JP2004077869A - Organic photoreceptor, image forming method, image forming apparatus and processing cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor which improves the transferability of a toner, residual toner cleaning performance and scuffing resistance and is excellent in image characteristics such as sharpness and to provide an image forming method using the organic photoreceptor, an image forming apparatus and a processing cartridge. <P>SOLUTION: The organic photoreceptor has one or more charge transport layers having a total thickness of 5-15 μm on a charge generating layer, wherein the uppermost charge transport layer contains a charge transport material which is a mixture of two or more stereoisomers, and a creep rate of the organic photoreceptor (a creep rate shown when a Vickers indentor is pushed down under the load of 20 mN) is 1 to <3.5%. <P>COPYRIGHT: (C)2004,JPO

Description

【００４０】
立体異性体混合物の電荷輸送物質とポリカーボネートの混合比は質量比で電荷輸送物質１に対し、ポリカーボネート０．５〜３．０の比率が好ましく、更に０．８〜２．０の比率が好ましいが、この比率は電荷輸送物質或いはポリカーボネートの種類によって、或いはその他の添加剤の存在により変化し、絶対的なものではない。
【００４１】
本発明のクリープ率は１％以上、３．５％未満であるが、２．０％以上、３．２％以下がより好ましい。
【００４２】
又、数平均一次粒径が１０ｎｍ以上、１００ｎｍ未満の疎水性無機粒子を混在させることがより好ましい。疎水性無機粒子のより好ましい数平均粒径は１０ｎｍ以上、９０ｎｍ以下、最も好ましくは１０ｎｍ以上、５０ｎｍ未満である。表面層に含有される無機粒子の数平均一次粒子径が１０ｎｍ未満でも、１００ｎｍ以上でも、前記粘弾性特性が得られにくく、上記のような改善効果が得られにくい。
【００４３】
本発明に用いられる１０ｎｍ以上、１００ｎｍ未満の無機粒子としては、シリカ、酸化亜鉛、酸化チタン、酸化スズ、酸化アンチモン、酸化インジウム、酸化ビスマス、スズをドープした酸化インジウム、アンチモンやタンタルをドープした酸化スズ、酸化ジルコニウム等の微粒子を好ましく用いることができるが、これらの中でもコスト、粒径の調整や表面処理の容易さ等からシリカ、特に表面を疎水化した疎水性シリカが好ましい。
【００４４】
本発明の無機粒子の数平均一次粒径は、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３００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値を算出する。
【００４５】
上記疎水性シリカの疎水化度は、メタノールに対する濡れ性の尺度（メタノールウェッタビリティ）で示される疎水化度で５０％以上のものが好ましい。疎水化度が５０％未満であると、シリカ表面に多量に残在する水酸基がバインダー樹脂と結合し、クリープ率が小さくなり、且つ感光体表面に湿気を帯びやすく、残留電位が上昇したり、クリーニング不良も発生しやすくなる。より好ましい疎水化度は６５％以上、最も好ましくは７０％以上である。
【００４６】
疎水化度を表すメタノールウェッタビリティとは、メタノールに対するシリカ微粉末の濡れ性を評価するものである。濡れ性の測定は以下の方法で行う。内容量２５０ｍｌのビーカーに入れた蒸留水５０ｍｌに、測定対象のシリカ微粉末を０．２ｇ添加して撹拌する。次にメタノールを先端が液体中に浸漬されているビュレットからゆっくり撹拌した状態でシリカ微粉末の全体が濡れるまでゆっくり滴下する。このシリカ微粉末を完全に濡らすために必要なメタノールの量をａ（ｍｌ）とした時、下記式（１）により疎水化度を算出する。
【００４７】
式（１）　　　疎水化度＝ａ／（ａ＋５０）×１００
上記疎水性シリカは、公知の湿式法もしくは乾式法で生成されたシリカ粉末をを疎水化することにより得られる。特に乾式法（ケイ素化ハロゲン化合物の蒸気相酸化）により生成されたいわゆるヒュームドシリカと称されるものを疎水化剤で処理したものが、水分吸着サイトが少なく好ましい。これは従来公知の技術によって製造されるものである。例えば四塩化ケイ素ガスの酸水素焔中における熱分解酸化反応を利用するもので、基礎となる反応式は次のようなものである。
【００４８】
ＳｉＣｌ_４＋２Ｈ_２＋Ｏ_２→ＳｉＯ_２＋４ＨＣｌ
又、この製造工程において例えば、塩化アルミニウム又は、塩化チタンなど他の金属ハロゲン化合物をケイ素ハロゲン化合物と共に用いることによってシリカと他の金属酸化物の複合微粉体を得ることも可能である。
【００４９】
シリカ粉末の疎水化処理は、シリカ微粉末を撹拌等によりクラウド状に分散させたものに、アルコール等で溶解した疎水化処理剤溶液を噴霧するか或いは気化した疎水化処理剤を接触させて付着させる乾式処理、又は、シリカ粉末を溶液中に分散させ、その中に疎水化処理剤を滴下して付着させる湿式処理等の従来公知の方法で行うことが出来る。
【００５０】
疎水化処理剤としては、公知の化合物を用いることが出来、具体例を下記に挙げる。又、これらの化合物は組み合わせて使用しても良い。
【００５１】
チタンカップリング剤としてはテトラブチルチタネート、テトラオクチルチタネート、イソプロピルトリイソステアロイルチタネート、イソプロピルトリデシルベンゼンスルフォニルチタネート及びビス（ジオクチルパイロフォスフェート）オキシアセテートチタネート等が挙げられる。
【００５２】
シランカップリング剤としてはγ−（２−アミノエチル）アミノプロピルトリメトキシシラン、γ−（２−アミノエチル）アミノプロピルメチルジメトキシシラン、γ−メタクリロキシプロピルトリメトキシシラン、Ｎ−β−ビニルベンジルアミノエチル−Ｎ−γ−アミノプロピルトリメトキシシラン塩酸塩、ヘキサメチルジシラザン、メチルトリメトキシシラン、ブチルトリメトキシシラン、イソブチルトリメトキシシラン、ヘキシルトリメトキシシラン、オクチルトリメトキシシラン、デシルトリメトキシシラン、ドデシルトリメトキシシラン、フェニルトリメトキシシラン、ｏ−メチルフェニルトリメトキシシラン及びｐ−メチルフェニルトリメトキシシラン等が挙げられる。
【００５３】
シリコーンオイルとしてはジメチルシリコーンオイル、メチルフェニルシリコーンオイル及びアミノ変性シリコーンオイル等が挙げられる。
【００５４】
これらの疎水化処理剤は、シリカ粉末に対して１〜４０質量％添加して被覆することが好ましく、３〜３０質量％がより好ましい。
【００５５】
又、上記表面疎水化剤としてハイドロジェンポリシロキサン化合物を用いてもよい。該ハイドロジェンポリシロキサン化合物の分子量は１０００〜２００００のものが一般に入手しやすく、又、黒ポチ発生防止機能も良好である。特にメチルハイドロジェンポリシロキサンを最後の表面処理に用いると良好な効果が得られる。
【００５６】
本発明では上記疎水化処理された疎水性シリカを有機感光体の表面層にバインダーと共に含有させるが表面層のシリカ粒子の割合はバインダーに対して１〜２０質量％、好ましくは２〜１５質量％、最も好ましくは２〜１０質量％で使用されるのがよい。２０質量％を超えると、残留電位が上昇し、画像濃度が低下したり、トナーの転写性を低下させやすい。一方、１質量％未満だとクリーニング不良や、耐摩耗性の低下を起こしやすい。
【００５７】
又、表面層となる電荷輸送層には、上記高弾性のポリカーボネートのバインダー樹脂と立体異性体混合物の電荷輸送物質が含有されが、その他にも該電荷輸送層には酸化防止剤をバインダー樹脂に対して１〜１０質量％存在させることが好ましい。
【００５８】
以上のような構成を選択採用することにより、前記した膜物性の電荷輸送層を実現させることができ、このような電荷輸送層を表面層を有する有機感光体は残留トナークリーニング性を改善すると同時に、耐傷性、耐摩耗性を改善し、長期に亘り鮮鋭性が良好な電子写真画像を提供することができる。
【００５９】
以下、本発明に適用される有機感光体の構成について記載する。
本発明において、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感光体を全て含有する。
【００６０】
本発明の電荷輸送層とは、光露光により電荷発生層で発生した電荷キャリアを有機感光体の表面に輸送する機能を有する層を意味し、該電荷輸送機能の具体的な検出は、電荷発生層と電荷輸送層を導電性支持体上に積層し、光導伝性を検知することにより確認することができる。
【００６１】
本発明の有機感光体の層構成は、基本的には導電性支持体上に電荷発生層及び電荷輸送層の感光層から構成される。最も好ましい構成としては、感光層を電荷発生層と複数の電荷輸送層で構成し、最上層を本発明の２種以上の立体異性体混合物の電荷輸送物質を含有し、且つクリープ率（ビッカース圧子を荷重２０ｍＮで押し込んだ時のクリープ率）が１％以上３．５％未満の特性を有する電荷輸送層の構成にすることである。
【００６２】
以下に本発明に用いられる具体的な感光体の構成について記載する。
導電性支持体
本発明の感光体に用いられる導電性支持体としてはシート状或いは円筒状の導電性支持体が用いられる。
【００６３】
本発明の円筒状の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。
【００６４】
導電性支持体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。
【００６５】
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。
【００６６】
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前記した中間層を設けることが好ましい。
【００６７】
本発明の中間層には前記した吸水率が小さいバインダー樹脂中に酸化チタンを含有させることが好ましい。該酸化チタン粒子の平均粒径は、数平均一次粒径で１０ｎｍ以上４００ｎｍ以下の範囲が良く、１５ｎｍ〜２００ｎｍが好ましい。
１０ｎｍ未満では中間層によるモアレ発生の防止効果が小さい。一方、４００ｎｍより大きいと、中間層塗布液の酸化チタン粒子の沈降が発生しやすく、その結果中間層中の酸化チタン粒子の均一分散性が悪く、又黒ポチも増加しやすい。数平均一次粒径が前記範囲の酸化チタン粒子を用いた中間層塗布液は分散安定性が良好で、且つこのような塗布液から形成された中間層は黒ポチ発生防止機能の他、環境特性が良好で、且つ耐クラッキング性を有する。
【００６８】
本発明に用いられる酸化チタン粒子の形状は、樹枝状、針状および粒状等の形状があり、このような形状の酸化チタン粒子は、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で且つ粒状のものが最も良い。
【００６９】
本発明の酸化チタン粒子は表面処理されていることが好ましく、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を用いた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を行い、最後に反応性有機ケイ素化合物を用いた表面処理を行うことが好ましい。
【００７０】
尚、アルミナ処理、シリカ処理、ジルコニア処理とは酸化チタン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。
【００７１】
この様に、酸化チタン粒子の様な酸化チタン粒子の表面処理を少なくとも２回以上行うことにより、酸化チタン粒子表面が均一に表面被覆（処理）され、該表面処理された酸化チタン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酸化チタン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。
【００７２】
上記反応性有機ケイ素化合物としては下記一般式（１０）で表される化合物が挙げられるが、酸化チタン表面の水酸基等の反応性基と縮合反応をする化合物であれば、下記化合物に限定されない。
【００７３】
一般式（１０）
（Ｒ）_ｎ−Ｓｉ−（Ｘ）_４−ｎ
（式中、Ｓｉはケイ素原子、Ｒは該ケイ素原子に炭素が直接結合した形の有機基を表し、Ｘは加水分解性基を表し、ｎは０〜３の整数を表す。）
一般式（１０）で表される有機ケイ素化合物において、Ｒで示されるケイ素に炭素が直接結合した形の有機基としては、メチル、エチル、プロピル、ブチル、ペンチル、ヘキシル、オクチル、ドデシル等のアルキル基、フェニル、トリル、ナフチル、ビフェニル等のアリール基、γ−グリシドキシプロピル、β−（３，４−エポキシシクロヘキシル）エチル等の含エポキシ基、γ−アクリロキシプロピル、γ−メタアクリロキシプロピルの含（メタ）アクリロイル基、γ−ヒドロキシプロピル、２，３−ジヒドロキシプロピルオキシプロピル等の含水酸基、ビニル、プロペニル等の含ビニル基、γ−メルカプトプロピル等の含メルカプト基、γ−アミノプロピル、Ｎ−β（アミノエチル）−γ−アミノプロピル等の含アミノ基、γ−クロロプロピル、１，１，１−トリフロオロプロピル、ノナフルオロヘキシル、パーフルオロオクチルエチル等の含ハロゲン基、その他ニトロ、シアノ置換アルキル基を挙げられる。また、Ｘの加水分解性基としてはメトキシ、エトキシ等のアルコキシ基、ハロゲン基、アシルオキシ基が挙げられる。
【００７４】
また、一般式（１０）で表される有機ケイ素化合物は、単独でも良いし、２種以上組み合わせて使用しても良い。
【００７５】
また、一般式（１０）で表される有機ケイ素化合物の具体的化合物で、ｎが２以上の場合、複数のＲは同一でも異なっていても良い。同様に、ｎが２以下の場合、複数のＸは同一でも異なっていても良い。又、一般式（１０）で表される有機ケイ素化合物を２種以上を用いるとき、Ｒ及びＸはそれぞれの化合物間で同一でも良く、異なっていても良い。
【００７６】
又、表面処理に用いる好ましい反応性有機ケイ素化合物としてはポリシロキサン化合物が挙げられる。該ポリシロキサン化合物の分子量は１０００〜２００００のものが一般に入手しやすく、又、黒ポチ発生防止機能も良好である。
【００７７】
特にメチルハイドロジェンポリシロキサンを最後の表面処理に用いると良好な効果が得られる。
【００７８】
感光層
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。
【００７９】
本発明の有機感光体には、電荷発生物質として、例えば、他の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単独で或いは併用して用いることができる。
【００８０】
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０．１μｍ〜２μｍが好ましい。
【００８１】
電荷輸送層
本発明の電荷輸送層は一層以上の電荷輸送層の構成を有する。最上層の電荷輸送層については前記したが、最上層以外の電荷輸送層は公知の電荷輸送層の構成を採用することもできる。
【００８２】
電荷輸送層には電荷輸送物質（ＣＴＭ）及び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。
【００８３】
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以外に公知の電荷輸送物質（ＣＴＭ）を用いることができる。特に最上層以外の電荷輸送層では、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。
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ＣＴＭは高移動度で、且つ組み合わされるＣＧＭとのイオン化ポテンシャル差が０．５（ｅＶ）以下の特性を有するものであり、好ましくは０．３０（ｅＶ）以下である。
【００８４】
ＣＧＭ、ＣＴＭのイオン化ポテンシャルは表面分析装置ＡＣ−１（理研計器社製）で測定される。
【００８５】
電荷輸送層（ＣＴＬ）に用いられるバインダー樹脂としては熱可塑性樹脂、熱硬化性樹脂いずれの樹脂かを問わない。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構造のうちの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。これらの中で吸水率が小さく、ＣＴＭの分散性、電子写真特性が良好なポリカーボネート樹脂が最も好ましい。
【００８６】
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５０〜２００質量部が好ましい。
【００８７】
又、電荷輸送層（１層以上、好ましくは２〜３層、最も好ましくは２層）の膜厚の合計は５〜１５μｍであり、好ましくは８〜１５μｍである。膜厚が５μｍ未満だと帯電電位が不十分になりやすく、１５μｍを超えると、鮮鋭性が劣化しやすい。
【００８８】
次に、本発明の立体異性体混合物の電荷輸送物質について説明する。
本発明の有機感光体は最上層の電荷輸送層が、立体異性体混合物の電荷輸送物質を含有することを特徴とする。立体異性体混合物の電荷輸送物質は、比較的高分子量の化学構造を有しており、電荷輸送層を構成するバインダー樹脂との相溶性が良好となり、本発明のクリープ率１％以上、３５％未満の特性を達成しやすい。又、白ヌケや黒ポチ等の画像欠陥が防止され、且つ帯電性や感度等の電子写真特性が良好な有機感光体が得られる。そして、該立体異性体混合物の最大成分の含有率は２５〜８０質量％であることが好ましい。最大成分の含有率が８０質量％より大きいと、電荷輸送物質の分散性が劣化し、画像濃度が低下したり、白ヌケや黒ポチ等の画像欠陥が発生しやすい。一方、２５質量％より小さいと、立体異性体の構造異性の種類が多くなり、安定した電子写真特性が得られにくい。
【００８９】
上記のような効果は立体異性体混合物の電荷輸送物質を用いることにより、感光層、例えば電荷輸送層のバインダーと電荷輸送物質の相溶性が良好となり、電荷輸送層の膜質及び電子写真特性が向上し、感光体とトナーの付着力が小さくなり、トナーの転写性、クリーニング性を改良するためと思われる。
【００９０】
又、立体異性体構造を有する電荷輸送物質の分子量は５００〜１５００が好ましく、６００〜１０００がより好ましく、６５０〜８５０が最も好ましい。このような高分子量の電荷輸送物質を用いることにより、電荷輸送層の膜質の向上を図ることができ、前記した本発明の効果をより顕著にすることができる。
【００９１】
立体異性体混合物の電荷輸送物質とは同一の化学構造式を有する電荷輸送物質の化合物がその中の原子又は原子団の立体配置を異にすることによって起こる異性構造を持つものを云う。
【００９２】
本発明の立体異性体混合物の電荷輸送物質としては、ビス（アリールエテニルフェニル）アニリン系化合物又はビス又はトリブタジエン系化合物が好ましい。
【００９３】
本発明のビス（アリールエテニルフェニル）アニリン系化合物とはアニリンの窒素原子に同一化学構造のアリールエテニルフェニル基を２個有する化合物群を云うが、好ましくは下記一般式（１）で示される化合物であり、更に一般式（２）〜一般式（６）のように、アニリン基のオルト或いはパラ位にアルキル基又はアルコキシ基を有するものが好ましい。
【００９４】
【化２】

