JP2011118342A - Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of being suitably used in a photosensitive layer of the electrophotographic photoreceptor, and excelling in compatibility with a binder resin, strong against an image blurring generation substance, such as an oxidative gas, possesses superior electrical characteristics, and containing a mixture of an alkoxy substitution isomer of a stilbene compound capable of being inexpensively manufactured in the photosensitive layer, and to provide an electrophotographic photoreceptor cartridge which uses the photoreceptor and an image forming apparatus. <P>SOLUTION: Regarding the electrophotographic photoreceptor having the photosensitive layer on a conductive support, the photosensitive layer contains at least two kinds of a Z group substitution isomer of a stilbene based compound having a specific structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member containing a stilbene compound that can be suitably used as a photoconductive material for an electrophotographic photosensitive member in a photosensitive layer, an electrophotographic cartridge using the electrophotographic photosensitive member, and an image forming apparatus. .

The electrophotographic technique is widely used in the fields of copiers, various printers, printing machines, etc. because it is excellent in immediacy and provides high-quality images. As an electrophotographic photoreceptor that is the core of electrophotographic technology, an electrophotographic photoreceptor using an organic photoconductive material (hereinafter simply referred to as “photosensitive material”) that has advantages such as non-pollution, easy film formation, and easy manufacture. Also referred to as "body").
In recent years, the use of image forming apparatuses such as electrophotographic copying machines has been expanded, and the market demand for image quality has been increasing. In particular, in office documents, in addition to the development of mapping technology and latent image forming technology for input, the types of character hieroglyphics are more abundant and finer at the time of output. Due to the spread and development, the reproducibility of a latent image with extremely high image quality that has few defects and unclearness in printed images is required.

  Furthermore, it is a common recognition in the industry that with the recent high performance and low cost of electrophotographic equipment, it is essential to increase the sensitivity of the electrophotographic photosensitive member and reduce the cost of the original material. Of these, in order to achieve high sensitivity, it is necessary not only to optimize the charge generation material, but also to develop a charge transport material with a good matching with it. It is necessary to develop charge transport materials that can be purified by reaction routes and simple purification steps. For this reason, high performance of charge transport materials having a low molecular weight has been attracting attention. The low molecular weight organic photoconductive material has the advantage of low production cost, and the physical properties or electrophotographic characteristics of the coating can be controlled by selecting the type and composition ratio of the binder to be used together. This is preferable because it is relatively easy.

As a conventional technique, a triarylamine-stilbene conjugated compound having an alkoxy group on the stilbene side can be used as a charge transport material. For example, it has been proposed that triarylamine-stilbene conjugated compounds (hereinafter also simply referred to as “stilbene compounds”) described in Patent Documents 1 and 2 can be used as charge transport materials.
However, the compound described in Patent Document 1 has a problem in compatibility with the binder resin, and when used in a high number of parts, a problem of crystal precipitation is likely to occur. In addition, the compound described in Patent Document 2 has relatively low mobility, and there is a point that should be improved in electrical characteristics. When repeatedly used, electrical stability such as a decrease in chargeability and an increase in residual potential is obtained. Sexual deterioration and accompanying image defects occur.

  As described above, there is almost no low molecular weight organic compound having practically good characteristics for producing a photoreceptor.

Japanese Patent Publication No. 63-019867 Japanese Unexamined Patent Publication No. 60-196768

  The present invention has been made in view of the present situation, and its purpose is to be used suitably for a photosensitive layer of an electrophotographic photosensitive member, which has good compatibility with a binder resin, such as an oxidizing gas. An electrophotographic photoreceptor containing a mixture of alkoxy-substituted isomers of a stilbene compound which is strong against image blurring substances, has excellent electrical characteristics and can be produced at low cost, and an electrophotographic cartridge using the photoreceptor, and An object is to provide an image forming apparatus.

  The present inventor made a substituted isomer of a chloromethyl group by a low-cost production method of a benzyl chloride, which is a precursor of a Wordsworth reagent necessary for the synthesis of a stilbene compound having an alkoxy group. By using a mixture of alkoxy-substituted isomers of stilbene compounds obtained by synthesizing reagents and further condensation reaction with aldehyde derivatives for electrophotographic photoreceptors, compatibility with binder resin, oxidation resistance gas resistance, photosensitivity, etc. The properties have been improved relatively well, and when used in the photosensitive layer of an electrophotographic photosensitive member, it exhibits excellent properties such as photosensitivity, residual potential, durability potential stability, environmental stability, fog, and ghost. The inventor has completed the following present invention.

That is, the first gist of the present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer is a stilbene compound having a structure represented by the following general formula [1]. Z
An electrophotographic photoreceptor comprising at least two group-substituted isomers (Claim 1).

(In the above formula [1], Ar ¹ and Ar ² each represent an aryl group which may have an organic group having a substituent constant σp of 0.20 or less in Hammett's rule, and R represents a carbon number of 1 to 4 X and Y are the same or different, each having a substituent constant σp in the Hammett rule of 0.20 or less, an organic group having 1 to 4 carbon atoms, and m and n in the stilbene skeleton. Represents the number of substituents X and Y substituted on the benzene ring, and represents an integer of 0 to 4.)
The second gist of the present invention is that two types of the Z group-substituted isomers of the stilbene compound have a substitution position of the Z group represented by the following general formula [2] with respect to the double bond substituent of the terminal phenyl group. The substitution isomer in the ortho position and the substitution position of the Z group represented by the following general formula [3] are two kinds of substitution isomers in the para position with respect to the double bond substituent of the terminal phenyl group. The electrophotographic photosensitive member is characterized in that (claim 2).

(In the above formula [2] or [3], Ar ¹ and Ar ² are the substituent constants σp in Hammett's rule, respectively.
Represents an aryl group which may have an organic group of 0.20 or less, and R represents an alkyl group having 1 to 4 carbon atoms. X and Y are the same or different, and the substituent constant σp in Hammett's rule is
Is an organic group having 1 to 4 carbon atoms, m and n represent the number of substituents X and Y substituted on the benzene ring in the stilbene skeleton, and represent an integer of 0 to 4 . )
The third gist of the present invention is that the ortho-position Z group-substituted isomer of the stilbene compound represented by the general formula [2] and the para-position Z group-substituted isomer of the stilbene compound represented by the general formula [3] In the electrophotographic photosensitive member, wherein the ratio is 90/10 to 10/90 (claim 3).

The fourth gist of the present invention is the above-described electrophotographic photosensitive member of the present invention, charging means for charging the electrophotographic photosensitive member, and an image for forming an electrostatic latent image by image exposure on the charged electrophotographic photosensitive member. An exposure unit; a developing unit that develops the electrostatic latent image with toner; a transfer unit that transfers the toner to a transfer target; a fixing unit that fixes the toner transferred to the transfer target; and the electrophotographic photosensitive member An electrophotographic cartridge comprising at least one selected from cleaning means for collecting the toner adhering to the body (claim 4).

According to a fifth aspect of the present invention, there is provided the electrophotographic photosensitive member of the present invention, a charging unit for charging the electrophotographic photosensitive member, and an exposure unit for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. And a developing unit that develops the electrostatic latent image with toner, a transfer unit that transfers the toner to a transfer target, and a fixing unit that fixes the toner transferred to the transfer target. The present invention resides in an image forming apparatus (claim 5).

