JP2011112931A - Method for manufacturing electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophotographic photoreceptor having proper adhesiveness, the electrophotographic photoreceptor having a base coat layer formed of an aqueous dispersed coating liquid for the base coat layer, containing water-insoluble thermoplastic resin particles and metal oxide particles. <P>SOLUTION: The base coat layer is formed, by applying the following aqueous dispersion coating liquid for the base coat layer containing thermoplastic resin particles and metal oxide particles, and heating the coating film to melt the thermoplastic resin particles, when the volume particle size distribution of the thermoplastic resin particles in the aqueous dispersion coating liquid for the base coat layer, a particle size dispersion coefficient ε defined by ε=(D90-D10)/D50 is set at 0.2 or more and 1.0 or less, where D10, D50 and D90 represent the particle diameters corresponding to the 10% volume, 50% volume and 90% volume, respectively, of the distribution, and the metal oxide particles have a primary particle diameter of not more than 0.5 time that of D50. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing an electrophotographic photoreceptor. More specifically, the present invention relates to a method for producing an electrophotographic photoreceptor using an aqueous dispersion subbing layer coating solution containing thermoplastic resin particles having a specific particle size distribution and metal oxide particles.

An electrophotographic photoreceptor (hereinafter, simply referred to as “photoreceptor” in some cases) basically includes a photosensitive layer that forms a latent image by charging and exposure using light, and a support for providing the photosensitive layer. There is a conductive support. In order to prevent charge injection from the support to the photosensitive layer, a layer called an undercoat layer (sometimes called an intermediate layer) is provided between the photosensitive layer and the support.
If the electrical resistance of the undercoat layer is too high, the charge generated in the photosensitive layer does not escape to the support and stays in the photosensitive layer, resulting in an increase in residual potential and potential fluctuation due to repeated use.

On the other hand, an electrical blocking function is also required so that charges are not injected from the support to the photosensitive layer when a voltage is applied to the electrophotographic photoreceptor. This is because when charge is injected from the support, the charging performance and image contrast are lowered, and in the case of the reversal development method, black spots and fogging are caused on a white background, thereby degrading image quality. Also, in response to the recent demand for higher image quality, it is effective to reduce the thickness of the photoreceptor. However, reducing the thickness of the photosensitive layer is advantageous for improving the image quality, but promotes the injection of charges from the support. Therefore, it was necessary to further enhance the blocking function while maintaining the electrical resistance characteristics.
There is a need for an undercoat layer having an appropriate range of electrical resistance characteristics and a blocking function that satisfies these characteristics. Among them, an undercoat layer (Patent Document 1) containing a metal oxide such as tin oxide or titanium oxide in a resin has been studied. The subbing layer containing a resin and a metal oxide can suppress the retention of charge inside the photosensitive layer by increasing the content of the metal oxide even in a resin having a high electrical resistance.

However, if the content of the metal oxide is too large, there is a problem that sufficient adhesion required for the undercoat layer as a photoreceptor cannot be obtained. Further, since the surface roughness is increased, the blocking function is not sufficient, and in the case of the charging ability, the image contrast, and the reversal development method, black spots and fogging may occur on a white background.
Patent Document 2 discloses that an antistatic film having good water resistance, transparency, and adhesion to a substrate film can be obtained by drying a polyolefin resin aqueous dispersion excellent in liquid stability containing metal oxide particles. It is described. There was no problem in resolving power even when the undercoat layer was formed using a conventional aqueous dispersion coating solution to produce a photoreceptor. However, when the content of the metal oxide is increased, the adhesion of the photoreceptor is still insufficient. Therefore, the photosensitive layer may be peeled off due to repeated use over a long period of time.

JP-A-56-52757 JP 2003-268164 A

  It is an object of the present invention to provide an aqueous dispersion undercoating layer coating solution for forming an undercoating layer, which is suitable as a photoconductor in a method for producing an electrophotographic photosensitive member containing thermoplastic resin particles and metal oxide particles insoluble in water. Another object of the present invention is to provide a production method capable of obtaining the adhesion of the undercoat layer.

  The present invention has an undercoating layer and a photosensitive layer on a support, and an aqueous dispersion undercoating layer coating solution applied to form the undercoating layer is water-insoluble thermoplastic resin particles and metal oxide. An electrophotographic photosensitive member having a volume ratio of the metal oxide particles to the thermoplastic resin particles of 0.5 to 2.0 times, and the aqueous dispersion of the thermoplastic resin particles When the particle size distribution in the undercoat layer coating liquid is 10%, 50%, and 90% of the particle sizes corresponding to D10, D50, and D90, respectively, and the particle size dispersion coefficient ε = (D90−D10) / D50 The aqueous dispersion subbing layer coating solution having a particle size dispersion coefficient ε of 0.2 to 1.0 and a primary particle size of the metal oxide particles being 0.5 times or less of the D50 is applied. After forming the film, the coating film is heated to melt the thermoplastic resin particles to form an undercoat layer. The present invention relates to a method for producing an electrophotographic photosensitive member.

