JP2005206507A - New amine-bisdiene and amine-bistriene-based compound, electrophotographic photoreceptor using them and image formation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electrophotographic photoreceptor that causes no partial crystallization damage during film formation or long-term preservation after making photoreceptor DR, has a high charging potential, a high sensitivity, sufficient photoresponsivity and durability, no deterioration in these properties even in the case of use in a low-temperature environment or in a high-speed process and high reliability and to provide an image formation apparatus. <P>SOLUTION: The electrophotographic photoreceptor comprises an organic photoconductive material composed of a new amine-bisdiene and/or amine-bistriene-based compound (meanings of symbols are omitted) having an asymmetric structure represented by general formula (1) as an electron transport substance in a photosensitive layer. The image formation apparatus is loaded with the electrophotographic photoreceptor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel amine-bisdiene and amine-bistriene compound having an asymmetric structure as a photoconductive material, and an electrophotographic photoreceptor and an image forming apparatus using the same.

  In recent years, organic photoconductive materials have been extensively researched and developed and used not only for electrophotographic photoreceptors (hereinafter also simply referred to as “photoreceptors”), but also for electrostatic recording elements, sensor materials or organic electroluminescent ( Electro Luminescent (abbreviation: EL) elements have begun to be applied. In addition, electrophotographic photoreceptors using organic photoconductive materials are used not only in the field of copying machines but also in fields such as printing plate materials, slide films, and microfilms in which photographic technology has been used. It is also applied to a high-speed printer using a laser, a light emitting diode (abbreviation: LED), or a cathode ray tube (abbreviation: CRT) as a light source. Therefore, the demand for organic photoconductive materials and electrophotographic photoreceptors using the same is becoming high and wide.

  Conventionally, as an electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer mainly composed of an inorganic photoconductive material such as selenium, zinc oxide or cadmium has been widely used. Although the inorganic photoreceptor has some basic characteristics as a photoreceptor, there are problems such as difficulty in forming a photosensitive layer, poor plasticity, and high manufacturing cost. Inorganic photoconductive materials are generally highly toxic and have significant limitations in manufacturing and handling.

On the other hand, an organic photoreceptor using an organic photoconductive material has good film-forming properties and excellent flexibility, and is lightweight and transparent. Since it has the advantage that a photoconductor showing good sensitivity in a wide wavelength range can be easily designed, it has been gradually developed as a mainstay of electrophotographic photoconductors. Early organic photoreceptors had drawbacks in sensitivity or durability, but these drawbacks were due to the development of a function-separated electrophotographic photoreceptor in which the charge generation function and the charge transport function were assigned to separate substances. It has been improved. The function-separated type photoconductor has advantages that the material selection range of the charge generation material responsible for the charge generation function and the charge transport material responsible for the charge transport function is wide, and an electrophotographic photoconductor having arbitrary characteristics can be produced relatively easily. Also have.
Examples of the charge generating material used in such a function-separated type photoreceptor include various types such as phthalocyanine pigments, squarylium dyes, azo pigments, perylene pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes and pyrylium salt dyes. Substances have been studied, and various materials having high light resistance and high charge generation ability have been proposed.

On the other hand, examples of the charge transport material include pyrazoline compounds (see, for example, Patent Document 1), hydrazone compounds (see, for example, Patent Document 2, Patent Document 3, and Patent Document 4), and triphenylamine compounds (for example, Patent Document 5). In addition, various compounds such as stilbene compounds (see, for example, Patent Document 7 and Patent Document 8) are known. The charge transport material is required to have the following characteristics (1) to (5). Although the charge transport material described above satisfies some of these characteristics, it has reached a high level of satisfaction. Not in.
(1) being stable to light and heat;
(2) being stable against ozone, nitrogen oxides (NO _x ), nitric acid, etc. generated by corona discharge when charging the surface of the photoreceptor;
(3) having a high charge transport capability;
(4) High compatibility with organic solvents and binders,
(5) Easy to manufacture and inexpensive.

  In addition, among the above-described characteristics, it is particularly required to have a high charge transport capability. For example, when a charge transport layer formed by dispersing a charge transport material together with a binder resin is the surface layer of the photoreceptor, the charge transport material is required to have a high charge transport capability in order to ensure sufficient photoresponsiveness. It is done. When the photoconductor is mounted and used in a copying machine or a laser beam printer, a part of the surface layer of the photoconductor is forced to be scraped off by a contact member such as a cleaning blade or a charging roller. In order to increase the durability of copying machines and laser beam printers, a surface layer that is strong against the contact members, that is, a surface layer with high printing durability that is hardly scraped off by the contact members is required.

  Therefore, if the content of the binder resin in the charge transport layer, which is the surface layer, is increased in order to strengthen the surface layer and improve the durability, the photoresponsiveness decreases. This is because the charge transporting ability of the charge transporting material is low, so the charge transporting material in the charge transporting layer is diluted with an increase in the binder resin content, and the charge transporting ability of the charge transporting layer is further reduced, resulting in photoresponse. It will be worse. If the photoresponsiveness is poor, the residual potential increases and the surface potential of the photoreceptor is repeatedly attenuated, so that the surface charge of the portion that should be erased by exposure is sufficiently erased. This will cause problems such as image quality deterioration at an early stage. Therefore, in order to ensure sufficient photoresponsiveness, the charge transport material is required to have a high charge transport capability.

In recent years, electrophotographic apparatuses such as digital copiers and printers have been miniaturized and speeded up, and there has been a demand for higher sensitivity corresponding to higher speeds as photoreceptor characteristics. The sensitivity is not lowered even when used in the above, and the change in characteristics is small and the reliability is high under various environments. As a charge transport material, a higher charge transport capability is required. Further, since the time from exposure to development is short in a high-speed process, a photoconductor with good photoresponsiveness is required. As described above, since the photoresponsiveness depends on the charge transporting ability of the charge transporting substance, a charge transporting substance having a higher charge transporting ability is required from this point.
As a charge transport material satisfying such requirements, a triarylamine-bisbutadiene compound having a widely conjugated system (see, for example, Patent Document 9 and Patent Document 10) has performance superior to that of the aforementioned charge transport material. It has been proposed as a compound. However, since these compounds are symmetrical compounds, they have poor solubility, and there are new problems such as partial crystallization during film formation or long-term storage as the photoreceptor DR.

Japanese Patent Publication No.52-4188 JP-A-54-50128 Japanese Patent Publication No.55-42380 JP-A-55-52063 Japanese Patent Publication No.58-32372 JP 54-151955 A JP 58-198043 A JP-A-2-190862 JP 7-173112 A JP-A-8-295655

  The object of the present invention is to cause no partial crystallization adverse effects during film formation or long-term storage as the photoreceptor DR, and has a high charging potential, high sensitivity, and sufficient photoresponsiveness. To develop a highly reliable electrophotographic photosensitive member and image forming apparatus that have high hole transport capability, high durability, and these characteristics do not deteriorate even when used in a low temperature environment or a high-speed process. is there.

As a result of diligent research to solve the above problems, the present inventors have found an amine-bisdiene or amine-bistriene compound having a novel asymmetric structure having excellent characteristics as an organic photoconductive material. An electrophotographic photosensitive member and an image forming apparatus having the above characteristics have been successfully obtained by including an organic photoconductive material comprising:
That is, the present invention provides an amine-bisdiene or amine-bistriene compound having a novel asymmetric structure represented by the following general formula (1), and a conductive support comprising a conductive material. And a photosensitive layer containing a charge generating material and a charge transport material provided on the conductive support, wherein the asymmetric structure represented by the following general formula (1) is used as the charge transport material: The present invention provides an electrophotographic photosensitive member containing an organic photoconductive material comprising an amine-bisdiene and / or an amine-bistriene-based compound, and an image forming apparatus equipped with such an electrophotographic photosensitive member.

（式中、Ａｒ^１及びＡｒ^４は、置換基を有してもよいアリール基もしくは複素環基を示す。Ａｒ^２及びＡｒ^３は、互いに異なって、置換基を有してもよいアリレン基もしくは２価の複素環基を示す。Ａｒ^５は、水素原子又は置換基を有してもよいアリール基、複素環基、アラルキル基もしくはアルキル基を示す。但し、Ａｒ^４及びＡｒ^５は、原子又は原子団を介して互いに結合し、環構造を形成してもよい。Ｒ^１、Ｒ^２及びＲ^３は、水素原子又は置換基を有してもよいアルキル基、アリール基、複素環基もしくはアラルキル基を示す。ｎは１〜２の整数を示し、ｎが２の場合、Ｒ^２及びＲ^３は同一でも異なってもよい。）

(In the formula, Ar ¹ and Ar ⁴ represent an aryl group or a heterocyclic group which may have a substituent. Ar ² and Ar ³ are different from each other, and an arylene group which may have a substituent or A divalent heterocyclic group, Ar ⁵ represents a hydrogen atom or an aryl group, heterocyclic group, aralkyl group or alkyl group which may have a substituent, provided that Ar ⁴ and Ar ⁵ are an atom or R ¹ , R ² and R ³ may be bonded to each other through an atomic group to form a ring structure, and R ¹ , R ² and R ³ may be a hydrogen atom or an alkyl group, aryl group, heterocyclic group or aralkyl which may have a substituent. And n represents an integer of 1 to 2, and when n is 2, R ² and R ³ may be the same or different.)

