JP2004061635A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having high sensitivity in a long wavelength region and excellent and constant half tone reproducibility. <P>SOLUTION: In the electrophotographic photoreceptor constituted by laminating a photoreceptive layer incorporating at least charge generating material, charge transfer material and binding resin on a conductive supporting body, the charge generating material is oxy-titanium phthalocyanine, which has a maximum peak at 7.5° in a Bragg angle (2θ±0.2°) in X-ray diffraction spectrum using CuKα as a beam source, and the strength of other diffraction peaks is the ≤20% of the strength of the diffraction peak at 7.5°, and the charge transfer material incorporates a compound expressed by a general expression (1) or (2). <P>COPYRIGHT: (C)2004,JPO

Description

（式中、Ｒ_１及びＲ_２は、各々独立に置換基を有してもよい炭素数１〜６のアルキル基を表し、Ｒ_３は、水素原子又は少なくとも一つのアルキル基が炭素数２以上のジアルキルアミノ基のいずれかを表す。）
【００３７】
一般式（２）
【化５】

（式中、Ｒ_４〜Ｒ_７は、各々同一であっても異なっていてもよく、各々独立に水素原子、ハロゲン原子、炭素数１〜６のアルキル基若しくはアルコキシ基、又は置換基を有してもよいアリール基のいずれかを表し、Ｒ_８は水素原子、ハロゲン原子、炭素数１〜６のアルキル基若しくはアルコキシ基、置換基を有してもよいアリール基、又は置換基を有してもよいアルケニル基若しくはアルカジエニル基、若しくは一般式（３）のいずれかを表し、ｍは０又は１の整数を表す。）
【００３８】
一般式（３）
【化６】

（式中、Ｒ_９、Ｒ_１０は、各々同一であっても異なっていてもよく、各々独立に水素原子、ハロゲン原子、炭素数１〜６のアルキル基若しくはアルコキシ基、又は置換基を有してもよいアリール基のいずれかを表し、ｎは０又は１の整数を表す。）
上記電荷移動材料は、オキシチタニウムフタロシアニンとの相性がよく、本発明の電子写真感光体は、高感度かつ低残留電位という優れた電気特性を示すものである。
一般式（１）に示す化合物において、特に式（４）及び式（５）に示す化合物がオキシチタニウムフタロシアニンとの相性がよく好ましい。
【００３９】
式（４）
【化７】

【００４０】
式（５）
【化８】

また、一般式（２）に示す化合物において、特に式（６）、式（７）、式（８）、式（９）に示す化合物がオキシチタニウムフタロシアニンとの相性がよく好ましい。
【００４１】
式（６）
【化９】

