JP2000126638A - Preparation of liquid dispersion, electrophotographic photoreceptor, electrophotographic method, electrophotographic device and process cartridge for electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good dispersion stability by allowing the grains of a pigment to be wet-dispersed not to contain the grains of the sizes higher than a specified ratio of the media diameters and controlling the diameters of the liq. dispersion media below a specified value. SOLUTION: The grains of a pigment to be wet-dispersed do not contain the grains of >=1/2 of the media diameters (controlled to <1/2). In this case, the appropriate size of the solid dispersion media diameters is different between crushing and dispersing, and the diameters are selected in a completely opposite direction. When the solid dispersion media of <= about 2 mm are used the coarse crushing capacity is extremely decreased as compared with the case that the larger sizes are used. Accordingly, the pigment to be used is previously controlled to the size (<=1/2 of the media diameters) corresponding to the media diameters, and a stable dispersion method is given without obtaining the crushing capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a pigment dispersion, an electrophotographic photosensitive member produced by using the same, and an electrophotographic method, an electrophotographic apparatus and an electrophotographic apparatus using the electrophotographic photosensitive member. Regarding the process cartridge, in detail, a method for preparing an organic pigment dispersion having excellent dispersibility and crystal stability and good handling properties, and an electron having excellent stability of the charged potential and residual potential of the photoreceptor even after repeated use. Photographic photoreceptor, electrophotographic method using it,
The present invention relates to an electrophotographic apparatus and a process cartridge for the electrophotographic apparatus.

[0002]

BACKGROUND OF THE INVENTION Organic pigments have been used as fillers in paints for a relatively long time. In particular, the richness of the color is an advantage not found in inorganic pigments. In recent years, various materials and uses have been created as an application example of an organic pigment since it has been spotlighted as a material for an organic photoelectric conversion device.

[0003] In forming such a film containing an organic pigment, a wet film forming method, which can be easily enlarged, is predominant. It is no exaggeration to say that the quality of the coating film formed by the wet film formation method is almost completely affected by the quality of the dispersion liquid containing the pigment. The quality of the dispersion is determined by the dispersibility of the pigment. Thus, a good dispersion is one in which the pigment is sufficiently dispersed in the vehicle and the state of dispersion is maintained for a long time.

In order to produce such a dispersion, various dispersers and dispersion systems have been proposed so far, and methods for increasing the dispersion efficiency have been devised. In order to reduce the particle size of the pigment in the dispersion, a dispersion medium having a small size is generally used. However, if the pigment is difficult to disperse, the dispersing power is insufficient. The only way to improve this is to increase the media size or use a pigment that is easily dispersed. Since the former has a limit on the particle size to be finally reached, it is efficient to develop the latter method. However, there is almost no approach from the pigment side regarding dispersion.

On the other hand, the development of information processing system machines using the electrophotographic system has been remarkable. In particular, optical printers that convert information into digital signals and record information with light have significantly improved print quality and reliability. This digital recording technology is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, since a copier equipped with the digital recording technology in a conventional analog copy is added with various information processing functions, its demand is expected to increase more and more in the future.

At present, small, inexpensive and highly reliable semiconductor lasers (LDs) and light emitting diodes (LEDs) are widely used as light sources for optical printers. The emission wavelength of currently used LEDs is 660 nm, and L
The emission wavelength range of D is in the near infrared region. Therefore, development of an electrophotographic photosensitive member having high sensitivity from a visible light region to a near infrared light region is desired.

The photosensitive wavelength range of an electrophotographic photosensitive member is substantially determined by the photosensitive wavelength region of a charge generating substance used in the photosensitive member. Therefore, many charge generation substances such as various azo pigments, polycyclic quinone pigments, trigonal selenium, various phthalocyanine pigments, etc. have been developed. Among them, titanyl phthalocyanine (abbreviated as TiOPc) is 60
In order to show high sensitivity to long wavelength light from 0 to 800 nm,
It is extremely important and useful as a material for a photoreceptor for an electrophotographic printer or a digital copying machine in which a light source is an LED or LD.

The conditions of the electrophotographic photosensitive member repeatedly used in the Carlson process and similar processes include sensitivity, receiving potential, potential holding property, potential stability,
It is required that the electrostatic characteristics represented by the residual potential and the spectral characteristics be excellent. In particular, for high-sensitivity photoconductors, it has been empirically known that many photoconductors have a decrease in chargeability and an increase in residual potential due to repeated use, which govern the life characteristics of the photoconductor. This is no exception. Therefore, the stability of a photoreceptor using titanyl phthalocyanine by repeated use is not yet sufficient, and there has been an eager desire to complete the technology. Also, there has been a demand for the production of a dispersion liquid (photosensitive layer forming liquid) capable of stably producing a photoreceptor having these characteristics over a long period of time.

The organic photoreceptor is a so-called single-layer photoreceptor in which a photosensitive layer coating solution containing a charge generating substance, a charge transport substance, a binder resin and the like is formed on a conductive support by dip coating or the like. There is a laminated photoreceptor in which a charge generation layer is formed on a conductive support using a coating liquid containing a charge generation substance, and then a charge transport layer is formed using a coating liquid containing a charge transport substance. The laminated photoreceptor may be coated with an undercoat layer or a protective layer for the purpose of improving image quality or durability.

However, it cannot be said that there is no problem in electrostatic repetition characteristics of such a single-layer type electrophotographic photoreceptor or a multilayer type electrophotographic photoreceptor. There has been a problem that deterioration, in particular, the charging potential decreases, or the surface potential decreases during the time from charging to development, that is, so-called dark decay increases.