  According to the present invention, a novel amine-bisdiene or -bistriene compound having an asymmetric structure represented by the general formula (1) is contained as a charge transport material in the photosensitive layer as a charge transport material. Alternatively, there is no adverse effect of partial crystallization during long-term storage as the photoreceptor DR, the charging potential is high, the sensitivity is high, the photoresponsiveness is sufficient, and the high hole transport capability is a response. Since the content of the binder resin due to the property can be increased, a highly reliable electrophotographic photosensitive member that has high durability and does not deteriorate these characteristics even when used in a low-temperature environment or in a high-speed process can be obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 3 are schematic cross-sectional views of an electrophotographic photosensitive member that is an example of an embodiment of the present invention. FIG. 4 is a schematic view of an image forming apparatus provided with the electrophotographic photosensitive member according to the present invention. The electrophotographic photosensitive member and the image forming apparatus of the present invention are not limited to the forms shown in the drawings, and various modifications can be made without departing from the scope of the present invention.
In the electrophotographic photoreceptor of the present invention, an organic photoconductive material having a high hole transport ability resulting from an amine-bisdiene or -bistriene structure having an asymmetric structure represented by the following general formula (1) is used as a charge transport material. Thus, an extremely reliable electrophotographic photosensitive member having the above-described characteristics can be realized. Further, if the following organic photoconductive material is used for a sensor material, an EL element or an electrostatic recording element (including these widely as an electrophotographic photosensitive member), a device having excellent responsiveness can be provided.

上記一般式（１）において、Ａｒ^１及びＡｒ^４は、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複素環基を示す。その具体例としては、フェニル、トリル、メトキシフェニル、ナフチル及びビフェニリルなどのアリール基、フリル、チエニル、チアゾリル、ベンゾフリル及びベンゾチエニルなどの複素環基を挙げることができる。

In the general formula (1), Ar ¹ and Ar ⁴ represent an aryl group which may have a substituent or a heterocyclic group which may have a substituent. Specific examples thereof include aryl groups such as phenyl, tolyl, methoxyphenyl, naphthyl and biphenylyl, and heterocyclic groups such as furyl, thienyl, thiazolyl, benzofuryl and benzothienyl.

In the general formula (1), Ar ² and Ar ³ are different from each other and each represent an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent. Specific examples of Ar ³ include p-phenylene, 1,4-naphthylene, pyrenylene, and arylene groups such as 4,4′-biphenylene, 2,5-furylene, 2,5-thienylene, and 2,5-thiazolylene. The bivalent heterocyclic group of these can be mentioned.
In the general formula (1), Ar ⁵ represents an alkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent, or a substituent. An aralkyl group and a hydrogen atom that may be present are shown.
Specific examples other than the hydrogen atom of Ar ⁵ include alkyl groups such as methyl, ethyl, n-propyl, isopropyl and n-butyl, aryl groups such as phenyl, tolyl, methoxyphenyl, naphthyl and biphenyl, furyl, thienyl and thiazolyl. And heterocyclic groups such as benzofuryl and benzothienyl and aralkyl groups such as benzyl, p-methylbenzyl and p-methoxybenzyl.

In the general formula (1), R ¹ , R ² and R ³ are an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocycle which may have a substituent. An aralkyl group or a hydrogen atom which may have a ring group and a substituent is shown. Specific examples of hydrogen atoms other than R ¹ , R ² and R ³ include alkyl groups such as methyl, ethyl, n-propyl, isopropyl and n-butyl, aryl groups such as phenyl, tolyl, methoxyphenyl and naphthyl, furyl And heterocyclic groups such as thienyl and thiazolyl, and aralkyl groups such as benzyl and p-methoxybenzyl. Moreover, in General formula (1), n shows the integer of 1-2.

  The organic photoconductive material represented by the above general formula (1) has a high hole transport ability and has the following general formula (2) having a specific cyclic saturated structure and an amine-bisdiene structure having an asymmetric structure. By using a more specific compound represented by the formula (1) as a charge transport material, the production cost is relatively low, and there is a concern about the adverse effects of partial crystallization during film formation or during long-term storage as a photoreceptor DR. No charge, high charging potential, high sensitivity, sufficient photoresponsiveness, and high hole transport capability, so the binder resin content can be increased due to responsiveness, resulting in high durability and low temperature environment A highly reliable electrophotographic photosensitive member in which these characteristics do not deteriorate even when used in a lower or high-speed process can be obtained.

上記一般式（２）において、Ｚはベンゼン環と共に飽和の４〜８員環を形成するのに必要な水素、窒素、炭素、酸素、硫黄原子から構成される２価の原子団を示す。Ｚの具体例としては、下記表１のものを挙げることができる。

In the general formula (2), Z represents a divalent atomic group composed of hydrogen, nitrogen, carbon, oxygen, and sulfur atoms necessary for forming a saturated 4- to 8-membered ring together with the benzene ring. Specific examples of Z include those shown in Table 1 below.

In the general formula (2), a and b are each an alkyl group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, a perfluoroalkyl group having 1 to 5 carbon atoms, or 1 carbon atom. -3 alkoxy group, a C1-C8 dialkylamino group, a halogen atom or a hydrogen atom. Specific examples of a and b other than hydrogen atoms include alkyl groups such as methyl, ethyl, n-propyl and iso-propyl, monofluoromethyl, 1,1-bisfluoroethyl and 1,1,1-trisfluoro. Fluoroalkyl groups such as butyl, perfluoroalkyl groups such as trifluoromethyl, hexafluoroethyl and heptafluoropropyl, alkoxy groups such as methoxy, ethoxy, n-propoxy and iso-propoxy, dimethylamino, diethylamino and di-iso There may be mentioned dialkylamino groups such as -propylamino, and halogen atoms such as fluorine and chlorine. In the general formula (2), m represents an integer of 1 to 3, l represents an integer of 1 to 6, and two or more a and b are represented in the general formula (2). May be the same groups or different groups. Ar ² , Ar ⁴ and Ar ⁵ have the same meaning as defined in the general formula (1).

  The organic photoconductive material represented by the general formula (1) or (2) is an amine having an asymmetric structure in which a cyclic saturated 5-membered ring is introduced that is the simplest to introduce synthetically and has high reaction selectivity. By using a more specific compound represented by the following general formula (3) having a bisdiene structure as a charge transport material, the production cost is further reduced, and it is partially used at the time of film formation or long-term storage as a photoreceptor DR. Without worrying about the harmful effects of crystallization, the charging potential is high, the sensitivity is high, the photoresponsiveness is sufficient, and the high hole transport capability allows the binder resin content to be increased due to the responsiveness. Therefore, a highly reliable electrophotographic photosensitive member that has high durability and does not deteriorate these characteristics even when used in a low-temperature environment or in a high-speed process can be realized at low cost.

同一般式（３）中、Ｘ及びＹは、置換基を有してもよいメチレン基、置換基を有する窒素原子、酸素原子、硫黄原子を示す。Ｘ及びＹを含む飽和の５員環が結合したベンゼン環の具体例としては、前記表１に挙げたＺを含む飽和の４〜８員環が結合したベンゼン環の具体例中の５員環が結合したベンゼン環の化合物を挙げることができる。また、Ａｒ^２、Ａｒ^４、Ａｒ^５、ａ、ｂ、ｍ及びｌは前記一般式（２）において定義したものと同義である。

In the general formula (3), X and Y represent a methylene group which may have a substituent, a nitrogen atom having a substituent, an oxygen atom or a sulfur atom. Specific examples of the benzene ring bonded with a saturated 5-membered ring containing X and Y include the 5-membered rings in the specific examples of the benzene ring bonded with a saturated 4- to 8-membered ring containing Z listed in Table 1 above. And a compound having a benzene ring to which is bonded. Ar ² , Ar ⁴ , Ar ⁵ , a, b, m and l have the same meaning as defined in the general formula (2).

Further, among the organic photoconductive materials represented by the general formula (1), as a particularly excellent compound from the viewpoint of characteristics, cost, and productivity, Ar ¹ is saturated 4-containing z as shown in Table 1 above. Of the benzene ring structures to which 8-membered rings are bonded, those having the structures shown in Table 2 below are preferred, and specific examples thereof include Ar ² as a p-phenylene group, a methyl-p-phenylene group, and a methoxy-p-phenylene group. Group, or 4,4′-biphenylene group, Ar ³ is 1,4-naphthylene group, Ar ⁴ is phenyl, p-tolyl, p-methoxyphenyl group, Ar ⁵ is hydrogen atom, methyl, phenyl , P-tolyl group, R ¹ , R ² , R ³ , a and b are all hydrogen atoms, and n is 1.

Specific examples of the organic photoconductive material of the present invention represented by the general formula (1) include compounds having groups shown in Tables 3-1 to 5 below. The organic photoconductive material is not limited. Each group shown in the table corresponds to each group of the general formula (1).
For example, the exemplified compound No. 1 shown in Table 3-1. 1 is a compound represented by the following structural formula (1-1).

In the present invention, the amine-bisdiene or -bistriene compound having an asymmetric structure represented by the general formula (1) contained in the photosensitive layer is a novel compound and can be produced, for example, as follows.
First, a secondary amine and a halogenated aryl compound which may have a substituent, or a saturated 4- to 8-membered ring containing a carbon atom, a hydrogen atom, or a heteroatom such as an oxygen atom, a nitrogen atom or a sulfur atom is bonded. By subjecting the amine compound represented by the following general formula (4) obtained by condensation reaction with a halogenated benzene derivative to bisformylation by Vilsmeier reaction or bisacylation by Friedel-Craft reaction, An amine-biscarbonyl intermediate of formula (5) is prepared. At this time, by performing bisformylation by Vilsmeier reaction, among the amine-biscarbonyl intermediates represented by the following general formula (5), an amine-bisaldehyde intermediate in which R ¹ is a hydrogen atom can be produced. When bisacylation is carried out by Friedel-Craft reaction, among the amine-biscarbonyl intermediate represented by the following general formula (5), an amine-bisketo intermediate in which R ¹ is a group other than a hydrogen atom is produced. Can do.

（式中、Ａｒ^１、Ａｒ^２及びＡｒ^３は、前記一般式（１）において定義したものと同義である。）

(In the formula, Ar ¹ , Ar ² and Ar ³ have the same meaning as defined in the general formula (1).)

（式中、Ａｒ^１、Ａｒ^２、Ａｒ^３及びＲ^１は、前記一般式（１）において定義したものと同義である。）

(In the formula, Ar ¹ , Ar ² , Ar ³ and R ¹ have the same meaning as defined in the general formula (1).)

