JP2004093640A - Electrophotographic photoreceptor and process cartridge and electrophotographic apparatus having the electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having high sensitivity, little changes in the potential for repeated use and little image defects by memory characteristics or irregular coating, and to provide an electrophotographic apparatus and an electrophotographic apparatus unit using the electrophotographic photoreceptor. <P>SOLUTION: In the electrophotographic photoreceptor having a charge generating layer and a charge transfer layer on a conductive supporting body, the charge generating layer contains at least one kind of azo pigment and an oxytitanium phthalocyanine pigment showing a clear peak at 27.1° diffraction angle 2θ±0.2° in the CuKα characteristic X-ray diffraction spectrum. The layer is formed by using a coating material prepared by dispersing the above pigments in a mixture solvent of water and an organic solvent and controlling the water content to the range of ≥1 mass% and <3 mass%. The process cartridge and the electrophotographic apparatus are produced by using the above electrophotographic photoreceptor. <P>COPYRIGHT: (C)2004,JPO

Description

一般式（２）
【００１３】
【化７】

一般式（３）
【００１４】
【化８】

一般式（４）
【００１５】
【化９】

一般式（５）
【００１６】
【化１０】

一般式（１）〜（５）におけるＡ_１、Ａ_２、Ａ_３はカプラー残基を表す。
【００１７】
また、本発明に用いるオキシチタニウムフタロシアニン顔料は、ＣｕＫα特性Ｘ線回折における回折角２θ±０．２°の９．０°、１４．２°、２３．９°及び２７．１°に強いピークを有することが好ましい。
【００１８】
また、本発明のプロセスカートリッジは、前記電子写真感光体並びに、帯電手段、現像手段及びクリーニング手段からなる群より選ばれる少なくともひとつの手段を一体に支持し、電子写真装置本体に着脱自在であることを特徴とする。
【００１９】
また、本発明の電子写真装置は、前記電子写真感光体、帯電手段、像露光手段、現像手段及び転写手段を有することを特徴とする。
【００２０】
【発明の実施の形態】
以下に本発明を詳細に説明する。
【００２１】
本発明における電子写真感光体は、導電性支持体上に電荷発生層と電荷輸送層を形成した積層型感光体である。代表的な層構成を図１に示す。感光層１が電荷発生材料を含有する電荷発生層２と、電荷輸送材料を含有する電荷輸送層３の積層構造である例を示す。なお、４は導電性支持体である。
【００２２】
電荷発生層は、電荷発生材料であるオキシチタニウムフタロシアニン顔料及びアゾ顔料をバインダー樹脂及び分散溶媒に分散した電荷発生塗料を導電性支持体上に塗布して形成される。
【００２３】
オキシチタニウムフタロシアニンは、少なくともＣｕＫα特性Ｘ線回折ピークにおける回折角で２７．１°±０．２°にメインピークを持つオキシチタニウムフタロシアニンであり、下記構造式で示される。
【００２４】
【化１１】

更には、ＣｕＫα特性Ｘ線回折ピークにおける回折角（２θ±０．２）の９．０°、１４．２°、２３．９°、２７．１°に強いピークを有するオキシチタニウムフタロシアニンがより高感度で、本発明が有効に作用し、特に好ましい。
【００２５】
本発明におけるＸ線回折の測定は、ＣｕＫα線を用いて次の条件で行ったものである。
【００２６】
使用測定機：マック・サイエンス社製、全自動Ｘ線回折装置ＭＸＰ１８
Ｘ線管球：Ｃｕ
管電圧：５０ｋＶ
管電流：３００ｍＡ
スキャン方法：２θ／θスキャン
スキャン速度：４ｄｅｇ．／ｍｉｎ
サンプリング間隔：０．０２０ｄｅｇ．
スタート角度（θ）：３ｄｅｇ．
ストップ角度（θ）：４０ｄｅｇ．
ダイバージェンススリット：０．５ｄｅｇ．
スキャッタリングスリット：０．５ｄｅｇ．
レシービングスリット：０．３ｍｍ
湾曲モノクロメータ使用
【００２７】
アゾ顔料としては、搭載する電子写真装置の光源の波長に高い感度を有するものが、高感度を維持する上で好ましく、一般式（１）〜（５）で表されるものが好ましい。
【００２８】
一般式（１）
【００２９】
【化１２】

一般式（２）
【００３０】
【化１３】

一般式（３）
【００３１】
【化１４】

一般式（４）
【００３２】
【化１５】

一般式（５）
【００３３】
【化１６】

一般式（１）〜（５）におけるＡ_１、Ａ_２、Ａ_３はカプラー残基をあらわす。一般式（１）〜（３）中、Ａ_１、Ａ_２、Ａ_３で表されるカプラー残基としては、下記カプラー残基（１）〜（３）で示される基の中から選択され、１種あるいは２種以上を組み合わせてもよい。
【００３４】
カプラー残基（１）
【００３５】
【化１７】

