JP7180973B2 - Electrophotographic photoreceptor and image forming apparatus provided with the same - Google Patents

Description

The present invention relates to an electrophotographic photoreceptor and an image forming apparatus having the same. More specifically, the present invention relates to a photosensitive layer composed of a substrate and at least a charge generation layer and a charge transport layer which are sequentially laminated on the substrate, or a photosensitive layer comprising a charge generation material and a charge transport material on the substrate. An electrophotographic photoreceptor comprising a single-layered photosensitive layer, wherein the charge-generating layer contains a specific crystal form of titanyl phthalocyanine as a charge-generating substance, and a copying machine having the same , an electrophotographic image forming apparatus such as a multifunction machine, a printer, and a facsimile machine.

2. Description of the Related Art Electrophotographic image forming apparatuses that form images using electrophotographic technology are widely used in copiers, printers, facsimile machines, and the like.
An electrophotographic photoreceptor (hereinafter also referred to as a "photoreceptor") used in an electrophotographic process is constructed by laminating a photosensitive layer containing a photoconductive material on a substrate.
At present, photoreceptors having a photosensitive layer mainly composed of an organic photoconductive material (also referred to as "organic photoreceptors") have been researched and developed, and currently occupy the mainstream of photoreceptors.

As an organic photoreceptor, a single-layer photoreceptor in which a charge-generating substance and a charge-transporting substance (also called "charge transfer substance") are dispersed in a binder resin (also called "binder resin" or "binder resin") is used. A structure in which layers are laminated on a substrate, and a laminated photosensitive layer ("function There has been proposed a configuration in which a "separate type") is laminated on a substrate. Among them, the function-separated type photoreceptor is widely used because of its excellent electrophotographic properties and durability, high degree of freedom in material selection, and ability to design various photoreceptor properties.

A phthalocyanine-based compound is given as a charge-generating substance used in an organic photoreceptor. It is known that phthalocyanine-based compounds not only have different sensitivity peaks and physical properties depending on the presence or absence of a central metal and their types, but also their physical properties change greatly depending on the difference in their crystal types (Non-Patent Document 1). Therefore, it is important to develop the photoreceptor including the examination of the crystal type.

Further, as a phthalocyanine compound used in an organic photoreceptor, there is an oxotitanyl phthalocyanine having a Y crystal type (Patent Documents 1 and 2).

JP-A-7-91486 Patent No. 2700859 Patent No. 3867121

Dyes and Chemicals, Vol. 24, No. 6 (1979)

Y-type oxotitanyl phthalocyanine is characterized by showing a maximum diffraction peak at a Bragg angle (2θ±0.2°) of 27.3° in its X-ray diffraction spectrum.
However, since water molecules contribute to sensitization in Y-type oxotitanyl phthalocyanine, although the sensitivity is good in a high-humidity environment, the sensitivity deteriorates in a low-humidity environment. Are known.

Also, in oxotitanyl phthalocyanine, β-type is known as a crystal form showing a diffraction peak at 26.2°. The β-type is known to have excellent environmental stability of sensitivity, but low sensitivity and poor repetitive stability.

In order to solve the above problems, hydroxygallium phthalocyanine, which has a small change in sensitivity to humidity, has been investigated, but the performance is still insufficient from the viewpoint of increasing sensitivity, and gallium, which is the central metal, is a rare metal. Therefore, there is a drawback that the cost is high.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electrophotographic photoreceptor and an image forming apparatus which are made of inexpensive materials, have excellent environmental stability and repetitive stability of sensitivity, and do not cause deterioration in sensitivity.

As a result of intensive studies to solve the above problems, the present inventors synthesized inexpensive titanium tetrachloride as a raw material, and obtained a Bragg angle (2θ±0.2°) of 9.0 in the X-ray diffraction spectrum. showing a maximum diffraction peak at 4° or 9.7° and showing diffraction peaks at least at 7.3°, 9.4°, 9.7°, 26.2° and 27.3°, and a diffraction peak By using oxotitanyl phthalocyanine, which has a peak intensity ratio of 26.2° and 27.3° within a specific range, as a charge-generating substance in an electrophotographic photoreceptor, the above problems have been solved and the present invention has been completed. .

