】
感光体１０〜１８の作製
感光体１〜９のＴ２０−１〜Ｔ２０−８、Ｔ２０ｔ−ｔをＴ８３−１〜Ｔ８３−８、Ｔ８３ｃ−ｃに代えた以外は同様にして感光体１０〜１８を作製した。
【０２７６】
【表７】

【０２７７】
評価
上記感光体１０〜１８と現像剤１〜１６を表８のように組み合わせ、実施例１と同様の評価を行った。評価結果を表９に記載する。
【０２７８】
【表８】

【０２７９】
【表９】

【０２８０】
表９から明らかなように、電子ＲＤＨを用いて両面コピーを行う画像形成方法の評価において、本発明の有機感光体とトナーを用いた組み合わせＮｏ．３１〜４５、４７〜５３は白ヌケ、黒ポチ、クリーニング性等の各評価が実用上問題のないレベル以上であるのに対し、本発明外の組み合わせＮｏ．４６（トナーが本発明外）は、白ヌケ、クリーニング性の劣化が著しく、解像度が低下している。Ｎｏ．５４（感光体が本発明外）は白ヌケ、黒ポチの発生が著しく、クラックも発生し、解像度が低下している。又、Ｎｏ．５５（トナー及び感光体が本発明外）は白ヌケ及び黒ポチ共発生しており、クラックも発生し、クリーニング性も劣化し、解像度が低下している。又、本発明の有機感光体とトナーを用いた組み合わせＮｏ．３１〜４５、４７〜５３の中でも、立体異性体混合物中に占める最多異性体成分の含有率が４０〜９０質量％である電荷輸送物質を含有する電荷輸送層を表面層として有する感光体を用いた組み合わせＮｏ．３１〜４５、４７、４９〜５１は含有率が３７．５及び９２．５の感光体を用いた組み合わせＮｏ．４８、５２、５３に比し、改良効果が勝っている。又、トナーは前記▲２▼及び▲５▼の条件を満たした組み合わせＮｏ．３１〜３３、３５〜３７、４０、４１、４９〜５１等が▲２▼及び▲５▼の両方の条件を満たしていない組み合わせＮｏ．３４、３８、３９、４２〜４５等に対し、効果が勝っている。特に、前記▲１▼〜▲５▼の全ての条件を満たしたトナーと、立体異性体混合物中に占める最多異性体成分の含有率が４０〜９０質量％である電荷輸送物質を含有する電荷輸送層を表面層として有する感光体とを併用した、組み合わせＮｏ．３１〜３３及び４９〜５１は白ヌケ、黒ポチの両画像欠陥が顕著に改善されておりクリーニング性も良好で、、画像濃度や解像度等の評価も優れていることが見出される。
【０２８１】
【発明の効果】
上記の実施例から明らかなように、本発明の有機感光体とトナーを組み合わせた画像形成方法は、感光体周辺の温湿度の変化が激しい電子ＲＤＨを用いた両面画像形成の画像形成方法に用いても、白ヌケや黒ポチ等の相反する画像欠陥の発生を防止し、クラックの発生も起こさず、クリーニング性に優れ、解像度が良好な電子写真画像を形成することができる。
【図面の簡単な説明】
【図１】本発明の電子ＲＤＨを用いて、有機感光体上に形成されたトナー像を記録紙に転写・定着し、両面画像を形成する画像形成方法に、好適に使用することができる画像形成装置（デジタル複写機）の全体構成を示す図である。
【図２】（ａ）は、角のないトナー粒子の投影像を示す説明図であり、（ｂ）および（ｃ）は、それぞれ角のあるトナー粒子の投影像を示す説明図である。
【図３】重合トナー反応装置の一例を示す斜視図である。
【図４】重合トナー反応装置の一例を示す断面図である。
【図５】攪拌翼の形状の具体例を示す概略図である。
【符号の説明】
Ａ　画像読み取り部
Ｂ　画像処理部
Ｃ　画像記憶部
Ｄ　画像形成部
２８　操作部
８１　自動原稿送り装置
８２　原稿セット台
８３　給紙ローラ
８４　駆動ローラ
８６　ベルト
８７　原稿排出ローラー
８８　切り換えガイド
８９　ガイド板
９０　反転ローラー
９２　従動ローラ
９４　原稿排出トレー
１２１　原稿
１２２　原稿台ガラス（プラテンガラス）
１２３　ハロゲン光源
１２４　ミラー
１２５　ミラー
１２６　可動ミラーユニット
１２７　ミラー
１２８　レンズ読み取りユニット
１２９　結像レンズ
１３０　ＣＣＤラインセンサ
１４１　駆動モータ
１４２　ポリゴンミラー
１４３　反射ミラー
１５１　感光体ドラム
１５２　帯電器
１５３　現像器
１５７　転写極
１５８　分離極
１５９　クリーニング装置
１６０　定着装置
１７１〜１７４　カセット
１７５　記録紙搬送機構
１７６　記録紙排出トレイ
１７７　第１の切替え爪
１８０　第２の切替え爪
１８１　反転ローラー
１８３　後反転搬送路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming method, an image forming apparatus, and an organic photoreceptor used for an electrophotographic copying machine, a printer, and the like.
[0002]
[Prior art]
Electrophotographic photoreceptors have shifted from inorganic photoreceptors such as Se, arsenic, arsenic / Se alloy, CdS, ZnO, etc. to organic photoreceptors having excellent advantages such as pollution and ease of production, and various materials have been used. Organic photoreceptors have been developed.
[0003]
In recent years, a function-separated type photoreceptor in which charge generation and charge transport functions are assigned to different materials has become mainstream, and among them, a stacked organic photoreceptor having a charge generation layer and a charge transport layer laminated (hereinafter simply referred to as a “photoreceptor”). Photosensitive member) is widely used.
[0004]
Turning to the electrophotographic process, the latent image forming method can be changed from analog image forming using a halogen lamp as a light source to digital image forming using an LED or a laser as a light source, because of its ease of image processing and deployment to multifunction devices. The technology is shifting to the image forming of the system.
[0005]
The feature of such a digital copying machine lies in a function of copying electronic data, and therefore, it can be used as a printer. As an image forming method in a digital copying machine, a document image over a plurality of pages is read by an image pickup device such as a CCD, the image data is stored in a memory, and the image data is read out from the memory to be read on an image support (recording paper). And a method of forming an image.
[0006]
Another feature of the digital copying machine is that a so-called electronic RDH (Recycling Document Handler) can be used because double-sided printing is possible electronically (Patent Document 1). Since the electronic RDH enables two-sided printing electronically, unlike the method of printing on both sides with a conventional copying machine, there is no need to stock one side of a recording paper body, and one side of the recording paper is required. And the other side can be printed continuously. That is, the recording paper on which the toner image is formed on the photoreceptor by the digital latent image formation and the toner image is transferred and fixed on one surface is transferred to the transfer and fixing process on the other surface immediately after passing through the fixing process. Conveyed. As a result, when the heat fixing is used, the heated high-temperature recording paper immediately after the fixing is conveyed to the transfer step. In this case, the temperature inside the machine rises due to the heat of the recording paper itself, the temperature of the photoreceptor rises, and problems on images that did not occur in a room temperature environment tend to surface.
[0007]
In digital image formation, reversal development in which an exposed portion is a toner image is generally performed, but black spots specific to the reversal development tend to become apparent when the temperature of the photoconductor becomes high. In general, an organic photoreceptor has a structure in which an intermediate layer, a charge generation layer, and a charge transport layer are laminated on a conductive support. Conventionally, in order to solve this black spot, a technique for preventing injection of charge carriers from a conductive support into the intermediate layer has been developed. For example, an electrophotographic photoreceptor having a configuration in which an intermediate layer is provided between a conductive support and a photosensitive layer, and titanium oxide particles are dispersed in a resin in the intermediate layer is known. Also, a technique of an intermediate layer containing surface-treated titanium oxide is known. For example, titanium oxide surface-treated with iron oxide or tungsten oxide (Patent Document 2), titanium oxide surface-treated with an amino group-containing coupling agent (Patent Document 3), titanium oxide surface-treated with an organosilicon compound ( Patent Literature 4), an intermediate layer using dendritic titanium oxide (Patent Literature 6) surface-treated with titanium oxide (Patent Literature 5) surface-treated with methylhydrogenpolysiloxane, or a metal oxide or an organic compound. Organic photoreceptors having the same have been proposed.
[0008]
However, even with these technologies, in severe environments such as high temperature and high humidity, the prevention of black spots is still insufficient, or the residual potential increases due to repeated use, and the exposure portion potential increases. There is a problem that the image density cannot be sufficiently obtained.
[0009]
Further, in a high-temperature and high-humidity environment, the insulating property of the intermediate layer is increased to prevent free carriers from the conductive support to the photosensitive layer, and the number of black dots is reduced. Has been found that image defects such as "." This white drop refers to a dot or linear image defect that is not developed into a halftone or black solid image of reversal development. This phenomenon is caused by the fact that the charge is not lost in the image exposure portion when forming a latent image on the organic photoreceptor. It is considered that a minute portion is generated, which is considered to be a phenomenon opposite to the above black spot. As described above, in the image forming apparatus using the organic photoreceptor, contradictory image defects such as black spots on a white background and white spots on a black background or a halftone occur, and the organic photoreceptor that has resolved both image defects Development is becoming necessary.
[0010]
In digital image formation, not only copying but also an original image are frequently used, and digital electrophotographic image formation tends to require higher image quality.
[0011]
As one of the techniques for improving image quality, an image forming method using a polymerized toner has been proposed (Patent Document 7). Polymerized toner has a spherical toner shape, which increases the adhesion of the toner to the photoreceptor, causing problems such as a decrease in transferability of the toner from the photoreceptor to recording paper and a decrease in cleaning performance. Cheap. When the transferability and the cleaning property are reduced, not only the image density is reduced, but also image defects such as the above-mentioned “white spots” tend to occur.
[0012]
The present inventors have found that, in order to simultaneously solve the above black spots and white spots, conventional studies focusing on the intermediate layer are insufficient, and the object is a charge generation layer other than the intermediate layer, a charge transport layer. A comprehensive study was conducted including the image forming method including the developer and the developer.
[0013]
[Patent Document 1]
JP 2001-147547 A
[0014]
[Patent Document 2]
JP-A-4-303846
[0015]
[Patent Document 3]
JP-A-9-96916
[0016]
[Patent Document 4]
JP-A-9-258469
[0017]
[Patent Document 5]
JP-A-8-328283
[0018]
[Patent Document 6]
JP-A-11-344826
[0019]
[Patent Document 7]
JP 2000-214629 A
[0020]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems of the prior art, and has been developed in consideration of the above-mentioned problems of the prior art. Another object of the present invention is to provide an image forming method, an image forming apparatus, and an organic photoreceptor capable of providing a high-quality electrophotographic image without causing image defects such as white spots and the like.
[0021]
[Means for Solving the Problems]
As a result of studying the above problem, the present inventors have found that when forming a two-sided image on recording paper using electronic RDH, black spots and white spots, which are likely to occur with an increase in the temperature inside the image forming apparatus, are generated. In order to effectively prevent the occurrence of image defects, in addition to the conventional intermediate layer technology of the organic photoreceptor, it is necessary that the film quality of the charge transport layer be such that it does not deteriorate even under conditions of high temperature and high humidity. And completed the present invention. That is, in the case of an organic photoreceptor having a structure such as a charge generation layer and a charge transport layer on a conductive support, the charge transport layer forming the surface layer is formed by using a charge transport material of a mixture of stereoisomers to form a film. Is not deteriorated and hardly causes deep scratches on the surface, and at the same time, is used in combination with a toner having a good cleaning property and a shape that does not easily damage the photoreceptor. It has been found that it is possible to prevent conflicting image defects, and also to prevent the occurrence of cracks that are likely to occur due to contact friction with a cleaning member or the like. That is, the present invention can achieve the object by adopting any of the following constitutions.
[0022]
1. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image forming method comprising: a charge transport layer containing a transport substance; and a toner used for forming the toner image, wherein a variation coefficient of a shape factor of toner particles is 16% or less.
[0023]
2. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image, characterized in that the toner used for forming the toner image is a charge transport layer containing a transport material, and contains 65% by number or more of toner particles having a shape factor in the range of 1.2 to 1.6. Forming method.
[0024]
3. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image forming method, which is a charge transporting layer containing a transporting substance, wherein the toner used for forming the toner image contains 50% by number or more of toner particles having no corners.
[0025]
4. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. The toner used for forming the toner image, which is a charge transport layer containing a transport material, has a natural logarithm lnD on the horizontal axis, where the particle diameter of the toner particles is D (μm). The relative frequency (m) of the toner particles included in the most frequent class in the histogram showing the number-based particle size distribution divided into a plurality of classes at 23 intervals ₁ ) And the relative frequency (m) of the toner particles contained in the class with the highest frequency next to the mode. ₂ Wherein the sum (M) is 70% or more.
[0026]
5. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image forming method comprising: a charge transport layer containing a transport material; and a toner used for forming the toner image, wherein a coefficient of variation in the number of toner particles is 27% or less.
[0027]
6. 6. The image forming method according to any one of the above items 1 to 5, wherein the content of the most polyisomer component in the stereoisomer mixture is 40 to 90% by mass.
[0028]
7. 7. The image forming method according to any one of items 1 to 6, wherein the organic photoconductor has a charge generation layer and a charge transport layer on a conductive support.
[0029]
8. 8. The image forming method according to claim 1, wherein the toner is a polymerized toner.
[0030]
9. 9. The image forming method according to the item 8, wherein the toner satisfies all the conditions described in the items 1 to 5.
[0031]
10. The image forming method according to any one of Items 1 to 9, wherein the number average particle diameter of the toner is 3.0 to 8.5 μm.
[0032]
11. An image forming apparatus that forms an electrophotographic image using the image forming method according to any one of the above 1 to 10.
[0033]
12. In an organic photoreceptor used for an image forming method of forming a double-sided image by transferring and fixing a toner image formed on the organic photoreceptor to recording paper using electronic RDH, a surface layer of a stereoisomer mixture is used. An organic photoconductor comprising a charge transport layer containing a charge transport material.
[0034]
Hereinafter, the present invention will be described in detail.
The organic photoreceptor (hereinafter, also simply referred to as a photoreceptor) used in the image forming method of the present invention is characterized in that the surface layer is a charge transport layer containing a charge transport material which is a mixture of stereoisomers.
[0035]
That is, by forming the surface layer of the organic photoreceptor with a charge transporting layer using a charge transporting substance having a charge transporting property with a mixture of stereoisomers, image defects such as white spots and black spots are prevented, and charging is performed. An organic photoreceptor having good electrophotographic properties such as properties and sensitivity can be obtained.
[0036]
As described above, the charge transport layer containing the charge transport material of the stereoisomer mixture has good compatibility between the binder and the charge transport material, improves the film quality and electrophotographic properties of the charge transport layer, and It is considered that even when the temperature inside the image forming apparatus rises, the deterioration of the film quality is small, so that good transferability and cleaning property of the toner are maintained.
[0037]
The organic photoreceptor having the above-described characteristics of the present invention is an image forming method in which the internal temperature of the image forming apparatus has a large rise, that is, a first digital photoconductor is formed on the photoreceptor based on image information converted into an electronic image. After forming an electrostatic latent image, converting the electrostatic latent image into a toner image, transferring and fixing the toner image on one side of a recording sheet, immediately transferring the other side without stocking the recording sheet, Conveying to a fixing step, transferring and fixing a toner image based on the second electronic image formed on the organic photoreceptor, an image forming method of forming a double-sided image, that is, using the electronic RDH of the present invention, To be applied to an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper to form a two-sided image (hereinafter, also simply referred to as a process of forming a two-sided image using electronic RDH). Makes the object of the present invention more remarkable. It is possible to volatilization.
[0038]
The maximum component content of the stereoisomer mixture of the present invention is preferably from 40 to 90% by mass. When the content of the maximum component is more than 90% by mass, the dispersibility of the charge transporting substance is deteriorated, the image density is reduced, black spots are easily generated, and cracks are easily generated. On the other hand, if it is less than 40% by mass, the occurrence of white spots increases, the resolution is reduced, and the stability of the electrophotographic characteristics is impaired.
