JP6387649B2 - Electrophotographic photosensitive member, electrophotographic photosensitive member cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member containing a novel butadiene compound suitably used as an electron transport material for an electrophotographic photosensitive member in a photosensitive layer, an electrophotographic cartridge using the electrophotographic photosensitive member, and an image forming apparatus. This electrophotographic photosensitive member has a characteristic that, when it is a positive charging process and has a single layer type photosensitive member structure, it has good electric characteristics, and when it is repeatedly used, it does not easily cause a decrease in photosensitivity, an increase in residual potential, etc. .

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").
With the recent increase in the speed and image quality of the electrophotographic process, a photoreceptor containing an electron transport material is attracting attention. In particular, positively charged photoreceptors (so-called “positively charged single-layer photoreceptors”) containing an electron transporting material and a hole transporting material in the same photosensitive layer have been actively studied (see Patent Documents 1 and 2). . Such a photoreceptor is superior in reproducibility of electrostatic latent images because the charge generation position is near the surface and the moving distance of the negative charge moving to the surface is short compared to the conventional negatively charged laminated photoreceptor. Yes. Further, it is recognized that the positively charged photoreceptor has much less ozone generation in the charging process than the negatively charged photoreceptor, has excellent oxidation resistance degradation performance, has a long life, and is friendly to the environment. In addition, the single layer structure has the advantage that the manufacturing process can be simplified compared to the laminated type, and is said to be very attractive as a photoreceptor for the next household. On the other hand, the electron transport material essential for positively charged single-layer type photoreceptors is much harder to achieve higher performance than the positively charged hole transport material, so there are not many newly developed products on the market. This is a bottleneck in the full-scale spread of electrophotographic equipment.
As a conventional technique, it is known that a compound in which a substituent capable of transporting electrons is introduced into various π-electron conjugated systems can be used as an electron transfer material for a positively charged single layer type electrophotographic photosensitive member. For example, it has been proposed that a compound in which a cyano group or an ester group is introduced at the end of a butadiene conjugated skeleton as described in Patent Document 3 can be used as an electron transport material.

However, when the compound group described in Patent Document 3 is used for a positively charged single-layer type photoreceptor, basic performance such as photosensitivity, residual potential, and chargeability is extremely poor, so it has not been put to practical use. Is the actual situation.

JP 2002-258502 A JP 2001-312075 Patent Publication No. 2991150

  The present invention has been made in view of such a current situation, and the object thereof can be put to practical use by using a butadiene-based compound having a relatively good electron transport ability for a positively charged single layer type electrophotographic photosensitive member. Another object of the present invention is to provide a photosensitive member, an electrophotographic cartridge containing the photosensitive member and an image forming apparatus.

As a result of diligent studies to solve the above problems, the present inventor has a relatively good electrical property, in which a photoreceptor using a compound in which a specific electron-withdrawing substituent is introduced into a butadiene conjugated skeleton as an electron transporting material, The positively charged single layer type electrophotographic cartridge and the image forming apparatus containing the electron transport material were found to have good performance, and the present invention was completed.
That is, the first gist of the present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive support, and a butadiene-based compound having a structure represented by the following general formula [1] in the photosensitive layer. ,
The electrophotographic photosensitive member is characterized by containing at least one kind (claim 1).

(In the above formula [1], Ar ¹ and Ar ² are the same or different and each has at least one Hammett.
an aryl group having an alkyl group or a carbonyl group having a substituent constant σp in the t-rule of 0.30 or more, and A and B are the same or different and each is a halogen atom, an organic group having a halogen atom, a cyano group, a cyano group An organic group having nitro group, an organic group having nitro group,
Sulfonyl group, an organic group having a sulfonyl group, at least one selected from an organic group having an organic group or a ketone structure, having an ester structure. )
The second gist of the present invention resides in the electrophotographic photosensitive member according to claim 1, wherein a positive charging process is taken as a charging means, and the photosensitive layer has a single-layer structure (claim 2).