However, the present invention provides a laminated photosensitive layer in which at least a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance are laminated in this order on a substrate, or a charge generation substance and a charge transport layer on a substrate. An electrophotographic photoreceptor comprising a single-layered photosensitive layer in which photosensitive layers containing a substance are laminated, wherein the charge-generating substance has a Bragg angle (2θ±0.2°) of 9.0 in the X-ray diffraction spectrum. showing a maximum diffraction peak at 4° or 9.7° and showing diffraction peaks at least at 7.3°, 9.4°, 9.7°, 26.2° and 27.3°, and 26.2° and 27.3° (26.2°/27.3°) is oxotitanyl phthalocyanine having a peak intensity ratio of 0.10 to 0.45.

The present invention also provides the above electrophotographic photosensitive composition, wherein the oxotitanyl phthalocyanine has an average particle size D (50%) of 0.15 μm to 0.35 μm in a dispersion coating liquid containing at least one binder resin and solvent. provide the body

The present invention also provides the electrophotographic photoreceptor, wherein the binder resin is a polyvinyl butyral resin having a total concentration of sulfate ions and chlorine (chloride) ions of 150 ppm or less.

Further, according to the present invention, the charge-transporting substance has the following formula (3):

で表わされるエナミン化合物である前記の電子写真感光体を提供する。

The electrophotographic photoreceptor is provided, which is an enamine compound represented by:

Further, the present invention provides an image forming apparatus comprising the above electrophotographic photoreceptor.

According to the present invention, by having a specific diffraction peak in the X-ray diffraction spectrum of oxotitanyl phthalocyanine synthesized using inexpensive titanium tetrachloride as a raw material, the sensitivity is excellent in environmental stability and repetition stability, and sensitivity deterioration is suppressed. It is possible to provide an electrophotographic photoreceptor and an image forming apparatus having the same.

1 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 1 described in Example 1. FIG. 2 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 2 described in Example 2. FIG. 3 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 3 described in Example 3. FIG. 4 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 4 described in Comparative Example 1. FIG. 4 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 5 described in Comparative Example 2. FIG. 4 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 6 described in Comparative Example 3. FIG. FIG. 7 is a cross-sectional view schematically showing an electrophotographic photoreceptor using the oxotitanyl phthalocyanine shown in FIGS. 1 to 6; FIG. 7 is a cross-sectional view schematically showing the general configuration of an image forming apparatus provided with the electrophotographic photoreceptor F using oxotitanyl phthalocyanine shown in FIGS. 1 to 6. FIG.

で示される。 BEST MODE FOR CARRYING OUT THE INVENTION Embodiments according to the present invention will be described below with reference to the drawings.
The oxotitanyl phthalocyanine used as the charge-generating substance in the present invention has the following formula (1):

is indicated by

The method for synthesizing oxotitanyl phthalocyanine may be any known method such as that described in Moser and Thomas, Phthalocyanine Compounds, Reinhold Publishing Corp., New York, 1963.
For example, dichlorotitanium phthalocyanine can be obtained in good yield by a method of melting o-phthalonitrile and titanium tetrachloride by heating or by heating in the presence of an organic solvent such as α-chloronaphthalene. Furthermore, by hydrolyzing this dichlorotitanium phthalocyanine with a base or water, oxotitanyl phthalocyanine can be obtained.

The obtained oxotitanyl phthalocyanine may contain a phthalocyanine derivative in which a hydrogen atom on the benzene ring is substituted with a substituent such as chlorine, fluorine, a nitro group, a cyano group or a sulfone group. The crystalline form of the present invention is obtained by treating such an oxotitanyl phthalocyanine composition with a water-immiscible organic solvent such as dichloroethane in the presence of water. As a method of treating oxotitanyl phthalocyanine with a water-immiscible organic solvent in the presence of water, oxotitanyl phthalocyanine is swollen with water and treated with an organic solvent, or water is treated with an organic solvent without swelling treatment. Examples include, but are not limited to, a method of adding to a solvent and throwing the oxotitanyl phthalocyanine powder into the solvent.

