JP3582228B2 - Electrophotographic photoreceptor - Google Patents

Description

【０００８】
（上記式中で、Ｘは、ハロゲン原子を示す。また、Ｒ_１ およびＲ_２ は、それぞれ、独立に、水素原子または１〜４個の炭素原子を有するアルキル基を示し、Ｒ_３ およびＲ_４ は、水素原子、ハロゲン原子、または置換もしくは非置換のアミノ基を示す。）
【０００９】
【発明の実施の形態】
以下本発明を詳細に説明する。
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としては、例えば下記一般式［ＩＩ］
【００１０】
【化３】

【００１１】
（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［ＩＩ］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。
本発明に用いる結晶型オキシチタニウムフタロシアニンの合成法は特に限定されず、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例えば下記（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。
【００１２】
【化４】

【００１３】
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１３０〜３００℃、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。
【００１４】
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。得られたジクロロチタニウムフタロシアニンを有機溶剤処理、加水分解処理等によりオキシチタニウムフタロシアニンを得る。
例えば、特開平２−３０８８６３号、特開平３−５０２７０号、特開平３−５９０７７号各公報で開示している有機溶剤処理により、ジクロロチタニウムフタロシアニンから直接目的の結晶型のオキシチタニウムフタロシアニンを得ることができる。また、加水分解処理により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号で開示している熱水処理や特開平２−２１５８６６号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。
【００１５】
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結晶型オキシチタニウムフタロシアニンであっても、本発明における結晶型オキシチタニウムフタロシアニンとして使用することができる。
【００１６】
本発明に係る前記一般式［Ｉ］で示されるカチオン塩化合物において、Ｘは、フッ素原子、塩素原子等のハロゲン原子を示す。また、Ｒ_１ およびＲ_２ は、それぞれ、独立に、水素原子またはメチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｔ−ブチル基等の１〜４個の炭素原子を有するアルキル基を示し、Ｒ_３ およびＲ_４ は、それぞれ、独立に、水素原子、フッ素原子、塩素原子等のハロゲン原子、アルキルアミノ基、ジアルキルアミノ基、アリールアミノ基、アルキルアリールアミノ基、ジアリールアミノ基等の置換アミノ基または非置換のアミノ基を示す。置換アミノ基におけるアルキル基の例としてはＲ_１ ，Ｒ_２ に記したアルキル基、アリール基としては、たとえば、フェニル基、トリル基、ナフチル基等が挙げられる。
【００１７】
上記一般式［Ｉ］で示されるカチオン塩化合物の構造式の具体例のいくつかを下記表１にその番号（Ｎｏ）と共に示す。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。
【００１８】
【表１】