【００９５】
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。
【００９６】
【化３】

【００９７】
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。
【００９８】
【化４】

【００９９】
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。
【０１００】
【化５】

【０１０１】
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。
【０１０２】
【化６】

【０１０３】
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。
【０１０４】
【化７】

【０１０５】
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。
【０１０６】
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。
【０１０７】
【化８】

【０１０８】
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。
【０１０９】
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。
【０１１０】
【化９】

【０１１１】
【化１０】

【０１１２】
【化１１】

【０１１３】
【化１２】

【０１１４】
【化１３】

【０１１５】
【化１４】

【０１１６】
【化１５】

【０１１７】
【化１６】

【０１１８】
【化１７】

【０１１９】
【化１８】

【０１２０】
【化１９】

【０１２１】
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。
【０１２２】
【化２０】

【０１２３】
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。
【０１２４】
【化２１】

【０１２５】
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。
【０１２６】
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。
【０１２７】
【化２２】

【０１２８】
【化２３】

【０１２９】
【化２４】

【０１３０】
【化２５】

【０１３１】
【化２６】

【０１３２】
【化２７】

【０１３３】
【化２８】

【０１３４】
中間層、電荷発生層、電荷輸送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。
【０１３５】
次に有機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。なお保護層は前記円形量規制型塗布加工方法を用いるのが最も好ましい。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。
【０１３６】
又、本発明は前記有機感光体と以下に記すような均一な形状係数やシャープな粒度分布を有するトナーを併用した画像形成方法を採用することにより、階調性の高い且つ鮮鋭な電子写真画像を形成することが出来る。
【０１３７】
（１）形状係数が１．２〜１．６の範囲にあるトナー粒子を６５個数％以上含有するトナー
形状係数が１．２より小さいとトナーの形状が真球に近くなり、トナーの感光体との接着強度が増大し、クリーニング不良が発生しやすい。一方、１．６より大きくなるとトナーが破砕され、微粉化されやすく、このこともクリーニング不良の原因となる。即ち、形状係数が１．２〜１．６の範囲にあるトナー粒子を６５個数％以上、さらに好ましくは７０個数％以上含有するトナーはクリーニング性が良好で、且つ微粉化されにくいトナーを多量に含んだトナーであり、本発明の感光体と併用することにより、長期に亘り、良好なクリーニング性と、良好な画像形成を可能にする。
【０１３８】
（２）角がないトナー粒子を５０個数％以上含有するトナー
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破砕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、角がないトナー粒子の割合が５０個数％以上、更に好ましくは７０個数％以上であることにより、現像剤搬送部材などとのストレスにより微細な粒子の発生などがおこりにくくなり、微細なトナーの発生によるクリーニング不良を防止でき、本発明の感光体と併用することにより、長期に亘り、良好なクリーニング性と、良好な画像形成を可能にする。そのためには角がないトナー粒子の割合が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％以上である。
【０１３９】
（３）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％以上含有するトナー
相対度数（ｍ_１）と、相対度数（ｍ_２）の和（Ｍ）が７０％以上のトナーであることにより、該トナーを構成するトナー粒子の粒度分布がシャープとなり、安定したトナー画像の形成が可能となり、その結果、本発明の感光体と併用することにより、長期に亘り、良好なクリーニング性と、良好な画像形成を可能にする。
【０１４０】
（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％以下且つトナー粒子の形状係数の変動係数が１６％以下であるトナー
トナーの形状係数の変動係数が１６％以下であり、且つトナーの個数粒度分布における個数変動係数が２７％以下であるトナーを使用することにより、クリーニング性、細線再現性に優れ、高品位な画質を長期にわたって形成することができる。
【０１４１】
トナーの個数変動係数は２７％以下であるが、好ましくは２５％以下である。
トナー粒子の形状係数の変動係数が１６％以下、より好ましくは１４％以下である。このことにより、トナーを構成するトナー粒子の形状分布がシャープとなり、安定したトナー画像の形成が可能となり、その結果、本発明の感光体と併用することにより、長期に亘り、良好なクリーニング性と、良好な画像形成を可能にする。
【０１４２】
又、トナーは形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上であり、形状係数の変動係数が１６％以下であるトナーを使用することが好ましい。このようなトナーは感光体との付着力が小さく、クリーニング性が良好である。
【０１４３】
また、角がないトナー粒子を５０個数％以上とし、個数粒度分布における個数変動係数を２７％以下に制御することによっても、クリーニング性、細線再現性に優れ、高品位な画質を長期にわたって形成することができる。
【０１４４】
トナーの粒径は、個数平均一次粒径で３〜８μｍ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、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。
【０１４５】
個数平均粒径が３〜８μｍであることにより、定着工程において、現像剤搬送部材に対する付着性の過度なトナーや付着力の低いトナー等の存在を少なくすることができ、現像性を長期に亘って安定化することができるとともに、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。
【０１４６】
トナーの形状係数は、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。
【０１４７】
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。
【０１４８】
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。
【０１４９】
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が６５個数％以上、好ましくは７０個数％以上である。
【０１５０】
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、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方法等があるが、本発明では重合法により作製した重合トナーを用いて形状係数等を本発明の範囲内に作製することが好ましい。
【０１５１】
トナーの形状係数の変動係数は下記式から算出される。
変動係数＝〔Ｓ／Ｋ〕×１００（％）
〔式中、Ｓ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。〕
この形状係数の変動係数は１６％以下が好ましく、更に好ましくは１４％以下である。形状係数の変動係数が１６％以下であることにより、転写されたトナー層の空隙が減少して定着性が向上し、オフセットが発生しにくくなる。また、帯電量分布がシャープとなり、画質が向上する。
【０１５２】
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、重合トナーの製造過程、即ち樹脂粒子（重合体粒子）を重合、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。
【０１５３】
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。
【０１５４】
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。
【０１５５】
トナー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−ＩＩ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。
【０１５６】
トナー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。
個数変動係数＝〔Ｓ／Ｄｎ〕×１００（％）
〔式中、Ｓは個数粒度分布における標準偏差を示し、Ｄｎは個数平均粒径（μｍ）を示す。〕
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。
【０１５７】
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。
【０１５８】
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、すなわち、図５（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５（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。
【０１５９】
角がないトナー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。
【０１６０】
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。しかしながら、製造コストやエネルギーコストを考慮すると、重合法による重合トナーが好ましい。
【０１６１】
例えば、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。
【０１６２】
本発明のトナーの粒径は、個数平均粒径で３〜８μｍ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、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。
【０１６３】
本発明に好ましく用いられる重合トナーとしては、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ことが好ましい。
【０１６４】
相対度数（ｍ_１）と相対度数（ｍ_２）との和（Ｍ）が７０％以上であることにより、トナー粒子の粒度分布の分散が狭くなるので、当該トナーを画像形成工程に用いることにより選択現像の発生を確実に抑制することができる。
【０１６５】
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。
【０１６６】
〔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。
【０１６７】
形状係数を制御する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。
【０１６８】
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にて単量体を乳化重合し、微粒の重合粒子を製造し、その後に、有機溶媒、凝集剤等を添加して会合する方法で製造することができる。会合の際にトナーの構成に必要な離型剤や着色剤などの分散液と混合して会合させて調製する方法や、単量体中に離型剤や着色剤などのトナー構成成分を分散した上で乳化重合する方法などがあげられる。ここで会合とは樹脂粒子および着色剤粒子が複数個融着することを示す。
【０１６９】
即ち、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トナーを調製する。
【０１７０】
また、本発明の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、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有機溶媒を加えてもよい。
【０１７１】
なお、本発明で用いられる形状係数等の均一なトナーを作製するための材料や製造方法、重合トナーの反応装置等については特開２０００−２１４６２９に詳細に記載されている。
《現像剤》
本発明に用いられるトナーは、一成分現像剤でも二成分現像剤でもよいが、好ましくは二成分現像剤である。
【０１７２】
一成分現像剤として用いる場合は、非磁性一成分現像剤として前記トナーをそのまま用いる方法もあるが、通常はトナー粒子中に０．１〜５μｍ程度の磁性粒子を含有させ磁性一成分現像剤として用いる。その含有方法としては、着色剤と同様にして非球形粒子中に含有させるのが普通である。
【０１７３】
又、キャリアと混合して二成分現像剤として用いることができる。この場合は、キャリアの磁性粒子として、鉄、フェライト、マグネタイト等の金属、それらの金属とアルミニウム、鉛等の金属との合金等の従来から公知の材料を用いる。
特にフェライト粒子が好ましい。上記磁性粒子は、その体積平均粒径としては１５〜１００μｍ、より好ましくは２５〜６０μｍのものがよい。
【０１７４】
キャリアの体積平均粒径の測定は、代表的には湿式分散機を備えたレーザ回折式粒度分布測定装置「ヘロス（ＨＥＬＯＳ）」（シンパティック（ＳＹＭＰＡＴＥＣ）社製）により測定することができる。
【０１７５】
キャリアは、磁性粒子が更に樹脂により被覆されているもの、あるいは樹脂中に磁性粒子を分散させたいわゆる樹脂分散型キャリアが好ましい。コーティング用の樹脂組成としては、特に限定は無いが、例えば、オレフィン系樹脂、スチレン系樹脂、スチレン／アクリル系樹脂、シリコーン系樹脂、エステル系樹脂或いはフッ素含有重合体系樹脂等が用いられる。また、樹脂分散型キャリアを構成するための樹脂としては、特に限定されず公知のものを使用することができ、例えば、スチレンアクリル樹脂、ポリエステル樹脂、フッ素系樹脂、フェノール樹脂等を使用することができる。
【０１７６】
次に、本発明の有機感光体を用いた画像形成装置について説明する。
図１に示す画像形成装置１は、デジタル方式による画像形成装置であって、画像読取り部Ａ、画像処理部Ｂ、画像形成部Ｃ、転写紙搬送手段としての転写紙搬送部Ｄから構成されている。
【０１７７】
画像読取り部Ａの上部には原稿を自動搬送する自動原稿送り手段が設けられていて、原稿載置台１１上に載置された原稿は原稿搬送ローラ１２によって１枚宛分離搬送され読み取り位置１３ａにて画像の読み取りが行われる。原稿読み取りが終了した原稿は原稿搬送ローラ１２によって原稿排紙皿１４上に排出される。
【０１７８】
一方、プラテンガラス１３上に置かれた場合の原稿の画像は走査光学系を構成する照明ランプ及び第１ミラーから成る第１ミラーユニット１５の速度ｖによる読み取り動作と、Ｖ字状に位置した第２ミラー及び第３ミラーから成る第２ミラーユニット１６の同方向への速度ｖ／２による移動によって読み取られる。
【０１７９】
読み取られた画像は、投影レンズ１７を通してラインセンサである撮像素子ＣＣＤの受光面に結像される。撮像素子ＣＣＤ上に結像されたライン状の光学像は順次電気信号（輝度信号）に光電変換されたのちＡ／Ｄ変換を行い、画像処理部Ｂにおいて濃度変換、フィルタ処理などの処理が施された後、画像データは一旦メモリに記憶される。
【０１８０】
画像形成部Ｃでは、画像形成ユニットとして、像担持体であるドラム状の感光体２１と、その外周に、該感光体２１を帯電させる帯電手段（帯電工程でもある）２２、帯電した感光体の表面電位を検出する電位検出手段２２０、現像手段（現像工程でもある）２３、転写手段（転写工程でもある）である転写搬送ベルト装置４５、前記感光体２１のクリーニング手段（クリーニング工程でもある）２６及び光除電手段としてのＰＣＬ（プレチャージランプ）２７が各々動作順に配置されている。また、現像手段２３の下流側には感光体２１上に現像されたパッチ像の反射濃度を測定する反射濃度検出手段２２２が設けられている。感光体２１には、本発明の有機感光体が使用され、図示の時計方向に駆動回転される。
【０１８１】
回転する感光体２１へは帯電手段２２による一様帯電がなされた後、像露光手段（像露光工程でもある）としての露光光学系３０により画像処理部Ｂのメモリから呼び出された画像信号に基づいた像露光が行われる。書き込み手段である像露光手段としての露光光学系３０は図示しないレーザダイオードを発光光源とし、回転するポリゴンミラー３１、ｆθレンズ３４、シリンドリカルレンズ３５を経て反射ミラー３２により光路が曲げられ主走査がなされるもので、感光体２１に対してＡｏの位置において像露光が行われ、感光体２１の回転（副走査）によって静電潜像が形成される。本実施の形態の一例では文字部に対して露光を行い静電潜像を形成する。
【０１８２】
本発明の画像形成方法においては、感光体上に静電潜像を形成するに際し、像露光をスポット面積が２×１０^−９ｍ^２以下の露光ビームを用いて行うことが好ましい。このような小径のビーム露光を行っても、本発明の有機感光体は、該スポット面積に対応した画像を忠実に形成することができる。より好ましいスポット面積は、０．０１×１０^−９〜１×１０^−９ｍ^２である。その結果４００ｄｐｉ（ｄｐｉとは２．５４ｃｍ当たりのドット数）以上で、２５６階調を実現するところのきわめて優れた画像品質を達成することができる。
【０１８３】
前記ビーム光のスポット面積とは該ビーム光の強度がピーク強度の１／ｅ^２以上の光強度に対応する面積で表される。
【０１８４】
用いられる光ビームとしては半導体レーザを用いた走査光学系、及びＬＥＤや液晶シャッター等の固体スキャナー等があり、光強度分布についてもガウス分布及びローレンツ分布等があるがそれぞれのピーク強度の１／ｅ^２までの部分をスポット面積とする。
【０１８５】
感光体２１上の静電潜像は現像手段２３によって反転現像が行われ、感光体２１の表面に可視像のトナー像が形成される。転写紙搬送部Ｄでは、画像形成ユニットの下方に異なるサイズの転写紙Ｐが収納された転写紙収納手段としての給紙ユニット４１（Ａ）、４１（Ｂ）、４１（Ｃ）が設けられ、また側方には手差し給紙を行う手差し給紙ユニット４２が設けられていて、それらの何れかから選択された転写紙Ｐは案内ローラ４３によって搬送路４０に沿って給紙され、給紙される転写紙Ｐの傾きと偏りの修正を行うレジストローラ対４４によって転写紙Ｐは一時停止を行ったのち再給紙が行われ、搬送路４０、転写前ローラ４３ａ、給紙経路４６及び進入ガイド板４７に案内され、感光体２１上のトナー画像が転写位置Ｂｏにおいて転写極２４及び分離極２５によって転写搬送ベルト装置４５の転写搬送ベルト４５４に載置搬送されながら転写紙Ｐに転写され、該転写紙Ｐは感光体２１面より分離し、転写搬送ベルト装置４５により定着手段５０に搬送される。
【０１８６】
定着手段（定着工程でもある）５０は定着ローラ５１と加圧ローラ５２とを有しており、転写紙Ｐを定着ローラ５１と加圧ローラ５２との間を通過させることにより、加熱、加圧によってトナーを定着させる。トナー画像の定着を終えた転写紙Ｐは排紙トレイ６４上に排出される。
【０１８７】
以上は転写紙の片側への画像形成を行う状態を説明したものであるが、両面複写の場合は排紙切換部材１７０が切り替わり、転写紙案内部１７７が開放され、転写紙Ｐは破線矢印の方向に搬送される。
【０１８８】
更に、搬送機構１７８により転写紙Ｐは下方に搬送され、転写紙反転部１７９によりスイッチバックさせられ、転写紙Ｐの後端部は先端部となって両面複写用給紙ユニット１３０内に搬送される。
【０１８９】
転写紙Ｐは両面複写用給紙ユニット１３０に設けられた搬送ガイド１３１を給紙方向に移動し、給紙ローラ１３２で転写紙Ｐを再給紙し、転写紙Ｐを搬送路４０に案内する。
【０１９０】
再び、上述したように感光体２１方向に転写紙Ｐを搬送し、転写紙Ｐの裏面にトナー画像を転写し、定着手段５０で定着した後、排紙トレイ６４に排紙する。
【０１９１】
図２は分離爪ユニットの平面図、その側面図である図３、更には図４の分離爪の側面図に示すように、有機感光体上への分離爪２５２の当接荷重を切り換えることで、コピー初期の爪傷を低減し、黒スジ発生を防止するようにした。
【０１９２】
しかし、爪傷低減のために分離爪２５２の当接荷重を低くしすぎると転写紙Ｐを有機感光体２１から分離できなくなってＪＡＭが発生するので、当接荷重は好適な範囲に設定する必要がある。
【０１９３】
次に、分離爪２５２の有機感光体２１に対する当接荷重を適切に切り換える当接荷重切換手段２６０について説明する。
【０１９４】
当接荷重切換手段２６０は分離爪２５２と、それを付勢するトルクバネ２５５と、分離爪２５２を有機感光体２１に当接してその当接荷重を調節したり解除したりする当接解除板２６１と、それを取り付けたシャフト２６２に直結したロータリ式の直流ソレノイド２６５から構成されている。
【０１９５】
そして、分離爪２５２はその回動軸２５３を軸受２５４に枢支されてトルクバネ２５５で付勢されており、ロータリ式の直流ソレノイド２６５の通電が切られ、該直流ソレノイド２６５に直結して軸受２６４に回転可能に枢支されているシャフト２６２がバネ力によって戻されて回動すると、該シャフト２６２に取り付けられた当接解除板２６１が下がって分離爪２５２が有機感光体２１の表面に当接し、シャフト２６２が通電されて元の位置に戻ると当接解除板２６１が上がって分離爪２５２の当接を離し当接は解除される。
【０１９６】
また、直流ソレノイド２６５に印加する電圧を切り換えて当接解除板２６１と分離爪２５２との間の接触圧を変更することで、分離爪２５２と有機感光体２１との間の当接荷重を減殺して切り換えることができる。
【０１９７】
前述のように、当接荷重切換手段２６０における分離爪２５２の有機感光体２１への当接荷重の切り換え動作は、直流ソレノイド２６５に印加する電圧を切り換えて行われる。即ち、直流ソレノイド２６５の印加電圧値により、当接解除板２６１が分離爪２５２に当てる位置で該分離爪２５２に掛ける接触圧が、トルクバネ２５５による分離爪２５２の付勢力を減殺させ、有機感光体２１に対する分離爪２５２の当接荷重を適正な所定値に調節して切り換え可能になる。
【０１９８】
尚、前記分離爪２５２と前記有機感光体２１の表面との間の当接荷重は、０．９８〜７．８４ｍＮの範囲の中から選定されて適正な調節値に設定されるのが好ましい。
【０１９９】
一方、固定基板２７１に取り付けられたステッピングモータ２７２が同じく前記固定基板２７１に取り付けられた歯車２７３，２７４，２７５，２７６を介して分離爪ユニット２５０の基板２５１に取り付けられたラック歯車２６７に噛み合い、基板２５１は固定基板２７１のガイド２７１Ａに沿って左右５ｍｍ程度の範囲内で任意の設定位置に移動して停止できるようにしてある。このようにして分離爪２５２と有機感光体２１との当接位置は幅方向に変えられるようにし、長期間幅方向が同じ状態で当接することを避けることが好ましい。
【０２００】
本発明の有機感光体は電子写真複写機、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。
【０２０１】
【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。尚、下記文中「部」とは「質量部」を表す。
【０２０２】
合成例１（例示化合物Ｔ２０の合成例）
【０２０３】
【化２９】