[0039]
The molecular weight of the charge transport material having a stereoisomer structure is preferably 500 or more and 1500 or less. By using such a charge transport material having a large molecular weight, the film quality of the charge transport layer can be improved, and the effect of the present invention described above can be made more remarkable.
[0040]
That is, by using a charge transporting substance having a large molecular weight as described above, which is a mixture of stereoisomers as the charge transporting substance, under high temperature and high humidity, the physical properties of the charge transporting layer are not deteriorated, and black in reversal development is obtained. It is possible to effectively prevent image defects such as spots and white spots, and to achieve an organic photoreceptor having good electrophotographic characteristics.
[0041]
The charge transporting substance of the stereoisomer mixture refers to a charge transporting substance having the same chemical structural formula and having an isomer structure caused by different configurations of atoms or atomic groups in the compound. The charge transport material of the present invention refers to a compound capable of transporting the charge generated by the charge generating material.
[0042]
As the charge transport material of the stereoisomer mixture of the present invention, a bis (arylethenylphenyl) aniline compound or a bis or tributadiene compound is preferable.
[0043]
The bis (arylethenylphenyl) aniline compound of the present invention refers to a group of compounds having two arylethenylphenyl groups having the same chemical structure at the nitrogen atom of aniline, and is preferably represented by the following general formula (1). Compounds having an alkyl group or an alkoxy group at the ortho or para position of the aniline group as in the general formulas (2) to (6) are preferable.
[0044]
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[0045]
In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar ¹ Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar ² Represents a substituted or unsubstituted aromatic group.
[0046]
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[0047]
In the general formula (2), R ¹ , R ² , R ³ , R ⁴ Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar ¹ Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar ² Represents a substituted or unsubstituted aromatic group.
[0048]
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[0049]
In the general formula (3), R ¹ , R ² , R ³ , R ⁴ Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar ¹ Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar ² Represents a substituted or unsubstituted aromatic group.
[0050]
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[0051]
In the general formula (4), R ¹ , R ² , R ³ Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar ¹ Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar ² Represents a substituted or unsubstituted aromatic group.
[0052]
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[0053]
In the general formula (5), R ¹ , R ² , R ³ Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar ¹ Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar ² Represents a substituted or unsubstituted aromatic group.
[0054]
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[0055]
In the general formula (6), R ¹ , R ² Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar ¹ Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar ² Represents a substituted or unsubstituted aromatic group.
[0056]
In addition, Ar in the general formulas (1) to (6) ¹ , Ar ² Is preferably a substituted or unsubstituted aromatic group represented by the following general formula (7).
[0057]
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[0058]
In the general formula (7), R ⁶ ~ R ¹⁷ Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, a halogenated alkyl group having 1 to 4 carbon atoms, a halogen atom or an alkoxy group having 1 to 4 carbon atoms, respectively.
[0059]
Examples of the preferred bis (arylethenylphenyl) aniline-based compound of the present invention are shown below, but the present invention is not limited to the following compound examples. In addition, any of these compounds can have a stereoisomer structure.
[0060]
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[0061]
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[0062]
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[0063]
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[0064]
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[0065]
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[0066]
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[0067]
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[0068]
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[0069]
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[0070]
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[0071]
On the other hand, a bis or tributadiene compound means a compound having two or three butadiene structures symmetrically via a nitrogen atom, and a compound represented by the following general formula (8) or (9) preferable.
[0072]
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[0073]
In the general formula (8), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ May be the same or different, and represents a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, a halogen atom, or an aryl group which may have a substituent. m2 and n2 represent 0 or 1.
[0074]
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[0075]
In the general formula (9), R ₇ ~ R ₁₃ May be the same or different and each represents a hydrogen atom, a lower alkyl group, an alkoxy group, an aryloxy group, a halogen atom or an optionally substituted aryl group, and m3 and n3 each represent 0 or 1.
[0076]
The compound examples of the bis or tributadiene-based compound having a stereoisomer structure are shown below, but the present invention is not limited to the following compound examples.
[0077]
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[0078]
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[0079]
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[0080]
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[0081]
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[0082]
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[0083]
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[0084]
Next, the layer structure of the organic photoreceptor using the above-described charge transport material will be described.
[0085]
The organic photoreceptor of the present invention means an electrophotographic photoreceptor constituted by providing an organic compound with at least one of a charge generation function and a charge transport function, which are indispensable for the configuration of the electrophotographic photoreceptor, and is known. All known organic electrophotographic photoreceptors such as a photoreceptor composed of an organic charge generating substance or an organic charge transporting substance, and a photoreceptor having a charge generating function and a charge transporting function composed of a polymer complex are included.
[0086]
Hereinafter, the constitution of the organic photoreceptor used in the present invention will be described.
Conductive support
The conductive support used for the photoreceptor may be in the form of a sheet or a cylinder, but a cylindrical conductive support is more preferable for designing a compact image forming apparatus.
[0087]
The cylindrical conductive support means a cylindrical support necessary for forming an image endlessly by rotating, and a conductive material having a straightness of 0.1 mm or less and a runout of 0.1 mm or less. Supports are preferred. Exceeding the ranges of straightness and runout makes it difficult to form a good image.
[0088]
As the conductive material, a metal drum such as aluminum or nickel, a plastic drum on which aluminum, tin oxide, indium oxide, or the like is deposited, or a paper or plastic drum coated with a conductive substance can be used. The conductive support has a specific resistance of 10 at room temperature. ³ Ωcm or less is preferable.
[0089]
The conductive support used in the present invention may have a surface on which a sealed alumite film is formed. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, and sulfamic acid. Anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodic oxidation treatment in sulfuric acid, it is preferable that the sulfuric acid concentration is 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is about 20 V. It is not limited. The average thickness of the anodic oxide coating is usually 20 μm or less, particularly preferably 10 μm or less.
[0090]
Middle class
In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.
[0091]
In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (an undercoat layer is also provided) between the support and the photosensitive layer. ) Can be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of the repeating units of these resins. Among these undercoating resins, a polyamide resin is preferable as a resin capable of reducing an increase in residual potential due to repeated use. The thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.
[0092]
The intermediate layer preferably used in the present invention includes an intermediate layer using a curable metal resin obtained by thermally curing an organic metal compound such as a silane coupling agent and a titanium coupling agent. The thickness of the intermediate layer using the curable metal resin is preferably 0.1 to 2 μm.
[0093]
The intermediate layer preferably used in the present invention includes an intermediate layer in which inorganic particles are dispersed in a binder resin. The average particle size of the inorganic particles is preferably from 0.01 to 1 μm. Particularly, an intermediate layer in which surface-treated N-type semiconductor fine particles are dispersed in a binder is preferable. For example, an intermediate layer in which titanium oxide having an average particle diameter of 0.01 to 1 μm, which is surface-treated with a silica / alumina treatment and a silane compound, is dispersed in a polyamide resin may be used. The thickness of such an intermediate layer is preferably from 1 to 20 μm.
[0094]
The N-type semiconductive fine particles are fine particles having a property of using a conductive carrier as an electron. That is, the property of making the conductive carrier an electron means that by including the N-type semiconductor fine particles in an insulating binder, hole injection from the substrate can be efficiently blocked, and electrons from the photosensitive layer can be prevented. On the other hand, it has a property of not exhibiting a blocking property.
[0095]
Here, the method for determining N-type semiconductive particles of the present invention will be described.
An intermediate layer having a thickness of 5 μm (an intermediate layer is formed using a dispersion liquid in which particles are dispersed in a binder resin constituting the intermediate layer by 50% by mass) is formed on the conductive support. The intermediate layer is negatively charged, and the light attenuation characteristics are evaluated. In addition, the light-attenuating characteristics are similarly evaluated by charging to a positive polarity.
[0096]
N-type semiconductive particles are particles that are dispersed in the intermediate layer when the light attenuation when charged negatively is greater than the light attenuation when charged positively in the above evaluation. It is called semiconductive particles.
[0097]
The N-type semiconductor fine particles are specifically titanium oxide (TiO 2). ₂ ), Zinc oxide (ZnO), tin oxide (SnO) ₂ And the like. In the present invention, titanium oxide is particularly preferably used.
[0098]
The average particle size of the N-type semiconductor fine particles used in the present invention is preferably in the range of 10 nm or more and 500 nm or less in number average primary particle size, more preferably 10 nm to 200 nm, and particularly preferably 15 nm to 50 nm. .
[0099]
The intermediate layer using the N-type semiconductive particles having a number average primary particle diameter within the above range can make the dispersion in the layer dense, provide sufficient potential stability, and generate black spots. Has a prevention function.
[0100]
For example, in the case of titanium oxide, the number-average primary particle diameter of the N-type semiconductive fine particles is magnified 10,000 times by transmission electron microscope observation, 100 particles are randomly observed as primary particles, and the ferrite is analyzed by image analysis. It is measured as the number average diameter of the diameter.
[0101]
The shape of the N-type semiconductive fine particles used in the present invention includes dendritic, needle-like and granular shapes, and the N-type semiconductive fine particles having such a shape are, for example, titanium oxide particles having a crystal type. There are anatase type, rutile type, amorphous type and the like, and any crystal type may be used, or two or more crystal types may be mixed and used. Among them, the rutile type is best.
[0102]
One of the hydrophobizing surface treatments performed on the N-type semiconductor fine particles of the present invention is to perform a plurality of surface treatments, and in the plurality of surface treatments, the last surface treatment is a reactive organosilicon compound. Surface treatment. Further, among the plurality of surface treatments, at least one surface treatment is at least one or more surface treatments selected from alumina, silica, and zirconia, and finally, the surface treatment of the reactive organosilicon compound is performed. Is preferred.
[0103]
The alumina treatment, the silica treatment, and the zirconia treatment refer to a treatment for depositing alumina, silica, or zirconia on the surface of the N-type semiconductive fine particles. Also included are hydrates of zirconia. Further, the surface treatment of the reactive organosilicon compound means to use the reactive organosilicon compound in the treatment solution.
[0104]
As described above, the surface treatment of the N-type semiconductor fine particles such as titanium oxide particles is performed at least twice, so that the surface of the N-type semiconductor fine particles is uniformly coated (treated), and the surface treatment is performed. When the N-type semiconductive fine particles are used in the intermediate layer, a good photoreceptor that has good dispersibility of the N-type semiconductive fine particles such as titanium oxide particles in the intermediate layer and does not generate image defects such as black spots can be obtained. You can get it.
[0105]
Photosensitive layer
The photosensitive layer structure of the photoreceptor of the present invention may have a single-layer structure in which a charge generation function and a charge transport function are provided in one layer on the intermediate layer. It is preferable to adopt a configuration separated into a generation layer (CGL) and a charge transport layer (CTL). By adopting a configuration in which functions are separated, an increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoreceptor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the case of a positively charged photoreceptor, the order of the layer configuration is opposite to that in the case of a negatively charged photoreceptor. The most preferable constitution of the photosensitive layer of the present invention is a constitution of a negatively charged photoreceptor having the function separation structure.
[0106]
The configuration of the photosensitive layer of the function-separated negatively charged photoconductor will be described below.
Charge generation layer
The charge generation layer contains a charge generation material (CGM). As other substances, a binder resin and other additives may be contained as necessary.
[0107]
As the charge generation material (CGM), a known charge generation material (CGM) can be used. For example, phthalocyanine pigments, azo pigments, perylene pigments, azurenium pigments and the like can be used. Among these, CGM which can minimize the increase in residual potential due to repeated use has a steric and potential structure capable of forming a stable aggregated structure among a plurality of molecules, and specifically, a phthalocyanine having a specific crystal structure And CGM of a perylene pigment. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu-Kα radiation, and benzimidazole perylene having a maximum peak at a 2θ of 12.4 have almost no deterioration due to repeated use, and remain intact. The potential increase can be reduced.
[0108]
In the case where a binder is used as a dispersion medium of CGM in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is a formal resin, a butyral resin, a silicone resin, a silicone-modified butyral resin, a phenoxy resin, and the like. No. The ratio between the binder resin and the charge generating substance is preferably from 20 to 600 parts by mass per 100 parts by mass of the binder resin. By using these resins, an increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.