As a method of swelling oxotitanyl phthalocyanine with water, for example, a method of dissolving oxotitanyl phthalocyanine in sulfuric acid and precipitating it in water to form a wet paste. In addition, a method of swelling oxotitanyl phthalocyanine with water using a stirring/dispersing device such as a homomixer, a paint mixer, a ball mill, or a sand mill to form a wet paste may be mentioned, but is limited to these methods. is not.

Alternatively, the crystal form of the present invention can be obtained by stirring the oxotitanyl phthalocyanine composition obtained by hydrolysis for a sufficient period of time or by milling with mechanical strain.

As an apparatus used for this treatment, in addition to a general stirring apparatus, a homomixer, a paint mixer, a disperser, an agitator, a ball mill, a sand mill, an attritor, an ultrasonic dispersing apparatus, or the like can be used. After treatment, it is filtered and washed with methanol, ethanol, water or the like to isolate it.
The oxotitanyl phthalocyanine thus obtained exhibits excellent properties as a charge generating material for electrophotographic photoreceptors.

In the present invention, other charge-generating materials may be used in combination with the oxotitanyl phthalocyanine. For example, such charge-generating materials include α-type, β-type, Y-type and amorphous oxotitanyl phthalocyanines different in crystal form from the oxotitanyl phthalocyanine of the present invention, other metal phthalocyanines such as gallium, monoazo azo pigments such as bisazo pigments and trisazo pigments, indigo pigments such as indigo and thioindigo, perylene pigments such as peryleneimide and perylene anhydride, polycyclic quinone pigments such as anthraquinone and pyrenequinone, oxotitanium Metal phthalocyanines such as phthalocyanines and phthalocyanine pigments such as metal-free phthalocyanines, organic photoconductive materials such as squarylium dyes, pyrylium salts, thiopyrylium salts, and triphenylmethane dyes, and inorganic photoconductive materials such as selenium and amorphous silicon and the like, and those having sensitivity in the exposure wavelength range can be appropriately selected and used.

Electrophotographic photoreceptor (hereinafter simply referred to as photoreceptor)
Next, electrophotographic photoreceptors F01 and F02 using the charge generating material of the present invention will be described below with reference to FIG.
FIG. 7 is an enlarged view schematically showing a partial cross-sectional view of the electrophotographic photoreceptors F01 and F02.
As shown in FIG. 7, the electrophotographic photoreceptor F01 is a laminated type, and the electrophotographic photoreceptor F02 is a single layer type photoreceptor.
The laminated electrophotographic photoreceptor F01 includes an undercoat layer F21 laminated on a substrate F1, a charge generation layer F22 (specifically, a charge-generating substance-containing layer), and a charge-transporting layer F23 (specifically, a charge-transporting substance-containing layer). layer) (see the left diagram in FIG. 7).

The single-layer electrophotographic photoreceptor F02 is composed of an undercoat layer F21 laminated on the substrate F1 and a single-layer photosensitive layer F24 containing a charge-generating substance and a charge-transporting substance (see the right figure in FIG. 7). ).

The charge-generating layer F22 laminated on the substrate F1 via the undercoat layer F21 contains the oxotitanyl phthalocyanine of the present invention as a charge-generating substance that generates charges. The charge-transporting layer F23 is laminated on the charge-generating layer F22 and contains a charge-transporting material that transports the charges generated in the charge-generating layer F22.

Next, the base F1 constituting the electrophotographic photoreceptors F01 and F02 and the layers laminated on the base F1 will be described below.

Substrate The substrate F1 (specifically, a conductive substrate) has a function as an electrode of the electrophotographic photoreceptor F01 and a function as a supporting member. The constituent material of the base F1 is not particularly limited as long as it is a material used in the relevant technical field.

Specifically, the constituent materials of the base F1 include, for example, conductive metal materials such as aluminum, aluminum alloys, copper, zinc, stainless steel, and titanium; polymers such as polyethylene terephthalate, polyamide, polyester, polyoxymethylene, and polystyrene; materials as well as non-conductive materials such as hard paper materials and glass.

