JP5268474B2 - Method for preparing coating solution for electrophotographic photosensitive member and method for producing electrophotographic photosensitive member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an application liquid having excellent dispersion stability and coating properties for organic pigment. <P>SOLUTION: The method for producing an application liquid for electrophotographic photoreceptor which is obtained by dispersing an organic pigment and a polyamide resin to a solvent includes processes of preparing a gelled polyamide resin by use of an alcohol and the polyamide resin; dispersing the gelled polyamide to the solvent to prepare a polyamide resin dispersion liquid with a volume average particle size (D<SB>50</SB>) of 0.50 &mu;m or more and 6.00 &mu;m or less as a measurement value by dynamic light scattering method; adding and dispersing the organic pigment to the polyamide dispersion liquid; and adding a diluting solvent to the polyamide resin dispersion liquid with the organic pigment dispersed therein to prepare the application liquid for electrophotographic photoreceptor. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a process for the production of electronic photoreceptor coating solution preparation and electrophotographic photosensitive member.

  Organic pigments such as azo pigments typified by monoazo pigments and disazo pigments and polycyclic pigments typified by phthalocyanine pigments generally have a lower specific gravity than inorganic pigments such as titanium oxide. High liquid stability due to low sedimentation due to its small specific gravity, various absorption wavelengths due to modification to unique molecular structure, and high purity and stable quality because it can be synthesized by chemical reaction industrially It is possible to maintain the above. Therefore, various printing inks and photosensitive characteristics are applied as pigments and used in optical disks, solar cells, electrophotographic materials and the like.

  Polyamide resins have good mechanical properties and chemical resistance, and are used in a wide range of fields as electronic parts, automobile parts, fibers, and films as engineering plastics. Among them, there are alcohol-soluble polyamide resins such as N-alkoxyalkylated nylon and copolymer nylon, which are polyamide resins modified so as to increase solubility in alcohol. Alcohol-soluble polyamide resins have characteristics such as transparency, flexibility, and adhesiveness, and are used for surface treatment of clothing, adhesives for electronic materials, water-based inks, electrophotographic materials, and the like.

  The coating surface of the dispersion liquid in which the organic pigments such as azo pigments and polycyclic pigments described above are dispersed in a small particle size in the alcohol-based liquid of the alcohol-soluble polyamide resin has no unevenness of application and gives a glossy feeling. It is done. However, it is possible to obtain organic pigments such as azo pigments and polycyclic pigments as described above as a stable dispersion with a small particle size for a long time in the alcohol-based liquid of alcohol-soluble polyamide resin. May occur and is very difficult.

  In addition, the electrophotographic photosensitive member using the organic electrophotographic material as described herein is pollution-free and easy to manufacture as compared with conventional electrophotographic photosensitive members using inorganic electrophotographic materials such as Se and CdS. There is an advantage that the degree of freedom in functional design is high due to the variety of selection of materials. An electrophotographic photosensitive member using such an organic electrophotographic material has been widely used in the market due to the rapid spread of laser beam printers and copying machines in recent years. In recent years, as the image quality and color of printers and copiers have been improved, the requirements for the quality of electrophotographic photoreceptors have increased, and electrophotographic photoreceptors free from image defects are desired.

  An electrophotographic photoreceptor basically comprises a photosensitive layer that forms a latent image by exposure using charging and light, and a support as a support member for providing the photosensitive layer. To date, an undercoat layer has been provided between the support and the photosensitive layer in order to ensure adhesion to the support, protect the photosensitive layer from electrical breakdown, improve the carrier injection property of the photosensitive layer, and the like. I came. In order to further improve the properties of the undercoat layer, various methods for dispersing the organic pigment in the undercoat layer have been proposed.

  For example, Patent Document 1 discloses a technique for reducing the residual potential of the photoreceptor by using an undercoat layer.

Patent Document 2 suppresses the increase in residual potential during repeated use, Patent Document 3 suppresses charging stability from the first print rotation process, and Patent Documents 4 to 6 suppress potential fluctuations and ghosts during continuous printing. Technology to do is presented.
Japanese Patent No. 3384231 Japanese Patent Publication No.7-111586 Japanese Patent No. 3417145 Japanese Patent No. 3774673 JP 2003-316049 A International Publication No. 2005/116777 Pamphlet

  However, these proposals use a pigment dispersion as a coating solution for an electrophotographic photoreceptor. For this reason, the film thickness of the electrophotographic photosensitive member becomes non-uniform due to local solid content fluctuations of the dispersion due to sedimentation of the pigment particles and increase in the particle size due to aggregation of the pigment particles, and the concentration on the coated surface of the electrophotographic photosensitive member. There is a potential problem that unevenness and image defects increase. Such density unevenness and image defects can be fatal defects of the electrophotographic photosensitive member in improving the image quality of the above-described printer and copying machine. Also, there is a problem that the coating life of the electrophotographic photosensitive member coating solution is shortened due to the sedimentation or aggregation of the pigment particles, and in order to solve these problems, the pigment particles contained in the electrophotographic photosensitive member coating solution are further updated. There is a need for improved miniaturization and stability.

The present invention has been made in view of the above problems of the background art. The average particle diameter (median diameter) of the organic pigment measured by the centrifugal sedimentation method is extremely small, and the specific surface area of the organic pigment is particularly large. It is an object of the present invention to provide a method for preparing a coating solution for an electrophotographic photoreceptor, and a method for producing an electrophotographic photoreceptor in which a coating solution is prepared by the preparation method and an undercoat layer is formed using the prepared coating solution. To do.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have paid attention to a polyamide resin used for preparing a coating solution for an electrophotographic photoreceptor obtained by dispersing an organic pigment and a polyamide resin. In the preparation of the electrophotographic photoreceptor coating solution, a polyamide resin gelled as a polyamide resin is used for dispersion with an organic pigment, and after the gelled polyamide resin is dispersed in a solvent, the organic pigment is In addition, disperse. As a result, the shape of the gel used for dispersion affects the particle size distribution of the organic pigment in the dispersion, and the viscosity of the dispersion rapidly rises due to the organic pigment entering, so it is inserted from outside the fixed container. In a sand mill having a rotary stirring unit attached to the rotary shaft in the fixed container, particularly a batch type sand mill, it is possible to prevent the gel and the organic pigment from being mixed with each other.

  As a result, a highly stable coating solution for electrophotographic photoreceptors having an extremely small average particle diameter (median diameter) of the organic pigment in the coating solution for electrophotographic photoreceptors measured by centrifugal sedimentation and a particularly large specific surface area. As a result, the present invention was completed.

That is, the present invention is,

Preparing a polyamide resin obtained by gelation using the A alcohol and polyamide resin,
Step polyamide resin obtained by the gel is dispersed in a solvent, to the volume average particle size (D _50), prepare 6.00μm or less of the polyamide resin dispersions or 0.50μm in the measured value by the dynamic light scattering method When,
Adding and dispersing an organic pigment in the polyamide resin dispersion;
In the polyamide resin dispersion obtained by dispersing the organic pigment, the steps of, prepare an electrophotographic photoreceptor coating solution by adding a diluting solvent,
Is a process for the preparation of an electrophotographic photoreceptor coating solution have a.
The present invention also provides:
In the method for producing an electrophotographic photoreceptor by laminating an undercoat layer and a photosensitive layer on a conductive support, a coating solution is prepared by the above preparation method, and the undercoat layer is formed using the prepared coating solution. A method for producing an electrophotographic photosensitive member.