  According to the present invention, the adhesion between the photosensitive layer and the support is particularly excellent, the potential fluctuation due to repeated use is small, and a sufficient contrast potential can be obtained in any environment of high temperature and high humidity and low temperature and low humidity. It is possible to provide a method for producing an electrophotographic photosensitive member in which fog does not occur.

The present invention is described in detail below.
The aqueous dispersion subbing layer coating liquid of the present invention refers to a liquid in which thermoplastic resin particles and metal oxide particles are dispersed in a solvent having a water ratio of 50% by mass or more based on the total amount of the solvent.
In order to obtain particularly good adhesion of the undercoat layer under conditions within a certain range, the particle size dispersion coefficient of the thermoplastic resin particles in the aqueous dispersion undercoat layer coating solution must be within a certain range. The present invention has been found and has been accomplished.

  That is, the method for producing an electrophotographic photosensitive member of the present invention includes an undercoat layer and a photosensitive layer on a support, and the aqueous dispersion undercoat layer coating solution applied to form the undercoat layer is water. In the method for producing an electrophotographic photosensitive member, which contains insoluble thermoplastic resin particles and metal oxide particles, and the volume ratio of the metal oxide particles to the thermoplastic resin particles is 0.5 to 2.0 times, the thermoplastic resin The particle size distribution corresponding to 10%, 50%, and 90% volume of the particle size distribution in the aqueous dispersion subbing layer coating solution of particles is D10, D50, and D90, respectively, and the particle size dispersion coefficient ε = (D90−D10) / When D50, an aqueous dispersion subbing layer coating solution having a particle size dispersion coefficient ε of 0.2 to 1.0 and a primary particle size of metal oxide particles of 0.5 times or less of D50 is applied. After forming the coating film, the coating film is heated to melt the thermoplastic resin particles and subbing. A layer is formed.

  When the undercoat layer coating liquid contains thermoplastic resin particles and metal oxide particles, the volume ratio of the metal oxide particles to the thermoplastic resin particles needs to be 0.5 to 2.0 times. If it is less than 0.5 times, the loss of charge from the photosensitive layer required for the undercoat layer is reduced, and charge stays in the photosensitive layer, which may cause image defects. Further, if it exceeds 2.0 times, the content volume of the metal oxide particles in the undercoat layer is large, and sufficient adhesiveness is obtained even when the thermoplastic resin particles are within the range of the particle size dispersion coefficient described in the present invention. Hard to get.

  The particle size dispersion coefficient ε is defined as ε = (D90−D10) / D50, and D10, D50, and D90 correspond to 10%, 50%, and 90% volume of the thermoplastic resin particles in the aqueous dispersion subbing layer coating liquid, respectively. It is defined as the particle size. The particle size dispersion coefficient ε of the thermoplastic resin particles in the undercoat layer is preferably in the range of 0.2 to 1.0. In particular, the range of 0.3 to 0.5 is more preferable.

  When the particle size dispersion coefficient ε is less than 0.2, the volume particle size distribution of the thermoplastic resin particles is extremely sharp and the particle size is almost constant. In this case, in the step of applying the water-dispersible undercoat layer coating solution on the support and forming the undercoat layer by the drying step, the gaps generated between the thermoplastic resin particles are reduced, and the metal oxide particles are thermoplastic resin. It is arranged at a position that separates the particles. For this reason, when the thermoplastic resin particles are melted in the drying step, the thermoplastic resin particles may not be sufficiently mixed with each other and adhesiveness may not be sufficiently obtained.

  When the particle size dispersion coefficient ε exceeds 1.0, the volume particle size distribution of the thermoplastic resin particles is extremely broad and the variation in the particle size increases. In this case, in the step of applying the aqueous dispersion subbing layer coating liquid on the support and forming the subbing layer by the drying step, the gap generated between the thermoplastic resin particles becomes large, and the metal oxide particles are concentrated in the gap. To do. For this reason, when the thermoplastic resin particles are dissolved in the drying process, the metal oxide particles are biased in the undercoat layer, and the charge removal from the photosensitive layer required for the undercoat layer is poor and the charge stays in the photosensitive layer. May occur, and image damage may occur.