For example, the Vilsmeier reaction is performed as follows. In a solvent such as N, N-dimethylformamide (abbreviation: DMF), toluene or 1,2-dichloroethane, phosphorus oxychloride and N, N-dimethylformamide, phosphorus oxychloride and N-methyl-N-phenylformamide or oxy Phosphorus chloride and N, N-diphenylformamide are added to prepare Vilsmeier reagent. Add 1.0 equivalent of the amine intermediate represented by the general formula (4) to 2.0 to 2.2 equivalents of the prepared Vilsmeier reagent, and stir for 2 to 8 hours under heating at 80 to 100 ° C. . Then, it hydrolyzes with alkaline aqueous solution, such as 1-8N sodium hydroxide aqueous solution or potassium hydroxide aqueous solution. Thereby, among the amine-biscarbonyl intermediate represented by the general formula (5), an amine-bisaldehyde intermediate in which R ¹ is a hydrogen atom can be produced in a high yield.

Moreover, Friedel-Craft reaction is performed as follows, for example. Reagents prepared by aluminum chloride and acid chloride or acid anhydride in a solvent such as chloroform, 1,2-dichloroethane, nitrobenzene, and the like are represented by the above general formula (4). Add 1.0 equivalent of the amine intermediate and stir at −40-30 ° C. for 2-8 hours. At this time, heating is performed depending on circumstances. Then, it hydrolyzes with alkaline aqueous solution, such as 1-8N sodium hydroxide aqueous solution or potassium hydroxide aqueous solution. Thereby, among the amine-biscarbonyl intermediate represented by the general formula (5), an amine-bisketo intermediate in which R ¹ is a group other than a hydrogen atom can be produced in high yield.

  Next, the Wittig-Horner (Wittig-Horner) is prepared by reacting the amine-biscarbonyl intermediate represented by the general formula (5) with the Wittig reagent (Wittig reagent) represented by the following general formula (6) under basic conditions. ) A triarylamine-diene having an asymmetric structure in which the specific aryl group or cyclic saturated structure represented by the general formula (1), which is the organic photoconductive material of the present invention, is introduced by the reaction. -Triene compounds can be produced.

（式中、Ｒ^４は、置換基を有してもよいアルキル基又は置換基を有してもよいアリール基を示す。Ａｒ^４，Ａｒ^５，Ｒ^２，Ｒ^３及びｎは、前記一般式（１）において定義したものと同義である。）

(In the formula, R ⁴ represents an alkyl group which may have a substituent or an aryl group which may have a substituent. Ar ⁴ , Ar ⁵ , R ² , R ³ and n are the same as those in the general formula. (It is synonymous with what was defined in (1).)

  This Wittig-Horner reaction is performed, for example, as follows. 1. An amine-biscarbonyl intermediate represented by the general formula (5) in a solvent such as toluene, xylene, diethyl ether, tetrahydrofuran (abbreviation: THF), ethylene glycol dimethyl ether, N, N-dimethylformamide or dimethyl sulfoxide. 0 equivalent, 2.1 to 2.2 equivalent of the Wittig reagent represented by the general formula (6), and a metal alkoxide base such as potassium tert-butoxide, sodium ethoxide or sodium methoxide 2.2 to 2.4. And the mixture is stirred for 2 to 8 hours under heating at room temperature to 60 ° C. Thereby, the specific aryl group or cyclic saturated structure represented by the general formula (1) is introduced, and a triarylamine diene or -triene compound having an asymmetric structure can be produced in high yield.

  The electrophotographic photoreceptor according to the present invention (hereinafter also simply referred to as “photoreceptor”) is an organic photoconductive material of the present invention represented by the above general formula (1), for example, (2) and (3). There are various embodiments in which one or more materials are used as the charge transport material. FIG. 1 is a schematic cross-sectional view schematically showing an example of an electrophotographic photosensitive member according to the present invention. The electrophotographic photosensitive member 1 is charged on a sheet-like conductive support 11 made of a conductive material. The charge generation layer 15 containing the generation material 12 and the charge transport layer 16 containing the charge transport material 13 and the binder resin 17 that binds the charge transport material 13 are formed outwardly from the conductive support 11. It is a laminated type photoreceptor having a photosensitive layer 14 having a laminated structure that is laminated in order (in the drawing, the charge generating material 12 and the charge transporting material 13 are emphasized and depicted, but actually each layer is constituted, Alternatively, it is uniformly dispersed in a component such as a binder resin.)

  The charge transport layer 16 has, as the charge transport material 13, an amine-bisdiene or -bistriene having an asymmetric structure represented by the general formula (1), (2) or (3), which is the organic photoconductive material of the present invention. A compound is contained. Therefore, there is no partial crystallization adverse effect during film formation or long-term storage as the photoreceptor DR, high charging potential, high sensitivity, sufficient photoresponsiveness, and high hole transport capability. Highly reliable electrophotographic photosensitive member that has high durability because it can increase the content of binder resin due to its responsiveness, and does not deteriorate these characteristics even when used in a low-temperature environment or in a high-speed process Can be obtained. Further, as described above, the photosensitive layer 14 has a laminated structure of the charge generation layer 15 containing the charge generation material 12 and the charge transport layer 16 containing the charge transport material 13. In this way, by assigning the charge generation function and the charge transport function to separate layers, it becomes possible to select the most suitable material for each of the charge generation function and the charge transport function. It is possible to obtain an electrophotographic photosensitive member having high durability with increased stability during repeated use.

  As the conductive material constituting the conductive support 11, for example, a metal material such as aluminum, aluminum alloy, copper, zinc, stainless steel, or titanium can be used. Also, without being limited to these metal materials, polymer materials such as polyethylene terephthalate, nylon and polystyrene, those obtained by laminating metal foil on the surface of hard paper or glass, those obtained by vapor deposition of metal materials, or conductive high A layer obtained by vapor deposition or coating of a conductive compound such as a molecule, tin oxide, or indium oxide can also be used. The shape of the conductive support 11 is a sheet shape in the electrophotographic photosensitive member 1, but is not limited thereto, and may be a cylindrical shape, a columnar shape, an endless belt shape, or the like.

  If necessary, the surface of the conductive support 11 is irregularly reflected within a range that does not affect the image quality, such as anodic oxide film treatment, surface treatment with chemicals or hot water, coloring treatment, or surface roughening. Processing may be performed. In an electrophotographic process using a laser as an exposure light source, the wavelength of the laser beam is uniform, so that the incident laser beam and the light reflected in the electrophotographic photosensitive member cause interference, and interference fringes due to this interference appear on the image. May appear and cause image defects. By performing the above-described treatment on the surface of the conductive support 11, image defects due to interference of laser light having the same wavelength can be prevented.

  The charge generation layer 15 contains, as a main component, a charge generation material 12 that generates charges by absorbing light. Substances effective as the charge generation substance 12 include azo pigments such as monoazo pigments, bisazo pigments and trisazo pigments, indigo pigments such as indigo and thioindigo, perylene pigments such as peryleneimide and perylene anhydride, anthraquinone And polycyclic quinone pigments such as pyrenequinone, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, squarylium dyes, pyrylium salts and thiopyrylium salts, triphenylmethane dyes, and inorganic materials such as selenium and amorphous silicon Can be mentioned. These charge generation materials are used alone or in combination of two or more.

  Of these charge generation materials, oxotitanium phthalocyanine is preferably used. Since oxotitanium phthalocyanine is a charge generation material with high charge generation efficiency and charge injection efficiency, it generates a large amount of charge by absorbing light and transports the charge without accumulating the generated charge inside it. Efficient injection into the substance 13. Further, as described above, the charge transport material 13 is made of an organic photoconductive material having a high charge mobility represented by the general formula (1), (2) or (3). Therefore, the charge generated in the charge generation material 12 by light absorption is efficiently injected into the charge transport material 13 and smoothly transported, so that an electrophotographic photosensitive member with high sensitivity and high resolution can be obtained.

The charge generation material 12 includes triphenylmethane dyes represented by methyl violet, crystal violet, knight blue, and Victoria blue, erythrosine, rhodamine B, rhodamine 3R, acridine dyes represented by acridine orange, frappeosin, methylene blue, and the like. It may be used in combination with sensitizing dyes such as thiazine dyes typified by methylene green, oxazine dyes typified by capri blue and meldra blue, cyanine dyes, styryl dyes, pyrylium salt dyes or thiopyrylium salt dyes. Good.
As a method for forming the charge generation layer 15, a method in which the charge generation material 12 is vacuum-deposited on the conductive support 11, or a charge generation layer coating solution obtained by dispersing the charge generation material 12 in a solvent is made conductive. There is a method of coating on the support 11. Among these, the charge generating material 12 is dispersed by a conventionally known method in a binder resin solution obtained by dissolving a binder resin as a binder in a solvent, and the obtained coating solution is dispersed in the conductive support 11. The method of applying on top is preferred. Hereinafter, this method will be described.

  Examples of the binder resin include polyester resin, polystyrene resin, polyurethane resin, phenol resin, alkyd resin, melamine resin, epoxy resin, silicone resin, acrylic resin, methacrylic resin, polycarbonate resin, polyarylate resin, phenoxy resin, polyvinyl butyral resin, and the like. One type selected from the group consisting of resins such as polyvinyl formal resins and copolymer resins containing two or more of the repeating units constituting these resins is used alone or in combination of two or more types. The Specific examples of the copolymer resin include insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and acrylonitrile-styrene copolymer resin. be able to. The binder resin is not limited to these, and a commonly used resin can be used as the binder resin.

  Examples of the solvent include halogenated hydrocarbons such as dichloromethane and dichloroethane, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as tetrahydrofuran (THF) and dioxane, 1,2- Examples include alkyl ethers of ethylene glycol such as dimethoxyethane, aromatic hydrocarbons such as benzene, toluene and xylene, or aprotic polar solvents such as N, N-dimethylformamide and N, N-dimethylacetamide. Moreover, the mixed solvent which mixed 2 or more types of these solvents can also be used.