カプラー残基（２）
【００３６】
【化１８】

カプラー残基（３）
【００３７】
【化１９】

カプラー残基（１）〜（３）中のＸは、水素原子、ハロゲン原子またはアルキル基を示す。
【００３８】
オキシチタニウムフタロシアニン顔料とアゾ顔料の比率は、９９／１〜５０／５０の範囲であることが好ましい。
【００３９】
電荷発生層を形成するにあたって、電荷発生材料を混合する場合は、各材料を上記範囲の比率で適当なバインダー樹脂と溶剤に分散するか、あるいは個々に分散した液を所定の比率になるように混合する。個々に分散する場合は、バインダー樹脂や溶剤はそれぞれ別のものでも良い。
【００４０】
バインダー樹脂としては、例えば、ポリアミド樹脂、ポリビニルブチラール樹脂、ポリエステル樹脂、アクリル樹脂、ポリカーボネート樹脂、ポリビニルアセタール樹脂、ポリスチレン樹脂、ポリアリレート樹脂、ポリビニルベンザール樹脂、ポリウレタン、エポキシ樹脂及びフェノール樹脂等が挙げられる。顔料と結着樹脂の割合は、重量比で１０：１〜１：５、好ましくは、５：１から１：４の範囲である。また、顔料の分散液における濃度は０．５〜１０質量％の範囲で分散を行うことが、分散や後処理の効率等を鑑みて好ましい。
【００４１】
分散溶媒は、有機溶剤と水の混合溶媒であればよいが、分散時の水の添加量は、顔料に対して１質量％以上、１００質量％未満とすることが好ましい。
【００４２】
有機溶剤としては親水性のものが好ましく例えば、テトラヒドロフラン、ｎ−プロピルエーテル、ｎ−ブチルエーテル及び１，４−ジオキサン等のエーテル系溶剤、エタノール、プロパノール及び２−メトキシエタノール等のアルコール系溶剤、アセトン、メチルエチルケトン及びシクロヘキサノン等のケトン系溶剤等が挙げられる。
【００４３】
分散処理は、例えば、ガラスビーズ、スチールビーズ及びアルミナボール等の分散メディアと共に、ペイントシェーカー、サンドミル、ボールミル等のミリング装置や、ホモジナイザー、超音波分散又は高圧液衝突分散装置等を用いて行うことができ、分散粒径が０．５μｍ以下、より好ましくは０．２μｍ以下になるまで顔料を分散することが、ぽちやかぶり等の画像欠陥を抑制するために好ましい。
【００４４】
分散後の塗料はこの分散液をそのまま電荷発生層用の塗布液として用いて、有機溶剤または有機溶剤と水の混合溶剤で濃度調整してもよいが、塗工時の固形分濃度が、０．５〜５．０質量％、好ましくは１〜４質量％とすることが好ましい。また、塗料中の含水率が１質量％以上３質量％以下になるように調整する。含水率が１質量％未満の場合、メモリー特性を十分向上することができず、３質量％以上の場合、該塗料を導電性支持体上に塗布する際にぽちやムラ等の画像欠陥が発生してしまう。
【００４５】
さらには、塗料中に添加剤等を加えても良い。
【００４６】
電荷発生層の膜厚は、０．０５〜５μｍの範囲が好ましい。
【００４７】
本発明で用いる導電性支持体は導電性を有するものであれば、いずれのものでもよく、例えばアルミニウム、銅、クロム、ニッケル、亜鉛、ステンレス等の金属をドラムまたはシート状に成型したもの、アルミニウムや銅等の金属箔をプラスチックフィルムにラミネートしたもの、アルミニウム、酸化インジウム、酸化スズ等をプラスチックフィルムに蒸着したもの、導電性物質を単独またはバインダー樹脂とともに塗布して導電層を設けた金属、プラスチックフィルム、紙等が挙げられる。
【００４８】
また、支持体上には、レーザービームプリンターなど画像入力がレーザー光の場合は、散乱による干渉縞防止、または基板の傷を被覆することを目的とした導電層を設けても良い。これは、カーボンブラック、金属粒子などの導電性粉体をバインダー樹脂に分散させて形成することができる。導電層の膜厚は５〜４０μｍ、好ましくは、１０〜３０μｍである。
【００４９】
さらに、導電性支持体上または上記導電層の上に、下引き層を設けることもできる。下引層は、ポリアミド、ポリビニルアルコール、ポリエチレンオキシド、カゼイン、エチルセルロース、ポリウレタン、ポリエーテルウレタン等によって形成できる。下引層の膜厚は０．０５〜５μｍ、好ましくは０．３〜１μｍが適当である。
【００５０】
電荷輸送層は、電荷輸送物質及びバインダー樹脂から構成される。電荷輸送物質としては、トリアリールアミン系化合物、ヒドラゾン化合物、スチルベン化合物、ピラゾリン系化合物、オキサゾール系化合物、トリアリルメタン系化合物、チアゾール系化合物等が挙げられる。
【００５１】
バインダー樹脂としてはポリカーボネート、ポリアリレート等の芳香族ポリエステル樹脂、飽和アルキルポリエステル樹脂、ポリメタクリレート、スチレン−アクリル共重合体等のアクリル樹脂、ポリスチレン、スチレンーブタジエンゴム、エチレン−酢酸ビニル共重合体、酢酸ビニル及びそれらの共重合体、ポリエチレンテレフタレート樹脂、ポリブチレンテレフタレート樹脂、ポリアセタール、ポリエーテルスルホン、ポリスルホン、ポリフェニレンサルファイド、ポリエーテルケトン、シリコーン樹脂、アクリル樹脂、ポリウレタン樹脂等を挙げることができる。バインダー樹脂が電荷輸送機能を兼ね備えてもよい。
【００５２】
電荷輸送層の厚さは５〜４０μｍ、好ましくは１０〜３５μｍである。
【００５３】
さらに、感光体の表面保護のため、感光層の上に保護層を設けることもできる。保護層に用いることのできるバインダー樹脂としては、ポリカーボネート樹脂、ポリエステル樹脂、ポリアリレート樹脂、ポリスチレン樹脂、ポリエチレン樹脂、ポリプロピレン樹脂、ポリウレタン樹脂、アクリル樹脂、エポキシ樹脂、シリコーン樹脂、セルロース樹脂、ポリ塩化ビニル樹脂、ホスファゼン樹脂、メラミン樹脂および塩化ビニル−酢酸ビニル共重合体等が挙げられる。また、保護層中には、導電性粒子として金属、金属酸化物およびカーボンブラック等を分散しても良い。金属としては、アルミニウム、亜鉛、銅、クロム、ニッケル、ステンレス、および銀等、またはこれらの金属をプラスチックの粒子の表面に蒸着したもの等が挙げられる。金属酸化物としては、酸化亜鉛、酸化チタン、酸化スズ、酸化アンチモン、酸化インジウム、酸化ビスマス、スズをドープした酸化インジウム、アンチモンをドープした酸化スズおよびアンチモンをドープした酸化ジルコニウム等が挙げられる。これらは単独で用いることも、２種以上を組み合わせて用いることもできる。
【００５４】
保護層に適する膜厚は０．２〜１０μｍ、より好ましくは０．５〜６μｍである。
【００５５】
また、電荷輸送層や保護層には耐久性を向上させるために潤滑剤として無機フィラー、ポリエチレン、ポリフルオロエチレン、シリカ等や、添加剤として分散剤、紫外線吸収剤や酸化防止剤、シリコーンオイル、レベリング剤等を添加させたりしても良い。
【００５６】
各層を塗工するコーティング法としては、浸漬コーティング法、スプレーコーティング法、ロールコーターコーティング法、グラビアコーティング法が使用できる。
【００５７】
次に本発明の電子写真感光体を用いた電子写真装置について説明する。
【００５８】
図２に本発明の電子写真感光体を有するプロセスカートリッジを備えた電子写真装置の概略構成を示す。
【００５９】
図２において、１１はドラム状の本発明の電子写真感光体であり、軸１２を中心に矢印方向に所定の周速度で回転駆動される。電子写真感光体１１は、回転過程において、一次帯電手段１３によりその周面に正又は負の所定電位の均一帯電を受け、次いで、スリット露光やレーザービーム走査露光等の露光手段（不図示）から出力される目的の画像情報の時系列電気デジタル画像信号に対応して強調変調された露光光１４を受ける。こうして電子写真感光体１１の周面に対し、目的の画像情報に対応した静電潜像が順次形成されていく。
【００６０】
形成された静電潜像は、次いで現像手段１５によりトナー現像され、不図示の給紙部から電子写真感光体１１と転写手段１６との間に電子写真感光体１１の回転と同期して取り出されて給送された転写材１７に、電子写真感光体１１の表面に形成担持されているトナー画像が転写手段１６により順次転写されていく。
【００６１】
トナー画像の転写を受けた転写材１７は、電子写真感光体面から分離されて像定着手段１８へ導入されて像定着を受けることにより画像形成物（プリント、コピー）として装置外へプリントアウトされる。
【００６２】
像転写後の電子写真感光体１１の表面は、クリーニング手段１９によって転写残りトナーの除去を受けて清浄面化され、繰り返し画像形成に使用される。
【００６３】
本発明においては、上述の電子写真感光体１１並びに、一次帯電手段１３、現像手段１５及びクリーニング手段１９等の構成要素のうち、複数のものを容器に納めてプロセスカートリッジとして一体に結合して構成し、このプロセスカートリッジを複写機やレーザービームプリンター等の電子写真装置本体に対して着脱自在に構成してもよい。例えば、一次帯電手段１３、現像手段１５及びクリーニング手段１９の少なくとも一つを電子写真感光体１１と共に一体に支持してカートリッジ化して、装置本体のレール等の案内手段２２を用いて装置本体に着脱自在なプロセスカートリッジ２１とすることができる。
【００６４】
また、露光光１４は、電子写真装置が複写機やプリンターである場合には、原稿からの反射光や透過光、あるいは、センサーで原稿を読取り、信号化し、この信号に従って行われるレーザービームの走査、ＬＥＤアレイの駆動又は液晶シャッターアレイの駆動等により照射される光である。
【００６５】
本発明の電子写真感光体は、電子写真複写機に利用するのみならず、レーザービームプリンター、ＣＲＴプリンター、ＬＥＤプリンター、ＦＡＸ、液晶プリンター及びレーザー製版等の電子写真応用分野にも広く用いることができる。
【００６６】
【実施例】
以下に本発明の実施例を説明する。なお、実施例中、「部」は質量部を示す。
【００６７】
（実施例１）
φ３０ｍｍ、長さ２６０ｍｍのアルミニウムシリンダーを支持体とし、それに以下の材料より構成される塗料を支持体上に浸漬法で導電層、下引き層、電荷発生層、電荷輸送層の順に順次塗布し、感光体を作製した。
【００６８】
導電層塗料として、
【００６９】
導電性顔料：ＳｎＯ_２コート処理硫酸バリウム　　　　　　　　　１０部
抵抗調整用顔料：酸化チタン　　　　　　　　　　　　　　　　　２部
バインダー樹脂：フェノール樹脂　　　　　　　　　　　　　　　６部
レベリング剤：シリコーンオイル　　　　　　　　　　　０．００１部
溶剤：メタノール／メトキシプロパノール＝０．２／０．８　　２０部
【００７０】
を、１ｍｍΦガラスビーズ入りサンドミル装置で２時間分散したものを調整した。この塗料を支持体上に浸漬法で塗布し、１４０℃で３０分熱硬化させ、膜厚１５μｍの導電層を形成した。
【００７１】
次にこの上に、Ｎ−メトキシメチル化ナイロン５部および共重合ナイロン１部をメタノール６５部、ｎブタノール３０部の混合溶媒に溶解した溶液を浸漬法により塗布し、膜厚０．５μｍの下引き層を形成した。
【００７２】
電荷発生塗料の調整は以下のように行った。電荷発生材料として、ＣｕＫαのＸ線回折スペクトルにおける回折角２θ±０．２°の９．０°、１４．２°、２３．９°、２７．１°に強いピークを有するオキシチタニウムフタロシアニン顔料１１部、下記アゾ顔料（化２０）４部、ポリビニルブチラール（商品名ＢＸ−１、積水化学（株）製）１０部、分散溶媒として特級テトラヒドロフラン２９４部、及び蒸留水６部をそれぞれ共に１ｍｍφガラスビーズ（ＧＢ２０１Ｍ、東芝バロティーニ（株）製）４００部を用いたサンドミル装置で、２０℃下、８時間分散した。得られた分散液を特級シクロヘキサノン３００部で希釈して塗布液を調整した。得られた塗布液の含水率をカールフィッシャー測定装置（ＡＱＶ−２００、平沼産業製）で測定したところ、１．１質量％であった。
【００７３】
【化２０】