  The primary particle diameter of the metal oxide particles is preferably 0.5 times or less of D50 of the thermoplastic resin particles. When the primary particle diameter of the metal oxide particles is within this range, the effects described in the present invention are particularly easily obtained. Outside this range, the distribution in the undercoat layer of the metal oxide has a small correlation with the particle size of the thermoplastic resin particles, and there is a possibility that adhesiveness cannot be obtained. The lower limit of the primary particle size of the metal oxide particles is not particularly provided, and the effect of the present invention can be obtained up to 1 nm.

In the method for producing an electrophotographic photoreceptor according to the present invention, D50, which is 50% volume of thermoplastic resin particles, is preferably 50 to 500 nm. This range is preferable for expressing the effects of the present invention. More preferably, it is 200-400 nm. When D50 is 50 nm or less, the effect of the present invention may not be sufficiently exhibited. When D50 is 500 nm or more, one particle becomes large and the binding between the thermoplastic resin particles becomes weak, and there is a possibility that sufficient adhesion cannot be obtained.
In the method for producing an electrophotographic photoreceptor according to the present invention, it is preferable that the thermoplastic resin particles contained in the aqueous dispersion subbing layer coating solution be a polyolefin resin. Polyolefin resins are suitable for the undercoat layer of an electrophotographic photosensitive member because they have good electrophotographic characteristics, environmental fluctuations, and film formability.

In the method for producing an electrophotographic photoreceptor according to the present invention, the heating temperature of the coating film is preferably equal to or higher than the melting point of the thermoplastic resin particles contained in the aqueous dispersion subbing layer coating solution. Good film characteristics can be obtained by heating and drying at a temperature equal to or higher than the melting point of the thermoplastic resin particles.
Specific examples of the polyolefin resin used in the present invention are preferably ethylene-methyl acrylate-maleic anhydride copolymer or ethylene-ethyl acrylate-maleic anhydride copolymer.
In addition, unsaturated carboxylic anhydride units such as maleic anhydride units form an acid anhydride structure in which adjacent carboxyl groups are dehydrated and cyclized in the dry state of the resin. However, particularly in an aqueous medium containing a basic compound, a part or all of the ring is opened to easily form a structure of a carboxylic acid or a salt thereof.

The polyolefin resin used in the present invention may be obtained by synthesis or a commercially available resin may be used.
The method for synthesizing the polyolefin resin is not particularly limited, but it is generally obtained by high-pressure radical copolymerization of the monomer constituting the polyolefin resin in the presence of a radical generator. The synthesis method of polyolefin resin is described in Chapter 4 (Kyoritsu Shuppan Co., Ltd.) of "New Polymer Experiment 2 Polymer Synthesis and Reaction (1)", JP-A 2003-105145, JP-A 2003-147028, and the like. Synthesized by known methods.
Examples of commercially available products include “Bondyne (registered trademark)” manufactured by Sumitomo Chemical Co., Ltd. and “Primacol (registered trademark)” manufactured by Dow Chemical.
The metal oxide particles used in the present invention are aluminum oxide, titanium oxide, zinc oxide, cerium oxide, yttrium oxide, silicon oxide, zirconium oxide, iron oxide, tin oxide, magnesium oxide, copper oxide, manganese oxide, antimony- Examples thereof include tin oxide, indium oxide-tin oxide, aluminum oxide tin oxide, and a mixture or composite oxide of two or more of these oxides.
The metal oxide particles can be surface treated using a surface treating agent as necessary.

Next, a method for producing the aqueous dispersion undercoat layer coating solution of the present invention will be described. The method for producing the aqueous dispersion subbing layer coating liquid containing thermoplastic resin particles and metal oxide particles is not particularly limited, but from the viewpoint of dispersibility of the metal oxide particles, the thermoplastic resin particle dispersion and the metal oxide are used. A method of preparing the particle dispersion separately and mixing them is preferred. Hereinafter, this method will be described in detail.
As a method for preparing the thermoplastic resin particle dispersion, for example, a method of heating and stirring in a container that can be sealed with polyolefin resin, water, and if necessary, an organic solvent can be employed. At this time, the shape of the polyolefin resin is not particularly limited, but it is preferable to use a granular or powdery particle having a particle diameter of 1 cm or less, preferably 0.8 cm or less, from the viewpoint of increasing the particle formation rate.

Any container may be used as long as it is equipped with a tank into which liquid can be charged and can appropriately stir the mixture of the resin and the aqueous solvent charged into the tank. As such an apparatus, an apparatus widely known to those skilled in the art as a solid / liquid stirring apparatus or an emulsifier can be used, and an apparatus capable of pressurization of 0.1 MPa or more is preferably used. The stirring method and the rotation speed of stirring are not particularly limited.
After each raw material is put into the tank of this apparatus, it is preferably stirred and mixed at a temperature of 40 ° C. or lower. Next, an aqueous dispersion can be obtained by continuing stirring for 5 to 120 minutes while maintaining the temperature in the tank at 50 to 200 ° C, preferably 60 to 200 ° C.