【００４２】
式（７）
【化１０】

【００４３】
式（８）
【化１１】

【００４４】
式（９）
【化１２】

【００４５】
また、一般式（１）から選ばれる化合物と一般式（２）から選ばれる化合物を同時に電荷移動材料として用いても、よい特性が得られて好ましい。
【００４６】
上記電荷移動材料に加えて、他の電荷移動材料を含有させることもできる。他の電荷移動材料としては、ポリビニルカルバゾール、ハロゲン化ポリビニルカルバゾール、ポリビニルピレン、ポリビニルインドロキノキサリン、ポリビニルベンゾチオフェン、ポリビニルアントラセン、ポリビニルアクリジン、ポリビニルピラゾリン、ポリアセチレン、ポリチオフェン、ポリピロール、ポリフェニレン、ポリフェニレンビニレン、ポリイソチアナフテン、ポリアニリン、ポリジアセチレン、ポリヘプタジイエン、ポリピリジンジイル、ポリキノリン、ポリフェニレンスルフィド、ポリフェロセニレン、ポリペリナフチレン、ポリフタロシアニン等の導電性高分子化合物を用いることができる。又、低分子化合物として、トリニトロフルオレノン、テトラシアノエチレン、テトラシアノキノジメタン、キノン、ジフェノキノン、ナフトキノン、アントラキノン及びこれらの誘導体、アントラセン、ピレン、フェナントレン等の多環芳香族化合物、インドール、カルバゾール、イミダゾール等の含窒素複素環化合物、フルオレノン、フルオレン、オキサジアゾール、オキサゾール、ピラゾリン、ヒドラゾン、トリフェニルメタン、トリフェニルアミン、エナミン、スチルベン等を使用することができる。また、ポリエチレンオキシド、ポリプロピレンオキシド、ポリアクリロニトリル、ポリメタクリル酸等の高分子化合物にＬｉイオン等の金属イオンをドープした高分子固体電解質等も用いることができる。さらに、テトラチアフルバレン−テトラシアノキノジメタンで代表される電子供与性化合物と電子受容性化合物で形成された有機電荷移動錯体等も用いることができ、これらを１種だけ添加して又は２種以上の化合物を混合して添加して、所望の感光体特性を得ることができる。
【００４７】
本発明の電子写真感光体１、２を製造するための塗布液には、特性を損なわない範囲で、酸化防止剤、紫外線吸収剤、ラジカル捕捉剤、軟化剤、硬化剤、架橋剤等を添加して、感光体の特性、耐久性、機械特性の向上を図ることができる。特に、フェノール系酸化防止剤は感光体の耐久性向上に寄与し有用である。さらに、分散安定剤、沈降防止剤、色分かれ防止剤、レベリング剤、消泡剤、増粘剤、艶消し剤等を添加すれば、感光体の仕上がり外観や、塗布液の寿命を改善できる。
加えて、感光層１４、２４の上に、ポリビニルホルマール樹脂、ポリカーボネート樹脂、フッ素樹脂、ポリウレタン樹脂、シリコーン樹脂等の有機薄膜や、シランカップリング剤の加水分解物で形成されるシロキサン構造体から成る薄膜を成膜して表面保護層を設けてもよく、その場合には、感光体の耐久性が向上するので好ましい。この表面保護層は、耐久性向上以外の他の機能を向上させるために設けてもよい。
本発明の電子写真感光体が搭載される電子写真装置としては、通常、帯電方式はブラシ、ローラーなどの接触式、スコロトロン、コロトロン等の非接触式の、いずれの方式でもよく、正負いずれの帯電電荷でもよい。露光方式は、ＬＥＤ，ＬＤ等いずれでもよい。現像方式は、２成分、１成分、磁性／非磁性いずれでもよい。転写方式もローラー、ベルト等いずれでもよい。
【００４８】
【実施例】
以下、本発明を実施例と比較例により詳しく説明するが、本発明はこれに限定されるものではない。
【００４９】
（実施例１）
塗布液の作成
アルキド樹脂とメラミン樹脂を６／４の重合割合で混合し、酸化チタンを混合樹脂に対する重量比１／３の割合で用意し、メチルエチルケトンに溶解分散し、下引層用塗工液を準備する。次にアルミ合金からなる円筒状基体を該下引層用塗工液に浸漬塗工し、１３０℃で２０分乾燥し、膜厚０．８μｍの下引層を形成した。
次に図３のＸ線回折ピークを示すβ型オキシチタニウムフタロシアニン粉末１０ｇをガラスビーズとともにＳＵＳポットに入れ、サンドミル分散装置で４０時間乾式粉砕し、無定形のオキシチタニウムフタロシアニンとする。次いで、１，１，２−トリクロロエタン／ジクロロメタン／テトラヒドロフラン＝７／２／１の割合で５００ｍｌ用意し、これにポリビニルブチラール樹脂５ｇを溶解し、３０分間ミリング後、上記ＳＵＳポットに入れ２０時間分散し、得られた分散液をろ過してガラスビーズを取り去り、電荷発生層用塗布液を作成した。これを浸漬塗工後乾燥し、膜厚０．２μｍの電荷発生層を形成した。
次にバインダー樹脂としてポリカーボネート樹脂と、電荷移動材料として、式（４）で表されるブタジエン化合物と、酸化防止剤として２，６−ジ−ｔｅｒｔ−ブチル−４−メチル−フェノールとを、重量比１．０：１．０：０．１で用意し、クロロホルムに溶解し、電荷移動層用塗工液を調製した。電荷発生層を形成した基体を該電荷移動層用塗工液に浸漬塗工し、１００℃で６０分乾燥し膜厚２５．０μｍの電荷移動層を形成し、電子写真感光体を作製した。
【００５０】
Ｘ線回折用検体試料の作成
実施例１で得られた感光体表面に事務用カッターで円周方向とそれに交差する円筒軸方向にそれぞれ切込みを入れ、一辺が約２ｃｍの切れ目を形成させる。その切り目の入った部分よりピンセットを用いて感光膜を剥離する。４−メトキシ−４−メチルペンタノン（ＰＴＸ）１５ｍｌを５０ｍｌビーカーに入れ、その中に前記剥離膜を浸漬し、電荷移動層を完全に溶解させた後によくかき混ぜてゲル状の微細片として溶媒中に分散させる。これをテフロン（登録商標）製メンブランフィルター（Ｐｏｒｅ　ｓｉｚｅ　０．２μｍ）で吸引ろ過し、ろ過物をＰＴＸ　１０ｍｌで洗浄する。次にろ過物が内側になるようにメンブランフィルターをシリコン無反射板に密着させ、メンブランフィルターだけを剥がしてシリコン無反射板にオキシチタニウムフタロシアニンを付着させ、それを風乾しＸ線回折の検体試料とした。
【００５１】
Ｘ線回折
上記のように作成された検体試料を測定する場合は、薄膜法にて測定しＸ線源としてＣｕＫα（波長１．５４１７８Å）を用い、Ｘ線入射角度を０．５°とした。なお、オキシチタニウムフタロシアニン粉末を測定する場合は、粉末法にて測定しＸ線源としてＣｕＫα（波長１．５４１７８Å）を用いた。検体試料のＸ線回折図を図４に示す。図４によると、感光層から抽出されたオキシチタニウムフタロシアニンは、７．５°に特徴的な回折ピークを示し、その他９．４°、１５．２°、２２．６°、２７．２°、２８．８°にも回折ピークを示している。さらに、わずかではあるが１３．２°、２４．５°、２５．４°にも回折ピークを示す。回折ピーク強度は、７．５°以外のピーク強度は７．５°の回折ピーク強度の２０％以下となっている。
【００５２】
（実施例２）
実施例１で用いた電荷移動材料に代えて、式（５）で表される電荷移動材料を用い、他は実施例１と同様にして電子写真感光体を作成した。
【００５３】
（実施例３）
実施例１で用いられた電荷移動材料に代えて、式（５）で表される化合物と式（６）で表される化合物を重量比３／７で混合した電荷移動材料を用い、他は実施例１と同様にして電子写真感光体を作成した。
【００５４】
（実施例４）
実施例１で用いられた電荷移動材料に代えて、式（６）で表される電荷移動材料を用い、他は実施例１と同様にして電子写真感光体を作成した。
【００５５】
（実施例５）
実施例１で用いられた電荷移動材料に代えて、式（７）で表される電荷移動材料を用い、他は実施例１と同様にして電子写真感光体を作成した。
【００５６】
（実施例６）
実施例１で用いられた電荷移動材料に代えて、式（８）で表される電荷移動材料を用い、他は実施例１と同様にして電子写真感光体を作成した。
【００５７】
（実施例７）
実施例１で用いられた電荷移動材料に代えて、式（９）で表される電荷移動材料を用い、他は実施例１と同様にして電子写真感光体を作成した。
【００５８】
（比較例１〜３）
実施例１で用いられた電荷移動材料に代えて、式（１０）〜式（１２）で表される電荷移動材料を用い、他は実施例１と同様にして電子写真感光体を作成した。各電子写真感光体をそれぞれ比較例１〜３とした。
【００５９】
式（１０）
【化１３】