【００１９】
なお、本発明の思想は、従来技術とは全く異なるものであり、そのことをここで説明する。従来技術では、それぞれ十分実用可能な電子写真特性を有する感度の異なる２種のキャリア発生物質を併用し、それらの混合比率を変えることにより求める感度に調整している。この場合、通常、感度調整出来る範囲は、混合するそれぞれのキャリア発生物質の感度の中間となる。しかしながら、本発明に係る一般式［Ｉ］のカチオン塩化合物は、半導体レーザー光源の８００ｎｍ前後の長波長域に対し光キャリア発生能を有していない、すなわちキャリア発生物質ではなく、光キャリア発生能を有しているオキシチタニウムフタロシアニンをカチオン塩化合物で置き換える増量剤として機能している。さらに、カチオン塩化合物とオキシチタニウムフタロシアニンの混合比率を変えることにより、感度以外の感光体特性を悪化させることなく、容易に低感度から高感度まで広い範囲で感度を調整することができるという特徴を有する。
【００２０】
このようなキャリア発生物質への増量剤の混合は、必ずしも一律的な選択手段があるというものではなく、多くの場合、感度は調整できるものの、残留電位、暗減衰等の他の感光体特性を悪化させてしまう。本発明においても数多くの無機および有機化合物の中から検討の積み重ねによって前記オキシチタニウムフタロシアニン顔料とカチオン塩化合物の組み合わせを決定したものである。
【００２１】
本発明の感光体によれば、露光ビームによりスポット露光して静電潜像を形成する工程と、この静電潜像を現像剤により現像する工程を用いる画像形成プロセスにおいて電子写真用感光体の感度を、画質が鮮鋭であるようにここで用いる露光光源が必要とする感度に合わせることが可能となる。
【００２２】
次に感光層を塗布するための塗布液の製造方法は特に限定されず、例えば上記のオキシチタニウムフタロシアニンおよびカチオン塩化合物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カチオン塩化合物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、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方法が挙げられる。
【００２３】
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。
結着樹脂としては電子写真用感光体に使用される種々の物が使用でき、例えば、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。
【００２４】
オキシチタニウムフタロシアニンおよびカチオン塩化合物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。結着樹脂とオキシチタニウムフタロシアニン粒子あるいはカチオン塩化合物粒子との混合方法としては例えば、オキシチタニウムフタロシアニン粒子あるいはカチオン塩化合物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。
【００２５】
オキシチタニウムフタロシアニンとカチオン塩化合物の含有比率は、特に限定されないが、通常、フタロシアニンが１重量部に対してカチオン塩化合物が０．０１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カチオン塩化合物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、公知のいずれかの方法を用いても差し支えない。
【００２６】
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よい。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カチオン塩化合物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カチオン塩化合物の総量が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カチオン塩化合物の濃度は、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。
【００２７】
また、必要に応じてキャリア輸送物質を含むことができる。キャリア輸送物質としては例えば、２，４，７−トリニトロフルオレノン、テトラシアノキノ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。キャリア輸送物質と結着樹脂の割合は、通常、結着樹脂１００重量部に対してキャリア輸送物質が５〜５００重量部の範囲より使用される。
【００２８】
この様にして調整された分散液を用いて、導電性支持体上にキャリア発生層を形成させ、その上にキャリア輸送層を積層させて感光層を形成する、或いは、導電性支持体上にキャリア輸送層を形成しその上に前記分散液を用いてキャリア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分散液を用いてキャリア発生層を形成させ単層の感光層とする等のいずれの構造でも感光層を形成することができる。ただし、本発明の効果を得るためには、フタロシアニンおよびアゾレーキ化合物が同一の感光層中に含有されることが必要である。
【００２９】
キャリア発生層の膜厚はキャリア輸送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キャリア輸送層の膜厚は５μｍ〜６０μｍが好適である。キャリア発生層のみの単独構造で感光層を形成する場合のキャリア発生層の膜厚は５μｍ〜６０μｍの範囲が好適である。
キャリア輸送層を設ける場合、そこに使用されるキャリア輸送物質としては、前記キャリア輸送物質として例示した材料を使用することができる。これらキャリア輸送物質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。
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、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。
【００３０】
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。
【００３１】
【実施例】
以下、本発明を実施例により更に詳細に説明するが、本発明はこれらに限定されるものではない。
［実施例１］
図１に示すＣｕＫα線によるＸ線回折スペクトルを有するＤ型のオキシチタニウムフタロシアニン５重量部、前記表１のカチオン塩化合物Ｎｏ．１を５重量部に１，２−ジメトキシエタン２００重量部を加え、サンドグラインドミルで１０時間粉砕して、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％１，２−ジメトキシエタン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となるようにキャリア発生層を設けた。
このキャリア発生層の上に、次に示すヒドラゾン化合物５６重量部と
【００３２】
【化５】