At this time, it is preferable to add a basic compound in order to anionize the unsaturated carboxylic acid unit of the polyolefin resin. The addition amount of the basic compound is preferably 0.5 to 3.0 times equivalent to the carboxyl group in the polyolefin resin (1 mol of acid anhydride group is regarded as 2 mol of carboxyl group), 0.8 -2.5 times equivalent is more preferable and 1.0-2.0 times equivalent is especially preferable. If it is less than 0.5 times equivalent, the addition effect of a basic compound is not recognized, and if it exceeds 3.0 times equivalent, the drying time at the time of coating film formation may become long, or an aqueous dispersion may color.
As a basic compound added here, the compound which volatilizes at the time of coating film formation is preferable, and ammonia or various organic amine compounds are preferable. Specific examples of the organic amine compound include triethylamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, and 3-ethoxypropylamine. , 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N- Mention may be made of ethylmorpholine.

The polyolefin resin particle dispersion obtained as described above is a uniform liquid in which the polyolefin resin is dispersed in an aqueous medium. “Uniform liquid” means that, in terms of appearance, a portion where the solid content concentration is locally different from other portions such as precipitation, phase separation or skinning is not found in the aqueous dispersion.
As a method for preparing the metal oxide particle dispersion, for example, a commercially available metal oxide is wet pulverized by a ball mill, a vibration ball mill, a roll mill, a triter, a sand mill and a colloid mill to obtain a dispersion. Alternatively, a slurry, a sol solution or the like dispersed in a commercially available aqueous solvent can be used as it is. Also, a method of hydrolyzing or thermally hydrolyzing metal oxides, a method of alkaline hydrolysis of an acidic solution containing metal ions, or a method of ion exchange of a solution containing metal ions with an ion exchange membrane or ion exchange resin is used. Can do.

When mixing the thermoplastic resin particle dispersion and the metal oxide particle dispersion obtained by separate operations in this way, the metal oxide particle dispersion is added to the thermoplastic resin particle dispersion and mixed. Also good. Conversely, the thermoplastic resin particle dispersion may be added to and mixed with the metal oxide particle dispersion.
The solvent used in the present invention may contain a hydrophilic organic solvent in addition to water. When preparing the thermoplastic resin particle dispersion, when preparing the metal oxide particle dispersion, it is preferable to adjust appropriately when mixing the thermoplastic resin particle dispersion and the metal oxide particle dispersion. Examples of the organic solvent include methyl ethyl ketone, acetone, diethyl ketone, propanol, butanol, methanol, ethanol, tetrahydrofuran, dioxane, and ethylene glycol monobutyl ether. The amount of these organic solvents in the total amount of the aqueous dispersion is preferably 40% by mass or less, more preferably 20% by mass or less, and further preferably 5% by mass or less.

In the present invention, the aqueous dispersion subbing layer coating solution obtained as described above is applied on a conductive support or a conductive layer, heated and dissolved to form a subbing layer. Is a method for producing an electrophotographic photosensitive member.
As a means for applying the aqueous dispersion subbing layer coating solution, a method used in this field is usually applicable, but dip coating is particularly preferable.
In the method for producing a photoreceptor of the present invention, when the aqueous dispersion subbing layer coating solution is applied by dip coating, the relative humidity at a temperature of 23 ° C. is 60% or less and the wind speed is 1 m / s or less. It is preferable to carry out with a dip coating apparatus installed in an environment.
The thickness of the undercoat layer is preferably in the range of 0.1 to 20 μm.

The support used for the electrophotographic photosensitive member may be a conductive one (conductive support), and examples thereof include a metal or an alloy such as aluminum, nickel, copper, gold and iron. Further, a thin film made of a metal such as aluminum, silver or gold, or a conductive material such as indium oxide or tin oxide may be formed on an insulating support such as polyester, polycarbonate, polyimide or glass. Moreover, the support body which disperse | distributed carbon and the electroconductive filler in resin, and provided electroconductivity may be sufficient.
The surface of the support may be subjected to electrochemical treatment such as anodization in order to improve electrical characteristics and adhesion. Further, the surface of the support may be chemically treated with a solution obtained by dissolving a metal salt compound or a fluorine compound metal salt in an acidic aqueous solution mainly composed of alkali phosphate or phosphoric acid or tannic acid. .