【０２０４】
上記構造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。
【０２０５】
【化３０】

【０２０６】
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。
【０２０７】
【化３１】

【０２０８】
元素分析（Ｃ_５３Ｈ_４９Ｎ）
【０２０９】
【表１】

【０２１０】
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。
【０２１１】
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
【０２１２】
【化３２】

【０２１３】
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。
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〜Ｔ２０−５の化合物を作製した。
【０２１４】
【表２】

【０２１５】
合成例２（例示化合物Ｔ８３の合成例）
【０２１６】
【化３３】

【０２１７】
上記構造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。
【０２１８】
【化３４】

【０２１９】
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３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。
【０２２０】
元素分析（Ｃ_５６Ｈ_４０Ｎ_２）
【０２２１】
【表３】

【０２２２】
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。
【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（Ｔ８３）溶媒：ｎ−ヘキサン／ジオキサン＝１０／１
サンプル（Ｔ８３）：３ｍｇ／溶媒１０ｍｌ
【０２２４】
【化３５】

【０２２５】
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。
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４に示す如くｃｉｓ−ｃｉｓ／ｃｉｓ−ｔｒａｎｓ／ｔｒａｎｓ−ｔｒａｎｓの混合比を持つＴ８３−２〜Ｔ８３−５の化合物を作製した。
【０２２６】
【表４】

【０２２７】
感光体１の作製
下記の様に感光体１を作製した。
【０２２８】
直径１００ｍｍφ、長さ３４６ｍｍの円筒形アルミニウム支持体の表面を切削加工し、表面粗さＲｚ＝１．５（μｍ）の導電性支持体を用意した。
〈中間層〉
下記組成の分散液を同じ混合溶媒にて二倍に希釈し、一夜静置後に濾過（フィルター；日本ポール社製リジメッシュ５μｍフィルター）し、中間層塗布液を作製した。
【０２２９】
ポリアミド樹脂ＣＭ８０００（東レ社製）　　　　　　　　　　　　　１部
酸化チタンＳＭＴ５００ＳＡＳ（テイカ社製）　　　　　　　　　　　３部
メタノール　　　　　　　　　　　　　　　　　　　　　　　　　　１０部
分散機としてサンドミルを用いて、バッチ式で１０時間の分散を行った。
【０２３０】
上記塗布液を用いて前記支持体上に、乾燥膜厚２μｍとなるよう塗布した。
〈電荷発生層〉
Ｙ型チタニルフタロシアニン（Ｃｕ−Ｋα特性Ｘ線回折スペクトル測定で、ブラッグ角２θ（±０．２）の２７．２度に最大ピークを有するチタニルフタロシアニン）　　　　　　　　　　　　　　　　　　　　　　　　　　　　２０部
ポリビニルブチラール樹脂（＃６０００−Ｃ：電気化学工業社製）　１０部
酢酸ｔ−ブチル　　　　　　　　　　　　　　　　　　　　　　　７００部
４−メトキシ−４−メチル−２−ペンタノン　　　　　　　　　　３００部
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０．３μｍの電荷発生層を形成した。
【０２３１】
〈第一電荷輸送層〉
電荷輸送物質（Ｔ２０−１）　　　　　　　　　　　　　　　　　２２５部
バインダー：ポリカーボネート（Ｚ３００：三菱ガス化学社製）　３００部
酸化防止剤（Ｉｒｇａｎｏｘ１０１０：日本チバガイギー社製）　　　６部
ジクロロメタン　　　　　　　　　　　　　　　　　　　　　　２０００部
シリコンオイル（ＫＦ−５４：信越化学社製）　　　　　　　　　　　１部
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乾燥膜厚６μｍの第一電荷輸送層を形成した。
【０２３２】
〈第二電荷輸送層〉
電荷輸送物質（Ｔ２０−１）　　　　　　　　　　　　　　　　　２２５部
バインダー：ポリカーボネート（例示ポリカーボネートＰＣ−１：粘度平均分子量３万）　　　　　　　　　　　　　　　　　　　　　　　　　　３００部
疎水性シリカ（表５記載の疎水性シリカ：平均粒径４０ｎｍ）　　　６０部
酸化防止剤（ＬＳ２６２６：三共社製）　　　　　　　　　　　　　　６部
１，３−ジオキソラン　　　　　　　　　　　　　　　　　　　２０００部
シリコンオイル（ＫＦ−５４：信越化学社製）　　　　　　　　　　　１部
を混合し、超音波を照射できる循環分散装置にて循環分散を行い、表面層塗布液を調製した。この塗布液を前記第一電荷輸送層の上に円型量規制型塗布法により乾燥膜厚４μｍになるように第二電荷輸送層を塗布し、１１０℃で７０分間の乾燥を行い、感光体１を作製した。
【０２３３】
感光体２〜１９の作製
感光体１の作製において、第一、第二の電荷輸送層の電荷輸送物質及び第二電荷輸送層のポリカーボネート及び疎水性シリカを表５のように変化させ、電荷輸送層の合計膜厚を第一電荷輸送層の膜厚を変えて変化させた以外は感光体１と同様にして感光体２〜１９を作製した（但し、感光体１２では第一電荷輸送層は塗布せず）。
【０２３４】
【表５】

【０２３５】
表中、ＰＣ−４は下記構造のポリカーボネートを、Ｔ１０１は下記構造の電荷輸送物質を示す。
【０２３６】
【化３６】

【０２３７】
本発明に用いるトナー及び該トナーを用いた現像剤を作製した。
（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。
【０２３８】
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。
【０２３９】
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。
【０２４０】
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。
【０２４１】
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。
【０２４２】
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。
【０２４３】
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。
【０２４４】
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。
【０２４５】
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。
【０２４６】
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。
【０２４７】
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。
【０２４８】
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。
【０２４９】
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。
【０２５０】
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。
【０２５１】
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。
【０２５２】
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。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。
【０２５３】
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。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。
【０２５４】
前記塩析／融着段階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６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。
【０２５５】
【表６】

【０２５６】
〔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。
【０２５７】
評価１
１．画像評価
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、クリーニング補助ブラシローラー採用プロセスを有する）をベースとした評価機を用い、該複写機に感光体１〜１９を搭載し、現像剤１と組み合わせて評価した。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中性紙に複写して行った。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２０万枚のコピー行い、ハーフトーン、ベタ白画像、ベタ黒画像を評価した。
【０２５８】
評価項目及び評価基準
画像濃度（マクベス社製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）
◎：１．２以上：良好
○：０．８〜１．２未満：実用上問題ないレベル
×：０．８未満：実用上問題となるレベル
鮮鋭性（２０万枚コピー終了後に文字画像で鮮鋭性を評価）
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。
【０２５９】
◎：３ポイント、５ポイントとも明瞭であり、容易に判読可能
○：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
×：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
トナーの転写性（２０万枚コピー終了後、感光体上に６０ｍｇ／ｃｍ^２の画像を形成し、転写紙に転写された単位面積当たりの付着量（ｆｍｇ／ｃｍ^２）を測定し、以下の計算により転写率を算定した。）
トナーの転写率＝（ｆ／６０）×１００
◎：トナーの転写率８５％以上：良好
○：トナーの転写率６５〜８４％：実用上問題ないレベル
×：トナーの転写率６４％以下：実用上問題となるレベル
クリーニング性（１０万及び２０万コピー終了後に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）
◎：２０万枚ですり抜け発生なし
○：１０万枚まですり抜け発生なし
×：１０万枚未満ですり抜け発生
耐傷性（２０万枚のコピー画像を全数検査し、分離爪による画像傷の発生の有無の確認、及び感光体表面の分離爪による傷の発生の有無をコピー１万枚毎に検査した。）
◎：感光体表面にもコピー画像にも分離爪による傷の発生なし
○：感光体表面には弱い傷発生があるが、コピー画像には分離爪による傷の発生なし
×：感光体表面にははっきりした傷発生があり、コピー画像にも分離爪による傷の発生あり
その他評価条件
尚、上記デジタル複写機Ｋｏｎｉｃａ７０７５を用いたその他の評価条件は下記の条件に設定した。
【０２６０】
帯電条件
帯電器；スコロトロン帯電器、初期帯電電位を−５００Ｖ
露光条件
露光部電位を−５０Ｖにする露光量に設定。
【０２６１】
露光ビーム：ドット密度４００ｄｐｉの像露光を行った。レーザビームスポット面積：０．８×１０^−９ｍ^２
現像条件
ＤＣバイアス；−４００Ｖ
現像剤は、前記した現像剤を使用した。
【０２６２】
転写条件
転写極；コロナ帯電方式
分離条件
図２〜図４で説明した分離爪ユニットの分離手段を用いた。
【０２６３】
分離爪の材質：ベースの材質がポリアミドイミド（ＰＡＩ）であり、それにポリテトラフルオロエチレン（ＰＴＦＥ）をコートしたもの
感光体への当接荷重：５．６ｍＮ
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（ｇ／ｃｍ）となるように重り荷重方式で当接した。
【０２６４】
２．クリープ率の測定
使用機器：フィッシャースコープＨ１００Ｖ（微小硬さ測定装置）（株）フィッシャー・インストルメンツ社製
使用圧子：ダイアモンド　ビッカース圧子
負荷条件：４ｍＮ／ｓｅｃの速度で有機感光体の表面からビッカース圧子を押し込む
負荷時間：５ｓｅｃ
保持時間：５ｓｅｃ
除荷条件：負荷と同じ速度で負荷を除く
測定試料
アルミ平板上に前記した感光体と同様に中間層、電荷発生層、第一電荷輸送層、第二電荷輸送層を設け、同じ条件で乾燥させた試料を作製した試料をＨ１００Ｖ機に固定し、試料に対して垂直にビッカース圧子を押し込み測定。
【０２６５】
測定は圧子負荷（５ｓｅｃ）、荷重保持（５ｓｅｃ：この間の変形量の割合がクリープ率）、除荷の手順で行う。
【０２６６】
クリープ率の求め方
ＣＨＵ（クリープ率）＝｛（ｈ２−ｈ１）／ｈ１｝×１００（％）
ｈ１：負荷荷重（２０ｍＮ）に達した時（負荷開始から５秒後）の押し込み深さ
ｈ２：保持（５ｓｅｃ）後の押し込み深さ
評価結果を表７に示した。
【０２６７】
【表７】