【００６０】
式（１１）
【化１４】

【００６１】
式（１２）
【化１５】

【００６２】
（比較例４）
実施例１で用いられた電荷発生材料に代えて、図６で表されるオキシチタニウムフタロシアニンを電荷発生材料として用い、他は実施例１と同様にして電子写真感光体を作成した。
【００６３】
（比較例５）
実施例１で用いられた電荷発生材料に代えて、図７で表されるオキシチタニウムフタロシアニンを電荷発生材料として用い、他は実施例１と同様にして電子写真感光体を作成した。
【００６４】
（比較例６）
実施例１で用いられた電荷発生材料に代えて、図３で表されるオキシチタニウムフタロシアニンを電荷発生材料として用い、他は実施例１と同様にして電子写真感光体を作成した。
【００６５】
電子写真感光体の評価１
ＸＥＲＯＸ社製Ｗｏｒｋ　Ｃｅｎｔｒｅ　６６５の現像器位置に表面電位計を設置した改造機を用い、実施例１〜７及び比較例１〜６で得られた電子写真感光体を搭載した。
初期特性として、帯電後の感光体表面電位Ｖ０と、帯電後露光し、感光体を放置し表面電位が安定したときの残留電位Ｖｅｒを測定した。帯電された感光ドラムを波長７８０ｎｍのレーザー光で露光し、露光後の表面電位を１／２に減衰させるエネルギー量を測定し、Ｅ１／２（μｊ／ｃｍ^２）とした。
以上の評価を測定環境温度２５℃湿度５０％（Ｎ／Ｎ）、測定環境温度１０℃湿度２０％（Ｌ／Ｌ）、測定環境温度４５℃湿度５０％（Ｈ／Ｎ）の三環境で行った。結果を表１に示す。
【００６６】
電子写真感光体の評価２
５Ｋランニング特性として、Ａ４サイズの紙を５，０００枚ランニングし、そのあとの評価１と同様に帯電電位、残留電位及び半減エネルギーを測定した。その時の測定環境は測定環境温度２５℃湿度５０％（Ｎ／Ｎ）で行った。結果を表１に示す。
【００６７】
【表１】

