JP2004101800A - Electrophotographic photoreceptor, image forming apparatus, image forming method and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which suppresses variation of electrostatic properties and sensitivity properties due to humidity in the case of using a titanyl phthalocyanine pigment or the like and ensures neither fogging nor occurrence of image defects such as black spots and environmental memory and to provide an image forming method using the electrophotographic photoreceptor, an image forming apparatus and a process cartridge. <P>SOLUTION: The electrophotographic photoreceptor has on a conductive support an intermediate layer containing a resin having 0-40 J/g heat of fusion and ≤5 mass% water absorption, a charge generating layer containing a charge generating material having no endothermic peak between 70 and 150°C in differential thermal analysis, and a charge transport layer containing a charge transport material having a triphenylamine structure. <P>COPYRIGHT: (C)2004,JPO

Description

【００４２】
一般式（２）中、Ｒ_１は水素原子、置換又は無置換のアルキル基、Ｘは置換又は無置換の、アルキレン基、２価のシクロアルカンを含む基、２価の芳香族基及びこれらの混合構造を示し、ｌは自然数を示す。
【００４３】
【化２】

【００４４】
一般式（３）中、Ｒ_２、Ｒ_３は各水素原子、置換又は無置換のアルキル基、Ｙ、Ｚは各置換又は無置換の、アルキレン基、２価のシクロアルカンを含む基、２価の芳香族基及びこれらの混合構造を示し、ｍ、ｎは自然数を示す。
【００４５】
前記のごとく、炭素数が７〜３０の繰り返し単位構造は置換又は無置換の、アルキレン基、２価のシクロアルカンを含む基、２価の芳香族基及びこれらの混合構造を有する化学構造等が挙げられるが、これらの中で２価のシクロアルカンを含む基を有する化学構造が好ましい。
【００４６】
本発明のポリアミド樹脂は繰り返し単位構造のアミド結合間の炭素数が７〜３０であるが、好ましくは９〜２５、更には１１〜２０が良い。またアミド結合間の炭素数が７〜３０の繰り返し単位構造が全繰り返し単位構造中に占める比率は４０〜１００モル％、好ましくは６０〜１００モル％、更には８０〜１００モル％が良い。
【００４７】
前記炭素数が７より小だと、ポリアミド樹脂の吸湿性が大きく、電子写真特性、特に繰り返し使用時の電位の湿度依存性が大きく、更に黒ポチ、環境メモリ等が発生しやすい。３０より大であるとポリアミド樹脂の塗布溶媒への溶解が悪くなり、中間層の塗布膜形成に適さない。
【００４８】
又、アミド結合間の炭素数が７〜３０の繰り返し単位構造が全繰り返し単位構造中に占める比率が４０モル％より小さいと、上記効果が小さくなる。
【００４９】
本発明の好ましいポリアミド樹脂としては下記一般式（１）で示される繰り返し単位構造を有するポリアミドが挙げられる。
【００５０】
【化３】

【００５１】
一般式（１）中、Ｙ_１は２価のアルキル置換されたシクロアルカンを含む基、Ｚ_１はメチレン基、ｍは１〜３、ｎは３〜２０を示す。
【００５２】
上記一般式（１）中、Ｙ_１の２価のアルキル置換されたシクロアルカンを含む基は下記化学構造が好ましい。即ち、Ｙ_１が下記化学構造を有する本発明のポリアミド樹脂は、環境メモリ、黒ポチ改善効果が著しい。
【００５３】
【化４】

【００５４】
上記化学構造において、Ａは単結合、炭素数１〜４のアルキレン基を示し、Ｒ_４は置換基で、アルキル基を示し、ｐは１〜５の自然数を示す。但し、複数のＲ_４は同一でも、異なっていても良い。
【００５５】
本発明のポリアミド樹脂の具体例としては下記のような例が挙げられる。
【００５６】
【化５】

【００５７】
【化６】

【００５８】
【化７】

【００５９】
上記具体例中の（）内の％は繰り返し単位構造のアミド結合間の炭素数が７以上の繰り返し単位構造の比率（モル％）を示す。
【００６０】
上記具体例の中でも、一般式（１）の繰り返し単位構造を有するＮ−１〜Ｎ−４のポリアミド樹脂が特に好ましい。
【００６１】
又、本発明のポリアミド樹脂の分子量は数平均分子量で５，０００〜８０，０００が好ましく、１０，０００〜６０，０００がより好ましい。数平均分子量が５，０００以下だと中間層の膜厚の均一性が劣化し、本発明の効果が十分に発揮されにくい。一方、８０，０００より大きいと、樹脂の溶媒溶解性が低下しやすく、中間層中に凝集樹脂が発生しやすく、黒ポチ等の画像欠陥が発生しやすい。
【００６２】
本発明のポリアミド樹脂はその一部が既に市販されており、例えばダイセル・デグサ（株）社製のベスタメルトＸ１０１０、Ｘ４６８５等の商品名で販売されて、一般的なポリアミドの合成法で作製することができるが、以下に合成例の一例を挙げる。
【００６３】
例示ポリアミド樹脂（Ｎ−１）の合成
攪拌機、窒素、窒素導入管、温度計、脱水管等を備えた重合釜にラウリルラクタム２１５質量部、３−アミノメチル−３，５，５−トリメチルシクロヘキシルアミン１１２質量部、１，１２−ドデカンシカルボン酸１５３質量部及び水２質量部を混合し、加熱加圧下、水を留出させながら９時間反応させた。重合物を取り出し、Ｃ^１３−ＮＭＲにより共重合組成を求めたところ、Ｎ−１の組成と一致した。尚、上記合成された共重合のメルトフローインデックス（ＭＦＩ）は（２３０℃／２．１６ｋｇ）の条件で、５ｇ／１０ｍｉｎであった。
【００６４】
本発明のポリアミド樹脂を溶解し、塗布液を作製する溶媒としては、エタノール、ｎ−プロピルアルコール、イソプロピルアルコール、ｎ−ブタノール、ｔ−ブタノール、ｓｅｃ−ブタノール等の炭素数２〜４のアルコール類が好ましく、ポリアミドの溶解性と作製された塗布液の塗布性の点で優れている。これらの溶媒は全溶媒中に３０〜１００質量％、好ましくは４０〜１００質量％、更には５０〜１００質量％が好ましい。前記溶媒と併用し、好ましい効果を得られる助溶媒としては、メタノール、ベンジルアルコール、トルエン、メチレンクロライド、シクロヘキサノン、テトラヒドロフラン等が挙げられる。
【００６５】
又、本発明の中間層には前記したポリアミド樹脂中に一次粒子径が１０〜４００ｎｍの微粒子を含有させることが好ましい。
【００６６】
上記数平均一次粒子径とは、微粒子を透過型電子顕微鏡観察によって１００００倍に拡大し、ランダムに１００個の粒子を一次粒子として観察し、画像解析によってフェレ方向平均径としての測定値である。
【００６７】
このような微粒子を中間層に含有させると画像欠陥の１つであるレーザ光によるモアレを低減したり、中間層のフリーキャリア（導電性支持体等から進入してくる電子やホール）のブロッキング性を高めることは、公知のことであるが、このような微粒子を中間層に含有させた場合、微粒子が湿度を高めやすく、しばしば温湿度環境依存性が大きくなりやすい。本発明では中間層のバインダー樹脂として前記した融解熱０〜４０Ｊ／ｇで、且つ吸水率５質量％以下の樹脂を用いることにより、このような微粒子を含有させた中間層を形成しても、外部の温湿度変化に対しても安定した特性を有する中間層を得ることができ、その結果感光体の電子写真特性が安定し、外部の温湿度変化に対しても安定した特性を有する感光体を得ることができる。
【００６８】
このような微粒子としては、例えば酸化セリウム、酸化クロム、酸化アルミニウム、酸化マグネシウム、酸化ケイ素、酸化錫、酸化ジルコニウム、酸化鉄、酸化チタンなどの酸化物；硫酸カルシウム、硫酸バリウム、硫酸アルミニウムなどの硫酸塩；珪酸カルシウム、珪酸マグネシウムなどの珪酸塩；チッ化ホウ素、チッ化チタンなどのチッ化物；炭化ケイ素、炭化チタン、炭化ホウ素、炭化タングステン、炭化ジルコニウムなどの炭化物；ホウ化ジルコニウム、ホウ化チタンなどのホウ化物などが挙げられるが、本発明の微粒子としては下記に記すＮ型半導性微粒子が好ましい。
【００６９】
Ｎ型半導性粒子とは、導電性キャリアを電子とする性質をもつ微粒子を示す。すなわち、導電性キャリアを電子とする性質をもつことから、該Ｎ型半導性粒子を絶縁性バインダーに含有させた中間層は、基体からのホール注入を効率的にブロックし、また、感光層からの電子に対してはブロッキング性が少ない性質を有する。
【００７０】
前記Ｎ型半導性粒子は、具体的には酸化チタン（ＴｉＯ_２）、酸化亜鉛（ＺｎＯ）、酸化スズ（ＳｎＯ_２）等の微粒子が挙げられるが、本発明では、特に酸化チタンが好ましく用いられる。
【００７１】
本発明の電子写真感光体の中間層に用いられる微粒子の平均粒径は、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以上とすることで中間層によるモアレ発生の防止効果を大きくすることができる。一方、４００ｎｍ以下とすることがで、中間層塗布液のＮ型半導性粒子の沈降が発生を抑え、その結果中間層中のＮ型半導性粒子の均一分散性を向上させ、黒ポチも増加を抑えることができる。数平均一次粒径が前記範囲のＮ型半導性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。
【００７２】
前記微粒子の数平均一次粒径は、例えば酸化チタンの場合、透過型電子顕微鏡観察によって１００００倍に拡大し、ランダムに１００個の粒子を一次粒子として観察し、画像解析によりフェレ径の数平均径として測定値する。
【００７３】
本発明に用いられる微粒子の形状は、樹枝状、針状および粒状等の形状があり、このような形状のＮ型半導性粒子は、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。
【００７４】
本発明に用いられる微粒子は、表面処理されていることが好ましい。これにより、中間層内における微粒子の分散性が良好で、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。
【００７５】
また、本発明に用いられる微粒子は、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が好ましい。これにより、中間層内における微粒子の分散性がより一層良好で、黒ポチ等の画像欠陥をより一層発生させない良好な感光体を得ることができる。
【００７６】
本発明に用いられる微粒子では、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より好ましい。
【００７７】
また、アルミナ、シリカを用いて表面処理を複数回行い、次いで反応性有機ケイ素化合物による表面処理を行うも好ましい。
【００７８】
尚、アルミナ処理、シリカ処理、ジルコニア処理とは微粒子表面にアルミナ、シリカ、或いはジルコニアを析出させる処理を云い、これらの表面に析出したアルミナ、シリカ、ジルコニアにはアルミナ、シリカ、ジルコニアの水和物も含まれる。又、反応性有機ケイ素化合物の表面処理とは、処理液に反応性有機ケイ素化合物を用いることを意味する。
【００７９】
この様に、酸化チタン粒子の様な微粒子の表面処理を行うことにより、微粒子表面が均一に表面被覆（処理）され、該表面処理された微粒子を中間層に用いると、中間層内における酸化チタン粒子等のＮ型半導性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。
【００８０】
なお、前述のアルミナ、シリカの処理は同時に行っても良いが、特にシリカ処理を最初に行い、次いでアルミナ処理を行うことが好ましい。また、アルミナとシリカの処理をそれぞれ行う場合のアルミナ及びシリカの処理量は、アルミナよりもシリカの多いものが好ましい。
【００８１】
前記酸化チタン等の微粒子のアルミナ、シリカ、及びジルコニア等の金属酸化物による表面処理は湿式法で行うことができる。例えば、シリカ、又はアルミナの表面処理を行ったＮ型半導性粒子は以下の様に作製することができる。
【００８２】
Ｎ型半導性粒子として酸化チタン粒子を用いる場合、酸化チタン粒子（数平均一次粒子径：５０ｎｍ）を５０〜３５０ｇ／Ｌの濃度で水中に分散させて水性スラリーとし、これに水溶性のケイ酸塩又は水溶性のアルミニウム化合物を添加する。その後、アルカリ又は酸を添加して中和し、酸化チタン粒子の表面にシリカ、又はアルミナを析出させる。続いて濾過、洗浄、乾燥を行い目的の表面処理酸化チタンを得る。前記水溶性のケイ酸塩としてケイ酸ナトリウムを使用した場合には、硫酸、硝酸、塩酸等の酸で中和することができる。一方、水溶性のアルミニウム化合物として硫酸アルミニウムを用いたときは水酸化ナトリウムや水酸化カリウム等のアルカリで中和することができる。
【００８３】
なお、上記表面処理に用いられる金属酸化物の量は、前記表面処理時の仕込量にて酸化チタン粒子等のＮ型半導性粒子１００質量部に対して、０．１〜５０質量部、更に好ましくは１〜１０質量部の金属酸化物が用いられる。尚、前述のアルミナとシリカを用いた場合も例えば酸化チタン粒子の場合、酸化チタン粒子１００質量部に対して各々１〜１０質量部用いることが好ましく、アルミナよりもシリカの量が多いことが好ましい。
【００８４】
上記の金属酸化物による表面処理の次に行われる反応性有機ケイ素化合物による表面処理は以下の様な湿式法で行うことが好ましい。
【００８５】
即ち、有機溶剤や水に対して前記反応性有機ケイ素化合物を溶解または懸濁させた液に前記金属酸化物で処理された酸化チタンを添加し、この液をセラミックビーズを用いたメディア分散を行うことが好ましい。次にメディア分散後の分散液を濾過後、加熱処理をしながら、減圧乾燥し、表面を有機ケイ素化合物で被覆した酸化チタン粒子を得る。なお、有機溶剤や水に対して酸化チタンを分散させた懸濁液に前記反応性有機ケイ素化合物を添加しても構わない。
【００８６】
尚、本発明において酸化チタン粒子表面が反応性有機ケイ素化合物により被覆されていることは、光電子分光法（ＥＳＣＡ）、オージェ電子分光法（Ａｕｇｅｒ）、２次イオン質量分析法（ＳＩＭＳ）や拡散反射ＦＩ−ＩＲ等の表面分析手法を複合することによって確認することができる。
【００８７】
前記表面処理に用いられる反応性有機ケイ素化合物の量は、前記表面処理時の仕込量にて前記金属酸化物で処理された酸化チタン１００質量部に対し、反応性有機ケイ素化合物を０．１〜５０質量部、更に好ましくは１〜１０質量部が好ましい。表面処理量が上記範囲よりも少ないと表面処理効果が十分に付与されず、中間層内における酸化チタン粒子の分散性等が悪くなる。また、上記範囲を超えてしまうと電気性能を悪化させる結果残留電位上昇や帯電電位の低下を招いてしまう。
【００８８】
本発明で用いられる反応性有機ケイ素化合物としては下記一般式（４）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。
【００８９】
一般式（４）
（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（４）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。
【００９０】
また、一般式（４）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。
【００９１】
また、一般式（４）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（４）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。
【００９２】
ｎが０の化合物例としては下記の化合物が挙げられる。
テトラクロロシラン、ジエトキシジクロロシラン、テトラメトキシシラン、フェノキシトリクロロシラン、テトラアセトキシシラン、テトラエトキシシラン、テトラアリロキシシラン、テトラプロポキシシラン、テトライソプロポキシシラン、テトラキス（２−メトキシエトキシ）シラン、テトラブトキシシラン、テトラフェノキシシラン、テトラキス（２−エチルブトキシ）シラン、テトラキス（２−エチルヘキシロキシ）シラン等が挙げられる。
【００９３】
ｎが１の化合物例としては下記の化合物が挙げられる。
即ち、トリクロロシラン、メチルトリクロロシラン、ビニルトリクロロシラン、エチルトリクロロシラン、アリルトリクロロシラン、ｎ−プロピルトリクロロシラン、ｎ−ブチルトリクロロシラン、クロロメチルトリエトキシシラン、メチルトリメトキシシラン、メルカプトメチルトリメトキシシラン、トリメトキシビニルシラン、エチルトリメトキシシラン、３，３，４，４，５，５，６，６，６−ノナフルオロヘキシルトリクロロシラン、フェニルトリクロロシラン、３，３，３−トリフルオロプロピルトリメトキシシラン、３−クロロプロピルトリメトキシシラン、トリエトキシシラン、３−メルカプトプロピルトリメトキシシラン、３−アミノプロピルトリメトキシシラン、２−アミノエチルアミノメチルトリメトキシシラン、ベンジルトリクロロシラン、メチルトリアセトキシシラン、クロロメチルトリエトキシシラン、エチルトリアセトキシシラン、フェニルトリメトキシシラン、３−アリルチオプロピルトリメトキシシラン、３−グリシドキシプロピルトリメトキシシラン、３−ブロモプロピルトリエトキシシラン、３−アリルアミノプロピルトリメトキシシラン、プロピルトリエトキシシラン、ヘキシルトリメトキシシラン、３−アミノプロピルトリエトキシシラン、３−メタクリロキシプロピルトリメトキシシラン、ビス（エチルメチルケトオキシム）メトキシメチルシラン、ペンチルトリエトキシシラン、オクチルトリエトキシシラン、ドデシルトリエトキシシラン等が挙げられる。
【００９４】
ｎが２の化合物例としては下記の化合物が挙げられる。
ジメチルジクロロシラン、ジメトキシメチルシラン、ジメトキシジメチルシラン、メチル−３，３，３−トリフルオロプロピルジクロロシラン、ジエトキシシラン、ジエトキシメチルシラン、ジメトキシメチル−３，３，３−トリフルオロプロピルシラン、３−クロロプロピルジメトキシメチルシラン、クロロメチルジエトキシシラン、ジエトキシジメチルシラン、ジメトキシ−３−メルカプトプロピルメチルシラン、３，３，４，４，５，５，６，６，６−ノナフルオロヘキシルメチルジクロロシラン、メチルフェニルジクロロシラン、ジアセトキシメチルビニルシラン、ジエトキシメチルビニルシラン、３−メタクリロキシプロピルメチルジクロロシラン、３−アミノプロピルジエトキシメチルシラン、３−（２−アミノエチルアミノプロピル）ジメトキシメチルシラン、ｔ−ブチルフェニルジクロロシラン、３−メタクリロキシプロピルジメトキシメチルシラン、３−（３−シアノプロピルチオプロピル）ジメトキシメチルシラン、３−（２−アセトキシエチルチオプロピル）ジメトキシメチルシラン、ジメトキシメチル−２−ピペリジノエチルシラン、ジブトキシジメチルシラン、３−ジメチルアミノプロピルジエトキシメチルシラン、ジエトキシメチルフェニルシラン、ジエトキシ−３−グリシドキシプロピルメチルシラン、３−（３−アセトキシプロピルチオ）プロピルジメトキシメチルシラン、ジメトキシメチル−３−ピペリジノプロピルシラン、ジエトキシメチルオクタデシルシラン等が挙げられる。
【００９５】
ｎが３の化合物例としては下記の化合物が挙げられる。
トリメチルクロロシラン、メトキシトリメチルシラン、エトキシトリメチルシラン、メトキシジメチル−３，３，３−トリフルオロプロピルシラン、３−クロロプロピルメトキシジメチルシラン、メトキシ−３−メルカプトプロピルメチルメチルシラン等が挙げられる。
【００９６】
また、一般式（４）で表される有機ケイ素化合物は、好ましくは下記一般式（５）で示される有機ケイ素化合物が用いられる。
【００９７】
一般式（５）
Ｒ−Ｓｉ−Ｘ_３
式中、Ｒはアルキル基、アリール基、Ｘはメトキシ基、エトキシ基、ハロゲン基を表す。
【００９８】
一般式（５）で表される有機ケイ素化合物においては、更に好ましくはＲが炭素数４から８までのアルキル基である有機ケイ素化合物が好ましく、具体的な好ましい化合物例としては、トリメトキシｎ−ブチルシラン、トリメトキシｉ−ブチルシラン、トリメトキシヘキシルシラン、トリメトキシオクチルシランが挙げられる。
【００９９】
又、最後の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。
【０１００】
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。
【０１０１】
本発明の酸化チタンの表面処理の他の１つはフッ素原子を有する有機ケイ素化合物により表面処理を施された酸化チタン粒子である。該フッ素原子を有する有機ケイ素化合物による表面処理、前記した湿式法で行うのが好ましい。
【０１０２】
即ち、有機溶剤や水に対して前記フッ素原子を有する有機ケイ素化合物を溶解または懸濁させ、この中に未処理の酸化チタンを添加し、このような溶液をメディア分散し、濾過、加熱処理を施した後に、乾燥し、酸化チタン表面をフッ素原子を有する有機ケイ素化合物で被覆する。なお、有機溶剤や水に対して酸化チタンを分散した懸濁液に前記フッ素原子を有する有機ケイ素化合物を添加しても構わない。
【０１０３】
尚、前記酸化チタン表面がフッ素原子を有する有機ケイ素化合物によって被覆されていることは、光電子分光法（ＥＳＣＡ）、オージェ電子分光法（Ａｕｇｅｒ）、２次イオン質量分析法（ＳＩＭＳ）や拡散反射ＦＩ−ＩＲ等の表面分析装置を用いて複合的に確認することができる。
【０１０４】
本発明に用いられるフッ素原子を有する有機ケイ素化合物としては、３，３，４，４，５，５，６，６，６−ノナフルオロヘキシルトリクロロシラン、３，３，３−トリフルオロプロピルトリメトキシシラン、メチル−３，３，３−トリフルオロプロピルジクロロシラン、ジメトキシメチル−３，３，３−トリフルオロプロピルシラン、３，３，４，４，５，５，６，６，６−ノナフルオロヘキシルメチルジクロロシラン等が挙げられる。
【０１０５】
前記ポリアミド樹脂中に分散されるＮ型半導性粒子の量は、例えば表面処理酸化チタンの場合では、該バインダー樹脂１００質量部に対し、１０〜１０，０００質量部、好ましくは５０〜１，０００質量部である。該表面処理酸化チタンをこの範囲で用いることにより、該酸化チタンの分散性を良好に保つことができ、黒ポチの発生しない、良好な中間層を形成することができる。
【０１０６】
又、本発明の中間層は実質的に絶縁層である。ここで絶縁層とは、体積抵抗が１×１０^８〜１０^１５Ω・ｃｍである。又、本発明の中間層の体積抵抗は好ましくは１×１０^９〜１０^１４Ω・ｃｍ、更に好ましくは、２×１０^９〜１×１０^１３Ω・ｃｍが良い。体積抵抗は下記のようにして測定できる。
【０１０７】