【０２６８】
電荷輸送層に立体異性体混合物の電荷輸送物質を用い、電荷輸送層の膜厚及びクリープ率が本発明の範囲にある感光体１〜４及び７〜１１、１４〜１８は画像濃度、トナーの転写性、鮮鋭性、クリーニング性、耐傷性の各評価項目において、良好な特性を示しているが、本発明外の感光体５（クリープ率：３．６７）ではクリーニング性、耐傷性が劣り、感光体６（クリープ率：０．７５）では、画像濃度、クリーニング性が低下し、その結果鮮鋭性が劣化している。又、感光体１２（電荷輸送層の膜厚：４μｍ）は、帯電電位が設定値の−５００Ｖに達せず、画像濃度が低下し、鮮鋭性が劣化しており、感光体１３（電荷輸送層の膜厚：１６μｍ）でも鮮鋭性が劣化している。又、公知の立体異性体構造を有しない電荷輸送物質を用いた場合（感光体１９）は、トナーのクリーニングが劣り、使用中に表面にフィルミングが発生し、鮮鋭性が劣化しやすい。
【０２６９】
評価２（画像形成方法の評価：感光体と現像剤の組み合わせ評価）
上記で得られた感光体２〜７、１１、１２、１３と現像剤２〜１６を表８のように組み合わせ（組み合わせＮｏ．１〜２３）、デジタル複写機Ｋｏｎｉｃａ７０７５をベースにした評価機を用いて、評価１で行ったと同様の画像評価を行った。その結果を表８に示す。
【０２７０】
【表８】

【０２７１】
表８の結果より、本発明の有機感光体（電荷輸送層が立体異性体混合物の電荷輸送物質を含有し、電荷輸送層の膜厚が５〜１５μｍで且つクリープ率（ビッカース圧子を荷重２０ｍＮで押し込んだ時のクリープ率）が１％以上３．５％未満である有機感光体：Ｎｏ．２又はＮｏ．３、４、７、１１）を用い、トナーの形状係数、形状係数の変動係数等の少なくとも１つが本発明のトナー（Ｎｏ．２〜１４）の組み合わせ（組み合わせＮｏ．１〜１３、１６、１７、２０、２１）は画像濃度、鮮鋭性、トナーの転写性、クリーニング性、耐傷性の評価も良好である。特に、感光体２又は３を用い、トナー粒子の形状係数の変動係数、個数粒度分布における個数変動係数、形状係数、角のないトナー粒子の個数割合、トナー粒子の粒度分布（Ｍ＝ｍ_１＋ｍ_２）の全ての条件が本発明内であるトナーとの組み合わせ（組み合わせＮｏ．１、２、１６）は、最も良好な評価結果を示している。一方、トナーが前記本発明の全ての条件を備えたトナー２を用いても、感光体が本発明外の組み合わせ（組み合わせＮｏ．１８、１９、２２、２３）は、画像濃度、クリーニング性、耐傷性等が低下し、その結果鮮鋭性が低下している。又、トナーが本発明外の組み合わせ（組み合わせＮｏ．１４、１５）では、感光体が本発明内のものであってもトナーの転写性、クリーニング性、耐傷性が低下し、鮮鋭性が劣化している。
【０２７２】
【発明の効果】
実施例からも明らかなように、本発明の構成を有する有機感光体を用いることにより、高温高湿下で、多数枚のコピーを行ってもトナーの転写性、残留トナークリーニング性を改善すると同時に、耐傷性を改善し、鮮鋭性の良好な電子写真画像を作製することができる。
【図面の簡単な説明】
【図１】本発明の画像形成装置の機能が組み込まれた概略図である。
【図２】分離爪ユニットの平面図である。
【図３】分離爪ユニットの側面図である。
【図４】分離爪の側面図である。
【図５】（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。
【符号の説明】
１　画像形成装置
２１　感光体
２１Ａ　有機感光体
２１Ｂ　ＨＣ有機感光体
２２　帯電手段
２３　現像手段
２４　転写極
２５　分離極
２６　クリーニング手段
３０　露光光学系
４５　転写搬送ベルト装置
５０　定着手段
２５０　分離爪ユニット
２５１　基板
２５２　分離爪
２５５　トルクバネ
２６０　当接荷重切換手段
２６１　当接解除板
２６２　シャフト
２６５　直流ソレノイド
２７１　固定基板
２７１Ａ　ガイド
２７２　ステッピングモータ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an organic photoreceptor used in the field of copying machines and printers, and an image forming method, an image forming apparatus, and a process cartridge using the organic photoreceptor.
[0002]
[Prior art]
In recent years, organic photoconductors have been widely used as electrophotographic photoconductors. Organic photoreceptors have advantages over other photoreceptors such as easy development of materials corresponding to various exposure light sources from visible light to infrared light, selection of materials without environmental pollution, and low manufacturing cost. However, disadvantages include poor mechanical strength and poor chemical durability, deterioration of the electrostatic characteristics of the photoreceptor at the time of printing a large number of sheets, and generation of surface scratches.
[0003]
That is, since an electrical or mechanical external force is directly applied to the surface of an organic photoreceptor (hereinafter, also simply referred to as a photoreceptor) by a charging unit, a developing unit, a transfer unit, a cleaning unit, and the like, durability against these is required. You.
[0004]
Specifically, the photoreceptor is required to have durability against abrasion and scratches on the surface of the photoreceptor due to friction, active oxygen such as ozone generated during corona charging, surface deterioration due to nitrogen oxides, and the like.
[0005]
In order to solve the problems of mechanical and chemical durability as described above, the organic photoreceptor has a layer structure of a charge generation layer and a charge transport layer, and the charge transport layer of the surface layer has high strength and high charge. In many cases, a uniform layer hardly permeates the active gas and the thickness of the charge transport layer is set to be larger than 20 μm.
[0006]
Further, as another approach, a technique of providing a high-strength protective layer on the surface of the photoreceptor has been studied. For example, JP-A-6-118681 reports that a curable silicone resin is used as a protective layer of a photoreceptor. However, the method of thickening the charge transport layer and the method of providing a high-strength protective layer as described above have a problem that carriers generated in the charge generation layer diffuse laterally before reaching the surface, and sharpness and the like are disadvantageous. Problem. In the field of digital copiers, there is a growing demand for higher image quality, and high-resolution image formation is being studied. In this way, a good electrostatic latent image can be obtained with a layer structure or protective layer that easily causes carrier diffusion. Can not.
[0007]
In order to faithfully reproduce image information as an electrostatic latent image, it is necessary to ensure a sufficient potential contrast between the exposed and unexposed portions. This is because diffusion of carriers until the generated carriers reach the surface charge is performed. It is important to control. In the Journal of the Imaging Society of Japan, Vol. 38, No. 4, page 296, deterioration of a latent image in a high-density image is caused by an increase in the ratio D / μ between the diffusion constant (D) and the drift mobility (μ) of the charge transport layer. It is described that the effect of diffusion to the latent image cannot be ignored, and that the latent image degradation increases as the thickness of the charge transport layer increases. However, the organic photoreceptors that have been put to practical use have a large thickness loss due to abrasion of a cleaning blade or the like, and designing the thickness of the photosensitive layer such as the charge transport layer to 20 μm or less further reduces the durability of the photoreceptor. Was not preferred.
[0008]
Heretofore, an organic photoreceptor having a thin charge transport layer and preventing diffusion of an electrostatic latent image has already been proposed in JP-A-5-119503. However, these proposed organic photoreceptors have not been able to provide a sufficient solution to the requirements for durability and high image quality of the photoreceptor.
[0009]
In order to form a high-resolution digital image, it is necessary to accurately attach toner to the electrostatic latent image formed on the surface of the photoreceptor and to accurately visualize the digital dot latent image. That is, in order to form a toner image that faithfully reproduces an electrostatic latent image without scattering toner on the surface of the organic photoreceptor, it is necessary to ensure that no foreign matter adheres to the surface of the organic photoreceptor, It is important that the properties are not roughened.
[0010]
Conventionally, in order to improve the quality of digital images, it has been often proposed to use toner having a small particle size or a sharp particle size distribution. Also, if the organic photoreceptor does not have the surface characteristics capable of faithfully reproducing the electrostatic latent image without scattering the toner described above, the effect of reducing the particle size of the toner and improving the particle size distribution cannot be sufficiently utilized. Was found.
[0011]
On the other hand, as a method for improving the abrasion resistance characteristics of the organic photoreceptor, in addition to the above-mentioned protective layer using a curable silicone resin, JP-A-56-117245, JP-A-63-91666 and JP-A-1-205171. In each of the publications, it is described that silica particles are contained in the outermost surface layer of the photoreceptor so that the mechanical strength of the photoreceptor surface can be increased and the durability can be improved. Further, JP-A-57-176557, JP-A-61-117558 and JP-A-3-155558 disclose hydrophobic silica particles obtained by treating the silica particles with a silane coupling agent or the like. It is described that the photoreceptor can be contained in the outermost surface layer to increase the mechanical strength of the photoreceptor and to impart lubricity to obtain a photoreceptor with higher durability.
[0012]
However, these abrasion resistance improving techniques tend to reduce image quality, particularly sharpness, when images are repeatedly formed and a large number of copied images are formed.
[0013]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and to form an accurate electrostatic latent image with small blur upon image exposure, and to visualize the electrostatic latent image as a toner image faithfully. To provide an organic photoreceptor capable of maintaining high image quality even under severe environmental conditions such as high temperature, high humidity, and low temperature and low humidity. An object of the present invention is to provide an organic photoreceptor, and to provide an image forming method, an image forming apparatus using the photoreceptor, and a process cartridge used in the image forming apparatus.
[0014]
[Means for Solving the Problems]
We have examined the above problems and found that the organic photoreceptor can be used as a charge generation layer and a charge transport layer in order to improve the sharpness and abrasion resistance of organic photoreceptors that repeatedly copy and print many sheets. Separate configuration, reducing the total thickness of the charge transport layer forming the surface layer, and at the same time, the viscoelastic properties of the surface layer make it difficult for foreign substances to adhere, and the surface is hardly scratched and roughened even after repeated use. The present invention has been found that it is necessary to provide abrasion resistance characteristics.
[0015]
Further, when an electrophotographic image is formed by using such an organic photoreceptor and a toner having a uniform shape coefficient and particle size distribution, a high-quality electrophotographic image with more excellent sharpness can be obtained.
[0016]
That is, the object of the present invention is achieved by having the following configuration.
1. At least one charge transport layer having a total thickness of 5 to 15 μm on the charge generation layer, the uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and a creep rate (Creep ratio when Vickers indenter is pushed in with a load of 20 mN) is 1% or more and less than 3.5%.
[0017]
2. 2. The organophotoreceptor according to item 1, wherein the content of the maximum component of the stereoisomer is 25 to 80% by mass.
[0018]
3. 3. The organic photoreceptor according to the above item 1 or 2, wherein the uppermost charge transport layer contains fine particles having a number average particle diameter of 10 nm or more and less than 100 nm.
[0019]
4. 4. The organic photoconductor according to any one of items 1 to 3, wherein the uppermost charge transport layer is a surface layer.
[0020]
5. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing process, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, the coefficient of variation of the shape coefficient of the toner particles in the developing step is 16% or less, the coefficient of number variation in the number particle size distribution is 27% or less, and the organic photoreceptor has at least one layer on the charge generation layer. It has a charge transport layer having a thickness of 5 to 15 μm, the uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and has a creep rate (when a Vickers indenter is pushed in with a load of 20 mN). (Creep ratio) of 1% or more and less than 3.5%.
[0021]
6. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing process, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, the toner in the developing step contains at least 65% by number of toner particles having a shape factor in the range of 1.2 to 1.6, and the organic photoreceptor has a total film thickness of at least one layer on the charge generation layer. Has a charge transport layer of 5 to 15 μm, the uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and has a creep rate (creep when a Vickers indenter is pushed in with a load of 20 mN). %) Is 1% or more and less than 3.5%.
[0022]
7. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing process, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, when the particle size of the toner particles in the developing step is D (μm), the natural logarithm InD is plotted on the horizontal axis, and the horizontal axis is the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The relative frequency (m) of the toner particles included in the mode₁) And the relative frequency (m) of the toner particles contained in the class with the highest frequency next to the mode.₂), The organic photoreceptor has at least one charge transport layer having a total film thickness of 5 to 15 μm on the charge generation layer, and the uppermost charge transport layer has An image containing a charge transporting substance of a mixture of two or more stereoisomers, and having a creep rate (creep rate when a Vickers indenter is pushed in with a load of 20 mN) of 1% or more and less than 3.5%. Forming method.
[0023]
8. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing process, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, the toner in the developing step contains 60% by number or more of toner particles having no corners, and the organic photoreceptor has at least one charge transport layer having a total film thickness of 5 to 15 μm on the charge generation layer. The uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and has a creep rate (creep rate when a Vickers indenter is pushed in with a load of 20 mN) of 1% to 3.5%. Image forming method.
[0024]
9. 9. The image forming method according to any one of the items 5 to 8, wherein the number average particle diameter of the toner particles in the developing step is 3 to 8 μm.
[0025]
10. The formation of the electrostatic latent image is performed when the exposure spot area is 2 × 10^-9(M²The image forming method according to any one of the above items 5 to 9, wherein the image forming method is performed by exposure of the following exposure beam.
[0026]
11. An image forming apparatus which forms an electrophotographic image using the image forming method according to any one of the above items 5 to 10.
[0027]
12. The organic photoreceptor according to any one of the above items 1 to 4, wherein any one of a charging unit, an image exposing unit, a developing unit, and a cleaning unit is integrally combined, and is freely inserted into and removed from the image forming apparatus. A process cartridge characterized by being designed.
[0028]
That is, the organic photoreceptor of the present invention is an organic photoreceptor obtained by laminating a charge generation layer and a charge transport layer having a total thickness of at least one layer of 5 to 15 μm on a conductive support in this order. The transport layer contains a charge transport material of a mixture of two or more stereoisomers, and has a creep rate (creep rate when a Vickers indenter is pushed in with a load of 20 mN) of 1% or more and less than 3.5%. And
[0029]
Since the organic photoreceptor of the present invention has the above-described configuration, filming due to adhesion of toner or paper powder to the surface layer is prevented, and even when used repeatedly, character dust and toner scattering do not occur. An image having characteristics and good sharpness can be produced.
[0030]
Further, the image forming method of the present invention develops an electrostatic latent image on the organic photoreceptor having the above-described configuration using a toner as described below, thereby obtaining a high-quality electrophotographic image having good sharpness. Can be provided for a long time.
[0031]
That is, in the uppermost charge transporting layer of the present invention, by using a mixture of stereoisomers as the charge transporting material, the compatibility between the binder of the charge transporting layer and the charge transporting material becomes good, and the film quality of the charge transporting layer and the electron transport property are improved. This is presumably because the photographic characteristics are improved, the adhesion between the photoreceptor and the toner is reduced, and the transferability and cleaning property of the toner are improved. As a result, reduction in image density and sharpness and occurrence of image defects are prevented.
[0032]
The content of the maximum component in the stereoisomer mixture is preferably from 25 to 80% by mass. When the content of the maximum component is more than 80% by mass, the dispersibility of the charge transporting substance is deteriorated, the image density is lowered, and image defects such as white spots and black spots are easily generated. On the other hand, if it is less than 25% by mass, the stability of the electrophotographic characteristics is impaired, and the image density and resolution tend to be reduced. Most preferably, the content of the largest component in the stereoisomer mixture is 33 to 75% by mass.
[0033]
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 high molecular weight charge transporting substance, the film quality of the charge transporting layer can be improved, and the effect of the present invention described above can be made more remarkable.
[0034]
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 changing the configuration of atoms or atomic groups therein.
[0035]
Further, the organic photoreceptor of the present invention has a property that the charge transport layer on the surface has a certain plastic deformation (1% or more and less than 3.5%) property with respect to a constant load indenter (load 20 mN) applied from the surface. The organic photoreceptor has a feature.
[0036]
By configuring the charge transport layer having such viscoelastic properties as the surface layer, the transferability of the toner as described above and the cleaning performance of the residual toner are improved, and at the same time, the scratch resistance is improved, and a stable surface is always provided. An electrophotographic image having excellent sharpness and the like can be formed without disturbing the toner image formed and developed by the development.
[0037]
The surface layer having the viscoelastic property as described above uses the high-elasticity polycarbonate as a binder resin in the uppermost charge-transporting layer, and at the same time, contains the charge-transporting substance of the stereoisomer mixture, so that the binder has a high elasticity. This can be achieved by using a charge transport layer maintaining the above as a surface layer. In addition, it is preferable that such a charge transport layer has two or more charge transport layers, and the uppermost charge transport layer has the above-described configuration.
[0038]
Examples of the high elasticity polycarbonate preferably used in the present invention include the following polycarbonates.
[0039]
Embedded image