The third gist of the present invention is the electrophotography according to claim 1 or 2, wherein in the general formula [1], Ar ¹ and Ar ² are each an aryl group having a fluorine-substituted alkyl group. It exists in the photoreceptor (claim 3).
The fourth gist of the present invention is characterized in that, in the general formula [1], A and B are each at least one selected from a cyano group or an organic group having a sulfonyl group. The present invention resides in the electrophotographic photosensitive member according to any one of the above (claim 4).

  According to a fifth aspect of the present invention, there is provided the electrophotographic photosensitive member, a charging unit for charging the electrophotographic photosensitive member, and an image exposing unit for performing image exposure on the charged electrophotographic photosensitive member to form an electrostatic latent image. 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 an electrophotographic photosensitive member. An electrophotographic cartridge having at least one selected from cleaning means for collecting the adhered toner using a cleaning blade.

  According to a sixth aspect of the present invention, there is provided the electrophotographic photosensitive member, a charging unit for charging the electrophotographic photosensitive member, and an exposing unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. The image forming apparatus includes: a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the toner to a transfer target.

  By using the butadiene-based electron transport material of the present invention for a photoreceptor, electrical characteristics such as photosensitivity, residual potential, and chargeability are improved as compared with conventional ones. Further, when the electrophotographic photosensitive member of the present invention is used in a positively charged single layer type, it is possible to provide an electrophotographic cartridge and an image forming apparatus with clear image quality and good reproducibility.

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. 2 is a nuclear magnetic resonance spectrum of exemplary compound ET-1 obtained in Production Example 1. 2 is a nuclear magnetic resonance spectrum of exemplary compound ET-2 obtained in Production Example 2.

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.
《Butadiene compound》
In the present invention, the butadiene compound contained in the photosensitive layer of the electrophotographic photosensitive member as the electron transporting material has a structure represented by the following general formula [1].

(In the above formula [1], Ar ¹ and Ar ² are the same or different and each represents an aryl group having at least one alkyl group or carbonyl group having a substituent constant σp of 0 or more in Hammett's rule, A and B are the same or different and each represents an organic group having at least one selected from a halogen atom, a cyano group, a nitro group, a sulfonyl group, an ester structure, or a ketone structure.
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 / This can be said to be 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 having at least one alkyl group or carbonyl group having a substituent constant σp of 0 or more in Hammett's rule. The value of the substituent constant σp in the Hammett rule is preferably 0.00 or more, more preferably 0.30 or more, and particularly preferably 0.45 or more from the viewpoint of electrical characteristics. On the other hand, the upper limit is preferably 0.8 or less from the viewpoint of trapping electrons to form a stable structure and preventing charge transport from being inhibited. Examples of the alkyl group having a substituent constant σp of 0 or more include fluorine-substituted alkyl groups such as a trifluoromethyl group, a pentafluoroethyl group, and a tetrafluoropropyl group, and the carbonyl group includes methoxycarbonyl And an ester structure such as an ethoxycarbonyl group, or a ketone structure such as an acetyl group, a propionyl group, or a benzoyl group. Among them, a fluorine-substituted alkyl group, an acetyl group, or a benzoyl group is preferable from the viewpoint of compatibility of electrical characteristics of the compound and safety during production, and a fluorine-substituted alkyl group is preferable from the viewpoint of production cost, and particularly a trifluoromethyl group is preferable. preferable.

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

In the above formula [1], A and B are the same or different and include an organic group having at least one selected from a halogen atom, a cyano group, a nitro group, a sulfonyl group, an ester structure, or a ketone structure, Any combination of them may be used as long as it becomes the end of the butadiene structure via a double bond. As a specific example, for example, the following combinations can be used. Of these, structures having an organic group having a cyano group or a sulfonyl group (EWG1 to 3) are particularly preferable from the viewpoints of electrical characteristics and production costs.

  As typical examples of the butadiene-based compound represented by the formula [1], there may be mentioned the following exemplified compounds ET-1 to ET-12. However, the butadiene compound related to the present invention is not limited to these compounds.

These butadiene compounds can be easily synthesized by known methods. For example, exemplary compound ET-1 of the present invention can be produced according to the following reaction formula.