In addition, when the electrophotographic photosensitive member of the present invention is used in an electrophotographic apparatus that uses single-wavelength light such as laser light as exposure light (image exposure light), the surface of the support is appropriately adjusted to suppress interference fringes. It is preferable to roughen the surface. Specifically, the surface of the support is subjected to treatment such as honing, blasting, cutting, and electropolishing, or a conductive film containing a conductive metal oxide and a binder resin is provided on the support. preferable.
The honing process includes a dry process and a wet process, either of which may be adopted. The wet honing treatment is a method in which a suspension obtained by suspending a powdery abrasive in a liquid such as water is sprayed on the surface of a support at a high speed to roughen the surface. In the case of the wet honing treatment, the surface roughness of the support can be controlled by the spraying pressure of the suspension, the speed, the amount of the abrasive, the type, shape, size, hardness, specific gravity and suspension temperature. The dry honing treatment is a method in which an abrasive is sprayed onto the surface of a support with air at a high speed to roughen the surface. Also in the case of the dry honing treatment, the surface roughness of the support can be controlled in the same manner as the wet honing treatment. Examples of the abrasive used for the honing treatment include particles such as silicon carbide, alumina, iron, and glass beads.

A conductive layer may be provided between the support and the undercoat layer of the present invention for the purpose of suppressing interference fringes due to laser light scattering and covering the support.
The conductive layer can be formed by dispersing conductive particles such as carbon black, metal particles, and metal oxide particles in a binder resin. Examples of the metal oxide particles include zinc oxide and titanium oxide particles. Further, barium sulfate particles coated with oxygen-deficient SnO ₂ can also be used as the conductive particles.
Examples of the binder resin used for the conductive layer include a phenol resin, a polyurethane resin, and a polyamide resin. These have good adhesion to the support, improve the dispersibility of the conductive particles, and have good solvent resistance after film formation.
Further, a leveling agent may be added to the conductive layer in order to improve the surface property of the conductive layer.

A further layer having a function such as an adhesive function may be provided between the undercoat layer and the photosensitive layer of the present invention. Examples include casein, polyvinyl alcohol, nitrocellulose, polyamide (such as nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethylated nylon), polyurethane and aluminum oxide.
The charge generation layer can be formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent and drying the coating solution.

As the charge generation material used in the present invention,
(1) Azo pigments such as monoazo, disazo, trisazo,
(2) phthalocyanine pigments such as metal phthalocyanines and nonmetal phthalocyanines;
(3) Indigo pigments such as indigo and thioindigo,
(4) Perylene pigments such as perylene anhydride and perylene imide,
(5) polycyclic quinone pigments such as anthraquinone and pyrenequinone,
(6) squarylium dye,
(7) pyrylium salt, thiapyrylium salt,
(8) triphenylmethane dye,
(9) Inorganic materials such as amorphous silicon,
(10) quinacridone pigment,
(11) an azulenium salt pigment,
(12) cyanine dyes,
(13) a xanthene dye,
(14) quinoneimine dye,
(15) styryl dye,
(16) cadmium sulfide,
(17) Examples include zinc oxide. Among these, metal phthalocyanine pigments are particularly preferable. Among these, oxytitanium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, and hydroxygallium phthalocyanine are preferable. Of these, hydroxygallium phthalocyanine is particularly preferred.

As oxytitanium phthalocyanine,
An oxytitanium phthalocyanine crystal having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction; and
Bragg angles (2θ ± 0.2 °) of 9.5 °, 9.7 °, 11.7 °, 15.0 °, 23.5 °, 24.1 ° and 27.3 in CuKα characteristic X-ray diffraction Oxytitanium phthalocyanine crystals having a strong peak at ° are preferred.

As chlorogallium phthalocyanine,
Chlorogallium phthalocyanine crystals having strong peaks at 7.4 °, 16.6 °, 25.5 and 28.2 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction,
Chlorogallium phthalocyanine crystals having strong peaks at 6.8 °, 17.3 °, 23.6 ° and 26.9 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction, and
Strong peaks at Bragg angles (2θ ± 0.2 °) of 8.7 ° to 9.2 °, 17.6 °, 24.0 °, 27.4 ° and 28.8 ° in CuKα characteristic X-ray diffraction A chlorogallium phthalocyanine crystal is preferable.