【００７４】
この塗料を下引き層の上に浸漬法で塗布し、８０℃で１０分乾燥して膜厚０．２μｍの電荷発生層を形成した。
電荷輸送用塗料の調整は以下のように行った。初めにフッ素系樹脂粒子分散液を調製するために、
【００７５】
ビスフェノールＺ型ポリカーボネート
（商品名：Ｚ−８００、三菱ガス化学製）　　　　　　　　　　　２部
四フッ化エチレン樹脂微粒子
（ルブロンＬ−２、ダイキン工業（株）製）　　　　　　　　　　２部
フッ素系クシ型グラフトポリマー
（商品名ＧＦ３００、東亜合成化学（株）製）　　　　　　０．０６部
モノクロロベンゼン　　　　　　　　　　　　　　　　　　　　２０部
【００７６】
を充分に混合した後、ガラスビーズを用いたサンドグラインダー（（株）アイメックス製）にて分散し、４−フッ化エチレン樹脂粒子分散液を調製した。電荷輸送材料として下記構造式で示す化合物を９部、
【００７７】
【化２１】

下記構造式で示す化合物を１部、
【００７８】
【化２２】

ビスフェノールＺ型ポリカーボネート（商品名：Ｚ−８００、三菱ガス化学製）８部、及び上記４−フッ化エチレン樹脂粒子分散液２４部をジクロロメタン４０部とモノクロロベンゼン６０部の混合溶液に溶解した。この液を上記電荷発生層上に浸漬コーティング法で塗布し、１１５℃で６０分間乾燥し、膜厚が３０μｍの電荷輸送層を形成し、電子写真感光体を作製した。
【００７９】
このようにして作製した電子写真感光体は、ヒュ−レット・パッカ−ド（株）製プリンタ−Ｌａｓｅｒ　Ｊｅｔ　４０００の像露光装置を光量可変となるよう改造した装置で評価した。作製した電子写真感光体をこの装置で、暗部電位（Ｖｄ）が−７００Ｖになるように帯電し、これに波長７８０ｎｍのレーザー光を照射して明部電位（Ｖｌ）が−１５０Ｖになるのに必要な光量を測定し感度とした。電子写真感光体の表面電位は、評価機から、現像用カートリッジを抜き取り、そこに電位測定装置を挿入し測定を行った。電位測定装置は、現像用カートリッジの現像位置に電位測定プローブを配置する事で構成されており、電子写真感光体に対する電位測定プローブの位置は、ドラム軸方向のほぼ中央、ドラム表面からのギャップを３ｍｍとした。さらに印字比率６％の画像を２３℃／５５％ＲＨの雰囲気環境においてプリント１枚ごとに１回停止する間欠モードで１０，０００枚の通紙耐久をおこない、耐久前後での電位差△Ｖｄ（＝１０，０００枚耐久後のＶｄ−初期Ｖｄ）、△Ｖｌ（＝１０，０００枚耐久後のＶｌ−初期Ｖｌ）を求めた。
【００８０】
また、画像評価は次のように行った。まず、電子写真感光体の１周目部分に適当なパターンとその後全面ハーフトーンのある画像を出力し、ハーフトーン部分における１周目のパターン（ゴースト）の有無及びハーフトーンムラ等を目視で確認した。また、べた黒画像を出力し白ぽち等の画像欠陥の有無を確認した。結果を表１に示す。
【００８１】
（実施例２）
実施例１の電荷発生層の形成において、オキシチタニウムフタロシアニン顔料を７．５部、アゾ顔料を７．５部としたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。結果を表１に示す。
【００８２】
（実施例３）
実施例１の電荷発生層の形成において、オキシチタニウムフタロシアニン顔料を１１部、実施例１で用いたアゾ顔料（化２０）を３部、下記構造式のアゾ顔料（化２３）を１部としたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。結果を表１に示す。
【００８３】
【化２３】