体積抵抗が１×１０^８未満では中間層の電荷ブロッキング性が低下し、黒ポチの発生が増大し、電子写真感光体の電位保持性も劣化し、良好な画質が得られない。一方１０^１５Ω・ｃｍより大きいと繰り返し画像形成で残留電位が増大しやすく、良好な画質が得られない。
【０１０８】
本発明の電子写真感光体の中間層を形成するために作製するために用いる分散溶媒としては、前記したポリアミド樹脂の溶媒と同様なものが適宜用いられる。
【０１０９】
又、上記微粒子以外に、金属酸化物の微粒子も好ましく用いられる。金属酸化物の微粒子としては、例えば酸化セリウム、酸化クロム、酸化アルミニウム、酸化マグネシウム、酸化ケイ素、酸化錫などの酸化物などが挙げられ、これらのうち１種を、又は、必要に応じて２種以上の金属酸化物を用いることが好ましい。又、これらの金属酸化物は、例えばチタンカップリング剤、シランカップリング剤、高分子脂肪酸又はその金属塩等の疎水化処理剤により疎水化されたものが好ましい。
【０１１０】
前記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、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などがある。更に、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−（Ｎ−ビニルベンジルアミノエチル）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、ｐ−メチルフェニルトリメトキシシランなどが挙げられる。
【０１１１】
又、脂肪酸としては、ウンデシル酸、ラウリン酸、トリデカン酸、ミリスチン酸、パルミチン酸、ペンタデカン酸、ステアリン酸、ヘプタデカン酸、アラキン酸、モンタン酸、オレイン酸、リノール酸、アラキドン酸などの長鎖脂肪酸が挙げられ、その金属塩としては亜鉛、鉄、マグネシウム、アルミニウム、カルシウム、ナトリウム、リチウムなどの金属との塩が挙げられる。
【０１１２】
上記のような微粒子を本発明の電子写真感光体の中間層に分散、含有させることにより、電子写真特性、特に繰り返し使用時の電位の湿度依存性、更に黒ポチ、環境メモリ等の改善効果を増大させることができる。
【０１１３】
次に、本発明の電子写真感光体の電荷発生層及び電荷発生物質について説明する。
【０１１４】
まず、本発明の電子写真感光体に用いられる電荷発生物質が、示差熱分析において７０℃〜１５０℃の間に吸熱ピークを有しないことについて説明する。
【０１１５】
電荷発生物質が示差熱分析において７０〜１５０℃の間に吸熱ピークを示すのは、広い意味の結晶水（ゼオライト型結晶水を含む：水分子の脱吸着が可能な結晶水を有する）を有する電荷発生顔料が７０〜１５０℃の間で結晶水を放出するために生じる吸熱するピークであり、前記７０〜１５０℃で吸熱ピークを有しない電荷発生物質は、顔料内部に結晶水を持たない電荷発生物質を意味している。
【０１１６】
電荷発生層の電荷発生物質として、上記のような示差熱分析において７０〜１５０℃の間に吸熱ピークを有しない電荷発生物質を前記本発明の中間層と併用することにより、高温高湿から低温低湿条件に作業環境が変化した場合に発生しやすい前記した環境メモリの発生を抑制し、又、反転現像での黒ポチの発生を抑制し、帯電電位や感度等の電子写真特性を安定に保つことが出来る。
【０１１７】
示差熱分析は１回の測定につき１０〜５０ｍｇの試料量にて測定し、窒素雰囲気下、昇温速度１０（℃／ｍｉｎ）で測定した。測定試料の状態としては、予め測定対象となる電荷発生物質を５０℃、３時間、乾燥した電荷発生物質粉末を用いた。又、この７０〜１５０℃の間の示差熱分析の吸熱ピークとは、図２に示すように熱示差曲線上の明瞭なピークのことを指しており、吸熱ピーク温度はピークの極大となる点に相当する温度を示す。
【０１１８】
本発明の７０〜１５０℃の間に吸熱ピークを有しない電荷発生物質の例としては、フタロシアニン顔料、アゾ顔料、ペリレン顔料、アズレニウム顔料等で結晶水を有しない電荷発生顔料が挙げられるが、チタニルフタロシアニンが好ましい。本発明に好ましく用いられる具体例としては、Ｃｕ−Ｋα特性Ｘ線によるＸ線回折スペクトルのブラッグ角（２θ±０．２°）で、最大回折ピークが２６．２°、且つ９．３°に強い回折ピークを有するチタニルフタロシアニン顔料（図３）である。なお、図３のＣｕ−Ｋα特性Ｘ線によるＸ線回折スペクトルの図を更に細かく観察すると、ブラッグ角（２θ±０．２°）で、最大回折ピークが２６．２°、且つ９．３°、１０．６°、１３．２°、１５．１°及び２０．８°に強い回折ピークを有している。或いはＣｕ−Ｋα特性Ｘ線によるＸ線回折スペクトルのブラッグ角（２θ±０．２°）で、７．５°及び２８．６°に強い回折ピークを有するチタニルフタロシアニン顔料（図４）である。なお、図４のＣｕ−Ｋα特性Ｘ線によるＸ線回折スペクトルの図を更に細かく観察すると、ブラッグ角（２θ±０．２°）で、７．５°、１０．３°、１２．３°、１６．３°、１８．４°、２２．６°、２４．５°、２５．３°及び２８．６°に強い回折ピークを有している。これらの電荷発生物質は前者のチタニルフタロシアニン顔料が、特開昭６２−６７０９８号、同６２−２５６８６６号等に記載されており、後者のチタニルフタロシアニン顔料が、特開昭６１−２３９２４８号、同６１−２１７０７５号等に記載されている。
【０１１９】
電荷発生層には前記した示差熱分析において、７０〜１５０℃の間に吸熱ピークを有しない電荷発生物質（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。
【０１２０】
又、電荷発生物質（ＣＧＭ）としては本発明の７０〜１５０℃の間に吸熱ピークを有しない電荷発生物質の他、必要により、７０〜１５０℃の間に吸熱ピークを有する電荷発生物質を使用してもよいが、この場合でも５０質量％以上は吸熱ピークを有しない電荷発生物質を用いることが好ましい。
【０１２１】
前記したチタニルフタロシアニン顔料の化学構造式は、代表的に下記構造が、良く知られている。
【０１２２】
【化８】