As dichlorotin phthalocyanine,
Strong peaks at 8.3 °, 12.2 °, 13.7 °, 15.9 °, 18.9 ° and 28.2 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction Having dichlorotin phthalocyanine crystals,
Dichlorotin phthalocyanine crystals having strong peaks at 8.5 °, 11.2 °, 14.5 ° and 27.2 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction;
Bragg angles (2θ ± 0.2 °) of 8.7 °, 9.9 °, 10.9 °, 13.1 °, 15.2 °, 16.3 °, 17.4 in CuKα characteristic X-ray diffraction Dichlorotin phthalocyanine crystals with strong peaks at °, 21.9 ° and 25.5 °, and
Strong peaks at 9.2 °, 12.2 °, 13.4 °, 14.6 °, 17.0 ° and 25.3 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction The dichlorotin phthalocyanine crystal | crystallization which has is preferable.

As hydroxygallium phthalocyanine,
Hydroxygallium phthalocyanine crystals having strong peaks at 7.3 °, 24.9 ° and 28.1 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction; and
Strong peaks at Bragg angles (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° Hydroxygallium phthalocyanine crystals are preferred.

Examples of the binder resin for the charge generation layer include butyral resin, polyester resin, polycarbonate resin, polyarylate resin, polystyrene resin, polyvinyl methacrylate resin, polyvinyl acrylate resin, polyvinyl acetate resin, polyvinyl chloride resin, polyamide resin, polyurethane Examples thereof include resins, silicone resins, alkyd resins, epoxy resins, cellulose resins, and melamine resins. Among these, a butyral resin is preferable.
The dispersed particle diameter of the charge generation material in the charge generation layer is preferably 0.5 μm or less, more preferably 0.3 μm or less, and more preferably 0.01 μm or more and 0.2 μm or less.
The film thickness of the charge generation layer is preferably from 0.01 μm to 2 μm, more preferably from 0.05 μm to 0.3 μm.

The charge transport layer is formed of a suitable charge transport material, for example, a heterocyclic compound such as poly-N-vinylcarbazole or polystyrylanthracene or a polymer compound having a condensed polycyclic aromatic compound, or a complex such as pyrazoline, imidazole, oxazole, triazole or carbazole. Low molecular weight compounds such as ring compounds, triarylalkane derivatives such as triphenylmethane, triarylamine derivatives such as triphenylamine, phenylenediamine derivatives, N-phenylcarbazole derivatives, stilbene derivatives, and hydrazone derivatives are appropriately bound to resins ( A solution dispersed / dissolved in a solvent together with the resin for charge generation layer) can be applied by the above-mentioned known method and dried. In this case, the ratio of the charge transport material to the binder resin is such that the mass of the charge transport material is preferably 20 to 100, more preferably 30 to 100 when the total mass of both is 100. If the amount of the charge transport material is smaller than that, the charge transport ability is lowered, and problems such as a decrease in sensitivity and an increase in residual potential occur. In this case, the thickness of the charge transport layer is preferably adjusted in the range of 1 to 50 μm, more preferably 3 to 30 μm.
Furthermore, a surface protective layer may be formed on the charge transport layer.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Hereinafter, “part” indicates “part by mass”, and “%” indicates “% by mass”.
The particle size and particle size dispersion coefficient ε of the thermoplastic resin particles and the particle size of the metal oxide particles were obtained from Malvern Instrument Ltd. Zetasizer NanoZS light scattering particle size distribution meter (MODEL ZEN 3600). The measurement solvent was the same as the solvent composition of the aqueous dispersion subbing layer coating solution, and the volume particle size distribution at a measurement temperature of 25 ° C. was determined.

[Example 1]
An aluminum base tube (ED tube) of A3003 obtained by hot extrusion and having an outer diameter of 30.5 mm, an inner diameter of 28.5 mm, and a length of 260.5 mm was prepared.
Next, 120 parts of powder composed of fine particles of barium sulfate having a coating layer formed of tin oxide (coverage: 50 mass%, powder specific resistance: 700 Ω · cm)
70 parts of resol type phenolic resin (Brand Orphen J-325, manufactured by Dainippon Ink & Chemicals, solid content 70%)
2-Methoxy-1-propanol 100 parts The above material solution was dispersed in a ball mill for about 20 hours to prepare a coating solution for conductive particle resin dispersion layer (the average particle size of the filler contained in this coating solution is 0.22 μm). Met). This liquid is applied onto the aluminum base tube by a dip coating method, and is heated and cured at a temperature of 140 ° C. for 30 minutes to form a conductive particle resin dispersion layer having a thickness of 15 μm. It was.