[0040]
The mixing ratio of the charge transporting substance to the polycarbonate in the stereoisomer mixture is preferably 0.5 to 3.0, more preferably 0.8 to 2.0 in terms of the mass ratio of the charge transporting substance 1 to the polycarbonate. This ratio varies with the type of charge transport material or polycarbonate, or with the presence of other additives, and is not absolute.
[0041]
The creep rate of the present invention is 1% or more and less than 3.5%, but is more preferably 2.0% or more and 3.2% or less.
[0042]
It is more preferable to mix hydrophobic inorganic particles having a number average primary particle size of 10 nm or more and less than 100 nm. The number average particle diameter of the hydrophobic inorganic particles is more preferably 10 nm or more and 90 nm or less, most preferably 10 nm or more and less than 50 nm. When the number average primary particle diameter of the inorganic particles contained in the surface layer is less than 10 nm or more than 100 nm, the viscoelastic properties are hardly obtained, and the above-mentioned improvement effect is hardly obtained.
[0043]
The inorganic particles having a size of 10 nm or more and less than 100 nm used in the present invention include silica, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped oxide. Fine particles such as tin and zirconium oxide can be preferably used. Among them, silica, particularly hydrophobic silica whose surface is hydrophobized, is preferable from the viewpoints of cost, adjustment of particle size, ease of surface treatment, and the like.
[0044]
The number average primary particle size of the inorganic particles of the present invention is magnified 10,000 times by transmission electron microscopy, randomly observes 300 particles as primary particles, and measures the number average particle size of Feret diameter by image analysis. Is calculated.
[0045]
The hydrophobicity of the above-mentioned hydrophobic silica is preferably 50% or more in terms of the degree of hydrophobicity indicated by a measure of methanol wettability (methanol wettability). If the degree of hydrophobicity is less than 50%, a large amount of hydroxyl groups remaining on the silica surface will bind to the binder resin, and the creep rate will be small, and the photoreceptor surface will be apt to be moistened, and the residual potential will increase. Cleaning failure is also likely to occur. A more preferred degree of hydrophobicity is 65% or more, most preferably 70% or more.
[0046]
The methanol wettability representing the degree of hydrophobicity is to evaluate the wettability of the silica fine powder with methanol. The wettability is measured by the following method. 0.2 g of the silica fine powder to be measured is added to 50 ml of distilled water placed in a 250 ml beaker and stirred. Next, methanol is slowly added dropwise from a burette whose tip is immersed in the liquid until the whole silica fine powder is wet with stirring. Assuming that the amount of methanol necessary for completely wetting the silica fine powder is a (ml), the degree of hydrophobicity is calculated by the following equation (1).
[0047]
Formula (1) degree of hydrophobicity = a / (a + 50) × 100
The hydrophobic silica can be obtained by hydrophobizing silica powder produced by a known wet method or dry method. In particular, a so-called fumed silica produced by a dry method (vapor phase oxidation of a silicified halogen compound) treated with a hydrophobizing agent is preferable because it has few moisture adsorption sites. This is manufactured by a conventionally known technique. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.
[0048]
SiCl₄+ 2H₂+ O₂→ SiO₂+4 HCl
In this production step, for example, a composite fine powder of silica and another metal oxide can be obtained by using another metal halide such as aluminum chloride or titanium chloride together with a silicon halide.
[0049]
Hydrophobization treatment of silica powder is performed by spraying a hydrophobizing agent solution dissolved with alcohol or the like on a silica fine powder dispersed in a cloud shape by stirring or by contacting a vaporized hydrophobizing agent. A conventionally known method such as a dry treatment in which a silica powder is dispersed in a solution and a wet treatment in which a hydrophobic treatment agent is dropped and adhered thereto is applied.
[0050]
Known compounds can be used as the hydrophobizing agent, and specific examples are shown below. These compounds may be used in combination.
[0051]
Examples of the titanium coupling agent include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate and bis (dioctyl pyrophosphate) oxyacetate titanate.
[0052]
As the silane coupling agent, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β-vinylbenzylamino Ethyl-N-γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyl Examples include trimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane.
[0053]
Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, and amino-modified silicone oil.
[0054]
These hydrophobizing agents are preferably coated by adding 1 to 40% by mass based on the silica powder, and more preferably 3 to 30% by mass.
[0055]
Further, a hydrogen polysiloxane compound may be used as the surface hydrophobizing agent. The hydrogen polysiloxane compound having a molecular weight of 1,000 to 20,000 is generally easily available and has a good black spot prevention function. In particular, when methyl hydrogen polysiloxane is used for the final surface treatment, a good effect can be obtained.
[0056]
In the present invention, the hydrophobic layer subjected to the hydrophobic treatment is contained in the surface layer of the organic photoreceptor together with the binder. The proportion of the silica particles in the surface layer is 1 to 20% by mass, preferably 2 to 15% by mass, based on the binder. , Most preferably from 2 to 10% by weight. If it exceeds 20% by mass, the residual potential increases, the image density tends to decrease, and the transferability of the toner tends to decrease. On the other hand, if it is less than 1% by mass, poor cleaning and a decrease in wear resistance are likely to occur.
[0057]
In addition, the charge transport layer serving as the surface layer contains a charge transport material of the above-described highly elastic polycarbonate binder resin and a mixture of stereoisomers.In addition, the charge transport layer includes an antioxidant in the binder resin. On the other hand, it is preferable to be present in an amount of 1 to 10% by mass.
[0058]
By selectively adopting the configuration as described above, the charge transport layer having the above-mentioned physical properties of the film can be realized, and the organic photoreceptor having such a surface layer as the charge transport layer can improve the residual toner cleaning property and In addition, the present invention can provide an electrophotographic image having improved scratch resistance and abrasion resistance and excellent sharpness over a long period of time.
[0059]
Hereinafter, the configuration of the organic photoconductor applied to the present invention will be described.
In the present invention, the organic photoreceptor refers to 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 all known organic photoconductors, such as a photoconductor composed of an organic charge generating substance or an organic charge transport substance, and a photoconductor composed of a polymer complex having a charge generation function and a charge transport function.
[0060]
The charge transport layer of the present invention means a layer having a function of transporting charge carriers generated in the charge generation layer by light exposure to the surface of the organic photoreceptor. It can be confirmed by laminating the layer and the charge transport layer on a conductive support and detecting photoconductivity.
[0061]
The layer constitution of the organic photoreceptor of the present invention basically comprises a photosensitive layer of a charge generation layer and a charge transport layer on a conductive support. Most preferably, the photosensitive layer is composed of a charge generation layer and a plurality of charge transport layers, the uppermost layer contains a charge transport material of a mixture of two or more stereoisomers of the present invention, and has a creep rate (Vickers indenter). Of the charge transport layer having a characteristic of 1% or more and less than 3.5%.
[0062]
Hereinafter, a specific configuration of the photoconductor used in the present invention will be described.
Conductive support
As the conductive support used in the photoreceptor of the present invention, a sheet-shaped or cylindrical conductive support is used.
[0063]
The cylindrical conductive support of the present invention means a cylindrical support required to be able to form an image endlessly by rotation, and has a straightness of 0.1 mm or less and a runout of 0.1 mm or less. Certain conductive supports are preferred. Exceeding the ranges of straightness and runout makes it difficult to form a good image.
[0064]
As a material for the conductive support, 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 / plastic drum coated with a conductive substance can be used. The conductive support has a specific resistance of 10 at room temperature.³Ωcm or less is preferable.
[0065]
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, the sulfuric acid concentration is preferably 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 preferably 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.
[0066]
Middle class
In the present invention, it is preferable to provide the above-mentioned intermediate layer having a barrier function between the conductive support and the photosensitive layer.
[0067]
The intermediate layer of the present invention preferably contains titanium oxide in the binder resin having a small water absorption. The average particle diameter of the titanium oxide particles is preferably in the range of 10 nm or more and 400 nm or less as a number average primary particle diameter, and more preferably 15 nm to 200 nm.
If it is less than 10 nm, the effect of preventing the occurrence of moire by the intermediate layer is small. On the other hand, if it is larger than 400 nm, sedimentation of the titanium oxide particles in the coating liquid for the intermediate layer tends to occur, and as a result, the uniform dispersibility of the titanium oxide particles in the intermediate layer is poor, and black spots tend to increase. The coating solution for the intermediate layer using titanium oxide particles having a number average primary particle diameter in the above range has good dispersion stability, and the intermediate layer formed from such a coating solution has a function of preventing the occurrence of black spots and environmental characteristics. Is good and has cracking resistance.
[0068]
The shape of the titanium oxide particles used in the present invention includes dendritic, needle-like and granular shapes, and the titanium oxide particles having such a shape are, for example, titanium oxide particles, as anatase type, rutile as a crystal type. There are a crystal type and an amorphous type, and any crystal type may be used, or a mixture of two or more crystal types may be used. Among them, the rutile type and granular type are the best.
[0069]
The titanium oxide particles of the present invention are preferably surface-treated, and one of the surface treatments is a plurality of surface treatments, and the last one of the plurality of surface treatments is a reactive organic compound. The surface treatment using a silicon compound is performed. Further, among the plurality of surface treatments, at least one surface treatment performs at least one or more surface treatments selected from alumina, silica, and zirconia, and finally, a surface treatment using a reactive organosilicon compound. Is preferably performed.
[0070]
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 titanium oxide particles. Japanese foods are also included. Further, the surface treatment of the reactive organosilicon compound means to use the reactive organosilicon compound in the treatment solution.
[0071]
In this way, by performing the surface treatment of the titanium oxide particles such as the titanium oxide particles at least twice or more, the surface of the titanium oxide particles is uniformly coated (treated), and the surface-treated titanium oxide particles are transferred to the intermediate layer. In this case, it is possible to obtain a good photoreceptor having good dispersibility of titanium oxide particles such as titanium oxide particles in the intermediate layer and free from image defects such as black spots.
[0072]
Examples of the reactive organosilicon compound include compounds represented by the following general formula (10), but are not limited to the following compounds as long as they are compounds that undergo a condensation reaction with a reactive group such as a hydroxyl group on the surface of titanium oxide.
[0073]
General formula (10)
(R)_n-Si- (X)_4-n
(In the formula, Si represents a silicon atom, R represents an organic group in which carbon is directly bonded to the silicon atom, X represents a hydrolyzable group, and n represents an integer of 0 to 3.)
In the organosilicon compound represented by the general formula (10), examples of the organic group in which carbon represented by R is directly bonded to silicon include alkyl such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, and dodecyl. Groups, aryl groups such as phenyl, tolyl, naphthyl and biphenyl, epoxy-containing groups such as γ-glycidoxypropyl, β- (3,4-epoxycyclohexyl) ethyl, γ-acryloxypropyl, γ-methacryloxypropyl A (meth) acryloyl group, a hydrous group such as γ-hydroxypropyl and 2,3-dihydroxypropyloxypropyl, a vinyl group such as vinyl and propenyl, a mercapto group such as γ-mercaptopropyl, γ-aminopropyl, Amino-containing groups such as N-β (aminoethyl) -γ-aminopropyl, γ-chloropropyl 1,1,1-fluoroalkyl propyl, nonafluorohexyl, halogen-containing groups such as perfluorooctylethyl, other nitro, and cyano-substituted alkyl group. Examples of the hydrolyzable group for X include an alkoxy group such as methoxy and ethoxy, a halogen group, and an acyloxy group.
[0074]
Further, the organosilicon compound represented by the general formula (10) may be used alone or in combination of two or more.
[0075]
When n is 2 or more in the specific compound of the organosilicon compound represented by the general formula (10), a plurality of Rs may be the same or different. Similarly, when n is 2 or less, a plurality of Xs may be the same or different. When two or more organosilicon compounds represented by the general formula (10) are used, R and X may be the same or different between the respective compounds.
[0076]
A preferred reactive organosilicon compound used for the surface treatment is a polysiloxane compound. The polysiloxane compound having a molecular weight of 1,000 to 20,000 is generally easily available, and has a good black spot prevention function.
[0077]
In particular, when methyl hydrogen polysiloxane is used for the final surface treatment, a good effect can be obtained.
[0078]
Photosensitive layer
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.
[0079]
In the organic photoreceptor of the present invention, for example, other phthalocyanine pigments, azo pigments, perylene pigments, azurenium pigments and the like can be used alone or in combination as charge generation substances.
[0080]
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. 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 from 0.1 μm to 2 μm.
[0081]
Charge transport layer
The charge transport layer of the present invention has a structure of one or more charge transport layers. Although the uppermost charge transporting layer has been described above, the charge transporting layers other than the uppermost layer may adopt a known structure of the charge transporting layer.
[0082]
The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses the CTM and forms a film. As other substances, additives such as antioxidants may be contained as necessary.
[0083]
As the charge transporting substance (CTM), a known charge transporting substance (CTM) can be used in addition to the charge transporting substance of the stereoisomer mixture. In particular, in the charge transport layer other than the uppermost layer, for example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transporting substances are usually dissolved in a suitable binder resin to form a layer.
Among these, the CTM that can minimize the increase in residual potential due to repeated use has a high mobility and an ionization potential difference from the combined CGM of 0.5 (eV) or less, and is preferably 0. .30 (eV) or less.
[0084]
The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).
[0085]
The binder resin used for the charge transport layer (CTL) does not matter whether it is a thermoplastic resin or a thermosetting resin. For example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenolic resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and these resins A copolymer resin containing two or more of the repeating unit structures. In addition to these insulating resins, polymer organic semiconductors such as poly-N-vinyl carbazole may be used. Among them, a polycarbonate resin having a small water absorption, good dispersibility of CTM and good electrophotographic properties is most preferable.
[0086]
The ratio of the binder resin to the charge transporting material is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.
[0087]
The total thickness of the charge transport layer (one or more layers, preferably two to three layers, most preferably two layers) is 5 to 15 μm, and preferably 8 to 15 μm. If the film thickness is less than 5 μm, the charging potential tends to be insufficient, and if it exceeds 15 μm, the sharpness tends to deteriorate.
[0088]
Next, the charge transport material of the stereoisomer mixture of the present invention will be described.
The organic photoreceptor of the present invention is characterized in that the uppermost charge transport layer contains a charge transport material of a stereoisomer mixture. The charge transport material of the stereoisomer mixture has a relatively high molecular weight chemical structure, has good compatibility with the binder resin constituting the charge transport layer, and has a creep rate of 1% or more and 35% or more according to the present invention. It is easy to achieve characteristics of less than. Further, an organic photoreceptor which prevents image defects such as white spots and black spots and has good electrophotographic characteristics such as chargeability and sensitivity can be obtained. The content of the maximum component in the stereoisomer mixture is preferably 25 to 80% by mass. When the content of the maximum component is more than 80% by mass, the dispersibility of the charge transporting substance is deteriorated, the image density is lowered, and image defects such as white spots and black spots are easily generated. On the other hand, if it is less than 25% by mass, the types of stereoisomers are large, and it is difficult to obtain stable electrophotographic properties.
[0089]
The effect as described above is as follows. By using the charge transport material of the stereoisomer mixture, the compatibility between the binder of the photosensitive layer, for example, the charge transport layer and the charge transport material is improved, and the film quality and electrophotographic properties of the charge transport layer are improved. However, it is considered that the adhesion between the photoconductor and the toner is reduced, and the transferability and cleaning property of the toner are improved.
[0090]
The molecular weight of the charge transporting substance having a stereoisomer structure is preferably from 500 to 1500, more preferably from 600 to 1,000, and most preferably from 650 to 850. By using such a high molecular weight charge transporting substance, the film quality of the charge transporting layer can be improved, and the effect of the present invention described above can be made more remarkable.
[0091]
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 changing the configuration of atoms or atomic groups therein.
[0092]
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.
[0093]
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.
[0094]
Embedded image