【０１２３】
（式中、Ｘはハロゲン原子を表し、ｎは０〜１の数を示す）。前記Ｘが塩素原子の場合ｎは０〜０．５が好ましく、０〜０．１がより好ましい。
【０１２４】
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。
【０１２５】
次に、本発明の電子写真感光体の電荷輸送層及び電荷輸送物質について説明する。
【０１２６】
本発明の電子写真感光体の電荷輸送層は、トリフェニルアミン構造を有する電荷輸送物質を含有する。
【０１２７】
本発明の電子写真感光体の電荷輸送層に用いられるトリフェニルアミン構造を有する化合物として好ましいのは、前記一般式（Ｔ）で表される化合物である。
【０１２８】
【化９】

【０１２９】
一般式（Ｔ）中、Ｒ_１及びＲ_１′は、同一でも異なっていてもよく、それぞれ水素原子、ハロゲン原子、置換、未置換のアルキル基又は置換、未置換のアルコキシ基を表し、Ｒ_２、Ｒ_２′Ｒ_３及びＲ_３′は、同一でも異なっていてもよく、それぞれ水素原子、ハロゲン原子、置換、未置換のアルキル基、置換、未置換のアリル基、置換、未置換のアルケニル基、置換、未置換のアルコキシ基又は置換アミノ基を表し、ｍ及びｎはそれぞれ０、１又は２を表す。
【０１３０】
本発明に係るトリフェニルアミン構造を有する化合物の具体例を以下に示すが、これらに限定されるものではない。
【０１３１】
【化１０】

【０１３２】
【化１１】

【０１３３】
【化１２】

【０１３４】
【化１３】

【０１３５】
【化１４】

【０１３６】
【化１５】

【０１３７】
【化１６】

【０１３８】
【化１７】

【０１３９】
【化１８】

【０１４０】
【化１９】

【０１４１】
【化２０】

【０１４２】
【化２１】

【０１４３】
【化２２】

【０１４４】
【化２３】

【０１４５】
【化２４】

【０１４６】
【化２５】

【０１４７】
【化２６】

【０１４８】
【化２７】

【０１４９】
【化２８】

【０１５０】
【化２９】

【０１５１】
【化３０】

【０１５２】
【化３１】

【０１５３】
【化３２】

【０１５４】
【化３３】

【０１５５】
【化３４】

【０１５６】
本発明に係るトリフェニルアミン構造を有する電荷輸送性化合物は、負帯電機能分離型感光体、単層感光体或いは逆層構成等の感光体に用いることができ、特に感光体の種類に限定されるものではない。
【０１５７】
本発明の電子写真感光体に用いられる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。
【０１５８】
電荷輸送層（ＣＴＬ）に用いられる樹脂としては、例えばポリスチレン、アクリル樹脂、メタクリル樹脂、塩化ビニル樹脂、酢酸ビニル樹脂、ポリビニルブチラール樹脂、エポキシ樹脂、ポリウレタン樹脂、フェノール樹脂、ポリエステル樹脂、アルキッド樹脂、ポリカーボネート樹脂、シリコーン樹脂、メラミン樹脂並びに、これらの樹脂の繰り返し単位構造のうちの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。
【０１５９】
これらＣＴＬのバインダーとして最も好ましいものはポリカーボネート樹脂である。また、ポリカーボネート樹脂の粘度平均分子量は５０００〜５００００が好ましい。この範囲の年度平均分子量のポリカーボネート樹脂はＣＴＭの分散性、電子写真特性を良好にすることにおいて、最も好ましい。バインダー樹脂と電荷輸送物質との割合は、バインダー樹脂１００質量部に対し１０〜２００質量部が好ましい。又、電荷輸送層の膜厚は１０〜４０μｍが好ましい。
【０１６０】
本発明の電子写真感光体としては本発明の目的からは有機電子写真感光体（有機感光体とも云う）が好ましい。有機感光体とは電子写真感光体の構成に必要不可欠な電荷発生機能及び電荷輸送機能の少なくとも一方の機能を有機化合物に持たせて構成された電子写真感光体を意味し、公知の有機電荷発生物質又は有機電荷輸送物質から構成された感光体、電荷発生機能と電荷輸送機能を高分子錯体で構成した感光体等公知の有機電子写真感光体を全て含有する。
【０１６１】
有機感光体の層構成は、導電性支持体上に、中間層、電荷発生層、電荷輸送層を有するが、必要によりその上に表面層を塗設した構成でもよい。又、表面層は保護層の機能と電荷輸送の機能を有しているので電荷輸送層を代わりに用いてもよい。
【０１６２】
以下に本発明の電子写真感光体の具体的な構成について記載する。
導電性支持体
本発明の電子写真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。
【０１６３】
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。
【０１６４】
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。
【０１６５】
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。
【０１６６】
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。
【０１６７】
電荷発生層及び電荷輸送層
本発明の電子写真感光体の電荷発生層及び電荷輸送層の構成は前記中間層上に電荷発生機能と電荷輸送機能を１つの層に持たせた単層構造の構成でも良いが、より好ましくは前記した電荷発生層（ＣＧＬ）と前記した電荷輸送層（ＣＴＬ）とを有する構成とするのがよい。機能を分離した構成を取ることにより繰り返し使用に伴う残留電位増加を小さく制御でき、その他の電子写真特性を目的に合わせて制御しやすい。負帯電用の感光体では中間層の上に電荷発生層（ＣＧＬ）、その上に電荷輸送層（ＣＴＬ）の構成を取ることが好ましい。正帯電用の感光体では前記層構成の順が負帯電用感光体の場合の逆となる。本発明の最も好ましい層構成は前記機能分離構造を有する負帯電感光体構成である。
【０１６８】
表面層
感光体の表面層（保護層）として、シロキサンポリカーボネートや架橋タイプのシロキサン系樹脂をバインダーとした層を設けてもよい。
【０１６９】
上記では本発明の最も好ましい感光体の層構成を例示したが、本発明では上記以外の感光体層構成でも良い。
【０１７０】
電荷発生層、電荷輸送層、中間層、表面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。
【０１７１】
又、これらの各層の塗布溶液は塗布工程に入る前に、塗布溶液中の異物や凝集物を除去するために、金属フィルター、メンブランフィルター等で濾過することが好ましい。例えば、日本ポール社製のプリーツタイプ（ＨＤＣ）、デプスタイプ（プロファイル）、セミデプスタイプ（プロファイルスター）等を塗布液の特性に応じて選択し、濾過をすることが好ましい。
【０１７２】
次に有機電子写真感光体を製造するための塗布加工方法としては、浸漬塗布、スプレー塗布、円形量規制型塗布等の塗布加工法が用いられる。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。
【０１７３】
次に、本発明の電子写真感光体を用いた画像形成装置について説明する。
図５は本発明の画像形成方法の１例としての画像形成装置の断面図である。
【０１７４】
図５において５０は像担持体であり本発明に係る電子写真感光体である感光体ドラムである。感光体ドラム５０は接地されて時計方向に駆動回転される。５２はスコロトロンの帯電器（帯電手段）で、感光体ドラム５０周面に対し一様な帯電をコロナ放電によって与えられる。この帯電器５２による帯電に先だって、前画像形成での感光体の履歴をなくすために発光ダイオード等を用いた帯電前露光部５１による露光を行って感光体周面の除電をしてもよい。
【０１７５】
感光体ドラム５０への一様帯電の後、像露光手段としての像露光器５３により画像信号に基づいた像露光が行われる。この図の像露光器５３は図示しないレーザダイオードを露光光源とする。回転するポリゴンミラー５３１、ｆθレンズ等を経て反射ミラー５３２により光路を曲げられた光により感光体ドラム上の走査がなされ、静電潜像が形成される。
【０１７６】
ここで本発明の反転現像プロセスとは帯電器５２により、感光体表面を一様に帯電し、像露光が行われた領域、即ち感光体の露光部電位（露光部領域）を現像工程（手段）により、顕像化する画像形成方法である。一方未露光部電位は現像スリーブ５４１に印加される現像バイアス電位により現像されない。
【０１７７】
その静電潜像は次いで現像手段としての現像器５４で現像される。感光体ドラム５０周縁にはトナーとキャリアとから成る現像剤を内蔵した現像器５４が設けられていて、マグネットを内蔵し現像剤を保持して回転する現像スリーブ５４１によって現像が行われる。現像器５４内部は現像剤攪拌搬送部材５４４、５４３、搬送量規制部材５４２等から構成されており、現像剤は攪拌、搬送されて現像スリーブに供給されるが、その供給量は該搬送量規制部材５４２により制御される。該現像剤の搬送量は適用される有機電子写真感光体の線速及び現像剤比重によっても異なるが、一般的には２０〜２００ｍｇ／ｃｍ^２の範囲である。
【０１７８】
現像剤は、例えば前述のフェライトをコアとしてそのまわりに絶縁性樹脂をコーティングしたキャリアと、前述のスチレンアクリル系樹脂を主材料としてカーボンブラック等の着色剤と荷電制御剤と低分子量ポリオレフィンからなる着色粒子に、シリカ、酸化チタン等を外添したトナーとからなるもので、現像剤は搬送量規制部材によって層厚を規制されて現像域へと搬送され、現像が行われる。この時通常は感光体ドラム５０と現像スリーブ５４１の間に直流バイアス、必要に応じて交流バイアス電圧をかけて現像が行われる。また、現像剤は感光体に対して接触あるいは非接触の状態で現像される。感光体ドラム５０の電位測定は電位センサー５４７を図５のように現像位置上部に設けて行う。
【０１７９】
記録紙Ｐは画像形成後、転写のタイミングの整った時点で給紙ローラー５７の回転作動により転写域へと給紙される。
【０１８０】
転写域においては転写のタイミングに同期して感光体ドラム５０の周面に転写電極（転写手段：転写器）５８が作動し、給紙された記録紙Ｐにトナーと反対極性の帯電を与えてトナーを転写する。
【０１８１】
次いで記録紙Ｐは分離電極（分離器）５９によって除電がなされ、感光体ドラム５０の周面により分離して定着装置６０に搬送され、熱ローラー６０１と圧着ローラー６０２の加熱、加圧によってトナーを溶着したのち排紙ローラー６１を介して装置外部に排出される。なお前記の転写電極５８及び分離電極５９は記録紙Ｐの通過後、一次作動を中止し、次なるトナー像の形成に備える。図５では転写電極５８にコロトロンの転写帯電極を用いている。転写電極の設定条件としては、感光体のプロセススピード（周速）等により異なり一概に規定することはできないが、例えば、転写電流としては＋１００〜＋４００μＡ、転写電圧としては＋５００〜＋２０００Ｖを設定値とすることができる。
【０１８２】
一方記録紙Ｐを分離した後の感光体ドラム５０は、クリーニング器（クリーニング手段）６２のブレード６２１の圧接により残留トナーを除去・清掃し、再び帯電前露光部５１による除電と帯電器５２による帯電を受けて次なる画像形成のプロセスに入る。
【０１８３】
尚、７０は本発明の電子写真感光体、帯電器、転写器、分離器及びクリーニング器が一体化されている着脱可能なプロセスカートリッジである。
【０１８４】
本発明の電子写真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。
【０１８５】
【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。
【０１８６】
実施例１
以下のようにして各実施例、比較例の中間層分散液を作製した。
【０１８７】
感光体１の作製

ポリアミドＮ−１をイソプロピルアルコールで加温溶解後、定格濾過精度０．２μｍのフィルターにて濾過後、酸化チタンを混合、該混合液を分散部分の構造がセラミックで表面加工されたサンドミル分散機で、分散時間１０時間、バッチ式にて分散し中間層分散液を作製した。
【０１８８】
上記中間層分散液を同じ混合溶媒を用いて２倍に希釈し、一夜静置後に濾過（フィルター；日本ポール社製プロファイルスター絶対濾過精度：１．５μｍ、圧力；１００ｋＰａ以下）し、洗浄済みの円筒状アルミニウム基体上に浸漬塗布法で塗布し、乾燥膜厚２μｍの中間層を形成した。
【０１８９】
乾燥後の中間層の体積抵抗は前記測定条件で２×１０^１０Ω・ｃｍであった。
〈電荷発生層（ＣＧＬ）〉
電荷発生物質；チタニルフタロシアニン顔料Ａ　　　　　　　　　　２０ｇ
ポリビニルブチラール（＃６０００−Ｃ、電気化学工業社製）　　　１０ｇ
酢酸ｔ−ブチル　　　　　　　　　　　　　　　　　　　　　　　７００ｇ
４−メトキシ−４−メチル−２−ペンタノン　　　　　　　　　　３００ｇ
上記組成物を混合し、サンドミルを用いて分散し、電荷発生層塗布液を調製した。この塗布液を浸漬塗布法で塗布し、前記中間層の上に乾燥膜厚０．３μｍの電荷発生層を形成した。
【０１９０】
〈電荷輸送層（ＣＴＬ）〉
電荷輸送物質（化合物（Ｔ_１−３））　　　　　　　　　　　　　　　７５ｇ
ポリカーボネート樹脂（ユーピロンＺ３００：三菱ガス化学社製）１００ｇ
テトラヒドロフラン　　　　　　　　　　　　　　　　　　　　　６００ｇ
トルエン　　　　　　　　　　　　　　　　　　　　　　　　　　１５０ｇ
上記組成物を混合し、溶解して電荷輸送層塗布液を調製した。この塗布液を前記電荷発生層の上に浸漬塗布法で塗布し、乾燥膜厚２４μｍの電荷輸送層を形成し感光体１を作製した。
【０１９１】
感光体２〜１５の作製
中間層分散液のポリアミド樹脂、微粒子及びその表面処理と粒径、及び溶剤及び電荷発生層の電荷発生物質、電荷輸送層の電荷輸送物質を表１、表２のように変更した他は、感光体１の作製と同様にして、それぞれ感光体２〜１５を作製した（但し、感光体の中間層乾燥膜厚は０．６μｍに形成した）。
【０１９２】
これら感光体２〜１５の中間層の体積抵抗は、前記測定条件下で０．５×１０^１０〜６×１０^１０Ω・ｃｍであった。
【０１９３】
尚、表１、表２中、１次処理、２次処理は、微粒子である酸化チタンに行う表面処理であり、最初に行う処理を１次処理、後に行う処理を２次処理としている。１次処理欄に記載のものは酸化チタンの１次処理時に用いた物質であり、２次処理欄に記載のものは２次処理時に用いた物質を示す。
【０１９４】
電荷発生物質の示差熱分析における７０〜１５０℃の吸熱ピークの検出
表１、表２中の電荷発生物質の示差熱分析における７０〜１５０℃の吸熱ピークの検出は前記した条件で、室温（２４℃）から１７０℃まで昇温し測定した。
【０１９５】
測定機：島津製作所「島津熱流速示差走査熱量計ＤＳＣ−５０」を用いて測定した。
【０１９６】
又、表１、表２中の中間層に用いる樹脂の融解熱、吸水率の測定は以下のようにして行った。
【０１９７】
融解熱の測定条件
測定機：島津製作所「島津熱流速示差走査熱量計ＤＳＣ−５０」を用いて測定した。
【０１９８】
測定条件：測定試料を上記測定機に設定し、室温（２４℃）から測定開始、２００℃迄５℃／分で昇温し、次いで室温まで５℃／分で冷却する。これを２回連続で行い、２回めの昇温時の融解による吸熱ピーク面積より融解熱を算出する。
【０１９９】
吸水率の測定条件
測定対象の試料を７０〜８０℃で３〜４時間で十分に乾燥させ、その質量を精密に秤量する。次に、２０℃に維持したイオン交換水に試料を投入し、一定時間経過後に引き上げ試料表面の水を清潔な布で拭き取り、質量を測定する。以上の操作を質量増が飽和するまで繰り返し、その結果得られた試料の増加質量（増加分）を初期の質量で徐した値を吸水率とした。
【０２００】
【表１】

