JP3805387B2 - Electrophotographic photoreceptor - Google Patents

Description

【００１７】
（式中、Ｘはハロゲン原子を表し、ｎは０から１までの数を表す。）
で示されるものが挙げられる。
前記一般式〔Ｐｃ〕において、Ｘが塩素原子でｎが０から０．５までのものが好ましい。本発明の用いるオキシチタニウムフタロシアニンは、従来より公知の方法、例えば１，２−ジシアノベンゼン（オルソフタロジニトリル）とチタン化合物から、下記（１）または（２）に示す反応式にしたがって容易に合成することができる。
【００１８】
【化４】

【００１９】
すなわち、１，２−ジシアノベンゼンとチタンのハロゲン化物を、不活性溶剤中で加熱し反応させる。チタン化合物としては、四塩化チタン、三塩化チタン、四臭化チタン等を用いることができる。不活性溶剤としてはトリクロロベンゼン、α−クロロナフタレン、β−クロロナフタレン、α−メチルナフタレン、メトキシナフタレン、ジフェニルエーテル、ジフェニルメタン、ジフェニルエタン、エチレングリコールジアルキルエーテル、ジエチレングリコールジアルキルエーテル、トリエチレングリコールジアルキルエーテル等の反応に不活性な高沸点有機溶剤が好ましい。反応温度は通常１５０〜３００℃、特に１８０〜２５０℃が好ましい。反応後生成したジクロロチタニウムフタロシアニンを濾別し、反応に用いた溶剤で洗浄し反応時に生成した不純物や未反応の原料を除く。
【００２０】
次にメタノール、エタノール、イソプロピルアルコール等のアルコール類、テトラヒドロフラン、ジエチルエーテル等のエーテル類等の不活性溶剤で洗浄し反応に用いた溶剤を除去する。次いで得られたジクロロチタニウムフタロシアニンは加水分解することによりオキシチタニウムフタロシアニンとなる。
【００２１】
次いで得られたオキシチタニウムフタロシアニンを、例えば特開昭６２−６７０９４で開示している熱水処理や特開平２−２１５８６６で開示している機械的摩砕処理を行うことにより目的の結晶型を得ることができる。また、本発明で使用される結晶型オキシチタニウムフタロシアニンは、上記の製造方法により製造される結晶型オキシチタニウムフタロシアニンのみに限定されるものではなく、例えば、他の結晶型オキシチタニウムフタロシアニンからも適当な処理により製造可能であって、いかなる製造方法により製造されるオキシチタニウムフタロシアニンであってもよく、特に、そのＸ線回折スペクトルにおいて、ブラッグ角（２θ±０．２°）が２７．３°に明瞭な回折ピークを示し、図１にＸ線回折スペクトルを示した結晶型と結晶学的に同じ結晶型に属するもの（ただし、通常は２７．３°以外、９．５°付近２４．１°にも比較的明瞭な回折ピークを示す。以下、フタロシアニンと呼ぶ）が好ましい。
【００２２】
本発明に係る下記一般式〔Ｉ〕で示されるビスアゾ顔料において、
一般式〔Ｉ〕
【００２３】
【化５】

【００２４】
Ａは下記一般式〔II〕で示されるカップラーの残基を示し、ＢはＡとは異なるフェノール性水酸基を有するカップラーの残基を示す。
一般式〔II〕
【００２５】
【化６】

【００２６】
上記〔II〕式中で、Ｑは置換基を有していてもよい芳香族炭化水素の２価の基、または置換基を有していてもよい複素環の２価の基を示す。
さらにこのアゾ化合物を詳細に説明すると、上記一般式〔Ｉ〕において、アゾ基に結合するＡとＢとは相異なるカップラー残基を示す。Ａは一般式〔II〕のカップラーがジアゾニウム塩とカップリング反応により結合したカップラー残基を示し、一般式〔II〕において、Ｑは置換基を有していてもよい芳香族炭化水素の２価の基、または置換基を有していてもよい複素環の２価の基を示す。芳香族炭化水素の２価の基としては、例えば、ｏ−フェニレン基等の単環式芳香族炭化水素の２価の基、ｏ−ナフチレン基、１，８−ナフチレン基、１，２−アントラキノニレン基、９，１０−フェナントリレン基等の縮合多環式芳香族炭化水素の２価の基等が挙げられる。
【００２７】
また、複素環の２価の基としては、例えば、３，４−ピラゾールジイル基、２，３−ピリジンジイル基、３，４−ピリジンジイル基、４，５−ピリミジンジイル基、６，７−インダゾールジイル基、５，６−ベンズイミダゾールジイル基、５，６−キノリンジイル基等の複素環の２価の基等が挙げられる。
【００２８】
これら芳香族炭化水素の２価基および複素環の２価基は置換基を有していてもよい。例えば、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、ｉ−ブチル基、ヘキシル基等のアルキル基；トリフルオルメチル基；メトキシ基、エトキシ基、プロポキシ基、ブトキシ基等のアルコキシ基；ヒドロキシル基；ニトロ基；シアノ基；アミノ基；ジメチルアミノ基、ジエチルアミノ基、ジベンジルアミノ基等の置換アミノ基；フッ素原子、塩素原子、臭素原子、ヨウ素原子等のハロゲン原子；カルボキシル基；エトキシカルボニル基等のアルコキシカルボニル基；カルバモイル基；アセチル基、ベンゾイル基等のアシル基；フェノキシ基等のアリーロキシ基；ベンジルオキシ基等のアリールアルコキシ基；フェニロキシカルボニル基等のアリーロキシカルボニル基等が挙げられる。中でもアルキル基、アルコキシ基、ニトロ基、ハロゲン原子、ヒドロキシル基、カルバモイル基、特に、メチル基、メトキシ基、ニトロ基、塩素原子、ヒドロキシル基が好適である。
【００２９】
ＢはＡとは異なるフェノール性水酸基を有するカップラーの残基を示し、ジアゾニウム塩とカップリング反応するカップラーはいずれでも用いることができる。
フェノール性水酸基とは、芳香族炭化水素環に置換した水酸基のことであり、この芳香族炭化水素環にさらに、炭化水素環あるいは複素環が縮合してもよい。
【００３０】
Ｂとしては、Ａとは異なる一般式〔II〕のカップラーを用いることもできるが、特に下記一般式〔III 〕で示されるカップラーの残基が好ましい。
一般式〔III 〕
【００３１】
【化７】

【００３２】
（上記式中でＲ₁ およびＲ₂ は、それぞれ独立して水素原子、置換基を有していてもよい低級アルキル基、アリール基または複素環基を示し、Ｒ₁ とＲ₂ は互いに結合して環を形成していてもよい。Ｚはベンゼン環と縮合して、芳香族炭化水素環または複素環となるのに要する２価の基を示す。）
上記一般式〔III 〕における置換基の例をいくつか示すと、置換基を有していてもよい低級アルキル基としては、メチル基、エチル基、ｎ−プロピル基、ｎ−ブチル基、ｉ−ブチル基、ｔｅｒｔ−ブチル基、ヘキシル基等が挙げられる。アリール基としては、フェニル基、フェナントリル基、アントラキノリル基、アセナフチル基、フルオレニル基、ビフェニリル基、ｐ−ターフェニリル基、ｐ−スチリルフェニル基等の芳香族炭化水素基が挙げられ、これらの置換基としては、メチル基、エチル基、ブチル基等のアルキル基；フッ素、塩素、臭素、ヨウ素等のハロゲン原子；メトキシ基、エトキシ基、ブトキシ基等のアルコキシ基；フェノキシ基等のアリーロキシ基；ヒドロキシ基；ニトロ基；シアノ基；アミノ基；ジメチルアミノ基、ジエチルアミノ基、ジベンジルアミノ基等の置換アミノ基；カルボキシル基；エトキシカルボニル基等のアルコキシカルボニル基；フェニロキシカルボニル基等のアリーロキシカルボニル基；アセトキシ基、ベンゾイルオキシ基等のアシロキシ基；アセチル基、ベンゾイル基等のアシル基；カルバモイル基、ジメチルアミノカルボニル基、フェニルアミノカルボニル基等の置換アミノカルボニル基；ベンジルオキシ基、フェネチルオキシ基等のアリールアルコキシ基等が挙げられる。
【００３３】
複素環基としては、フリル基、チエニル基、チアゾリル基、インドリル基、ピロリル基、カルバゾリル基、ピリジル基、モルホリノ基、キノリル基、イミダゾリル基、オキサゾリル基、トリアゾリル基、ピペリジル基、ベンゾオキサゾリル基、ベンゾイミダゾリル基、ベンゾチアゾリル基、アクリジル基、キサンテニル基、フェナジニル基、フェノチアジニル基、クマリニル基等が挙げられ、アリール基と同様の置換基を有していてもよい。
【００３４】
Ｚとしては、ベンゼン環と縮合してナフタリン環、アントラセン環、カルバゾール環、ベンゾカルバゾール環、ジベンゾフラン環等の芳香族炭化水素または複素環となるのに要する２価の基が挙げられる。
Ｒ₁ とＲ₂ が、互いに結合して環を形成する基の例としては、シクロヘキシリデン基、インデニリデン基、フルオロニリデン基、ペンタメチレン基等が挙げられる。
【００３５】
以上の一般式〔II〕および〔III 〕で示されるカップラーの構造式のそれぞれの具体例のいくつかを下記表１，２に各々示す。なお、当然ながら、本発明は、これらの具体例のみに限定されるものではない。
【００３６】
【表１】