【００３３】
次に示すヒドラゾン化合物１４重量部、
【００３４】
【化６】

【００３５】
及び下記のシアノ化合物１．５重量部
【００３６】
【化７】

【００３７】
及びポリカーボネート樹脂（三菱化学（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となるようにキャリア輸送層を設けた。この様にして得られた感光体を感光体Ａとする。
【００３８】
［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カチオン塩化合物Ｎｏ．１との混合比に代えて、オキシチタニウムフタロシアニン２重量部、カチオン塩化合物Ｎｏ．１を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感光体Ｂとする。
【００３９】
［実施例３］
実施例１において用いられたカチオン塩化合物Ｎｏ．１に代えて、カチオン塩化合物Ｎｏ．２を用いた他は、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。
【００４０】
［実施例４］
実施例２において用いられたカチオン塩化合物Ｎｏ．１に代えて、カチオン塩化合物Ｎｏ．２を用いた他は、実施例２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。
【００４１】
［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を１０重量部とし、カチオン塩化合物を用いなかった他は、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。
【００４２】
［比較例２］
実施例１において用いられたカチオン塩化合物を１０重量部とし、オキシチタニウムフタロシアニンを用いなかった他は、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。
【００４３】
［比較例３］
実施例３において用いられたカチオン塩化合物を１０重量部とし、オキシチタニウムフタロシアニンを用いなかった他は、実施例３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。
【００４４】
［評価］
得られた各感光体について、初期電気特性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３５ｍＡのコロナ電流により感光体を負帯電した帯電電位（Ｖｏ）、次いで７８０ｎｍ単色光を連続的に露光し、表面の電位が−７００ｖから−３５０ｖに減少するのに要した半減露光量（Ｅ_１／２ ）および残留電位（Ｖｒ）を測定した。その結果を表２に示す。
【００４５】
【表２】