【００６８】
表１から、実施例１〜７は半減露光量が少なく高感度であることがわかる。また、三環境における電位差及び半減エネルギー差がほとんどなく、使用環境に依存しないことがわかる。さらに、５，０００枚ランニング前後のＶ０の差が１０Ｖ以内で、Ｖｅｒの差は５Ｖ以内であり、かつ半減エネルギーにもほとんど差が見られす、繰り返し使用において電位安定性が非常に優れていることがわかる。比較例１及び比較例２は、全体的にＶｅｒが高く、かつ三環境におけるＶｅｒの差が大きいことがわかる。また、電荷発生材料と電荷移動材料の相性があまりよくないため、半減エネルギーが実施例よりも高くなっており、ランニング前後のＶｅｒの差も大きくなっている。
比較例３も全体的にＶｅｒが高く、かつ三環境におけるＶｅｒの差が大きいことがわかる。また、ランニング前後のＶ０及びＶＬの差が大きく、繰り返し安定性に欠けていることがわかる。
比較例４及び比較例５は半減エネルギーについては実施例と同等以上の値であるが、ランニング前後のＶ０の差が３０〜４０Ｖ程度あり、繰り返しにおける電位安定性に欠けており、高い市場要求に答えられないものである。
比較例５は半減エネルギーが極めて高く、かつランニング前後のＶＬの差も大きい。
【００６９】
【発明の効果】
実施例と比較例の特性差からみてもわかるように、本発明の電子写真感光体は、少ない半減エネルギーであるため高感度であり、かつ使用環境に依存しない安定した電位を示し、さらにランニング後でも初期と変わらない特性を示すものであり、高い市場要求に応えられるものである。
【図面の簡単な説明】
【図１】積層型電子写真感光体の一例を示す断面図
【図２】単層型電子写真感光体の一例を示す断面図
【図３】β型オキシチタニウムフタロシアニン粉末のＸ線回折図
【図４】本発明のフタロシアニン組成物のＸ線回折図
【図５】本発明のフタロシアニン組成物のＸ線回折図
【図６】比較例４で用いたオキシチタニウムフタロシアニンのＸ線回折図
【図７】比較例５で用いたオキシチタニウムフタロシアニンのＸ線回折図
【符号の説明】
１、２　電子写真感光体
１１、２１　導電性基体
１２　電荷発生層
１３　電荷移動層
１４、２４　感光層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic photoreceptor containing oxytitanium phthalocyanine having a specific crystal form as a charge generation material and a specific compound as a charge transfer material.
[0002]
[Prior art]
In recent years, as an exposure light source for a non-impact printer employing an electrophotographic method, a long-wavelength light source such as a semiconductor laser or an LED is mainly used. Therefore, an electrophotographic photoreceptor generally uses a charge generating material having sensitivity in a long wavelength region. Conventionally, phthalocyanine pigments have been often used as such a material. It is well known that this phthalocyanine pigment has different sensitivity depending on its crystal form.
Further, with the recent power saving, there is an increasing demand for higher sensitivity of the electrophotographic photosensitive member in order to suppress the output of the exposure light source of the electrophotographic apparatus such as a printer.
[0003]
On the other hand, various methods have been studied for producing an electrophotographic photoreceptor, but a charge generating material or a charge transfer material is dispersed in a solvent together with a binder resin to form a coating solution, which is then converted to a conductive material. A method of forming a thin film on a substrate is generally used.
[0004]
[Problems to be solved by the invention]
Among the phthalocyanine pigments, those having high sensitivity in a long wavelength region include oxytitanium phthalocyanine. Various crystal forms of oxytitanium phthalocyanine are introduced, and among them, one showing a maximum diffraction peak at 27.3 ° is considered to have high sensitivity. However, this oxytitanium phthalocyanine has a high environmental dependency, and its sensitivity changes with an increase or decrease in humidity, and is not suitable for a color printer that requires a halftone reproducibility. As other crystal types, an α type having a main diffraction peak at 7.6 ° and 28.3 ° and a β type having a maximum diffraction peak at 26.3 ° are well known. Lack of sensitivity is not practical.
[0005]
Therefore, there is a demand for an electrophotographic photoreceptor having high sensitivity in a long wavelength region, excellent halftone reproducibility, and a constant. The present invention has been made in order to solve such a problem, and has high sensitivity in a long wavelength region, has no deterioration in electric characteristics even when used repeatedly, and has high stability in a coating liquid. An object of the present invention is to provide an electrophotographic photoreceptor containing oxytitanium phthalocyanine that can use a working solution for a long period of time. Even if a charge generation material having high charge generation efficiency is used, if the compatibility with the charge transfer material is poor, not only sufficient sensitivity cannot be obtained, but also a rise in residual potential and the like will occur. The compatibility between the charge generation material and the charge transfer material has been studied from various viewpoints, but has not been clearly found at present.
[0006]
On the other hand, the market requirements for electrophotographic photoreceptors include electrophotographic photoreceptors that can provide high-quality images from the beginning of use to the end of their service life, regardless of the usage environment, in addition to high sensitivity. Have been. At present, no electrophotographic photoreceptor capable of meeting such a high market demand has been found, and an object of the present invention is to provide such an electrophotographic photoreceptor.
[0007]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, using an oxytitanium phthalocyanine exhibiting a specific X-ray diffraction peak as a charge generating material, an electrophotographic photoreceptor using a charge transfer material of a specific compound However, they have found that the problems of the conventional technique are solved, and have completed the present invention.
The present inventors have solved the conventional problems by specifying the crystal form of oxytitanium phthalocyanine after being applied and formed as a photosensitive layer and combining it with a specific charge transfer material.
[0008]
Conventionally, the X-ray diffraction spectrum of oxytitanium phthalocyanine used for an electrophotographic photoreceptor contains powdery oxytitanium phthalocyanine in a desired crystal form after synthesis, or a resin or a dispersion solvent created when forming a photosensitive layer. The measurement was performed using a pelletized solution of the coating solution as a sample.
[0009]
However, even if the X-ray diffraction spectrum of oxytitanium phthalocyanine is measured before the formation of the photosensitive layer, the crystal form of oxytitanium phthalocyanine contained in the photosensitive layer cannot be accurately determined. That is, there are various external factors in the formation of the photosensitive layer, and the diffraction spectrum may be different before and after the formation of the photosensitive layer. In particular, in a laminated photoreceptor in which a charge transfer layer is stacked on a charge transfer layer, a coating solution containing a charge transfer material is applied to a support, and dried if necessary. A charge transfer layer is formed by applying a coating solution containing the same, and the photosensitive layer is formed by a step of drying and fixing each layer. The contact with a solvent or the like affects the diffraction spectrum of the charge generation material. Therefore, in order to examine the diffraction spectrum of the charge generating material that is actually functioning, it is necessary to take out and measure the charge generating material after forming the photosensitive layer.
[0010]
The present invention has been obtained from the above research results, and the invention according to claim 1 includes a photosensitive layer containing at least a charge generation material, a charge transfer material, and a binder resin on a conductive support. 6. In the electrophotographic photosensitive member formed by lamination, the charge generating material is oxytitanium phthalocyanine, and the oxytitanium phthalocyanine has a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum using CuKα as a radiation source. The charge transfer material has a maximum peak at 5 ° and the other diffraction peak intensity is 20% or less of the diffraction peak intensity at 7.5 °, and the charge transfer material has the general formula (1) and / or the general formula An electrophotographic photoreceptor comprising the compound represented by (2).
[0011]
Peaks other than 7.5 ° include those shown at Bragg angles (2θ ± 0.2 °) of 9.4 °, 15.2 °, 22.5 °, 27.2 °, 28.6 °, and 9 It is preferable to show those at 0.4 °, 15.2 °, 22.5 °, 26.2 °, 27.2 °, and 28.6 °. The peak intensity other than 7.5 ° is 20% or less of the peak intensity at 7.5 °, and more preferably 15% or less.
[0012]