【００３７】
【表２】

【００３８】
【表３】

【００３９】
【表４】

【００４０】
これらのカップラーは、Ａ−１，Ａ−２に見られるように２種類の異性体があるが、わかりやすくするためにＡ−３以降ではこれらの一方の異性体の例のみを示した。
【００４１】
【表５】

【００４２】
【表６】

【００４３】
【表７】

【００４４】
【表８】

【００４５】
【表９】

【００４６】
【表１０】

【００４７】
【表１１】

【００４８】
【表１２】

【００４９】
【表１３】

【００５０】
【表１４】

【００５１】
【表１５】

【００５２】
【表１６】

【００５３】
【表１７】

【００５４】
【表１８】

【００５５】
【表１９】

【００５６】
【表２０】

【００５７】
【表２１】

【００５８】
【表２２】

【００５９】
【表２３】

【００６０】
【表２４】

【００６１】
【表２５】

【００６２】
【表２６】

【００６３】
【表２７】

【００６４】
【表２８】

【００６５】
【表２９】

【００６６】
【表３０】

【００６７】
【表３１】

【００６８】
本発明に係るビスアゾ顔料は例えば特開昭６３−１９５６５７号公報中の製造例１，２，３に準拠して製造できるが、大略は以下の行程である。
【００６９】
【化８】