The method for preparing a coating solution for an electrophotographic photosensitive member according to the present invention is characterized in that a polyamide resin gelled in alcohol is dispersed in advance, and then an organic pigment is added and dispersed. This is a preparation method. As a result, the coating liquid for an electrophotographic photosensitive member has a very small average particle diameter (median diameter) of the organic pigment in the coating liquid for an electrophotographic photosensitive member measured by a centrifugal sedimentation method, a particularly large specific surface area, and high stability. There is an effect that can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail.

Process for the preparation of an electrophotographic photoreceptor coating solution of the present invention, after the pre-dispersed polyamide resin gelled in alcohol, is the preparation method of dispersing by adding an organic pigment.

The method for preparing a coating solution for an electrophotographic photoreceptor of the present invention includes the following steps.

First, a step of preparing a gelled polyamide resin using an alcohol and a polyamide resin is included. Next, the gelled polyamide resin is dispersed in a solvent in the absence of the organic pigment, and the volume average particle diameter (D ₅₀ ) measured by the dynamic light scattering method is 0.50 μm or more and 6.00 μm. The process of making the following polyamide resin dispersion liquid is included. Furthermore, a step of dispersing the organic pigment in the polyamide resin dispersion is included.

  The gelled polyamide resin described here means a polyamide resin sample that can be determined to be in a solid state by performing a solid-liquid determination test in accordance with ASTM D 4359-90.

  The non-gelled polyamide resin means a polyamide resin sample that can be determined to be in a liquid state by performing a solid-liquid determination test in accordance with ASTM D 4359-90.

  Further, the high stability was judged by putting the electrophotographic photosensitive member coating solution in a stoppered graduated cylinder (capacity 10 ml) in an amount such that the liquid level was 50 mm and allowing it to stand for a certain period. Specifically, the organic pigment was separated after standing for 1 month in a 23 ° C. environment and 35 ° C. environment in which 1.5 wt% of water was added to the electrophotographic photosensitive member coating solution, and after standing for 3 months. If the organic pigment is not separated or the separation of the organic pigment is 1 mm or less, the stability is judged high.

  The gelled polyamide resin can be prepared by combining the following conditions after heating and dissolving the polyamide resin in alcohol.

  First, the kind of polyamide resin is not particularly limited as long as a desired gelled polyamide resin can be prepared. The types of polyamide resin are nylon 6, nylon 11, nylon 12, nylon 66, and nylon 610. Further, N-alkoxyalkylated nylon represented by N-methoxymethylated 6 nylon and N-methoxymethylated 12 nylon and nylon copolymer represented by quaternary nylon copolymer of nylon 6-66-610-12 Conventionally known materials such as coalescence can be used.

  The type of the polyamide resin is determined in consideration of the solubility in the alcohol that causes the polyamide resin to gel and the ease of gelation of the polyamide resin. One type or two or more types of polyamide resins can be used in combination.

  The polyamide resin to be used preferably contains at least N-alkoxyalkylated nylon, and more preferably contains at least N-alkoxyalkylated nylon having an N-alkoxyalkylation rate of 20% to 45%. Moreover, it is particularly preferable that N-methoxymethylated nylon having at least an N-methoxymethylation rate of 20% to 45% is included. In addition, N-methoxymethylation rate was measured by the method shown below by NMR.

  N-alkoxyalkylated nylon, which is a type of polyamide resin, has a repetitive unit of the nylon main chain as compared with copolymer nylon in which a plurality of types of nylon are chemically bonded to the main chain. Therefore, it is excellent in crystallinity and it is easy to prepare a gelled polyamide resin. Further, when the N-alkoxyalkylated nylon has an N-alkoxyalkylation rate lower than 20%, the solubility in a solvent is lowered, and it may be difficult to prepare a gelled polyamide resin. On the other hand, when the N-alkoxyalkylation rate is higher than 45%, the solubility in a solvent increases, and the stability of the gelled polyamide resin may deteriorate.

  The method for measuring the N-methoxymethylation rate is described below.

<Measurement method of N-alkoxyalkylation rate>
apparatus:
Measuring apparatus: FT NMR apparatus JNM-EX400 (manufactured by JEOL Ltd.)
Measurement frequency: 400MHz
Pulse condition: 5.0 μS
Data points: 32768
Frequency range: 10500Hz
Integration count: 32 times Measurement temperature: 25 ° C
sample:
N-methoxymethylated nylon 25mg
Methanol-D4 (99.8 atom% D) 0.75 ml made by Aldrich
Tetramethylsilane (internal standard) 0.05% by weight based on methanol-D4
Method of calculation:
A: Integral value of methylene proton (ca.2.4 ppm) adjacent to the carbonyl portion of the amide group which is N-methoxymethylated B: Methylene proton (ca) adjacent to the carbonyl portion of the amide group which is not N-methoxymethylated 2.2 ppm) N-methoxymethylation rate (%) = A / (A + B) × 100

  The alcohol used when the polyamide resin is gelled is not particularly limited as long as the desired gelled polyamide resin can be prepared, but is preferably a straight chain having 1 to 6 carbon atoms. Or it is alcohol with a branched chain. More preferred are methanol, ethanol, isopropanol, n-propanol, n-butanol, 2-butanol and isobutanol. Particularly preferred is ethanol or n-butanol. In addition, the alcohol may be combined with one or more alcohols in consideration of the solubility of the polyamide resin and the ease of preparation of the gelled polyamide resin.

  The temperature at which the polyamide resin is gelled is not particularly limited as long as a desired gelled polyamide resin can be obtained. In order to obtain a stably gelled polyamide resin, it is desirable to cool the polyamide resin heated and dissolved in a solvent, and it is more desirable to cool to 30 ° C. or lower.

  The solid content of the gelled polyamide resin is not particularly limited as long as a desired gelled polyamide resin can be prepared. Considering the stability of the gelled polyamide resin, the solid content of the polyamide resin is preferably 2% or more by mass%, more preferably 5% or more, and most preferably 5.0% or more and 30.30. The range is 0% or less. If the solid content of the polyamide resin is too low, a gelled polyamide resin may not be prepared.

  The shape of the gelled polyamide resin is not particularly limited as long as a desired coating solution for an electrophotographic photoreceptor can be prepared. Considering workability in the dispersion operation, it is preferable to crush the gelled polyamide resin to a size of 0.5 mm to 10 mm before dispersion. When the gelled polyamide resin is smaller than 0.5 mm, the crushed gelled polyamide resins are likely to adhere to each other, and workability may be deteriorated. If the gelled polyamide resin is larger than 10 mm, an undispersed portion of the gelled polyamide resin may remain after the dispersion is completed. A ball mill, an ultrasonic disperser, a high-pressure homogenizer, a stirrer, a mixer, a stirrer, a roll mill, an emulsifying disperser, a mesh, a sieve, a mincer, or the like is used for crushing the gelled polyamide resin.