When extracting oxytitanium phthalocyanine from the photosensitive layer, care must be taken so that oxytitanium phthalocyanine does not undergo crystal transition. Further, the photosensitive layer contains a binder resin, a charge transfer material, and the like, which hinder the measurement of the X-ray diffraction spectrum. Therefore, it is necessary to select a solvent that does not change the crystal form of oxytitanium phthalocyanine by removing the binder resin, the charge transfer material, and the like.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The electrophotographic photoreceptor of the present invention contains oxytitanium phthalocyanine having a specific X-ray diffraction spectrum as a charge generating material in a photosensitive layer on a substrate.
[0014]
1 and 2 are cross-sectional views showing the configuration of a preferred embodiment of the electrophotographic photosensitive member according to the present invention.
[0015]
In FIG. 1, reference numeral 1 denotes a function-separated electrophotographic photosensitive member applicable to the present invention, and a charge generation layer 12 and a charge transfer layer 13 are formed on a conductive base 11 in this order. The charge generation layer 12 and the charge transfer layer 13 constitute a photosensitive layer 14.
[0016]
As a method for forming the charge generation layer 12, various methods can be used.For example, a coating solution in which the phthalocyanine composition of the present invention is used as a charge generation material and dispersed or dissolved in a suitable solvent together with a binder resin, It can be formed by coating on a base 11 serving as a predetermined base and drying it as necessary.
[0017]
The charge transfer layer 13 has at least a charge transfer material to be described later. The charge transfer layer 13 is formed, for example, by binding a charge transfer agent onto the charge generation layer 12 serving as a base thereof using a binder resin. Can be formed.
[0018]
Various methods can be used as a method for forming the charge transfer layer 13, but in a normal case, a coating solution in which a charge transfer material is dispersed or dissolved in a suitable solvent together with a binder resin is used as a charge generation layer serving as a base. 12 and a method of drying.
[0019]
In FIG. 1, the charge generation layer 12 and the charge transfer layer 13 can be stacked upside down.
In FIG. 2, reference numeral 2 denotes a single-layer type electrophotographic photosensitive member applicable to the present invention. A photosensitive layer 24 containing a charge generation material and a charge transfer material is formed on a substrate 21. ing.
[0020]
The electrophotographic photoreceptor 2 comprises a substrate 21 on which an oxytitanium phthalocyanine of the present invention is used as a charge generating material, and a coating solution mixed and dispersed together with a charge transfer material described later and a binder resin. 21 and a method of drying.
[0021]
As the substrates 11 and 21 in the electrophotographic photosensitive members 1 and 2, processing of a single metal such as aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, indium, or an alloy thereof is performed. The body can be used.
[0022]
A thin film of a conductive substance may be further formed on the surface of a base such as a metal or an alloy by vapor deposition, plating, or the like. The base itself may be composed of a conductive substance, but it is also possible to form a thin film of the above metal or carbon on a non-conductive plastic plate or film surface by a method such as vapor deposition or plating to have conductivity. Good.
[0023]
When a resin is used as the base, a conductive agent such as metal powder or conductive carbon may be contained in the resin, or a conductive resin may be used as the resin for forming the base.
[0024]
Further, when glass is used for the substrate, its surface may be coated with tin oxide, indium oxide, or aluminum iodide to have conductivity.
[0025]
The type and shape are not particularly limited, and the bases 11 and 21 can be formed using various conductive materials.
[0026]
In general, as the substrates 11 and 21, a cylindrical aluminum tube alone, a surface of which is anodized, or a resin layer formed on an aluminum tube is often used.
[0027]
This resin layer has a function of improving adhesion, a function of preventing a current flowing from the aluminum tube, a function of covering defects on the surface of the aluminum tube, and the like. The resin layer includes various types of resin such as polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, polyamide resin, polyimide resin, nylon resin, alkyd resin, and melamine resin. Resin can be used. These resin layers may be composed of a single resin, or may be composed of a mixture of two or more resins. Further, a metal compound, carbon, silica, resin powder, and the like can be dispersed in the layer. Further, various pigments, an electron accepting substance, an electron donating substance, and the like can be contained for improving properties.
[0028]
As a charge generation material, a diffraction peak having a maximum Bragg angle (2θ ± 0.2 °) of 7.5 ° in the X-ray diffraction spectrum using CuKα as a source and another diffraction peak intensity of 7.5 ° is shown. Oxytitanium phthalocyanine having a peak intensity of 20% or less is used.
[0029]
The diffraction peak shown above is a result measured in a state where oxytitanium phthalocyanine was extracted from the photosensitive layer after the formation of the photosensitive layer. By using this oxytitanium phthalocyanine, it is possible to provide an electrophotographic photoreceptor having excellent sensitivity in a long wavelength region and exhibiting stable characteristics without being affected by a use environment, particularly humidity.
[0030]
In the photosensitive layer, oxytitanium phthalocyanine and azo pigments other than the present invention can be mixed with the oxytitanium phthalocyanine of the present invention in order to obtain an appropriate photosensitivity wavelength and sensitizing effect. These are desirable in that they have good sensitivity compatibility. In addition, for example, monoazo pigments, bisazo pigments, trisazo pigments, polyazo pigments, indigo pigments, sulene pigments, toluidine pigments, pyrazoline pigments, perylene pigments, quinacridone pigments, pyrylium salts and the like can be used.
[0031]
As a binder resin for forming the photosensitive layers 14 and 24, polycarbonate resin, styrene resin, acrylic resin, styrene-acryl resin, ethylene-vinyl acetate resin, polypropylene resin, vinyl chloride resin, chlorinated polyether, vinyl chloride- Vinyl acetate resin, polyester resin, furan resin, nitrile resin, alkyd resin, polyacetal resin, polymethylpentene resin, polyamide resin, polyurethane resin, epoxy resin, polyarylate resin, diallylate resin, polysulfone resin, polyethersulfone resin, polyallyl Sulfone resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, EVA (ethylene / vinyl acetate) resin, ACS (acrylonitrile / chlorinated polyethylene) Styrene) resins, ABS (acrylonitrile butadiene styrene) resin and epoxy arylate such resins.
[0032]
They may be used alone or as a mixture of two or more. It is preferable to use a mixture of resins having different molecular weights because hardness and abrasion resistance can be improved.
[0033]
When the photosensitive layer comprises a charge generation layer and a charge transfer layer, the resin can be applied to either layer.
[0034]
Solvents used for the coating liquid include alcohols such as methanol, ethanol, n-propanol, i-propanol and butanol, pentane, hexane, heptane, octane, cyclohexane, saturated aliphatic hydrocarbons such as cycloheptane, toluene, xylene And hydrocarbons such as dichloromethane, dichloroethane, chloroform and chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran (THF) and methoxyethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. , Ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, esters such as methyl propionate, diethyl ether, dimethoxyethane, tetrahydride Furan, dioxolane, dioxane or ether solvents such as anisole,, N, N-dimethylformamide, there are dimethyl sulfoxide and the like. Among them, ketone-based solvents, ester-based solvents, ether-based solvents, and halogenated hydrocarbon-based solvents are particularly preferable, and these can be used alone or as a mixed solvent of two or more.
[0035]
The electrophotographic photoreceptor of the present invention contains a compound represented by the general formula (1) and / or the general formula (2) as a charge transfer material.
[0036]
General formula (1)
Embedded image