[0095]
In the general formula (1), R¹, R², R³, R⁴, R⁵Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar¹Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar²Represents a substituted or unsubstituted aromatic group.
[0096]
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[0097]
In the general formula (2), R¹, R², R³, R⁴Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar¹Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar²Represents a substituted or unsubstituted aromatic group.
[0098]
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[0099]
In the general formula (3), R¹, R², R³, R⁴Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar¹Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar²Represents a substituted or unsubstituted aromatic group.
[0100]
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[0101]
In the general formula (4), R¹, R², R³Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar¹Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar²Represents a substituted or unsubstituted aromatic group.
[0102]
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[0103]
In the general formula (5), R¹, R², R³Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar¹Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar²Represents a substituted or unsubstituted aromatic group.
[0104]
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[0105]
In the general formula (6), R¹, R²Is a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, respectively. Ar¹Is a hydrogen atom or a substituted or unsubstituted aromatic group, Ar²Represents a substituted or unsubstituted aromatic group.
[0106]
In addition, Ar in the general formulas (1) to (6)¹, Ar²Is preferably a substituted or unsubstituted aromatic group represented by the following general formula (7).
[0107]
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[0108]
In the general formula (7), R⁶~ R¹⁷Is 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.
[0109]
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. Further, any of these compounds can have a stereoisomer structure.
[0110]
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[0111]
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[0112]
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[0113]
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[0114]
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[0115]
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[0116]
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[0117]
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[0118]
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[0119]
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[0120]
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[0121]
On the other hand, the bis- or tributadiene-based 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.
[0122]
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[0123]
In the general formula (8), R₁, R₂, R₃, R₄, R₅, R₆May 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.
[0124]
Embedded image