【００８４】
（実施例４）
電荷発生層に含有するアゾ顔料を下記構造式（化２４）のものに代えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。結果を表１に示す。
【００８５】
【化２４】

（実施例５）
電荷発生層に含有するアゾ顔料を下記構造式（化２５）のものに代えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。結果を表１に示す。
【００８６】
【化２５】

【００８７】
（実施例６）
電荷発生層に含有するアゾ顔料を下記構造式（化２６）のものに代えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。結果を表１に示す。
【００８８】
【化２６】

【００８９】
（実施例７）
実施例１の電荷発生層塗料において、以下のように作製方法を変更した以外は、実施例１と同様にして電子写真感光体を作製し、評価した。
【００９０】
ＣｕＫαのＸ線回折スペクトルにおける回折角２θ±０．２°の９．０°、１４．２°、２３．９°、２７．１°に強いピークを有するオキシチタニウムフタロシアニン顔料１０部、ポリビニルブチラール（商品名ＢＸ−１、積水化学（株）製）１０部、分散溶媒として特級テトラヒドロフラン１９２部及び蒸留水８部をそれぞれ共に１ｍｍφガラスビーズ（ＧＢ２０１Ｍ、東芝バロティーニ（株）製）３００部を用いたサンドミル装置で、２０℃下、４時間分散した。次に実施例１で用いたアゾ顔料（化２０）５部、分散溶媒として特級テトラヒドロフラン９６部及び蒸留水４部を、１ｍｍφガラスビーズ（ＧＢ２０１Ｍ、東芝バロティーニ（株）製）２００部を用いた別のサンドミル装置で、２０℃下、２０時間分散した。得られた分散液を混合し、特級シクロヘキサノン３００部で希釈して塗布液を調整した。得られた塗布液の含水率をカールフィッシャー測定装置（ＡＱＶ−２００、平沼産業製）で測定したところ、２．１質量％であった。
【００９１】
（実施例８）
実施例１の電荷発生層塗料において、分散液の希釈をシクロヘキサノン２９０部及び蒸留水１０部に変えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。
【００９２】
このときの電荷発生層用塗料の含水率は、２．８質量％であった。
【００９３】
（比較例１）
実施例１の電荷発生層において、アゾ顔料を用いなかったこと以外は、実施例１と同様にして電子写真感光体を作製し、評価した。
【００９４】
（比較例２）
実施例１の電荷発生層において、アゾ顔料を用いず、更に分散溶媒を特級テトラヒドロフラン３００部に変えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。
このときの電荷発生層用塗料の含水率は０．３質量％であり、分散後のオキシチタニウムフタロシアニン顔料の結晶形はＸ線結晶形スペクトル図４に示す結晶形に変化していた。
【００９５】
（比較例３）
電荷発生層に含有するオキシチタニウムフタロシアニン顔料をＣｕＫαのＸ線回折スペクトルにおける回折角２θ±０．２°の７．６°及び２８．６°に強いピークを有するもの（Ｘ線回折スペクトル図５）に代えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。結果を表１に示す。
【００９６】
（比較例４）
実施例１の電荷発生層において、分散溶媒を特級テトラヒドロフラン２８２部及び蒸留水１８部に変えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。
【００９７】
このときの電荷発生層用塗料の含水率は、３．０質量％であった。
【００９８】
（比較例５）
実施例１の電荷発生層塗料において、分散溶媒を特級テトラヒドロフラン３００部に変えたほかは、実施例１と同様にして電子写真感光体を作製し、評価した。
【００９９】
このときの電荷発生層用塗料の含水率は、０．３質量％であった。
【０１００】
【表１】