An electrophotographic photoreceptor coating solution, after the polyamide resin is gelled by predispersed, prepare polyamide resin dispersion, prepared by dispersing by adding an organic pigment and a solvent to the polyamide resin dispersion. When the gelled polyamide resin is dispersed, it is preferable to determine the dispersion share so that the gelled polyamide resin used for dispersion is efficiently dispersed. If the dispersion share is too low, the gelled polyamide resin will not be dispersed, and if the dispersion share is too high, the liquid temperature during dispersion will rise, and the volume average of the polyamide resin dispersion measured by the dynamic light scattering method will be The particle size (D ₅₀ ) may be less than 0.50 μm.

  As a dispersion method, a known method, for example, a method using a dispersion device such as a paint shaker, a ball mill, a sand mill, an ultrasonic disperser, a high-pressure homogenizer, a stirrer, a mixer, a stirrer, a roll mill, or an emulsifying disperser is used. Can do. Here, the sand mill has a rotating stirring unit attached to a rotating shaft inserted from outside the fixed container in the fixed container. In particular, a batch sand mill can prevent the gel and the organic pigment from being mixed with each other.

  Considering the dispersibility of the electrophotographic photoreceptor coating liquid, after the gelled polyamide resin and the organic pigment are dispersed in the solvent, a dilution solvent is added to the fluidity of the electrophotographic photoreceptor coating liquid. Is preferable.

  As a solvent for dilution, it is preferable to contain any of ethanol, isopropanol, n-propanol, n-butanol, 2-butanol, isobutanol, and propylene glycol monomethyl ether.

  As the organic pigment, conventionally known pigments such as azo pigments such as monoazo, bisazo, trisazo, and tetrakisazo, phthalocyanine pigments such as gallium phthalocyanine and titanyl phthalocyanine, and perylene pigments can be used. Of these, phthalocyanine pigments and azo pigments are preferred. Moreover, these organic pigments can be used alone or in combination of two or more.

Examples of the phthalocyanine pigment described above include crystalline hydroxygallium having strong peaks at positions of Bragg angles 2θ = 7.4 ° ± 0.3 ° and 2θ = 28.2 ° ± 0.3 ° in CuKα characteristic X-ray diffraction. Phthalocyanine crystals are preferred.

The azo pigment is preferably a bisazo pigment represented by the following general formula (1).

  The mass ratio of the organic pigment and the polyamide resin contained in the coating solution for an electrophotographic photosensitive member is the stability of the coating solution for the electrophotographic photosensitive member and the output image of the electrophotographic photosensitive member using the coating solution for the electrophotographic photosensitive member. It is determined in consideration of density unevenness. Preferably, the mass ratio of the organic pigment and the polyamide resin contained in the coating solution for an electrophotographic photoreceptor is 1: 100 or more and 2: 1 or less. When the mass ratio of the organic pigment and the polyamide resin contained in the electrophotographic photosensitive member coating liquid is higher than 2: 1, the dispersibility of the pigment may deteriorate and the liquid stability of the electrophotographic photosensitive member coating liquid may deteriorate. is there. Further, when the mass ratio of the organic pigment and the polyamide resin contained in the coating solution for electrophotographic photoreceptor is lower than 1: 100, the output image of the electrophotographic photoreceptor using the coating solution for electrophotographic photoreceptor during continuous printing Density unevenness may worsen.

  The solid content of the coating solution for an electrophotographic photosensitive member is determined in consideration of the stability and coating properties of the coating solution for an electrophotographic photosensitive member, and is preferably 0.5% or more and 15% or less by mass%, and more preferably. Is 1% or more and 10% or less. If the solid content of the coating solution for electrophotographic photosensitive member is higher than 15%, the fluidity of the coating solution for electrophotographic photosensitive member is lost or the dispersibility is deteriorated and the liquid stability of the coating solution for electrophotographic photosensitive member is lowered. Sometimes. Also, if the solid content of the electrophotographic photosensitive member coating solution is lower than 0.5%, image density unevenness and image defects due to coating unevenness, film sag, etc. of the electrophotographic photosensitive member using the electrophotographic photosensitive member coating solution occur. Sometimes.

The volume average particle diameter (D ₅₀ ) of the polyamide resin dispersion was measured using “MICROTRAC PARTIPLE-SIZE ANALYZER 9340 UPA” (manufactured by Leeds & Northrup) based on the dynamic light scattering method as the measurement principle under the following conditions. .

<Microtrack UPA measurement conditions>
Calculation and control program version: 4.53E
Mode: FullRange
Transparent Particles: Yes
Physical Particles: No
Particle Refractive Index: 1.51
Particle Density: 1.20g / cc
Fluid: Ethanol
Fluid Refractive Index: 1.33
Fluid High Temp: 30.0 ° C. Viscosity 1.003 mPa · s
Fluid Low Temp: 20.0 ° C. Viscosity 1.200 mPa · s
Run Time: 180sec

  The average particle diameter (median diameter) and Sw (specific surface area) of the organic pigment in the electrophotographic photosensitive member coating solution were measured using a centrifugal sedimentation type particle size distribution analyzer CAPA-700 (manufactured by Horiba) under the following conditions. .

(CAPA-700 main unit setting)
Calculation method: Volume-based settling distance: ΔX = 10 mm
Absorption coefficient correction: No correction

<Bisazo organic pigment: CAPA-700 measurement conditions>
Solvent Ethanol DISP. VISC. 1.20 mPa · s
DISP. DENS. 0.79g / cc
SAMP. DENS. 1.20g / cc
D (MAX) 1.00μm
D (MIN) 0.10 μm
D (DIV) 0.05 μm
SPEED 7000rpm

<Phthalocyanine organic pigment: CAPA-700 measurement conditions>
Solvent Ethanol DISP. VISC. 1.20 mPa · s
DISP. DENS. 0.79g / cc
SAMP. DENS. 1.50 g / cc
D (MAX) 1.00μm
D (MIN) 0.10 μm
D (DIV) 0.05 μm
SPEED 7000rpm

Further, the electrophotographic photosensitive member formed by using the electrophotographic photoreceptor coating solution obtained by the preparation method of the present invention is produced by laminating at least an undercoat layer and a photosensitive layer on an electroconductive substrate . Even if this photosensitive layer is a single-layer type photosensitive layer (FIG. 1A) containing the charge transport material and the charge generation material in the same layer, the charge generation layer containing the charge generation material and the charge transport material are separated. It may be a laminated type (functionally separated type) photosensitive layer (FIG. 1B) separated into a charge transport layer contained therein. However, a laminated photosensitive layer is preferable from the viewpoint of electrophotographic characteristics. 1A and 1B, reference numeral 101 denotes a support, 102 denotes an undercoat layer, 103 denotes a photosensitive layer, 104 denotes a charge generation layer, and 105 denotes a charge transport layer. In the following, an electrophotographic photoreceptor containing a laminated (functionally separated type) photosensitive layer will be described in detail.