【００７０】
本発明に係るビスアゾ顔料一般式〔Ｉ〕は、４５０ｎｍ〜６００ｎｍの領域で感度が高く、本発明に用いるフタロシアニンの低感度スペクトル領域の感度を補うものであり、本発明に係るフタロシアニン顔料と併用することにより短波長域から長波長域にかけて幅広く感度を持ち、さらに、ビスアゾ顔料とフタロシアニンの混合比率を変えることにより容易に感度を調整することができるという特徴を有する。
【００７１】
このような異種のキャリア発生物質の併用は、必ずしも一律的な選択手段があるというものでもなく、本発明においても数多くの化合物の中から実験の積み重ねによって前記フタロシアニン顔料とビスアゾ顔料の組み合わせを決定したものである。
【００７２】
本発明の感光体によれば可視域で主たる分光感度が必要な複写機（例えば蛍光灯、ハロゲンランプ、キセノンランプ等の画像信号即ちアナログ信号）として好適であり、かつ可視光領域中の長波長側あるいは近赤外域で分光感度が必要なプリンタ（例えば発光ダイオード、Ｈｅ−Ｎｅレーザー等の気体レーザー、半導体レーザー等の画像信号即ちデジタル信号）としても好適となる。この意味でアナログ／デジタルの両方式をそれぞれ実現できる。
【００７３】
次に感光層を塗布するための塗布液の製造方法としては、(1) フタロシアニンとビスアゾ顔料を別の感光層に用いる場合には、フタロシアニンおよびビスアゾ顔料をそれぞれ別の分散媒中で分散処理し、更に結着樹脂と混合された状態に調整し、それぞれの塗布法とし、(2) フタロシアニンとビスアゾ顔料を同じ層に用いる場合はこれらのフタロシアニンおよびビスアゾ顔料を混合して分散媒中で分散処理し、最終的に結着樹脂と混合された状態で感光層を塗布するための塗布液として調整する、或いは、フタロシアニンおよびビスアゾ顔料をそれぞれ分散媒中で分散処理し、さらに結着樹脂と混合された状態に調整し塗布液として用いるか、それぞれ調整された液を混合して塗布液とする。
【００７４】
分散媒としては、種々の溶媒を用いて良い。例えば、ジエチルエーテル、ジメトキシメタン、テトラヒドロフラン、１，２−ジメトキシエタン等のエーテル類；アセトン、メチルエチルケトン等のケトン類；酢酸メチル、酢酸エチル等のエステル類；メタノール、エタノール、プロパノール等のアルコール類を単独あるいは２種以上混合して使用することができる。
【００７５】
結着樹脂としてはポリビニルブチラール、ポリビニルアセタール、ポリエステル、ポリカーボネート、ポリスチレン、ポリエステルカーボネート、ポリスルホン、ポリイミド、ポリメチルメタクリレート、ポリ塩化ビニル等のビニル重合体、及びその共重合体、フェノキシ、エポキシ、シリコーン樹脂等またこれらの部分的架橋硬化物等を単独あるいは２種以上用いることができる。
【００７６】
フタロシアニンおよびビスアゾ顔料を分散処理する方法としては、公知の方法例えばボールミル、サンドグラインドミル、遊星ミル、ロールミル等の方法を用いることができる。
結着樹脂とフタロシアニンおよび／またはビスアゾ顔料粒子との混合方法としては、例えば、フタロシアニンおよびビスアゾ顔料粒子を分散処理中に結着樹脂を粉末のままあるいはそのポリマー溶液を加え同時に分散する方法、分散液を結着樹脂のポリマー溶液中に混合する方法、あるいは逆に分散液中にポリマー溶液を混合する方法等のいずれの方法を用いてもかまわない。
【００７７】
フタロシアニンとビスアゾ顔料を混合して用いる場合の含有比率は、フタロシアニンが１重量部に対して、通常、ビスアゾ顔料が０．０５重量部〜１０重量部の範囲より使用される。フタロシアニンおよびビスアゾ顔料をそれぞれ別々に分散媒中で分散処理し、さらに結着樹脂と混合された状態に調整し、それぞれ調整された液を混合して感光層を塗布するための塗布液とする場合のそれぞれ調整された液の混合方法は、メカニカルスターラー、ホモミキサー、ホモジナイザーなどを用いて混合する、あるいは、超音波を印加して混合する、その他、公知のいずれの方法を用いても差し支えない。
【００７８】
次にここで得られた分散液は、塗布をするのに適した液物性にするために、種々の溶剤を用いて希釈してもかまわない。この溶剤としては、例えば前記分散媒として例示した溶媒を使用することができる。フタロシアニンおよび／またはビスアゾ顔料と結着樹脂との割合は特に制限はないが一般的には樹脂１００重量部に対してフタロシアニンおよび／またはビスアゾ顔料の総量が５〜５００重量部の範囲より使用される。また、この分散液において、フタロシアニンおよび／またはビスアゾ顔料の濃度は、０．１重量％から１０重量％の範囲で使用されることが好ましい。
【００７９】
また必要に応じて電荷移動剤を含むことができる。電荷移動剤としては例えば、２，４，７−トリニトロフルオレノン、テトラシアノキシジメタン等の電子吸引性物質、カルバゾール、インドール、イミダゾール、オキサゾール、オキサジアゾール、ピラゾリン、チアゾールなどの複素環化合物、アニリン誘導体、ヒドラゾン化合物、芳香族アミン誘導体、スチルベン誘導体、あるいはこれらの化合物からなる基を主鎖もしくは側鎖に有する重合体等の電子供与性物質が挙げられる。電荷移動剤と結着樹脂の割合は結着樹脂１００重量部に対して電荷移動剤が５〜５００重量部の範囲より使用される。
【００８０】
フタロシアニンとビスアゾ顔料を混合して用いる場合には、この様にして調整された混合分散液を用いて、導電性支持体上に電荷発生層を形成させ、その上に電荷移動層を積層させて感光層を形成する、或いは、導電性支持体上に電荷移動層を形成しその上に前記混合分散液を用いて電荷発生層を形成し感光層を形成する、或いは、導電性支持体上に前記混合分散液を用いて電荷発生層を形成させ感光層とする、のいずれかの構造で感光層を形成することができる。フタロシアニンとビスアゾ顔料を別々の層で用いる場合には、導電性支持体上に第１の電荷発生層を形成させ、その上に第２の電荷発生層を形成させ、さらにその上に電荷移動層を積層させた感光層、或いは、導電性支持体上に電荷移動層を形成し、その上に第２の電荷発生層を形成し、さらにその上に第１の電荷発生層を積層させた感光層、或いは、導電性支持体上に第１の電荷発生層を形成し、その上に第２の電荷発生層を積層させた感光層のいずれの構造も取ることができる。フタロシアニン或いはビスアゾ顔料は前記第１の電荷発生層或いは第２の電荷発生層のいずれに用いてもよい。電荷発生層の膜厚は電荷移動層と積層させて感光層を形成する場合０．１μｍ〜１０μｍの範囲が好適であり電荷移動層の膜厚は５μｍ〜６０μｍが好適である。電荷発生層のみの単独構造、或いは、２層の電荷発生層で感光層を形成する場合の感光層の膜厚は５μｍ〜６０μｍの範囲が好適である。
【００８１】
電荷移動層を設ける場合、そこに使用される電荷移動剤としては、前記電荷移動剤として例示した材料を使用することができる。これら電荷移動剤とともに必要に応じて結着樹脂が配合される。結着樹脂としては、例えば前記結着樹脂として例示したものを使用することができる。感光層には、必要に応じて酸化防止剤、増感剤等の各種添加剤を含んでいても良い。
【００８２】
感光層は、導電性支持体上に設けられるが導電性支持体としては、公知のものから選択でき、アルミニウム、ステンレス鋼、ニッケル等の金属材料、表面にアルミニウム、銅、パラジウム、酸化スズ、酸化インジウム等の導電性層を設けたポリエステルフィルム、紙、ガラス等の絶縁性支持体が使用される。
【００８３】
導電性支持体と感光層の間には通常使用されるような公知のバリアー層が設けられていても良い。バリアー層としては、例えばアルミニウム陽極酸化被膜、酸化アルミニウム、水酸化アルミニウム等の無機層、ポリビニルアルコール、カゼイン、ポリビニルピロリドン、ポリアクリル酸、セルロース類、ゼラチン、デンプン、ポリウレタン、ポリイミド、ポリアミド、等の有機層が使用される。バリアー層の膜厚は０．１μｍから２０μｍの範囲が好ましく、０．１μｍから１０μｍの範囲で使用されるのが最も効果的である。
【００８４】
次に本発明の感光体１を用いた画像形成装置の一例を図２に示す。ここで２は帯電極、３は長波長光用光源、４は短波長光用（可視光）光源、５は現像器、７は転写電極、８は分離電極、９はクリーニングブレード、１０は除電ランプである。
また、光源３，４に使用可能な光源としては、白色光、ハロゲンランプ光、タングステンランプ光、蛍光灯光やレーザー光（半導体レーザー、Ｈｅ−Ｎｅレーザー）ＬＥＤ等が挙げられる。
【００８５】
現像器５は、通常の順現像法、あるいは反転現像法のいずれでもよい。除電ランプ１０は、順現像時、反転現像時のいずれにおいても有効である。
画像形成に際しては、まず白色光源を使用する場合は、２で帯電された感光体は４で画像露光され、５で現像される。これを７の転写電極で転写紙６に転写し、８の分離電極で転写紙を分離する。感光体１に残ったトナーは９で掻き落とし、クリーニングされる。
【００８６】
一方、レーザー光源を用いた場合は、２で帯電された感光体は３で画像露光され、５で現像される。これを７の転写電極で転写紙６に転写し、８の分離電極で転写紙を分離する。感光体１に残ったトナーは９で掻き落とし、クリーニングされる。
この画像形成装置のように、ドラム状の感光体を用いるものについては、レーザー光源による画像露光は、図３に示すようなレーザービームスキャナによるものが好ましい。
【００８７】
次に図３のレーザービームスキャナの作動を述べる。
半導体レーザー２１で発生されたレーザービームは、駆動モーター２２により回転されるポリゴンミラー２３により所定振幅角内で左右に振られ、ｆ−θレンズ２４を経て反射鏡２５により光路を曲げられ感光体１の表面上に投射され線２６上を走査する。
【００８８】
２７はビーム走査開始を検出するインデックスセンサで、２８，２９は倒れ角補正用のシンドリカルレンズである。３０，３１，３２は反射鏡でビーム走査光路およびビーム検知の光路を形成する。
走査が開始されるとビームがインデックスセンサ２７によって検知され、信号によるビームの変調が図示省略した変調部によって開始される。変調されたビームは、帯電器２により予め一様に帯電されている感光体上を走査する。レーザービーム３３の主走査と感光体の回転による副走査によりドラム表面に潜像が形成されていく。
また、感光体がベルト状のように平面状態をとる記録装置にあたっては、画像露光をフラッシュ露光とすることもできる。
【００８９】
【実施例】
以下、本発明を実施例及び製造例により、より詳細に説明するが、これらに限定されるものではない。
【００９０】
フタロシアニン顔料の製造法
〔製造例１〕
フタロジニトリル９７．５ｇをα−クロロナフタレン７５０ｍｌに加え、次に窒素雰囲気下で四塩化チタン２２ｍｌを滴下した。滴下後昇温し、攪拌しながら２００〜２２０℃で３時間反応させた後、放冷し、１００〜１３０℃で熱時ろ過し、１００℃に加熱したα−クロロナフタレン２００ｍｌで洗浄した。さらに２００ｍｌのＮ−メチルピロリドンで熱懸洗処理（１００℃、１時間）を３回行った。続いてメタノール３００ｍｌで室温にて懸洗しさらにメタノール５００ｍｌで１時間熱懸洗を３回行った。さらに得られたオキシチタニウムフタロシアニンをサンドグラインドミルにて２０時間磨砕処理を行い、続いて水４００ｍｌ、オルソジクロロベンゼン４０ｍｌの懸濁液中に入れ、６０℃で１時間加熱処理を行った。この様にして得られたオキシチタニウムフタロシアニンのＸ線回折スペクトルを図１に示す。図１から明らかなように、ブラッグ角（２θ±０．２°）で２７．３°に鋭いピークを示していることがわかる。
【００９１】
ビスアゾ顔料〔Ｉ〕の製造法（特開昭６３−１９５６５７号公報に準拠）
〔製造例２〕
２−ヒドロキシまたは５−ヒドロキシ−７Ｈ−ベンズイミダゾ〔２，１−ａ〕ベンゾ〔ｄｅ〕イソキノリン−７−オン（カップラーＮｏ．Ａ−１）２．４３部とナフトールＡＳ（カップラーＮｏ．Ｂ−１２）２．２４部をジメチルスルホキシド８２５部に溶解した。この溶液を２０〜２３℃の温度に保ちながら、２，５−ビス（ｐ−アミノフェニル）−１，３，４−オキサジアゾールをジアゾ化して得られたテトラゾニウムホウフッ化水素酸塩２．９２部をジメチルスルホキシド５５部に溶解した溶液を加えた後、攪拌しつつ、酢酸ナトリウム５部を水１５部に溶解した溶液を滴下し、そのまま３時間攪拌した。析出した沈殿を濾別し、ジメチルスルホキシド、希酢酸、水、メタノール、テトラヒドロフランで洗浄後、乾燥した。収量は１．７４部であった。
【００９２】
【化９】

【００９３】
〔実施例１〕
製造例１で製造したオキシチタニウムフタロシアニン２重量部、製造例２で製造したアゾ化合物８重量部にｎ−プロパノール２００重量部を加え、サンドグラインドミルで１０時間粉砕、微粒化分散処理を行った。次に、ポリビニルブチラール（電気化学工業（株）製、商品名デンカブチラール＃６０００Ｃ）５重量部の１０％メタノール溶液と混合して分散液を作成した。次に、この分散液をポリエステルフィルム上に蒸着したアルミニウム蒸着面の上にバーコータにより乾燥後の膜厚が０．４μｍとなるように電荷発生層を設けた。次に、この電荷発生層の上に、次に示すヒドラゾン化合物５６重量部と
【００９４】
【化１０】

【００９５】
及びポリカーボネート樹脂（三菱化成（株）製、商品名ノバレックス７０３０Ａ）１００重量部を１，４ジオキサン１０００重量部に溶解させた液をフィルムアプリケータにより塗布し、乾燥後の膜厚が１７μｍとなるように電荷移動層を設けた。この様にして得られた感光体を感光体Ａとする。
【００９６】
〔実施例２〕
実施例１において用いられたオキシチタニウムフタロシアニンとアゾ化合物〔Ｉ〕との混合比に代えて、製造例１で製造したオキシチタニウムフタロシアニン４重量部、製造例２で製造したアゾ化合物６重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を感光体Ｂとする。
【００９７】
〔実施例３〕
実施例１において用いられたオキシチタニウムフタロシアニンとアゾ化合物との混合比に代えて、製造例１で製造したオキシチタニウムフタロシアニン６重量部、製造例２で製造したアゾ化合物４重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を感光体Ｃとする。
【００９８】
〔実施例４〕
実施例１において用いられたオキシチタニウムフタロシアニンとアゾ化合物との混合比に代えて、製造例１で製造したオキシチタニウムフタロシアニン８重量部、製造例２で製造したアゾ化合物２重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を感光体Ｄとする。
【００９９】
〔比較例１〕
実施例１において用いられたオキシチタニウムフタロシアニンとアゾ化合物との混合に代えて、製造例１で製造したオキシチタニウムフタロシアニン１０重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を比較感光体Ｅとする。
【０１００】
〔比較例２〕
実施例１において用いられたアゾ化合物に代えて、下記の構造を有するアゾ化合物〔IV〕
【０１０１】
【化１１】