【０２０１】
【表２】

【０２０２】
表中、電荷発生物質の欄のＡは図３のＸ線回折スペクトルのチタニルフタロシアニン顔料、Ｂは図４のＸ線回折スペクトルのチタニルフタロシアニン顔料、Ｙは図１のＸ線回折スペクトルのチタニルフタロシアニン顔料を示す。Ａ、Ｂは前記示差熱分析において７０〜１５０℃の間に吸熱ピークを有していないが、Ｙは７０〜１５０℃の間に吸熱ピークを有していた。
【０２０３】
化合物（２）は下記の化合物である。
【０２０４】
【化３５】

【０２０５】
又、炭素数が７以上の単位構造の比率とは、繰り返し単位構造のアミド結合間の炭素数が７以上の繰り返し単位構造の比率（モル％）を示す。又、Ｎ−１２はメトキシメチル化ナイロン６（アシド結合間の炭素数は５であり、メトキシメチル化度は２５％）、Ｎ−１３は下記構造のポリアミドを示す。
【０２０６】
【化３６】

【０２０７】
上記Ｎ−１３構造の（）内の％は繰り返し単位構造のアミド結合間の炭素数が７以上の繰り返し単位構造の比率（モル％）を示す。
【０２０８】
評価（画像評価）
Ｋｏｎｉｃａ７０５０（コニカ社製レーザデジタル複写機：感光体と帯電器、現像器、クリーニング装置及び除電器とが一体となったカートリッジを備えている）に感光体１〜１２を装着し、反転現像で評価した。帯電条件及びクリーニング条件等の画像形成条件は下記のように設定した。
【０２０９】
帯電条件
帯電器；初期帯電電位を−６５０Ｖ
現像条件
ＤＣバイアス　；約−５００Ｖ
現像剤層規制　；磁性Ｈ−Ｃｕｔ方式
現像スリーブ径；４０ｍｍ
転写極；コロナ帯電方式、転写ダミー電流値：４５μＡ
クリーニング条件
弾性体ゴムブレード；自由長：９ｍｍ、厚さ：２ｍｍ、硬度：７０°、反発弾性：３５、感光体当接圧（線圧）：１５ｇ／ｃｍ
評価項目
上記のように感光体１〜１２をＫｏｎｉｃａ７０５０に装着し、３０℃、８０％ＲＨ環境下（ＨＨ）において、Ａ４紙１万枚のコピーを行い、コピー画像の環境メモリ、カブリ、黒ポチ等について以下の評価基準にて目視で画像評価を行った。
【０２１０】
コピーは画素率が７％の文字画像、ハーフトーン画像、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での複写を行い評価した。
【０２１１】
各評価項目の判定基準は、下記に示す通りである。
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。多数枚のコピーで残留電位が増加すると、画像濃度が低下する。）
◎：黒ベタ画像が１．３以上
○：黒ベタ画像が１．３未満〜１．２
△：黒ベタ画像が１．２未満〜１．０
×：黒ベタ画像が１．０未満
カブリ
マクベス反射濃度計「ＲＤ−９１８」を用いて、印字されていないコピー用紙（白紙）の濃度を２０カ所、絶対画像濃度で測定し、その平均値を白紙濃度とする。次に、コピー画像の白地部分を同様に２０カ所、絶対画像濃度で測定し、その平均濃度から前記白紙濃度を引いた値をカブリ濃度として評価した。帯電電位の低下が大きくなるとカブリが発生する。
【０２１２】
◎：ベタ白画像濃度が０．００３未満（非常に良好）
○：ベタ白画像濃度が０．００３以上０．００５未満（良好）
△：ベタ白画像濃度が０．００５以上０．０１未満（実用上問題なし）
×：０．０１以上（実用上問題あり）
環境メモリ：上記Ｋｏｎｉｃａ７０５０複写機をＨＨ下に２４ｈｒ放置後、低湿低温下（ＬＬ：２０ＲＨ％、１０℃）に置き、３０分後、コピーした。オリジナル画像で０．４の濃度のハーフトーン画像を０．４の濃度にコピー、コピー画像の濃度差（ΔＨＤ＝最大濃度−最小濃度）で判定
◎：ΔＨＤが０．０５以下（非常に良好）
○：ΔＨＤが０．０５以下（良好）
△：ΔＨＤが０．０５より大で０．１未満（実用上問題なし）
×：ΔＨＤが０．１以上（実用上問題あり）
黒ポチ
黒ポチについては、周期性が感光体の周期と一致し、目視できる黒ポチが、Ａ４サイズ当たり何個あるかで判定した。
【０２１３】
◎：０．４ｍｍ以上の黒ポチ頻度：全ての複写画像が１個／Ａ４以下（非常に良好）
○：０．４ｍｍ以上の黒ポチ頻度：２個／Ａ４以上、３個／Ａ４以下が１枚以上発生（良好）
△：０．４ｍｍ以上の黒ポチ頻度：４個／Ａ４以上、１０個／Ａ４以下が１枚以上発生（実用上問題なし）
×：０．４ｍｍ以上の黒ポチ頻度：１１個／Ａ４以上が１枚以上発生（実用上問題有り）
評価結果を表３に示す。
【０２１４】
【表３】

【０２１５】
表３より本発明の感光体は、上記画像濃度、カブリ、環境メモリ、黒ポチの評価が良好な特性を示していることが分かった。
【０２１６】
【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電子写真感光体を用いることにより、カブリ、黒ポチ特性が良好であり、更に温湿度条件の環境変化に対して発生しやすい画像不良の発生が防止され、良好な電子写真画像を形成することができる。又該電子写真感光体を用いた画像形成方法、画像形成装置及びプロセスカートリッジを提供することが出来る。
【図面の簡単な説明】
【図１】ブラッグ角（２θ±０．２°）で、最大回折ピークが、２７．３°であるチタニルフタロシアニン顔料のＸ線回折スペクトルの図である。
【図２】７０〜１５０℃の間の示差熱分析の吸熱ピークを示す図である。
【図３】ブラッグ角（２θ±０．２°）で、最大回折ピークが２６．３°、且つ９．３°、１０．６°、１３．２°、１５．１°及び２０．８°に強い回折ピークを有するチタニルフタロシアニン顔料のＸ線回折スペクトルの図である。
【図４】ブラッグ角（２θ±０．２°）で、７．５°、１０．３°、１２．３°、１６．３°、１８．４°、２２．６°、２４．５°、２５．３°及び２８．７°に強い回折ピークを有するチタニルフタロシアニン顔料のＸ線回折スペクトルの図である。
【図５】本発明の画像形成方法の１例としての画像形成装置の断面図である。
【符号の説明】
５０　感光体ドラム（又は感光体）
５１　帯電前露光部
５２　帯電器
５３　像露光器
５４　現像器
５４１　現像スリーブ
５４３，５４４　現像剤攪拌搬送部材
５４７　電位センサー
５７　給紙ローラー
５８　転写電極
５９　分離電極（分離器）
６０　定着装置
６１　排紙ローラー
６２　クリーニング器
７０　プロセスカートリッジ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member used in the field of a copying machine or a printer, and an image forming apparatus, an image forming method, and a process cartridge using the electrophotographic photosensitive member.
[0002]
[Prior art]
Electrophotographic photoreceptors (hereinafter, also simply referred to as photoreceptors) mainly include inorganic photoreceptors such as Se, arsenic, arsenic / Se alloy, CdS, ZnO, etc., and organic photoreceptors which are excellent in advantages such as pollution and ease of production. Moving on, organic photoreceptors using various materials have been developed.
[0003]
In recent years, function-separated type photoreceptors in which charge generation and charge transport functions are assigned to different materials have become the mainstream, and among them, a stacked organic photoreceptor in which a charge generation layer and a charge transport layer are stacked is widely used. Have been.
[0004]
Turning to the electrophotographic process, the latent image forming method is roughly classified into analog image forming using a halogen lamp as a light source and digital image forming using an LED or a laser as a light source. Recently, digital latent image forming systems are rapidly becoming the mainstream as printers for hard copy of personal computers, and also in ordinary copying machines, because of their ease of image processing and development in multifunction machines.
[0005]
In digital image formation, a laser, particularly a semiconductor laser or LED, is used as a light source when writing image information converted into a digital electric signal as an electrostatic latent image on a photoconductor.
[0006]
The oscillation wavelength of the laser light or the LED light is near-infrared light of 780 nm or 660 nm or long-wavelength light close thereto. For organic photoreceptors used for digital image formation, the first required property is high sensitivity to these long-wavelength lights. Studies have been made on whether or not to have such characteristics. Among them, phthalocyanine pigments are relatively easy to synthesize and, in many cases, exhibit high sensitivity to long-wavelength light, and organic photoconductors using phthalocyanine pigments have been widely studied and put to practical use. .
[0007]
Among them, a titanyl phthalocyanine pigment having a maximum peak at a Bragg angle 2θ of 27.2 ± 0.2 ° in a powder X-ray diffraction spectrum (an X-ray diffraction spectrum is shown in FIG. 1. Hereinafter, simply referred to as a Y-type titanyl phthalocyanine pigment). Is known as a highly sensitive material and has been reported at academic conferences (Oda et al., Journal of Electrophotographic Society, 29 (3), 250 (1990), etc.). Furthermore, Fujimaki discovered that the photon efficiency of this Y-type titanyl phthalocyanine pigment was reduced by dehydration treatment in a dried inert gas. However, the decrease in the photon efficiency increases the quantum efficiency again when water is reabsorbed in a room temperature and normal humidity environment, so that the Y-type titanyl phthalocyanine pigment has a crystal structure containing water, and this water molecule has It promotes the dissociation of excitonic holes and electrons generated by light, which is presumed to be one of the causes of high photon efficiency. (Y. Fujimaki: IS &T's 7th International Congress on Advance in Non-impact Printing Technologies, Paper Summers, 269 (1991))
When such a material is used as a carrier-generating substance, charging characteristics and sensitivity characteristics change due to environmental changes, particularly humidity changes, and an environmental memory is likely to be generated.
[0008]
As a result of studying the above problems, the present inventors have found that the effect of the intermediate layer adjacent to the charge generation layer is great as a measure against the humidity fluctuation.
[0009]
For example, a method of forming an intermediate layer by dispersing titanium oxide particles or the like in a polyamide resin is widely known. However, mainly used as a polyamide resin in this case, mainly a copolymerized polyamide resin or a methoxymethylated polyamide resin composed of a chemical structure having a small number of carbon chains between amide bonds such as 6-nylon, has a high water absorption, The intermediate layer using such a polyamide tends to have a high environmental dependency. As a result, the residual potential increases due to repeated use, and the charging characteristics under high temperature and high humidity are easily changed. When the environment is changed from a low temperature environment to a low temperature and low humidity environment, a band-like image defect is generated) and black spots are easily generated.
[0010]
Copolyamide resins composed of structural units having a large number of carbon chains between amide bonds, such as 12-nylon resins, are effective materials for producing a photoreceptor having low environmental dependency due to low water absorption. is expected. However, such polyamides are insoluble in ordinary organic solvents and are not suitable for producing photoconductors. As described in JP-A-5-72787 and JP-A-6-186767, there is an example in which the solubility is improved by methoxymethylation. However, methoxymethylation significantly increases the water absorption, so that black is used. It is difficult to make the poty and environmental memory low enough.
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to suppress the occurrence of environmental memory by improving the change in humidity of charging characteristics and sensitivity characteristics when using a titanyl phthalocyanine pigment or the like. Another object of the present invention is to provide an electrophotographic photosensitive member free from occurrence of image defects such as black spots, and to provide an image forming method, an image forming apparatus, and a process cartridge using the electrophotographic photosensitive member.
[0012]
[Means for Solving the Problems]
The present invention has been studied to improve the above-mentioned drawbacks of the electrophotographic photoreceptor, and as a result of examining the characteristics of the charge generation material and the binder resin used for the intermediate layer, mainly the humidity dependency, it was found that the charge generation material By using an organic pigment that does not contain water of crystallization and using a resin having low crystallinity and low water absorption for the binder resin of the intermediate layer, the charging characteristics of the photoreceptor and the humidity resistance dependency of the sensitivity characteristics are improved. It has been found that no fogging occurs and the occurrence of image defects such as black spots and environmental memory can be prevented, and particularly excellent effects have been confirmed by using a charge transport material having a specific triphenylamine structure. Was completed. That is, the present invention is achieved by having the following configuration.
[0013]
(1) On a conductive support, an intermediate layer containing a resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less, and an endotherm between 70 ° C and 150 ° C in differential thermal analysis. An electrophotographic photoreceptor comprising: a charge generating layer containing a charge generating substance having no peak; and a charge transporting layer containing a charge transporting substance having a triphenylamine structure.
[0014]
(2) The electrophotographic photosensitive member according to (1), wherein the resin is an alcohol-soluble polyamide.
[0015]
(3) The electrophotographic photoreceptor according to (1) or (2), wherein the intermediate layer contains fine particles having a number average primary particle size of 10 to 400 nm.
[0016]
(4) The electrophotographic photosensitive member according to (3), wherein the fine particles are titanium oxide particles.
[0017]
(5) The electrophotographic photosensitive member according to (3) or (4), wherein the fine particles have been subjected to a surface treatment.
[0018]
(6) The fine particles have been subjected to a plurality of surface treatments, and the final surface treatment is a surface treatment with a reactive silicon compound, (3) to (5). Electrophotographic photoreceptor.
[0019]
(7) The electron according to (6), wherein at least one of the plurality of surface treatments is a surface treatment with at least one compound selected from alumina, silica, and zirconia. Photoreceptor.
[0020]
(8) The electrophotographic photoreceptor according to any one of (1) to (7), wherein the charge generating substance is titanyl phthalocyanine.
[0021]
(9) The titanyl phthalocyanine has a maximum diffraction peak of 26.2 ° and a strong diffraction peak of 9.3 ° at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. The electrophotographic photosensitive member according to (8), having:
[0022]
(10) The titanyl phthalocyanine has strong diffraction peaks at 7.5 ° and 28.6 ° in a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. (8) The electrophotographic photosensitive member according to (8).
[0023]
(11) The titanyl phthalocyanine has a maximum diffraction peak of 26.2 °, 9.3 °, 10.6 at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. The electrophotographic photoreceptor according to (8), having strong diffraction peaks at °, 13.2 °, 15.1 ° and 20.8 °.
[0024]
(12) The titanyl phthalocyanine is 7.5 °, 10.3 °, 12.3 °, 16.3 at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. The electrophotographic photoreceptor according to (8), having a strong diffraction peak at °, 18.4 °, 22.6 °, 24.5 °, 25.3 ° and 28.6 °.
[0025]
(13) The electrophotographic photoreceptor according to any one of (1) to (12), wherein the charge transport layer contains a polycarbonate resin having a viscosity average molecular weight of 5,000 to 50,000.
[0026]
(14) An image forming apparatus comprising the electrophotographic photosensitive member according to any one of (1) to (13).
[0027]
(15) An image forming method, wherein an electrophotographic image is formed using the image forming apparatus according to (14).
[0028]
(16) The electrophotographic photosensitive member according to any one of (1) to (13), charging means for uniformly charging the electrophotographic photosensitive member, and an electrostatic latent image on the charged electrophotographic photosensitive member Image forming means for forming an image, developing means for developing an electrostatic latent image on the electrophotographic photosensitive member, and transfer means for transferring a toner image developed on the electrophotographic photosensitive member onto a transfer material At least one of a charge removing means for removing charge on the electrophotographic photosensitive member after transfer and a cleaning means for removing toner remaining on the electrophotographic photosensitive member after transfer is integrally supported; A process cartridge detachably mountable to a forming apparatus main body.
[0029]
Hereinafter, the present invention will be described in detail.
The present inventors have developed an intermediate layer containing a resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less on a conductive support. A charge generating layer containing a charge generating substance having no endothermic peak between the charge generating layer and a charge transporting layer containing a charge transporting substance having a triphenylamine structure; It has been found that it is possible to obtain a good electrophotographic image in which the generation of environmental memory is suppressed by improving the humidity change of the sensitivity characteristic and the occurrence of image defects such as black spots is suppressed.
[0030]
First, the intermediate layer of the electrophotographic photosensitive member of the present invention will be described.
The resin used for the intermediate layer of the electrophotographic photosensitive member of the present invention has a heat of solution of 0 to 40 J / g and a water absorption of 5% by mass or less.
[0031]
By setting the heat of fusion of the resin in the intermediate layer to 0 to 40 J / g, the decrease in the solvent solubility of the resin is suppressed, the generation of fine aggregates of the binder resin in the intermediate layer is prevented, and the microscopic physical properties are uniform. The generation of black spots and an increase in the residual potential due to insufficient properties are suppressed, and the uniformity of the dispersion of the charge generating material is not sufficient, so that the generation of environmental memory can be suppressed. The heat of fusion is more preferably 0 to 30 J / g, most preferably 0 to 20 J / g. Thereby, the effect of the present invention can be further obtained.
[0032]
On the other hand, by controlling the water absorption of the resin in the intermediate layer to 5% by mass or less, the increase in the water content in the intermediate layer is suppressed, black spots and environmental memory are prevented from occurring, and the residual potential is increased and fog is generated. , Etc., can be suppressed. The water absorption is more preferably 3% by mass or less, whereby the effect of the present invention can be further obtained.
[0033]
The heat of fusion of the resin is measured by DSC (Differential Scanning Calorimetry). However, as long as the same measured value as the measured value of the DSC is obtained, the DSC measurement method is not limited. The heat of fusion is determined from the endothermic peak area at the time of DSC temperature rise.
[0034]
On the other hand, the water absorption of the resin is determined by a change in mass by an immersion method in water or the Karl Fischer method.
[0035]
As the resin of the intermediate layer of the present invention, an alcohol-soluble polyamide resin is preferable. As the binder resin for the intermediate layer of the electrophotographic photosensitive member, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolyamide resin or a methoxymethylated polyamide resin composed of a chemical structure having a small number of carbon chains between amide bonds such as 6-nylon described above are known. Resin has a high water absorption, and the intermediate layer using such a polyamide tends to have a high environmental dependency. As a result, for example, the charging characteristics under high temperature and high humidity are easily changed, and the environmental memory (high temperature and high temperature) When the environment is changed from a humid environment to a low-temperature and low-humidity environment, a band-like image defect is generated) and black spots are easily generated.
[0036]
The alcohol-soluble polyamide resin of the present invention is improved in the above-mentioned disadvantages, and has a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less. And an excellent electrophotographic image can be obtained even if the external environment changes or the electrophotographic photosensitive member is used continuously for a long time.
[0037]
The alcohol-soluble polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less will be described below.
[0038]
As the alcohol-soluble polyamide resin, a polyamide resin containing a repeating unit structure having 7 to 30 carbon atoms between amide bonds in an amount of 40 to 100 mol% of the entire repeating unit structure is preferable.
[0039]
Here, a repeating unit structure having 7 to 30 carbon atoms between amide bonds will be described. The repeating unit structure means an amide bond unit forming a polyamide resin. This is because a polyamide resin formed by condensation of a compound having both an amino group and a carboxylic acid group (type A) and a polyamide resin formed by condensation of a diamino compound and a dicarboxylic acid compound (type B) ).
[0040]
That is, the type A repeating unit structure is represented by the general formula (2), and the number of carbon atoms contained in X is the number of carbon atoms of the amide bond unit in the repeating unit structure. On the other hand, the type B repeating unit structure is represented by the general formula (3), and both the number of carbon atoms contained in Y and the number of carbon atoms contained in Z are the number of carbon atoms of the amide bond unit in the repeating unit structure.
[0041]
Embedded image