【００４６】
表２より、比較感光体ＦおよびＧでは、半減露光量が求められないほど帯電電位と残留電位の差が小さいが、この差は暗減衰による電位低下であり、いずれの感光体も７８０ｎｍ単色光に対して光キャリア発生能を有していないことがわかる。一方、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に比べて残留電位がほぼ同等であり、オキシチタニウムフタロシアニンとカチオン塩化合物の混合により特性の悪化をきたしていないことがわかる。また、感光体Ａ，Ｂ，ＥおよびＣ，Ｄ，Ｅをそれぞれ比較すると、オキシチタニウムフタロシアニンとカチオン塩化合物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がわかる。
【００４７】
【発明の効果】
本発明によれば、画像形成プロセスにおいて露光ビームによりスポット露光して静電潜像を形成する工程と、この静電潜像を現像剤により現像する工程を用いる画像形成プロセスに用いる電子写真用感光体の感度を、画質が鮮鋭であるようにここで用いる露光光源が必要とする感度に合わせることが可能であり、文字の太りや細りまた解像度などの問題を解決し、高品質な画像を得るための画像形成プロセスに好適な電子写真用感光体を提供できる。
【図面の簡単な説明】
【図１】実施例１で用い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。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a photoconductor for electrophotography. In particular, the present invention relates to an electrophotographic photosensitive member suitably used for a printer or the like using long-wavelength light such as a semiconductor laser as a light source.
[0002]
[Prior art]
Since the discovery of phthalocyanine compounds having good photoconductivity, many studies have been made as photoelectric conversion materials, and they have been used, for example, in electrophotographic photoreceptors. In recent years, research and development of laser beam printers using laser light as a light source instead of the conventional white light and having advantages of high speed, high image quality and non-impact have been actively conducted. In particular, the recent development of semiconductor lasers has been remarkable, and it has become possible to reduce the price of a small and stable laser oscillator, and it is being used as a light source for an electrophotographic photosensitive member. Since the wavelength of such a semiconductor laser light source is around 800 nm, a photoreceptor having high sensitivity to a long wavelength region around 800 nm is strongly desired. Squaric acid, methine dyes, cyanine dyes, pyrylium dyes, thiapyrylium dyes, polyazo dyes, phthalocyanine dyes, and the like are known as organic photoconductive materials that satisfy this requirement. Of these, squaric acid, methine dyes, cyanine dyes, pyrylium dyes, and thiapyrylium dyes are relatively easy to increase the spectral sensitivity, but lack practical stability such as repeated use. In addition, polyazo dyes have difficulty in increasing the absorption wavelength and have difficulty in production. On the other hand, phthalocyanine dyes can be synthesized relatively easily, have an absorption peak in the wavelength region of 600 nm or more, and have a longer wavelength than other dyes. It is expected and widely studied as a carrier generator for light sources.
[0003]
Phthalocyanine dyes 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. Some examples have been reported in which is selected as a photoreceptor for electrophotography. For example, it is reported that oxytitanium phthalocyanine has various crystal forms, and there is a great difference in chargeability, dark decay, sensitivity, and the like depending on the crystal form. In JP-A-59-49544, the crystal forms of oxytitanium phthalocyanine include Bragg angles (2θ ± 0.2 °) = 9.2 °, 13.1 °, 20.7 °, 26.2 °, Those which give a strong diffraction peak at 27.1 ° are described as suitable, and an X-ray diffraction spectrum is shown. In JP-A-59-166959, a vapor-deposited film of oxytitanium phthalocyanine is left in 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 angles (2θ) = 7.5 °, 12.6 °, 13.0 °, 25.4 °, 26.2 °, 28. It is shown to show a strong diffraction peak at 6 °.
[0004]
[Problems to be solved by the invention]
However, the sensitivity of the electrophotographic photoreceptor is almost uniquely determined by the photoconductive material used, and thus does not always match the light sensitivity required by the exposure light source. May occur. For example, if the sensitivity is too high with respect to the exposure light source, thickening of characters occurs and the resolution is reduced. Further, the amount of toner consumption also increases. For example, when a photoconductor is used for a cartridge used in a printer or the like, the life of the cartridge is affected. In this way, restrictions are imposed on the construction of an image forming process for obtaining a high-quality image.
In order to change the photosensitivity of the photoconductor, for example, when a photoconductive material is used by a dispersion method, a method of changing a binder resin or an organic solvent to be used is known. In practice, it is difficult to change the sensitivity as required, since the usable components are limited.
[0005]
Further, there has been reported an example in which light sensitivity is adjusted by using a mixture of a plurality of phthalocyanines. For example, in Japanese Patent Application Laid-Open No. 62-272272, α-type oxytitanium phthalocyanine and β-type oxytitanium phthalocyanine, or in JP-A-2-183261, Bragg angles (2θ) = 9.6 °, 11.7 °, 24 Different crystals such as oxytitanium phthalocyanine having crystal forms giving peaks at 0.1 ° and 27.2 ° and oxytitanium phthalocyanine having crystal forms giving peaks at 6.9 °, 15.5 ° and 23.4 ° Oxytitanium phthalocyanine is mixed and the sensitivity is adjusted by changing the mixing ratio. In JP-A-2-280169, another type of phthalocyanine compound such as metal-free phthalocyanine and copper phthalocyanine is added to oxytitanium phthalocyanine. Shown how to mix and adjust the sensitivity etc. That.