【０１０２】
を用いて、製造例１で製造したオキシチタニウムフタロシアニン２重量部、上記アゾ化合物〔IV〕８重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を比較感光体Ｆとする。
【０１０３】
〔比較例３〕
比較例２において用いられたオキシチタニウムフタロシアニンとアゾ化合物〔IV〕との混合比に代えて、製造例１で製造したオキシチタニウムフタロシアニン４重量部、アゾ化合物〔IV〕６重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を比較感光体Ｇとする。
【０１０４】
〔比較例４〕
比較例２において用いられたオキシチタニウムフタロシアニンとアゾ化合物〔IV〕との混合比に代えて、製造例１で製造したオキシチタニウムフタロシアニン６重量部、アゾ化合物〔IV〕４重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を比較感光体Ｈとする。
【０１０５】
〔比較例５〕
比較例２において用いられたオキシチタニウムフタロシアニンとアゾ化合物〔IV〕との混合比に代えて、製造例１で製造したオキシチタニウムフタロシアニン８重量部、アゾ化合物〔IV〕２重量部とした他は、実施例１と同様にして感光体を作成した。この様にして得られた感光体を比較感光体Ｉとする。
【０１０６】
〔実施例５〕
ポリエステルフィルム上に蒸着したアルミニウム蒸着面の上に、実施例１で設けた電荷移動層を乾燥後の膜厚が１５μｍとなるように設けた。実施例１において用いられたオキシチタニウムフタロシアニン５重量部、実施例１で用いられたアゾ化合物５重量部にメチルエチルケトン２００重量部を加え、サンドグインドミルで１０時間粉砕、微粒化分散処理を行った。次に、下記繰り返し単位構造を有する
【０１０７】
【化１２】

【０１０８】
ポリカーボネート樹脂１００重量部の１０％メチルエチルケトン溶液と混合して分散液を作成した。この分散液を先に設けた電荷輸送層の上にフィルムアプリケータにより塗布し、乾燥後の膜厚が５μｍとなるように電荷発生層を設けた。このようにして得られた感光体を感光体Ｊとする。
【０１０９】
〔評価〕
得られた感光体Ａ，Ｂ，Ｃ，Ｄ，Ｅ，Ｆ，Ｇ，Ｈ，ＩおよびＪは、初期電気特性として半減露光量感度を静電複写紙試験装置（川口電気製作所製、モデルＥＰＡ−８１００）により測定した。すなわち、暗所でコロナ放電により感光体を負帯電し、次いで７８０ｎｍ単色光を連続的に露光し、表面が−７００ｖから−３５０ｖに減少するのに要した露光量（Ｅ１／２）および残留電位（Ｖｒ）を測定した。その結果を表３に示す。
【０１１０】
ただし感光体Ｊは帯電極性を正帯電とした以外は同様に評価した。
さらに、感光体ＡおよびＦを感光体分光感度測定装置に装着し、分光感度を測定した。すなわち、暗所でコロナ放電により感光体を負帯電し、次いでモノクロメーターにて分光した単色光を連続的に露光し、表面が−７００ｖから−３５０ｖに減少するのに要した露光量（Ｅ１／２）を測定した。その結果は、測定露光量の逆数を感度とし、図４に示す。
【０１１１】
【表３２】