[0109]
Charge transport layer
In the present invention, the term “charge transport layer” means a layer having a function of transporting charge carriers (electrons or holes) generated by a charge generating substance or the like.
[0110]
The surface layer of the present invention has a function of a charge transport layer, and contains a binder resin for dispersing a CTM by forming a film by using a stereoisomer mixture as a charge transport material (CTM). As other substances, additives such as antioxidants may be contained as necessary.
[0111]
As the charge transport material (CTM), a known charge transport material can be used in combination with the charge transport material of the above-mentioned stereoisomer mixture. For example, triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, butadiene compounds and the like can be used in combination. These charge transporting substances are usually dissolved in a suitable binder resin to form a layer.
[0112]
Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, polymer organic semiconductors such as poly-N-vinyl carbazole may be used.
[0113]
The most preferred binder for these CTLs is a polycarbonate resin. Polycarbonate resins are most preferred in improving the dispersibility and electrophotographic properties of CTM. In the case of a photoreceptor having a charge transport layer as a surface layer, a polycarbonate which is resistant to mechanical abrasion is preferable, and a polycarbonate having an average molecular weight of 40,000 to 25,000 is preferable. Here, the average molecular weight may be any of a number average molecular weight, a weight average molecular weight, and a viscosity average molecular weight. The ratio between the binder resin and the charge transporting material is preferably from 10 to 200 parts by mass per 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably from 10 to 40 μm.
[0114]
Further, it is preferable that the charge transport layer contains an antioxidant. The antioxidant, the typical one, in the organic photoreceptor or on the autoxidizable substance present on the surface of the organic photoreceptor, light, heat, does not prevent the action of oxygen under conditions such as discharge, It is a substance that has the property of suppressing. Typically, the following compound groups are mentioned.
[0115]
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[0116]
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[0117]
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[0118]
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[0119]
The charge transport layer may have two or more layers. In this case, the charge transport layer on the surface may satisfy the structure of the present invention.
[0120]
Solvents or dispersion media used for forming layers such as an intermediate layer, a photosensitive layer, and a protective layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, and methyl ethyl ketone. , Methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane , Tetrahydrofuran, dioxolan, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. And the like. Although the present invention is not limited to these, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone and the like are preferably used. In addition, these solvents can be used alone or as a mixed solvent of two or more kinds.
[0121]
As a coating method for producing the electrophotographic photoreceptor of the present invention, a coating method such as dip coating, spray coating, circular amount control type coating is used. In order to prevent the film from being dissolved as much as possible and to achieve a uniform coating process, it is preferable to use a coating process method such as spray coating or coating with a circular amount control type (a typical example is a circular slide hopper type). The spray coating is described in detail in, for example, JP-A-3-90250 and JP-A-3-269238, and the circular amount control type coating is described in detail in, for example, JP-A-58-189061. I have.
[0122]
Next, the toner used for forming the toner image of the present invention will be described.
The toner used for forming the toner image of the present invention includes:
{Circle around (1)} The variation coefficient of the shape factor of the toner particles is 16% or less,
(2) The proportion of toner particles having a shape factor of toner particles in the range of 1.2 to 1.6 is 65% by number or more;
(3) The ratio of toner particles having no corners is 50% by number or more,
(4) The number variation coefficient in the number particle size distribution of the toner particles is 27% or less;
{Circle over (5)} When the particle size of the toner particles is D (μm), the natural logarithm lnD is plotted on the horizontal axis, and the horizontal axis is the highest in the histogram showing the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. Relative frequency of toner particles included in the frequent class (m ₁ ) And the relative frequency (m) of the toner particles contained in the class with the highest frequency next to the mode. ₂ ) Is 70% or more.
[0123]
That is, in the present invention, by using a developer containing a toner that satisfies at least one or more of the above conditions (1) to (5) for the photoreceptor having the surface layer, white dropout or black in reversal development can be achieved. It is possible to prevent the occurrence of image defects such as spots, improve the cleaning property, and obtain a good electrophotographic image. Among the above conditions (1) to (5), the conditions (2) and (5) achieve the object of the present invention better than the other conditions (1), (3) and (4). It is important in doing. However, the other conditions (1), (3), and (4) are characteristics that are effective in achieving the object of the present invention. In particular, a toner satisfying all of the above conditions (1) to (5) and a photoreceptor having the surface layer, that is, a photoreceptor having a charge transport layer containing a charge transport material of a stereoisomer mixture as a surface layer. By using them together, it is possible to remarkably reduce image defects in which white spots and black spots are contradictory.
[0124]
Hereinafter, the toners (1) to (5) will be described.
Shape factor of toner (= shape factor of toner particles)
The shape factor of the toner particles is represented by the following equation, and indicates the degree of roundness of the toner particles.
[0125]
Shape factor = ((maximum diameter / 2) ² × π) / projected area
Here, the maximum diameter refers to the width of a particle having a maximum interval between the parallel lines when a projected image of a toner particle on a plane is sandwiched between two parallel lines. The projection area refers to the area of the projected image of the toner particles on the plane.
[0126]
In the present invention, the shape factor can be determined by taking a photograph in which the toner particles are magnified 2,000 times by a scanning electron microscope, and then using SCANNING IMAGE ANALYZER (manufactured by JEOL Ltd.) based on the photograph. It was measured by performing the analysis of. At this time, the shape factor of the present invention was measured using the above formula using 100 toner particles.
[0127]
In the toner of the present invention, the ratio of the toner particles having the shape coefficient in the range of 1.2 to 1.6 is 65% by number or more, and preferably 70% by number or more.
[0128]
In the present invention, the latent image formed on the organic photoreceptor having the surface layer containing the charge transport material of the above-mentioned stereoisomer mixture is obtained by calculating the ratio of the toner particles having a shape factor in the range of 1.2 to 1.6. By developing with a developer containing 65% by number or more, the occurrence of image defects such as white spots and black spots is prevented, the cleaning property is improved, and an electrophotographic image with excellent sharpness is obtained.
[0129]
The method for controlling the shape factor is not particularly limited. For example, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, a method of adding a toner in a solvent that does not dissolve a toner and applying a swirling flow, etc. There is a method in which toner particles having a shape factor of 1.2 to 1.6 are prepared and added to a normal toner so as to fall within the range of the present invention. Further, there is a method in which the overall shape is controlled at the stage of preparing a so-called polymerization toner, and the toner particles whose shape factor is adjusted to 1.2 to 1.6 are similarly added to a normal toner for adjustment.
[0130]
Among the above methods, polymerization toners are preferred in that they are simple as a production method and that they have excellent surface uniformity as compared with pulverized toners. The polymerized toner (also referred to as a polymerized toner) means a toner formed by forming a binder resin for the toner and polymerizing the toner monomer as a raw material of the binder resin and, if necessary, by a subsequent chemical treatment. More specifically, it means a toner obtained through a polymerization reaction such as suspension polymerization and emulsion polymerization, and, if necessary, a subsequent step of fusing particles together.
[0131]
Since the polymerized toner is produced by uniformly dispersing the raw material monomers in an aqueous system and then polymerizing the same, a toner having a uniform particle size distribution and shape can be obtained.
[0132]
Coefficient of variation of shape factor of toner (= coefficient of variation of shape factor of toner particles)
The “coefficient of variation of the shape coefficient” of the toner particles of the present invention is calculated from the following equation.
[0133]
Coefficient of variation = [S / K] × 100 (%)
[Where S ₁ Represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor. ]
The variation coefficient of the shape factor of the toner of the present invention is 16% or less, and preferably 14% or less.
[0134]
In the present invention, the latent image formed on the organic photoreceptor having the surface layer containing the charge transport material of the stereoisomer mixture is developed by a developer using a toner having a variation coefficient of the shape factor of 16% or less. By doing so, the occurrence of image defects such as white spots and black spots is prevented, the cleaning property is improved, and an electrophotographic image with good sharpness is obtained.
[0135]
In order to uniformly control the shape coefficient of the toner and the variation coefficient of the shape coefficient without variation in lots, resin particles (polymer particles) constituting the toner of the present invention are prepared (polymerized), and the resin particles are melted. In the step of controlling the application and shape, an appropriate process end time may be determined while monitoring the characteristics of the toner particles (colored particles) being formed.
[0136]
Monitoring means that a measuring device is incorporated in-line and process conditions are controlled based on the measurement result. That is, for example, in the case of a polymerization toner formed by incorporating measurement of shape and the like in-line and associating or fusing resin particles in an aqueous medium, the shape and particle size are sequentially sampled in a process such as fusing. Is measured, and the reaction is stopped when the desired shape is obtained.
[0137]
Although the monitoring method is not particularly limited, a flow-type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid through. That is, a pump or the like is used from the reaction field to constantly monitor and measure the shape and the like, and stop the reaction when the desired shape and the like are obtained.
[0138]
Coefficient of variation in number of toner (= coefficient of variation in number of toner particles)
The number particle size distribution and the number variation coefficient of the toner particles of the present invention are measured with a Coulter Counter TA- or Coulter Multisizer (manufactured by Coulter Corporation). In the present invention, a Coulter Multisizer was used, and an interface for outputting the particle size distribution (manufactured by Nikkaki) and a personal computer were connected. The particle size distribution and the average particle size were calculated by measuring the volume and the number of toner particles having a size of 2 μm or more using an aperture of 100 μm as the aperture used in the Coulter Multisizer. The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median size in the number particle size distribution. The “number variation coefficient in the number particle size distribution” of the toner particles is calculated from the following equation.
[0139]
Number variation coefficient = [S / Dn] × 100 (%)
[Where S ₂ Represents the standard deviation in the number particle size distribution, and D _n Indicates a number average particle size (μm). ]
The number variation coefficient of the toner particles of the present invention is 27% or less, preferably 25% or less.
[0140]
In the present invention, the latent image formed on the organic photoreceptor having the surface layer containing the charge transport material of the stereoisomer mixture is developed by a developer using a toner having a coefficient of variation of the number of toner particles of 27% or less. By doing so, the occurrence of image defects such as white spots and black spots is prevented, the cleaning property is improved, and an electrophotographic image with good sharpness is obtained.
[0141]
The method for controlling the number variation coefficient in the toner of the present invention is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for further reducing the number variation coefficient. As a method of classifying in the liquid, there is a method in which a centrifugal separator is used to separate and collect toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by controlling the rotation speed.
[0142]
In particular, when a toner is produced by a suspension polymerization method, a classification operation is indispensable in order to reduce the number variation coefficient in the number particle size distribution to 27% or less. In the suspension polymerization method, it is necessary to disperse a polymerizable monomer into oil droplets of a desired size as a toner in an aqueous medium before polymerization. That is, mechanical shearing by a homomixer, a homogenizer, or the like is repeated on a large oil droplet of a polymerizable monomer to reduce the oil droplet to a size of about a toner particle. In the case of the method based on the appropriate shearing, the number and particle size distribution of the obtained oil droplets is wide, and therefore, the particle size distribution of the toner obtained by polymerizing the oil droplets is also wide. For this reason, a classification operation is required.
[0143]
Percentage of toner particles without corners
In the toner particles constituting the toner of the present invention, the ratio of the toner particles having no corners needs to be 50% by number or more, and preferably 70% by number or more.
[0144]
In the toner particles constituting the toner of the present invention, the ratio of the toner particles having no corners is preferably 50% by number or more, more preferably 70% by number or more.
[0145]
In the present invention, a developer using a toner in which the ratio of toner particles having no corners to a latent image formed on an organic photoreceptor having a surface layer containing a charge transport material of the above-mentioned stereoisomer mixture is 50% by number or more Developing by the method prevents the occurrence of image defects such as white spots and black spots, improves the cleaning property, and provides an electrophotographic image with good sharpness.
[0146]
Here, the “toner particles having no corners” refers to toner particles having substantially no protrusions on which electric charges are concentrated or protrusions that are easily worn out by stress. Specifically, the following toner particles Are called toner particles without corners. In other words, as shown in FIG. 2A, when the major axis of the toner particle T is L, a circle C having a radius (L / 10) is in contact with the peripheral line of the toner particle T at one point inside. The case where the circle C does not substantially protrude outside the toner T when the inside is rolled is referred to as “cornerless toner particles”. “Case where the protrusion does not substantially protrude” refers to a case where the protrusion where the protruding circle exists is one or less. Further, the “longer diameter of the toner particle” refers to the width of the particle at which the interval between the parallel lines is the largest when the projected image of the toner particle on the plane is sandwiched between two parallel lines. FIGS. 2B and 2C show projected images of toner particles having corners, respectively.