Next, an aqueous dispersion subbing layer coating solution was prepared as follows. Using a stirrer equipped with a glass container for a pressure-resistant 1 liter that can be sealed with a heater,
Thermoplastic resin A 75.0g
(The thermoplastic resin A is a polyolefin copolymer composed of 3 parts maleic anhydride, 79 parts ethylene, and 18 parts ethyl acrylate).
2-Propanol (IPA) 60.0g
Triethylamine (TEA) 5.1g
And 159.9 g of distilled water were charged into a glass container and stirred at a rotating speed of the stirring blade of 300 rpm. It was confirmed that no sedimentation of resin particles was observed at the bottom of the container, and that it was in a floating state. It was. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. The system temperature was kept at 140 ° C. to 145 ° C. and further stirred for 20 minutes. Then, after putting in a water bath and cooling to room temperature (about 25 ° C.) while stirring at a rotational speed of 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) did. And the aqueous dispersion A containing milky white uniform polyolefin resin particle was obtained.

  Dissolve 0.2 mol of stannic chloride pentahydrate in 200 ml of water to make a 0.5M aqueous solution, and add white tin oxide ultrafine particles with pH 1.5 by adding 28% ammonia water while stirring A slurry was obtained. The obtained tin oxide ultrafine particle-containing slurry is heated to a temperature of 70 ° C. and then naturally cooled to a temperature of about 50 ° C., and then pure water is added to obtain a 1 L tin oxide ultrafine particle-containing slurry. Separation was performed. After adding 800 ml of pure water to this water-containing solid content, stirring and dispersing with a homogenizer, washing was performed by solid-liquid separation using a centrifuge. 75 ml of pure water was added to the water-containing solid content after washing to prepare a tin oxide ultrafine particle-containing slurry. To the obtained tin oxide ultrafine particle-containing slurry, 3.0 ml of triethylamine (boiling point: 89.7 ° C.) was added and stirred. Then, the tin oxide sol solution which used organic amine with a solid content concentration of 20 mass% as a dispersion stabilizer was obtained by stopping heating and naturally cooling.

99 parts of aqueous dispersion A, 875 parts of the above tin oxide sol solution, and 350 parts of IPA were mixed to prepare an aqueous dispersion undercoat layer coating solution. The resin particle size in the aqueous dispersion undercoat layer coating solution solvent composition was 0.240 μm, and the particle size dispersion coefficient ε was 0.37.
The aqueous dispersion undercoat layer coating solution obtained on the conductive support was applied by a dip coating method and dried at a temperature of 120 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.8 μm.

Hydroxygallium phthalocyanine (charge generating material) 20 parts (crystal form having strong peaks at 7.3 °, 24.9 ° and 28.1 ° of Bragg angles (2θ ± 0.2 °) in characteristic X-ray diffraction of CuKα) )
Polyvinyl butyral resin (trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.) 10 parts Cyclohexanone 350 parts The above materials are dispersed in a sand mill using glass beads having a diameter of 1 mm for 3 hours, and 1200 parts of ethyl acetate is added thereto. Diluted. At this time, the dispersed particle diameter of the charge generation material CAPA-700 (manufactured by Horiba, Ltd.) was 0.15 μm. On the undercoat layer, this charge generation layer coating solution was applied by dip coating and dried at a temperature of 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm. The thermoplastic resin particles in the aqueous dispersion coating solution for the undercoat layer were insoluble in the charge generation layer coating solution.

  Next, 7 parts of a compound represented by the following structural formula (1), 1 part of a compound represented by the following formula (2), and a bisphenol C-type polyarylate resin (Mw110000) having a structural unit represented by the following formula (3) 10 parts was dissolved in 50 parts of monochlorobenzene / 10 parts of methylal in a mixed solvent to prepare a coating for a charge transport layer. This paint was applied on the charge generation layer by a dip coating method and dried at a temperature of 110 ° C. for 1 hour to form a charge transport layer having a thickness of 18 μm. Thus, an electrophotographic photosensitive member was produced.

For the evaluation, an electrophotographic apparatus, a color laser printer manufactured by Hewlett-Packard Co., Ltd., and a modified laser jet 4600 (the contact line pressure of the cleaning blade with respect to the electrophotographic photosensitive member is set to 550 mN / cm) were used. The prepared electrophotographic photosensitive member was mounted, and the surface of the photosensitive member after 10000 sheets printing was observed. Evaluation was performed as follows.
・ No appearance abnormality ○
・ The photosensitive layer is lifted.
・ Photosensitive layer is peeled off ×
Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

[Example 2]
1000 parts of glass beads having a diameter of 1 mm were added to 100 parts of titanium oxide (PT401M, manufactured by Ishihara Sangyo Co., Ltd.), 750 parts of methanol, and 50 parts of distilled water, and dispersed for 15 hours with a paint shaker.
An undercoat layer and a photoreceptor were prepared and evaluated in the same manner as in Example 1 except that 900 parts of the titanium oxide dispersion liquid was used instead of the tin oxide sol solution of the aqueous dispersion undercoat layer coating liquid. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