However, the photoreceptors shown in these examples have problems such that the sensitivity adjustment range is narrow, so that the light sensitivity can be adjusted only to the light sensitivity of a specific exposure light source, or the potential fluctuation is large when used repeatedly. Yes, it wasn't really satisfactory.
[0006]
[Means for Solving the Problems]
An object of the present invention is to form an electrostatic latent image by spot exposure with an exposure beam in an image forming process, and an electrophotographic process used in an image forming process using a step of developing the electrostatic latent image with a developer. An object of the present invention is to provide an electrophotographic photoconductor in which the sensitivity of the photoconductor can be adjusted to the sensitivity required by the exposure light source used here so that the image quality is sharp.
An object of the present invention is to provide a photoreceptor for electrophotography comprising at least a photosensitive layer provided on a conductive support, wherein a crystalline oxytitanium phthalocyanine and a cation salt compound represented by the following general formula [I] are used. It is achieved by containing
[0007]
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[0008]
(In the above formula, X represents a halogen atom. Further, R ₁ and R ₂ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₃ and R ₄ Represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted amino group.)
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The crystalline oxytitanium phthalocyanine used in the present invention includes, for example, the following general formula [II]
[0010]
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[0011]
(In the formula, X represents a halogen atom, and n represents a number from 0 to 1.)
Are shown. In the general formula [II], those in which X is a chlorine atom and n is from 0 to 0.5 are preferable.
The method for synthesizing the crystalline oxytitanium phthalocyanine used in the present invention is not particularly limited. For example, from 1,2-dicyanobenzene (orthophthalonitrile) and a titanium compound, for example, according to the following reaction formula (1) or (2): It can be easily synthesized.
[0012]
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[0013]
That is, 1,2-dicyanobenzene and a halide of titanium are reacted by heating in an inert solvent. As the titanium compound, titanium tetrachloride, titanium trichloride, titanium tetrabromide and the like can be used. Examples of the inert solvent include reactions of trichlorobenzene, α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenyl ether, diphenylmethane, diphenylethane, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and the like. A high boiling organic solvent which is inert to water is preferred. The reaction temperature is usually preferably from 130 to 300 ° C, particularly preferably from 180 to 250 ° C. The dichlorotitanium phthalocyanine formed after the reaction is filtered off and washed with the solvent used for the reaction to remove impurities generated during the reaction and unreacted raw materials.
[0014]
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. Oxytitanium phthalocyanine is obtained by treating the obtained dichlorotitanium phthalocyanine with an organic solvent, hydrolysis and the like.
For example, by subjecting an organic solvent treatment disclosed in JP-A-2-308863, JP-A-3-50270, and JP-A-3-59077 to obtain oxytitanium phthalocyanine of a desired crystal form directly from dichlorotitanium phthalocyanine. Can be. Further, the oxytitanium phthalocyanine obtained by the hydrolysis treatment is subjected to, for example, a hot water treatment disclosed in JP-A-62-67094 or a mechanical grinding treatment disclosed in JP-A-2-215866. Thus, a desired crystal form can be obtained.
[0015]
Further, the crystalline oxytitanium phthalocyanine used in the present invention is not limited to the crystalline oxytitanium phthalocyanine produced by the above-mentioned production method. Crystalline oxytitanium phthalocyanine that can be produced by treatment and produced by any production method can be used as the crystalline oxytitanium phthalocyanine in the present invention.
[0016]
In the cation salt compound represented by the general formula [I] according to the present invention, X represents a halogen atom such as a fluorine atom and a chlorine atom. R ₁ and R ₂ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and a t-butyl group. R ₃ and R ₄ are each independently a hydrogen atom, a fluorine atom, a halogen atom such as a chlorine atom, an alkylamino group, a dialkylamino group, an arylamino group, an alkylarylamino group, a diarylamino group, etc. It represents a substituted amino group or an unsubstituted amino group. Examples of the alkyl group in the substituted amino group include the alkyl groups described in R ₁ and R ₂ , and examples of the aryl group include a phenyl group, a tolyl group, and a naphthyl group.
[0017]
Some specific examples of the structural formula of the cation salt compound represented by the general formula [I] are shown in Table 1 below together with the number (No). Of course, the present invention is not limited to only these specific examples.
[0018]
[Table 1]