[0011]

An object of the present invention is to provide a method for efficiently preparing an organic pigment dispersion when preparing a dispersion using an organic pigment. Another object of the present invention is to provide a stable electrophotographic photoreceptor which does not cause a decrease in chargeability and an increase in residual potential even when repeatedly used without losing high sensitivity. Another object of the present invention is to provide an electrophotographic photoreceptor having improved abrasion resistance while maintaining the above characteristics. Another object of the present invention is to provide a stable electrophotographic method which does not cause a decrease in chargeability and a rise in residual potential even when repeatedly used without losing high sensitivity. Still another object of the present invention is to provide a stable electrophotographic apparatus and a process cartridge for the electrophotographic apparatus which do not cause a decrease in chargeability and an increase in residual potential even when repeatedly used without losing high sensitivity.

[0012]

Means for Solving the Problems The present inventors have considered the organic pigment dispersion as follows. That is, the dispersibility of the organic pigment can be roughly classified into the crushability and dispersion stability of the pigment. The latter is determined by factors such as wettability between pigment and vehicle, particle size, specific gravity difference between pigment and vehicle, and the like. The former is determined by the force applied to the pigment of the dispersion medium under certain dispersion conditions. This force differs depending on the dispersion method.For example, in a ball mill, a medium having a large weight and a large pot diameter is advantageous, and in a bead mill, an attritor, etc., a medium in which a rotating speed of a portion for moving the medium is advantageous is advantageous. Become. Generally speaking, the greater the specific gravity of the medium and the larger the diameter of the medium, the more advantageous the pulverization works.

On the other hand, the dispersion of the pigment involves a dispersion process following the pulverization of the pigment. The term “dispersion” refers to a state in which the pigment pulverized to some extent as described above sufficiently wets the vehicle and reaches an equilibrium state while repeating aggregation and redispersion. At this time, the pigment particles are dispersed in gaps between the media or gaps between the media and surrounding walls. Therefore, the smaller the media diameter, the smaller the porosity, the more the dispersion proceeds, and the smaller the final particle diameter of the pigment. Generally, when a dispersion is applied to form a coating film, the smaller the pigment particle size and the narrower the particle size distribution, the better the coating film can be obtained. Therefore, it is preferable that the diameter of the medium used for dispersion is small, but the disadvantage is that the crushability is inferior to that of the medium having a large diameter.

Further, as described above, organic pigments have recently been applied as photoelectric conversion materials, and materials exhibiting generally good properties have a strong cohesive force and a very strong secondary particle packing property. For this reason, it is very difficult to produce a good dispersion. In addition, even in the case of materials represented by the same chemical structural formula, there are many cases where only a specific crystal type expresses a specific function. Such a specific crystal type may be easily changed by a simple physical or mechanical stress other than the chemical stress. In such a case, it is not preferable to apply much physical / mechanical stress such as dispersion, and easy dispersion is a powerful means that can definitely exhibit a specific function.

Further, the present inventors have considered the electrophotographic photosensitive member as follows. That is, as described above, the organic pigment plays an important role as a photocarrier generating material of the electrophotographic photosensitive member. Organic pigments are generally present in the form of fine particles in an electrophotographic photosensitive member. This is because the image writing light in the electrophotographic process is uniformly absorbed at a constant rate. For this reason, if the particles are too large or the particle size distribution is sparse, the resulting electrophotographic photoreceptor not only does not form a clear coating on the photosensitive layer (charge generation layer) containing the organic pigment, but also exhibits abnormalities in the electrophotographic process. An image may be generated. In view of the above, it is preferable that the organic pigment as the charge generating substance has a narrow particle size distribution and a small particle size as much as possible in the dispersion for forming the photosensitive layer (charge generating layer). That is, it is no exaggeration to say that the preparation of a dispersion having high dispersion stability is the key to the success or failure of the electrophotographic photosensitive member.

The present invention relates to a method for producing a pigment dispersion exhibiting good dispersion stability, and a method for producing a dispersion while maintaining the crystallinity of the pigment used. Its features are:
By using a solid medium with the size of the area where sufficient dispersibility can be obtained and by controlling the pigment particle size before the wet dispersion is performed in advance, the pigment particle size in the dispersion can be adjusted. This is a method for producing a dispersion liquid that can be made as small as possible and can be dispersed very efficiently without changing the crystal form of the pigment during dispersion. Further, in the present invention, when a photoreceptor using a dispersion prepared by the above-described technique is used in an electrophotographic process, a reduction in chargeability and a reduction in photosensitivity (increase in residual potential) in repeated use, which have been a problem in the past, have been a problem. It was found that a stable surface potential was given without causing the occurrence of the surface potential. As a result, it has been found that the occurrence of abnormal images such as background contamination or image density reduction is suppressed, and the present invention has been completed.

Therefore, according to the present invention, first, when a pigment is wet-dispersed using a solid dispersion medium to prepare a dispersion, particles of the pigment subjected to the wet dispersion have a diameter of 1% of the media diameter. A method for preparing a dispersion, wherein the method does not include particles having a size of at least / 2 and the size of the solid dispersion medium is 2 mm or less in diameter.

Second, the diameter of the media used for wet dispersion is 1
The method for preparing the first dispersion liquid is provided, wherein the pigment containing no particles having a size of / 2 or more is dispersed by a dry method.

Third, the pigment which does not contain particles having a size equal to or more than １ ／ of the media diameter to be subjected to wet dispersion is classified by a sieve or the like, and the particle size is previously adjusted. A first or second method for preparing a dispersion is provided.

Fourthly, there is provided the method for producing a dispersion according to any one of the first to third aspects, wherein the disperser in the wet method is a bead mill.

Fifthly, there is provided a method for producing a dispersion according to any one of the first to fourth aspects, wherein the pigment is an organic pigment.

Sixth, there is provided a method for producing the fifth dispersion, wherein the organic pigment is a phthalocyanine pigment.

Seventh, there is provided a method for preparing the sixth dispersion, wherein the phthalocyanine pigment is titanyl phthalocyanine.