[0042]
In the general formula (2), R ₁ represents a hydrogen atom, a substituted or unsubstituted alkyl group, X represents a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, It shows a mixed structure, and 1 shows a natural number.
[0043]
Embedded image

[0044]
In the general formula (3), R ₂ and R ₃ are each a hydrogen atom, a substituted or unsubstituted alkyl group, and Y and Z are each a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, and a divalent group. And m and n are natural numbers.
[0045]
As described above, the repeating unit structure having 7 to 30 carbon atoms has a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, and a chemical structure having a mixed structure thereof. Among them, a chemical structure having a group containing a divalent cycloalkane is preferable.
[0046]
The polyamide resin of the present invention has 7 to 30 carbon atoms between amide bonds of the repeating unit structure, preferably 9 to 25, and more preferably 11 to 20. The proportion of the repeating unit structure having 7 to 30 carbon atoms between amide bonds in the total repeating unit structure is 40 to 100 mol%, preferably 60 to 100 mol%, and more preferably 80 to 100 mol%.
[0047]
When the number of carbon atoms is smaller than 7, the polyamide resin has a large hygroscopic property, electrophotographic properties, particularly a large potential dependence on humidity when repeatedly used, and black spots, environmental memory and the like are easily generated. When it is larger than 30, the polyamide resin is poorly dissolved in the coating solvent, and is not suitable for forming a coating film of the intermediate layer.
[0048]
When the proportion of the repeating unit structure having 7 to 30 carbon atoms between amide bonds occupies less than 40 mol% of all the repeating unit structures, the above effect is reduced.
[0049]
Preferred polyamide resins of the present invention include polyamides having a repeating unit structure represented by the following general formula (1).
[0050]
Embedded image

[0051]
In the general formula (1), Y ₁ represents a group containing a divalent alkyl-substituted cycloalkane, Z ₁ represents a methylene group, m represents 1 to 3, and n represents 3 to 20.
[0052]
In the general formula (1), the group containing a divalent alkyl-substituted cycloalkane for Y ₁ preferably has the following chemical structure. That is, the polyamide resin of the present invention in which Y ₁ has the following chemical structure has remarkable effects on environmental memory and black spots.
[0053]
Embedded image

[0054]
In the above chemical structure, A represents a single bond, an alkylene group having 1 to 4 carbon atoms, R ₄ represents a substituent, an alkyl group, and p represents a natural number of 1 to 5. However, a plurality of R ₄ may be the same or different.
[0055]
Specific examples of the polyamide resin of the present invention include the following examples.
[0056]
Embedded image