  The blending ratio of the charge generation material 12 and the binder resin is preferably such that the ratio of the charge generation material 12 is in the range of 10% by mass to 99% by mass. When the ratio of the charge generation material 12 is less than 10% by mass, the sensitivity is lowered. When the ratio of the charge generation material 12 exceeds 99% by mass, not only the film strength of the charge generation layer 15 decreases, but also the dispersibility of the charge generation material 12 decreases and coarse particles increase, which are erased by exposure. Since surface charges other than power are reduced, image defects, particularly image fogging called black spots, in which toner adheres to a white background and minute black spots are formed, increase. Therefore, it was set to 10 mass% to 99 mass%.

Prior to dispersing the charge generation material 12 in the binder resin solution, the charge generation material 12 may be pulverized by a pulverizer in advance. Examples of the pulverizer used for the pulverization treatment include a ball mill, a sand mill, an attritor, a vibration mill, and an ultrasonic disperser.
Examples of the disperser used when dispersing the charge generating substance 12 in the binder resin solution include a paint shaker, a ball mill, and a sand mill. As a dispersion condition at this time, an appropriate condition is selected so that impurities are not mixed due to wear of a container and a member constituting the disperser.

  Examples of the coating method for the coating solution for the charge generation layer obtained by dispersing the charge generation material 12 in the binder resin solution include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, and a dip coating method. be able to. Among these application methods, an optimum method can be selected in consideration of the physical properties and productivity of the application. In particular, the dip coating method is a method in which a layer is formed on the conductive support 11 by immersing the conductive support 11 in a coating tank filled with a coating solution and then pulling it up at a constant speed or a sequentially changing speed. Since it is relatively simple and excellent in terms of productivity and cost, it is widely used in the production of electrophotographic photosensitive members. In addition, you may provide the coating liquid dispersion | distribution apparatus represented by the ultrasonic generator in the apparatus used for the dip coating method in order to stabilize the dispersibility of a coating liquid.

The film thickness of the charge generation layer 15 is preferably 0.05 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 1 μm or less. When the film thickness of the charge generation layer 15 is less than 0.05 μm, the light absorption efficiency is lowered and the sensitivity is lowered. If the film thickness of the charge generation layer 15 exceeds 5 μm, the charge transfer inside the charge generation layer becomes a rate-limiting step in the process of erasing the charge on the surface of the photoreceptor, and the sensitivity is lowered. Therefore, the thickness is set to 0.05 μm or more and 5 μm or less.
The charge transport layer 16 is a charge transport material having the ability to transport the charge generated by the charge generation material 12 using the organic photoconductive material of the present invention represented by the general formula (1), (2) or (3). 13 to be contained in the binder resin 17. In the organic photoconductive material represented by the general formula (1), (2) or (3), one type selected from the group consisting of the exemplary compounds shown in Table 3 above is used alone, or two or more types are mixed. Have been used. The organic photoconductive material may be used as a mixture with other charge transport materials.

  Other charge transport materials include enamine derivatives, carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, hydrazone derivatives, many Ring aromatic compounds, indole derivatives, pyrazoline derivatives, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, triarylmethane derivatives, phenylenediamine derivatives, stilbene derivatives And benzidine derivatives. Also included are polymers having groups originating from these compounds in the main chain or side chain, such as poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9-vinylanthracene. However, in order to achieve a particularly high charge transport capability, the total amount of the charge transport material 13 is the organic photoconductive material of the present invention represented by the general formula (1), (2) or (3). Is preferred.

As the binder resin 17 used for the charge transport layer 16, a resin having excellent compatibility with the charge transport material 13 is selected. Specific examples include vinyl polymer resins such as polymethyl methacrylate resin, polystyrene resin, and polyvinyl chloride resin, and copolymer resins thereof, as well as polycarbonate resin, polyester resin, polyester carbonate resin, polysulfone resin, phenoxy resin, and epoxy. Examples thereof include resins such as resins, silicone resins, polyarylate resins, polyamide resins, polyether resins, polyurethane resins, polyacrylamide resins, and phenol resins. Moreover, you may use the thermosetting resin which bridge | crosslinked these resin partially. These resins may be used alone or in combination of two or more. Among the resins described above, polystyrene resin, polycarbonate resin, polyarylate resin, or polyphenylene oxide has a volume resistance value of 10 ¹³ Ω or more, excellent electrical insulation, and excellent film properties and potential characteristics. Therefore, it is particularly preferable to use these for the binder resin 17.

The ratio A / B between the charge transport material 13 (A) and the binder resin 17 (B) is generally about 10/12 in terms of mass ratio. However, in the electrophotographic photoreceptor 1 according to the present invention, the ratio A / B is 10/12 to 10/30.
As described above, since the charge transport material 13 includes the organic photoconductive material of the present invention having a high charge mobility represented by the general formulas (1), (2) and (3), the ratio A / B is Even when a binder resin is added at a ratio of 10/12 to 10/30 and a higher ratio than when a conventionally known charge transport material is used, the photoresponsiveness can be maintained. Therefore, the printing durability of the charge transport layer 16 can be improved and the durability of the electrophotographic photosensitive member can be improved without reducing the photoresponsiveness.

  When the ratio A / B is less than 10/30 and the ratio of the binder resin 17 is high, the viscosity of the coating liquid increases when the charge transport layer 16 is formed by the dip coating method, which causes a decrease in coating speed. Productivity is significantly degraded. Further, if the amount of the solvent in the coating solution is increased in order to suppress an increase in the viscosity of the coating solution, a brushing phenomenon occurs and white turbidity is generated in the formed charge transport layer 16. Further, when the ratio A / B exceeds 10/12 and the ratio of the binder resin 17 becomes low, the printing durability becomes lower than when the ratio of the binder resin 17 is high, and the wear amount of the photosensitive layer increases. Therefore, it was set to 10/12 or more and 10/30 or less.

  In order to improve the film formability, flexibility, and surface smoothness, an additive such as a plasticizer or a leveling agent may be added to the charge transport layer 16 as necessary. Examples of the plasticizer include dibasic acid esters, fatty acid esters, phosphate esters, phthalate esters, chlorinated paraffins, and epoxy type plasticizers. As a leveling agent, a silicone type leveling agent can be mentioned. The charge transport layer 16 may contain fine particles of an inorganic compound or an organic compound in order to increase mechanical strength and improve electrical characteristics. Furthermore, you may add various additives, such as antioxidant and a sensitizer, to the electric charge transport layer 16 as needed. As a result, the potential characteristics are improved, the stability as a coating solution is increased, fatigue deterioration when the photoreceptor is repeatedly used can be reduced, and durability can be improved.

  As the antioxidant, a hindered phenol derivative or a hindered amine derivative is preferably used. The hindered phenol derivative is preferably used in the range of 0.1 mass% or more and 50 mass% or less with respect to the charge transport material 13. The hindered amine derivative is preferably used in the range of 0.1 mass% or more and 50 mass% or less with respect to the charge transport material 13. A hindered phenol derivative and a hindered amine derivative may be mixed and used. In this case, the total use amount of the hindered phenol derivative and the hindered amine derivative is preferably in the range of 0.1 mass% or more and 50 mass% or less with respect to the charge transport material 13. When the amount of hindered phenol derivative used, the amount of hindered amine derivative used or the total amount of hindered phenol derivative and hindered amine derivative used is less than 0.1% by mass, the stability of the coating solution is improved and the durability of the photoreceptor is improved. A sufficient effect for improvement cannot be obtained. On the other hand, if it exceeds 50 mass%, the photoreceptor characteristics will be adversely affected. Therefore, the content is set to 0.1% by mass or more and 50% by mass or less.

  The charge transport layer 16 is formed by, for example, dissolving or dispersing the charge transport material 13 and the binder resin 17 and, if necessary, the aforementioned additives in an appropriate solvent, as in the case of forming the aforementioned charge generation layer 15. The charge transport layer coating solution is prepared, and this coating solution is applied onto the charge generation layer 15 by spraying, bar coating, roll coating, blade method, ring method or dip coating method. The Among these coating methods, the dip coating method is particularly excellent in various respects as described above, and is often used when the charge transport layer 16 is formed.

Solvents used in the coating solution include aromatic hydrocarbons such as benzene, toluene, xylene and monochlorobenzene, halogenated hydrocarbons such as dichloromethane and dichloroethane, ethers such as THF, dioxane and dimethoxymethyl ether, and N, N -1 type chosen from the group which consists of aprotic polar solvents, such as a dimethylformamide, is used individually or in mixture of 2 or more types. In addition, a solvent such as alcohols, acetonitrile, or methyl ethyl ketone can be further added to the above-described solvent as necessary.
The film thickness of the charge transport layer 16 is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 40 μm or less. When the film thickness of the charge transport layer 16 is less than 5 μm, the charge holding ability on the surface of the photoreceptor is lowered. When the film thickness of the charge transport layer 16 exceeds 50 μm, the resolution of the photoreceptor decreases. Accordingly, the thickness is set to 5 μm or more and 50 μm or less.

The photosensitive layer 14 may further contain one or more electron-accepting substances and dyes in order to improve sensitivity and suppress an increase in residual potential and fatigue during repeated use.
Examples of the electron acceptor include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride and 4-chloronaphthalic anhydride, cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, and 4-nitrobenzaldehyde. Aldehydes, anthraquinones such as anthraquinone and 1-nitroanthraquinone, polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone, and diphenoquinone compounds An electron-withdrawing material or a material obtained by polymerizing these electron-withdrawing materials can be used.
As the dye, for example, an organic photoconductive compound such as xanthene dye, thiazine dye, triphenylmethane dye, quinoline pigment or copper phthalocyanine can be used. These organic photoconductive compounds function as optical sensitizers.