【０１０１】
【発明の効果】
以上のように本発明によれば、高感度でかつ繰り返し使用における電位変動が小さく、メモリー特性や塗工ムラによる画像欠陥が少ない電子写真感光体、この電子写真感光体を用いた電子写真装置及び電子写真装置ユニットを提供することができる。
【図面の簡単な説明】
【図１】本発明の電子写真感光体の層構成を示す図である。
【図２】本発明の電子写真感光体を有するプロセスカートリッジを備えた電子写真装置の概略構成の例を示す図である。
【図３】本発明実施例のオキシチタニウムフタロシアニンの特性Ｘ線回折図である。
【図４】本発明比較例のオキシチタニウムフタロシアニンの特性Ｘ線回折図である。
【図５】本発明比較例のオキシチタニウムフタロシアニンの特性Ｘ線回折図である。
【符号の説明】
１　感光層
２　電荷発生層
３　電荷輸送層
４　導電性支持体
１１　電子写真感光体
１２　軸
１３　帯電手段
１４　露光光
１５　現像手段
１６　転写手段
１７　転写材
１８　定着手段
１９　クリーニング手段
２１　プロセスカートリッジ
２２　案内手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laminated electrophotographic photosensitive member containing an azo pigment and an oxytitanium phthalocyanine pigment, a process cartridge provided with the electrophotographic photosensitive member, and an electrophotographic apparatus.
[0002]
[Prior art]
In recent years, electrophotographic photoreceptors used in copiers, laser printers, and the like using electrophotography have been developed from organic photoconductor materials because of their advantages such as high safety, suitability for mass production, and low cost. The formed photoreceptor is widely used. The configuration of the organic photoreceptor includes a single-layer photoreceptor having a photosensitive layer mainly composed of a charge generating substance, a charge transporting substance and a binder resin on a conductive support, and a charge generating substance on a conductive support. And a charge transport layer mainly composed of a binder resin, a charge transport material and a charge transport layer mainly composed of a binder resin. Above all, the stacked type photoreceptor can be further improved in sensitivity, and is currently the mainstream of the organic electrophotographic photoreceptor.
[0003]
Further, in electrophotographic image formation, digitization of image formation is rapidly progressing in order to obtain high-quality images and to store and freely edit input images. When digitally forming an image, a digital electric signal is converted into an optical signal and input to a photoconductor. As this light source, laser light or LED light is mainly used. At present, the emission wavelength of the most frequently used light source is 790 ± 20 nm. With the progress of digitization, the frequency of demand for charge generation materials having sufficient sensitivity in this wavelength range has been increasing. As a typical charge generation material, a phthalocyanine compound can be mentioned, and among them, many sensitive oxytitanium phthalocyanines have been studied. Oxytitanium phthalocyanine has been reported in, for example, JP-A-61-239248, JP-A-62-67094, JP-A-1-17066, JP-A-3-54264, and JP-A-3-128973. Many crystal forms are known as described above, and oxytitanium phthalocyanine having a clear diffraction peak at 27.1 ° at a black angle (2θ ± 0.2 °) in the X-ray diffraction spectrum is very sensitive. It is clear that it is high. Further, its crystal form is a metastable form, and when preparing a dispersion for applying a charge generation layer in the process of producing a photoreceptor, it is likely to change to another stable crystal form depending on the dispersion conditions, and sensitivity characteristics are impaired. Easy to be. Therefore, Japanese Patent Application Laid-Open No. 6-289628 discloses a method of dispersing an oxytitanium phthalocyanine crystal with a solvent containing an equal amount or more of water so that a dispersion can be produced while maintaining a stable crystal form, and high sensitivity can be achieved. Is disclosed.
[0004]
[Problems to be solved by the invention]
However, the electrophotographic photoreceptor using these oxytitanium phthalocyanines has high sensitivity, so that the charging potential is reduced and the light portion potential fluctuates due to repeated image forming processes such as charging, exposure, development and transfer. In addition, there is a defect that a kind of memory is generated due to the accumulation of electric charges in the electric charge generating layer, and a ghost phenomenon in which an originally non-existent pattern appears on an image occurs.
[0005]
Further, when a water-containing paint is applied on the conductive support, image defects may occur due to uneven coating.
[0006]
Accordingly, an object of the present invention is to provide an electrophotographic photoreceptor that has low image defects and has excellent potential fluctuation due to durability and excellent memory characteristics while maintaining high sensitivity in a laminated electrophotographic photoreceptor using an oxytitanium phthalocyanine pigment. Another object of the present invention is to provide a process cartridge having the electrophotographic photosensitive member and an electrophotographic photosensitive member.
[0007]
[Means for Solving the Problems]
As a result of investigations by the present inventors, charge generation using an oxytitanium phthalocyanine pigment having a distinct peak at 27.1 ° at a diffraction angle of 2θ ± 0.2 ° in the CuKα characteristic X-ray diffraction spectrum in the charge generation layer was performed. In preparing the coating composition for the layer, the pigment is dispersed in a mixed solvent of water and an organic solvent, the water content in the coating composition is adjusted to 1% by mass or more and less than 3% by mass, and at least one azo pigment is simultaneously contained. By doing so, it was found that image defects due to memory characteristics and coating unevenness can be improved while maintaining high sensitivity, and furthermore, potential fluctuations during repeated use can be suppressed.
[0008]
It is not clear why the memory characteristics and the potential fluctuation can be kept small, but the presence of azo pigment and water in the charge generation layer at the same time makes the carrier (electrons) generated by exposure less than that of the oxytitanium phthalocyanine pigment alone. It is considered that the recombination and injection into the substrate side are smoothly performed.
[0009]
That is, in the electrophotographic photoreceptor of the present invention, in an electrophotographic photoreceptor having a charge generation layer and a charge transport layer on a conductive support, the charge generation layer comprises at least one kind of azo pigment and a light-transmissive X-ray diffraction spectrum. It contains an oxytitanium phthalocyanine pigment having a clear peak at 27.1 ° with a bending angle of 2 ± 0.2 °, and the pigment is dispersed in a mixed solvent of water and an organic solvent, and the water content is 1% by mass or more and 3% by mass. % Is formed using a paint adjusted to less than%.
[0010]
The azo pigment used in the present invention is desirably selected from the group consisting of azo pigments having a central skeleton represented by the following general formulas (1) to (5).
[0011]
General formula (1)
[0012]
Embedded image

General formula (2)
[0013]
Embedded image

General formula (3)
[0014]
Embedded image

General formula (4)
[0015]
Embedded image

General formula (5)
[0016]
Embedded image

A ₁ , A ₂ and A ₃ in the general formulas (1) to (5) represent coupler residues.
[0017]
The oxytitanium phthalocyanine pigment used in the present invention has strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° at diffraction angles 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. It is preferred to have.
[0018]
Further, the process cartridge of the present invention integrally supports the electrophotographic photoreceptor and at least one unit selected from the group consisting of a charging unit, a developing unit and a cleaning unit, and is detachable from an electrophotographic apparatus main body. It is characterized.
[0019]
Further, an electrophotographic apparatus according to the present invention includes the electrophotographic photosensitive member, a charging unit, an image exposing unit, a developing unit, and a transfer unit.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[0021]
The electrophotographic photoreceptor of the present invention is a laminated photoreceptor having a charge generation layer and a charge transport layer formed on a conductive support. FIG. 1 shows a typical layer configuration. An example in which the photosensitive layer 1 has a laminated structure of a charge generation layer 2 containing a charge generation material and a charge transport layer 3 containing a charge transport material will be described. Reference numeral 4 denotes a conductive support.
[0022]
The charge generation layer is formed by applying a charge generation paint in which an oxytitanium phthalocyanine pigment and an azo pigment, which are charge generation materials, are dispersed in a binder resin and a dispersion solvent on a conductive support.
[0023]
Oxytitanium phthalocyanine is an oxytitanium phthalocyanine having a main peak at a diffraction angle of at least 27.1 ° ± 0.2 ° in a CuKα characteristic X-ray diffraction peak, and is represented by the following structural formula.
[0024]
Embedded image

Furthermore, oxytitanium phthalocyanine having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° of the diffraction angle (2θ ± 0.2) in the CuKα characteristic X-ray diffraction peak is higher. With sensitivity, the present invention works effectively and is particularly preferred.
[0025]
The measurement of X-ray diffraction in the present invention was performed using CuKα radiation under the following conditions.
[0026]
Measuring machine used: manufactured by Mac Science, fully automatic X-ray diffractometer MXP18
X-ray tube: Cu
Tube voltage: 50 kV
Tube current: 300 mA
Scan method: 2θ / θ scan Scan speed: 4 deg. / Min
Sampling interval: 0.020 deg.
Start angle (θ): 3 deg.
Stop angle (θ): 40 deg.
Divergence slit: 0.5 deg.
Scattering slit: 0.5 deg.
Receiving slit: 0.3mm
Use of curved monochromator
As the azo pigment, those having high sensitivity to the wavelength of the light source of the electrophotographic device to be mounted are preferable for maintaining high sensitivity, and those represented by general formulas (1) to (5) are preferable.
[0028]
General formula (1)
[0029]
Embedded image

General formula (2)
[0030]
Embedded image

General formula (3)
[0031]
Embedded image

General formula (4)
[0032]
Embedded image

General formula (5)
[0033]
Embedded image

A ₁ , A ₂ and A ₃ in the general formulas (1) to (5) represent coupler residues. In the general formulas (1) to (3), the coupler residues represented by A ₁ , A ₂ and A ₃ are selected from groups represented by the following coupler residues (1) to (3); One type or a combination of two or more types may be used.
[0034]
Coupler residue (1)
[0035]
Embedded image