  The mixture of the alkoxy group-substituted isomers of the low molecular weight stilbene compound of the present invention has good properties such as compatibility with the binder resin, photosensitivity, residual potential, etc., little fatigue deterioration when used repeatedly, and stability. good. When used in an electrophotographic photosensitive member, it is possible to provide an electrophotographic photosensitive member that exhibits excellent electric potential stability during durability and environmental stability, and printing can be performed by using this electrophotographic photosensitive member. In some cases, it is possible to provide an electrophotographic cartridge and an image forming apparatus free from image defects such as fogging and ghosting.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. 1 is an X-ray diffraction pattern of oxytitanium phthalocyanine used in Examples.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the present invention. it can.
≪Stilbene compounds≫
The stilbene compound of the present invention is a mixture of at least two Z group-substituted isomers of a stilbene compound having a structure represented by the following general formula [1].

(In the above formula [1], Ar ¹ and Ar ² each represent an aryl group which may have an organic group having a substituent constant σp of 0.20 or less in Hammett's rule, and R represents a carbon number of 1 to 4 X and Y are the same or different, each having a substituent constant σp in the Hammett rule of 0.20 or less, an organic group having 1 to 4 carbon atoms, and m and n in the stilbene skeleton. Represents the number of substituents X and Y substituted on the benzene ring, and represents an integer of 0 to 4.)
Here, Hammett's rule is an empirical rule used to explain the effect of a substituent in an aromatic compound on the electronic state of the aromatic ring, and the substituent constant σp of the substituted benzene is the electron donation / It can be said that this is a value obtained by quantifying the degree of suction. If the σp value is positive, the substituted benzoic acid is more acidic than the unsubstituted one, that is, an electron-withdrawing substituent. Conversely, when the σp value is negative, an electron donating substituent is formed. Table 1 shows σp values of representative substituents (The Chemical Society of Japan, “Chemical Handbook, Basic Edition II, 4th revised edition”, Maruzen Co., Ltd., published on September 30, 1993, p.364-365). .

In the formula [1], Ar ¹ and Ar ² are each an aryl group which may have an organic group having a substituent constant σp of 0.20 or less according to Hammett's rule. The value of the substituent constant σp in the Hammett rule is preferably 0.00 or less, and particularly preferably −0.10 or less from the viewpoint of electrical characteristics. On the other hand, the lower limit is preferably −0.3 or more from the viewpoint of acid resistance. Examples of the organic group include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group having 2 to 4 carbon atoms, and specifically include a methyl group and an ethyl group. N-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, methoxy group, ethoxy group, propoxy group, butoxy group, N, N-dimethylamino group, N, N-diethylamino group, etc. Can be mentioned. Among these, an organic group having 1 to 2 carbon atoms is particularly preferable from the viewpoint of electrical characteristics and production cost, and specific examples include a methyl group, a methoxy group, an ethyl group, and an ethoxy group.

In the formula [1], Ar ¹ and Ar ² represent an aromatic hydrocarbon group, and when Ar ¹ and Ar ² are a monocyclic hydrocarbon group, a phenyl group is exemplified, and Ar ¹ , When Ar ² is a condensed polycyclic hydrocarbon, a naphthyl group, a fluorenyl group, an anthryl group, a phenanthryl group, a pyrenyl group, and the like can be given. Among these, a phenyl group, a fluorenyl group, and a naphthyl group are preferable in terms of electrical characteristics, and a fluorenyl group is more preferable. In view of both electric characteristics and production cost, it is particularly preferable that Ar ¹ and Ar ² are phenyl groups.

In the above formula [1], X and Y each represents an organic group having 1 to 4 carbon atoms and a substituent constant σp in the Hammett rule of 0.20 or less. The value of the substituent constant σp in the Hammett rule is preferably 0.00 or less, particularly preferably −0.10 or less from the viewpoint of electrical characteristics. On the other hand, the lower limit is preferably −0.3 or more from the viewpoint of acid resistance. Examples of the organic group having 1 to 4 carbon atoms include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a dialkylamino group having 2 to 4 carbon atoms. Specifically, , Methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, methoxy group, ethoxy group, propoxy group, butoxy group, N, N-dimethylamino group, N, N-diethylamino group etc. are mentioned. Among these, an organic group having 1 carbon atom is particularly preferable from the viewpoint of electrical characteristics and production cost, and specific examples include a methyl group and a methoxy group.

In the formula [1], m and n represent the number of substituents X and Y substituted on the benzene ring in the stilbene skeleton, and are integers of 0 to 4, preferably integers of 0 to 1, From the viewpoint of cost, it is particularly preferable that m = n = 0.
In the formula [1], R is an alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. From the viewpoint of production cost, R is particularly preferably a methyl group or an ethyl group. When the number of carbon atoms in the alkyl group is 5 or more, there is a risk that electrical characteristics and acid gas resistance will deteriorate.

In the above formula [1], examples of the substitution position of the alkoxy group used as the substituent of the phenyl group at the stilbene terminal include a para position, a meta position, and an ortho position. From the viewpoints of electrical properties, production convenience, cost, and the like, the substitution position of the alkoxy group is particularly preferably an ortho position represented by the following formula [2] and a para position represented by the following formula [3].

Equations [2] and [3] are similar to Equation [1].
The ratio (mol%) of the alkoxy group-substituted isomer is not particularly limited, but in the production method of the present invention, the meta-position-substituted isomer depends on the reactivity of the raw material alkoxybenzene (the alkoxy group is an ortho-para-oriented substituent). The body is difficult to obtain more than 10% of the total isomer, usually 10% or less, preferably in the range of 0-8%, not included in terms of electrical properties and manufacturing convenience Particularly preferred. On the other hand, the ratio of the ortho isomer represented by the formula [2] and the para isomer represented by the formula [3] is usually preferably within a range of 95/5 to 5/95, The compatibility with the resin is more preferably in the range of 90/10 to 10/90, and the electrical characteristics are particularly preferably in the range of 80/20 to 20/80.

The molecular weight of the formula [1] is usually 500 or less, preferably 460 or less. When this range is satisfied, the cleaning performance is improved when the actual image is evaluated, and it is easy to prevent noise and filming. This is presumably because the surface hardness of the photoreceptor is high by using a low molecular charge transport material. Accordingly, in the formula [1], it is particularly preferable to adjust the substituents Ar ¹ and Ar ² and R, X, Y, m, and n in view of the molecular weight. On the other hand, the lower limit is preferably 400 or more from the viewpoint of electrical characteristics.

  As typical examples of the stilbene compounds represented by the formula [1], the following exemplified compounds CT-1a to CT-10c can be mentioned. However, the stilbene compounds related to the present invention are not limited to these compounds.

A mixture of alkoxy-substituted isomers of these stilbene compounds can be easily synthesized by a known method. For example, an isomer mixture of the exemplary compound CT-2 series of the present invention can be produced from a state where isomers of ethoxybenzyl chloride are mixed according to the following reaction scheme 1 (Production Example 1).
[Scheme 1]

Ethoxybenzene is dissolved in 1,4-dioxane and reacted by adding paraformaldehyde and concentrated hydrochloric acid to obtain an isomer mixture of ethoxybenzyl chloride. Triethyl phosphite is added thereto and heated to 165 ° C. to obtain a phosphoric acid ester derivative (Wordsworth reagent). Wordsworth reagent and 4,4-dimethyltriphenylamine aldehyde (DMTPAA) are dissolved in dimethylformamide (DMF) solvent and condensed by adding a base. A mixture of c can be obtained.