[0019]
It should be noted that the concept of the present invention is completely different from the prior art, and that will be described here. In the prior art, two kinds of carrier generating substances having different sensitivities, each having sufficiently practical electrophotographic characteristics, are used in combination, and the sensitivity is adjusted to a desired level by changing a mixing ratio thereof. In this case, the range in which the sensitivity can be adjusted is usually between the sensitivities of the carrier generating substances to be mixed. However, the cation salt compound of the general formula [I] according to the present invention does not have photocarrier generation ability in a long wavelength region of about 800 nm of a semiconductor laser light source, that is, it is not a carrier generation substance but a photocarrier generation ability. And functions as a bulking agent for replacing oxytitanium phthalocyanine having a cation salt compound. Furthermore, by changing the mixing ratio of the cation salt compound and oxytitanium phthalocyanine, the sensitivity can be easily adjusted in a wide range from low to high without deteriorating the photoreceptor characteristics other than the sensitivity. Have.
[0020]
Mixing the extender with such a carrier-generating substance does not necessarily have a uniform selection means. In many cases, the sensitivity can be adjusted, but other photoreceptor characteristics such as residual potential and dark decay may be reduced. Will make it worse. Also in the present invention, the combination of the oxytitanium phthalocyanine pigment and the cation salt compound is determined through repeated studies from a number of inorganic and organic compounds.
[0021]
According to the photoreceptor of the present invention, an electrophotographic photoreceptor is used in an image forming process using a step of forming an electrostatic latent image by spot exposure with an exposure beam and a step of developing the electrostatic latent image with a developer. The sensitivity can be adjusted to the sensitivity required by the exposure light source used here so that the image quality is sharp.
[0022]
Next, the method for producing a coating solution for coating the photosensitive layer is not particularly limited. For example, the above oxytitanium phthalocyanine and a cation salt compound are mixed and dispersed in a dispersion medium, and finally mixed with a binder resin. Adjusted as a coating solution for applying the photosensitive layer in the state of, or phthalocyanine and a cationic salt compound are respectively dispersed in a dispersion medium, and further adjusted to a state of being mixed with a binder resin. Of the resulting mixture to form a coating solution for coating the photosensitive layer.
[0023]
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 used as a mixture.
As the binder resin, various substances used for electrophotographic photoreceptors can be used, for example, polyvinyl butyral, polyvinyl acetal, polyester, polycarbonate, polystyrene, polyester carbonate, polysulfone, polyimide, polymethyl methacrylate, polyvinyl chloride, etc. Or a copolymer thereof, a phenoxy, epoxy, silicone resin, or a partially cross-linked cured product thereof, alone or in combination of two or more.
[0024]
As a method for dispersing the oxytitanium phthalocyanine and the cation salt compound, a known method such as a ball mill, a sand grind mill, a planetary mill, a roll mill, or the like can be used. As a method of mixing the binder resin and the oxytitanium phthalocyanine particles or the cation salt compound particles, for example, during the dispersion treatment of the oxytitanium phthalocyanine particles or the cation salt compound particles, the binder resin is kept in a powder state or a polymer solution thereof is added and simultaneously dispersed. Or a method of mixing the dispersion in the polymer solution of the binder resin, or a method of mixing the polymer solution in the dispersion.
[0025]
The content ratio of the oxytitanium phthalocyanine to the cation salt compound is not particularly limited, but usually, the phthalocyanine is used in an amount of 0.01 to 10 parts by weight per 1 part by weight of the cation salt compound. The phthalocyanine and the cation salt compound are each separately subjected to dispersion treatment in a dispersion medium, and further adjusted to a state of being mixed with a binder resin, and the adjusted liquids are mixed to form a coating liquid for coating the photosensitive layer. The method of mixing the liquids prepared in each case is as follows: mixing using a mechanical stirrer, a homomixer, a homogenizer, or the like, or mixing by applying ultrasonic waves, or any other known method may be used. Absent.
[0026]
The obtained dispersion may be diluted with various solvents in order to make the liquid properties suitable for coating. As the solvent, for example, the solvents exemplified as the dispersion medium can be used. The ratio of the phthalocyanine and the cation salt compound to the binder resin is not particularly limited, but generally the total amount of the phthalocyanine and the cation salt compound is used in the range of 5 to 500 parts by weight based on 100 parts by weight of the resin. In this dispersion, the concentration of the phthalocyanine and the cation salt compound is preferably used in the range of 0.1% by weight to 10% by weight.
[0027]
Further, a carrier transporting material can be included as needed. Examples of the carrier transporting substance include electron-withdrawing substances such as 2,4,7-trinitrofluorenone and tetracyanoquinodimethane; carbazole, indole, imidazole, oxazole, oxadiazole, pyrazoline, and heterocyclic compounds such as thiazole; An electron donating substance such as an aniline derivative, a hydrazone compound, an aromatic amine derivative, a stilbene derivative, or a polymer having a group consisting of these compounds in a main chain or a side chain is exemplified. The ratio of the carrier transporting substance to the binder resin is usually in the range of 5 to 500 parts by weight based on 100 parts by weight of the binder resin.
[0028]
Using the dispersion prepared in this manner, a carrier generation layer is formed on a conductive support, and a carrier transport layer is laminated thereon to form a photosensitive layer, or on the conductive support. A carrier transport layer is formed, and a carrier generation layer is formed thereon using the above-mentioned dispersion to form a photosensitive layer. Alternatively, the photosensitive layer can be formed by any structure such as forming a carrier generation layer on the conductive support using the dispersion to form a single photosensitive layer. However, in order to obtain the effects of the present invention, it is necessary that the phthalocyanine and the azo lake compound are contained in the same photosensitive layer.
[0029]
When the photosensitive layer is formed by laminating the carrier generating layer and the carrier transporting layer, the thickness is preferably in the range of 0.1 μm to 10 μm, and the thickness of the carrier transporting layer is preferably 5 μm to 60 μm. When the photosensitive layer is formed with a single structure including only the carrier generation layer, the thickness of the carrier generation layer is preferably in the range of 5 μm to 60 μm.
When a carrier transporting layer is provided, the material exemplified as the carrier transporting material can be used as the carrier transporting material used therein. A binder resin is blended with these carrier transporting materials as needed. As the binder resin, for example, those exemplified above as the binder resin can be used. The photosensitive layer may contain various additives such as an antioxidant and a sensitizer as needed.
The photosensitive layer is provided on a conductive support.As the conductive support, a metal material such as aluminum, stainless steel, and nickel, and a conductive layer such as aluminum, copper, palladium, tin oxide, and indium oxide on the surface. An insulating support such as a provided polyester film, paper, or glass is used.
[0030]
A well-known barrier layer, which is usually used, may be provided between the conductive support and the photosensitive layer. As the barrier layer, for example, an anodized aluminum film, an inorganic layer such as aluminum oxide and aluminum hydroxide, an organic layer such as polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. Layers are used. The thickness of the barrier layer is preferably in the range of 0.1 μm to 20 μm, and most preferably in the range of 0.1 μm to 10 μm.
[0031]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.
[Example 1]
5 parts by weight of D-type oxytitanium phthalocyanine having an X-ray diffraction spectrum by CuKα ray shown in FIG. 200 parts by weight of 1,2-dimethoxyethane were added to 5 parts by weight of No. 1 and the mixture was pulverized for 10 hours with a sand grind mill to perform atomization and dispersion treatment. Next, a dispersion was prepared by mixing 5 parts by weight of polyvinyl butyral (trade name "Denka Butyral"# 6000C, manufactured by Denki Kagaku Kogyo KK) with a 10% 1,2-dimethoxyethane solution. Next, a carrier generation layer was provided on an aluminum-deposited surface on which the dispersion was deposited on a polyester film so as to have a thickness of 0.4 μm after drying with a bar coater.
On this carrier generation layer, 56 parts by weight of the following hydrazone compound were added:
Embedded image