[0147]
The ratio of the toner particles having no corners was measured as follows. First, a photograph in which toner particles are enlarged by a scanning electron microscope is taken, and further enlarged to obtain a photographic image of 15,000 times. Next, the presence or absence of the corners is measured for this photographic image. This measurement was performed for 100 toner particles.
[0148]
The method for obtaining a toner having no corners is not particularly limited. For example, as described above, as a method of controlling the shape coefficient, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, or a method of dissolving a toner It can be obtained by adding to a solvent which is not used and imparting a swirling flow.
[0149]
In addition, in a polymerization method toner formed by associating or fusing resin particles, the surface of the fused particles has many irregularities at the stage of stopping fusion, and the surface is not smooth. By adjusting the conditions such as the number of rotations of the stirring blade and the stirring time, toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles. For example, when the rotation speed is higher than the glass transition temperature of the resin particles and the number of rotations is higher, the surface becomes smooth and a toner having no corners can be formed.
[0150]
Particle size of toner particles
The toner of the present invention preferably has a number average particle diameter of 3.0 to 8.5 μm. In the case where toner particles are formed by a polymerization method, the particle diameter is determined by the concentration of the coagulant, the amount of the organic solvent added, or the fusing time, and the composition of the polymer itself, in the toner manufacturing method described in detail below. Can be controlled by
[0151]
When the number average particle diameter is 3.0 to 8.5 μm, the transfer efficiency is increased, the halftone image quality is improved, and the image quality of fine lines and dots is improved.
[0152]
When the particle size of the toner particles is D (μm), the toner of the present invention has a natural logarithm lnD on the horizontal axis, and the horizontal axis shows a number-based particle size distribution divided into a plurality of classes at intervals of 0.23. In the histogram, the relative frequency (m) of the toner particles included in the mode ₁ ) And the relative frequency (m) of the toner particles contained in the class with the highest frequency next to the mode. ₂ ) Is 70% or more.
[0153]
In the present invention, the latent image formed on the organic photoreceptor having the surface layer containing the charge transport material of the above-mentioned stereoisomer mixture has a relative frequency (m). ₁ ) And relative frequency (m ₂ ) Is developed with a developer using a toner having a sum (M) of 70% or more, the occurrence of image defects such as white spots and black spots is prevented, the cleaning property is improved, and the sharpness is good. An electrophotographic image can be obtained.
[0154]
In the present invention, the histogram showing the number-based particle size distribution includes a natural logarithm lnD (D: particle size of individual toner particles) at intervals of 0.23 and a plurality of classes (0 to 0.23: 0.23 to 0.23). 0.46: 0.46 to 0.69: 0.69 to 0.92: 0.92 to 1.15: 1.15 to 1.38: 1.38 to 1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76...). The histogram is prepared by transferring particle size data of a sample measured by a Coulter Multisizer to a computer via an I / O unit under the following conditions, and creating the data by a particle size distribution analysis program in the computer. is there.
〔Measurement condition〕
(1) Aperture: 100 μm
(2) Sample preparation method: An appropriate amount of a surfactant (neutral detergent) is added to 50 to 100 ml of an electrolytic solution [ISOTON R-11 (manufactured by Coulter Scientific Japan)], and the mixture is stirred. Add. This system is prepared by subjecting it to a dispersion treatment with an ultrasonic disperser for one minute.
[0155]
Manufacturing method of toner
The toner of the present invention is preferably a polymerized toner obtained by polymerizing at least a polymerizable monomer in an aqueous medium, and a polymerized toner obtained by associating at least resin particles in an aqueous medium. Is preferred. Hereinafter, a method for producing the polymerized toner (hereinafter, also simply referred to as toner) of the present invention will be described in detail.
[0156]
The polymerized toner of the present invention is obtained by emulsion polymerization of monomers in a suspension polymerization method or in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added to form fine polymer particles (resin particles). It can be prepared by a method in which the resin particles are prepared, and thereafter, an organic solvent, a flocculant, and the like are added to associate the resin particles. Here, “association” means that a plurality of the resin particles are fused together, and also includes a case where the resin particles are fused with other particles (for example, colorant particles).
[0157]
In the present invention, the term “polymerized toner” means a toner whose toner binder resin is formed and whose toner shape is formed by polymerization of the raw material monomer of the binder resin and, if necessary, by subsequent chemical treatment. More specifically, it means a toner formed through a polymerization reaction such as suspension polymerization or emulsion polymerization and, if necessary, a step of fusing particles together.
[0158]
If an example of a method for producing the polymerized toner of the present invention is shown, a coloring agent and a releasing agent, if necessary, a charge control agent, various constituent materials such as a polymerization initiator are added to the polymerizable monomer, Various constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which the various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer into oil droplets of a desired size as a toner by using a homomixer, a homogenizer, or the like. Thereafter, the stirring mechanism is moved to a reaction device (stirring device), which is a stirring blade described later, and heated to cause the polymerization reaction to proceed. After completion of the reaction, the toner of the present invention is prepared by removing the dispersion stabilizer, filtering, washing and drying.
[0159]
The “aqueous medium” in the present invention refers to a medium containing at least 50% by mass of water.
[0160]
Further, as a method of producing the polymerized toner of the present invention, a method of preparing by associating or fusing resin particles in an aqueous medium can also be mentioned. Although this method is not particularly limited, for example, the methods described in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904 can be exemplified. That is, a method of associating a plurality of resin particles and dispersed particles of a constituent material such as a colorant, or a fine particle composed of a resin and a colorant, particularly, after dispersing these in water using an emulsifier, the critical aggregation concentration At the same time as adding the above coagulant and salting out, the formed polymer itself is heated and fused at a temperature equal to or higher than the glass transition temperature to gradually grow the particle size while forming fused particles, and the desired particle size. At this point, a large amount of water was added to stop the growth of the particle size, and the surface of the particles was smoothed with heating and stirring to control the shape. The toner of the invention can be formed. Here, a solvent that is infinitely soluble in water may be added simultaneously with the coagulant.
[0161]
Those used as polymerizable monomers constituting the resin include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decyl Styrene, styrene such as pn-dodecylstyrene or a styrene derivative, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate; 2-ethylhexyl methacrylate, stearyl methacrylate, Methacrylate derivatives such as lauryl acrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Acrylates such as isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, olefins such as ethylene, propylene and isobutylene, vinyl chloride, vinylidene chloride, Halogen vinyls such as vinyl bromide, vinyl fluoride, and vinylidene fluoride; vinyl esters such as vinyl propionate, vinyl acetate, and vinyl benzoate; vinyl methyl ether; vinyl ethyl ether Vinyl ethers such as ter, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine and the like. There are acrylic compounds or methacrylic acid derivatives such as vinyl compounds, acrylonitrile, methacrylonitrile, and acrylamide. These vinyl monomers can be used alone or in combination.
[0162]
Further, it is more preferable to use a combination of those having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, those having a substituent such as a carboxyl group, a sulfonic acid group, or a phosphoric acid group as a constituent group of a monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid. Acid, monoalkyl maleate, monoalkyl itaconic acid, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy Propyl methacrylate and the like.
[0163]
Furthermore, polyfunctional such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. A resin having a crosslinked structure can be obtained by using a hydrophilic vinyl.
[0164]
These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. Examples of the oil-soluble polymerization initiator include 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, and 1,1'-azobis (cyclohexane-1-carbo). Azo or diazo polymerization initiators such as nitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4- t-butylperoxycyclohexyl) propane, tris The (t-butylperoxy) triazine peroxide polymerization initiator or a peroxide, such as and the like polymeric initiator having a side chain.
[0165]
When the emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.
[0166]
Dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate , Bentonite, silica, alumina and the like. Further, a surfactant generally used as a surfactant such as polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzenesulfonate, an ethylene oxide adduct, and higher alcohol sodium sulfate can be used as a dispersion stabilizer.
[0167]
As the resin excellent in the present invention, a resin having a glass transition point of 20 to 90 ° C is preferable, and a resin having a softening point of 80 to 220 ° C is preferable. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Further, these resins preferably have a number average molecular weight (Mn) of 1,000 to 100,000 and a weight average molecular weight (Mw) of 2,000 to 1,000,000 as measured by gel permeation chromatography. Further, the molecular weight distribution is preferably such that Mw / Mn is 1.5 to 100, particularly 1.8 to 70.
[0168]
The flocculant used when associating the resin particles in an aqueous medium is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, a salt of an alkali metal such as sodium, potassium, and lithium, and as a divalent metal, for example, a salt of an alkaline earth metal such as calcium and magnesium, or a divalent metal such as manganese or copper And salts of trivalent metals such as iron and aluminum. Specific examples of the salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Can be mentioned. These may be used in combination.
[0169]
It is preferable that these coagulants are added at a critical coagulation concentration or higher. The critical aggregation concentration is an index relating to the stability of the aqueous dispersion, and indicates the concentration at which aggregation occurs when a coagulant is added. This critical aggregation concentration changes greatly depending on the emulsified component and the dispersant itself. For example, it is described in “Polymer Chemistry 17, 601 (1960) edited by The Society of Polymer Science, Japan” by Seizo Okamura et al., And a detailed critical aggregation concentration can be obtained. As another method, a desired salt is added to the target particle dispersion at a different concentration, and the ζ (zeta) potential of the dispersion is measured. The salt concentration at which this value changes is defined as the critical aggregation concentration. You can also ask.
[0170]
The amount of the coagulant of the present invention may be at least the critical coagulation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical coagulation concentration.
[0171]
As the “solvent that is infinitely soluble in water” used together with the coagulant, a solvent that does not dissolve the formed resin is selected. Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. Particularly, ethanol, propanol and isopropanol are preferred.
[0172]
The addition amount of the solvent infinitely soluble in water is preferably 1 to 100% by volume based on the polymer-containing dispersion to which the flocculant has been added.
[0173]
In order to homogenize the particle shape, it is preferable to prepare a colored particle, and after the filtration, it is preferable to fluidly dry a slurry in which 10% by mass or more of water exists relative to the particle. Those having a polar group therein are preferred. This is considered to be because the existing water exerts an effect of slightly swelling the polymer in which the polar group is present, so that the shape is particularly easily uniformized.
[0174]
Although the toner of the present invention contains at least a resin and a colorant, it may contain a releasing agent or a charge control agent as a fixability improving agent, if necessary. Further, an external additive composed of inorganic fine particles, organic fine particles, and the like may be added to the toner particles containing the resin and the colorant as main components.
[0175]
As the colorant used in the toner of the present invention, carbon black, a magnetic substance, a dye, a pigment, and the like can be arbitrarily used. Examples of the carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. used. As the magnetic material, ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys which do not contain ferromagnetic metals but show ferromagnetism by heat treatment, For example, alloys of a type called a Heusler alloy such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide, and the like can be used.
[0176]
As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc., and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31, 43 and C.I. I. Pigment Yellow 14, 17, 17, 93, 94, 138, C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15: 3, 60 and the like, and mixtures thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.
[0177]
As a method of adding a colorant, a method of adding a polymer particle prepared by an emulsion polymerization method at the stage of aggregating by adding an aggregating agent and coloring the polymer, or a process of polymerizing a monomer at the colorant And polymerizing it to obtain colored particles. When the colorant is added at the stage of preparing the polymer, it is preferable to use the colorant after treating the surface with a coupling agent or the like so as not to inhibit the radical polymerizability.
[0178]
Further, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene, or the like may be added as a fixing property improving agent.
[0179]
Similarly, various known charge control agents, which can be dispersed in water, can be used. Specific examples include a nigrosine dye, a metal salt of naphthenic acid or a higher fatty acid, an alkoxylated amine, a quaternary ammonium salt compound, an azo metal complex, a metal salt of salicylic acid or a metal complex thereof.
[0180]
The particles of the charge control agent and the fixability improving agent preferably have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.
[0181]
In the toner of the present invention, more effects can be exhibited by adding and using fine particles such as inorganic fine particles and organic fine particles as an external additive. The reason for this is presumed that burying and desorption of the external additive can be effectively suppressed, so that the effect is remarkable.
[0182]
As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania, and alumina. Further, it is preferable that these inorganic fine particles have been subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent, or the like. The degree of the hydrophobic treatment is not particularly limited, but a methanol wettability of 40 to 95 is preferable. Methanol wettability is to evaluate the wettability to methanol. In this method, 0.2 g of the inorganic fine particles to be measured is weighed and added to 50 ml of distilled water placed in a 200 ml beaker. Methanol is slowly dropped from a buret whose tip is immersed in the liquid until the entire inorganic fine particles are wet with slow stirring. When the amount of methanol required to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following equation.