  The conductive support only needs to have conductivity, and examples thereof include metals such as aluminum, stainless steel, and nickel, or metals provided with a conductive layer, plastics, paper, and the like. Can be mentioned. In particular, cylindrical aluminum is excellent in terms of mechanical strength, electrophotographic characteristics, and cost. These conductive supports may be used as they are, but those subjected to physical treatment such as cutting and honing, anodizing treatment, or chemical treatment using acid or the like may be used. Among them, by performing physical processing such as cutting or honing, the surface roughness is processed to be 0.1 μm or more and 3.0 μm or less in terms of Rz value, thereby providing an interference fringe prevention function.

An interference fringe preventing layer (not shown in FIG. 1) may be provided between the conductive support and the undercoat layer. The interference fringe prevention layer is not necessary when the support itself has an interference fringe prevention function, but by using the conductive support as it is and forming an interference fringe prevention layer by coating on it, An interference fringe preventing function can be imparted to the conductive support by a simple method. For this reason, it is very useful in terms of productivity and cost. The preferred method of forming the interference fringe preventing layer, tin oxide, indium oxide, titanium oxide, paper and inorganic particles dispersed in a suitable solvent together with a curable resin such as phenol resin regulating a coating solution such as barium sulfate, Examples thereof include a method of coating and drying the conductive support. The thickness of the interference fringe prevention layer is preferably 1 μm or more and 40 μm or less.

  On the support or the interference fringe prevention layer, an undercoat layer is necessary for ensuring adhesion to the support, protecting the photosensitive layer from electrical breakdown, improving the carrier injection property of the photosensitive layer, and the like.

  The undercoat layer is formed by applying the above-described electrophotographic photosensitive member coating solution composed of an organic pigment and a polyamide resin on the conductive support or the interference fringe prevention layer. The film thickness is preferably 0.01 μm or more and 30 μm or less, and more preferably 0.1 μm or more and 20 μm or less. By including the organic pigment in the undercoat layer, it is possible to suppress density unevenness in the output image of the electrophotographic photosensitive member using the coating solution for the electrophotographic photosensitive member during continuous printing.

As the charge generation material, azo pigments such as monoazo, bisazo, trisazo, and tetrakisazo, phthalocyanine pigments such as gallium phthalocyanine and titanyl phthalocyanine, and perylene pigments can be used. A gallium phthalocyanine pigment is preferable from the viewpoint of characteristic stability due to environmental fluctuations. More preferably, from the viewpoints of high sensitivity and optical memory characteristics, strong peaks at Bragg angles 2θ = 7.4 ° ± 0.3 ° and 2θ = 28.2 ° ± 0.3 ° in CuKα characteristic X-ray diffraction It is a hydroxygallium phthalocyanine crystal having a crystal form .

  The coating solution for the charge generation layer is prepared by the above-described known dispersion method using the above-described charge generation material as a suitable solvent. Suitable solvents include, for example, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, ethyl acetate, methanol, methyl cellosolve, acetone, dioxane and N, N-dimethylformamide. At this time, a polymer substance may be added together as a binder, or the binder may be added after being dispersed in advance only with a pigment and a solvent.

  The binder can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, and polyvinyl porene. Preferred examples include insulating resins such as polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, and polyacrylamide resin. In addition, insulating resins such as polyamide, polyvinyl pyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone can be given.

  The charge generation layer is formed by applying a dispersion containing the above substances on the undercoat layer, and the film thickness is preferably 5 μm or less, and particularly preferably 0.05 μm or more and 1 μm or less.

  The charge transport layer is formed by applying and drying a paint in which a charge transport material and a binder are mainly dissolved in a solvent.

  Examples of the charge transport material used include various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triallylmethane compounds. A binder may be added after preliminarily dispersing and dissolving only with the charge transport material and the solvent. Moreover, what was mentioned above can be used as a binder.

  The thickness of the charge transport layer is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 30 μm or less.

  When the charge transport layer is a single layer, it can be formed similarly using the above-described substances, and the film thickness is preferably 5 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less.

  In the present invention, a protective layer may be provided on the charge transport layer for the purpose of improving durability, transferability and cleaning properties.

  The protective layer can be formed by applying and drying a protective layer coating solution obtained by dissolving a resin in an organic solvent. Examples of the resin include polyvinyl butyral, polyester, polycarbonate, polyamide, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, and styrene-acrylonitrile copolymer.

  Further, in order to provide the protective layer with the charge transport ability, the protective layer may be formed by curing a monomer material having a charge transport ability or a polymer type charge transport material using various crosslinking reactions. . Examples of the curing reaction include radical polymerization, ionic polymerization, thermal polymerization, photopolymerization, radiation polymerization (electron beam polymerization), plasma CVD method, and photo CVD method.

  Furthermore, you may include electroconductive particle, a ultraviolet absorber, an abrasion resistance improving agent, etc. in a protective layer. As the conductive particles, for example, metal oxides such as tin oxide particles are preferable. As the wear resistance improver, fluorine resin fine powder, alumina, silica and the like are preferable.

  The thickness of the protective layer is preferably 0.5 μm or more and 20 μm or less, and particularly preferably 1 μm or more and 10 μm or less.

  As a coating method for these various layers, a dipping method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, and the like can be used.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, embodiments of the present invention are not limited to these. Further, “parts” in the examples mean “parts by mass”.

In this example, ethanol, isopropanol, and 2-butanol are manufactured by Kishida Chemical, and special grades are used, and n-propanol, n-butanol, and propylene glycol monomethyl ether are manufactured by Kishida Chemical, grade 1. Further, the phthalocyanine pigment of the formula (2) is a crystal having strong peaks at positions of flag angles 2θ = 7.4 ° ± 0.3 ° and 2θ = 28.2 ° ± 0.3 ° in CuKα characteristic X-ray diffraction. phthalocyanine crystal forms using (described in Patent No. 3,639,691 Publication).

First, a method for preparing a polyamide resin sample used in the method for preparing a coating solution for an electrophotographic photoreceptor of the present invention will be described.

<Preparation Example 1>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 150 parts ethanol 850 parts

  In the above configuration, N-methoxymethylated 6 nylon resin was dissolved by heating at 70 ° C., and the solution filtered with a polyflon filter (PF020, pore size 2 μm, manufactured by Advantech Toyo Co., Ltd.) was sealed in a sealed container at 23 ° C. in an environment of 24 ° C. Stored still for hours. Thereafter, a liquid-solid determination test was performed based on ASTM D 4359-90 to prepare a gelled polyamide resin 1-1A as a solid.

  Moreover, the state of this gelled polyamide resin 1-1A was evaluated qualitatively by visual observation. The evaluation result was defined as “white gel” when the gelled polyamide resin had a white turbid appearance and lost fluidity. The results are shown in Table 1.

<Preparation Example 2>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 150 parts n-propanol 850 parts

  With the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a solid gelled polyamide resin 1-2A was obtained. Prepared and evaluated in the same manner as in Preparation Example 1. The results are shown in Table 1.

<Preparation Example 3>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 100 parts n-butanol 900 parts

  With the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a gelled polyamide resin 1-3A that was a solid was obtained. Prepared and evaluated in the same manner as in Preparation Example 1. The results are shown in Table 1.

<Preparation Example 4>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 100 parts Isopropanol 900 parts

  With the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a gelled polyamide resin 1-4A that was a solid was obtained. Prepared and evaluated in the same manner as in Preparation Example 1. The results are shown in Table 1.