Eighth, the pigment in the wet dispersion is titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ of at least 27.2 ° ± 0.2 ° with respect to the characteristic X-ray of CuKα (wavelength 1.514 °). A method for producing a dispersion according to any one of the first to seventh aspects is provided.

Ninth, a photosensitive member having a photosensitive layer containing at least an organic pigment on a conductive support, wherein the photosensitive layer is dry-dispersed / pulverized or sieved prior to dispersion by a wet method. Layer formed by applying and drying a dispersion prepared by wet-dispersion using an organic pigment roughly pulverized to a size equal to or less than half the diameter of a solid dispersion medium used for wet-dispersion by a classification means according to An electrophotographic photosensitive member is provided.

Tenthly, there is provided the ninth electrophotographic photosensitive member, wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer.

Eleventh, there is provided the tenth electrophotographic photosensitive member, wherein the charge transport layer contains a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain.

Twelfth, there is provided an electrophotographic method in which at least charging, image exposure, development, transfer, cleaning, and charge elimination are repeatedly performed on an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is dispersed before the wet method dispersion. A dispersion prepared by wet dispersion using an organic pigment coarsely ground to a size of 1/2 or less of the solid dispersion medium diameter used for wet dispersion by a dry dispersion / pulverization means or a classification means such as a sieve is applied and dried. Thus, there is provided an electrophotographic method, wherein the electrophotographic photosensitive member is provided with a photosensitive layer formed on a conductive support.

A thirteenth aspect is an electrophotographic apparatus including at least a charging unit, an image exposing unit, a developing unit, a transferring unit, a cleaning unit, a discharging unit, and an electrophotographic photosensitive member. Prepared by wet dispersion using an organic pigment which has been coarsely pulverized to a size equal to or less than half the diameter of the solid dispersion medium used for wet dispersion by a dry dispersion / pulverization means or a classification means such as a sieve prior to the wet dispersion. An electrophotographic apparatus is provided, which is an electrophotographic photosensitive member in which a photosensitive layer formed by applying and drying the obtained dispersion is provided on a conductive support.

Fourteenth, a process cartridge for an electrophotographic apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is classified by a dry dispersing / pulverizing means or a sieve prior to wet dispersion. A photosensitive layer formed by applying and drying a dispersion prepared by wet dispersion using an organic pigment coarsely pulverized to a size equal to or less than 1/2 of the diameter of a solid dispersion medium used for wet dispersion by means of a conductive material is used. A process cartridge for an electrophotographic apparatus, wherein the process cartridge is an electrophotographic photosensitive member provided on a photosensitive support.

[0031]

Hereinafter, the present invention will be described in more detail. A general dispersion containing a pigment is prepared by adding the pigment to a solution in which a solvent or a binder resin is dissolved, and using an appropriate dispersing apparatus. As described above, the process of dispersing pigment particles can be divided into a process in which a relatively large soul is coarsely pulverized and a process in which relatively small particles become fine particles. The former is a process in which physical and mechanical actions are particularly large, and the process proceeds as the energy imparted to the pigment particles by the dispersion medium increases. On the other hand, in the latter process, the affinity between the vehicle and the pigment particles and the interaction between the pigment particles (aggregation and redispersion) start from the state where the particles have become somewhat smaller.
The chemical action is large. For this reason, it is empirically known from experiments by the inventors that changes in the crystal type and the like often occur in this process. In addition, the attained size of the pigment particles is
Depending on the media diameter, the smaller the media diameter, the smaller the void ratio and the smaller the particle size.

As described above, the appropriate size of the solid dispersion medium in the dispersion of the pigment by the wet method is completely different in the process of pulverization and dispersion, and the selection direction is completely reversed. However, since the final size of the pigment particles is a very important property for the dispersion, the media diameter must be selected from the smaller one. From this viewpoint, it is considered that the media diameter is desirably at least 2 mm or less, although it differs slightly depending on the distribution system.

By the way, as described above, when a solid dispersion medium of about 2 mm or less is used, the coarse pulverizing ability of the pigment is extremely deteriorated as compared with the case where a larger medium is used. For this reason, if the particle size of the pigment used is large, the media cannot not only crush the pigment particles, but in severe cases, the medium may be buried in the pigment particles and may even become a huge lump as it is. Therefore, by setting the pigment to be used to have a size (1/2 or less of the media diameter) according to the media size in advance, a dispersion method capable of performing stable dispersion without requiring a pulverizing ability is provided.

Several methods are conceivable in order to make the particle size of the pigment used for dispersion into a size corresponding to the media size. One suitable method is pulverization by a dry method. Examples of pulverization by a dry method include dry milling, a mixer, and a sand grinder. In any case, it may be selected depending on the kind and amount of the pigment used, the stability of the crystal, the heat resistance, and the like. The processing time is also selected according to the properties of the pigment. The dry method has an advantage that the phenomenon that the pigment particles become a large lump together with the medium as described above does not easily occur.

Further, it is also a powerful means that the effect of the present invention can be further enhanced by previously adjusting the size of the pigment particles coarsely pulverized by such a dry method. For example, if the sizes are made uniform by using a sieve or a mesh, the uniformity of the dispersion is exhibited more.

In the present invention, a stable dispersion state is provided to the pigment particles and the crystal form is not changed. Therefore, the above-described dispersion method is particularly effective for organic pigments.

As the organic pigment used in the electrophotographic photoreceptor produced in the present invention, any of known organic pigments can be used. Examples thereof include phthalocyanine pigments, monoazo pigments, disazo pigments, trisazo pigments, and perylene pigments. Pigments,
Perinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, squaric acid dyes, naphthalocyanine pigments, azurenium salt dyes and the like can be used.