[0033]
14 parts by weight of the following hydrazone compound,
[0034]
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[0035]
And 1.5 parts by weight of the following cyano compound:
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[0037]
And a solution obtained by dissolving 100 parts by weight of a polycarbonate resin (trade name “NOVAREX” 7030A, manufactured by Mitsubishi Chemical Corporation) in 1,000 parts by weight of 1,4-dioxane is applied by a film applicator, and the film thickness after drying is adjusted. A carrier transport layer was provided so as to have a thickness of 17 μm. The photoreceptor thus obtained is referred to as photoreceptor A.
[0038]
[Example 2]
The oxytitanium phthalocyanine and the cation salt compound No. 1 and 2 parts by weight of oxytitanium phthalocyanine, cation salt compound No. A photoconductor was prepared by the same way as that of Example 1 except that 1 was changed to 8 parts by weight. The photoreceptor thus obtained is referred to as photoreceptor B.
[0039]
[Example 3]
The cation salt compound No. 1 used in Example 1 was used. In place of the cationic salt compound No. 1 A photoconductor was prepared in the same manner as in Example 1 except that No.2 was used. The photoconductor obtained in this manner is referred to as photoconductor C.
[0040]
[Example 4]
The cation salt compound No. 2 used in Example 2 was used. In place of the cationic salt compound No. 1 A photoconductor was prepared by the same way as that of Example 2 except that Sample No. 2 was used. The photoreceptor thus obtained is referred to as photoreceptor D.
[0041]
[Comparative Example 1]
A photoconductor was prepared by the same way as that of Example 1 except that oxytitanium phthalocyanine used in Example 1 was changed to 10 parts by weight and a cation salt compound was not used. The photoreceptor thus obtained is referred to as comparative photoreceptor E.
[0042]
[Comparative Example 2]
A photoconductor was prepared by the same way as that of Example 1 except that the amount of the cation salt compound used in Example 1 was 10 parts by weight and oxytitanium phthalocyanine was not used. The photoreceptor thus obtained is referred to as comparative photoreceptor F.
[0043]
[Comparative Example 3]
A photoconductor was prepared by the same way as that of Example 3 except that the amount of the cation salt compound used in Example 3 was 10 parts by weight and oxytitanium phthalocyanine was not used. The photoreceptor thus obtained is referred to as comparative photoreceptor G.
[0044]
[Evaluation]
The initial electrical characteristics of each of the obtained photoreceptors were measured by an electrostatic copying paper tester (Model EPA-8100, manufactured by Kawaguchi Electric Works). That is, the charging potential (Vo) obtained by negatively charging the photoreceptor with a corona current of 35 mA in a dark place, and then a monochromatic light of 780 nm is continuously exposed to reduce the half required for the surface potential to decrease from -700 V to -350 V. The exposure amount (E _1/2 ) and the residual potential (Vr) were measured. Table 2 shows the results.
[0045]
[Table 2]