In addition, the mixture of the exemplary compounds CT-1a and CT-1c of the present invention can be produced by a predetermined reaction after separately synthesizing and mixing the Wordsworth reagents of methoxy-substituted isomerism according to the following reaction scheme 2. .
[Scheme 2]

After individually synthesizing p-methoxy or o-methoxy Wordsworth reagents and mixing them in any ratio, the desired mixture of CT-1a and CT-1c can be obtained in any ratio by reaction with DMTPAA. (See Reference Production Example 1).
≪Electrophotographic photoreceptor≫
The configuration of the electrophotographic photosensitive member of the present invention will be described below. The electrophotographic photoreceptor of the present invention has a structure as long as a photosensitive layer containing an alkoxy group-substituted isomer of the stilbene compound represented by the above formula [1] is provided on a conductive support. Is not particularly limited. Among them, a multilayer photoreceptor in which a charge generation layer and a charge transport layer are laminated is preferable, and in particular, the charge transport layer of the multilayer photoreceptor is an alkoxy of a stilbene compound represented by the above formula [1]. It preferably contains a group-substituted isomer.

<Conductive support>
There are no particular restrictions on the conductive support, but for example, metal materials such as aluminum, aluminum alloys, stainless steel, copper and nickel, and conductive powders such as metal, carbon and tin oxide can be added to make the conductive material conductive. Mainly used are resin, glass, paper, or the like obtained by depositing or applying the applied resin material or a conductive material such as aluminum, nickel, ITO (indium tin oxide) on the surface. These may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and arbitrary ratios. As a form of the conductive support, a drum form, a sheet form, a belt form or the like is used. Furthermore, a conductive material having an appropriate resistance value may be used on a conductive support made of a metal material in order to control conductivity and surface properties and to cover defects.

Moreover, when using metal materials, such as an aluminum alloy, as an electroconductive support body, you may use, after giving an anodic oxide film. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
The surface of the conductive support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle size with the material constituting the conductive support. In order to reduce the cost, it is possible to use the drawing tube as it is without performing the cutting process.

<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin or a resin in which particles such as a metal oxide are dispersed is used. The undercoat layer may be a single layer or a plurality of layers.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of a several crystal state may be contained.

In addition, various particle sizes of metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle size is preferably 10 nm or more and 100 nm or less, and particularly 10 nm or more and 50 nm or less. preferable. This average primary particle size can be obtained from a TEM photograph or the like.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. The binder resin used for the undercoat layer is epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, chloride resin. Cellulose esters such as vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacryl resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, nitrocellulose Resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconium The organic zirconium compound alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanium alkoxide compounds include known binder resins such as a silane coupling agent. These may be used alone or in combination of two or more in any combination and ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

The use ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected. From the viewpoint of the stability of the dispersion and the coating property, the binder resin is usually 10% by mass or more, It is preferable to use in the range of 500 mass% or less.
The thickness of the undercoat layer is arbitrary as long as the effects of the present invention are not significantly impaired, but the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, repeat characteristics, and coating properties during production of the electrophotographic photosensitive member. Therefore, it is usually 0.01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less. A known antioxidant or the like may be mixed in the undercoat layer. For the purpose of preventing image defects, pigment particles, resin particles and the like may be included.

<Photosensitive layer>
The photosensitive layer is formed on the above-mentioned conductive support (or on the undercoat layer when the above-described undercoat layer is provided). The photosensitive layer is a layer containing the stilbene compound represented by the general formula (I) described above, and the charge generation material and the charge transport material (including the stilbene compound) are present in the same layer. A single layer structure in which they are dispersed in a binder resin (hereinafter referred to as “single layer type photosensitive layer” as appropriate), a charge generation layer in which a charge generation material is dispersed in a binder resin, and a charge transport material ( A functionally-separated layered structure composed of two or more layers including a charge transport layer dispersed in a binder resin (including a stilbene compound) (hereinafter referred to as “laminated photosensitive layer” as appropriate). However, any form may be sufficient.

In addition, as the laminated photosensitive layer, a charge-generating layer and a charge transport layer are laminated in this order from the conductive support side, and conversely, a charge transport layer and a charge generation layer are formed from the conductive support side. There are reverse laminated photosensitive layers provided in order, and any of them can be adopted, but a forward laminated photosensitive layer that can exhibit the most balanced photoconductivity is preferable.
<Laminated photosensitive layer>
[Charge generation layer]
The charge generation layer of the laminated photosensitive layer (function-separated type photosensitive layer) contains a charge generation material and usually contains a binder resin and other components used as necessary. Such a charge generation layer is prepared, for example, by dissolving or dispersing a charge generation material and a binder resin in a solvent or dispersion medium to prepare a coating solution, and in the case of a sequentially laminated photosensitive layer, this is formed on a conductive support. (If an undercoat layer is provided, it can be obtained on the undercoat layer). In the case of a reverse laminated type photosensitive layer, it can be obtained by coating on a charge transport layer and drying.

  Examples of the charge generation material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments. Organic photoconductive materials are preferred, and organic photoconductive materials are particularly preferable. Pigments are preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When using a phthalocyanine pigment as a charge generation material, specifically, metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum, or oxides thereof, halides, Those having each crystal form of coordinated phthalocyanines such as hydroxides and alkoxides, and phthalocyanine dimers using oxygen atoms as bridging atoms are used. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and type I, type II, etc. The [mu] -oxo-aluminum phthalocyanine dimer is preferred.

Among these phthalocyanines, A-type (also known as β-type), B-type (also known as α-type), and powder X-ray diffraction angle 2θ (± 0.2 °) are 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type hydroxygallium phthalocyanine, hydroxygallium phthalocyanine having the strongest peak at 28.1 °, or 26. Hydroxygallium phthalocyanine having no peak at 2 °, a clear peak at 28.1 °, and a full width at half maximum W of 25.9 ° of 0.1 ° ≦ W ≦ 0.4 ° G-type μ-oxo-gallium phthalocyanine dimer and the like are particularly preferable.

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a highly sensitive photoreceptor can be obtained with respect to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm. Further, when an azo pigment such as monoazo, diazo, or trisazo is used, white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength (for example, a wavelength in the range of 380 nm to 500 nm). It is possible to obtain a photoreceptor having sufficient sensitivity to the laser beam).

  The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be the one that gave rise to. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

  On the other hand, when an azo pigment is used as a charge generation material, various known azo pigments can be used as long as they have sensitivity to a light source for light input. Trisazo pigments are preferably used. Examples of preferred azo pigments are shown below.

  When the organic pigments exemplified above are used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

  The binder resin used for the charge generation layer constituting the multilayer photosensitive layer is not particularly limited. Polyvinyl acetal resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, etc. Polyacrylamide resin, polyamide resin, polyvinyl pyridine resin, cellulose resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, Vinyl chloride such as zein, vinyl chloride-vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer -Insulating resin such as vinyl acetate copolymer, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, styrene-alkyd resin, silicon-alkyd resin, phenol-formaldehyde resin, and poly-N-vinylcarbazole , Organic photoconductive polymers such as polyvinyl anthracene and polyvinyl perylene. Any one of these binder resins may be used alone, or two or more thereof may be mixed and used in any combination.

Specifically, the charge generation layer is prepared by dispersing a charge generation material in a solution obtained by dissolving the above-described binder resin in an organic solvent to prepare a coating solution, which is then formed on a conductive support (when an undercoat layer is provided). Is formed by coating (on the undercoat layer).
The solvent used for preparing the coating solution is not particularly limited as long as it dissolves the binder resin. For example, saturated aliphatic solvents such as pentane, hexane, octane, and nonane, and aromatics such as toluene, xylene, and anisole. Group solvents, halogenated aromatic solvents such as chlorobenzene, dichlorobenzene, chloronaphthalene, amide solvents such as dimethylformamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-butanol, benzyl alcohol, etc. Alcohol solvents, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chain or cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone, methyl formate, ethyl acetate, Acetic acid n-bu Chains such as ester solvents such as benzene, halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, etc. Or cyclic ether solvents, acetonitrile, dimethyl sulfoxide, sulfolane, aprotic polar solvents such as hexamethylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, triethylamine-containing nitrogen Compound, mineral oil such as ligroin, water and the like. Any one of these may be used alone, or two or more of these may be used in combination. In addition, when providing the above-mentioned undercoat layer, what does not melt | dissolve this undercoat layer is preferable.