[0125]
In the general formula (9), R₇~ R₁₃May 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.
[0126]
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.
[0127]
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[0128]
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[0129]
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[0130]
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[0131]
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[0132]
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[0133]
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[0134]
Solvents or dispersion media used for forming layers such as an intermediate layer, a charge generation layer, and a charge transport layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, and acetone. , 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 cello Lube, 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.
[0135]
Next, as a coating processing method for manufacturing an organic photoreceptor, a coating processing method such as dip coating, spray coating, circular amount control type coating or the like is used. It is preferable to use a coating processing method such as spray coating or circular amount control type (a typical example is a circular slide hopper type) coating so as not to dissolve as much as possible and to achieve uniform coating processing. It is most preferable that the protective layer be formed by the above-mentioned circular amount-regulating coating method. The circular amount control type coating is described in detail in, for example, JP-A-58-189061.
[0136]
Further, the present invention employs an image forming method using a toner having a uniform shape coefficient and a sharp particle size distribution as described below in combination with the organic photoreceptor, thereby providing a high-gradation and sharp electrophotographic image. Can be formed.
[0137]
(1) A toner containing 65% by number or more of toner particles having a shape coefficient in a range of 1.2 to 1.6.
If the shape factor is smaller than 1.2, the shape of the toner becomes close to a true sphere, the adhesive strength of the toner to the photoreceptor increases, and cleaning failure tends to occur. On the other hand, when the ratio is more than 1.6, the toner is crushed and easily pulverized, which also causes cleaning failure. That is, a toner containing 65% by number or more, more preferably 70% by number or more of toner particles having a shape coefficient in the range of 1.2 to 1.6 has a good cleaning property and a large amount of toner which is hard to be pulverized. It is a toner that contains, and when used in combination with the photoreceptor of the present invention, enables good cleaning properties and good image formation over a long period of time.
[0138]
(2) A toner containing 50% by number or more of toner particles having no corners
The toner particles having no corners are toner particles having substantially no protrusions on which electric charges are concentrated or protrusions that are easily broken by stress, and the ratio of the toner particles having no corners is 50% by number or more. More preferably, when the content is 70% by number or more, the generation of fine particles is less likely to occur due to the stress with the developer conveying member and the like, and the cleaning failure due to the generation of fine toner can be prevented. By using them together, good cleaning properties and good image formation can be achieved over a long period of time. For this purpose, the proportion of toner particles having no corners is preferably at least 50% by number, and more preferably at least 70% by number.
[0139]
(3) When the particle size of the toner particles is D (μm), the natural logarithm InD is plotted on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. Relative frequency of toner particles contained in the most frequent class (m₁) And the relative frequency (m) of the toner particles contained in the class with the highest frequency next to the mode.₂) Containing at least 70% of the sum (M)
Relative frequency (m₁) And the relative frequency (m₂) Is 70% or more, the toner particles constituting the toner have a sharp particle size distribution, and a stable toner image can be formed. By using them together, good cleaning properties and good image formation can be achieved over a long period of time.
[0140]
(4) A toner having a number variation coefficient of 27% or less in a number particle size distribution of toner particles and a variation coefficient of a shape factor of toner particles of 16% or less.
By using a toner having a variation coefficient of the shape factor of the toner of 16% or less and a variation coefficient of the number in the number particle size distribution of the toner of 27% or less, excellent cleaning performance and fine line reproducibility and high quality image quality can be obtained. Can be formed over a long period of time.
[0141]
The coefficient of variation in the number of toners is 27% or less, and preferably 25% or less.
The variation coefficient of the shape factor of the toner particles is 16% or less, and more preferably 14% or less. As a result, the shape distribution of the toner particles constituting the toner becomes sharp, and a stable toner image can be formed. As a result, when used in combination with the photoreceptor of the present invention, good cleaning properties can be obtained over a long period of time. And good image formation.
[0142]
Further, it is preferable to use a toner in which the number of toner particles having a shape coefficient in the range of 1.2 to 1.6 is 65% by number or more, and the variation coefficient of the shape coefficient is 16% or less. Such a toner has a small adhesive force to the photoreceptor and has good cleaning properties.
[0143]
Also, by controlling the number of toner particles having no corners to 50% by number or more and controlling the number variation coefficient in the number particle size distribution to 27% or less, excellent cleaning performance and fine line reproducibility and high quality image quality can be formed over a long period of time. be able to.
[0144]
The toner preferably has a number average primary particle diameter of 3 to 8 μm. In the case where toner particles are formed by a polymerization method, the particle size can be controlled by the concentration of the coagulant, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself.
[0145]
When the number average particle diameter is 3 to 8 μm, in the fixing step, it is possible to reduce the presence of toner having excessive adhesion to the developer conveying member, toner having low adhesion, and the like. And the transfer efficiency is increased, the halftone image quality is improved, and the image quality of fine lines, dots, and the like is improved.
[0146]
The shape factor of the toner is represented by the following equation, and indicates the degree of roundness of the toner particles.
[0147]
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.
[0148]
The shape factor is determined by taking a photograph of a toner particle enlarged by 2000 times with a scanning electron microscope, and analyzing a photographic image using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on the photograph. Was measured. At this time, the shape factor of the present invention was measured using the above formula using 100 toner particles.
[0149]
In the toner of the present invention, the toner particles having the shape factor in the range of 1.2 to 1.6 are 65% by number or more, preferably 70% by number or more.
[0150]
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, or a method of adding a toner particle in a solvent that does not dissolve a toner to give a swirling flow, etc. However, in the present invention, it is preferable that the shape factor and the like are produced within the scope of the present invention by using a polymerized toner produced by a polymerization method.
[0151]
The variation coefficient of the shape factor of the toner is calculated from the following equation.
Coefficient of variation = [S / K] × 100 (%)
[Where S represents the standard deviation of the shape coefficients of 100 toner particles, and K represents the average value of the shape coefficients. ]
The variation coefficient of the shape factor is preferably 16% or less, more preferably 14% or less. When the variation coefficient of the shape factor is 16% or less, the gap of the transferred toner layer is reduced, the fixing property is improved, and the offset is less likely to occur. Further, the charge amount distribution becomes sharp, and the image quality is improved.
[0152]
In order to uniformly control the shape coefficient of the toner and the variation coefficient of the shape coefficient without a lot variation, in the production process of the polymerized toner, that is, in the process of polymerizing, fusing, and controlling the shape of the resin particles (polymer particles). Alternatively, an appropriate process end time may be determined while monitoring the characteristics of the toner particles (colored particles) being formed.
[0153]
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.
[0154]
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.
[0155]
The number particle size distribution and the number variation coefficient of the toner are measured with a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter Inc.).
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.
[0156]
The number variation coefficient in the number particle size distribution of the toner is calculated from the following equation.
Number variation coefficient = [S / Dn] × 100 (%)
[Where S represents the standard deviation in the number particle size distribution, and Dn represents the number average particle size (μm). ]
The method of controlling the number variation coefficient 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 a liquid, there is a method of separating and collecting toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by controlling a rotation speed by using a centrifugal separator.
[0157]
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.
[0158]
The toner particles having no corners mean toner particles having substantially no protrusions on which electric charges are concentrated or which are easily worn by stress, that is, as shown in FIG. When the major axis of the 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 and the inside is rolled. The case where the toner does not substantially protrude from the outside is referred to as “toner particles having no corners”. “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. 5B and 5C show projected images of toner particles having corners, respectively.
[0159]
The measurement of the toner having no corner was performed 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.
[0160]
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. However, in view of manufacturing cost and energy cost, a polymerized toner by a polymerization method is preferable.
[0161]
For example, in a polymerization toner formed by associating or fusing resin particles, at the fusing stop stage, there are many irregularities on the surface of the fused particles, the surface is not smooth, but the temperature in the shape control step, 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.
[0162]
The toner of the present invention preferably has a number average particle diameter of 3 to 8 μm. In the case where toner particles are formed by a polymerization method, the particle size can be controlled by the concentration of the coagulant, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself.
[0163]
As the polymerized toner preferably used in the present invention, when the particle size of the toner particles is D (μm), the natural logarithm InD is plotted on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the particle size distribution of, the relative frequency (m₁) And the relative frequency (m) of the toner particles contained in the class with the highest frequency next to the mode.₂)) Is preferably 70% or more.
[0164]
Relative frequency (m₁) And relative frequency (m₂When the sum (M) is 70% or more, the dispersion of the particle size distribution of the toner particles is narrowed, and the use of the toner in the image forming step can reliably suppress the occurrence of selective development. .
[0165]
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.
[0166]
〔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 the system to a dispersion treatment with an ultrasonic disperser for one minute.
[0167]
Among the methods for controlling the shape factor, a polymerization toner is preferred because it is simple as a production method and has excellent surface uniformity as compared with a pulverized toner.
[0168]
Polymerized toners are prepared by suspension polymerization or emulsion polymerization of monomers in a liquid to which an emulsion of necessary additives is added to produce fine polymerized particles. It can be produced by a method of adding and associating. A method of preparing by associating with a dispersion liquid such as a release agent and a colorant necessary for the composition of the toner at the time of association, and dispersing toner components such as a release agent and a colorant in a monomer. And then emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.
[0169]
That is, a coloring agent and, if necessary, a release agent, a charge control agent, various kinds of constituent materials such as a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, or the like is used. Various constituent materials are dissolved or dispersed in the polymerizable monomer. 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 having a desired size as a toner by using a homomixer or a homogenizer. Thereafter, the stirring mechanism is moved to a reaction device, which is a stirring blade described below, and heated to cause the polymerization reaction to proceed. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare a toner.
[0170]
Further, as a method of producing the 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 used. 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. When a large amount of water is added, the particle size growth is stopped by adding a large amount of water, and the shape of the particles is controlled by heating and stirring to smooth the surface of the particles. Can be formed. Here, an organic solvent infinitely soluble in water may be added together with the coagulant.
[0171]
The materials and manufacturing method for producing a toner having a uniform shape factor and the like used in the present invention, a reactor for a polymerized toner, and the like are described in detail in JP-A-2000-214629.
《Developer》
The toner used in the present invention may be a one-component developer or a two-component developer, but is preferably a two-component developer.
[0172]
When used as a one-component developer, there is a method in which the toner is used as it is as a non-magnetic one-component developer, but usually, magnetic particles of about 0.1 to 5 μm are contained in toner particles to form a one-component magnetic developer. Used. As a method of containing the same, it is common to make the non-spherical particles contain the same as the coloring agent.
[0173]
Further, it can be used as a two-component developer by mixing with a carrier. In this case, as the magnetic particles of the carrier, conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead are used.
Particularly, ferrite particles are preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 60 μm.
[0174]
The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution analyzer “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
[0175]
The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. Although there is no particular limitation on the resin composition for coating, for example, an olefin resin, a styrene resin, a styrene / acrylic resin, a silicone resin, an ester resin, or a fluorine-containing polymer resin is used. The resin for forming the resin dispersion type carrier is not particularly limited, and a known resin can be used.For example, a styrene acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like can be used. it can.
[0176]
Next, an image forming apparatus using the organic photoreceptor of the present invention will be described.
The image forming apparatus 1 shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B, an image forming unit C, and a transfer paper transport unit D as a transfer paper transport unit. I have.
[0177]
An automatic document feeder for automatically transporting a document is provided above the image reading unit A. The document placed on the document table 11 is separated and transported one by one by a document transport roller 12, and is moved to a reading position 13a. Image is read. The document for which reading of the document has been completed is discharged onto the document discharge tray 14 by the document conveying roller 12.
[0178]
On the other hand, when the image of the original placed on the platen glass 13 is read at a speed v of a first mirror unit 15 including an illumination lamp and a first mirror constituting a scanning optical system, and a V-shaped second image is read. Reading is performed by moving the second mirror unit 16 including the second mirror and the third mirror in the same direction at the speed v / 2.
[0179]
The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 17. The linear optical image formed on the image sensor CCD is sequentially subjected to A / D conversion after being photoelectrically converted into an electric signal (luminance signal), and subjected to processing such as density conversion and filter processing in an image processing unit B. After that, the image data is temporarily stored in the memory.
[0180]
In the image forming unit C, as an image forming unit, a drum-shaped photoconductor 21 serving as an image carrier, a charging unit (also a charging step) 22 for charging the photoconductor 21 on the outer periphery thereof, A potential detecting unit 220 for detecting a surface potential, a developing unit (also a developing step) 23, a transfer conveyor belt device 45 as a transferring unit (also a transferring step), and a cleaning unit (also a cleaning step) 26 for the photoconductor 21. A PCL (pre-charge lamp) 27 as a light removing unit is arranged in the order of operation. On the downstream side of the developing unit 23, there is provided a reflection density detecting unit 222 for measuring the reflection density of the patch image developed on the photoconductor 21. The photoreceptor 21 uses the organic photoreceptor of the present invention and is driven and rotated clockwise in the drawing.
[0181]
After the rotating photoreceptor 21 is uniformly charged by the charging means 22, the exposure optical system 30 as an image exposure means (also an image exposure step) uses an image signal called from the memory of the image processing unit B based on the image signal. Image exposure is performed. The exposure optical system 30 serving as an image exposure means as a writing means uses a laser diode (not shown) as a light emitting light source, and the optical path is bent by a reflection mirror 32 via a rotating polygon mirror 31, an fθ lens 34, and a cylindrical lens 35, and main scanning is performed. The image exposure is performed on the photoconductor 21 at the position Ao, and an electrostatic latent image is formed by the rotation (sub-scan) of the photoconductor 21. In one example of the present embodiment, a character portion is exposed to form an electrostatic latent image.
[0182]
In the image forming method of the present invention, when forming an electrostatic latent image on a photoreceptor, an image exposure is performed with a spot area of 2 × 10^-9m²It is preferable to use the following exposure beam. Even if such a small-diameter beam exposure is performed, the organic photoreceptor of the present invention can faithfully form an image corresponding to the spot area. More preferable spot area is 0.01 × 10^-9~ 1 × 10^-9m²It is. As a result, at 400 dpi (dpi is the number of dots per 2.54 cm) or more, it is possible to achieve extremely excellent image quality for achieving 256 gradations.
[0183]
The spot area of the light beam is defined as the intensity of the light beam being 1 / e of the peak intensity.²It is represented by an area corresponding to the above light intensity.
[0184]
The light beam used includes a scanning optical system using a semiconductor laser, a solid-state scanner such as an LED or a liquid crystal shutter, and the like, and the light intensity distribution also includes a Gaussian distribution and a Lorentz distribution.²The area up to is the spot area.
[0185]
The electrostatic latent image on the photoconductor 21 is subjected to reversal development by the developing unit 23, and a visible toner image is formed on the surface of the photoconductor 21. In the transfer paper transport section D, paper feed units 41 (A), 41 (B), and 41 (C) are provided below the image forming unit as transfer paper storage means in which transfer papers P of different sizes are stored. A manual paper feed unit 42 for performing manual paper feed is provided on the side, and the transfer paper P selected from any of them is fed along a transport path 40 by guide rollers 43 and fed. The transfer paper P is temporarily stopped by a pair of registration rollers 44 that corrects the inclination and deviation of the transfer paper P, and then re-fed, and the conveyance path 40, the pre-transfer roller 43a, the paper supply path 46, and the entry guide The toner image on the photoreceptor 21 is guided by the plate 47 and is transferred onto the transfer paper P while being placed and transported on the transfer transport belt 454 of the transfer transport belt device 45 by the transfer pole 24 and the separation pole 25 at the transfer position Bo. Transfer sheet P is separated from the photosensitive member 21 surface, it is conveyed to the fixing unit 50 by the transfer conveyor belt device 45.
[0186]
The fixing unit (also a fixing step) 50 includes a fixing roller 51 and a pressure roller 52, and heats and presses the transfer sheet P by passing the transfer sheet P between the fixing roller 51 and the pressure roller 52. To fix the toner. The transfer paper P on which the toner image has been fixed is discharged onto the discharge tray 64.
[0187]
The above is a description of a state in which image formation is performed on one side of transfer paper. In the case of duplex copying, the discharge switching member 170 is switched, the transfer paper guide 177 is opened, and the transfer paper P is indicated by a broken arrow. Conveyed in the direction.
[0188]
Further, the transfer paper P is transported downward by the transport mechanism 178, is switched back by the transfer paper reversing unit 179, and the rear end of the transfer paper P is transported into the double-sided copy paper supply unit 130 as the leading end. You.
[0189]
The transfer paper P is moved in the paper feeding direction by a conveyance guide 131 provided in the two-sided copy paper supply unit 130, the transfer paper P is fed again by the paper feed roller 132, and the transfer paper P is guided to the conveyance path 40. .
[0190]
Again, as described above, the transfer paper P is transported in the direction of the photoconductor 21, the toner image is transferred to the back surface of the transfer paper P, and is fixed by the fixing unit 50, and then discharged to the discharge tray 64.
[0191]
FIG. 2 is a plan view of the separation claw unit, and FIG. 3 is a side view of the separation claw unit. Further, as shown in a side view of the separation claw in FIG. 4, the contact load of the separation claw 252 on the organic photoconductor is switched. The nail scratches at the beginning of copying were reduced, and the occurrence of black streaks was prevented.
[0192]
However, if the contact load of the separation claw 252 is too low to reduce nail scratches, the transfer paper P cannot be separated from the organic photoreceptor 21 and JAM occurs, so the contact load needs to be set in a suitable range. There is.
[0193]
Next, the contact load switching means 260 for appropriately switching the contact load of the separation claw 252 to the organic photoconductor 21 will be described.
[0194]
The contact load switching means 260 includes a separation claw 252, a torque spring 255 for urging the separation claw 252, and a contact release plate 261 for contacting the separation claw 252 with the organic photoconductor 21 to adjust or release the contact load. And a rotary type DC solenoid 265 directly connected to a shaft 262 to which it is attached.
[0195]
The separation claw 252 has its rotating shaft 253 pivotally supported by a bearing 254 and is urged by a torque spring 255. The energization of the rotary type DC solenoid 265 is cut off, and the separation claw 252 is directly connected to the DC solenoid 265. When the shaft 262, which is rotatably supported on the shaft 262, is returned by the spring force and rotates, the contact release plate 261 attached to the shaft 262 is lowered, and the separation claw 252 comes into contact with the surface of the organic photoreceptor 21. When the shaft 262 is energized and returns to the original position, the contact release plate 261 is raised to release the contact of the separation claw 252 and release the contact.
[0196]
Further, by switching the voltage applied to the DC solenoid 265 to change the contact pressure between the contact release plate 261 and the separation claw 252, the contact load between the separation claw 252 and the organic photoconductor 21 is reduced. Can be switched.
[0197]
As described above, the operation of switching the contact load of the separation claw 252 on the organic photoconductor 21 in the contact load switching means 260 is performed by switching the voltage applied to the DC solenoid 265. That is, due to the applied voltage value of the DC solenoid 265, the contact pressure applied to the separation claw 252 at the position where the contact release plate 261 contacts the separation claw 252 reduces the urging force of the separation claw 252 by the torque spring 255, and the organic photosensitive member The contact load of the separation claw 252 with respect to 21 can be adjusted to an appropriate predetermined value and switched.
[0198]
The contact load between the separation claw 252 and the surface of the organic photoreceptor 21 is preferably selected from the range of 0.98 to 7.84 mN and set to an appropriate adjustment value.
[0199]
On the other hand, the stepping motor 272 attached to the fixed board 271 meshes with the rack gear 267 attached to the board 251 of the separation claw unit 250 via the gears 273, 274, 275, 276 also attached to the fixed board 271. The substrate 251 can be moved to an arbitrary set position within a range of about 5 mm left and right along the guide 271A of the fixed substrate 271 and can be stopped. In this manner, it is preferable that the contact position between the separation claw 252 and the organic photoreceptor 21 be changed in the width direction so as to avoid the contact in the same width direction for a long time.
[0200]
The organic photoreceptor of the present invention is generally applicable to electrophotographic apparatuses such as an electrophotographic copying machine, a laser printer, an LED printer, and a liquid crystal shutter printer, but is further applied to a display, recording, light printing, plate making and facsimile to which electrophotographic technology is applied. Etc. can be widely applied.
[0201]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the following description, “parts” means “parts by mass”.
[0202]
Synthesis Example 1 (Synthesis Example of Exemplified Compound T20)
[0203]
Embedded image

[0204]
10 g of the compound represented by the above structural formula was dissolved in 32 g of phosphorus oxychloride, heated to 50 ° C., and 22 ml of dimethylformamide was added dropwise little by little (heated 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.
[0205]
Embedded image

[0206]
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 carried out by a conventional method to obtain 3.3 g (81%) of yellow crystals. When this compound was subjected to elemental analysis and mass analysis, the results were as shown in Table 1 below, and it was confirmed that the compound was the exemplary compound T20.
[0207]
Embedded image

[0208]
Elemental analysis (C₅₃H₄₉N)
[0209]
[Table 1]

[0210]
Mass spectrometry (C₅₃H₄₉N)
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.
[0211]
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
[0212]
Embedded image

[0213]
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.
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 T20-5 were prepared.
[0214]
[Table 2]

[0215]
Synthesis Example 2 (Synthesis Example of Exemplified Compound T83)
[0216]
Embedded image

[0219]
10 g of the compound represented by the above structural 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 washings became neutral. 9.25 g (85%) of the bisformyl compound obtained are obtained.
[0218]
Embedded image

[0219]
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 3 below, and it was confirmed that the compound was the exemplary compound T83.
[0220]
Elemental analysis (C₅₆H₄₀N₂)
[0221]
[Table 3]

[0222]
Mass spectrometry (C₅₆H₄₀N₂)
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.
[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 (T83) solvent: n-hexane / dioxane = 10/1
Sample (T83): 3 mg / solvent 10 ml
[0224]
Embedded image

[0225]
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.
T83 having a mixing ratio of cis-cis / cis-trans / trans-trans as shown in Table 4 by using four compounds T83-1, T83c-c, T83ct, and T83t-t and changing the mixing ratio. -2 to T83-5 were prepared.
[0226]
[Table 4]

[0227]
Production of photoconductor 1
Photoconductor 1 was prepared as follows.
[0228]
The surface of a cylindrical aluminum support having a diameter of 100 mmφ and a length of 346 mm was cut to prepare a conductive support having a surface roughness Rz = 1.5 (μm).
<Intermediate layer>
A dispersion having the following composition was diluted twice with the same mixed solvent, allowed to stand overnight, and then filtered (filter; Rigimesh 5 μm filter manufactured by Pall Corporation) to prepare an intermediate layer coating liquid.
[0229]
Polyamide resin CM8000 (Toray) 1 part
Titanium oxide SMT500SAS (manufactured by Teica) 3 parts
Methanol 10 parts
Using a sand mill as a disperser, dispersion was performed for 10 hours in a batch system.
[0230]
Using the above-mentioned coating solution, coating was performed on the support so as to have a dry film thickness of 2 μm.
<Charge generation layer>
Y-type titanyl phthalocyanine (a titanyl phthalocyanine having a maximum peak at 27.2 degrees at a Bragg angle of 2θ (± 0.2) in Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts
Polyvinyl butyral resin (# 6000-C: manufactured by Denki Kagaku Kogyo) 10 parts
T-butyl acetate @ 700 parts
4-methoxy-4-methyl-2-pentanone {300 parts
Was mixed using a sand mill and dispersed 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 0.3 μm.
[0231]
<First charge transport layer>
Charge transporting substance (T20-1) 225 parts
Binder: Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) ¥ 300 parts
Antioxidant (Irganox1010: manufactured by Ciba-Geigy Japan) 6 parts
Dichloromethane 2,000 parts
Silicon oil (KF-54: Shin-Etsu Chemical Co., Ltd.) 1 part
Were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by dip coating to form a first charge transport layer having a dry film thickness of 6 μm.
[0232]
<Second charge transport layer>
Charge transporting substance (T20-1) 225 parts
Binder: polycarbonate (Exemplified polycarbonate PC-1: viscosity average molecular weight 30,000) @ 300 parts
Hydrophobic silica (hydrophobic silica described in Table 5: average particle size 40 nm) 60 parts
Antioxidant (LS2626: manufactured by Sankyo) 6 parts
1,3-dioxolan @ 2000 parts
Silicon oil (KF-54: Shin-Etsu Chemical Co., Ltd.) 1 part
Were mixed and circulated and dispersed in a circulating dispersion apparatus capable of irradiating ultrasonic waves to prepare a surface layer coating liquid. This coating solution is coated on the first charge transport layer by a circular amount control type coating method so as to have a dry film thickness of 4 μm, and is dried at 110 ° C. for 70 minutes. 1 was produced.
[0233]
Production of photoconductors 2 to 19
In the preparation of the photoreceptor 1, the charge transport material of the first and second charge transport layers and the polycarbonate and hydrophobic silica of the second charge transport layer were changed as shown in Table 5, and the total thickness of the charge transport layer was changed to Photoconductors 2 to 19 were prepared in the same manner as photoconductor 1 except that the thickness of one charge transport layer was changed (however, the first charge transport layer was not applied to photoconductor 12).
[0234]
[Table 5]