Coupler residue (2)
[0036]
Embedded image

Coupler residue (3)
[0037]
Embedded image

X in the coupler residues (1) to (3) represents a hydrogen atom, a halogen atom or an alkyl group.
[0038]
The ratio between the oxytitanium phthalocyanine pigment and the azo pigment is preferably in the range of 99/1 to 50/50.
[0039]
In forming the charge generation layer, when mixing the charge generation materials, the respective materials are dispersed in an appropriate binder resin and a solvent at a ratio in the above range, or the individually dispersed liquid is adjusted to a predetermined ratio. Mix. When dispersed individually, the binder resin and the solvent may be different from each other.
[0040]
Examples of the binder resin include polyamide resin, polyvinyl butyral resin, polyester resin, acrylic resin, polycarbonate resin, polyvinyl acetal resin, polystyrene resin, polyarylate resin, polyvinyl benzal resin, polyurethane, epoxy resin, and phenol resin. . The ratio of the pigment to the binder resin is in the range of 10: 1 to 1: 5, preferably 5: 1 to 1: 4 by weight. In addition, it is preferable to perform dispersion in a concentration of the pigment in the dispersion of 0.5 to 10% by mass in view of the efficiency of dispersion and post-treatment.
[0041]
The dispersion solvent may be a mixed solvent of an organic solvent and water, but the amount of water added during dispersion is preferably 1% by mass or more and less than 100% by mass based on the pigment.
[0042]
As the organic solvent, hydrophilic solvents are preferable, for example, tetrahydrofuran, n-propyl ether, ether solvents such as n-butyl ether and 1,4-dioxane, alcohol solvents such as ethanol, propanol and 2-methoxyethanol, acetone, Examples thereof include ketone solvents such as methyl ethyl ketone and cyclohexanone.
[0043]
The dispersion treatment can be performed using a milling device such as a paint shaker, a sand mill, or a ball mill, a homogenizer, an ultrasonic dispersion or a high-pressure liquid collision dispersion device, together with a dispersion medium such as glass beads, steel beads, and alumina balls. It is preferable to disperse the pigment until the dispersion particle size becomes 0.5 μm or less, more preferably 0.2 μm or less, in order to suppress image defects such as dust and fog.
[0044]
After the dispersion, the dispersion may be used as it is as a coating solution for the charge generation layer, and the concentration may be adjusted with an organic solvent or a mixed solvent of an organic solvent and water. It is preferably from 0.5 to 5.0% by mass, more preferably from 1 to 4% by mass. Further, the water content in the paint is adjusted so as to be 1% by mass or more and 3% by mass or less. When the water content is less than 1% by mass, the memory characteristics cannot be sufficiently improved. When the water content is 3% by mass or more, image defects such as spots and unevenness occur when the paint is applied on a conductive support. Resulting in.
[0045]
Further, additives and the like may be added to the paint.
[0046]
The thickness of the charge generation layer is preferably in the range of 0.05 to 5 μm.
[0047]
The conductive support used in the present invention may be any as long as it has conductivity, for example, aluminum, copper, chromium, nickel, zinc, a metal such as stainless steel, formed into a drum or sheet, aluminum Metal foil, such as copper or copper, laminated on a plastic film, aluminum, indium oxide, tin oxide, etc. deposited on a plastic film, or a metal or plastic with a conductive layer applied by applying a conductive substance alone or with a binder resin Film, paper and the like can be mentioned.
[0048]
When the image input is a laser beam, such as a laser beam printer, a conductive layer may be provided on the support for the purpose of preventing interference fringes due to scattering or covering a scratch on the substrate. This can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is 5 to 40 μm, preferably 10 to 30 μm.
[0049]
Further, an undercoat layer may be provided on the conductive support or on the conductive layer. The undercoat layer can be formed of polyamide, polyvinyl alcohol, polyethylene oxide, casein, ethyl cellulose, polyurethane, polyether urethane, or the like. The thickness of the undercoat layer is suitably from 0.05 to 5 μm, preferably from 0.3 to 1 μm.
[0050]
The charge transport layer is composed of a charge transport material and a binder resin. Examples of the charge transport material include a triarylamine compound, a hydrazone compound, a stilbene compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound.
[0051]
As the binder resin, aromatic polyester resin such as polycarbonate and polyarylate, saturated alkyl polyester resin, polymethacrylate, acrylic resin such as styrene-acryl copolymer, polystyrene, styrene butadiene rubber, ethylene-vinyl acetate copolymer, acetic acid Examples include vinyl and their copolymers, polyethylene terephthalate resin, polybutylene terephthalate resin, polyacetal, polyether sulfone, polysulfone, polyphenylene sulfide, polyether ketone, silicone resin, acrylic resin, and polyurethane resin. The binder resin may also have a charge transport function.
[0052]
The thickness of the charge transport layer is 5 to 40 μm, preferably 10 to 35 μm.
[0053]
Further, a protective layer may be provided on the photosensitive layer for protecting the surface of the photosensitive member. Examples of the binder resin that can be used for the protective layer include polycarbonate resin, polyester resin, polyarylate resin, polystyrene resin, polyethylene resin, polypropylene resin, polyurethane resin, acrylic resin, epoxy resin, silicone resin, cellulose resin, and polyvinyl chloride resin. , A phosphazene resin, a melamine resin, and a vinyl chloride-vinyl acetate copolymer. Further, a metal, a metal oxide, carbon black, or the like may be dispersed as conductive particles in the protective layer. Examples of the metal include aluminum, zinc, copper, chromium, nickel, stainless steel, silver, and the like, and those obtained by vapor-depositing these metals on the surfaces of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony-doped tin oxide, and antimony-doped zirconium oxide. These can be used alone or in combination of two or more.
[0054]
The film thickness suitable for the protective layer is 0.2 to 10 μm, more preferably 0.5 to 6 μm.
[0055]
In addition, the charge transport layer and the protective layer include inorganic fillers, polyethylene, polyfluoroethylene, silica, and the like as lubricants to improve durability, and dispersants, ultraviolet absorbers, antioxidants, and silicone oils as additives. A leveling agent or the like may be added.
[0056]
As a coating method for coating each layer, a dip coating method, a spray coating method, a roll coater coating method, and a gravure coating method can be used.
[0057]
Next, an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention will be described.
[0058]
FIG. 2 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.
[0059]
In FIG. 2, reference numeral 11 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around an axis 12 in a direction of an arrow at a predetermined peripheral speed. The electrophotographic photoreceptor 11 receives a uniform charge of a predetermined positive or negative potential on its peripheral surface by the primary charging means 13 during the rotation process, and then receives light from exposure means (not shown) such as slit exposure or laser beam scanning exposure. It receives exposure light 14 that is enhanced and modulated according to the time-series electric digital image signal of the target image information to be output. In this way, an electrostatic latent image corresponding to the target image information is sequentially formed on the peripheral surface of the electrophotographic photosensitive member 11.
[0060]
The formed electrostatic latent image is then developed with toner by a developing unit 15 and taken out from a paper feeding unit (not shown) between the electrophotographic photoconductor 11 and the transfer unit 16 in synchronization with the rotation of the electrophotographic photoconductor 11. The toner images formed and carried on the surface of the electrophotographic photosensitive member 11 are sequentially transferred by the transfer means 16 to the transfer material 17 fed and fed.
[0061]
The transfer material 17 to which the toner image has been transferred is separated from the surface of the electrophotographic photoreceptor, introduced into the image fixing means 18 and subjected to image fixing to be printed out as an image formed product (print, copy) outside the apparatus. .
[0062]
The surface of the electrophotographic photoreceptor 11 after the image transfer is cleaned and cleaned to remove the untransferred toner by the cleaning means 19, and is repeatedly used for image formation.
[0063]
In the present invention, a plurality of components among the above-described electrophotographic photoreceptor 11 and components such as the primary charging unit 13, the developing unit 15, and the cleaning unit 19 are housed in a container and integrally combined as a process cartridge. However, the process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 13, the developing unit 15, and the cleaning unit 19 is integrally supported with the electrophotographic photosensitive member 11 to form a cartridge, and the cartridge is attached to and detached from the apparatus main body using the guide means 22 such as a rail of the apparatus main body. A flexible process cartridge 21 can be provided.
[0064]
When the electrophotographic apparatus is a copying machine or a printer, the exposure light 14 is reflected light or transmitted light from the original, or the original is read by a sensor, converted into a signal, and scanned by a laser beam performed in accordance with the signal. , Light emitted by driving an LED array or driving a liquid crystal shutter array.
[0065]
The electrophotographic photoreceptor of the present invention can be widely used not only for electrophotographic copying machines but also for electrophotographic applications such as laser beam printers, CRT printers, LED printers, faxes, liquid crystal printers, and laser plate making. .
[0066]
【Example】
Hereinafter, examples of the present invention will be described. In the examples, "parts" indicates parts by mass.
[0067]
(Example 1)
An aluminum cylinder having a diameter of 30 mm and a length of 260 mm is used as a support, and a coating composed of the following materials is sequentially applied to the support by a dipping method in the order of a conductive layer, an undercoat layer, a charge generation layer, and a charge transport layer. A photoreceptor was prepared.
[0068]
As conductive layer paint,
[0069]
Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: titanium oxide 2 parts Binder resin: phenol resin 6 parts Leveling agent: silicone oil 0.001 parts Solvent: methanol / methoxypropanol = 0.2 / 0. 8 20 copies
Was dispersed in a sand mill containing 1 mmφ glass beads for 2 hours. This coating material was applied on a support by a dipping method, and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.
[0071]
Next, a solution prepared by dissolving 5 parts of N-methoxymethylated nylon and 1 part of copolymerized nylon in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol was applied thereon by a dipping method. A pull layer was formed.
[0072]
Adjustment of the charge generation paint was performed as follows. Oxytitanium phthalocyanine pigment 11 having a strong peak at 9.0 °, 14.2 °, 23.9 °, 27.1 ° at a diffraction angle of 2θ ± 0.2 ° in the X-ray diffraction spectrum of CuKα as a charge generating material 11 Parts, the following azo pigment (Chemical Formula 20), 4 parts of polyvinyl butyral (trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.), 294 parts of special grade tetrahydrofuran as a dispersing solvent, and 6 parts of distilled water were each 1 mmφ glass beads. (GB201M, manufactured by Toshiba Barotini Co., Ltd.) The dispersion was carried out at 20 ° C. for 8 hours with a sand mill using 400 parts. The resulting dispersion was diluted with 300 parts of special grade cyclohexanone to prepare a coating solution. The water content of the obtained coating liquid was measured by a Karl Fischer measuring apparatus (AQV-200, manufactured by Hiranuma Sangyo) and found to be 1.1% by mass.
[0073]
Embedded image