A protective layer may be provided on the surface of the photosensitive layer 14. By providing the protective layer, the printing durability of the photosensitive layer 14 can be improved, and chemical adverse effects on the photosensitive layer 14 such as ozone and nitrogen oxides generated by corona discharge when charging the surface of the photoreceptor. Can be prevented. As the protective layer, for example, a layer made of a resin, an inorganic filler-containing resin, an inorganic oxide, or the like is used.
FIG. 2 is a schematic cross-sectional view showing a simplified configuration of an electrophotographic photosensitive member 2 which is another embodiment of the electrophotographic photosensitive member according to the present invention. The electrophotographic photosensitive member 2 is similar to the electrophotographic photosensitive member 1 shown in FIG. 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that an intermediate layer 18 is provided between the conductive support 11 and the photosensitive layer 14.

When there is no intermediate layer 18 between the conductive support 11 and the photosensitive layer 14, charges are injected from the conductive support 11 into the photosensitive layer 14, the chargeability of the photosensitive layer 14 is lowered, and it is erased by exposure. Surface charges other than those that should be reduced may cause defects such as fogging in the image. In particular, when an image is formed using a reversal development process, a toner image is formed in a portion where the surface charge has decreased due to exposure. Therefore, if the surface charge decreases due to factors other than exposure, the toner adheres to a white background. An image fogging called a black spot where minute black spots are formed occurs, and the image quality is significantly deteriorated.
That is, due to defects in the conductive support 11 or the photosensitive layer 14, the chargeability in a minute region is reduced, and fogging of an image such as black spots occurs, resulting in a significant image defect. By providing the intermediate layer 18 described above, injection of charges from the conductive support 11 to the photosensitive layer 14 can be prevented, so that the chargeability of the photosensitive layer 14 can be prevented from being lowered and erased by exposure. It is possible to suppress a decrease in surface charge other than that to be prevented, and to prevent occurrence of defects such as fogging on the image. In addition, by providing the intermediate layer 18, defects on the surface of the conductive support 11 can be covered to obtain a uniform surface, so that the film formability of the photosensitive layer 14 can be improved. Further, peeling of the photosensitive layer 14 from the conductive support 11 is suppressed, and adhesion between the conductive support 11 and the photosensitive layer 14 is improved.

  For the intermediate layer 18, a resin layer or an alumite layer made of various resin materials is used. The resin material that forms the resin layer includes polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, polyester resin, melamine resin, silicone resin, polyvinyl butyral resin, and polyamide. Examples thereof include resins such as resins, copolymer resins containing two or more of repeating units constituting these resins, casein, gelatin, polyvinyl alcohol, and ethyl cellulose. Among these, a polyamide resin is preferable, and an alcohol-soluble nylon resin is particularly preferable. Preferred alcohol-soluble nylon resins include, for example, so-called copolymer nylon obtained by copolymerizing 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 2-nylon, and the like, and N-alkoxymethyl-modified. Examples thereof include resins obtained by chemically modifying nylon such as nylon and N-alkoxyethyl-modified nylon.

The intermediate layer 18 may contain particles such as a metal oxide. By containing these particles, the volume resistance value of the intermediate layer 18 can be adjusted to further prevent the injection of charges from the conductive support 11 to the photosensitive layer 14, and the photosensitive member can be used in various environments. Electrical characteristics can be maintained.
Examples of metal oxide particles include particles of titanium oxide, aluminum oxide, aluminum hydroxide, tin oxide, and the like.
When particles such as metal oxide are included in the intermediate layer 18, for example, these particles are dispersed in a resin solution in which the above-described resin is dissolved to prepare a coating solution for the intermediate layer. The intermediate layer 18 can be formed by coating on the support 11.

Water or various organic solvents are used as the solvent of the resin solution. In particular, a single solvent such as water, methanol, ethanol or butanol or a mixture of water and alcohols, two or more alcohols, acetone or dioxolane and alcohols, chlorinated solvents such as dichloroethane, chloroform and trichloroethane, and alcohols. A solvent is preferably used.
As a method of dispersing the above-mentioned particles in the resin solution, a general method using a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser, or the like can be used.

The total content C of the resin and metal oxide in the intermediate layer coating solution is such that C / D is 1/99 to 40 / in mass ratio with respect to the content D of the solvent used in the intermediate layer coating solution. 60 is preferable, and 2/98 to 30/70 is more preferable. Further, the ratio of resin to metal oxide (resin / metal oxide) is preferably 90/10 to 1/99 by mass ratio, more preferably 70/30 to 5/95.
Examples of the coating method of the intermediate layer coating solution include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, and a dip coating method. In particular, as described above, the dip coating method is relatively simple and excellent in terms of productivity and cost. Therefore, the dip coating method is often used for forming the intermediate layer 18.

  The thickness of the intermediate layer 18 is preferably 0.01 μm or more and 20 μm or less, and more preferably 0.05 μm or more and 10 μm or less. If the thickness of the intermediate layer 18 is less than 0.01 μm, the intermediate layer 18 does not substantially function as the intermediate layer 18, and a uniform surface property cannot be obtained by covering defects of the conductive support 11. It becomes impossible to prevent the injection of charges from the body 11 to the photosensitive layer 14, and the chargeability of the photosensitive layer 14 is lowered. Making the thickness of the intermediate layer 18 greater than 20 μm makes it difficult to form the intermediate layer 18 when the intermediate layer 18 is formed by dip coating, and makes the photosensitive layer 14 uniformly on the intermediate layer 18. Since it cannot be formed and the sensitivity of the photoreceptor is lowered, it is not preferable.

FIG. 3 is a schematic cross-sectional view showing a simplified configuration of an electrophotographic photoreceptor 3 that is still another embodiment of the present invention. The electrophotographic photosensitive member 3 is similar to the electrophotographic photosensitive member 2 shown in FIG. 2, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.
It should be noted that the electrophotographic photosensitive member 3 is a single layer type photosensitive member having a photosensitive layer 14 having a single layer structure in which both the charge generation material 12 and the charge transport material 13 are contained in the binder resin 17. That is.
The photosensitive layer 14 is formed by the same method as that for forming the charge transport layer 13 described above. For example, the charge generating material 12 described above, the charge transporting material 13 containing the organic photoconductive material of the present invention represented by the general formula (1), (2) or (3) and the binder resin 17 are combined with the above-mentioned appropriate one. A photosensitive layer coating solution is prepared by dissolving or dispersing in a suitable solvent, and this photosensitive layer coating solution is applied onto the intermediate layer 18 by a dip coating method or the like.

The ratio of the charge transport material 13 and the binder resin 17 in the photosensitive layer 14 is 10/12 in mass ratio, similar to the ratio A / B of the charge transport material 13 and the binder resin 17 in the charge transport layer 16 described above. -10/30.
The film thickness of the photosensitive layer 14 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less. If the film thickness of the photosensitive layer 140 is less than 5 μm, the charge holding ability on the surface of the photoreceptor is lowered. When the film thickness of the photosensitive layer 140 exceeds 100 μm, the productivity is lowered. Accordingly, the thickness is set to 5 μm or more and 100 μm or less.
The electrophotographic photosensitive member according to the present invention is not limited to the configuration shown in FIGS. 1 to 3 described above, and can adopt various layer configurations.

Moreover, you may add various additives, such as antioxidant, a sensitizer, and a ultraviolet absorber, to each layer of a photoreceptor as needed. As a result, the potential characteristics can be improved. Further, the stability of the coating solution when forming a layer by coating is increased. Further, it is possible to reduce fatigue deterioration and improve durability when the photoreceptor is used repeatedly.
In particular, examples of the antioxidant include phenolic compounds, hydroquinone compounds, tocopherol compounds, and amine compounds. These antioxidants are preferably used in the range of 0.1 mass% to 50 mass% with respect to the charge transport material 13. When the amount of the antioxidant used is less than 0.1% by mass, it is not possible to obtain a sufficient effect for improving the stability of the coating solution and improving the durability of the photoreceptor. When the amount of the antioxidant used exceeds 50% by mass, the photoreceptor characteristics are adversely affected. Therefore, the content is set to 0.1% by mass or more and 50% by mass or less.

Next, an image forming apparatus including the electrophotographic photosensitive member according to the present invention will be described. The image forming apparatus according to the present invention is not limited to the following description.
FIG. 4 is a configuration diagram showing a simplified configuration of an image forming apparatus including the electrophotographic photosensitive member according to the present invention.
As shown in the figure, the image forming apparatus 5 includes an electrophotographic photosensitive member 10 (hereinafter, also simply referred to as “photosensitive member 10”) according to the present invention. The photosensitive member 10 has a cylindrical shape and is rotationally driven at a predetermined peripheral speed in the direction of reference numeral 41 by a driving unit (not shown). A charger 32, a semiconductor laser (not shown), a developing device 33, a transfer charger 34, and a cleaner 36 are provided in this order around the photoconductor 10 along the rotation direction of the photoconductor 10. A fixing device 35 is provided in the traveling direction of the transfer paper 51.

  An image forming process by the image forming apparatus 5 will be described. First, the photoreceptor 10 is uniformly charged with a predetermined positive or negative potential on a surface 43 facing the charger 32 by a contact-type or non-contact-type charger 32. Next, a laser beam 31 is irradiated from a semiconductor laser (not shown), and the surface 43 of the photoreceptor 10 is exposed. The laser beam 31 is repeatedly scanned in the longitudinal direction of the photoconductor 10 which is the main scanning direction, and accordingly, electrostatic latent images are sequentially formed on the surface 43 of the photoconductor 10. The electrostatic latent image is developed as a toner image by a developing device 33 provided on the downstream side in the rotation direction from the image forming point of the laser beam 31.