[0057]
Embedded image

[0058]
Embedded image

[0059]
The percentages in parentheses in the above specific examples indicate the ratio (mol%) of the repeating unit structure having 7 or more carbon atoms between the amide bonds of the repeating unit structure.
[0060]
Among the above specific examples, N-1 to N-4 polyamide resins having a repeating unit structure of the general formula (1) are particularly preferable.
[0061]
The molecular weight of the polyamide resin of the present invention is preferably 5,000 to 80,000 in terms of number average molecular weight, more preferably 10,000 to 60,000. If the number average molecular weight is 5,000 or less, the uniformity of the thickness of the intermediate layer is deteriorated, and the effect of the present invention is hardly exerted. On the other hand, when it is larger than 80,000, the solvent solubility of the resin is apt to decrease, an agglomerated resin is easily generated in the intermediate layer, and image defects such as black spots are easily generated.
[0062]
A part of the polyamide resin of the present invention is already commercially available. For example, the polyamide resin is sold under a trade name of Vestamelt X1010 or X4685 manufactured by Daicel Degussa Co., Ltd., and is produced by a general polyamide synthesis method. The following is an example of a synthesis example.
[0063]
In a polymerization vessel equipped with a synthetic stirrer, nitrogen, a nitrogen inlet tube, a thermometer, a dehydration tube, and the like for a synthetic polyamide resin (N-1), 215 parts by mass of lauryl lactam, 3-aminomethyl-3,5,5-trimethylcyclohexylamine 112 parts by mass, 153 parts by mass of 1,12-dodecanecarboxylic acid and 2 parts by mass of water were mixed and reacted under heating and pressure for 9 hours while distilling water. The polymerization product ^was taken out was determined the copolymer composition by C 13 -NMR, it was consistent with the composition of the N-1. The melt flow index (MFI) of the synthesized copolymer was 5 g / 10 min under the condition of (230 ° C./2.16 kg).
[0064]
As a solvent for dissolving the polyamide resin of the present invention to prepare a coating solution, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol and sec-butanol are used. Preferably, it is excellent in solubility of polyamide and applicability of the prepared coating solution. These solvents are used in an amount of 30 to 100% by mass, preferably 40 to 100% by mass, and more preferably 50 to 100% by mass in the total solvent. Examples of the co-solvent which can obtain a preferable effect when used in combination with the above-mentioned solvent include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, tetrahydrofuran and the like.
[0065]
In the intermediate layer of the present invention, it is preferable that the polyamide resin contains fine particles having a primary particle diameter of 10 to 400 nm.
[0066]
The number average primary particle diameter is a value obtained by magnifying a fine particle by a factor of 10,000 by transmission electron microscope observation, randomly observing 100 particles as primary particles, and analyzing the image as an average diameter in the Feret direction.
[0067]
When such fine particles are contained in the intermediate layer, moire caused by laser light, which is one of image defects, can be reduced, and free carriers (electrons and holes entering from a conductive support or the like) in the intermediate layer can be blocked. It is known that such fine particles are contained in the intermediate layer, the fine particles tend to increase the humidity, and often have a high temperature and humidity environment dependency. In the present invention, even if an intermediate layer containing such fine particles is formed by using a resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less as the binder resin for the intermediate layer, An intermediate layer having stable characteristics against external temperature and humidity changes can be obtained. As a result, the electrophotographic characteristics of the photoconductor are stable, and the photoconductor has stable characteristics against external temperature and humidity changes. Can be obtained.
[0068]
Examples of such fine particles include oxides such as cerium oxide, chromium oxide, aluminum oxide, magnesium oxide, silicon oxide, tin oxide, zirconium oxide, iron oxide, and titanium oxide; and sulfuric acid such as calcium sulfate, barium sulfate, and aluminum sulfate. Salts; silicates such as calcium silicate and magnesium silicate; nitrides such as boron nitride and titanium nitride; carbides such as silicon carbide, titanium carbide, boron carbide, tungsten carbide and zirconium carbide; zirconium boride, titanium boride and the like And the like, and as the fine particles of the present invention, the following N-type semiconductive fine particles are preferable.
[0069]
The N-type semiconductive particles are fine particles having a property of using a conductive carrier as an electron. That is, since the conductive layer has a property of using electrons as an electron, the intermediate layer containing the N-type semiconductor particles in an insulating binder can efficiently block hole injection from the substrate, It has the property of having a low blocking property against electrons from.
[0070]
Specific examples of the N-type semiconductive particles include fine particles such as titanium oxide (TiO ₂ ), zinc oxide (ZnO), and tin oxide (SnO ₂ ). In the present invention, titanium oxide is particularly preferably used. Can be
[0071]
The average particle diameter of the fine particles used in the intermediate layer of the electrophotographic photoreceptor of the present invention is preferably in the range of 10 nm to 400 nm in number average primary particle diameter, and more preferably 15 nm to 200 nm. When the thickness is 10 nm or more, the effect of preventing the generation of moire by the intermediate layer can be increased. On the other hand, by setting the thickness to 400 nm or less, sedimentation of the N-type semiconductor particles in the coating liquid for the intermediate layer is suppressed, and as a result, the uniform dispersibility of the N-type semiconductor particles in the intermediate layer is improved. Can also suppress the increase. The coating liquid for the intermediate layer using the N-type semiconductor particles having the number average primary particle diameter in the above range has good dispersion stability, and the intermediate layer formed from such a coating liquid has a function of preventing black spots from occurring. Good environmental characteristics and cracking resistance.
[0072]
The number average primary particle diameter of the fine particles is, for example, in the case of titanium oxide, magnified 10000 times by transmission electron microscopy, randomly observe 100 particles as primary particles, and analyze the number average diameter of Feret diameter by image analysis. Measured as
[0073]
The shape of the fine particles used in the present invention includes dendritic, needle-like and granular shapes, and N-type semiconductive particles having such a shape are, for example, titanium oxide particles, as the crystal type, anatase type, There are a rutile type, an amorphous type, and the like, and any crystal type may be used, or a mixture of two or more types may be used. Among them, the rutile type and granular type are the best.
[0074]
The fine particles used in the present invention are preferably surface-treated. This makes it possible to obtain a good photoreceptor having good dispersibility of fine particles in the intermediate layer and free from image defects such as black spots.
[0075]
Further, it is preferable that the fine particles used in the present invention are subjected to a surface treatment a plurality of times, and of the plurality of the surface treatments, the last surface treatment is performed by a surface treatment using a reactive organic silicon compound. As a result, it is possible to obtain a good photoreceptor in which the dispersibility of the fine particles in the intermediate layer is even better and image defects such as black spots are not generated.
[0076]
In the fine particles used in the present invention, at least one surface treatment may be at least one kind of surface treatment selected from alumina, silica, and zirconia, and finally, a surface treatment using a reactive organosilicon compound may be performed. More preferred.
[0077]
It is also preferable that the surface treatment is performed a plurality of times using alumina and silica, and then the surface treatment is performed using a reactive organic silicon compound.
[0078]
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 fine particles. Is also included. Further, the surface treatment of the reactive organosilicon compound means to use the reactive organosilicon compound in the treatment solution.
[0079]
As described above, by performing the surface treatment of the fine particles such as the titanium oxide particles, the surface of the fine particles is uniformly coated (treated), and when the surface-treated fine particles are used for the intermediate layer, the titanium oxide in the intermediate layer is removed. A good photoreceptor having good dispersibility of N-type semiconductive particles such as particles and not causing image defects such as black spots can be obtained.
[0080]
The above-described treatment of alumina and silica may be performed simultaneously, but it is particularly preferable to perform the silica treatment first, and then perform the alumina treatment. In the case where alumina and silica are respectively treated, the amount of alumina and silica to be treated is preferably larger than that of alumina.
[0081]
The surface treatment of the fine particles such as titanium oxide with a metal oxide such as alumina, silica, and zirconia can be performed by a wet method. For example, N-type semiconductive particles that have been subjected to silica or alumina surface treatment can be prepared as follows.
[0082]
When titanium oxide particles are used as the N-type semiconductor particles, titanium oxide particles (number average primary particle diameter: 50 nm) are dispersed in water at a concentration of 50 to 350 g / L to form an aqueous slurry, and the aqueous slurry is added thereto. An acid salt or a water-soluble aluminum compound is added. After that, neutralization is performed by adding an alkali or an acid to deposit silica or alumina on the surface of the titanium oxide particles. Subsequently, filtration, washing and drying are performed to obtain a target surface-treated titanium oxide. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid or hydrochloric acid. On the other hand, when aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide.
[0083]
The amount of the metal oxide used in the surface treatment is 0.1 to 50 parts by mass with respect to 100 parts by mass of N-type semiconductive particles such as titanium oxide particles in the amount charged during the surface treatment. More preferably, 1 to 10 parts by mass of a metal oxide is used. In the case of using the above alumina and silica, for example, in the case of titanium oxide particles, it is preferable to use 1 to 10 parts by mass with respect to 100 parts by mass of titanium oxide particles, and it is preferable that the amount of silica is larger than that of alumina. .
[0084]
The surface treatment with the reactive organic silicon compound, which is performed after the surface treatment with the metal oxide, is preferably performed by the following wet method.
[0085]
That is, the titanium oxide treated with the metal oxide is added to a liquid in which the reactive organic silicon compound is dissolved or suspended in an organic solvent or water, and the liquid is subjected to media dispersion using ceramic beads. Is preferred. Next, the dispersion liquid after the dispersion of the medium is filtered and then dried under reduced pressure while performing a heat treatment to obtain titanium oxide particles whose surface is coated with an organosilicon compound. The reactive organic silicon compound may be added to a suspension in which titanium oxide is dispersed in an organic solvent or water.
[0086]
In the present invention, the fact that the surface of the titanium oxide particles is coated with the reactive organosilicon compound may be determined by photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Auger), secondary ion mass spectroscopy (SIMS), or diffuse reflection. It can be confirmed by combining surface analysis techniques such as FI-IR.
[0087]
The amount of the reactive organosilicon compound used for the surface treatment is, with respect to 100 parts by mass of the titanium oxide treated with the metal oxide in the charged amount at the time of the surface treatment, the reactive organosilicon compound is 0.1 to 0.1 parts by mass. 50 parts by mass, more preferably 1 to 10 parts by mass. If the surface treatment amount is less than the above range, the surface treatment effect is not sufficiently provided, and the dispersibility and the like of the titanium oxide particles in the intermediate layer deteriorate. Further, when the value exceeds the above range, the electric performance is deteriorated, and as a result, the residual potential increases and the charging potential decreases.
[0088]
Examples of the reactive organosilicon compound used in the present invention include a compound represented by the following general formula (4). If the compound has a condensation reaction with a reactive group such as a hydroxyl group on the surface of titanium oxide, the following compound may be used. It is not limited to.
[0089]
General formula (4)
(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 (4), 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 and β- (3,4-epoxycyclohexyl) ethyl; γ-acryloxypropyl; γ-methacryloxypropyl A (meth) acryloyl group, a hydroxyl group such as γ-hydroxypropyl and 2,3-dihydroxypropyloxypropyl, a vinyl group such as vinyl and propenyl, a mercapto group such as γ-mercaptopropyl, a γ-aminopropyl, An amino-containing group such as N-β (aminoethyl) -γ-aminopropyl, γ-chloropropyl, , 1,1-tri 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.
[0090]
The organosilicon compound represented by the general formula (4) may be used alone or in combination of two or more.
[0091]
When n is 2 or more in the specific compound of the organosilicon compound represented by the general formula (4), 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 (4) are used, R and X may be the same or different between the respective compounds.
[0092]
Examples of the compound where n is 0 include the following compounds.
Tetrachlorosilane, diethoxydichlorosilane, tetramethoxysilane, phenoxytrichlorosilane, tetraacetoxysilane, tetraethoxysilane, tetraallyloxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrakis (2-methoxyethoxy) silane, tetrabutoxysilane , Tetraphenoxysilane, tetrakis (2-ethylbutoxy) silane, tetrakis (2-ethylhexyloxy) silane and the like.
[0093]
Examples of the compound in which n is 1 include the following compounds.
That is, trichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, ethyltrichlorosilane, allyltrichlorosilane, n-propyltrichlorosilane, n-butyltrichlorosilane, chloromethyltriethoxysilane, methyltrimethoxysilane, mercaptomethyltrimethoxysilane, Trimethoxyvinylsilane, ethyltrimethoxysilane, 3,3,4,4,5,5,6,6,6-nonafluorohexyltrichlorosilane, phenyltrichlorosilane, 3,3,3-trifluoropropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, triethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, ben Rutrichlorosilane, methyltriacetoxysilane, chloromethyltriethoxysilane, ethyltriacetoxysilane, phenyltrimethoxysilane, 3-allylthiopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-bromopropyltriethoxysilane , 3-allylaminopropyltrimethoxysilane, propyltriethoxysilane, hexyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, bis (ethylmethylketoxime) methoxymethylsilane, pentyltri Ethoxysilane, octyltriethoxysilane, dodecyltriethoxysilane and the like can be mentioned.
[0094]
Examples of the compound in which n is 2 include the following compounds.
Dimethyldichlorosilane, dimethoxymethylsilane, dimethoxydimethylsilane, methyl-3,3,3-trifluoropropyldichlorosilane, diethoxysilane, diethoxymethylsilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3 -Chloropropyldimethoxymethylsilane, chloromethyldiethoxysilane, diethoxydimethylsilane, dimethoxy-3-mercaptopropylmethylsilane, 3,3,4,4,5,5,6,6,6-nonafluorohexylmethyldi Chlorosilane, methylphenyldichlorosilane, diacetoxymethylvinylsilane, diethoxymethylvinylsilane, 3-methacryloxypropylmethyldichlorosilane, 3-aminopropyldiethoxymethylsilane, 3- (2-aminoethylaminopropyl Pill) dimethoxymethylsilane, t-butylphenyldichlorosilane, 3-methacryloxypropyldimethoxymethylsilane, 3- (3-cyanopropylthiopropyl) dimethoxymethylsilane, 3- (2-acetoxyethylthiopropyl) dimethoxymethylsilane, Dimethoxymethyl-2-piperidinoethylsilane, dibutoxydimethylsilane, 3-dimethylaminopropyldiethoxymethylsilane, diethoxymethylphenylsilane, diethoxy-3-glycidoxypropylmethylsilane, 3- (3-acetoxypropyl Thio) propyldimethoxymethylsilane, dimethoxymethyl-3-piperidinopropylsilane, diethoxymethyloctadecylsilane and the like.
[0095]
Examples of the compound in which n is 3 include the following compounds.
Examples thereof include trimethylchlorosilane, methoxytrimethylsilane, ethoxytrimethylsilane, methoxydimethyl-3,3,3-trifluoropropylsilane, 3-chloropropylmethoxydimethylsilane, and methoxy-3-mercaptopropylmethylmethylsilane.
[0096]
As the organosilicon compound represented by the general formula (4), an organosilicon compound represented by the following general formula (5) is preferably used.
[0097]
General formula (5)
R-Si-X ₃
In the formula, R represents an alkyl group, an aryl group, and X represents a methoxy group, an ethoxy group, or a halogen group.
[0098]
In the organosilicon compound represented by the general formula (5), more preferably, an organosilicon compound in which R is an alkyl group having 4 to 8 carbon atoms, and specific preferred compound examples include trimethoxy n-butylsilane , Trimethoxy i-butylsilane, trimethoxyhexylsilane, and trimethoxyoctylsilane.
[0099]
A preferred reactive organosilicon compound used for the final 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.
[0100]
In particular, when methyl hydrogen polysiloxane is used for the final surface treatment, a good effect can be obtained.
[0101]
Another one of the surface treatments of the titanium oxide of the present invention is titanium oxide particles that have been surface-treated with an organosilicon compound having a fluorine atom. The surface treatment with the organosilicon compound having a fluorine atom is preferably performed by the above-mentioned wet method.
[0102]
That is, the organosilicon compound having a fluorine atom is dissolved or suspended in an organic solvent or water, untreated titanium oxide is added thereto, such a solution is dispersed in a medium, filtered, and heated. After the application, it is dried and the surface of titanium oxide is coated with an organosilicon compound having a fluorine atom. The organic silicon compound having a fluorine atom may be added to a suspension in which titanium oxide is dispersed in an organic solvent or water.
[0103]
The fact that the surface of the titanium oxide is coated with an organosilicon compound having a fluorine atom can be determined by photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Auger), secondary ion mass spectroscopy (SIMS), or diffuse reflection FI. -It can be confirmed compositely using a surface analyzer such as IR.
[0104]
Examples of the organosilicon compound having a fluorine atom used in the present invention include 3,3,4,4,5,5,6,6,6-nonafluorohexyltrichlorosilane, 3,3,3-trifluoropropyltrimethoxy Silane, methyl-3,3,3-trifluoropropyldichlorosilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3,3,4,4,5,5,6,6,6-nonafluoro Hexylmethyldichlorosilane and the like.
[0105]
The amount of the N-type semiconductive particles dispersed in the polyamide resin is, for example, in the case of surface-treated titanium oxide, 10 to 10,000 parts by mass, preferably 50 to 1,000 parts by mass with respect to 100 parts by mass of the binder resin. 000 parts by mass. By using the surface-treated titanium oxide in this range, the dispersibility of the titanium oxide can be kept good, and a good intermediate layer free of black spots can be formed.
[0106]
Further, the intermediate layer of the present invention is substantially an insulating layer. Here, the insulating layer has a volume resistance of 1 × 10 ⁸ to 10 ¹⁵ Ω · cm. The volume resistance of the intermediate layer of the present invention is preferably 1 × 10 ⁹ to 10 ¹⁴ Ω · cm, and more preferably 2 × 10 ⁹ to 1 × 10 ¹³ Ω · cm. Volume resistance can be measured as follows.
[0107]