First, the benzophenone derivative C is reacted with the Witting reagent D and further hydrolyzed under acidic conditions to obtain the cinnamylaldehyde derivative E. Next, if E and malononitrile are condensed in the presence of piperidine, the target ET-1 can be obtained.
≪Electrophotographic photoreceptor≫
[Conductive support]
As the conductive support, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, nickel or the like, a resin material or aluminum provided with conductivity by adding conductive powder such as metal, carbon, tin oxide, Mainly used are resin, glass, paper, or the like, on which a conductive material such as nickel or ITO (indium tin oxide alloy) is deposited or coated. As a form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material in order to control conductivity and surface properties or to cover defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after an anodized film is applied. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
For example, an anodic oxidation film is formed by anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, etc. give. In the case of anodic oxidation in sulfuric acid, the sulfuric acid concentration is 100 to 300 g / l, the dissolved aluminum concentration is 2 to 15 g / l, the liquid temperature is 15 to 30 ° C., the electrolysis voltage is 10 to 20 V, and the current density is 0.5 to Although it is preferable to set within the range of 2A / dL2, it is not limited to the said conditions.

It is preferable to perform a sealing treatment on the anodic oxide film thus formed. The sealing treatment may be performed by a known method. For example, it is immersed in an aqueous solution containing nickel fluoride as a main component, or immersed in an aqueous solution containing nickel acetate as a main component. A high temperature sealing treatment is preferably performed.
The surface of the 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 diameter with the material constituting the support.
An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties.

<Underlayer>
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.

  As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used. 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. Only one type of particle may be used, or a plurality of types 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 silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystalline state may be contained.

In addition, various particle sizes of metal oxide particles can be used. Among them, from the viewpoint of characteristics and liquid stability, the average temporary particle size is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm or more. 50 nm or less.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As the binder resin used for the undercoat layer, phenoxy resin, epoxy resin, polyvinylpyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are cured alone or with a curing agent. Of these, alcohol-soluble copolymer polyamides and modified polyamides are preferable because they exhibit good dispersibility and coatability. In addition, the binder resin of an undercoat layer may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. Further, the binder resin can be used only in the binder resin or in a form cured with a curing agent.

In addition, when the photosensitive layer of the photosensitive member of the present invention is a single layer type, the adhesion to the support is low, and the photosensitive layer may be peeled off during use. It can also be used as a substitute for the undercoat layer. In this case, an undercoat layer in which a phthalocyanine pigment or an azo pigment is dispersed and applied in a binder resin is preferably used. Thus, when the charge generation layer is used as a substitute for the undercoat layer, the electrical characteristics are particularly excellent, which is preferable.

[Photosensitive layer]
The photoreceptor of the present invention has a photosensitive layer on a conductive support.
The photosensitive layer of the electrophotographic photoreceptor is a multilayer photoreceptor having a multilayer photosensitive layer including a charge generation layer (a layer containing a charge generation material) and a charge transport layer (a layer containing a charge transport material), or a charge generation material And a single-layer type photoreceptor containing a charge transporting material in the same photosensitive layer. In the present invention, the structure is not particularly limited as long as it is a photosensitive layer containing a butadiene-based compound represented by the above formula [1], but a single-layer type photoreceptor is particularly preferable.
First, components of the photosensitive layer will be described.

<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, polycarbonate IN, 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, etc. -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 mass parts, 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. When the ratio of the charge generating substance is too high, there are problems such as a decrease in chargeability, a decrease in sensitivity, and a decrease in smoothness due to aggregation. On the other hand, if the ratio of the charge generating material is too low, the sensitivity of the photoreceptor may be lowered.
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 butadiene-based electron transport material represented by the formula [1] of the present invention, and usually contains a binder resin and other components used as necessary. contains. 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 transporting material, it is preferable to use the electron transporting butadiene-based compound of the present invention, and the same one may be used alone, or a plurality of types may be combined at an arbitrary ratio.
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.

  Specific examples of suitable structural units of the binder resin are shown below. These specific examples are shown for illustration, and any known binder resin may be mixed and used as long as it does not contradict the gist of the present invention.