<Preparation Example 5>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 100 parts 2-butanol 900 parts

  In the above configuration, dissolution, filtration, and storage in the same manner as in Preparation Example 1 were performed, and a liquid-solid determination test was performed based on ASTM D 4359-90, and a gelled polyamide resin 1-5A that was a solid was obtained. Prepared and evaluated in the same manner as in Preparation Example 1. The results are shown in Table 1.

<Preparation Example 6>
Nylon 6-66-610-12 Quaternary nylon copolymer resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) 150 parts Ethanol 850 parts

  With the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a gelled polyamide resin 1-6A that was a solid was obtained. Prepared and evaluated in the same manner as in Preparation Example 1. The results are shown in Table 1.

<Preparation Example 7>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 150 parts ethanol 850 parts

  In the above configuration, N-methoxymethylated 6 nylon resin was dissolved by heating at 70 ° C., and the solution filtered with a polyflon filter (PF020, pore size 2 μm, manufactured by Advantech Toyo Co., Ltd.) was 1 in an environment of 23 ° C. in a sealed container. Stored still for hours. A liquid-solid determination test was performed based on ASTM D 4359-90 to prepare a non-gelling polyamide resin sample 1-1B as a liquid.

  Further, the state of the non-gelled polyamide resin sample 1-1B was qualitatively evaluated by visual observation. As a result of the evaluation, an ungelatinized polyamide resin having a transparent appearance and a liquid state was defined as a “transparent liquid”. The results are shown in Table 1.

<Preparation Example 8>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 150 parts n-propanol 850 parts

  In the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a non-gelled polyamide resin 1-2B was obtained. Prepared and evaluated in the same manner as in Preparation Example 7. The results are shown in Table 1.

<Preparation Example 9>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 100 parts n-butanol 900 parts

  With the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a non-gelled polyamide resin 1-3B was obtained. Prepared and evaluated in the same manner as in Preparation Example 7. The results are shown in Table 1.

<Preparation Example 10>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 100 parts Isopropanol 900 parts

  In the above configuration, dissolution, filtration, and stationary storage are performed in the same manner as in Preparation Example 1, a liquid-solid determination test is performed based on ASTM D 4359-90, and a non-gelled polyamide resin 1-4B that is a liquid is obtained. Prepared and evaluated in the same manner as in Preparation Example 7. The results are shown in Table 1.

<Preparation Example 11>
N-methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Corporation, methoxymethylation rate 36.1%) 100 parts 2-butanol 900 parts

  In the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a non-gelled polyamide resin 1-5B was obtained. Prepared and evaluated in the same manner as in Preparation Example 7. The results are shown in Table 1.

<Preparation Example 12>
Nylon 6-66-610-12 Quaternary nylon copolymer resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) 150 parts Ethanol 850 parts

  In the above configuration, dissolution, filtration, and stationary storage were performed in the same manner as in Preparation Example 1, a liquid-solid determination test was performed based on ASTM D 4359-90, and a non-gelled polyamide resin 1-6B was obtained. Prepared and evaluated in the same manner as in Preparation Example 7. The results are shown in Table 1.

表１から明らかなように、調製例１〜６ではＡＳＴＭ Ｄ ４３５９−９０に基づき液体―固体判定試験を行い、固体であったことから、調製例１〜６のポリアミド樹脂試料はゲル化させたポリアミド樹脂である。また、調製例７〜１２ではＡＳＴＭ Ｄ ４３５９−９０に基づき液体―固体判定試験を行い、液体であったことから、調製例７〜１２のポリアミド樹脂試料はゲル化していないポリアミド樹脂である。また、定性的外観においてもゲル化させたポリアミド樹脂は白色の色味で流動性が失われており、ゲル化していないポリアミド樹脂は透明の色味で流動性がある。

As apparent from Table 1, the liquid on the basis of the Preparation Example 1-6 In the ASTM D 4359-90 - perform solid determination test, since was a solid, polyamide resin sample of tone made Examples 1 to 6 and gelled Polyamide resin. The liquid based on ASTM D 4359-90 in Preparation Example 7-12 - perform solid determination test, since was a liquid, polyamide resin sample of tone made examples 7-12 are polyamide resin which is not gelled. Moreover, in the qualitative appearance, the gelled polyamide resin has a white color and fluidity is lost, and the non-gelled polyamide resin has a transparent color and fluidity.

  Next, preparation and evaluation of a coating solution for an electrophotographic photoreceptor using the polyamide resin sample prepared above will be described.

<Examples 1-14, Comparative Examples 1-7>
The structure common to Examples 1-14 and Comparative Examples 1-7 is as follows.

Polyamide resin sample corresponding to Table 2 Amount (parts) corresponding to Table 2
Ethanol Amount (parts) corresponding to Table 2
500 parts of glass beads (GB201M, manufactured by Potters Barotini)
Organic pigments corresponding to Table 2 Amounts (parts) corresponding to Table 2
Solvent for dilution A The amount corresponding to the type corresponding to Table 2 (parts)
Dilution Solvent B Types corresponding to Table 2 (parts)

With the above configuration, some polyamide resin samples corresponding to Table 2 are gelled, so that they were crushed to a size of 2 mm or less by crushing with a sieve (mesh opening 2.0 mm) in advance. . Next, using an 800 ml scale batch type vertical sand mill (K-800, manufactured by Kanada Rika Kogyo Co., Ltd., disk diameter: 7 cm, number of disks: 5, cooling water temperature: 18 ° C.), polyamide resin corresponding to crushed Table 2 A sample, ethanol corresponding to Table 2, and glass beads were added. Subsequently, the dispersion was performed at 1400 rpm for 30 minutes to obtain a polyamide resin dispersion corresponding to Table 3. The volume average particle diameter (D ₅₀ ) of the polyamide resin dispersion corresponding to Table 3 was measured using “MICROTRAC PARTICLE-SIZE ANALYZER 9340 UPA” (manufactured by Leeds & Northrup) using the dynamic light scattering method as a measurement principle. The results are shown in Table 3.

  Next, an organic pigment of the following formula (1) or (2) was added to the polyamide resin dispersion corresponding to Table 3 as shown in Table 2. After further dispersion for 240 minutes, glass beads were added using a nylon mesh (material nylon 66, mesh size 200 mesh) while adding a dilution solvent that is a mixture of dilution solvent A and dilution solvent B corresponding to Table 2. Removal. Further, it was filtered through a polyflon filter (PF020, pore size 2 μm, manufactured by Advantech Toyo Co., Ltd.) to obtain a coating solution for an electrophotographic photosensitive member corresponding to Table 3.

Incidentally, phthalocyanine pigments exemplified as below following formula (2) is a hydroxy gallium phthalocyanine pigment. This pigment has a strong peak at 2θ = 7.4 ° ± 0.3 ° and 2θ = 28.2 ° ± 0.3 ° when the diffraction angle is θ in the chart obtained from CuKα characteristic X-ray diffraction. It is preferable that it is a hydroxygallium phthalocyanine crystal having a crystal form .

  Using an centrifugal sedimentation type particle size distribution measuring apparatus CAPA-700 (manufactured by Horiba Seisakusho), the average particle diameter (median diameter) and specific surface area of the organic pigment in the coating solution for electrophotographic photoreceptors corresponding to Table 3 were measured. The results are shown in Table 3.