【０１１２】
表３より、感光体Ａ，Ｂ，ＣおよびＤは７８０ｎｍ単色光に対して高い感度を有し、かつ比較感光体Ｅ，Ｆ，Ｇ，ＨおよびＩより残留電位が低いことがわかる。また、感光体Ａ，Ｂ，ＣおよびＤを比較すると、フタロシアニンとビスアゾ顔料の混合比率を変化させることにより、幅広い範囲にわたり感度を自由にコントロールできることを示している。
【０１１３】
図４より、本発明に係るビスアゾ顔料とフタロシアニンを併用した感光体Ａは、ビスアゾ顔料〔IV〕とフタロシアニンを併用した比較感光体Ｆに比べ、可視光から近赤外領域に亘ってより高感度の分光感度特性を有していることがわかる。
【０１１４】
以上の結果から、本発明の感光体は、可視光から近赤外領域に亘って高感度の分光感度を有し、半導体レーザーを光源とするプリンタ機能と白色光を光源とする複写機能の両機能を兼ね備えた装置に適応可能な高感度、低残留電位の感光体を提供できる。
【図面の簡単な説明】
【図１】製造例１で得られたオキシチタニウムフタロシアニンのＸ線回折スペクトル図である。
【図２】本発明の感光体を用いる画像形成装置の一例の概念図である。
【図３】レーザービームスキャナーの作動説明図である。
【図４】本発明感光体の分光感度スペクトル図である。[0001]
[Industrial application fields]
The present invention relates to a photoreceptor, and more particularly to an electrophotographic photoreceptor.
[0002]
[Prior art]
Conventionally, photoconductors using inorganic photoconductive materials such as selenium, cadmium sulfide and zinc oxide have been used as electrophotographic photoconductors. However, recently, they are non-polluting and easy to manufacture and handle. So-called organic photoconductive substances (OPCs) that have many advantages such as good image quality, and the ability to easily obtain photoreceptors of various shapes such as drums, sheets, belts, etc. OPC photoconductors have been adopted for copying machines and printers, and the ratio has been increasing year by year.
[0003]
The first practical application as an OPC photoreceptor is sensitization by a charge transfer complex formed by mixing polyvinylcarbazole (PVK) and 2,4,7-trinitrofluorenone (TNF) which is an electron-withdrawing compound. The action was utilized. However, many charge transfer complex type OPC photoconductors have been developed since then, but those having performance exceeding that of the PVK-TNF photoconductors have not been put into practical use.
[0004]
Currently, a photoconductor called a function-separated type in which charge carrier generation and transfer functions are separated and assigned to different compounds is mainly put into practical use.
The functional separation type photoconductor can combine a compound with high charge carrier generation efficiency and a compound with high transfer efficiency, and also offers a wide range of choice of materials with excellent durability, high sensitivity and durability. This is a type capable of obtaining a photoconductor excellent in properties.
[0005]
Such electrophotographic photoreceptors are generally widely used in copying machines, printers and the like. For example, a photoconductor having photosensitivity with respect to a visible light source has been developed in a copying machine, while a printer using a semiconductor laser as a light source is used at the end of a computer. An electrophotographic photoreceptor incorporated in a printer must have high sensitivity in the near infrared region. In addition, development of an apparatus in which a copying function using white light as a light source is provided for a printer using a semiconductor laser is also in progress. In this case, the photoreceptor must first have high sensitivity in the near infrared region in order to adapt to the printer function, and also have high sensitivity in the visible light region in order to adapt to the copying function. That is, there is a demand for the development of a composite function electrophotographic photosensitive member that can be applied to an apparatus having both the printer function and the copying function using white light as a light source.
[0006]
At present, many bisazo pigments have been studied and put to practical use as known in JP-A Nos. 55-22834 and 56-111040 as carrier generating materials for copying machines. A photoreceptor containing such a bisazo pigment shows relatively good sensitivity in the short wavelength region to the medium wavelength region, but has low sensitivity in the long wavelength region and should be used for a printer using a semiconductor laser beam as a light source. I could not.
[0007]
On the other hand, a gallium-aluminum-arsenic (Ga-Al-As) light emitting element widely used as a light source for printers has an oscillation wavelength of 750 nm or more. Known carrier generating materials having sensitivity in such a long wavelength region include methacrylic squalic dyes, cyanine dyes, pyrylium dyes, thiapyrylium dyes, polyazo dyes, and phthalocyanine dyes. Of these, methacrylic squalic acid, cyanine dyes, pyrylium dyes, and thiapyrylium dyes are relatively easy to increase the spectral sensitivity, but lack practical stability for repeated use. It is difficult to increase the wavelength of absorption of the system dye, and there are difficulties in production. Phthalocyanine dyes can be synthesized relatively easily, have an absorption peak in the wavelength region of 600 nm or more, and have a longer absorption wavelength than other dyes, so that for long wavelength light sources Expected as a charge generating agent and has been widely studied. Phthalocyanines not only have different absorption spectra and photoconductivity depending on the type of central metal, but also have different physical properties depending on the crystal type. Several examples have been reported that have been selected for the photoreceptor. For example, oxytitanium phthalocyanine has various crystal types, and it has been reported that there are large differences in chargeability, dark decay, sensitivity, and the like due to differences in the crystal types. In Japanese Patent Application Laid-Open No. 59-49544, the crystal type of oxytitanium phthalocyanine includes Bragg angles (2θ ± 0.2 °) = 9.2 °, 13.1 °, 20.7 °, 26.2 °, What gives a strong diffraction peak at 27.1 ° is described as being suitable, and an X-ray diffraction spectrum diagram is shown. In JP-A-59-166959, a vapor-deposited film of oxytitanium phthalocyanine is left in a saturated vapor of tetrahydrofuran for 1 to 24 hours to change the crystal form to form a carrier generation layer. The X-ray diffraction spectrum has a small number of peaks and a wide width, and the Bragg angle (2θ) = 7.5 °, 12.6 °, 13.0 °, 25.4 °, 26.2 °, 28. It is shown to show a strong diffraction peak at 6 °. Furthermore, in Japanese Patent Application Laid-Open No. 64-17066, the main peak of Bragg angle (2θ ± 0.2 °) is at least 9.5 °, 9.7 °, 11.7 °, 15 ° as the crystal form of oxytitanium phthalocyanine. , 23.5 °, 24.1 ° and 27.3 ° are preferred.
[0008]
However, such an electrophotographic photosensitive member having sensitivity in the long wavelength range has insufficient photosensitivity from the middle wavelength range to the short wavelength range and cannot be applied to a copying function using a white light source or the like.
[0009]
[Problems to be solved by the invention]
As described above, the electrophotographic photosensitive member for visible light and the electrophotographic photosensitive member for semiconductor laser each have relatively good characteristics. However, the photosensitive member has a wide sensitivity from a short wavelength region to a long wavelength region. The body is sought. Furthermore, as the speed of electrophotographic copying machines and printers and the diameter of photosensitive drums have decreased, the time required for the copying process has been significantly shortened, digitization has progressed, and the number of copies has increased, further increasing the number of copies. High sensitivity, stabilization of charging characteristics, high responsiveness of light attenuation, physical and chemical durability, and so on.
[0010]
As such a photoreceptor having a panchromatic and adjustable sensitivity, for example, JP-A 63-236048 discloses a photoreceptor containing both N-methyldiphenylamine type and anthraquinone type bisazo pigments. Japanese Laid-Open Patent Publication No. 63-236049 proposes a photoconductor including a phenanthraquinone type in place of the anthraquinone type in the above photoconductor, but these photoconductors have a light sensitivity in a long wavelength region. It was inadequate and not really satisfactory.
[0011]
JP-A-3-37667 discloses a photoreceptor containing both titanyl phthalocyanine and a bisazo pigment having a specific structure. Although this photoreceptor is panchromatic, it has an overall sensitivity. However, the above-mentioned requirements for high sensitivity and high response were not satisfied.
In particular, in an electrophotographic photosensitive member using a semiconductor laser as a light source, the sensitivity of the photosensitive member is uniquely determined by the photoconductive material used. It does not always match the required light sensitivity, and may cause problems such as thickening and thinning of characters and resolution, and places restrictions on the construction of an image forming process for obtaining high-quality images.
[0012]
As a method for adjusting the photosensitivity of the electrophotographic photosensitive member to the photosensitivity required by the exposure light source, an example using a mixture of a plurality of phthalocyanines has been reported. For example, in Japanese Patent Laid-Open No. 62-272272, α-type oxytitanium phthalocyanine and β-type oxytitanium phthalocyanine, or in Japanese Patent Laid-Open No. 2-183261, Bragg angles (2θ) = 9.6 °, 11.7 °, 24.1. Oxytitanium phthalocyanine having a crystal type giving peaks at °, 27.2 ° and oxytitanium phthalocyanine having crystal types giving peaks at 6.9 °, 15.5 ° and 23.4 ° A method of adjusting sensitivity by mixing oxytitanium phthalocyanine and changing the mixing ratio thereof, and JP-A-2-280169 discloses mixing oxytitanium phthalocyanine with other types of phthalocyanines such as metal-free phthalocyanine, copper phthalocyanine, etc. How to adjust is shown.
[0013]
However, the photoconductors shown in these examples have a narrow sensitivity adjustment range, so that the photosensitivity can only be adjusted to the photosensitivity of a specific exposure light source, the potential fluctuation is large when used repeatedly, or the characteristics vary depending on the environment. There was a problem such as a large change, and in fact it was not satisfactory.
[0014]
OBJECT OF THE INVENTION
An object of the present invention is an apparatus having a high spectral sensitivity from visible light to the near infrared region, and having both a printer function using a semiconductor laser as a light source and a copying function using white light as a light source. It is an object of the present invention to provide a high-performance electrophotographic photosensitive member that can be adapted and that the sensitivity of the electrophotographic photosensitive member can be matched to the light amount of the semiconductor laser exposure beam used here so that the image quality is sharp.
[0015]
[Means for Solving the Problems]
The above-described object of the present invention is achieved by including oxytitanium phthalocyanine and a bisazo pigment represented by the general formula [I] in the photosensitive layer of the electrophotographic photoreceptor.
The present invention will be described in detail below.
Examples of the oxytitanium phthalocyanine used in the present invention include the following general formula [Pc]
[0016]
[Chemical Formula 3]

[0017]
(In the formula, X represents a halogen atom, and n represents a number from 0 to 1.)
The thing shown by is mentioned.
In the general formula [Pc], X is preferably a chlorine atom and n is from 0 to 0.5. The oxytitanium phthalocyanine used in the present invention is easily synthesized from a conventionally known method, for example, 1,2-dicyanobenzene (orthophthalodinitrile) and a titanium compound according to the reaction formula shown in the following (1) or (2). can do.
[0018]
[Formula 4]

[0019]
That is, 1,2-dicyanobenzene and a halide of titanium are heated and reacted in an inert solvent. As the titanium compound, titanium tetrachloride, titanium trichloride, titanium tetrabromide, or the like can be used. Reactions such as trichlorobenzene, α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenyl ether, diphenylmethane, diphenylethane, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether as inert solvents Highly boiling organic solvents which are inert to water are preferred. The reaction temperature is usually 150 to 300 ° C, particularly preferably 180 to 250 ° C. The dichlorotitanium phthalocyanine produced after the reaction is filtered off and washed with the solvent used for the reaction to remove impurities produced during the reaction and unreacted raw materials.
[0020]
Next, the solvent used in the reaction is removed by washing with an inert solvent such as alcohols such as methanol, ethanol and isopropyl alcohol, and ethers such as tetrahydrofuran and diethyl ether. Subsequently, the obtained dichlorotitanium phthalocyanine is hydrolyzed to become oxytitanium phthalocyanine.
[0021]
Subsequently, the obtained oxytitanium phthalocyanine is subjected to, for example, hydrothermal treatment disclosed in JP-A-62-67094 or mechanical grinding treatment disclosed in JP-A-2-215866 to obtain a target crystal form. be able to. Further, the crystalline oxytitanium phthalocyanine used in the present invention is not limited to the crystalline oxytitanium phthalocyanine produced by the above production method. For example, the crystalline oxytitanium phthalocyanine is also suitable from other crystalline oxytitanium phthalocyanines. It may be oxytitanium phthalocyanine that can be produced by any treatment and produced by any production method. In particular, in its X-ray diffraction spectrum, the Bragg angle (2θ ± 0.2 °) is clearly 27.3 °. 1 which belongs to the same crystal form as the crystal form of which the X-ray diffraction spectrum is shown in FIG. 1 (however, it is usually other than 27.3 °, around 29.5 ° at 9.5 °). Shows a relatively clear diffraction peak (hereinafter referred to as phthalocyanine).
[0022]
In the bisazo pigment represented by the following general formula [I] according to the present invention,
Formula [I]
[0023]
[Chemical formula 5]

[0024]
A represents a residue of a coupler represented by the following general formula [II], and B represents a residue of a coupler having a phenolic hydroxyl group different from A.
General formula [II]
[0025]
[Chemical 6]