In synchronism with the exposure of the photosensitive member 10, the transfer paper 51 is fed from the direction of the reference symbol 42 to the transfer charger 34 provided on the downstream side in the rotation direction of the developing device 33.
The toner image formed on the surface 43 of the photoconductor 10 in the developing device 33 is transferred onto the surface of the transfer paper 51 by the transfer charger 34. The transfer paper 51 onto which the toner image has been transferred is transported to the fixing device 35 by a transport belt (not shown), and the toner image is fixed to the transfer paper 51 by the fixing device 35 to form a part of the image.
The toner remaining on the surface 43 of the photoconductor 10 is removed by a cleaner 36 provided with a charge eliminating lamp (not shown) further downstream in the rotation direction of the transfer charger 34 and upstream in the rotation direction of the charger 32. By further rotating the photoreceptor 10, the above process is repeated and an image is formed on the transfer paper 51. The transfer paper 51 on which the image is formed in this manner is discharged outside the image forming apparatus 5.

As described above, the electrophotographic photoreceptor 10 provided in the image forming apparatus 5 uses the organic photoconductive material of the present invention represented by the general formula (1), for example, (2) or (3), as a charge transport material. Therefore, the charging potential is high, the sensitivity is high, the photoresponsiveness is sufficient, the durability is excellent, and the characteristics are not deteriorated even when used in a low temperature environment or in a high-speed process.
Therefore, it is possible to obtain a highly reliable image forming apparatus capable of providing high quality images under various environments. In addition, since the electrophotographic photosensitive member 10 does not deteriorate in performance due to light exposure, the deterioration of image quality due to exposure of the photosensitive member to light during maintenance or the like is prevented, and the reliability of the image forming apparatus is improved. Can do.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
Production Example 1 Exemplified Compound No. 1 (Table 3-1) (Production Example 1-1) Production of amine-bisaldehyde intermediate In 100 ml of anhydrous N, N-dimethylformamide (DMF), 18.4 g (2 .4 equivalents) was gradually added and stirred for about 30 minutes to prepare Vilsmeier reagent. To this solution, 16.9 g (1.0 equivalent) of a triarylamine intermediate represented by the following structural formula (7) was gradually added under ice cooling. Then, it heated gradually, raised reaction temperature to 110 degreeC, and stirred for 3 hours, heating so that 110 degreeC might be maintained. After completion of the reaction, the reaction solution was allowed to cool and gradually added to 800 ml of a cooled 4N (4N) sodium hydroxide aqueous solution to cause precipitation. The resulting precipitate was filtered off, washed thoroughly with water, and then recrystallized with a mixed solvent of ethanol and ethyl acetate to obtain 17.4 g of a yellow powdery compound.
As a result of analyzing the obtained compound by LC-MS, a molecular ion [M + H] in which a proton was added to a triarylamine-bisaldehyde intermediate (calculated molecular weight: 395.12) represented by the following structural formula (8): ^Since a peak corresponding to ⁺ was observed at 396.4, it was found that the obtained compound was a triarylamine-bisaldehyde intermediate represented by the following structural formula (8) (yield: 88% ). Moreover, the analysis result of LC-MS showed that the purity of the obtained triarylamine-bisaldehyde intermediate was 99.0%.

以上のように、前記構造式（７）で示されるトリアリールアミン中間体に対して、ビルスマイヤー反応によるビスフォルミル化を行うことによって、前記構造式（８）で示されるトリアリールアミン−ビスアルデヒド中間体を得ることができた。

As described above, by performing bisformylation by the Vilsmeier reaction on the triarylamine intermediate represented by the structural formula (7), the triarylamine-bisaldehyde intermediate represented by the structural formula (8) is obtained. I was able to get a body.

(Production Example 1-2)
7.90 g (1.0 equivalent) of the triarylamine-bisaldehyde intermediate represented by the structural formula (8) obtained in Production Example 1-1 and diethylcinnamyl phosphonate represented by the following structural formula (9) 12.2 g (2.4 equivalents) was dissolved in 80 ml of anhydrous DMF, and 5.6 g (3.5 equivalents) of potassium tert-butoxide was gradually added to the solution at 0 ° C., and then at room temperature for 1 hour. The mixture was allowed to stand, further heated to 50 ° C., and stirred for 5 hours while heating to maintain 50 ° C. The reaction mixture was allowed to cool and then poured into excess methanol. The precipitate was collected and dissolved in toluene to obtain a toluene solution. The toluene solution was transferred to a separatory funnel and washed with water. Then, the organic layer was taken out, and the taken out organic layer was dried over magnesium sulfate. After drying, the organic layer from which the solid was removed was concentrated and subjected to silica gel column chromatography to obtain 10.9 g of yellow crystals.

The obtained crystals were analyzed by LC-MS. A peak corresponding to the molecular ion [M + H] ⁺ in which a proton was added to one exemplary compound (calculated molecular weight: 595.25) was observed at 596.7.
From the analysis results of LC-MS, the obtained crystals were obtained from Exemplified Compound No. 1 (yield: 92%). LC-MS analysis results showed that the purity was 99.3%.
As described above, the Wittig-Horner reaction between the triarylamine-bisaldehyde intermediate represented by the structural formula (8) and the diethylcinnamylphosphonate represented by the structural formula (9) which is a Wittig reagent is performed. By way of example compound No. shown in Table 3-1. 1 could be obtained.

(Production Example 2) Exemplified Compound No. 46 (Table 3-3) 1.80 g (1.0 equivalent) of the triarylamine-bisaldehyde intermediate represented by the structural formula (8) obtained in Production Example 1-1 and the following structural formula ( 10) Wittig reagent 3.06 g (2.4 equivalents) was dissolved in anhydrous DMF 15 ml, and potassium t-butoxide 1.42 g (2.5 equivalents) was gradually added to the solution at 0 ° C. Thereafter, the mixture was allowed to stand at room temperature for 1 hour, further heated to 50 ° C., and stirred for 5 hours while heating to maintain 50 ° C. The reaction mixture was allowed to cool and then poured into excess methanol. The precipitate was collected and dissolved in toluene to obtain a toluene solution. The toluene solution was transferred to a separatory funnel and washed with water. Then, the organic layer was taken out, and the taken out organic layer was dried over magnesium sulfate. After drying, the organic layer from which the solid was removed was concentrated and subjected to silica gel column chromatography to obtain 2.38 g of yellow crystals.

As a result of analyzing the obtained crystals by LC-MS, the target compound Nos. Shown in Table 3-3 were obtained. Since a peak corresponding to a molecular ion [M + H] ⁺ in which a proton was added to 46 compound (calculated molecular weight: 647.28) was observed at 648.5, the obtained crystal was exemplified by Compound No. 1. 46 (yield: 81%). In addition, from the results of LC-MS analysis, the obtained Exemplified Compound Nos. The purity of 46 was found to be 99.7%.
As described above, by performing the Wittig-Horner reaction between the triarylamine-bisaldehyde intermediate represented by the structural formula (8) and the Wittig reagent represented by the structural formula (10), Table 3-3 Illustrative compound No. shown 46 could be obtained.

[Example 1]
1 part by mass of an azo compound represented by the following structural formula (11) as the charge generation material 12 was added to a resin solution obtained by dissolving 1 part by mass of a phenoxy resin (manufactured by Union Carbide: PKHH) in 99 parts by mass of THF. Thereafter, the mixture was dispersed for 2 hours with a paint shaker to prepare a coating solution for a charge generation layer. This coating solution for charge generation layer was applied to a conductive support 11 on a 80 μm thick polyester film with aluminum deposited on the surface using a bakery applicator and then dried to obtain a film thickness of 0. A charge generation layer 15 having a thickness of 3 μm was formed.

Next, exemplary compound No. 1 shown in Table 3-1 which is the charge transport material 13 was used. 1 specific aryl group or cyclic saturated structure is introduced, and 8 parts by mass of a triarylamine-diene compound having an asymmetric structure and a polycarbonate resin (Teijin Kasei Co., Ltd .: C-1400) 10 as a binder resin 17 Part by mass was dissolved in 80 parts by mass of THF to prepare a charge transport layer coating solution. This coating solution for charge transport layer was applied on the charge generation layer 15 previously formed by a baker applicator and then dried to form a charge transport layer 16 having a thickness of 10 μm.
As described above, a laminated electrophotographic photosensitive member having the structure shown in FIG. 1 was produced.

[Examples 2 to 4]
For the charge transport material 13, the exemplified compound No. In place of Exemplified Compound No. 1 3 types in the same manner as in Example 1 except that an amine-bisdiene or -bistriene compound having an asymmetric structure of 15 (Table 3-1), 30 (Table 3-2) or 69 (Table 3-4) is used. An electrophotographic photoreceptor was prepared.

[Comparative Example 1]
For the charge transport material 13, the exemplified compound No. Instead of 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the comparative compound A represented by the following structural formula (12) was used.

[Comparative Example 2]
For the charge transport material 13, the exemplified compound No. Instead of 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the comparative compound B represented by the following structural formula (13) was used.

[Comparative Example 3]
For the charge transport material 13, the exemplified compound No. Instead of 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the comparative compound B represented by the following structural formula (14) was used. However, in this sample, after film formation / drying, innumerable microcrystals were generated on the sheet surface due to the poor compatibility of the comparative compound C, and the mobility could not be measured.

[Comparative Example 4]
For the charge transport material 13, the exemplified compound No. Instead of 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the comparative compound B represented by the following structural formula (15) was used.

[Evaluation 1]
For each of the electrophotographic photoreceptors prepared in Examples 1 to 4 and Comparative Examples 1 to 4, gold was deposited on the surface of the photosensitive layer of each electrophotographic photoreceptor, and the flight time (Time- The charge mobility of the charge transport material 13 was measured by the of-Flight method. Table 4 shows the measurement results. In addition, the value of the charge mobility shown in Table 4 is a value when the electric field strength is 2.5 × 10 ⁵ V / cm.