  An electrophotographic photoreceptor coating solution corresponding to Table 3 was placed in a stoppered graduated cylinder (capacity 10 ml) so that the liquid level was 50 mm. These were allowed to stand for 1 month and 3 months in an environment of 23 ° C. and an environment of 35 ° C. in which 1.5% by weight of water was added to the electrophotographic photosensitive member coating solution. And the liquid stability of the coating liquid for electrophotographic photoreceptors corresponding to Table 3 after standing for 1 month and after standing for 3 months was visually evaluated. The evaluation result was set to “no sedimentation” when separation of the organic pigment was not observed. “Slightly settled” indicates that organic pigments are separated at a position of about 1 mm from the liquid level, “slightly settled” indicates that organic pigments are separated at a position of about 3 mm from the liquid level. “Sedimentation” was defined as organic pigment separation at a position lower than 10 mm from the surface height. The results are shown in Table 3.

Furthermore it is then, using the electrophotographic photoreceptor coating solution obtained above was prepared an electrophotographic photosensitive member corresponding to Table 3 based on the following configuration.

Titanium oxide powder coated with tin oxide (trade name Kronos ECT-62, manufactured by Titanium Industry Co., Ltd.) 50 parts resol type phenol resin 25 parts methyl cellosolve 20 parts spherical silicone resin powder (trade name Tospearl 120, manufactured by Toshiba Silicone) 3 .8 parts methanol 5 parts silicone oil (polydimethylsiloxane / polyoxyalkylene copolymer, average molecular weight 3000) 0.002 parts

  With the above configuration, the coating solution for interference fringe prevention layer was prepared by dispersing for 2 hours in a sand mill using glass beads having a diameter of 0.8 mm. This coating solution was dip-coated on an aluminum cylinder (diameter 30 mm, drawn tube) as a conductive support and dried at 140 ° C. for 30 minutes to form an interference fringe preventing layer having a thickness of 15 μm.

  On the obtained interference fringe preventing layer, an electrophotographic photoreceptor coating solution corresponding to Table 3 was dip coated and dried at 100 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.5 μm. .

  Next, 10 parts of the hydroxygallium phthalocyanine of the above formula (2), 0.1 part of the compound represented by the following formula (5), and polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) Add 5 parts to 250 parts of cyclohexanone. These were dispersed in a sand mill apparatus using glass beads having a diameter of 0.8 mm for 3 hours.

  To this, 100 parts of cyclohexanone and 450 parts of ethyl acetate were further added and diluted to obtain a charge generation layer coating solution. The obtained coating solution was dip-coated on the undercoat layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.16 μm.

  The hydroxygallium phthalocyanine used was 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° of Bragg angles (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction. And a crystal form having a strong peak at 28.3 °.

Next, 10 parts of a charge transport material represented by the following formula (6) and 10 parts of a polycarbonate resin (trade name: Iupilon Z-200, manufactured by Mitsubishi Engineering Plastics) were dissolved in 70 parts of monochlorobenzene. The obtained solution was dip-coated on the charge generation layer and dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 25 μm, and an electrophotographic photoreceptor corresponding to Table 3 was produced .

  The presence or absence of coating defects on the electrophotographic photoreceptor corresponding to Table 3 was evaluated by visual inspection. The evaluation result was defined as “no defects” when no foreign matter was observed on the coated surface of the electrophotographic photosensitive member corresponding to Table 3. In addition, the case where 1 to 10 foreign matters are recognized on the coated surface of the electrophotographic photosensitive member corresponding to Table 3 is “defect”, and the foreign surface is 10 or larger on the coated surface of the electrophotographic photosensitive member corresponding to Table 3. What was recognized was defined as “many defects”. The electrophotographic photosensitive member corresponding to Table 3 was recognized as “whitening” when white unevenness was observed, and the electrophotographic photosensitive member corresponding to Table 3 as “film thickness unevenness”. The results are shown in Table 3.

<Comparative Examples 9-15>
The configuration common to Comparative Examples 9 to 15 is as follows.

Polyamide resin sample corresponding to Table 2 Amount (parts) corresponding to Table 2
Ethanol Amount (parts) corresponding to Table 2
Glass beads (GB201M, Potters Barotini Co., Ltd.) 500 parts Organic pigment corresponding to Table 2 Amount (parts) corresponding to Table 2
Solvent for dilution A The amount corresponding to the type corresponding to Table 2 (parts)
Dilution Solvent B Types corresponding to Table 2 (parts)

  With the above configuration, the polyamide resin sample corresponding to Table 2 was crushed into a size of 2 mm or less by filtering while preliminarily crushing with a sieve (mesh opening 2.0 mm). Subsequently, an 800 ml scale batch type vertical sand mill apparatus (K-800, manufactured by Kanada Rika Kogyo Co., Ltd., disk diameter: 7 cm, number of disks: 5, cooling water temperature: 18 ° C.) is used. The crushed polyamide resin sample corresponding to Table 2, ethanol corresponding to Table 2, organic pigments corresponding to Table 2, and glass beads were put into this sand mill apparatus. After dispersion at 270 minutes at 1400 rpm, while adding a dilution solvent that is a mixture of the dilution solvent A and the dilution solvent B corresponding to Table 2, a nylon mesh (material nylon 66, using a mesh of 200 mesh) Further, the solution was filtered through a polyflon filter (PF020, pore size 2 μm, manufactured by Advantech Toyo Co., Ltd.) to obtain a coating solution for an electrophotographic photoreceptor corresponding to Table 3.

  Next, in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 7, the average particle diameter (median diameter) and specific surface area of the organic pigment of the coating solution for electrophotographic photoreceptor corresponding to Table 3 were measured. In addition, in Table 3 after standing for 1 month in a 23 ° C environment and in a 35 ° C environment in which 1.5% by weight of water was added to the electrophotographic photosensitive member coating solution corresponding to Table 3, The liquid stability of the corresponding coating solution for electrophotographic photosensitive member was visually evaluated. The results are shown in Table 3.

Furthermore Following, Examples 1 to 14, in the same manner as in Comparative Example 1-7, using an electrophotographic photoreceptor coating solution corresponding to Table 3, to produce an electrophotographic photosensitive member corresponding to Table 3, visually, Table The presence or absence of coating defects on the electrophotographic photosensitive member corresponding to 3 was visually evaluated. The results are shown in Table 3.

<Example 1 5 and the ratio Comparative Examples 8>
The configuration common to Example 15 and Comparative Example 8 is as follows.