[0183]
Degree of hydrophobicity = (a / (a + 50)) × 100
The amount of the external additive added is 0.1 to 5.0% by mass, and preferably 0.5 to 4.0% by mass in the toner. Various external additives may be used in combination.
[0184]
In the case of a suspension polymerization method toner in which a toner component such as a colorant is dispersed or dissolved in a so-called polymerizable monomer is suspended in an aqueous medium and then polymerized to obtain a toner, a reaction vessel for performing a polymerization reaction is used. By controlling the flow of the medium in the above, the shape of the toner particles can be controlled. That is, when many toner particles having a shape factor of 1.2 or more are to be formed, the flow of the medium in the reaction vessel is made turbulent, and the polymerization proceeds to be present in the aqueous medium in a suspended state. When the oil droplets are gradually polymerized, the oil droplets become soft particles.When the oil droplets collide, the particles collide to promote coalescence of the particles, resulting in particles with irregular shapes. . When forming substantially spherical toner particles having a shape factor smaller than 1.2, substantially spherical particles can be obtained by using a medium flow in the reaction vessel as a laminar flow to avoid collision of the particles. By this method, the distribution of the toner shape can be controlled within the scope of the present invention.
[0185]
Next, a reaction apparatus preferably used for producing a polymerized toner will be described. 3 and 4 are a perspective view and a sectional view, respectively, showing an example of the polymerization toner reaction device. In the reaction apparatus shown in FIGS. 3 and 4, a rotating shaft 3j is vertically provided at a central portion in a vertical cylindrical stirring tank 2j having a heat exchange jacket 1j mounted on an outer peripheral portion thereof, and stirring is performed on the rotating shaft 3j. A lower stirring blade 40j disposed close to the bottom surface of the tank 2j and a stirring blade 50j disposed higher in the tank are provided. The upper-stage stirring blade 50j is disposed at an intersection angle α that precedes in the rotation direction with respect to the lower-stage stirring blade 40j. When producing the toner of the present invention, the intersection angle α is preferably less than 90 degrees (°). The lower limit of the intersection angle α is not particularly limited, but is preferably about 5 ° or more, and more preferably 10 ° or more. When a three-stage stirring blade is provided, it is preferable that the intersection angle α between adjacent stirring blades is less than 90 degrees.
[0186]
With such a configuration, the medium is first stirred by the stirring blades 50j disposed in the upper stage, and a flow to the lower side is formed. Subsequently, the flow formed by the upper stirring blade 50j is further accelerated downward by the stirring blades 40j disposed at the lower stage, and a downward flow is separately formed by the stirring blades 50j themselves, so that the overall flow is reduced. It is presumed that it accelerates and proceeds. As a result, it is presumed that a basin having a large shear stress formed as a turbulent flow is formed, so that the shape of the obtained toner particles can be controlled.
[0187]
In FIGS. 3 and 4, arrows indicate the direction of rotation, 7j is an upper material inlet, 8j is a lower material inlet, and 9j is a turbulent flow forming member for enabling agitation.
[0188]
Here, the shape of the stirring blade is not particularly limited, but may be a rectangular plate, a notch in a part of the blade, a hole having one or more middle holes in the center, a so-called slit, or the like. Can be used. These specific examples are described in FIG. The stirring blade 5a shown in FIG. 5 (a) has no center hole, the stirring blade 5b shown in FIG. 5 (b) has a large center hole 6b in the center, and the stirring blade 5c shown in FIG. 5 (c). In the figure, the stirring blade 5d shown in FIG. 3D has a vertically long middle hole 6d (slit). Further, in the case where a three-stage stirring blade is provided, even if the middle hole formed in the upper stirring blade and the middle hole formed in the lower stirring blade are different, they are the same. There may be.
[0189]
The gap between the upper and lower stirring blades having the above configuration is not particularly limited, but it is preferable that at least a gap is provided between the stirring blades. Although the reason is not clear, it is considered that the stirring efficiency is improved because the flow of the medium is formed through the gap. However, the gap has a width of 0.5 to 50%, preferably 1 to 30% with respect to the liquid level in the stationary state.
[0190]
Further, the size of the stirring blade is not particularly limited, but the sum of the heights of all the stirring blades is 50% to 100%, preferably 60% to 95% of the liquid level height in the stationary state. is there.
[0191]
On the other hand, in a polymerization method toner in which resin particles are associated or fused in an aqueous medium, by controlling the flow and temperature distribution of the medium in the reaction vessel at the fusion step, and further in the shape control step after fusion. By controlling the heating temperature, the number of rotations for stirring, and the time, the shape distribution and shape of the entire toner can be arbitrarily changed.
[0192]
That is, in the polymerization method toner in which the resin particles are associated or fused, the flow in the reaction device is made laminar, and the fusing step and the agitation tank are performed by using a stirring blade and a stirring tank capable of making the internal temperature distribution uniform. By controlling the temperature, the number of rotations, and the time in the shape control step, it is possible to form a toner having a desired shape factor and a uniform shape distribution. The reason for this is that when fusion is performed in a place where a laminar flow is formed, strong stress is not applied to the particles that are undergoing aggregation and fusion (association or aggregated particles) and the flow is accelerated in a laminar flow. It is presumed that as a result of the uniform temperature distribution in the stirring tank, the shape distribution of the fused particles becomes uniform. Further, the fused particles gradually become spherical by heating and stirring in the subsequent shape control step, and the shape of the toner particles can be arbitrarily controlled.
[0193]
The same stirring tank as used in the above-mentioned suspension polymerization method can be used as a stirring tank for producing a polymerization method toner for associating or fusing resin particles. In this case, it is necessary not to provide an obstacle such as a baffle plate that forms a turbulent flow in the stirring tank.
[0194]
The shape of the stirring blade is not particularly limited as long as it forms a laminar flow and does not form a turbulent flow. However, the shape of the stirring blade is formed by a continuous surface such as a square plate shown in FIG. Is preferable, and may have a curved surface.
[0195]
The toner of the present invention may be, for example, a case where a magnetic substance is contained and used as a one-component magnetic toner, a case where it is used as a two-component developer by mixing with a so-called carrier, or a case where a non-magnetic toner is used alone. Any of these can be suitably used, but in the present invention, it is preferable to use it as a two-component developer used by mixing with a carrier.
[0196]
Next, the image forming apparatus of the present invention will be described.
FIG. 1 shows an image which can be suitably used in an image forming method of forming a double-sided image by transferring and fixing a toner image formed on an organic photoreceptor to recording paper using the electronic RDH of the present invention. FIG. 1 is a diagram illustrating an entire configuration of a forming apparatus (digital copying machine).
[0197]
1, the digital copying machine includes an image reading unit A, an image processing unit B, an image storage unit C, and an image forming unit D. The image reading unit A corresponds to a reading unit, the image processing unit B corresponds to an image processing unit, the image storage unit C corresponds to an image data storage unit, and the image forming unit D corresponds to an image forming unit.
[0198]
In the image reading unit A, an original 121 is described on an original platen glass (hereinafter abbreviated as platen glass) 122 and is illuminated by a halogen light source 123 provided on a carriage that moves on a guide rail (not shown). A movable mirror unit 126 provided with a pair of mirrors 124 and 125 moves on the slide rail, and in combination with a mirror 127 provided on the carriage, reflected light from the document 121 on the platen glass 122, The optical image is led to the lens reading unit 128. The lens reading unit 128 includes an imaging lens 129 and a CCD line sensor 130. The optical image corresponding to the image on the document 121 reflected and transmitted by the mirrors 124, 125, and 127 is converged by the imaging lens 129 and formed on the light receiving surface of the CCD line sensor 130. Thus, the optical images on the lines are sequentially photoelectrically converted into electric signals.
[0199]
When a copy button provided on the operation unit 28 is pressed, a halogen light source 123 driven in conjunction with a motor (not shown), a carriage provided with a mirror 127, and a movable mirror unit 126 move to move one page. The image information of the document is read by the CCD line sensor 130. The originals 121 placed one by one on the platen glass 122 are sequentially read as described above and output as image data for one page.
[0200]
The image signal of the original image read by the image reading unit A, that is, image data, after being subjected to various image processing such as density conversion, filter processing, scaling processing, and γ correction in an image processing unit B described later, The image is output to the image forming unit D via the image storage unit C. The image forming unit D forms an image on a recording sheet according to input image data by a laser printer using electrophotography.
[0201]
That is, the image forming unit D modulates a laser beam generated by a semiconductor laser (not shown) based on an image signal. The laser beam is rotationally scanned by a polygon mirror 142 rotated by a drive motor 141, passes through an fθ lens (not shown), bends an optical path by a reflection mirror 143, and is projected onto the surface of the photosensitive drum 151 to be uniformly charged. An electrostatic latent image is formed on the photoreceptor drum 151 thus formed. Here, the photoconductor drum 151 is preferably made of an organic photoconductor from the viewpoint of environmental protection and pollution-free.
[0202]
Further, a charger (also a charging step) 152 for uniformly charging the photosensitive drum 151, a developing device (also a developing step) 153, a transfer pole (also a transfer step) 157, a separation pole (a separation step) 158), a cleaning device (also a cleaning process) 159, and a fixing device (also a fixing process) 160, and the electrostatic latent image formed on the photosensitive drum 151 is developed by the developing device 153. Then, the toner image is transferred onto a recording sheet and fixed, so that a copy image of the original is obtained.
[0203]
The recording paper is stocked in cassettes 171 to 174 for each size, and the recording paper is taken out from the corresponding cassette 171 to 174 according to the instruction of the recording paper size, and the recording paper includes a plurality of transport rollers and a transport belt. The paper is supplied to the photosensitive drum 151 by the paper transport mechanism 175.
[0204]
In the case of single-sided copying, a toner image is sequentially transferred and fixed onto one side of recording paper sequentially taken out of the cassette, and is discharged onto a recording paper discharge tray 176.
[0205]
In the case of double-sided copying, the recording paper fed with the toner image transferred and fixed on one side is fed to the first switching claw 177 (the position indicated by the broken line in the figure) disposed immediately after the fixing device 160 in the recording paper transport path. , And is guided to a duplex copying unit (hereinafter, abbreviated as ADU). The second switching claw 180 (the position indicated by the broken line in the drawing) in the recording paper transport path allows the recording paper to pass rightward and then reverses the reverse roller 181 and simultaneously sets the second switching claw to the position indicated by the solid line in the drawing. Switch to. As a result, the recording paper is turned upside down and then fed to the photosensitive drum 151 via the reverse conveyance path 183 in the same manner as the paper feeding from the cassettes 171 and 172. The image data on the back side of the document is read out from the image storage unit C, and an image is sequentially formed on the back side of the recording paper to obtain a double-sided copy.
[0206]
Further, in the digital copying machine shown in FIG. 1, an automatic document feeder 81 for automatically transporting the read document 121 onto the platen glass 122 is provided in the image reading section A. The automatic document feeder 81 sets a plurality of documents to be read on a document set table 82 and presses a copy button. When the copy button is pressed, each page of the document is sequentially fed, and a predetermined position on the platen glass 122 is sequentially placed. The document 121 that has been read is removed from the platen glass 122 and discharged onto the document discharge tray 94.
[0207]
Further, as described above, the automatic document feeder 81 sequentially sends out and reads the one-sided document 121 on which an image is written on one side of the document, and also takes out one double-sided document and sends it to the platen glass 122 to send the one-sided image. When reading is completed, the document is moved in the reverse direction, the direction is changed by a reversing section including a reversing guide and a reversing roller, and the document is turned over and sent to a predetermined position on the platen glass 122 so that image information on the back surface of the document can be read. Have been.
[0208]
For the automatic conveyance of the original as described above, the paper feed roller 83 which feeds the originals on the original set table 82 one by one, the driving roller 84 and the driven roller 92, and the winding by the driving roller 84 and the driven roller 92. A belt 86 that is driven to rotate, a reversing unit including a guide plate 89, a reversing roller 90, and a switching guide 88 that is driven by a solenoid (not shown), and a document discharge roller 87 are provided.
[0209]
When such an automatic document feeder is used, the document 121 can be automatically sent to a predetermined reading position on the platen glass 122 automatically and output as a read image signal regardless of whether it is a double-sided document or a single-sided document.
[0210]
In the present invention, the image forming method of forming a double-sided image on a recording sheet by using an electronic RDH (Recirculating Document Handler) is different from the conventional method of forming an image on both sides by an analog copying machine, and the image is formed on one side of the recording sheet. There is no need to stock the formed image, and the image is immediately formed continuously on the other surface of the recording paper to form a double-sided image. That is, based on image information converted into an electronic image, a first digital electrostatic latent image is formed on a photoreceptor, and the electrostatic latent image is formed into a toner image. After the transfer / fixing, the recording paper is immediately conveyed to the transfer / fixing step on the other side without stocking, and the toner image based on the second electronic image formed on the organic photoconductor is transferred / fixed. Means that a double-sided image is formed.
[0211]
Further, in the above-described image forming apparatus, a detachable process cartridge in which at least one of the photoconductor, the developing device, the charging device, the transfer electrode, the separation electrode, and the cleaning device is integrated may be formed.
[0212]
The organic photoreceptor, image forming method, image forming apparatus, and process cartridge of the present invention are generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers. It can be widely applied to such devices as display, recording, light printing, plate making, and facsimile.
[0213]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto. “Parts” in the text indicates parts by mass.
[0214]
Example 1
Synthesis Example 1 (Synthesis Example of Exemplified Compound T20)
[0215]
Embedded image