(Where R ₁ And R ₂ Represents an alkyl group having 1 to 6 carbon atoms which may have a substituent, ₃ Represents a hydrogen atom or a dialkylamino group in which at least one alkyl group has 2 or more carbon atoms. )
[0037]
General formula (2)
Embedded image

(Where R ₄ ~ R ₇ May be the same or different, and each independently represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, or an aryl group which may have a substituent. Represents, R ₈ Is a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, an aryl group which may have a substituent, an alkenyl group or an alkadienyl group which may have a substituent, or a compound represented by the general formula (3 ), And m represents an integer of 0 or 1. )
[0038]
General formula (3)
Embedded image

(Where R ₉ , R ₁₀ May be the same or different, and each independently represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, or an aryl group which may have a substituent. And n represents an integer of 0 or 1. )
The charge transfer material has good compatibility with oxytitanium phthalocyanine, and the electrophotographic photoreceptor of the present invention exhibits excellent electrical characteristics such as high sensitivity and low residual potential.
Among the compounds represented by the general formula (1), the compounds represented by the formulas (4) and (5) are particularly preferred because they have good compatibility with oxytitanium phthalocyanine.
[0039]
Equation (4)
Embedded image

[0040]
Equation (5)
Embedded image

Further, among the compounds represented by the general formula (2), the compounds represented by the formulas (6), (7), (8) and (9) are particularly preferred because they have good compatibility with oxytitanium phthalocyanine.
[0041]
Equation (6)
Embedded image