[0046]
As shown in Table 2, the difference between the charged potential and the residual potential was so small that the half-exposure amount could not be obtained for the comparative photoconductors F and G, but this difference was a potential decrease due to dark decay. It does not have photocarrier generation ability with respect to. On the other hand, the photoconductors A, B, C, and D have high sensitivity to monochromatic light of 780 nm, have substantially the same residual potential as the comparative photoconductor E, and have a mixture of oxytitanium phthalocyanine and a cation salt compound. It can be seen that the characteristics did not deteriorate. Comparing the photoconductors A, B, E and C, D, E, respectively, shows that the sensitivity can be freely controlled over a wide range by changing the mixing ratio of oxytitanium phthalocyanine and the cation salt compound.
[0047]
【The invention's effect】
According to the present invention, an electrophotographic photosensitive member used in an image forming process using a step of forming an electrostatic latent image by spot exposure with an exposure beam in an image forming process, and a step of developing the electrostatic latent image with a developer It is possible to adjust the sensitivity of the body to the sensitivity required by the exposure light source used here so that the image quality is sharp, solve problems such as thick and thin characters and resolution, and obtain high quality images Electrophotographic photoreceptor suitable for the image forming process for the purpose.
[Brief description of the drawings]
FIG. 1 is an X-ray diffraction spectrum of oxytitanium phthalocyanine used in Example 1.

Claims (1)

An electrophotographic photosensitive member having at least a photosensitive layer provided on a conductive support, characterized in that the photosensitive layer contains crystalline oxytitanium phthalocyanine and a cation salt compound represented by the following general formula [I]. Electrophotographic photoreceptor.

(In the above formula, X represents a halogen atom. Further, R ₁ and R ₂ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₃ and R ₄ Represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted amino group.)

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