When a non-conductive material such as glass is used as the substrate F1, a conductive film such as a metal foil is laminated on the surface of the support, a metal material, a conductive polymer, a conductive polymer, tin oxide, indium oxide, or the like. Examples include those obtained by vapor-depositing or coating a layer of a chemical compound.
Among these, aluminum alloys such as JIS3003 series, JIS5000 series and JIS6000 series are particularly preferable.

The shape of the base F1 can be exemplified by a cylindrical shape, the diameter of the cylindrical base F1 can be exemplified from about 10 to 300 mm, and the length of the base F1 can be exemplified from about 200 mm to 1000 mm.
The surface of the substrate F1 is subjected, if necessary, to anodized film treatment, surface treatment with chemicals, hot water, etc., coloring treatment, and irregular reflection treatment such as roughening the surface within a range that does not affect the image quality. may be

Undercoat layer The undercoat layer F21 is formed by, for example, dissolving or dispersing a resin material in an appropriate solvent to prepare an undercoat layer-forming coating liquid, and applying this undercoat layer-forming coating liquid to the surface of the substrate F1. , can be formed by removing the organic solvent by drying.
Examples of the resin material that can be used for the undercoat layer F21 include natural polymer materials such as polyamide resin, casein, gelatin, polyvinyl alcohol, and ethyl cellulose, and one or more of these can be used. can do.
Among these resin materials, polyamide resins are preferred, and polyamide resins containing alcohol-soluble nylon resins and piperazine compounds are particularly preferred.

Solvents for dissolving or dispersing the resin material that can be used for the undercoat layer F21 include, for example, water, alcohols such as methanol, ethanol and butanol; glymes such as methyl carbitol and butyl carbitol; chlorine-based solvents such as trichloroethane; acetone, dioxolane, etc.;
Among these solvents, for example, non-halogenated organic solvents can be preferably used in consideration of the global environment.

Further, the coating liquid for forming the undercoat layer may contain metal oxide particles. The metal oxide particles can easily adjust the volume resistance value of the undercoat layer, can further suppress the injection of charges into the charge generation layer F22 and the single-layer photosensitive layer F24, and can be used under various environments. can maintain the electrical properties of the electrophotographic photoreceptors F01 and F02.
Examples of materials that can be used for metal oxide particles include materials such as titanium oxide, aluminum oxide, aluminum hydroxide, and tin oxide.

The ratio (C/D) between the total weight C of the binder resin and the metal oxide particles and the weight D of the solvent in the undercoat layer-forming coating solution is preferably, for example, about 1/99 to 40/60. /98 to 30/70 is particularly preferable.
The ratio (E/F) between the weight E of the binder resin and the weight F of the metal oxide particles is, for example, preferably about 90/10 to 1/99, particularly preferably about 70/30 to 5/95. .

The temperature in the process of drying the coating film of the undercoat layer F21 is not particularly limited as long as it is a temperature at which the solvent used can be removed. ~130°C is particularly preferred.
If the temperature for drying the coating film of the undercoat layer is less than about 50°C, the drying time may become long. On the other hand, if the drying temperature of the coating film of the undercoat layer exceeds about 140° C., the electrical properties of the electrophotographic photoreceptors F01 and F02 may be deteriorated during repeated use, resulting in deterioration of the resulting image.
Such temperature conditions are common not only to the formation of the undercoat layer, but also to the formation of layers such as the charge generation layer F22, the charge transport layer F23 and the single layer type photosensitive layer F24, which will be described later, and other treatments.
The thickness of the undercoat layer F21 is not particularly limited, but is preferably about 0.01 μm to 20 μm, particularly preferably about 0.05 μm to 10 μm.

Charge-Generating Layer The charge-generating layer F22 generates charges by absorbing light irradiated by a light emitting device that emits light such as a light beam (specifically, a semiconductor laser) in an electrophotographic device such as an image forming device. It has a function to function as a carrier, and contains a charge generation substance as a main component and, if necessary, a binder resin and an additive.