[0038] Phthalocyanine pigments having a large number of crystal forms are very effective. Among them, titanyl phthalocyanine is a pigment whose properties vary greatly depending on the crystal form.
In particular, the maximum diffraction peak at a Bragg angle of 2θ for the characteristic X-ray (wavelength 1.514 °) of CuKα is 27.2 ° ±
Titanyl phthalocyanine at 0.2 ° has an extremely high photocarrier generation ability, but its crystal form is unstable and easily converted to another crystal form. However, in the present invention, a dispersion can be prepared while maintaining the crystal form stably, and an electrophotographic photoreceptor can be obtained while maintaining the original photocarrier generation ability of the pigment.

FIG. 1 is a sectional view showing an electrophotographic photosensitive member used in the present invention. A single-layer photosensitive layer 33 containing a charge generating material and a charge transport material as main components on a conductive support 31.
Is provided. 2 and 3 are cross-sectional views showing another example of the configuration of the electrophotographic photoreceptor used in the present invention. The charge generation layer 35 mainly composed of a charge generation material, and the electric charge mainly composed of a charge transport material are shown. The transport layer 37 has a stacked configuration.

The conductive support 31 has a volume resistance of 10
Those exhibiting a conductivity of ¹⁰ Ωcm or less, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver, metals such as platinum, tin oxide, metal oxides such as indium oxide, by evaporation or sputtering, Film or cylindrical plastic, coated with paper, or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc. and extruded, made into a tube by a method such as drawing, cutting, super finishing, polishing, etc. Surface-treated tubes and the like can be used. Further, an endless nickel belt and an endless stainless belt disclosed in JP-A-52-36016 can also be used as the conductive support 31.

In addition to the above, a support obtained by dispersing a conductive powder on a suitable binder resin on the above support and applying the same can also be used as the conductive support 31 of the present invention. As the conductive powder, carbon black, acetylene black, aluminum, nickel, iron, nichrome, copper, zinc,
Metal powder such as silver, or metal oxide powder such as conductive tin oxide and ITO can be used. Further, the binder resin used simultaneously, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer,
Styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral , Thermoplastic resins such as polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, thermosetting resin or photo-curing resin. can give. Such a conductive layer, these conductive powder and binder resin suitable solvent, for example, tetrahydrofuran, dichloromethane,
It can be provided by dispersing and applying in methyl ethyl ketone, toluene or the like.

Further, a conductive material is formed by a heat-shrinkable tube in which a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, or Teflon contains the conductive powder on a suitable cylindrical substrate. Those provided with a layer can also be favorably used as the conductive support 31 of the present invention.

Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a stacked layer, but for convenience of explanation, the case where the photosensitive layer is composed of the charge generation layer 35 and the charge transport layer 37 will be described first.

The charge generation layer 35 is a layer containing an organic pigment as a main component. This is a layer obtained by forming a film of the dispersion prepared by the method described above. Charge generation layer 35 if necessary
As the binder resin used for, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate,
Silicone resin, acrylic resin, polyvinyl butyral,
Polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, Cellulose-based resins, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like can be mentioned. The amount of the binder resin is suitably from 0 to 500 parts by weight, preferably from 10 to 300 parts by weight, per 100 parts by weight of the charge generating substance.

Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. No. The coating method of the coating solution includes dip coating, spray coating, beat coating, nozzle coating, spinner coating,
A method such as a ring coat can be used. The thickness of the charge generation layer 35 is suitably about 0.01 to 5 μm,
Preferably it is 0.1 to 2 μm.

The charge transporting layer 37 can be formed by dissolving or dispersing the charge transporting substance and the binder resin in a suitable solvent, applying the solution on the charge generating layer, and drying. Also,
If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

The charge transport material includes a hole transport material and an electron transport material. Examples of the charge transport material include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Examples thereof include electron accepting substances such as trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and benzoquinone derivatives.

Examples of the hole transport material include poly-N-vinylcarbazole and its derivatives, poly-γ-galvazolylethylglutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, polysilane, Oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives,
α-phenylstilbene derivative, benzidine derivative, diarylmethane derivative, triarylmethane derivative, 9
And other known materials such as -styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazine derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, and enamine derivatives. These charge transport materials are used alone or in combination of two or more.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polyacetic acid. Vinyl, polyvinylidene chloride, polyalate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin And a thermoplastic or thermosetting resin such as phenolic resin and alkyd resin.

The amount of the charge transporting substance is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, per 100 parts by weight of the binder resin.
Parts by weight are appropriate. The charge transport layer has a thickness of 5-1.
It is preferable that the thickness be about 00 μm. As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.

For the charge transporting layer, a polymer charge transporting substance having both a function as a charge transporting substance and a function as a binder resin is preferably used. The charge transport layer composed of these polymeric charge transport materials has excellent abrasion resistance. As the polymer charge transport material, known materials can be used, but polycarbonates containing a triarylamine structure in the main chain and / or side chain are preferably used. Among them, the polymer charge transport materials represented by the formulas (1) to (10) are preferably used, and these are exemplified below and specific examples are shown.

[0052]

Embedded imageWhere R₁, R_Two, R_ThreeAre each independently substituted or
Unsubstituted alkyl group or halogen atom, R_FourIs a hydrogen atom
Or a substituted or unsubstituted alkyl group, R_Five, R ₆Is replaced
Or an unsubstituted aryl group, o, p, and q are each independently
And an integer of 0 to 4, k and j represent compositions, and 0.1 ≦ k
≦ 1, 0 ≦ j ≦ 0.9, and n represents the number of repeating units.
It is an integer of 5000. X is an aliphatic divalent group, cyclic fat
Group represented by the following general formula or a divalent group represented by the following general formula:
You.