[0216]
10 g of the compound represented by the above formula was dissolved in 32 g of phosphorus oxychloride, heated to 50 ° C., and 22 ml of dimethylformamide was added dropwise little by little (heat was raised to 40 to 70 ° C.). The reaction solution was stirred for 15 hours while controlling the temperature around 90 ° C. After allowing to cool to 40 ° C, excess phosphorus oxychloride is sufficiently hydrolyzed, and the precipitated crystals are separated by filtration, suspended and washed with water, and washed repeatedly until the washing liquid becomes neutral. 9.25 g (77%) of the represented bisformyl compound were obtained.
[0219]
Embedded image

[0218]
2 g of the bisformyl compound obtained above and 4.3 g of a phosphonate compound represented by the following structural formula were dissolved in 20 ml of dimethylformamide. While maintaining the reaction solution at about 20 ° C., 1.0 g of sodium methoxide was added little by little (exothermic). After stirring for 4 hours, 30 ml of water was added and purification was performed by a conventional method to obtain 3.3 g (81%) of yellow crystals. When this compound was subjected to elemental analysis and mass spectrometry, the results were as shown in Table 1 below, and it was confirmed that the compound was the exemplary compound T20.
[0219]
Embedded image

[0220]
Elemental analysis (C ₅₃ H ₄₉ N)
[0221]
[Table 1]

[0222]
Mass spectrometry (C ₅₃ H ₄₉ N)
Mw (calculated value) = 699
Mw ⁺ (Actual value) = 699
The compound of T20 obtained by the above synthesis is designated as T20-1. This T20-1 was measured by the following liquid chromatography (HPCL) and found to have a cis-cis / cis-trans / trans-trans mixture ratio of 1.1 / 2.2 / 1.0. The structural formulas of T20cis-cis, T20trans-trans, and T20cis-trans are shown below.
[0223]
Liquid chromatography measurement conditions
Measuring machine: Shimadzu LC6A (manufactured by Shimadzu Corporation)
Column: CLC-SIL (manufactured by Shimadzu Corporation)
Detection wavelength: 290 nm
Mobile phase: n-hexane / dioxane = 10 to 500/1
Mobile phase flow rate: about 1 ml / min
Sample (T20) solvent: n-hexane / dioxane = 10/1
Sample (T20): 3 mg / solvent 10 ml
[0224]
Embedded image

[0225]
A compound in which T20-1 obtained above was separated into a cis-cis form, a cis-trans form, and a trans-trans form using liquid chromatography was also obtained. The cis-cis T20 is T20c-c, the cis-trans T20 is T20ct, and the trans-trans T20 is T20t-t. T20-1 and T20c-c, T20c-t, and T20t-t were used and the mixing ratio was changed. As shown in Table 2, T20 having a mixing ratio of cis-cis / cis-trans / trans-trans -2 to T20-8 were prepared.
[0226]
Production of photoconductor 1

Titanium oxide, polyamide resin, and methanol were added to the same container and dispersed using an ultrasonic homogenizer to prepare a coating solution for the intermediate layer. This coating solution was applied by dip coating on a cylindrical aluminum substrate, and cured by heating at 110 ° C. for 1 hour to provide an intermediate layer with a dry film thickness of 4 μm.
[0227]

And mixed with a sand mill for 10 hours to prepare a charge generation layer coating solution. This coating solution was applied on the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.2 μm.
[0228]

Were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied on the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 24 μm.
[0229]
Preparation of photoreceptors 2 to 9
The same as the photoconductor 1 except that the charge transport material (T20-1) used in the photoconductor 1 was changed to T20-2 to T20-8 and T20t-t, and the mixing ratio of the isomers was changed as shown in Table 2. Photoconductors 2 to 9 were prepared.
[0230]
[Table 2]