Example 3
An undercoat layer and a photoconductor were prepared and evaluated in the same manner as in Example 2 except that titanium oxide (PT401M, manufactured by Ishihara Sangyo Co., Ltd.) was used instead of titanium oxide (TTO-51A, manufactured by Ishihara Sangyo Co., Ltd.). went. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

Example 4
An undercoat layer and a photoreceptor were prepared and evaluated in the same manner as in Example 1 except that the rotation speed of the stirring blade was 100 rpm and the heating temperature of the heater was kept at 120 ± 5 ° C. and stirring was continued for 20 minutes. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

Example 5
An undercoat layer and a photoreceptor were prepared and evaluated in the same manner as in Example 1 except that the rotation speed of the stirring blade was 500 rpm and the heating temperature of the heater was maintained at 150 ± 5 ° C. and stirring was continued for 1 hour. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

Example 6
An undercoat layer and a photoconductor were prepared in the same manner as in Example 3 except that the thermoplastic resin A was a polyolefin copolymer composed of 1 part maleic anhydride, 60 parts ethylene, and 39 parts ethyl acrylate in terms of mass ratio. And evaluated. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

Example 7
The thermoplastic resin A is made into a polyolefin copolymer composed of 3 parts of maleic anhydride, 87 parts of ethylene and 10 parts of ethyl acrylate by mass ratio, and is changed to titanium oxide (PT401M, manufactured by Ishihara Sangyo Co., Ltd.). An undercoat layer and a photoconductor were prepared and evaluated in the same manner as in Example 2 except that CR-EL (manufactured by Ishihara Sangyo Co., Ltd.) was used. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

Example 8
The thermoplastic resin A is made into a polyolefin copolymer composed of 3 parts of maleic anhydride, 90 parts of ethylene and 7 parts of ethyl acrylate by mass ratio, and is changed to titanium oxide (PT401M, manufactured by Ishihara Sangyo Co., Ltd.). An undercoat layer and a photoreceptor were prepared and evaluated in the same manner as in Example 2 except that PT-301 (manufactured by Ishihara Sangyo Co., Ltd.) was used. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

[Comparative Example 1]
An undercoat layer and a photoreceptor were prepared and evaluated in the same manner as in Example 2 except that the rotation speed of the stirring blade was 50 rpm and the heating temperature of the heater was maintained at 110 ± 5 ° C. and stirring was continued for 20 minutes. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

[Comparative Example 2]
An undercoat layer and a photoreceptor were prepared and evaluated in the same manner as in Example 2 except that the rotation speed of the stirring blade was 1000 rpm and the heating temperature of the heater was maintained at 170 ± 5 ° C. and stirring was further performed for 2 hours. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

[Comparative Example 3]
An undercoat layer and a photoconductor were prepared and evaluated in the same manner as in Example 2 except that titanium oxide (TTO51A, manufactured by Ishihara Sangyo Co., Ltd.) was used instead of titanium oxide (PT-301, manufactured by Ishihara Sangyo Co., Ltd.). went. Table 1 shows the particle diameter, the measurement result of the particle size dispersion coefficient, and the evaluation result.

以上のように、本発明により、支持体と感光層の接着性が良好な電子写真感光体の製造方法を見出した。

As described above, the present invention has found a method for producing an electrophotographic photoreceptor having good adhesion between the support and the photosensitive layer.

Claims (4)

The substrate has a subbing layer and a photosensitive layer, and the aqueous dispersion subbing layer coating liquid applied to form the subbing layer contains thermoplastic resin particles and metal oxide particles that are insoluble in water. The volume ratio of the metal oxide particles to the thermoplastic resin particles is 0.5 to 2.0 times,
The particle size distribution of the thermoplastic resin particles in the aqueous dispersion subbing layer coating solution corresponding to 10%, 50%, and 90% volume is D10, D50, and D90, respectively, and the particle size dispersion coefficient ε = ( D90−D10) / D50, the particle size dispersion coefficient ε satisfies 0.2 or more and 1.0 or less, and the primary particle size of the metal oxide particles is 0.5 times or less of the D50. A method for producing an electrophotographic photoreceptor, comprising: forming an undercoat layer by applying an undercoat layer coating solution to form a coating film, and then heating the coating film to melt the thermoplastic resin particles.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the D50 is 50 to 500 nm.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the thermoplastic resin particles are a polyolefin resin. The method for producing an electrophotographic photosensitive member according to any one of claims 1 to 3, wherein a heating temperature of the coating film is equal to or higher than a melting point of the thermoplastic resin particles.