  In the charge generation layer, the compounding ratio (mass ratio) of the binder resin and the charge generation material is usually 10 parts by mass or more, preferably 30 parts by mass or more, and usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. The range is not more than part by mass, preferably not more than 500 parts by mass. The film thickness of the electrification generation layer is usually in the range of 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material. On the other hand, if the ratio of the charge generating substance is too low, the sensitivity as a photoreceptor may be reduced.

As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. At this time, it is effective to refine the particles to a particle size in the range of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.
<Charge transport layer>
The charge transport layer of the multilayer photoreceptor contains a charge transport material and usually contains a binder resin and other components used as necessary. Specifically, such a charge transport layer is prepared by dissolving or dispersing a charge transport material or the like and a binder resin in a solvent to prepare a coating solution. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (on the undercoat layer when an undercoat layer is provided).

As the charge transport material, an alkoxy group-substituted isomer mixture of the stilbene compound of the present invention is preferably used. The stilbene compound of the present invention may be a mixture of isomers having the same alkoxy group, or may be a combination of compounds having a plurality of types of alkoxy groups in any ratio.
In addition to the stilbene compound of the present invention, other known charge transport materials may be used in combination. When other charge transport materials are used in combination, the type is not particularly limited, but for example, carbazole derivatives, hydrazone compounds, aromatic amine derivatives, enamine derivatives, butadiene derivatives and those in which a plurality of these derivatives are bonded are preferable. More specifically, it is described in JP-A-2-230255, JP-A-63-225660, JP-A-58-198043, JP-B-58-32372, and JP-B-7-21646. Compounds are preferably used. Any of these charge transport materials may be used alone, or a plurality of types may be used in any combination. When the stilbene compound of the present invention is used in combination with another known charge transport material, the content ratio (% by mass) of the charge transport material to be used in the total amount of the charge transport material is not particularly limited, but is 1% or more. It is preferably within a range of 20% or less, and particularly preferably within a range of 3% or more and 10% or less in order to more effectively exert the role of the stilbene compound of the present invention.

The binder resin is used for securing the film strength. Examples of the binder resin for the charge transport layer include polymers and copolymers of vinyl compounds such as butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, and ethyl vinyl ether. Polymer, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicon resin, silicon-alkyd resin, poly-N -Vinyl carbazole resin etc. are mentioned. Of these, polycarbonate resins and polyarylate resins are preferred. These binder resins can also be used after being crosslinked by heat, light or the like using an appropriate curing agent. Any one of these binder resins may be used alone, or two or more thereof may be used in any combination.

  As for the ratio of the binder resin to the charge transport material, the charge transport material is used in a ratio of 20 parts by mass or more with respect to 100 parts by mass of the binder resin. Among these, 30 parts by mass or more is preferable from the viewpoint of residual potential reduction, and 40 parts by mass or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 150 parts by mass or less. Among these, 110 parts by mass or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 90 parts by mass or less is more preferable from the viewpoint of printing durability, and 80 parts by mass or less is most preferable from the viewpoint of scratch resistance.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, on the other hand, usually 50 μm or less, preferably 45 μm or less, from the viewpoint of long life, image stability, and high resolution. Is in the range of 30 μm or less.
<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed using a binder resin in order to ensure film strength, in the same manner as the charge transport layer of the multilayer photoreceptor, in addition to the charge generation material and the charge transport material. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (or an undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.

The types of the charge transport material and the binder resin and the use ratios thereof are the same as those described for the charge transport layer of the multilayer photoreceptor. A charge generation material is further dispersed in a charge transport medium comprising these charge transport materials and a binder resin.
As the charge generation material, the same materials as those described for the charge generation layer of the multilayer photoreceptor can be used. However, in the case of a photosensitive layer of a single layer type photoreceptor, it is necessary to sufficiently reduce the particle size of the charge generating material. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.
If the amount of the charge generating material dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. The total amount of the layer-type photosensitive layer is usually 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less.

In addition, the usage ratio of the binder resin and the charge generation material in the single-layer type photosensitive layer is such that the charge generation material is usually 0.1 parts by weight or more, preferably 1 part by weight or more, based on 100 parts by weight of the binder resin. It is 30 mass parts or less, Preferably it is set as the range of 10 mass parts or less.
The film thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less.

<Other functional layers>
For the purpose of improving film-forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc., in both the photosensitive layer and each layer constituting it, both in the multilayer type photosensitive member and the single layer type photosensitive member. Additives such as well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents may be included.

Further, in both the laminated type photoreceptor and the single layer type photoreceptor, the photosensitive layer formed by the above procedure may be the uppermost layer, that is, the surface layer, but another layer may be provided on the photosensitive layer and used as the surface layer. Good.
For example, a protective layer may be provided for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like.
The protective layer is formed by containing a conductive material in a suitable binder resin, or a copolymer using a compound having charge transporting ability such as a triphenylamine skeleton described in JP-A-9-190004. Can be formed.

Examples of the conductive material used for the protective layer include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, and oxide. Metal oxides such as titanium, tin oxide-antimony oxide, aluminum oxide, and zinc oxide can be used, but are not limited thereto.
As the binder resin used for the protective layer, known resins such as polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, and siloxane resin can be used. Also, a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and a copolymer of the above resin can be used.

The electrical resistance of the protective layer is usually in the range of 10 ⁹ Ω · cm to 10 ¹⁴ Ω · cm. When the electric resistance is higher than the range, the residual potential is increased, resulting in an image with much fogging. On the other hand, when the electric resistance is lower than the range, the image is blurred and the resolution is reduced. Further, the protective layer must be configured so as not to substantially prevent transmission of light irradiated during image exposure. Further, for the purpose of reducing the frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper, etc., the surface layer is made of fluorine resin, silicon resin, polyethylene resin, or the like. You may contain the particle | grains which consist of these resin, and the particle | grains of an inorganic compound. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.

<Method for forming each layer>
Each layer constituting the above-described photoreceptor is formed by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating on a conductive support obtained by dissolving or dispersing a substance to be contained in a solvent. It is formed by repeating a coating / drying step sequentially for each layer by a known method such as coating.

  There are no particular restrictions on the solvent or dispersion medium used for the preparation of the coating solution, but specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, ketones such as 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, Chlorinated hydrocarbons such as chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, Diethyl Min, triethanolamine, ethylenediamine, nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

The amount of the solvent or the dispersion medium used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, it is appropriately determined so that the physical properties such as the solid content concentration and viscosity of the coating liquid are within a desired range. It is preferable to adjust.
For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, preferably 10% by mass or more, and usually 40% by mass or less. The range is preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 500 mPa · s or lower, preferably 400 mPa · s or lower, at the temperature during use.

  In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. In addition, the viscosity of the coating solution is usually 0.01 mPa · s or higher, preferably 0.1 mPa · s or higher, and usually 20 mPa · s or lower, preferably 10 mPa · s or lower, at the temperature during use.

Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.
The coating solution is preferably dried by touching at room temperature, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.

≪Image forming device≫
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6, and a fixing device as necessary. A device 7 is provided.
The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. As the charging device, a corona charging device such as a corotron or a scorotron, a direct charging device (contact type charging device) for charging a direct charging member to which a voltage is applied by contacting the photosensitive member surface, and the like are often used. Examples of the direct charging device include a charging roller and a charging brush. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose an alternating current on a direct current.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, if exposure is performed with monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength of 600 nm to 700 nm, slightly shorter wavelength, monochromatic light with a wavelength of 380 nm to 500 nm, or the like. Good.