[0074]
This paint was applied on the undercoat layer by an immersion method, and dried at 80 ° C. for 10 minutes to form a 0.2 μm-thick charge generation layer.
The preparation of the charge transport coating was performed as follows. First, to prepare a fluororesin particle dispersion,
[0075]
Bisphenol Z-type polycarbonate (trade name: Z-800, manufactured by Mitsubishi Gas Chemical) 2 parts fine particles of ethylene tetrafluoride resin (Rublon L-2, manufactured by Daikin Industries, Ltd.) 2 parts fluorinated comb type graft polymer (trade name: GF300) , Manufactured by Toa Gosei Chemical Co., Ltd.) 0.06 parts Monochlorobenzene 20 parts
Was thoroughly mixed and dispersed by a sand grinder (manufactured by Imex Co., Ltd.) using glass beads to prepare a dispersion of 4-fluoroethylene resin particles. 9 parts of a compound represented by the following structural formula as a charge transport material,
[0077]
Embedded image

1 part of a compound represented by the following structural formula,
[0078]
Embedded image

8 parts of bisphenol Z-type polycarbonate (trade name: Z-800, manufactured by Mitsubishi Gas Chemical) and 24 parts of the above 4-fluoroethylene resin particle dispersion were dissolved in a mixed solution of 40 parts of dichloromethane and 60 parts of monochlorobenzene. This solution was applied on the charge generation layer by dip coating, and dried at 115 ° C. for 60 minutes to form a charge transport layer having a thickness of 30 μm, thereby producing an electrophotographic photoreceptor.
[0079]
The electrophotographic photoreceptor thus manufactured was evaluated with an apparatus obtained by modifying an image exposing apparatus of a printer, Laser Jet 4000, manufactured by Hewlett-Packard Co., Ltd. so as to make the light amount variable. The prepared electrophotographic photoreceptor is charged by this apparatus so that the dark part potential (Vd) becomes -700 V, and the laser light having a wavelength of 780 nm is irradiated to the charged part, so that the light part potential (Vl) becomes -150 V. The required amount of light was measured and used as the sensitivity. The surface potential of the electrophotographic photoreceptor was measured by extracting the developing cartridge from the evaluator and inserting a potential measuring device therein. The potential measuring device is configured by arranging a potential measuring probe at a developing position of a developing cartridge.The position of the potential measuring probe with respect to the electrophotographic photosensitive member is substantially the center in the drum axis direction, and a gap from the drum surface is set. 3 mm. Further, in an intermittent mode in which an image having a printing ratio of 6% is stopped once for each print in an atmosphere environment of 23 ° C./55% RH, 10,000 sheets of paper are passed, and the potential difference ΔVd (= Vd after 10,000 sheets durability-initial Vd) and ΔVl (= Vl after 10,000 sheets durability-initial Vl) were determined.
[0080]
The image evaluation was performed as follows. First, an image having an appropriate pattern on the first lap of the electrophotographic photoreceptor and a halftone image thereafter is output, and the presence or absence of the first lap pattern (ghost) and halftone unevenness in the halftone portion are visually checked. did. Further, a solid black image was output, and the presence or absence of image defects such as white spots was confirmed. Table 1 shows the results.
[0081]
(Example 2)
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1, except that the oxytitanium phthalocyanine pigment was 7.5 parts and the azo pigment was 7.5 parts in forming the charge generation layer of Example 1. . Table 1 shows the results.
[0082]
(Example 3)
In the formation of the charge generation layer of Example 1, 11 parts of the oxytitanium phthalocyanine pigment, 3 parts of the azo pigment (Chemical Formula 20) used in Example 1, and 1 part of the azo pigment of the following structural formula (Chemical Formula 23) were used. Otherwise, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1. Table 1 shows the results.
[0083]
Embedded image