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 photoconductor, 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 charge transport material of the single-layer type photosensitive layer usually contains both a hole transport charge transport material and an electron transport charge transport material. Therefore, as a kind of embodiment of the present invention, other known charge transport materials may be used in combination with the butadiene-based electron transport material of the present invention. When other charge transport materials are used in combination, the type is not particularly limited, but examples of hole transport charge transport materials include enamine derivatives, carbazole derivatives, hydrazone compounds, aromatic amine derivatives, butadiene derivatives, stilbene derivatives, and the like. Those in which a plurality of derivatives are bonded are preferable. More specifically, JP-A-2009-020504, JP-A-2-230255, JP-A-63-225660, JP-A-58-198043, JP-B-58-32372, and JP-B-7-21646. The compounds described in the publications are preferably used. Any one of these hole transporting charge transport materials may be used alone, or a plurality of these may be used in any combination.

  Specific examples of suitable structures of the hole transporting charge transporting material are shown below. These specific examples are shown for illustration, and any known hole transporting charge transporting material may be used as long as it does not contradict the gist of the present invention.

  When the butadiene-based electron transport compound of the present invention is used in combination with a known hole transport charge transport material, the content ratio (% by mass) of the hole transport charge transport material to be used in the total amount of the charge transport material is: Although not particularly limited, it is usually preferably in the range of 10% or more and 90% or less, more preferably in the range of 20% or more and 80% or less in terms of electrical characteristics, and the electron transporting compound of the present invention. In order to exhibit the role more effectively, it is particularly preferably in the range of 30% to 60%.

Further, as an electron transporting charge transporting material that can be used in combination with the butadiene compound of the present invention, for example, a diphenoquinone derivative, a dinaphthoquinone derivative, an indandinone derivative, a dicyannovinyl derivative, a 1,3,5-triazine derivative, a naphthalene didecanoic acid diamide derivative Etc. Any one of these electron transporting charge transport materials may be used alone, or a plurality of these materials may be used in any combination.

  Specific examples of suitable structures of the electron transporting charge transporting material are shown below. These specific examples are shown for illustration, and any known electron transporting charge transporting material may be used as long as it is not contrary to the gist of the present invention.

When the butadiene compound of the present invention and a known electron transporting charge transport material are used in combination, the content ratio (% by mass) of the electron transporting charge transporting material to be used in the total amount of the electron transporting charge transporting material is particularly limited. However, it is preferably within a range of 30% or less, and particularly preferably within a range of 15% or less in order to more effectively exhibit the role of the electron transporting compound of the present invention.

The kind of the binder resin and the use ratio with the charge transport material 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 due to aggregation. The total amount is generally 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, based on the entire monolayer type photosensitive layer.
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 components and 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. Known antioxidants,
You may contain additives, such as a plasticizer, a ultraviolet absorber, an electron withdrawing compound, a leveling agent, and a visible light shading agent.

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.
These protective layers contain at least the butadiene-based electron transport material represented by the general formula [1]. Moreover, you may add an additive suitably to the said protective layer in the range which does not impair hardness and an elastic deformation rate. Examples thereof include resin particles such as fluorine resin, silicon resin, and cross-linked polystyrene resin, and inorganic particles such as alumina particles and silica particles. Further, when the thickness of the protective layer is greater than 1 μm, the physical properties of the protective layer dominate the surface mechanical properties more than the influence of the lower layer. Therefore, the material used for the lower photosensitive layer is within the range specified in the present invention. Any material may be used without being limited to the above.

As the conductive material used for the protective layer, in addition to the butadiene-based electron transport material of the present invention, diphenoquinone derivatives, dinaphthoquinone derivatives, indandinone derivatives, dicyannovinyl derivatives, 1,3,5-triazine derivatives, naphthalenedican sulfonic acid diamide derivatives, etc. Other electron transport materials can also be used. In addition, metal oxides such as antimony oxide, indium oxide, tin oxide, titanium oxide, 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, 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, Chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-
Chlorinated hydrocarbons such as dichloropropane and trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine and triethylenediamine, acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide, Examples include aprotic polar solvents such as dimethyl sulfoxide. 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.

[Photoconductor charging type]
The photoconductor of the present invention is preferably used as a single layer type photoconductor, so that it is more effective to use it with positive charge.