The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. This replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.
The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicon resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.
The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as silicon resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with a resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the toner T is arbitrary, and in addition to the powdery toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 to 8 μm is preferable, and the toner particles are used in various shapes ranging from a nearly spherical shape to a shape outside the spherical shape on the potato. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like disposed so as to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may be omitted.

The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. The upper and lower fixing members 71 and 72 are known heat fixings such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, or a fixing sheet. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicon oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of an arbitrary method such as heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like can be provided.

In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.
Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.

The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.
When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.

After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.
In addition to the above-described configuration, the image forming apparatus may be configured to perform, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.
The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic photosensitive member cartridge may be configured to be detachable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In this case, for example, when the electrophotographic photosensitive member 1 and other members are deteriorated, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic photosensitive member cartridge is mounted on the main body of the image forming apparatus. This facilitates maintenance and management of the image forming apparatus.

Hereinafter, the present invention will be described in more detail with reference to Production Examples, Reference Production Examples, Examples and Comparative Examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.
<Manufacture of stilbene compounds>
(Production Example 1: Production of mixture of exemplified compounds CT-1a to c)
Under nitrogen atmosphere, paraformaldehyde 10.81 g (monomer conversion 360 mmol), anisole 32.45 g (300 mmol) was added to 1,4-dioxane 200 ml, and 35 wt% concentrated hydrochloric acid 65 ml (720 mmol) was added dropwise. The ^mixture was stirred at 80 ^° C. for 3 hours. The obtained liquid was separated by a liquid separation load, the organic layer was washed with an aqueous sodium bicarbonate solution, dried over alumina, and the solvent was distilled off under reduced pressure. The residual oil was distilled again under reduced pressure to obtain 34.77 g (222 mmol, 74% yield) of a mixture of methoxybenzyl chloride. As a result of analysis by nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer), the isomer ratio of methoxybenzyl chloride was p / m / o = 73/11/16.

Under a nitrogen atmosphere, 39.88 g (240 mmol) of triethyl phosphite was added to 31.33 g (200 mmol) of an isomer mixture of methoxybenzyl chloride (p / m / o = 73/11/16), and 2 at 165 ^° C. Stir for hours. Then, excess triethyl phosphite was distilled off under reduced pressure, and the mixture was cooled to room temperature to obtain 50.62 g (196 mmol, yield 98%) of a mixture of phosphate esters. As a result of analysis by nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer), the isomer ratio of the phosphate ester was p / m / o = 75/8/17.

Under a nitrogen atmosphere, DMTPAA 52.74 g (175 mmol) and a mixture of phosphate ester compound 50.61 g (196 mmol) were dissolved in DMF 200 ml and stirred at room temperature with potassium tert-butoxide 23.56 g (210 mmol). ) Was added slowly (cooling if necessary) and stirred for an additional hour. This solution was dropped into 600 ml of a methanol / ice water (v / v = 8: 2) mixed solution and crystallized. The obtained crystals were passed through flash column chromatography (silica gel 1500 g, developing solvent: toluene / hexane = 1/2), and reprecipitated with 600 ml of a mixture of methanol / ice water (v / v = 8: 2). A mixture of CT-1a-c (61.71 g, 152 mmol, 87% yield) was obtained as a light yellow powder. The composition of this mixture was analyzed by high performance liquid chromatography (column: inert sill ODS-3V manufactured by GL Sciences Inc., solvent: acetonitrile / water (v / v = 90/10)), and CT-1a / CT- 1b / CT-1c = 75/10/15.

(Production Example 2: Production of mixture of exemplified compounds CT-1a and CT-1c)
Under nitrogen atmosphere, paraformaldehyde 9.01 g (monomer conversion 300 mmol) and anisole 48.66 g (450 mmol) were added to 1,4-dioxane 200 ml, and 35 wt% concentrated hydrochloric acid 38 ml (420 mmol).
Was added dropwise and stirred at 80 ^° C. for 3 hours. The obtained liquid was separated by a liquid separation load, the organic layer was washed with an aqueous sodium bicarbonate solution, dried over alumina, and the solvent and excess anisole were distilled off by distillation under reduced pressure. The residual oil was again distilled under reduced pressure to obtain 32.89 g (210 mmol, yield 70%) of a mixture of methoxybenzyl chloride. As a result of analysis by nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer), the isomer ratio of methoxybenzyl chloride was p / o = 3.04 / 1 and meta-substituted isomer was not detected. It was.

Under a nitrogen atmosphere, 39.88 g (240 mmol) of triethyl phosphite was added to 31.33 g (200 mmol) of the isomer mixture of methoxybenzyl chloride (p / o = 3.04 / 1) and stirred at 165 ^° C. for 2 hours. . Then, excess triethyl phosphite was distilled off under reduced pressure, and the mixture was cooled to room temperature to obtain 50.62 g (196 mmol, yield 98%) of a mixture of phosphate esters. As a result of analysis by nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer), the isomer ratio of the phosphate ester was p / o = 3/1.

In a nitrogen atmosphere, DMTPAA 52.74 g (175 mmol) and a mixture of the above phosphate ester compound 50.61 g (196 mmol) were dissolved in DMF 200 ml and stirred at room temperature with potassium tert-butoxide.
23.56 g (210 mmol) was added slowly (cooling if necessary) and stirred for an additional hour. This solution was dropped into 600 ml of a methanol / ice water (v / v = 8: 2) mixed solution and crystallized. The obtained crystals were passed through flash column chromatography (silica gel 1500 g, developing solvent: toluene / hexane = 1/2), and reprecipitated with 600 ml of a mixture of methanol / ice water (v / v = 8: 2). A mixture of CT-1a and CT-1c (60.32 g, 149 mmol, 85% yield) was obtained as a pale yellow powder. The composition of this mixture was analyzed by high performance liquid chromatography (column: inert sill ODS-3V manufactured by GL Sciences Inc., solvent: acetonitrile / water (v / v = 90/10)), and CT-1a / CT- 1c = 7/3.

(Production Example 3: Production of mixture of exemplified compounds CT-2a to c)
Except that ethoxybenzene was used as a raw material instead of anisole, a mixture of exemplary compounds CT-2a to c was obtained as pale yellow crystals in the same manner as in Production Example 1. As a result of analyzing the composition of this mixture by high performance liquid chromatography (column: Inertosyl ODS-3V manufactured by GL Sciences Inc., solvent: acetonitrile / water (v / v = 90/10)), CT-2a / CT- 2b / CT-2c = 71/8/21.

(Production Example 4: Production of mixture of exemplified compounds CT-2a and CT-2c)
A mixture of the exemplified compounds CT-2a and CT-2c was obtained as pale yellow crystals by the same operation as in Production Example 2, except that ethoxybenzene was used as a raw material instead of anisole. As a result of analyzing the composition of this mixture by high performance liquid chromatography (column: Inertosyl ODS-3V manufactured by GL Sciences Inc., solvent: acetonitrile / water (v / v = 90/10)), CT-2a / CT- 2c = 2.1 / 1.

(Reference Production Example 1: Production of free mixture of exemplified compounds CT-1a and CT-1c)
Under a nitrogen atmosphere, 133 wt (1474 mmol) of 35 wt% concentrated hydrochloric acid was added dropwise to 50.90 g (368 mmol) of p-methoxybenzyl alcohol, and the mixture was stirred at 60 ^° C. for 3 hours. After cooling to room temperature, 100 ml of toluene and 100 ml of demineralized water were added, the organic layer was extracted, washed with aqueous sodium bicarbonate, dried over alumina, and toluene was distilled off by distillation under reduced pressure. The residual oil was distilled again under reduced pressure to obtain 49.65 g (317 mmol, yield 86%) of p-methoxybenzyl chloride as a colorless oil. It was analyzed by nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer) and confirmed to be a pure product of p-methoxybenzyl chloride.