Polyamide resin sample corresponding to Table 2 Amount (parts) corresponding to Table 2
Ethanol Amount (parts) corresponding to Table 2
Zirconia beads (Φ0.5mm YTZ ball, manufactured by Nikkato Corporation, YTZ is a trademark of Nikkato Corporation) 432g
Organic pigments corresponding to Table 2 Amounts (parts) corresponding to Table 2
Solvent for dilution A The amount corresponding to the type corresponding to Table 2 (parts)
Dilution Solvent B Types corresponding to Table 2 (parts)

With the above configuration, Φ0.5 mm zirconia beads were put into a 432 g vessel in a horizontal sand mill (MiniCea, manufactured by Ashizawa Finetech Co., Ltd., separator screen 0.3 mm, cooling water temperature 10 ° C.). A polyamide resin sample corresponding to Table 2 previously crushed to a size of 1 mm or less by crushing with a sieve (mesh opening 1.0 mm) and ethanol corresponding to Table 2 are circulating tanks. It was thrown into. Next, while the inside of the circulation tank was agitated, the dispersion was dispersed in 3 passes at a liquid feed rate of 100 ml / min and a disperser rotation speed of 2000 rpm, to obtain a polyamide resin dispersion corresponding to Table 3. The volume average particle diameter (D ₅₀ ) of the polyamide resin dispersion corresponding to Table 3 was measured using “MICROTRAC PARTICLE-SIZE ANALYZER 9340 UPA” (manufactured by Leeds & Northrup) using the dynamic light scattering method as a measurement principle. The results are shown in Table 3.

  Next, an organic pigment corresponding to Table 2 is added to the polyamide resin dispersion corresponding to Table 3, and further, while the inside of the circulation tank is stirred, the liquid feed rate is 100 ml / min, while circulating at a disperser rotation speed of 2000 rpm for 360 minutes. Distributed. Thereafter, a dilution solvent that is a mixture of the dilution solvent A and the dilution solvent B corresponding to Table 2 was added, and the mixture was filtered through a polyflon filter (PF020, pore size 2 μm, manufactured by Advantech Toyo Corporation) to correspond to Table 3. A coating solution for an electrophotographic photoreceptor was obtained.

  Next, in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 7, the average particle diameter (median diameter) and specific surface area of the organic pigment of the coating solution for electrophotographic photoreceptor corresponding to Table 3 were measured. In addition, in Table 3 after standing for 1 month in a 23 ° C environment and in a 35 ° C environment in which 1.5% by weight of water was added to the electrophotographic photosensitive member coating solution corresponding to Table 3, The liquid stability of the corresponding coating solution for electrophotographic photosensitive member was visually evaluated. The results are shown in Table 3.

Furthermore Following the same manner as in Examples 1 to 14 and Comparative Examples 1 to 7, using the electrophotographic photoreceptor coating solution corresponding to Table 3, to produce an electrophotographic photosensitive member corresponding to Table 3, visually, Table The presence or absence of coating defects on the electrophotographic photosensitive member corresponding to 3 was visually evaluated. The results are shown in Table 3.

<Comparative Example 16>
The configuration in Example 16 is as follows.

Polyamide resin sample corresponding to Table 2 Amount (parts) corresponding to Table 2
Ethanol Amount (parts) corresponding to Table 2
Zirconia beads (Φ0.5mm YTZ ball, manufactured by Nikkato Corporation, YTZ is a trademark of Nikkato Corporation) 432g
Organic pigments corresponding to Table 2 Amounts (parts) corresponding to Table 2
Solvent for dilution A The amount corresponding to the type corresponding to Table 2 (parts)
Dilution Solvent B Types corresponding to Table 2 (parts)

  With the above configuration, Φ0.5 mm zirconia beads were put into a 432 g vessel in a horizontal sand mill (MiniCea, manufactured by Ashizawa Finetech Co., Ltd., separator screen 0.3 mm, cooling water temperature 10 ° C.). Here, while crushing with a sieve (mesh opening 1.0 mm), a polyamide resin sample corresponding to Table 2 previously crushed to a size of 1 mm or less by filtering, ethanol corresponding to Table 2, Table 2 The organic pigment corresponding to was put into the circulation tank. While stirring in the circulation tank, the solution was dispersed while circulating at a liquid feed rate of 100 ml / min and a disperser rotation speed of 2000 rpm for 360 minutes. Thereafter, a dilution solvent that is a mixture of the dilution solvent A and the dilution solvent B corresponding to Table 2 was added, and the mixture was filtered through a polyflon filter (PF020, pore size 2 μm, manufactured by Advantech Toyo Corporation) to correspond to Table 3. A coating solution for an electrophotographic photoreceptor was obtained.

  Next, in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 7, the average particle diameter (median diameter) and specific surface area of the organic pigment of the coating solution for electrophotographic photoreceptor corresponding to Table 3 were measured. In addition, in Table 3 after standing for 1 month in a 23 ° C environment and in a 35 ° C environment in which 1.5% by weight of water was added to the electrophotographic photosensitive member coating solution corresponding to Table 3, The liquid stability of the corresponding coating solution for electrophotographic photosensitive member was visually evaluated. The results are shown in Table 3.

Furthermore Following the same manner as in Examples 1 to 14 and Comparative Examples 1 to 7, using the electrophotographic photoreceptor coating solution corresponding to Table 3, to produce an electrophotographic photosensitive member corresponding to Table 3, visually, Table The presence or absence of coating defects on the electrophotographic photosensitive member corresponding to 3 was visually evaluated. The results are shown in Table 3.

The following can be seen from Tables 2 and 3. Examples 1 to 6, 14, and 15 using a gelled polyamide resin were compared with Comparative Examples 1 to 8 using a non-gelled polyamide resin. Then, the Microtrac UPA volume average particle diameter (D ₅₀ ) of the polyamide resin dispersions of Examples 1 to 6, 14, and 15 is 0.58 μm or more regardless of the type of alcohol used in the polyamide resin sample. . This is clearly larger than the Microtrac UPA volume average particle size (D ₅₀ ) of 0.02 μm of the polyamide resin dispersions of Comparative Examples 1 to 8 using the same type of alcohol.

Microtrac UPA volume average particle diameter (D ₅₀₎ may be any less than 0.50 .mu.m 6.00Myuemu, none of the examples 1～6,14,15 in this range.

Also, the median diameter and Sw of the organic pigment of an electrophotographic photoreceptor coating solution in Example 1～6,14及beauty 15, as compared with Comparative Example 1-8, clearly median size is small, Sw is very Big. The coating solutions for electrophotographic photoreceptors of Examples 1 to 6, 14, and 15 are clearly superior also in stability in the stationary test.

  Furthermore, no defects were found in the visual evaluation of the electrophotographic photoreceptors to which the coating solutions for electrophotographic photoreceptors of Examples 1 to 6, 14, and 15 were applied. From this, the electrophotographic photosensitive member coating solutions of Examples 1 to 6, 14, and 15 in which the pregelled polyamide resin and the alcohol are dispersed are used for the electrophotographic photosensitive member measured by the centrifugal sedimentation method. The average particle diameter (median diameter) of the organic pigment in the coating solution is extremely small. It can also be seen that the coating solution for electrophotographic photosensitive member has a particularly large specific surface area and high stability.

  In Examples 1 to 6, 14, and 15 and Comparative Examples 9 to 16 using the gelled polyamide resin, the median diameter, Sw, and visual evaluation of the organic pigment of the electrophotographic photosensitive member coating solution were good. is there. However, in Examples 1 to 6, 14, and 15 in which the gelled polyamide resin and alcohol are previously dispersed with glass beads, the gel is allowed to stand for one month in an environment of 35 ° C. to which 1.5% by weight of water has been added. Thereafter, the liquid stability of the coating solution for an electrophotographic photoreceptor after standing for 3 months is good.