[0084]
(Example 4)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the azo pigment contained in the charge generation layer was changed to that of the following structural formula (Formula 24). Table 1 shows the results.
[0085]
Embedded image

(Example 5)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the azo pigment contained in the charge generation layer was changed to that of the following structural formula (Formula 25). Table 1 shows the results.
[0086]
Embedded image

[0087]
(Example 6)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the azo pigment contained in the charge generation layer was changed to that of the following structural formula (Formula 26). Table 1 shows the results.
[0088]
Embedded image

[0089]
(Example 7)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the preparation method was changed as follows in the charge generation layer coating material of Example 1.
[0090]
10 parts of an oxytitanium phthalocyanine pigment having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° at diffraction angles 2θ ± 0.2 ° in the X-ray diffraction spectrum of CuKα, 10 parts of polyvinyl butyral ( Sand mill using 10 parts of BX-1 (trade name, manufactured by Sekisui Chemical Co., Ltd.), 192 parts of special grade tetrahydrofuran and 8 parts of distilled water as dispersion solvents, each using 300 parts of 1 mmφ glass beads (GB201M, manufactured by Toshiba Barotini Co., Ltd.). The mixture was dispersed at 20 ° C. for 4 hours using an apparatus. Next, 5 parts of the azo pigment (Chemical Formula 20) used in Example 1, 96 parts of special grade tetrahydrofuran and 4 parts of distilled water as dispersion solvents, and 200 parts of 1 mmφ glass beads (GB201M, manufactured by Toshiba Barotini Co., Ltd.) were used. Was dispersed at 20 ° C. for 20 hours using a sand mill. The obtained dispersion was mixed and diluted with 300 parts of special grade cyclohexanone to prepare a coating liquid. The water content of the obtained coating solution was measured by a Karl Fischer measuring apparatus (AQV-200, manufactured by Hiranuma Sangyo) and found to be 2.1% by mass.
[0091]
(Example 8)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the dispersion of the charge generation layer coating material of Example 1 was changed to 290 parts of cyclohexanone and 10 parts of distilled water.
[0092]
At this time, the water content of the charge generation layer coating material was 2.8% by mass.
[0093]
(Comparative Example 1)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that no azo pigment was used in the charge generation layer of Example 1.
[0094]
(Comparative Example 2)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the azo pigment was not used in the charge generation layer of Example 1 and the dispersion solvent was changed to 300 parts of special grade tetrahydrofuran.
At this time, the water content of the coating material for the charge generation layer was 0.3% by mass, and the crystal form of the oxytitanium phthalocyanine pigment after dispersion had changed to the crystal form shown in X-ray crystal form spectrum diagram FIG.
[0095]
(Comparative Example 3)
Oxytitanium phthalocyanine pigment contained in the charge generation layer having strong peaks at 7.6 ° and 28.6 ° at a diffraction angle of 2θ ± 0.2 ° in the X-ray diffraction spectrum of CuKα (X-ray diffraction spectrum FIG. 5) An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except for changing the above. Table 1 shows the results.
[0096]
(Comparative Example 4)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the dispersion solvent in the charge generation layer of Example 1 was changed to 282 parts of special grade tetrahydrofuran and 18 parts of distilled water.
[0097]
At this time, the water content of the coating for the charge generation layer was 3.0% by mass.
[0098]
(Comparative Example 5)
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the dispersion solvent in the charge generation layer coating material of Example 1 was changed to 300 parts of special grade tetrahydrofuran.
[0099]
At this time, the water content of the charge generation layer coating material was 0.3% by mass.
[0100]
[Table 1]

[0101]
【The invention's effect】
As described above, according to the present invention, an electrophotographic photoreceptor having high sensitivity and a small potential fluctuation in repeated use, and having few image defects due to memory characteristics and coating unevenness, an electrophotographic apparatus using the electrophotographic photoreceptor, An electrophotographic apparatus unit can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a layer configuration of an electrophotographic photosensitive member of the present invention.
FIG. 2 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having an electrophotographic photosensitive member of the present invention.
FIG. 3 is a characteristic X-ray diffraction diagram of the oxytitanium phthalocyanine of the example of the present invention.
FIG. 4 is a characteristic X-ray diffraction diagram of oxytitanium phthalocyanine of a comparative example of the present invention.
FIG. 5 is a characteristic X-ray diffraction diagram of oxytitanium phthalocyanine of a comparative example of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 photosensitive layer 2 charge generation layer 3 charge transport layer 4 conductive support 11 electrophotographic photosensitive member 12 shaft 13 charging means 14 exposure light 15 developing means 16 transfer means 17 transfer material 18 fixing means 19 cleaning means 21 process cartridge 22 guide means

Claims (5)

In an electrophotographic photoreceptor having a charge generation layer and a charge transport layer on a conductive support, the charge generation layer has at least one azo pigment and a diffraction angle 2θ ± 0.2 ° in a CuKα characteristic X-ray diffraction spectrum. A paint containing an oxytitanium phthalocyanine pigment having a clear peak at 27.1 °, and dispersing the pigment in a mixed solvent of water and an organic solvent, and adjusting the water content to 1% by mass or more and less than 3% by mass. An electrophotographic photosensitive member characterized by being formed by: The azo pigment is represented by the following general formulas (1) to (5)
General formula (1)

General formula (2)

General formula (3)

General formula (4)

General formula (5)

(A ₁ , A ₂ , and A ₃ in the general formulas (1) to (5) represent coupler residues.)
The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is selected from the group consisting of azo pigments having a central skeleton shown in (1). The oxytitanium phthalocyanine pigment has a strong peak at 9.0 °, 14.2 °, 23.9 °, and 27.1 ° at a diffraction angle of 2θ ± 0.2 ° in an X-ray diffraction spectrum. The electrophotographic photosensitive member according to claim 1. An electrophotographic photosensitive member according to any one of claims 1 to 3, and at least one unit selected from the group consisting of a charging unit, a developing unit, and a cleaning unit are integrally supported and detachably attached to an electrophotographic apparatus main body. A process cartridge. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, a developing unit, and a transfer unit.

Images