[0235]
In the table, PC-4 indicates a polycarbonate having the following structure, and T101 indicates a charge transporting material having the following structure.
[0236]
Embedded image

[0237]
A toner used in the present invention and a developer using the toner were prepared.
(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. To this solution, 1.20 kg of Regal 330R (carbon black manufactured by Cabot Corporation) was gradually added, 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”.
[0238]
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”.
[0239]
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”.
[0240]
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”.
[0241]
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.
[0242]
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".
[0243]
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 = 12.7 million, and the weight average particle size was 120 nm.
[0244]
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”.
[0245]
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”.
[0246]
A solution in which 200.7 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in 12.0 liters of ion-exchanged water is referred to as "initiator solution F".
[0247]
A WAX emulsion (polypropylene emulsion having 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 introduction 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.
[0248]
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. Next, a solution in which 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 were previously mixed 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”.
[0249]
In addition, the glass transition temperature of the resin particles in the 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.
[0250]
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”.
[0251]
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”.
[0252]
In a 100-liter SUS reaction vessel equipped with a temperature sensor, a cooling pipe, a nitrogen introduction device, and a particle size and shape monitoring device, the above-prepared latex-A = 20.0 kg, latex-B = 5.2 kg, and colorant Dispersion 1 = 0.4 kg and ion-exchanged water 20.0 kg were added and 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. The diameter was grown. Next, 2.1 liters of pure water was added to stop the particle size growth, and a fused particle dispersion was prepared.
[0253]
In a 5 liter reaction vessel equipped with a temperature sensor, a cooling pipe, and a monitoring device for particle size and shape, 5.0 kg of the above-prepared fused particle dispersion liquid was placed. The shape was controlled by heating and stirring for 5 to 15 hours. 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.
[0254]
In the monitoring of the salting-out / fusion 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. The toners 1 to 16 comprising toner particles having the shape characteristics and the particle size distribution characteristics shown in Table 6 were obtained by arbitrarily adjusting the coefficient of variation.
[0255]
[Table 6]

[0256]
(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.
[0257]
Evaluation 1
1. Image evaluation
An evaluation machine based on Konica 7075 digital copier (having a corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, blade cleaning, cleaning auxiliary brush roller adoption process) manufactured by Konica Corp. was used as the evaluation machine. The photoconductors 1 to 19 were mounted on a machine and evaluated in combination with the developer 1. The cleaning performance and the image evaluation were performed by copying an original image in which a character image having a pixel ratio of 7%, a photograph of a person's face, a solid white image, and a solid black image were each equal to 1/4 on A4 neutral paper. Copying was performed continuously on 200,000 sheets in a high-temperature and high-humidity environment (30 ° C., 80% RH), which is considered to be the severest, and halftone, solid white image and solid black image were evaluated.
[0258]
Evaluation items and evaluation criteria
Image density (measured using Macbeth RD-918. Measured by relative reflection density with the reflection density of paper set to "0")
◎: 1.2 or more: good
：: 0.8 to less than 1.2: no practical problem
×: Less than 0.8: Practically problematic level
Sharpness (Evaluation of sharpness in character images after copying 200,000 sheets)
Three-point and five-point character images were formed and evaluated according to the following criteria.
[0259]
：: 3 points and 5 points are clear and easily legible
：: 3 points are partially unreadable, 5 points are clear and easily readable
×: 3 points almost illegible, 5 points partially or completely illegible
Transferability of toner (after 200,000 copies, 60 mg / cm²Is formed, and the amount of adhesion per unit area transferred to the transfer paper (fmg / cm²) Was measured, and the transfer rate was calculated by the following calculation. )
Toner transfer rate = (f / 60) × 100
：: toner transfer rate of 85% or more: good
：: Toner transfer rate 65 to 84%: level at which there is no practical problem
×: Toner transfer rate of 64% or less: Level that poses a problem in practical use
Cleanability (10 continuous copies on A3 paper after 100,000 and 200,000 copies are completed, and judgment is made based on whether or not cleaning failure has occurred in solid white areas)
◎: No slippage occurred with 200,000 sheets
：: No slippage occurred up to 100,000 sheets
×: Occurrence of slippage with less than 100,000 sheets
Scratch resistance (All copies of 200,000 copies were inspected to determine whether or not image scratches were generated by the separation nails, and whether or not scratches were generated by the separation nails on the photoreceptor surface were inspected every 10,000 copies.)
：: No scratches caused by separation nails on both photoconductor surface and copy image
○: There is a slight scratch on the photoreceptor surface, but no scratch on the copy image due to the separation nail.
×: There is a clear scratch on the surface of the photoreceptor, and there is a scratch on the copy image due to the separation nail.
Other evaluation conditions
The other evaluation conditions using the digital copying machine Konica 7075 were set as follows.
[0260]
Charging conditions
Charger: Scorotron charger, initial charging potential is -500V
Exposure conditions
The exposure amount is set so that the exposure portion potential is -50V.
[0261]
Exposure beam: Image exposure with a dot density of 400 dpi was performed. Laser beam spot area: 0.8 × 10^-9m²
Development conditions
DC bias; -400V
As the developer, the developer described above was used.
[0262]
Transfer conditions
Transfer pole; corona charging method
Separation conditions
The separation means of the separation claw unit described with reference to FIGS.
[0263]
Separating claw material: Polyamideimide (PAI) base material coated with polytetrafluoroethylene (PTFE)
Contact load to photoconductor: 5.6 mN
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 (g / cm) in the counter direction.
[0264]
2. Measuring creep rate
Equipment used: Fischer Scope H100V (microhardness measuring device) manufactured by Fisher Instruments Co., Ltd.
Indenter used: Diamond Vickers indenter
Load condition: Vickers indenter is pushed in from the surface of the organic photoreceptor at a speed of 4 mN / sec.
Load time: 5 sec
Retention time: 5 sec
Unloading conditions: remove the load at the same speed as the load
Measurement sample
An intermediate layer, a charge generation layer, a first charge transport layer, and a second charge transport layer were provided on the aluminum plate in the same manner as the photoreceptor, and a sample prepared by drying under the same conditions was fixed to an H100V machine. Press the Vickers indenter perpendicular to the sample and measure.
[0265]
The measurement is performed by the procedure of indenter load (5 sec), load holding (5 sec: the rate of deformation during this time is the creep rate), and unloading.
[0266]
How to find the creep rate
CHU (creep rate) = {(h2−h1) / h1} × 100 (%)
h1: Depth of indentation when the applied load (20 mN) is reached (5 seconds after the start of loading)
h2: Depression depth after holding (5 sec)
Table 7 shows the evaluation results.
[0267]
[Table 7]

[0268]
Photoconductors 1 to 4 and 7 to 11 and 14 to 18 in which the charge transport layer uses a charge transport material of a stereoisomer mixture and the charge transport layer has a thickness and a creep rate within the range of the present invention are image densities and toner toners. Although excellent characteristics were shown in each evaluation item of transferability, sharpness, cleaning property, and scratch resistance, the cleaning property and scratch resistance of the photoreceptor 5 (creep ratio: 3.67) out of the present invention were poor. In the case of the photoreceptor 6 (creep rate: 0.75), the image density and the cleaning property are reduced, and as a result, the sharpness is deteriorated. In the photoconductor 12 (charge transport layer thickness: 4 μm), the charging potential did not reach the set value of −500 V, the image density decreased, and the sharpness deteriorated. (Film thickness: 16 μm), the sharpness is deteriorated. When a known charge transport material having no stereoisomer structure is used (photoreceptor 19), cleaning of the toner is inferior, filming occurs on the surface during use, and the sharpness tends to deteriorate.
[0269]
Evaluation 2 (Evaluation of image forming method: evaluation of combination of photoconductor and developer)
The photoconductors 2 to 7, 11, 12, and 13 and the developers 2 to 16 obtained above were combined as shown in Table 8 (combinations Nos. 1 to 23), and an evaluation machine based on a digital copying machine Konica 7075 was used. Then, the same image evaluation as performed in Evaluation 1 was performed. Table 8 shows the results.
[0270]
[Table 8]

[0271]
From the results in Table 8, it can be seen that the organic photoreceptor of the present invention (the charge transport layer contains a charge transport material of a mixture of stereoisomers, the thickness of the charge transport layer is 5 to 15 μm, and the creep rate (Vickers indenter is 20 mN with a load of 20 mN). No. 2 or No. 3, 4, 7, 11) having an organic photoreceptor having a creep rate of 1% or more and less than 3.5% when pushed in, and the shape coefficient of toner, the coefficient of variation of shape coefficient, etc. Is a combination of the toner (Nos. 2 to 14) of the present invention (combinations Nos. 1 to 13, 16, 17, 20, and 21), the image density, sharpness, transferability of the toner, cleaning properties, and scratch resistance. Is also good. In particular, using the photoreceptor 2 or 3, the variation coefficient of the shape coefficient of toner particles, the number variation coefficient in the number particle size distribution, the shape coefficient, the number ratio of toner particles without corners, the particle size distribution of toner particles (M = m₁+ M₂The combination with the toner (combinations Nos. 1, 2, and 16) in which all the conditions of ()) are within the present invention shows the best evaluation results. On the other hand, even when the toner 2 satisfying all the conditions of the present invention is used, the combination of the photoconductors other than the present invention (combinations Nos. 18, 19, 22, and 23) has image density, cleaning property, and scratch resistance. Properties and the like, and as a result, sharpness is reduced. Further, when the toner is a combination outside the present invention (combinations Nos. 14 and 15), even if the photoreceptor is within the present invention, the transferability, cleaning property and scratch resistance of the toner are reduced, and the sharpness is deteriorated. ing.
[0272]
【The invention's effect】
As is clear from the examples, by using the organic photoreceptor having the structure of the present invention, the transferability of the toner and the cleaning performance of the residual toner can be improved even when a large number of copies are made under high temperature and high humidity. In addition, it is possible to produce an electrophotographic image having improved scratch resistance and good sharpness.
[Brief description of the drawings]
FIG. 1 is a schematic diagram in which functions of an image forming apparatus of the present invention are incorporated.
FIG. 2 is a plan view of a separation claw unit.
FIG. 3 is a side view of the separation claw unit.
FIG. 4 is a side view of the separation claw.
5A is an explanatory diagram showing a projected image of a toner particle having no corner, and FIGS. 5B and 5C are explanatory diagrams showing a projected image of a toner particle having a corner. FIG.
[Explanation of symbols]
1 Image forming apparatus
21 photoconductor
21A Organic photoreceptor
21B @ HC organic photoreceptor
22 charging means
23 developing means
24mm transfer pole
25 ° separation pole
26 Cleaning means
30 ° exposure optical system
45 ° transfer conveyor belt device
50 ° fixing means
250 separation claw unit
251 substrate
252 separation claw
255 ° torque spring
260 ° contact load switching means
261 Contact release plate
262 shaft
265 ° DC solenoid
271 fixed board
271A Guide
272 stepper motor

Claims (12)

At least one charge transport layer having a total thickness of 5 to 15 μm on the charge generation layer, the uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and a creep rate (Creep ratio when Vickers indenter is pushed in with a load of 20 mN) is 1% or more and less than 3.5%. The organic photoreceptor according to claim 1, wherein the content of the maximum component of the stereoisomer is 25 to 80% by mass. 3. The organic photoreceptor according to claim 1, wherein the uppermost charge transport layer contains fine particles having a number average particle diameter of 10 nm or more and less than 100 nm. The organic photoconductor according to any one of claims 1 to 3, wherein the uppermost charge transport layer is a surface layer. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing process, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, the coefficient of variation of the shape coefficient of the toner particles in the developing step is 16% or less, the coefficient of number variation in the number particle size distribution is 27% or less, and the organic photoreceptor has at least one layer on the charge generation layer. It has a charge transport layer having a thickness of 5 to 15 μm, the uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and has a creep rate (when a Vickers indenter is pushed in with a load of 20 mN). (Creep ratio) of 1% or more and less than 3.5%. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing process, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, the toner in the developing step contains at least 65% by number of toner particles having a shape factor in the range of 1.2 to 1.6, and the organic photoreceptor has a total film thickness of at least one layer on the charge generation layer. Has a charge transport layer of 5 to 15 μm, the uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and has a creep rate (creep when a Vickers indenter is pushed in with a load of 20 mN). %) Is 1% or more and less than 3.5%. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing step, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, when the particle size of the toner particles in the developing step is D (μm), the natural logarithm InD is plotted on the horizontal axis, and the horizontal axis is the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. In the histogram shown, the sum (M) of the relative frequency (m ₁ ) of the toner particles included in the most frequent class and the relative frequency (m ₂ ) of the toner particles included in the class having the second highest frequency after the most frequent class is obtained. 70% or more, wherein the organic photoreceptor has at least one charge transport layer having a total film thickness of 5 to 15 μm on the charge generation layer, and the uppermost charge transport layer has a mixture of two or more kinds of stereoisomers. Contains charge transport material And an image forming method creep rate (creep rate when pushed Vickers indenter with a load 20 mN) is equal to or less than 3.5% at least 1%. Image formation in which the electrostatic latent image formed on the organic photoreceptor is converted into a toner image in a developing process, the toner image is transferred to a transfer material, and the toner remaining on the organic photoreceptor is cleaned using a cleaning blade. In the method, the toner in the developing step contains 60% by number or more of toner particles having no corners, and the organic photoreceptor has at least one charge transport layer having a total film thickness of 5 to 15 μm on the charge generation layer. The uppermost charge transport layer contains a charge transport material of a mixture of two or more stereoisomers, and has a creep rate (creep rate when a Vickers indenter is pushed in with a load of 20 mN) of 1% to 3.5%. Image forming method. 9. The image forming method according to claim 5, wherein the number average particle diameter of the toner particles in the developing step is 3 to 8 [mu] m. Formation of the electrostatic latent image, an image according to any one of claims 5-9, characterized in that the exposure spot area is carried out by exposure of 2 × 10 -9 ^{(m 2)} following exposure beam Forming method. An image forming apparatus that forms an electrophotographic image by using the image forming method according to claim 5. The organic photoreceptor according to claim 1, wherein one of a charging unit, an image exposing unit, a developing unit, and a cleaning unit is integrally combined, and is freely inserted into and removed from the image forming apparatus. A process cartridge characterized by being designed for.

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