[0042]
Equation (7)
Embedded image

[0043]
Equation (8)
Embedded image

[0044]
Equation (9)
Embedded image

[0045]
Further, it is preferable to use a compound selected from the general formula (1) and a compound selected from the general formula (2) at the same time as a charge transfer material because good characteristics are obtained.
[0046]
In addition to the above charge transfer materials, other charge transfer materials can be contained. Other charge transfer materials include polyvinyl carbazole, halogenated polyvinyl carbazole, polyvinyl pyrene, polyvinyl indoloquinoxaline, polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine, polyvinyl pyrazoline, polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylene vinylene, poly A conductive high molecular compound such as isothianaphthene, polyaniline, polydiacetylene, polyheptadiene, polypyridinediyl, polyquinoline, polyphenylene sulfide, polyferrosenylene, polyperinaphthylene, or polyphthalocyanine can be used. Further, as low molecular compounds, trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone, diphenoquinone, naphthoquinone, anthraquinone and derivatives thereof, anthracene, pyrene, polycyclic aromatic compounds such as phenanthrene, indole, carbazole, Nitrogen-containing heterocyclic compounds such as imidazole, fluorenone, fluorene, oxadiazole, oxazole, pyrazoline, hydrazone, triphenylmethane, triphenylamine, enamine, stilbene and the like can be used. Further, a polymer solid electrolyte in which a polymer compound such as polyethylene oxide, polypropylene oxide, polyacrylonitrile, and polymethacrylic acid is doped with a metal ion such as Li ion can also be used. Further, an organic charge transfer complex formed of an electron-donating compound and an electron-accepting compound represented by tetrathiafulvalene-tetracyanoquinodimethane can also be used. By mixing and adding the above compounds, desired photoreceptor characteristics can be obtained.
[0047]
An antioxidant, an ultraviolet absorber, a radical scavenger, a softening agent, a curing agent, a cross-linking agent, etc. are added to the coating solution for producing the electrophotographic photoreceptors 1 and 2 of the present invention as long as the properties are not impaired. Thus, the characteristics, durability, and mechanical characteristics of the photoreceptor can be improved. In particular, a phenolic antioxidant is useful because it contributes to improving the durability of the photoreceptor. Furthermore, by adding a dispersion stabilizer, an antisettling agent, a color separation inhibitor, a leveling agent, an antifoaming agent, a thickening agent, a matting agent, etc., the finished appearance of the photoreceptor and the life of the coating solution can be improved.
In addition, on the photosensitive layers 14 and 24, an organic thin film such as a polyvinyl formal resin, a polycarbonate resin, a fluorine resin, a polyurethane resin, or a silicone resin, or a siloxane structure formed of a hydrolyzate of a silane coupling agent is formed. A surface protective layer may be provided by forming a thin film, and in that case, the durability of the photoconductor is improved, which is preferable. This surface protective layer may be provided to improve functions other than the improvement of durability.
As the electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention, the charging method may be any of a contact type such as a brush and a roller, a non-contact type such as a scorotron and a corotron, and may be either positive or negative. It may be a charge. The exposure method may be any of LED, LD and the like. The developing system may be any of two-component, one-component, and magnetic / non-magnetic. The transfer system may be a roller, a belt, or the like.
[0048]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
[0049]
(Example 1)
Preparation of coating liquid
An alkyd resin and a melamine resin are mixed at a polymerization ratio of 6/4, titanium oxide is prepared at a weight ratio of 1/3 to the mixed resin, and dissolved and dispersed in methyl ethyl ketone to prepare a coating liquid for an undercoat layer. Next, a cylindrical substrate made of an aluminum alloy was dip-coated with the undercoat layer coating solution and dried at 130 ° C. for 20 minutes to form a 0.8 μm-thick undercoat layer.
Next, 10 g of β-type oxytitanium phthalocyanine powder showing the X-ray diffraction peak of FIG. 3 is put into a SUS pot together with glass beads, and dry-pulverized with a sand mill disperser for 40 hours to obtain amorphous oxytitanium phthalocyanine. Next, 500 ml was prepared at a ratio of 1,1,2-trichloroethane / dichloromethane / tetrahydrofuran = 7/2/1, and 5 g of polyvinyl butyral resin was dissolved therein. After milling for 30 minutes, the mixture was placed in the SUS pot and dispersed for 20 hours. The resulting dispersion was filtered to remove the glass beads to prepare a charge generation layer coating solution. This was applied by dip coating and dried to form a charge generation layer having a thickness of 0.2 μm.
Next, a polycarbonate resin as a binder resin, a butadiene compound represented by the formula (4) as a charge transfer material, and 2,6-di-tert-butyl-4-methyl-phenol as an antioxidant were added in a weight ratio. Prepared at 1.0: 1.0: 0.1 and dissolved in chloroform to prepare a coating solution for the charge transfer layer. The substrate on which the charge generation layer was formed was dip-coated with the coating solution for a charge transfer layer, and dried at 100 ° C. for 60 minutes to form a charge transfer layer having a thickness of 25.0 μm, thereby producing an electrophotographic photoreceptor.
[0050]
Preparation of sample sample for X-ray diffraction
A cut is made on the surface of the photoreceptor obtained in Example 1 in the circumferential direction and in the direction of the cylinder axis intersecting the same with an office cutter to form a cut having a side of about 2 cm. The photosensitive film is peeled off from the cut portion using tweezers. 15 ml of 4-methoxy-4-methylpentanone (PTX) is placed in a 50 ml beaker, and the release film is immersed in the beaker. After completely dissolving the charge transfer layer, the mixture is thoroughly stirred to form gel-like fine particles in the solvent. Disperse in. This is suction-filtered with a membrane filter (Pore size 0.2 μm) made of Teflon (registered trademark), and the filtrate is washed with 10 ml of PTX. Next, the membrane filter is adhered to the silicon anti-reflection plate so that the filtered material is on the inside, the membrane filter is peeled off only, oxytitanium phthalocyanine is attached to the silicon non-reflection plate, and it is air-dried and used as a sample sample for X-ray diffraction. did.
[0051]
X-ray diffraction
When measuring the specimen sample prepared as described above, it was measured by the thin film method, and CuKα (wavelength 1.54178 °) was used as the X-ray source, and the X-ray incident angle was 0.5 °. When measuring oxytitanium phthalocyanine powder, it was measured by a powder method, and CuKα (wavelength 1.54178 °) was used as an X-ray source. FIG. 4 shows an X-ray diffraction pattern of the sample. According to FIG. 4, oxytitanium phthalocyanine extracted from the photosensitive layer shows a characteristic diffraction peak at 7.5 °, and 9.4 °, 15.2 °, 22.6 °, 27.2 °, A diffraction peak is shown at 28.8 °. Furthermore, diffraction peaks are slightly observed at 13.2 °, 24.5 °, and 25.4 °. The peak intensity other than 7.5 ° is 20% or less of the peak intensity at 7.5 °.
[0052]
(Example 2)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1, except that the charge transport material represented by the formula (5) was used instead of the charge transport material used in Example 1.
[0053]
(Example 3)
Instead of the charge transfer material used in Example 1, a charge transfer material obtained by mixing a compound represented by the formula (5) and a compound represented by the formula (6) at a weight ratio of 3/7 was used. An electrophotographic photosensitive member was prepared in the same manner as in Example 1.
[0054]
(Example 4)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transport material represented by the formula (6) was used instead of the charge transport material used in Example 1.
[0055]
(Example 5)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transport material used in Example 1 was replaced with the charge transport material represented by the formula (7).
[0056]
(Example 6)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transport material represented by the formula (8) was used instead of the charge transport material used in Example 1.
[0057]
(Example 7)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1, except that the charge transport material used in Example 1 was replaced with the charge transport material represented by Formula (9).
[0058]
(Comparative Examples 1 to 3)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1, except that the charge transport material used in Example 1 was replaced with the charge transport material represented by Formulas (10) to (12). Each of the electrophotographic photosensitive members was set to Comparative Examples 1 to 3, respectively.
[0059]
Equation (10)
Embedded image

[0060]
Equation (11)
Embedded image

[0061]
Equation (12)
Embedded image

[0062]
(Comparative Example 4)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that oxytitanium phthalocyanine shown in FIG. 6 was used as the charge generating material instead of the charge generating material used in Example 1.
[0063]
(Comparative Example 5)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that oxytitanium phthalocyanine shown in FIG. 7 was used as the charge generating material instead of the charge generating material used in Example 1.
[0064]
(Comparative Example 6)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that oxytitanium phthalocyanine shown in FIG. 3 was used as the charge generating material instead of the charge generating material used in Example 1.
[0065]
Evaluation of electrophotographic photoreceptor 1
The electrophotographic photosensitive members obtained in Examples 1 to 7 and Comparative Examples 1 to 6 were mounted using a modified machine in which a surface electrometer was installed at the position of a developing unit of a Work Center 665 manufactured by XEROX.
As initial characteristics, the surface potential V0 of the photoreceptor after charging and the residual potential Ver when the surface potential was stabilized after exposure after charging and exposure of the photoreceptor were measured. The charged photosensitive drum is exposed to a laser beam having a wavelength of 780 nm, the amount of energy for attenuating the surface potential after exposure to 1/2 is measured, and E1 / 2 (μj / cm) ² ).
The above evaluation was performed in three environments: a measurement environment temperature of 25 ° C. and a humidity of 50% (N / N), a measurement environment temperature of 10 ° C. and a humidity of 20% (L / L), and a measurement environment temperature of 45 ° C. and a humidity of 50% (H / N). Was. Table 1 shows the results.
[0066]
Evaluation of electrophotographic photoreceptor 2
As 5K running characteristics, 5,000 sheets of A4 size paper were run, and the charged potential, residual potential, and half-life energy were measured in the same manner as in Evaluation 1 thereafter. The measurement was performed at a measurement environment temperature of 25 ° C. and a humidity of 50% (N / N). Table 1 shows the results.
[0067]
[Table 1]