The coating solutions for electrophotographic photoreceptors of Examples 1 to 6, 14, and 15 in which the preliminarily gelled polyamide resin and the alcohol are dispersed have the following characteristics. First, the median diameter of the organic pigment in the electrophotographic photosensitive member coating solution measured by the centrifugal sedimentation method is 0.05 to 0.20 μm and very small. The specific surface area (Sw) is particularly large at 40 m ² / g or more and 85 m ² / g or less. From this, it can be seen that Examples 1 to 6, 14, and 15 are highly stable coating solutions for electrophotographic photoreceptors.

  In Examples 1 and 7 to 9, a coating solution for an electrophotographic photoreceptor is prepared by changing the mass ratio of the organic pigment and the polyamide resin. The median diameter and Sw of the organic pigment of the coating solution for an electrophotographic photoreceptor good from 5/2 to 1/100 of the mass ratio of the organic pigment to the polyamide resin are shown, but the mass ratio of the organic pigment to the polyamide resin is 5/2. Slight sedimentation was observed in the liquid state after standing for 3 months. From this, the electrophotographic photosensitive member coating solutions of Examples 1 and 7 to 9 in which the preliminarily gelled polyamide resin and the alcohol are dispersed are applied to the electrophotographic photosensitive member measured values by the centrifugal sedimentation method. The median diameter of the liquid organic pigment is extremely small. It can also be seen that the coating solution for electrophotographic photosensitive member has a particularly large specific surface area and high stability.

  In Examples 1 and 10 to 13, a coating solution for an electrophotographic photosensitive member was prepared by changing the ratio of an alcohol and a solvent having a boiling point of less than 100 ° C. and an alcohol and a solvent having a boiling point of 100 ° C. or more contained in the coating solution for an electrophotographic photosensitive member. doing. An organic coating solution for an electrophotographic photosensitive member having a good mass ratio of an alcohol and a solvent having a boiling point of less than 100 ° C. to an alcohol and a solvent having a boiling point of 100 ° C. or more contained in the coating solution for an electrophotographic photosensitive member from 21/79 to 95/5 The median diameter and Sw of the pigment are shown. However, in the electrophotographic photosensitive member having a mass ratio of the alcohol / solvent having a boiling point of less than 100 ° C. and the alcohol / solvent having a boiling point of 100 ° C. or higher in Example 13 having a mass ratio of 21/79, there are many alcohols and solvents having a boiling point of 100 ° C. or higher. The film thickness nonuniformity by is observed. Further, in the electrophotographic photosensitive member having a mass ratio of the alcohol / solvent having a boiling point of less than 100 ° C. and the alcohol / solvent having a boiling point of 100 ° C. or higher in Example 10 of 95/5, whitening of the coating film due to moisture absorption during drying was observed. Yes. However, in any case, no defect is observed in the electrophotographic photosensitive member. From this, the coating liquid for electrophotographic photoreceptors of Examples 1 and 10-13 in which the gelled polyamide resin and the alcohol are dispersed are the coating liquids for electrophotographic photoreceptor in the measured values by the centrifugal sedimentation method. The median diameter of these organic pigments is extremely small. It can also be seen that the coating solution for electrophotographic photosensitive member has a particularly large specific surface area and high stability.

It is a figure which shows the structure of a photosensitive layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Support body 102 Undercoat layer 103 Photosensitive layer 104 Charge generation layer 105 Charge transport layer

Claims (13)

Preparing a polyamide resin obtained by gelation using the A alcohol and polyamide resin,
Step polyamide resin obtained by the gel is dispersed in a solvent, to the volume average particle size (D _50), prepare 6.00μm or less of the polyamide resin dispersions or 0.50μm in the measured value by the dynamic light scattering method When,
Adding and dispersing an organic pigment in the polyamide resin dispersion;
In the polyamide resin dispersion obtained by dispersing the organic pigment, the steps of, prepare an electrophotographic photoreceptor coating solution by adding a diluting solvent,
Process for the preparation of an electrophotographic photoreceptor coating solution have a. The dilution solvent, ethanol, isopropanol, n- propanol, n- butanol, 2-butanol, electrons according to 請 Motomeko 1 Ru least Tsudea selected from the group consisting of isobutanol and propylene glycol monomethyl ether A method for preparing a coating solution for a photographic photoreceptor. The organic pigment contained in the electrophotographic photoreceptor coating solution has an average particle size of 0.05 or more and 0.20 μm or less, and the specific surface area of the organic pigment contained in the electrophotographic photoreceptor coating solution. (Sw) is a process for preparing an electrophotographic photoreceptor coating solution according to claim 1 or 2 ^{40 m} 2 / g or more ^85m 2 / g or less. The polyamide resin is an electrophotographic photoreceptor according to any one of 請 Motomeko 1-3 Ru quaternary nylon copolymer der of N- methoxymethylated nylon 6 or nylon 6-66-610-12 Preparation method of coating liquid. It said alcohol is a process for preparing an electrophotographic photoreceptor coating solution according to any one of Ah Ru請 Motomeko 1-4 carbon atoms in the alcohol having 1 to 6 linear or branched chain. Wherein the alcohol is ethanol, isopropanol, n- propanol, n- butanol, and at least Tsudea Ru請 Motomeko 5 process for the preparation of an electrophotographic photoreceptor coating solution according to selected from the group consisting of 2-butanol. The organic pigment is a phthalocyanine Pigment or process for the preparation of an electrophotographic photoreceptor coating solution according to any one of 請 Motomeko 1-6 Ru azo pigments der. The organic pigments are azo pigments, process for the preparation of an electrophotographic photoreceptor coating solution according to claim 7 wherein the azo pigment is an azo pigment represented by the following formula (1).

The organic pigment is a phthalocyanine pigment, and the phthalocyanine pigment has strong peaks at positions of Bragg angles 2θ = 7.4 ° ± 0.3 ° and 2θ = 28.2 ° ± 0.3 ° in CuKα characteristic X-ray diffraction . process for the preparation of an electrophotographic photoreceptor coating solution according to hydroxygallium phthalocyanine crystal der Ru請 Motomeko 7 crystalline form with. The weight ratio of the organic pigment and the polyamide resin is 1: 100 or more 2: method for the preparation of an electrophotographic photoreceptor coating solution according to 1 any one of the which claims 1 to 9 or less. In the step of dispersing by adding an organic pigment in engineering as及 beauty the polyamide resin dispersion, prepare the polyamide resin dispersion, the fixed container rotary stirring portion attached to a rotating shaft inserted from outside of the fixed container process for the preparation of an electrophotographic photoreceptor coating solution according to any one of claims 1 to 10 is a process using a sand mill having within. The sand mill, batch sand mill with Ah Ru請 Motomeko 11 process for the preparation of an electrophotographic photoreceptor coating solution according to the. In the method for producing an electrophotographic photoreceptor by laminating an undercoat layer and a photosensitive layer on a conductive support, a coating solution was prepared by the preparation method according to any one of claims 1 to 12 and prepared. A method for producing an electrophotographic photoreceptor, comprising forming the undercoat layer using the coating solution.

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