[Exposure wavelength of photoconductor]
When forming an image, the photosensitive member of the present invention is exposed to writing light from an exposure unit to form an electrostatic latent image. The writing light used at this time is arbitrary as long as an electrostatic latent image can be formed. Among them, monochromatic light having an exposure wavelength of usually 380 nm or more, particularly 400 nm or more, and usually 850 nm or less is used. In particular, when monochromatic light of 480 nm or less is used, the photoconductor can be exposed with light having a smaller spot size, and a high-quality image having high resolution and high gradation can be formed. When it is desired to obtain the light, exposure with monochromatic light of 480 nm or less is preferable.

≪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. As the upper and lower fixing members 71 and 72, a known heat fixing member 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 resin is coated, or a fixing sheet is used. be able to. 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 synthesis 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.
<Production of butadiene-based compounds>
(Production Example 1: Production of exemplary compound ET-1)
[Scheme 1]

Under a nitrogen atmosphere, 6.36 g (20 mmol) of compound (C), 9.44 g (22 mmol) of compound (D) and 50 ml of tetrahydrofuran (hereinafter referred to as “THF”) were charged into a reactor, and potassium-tert -2.69 g (24 mmol) of butoxide was added slowly. Then, continue stirring,
The reaction was allowed to proceed for 1 hour at room temperature. After completion of the reaction, the mixture was cooled, and 50 ml of toluene and 50 ml of water were added to separate the layers. The organic layer was washed 3 times with 50 ml / water, dried by contact with magnesium sulfate, and concentrated under reduced pressure. The obtained red oil was dissolved in 50 ml of THF, 10 ml of 1 mol / l hydrochloric acid was added, the temperature was further raised to 65 ° C., and the mixture was reacted for 1 hour. After completion of the reaction, the mixture was cooled, and 50 ml of toluene and 50 ml of water were added to separate the layers. The organic layer was washed 3 times with 1% aqueous sodium bicarbonate solution (50 ml / times), contacted with magnesium sulfate, dried, and concentrated under reduced pressure to give an oil. This crude product was dissolved in toluene and passed through column chromatography (silica gel 250 g, developing solvent: toluene) to obtain the aldehyde compound (E) as a yellow oil (6.06 g, yield 88%).

Under a nitrogen atmosphere, 4.13 g (12 mmol) of aldehyde compound (E), 0.95 g (14.4 mmol) of malononitrile, 0.5 ml of piperidine, and 50 ml of 95% ethanol were charged into the reactor and reacted for 2 hours while heating under reflux. After completion of the reaction, the reaction mixture was cooled to 0-5 ° C. with ice water, and the precipitated yellow solid was separated by filtration. This crude product was dissolved in toluene and passed through column chromatography (silica gel 200 g, developing solvent: toluene) to give the exemplified compound (ET-1) of the present invention as yellow crystals (3.92 g, yield 83%). . A nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer) of this compound is shown in FIG.

(Production Example 2: Production of exemplary compound ET-2)
[Scheme 2]

In a nitrogen atmosphere, aldehyde compound (E) 4.13 g (12 mmol), compound (K) 2.39 g (13.2 mmol), piperidine 0.5 ml, 95% ethanol 50 ml were charged into a reactor and heated under reflux.
Reacted for hours. After completion of the reaction, the reaction mixture was cooled to 0-5 ° C. with ice water, and the precipitated yellow solid was separated by filtration. This crude product was dissolved in toluene and passed through column chromatography (silica gel 200 g, developing solvent: toluene) to give the exemplified compound (ET-2) of the present invention as yellow crystals (4.93 g, yield 81%). . The nuclear magnetic resonance spectrum (300 MHz, Varian Gemini-2000 NMR spectrometer) of this compound is shown in FIG.