As the charge-generating substance, the oxotitanyl phthalocyanine of the present invention is used, and the other charge-generating materials described above may be contained. Therefore, the content of the oxophthalocyanine of the present invention is preferably as high as possible, and the content is preferably 80% or more.

The charge generation layer F22 can contain a binder resin for the purpose of improving the binding property. As the binder resin that can be used in the charge generation layer F22, resins having binding properties used in the relevant technical field and binder resins exemplified for the undercoat layer can be used. Those having excellent solubility are preferred.

Specifically, examples of binder resins that can be used in the charge generation layer F22 include polyester, polystyrene, polyurethane, phenol resin, alkyd resin, melamine resin, epoxy resin, silicone resin, acrylic resin, methacrylic resin, polycarbonate, poly Examples include arylate, phenoxy resin, polyvinyl butyral (PVB), polyvinyl formal, and copolymer resins containing two or more repeating units constituting these resins. Examples of copolymer resins include insulating resins such as vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, and acrylonitrile-styrene copolymer resins. can.

Binder resins that can be used in the charge generation layer F22 are not limited to these, and resins commonly used in the relevant technical field can be used as binder resins. These binder resins can be used individually by 1 type or in combination of 2 or more types.

Solvents that can be used in the coating liquid for forming the charge generation layer F22 include, for example, halogenated hydrocarbons such as dichloromethane and dichloroethane; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; Ethers such as tetrahydrofuran (THF) and dioxane; Alkyl ethers of ethylene glycol such as 1,2-dimethoxyethane; Aromatic hydrocarbons such as benzene, toluene and xylene; N,N-dimethylformamide, N,N- Examples include aprotic polar solvents such as dimethylacetamide.
Among these solvents, for example, non-halogenated organic solvents can be preferably used in consideration of the global environment. These solvents can be used individually by 1 type or in combination of 2 or more types.

Dispersers such as paint shakers, ball mills and sand mills can be used to dissolve or disperse the charge-generating substance in the binder resin solution. At this time, it is preferable to appropriately set the dispersion conditions so that impurities are not mixed into the coating liquid due to abrasion of the members constituting the container and the dispersing machine.
Other steps and their conditions are the same as those for forming the undercoat layer, and the description thereof is omitted here.
The thickness of the charge generation layer F22 is not particularly limited, but is preferably about 0.05 μm to 5 μm, more preferably about 0.1 μm to 1 μm.

Charge transport layer The charge transport layer F23 has a function of receiving charges generated by the charge generating material and transporting them to the surface Fa of the electrophotographic photoreceptor F01, and contains a charge transport material, a binder resin, and additives as necessary. You may As the charge transport substance, compounds used in the technical field can be used.

Specific examples of charge transport materials include carbazole derivatives, pyrene derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, Styryl compounds, hydrazone compounds, polycyclic aromatic compounds, indole derivatives, pyrazoline derivatives, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, triarylmethane derivatives , phenylenediamine derivatives, stilbene derivatives, enamine derivatives, benzidine derivatives, polymers having groups derived from these compounds in the main chain or side chain (poly-N-vinylcarbazole, poly-1-vinylpyrene, ethylcarbazole-formaldehyde resin , triphenylmethane polymer, poly-9-vinylanthracene, etc.), polysilane, and the like. These charge transport substances can be used singly or in combination of two or more.

As the binder resin that can be used in the charge transport layer F23, resins having binding properties that are used in the relevant technical field can be used, and resins that are excellent in compatibility with the charge transport material are preferable.
Specifically, binder resins that can be used in the charge transport layer F23 include, for example, vinyl polymer resins such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, copolymer resins thereof, polycarbonate, polyester, and polyester carbonate. , polysulfone, phenoxy, epoxy resins, silicone resins, polyarylates, polyamides, polyethers, polyurethanes, polyacrylamides, phenolic resins, polyphenylene oxides, and thermosetting resins obtained by partially cross-linking these resins. can be done. These binder resins can be used individually by 1 type or in combination of 2 or more types.