Embedded image In the formula, R ₁₀₁ and R ₁₀₂ each independently represent a substituted or unsubstituted alkyl group, aryl group or halogen atom.
l and m are integers from 0 to 4, Y is a single bond, and has 1 to 1 carbon atoms.
2 linear, branched or cyclic alkylene group, -O
-, - S -, - SO -, - SO 2 -, - CO -, - CO
—O—Z—O—CO— (wherein, Z represents an aliphatic divalent group) or

Embedded image In the formula, a is an integer of 1 to 20, b is an integer of 1 to 2000,
R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group. Here, R ₁₀₁ and R ₁₀₂ , R ₁₀₃ and R
₁₀₄ may be the same or different.

[0053]

Embedded image In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group, A
r ₁ , Ar ₂ and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of equation (1).

[0054]

Embedded image In the formula, R ₉ and R ₁₀ are a substituted or unsubstituted aryl group,
Ar ₄ , Ar ₅ and Ar ₆ represent the same or different arylene groups. X, k, j and n are the same as in the case of equation (1).

[0055]

Embedded image In the formula, R ₁₁ and R ₁₂ are a substituted or unsubstituted aryl group,
Ar ₇ , Ar ₈ and Ar ₉ are the same or different arylene groups, p
Represents an integer of 1 to 5. X, k, j and n are (1)
Same as for expressions.

[0056]

Embedded imageWhere R₁₃, R₁₄Is a substituted or unsubstituted aryl group,
Ar_Ten, Ar₁₁, Ar ₁₂Are the same or different arylene groups,
X₁, X_TwoIs a substituted or unsubstituted ethylene group, or
Alternatively, it represents an unsubstituted vinylene group. X, k, j and
n is the same as in the case of equation (1).

[0057]

Embedded image In the formula, R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ are a substituted or unsubstituted aryl group, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ and Ar ₁₆ are the same or different arylene groups, and Y ₁ , Y ₂ and Y ₃ are A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, and a vinylene group may be the same or different. X, k, j and n
Is the same as in the case of equation (1).

[0058]

Embedded image In the formula, R ₁₉ and R ₂₀ represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j and n are the same as in the case of equation (1).

[0059]

Embedded image In the formula, R ₂₁ is a substituted or unsubstituted aryl group, A
r ₂₀ , Ar ₂₁ , Ar ₂₂ and Ar ₂₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of equation (1).

[0060]

Embedded image In the formula, R ₂₂ , R ₂₃ , R ₂₄ , and R ₂₅ are a substituted or unsubstituted aryl group, Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ , Ar ₂₈
Represents the same or different arylene groups. X, k, j and n are the same as in the case of equation (1).

[0061]

Embedded imageWhere R₂₆, R₂₇Is a substituted or unsubstituted aryl group,
Ar₂₉, Ar₃₀, Ar ₃₁Represents the same or different arylene groups
Represent. X, k, j and n are the same as in the case of equation (1).
is there.

In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer 37. As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount of the plasticizer is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain are used in an amount of 0 to 1 weight based on the binder resin. % Is appropriate.

Next, the case where the photosensitive layer has a single-layer structure 33 will be described. The single-layer photosensitive layer is a charge generating substance, a charge transporting substance and a binder resin dispersed in a suitable solvent by the method described above,
This can be formed by coating and drying. Further, the photosensitive layer may be of a function-separated type to which the above-mentioned charge transport material is added, and can be used favorably. Also,
If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

As the binder resin, in addition to using the binder resin described above for the charge transport layer 37 as it is, the charge generation layer 3
The binder resins described in 5 may be mixed and used. Of course, the above-mentioned polymer charge transport materials can also be used favorably. The amount of the charge generating substance is preferably 5 to 40 parts by weight, and the amount of the charge transporting substance is 0 to 100 parts by weight of the binder resin.
190 parts by weight is preferable, and 50 to 150 parts are more preferable.
Parts by weight. The single-layer photosensitive layer is formed by dip coating or spraying a coating liquid obtained by dispersing a charge generating substance and a binder resin together with a charge transporting substance, if necessary, using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane using a dispersing machine or the like. It can be formed by coating with a coat or bead coat. The thickness of the single-layer photosensitive layer is suitably about 5 to 100 μm.

The electrophotographic photoreceptor of the present invention may have an undercoat layer between the conductive support 31 and the photosensitive layer. The undercoat layer generally contains a resin as a main component. However, considering that the photosensitive layer is coated thereon with a solvent, these resins are resins having high solvent resistance to general organic solvents. desirable. Examples of such a resin include water-soluble resins such as polyvinyl alcohol, casein and sodium polyacrylate, alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy resin. Curable resins that form a three-dimensional network structure, such as resins, are exemplified. Further, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moiré and reduce residual potential.

These undercoat layers can be formed by using an appropriate solvent and a coating method as in the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, the undercoat layer of the present invention, A1 ₂
O ₃ provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , Ti
Those provided with an inorganic substance such as O ₂ , ITO, CeO ₂ by a vacuum thin film forming method can also be used favorably. In addition, known materials can be used. The thickness of the undercoat layer is 0 to 5 μm
Is appropriate.

In the electrophotographic photosensitive member of the present invention, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. The material used for the protective layer is ABS resin, AC
S resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallyl sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyether sulfone, polyethylene, polyethylene terephthalate,
Polyimide, acrylic resin, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone,
Examples include resins such as polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Other protective layers include fluororesins such as polytetrafluoroethylene, silicone resins, and inorganic materials such as titanium oxide, tin oxide, and potassium titanate dispersed in these resins for the purpose of improving abrasion resistance. Can be added. As a method for forming the protective layer, an ordinary coating method is employed. The thickness of the protective layer is suitably about 0.1 to 10 μm. In addition to the above, a-C,
A known material such as a-SiC can be used as the protective layer.

In the present invention, an intermediate layer can be provided between the photosensitive layer and the protective layer. The intermediate layer generally uses a binder resin as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a normal coating method is employed as described above. In addition,
The thickness of the intermediate layer is suitably about 0.05 to 2 μm.

Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a schematic diagram for explaining the electrophotographic process and the electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.