[0026]
In the formula [II], Q represents an aromatic hydrocarbon divalent group which may have a substituent, or a heterocyclic divalent group which may have a substituent.
The azo compound will be described in detail. In the above general formula [I], A and B bonded to the azo group represent different coupler residues. A represents a coupler residue in which a coupler of the general formula [II] is bonded to a diazonium salt by a coupling reaction. In the general formula [II], Q is a divalent aromatic hydrocarbon which may have a substituent. Or a divalent group of a heterocyclic ring which may have a substituent. Examples of the aromatic hydrocarbon divalent group include monovalent aromatic hydrocarbon divalent groups such as an o-phenylene group, o-naphthylene group, 1,8-naphthylene group, and 1,2-anthra. And divalent groups of condensed polycyclic aromatic hydrocarbons such as a quinonylene group and a 9,10-phenanthrylene group.
[0027]
Examples of the divalent group of the heterocyclic ring include 3,4-pyrazolediyl group, 2,3-pyridinediyl group, 3,4-pyridinediyl group, 4,5-pyrimidinediyl group, 6,7- Examples thereof include a divalent group of a heterocyclic ring such as an indazolediyl group, a 5,6-benzimidazolediyl group, and a 5,6-quinolinediyl group.
[0028]
These divalent groups of aromatic hydrocarbons and divalent groups of the heterocyclic ring may have a substituent. For example, alkyl group such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, hexyl group; trifluoromethyl group; methoxy group, ethoxy group, propoxy group, butoxy Hydroxyl groups; nitro groups; cyano groups; amino groups; substituted amino groups such as dimethylamino groups, diethylamino groups, and dibenzylamino groups; halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms Carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; carbamoyl group; acyl group such as acetyl group and benzoyl group; aryloxy group such as phenoxy group; arylalkoxy group such as benzyloxy group; aryloxy group such as phenoxycarbonyl group; A carbonyl group etc. are mentioned. Of these, alkyl groups, alkoxy groups, nitro groups, halogen atoms, hydroxyl groups, carbamoyl groups, particularly methyl groups, methoxy groups, nitro groups, chlorine atoms, and hydroxyl groups are preferred.
[0029]
B represents a residue of a coupler having a phenolic hydroxyl group different from A, and any coupler that undergoes a coupling reaction with a diazonium salt can be used.
The phenolic hydroxyl group is a hydroxyl group substituted with an aromatic hydrocarbon ring, and a hydrocarbon ring or a heterocyclic ring may be further condensed to the aromatic hydrocarbon ring.
[0030]
As B, a coupler of the general formula [II] different from A can be used, but a coupler residue represented by the following general formula [III] is particularly preferable.
General formula [III]
[0031]
[Chemical 7]

[0032]
(In the above formula, R₁And R₂Each independently represents a hydrogen atom, a lower alkyl group which may have a substituent, an aryl group or a heterocyclic group;₁And R₂May be bonded to each other to form a ring. Z represents a divalent group necessary for condensing with a benzene ring to form an aromatic hydrocarbon ring or a heterocyclic ring. )
Some examples of the substituent in the above general formula [III] are as follows. Examples of the lower alkyl group which may have a substituent include methyl, ethyl, n-propyl, n-butyl, i- Examples thereof include a butyl group, a tert-butyl group, and a hexyl group. Examples of the aryl group include an aromatic hydrocarbon group such as a phenyl group, a phenanthryl group, an anthraquinolyl group, an acenaphthyl group, a fluorenyl group, a biphenylyl group, a p-terphenylyl group, and a p-styrylphenyl group. Alkyl groups such as methyl, ethyl, and butyl; halogen atoms such as fluorine, chlorine, bromine, and iodine; alkoxy groups such as methoxy, ethoxy, and butoxy; aryloxy groups such as phenoxy; hydroxy groups; nitro Group; cyano group; amino group; substituted amino group such as dimethylamino group, diethylamino group, dibenzylamino group; carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; aryloxycarbonyl group such as phenyloxycarbonyl group; acetoxy group , Acylo such as benzoyloxy group Shi group; an acetyl group, an acyl group such as benzoyl group; a carbamoyl group, a dimethylaminocarbonyl group, a substituted amino group such as a phenylaminocarbonyl group; a benzyloxy group, an aryl alkoxy group such as a phenethyloxy group.
[0033]
Heterocyclic groups include furyl, thienyl, thiazolyl, indolyl, pyrrolyl, carbazolyl, pyridyl, morpholino, quinolyl, imidazolyl, oxazolyl, triazolyl, piperidyl, benzoxazolyl Benzoimidazolyl group, benzothiazolyl group, acridyl group, xanthenyl group, phenazinyl group, phenothiazinyl group, coumarinyl group and the like, and may have the same substituent as the aryl group.
[0034]
Examples of Z include a divalent group necessary for condensing with a benzene ring to form an aromatic hydrocarbon or a heterocyclic ring such as a naphthalene ring, an anthracene ring, a carbazole ring, a benzocarbazole ring, and a dibenzofuran ring.
R₁And R₂However, examples of the group that is bonded to each other to form a ring include a cyclohexylidene group, an indenylidene group, a fluoronylidene group, and a pentamethylene group.
[0035]
Some specific examples of the structural formulas of the couplers represented by the general formulas [II] and [III] are shown in Tables 1 and 2 below. Of course, the present invention is not limited to these specific examples.
[0036]
[Table 1]

[0037]
[Table 2]

[0038]
[Table 3]

[0039]
[Table 4]

[0040]
These couplers have two types of isomers as seen in A-1 and A-2, but for the sake of clarity, only examples of one of these isomers are shown in A-3 and later.
[0041]
[Table 5]

[0042]
[Table 6]

[0043]
[Table 7]

[0044]
[Table 8]

[0045]
[Table 9]

[0046]
[Table 10]

[0047]
[Table 11]

[0048]
[Table 12]

[0049]
[Table 13]

[0050]
[Table 14]

[0051]
[Table 15]

[0052]
[Table 16]

[0053]
[Table 17]

[0054]
[Table 18]

[0055]
[Table 19]

[0056]
[Table 20]

[0057]
[Table 21]

[0058]
[Table 22]

[0059]
[Table 23]

[0060]
[Table 24]

[0061]
[Table 25]

[0062]
[Table 26]

[0063]
[Table 27]

[0064]
[Table 28]

[0065]
[Table 29]

[0066]
[Table 30]

[0067]
[Table 31]

[0068]
The bisazo pigment according to the present invention can be produced, for example, in accordance with Production Examples 1, 2, and 3 in JP-A No. 63-195657.
[0069]
[Chemical 8]