Among these, polystyrene, polycarbonate, polyarylate, and polyphenylene oxide are preferable because they have a volume resistance value of 10 ¹³ Ω or more, are excellent in electrical insulation, and are also excellent in film-forming properties, potential characteristics, and the like. , polycarbonates are particularly preferred.
The ratio A/B between the charge transport material and the binder resin is preferably about 10/12 to 10/30.

Examples of solvents that can be used in the coating liquid for forming the charge transport layer F23 include aromatic hydrocarbons such as benzene, toluene, xylene and monochlorobenzene; halogenated hydrocarbons such as dichloromethane and dichloroethane; THF (tetrahydrofuran) and dioxane. and ethers such as dimethoxymethyl ether; and aprotic polar solvents such as N,N-dimethylformamide. In addition, a solvent such as alcohols, acetonitrile or methyl ethyl ketone can be further added and used as necessary. Among these solvents, for example, non-halogenated organic solvents can be preferably used in consideration of the global environment. These solvents can be used individually by 1 type or in combination of 2 or more types.

Although the film thickness of the charge transport layer F23 is not particularly limited, it is preferably about 5 μm to 50 μm, more preferably about 10 μm to 40 μm.
Further, the coating liquid for forming the single-layer type photosensitive layer in the case of manufacturing the single-layer type electrophotographic photoreceptor F02 is prepared by mixing (dispersing) the aforementioned charge generation substance, charge transport substance, binder resin and solvent. can do.

Image Forming Apparatus Next, an image forming apparatus 700 equipped with the electrophotographic photoreceptor F01 or F02 using the oxotitanyl phthalocyanine of the present invention will be described below with reference to FIG. Note that the image forming apparatus 700 and its operation are not limited to the following items.

Configuration of Image Forming Apparatus FIG. 8 is a cross-sectional view schematically showing the schematic configuration of an image forming apparatus 700 equipped with an electrophotographic photoreceptor F using the oxotitanyl phthalocyanine of the present invention.

As shown in FIG. 8, the image forming apparatus 700 includes an electrophotographic photoreceptor F, charging means (specifically, a charger 710) for charging the surface Fa of the electrophotographic photoreceptor F, and the charger 710. Exposure means (specifically, exposure device 720) for exposing the electrophotographic photosensitive member F to form an electrostatic latent image, and developing the electrostatic latent image formed by the exposure device 720 to form a toner image. developing means (specifically, developing device 730); transferring means (specifically, transfer charger 740) for transferring the toner image formed by developing device 730 onto recording medium P such as recording paper; Cleaning means (specifically, cleaner device 750) for removing and collecting toner remaining on photoreceptor F, and fixing means for fixing the toner image transferred by transfer charger 740 onto recording medium P to form an image. (specifically, a fixing device 760). In this example, image forming apparatus 700 is illustrated as a monochrome printer (specifically, a laser printer).

Although the image forming apparatus 700 is a monochrome image forming apparatus in this example, it may be an intermediate transfer type color image forming apparatus capable of forming a color image. Specifically, a plurality of electrophotographic photoreceptors on which toner images are respectively formed, the same number as the types of ink, are arranged side by side in a predetermined direction (for example, the horizontal direction H or substantially the horizontal direction H), a so-called tandem type full color printer. It may be an image forming apparatus. Also, the image forming apparatus 700 may be another color image forming apparatus. Further, although the image forming apparatus 700 is a printer in this example, it may be, for example, a copier, a multifunction machine, or a facsimile machine.

The electrophotographic photosensitive member F is rotatably supported by a main body frame (not shown) of the image forming apparatus 700, and is rotated in a predetermined rotational direction R (clockwise in the figure) around the rotation axis α1 by a driving means (not shown). driven to rotate. The driving means includes, for example, an electric motor and a reduction gear, and transmits a rotational driving force to the base F1 of the electrophotographic photosensitive member F to rotationally drive the electrophotographic photosensitive member F at a predetermined peripheral speed. It has become.