  Under the same atmosphere as above except that 50.90 g (368 mmol) of o-methoxybenzyl alcohol was used instead of p-methoxybenzyl alcohol as a raw material in a nitrogen atmosphere, 35.24 g (225 mmol of o-methoxybenzyl chloride) was used. Yield 61%) as a colorless oil. It was analyzed by nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer) and confirmed to be pure o-methoxybenzyl chloride.

Further, by the same operation as in Production Example 1, phosphoric acid ester forms of p-methoxybenzyl chloride and o-methoxybenzyl chloride were obtained (para isomer: 78.59 g (304 mmol, yield: 96%)). Body: 54.62 g (212 mmol, 94% yield)).
The two types of phosphate esters obtained by the above operation can be mixed at an arbitrary ratio, and a mixture of CT-1a and CT-1c at an arbitrary ratio can be obtained by the same operation as in Production Example 1.

(Reference Production Example 2: Production of free mixture of exemplified compounds CT-2a and CT-2c)
CT-2a and CT- were prepared in the same manner as in Reference Production Example 1, except that p-ethoxybenzyl alcohol or o-ethoxybenzyl alcohol was used as a raw material instead of p-methoxybenzyl alcohol or o-methoxybenzyl alcohol. Mixtures of any ratio of 2c can also be obtained.

<Production of electrophotographic photoreceptor>
(Example 1: Electrophotographic photoreceptor A1)
Using a conductive support with an aluminum vapor deposition layer (thickness 70 nm) formed on the surface of a biaxially stretched polyethylene terephthalate resin film (thickness 75 μm), on the aluminum vapor deposition layer of the conductive support, the following undercoat layer Dispersion liquid with a bar coater, film thickness after drying is 1.25μm
The undercoat layer was formed by coating and drying.

The undercoat layer dispersion was prepared by the following method. That is, rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide Disperse the surface-treated titanium oxide obtained by mixing in a fluid mixing kneader ("SMG300" manufactured by Kawata Co., Ltd.) and mixing at high speed at a rotational peripheral speed of 34.5 m / sec using a methanol / 1-propanol ball mill. Thus, a dispersion slurry of hydrophobized titanium oxide was obtained. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (F)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula ( G)] / hexamethylenediamine [compound represented by the following formula (H)] / decamethylene dicarboxylic acid [compound represented by the following formula (I)] / octadecamethylene dicarboxylic acid [
The compound molar ratio of the compound represented by the following formula (J)] is a polyamide pellet obtained by stirring and mixing with a copolyamide pellet having a composition molar ratio of 60% / 15% / 5% / 15% / 5%. Is dissolved, and then ultrasonic dispersion treatment is performed, so that the mass ratio of methanol / 1-propanol / toluene is 71/2 and the hydrophobically treated titanium oxide / copolymer polyamide is contained at a mass ratio of 3/1. An undercoat layer dispersion having a solid content concentration of 18.0% was obtained.

  Next, 10 parts of oxytitanium phthalocyanine having a powder X-ray diffraction spectrum shown in FIG. In addition to 150 parts of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. 160 parts by mass of the pigment dispersion thus obtained, 100 parts by mass of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.), and an appropriate amount of 1,2-dimethoxy Ethane was mixed to finally produce a dispersion having a solid concentration of 4.0%.

The dispersion was applied on the undercoat layer with a wire bar so that the film thickness after drying was 0.4 μm, and then dried to form a charge generation layer. Next, 80 parts by mass of a mixture of CT-1a, CT-1b and CT-1c obtained in Production Example 1, 100 parts by mass of the following polycarbonate resin (A), 0.05 parts by mass of silicone oil as a leveling agent and tetrahydrofuran A coating solution for forming a charge transport layer was prepared by mixing with 640 parts of a mixed solvent of toluene (80% by weight of tetrahydrofuran, 20% by weight of toluene). This solution is applied onto the above-described charge generation layer using an applicator so that the film thickness after drying is 25 μm, and dried at 125 ° C. for 20 minutes to form a charge transport layer, whereby the photosensitive sheet A1 is obtained. Produced. The viscosity average molecular weight of the polycarbonate resin (A) was 30,000.

The measuring method of the viscosity average molecular weight of the used binder resin is as follows. Dissolve the resin in dichloromethane to prepare a solution with a concentration C of 6.00 g / L. The flow time t of the sample solution is measured in a constant temperature water bath set to 20.0 ° C. using an Ubbelohde capillary viscometer with a flow time t ₀ of the solvent (dichloromethane) of 136.16 seconds. The viscosity average molecular weight Mv is calculated according to the following formula.

a = 0.438 × η _sp +1 η _sp = t / t ₀ −1
b = 100 × η _sp / C C = 6.00 (g / L)
η = b / a
Mv = 3207 × η ^1.205
(Examples 2 to 11: electrophotographic photoreceptors A2 to A11)
Electrophotographic photoreceptors A2 to A11 as examples were obtained in the same manner as in Example 1 except that instead of the exemplified compounds CT-1a to c, a mixture of CT-1a and CT-1c was used as the charge transport material. It was. The electrophotographic photoreceptor A11 showed slight crystal precipitation, but was able to measure electrical characteristics. The composition of the charge transport material is shown in Table 2.

(Comparative Example 1: Electrophotographic photoreceptor P1)
An electrophotographic photosensitive member P1 as a comparative example was obtained in the same manner as in Example 1 except that the charge transport material CT-1a exemplified in Patent Document 1 was used alone instead of the mixture of the exemplified compounds CT-1a and 1c. Got
A lot of crystals precipitated after the photoconductor coating. Attempts were made to measure the electrical characteristics of this photoreceptor, but no optical attenuation was observed, and the characteristics could not be measured.

(Comparative Example 2: Electrophotographic photoreceptor P2)
An electrophotographic photoreceptor P2 as a comparative example was obtained in the same manner as in Example 1 except that the charge transport material CT-1c was used alone instead of the mixture of the exemplified compounds CT-1a and 1c.
(Example 12: Electrophotographic photoreceptor B1)
100 parts by mass of polyarylate resin (B) having the following repeating structure (viscosity average molecular weight 43,000), 80 parts by mass of a mixture of CT-1a, CT-1b and CT-1c obtained in Production Example 1 as a charge transport material In addition, 8 parts by mass of a compound represented by the following formula (AOX1) as an antioxidant and 0.05 parts by mass of silicone oil as a leveling agent are dissolved in 640 parts by mass of a mixed solvent of THF / toluene (8/2 (weight ratio)). Then, a coating solution for forming a charge transport layer was prepared, and a photoreceptor sheet B1 was produced by the same production method as in Example 1.

(Examples 13 to 22: electrophotographic photoreceptors B2 to B11)
Electrophotographic photoreceptors B2 to B11 as examples were obtained in the same manner as in Example 12, except that a mixture of CT-1a and CT-1c was used as the charge transport material instead of the exemplified compounds CT-1a to c. It was. In the electrophotographic photoreceptor B11, crystal precipitation was observed, but electrical characteristics could be measured. The composition of the charge transport material is shown in Table 3.

(Comparative Example 3: Electrophotographic photoreceptor P3)
An electrophotographic photoreceptor P3 as a comparative example was prepared in the same manner as in Example 12 except that the charge transport material CT-1a exemplified in Patent Document 1 was used alone instead of the mixture of the exemplified compounds CT-1a and 1c. As a result, a lot of crystals were deposited after the photoconductor coating. Attempts were made to measure the electrical characteristics of this photoreceptor, but no optical attenuation was observed, and the characteristics could not be measured.