  From comparison between Examples 1 to 4 and Comparative Examples 1 to 4, the organic photoconductive material of the present invention represented by the general formula (1) is triphenyl such as comparative compound A which is a conventionally known charge transport material. Compared to amine dimer (abbreviation: TPD), triphenylamine-stilbene comparative compound B having a specific cyclic saturated structure introduced, triarylamine-bisstilbene, etc. It was.

[Example 5]
9 parts by mass of resinous titanium oxide (Ishihara Sangyo Co., Ltd .: TTO-D-1) surface-treated with aluminum oxide (Al ₂ O ₃ ) and zirconium dioxide (ZrO ₂ ) and copolymer nylon resin (Toray Industries, Inc.) 9 parts by mass of CM8000 manufactured by Co., Ltd. is added to a mixed solvent of 41 parts by mass of 1,3-dioxolane and 41 parts by mass of methanol, and dispersed for 12 hours using a paint shaker to prepare an intermediate layer coating solution. did. The prepared coating solution for intermediate layer was applied on a 0.2 mm-thick aluminum substrate as the conductive support 11 with a bakery applicator and then dried to form an intermediate layer 18 having a thickness of 1 μm.
Next, 2 parts by mass of the azo compound represented by the following structural formula (16), which is the charge generation material 12, is dissolved in 1 part by mass of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: BX-1) in 97 parts by mass of THF. After being added to the resin solution obtained above, it was dispersed with a paint shaker for 10 hours to prepare a coating solution for charge generation layer. This charge generation layer coating solution was applied onto the previously formed intermediate layer 18 with a baker applicator and then dried to form a charge generation layer 15 having a thickness of 0.3 μm.

Subsequently, Exemplified Compound No. 1 which is the charge transport material 13 10 parts by mass of a triarylamine-diene compound having a specific aryl group into which a specific cyclic saturated structure is introduced or a cyclic saturated structure is introduced and having an asymmetric structure, and a polycarbonate resin (Mitsubishi Gas Chemical) Co., Ltd .: Z200) 14 parts by mass and 0.26 parts by mass of 2,6-di-t-butyl-4-methylphenol were dissolved in 80 parts by mass of THF to prepare a coating solution for a charge transport layer. . This coating solution for charge transport layer was applied on the charge generation layer 15 previously formed by a baker applicator and then dried to form a charge transport layer 16 having a thickness of 18 μm.
As described above, a multilayer electrophotographic photosensitive member having the configuration shown in FIG. 2 was produced.

[Examples 6 to 8]
For the charge transport material 13, the exemplified compound No. In place of Exemplified Compound No. 1 Three types of electrophotographic photosensitive members were produced in the same manner as in Example 5 except that an amine-bisdiene or -bistriene compound having an asymmetric structure of 23, 36 or 69 was used.

[Comparative Examples 5 to 7]
For the charge transport material 13, the exemplified compound No. Example 1 except that Comparative Compound A represented by Structural Formula (12), Comparative Compound B represented by Structural Formula (13) or Comparative Compound D represented by Structural Formula (15) was used instead of 1. In the same manner as in Example 5, three types of electrophotographic photoreceptors were produced.

[Example 9]
In the same manner as in Example 5, a coating solution for an intermediate layer was prepared, and this was applied onto an aluminum substrate having a thickness of 0.2 mm, which is the conductive support 11, and then dried to form an intermediate layer 18 having a thickness of 1 μm. Formed.
Next, 1 part by mass of the azo compound represented by the structural formula (16) as the charge generation material 12, 12 parts by mass of the polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc .: Z-400) as the binder resin 17, charge transport Exemplified Compound No. 1 as Substance 13 10 parts by weight of a triphenylamine-butadiene compound into which one specific cyclic saturated structure is introduced, 5 parts by weight of 3,5-dimethyl-3 ′, 5′-di-t-butyldiphenoquinone, 2,6-di 0.5 parts by mass of t-butyl-4-methylphenol and 65 parts by mass of THF were dispersed with a ball mill for 12 hours to prepare a coating solution for a photosensitive layer. The prepared photosensitive layer coating solution is applied onto the previously formed intermediate layer 18 by a bakery applicator and then dried with hot air at 110 ° C. for 1 hour to form a photosensitive layer 14 having a thickness of 20 μm shown in FIG. did.
As described above, a single-layer electrophotographic photosensitive member having the configuration shown in FIG. 3 was produced.

[Example 10]
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that X-type metal-free phthalocyanine was used as the charge generation material 12 in place of the azo compound represented by the structural formula (16).

[Examples 11 to 13]
Instead of the azo compound represented by the structural formula (16), an X-type metal-free phthalocyanine is used as the charge generation material 12, and the exemplified compound No. 1 is used as the charge transport material 13. In place of Exemplified Compound No. 1 Three types of electrophotographic photosensitive members were produced in the same manner as in Example 5 except that an amine-bisdiene or -bistriene compound having an asymmetric structure of 2, 30 or 46 was used.

[Comparative Examples 8 to 10]
Instead of the azo compound represented by the structural formula (16), an X-type metal-free phthalocyanine is used as the charge generation material 12, and the exemplified compound No. 1 is used as the charge transport material 13. Example 1 except that Comparative Compound A represented by Structural Formula (12), Comparative Compound B represented by Structural Formula (13) or Comparative Compound D represented by Structural Formula (15) was used instead of 1. In the same manner as in Example 5, three types of electrophotographic photoreceptors were produced.

[Evaluation 2]
About each electrophotographic photoreceptor produced in the above Examples 5 to 13 and Comparative Examples 5 to 10, initial characteristics and repetitive characteristics using an electrostatic copying paper test apparatus (manufactured by Kawaguchi Electric Manufacturing Co., Ltd .: EPA-8200). Evaluated. The evaluation of the initial characteristics and the repetitive characteristics is as follows: room temperature / normal humidity environment (hereinafter referred to as N / N environment) at a temperature of 22 ° C. and a relative humidity of 65% (22 ° C./65% RH). The temperature was 5 ° C. and the relative humidity was 20% (5 ° C./20% RH) in a low temperature / low humidity environment (hereinafter referred to as an L / L environment).
The initial characteristics were evaluated as follows. The surface of the photoconductor was charged by applying a negative (−) 5 kV voltage to the photoconductor, and the surface potential of the photoconductor at this time was measured as a charging potential V ₀ (V). However, in the case of the single layer type photoreceptor of Example 9, a voltage of plus (+) 5 kV was applied. Next, the charged photoreceptor surface was exposed. At this time, the energy required to halve the surface potential of the photosensitive member from the charging potential V ₀ was measured as a half exposure amount E _1/2 (μJ / cm ² ) and used as an evaluation index for sensitivity. Further, the surface potential of the photosensitive member at the time when 10 seconds had elapsed from the start of exposure was measured as a residual potential V _r (V), which was used as an evaluation index of photoresponsiveness. In the exposure, in the case of the photoreceptors of Examples 5 to 9 and Comparative Examples 5, 6, and 7 in which the azo compound represented by the structural formula (13) is used as the charge generation material 12, the exposure energy is 1 μW / In the case of the photoconductors of Examples 10 to 13 and Comparative Examples 8, 9, and 10 using white light of cm ² and using X-type metal-free phthalocyanine, the wavelength obtained by spectroscopy with a monochromator is 780 nm, exposure Light having an energy of 1 μW / cm ² was used.
Evaluation of repetitive characteristics was performed as follows. After the above-described charging and exposure operations were repeated 5000 times as one cycle, the half-exposure amount E _1/2 , the charging potential V ₀ and the residual potential V _r were measured in the same manner as the evaluation of the initial characteristics.
The above measurement results are shown in Table 5.

From the comparison between Examples 5 to 8 and Comparative Examples 5, 6, and 7 and the comparison between Examples 10 to 13 and Comparative Examples 8, 9, and 10, the charge transport material 13 is represented by the general formula (1). The photoconductors of Examples 5 to 8 and 10 to 13 using the organic photoconductive material of the invention are more preferable than the photoconductors of Comparative Examples 5 to 10 using the comparative compound A, B, or D as the charge transport material 13. However, it was found that the half-exposure amount E _1/2 was small and the sensitivity was high, the residual potential V _r was low in the negative direction, that is, the potential difference between the residual potential V _r and the reference potential was small, and the photoresponsiveness was excellent. It was also found that this characteristic is maintained even when used repeatedly, and also maintained in a low temperature / low humidity (L / L) environment.

[Example 14]
9 parts by mass of dendritic titanium oxide (Itohara Sangyo Co., Ltd .: TTO-D-1) surface-treated with aluminum oxide (Al ₂ O ₃ ) and zirconium dioxide (ZrO ₂ ) and copolymer nylon resin (Toray Industries, Inc.) After adding 9 parts by mass of CM8000, a mixed solvent of 41 parts by mass of 1,3-dioxolane and 41 parts by mass of methanol, dispersion treatment was performed with a paint shaker for 8 hours, Prepared. This intermediate layer coating solution is filled in the coating tank, and the cylindrical conductive support 11 made of aluminum having a diameter of 40 mm and a total length of 340 mm is immersed in the coating tank and then pulled up, whereby the intermediate layer 18 having a film thickness of 1.0 μm is obtained. Was formed on the conductive support 11.
Next, as an oxotitanium phthalocyanine which is the charge generation material 12, a diffraction peak is observed at least at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray (wavelength: 1 to 54Å). 2 parts by mass of oxotitanium phthalocyanine having the crystal structure shown, 1 part by mass of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: ESREC BM-S) and 97 parts by mass of methyl ethyl ketone are mixed and dispersed in a paint shaker It processed and the coating liquid for charge generation layers was prepared. By applying this coating solution for charge generation layer on the intermediate layer 18 formed in the same manner as the intermediate layer 18 formed earlier, that is, by dip coating, a charge generation with a film thickness of 0.4 μm is generated. Layer 15 was formed on intermediate layer 18.
Subsequently, Exemplified Compound No. 1 which is the charge transport material 13 10 parts by mass of a triarylamine-diene compound having a specific aryl group or cyclic saturated structure and an asymmetric structure, and polycarbonate resin (manufactured by Mitsubishi EP Co., Ltd .: Iupilon Z200) ) 20 parts by mass, 1 part by mass of 2,6-di-t-butyl-4-methylphenol and 0.004 part by mass of dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd .: KF-96) A charge transport layer coating solution was prepared by dissolving in 110 parts by mass. The charge transport layer coating solution is applied onto the charge generation layer 15 formed earlier by the same dip coating method as that for the intermediate layer 18 formed earlier, and then dried at 110 ° C. for 1 hour. A 23 μm charge transport layer 16 was formed.
An electrophotographic photosensitive member was produced as described above.