<Production of electrophotographic photoreceptor>
(Example 1: Electrophotographic photoreceptor A1)
First, the undercoat layer dispersion was prepared by the following method.
A rutile type titanium oxide with an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) based on the titanium oxide Disperse the surface-treated titanium oxide obtained by mixing in a mixing and kneading machine (“SMG300” manufactured by Kawata Co., Ltd.) and mixing at high speed at a rotational peripheral speed of 34.5 m / sec using a ball mill of methanol / 1-propanol. 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 [following formula The compound represented by (J)] has a composition molar ratio of 60% / 15% / 5% / 15% / 5% and is agitated and mixed with pellets of copolymerized polyamide to dissolve the polyamide pellets. Then, by carrying out ultrasonic dispersion treatment, the mass ratio of methanol / 1-propanol / toluene is 7/1/2 and the hydrophobically treated titanium oxide / copolymerized polyamide is contained at a mass ratio of 3/1. Solid content concentration A coating solution for forming an undercoat layer of 18.0% was prepared.

The photosensitive layer forming coating solution was prepared as follows.
First, as a charge generation material, 20 parts of oxytitanium phthalocyanine and 280 parts of 1,2-dimethoxyethane showing the X-ray diffraction spectrum by CuKα characteristic X-ray in FIG. 2 are mixed and pulverized in a sand grind mill for 1 hour to make fine particles Distributed processing was performed. Subsequently, 10 parts of polyvinyl butyral (trade name “Denka Butyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl. A binder liquid obtained by dissolving in 85 parts of 2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution for forming a charge generating material.

  Next, 30 parts by mass of the butadiene-based electron transport material (ET-1) of the present invention, 60 parts by mass of the following compound (M) as a hole transport material, and 8 parts by mass of a compound (AOX1) represented by the following formula as an antioxidant 100 parts by weight of the polycarbonate resin (B-3) and 0.05 parts by weight of silicone oil as a leveling agent were mixed with 640 parts by weight of a mixed solvent of tetrahydrofuran and toluene (80% by weight of tetrahydrofuran, 20% by weight of toluene) to obtain a charge. A coating material for forming a transport material was prepared. The viscosity average molecular weight of the polycarbonate resin B-3 was 40,000.

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
The charge generation material forming coating solution and the charge transporting material forming coating solution obtained by the above method were mixed and dispersed uniformly by a homogenizer to obtain a photosensitive layer forming coating solution.

<Manufacture of photoconductor>
The above coating solution for forming the undercoat layer and the coating solution for forming the photosensitive layer are placed on an aluminum cylinder having an outer diameter of 30 mm, a length of 260.5 mm, and a wall thickness of 0.75 mm that has been mirror-finished and cleaned. Undercoat layer and photosensitive layer were formed so that the film thickness after drying was sequentially applied and dried by a dip coating method so that the film thickness after drying was 1.3 μm and 25 μm, respectively, to obtain a photoreceptor drum A1. The photosensitive layer was dried at 125 ° C. for 20 minutes.

(Example 2: electrophotographic photoreceptor A2)
An electrophotographic photosensitive drum A2 as Example 2 was obtained in the same manner as in Example 1 except that ET-2 was used as the electron transport material instead of the exemplified compound ET-1.
(Comparative Example 1: Electrophotographic photoreceptor P1)
An electrophotographic photosensitive drum P1 as a comparative example was obtained in the same manner as in Example 1 except that the electron transport material ET-13 exemplified in Patent Document 3 was used instead of the exemplified compound ET-1.

(Comparative Example 2: Electrophotographic photoreceptor P2)
An electrophotographic photosensitive drum P2 as a comparative example was obtained in the same manner as in Example 1 except that the electron transport material ET-14 exemplified in Patent Document 3 was used in place of the exemplified compound ET-1.

(Comparative Example 3: Electrophotographic photoreceptor P3)
Except for using the electron transport material ET-15 exemplified in Patent Document 3 instead of the exemplified compound ET-1,
In the same manner as in Example 1, an electrophotographic photosensitive drum P3 as a comparative example was obtained.

(Comparative Example 4: Electrophotographic photoreceptor P4)
An electrophotographic photosensitive drum P4 as a comparative example was obtained in the same manner as in Example 1 except that the electron transport material ET-16 exemplified in Patent Document 3 was used in place of the exemplified compound ET-1.

(Comparative Example 5: electrophotographic photoreceptor P5)
An electrophotographic photosensitive drum P5 as a comparative example was obtained in the same manner as in Example 1 except that the electron transport material ET-17 exemplified in Patent Document 3 was used in place of the exemplified compound ET-1.