[0068]
From Table 1, it can be seen that Examples 1 to 7 have a small half-reduction exposure amount and high sensitivity. In addition, it can be seen that there is almost no potential difference and half-life energy difference in the three environments, and it does not depend on the use environment. Furthermore, the difference in V0 before and after running 5,000 sheets is within 10 V, the difference in Ver is within 5 V, and there is almost a difference in half-life energy. The potential stability is extremely excellent in repeated use. You can see that. It can be seen that Comparative Examples 1 and 2 have a high Ver as a whole, and a large difference in Ver in the three environments. In addition, since the compatibility between the charge generation material and the charge transfer material is not very good, the half-life energy is higher than that of the example, and the difference in Ver before and after running is also large.
Comparative Example 3 also has a high Ver as a whole, and a large difference in Ver in the three environments. In addition, the difference between V0 and VL before and after running is large, and it can be seen that repetition stability is lacking.
Comparative Examples 4 and 5 have half energy energies equal to or greater than those of the Examples, but have a difference in V0 before and after running of about 30 to 40 V, lack potential stability during repetition, and meet high market demands. It cannot be answered.
Comparative Example 5 has a very high half-life energy and a large difference in VL before and after running.
[0069]
【The invention's effect】
As can be seen from the characteristic difference between the example and the comparative example, the electrophotographic photoreceptor of the present invention has high sensitivity due to low half-life energy, and shows a stable potential independent of the use environment. However, it shows the same characteristics as the initial stage, and can meet high market demands.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a laminated electrophotographic photosensitive member.
FIG. 2 is a cross-sectional view illustrating an example of a single-layer type electrophotographic photosensitive member.
FIG. 3 is an X-ray diffraction diagram of β-type oxytitanium phthalocyanine powder
FIG. 4 is an X-ray diffraction diagram of the phthalocyanine composition of the present invention.
FIG. 5 is an X-ray diffraction diagram of the phthalocyanine composition of the present invention.
FIG. 6 is an X-ray diffraction diagram of oxytitanium phthalocyanine used in Comparative Example 4.
FIG. 7 is an X-ray diffraction diagram of oxytitanium phthalocyanine used in Comparative Example 5.
[Explanation of symbols]
1,2 electrophotographic photoreceptor
11, 21 conductive substrate
12 charge generation layer
13 Charge transfer layer
14, 24 photosensitive layer

Claims (4)

An electrophotographic photosensitive member comprising a photosensitive layer containing at least a charge generation material, a charge transfer material, and a binder resin on a conductive support, wherein the charge generation material is oxytitanium phthalocyanine, and the oxytitanium The phthalocyanine has a maximum peak at a Bragg angle (2θ ± 0.2 °) of 7.5 ° in an X-ray diffraction spectrum using CuKα as a source, and the other diffraction peaks have a peak intensity of 7.5 °. An electrophotographic photoreceptor having a strength of 20% or less, and wherein the charge transfer material contains a compound represented by the general formula (1) and / or (2).
General formula (1)

(Wherein, R ₁ and R ₂ each independently represent an alkyl group having 1 to 6 carbon atoms which may have a substituent, and R ₃ represents a hydrogen atom or at least one alkyl group having 2 or more carbon atoms. Represents any one of the dialkylamino groups.)
General formula (2)

(Wherein, R _{4 to} R ₇ may be the same or different, and each independently has a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, or a substituent. R ₈ represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, an aryl group which may have a substituent, or a Represents an alkenyl group or an alkadienyl group, or general formula (3), and m represents an integer of 0 or 1.)
General formula (3)

(Wherein, R ₉ and R ₁₀ may be the same or different, and each independently has a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, or a substituent. Represents any of the aryl groups which may be present, and n represents an integer of 0 or 1.) 2. The electrophotographic photoreceptor according to claim 1, wherein the oxytitanium phthalocyanine has a Bragg angle (2θ ± 0.2 °) of 9.4 °, 15.2 °, 22.5 °, 27.2 °, 28.6 °. An electrophotographic photoreceptor characterized by having a diffraction peak. 2. The electrophotographic photoreceptor according to claim 1, wherein the oxytitanium phthalocyanine has a Bragg angle (2θ ± 0.2 °) of 9.4 °, 15.2 °, 22.5 °, 26.2 °, 27.2 °. An electrophotographic photosensitive member having a diffraction peak at 28.6 °. 2. The electrophotographic photoreceptor according to claim 1, wherein the oxytitanium phthalocyanine is dispersed in a photosensitive layer together with at least a binder resin, and the oxytitanium phthalocyanine is extracted from the photosensitive layer after the photosensitive layer is formed. In the X-ray diffraction spectrum, a Bragg angle (2θ ± 0.2 °) has a maximum peak at 7.5 °, and another diffraction peak intensity is 20% or less with respect to the diffraction peak intensity at 7.5 °. An electrophotographic photoreceptor having a strength of

Images