[Examples 15 to 16]
For the charge transport material 13, the exemplified compound No. In place of Exemplified Compound No. 1 Two types of electrophotographic photosensitive members were used in the same manner as in Example 14 except that a triarylamine-diene or -triene compound having an asymmetric structure in which 2 or 69 specific aryl groups or cyclic saturated structures were introduced was used. Was made.

[Comparative Example 11]
For the charge transport material 13, the exemplified compound No. Instead of 1, an electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the comparative compound A represented by the structural formula (12) was used.

[Example 17]
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the amount of the polycarbonate resin as the binder resin 17 of the charge transport layer 16 was 25 parts by mass.

[Examples 18 and 19]
The amount of the polycarbonate resin that is the binder resin 17 of the charge transport layer 16 is 25 parts by mass. In place of Exemplified Compound No. 1 shown in Table 3 Two types of electrophotographic photosensitive members were produced in the same manner as in Example 14 except that an amine-bisdiene or -bistriene compound having 15 or 30 asymmetric structures was used.

[Reference Example 1]
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the amount of the polycarbonate resin as the binder resin 17 of the charge transport layer 16 was 10 parts by mass.

[Reference Example 2]
An electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the amount of the polycarbonate resin as the binder resin 17 of the charge transport layer 16 was 31 parts by mass.
However, when the charge transport layer 16 was formed, it was not possible to prepare a charge transport layer coating solution in which the polycarbonate resin was completely dissolved with the same amount of tetrahydrofuran as in Example 14. Therefore, tetrahydrofuran was added to the polycarbonate resin. Was prepared, and a charge transport layer 16 was formed using the charge transport layer coating solution.
However, since the amount of the solvent in the coating solution for the charge transport layer is excessive, white turbidity occurs due to the brushing phenomenon at the end in the longitudinal direction of the cylindrical photoconductor, and the characteristics cannot be evaluated.

[Evaluation 3]
The electrophotographic photoreceptors produced in Examples 14 to 19, Reference Examples 1 and 2 and Comparative Example 11 were evaluated for printing durability and electrical property stability as follows.
Each of the produced electrophotographic photosensitive members was mounted on a digital copying machine (manufactured by Sharp Corporation: AR-C150) with a process speed of 117 mm / sec. After 40,000 sheets of images were formed, the film thickness d1 of the photosensitive layer was measured, and the difference between this value and the film thickness d0 of the photosensitive layer at the time of production was obtained as a film reduction amount Δd (= d0−d1). An evaluation index for printing durability was used.
In addition, a surface potential meter (Gentec Corporation: CATE751) is provided inside the copying machine so that the surface potential of the photoreceptor in the image forming process can be measured, and immediately after charging in an N / N environment of 22 ° C./65% RH. The charging potential V ₀ (V), which is the surface potential of the surface, and the surface potential V _L (V) immediately after the exposure with the laser beam were measured. Similarly, the surface potential _VL immediately after the exposure with the laser beam was measured in an L / L environment of 5 ° C./20% RH. When the surface potential V _L measured in the N / N environment is V _L (1) and the surface potential V _L measured in the L / L environment is V _L (2), V _L (1) and V _L The difference from (2) was determined as potential fluctuation ΔV _L (= V _L (2) −V _L (1)), and used as an evaluation index for the stability of the electrical characteristics. The photosensitive member surface was charged by a negative charging process.
These evaluation results are shown in Table 6.

From the comparison between Examples 14 to 19 and Comparative Example 11, the photoreceptors of Examples 14 to 19 using the organic photoconductive material of the present invention as the charge transport material 13 are those of Comparative Example 11 using Comparative Compound A. It was found that even when a binder resin was added at a higher ratio than the photoconductor, the surface potential V _L under an N / N environment was small and the photoresponsiveness was excellent. It was also found that the potential fluctuation ΔV _L was small, and sufficient photoresponsiveness was exhibited even in an L / L environment.
From comparison between Examples 14 to 19 and Reference Examples 1 and 2, the ratio A / B of the charge transport material (A) to the binder resin (B) is in the range of 10/12 to 10/30. The photoconductor No. 19 has a smaller film loss amount Δd and printing durability than the photoconductor of Reference Example 1 in which the ratio A / B is 10/10 and exceeds 10/12, and the binder resin ratio is low. Was found to be expensive.
As described above, by forming the charge transport layer by including the organic photoconductive material of the present invention, even if the ratio of the binder resin is increased, the printing durability of the charge transport layer is reduced without decreasing the photoresponsiveness. It was possible to improve the performance.

  The electrophotographic photosensitive member of the present invention contains an amine-bisdiene or -bistriene-based organic photoconductive material having an asymmetric structure as a charge transport material, so that it can be partially formed during film formation or long-term storage after the photosensitive member DR. Without causing harmful crystallization, high charging potential, high sensitivity, sufficient photoresponsiveness, and high hole transport capability, which can increase binder resin content due to responsiveness Therefore, it is highly durable and has high industrial applicability in which these characteristics do not deteriorate even when used in a low temperature environment or in a high-speed process.

1 is a schematic cross-sectional view showing a simplified configuration of an electrophotographic photoreceptor that is an example of an embodiment of the present invention. It is a schematic sectional drawing which simplifies and shows the structure of the electrophotographic photoreceptor which is the other example of embodiment of this invention. It is a schematic sectional drawing which simplifies and shows the structure of the electrophotographic photoreceptor which is another example of embodiment of this invention. 1 is a configuration diagram illustrating a simplified configuration of an image forming apparatus including an electrophotographic photosensitive member according to the present invention.

Explanation of symbols

1, 2, 3, 10 Electrophotographic photoreceptor 5 Image forming apparatus 11 Conductive support 12 Charge generation material 13 Charge transport material 14 Photosensitive layer 15 Charge generation layer 16 Charge transport layer 17 Binder resin 18 Intermediate layer 31 Laser beam 32 Charging Device 33 Developing device 34 Transfer charging device 35 Fixing device 36 Cleaner 51 Transfer paper

Claims (11)

Asymmetric amine-bisdiene and amine-bistriene compounds represented by the following general formula (1).

(In the formula, Ar ¹ and Ar ⁴ represent an aryl group or a heterocyclic group which may have a substituent. Ar ² and Ar ³ are different from each other, and an arylene group which may have a substituent or A divalent heterocyclic group, Ar ⁵ represents a hydrogen atom or an aryl group, heterocyclic group, aralkyl group or alkyl group which may have a substituent, provided that Ar ⁴ and Ar ⁵ are an atom or R ¹ , R ² and R ³ may be bonded to each other through an atomic group to form a ring structure, and R ¹ , R ² and R ³ may be a hydrogen atom or an alkyl group, aryl group, heterocyclic group or aralkyl which may have a substituent. And n represents an integer of 1 to 2, and when n is 2, R ² and R ³ may be the same or different.) A compound represented by the following general formula (1) is an asymmetric amine-bisdiene compound represented by the following general formula (2).

(In the formula, Z represents a divalent atomic group composed of hydrogen, nitrogen, carbon, oxygen, and sulfur atoms necessary to form a saturated 4- to 8-membered ring with a benzene ring. A and b are C1-C3 alkyl group, C1-C5 fluoroalkyl group, C1-C5 perfluoroalkyl group, C1-C3 alkoxy group, C1-C8 dialkylamino A group, a halogen atom or a hydrogen atom, wherein m is an integer of 1 to 3. However, when m is 2 or more, a may be the same or different, and l is an integer of 1 to 6. , L is 2 or more, b may be the same or different, and Ar ² , Ar ⁴ and Ar ⁵ have the same meanings as those in the general formula (1). An asymmetric amine-bisdiene compound in which the compound represented by the following general formula (1) is represented by the following general formula (3).

(In the formula, X and Y each represent an optionally substituted methylene group, nitrogen atom, oxygen atom or sulfur atom. Ar ² , Ar ⁴ , Ar ⁵ , a, b, m and l Is synonymous with the general formula (2).   In an electrophotographic photosensitive member provided with a photosensitive layer containing a charge generation material and a charge transport material provided on a conductive support, an asymmetric amine-bis represented by the general formula (1) is used as the charge transport material. An electrophotographic photoreceptor comprising a diene and / or an amine-bistriene compound as an organic photoconductive material.   The electrophotographic photoreceptor according to claim 4, wherein the organic photoconductive material is an asymmetric amine-bisdiene compound represented by the general formula (2).   The electrophotographic photoreceptor according to claim 4, wherein the organic photoconductive material is an asymmetric amine-bisdiene compound represented by the general formula (3).   The charge generation material contains oxotitanium phthalocyanine having a diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 27.2 ° in Cu-Kα characteristic X-ray diffraction (wavelength: 1.54 °). The electrophotographic photosensitive member according to any one of claims 4 to 6.   The electrophotographic photosensitive member according to claim 4, wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer.   The charge transport layer contains a binder resin, and a ratio A / B of the charge transport material (A) and the binder resin (B) in the charge transport layer is 10/12 to 10/30 in mass ratio. The electrophotographic photosensitive member according to claim 4.   The electrophotographic photosensitive member according to claim 4, wherein the photosensitive member has an intermediate layer provided between a conductive support and the photosensitive layer.   An image forming apparatus comprising the electrophotographic photosensitive member according to claim 4.

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