Around the electrophotographic photosensitive member F, a charger 710, an exposure device 720, a developer 730, a transfer charger 740, and a cleaner device 750 are provided in this order from upstream to downstream in the rotational direction R. there is
The charger 710 is charging means for uniformly charging the surface Fa of the electrophotographic photosensitive member F to a predetermined potential by a high voltage applying means (specifically, a high voltage applying device 711). Examples of charging means include those of a non-contact charging system and those of a contact charging system. Examples of the non-contact charging method include a corona charging method using a charging charger, and examples of the contact charging method include a method using a charging roller or a charging brush. In this example, charger 710 includes a charging roller.

The exposure device 720 is exposure means for emitting light modulated based on image information. In this example, the exposure device 720 includes a light source (not shown) including, for example, a semiconductor laser or a light emitting diode (LED: Light Emitting Diode). By irradiating the surface Fa of the electrophotographic photosensitive member F in between, an electrostatic latent image corresponding to the image information is formed on the uniformly charged surface Fa of the electrophotographic photosensitive member F. FIG. The exposure device 720 repeatedly scans the surface Fa of the rotationally driven electrophotographic photosensitive member F with light modulated based on image information in the direction of the rotational axis α1 of the electrophotographic photosensitive member F, which is the main scanning direction. Thereby, an electrostatic latent image can be formed on the surface Fa of the electrophotographic photosensitive member F. As shown in FIG.

The developing device 730 contains a developer D (for example, toner and carrier for a two-component developer, or toner for a one-component developer), and an electrostatic latent image formed on the surface Fa of the electrophotographic photosensitive member F by the exposure device 720. is developed with a developer D. In this example, the developing device 730 includes a developing roller 730a provided to face the surface Fa of the electrophotographic photoreceptor F and supplying the developer D to the surface Fa of the electrophotographic photoreceptor F, and containing the developer D. and a developer tank 730b (specifically, a casing). The developing tank 730b supports the developing roller 730a so as to be rotatable about a rotational axis α2 parallel or substantially parallel to the rotational axis α1 of the electrophotographic photosensitive member F. As shown in FIG.

The transfer charger 740 transfers the toner image, which is a visible image, formed on the surface Fa of the electrophotographic photosensitive member F by the developing device 730 to the recording medium P which is conveyed in a predetermined conveying direction W by conveying means (not shown). It is a transfer means for transferring on. The transfer means applies a predetermined high voltage to the transfer nip portion TN formed between the electrophotographic photosensitive member F and the transfer charger 740 by means of a high voltage application means 741 (specifically, a high voltage application device). . The transfer means can be configured in the same manner as the charging means described above, and in this example, is a contact type transfer means for transferring the toner image onto the recording medium P by applying an electric charge of a polarity opposite to that of the toner to the recording medium P. It is said that

The cleaner device 750 is cleaning means for removing and collecting toner remaining on the surface Fa of the electrophotographic photosensitive member F after the transfer operation by the transfer charger 740 . In this example, the cleaner device 750 includes a cleaning blade 750a for removing toner remaining on the surface Fa of the electrophotographic photosensitive member F, and a recovery casing 750b for containing the toner removed by the cleaning blade 750a. Further, the cleaner device 750 is provided together with a static elimination means (specifically, a static elimination lamp) not shown.

The fixing device 760 is fixing means for fixing the toner image transferred onto the recording medium P by the transfer charger 740 . The fixing device 760 is provided downstream of the transfer nip portion TN between the electrophotographic photosensitive member F and the transfer charger 740 in the transport direction W. As shown in FIG. In this example, the fixing device 760 includes heating means (specifically, a heating roller 760a) and pressure means (specifically, a pressure roller 760b) provided facing the heating roller 760a. The pressure roller 760b is pressed against the heat roller 760a to form a fixing nip portion FN.
The image forming apparatus 700 also includes separating means (specifically, a separation claw 770) for separating the recording medium P from the electrophotographic photosensitive member F, and a housing (specifically, a Typically, it is provided in the casing 780).