If the volume resistance is less than 1 × 10 ⁸ , the charge blocking property of the intermediate layer is reduced, the occurrence of black spots is increased, and the potential retention of the electrophotographic photoreceptor is deteriorated, so that good image quality cannot be obtained. On the other hand, when it is larger than 10 ¹⁵ Ω · cm, the residual potential tends to increase in repeated image formation, and good image quality cannot be obtained.
[0108]
As the dispersion solvent used for forming the intermediate layer of the electrophotographic photoreceptor of the present invention, those similar to the above-mentioned polyamide resin solvents are appropriately used.
[0109]
In addition to the above fine particles, metal oxide fine particles are also preferably used. Examples of the metal oxide fine particles include oxides such as cerium oxide, chromium oxide, aluminum oxide, magnesium oxide, silicon oxide, and tin oxide. One of these oxides, or two as needed, may be used. It is preferable to use the above metal oxides. Further, it is preferable that these metal oxides are hydrophobized by a hydrophobizing agent such as a titanium coupling agent, a silane coupling agent, a high molecular fatty acid or a metal salt thereof.
[0110]
Examples of the titanium coupling agent include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, and bis (dioctyl pyrophosphate) oxyacetate titanate. Further, as a silane coupling agent, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltri Examples include methoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, and the like.
[0111]
In addition, as fatty acids, long chain fatty acids such as undecylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, pentadecanoic acid, stearic acid, heptadecanoic acid, arachinic acid, montanic acid, oleic acid, linoleic acid, and arachidonic acid. Examples of the metal salt include salts with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.
[0112]
By dispersing and including the fine particles as described above in the intermediate layer of the electrophotographic photoreceptor of the present invention, the electrophotographic properties, especially the humidity dependency of the potential upon repeated use, the black spots, and the effect of improving environmental memory and the like can be improved. Can be increased.
[0113]
Next, the charge generation layer and the charge generation material of the electrophotographic photoreceptor of the present invention will be described.
[0114]
First, the fact that the charge generating substance used in the electrophotographic photoreceptor of the present invention does not have an endothermic peak between 70 ° C and 150 ° C in differential thermal analysis will be described.
[0115]
The reason why the charge generating substance shows an endothermic peak between 70 ° C. and 150 ° C. in the differential thermal analysis is that it has a wide meaning of crystallization water (including zeolite-type crystallization water: having crystallization water capable of desorbing water molecules). An endothermic peak generated when the charge generating pigment emits water of crystallization between 70 and 150 ° C., and the charge generating material having no endothermic peak at 70 to 150 ° C. is a charge having no water of crystallization inside the pigment. Means generated material.
[0116]
As a charge generation material of the charge generation layer, a charge generation material having no endothermic peak at 70 to 150 ° C. in the above-described differential thermal analysis is used in combination with the intermediate layer of the present invention, so that the temperature is reduced from high temperature to high humidity to low temperature. Suppress the occurrence of the above-mentioned environmental memory, which is likely to occur when the working environment changes to low humidity conditions, suppress the occurrence of black spots in reversal development, and stably maintain electrophotographic characteristics such as charging potential and sensitivity. I can do it.
[0117]
The differential thermal analysis was performed with a sample amount of 10 to 50 mg per one measurement, and the measurement was performed under a nitrogen atmosphere at a heating rate of 10 (° C./min). As a state of the measurement sample, a charge generation material powder which was previously dried at 50 ° C. for 3 hours. The endothermic peak in the differential thermal analysis between 70 and 150 ° C. refers to a clear peak on the thermal differential curve as shown in FIG. 2, and the endothermic peak temperature is a point at which the peak becomes a maximum. Shows the temperature corresponding to.
[0118]
Examples of the charge generating substance having no endothermic peak at 70 to 150 ° C. of the present invention include phthalocyanine pigments, azo pigments, perylene pigments, azulhenium pigments and other charge generating pigments having no crystallization water. Phthalocyanines are preferred. As a specific example preferably used in the present invention, the maximum diffraction peak is 26.2 ° and 9.3 ° at the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by Cu-Kα characteristic X-ray. It is a titanyl phthalocyanine pigment having a strong diffraction peak (FIG. 3). In addition, when the X-ray diffraction spectrum of the Cu-Kα characteristic X-ray in FIG. 3 is observed in more detail, the maximum diffraction peak is 26.2 ° and 9.3 ° at the Bragg angle (2θ ± 0.2 °). , 10.6 °, 13.2 °, 15.1 ° and 20.8 °. Alternatively, it is a titanyl phthalocyanine pigment having strong diffraction peaks at 7.5 ° and 28.6 ° at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum by Cu-Kα characteristic X-ray (FIG. 4). In addition, when the figure of the X-ray diffraction spectrum by the Cu-Kα characteristic X-ray in FIG. 4 is observed in more detail, 7.5 °, 10.3 °, 12.3 ° at Bragg angles (2θ ± 0.2 °). , 16.3 °, 18.4 °, 22.6 °, 24.5 °, 25.3 ° and 28.6 °. For these charge generating substances, the former titanyl phthalocyanine pigments are described in JP-A Nos. 62-67098 and 62-256866, and the like, and the latter titanyl phthalocyanine pigments are described in JP-A Nos. 61-239248 and 61-239248. No.-217075.
[0119]
The charge generation layer contains a charge generation material (CGM) having no endothermic peak between 70 and 150 ° C. in the differential thermal analysis described above. As other substances, a binder resin and other additives may be contained as necessary.
[0120]
In addition, as the charge generating material (CGM), in addition to the charge generating material having no endothermic peak between 70 and 150 ° C. of the present invention, a charge generating material having an endothermic peak between 70 and 150 ° C. is used as necessary. However, even in this case, it is preferable to use a charge generating substance having no endothermic peak at 50% by mass or more.
[0121]
As the chemical structural formula of the titanyl phthalocyanine pigment described above, the following structure is typically well known.
[0122]
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[0123]
(Wherein, X represents a halogen atom, and n represents a number from 0 to 1). When X is a chlorine atom, n is preferably from 0 to 0.5, more preferably from 0 to 0.1.
[0124]
In the case where a binder is used as a dispersion medium of CGM in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is a formal resin, a butyral resin, a silicone resin, a silicone-modified butyral resin, a phenoxy resin, and the like. No. The ratio between the binder resin and the charge generating substance is preferably from 20 to 600 parts by mass per 100 parts by mass of the binder resin. By using these resins, an increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably from 0.1 μm to 2 μm.
[0125]
Next, the charge transport layer and the charge transport material of the electrophotographic photoreceptor of the present invention will be described.
[0126]
The charge transport layer of the electrophotographic photoreceptor of the present invention contains a charge transport material having a triphenylamine structure.
[0127]
Preferred as the compound having a triphenylamine structure used in the charge transport layer of the electrophotographic photoreceptor of the present invention is the compound represented by the formula (T).
[0128]
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[0129]
In the general formula (T), R ₁ and R ₁ ′ may be the same or different and each represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group, and R ₂ , R ₂ ′ R ₃ and R ₃ ′ may be the same or different and each represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted allyl group, a substituted or unsubstituted alkenyl group. , A substituted or unsubstituted alkoxy group or a substituted amino group, and m and n each represent 0, 1 or 2.
[0130]
Specific examples of the compound having a triphenylamine structure according to the present invention are shown below, but the invention is not limited thereto.
[0131]
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[0132]
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[0133]
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[0134]
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[0135]
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[0136]
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[0137]
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[0138]
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[0139]
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[0140]
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[0141]
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[0142]
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[0143]
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[0144]
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[0145]
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[0146]
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[0147]
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[0148]
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[0149]
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[0150]
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[0151]
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[0152]
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[0153]
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[0154]
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[0155]
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[0156]
The charge-transporting compound having a triphenylamine structure according to the present invention can be used for a negatively charged function-separated type photoreceptor, a single-layer photoreceptor or a photoreceptor having a reverse layer structure, and is particularly limited to the type of the photoreceptor. Not something.
[0157]
The charge transport layer used in the electrophotographic photoreceptor of the present invention contains a charge transport material (CTM) and a binder resin for dispersing the CTM to form a film. As other substances, additives such as antioxidants may be contained as necessary.
[0158]
Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating unit structures of these resins. In addition to these insulating resins, polymer organic semiconductors such as poly-N-vinyl carbazole may be used.
[0159]
The most preferred binder for these CTLs is a polycarbonate resin. Further, the viscosity average molecular weight of the polycarbonate resin is preferably 5,000 to 50,000. A polycarbonate resin having an annual average molecular weight in this range is most preferable in improving the dispersibility and electrophotographic properties of CTM. The ratio between the binder resin and the charge transporting material is preferably from 10 to 200 parts by mass per 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably from 10 to 40 μm.
[0160]
As the electrophotographic photosensitive member of the present invention, an organic electrophotographic photosensitive member (also referred to as an organic photosensitive member) is preferable for the purpose of 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 a known organic charge generation. It includes all known organic electrophotographic photoreceptors such as a photoreceptor composed of a substance or an organic charge transporting substance, and a photoreceptor having a charge generation function and a charge transporting function composed of a polymer complex.
[0161]
The layer structure of the organic photoreceptor includes an intermediate layer, a charge generation layer, and a charge transport layer on a conductive support, and may have a surface layer provided thereon if necessary. Further, since the surface layer has the function of the protective layer and the function of charge transport, the charge transport layer may be used instead.
[0162]
Hereinafter, a specific configuration of the electrophotographic photoreceptor of the present invention will be described.
Conductive Support As the conductive support used in the electrophotographic photosensitive member of the present invention, a sheet-like or cylindrical conductive support is used.
[0163]
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.
[0164]
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 preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.
[0165]
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.
[0166]
Intermediate layer In the present invention, the above-mentioned intermediate layer having a barrier function is provided between the conductive support and the photosensitive layer.
[0167]
Charge Generation Layer and Charge Transport Layer The charge generation layer and charge transport layer of the electrophotographic photoreceptor of the present invention have a single-layer structure in which the intermediate layer has a charge generation function and a charge transport function in one layer. However, it is more preferable to adopt a configuration including the above-described charge generation layer (CGL) and the above-described charge transport layer (CTL). By adopting a configuration in which functions are separated, an increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoreceptor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the case of a positively charged photoreceptor, the order of the layer configuration is opposite to that in the case of a negatively charged photoreceptor. The most preferred layer constitution of the present invention is a negatively charged photoreceptor constitution having the function separation structure.
[0168]
Surface Layer As the surface layer (protective layer) of the photoreceptor, a layer using siloxane polycarbonate or a crosslinkable siloxane-based resin as a binder may be provided.
[0169]
Although the most preferred layer configuration of the photoreceptor of the present invention has been described above, other layer configurations of the photoreceptor may be used in the present invention.
[0170]
As a solvent or a dispersion medium used for forming a layer such as a charge generation layer, a charge transport layer, an intermediate layer, and a surface layer, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethyl Formamide, 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, Ruserosorubu, 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.
[0171]
Further, it is preferable that the coating solution for each of these layers is filtered through a metal filter, a membrane filter or the like in order to remove foreign substances and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleated type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pall Co., Ltd. in accordance with the characteristics of the coating solution, and then perform filtration.
[0172]
Next, as an application processing method for manufacturing an organic electrophotographic photosensitive member, an application processing method such as dip coating, spray coating, and circular amount control type coating is used. The circular amount control type coating is described in detail in, for example, JP-A-58-189061.
[0173]
Next, an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described.
FIG. 5 is a sectional view of an image forming apparatus as an example of the image forming method of the present invention.
[0174]
In FIG. 5, reference numeral 50 denotes an image bearing member, which is a photosensitive drum which is an electrophotographic photosensitive member according to the present invention. The photosensitive drum 50 is grounded and driven to rotate clockwise. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the peripheral surface of the photosensitive drum 50 by corona discharge. Prior to the charging by the charger 52, in order to eliminate the history of the photoreceptor in the previous image formation, exposure by the pre-charging exposure unit 51 using a light emitting diode or the like may be performed to remove the charge on the peripheral surface of the photoreceptor.
[0175]
After the photosensitive drum 50 is uniformly charged, image exposure based on an image signal is performed by an image exposure device 53 as an image exposure unit. The image exposure device 53 in this figure uses a laser diode (not shown) as an exposure light source. The light on the photosensitive drum is scanned by the light whose optical path is bent by the reflection mirror 532 via the rotating polygon mirror 531 and the fθ lens and the like, and an electrostatic latent image is formed.
[0176]
Here, the reversal development process of the present invention is to uniformly charge the surface of the photoreceptor by the charger 52, and to develop the image-exposed region, that is, the exposed portion potential (exposed portion region) of the photoreceptor in the developing step (means). ) Is an image forming method for visualizing the image. On the other hand, the unexposed portion potential is not developed by the developing bias potential applied to the developing sleeve 541.
[0177]
The electrostatic latent image is then developed by a developing device 54 as a developing unit. A developing device 54 containing a developer including a toner and a carrier is provided on the peripheral edge of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The inside of the developing device 54 is composed of developer stirring / conveying members 544 and 543, a conveyance amount regulating member 542, and the like. The developer is agitated and conveyed and supplied to the developing sleeve. Controlled by member 542. The transport amount of the developer varies depending on the linear velocity of the applied organic electrophotographic photosensitive member and the specific gravity of the developer, but is generally in the range of ^{20 to} 200 mg / cm ² .
[0178]
The developer is, for example, a carrier formed by coating the above-described ferrite core with an insulating resin around the core, a coloring agent such as carbon black, a charge control agent, and a low molecular weight polyolefin using the above-described styrene acrylic resin as a main material. The toner is composed of a toner in which silica, titanium oxide, or the like is externally added to the particles. The developer is transported to the developing area with the layer thickness regulated by the transport amount regulating member, and is developed. At this time, development is usually performed by applying a DC bias voltage between the photosensitive drum 50 and the developing sleeve 541 and, if necessary, an AC bias voltage. Further, the developer is developed in a state of contact or non-contact with the photoconductor. The potential measurement of the photosensitive drum 50 is performed by providing a potential sensor 547 above the developing position as shown in FIG.
[0179]
After the image is formed, the recording paper P is fed to the transfer area by the rotation of the paper feed roller 57 at the time when the transfer timing is adjusted.
[0180]
In the transfer area, a transfer electrode (transfer means: transfer unit) 58 operates on the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and applies a charge of the opposite polarity to the toner to the fed recording paper P. Transfer the toner.
[0181]
Next, the recording paper P is discharged by a separation electrode (separator) 59, separated by the peripheral surface of the photosensitive drum 50, conveyed to the fixing device 60, and heated and pressed by the heat roller 601 and the pressure roller 602 to remove the toner. After welding, the sheet is discharged to the outside of the apparatus via a sheet discharge roller 61. After the transfer electrode 58 and the separation electrode 59 have passed through the recording paper P, the primary operation is stopped, and preparation is made for the formation of the next toner image. In FIG. 5, a corotron transfer band electrode is used as the transfer electrode 58. The setting conditions of the transfer electrode vary depending on the process speed (peripheral speed) of the photoreceptor and cannot be specified unconditionally. For example, the transfer current is set to +100 to +400 μA and the transfer voltage is set to +500 to +2000 V. can do.
[0182]
On the other hand, after the recording paper P is separated, the photosensitive drum 50 removes and cleans the residual toner by pressing the blade 621 of the cleaning device (cleaning means) 62, and removes electricity by the pre-charging exposure unit 51 again and charges by the charger 52 again. Then, the process of the next image formation is started.
[0183]
Reference numeral 70 denotes a detachable process cartridge in which the electrophotographic photosensitive member of the present invention, a charger, a transfer device, a separator, and a cleaning device are integrated.
[0184]
The electrophotographic photoreceptor of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, and furthermore, displays, recording, light printing, plate making, and plate making using electrophotographic technology. It can be widely applied to devices such as facsimile machines.
[0185]
【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”.
[0186]
Example 1
Intermediate layer dispersions of Examples and Comparative Examples were prepared as follows.
[0187]
Production of photoconductor 1