(Comparative Example 4: Electrophotographic photoreceptor P4)
An electrophotographic photoreceptor P2 as a comparative example was obtained in the same manner as in Example 12 except that the charge transport material CT-1c was used alone instead of the mixture of the exemplified compounds CT-1a and 1c.
(Example 23: electrophotographic photoreceptor C1)
Instead of the exemplified compounds CT-1a-c, except that 80 parts by mass of a mixture of CT-2a, CT-2b, CT-2c obtained in Production Example 3 was used as a charge transport material, the same as in Example 1, An electrophotographic photoreceptor C1 as an example was obtained. Table 4 shows the composition of the charge transport material.

(Examples 24-33: electrophotographic photoreceptors C2-C11)
Electrophotographic photoreceptors C2 to C11 as examples are obtained in the same manner as in Example 1 except that instead of the exemplified compounds CT-2a to c, a mixture of CT-2a and CT-2c is used as a charge transport material. It was. The composition of the charge transport material is shown in Table 4.
(Comparative Example 5: electrophotographic photoreceptor P5)
An electrophotographic photoreceptor P5 as a comparative example was obtained in the same manner as in Example 1 except that the charge transport material CT-2a was used alone instead of the mixture of the exemplified compounds CT-2a and 2c.

(Comparative Example 6: electrophotographic photoreceptor P6)
An electrophotographic photoreceptor P6 as a comparative example was obtained in the same manner as in Example 1 except that the charge transport material CT-2c was used alone instead of the mixture of the exemplified compounds CT-2a and 2c.
(Example 34: Electrophotographic photosensitive member D1)
Except for using 80 parts by mass of the mixture of CT-2a, CT-2b, and CT-2c obtained in Production Example 3 as the charge transport material, the electrophotographic photoreceptor D1 as an example was prepared in the same manner as in Example 12. Obtained. The composition of the charge transport material is shown in Table 5.

(Examples 35 to 44: electrophotographic photoreceptors D2 to D11)
Electrophotographic photoreceptors D2 to D11 as examples were obtained in the same manner as in Example 12, except that a mixture of CT-2a and CT-2c was used as the charge transport material instead of the exemplified compounds CT-2a to c. It was. The composition of the charge transport material is shown in Table 5.
(Comparative Example 7: electrophotographic photoreceptor P7)
An electrophotographic photoreceptor P7 as a comparative example was obtained in the same manner as in Example 12 except that the charge transport material CT-2a was used alone instead of the mixture of the exemplified compounds CT-2a and 2c.

(Comparative Example 8: electrophotographic photosensitive member P8)
An electrophotographic photoreceptor P8 as a comparative example was obtained in the same manner as in Example 12 except that the charge transport material CT-2c was used alone instead of the mixture of the exemplified compounds CT-2a and 2c.
(Example 45: Electrophotographic photoreceptor E1)
A mixture of the exemplified compounds CT-1a and CT-1c (CT-1a / CT-1c = 62/38) was used as the charge transport material, and a polycarbonate resin (E) having the following repeating structure was used as the binder resin. Except for the above, an electrophotographic photosensitive member E1 as an example was obtained in the same manner as in Example 1. The viscosity average molecular weight of the polycarbonate resin (E) was 50,000.

(Example 46: Electrophotographic photoreceptor E2)
Example 1 except that a mixture of the exemplified compounds CT-2a and CT-2c (CT-2a / CT-2c = 68/32) was used as the charge transport material and polycarbonate resin (E) was used as the binder resin In the same manner as described above, an electrophotographic photoreceptor E2 as an example was obtained.
(Example 47: electrophotographic photosensitive member K1)
A mixture of the exemplified compounds CT-1a and CT-1c (CT-1a / CT-1c = 62/38) was used as a charge transport material, and a polycarbonate resin (K) having the following repeating structure was used as a binder resin. Except for the above, an electrophotographic photosensitive member K1 as an example was obtained in the same manner as in Example 1. The viscosity average molecular weight of the polycarbonate resin (E) was 40,000.

(Example 48: Electrophotographic photosensitive member K2)
Example 1 except that a mixture of the exemplified compounds CT-2a and CT-2c (CT-2a / CT-2c = 68/32) was used as the charge transport material and polycarbonate resin (K) was used as the binder resin In the same manner as described above, an electrophotographic photosensitive member K2 as an example was obtained.
(Example 49: Electrophotographic photoreceptor M1)
Using a mixture of the exemplified compounds CT-1a and CT-1c (CT-1a / CT-1c = 62/38) as a charge transport material, 25 parts by mass of a polycarbonate resin (M) having the following repeating structure as a binder resin (Viscosity average molecular weight 40,000), polyarylate resin (B) 75 parts by mass (viscosity average molecular weight 43
, 000) was used in the same manner as in Example 12 to obtain an electrophotographic photosensitive member M1 as an example.

(Example 50: electrophotographic photosensitive member M2)
An electrophotographic photoreceptor as an example in the same manner as in Example 49 except that a mixture of the exemplified compounds CT-2a and CT-2c (CT-1a / CT-1c = 68/32) was used as the charge transport material. Obtained M2.
[Characteristic evaluation]
The following electrical property tests were performed on the produced electrophotographic photoreceptors A1 to A11, B1 to B11, C1 to C11, D1 to D11, E1 to E2, K1 to K2, M1 to M2, and P1 to P8.

<Electrical characteristics test>
An electrophotographic characteristic evaluation apparatus manufactured according to the electrophotographic society measurement standard (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404 to 405) is used, and the photoreceptor sheet has an outer diameter of 80 mm. After the aluminum drum and the aluminum substrate of the photosensitive sheet are connected to each other, the drum is rotated at a constant rotational speed of 60 rpm to charge, expose, measure potential, and remove static electricity. An electrical property evaluation test by cycle was performed. At that time, the photosensitive member was charged so that the initial surface potential was − (minus, the same applies hereinafter) to 700 V, and the light from the halogen lamp was converted to monochromatic light of 780 nm with an interference filter and exposed at 1.0 μJ / cm ² . The post-exposure surface potential after 100 milliseconds (hereinafter sometimes referred to as Vl) was measured. In measuring Vl, the time required from the exposure to the potential measurement was set to 100 ms, which was a fast response condition. Further, the photoreceptor surface potential is -700 V to -350.
The half exposure energy E1 / 2 (μJ / cm2) required to reach V was determined. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50%.

  The evaluation results of the electrophotographic photoreceptors A1 to A11, B1 to B11, C1 to C11, D1 to D11, E1 to E2, K1 to K2, M1 to M2, and P1 to P8 are shown in Tables 2 to 5.

* Crystals precipitated slightly.
** Since many crystals were precipitated, optical attenuation was hardly observed, and the characteristics could not be measured.

* Precipitation of crystals was observed.
** Since many crystals were precipitated, optical attenuation was hardly observed, and the characteristics could not be measured.
As shown in Tables 2 to 3, the electrophotographic photoreceptor using the known stilbene-based charge transport material CT-1a alone has poor compatibility with the binder resin, and crystals are deposited after coating, so that light attenuation is almost not observed. Although the properties were not measured and the properties were not measured, a photoreceptor using a mixture of methoxy group-substituted isomers of the stilbene charge transport material of the present invention represented by the general formula [1] is in a phase with a binder resin. It can be seen that it has good solubility and excellent electrical properties.