In FIG. 4, the photosensitive member 1 is provided with a photosensitive layer formed on a conductive support by using the dispersion prepared by the above-described method. The photoconductor 1 has a drum shape, but may have a sheet shape or an endless belt shape. Charging charger 3, pre-transfer charger 7, transfer charger 10, separation charger 11,
Known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller are used for the pre-cleaning charger 13.

As the transfer means, the above-mentioned charger can be generally used, but as shown in the figure, a combination of a transfer charger and a separation charger is effective.

The light sources such as the image exposure section 5 and the neutralizing lamp 2 include a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, and a light emitting diode (LE).
D), semiconductor lasers (LD), electroluminescence (EL), and other general light-emitting materials can be used.
To irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used.

The light source and the like are provided with a transfer step, a charge removal step, a cleaning step, and a pre-exposure step using light irradiation in addition to the steps shown in FIG.
Light is applied to the photoconductor.

The toner developed on the photoreceptor 1 by the developing unit 6 is transferred to the transfer paper 9, but not all is transferred, and some toner remains on the photoreceptor 1. Such toner is removed from the photoconductor by the fur brush 14 and the blade 15. Cleaning may be performed only with a cleaning brush,
As the cleaning brush, a known brush such as a fur brush or a mag fur brush is used.

When a positive (negative) charge is applied to the electrophotographic photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with toner of negative (positive) polarity (electrostatic detection fine particles), a positive image can be obtained, and if it is developed with toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to such a developing unit.
In addition, a known method is used for the charge removing means.

FIG. 5 shows another example of the electrophotographic process according to the present invention. The photoreceptor 21 has a photosensitive layer formed by using the dispersion prepared by the above-described method, is driven by the drive rollers 22a and 22b, is charged by the charger 23, is exposed by the light source 24, and is exposed to light (development). Not shown),
Transfer using the charger 25, exposure before cleaning by the light source 26, cleaning by the brush 27, and static elimination by the light source 28 are repeatedly performed. In FIG. 5, the photosensitive member 2
1 (of course, in this case, the support is translucent), light irradiation for pre-cleaning exposure is performed from the support side.

The above-described electrophotographic process is an example of the embodiment of the present invention, and other embodiments are of course possible. For example, in FIG. 5, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or the image exposure and the charge erasing exposure may be performed from the support side.

On the other hand, in the light irradiation step, image exposure, pre-cleaning exposure, and charge removal exposure are shown, but in addition, pre-transfer exposure, pre-exposure of image exposure, and other known light irradiation steps are provided. Light irradiation can also be performed on the body.

The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, or may be incorporated in the apparatus in the form of a process cartridge. The process cartridge includes a photoreceptor, and further includes a charging unit, an exposing unit, a developing unit, a transferring unit, a cleaning unit, and a discharging unit.
Devices (parts). Although there are many shapes and the like of the process cartridge, a general example is shown in FIG. The photoreceptor 16 has a photosensitive layer formed on a conductive support using a dispersion prepared by the method described above.

[0081]

The present invention will be described below with reference to examples.
The present invention is not limited by these embodiments. All parts are parts by weight.

First, a specific synthesis example of a crystalline (so-called Y-type) titanyl phthalocyanine pigment having a maximum diffraction peak at a Bragg angle of 2θ of 27.2 ° ± 0.2 ° will be described. (Pigment production example) 525 parts of fuclodinitrile and 4000 parts of 1-chloronaphthalene are stirred and mixed, and 190 parts of titanium tetrachloride are added dropwise under a nitrogen stream. After dropping, gradually add 20
The temperature was raised to 0 ° C, and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 190 ° C and 210 ° C. After the reaction,
The mixture was allowed to cool to 130 ° C. and was filtered while hot.
The powder was washed with chloronaphthalene until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried to obtain 422 parts of a crude titanyl phthalocyanine pigment. Sixty parts of the obtained crude titanyl phthalocyanine pigment subjected to the washing with hot water was treated with 96% sulfuric acid 1000 parts.
The mixture was stirred at 3 to 5 ° C, dissolved, and filtered. The resulting sulfuric acid solution was dropped into 35,000 parts of ice water while stirring,
The precipitated crystals were filtered, and then repeatedly washed with water until the washing liquid became neutral, to obtain a water paste of titanyl phthalocyanine pigment. 1,2-dichloroethane 1 was added to this water paste.
After adding 500 parts and stirring at room temperature for 2 hours, further adding 2500 parts of methanol, stirring and filtering. This was washed with methanol and dried to obtain 49 parts of a titanyl phthalocyanine pigment.

The X-ray diffraction spectrum of the titanyl phthalocyanine pigment obtained in the pigment production example was measured under the following conditions. X-ray tube Cu, voltage 40kV, current 20mA, scanning speed 1 ° / min, scanning range 3 ° -40 °
Time constant 2 seconds,

FIG. 8 shows an X-ray diffraction spectrum of the titanyl phthalocyanine pigment obtained in the pigment production example. It can be seen that the obtained titanyl phthalocyanine pigment has a crystal form in which the maximum peak of the Bragg angle 2θ is at least 27.2 ° ± 0.2 °. This pigment contained a large lump, and a relatively fine portion was taken out and the particle size was observed by SEM. As a result, many particles of about 1 to 2 mm were contained.

(Example 1) The pigment obtained in the pigment production example was coarsely pulverized by a commercially available mixer. All lumps were gone and a relatively uniform powder was obtained. When the particle size was measured by SEM, all the particles were 1 mm or less.
Using this powder, a dispersion was prepared under the following conditions. As the dispersion pot, a glass ball mill pot having a diameter of 9 cm was used. This is referred to as Dispersion 1. Dispersion media: PSZ ball having a diameter of 2 mm 600 parts The above-mentioned pigment 2 parts Butyral resin 1.3 parts n-butyl acetate 108 parts The butyral resin is previously stored in a separate container in n-acetic acid.
The one dissolved in butyl was used. This is 70
r. p. m. For 4 hours.