[0231]
Production of toner and developer
(Toner Production Example 1: Example of Emulsion Polymerization Association Method)
0.90 kg of sodium n-dodecyl sulfate and 10.0 liters of pure water were added and dissolved by stirring. 1.20 kg of Regal 330R (carbon black manufactured by Cabot Corporation) was gradually added to this solution, and the mixture was stirred well for 1 hour, and then continuously dispersed for 20 hours using a sand grinder (medium type disperser). This is referred to as “colorant dispersion liquid 1”.
[0232]
Further, a solution composed of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 liters of ion-exchanged water is referred to as “anionic surfactant solution A”.
[0233]
A solution consisting of 0.014 kg of a 10 mol adduct of nonylphenol polyethylene oxide and 4.0 liters of ion-exchanged water is referred to as “nonionic surfactant solution B”.
[0234]
A solution prepared by dissolving 223.8 g of potassium persulfate in 12.0 liters of ion-exchanged water is referred to as “initiator solution C”.
[0235]
A WAX emulsion (polypropylene emulsion having a number average molecular weight of 3,000: a number average primary particle diameter of 120 nm / solid concentration = 29.) Was placed in a 100-liter GL (glass lining) reactor equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device. (9%) 3.41 kg, the whole amount of “anionic surfactant solution A” and the whole amount of “nonionic surfactant solution B” were added, and stirring was started. Next, 44.0 liters of ion-exchanged water was added.
[0236]
Heating was started, and when the liquid temperature reached 75 ° C., the entire amount of “initiator solution C” was added dropwise. Thereafter, 12.1 kg of styrene, 2.88 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 548 g of t-dodecyl mercaptan were added dropwise while controlling the liquid temperature to 75 ° C. ± 1 ° C. After completion of the dropwise addition, the liquid temperature was raised to 80 ° C. ± 1 ° C., and the mixture was heated and stirred for 6 hours. Next, the liquid temperature was cooled to 40 ° C. or lower, stirring was stopped, and the mixture was filtered with a pole filter to obtain a latex. This is designated as "latex-A".
[0237]
The glass transition temperature of the resin particles in Latex-A was 57 ° C, the softening point was 121 ° C, the molecular weight distribution was weight average molecular weight = 127,000, and the weight average particle size was 120 nm.
[0238]
A solution obtained by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 liters of ion-exchanged pure water is referred to as “anionic surfactant solution D”.
[0239]
Further, a solution obtained by dissolving 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct in 4.0 liters of ion-exchanged water is referred to as “nonionic surfactant solution E”.
[0240]
A solution prepared by dissolving 200.7 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) in 12.0 liters of ion-exchanged water is referred to as “initiator solution F”.
[0241]
A WAX emulsion (polypropylene emulsion with a number average molecular weight of 3000: number average primary particle diameter = 120 nm / solids concentration 29.9%) was placed in a 100-liter GL reactor equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb baffle. 3.41 kg, the entire amount of “anionic surfactant solution D” and the entire amount of “nonionic surfactant solution E” were added, and stirring was started.
[0242]
Next, 44.0 liters of ion-exchanged water was charged. Heating was started, and when the liquid temperature reached 70 ° C., “Initiator solution F” was added. Then, a solution prepared by previously mixing 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 9.02 g of t-dodecylmercaptan was added dropwise. After completion of the dropwise addition, the mixture was heated and stirred for 6 hours while controlling the liquid temperature to 72 ° C. ± 2 ° C. Further, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature was cooled to 40 ° C. or lower, and the stirring was stopped. The solution is filtered through a Pall filter, and this filtrate is referred to as “latex-B”.
[0243]
In addition, the glass transition temperature of the resin particles in Latex-B was 58 ° C, the softening point was 132 ° C, the molecular weight distribution was weight average molecular weight = 245,000, and the weight average particle size was 110 nm.
[0244]
A solution obtained by dissolving 5.36 kg of sodium chloride as a salting-out agent in 20.0 liters of ion-exchanged water is referred to as “sodium chloride solution G”.
[0245]
A solution obtained by dissolving 1.00 g of a fluorine-based nonionic surfactant in 1.00 liter of ion-exchanged water is referred to as “nonionic surfactant solution H”.
[0246]
A 100-liter SUS reaction vessel equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a particle size and shape monitoring device (reactor having a configuration shown in FIG. 3 and a cross angle α of 25 °) was prepared as described above. Latex-A = 20.0 kg, latex-B = 5.2 kg, colorant dispersion 1 = 0.4 kg and ion-exchanged water 20.0 kg were stirred. Then, the mixture was heated to 40 ° C., and sodium chloride solution G, 6.00 kg of isopropanol (manufactured by Kanto Kagaku), and nonionic surfactant solution H were added in this order. Then, after standing for 10 minutes, the temperature was raised, the temperature was raised to 85 ° C. in 60 minutes, and the mixture was heated and stirred at 85 ± 2 ° C. for 0.5 to 3 hours, and subjected to salting-out / fusion. Diameter growth (salting out / fusion step). Next, 2.1 liters of pure water was added to stop the particle size growth, and a fused particle dispersion was prepared.
[0247]
The fused particle dispersion liquid prepared above was placed in a 5-liter reaction vessel equipped with a temperature sensor, a cooling pipe, and a particle size and shape monitoring device (reactor having a configuration shown in FIG. 3 and an intersection angle α of 20 °). 5.0 kg was added, and the shape was controlled by heating and stirring at a liquid temperature of 85 ° C. ± 2 ° C. for 0.5 to 15 hours (shape controlling step). Thereafter, the mixture was cooled to 40 ° C. or lower and the stirring was stopped. Next, classification is performed in the liquid by a centrifugal sedimentation method using a centrifugal separator, and the liquid is filtered through a sieve having openings of 45 μm, and the filtrate is used as an associated liquid. Next, non-spherical particles in the form of a wet cake were filtered from the association liquid using a Nutsche. Thereafter, the substrate was washed with ion-exchanged water. The non-spherical particles were dried at a suction air temperature of 60 ° C. using a flash jet drier, and then dried at a temperature of 60 ° C. using a fluidized bed drier. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed with a Henschel mixer to obtain a toner by an emulsion polymerization association method.
[0248]
In the monitoring of the salting-out / fusing step and the shape control step, the number of rotations of the stirring and the heating time are controlled to control the variation coefficient of the shape and the shape factor, and the particle size and the particle size distribution are further classified by submerged classification. The toners 1 to 16 comprising toner particles having the shape characteristics and the particle size distribution characteristics shown in Table 3 were arbitrarily adjusted.
[0249]
[Table 3]

[0250]
(Manufacture of developer)
Developers 1 to 16 for evaluation were produced by mixing 10 parts by mass of each of toners 1 to 16 and 100 parts by mass of a 45 μm ferrite carrier coated with a styrene-methacrylate copolymer.
[0251]
Evaluation
The photoreceptors 1 to 9 and the developers 1 to 16 were combined as shown in Table 4, and a digital copying machine Konica 7075 (Corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, blade cleaning, (A process of forming a double-sided image using a cleaning roller and an electronic RDH). The cleaning performance and the image evaluation were carried out by double-side copying an original image having a character ratio of 7%, a portrait image of a person, a solid white image, and a solid black image, each having a quarter size, on A4 neutral paper. . The copying conditions were evaluated by performing continuous copying of 200,000 sheets in a high-temperature and high-humidity environment (30 ° C., 80% RH), which is considered to be the most severe. However, before the start of copying, the surface of the photoreceptor was dusted with a setting powder, and the photoreceptor and the cleaning blade were blended. The evaluation items and evaluation criteria are shown below.
[0252]
[Table 4]

[0253]
Evaluation items and evaluation criteria
Image density (measured using Macbeth reflection densitometer "RD-918". Measured with relative reflection density assuming that the reflection density of paper is "0". Evaluated both at initial stage and after copying 200,000 sheets)
A: 1.2 or more (good) both in the initial stage and after copying 200,000 sheets
：: 1.0 or more for both initial and after 200,000 copies
×: At least one of the initial stage and after 200,000 copies is less than 1.0
(Practically problematic level)
Fog: determined by solid white image density
Using a reflection densitometer “RD-918” manufactured by Macbeth Co., Ltd., the density of unprinted copy paper (white paper) is measured at 20 locations in absolute image density, and the average value is defined as the blank paper density. Next, absolute image densities were similarly measured at 20 white background portions of the evaluation paper on which an image was formed, and a value obtained by subtracting the white paper density from the average density was evaluated as a fog density.
[0254]
：: 0.005 or less for both initial and after 200,000 copies (good)
：: 0.01 or less both at the initial stage and after 200,000 copies (a level that is practically acceptable)
×: At least one of the initial stage and after 200,000 copies is larger than 0.01 (obviously, there is a practical problem)
Resolution (determined based on the ease of distinguishing character images)
After copying 200,000 sheets, character images of 3 points and 5 points were formed and evaluated according to the following criteria.
[0255]
：: 3 points and 5 points are clear and easily legible (good)
：: 3 points are partially unreadable, 5 points are clear and easily readable
(A level that is practically acceptable)
×: 3 points almost illegible, 5 points partially or completely illegible
Cleanability (10 continuous copies on A3 paper after 100,000 and 200,000 copies have been made, and judgment is made based on whether or not cleaning failure has occurred in the solid white area)
◎: No toner slippage occurred up to 200,000 sheets (good)
：: No toner slippage occurred up to 100,000 sheets (a level that causes no practical problem)
×: toner slippage occurs when less than 100,000 sheets (a level that poses a problem in practical use)
White dropping (after copying 200,000 copies, 100 halftone images were further prepared and evaluated)
The white spots were evaluated by determining the number of white spots having a major axis of 0.4 mm or more per A4 paper, in which the periodicity coincided with the period of the photoconductor.
[0256]
：: Frequency of white spots of 0.4 mm or more: All copied images are 3 copies / A4 or less (good)
：: White spotting frequency of 0.4 mm or more: One or more occurrences of 4 pieces / A4 or more and 19 pieces / A4 or less (a level at which there is no practical problem)
×: White drop of 0.4 mm or more Frequency: 20 pieces / A4 or more one or more sheets
(Practically problematic level)
Black spots (after the above 200,000 copies, 100 more solid white copy images were prepared and evaluated)
Regarding the black spots, the periodicity coincided with the cycle of the photoreceptor, and the number of visible black spots per A4 size was determined.
[0257]
：: Frequency of black spots of 0.4 mm or more: All copied images are 3 copies / A4 or less (good)
：: Frequency of black spots of 0.4 mm or more: 4 pieces / A4 or more and 19 pieces / A4 or less occur at least one sheet (a level that is not a problem in practical use)
×: Black spots of 0.4 mm or more Frequency: 20 pieces / A4 or more one or more
(Practically problematic level)
crack
After the continuous double-sided copying of 200,000 sheets, the power of the Konica 7075 was turned off while the photoconductor was mounted in an environment of 30 ° C. and 80% RH for 2 days. The members around the photoreceptor only stopped operating during this time, that is, the members such as the cleaning blade, the cleaning roller, and the developer conveying member were kept in contact with the photoreceptor. Thereafter, the surface of the photoreceptor was observed to observe the presence or absence of cracks, and an image was formed (detecting whether a streak-like image accompanying the occurrence of cracks appeared on the image).
[0258]
：: No cracks or streak-like image defects occurred (good)
◯: There are fine cracks, but no streak-like image defects are found (no problem in practical use)
×: Cracks have occurred and streak-like image defects have also occurred (in practice, there is a problem)
Other evaluation conditions
In addition, other evaluation conditions using the above Konica 7075 were set to the following conditions.
[0259]
Charging conditions
Charger: Scorotron charger, initial charging potential is -750V
Exposure conditions
A 780 nm semiconductor laser was used as the exposure light source.
Transfer conditions
Transfer pole; corona charging method
Cleaning conditions
A cleaning blade having a hardness of 70 °, a rebound resilience of 65%, a thickness of 2 (mm) and a free length of 9 mm was brought into contact with the cleaning portion by a weight load method so as to have a linear pressure of 18 (N / m) in the counter direction.
[0260]
Cleaning roller: A roller whose surface was covered with a foamable urethane resin was used.
[0261]
Table 5 shows the evaluation results.
[0262]
[Table 5]