[0070]
The bisazo pigment general formula [I] according to the present invention has high sensitivity in the region of 450 nm to 600 nm and supplements the sensitivity of the low sensitivity spectral region of the phthalocyanine used in the present invention, and is used in combination with the phthalocyanine pigment according to the present invention. Thus, it has a wide sensitivity from a short wavelength region to a long wavelength region, and has a feature that the sensitivity can be easily adjusted by changing the mixing ratio of the bisazo pigment and phthalocyanine.
[0071]
Such a combination of different kinds of carrier generating substances does not necessarily have a uniform selection means, and in the present invention, the combination of the phthalocyanine pigment and the bisazo pigment was determined by accumulating experiments among many compounds. Is.
[0072]
The photoconductor of the present invention is suitable as a copying machine (for example, an image signal such as a fluorescent lamp, a halogen lamp, or a xenon lamp) that requires a main spectral sensitivity in the visible range, and has a long wavelength in the visible range. It is also suitable as a printer that requires spectral sensitivity in the side or near infrared region (for example, a gas laser such as a light emitting diode or a He-Ne laser, or an image signal such as a semiconductor laser, that is, a digital signal). In this sense, both analog and digital systems can be realized.
[0073]
Next, as a method for producing a coating solution for coating the photosensitive layer, (1) When phthalocyanine and bisazo pigment are used in different photosensitive layers, phthalocyanine and bisazo pigment are dispersed in different dispersion media. In addition, it is adjusted to the state of being mixed with the binder resin, and each coating method is used. (2) When using phthalocyanine and bisazo pigment in the same layer, these phthalocyanine and bisazo pigment are mixed and dispersed in a dispersion medium. Finally, it is prepared as a coating solution for coating the photosensitive layer in a state where it is mixed with the binder resin, or phthalocyanine and bisazo pigment are each dispersed in a dispersion medium and further mixed with the binder resin. The prepared solution is used as a coating solution, or each adjusted solution is mixed to obtain a coating solution.
[0074]
Various solvents may be used as the dispersion medium. For example, ethers such as diethyl ether, dimethoxymethane, tetrahydrofuran and 1,2-dimethoxyethane; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; alcohols such as methanol, ethanol and propanol alone Alternatively, two or more kinds can be mixed and used.
[0075]
As binder resins, polyvinyl butyral, polyvinyl acetal, polyester, polycarbonate, polystyrene, polyester carbonate, polysulfone, polyimide, polymethyl methacrylate, polyvinyl chloride and other vinyl polymers, and copolymers thereof, phenoxy, epoxy, silicone resin, etc. These partially cross-linked cured products can be used alone or in combination of two or more.
[0076]
As a method for dispersing the phthalocyanine and the bisazo pigment, a known method such as a ball mill, a sand grind mill, a planetary mill, or a roll mill can be used.
Examples of the method of mixing the binder resin with the phthalocyanine and / or bisazo pigment particles include, for example, a method in which the binder resin is in powder form or the polymer solution is added and dispersed simultaneously during the dispersion treatment of the phthalocyanine and bisazo pigment particles. Any method may be used, such as a method of mixing the polymer solution into the binder resin polymer solution, or a method of mixing the polymer solution into the dispersion.
[0077]
In the case of using a mixture of phthalocyanine and bisazo pigment, the content ratio of phthalocyanine is usually 0.05 parts by weight to 10 parts by weight with respect to 1 part by weight of phthalocyanine. When the phthalocyanine and bisazo pigments are separately dispersed in a dispersion medium, adjusted to a state where they are mixed with a binder resin, and each adjusted solution is mixed to form a coating solution for coating a photosensitive layer As for the mixing method of each of the prepared liquids, any known method such as mixing using a mechanical stirrer, homomixer, homogenizer or the like, or mixing by applying ultrasonic waves may be used.
[0078]
Next, the dispersion obtained here may be diluted with various solvents in order to obtain liquid properties suitable for coating. As this solvent, for example, the solvent exemplified as the dispersion medium can be used. The ratio of the phthalocyanine and / or bisazo pigment to the binder resin is not particularly limited, but generally the total amount of phthalocyanine and / or bisazo pigment is used in the range of 5 to 500 parts by weight with respect to 100 parts by weight of the resin. . In this dispersion, the concentration of the phthalocyanine and / or bisazo pigment is preferably used in the range of 0.1% by weight to 10% by weight.
[0079]
Moreover, a charge transfer agent can be included as needed. Examples of the charge transfer agent include electron-withdrawing substances such as 2,4,7-trinitrofluorenone and tetracyanoxydimethane, heterocyclic compounds such as carbazole, indole, imidazole, oxazole, oxadiazole, pyrazoline and thiazole, Examples thereof include electron donating substances such as aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, or polymers having groups composed of these compounds in the main chain or side chain. The ratio of the charge transfer agent to the binder resin is used in the range of 5 to 500 parts by weight of the charge transfer agent with respect to 100 parts by weight of the binder resin.
[0080]
In the case of using a mixture of phthalocyanine and bisazo pigment, a charge generation layer is formed on a conductive support using the mixed dispersion prepared in this manner, and a charge transfer layer is laminated thereon. A photosensitive layer is formed, or a charge transfer layer is formed on a conductive support and a charge generation layer is formed thereon using the mixed dispersion to form a photosensitive layer, or on a conductive support. The photosensitive layer can be formed with any structure in which a charge generation layer is formed using the mixed dispersion to form a photosensitive layer. When the phthalocyanine and the bisazo pigment are used in separate layers, a first charge generation layer is formed on the conductive support, a second charge generation layer is formed thereon, and a charge transfer layer is further formed thereon. Or a photosensitive layer in which a charge transfer layer is formed on a conductive support, a second charge generation layer is formed thereon, and a first charge generation layer is further stacked thereon. Either a layer or a photosensitive layer in which a first charge generation layer is formed on a conductive support and a second charge generation layer is laminated thereon can be employed. The phthalocyanine or bisazo pigment may be used in either the first charge generation layer or the second charge generation layer. When the charge generation layer is laminated with the charge transfer layer to form a photosensitive layer, the range of 0.1 μm to 10 μm is suitable, and the thickness of the charge transfer layer is preferably 5 μm to 60 μm. The film thickness of the photosensitive layer in the case where the photosensitive layer is formed of a single structure having only the charge generation layer or two charge generation layers is preferably in the range of 5 μm to 60 μm.
[0081]
When the charge transfer layer is provided, as the charge transfer agent used there, the materials exemplified as the charge transfer agent can be used. If necessary, a binder resin is blended with these charge transfer agents. As the binder resin, for example, those exemplified as the binder resin can be used. The photosensitive layer may contain various additives such as an antioxidant and a sensitizer as necessary.
[0082]
The photosensitive layer is provided on a conductive support, but the conductive support can be selected from known materials such as aluminum, stainless steel, nickel, and the like, and aluminum, copper, palladium, tin oxide, oxide on the surface. An insulating support such as a polyester film provided with a conductive layer such as indium, paper, or glass is used.
[0083]
A well-known barrier layer as commonly used may be provided between the conductive support and the photosensitive layer. Examples of the barrier layer include inorganic layers such as aluminum anodized film, aluminum oxide and aluminum hydroxide, organic materials such as polyvinyl alcohol, casein, polyvinyl pyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide and polyamide. Layers are used. The thickness of the barrier layer is preferably in the range of 0.1 μm to 20 μm, and most effectively used in the range of 0.1 μm to 10 μm.
[0084]
Next, an example of an image forming apparatus using the photoreceptor 1 of the present invention is shown in FIG. Here, 2 is a band electrode, 3 is a light source for long wavelength light, 4 is a light source for short wavelength light (visible light), 5 is a developing device, 7 is a transfer electrode, 8 is a separation electrode, 9 is a cleaning blade, and 10 is a charge removal It is a lamp.
Examples of light sources that can be used for the light sources 3 and 4 include white light, halogen lamp light, tungsten lamp light, fluorescent lamp light, and laser light (semiconductor laser, He—Ne laser) LED.
[0085]
The developing device 5 may be either a normal forward developing method or a reversal developing method. The static elimination lamp 10 is effective in both forward development and reverse development.
When an image is formed, when a white light source is used, the photoconductor charged with 2 is exposed with image 4 and developed with 5. This is transferred to the transfer paper 6 by the transfer electrode 7 and the transfer paper is separated by the separation electrode 8. The toner remaining on the photoreceptor 1 is scraped off by 9 and cleaned.
[0086]
On the other hand, when a laser light source is used, the photoreceptor charged with 2 is image-exposed with 3 and developed with 5. This is transferred to the transfer paper 6 by the transfer electrode 7 and the transfer paper is separated by the separation electrode 8. The toner remaining on the photoreceptor 1 is scraped off by 9 and cleaned.
As for the image forming apparatus using a drum-shaped photoconductor, image exposure using a laser light source is preferably performed using a laser beam scanner as shown in FIG.
[0087]
Next, the operation of the laser beam scanner of FIG. 3 will be described.
The laser beam generated by the semiconductor laser 21 is swung left and right within a predetermined amplitude angle by a polygon mirror 23 rotated by a drive motor 22, and the optical path is bent by a reflecting mirror 25 through an f-θ lens 24. Is projected onto the surface of the line 26 and scans over the line 26.
[0088]
Reference numeral 27 denotes an index sensor for detecting the start of beam scanning, and 28 and 29 denote tilting angle correcting cylindrical lenses. Reference numerals 30, 31, and 32 denote reflecting mirrors that form a beam scanning optical path and a beam detecting optical path.
When scanning is started, the beam is detected by the index sensor 27, and modulation of the beam by the signal is started by a modulation unit (not shown). The modulated beam scans the photosensitive member that is uniformly charged in advance by the charger 2. A latent image is formed on the drum surface by the main scanning of the laser beam 33 and the sub scanning by the rotation of the photosensitive member.
In a recording apparatus in which the photoconductor is in a flat state like a belt, the image exposure can be flash exposure.
[0089]
【Example】
EXAMPLES Hereinafter, although an Example and a manufacture example demonstrate this invention in detail, it is not limited to these.
[0090]
Method for producing phthalocyanine pigments
[Production Example 1]
97.5 g of phthalodinitrile was added to 750 ml of α-chloronaphthalene, and then 22 ml of titanium tetrachloride was added dropwise under a nitrogen atmosphere. After dropping, the temperature was raised and the mixture was allowed to react at 200 to 220 ° C. for 3 hours with stirring, then allowed to cool, filtered hot at 100 to 130 ° C., and washed with 200 ml of α-chloronaphthalene heated to 100 ° C. Further, a hot washing treatment (100 ° C., 1 hour) was performed 3 times with 200 ml of N-methylpyrrolidone. Subsequently, the suspension was washed with 300 ml of methanol at room temperature, and further washed with 500 ml of methanol for 1 hour. Further, the obtained oxytitanium phthalocyanine was ground in a sand grind mill for 20 hours, then placed in a suspension of 400 ml of water and 40 ml of orthodichlorobenzene, and heat-treated at 60 ° C. for 1 hour. The X-ray diffraction spectrum of the oxytitanium phthalocyanine thus obtained is shown in FIG. As can be seen from FIG. 1, a sharp peak at 27.3 ° is shown at the Bragg angle (2θ ± 0.2 °).
[0091]
Process for producing bisazo pigment [I](Conforms to JP-A 63-195657)
[Production Example 2]
2-hydroxy or 5-hydroxy-7H-benzimidazo [2,1-a] benzo [de] isoquinolin-7-one (coupler No. A-1) 2.43 parts and naphthol AS (coupler No. B-12) ) 2.24 parts were dissolved in 825 parts of dimethyl sulfoxide. Tetrazonium borofluoride 2 obtained by diazotizing 2,5-bis (p-aminophenyl) -1,3,4-oxadiazole while keeping this solution at a temperature of 20 to 23 ° C. After adding a solution of .92 parts dissolved in 55 parts of dimethyl sulfoxide, a solution prepared by dissolving 5 parts of sodium acetate in 15 parts of water was added dropwise and stirred for 3 hours. The deposited precipitate was separated by filtration, washed with dimethyl sulfoxide, dilute acetic acid, water, methanol, and tetrahydrofuran, and then dried. The yield was 1.74 parts.
[0092]
[Chemical 9]