Example 2 The pigment prepared in Example 1 (which was coarsely pulverized by a mixer) had a mesh size of 0,1.
Screening was performed with a 5 mm stainless mesh.
When the particle size was measured by SEM, all the particles were 0.5 mm or less. Using the pigment thus obtained, a dispersion was prepared in exactly the same manner and under the same conditions as in Example 1. This is referred to as dispersion liquid 2.

Example 3 The pigment prepared in Example 1 (which was coarsely pulverized by a mixer) had a mesh size of 0.1%.
Screening was performed using a 25 mm stainless mesh. When the particle size was measured by SEM, all the particles were 0.25 mm or less. Using the pigment thus obtained, a dispersion was prepared in exactly the same manner and under the same conditions as in Example 1. This is referred to as dispersion liquid 3.

Example 4 Using the pigment prepared in Example 3 (sieved with a stainless steel mesh of 0.25 mm), a dispersion was prepared under the following conditions. This is referred to as dispersion liquid 4. Dispersion media: zirconia ball having a diameter of 0.5 mm 37 parts of the above pigment 25 parts of butyral resin 25 parts of 2-butanone 500 parts of butyral resin was previously dissolved in 2-butanone in another container. Rotor rotation speed 3000r with a commercially available bead mill disperser. p. m. For 10 minutes.

Example 5 The pigment prepared in Example 1 (which was coarsely pulverized by a mixer) had a mesh size of 0.1%.
Screening was performed with a 1 mm stainless mesh.
When the particle size was measured by SEM, all the particles were 0.1 mm or less. Using the pigment thus obtained, a dispersion was prepared in exactly the same manner and under the same conditions as in Example 4. This is referred to as dispersion liquid 5.

(Comparative Example 1) The same method as in Example 1 was used except that the pigment prepared in the Pigment Production Example (before the coarse pulverization of the mixer) was used.
A dispersion was prepared under the conditions. The dispersion time here is 4 hours. This is referred to as dispersion liquid 6.

(Comparative Example 2) A dispersion was prepared using the pigment prepared in the Pigment Production Example (before mixer coarse pulverization) under the same method and conditions as in Example 1 except for the dispersion time. The dispersion time is 24 hours. This is referred to as dispersion 7.

Comparative Example 3 Using the pigment prepared in Example 2 (which had been sieved with a 0.5 mm stainless mesh), a dispersion was prepared in the same manner and under the same conditions as in Example 4. This is referred to as dispersion liquid 8.

The particle size distribution of the pigments in the dispersions 1 to 8 prepared in Examples 1 to 5 and Comparative Examples 1 to 3 was
(Horiba, Ltd.). All the dispersions were dried, and the powder was measured for X-ray diffraction spectrum under the above conditions. Table 1 shows the results. From Table 1, it can be seen that the dispersions 1 to 5 have a small average particle size and do not change in crystal form.

[0094]

[Table 1]

(Examples 6 to 10 and Comparative Examples 4 and 5) An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions were sequentially placed on an electroformed nickel belt. Coating and drying were performed to produce a laminated photoreceptor (undercoat layer: 4.0 μm, charge generation layer: 0.3 μm, charge transport layer: 25 μm). [Undercoat layer coating liquid] Titanium dioxide powder 15 parts Polyvinyl butyral 6 parts 2-butanone 150 parts [Charge generating layer coating liquid] The above dispersions 1 to 7 were used, respectively. [Charge transport layer coating solution] Polycarbonate 10 parts Charge transport material of the following structural formula 7 parts

Embedded image 80 parts of methylene chloride

FIG. 5 shows the electrophotographic photosensitive member thus constructed.
And the image exposure light source was a 780 nm semiconductor laser (image writing with a polygon mirror). Printing was continuously performed on 10,000 sheets, and image evaluation at that time was performed. Table 2 shows the results. From Table 2, Dispersions 1
It can be seen that the photoreceptor using No. 5 gives a good image even after repeated use.

[0097]

[Table 2]

(Examples 11 to 14 and Comparative Example 6) Anodizing treatment was performed on the surface of an aluminum cylinder, and then sealing treatment was performed. The following charge generation layer coating solution and charge transport layer coating solution were sequentially applied and dried to form a 0.2 μm-thick charge generation layer and a 20 μm-thick charge transport layer. A photoreceptor was produced. [Coating solution for charge generation layer] The above-mentioned dispersions 1 to 6 were used, respectively. [Coating solution for charge transport layer] 8 parts of charge transport material having the following structural formula

Embedded image Polycarbonate 10 parts Methylene chloride 80 parts

FIG. 6 shows the electrophotographic photoreceptor thus formed.
After mounting in the electrophotographic process cartridge shown in
It was mounted on an image forming apparatus. Using a 780 nm semiconductor laser (image writing by a polygon mirror) as an image exposure light source, a probe of a surface voltmeter was inserted so that the surface potential of the photoconductor immediately before development could be measured. 50 consecutive
00 sheets were printed, and the surface potentials of the image-exposed area and the image non-exposed area at that time were measured initially and after 5,000 sheets. Table 3 shows the results. Table 3 shows that the photoreceptors using the dispersions 1 to 5 maintain a stable surface potential even after repeated use.

[0100]

[Table 3]

(Example 15) A photoconductor was prepared in the same manner as in Example 6, except that the support in Example 6 was changed from an electroformed nickel belt to an aluminum cylinder.