Polyamide N-1 was heated and dissolved in isopropyl alcohol, filtered through a filter having a rated filtration accuracy of 0.2 μm, mixed with titanium oxide, and the mixed solution was dispersed with a sand mill disperser in which the structure of the dispersed portion was surface-processed with ceramic. The mixture was dispersed in a batch system for a dispersion time of 10 hours to prepare an intermediate layer dispersion.
[0188]
The intermediate layer dispersion was diluted 2 times with the same mixed solvent, allowed to stand overnight, and filtered (filter; Absolute filtration accuracy: 1.5 μm, manufactured by Pall Corporation, pressure: 100 kPa or less), and washed. It was applied on a cylindrical aluminum substrate by a dip coating method to form an intermediate layer having a dry film thickness of 2 μm.
[0189]
The volume resistance of the dried intermediate layer was 2 × 10 ¹⁰ Ω · cm under the above measurement conditions.
<Charge generation layer (CGL)>
Charge generating substance: titanyl phthalocyanine pigment A 20 g
10 g of polyvinyl butyral (# 6000-C, manufactured by Denki Kagaku Kogyo)
700 g of t-butyl acetate
300 g of 4-methoxy-4-methyl-2-pentanone
The above composition was mixed and dispersed using a sand mill to prepare a coating solution for the charge generation layer. This coating solution was applied by dip coating to form a charge generation layer having a dry film thickness of 0.3 μm on the intermediate layer.
[0190]
<Charge transport layer (CTL)>
A charge transport material (Compound _(T 1 -3)) 75g
100 g of polycarbonate resin (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
600 g of tetrahydrofuran
150 g of toluene
The above composition was mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied on the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 24 μm, thereby producing a photoreceptor 1.
[0191]
Tables 1 and 2 show the polyamide resin, fine particles and the surface treatment and particle size of the dispersion of the intermediate layer dispersion, the solvent, the charge generating material of the charge generating layer, and the charge transporting material of the charge transporting layer. The photoconductors 2 to 15 were prepared in the same manner as the photoconductor 1 except that the thickness of the intermediate layer was 0.6 μm.
[0192]
The volume resistance of the intermediate layer of each of the photoconductors 2 to 15 was 0.5 × 10 ^{10 to} 6 × 10 ¹⁰ Ω · cm under the measurement conditions.
[0193]
In Tables 1 and 2, the primary treatment and the secondary treatment are surface treatments to be performed on titanium oxide as fine particles, and the treatment to be performed first is the primary treatment and the treatment to be performed later is the secondary treatment. The substances described in the primary treatment column are substances used in the primary treatment of titanium oxide, and those described in the secondary treatment column are substances used in the secondary treatment.
[0194]
Detection of Endothermic Peak at 70 to 150 ° C. in Differential Thermal Analysis of Charge Generating Substances Detection of the endothermic peak at 70 to 150 ° C. in differential thermal analysis of charge generating substances in Tables 1 and 2 was conducted at room temperature (24 ℃) to 170 ℃ and measured.
[0195]
Measuring machine: Measured using Shimadzu Corporation “Shimadzu heat flow rate differential scanning calorimeter DSC-50”.
[0196]
The heat of fusion and the water absorption of the resin used for the intermediate layer in Tables 1 and 2 were measured as follows.
[0197]
Measurement conditions for heat of fusion Measuring machine: Measured using Shimadzu Corporation “Shimadzu heat flow rate differential scanning calorimeter DSC-50”.
[0198]
Measurement conditions: The measurement sample is set in the above measuring instrument, measurement is started from room temperature (24 ° C.), the temperature is raised to 200 ° C. at 5 ° C./min, and then cooled to room temperature at 5 ° C./min. This is performed twice consecutively, and the heat of fusion is calculated from the endothermic peak area due to the melting at the second temperature rise.
[0199]
Conditions for measuring water absorption The sample to be measured is sufficiently dried at 70 to 80 ° C for 3 to 4 hours, and its mass is precisely weighed. Next, the sample is poured into ion-exchanged water maintained at 20 ° C., pulled up after a certain period of time, the water on the sample surface is wiped off with a clean cloth, and the mass is measured. The above operation was repeated until the mass increase was saturated, and the value obtained by reducing the increased mass (increase) of the resulting sample by the initial mass was defined as the water absorption.
[0200]
[Table 1]

[0201]
[Table 2]

[0202]
In the table, A represents a titanyl phthalocyanine pigment having an X-ray diffraction spectrum shown in FIG. 3, B represents a titanyl phthalocyanine pigment having an X-ray diffraction spectrum shown in FIG. 4, and Y represents a titanyl phthalocyanine pigment having an X-ray diffraction spectrum shown in FIG. Is shown. A and B did not have an endothermic peak between 70 and 150 ° C. in the differential thermal analysis, while Y had an endothermic peak between 70 and 150 ° C.
[0203]
Compound (2) is the following compound.
[0204]
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[0205]
Further, the ratio of the unit structure having 7 or more carbon atoms means the ratio (mol%) of the repeating unit structure having 7 or more carbon atoms between the amide bonds of the repeating unit structure. N-12 is methoxymethylated nylon 6 (the number of carbon atoms between the acid bonds is 5 and the degree of methoxymethylation is 25%), and N-13 is a polyamide having the following structure.
[0206]
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[0207]
The percentage in parentheses in the N-13 structure indicates the ratio (mol%) of the repeating unit structure having 7 or more carbon atoms between amide bonds in the repeating unit structure.
[0208]
Evaluation (image evaluation)
Konica 7050 (Konica's laser digital copying machine: equipped with a cartridge in which a photosensitive member and a charger, a developing device, a cleaning device, and a static eliminator are integrated) are mounted with photosensitive members 1 to 12, and evaluated by reversal development. did. Image forming conditions such as charging conditions and cleaning conditions were set as follows.
[0209]
Charging condition Charger: Initial charging potential is -650V
Development condition DC bias; about -500V
Developer layer regulation: Magnetic H-Cut type developing sleeve diameter: 40 mm
Transfer pole; corona charging method, transfer dummy current value: 45 μA
Cleaning conditions Elastic rubber blade; free length: 9 mm, thickness: 2 mm, hardness: 70 °, rebound resilience: 35, photosensitive member contact pressure (linear pressure): 15 g / cm
Evaluation items The photoconductors 1 to 12 were mounted on the Konica 7050 as described above, and 10,000 copies of A4 paper were copied at 30 ° C. and 80% RH environment (HH). The images were visually evaluated according to the following evaluation criteria.
[0210]
The copy was evaluated by copying an original image having a pixel rate of 7%, a halftone image, a solid white image, and a solid black image, each of which is equal to 1/4, using A4.
[0211]
The criteria for each evaluation item are as shown below.
Image density (measured using RD-918 manufactured by Macbeth Co., Ltd .; measured by relative reflection density with the reflection density of paper set to "0". The image density decreases as the residual potential increases in many copies.)
◎: Black solid image is 1.3 or more ：: Black solid image is less than 1.3 to 1.2
Δ: Black solid image is less than 1.2 to 1.0
×: The density of unprinted copy paper (white paper) was measured at 20 locations in absolute image density using a cab-Macbeth reflection densitometer “RD-918” with a solid black image of less than 1.0, and the average value was measured. Use blank paper density. Next, a white background portion of the copy image was similarly measured at 20 locations with absolute image density, and the value obtained by subtracting the blank density from the average density was evaluated as fog density. When the decrease in the charged potential is large, fog occurs.
[0212]
A: Solid white image density of less than 0.003 (very good)
：: Solid white image density of 0.003 or more and less than 0.005 (good)
C: Solid white image density of 0.005 or more and less than 0.01 (no problem in practical use)
×: 0.01 or more (there is a problem in practical use)
Environmental memory: The above Konica 7050 copying machine was left under HH for 24 hours, then placed under low humidity and low temperature (LL: 20 RH%, 10 ° C.), and after 30 minutes, copied. A halftone image having a density of 0.4 is copied to a density of 0.4 in the original image, and a determination is made based on a density difference (ΔHD = maximum density−minimum density) of the copied image ◎: ΔHD is 0.05 or less (very good)
：: ΔHD is 0.05 or less (good)
Δ: ΔHD is larger than 0.05 and smaller than 0.1 (no problem in practical use)
×: ΔHD is 0.1 or more (practical problem)
Regarding the black spots, the periodicity coincided with the period of the photoconductor, and the number of visible black spots per A4 size was determined.
[0213]
：: Black spot frequency of 0.4 mm or more: All copied images are 1 piece / A4 or less (very good)
：: Black spots of 0.4 mm or more Frequency: 2 or more A3 or more and 3 or less A4 or more occur (good)
Δ: Black spots of 0.4 mm or more Frequency: 4 pieces / A4 or more and 10 pieces / A4 or less occur 1 or more (no problem in practical use)
×: Black spots of 0.4 mm or more Frequency: 11 pieces / A4 or more occurred one or more sheets (a problem in practical use)
Table 3 shows the evaluation results.
[0214]
[Table 3]

[0215]
From Table 3, it was found that the photoreceptor of the present invention showed favorable characteristics in the evaluation of the image density, fog, environmental memory, and black spots.
[0216]
【The invention's effect】
As is clear from the examples, by using the electrophotographic photoreceptor having the configuration of the present invention, fog and black spot characteristics are good, and furthermore, image defects that are likely to occur due to environmental changes in temperature and humidity conditions. Generation is prevented, and a good electrophotographic image can be formed. Further, an image forming method, an image forming apparatus and a process cartridge using the electrophotographic photosensitive member can be provided.
[Brief description of the drawings]
FIG. 1 is an X-ray diffraction spectrum of a titanyl phthalocyanine pigment having a Bragg angle (2θ ± 0.2 °) and a maximum diffraction peak of 27.3 °.
FIG. 2 is a diagram showing an endothermic peak of differential thermal analysis between 70 and 150 ° C.
FIG. 3 shows the maximum diffraction peak at 26.3 ° and 9.3 °, 10.6 °, 13.2 °, 15.1 ° and 20.8 ° at Bragg angle (2θ ± 0.2 °). FIG. 2 is an X-ray diffraction spectrum of a titanyl phthalocyanine pigment having a strong diffraction peak.
FIG. 4 shows 7.5 °, 10.3 °, 12.3 °, 16.3 °, 18.4 °, 22.6 °, 24.5 ° in Bragg angles (2θ ± 0.2 °). FIG. 2 is an X-ray diffraction spectrum of a titanyl phthalocyanine pigment having strong diffraction peaks at, 25.3 ° and 28.7 °.
FIG. 5 is a sectional view of an image forming apparatus as an example of the image forming method of the present invention.
[Explanation of symbols]
50 Photoconductor drum (or photoconductor)
51 Exposure unit before charging 52 Charger 53 Image exposure unit 54 Developing unit 541 Developing sleeve 543, 544 Developer stirring and conveying member 547 Potential sensor 57 Feed roller 58 Transfer electrode 59 Separation electrode (separator)
Reference Signs List 60 fixing device 61 discharge roller 62 cleaning device 70 process cartridge

Claims (16)

On a conductive support,
An intermediate layer containing a resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less;
A charge generation layer containing a charge generation substance having no endothermic peak between 70 ° C. and 150 ° C. in differential thermal analysis;
A charge transport layer containing a charge transport material having a triphenylamine structure,
An electrophotographic photosensitive member comprising: The electrophotographic photosensitive member according to claim 1, wherein the resin is an alcohol-soluble polyamide. 3. The electrophotographic photoreceptor according to claim 1, wherein the intermediate layer contains fine particles having a number average primary particle size of 10 to 400 nm. The electrophotographic photosensitive member according to claim 3, wherein the fine particles are titanium oxide particles. The electrophotographic photosensitive member according to claim 3, wherein the fine particles have been subjected to a surface treatment. The electrophotographic photoreceptor according to any one of claims 3 to 5, wherein the fine particles have been subjected to a surface treatment a plurality of times, and the final surface treatment is a surface treatment with a reactive silicon compound. . The electrophotographic photoreceptor according to claim 6, wherein at least one of the plurality of surface treatments is a surface treatment with at least one compound selected from alumina, silica, and zirconia. . The electrophotographic photoreceptor according to any one of claims 1 to 7, wherein the charge generation substance is titanyl phthalocyanine. The titanyl phthalocyanine has a maximum diffraction peak of 26.2 ° and a strong diffraction peak of 9.3 ° at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. The electrophotographic photosensitive member according to claim 8, wherein: The titanyl phthalocyanine has strong diffraction peaks at 7.5 ° and 28.6 ° in a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. Item 8. The electrophotographic photosensitive member according to Item 8. The titanyl phthalocyanine has a maximum diffraction peak of 26.2 °, 9.3 °, 10.6 ° and 13 at the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by Cu-Kα characteristic X-ray. 9. The electrophotographic photoreceptor according to claim 8, having strong diffraction peaks at 0.2, 15.1 and 20.8. The titanyl phthalocyanine has a Bragg angle (2θ ± 0.2 °) of X-ray diffraction spectrum by Cu-Kα characteristic X-ray at 7.5 °, 10.3 °, 12.3 °, 16.3 °, 18 °. 9. The electrophotographic photoreceptor according to claim 8, having strong diffraction peaks at 0.4, 22.6, 24.5, 25.3, and 28.6. The electrophotographic photosensitive member according to claim 1, wherein the charge transport layer contains a polycarbonate resin having a viscosity average molecular weight of 5,000 to 50,000. An image forming apparatus comprising the electrophotographic photosensitive member according to claim 1. An image forming method, comprising: forming an electrophotographic image by using the image forming apparatus according to claim 14. An electrophotographic photosensitive member according to any one of claims 1 to 13, a charging unit for uniformly charging the electrophotographic photosensitive member, and a latent image for forming an electrostatic latent image on the charged electrophotographic photosensitive member. Forming means, developing means for visualizing the electrostatic latent image on the electrophotographic photosensitive member, transfer means for transferring the toner image visualized on the electrophotographic photosensitive member onto a transfer material, At least one of a charge removing means for removing the charge on the electrophotographic photosensitive member and a cleaning means for removing the toner remaining on the electrophotographic photosensitive member after the transfer is integrally supported, and is detachably attached to the image forming apparatus main body. A process cartridge that can be freely mounted.

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