[0093]
[Example 1]
200 parts by weight of n-propanol was added to 2 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 8 parts by weight of the azo compound produced in Production Example 2, followed by pulverization and atomization dispersion treatment for 10 hours in a sand grind mill. Next, polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name Denkabutyral # 6000C) was mixed with 5 parts by weight of a 10% methanol solution to prepare a dispersion. Next, a charge generation layer was provided on the aluminum deposition surface on which the dispersion was deposited on a polyester film so that the thickness after drying by a bar coater was 0.4 μm. Next, on this charge generation layer, 56 parts by weight of the following hydrazone compound and
[0094]
[Chemical Formula 10]

[0095]
And a solution obtained by dissolving 100 parts by weight of polycarbonate resin (product name: Novalex 7030A, manufactured by Mitsubishi Kasei Co., Ltd.) in 1,000 parts by weight of 1,4 dioxane is applied by a film applicator, and the film thickness after drying becomes 17 μm. Thus, a charge transfer layer was provided. The photoreceptor thus obtained is referred to as a photoreceptor A.
[0096]
[Example 2]
Instead of the mixing ratio of oxytitanium phthalocyanine and azo compound [I] used in Example 1, 4 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 6 parts by weight of azo compound produced in Production Example 2 were used. Otherwise, a photoconductor was prepared in the same manner as in Example 1. The photoreceptor thus obtained is referred to as a photoreceptor B.
[0097]
Example 3
Instead of the mixing ratio of oxytitanium phthalocyanine and azo compound used in Example 1, 6 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 4 parts by weight of azo compound produced in Production Example 2, A photoconductor was prepared in the same manner as in Example 1. The photoreceptor thus obtained is designated as photoreceptor C.
[0098]
Example 4
Instead of the mixing ratio of oxytitanium phthalocyanine and azo compound used in Example 1, 8 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 2 parts by weight of azo compound produced in Production Example 2, A photoconductor was prepared in the same manner as in Example 1. The photoreceptor thus obtained is designated as photoreceptor D.
[0099]
[Comparative Example 1]
A photoconductor was prepared in the same manner as in Example 1 except that 10 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 was used instead of the mixture of oxytitanium phthalocyanine and azo compound used in Example 1. The photoreceptor thus obtained is referred to as a comparative photoreceptor E.
[0100]
[Comparative Example 2]
Instead of the azo compound used in Example 1, an azo compound [IV] having the following structure:
[0101]
Embedded image

[0102]
Was used in the same manner as in Example 1 except that 2 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 8 parts by weight of the azo compound [IV] were used. The photoreceptor thus obtained is referred to as a comparative photoreceptor F.
[0103]
[Comparative Example 3]
Instead of the mixing ratio of oxytitanium phthalocyanine and azo compound [IV] used in Comparative Example 2, 4 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 6 parts by weight of azo compound [IV] were used. A photoconductor was prepared in the same manner as in Example 1. The photoreceptor thus obtained is referred to as a comparative photoreceptor G.
[0104]
[Comparative Example 4]
Instead of the mixing ratio of oxytitanium phthalocyanine and azo compound [IV] used in Comparative Example 2, except that 6 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 4 parts by weight of azo compound [IV] were used, A photoconductor was prepared in the same manner as in Example 1. The photoreceptor thus obtained is referred to as a comparative photoreceptor H.
[0105]
[Comparative Example 5]
Instead of the mixing ratio of oxytitanium phthalocyanine and azo compound [IV] used in Comparative Example 2, 8 parts by weight of oxytitanium phthalocyanine produced in Production Example 1 and 2 parts by weight of azo compound [IV] were used. A photoconductor was prepared in the same manner as in Example 1. The photoreceptor thus obtained is referred to as a comparative photoreceptor I.
[0106]
Example 5
On the aluminum vapor deposition surface vapor-deposited on the polyester film, the charge transfer layer provided in Example 1 was provided so that the film thickness after drying was 15 μm. 200 parts by weight of methyl ethyl ketone was added to 5 parts by weight of oxytitanium phthalocyanine used in Example 1 and 5 parts by weight of the azo compound used in Example 1, and the mixture was pulverized with a sand grind mill for 10 hours and subjected to atomization dispersion treatment. Next, it has the following repeating unit structure
[0107]
Embedded image

[0108]
A dispersion was prepared by mixing with 100 parts by weight of a polycarbonate resin with a 10% methyl ethyl ketone solution. This dispersion was applied onto the charge transport layer previously provided by a film applicator, and a charge generation layer was provided so that the film thickness after drying was 5 μm. The photoreceptor thus obtained is designated as photoreceptor J.
[0109]
[Evaluation]
The obtained photoreceptors A, B, C, D, E, F, G, H, I and J have an electrostatic copy paper test apparatus (model EPA-, manufactured by Kawaguchi Electric Co., Ltd.) as an initial electrical characteristic. 8100). That is, the photosensitive member is negatively charged by corona discharge in a dark place, then continuously exposed to 780 nm monochromatic light, and the exposure amount (E1 / 2) and residual potential required to reduce the surface from -700v to -350v. (Vr) was measured. The results are shown in Table 3.
[0110]
However, the photoconductor J was evaluated in the same manner except that the charging polarity was positively charged.
Further, the photoconductors A and F were mounted on a photoconductor spectral sensitivity measuring apparatus, and the spectral sensitivity was measured. That is, the exposure amount (E1 / E1) required for negatively charging the photoconductor by corona discharge in the dark and then continuously exposing monochromatic light dispersed by a monochromator to reduce the surface from -700v to -350v. 2) was measured. The result is shown in FIG. 4 with sensitivity as the reciprocal of the measured exposure dose.
[0111]
[Table 32]

[0112]
From Table 3, it can be seen that the photoreceptors A, B, C, and D have high sensitivity to 780 nm monochromatic light, and the residual potential is lower than that of the comparative photoreceptors E, F, G, H, and I. Further, comparing the photoreceptors A, B, C and D shows that the sensitivity can be freely controlled over a wide range by changing the mixing ratio of the phthalocyanine and the bisazo pigment.
[0113]
As shown in FIG. 4, the photoreceptor A using the bisazo pigment and phthalocyanine according to the present invention has higher sensitivity from the visible light to the near infrared region than the comparative photoreceptor F using the bisazo pigment [IV] and phthalocyanine together. It can be seen that it has the following spectral sensitivity characteristics.
[0114]
From the above results, the photoreceptor of the present invention has a high spectral sensitivity from visible light to the near infrared region, and both a printer function using a semiconductor laser as a light source and a copying function using white light as a light source. It is possible to provide a high-sensitivity and low-residual-potential photoconductor that can be applied to an apparatus having functions.
[Brief description of the drawings]
1 is an X-ray diffraction spectrum diagram of oxytitanium phthalocyanine obtained in Production Example 1. FIG.
FIG. 2 is a conceptual diagram of an example of an image forming apparatus using the photoconductor of the present invention.
FIG. 3 is an operation explanatory diagram of a laser beam scanner.
FIG. 4 is a spectral sensitivity spectrum diagram of the photoconductor of the present invention.

Claims (2)

In an electrophotographic photoreceptor in which a photosensitive layer containing at least a carrier generating substance and a carrier transporting substance is provided on a conductive substrate, the photosensitive layer comprises oxytitanium phthalocyanine and a bisazo pigment represented by the following general formula [I]: An electrophotographic photosensitive member comprising:

[In the above formula [I], A represents a residue of a coupler represented by the following general formula [II], and B represents a residue of a coupler having a phenolic hydroxyl group different from A.

[In the above formula [II], Q represents a divalent residue of an aromatic hydrocarbon which may have a substituent, or a divalent group of a heterocyclic ring which may have a substituent. . )] 2. The electron according to claim 1, wherein the oxytitanium phthalocyanine is an oxytitanium phthalocyanine having a crystal form that gives a clear diffraction peak at 27.3 ° with a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum. Photoconductor for photography.

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