[0263]
As is clear from Table 5, in the evaluation of the image forming method of performing double-sided copying using the electronic RDH, the combination No. 1 using the organic photoreceptor of the present invention and the toner was used. The evaluations of white spots, black spots, cleaning properties, and the like of the samples Nos. 1 to 15 and 17 to 23 were higher than practically acceptable levels. No. 16 (toner is outside the scope of the present invention), the white dropout, the cleaning property is significantly deteriorated, and the resolution is lowered. No. Sample No. 24 (photoreceptor is outside the scope of the present invention) has significant white spots and black spots, cracks, and reduced resolution. No. 25 (the toner and the photoreceptor are outside the present invention) have both white spots and black spots, cracks are generated, the cleaning property is deteriorated, and the resolution is lowered. Also, the combination No. 1 using the organic photoreceptor of the present invention and toner was used. Of the photoreceptors having a charge transport layer containing a charge transport material having a content of the most isomer component in the stereoisomer mixture of 40 to 90% by mass among the mixture of 1 to 15 and 17 to 23, a photoreceptor is used. The combination No. Combination Nos. 1 to 15, 17, and 19 to 21 using the photoconductors having the contents of 37.5 and 92.5 were used. The improvement effect is superior to 18, 22, and 23. Further, the combination No. satisfying the above conditions (2) and (5). Nos. 1-3, 5-7, 10, 11, 19-21, etc. do not satisfy both conditions (2) and (5). The effect is superior to 4, 8, 9, 12 to 15 and the like. In particular, a charge transporting material containing a toner satisfying all of the above conditions (1) to (5) and a charge transporting material containing 40 to 90% by mass of the most isomer component in the stereoisomer mixture. No. 1 using a photoreceptor having a surface layer as a surface layer. Samples Nos. 1 to 3 and 19 to 21 are found to have significantly improved both white and black image defects, good cleaning properties, and excellent evaluations of image density and resolution.
[0264]
Example 2
Synthesis Example 1 (Synthesis Example of Exemplified Compound T83)
[0265]
Embedded image

[0266]
10 g of the compound represented by the above formula was dissolved in 40 ml of dimethylformamide, heated to 40 ° C., and 9.2 g of phosphorus oxychloride was added dropwise little by little (heat was raised to 40 to 70 ° C.). The reaction solution was stirred for 3 hours while controlling the temperature around 70 ° C. After cooling to 40 ° C, excess phosphorus oxychloride was sufficiently hydrolyzed, and the precipitated crystals were separated by filtration, suspended and washed with water, and washed repeatedly until the washing liquid became neutral. 9.25 g (85%) of the bisformyl compound obtained are obtained.
[0267]
Embedded image

[0268]
4 g of the bisformyl compound obtained above and 9.3 g of cinnamyl triphosphonium bromide were dissolved in 50 ml of tetrahydrofuran. While maintaining the reaction solution at about 20 ° C., 1.7 g of sodium methoxide was added little by little (exothermic). After stirring for 2 hours, 30 ml of water was added, and purification was performed by a conventional method to obtain 3.37 g (62%) of yellow crystals. When this compound was subjected to elemental analysis and mass spectrometry, the results were as shown in Table 6 below, and it was confirmed that the compound was the exemplary compound T83.
[0269]
Elemental analysis (C ₅₆ H ₄₀ N ₂ )
[0270]
[Table 6]

[0271]
Mass spectrometry (C ₅₆ H ₄₀ N ₂ )
Mw (calculated value) = 740
Mw ⁺ (Actual value) = 740
The compound of T83 obtained by the above synthesis is designated as T83-1. This T83-1 had a cis-cis / cis-trans / trans-trans mixture ratio of 1.7 / 3.0 / 1.0 as a result of measurement by liquid chromatography (HPCL) described below. The structural formulas of T83cis-cis and T83trans-trans are shown below.
[0272]
Liquid chromatography measurement conditions
Measuring machine: Shimadzu LC6A (manufactured by Shimadzu Corporation)
Column: CLC-SIL (manufactured by Shimadzu Corporation)
Detection wavelength: 290 nm
Mobile phase: n-hexane / dioxane = 10 to 500/1
Mobile phase flow rate: about 1 ml / min
Sample (T83) solvent: n-hexane / dioxane = 10/1
Sample (T83): 3 mg / solvent 10 ml
[0273]
Embedded image

[0274]
A compound in which T83-1 obtained above was separated into a cis-cis form, a cis-trans form, and a trans-trans form using liquid chromatography was also obtained. The cis-cis T83 is referred to as T83c-c, the cis-trans T83 is referred to as T83ct, and the trans-trans T83 is referred to as T83t-t. T83 having a mixing ratio of cis-cis / cis-trans / trans-trans as shown in Table 7 by using four compounds T83-1, T83c-c, T83ct, and T83t-t and changing the mixing ratio. -2 to T83-8 were prepared.
[0275]
Production of photoconductors 10 to 18
Photoconductors 10 to 18 were produced in the same manner as photoconductors 1 to 9 except that T20-1 to T20-8 and T20t-t were replaced with T83-1 to T83-8 and T83c-c.
[0276]
[Table 7]

[0277]
Evaluation
The photosensitive members 10 to 18 and the developers 1 to 16 were combined as shown in Table 8 and evaluated in the same manner as in Example 1. Table 9 shows the evaluation results.
[0278]
[Table 8]

[0279]
[Table 9]

[0280]
As is clear from Table 9, in the evaluation of the image forming method of performing double-sided copying using the electronic RDH, the combination No. 1 using the organic photoreceptor and the toner of the present invention was used. Each of the samples Nos. 31 to 45 and 47 to 53 has the evaluation of white spots, black spots, cleaning properties, etc., which is at or above a level at which there is no practical problem. No. 46 (the toner is outside the scope of the present invention), the white dropout, the cleaning property is significantly deteriorated, and the resolution is lowered. No. Sample No. 54 (photoreceptor is outside the scope of the present invention) has significant white spots and black spots, cracks, and lower resolution. No. 55 (the toner and the photoreceptor are out of the present invention) have both white spots and black spots, cracks are generated, the cleaning property is deteriorated, and the resolution is lowered. Also, the combination No. 1 using the organic photoreceptor of the present invention and toner was used. Of the photoreceptors having a charge transporting layer containing a charge transporting substance having a content of the most isomer component in the stereoisomer mixture of 40 to 90% by mass in the mixture of the stereoisomers among 31 to 45 and 47 to 53, a photoconductor having a surface layer is used. The combination No. Combination Nos. 31 to 45, 47, and 49 to 51 using the photoconductors having the contents of 37.5 and 92.5 are used. The improvement effect is superior to 48, 52, 53. Further, the combination No. satisfying the above conditions (2) and (5). Combination Nos. 31 to 33, 35 to 37, 40, 41, 49 to 51, etc., do not satisfy both conditions (2) and (5). The effect is superior to 34, 38, 39, 42 to 45, and the like. In particular, a charge transporting material containing a toner satisfying all of the above conditions (1) to (5) and a charge transporting material containing 40 to 90% by mass of the most isomer component in the stereoisomer mixture. No. 1 using a photoreceptor having a surface layer as a surface layer. Nos. 31 to 33 and 49 to 51 have remarkably improved image defects of white and black spots, have good cleaning properties, and are also excellent in evaluation of image density and resolution.
[0281]
【The invention's effect】
As is clear from the above examples, the image forming method using the organic photoreceptor and the toner of the present invention is used in an image forming method for double-sided image formation using an electronic RDH in which the temperature and humidity around the photoreceptor change drastically. However, it is possible to prevent generation of contradictory image defects such as white spots and black spots, to prevent generation of cracks, to form an electrophotographic image having excellent cleaning properties and good resolution.
[Brief description of the drawings]
FIG. 1 shows an image that can be suitably used in an image forming method of forming a double-sided image by transferring and fixing a toner image formed on an organic photoreceptor to recording paper using the electronic RDH of the present invention. FIG. 1 is a diagram illustrating an entire configuration of a forming apparatus (digital copying machine).
FIG. 2A is an explanatory diagram illustrating a projected image of a toner particle having no corner, and FIGS. 2B and 2C are explanatory diagrams illustrating a projected image of a toner particle having a corner.
FIG. 3 is a perspective view illustrating an example of a polymerization toner reaction device.
FIG. 4 is a sectional view showing an example of a polymerization toner reaction device.
FIG. 5 is a schematic view showing a specific example of the shape of a stirring blade.
[Explanation of symbols]
A Image reading unit
B Image processing unit
C Image storage unit
D Image forming unit
28 Operation unit
81 Automatic Document Feeder
82 Document Set Table
83 Paper feed roller
84 drive roller
86 belt
87 Original discharge roller
88 Switching Guide
89 Guide plate
90 reversing roller
92 driven roller
94 Document output tray
121 manuscript
122 Platen glass (platen glass)
123 Halogen light source
124 mirror
125 mirror
126 Movable mirror unit
127 mirror
128 lens reading unit
129 Imaging lens
130 CCD line sensor
141 drive motor
142 polygon mirror
143 Reflecting mirror
151 Photoconductor drum
152 charger
153 Developer
157 Transfer pole
158 Separation pole
159 Cleaning device
160 fixing device
171-174 cassette
175 Recording paper transport mechanism
176 Recording paper output tray
177 First switching claw
180 second switching claw
181 reversing roller
183 Rear reversing transport path

Claims (12)

In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image forming method comprising: a charge transport layer containing a transport substance; and a toner used for forming the toner image, wherein a variation coefficient of a shape factor of toner particles is 16% or less. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed on recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image, characterized in that the toner used for forming the toner image is a charge transport layer containing a transport material, and contains 65% by number or more of toner particles having a shape factor in the range of 1.2 to 1.6. Forming method. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image forming method, which is a charge transporting layer containing a transporting substance, wherein the toner used for forming the toner image contains 50% by number or more of toner particles having no corners. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed to recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. The toner used for forming the toner image, which is a charge transport layer containing a transport material, has a natural logarithm lnD on the horizontal axis, where the particle diameter of the toner particles is D (μm). The relative frequency (m ₁ ) of the toner particles included in the most frequent class in the histogram showing the number-based particle size distribution divided into a plurality of classes at 23 intervals, and the toner included in the class having the second highest frequency after the most frequent class An image forming method, wherein the sum (M) of the relative frequency (m ₂ ) of the particles is 70% or more. In an image forming method in which a toner image formed on an organic photoreceptor is transferred and fixed on recording paper using an electronic RDH to form a double-sided image, the organic photoreceptor has a surface layer having a charge of a stereoisomer mixture. An image forming method comprising: a charge transporting layer containing a transporting substance; wherein the toner used for forming the toner image has a coefficient of variation of the number of toner particles of 27% or less. The image forming method according to any one of claims 1 to 5, wherein the content of the most polyisomer component in the stereoisomer mixture is 40 to 90% by mass. The image forming method according to any one of claims 1 to 6, wherein the organic photoconductor has a charge generation layer and a charge transport layer on a conductive support. The image forming method according to any one of claims 1 to 7, wherein the toner is a polymerized toner. 9. The image forming method according to claim 8, wherein the toner satisfies all the conditions described in claims 1 to 5. The image forming method according to claim 1, wherein the toner has a number average particle diameter of 3.0 to 8.5 μm. An image forming apparatus that forms an electrophotographic image by using the image forming method according to claim 1. In an organic photoreceptor used for an image forming method of forming a double-sided image by transferring and fixing a toner image formed on the organic photoreceptor to recording paper using electronic RDH, a surface layer of a stereoisomer mixture is used. An organic photoconductor comprising a charge transport layer containing a charge transport material.

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