Example 16 A photoconductor was prepared in the same manner as that of Example 15 except that the coating liquid for the charge transport layer in Example 15 was changed to the following composition. [Coating solution for charge transport layer] 10 parts of polymer charge transport material having the following structural formula

Embedded image 100 parts of methylene chloride

Example 17 A photoconductor was prepared in the same manner as that of Example 15 except that the coating liquid for the charge transport layer in Example 15 was changed to the following composition. [Coating solution for charge transport layer] 10 parts of polymer charge transport material having the following structural formula

Embedded image 100 parts of methylene chloride

Each of the electrophotographic photosensitive members of Examples 15 to 17 was mounted in the electrophotographic process shown in FIG. 4 (however, the image exposure source was an LD emitting at 780 nm), and 10,000 sheets were continuously printed. Was printed, and the image at that time was evaluated at the initial stage and after 10,000 copies. Further, a change (decrease amount) in the film thickness of the charge transport layer was measured. Table 4 shows the results. From Table 4, Example 1
It can be seen that the electrophotographic photosensitive members of Nos. 6 to 17 show particularly excellent wear resistance.

[0105]

[Table 4]

[0106]

According to the present invention, there is provided a method for preparing a dispersion liquid very efficiently in preparing a dispersion liquid without changing the crystal form. By using this, a dispersion having a small particle size can be provided while maintaining a specific crystal form. This dispersion is very useful as a dispersion for producing an electrophotographic photoreceptor, and can provide a photoreceptor having specific photoreceptor characteristics and having few coating film defects. This provides a photosensitive member having high abrasion resistance while maintaining specific characteristics (high sensitivity and stable surface potential even after repeated use). Further, there are provided a stable electrophotographic apparatus and a process cartridge for the electrophotographic apparatus which do not cause a decrease in chargeability and an increase in residual potential even when repeatedly used without losing high sensitivity.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an electrophotographic photosensitive member used in the present invention.

FIG. 2 is a schematic sectional view of another electrophotographic photosensitive member used in the present invention.

FIG. 3 is a schematic sectional view of still another electrophotographic photosensitive member used in the present invention.

FIG. 4 is a schematic diagram for explaining an electrophotographic process and an electrophotographic apparatus of the present invention.

FIG. 5 is a schematic view for explaining an electrophotographic process and an electrophotographic apparatus of the present invention.

FIG. 6 is a schematic diagram illustrating a typical electrophotographic apparatus of the present invention.

FIG. 7 is an X-ray diffraction spectrum of a titanyl phthalocyanine pigment obtained by a synthesis example of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 5/06 312 G03G 5/06 312 371 371

Claims (14)

[Claims] When preparing a dispersion by wet-dispersing a pigment using a solid dispersion medium, the pigment particles to be subjected to the wet dispersion do not include particles having a size equal to or more than の of the media diameter. And a size of the solid dispersion medium is 2 mm or less in diameter. 2. A half of the diameter of a medium used for wet dispersion.
2. The method for producing a dispersion according to claim 1, wherein the pigment containing no particles of the above size is dispersed by a dry method. 3. A half of the diameter of a medium used for wet dispersion.
The method for producing a dispersion according to claim 1, wherein the pigment containing no particles having the above sizes is classified by a sieve or the like, and the particle size is previously adjusted. 4. The method according to claim 1, wherein the disperser in the wet method is a bead mill. 5. The method for producing a dispersion according to claim 1, wherein the pigment is an organic pigment. 6. The method according to claim 5, wherein the organic pigment is a phthalocyanine pigment. 7. The method according to claim 6, wherein the phthalocyanine pigment is titanyl phthalocyanine. 8. The pigment in the wet dispersion is at least CuK.
2. A titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° ± 0.2 ° with respect to characteristic X-rays having a wavelength of 1.514 °.
8. The method for producing a dispersion according to any one of claims 1 to 7. 9. A photoreceptor having a photosensitive layer containing at least an organic pigment on a conductive support, wherein the photosensitive layer comprises:
Prior to dispersion by the wet method, an organic pigment coarsely ground to a size of 1/2 or less of the diameter of the solid dispersion medium used for the wet dispersion by a dry dispersion / pulverization means or a classification means such as a sieve is wet-dispersed. An electrophotographic photoreceptor, which is a photosensitive layer formed by applying and drying the obtained dispersion. 10. The electrophotographic photoconductor according to claim 9, wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer. 11. The electrophotographic photoreceptor according to claim 10, wherein the charge transporting layer contains a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain. 12. An electrophotographic photosensitive member comprising:
An electrophotographic method in which image exposure, development, transfer, cleaning, and static elimination are repeated, wherein the electrophotographic photosensitive member is used for wet dispersion by a classification means such as a dry dispersion / pulverization means or a sieve prior to the wet dispersion. A photosensitive layer formed by applying and drying a dispersion prepared by wet-dispersion using an organic pigment coarsely ground to a size equal to or less than 1/2 of the dispersion media diameter, and forming a photosensitive layer on a conductive support. An electrophotographic method characterized by being a photographic photoreceptor. 13. An electrophotographic apparatus comprising at least a charging unit, an image exposing unit, a developing unit, a transferring unit, a cleaning unit, a discharging unit and an electrophotographic photosensitive member,
The electrophotographic photoreceptor uses an organic pigment coarsely pulverized to a size equal to or less than half the diameter of a solid dispersion medium used for wet dispersion by a classification means such as a dry dispersion / pulverization means or a sieve prior to the wet dispersion. An electrophotographic apparatus comprising an electrophotographic photosensitive member having a photosensitive layer formed by applying and drying a dispersion prepared by wet dispersion on a conductive support. 14. A process cartridge for an electrophotographic apparatus comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is wet-typed by a dry dispersing / crushing means or a classifying means such as a sieve prior to the wet dispersion. A photosensitive layer formed by applying and drying a dispersion prepared by wet-dispersion using an organic pigment roughly pulverized to a size equal to or less than half the diameter of a solid dispersion medium used for dispersion is used as a conductive support. A process cartridge for an electrophotographic apparatus, wherein the process cartridge is an electrophotographic photosensitive member provided thereon.