<Electrical characteristics test>
Using the electrophotographic characteristic evaluation apparatus manufactured in accordance with the electrophotographic society measurement standard ("Continuing Electrophotographic Technology Basics and Applications", edited by the Electrophotographic Society, published by Corona 1996, pages 404-405) The photosensitive drums of the example and the comparative example were rotated at a constant rotation number of 60 pm, and an electrical property evaluation test was performed by a cycle of charging, exposure, potential measurement, and static elimination. At that time, the initial surface potential is charged to +700 V, and the light of the halogen lamp is changed to a monochromatic light of 780 nm by an interference filter, and the amount of surface potential is changed by using an ND filter having a different transmittance. The decay behavior was measured. The measured value, the exposure amount necessary for the surface potential to decrease by half (drops + 350 V) (half decay _exposure: referred to as _{E 1/2),} and 780nm of the monochromatic light was exposed in 1.0μJ / cm ² Each surface potential (bright potential: referred to as Vl) was read, and the results are shown in Table 2. In the above measurement, the time required from the exposure to the potential measurement was 100 ms, and the measurement environment was a temperature of 25 ° C. and a relative humidity of 50%.

<Image evaluation test>
The photosensitive drums of the above examples and comparative examples are mounted on a drum cartridge (DR510) of a commercially available laser printer HL-5140 (manufactured by Brother) that is used for positive charging, and a halftone image is output. The density difference from the image using the “DR510 genuine” and the presence or absence of black spots were confirmed. The image density is indicated as “dark”, “good”, “thin”, “very thin”, and “not observed” when no image appears, and “black spot” is indicated only when a black spot occurs. There was no photoreceptor with a “dark” image.

As shown in Table 2 above, when the butadiene electron transport material ET-1 or ET-2 of the present invention is used for a positively charged single layer type photoreceptor, the electrical characteristics of the photoreceptor are good, and the image Also in the characteristics, there were no defects such as density defects and black spots (Examples 1 and 2).
On the other hand, when the compounds ET-13 to ET-17 outside the scope of the present invention were used for the positively charged single-layer type photoreceptor as the electron transport agent, the electrical characteristics were severely deteriorated (Comparative Examples 1 to 5, especially the comparison). Examples 2 and 3). In terms of image characteristics, the image density may be poor (Comparative Example 1, Comparative Examples 4 and 5), or no image may appear (Comparative Examples 2 and 3), and black spots may occur (Comparative Example 2). 3 and Comparative Example 5). In particular, in Comparative Examples 2 and 3, only black spots were observed in the image situation.

  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 (6)

An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains at least one butadiene compound having a structure represented by the following general formula [1]. , Electrophotographic photoreceptor.

(In the above formula [1], Ar ¹ and Ar ² are the same or different and each has at least one Hammett.
an aryl group having an alkyl group or a carbonyl group having a substituent constant σp in the t-rule of 0.30 or more, and A and B are the same or different and each is a halogen atom, an organic group having a halogen atom, a cyano group, a cyano group An organic group having nitro group, an organic group having nitro group,
Sulfonyl group, an organic group having a sulfonyl group, at least one selected from an organic group having an organic group or a ketone structure, having an ester structure. ) 2. The electrophotographic photosensitive member according to claim 1, wherein a positive charging process is used as charging means, and the photosensitive layer has a single-layer structure. 3. The electrophotographic photosensitive member according to claim ¹ , wherein Ar ¹ and Ar ² in the general formula [1] are each an aryl group having a fluorine-substituted alkyl group. The electron according to any one of claims 1 to 3, wherein in the general formula [1], A and B are each at least one selected from a cyano group or an organic group having a sulfonyl group. Photoconductor. 5. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and image exposure is performed on the charged electrophotographic photosensitive member to form an electrostatic latent image. Image exposing means, developing means for developing the electrostatic latent image with toner, transfer means for transferring the toner to the transfer target, fixing means for fixing the toner transferred to the transfer target, and the electrophotography An electrophotographic cartridge comprising: at least one selected from cleaning means for recovering the toner adhering to the photoreceptor using a cleaning blade. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. An image forming apparatus comprising: an exposure unit; a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the toner to a transfer target.

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