On the other hand, the photoconductor using the stilbene charge transport material CT-1c having an o-methoxy group alone has excellent photosensitivity, but the exposure potential Vl is methoxy group-substituted isomer of the stilbene charge transport material of the present invention. Higher than photoreceptors using a mixture of bodies. When these are compared, it can be seen that when the substituted isomer mixture is used, as shown in the examples, it is generally excellent in terms of electrical characteristics and compatibility.

As shown in Tables 4 to 5, the ethoxy group-substituted stilbene-based charge transporting substance CT-2a or CT-2c can be used alone as a charge transporting material, but each has a characteristic in terms of electrical characteristics. (CT-2a has a low exposure potential Vl and CT-2c has good photosensitivity), and a mixture of ethoxy group-substituted isomers of the stilbene charge transport material of the present invention represented by the general formula [1] is used. The photoconductors exhibit excellent electrical properties and are easy to manufacture because they can absorb or utilize the advantages of the respective charge transport materials. When these are compared, it can be seen that when the substituted isomer mixture is used, as shown in the examples, it is generally excellent in terms of electrical characteristics and compatibility.

As shown in Tables 6 to 8, the photoreceptor using the substituted isomer mixture of the stilbene-based charge transport material of the present invention represented by the general formula [1] is another known polycarbonate resin (E or K), Or the compatibility with the mixture of polycarbonate and polyarylate resin (M / B = 25/75) is very good.
It turns out that it is excellent in terms of electrical characteristics.
<Evaluation of ozone resistance>
The method of ozone exposure test is described below. Using EPA8200 manufactured by Kawaguchi Electric Co., Ltd., the photoconductors obtained in Examples A1 to A2, C1 to C2, Comparative Examples P1 to P2, and P5 to P6 were charged by applying a current of 25 μA to the corotron charger. The charge value was V1. Then, 150 ppm of ozone was exposed to these photoreceptors for 5 hours a day for 2 days (total exposure amount 750 ppm · hour), and the charge value was measured in the same manner after the exposure. This value was designated as V2. Table 3 shows the charge retention before and after ozone exposure [(V2 / V1) * 100] (%).
Similarly to the electrical property evaluation method described above, the residual potential before and after ozone exposure was measured 10 seconds after exposure (respectively Vr1 and Vr2), and the difference ΔVr (Vr2−Vr1) was determined and shown in Table 9. .

* Since many crystals were precipitated, the properties could not be measured.
As shown in Table 9, a photoconductor using a mixture of alkoxy group-substituted isomers of the stilbene charge transport material of the present invention is A1, A2, or C1, C2 is a single product of a charge transport material substituted with an alkoxy group. Compared with the existing photoreceptors P1, P2, or P5, P6, the charge retention before and after ozone exposure is high, and the difference in residual potential after 10 seconds of exposure is small. Therefore, an electrophotographic photoreceptor using a mixture of alkoxy group-substituted isomers of the stilbene charge transport material of the present invention has better ozone resistance than a photoreceptor using a single product of an alkoxy group-substituted charge transport material. It has been confirmed that the electrical stability is better.

<Image formation test and photoreceptor stability / durability test>
(Examples 51 to 57)
Charge generation produced in the same manner as the electrophotographic photoreceptors B1, B3, D1, D2, E2, K2, and M2 on an aluminum tube with a diameter of 3 cm and a length of 25.4 cm that has been anodized and sealed. The electrophotographic photosensitive drums N1 to N7 having a film thickness of 0.3 μm and a charge transport layer of 20 μm were applied to the layers and the charge transport layer coating solution by dip coating in order and dried. As each, it produced. These electrophotographic photosensitive drums were mounted on a laser printer, Laser Jet 4 (LJ4) manufactured by Hewlett-Packard Company, and an image test was performed. After the initial image was printed, 10,000 sheets were continuously printed, and the presence or absence of image deterioration in the solid portion and the halftone portion was visually observed. Table 10 shows the results.

(Comparative Examples 9 to 11)
In the procedure of Example 51, except that the charge transport layer coating solution was prepared in the same manner as the electrophotographic photoreceptors P4, P7, P8, in the same procedure as Example 51, as Comparative Examples 9-11, Electrophotographic photosensitive drums P9 to P11 were prepared and subjected to an image test. Table 10 shows the results.

* The following symbols indicate how image defects are observed when image evaluation is performed using the method specified above.
A: Good and no defects are visible.
○: Almost no defects are visible.
Δ: The defects are slightly visible.
X: Defects are clearly visible.

From Examples 51 to 57 and Comparative Examples 9 to 11, in the electrophotographic photosensitive member using a single product of alkoxy group-substituted stilbene-based charge transport material, image defects do not appear in the initial stage, but the characteristics during repeated use are sufficient. is not. On the other hand, an electrophotographic photoreceptor using a mixture of alkoxy group-substituted isomers of the stilbene-based charge transporting material represented by the formula [I] according to the present invention has no problem at all and has very good repetitive characteristics. It was confirmed.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. The electrophotographic photosensitive member and the image forming apparatus accompanying such changes are also within the technical scope of the present invention, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. Must be understood as encompassed by.

  The present invention can be carried out in any field that requires an electrophotographic photoreceptor, and is suitable for use in, for example, a copying machine, a printer, a printing machine, and the like.

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
DESCRIPTION OF SYMBOLS 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (5)

In an electrophotographic photoreceptor having a photosensitive layer on a conductive support, the photosensitive layer contains at least two Z group-substituted isomers of a stilbene compound having a structure represented by the following general formula [1]. An electrophotographic photosensitive member characterized by the above.

(In the above formula [1], Ar ¹ and Ar ² each represent an aryl group which may have an organic group having a substituent constant σp of 0.20 or less in Hammett's rule, and R represents a carbon number of 1 to 4 X and Y are the same or different, each having a substituent constant σp in the Hammett rule of 0.20 or less, an organic group having 1 to 4 carbon atoms, and m and n in the stilbene skeleton. Represents the number of substituents X and Y substituted on the benzene ring, and represents an integer of 0 to 4.) Two types of Z group-substituted isomers of the stilbene compound are substituted isomers in which the substitution position of the Z group represented by the following general formula [2] is ortho to the double bond substituent of the terminal phenyl group, and The electron according to claim 1, wherein the substitution position of the Z group represented by the following general formula [3] is two kinds of substituted isomers which are para to the double bond substituent of the terminal phenyl group. Photoconductor.

(In the above formula [2] or [3], Ar ¹ and Ar ² are the substituent constants σp in Hammett's rule, respectively.
Represents an aryl group which may have an organic group of 0.20 or less, and R represents an alkyl group having 1 to 4 carbon atoms. X and Y are the same or different, and the substituent constant σp in Hammett's rule is
Is an organic group having 1 to 4 carbon atoms, m and n represent the number of substituents X and Y substituted on the benzene ring in the stilbene skeleton, and represent an integer of 0 to 4 . )   The ratio of the ortho-position Z group-substituted isomer of the stilbene compound represented by the general formula [2] to the para-position Z group-substituted isomer of the stilbene compound represented by the general formula [3] is 90/10 to 10 3. The electrophotographic photosensitive member according to claim 2, wherein the electrophotographic photosensitive member is / 90.   The electrophotographic photosensitive member according to claim 1, a charging means for charging the electrophotographic photosensitive member, an image exposure means for forming an electrostatic latent image on the charged electrophotographic photosensitive member by image exposure, the static At least one means selected from a developing means for developing an electrostatic latent image with toner, a transfer means for transferring the toner to a transfer target, and a cleaning means for collecting the toner adhering to the electrophotographic photosensitive member. Electrophotographic cartridge. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member, and the electrostatic An image forming apparatus comprising: a developing unit that develops a latent image with toner; a transfer unit that transfers the toner to a transfer target; and a fixing unit that fixes the toner transferred to the transfer target. .

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