Operation of Image Forming Apparatus In the image forming apparatus 700 described above, first, when the electrophotographic photosensitive member F is rotationally driven in a predetermined rotational direction R by the driving means, the charger 710 causes the surface Fa of the electrophotographic photosensitive member F to move. is uniformly charged to a predetermined potential.
Next, the surface Fa of the uniformly charged electrophotographic photosensitive member F is irradiated with light corresponding to image information from the exposure device 720 . An electrostatic latent image is formed on the surface Fa of the electrophotographic photosensitive member F by irradiation with light from the exposure device 720 .

The electrostatic latent image formed on the surface Fa of the electrophotographic photosensitive member F is developed by the developing device 730 to form a toner image on the surface Fa of the electrophotographic photosensitive member F. FIG.
The recording medium P sent in the conveying direction W from the upstream side of the electrophotographic photosensitive member F is transferred to the electrophotographic photosensitive member F in synchronism with the toner image formed on the surface Fa of the electrophotographic photosensitive member F. It is supplied to the transfer nip portion TN between the charger 740 and the charger 740 .
The toner image on the surface Fa of the electrophotographic photosensitive member F is given a charge having a polarity opposite to that of the toner image by the transfer charger 740 via the recording medium P supplied to the transfer nip portion TN. It is transferred onto the recording medium P.

The recording medium P to which the toner image has been transferred is further conveyed to the fixing device 760, and the toner image is heated and heated when passing through the fixing nip portion FN between the heating roller 760a and the pressure roller 760b of the fixing device 760. It is pressed and further discharged to the outside of the image forming apparatus 700 .
On the other hand, the toner remaining on the surface Fa of the electrophotographic photosensitive member F after the transfer of the toner image by the transfer charger 740 is removed from the surface Fa of the electrophotographic photosensitive member F by the cleaning device 750 and transferred to the toner collecting casing 750b. be recovered.
When images are to be continuously formed on a plurality of recording media P, the series of operations described above are repeated.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.
In Examples 1 to 9 and Comparative Examples 1 to 3, the oxotitanyl phthalocyanine described in Production Examples 1 to 6 was used as a charge generation substance, and a coating solution for forming an undercoat layer and a charge generation layer were formed on the substrate F1. and a coating solution for forming a charge transport layer are applied in this order to form an undercoat layer, a charge generation layer F21 and a charge transport layer F22 on the substrate F1, F01 in FIG. 7, that is, the electrophotographic photoreceptor in FIG. F (hereinafter also simply referred to as photoreceptor F) was produced.

Synthesis of oxotitanyl phthalocyanine Production Example 1
40 g of o-phthalodinitrile, 18 g of titanium tetrachloride, and 500 ml of α-chloronaphthalene are heated and stirred at 200 to 250°C for 3 hours in a nitrogen atmosphere, allowed to cool to 100 to 130°C, filtered while hot, and heated to 100°C. The crude product of dichlorotitanium phthalocyanine was obtained by washing with 200 ml of diluted α-chloronaphthalene. This crude product was washed at room temperature with 200 ml of α-chloronaphthalene and then with 200 ml of methanol, and then suspended and washed in 500 ml of methanol for 1 hour. After the crude product obtained after filtration was dissolved in 100 ml of concentrated sulfuric acid with stirring, the insoluble matter was separated by filtration. The sulfuric acid solution was poured into 3000 ml of water, the precipitated crystals were collected by filtration, suspended and washed repeatedly in 500 ml of water until the pH reached 6 to 7, and then collected by filtration again. After treatment for 1 hour and washing with methanol, the crystals of Production Example 1 were obtained by drying.

X-ray diffraction was measured under the following conditions.
X-ray source CuKα=1.541 Å
Voltage 50kV
Current 300mA
Start angle 5.0deg.
Stop angle 30.0deg.
Step angle 0.02deg.
Measurement time 5deg./min.
Measurement method θ/2θ scan method

FIG. 1 shows the X-ray diffraction spectrum pattern of this crystal. In the X-ray diffraction spectrum, the maximum diffraction peak is shown at the Bragg angle (2θ ± 0.2°) of 9.4° or 9.7°, and at least 7.3°, 9.4°, 9.7°, 26 It showed diffraction peaks at 0.2° and 27.3°, and the peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) was 0.26.

Production example 2
Crystals of Production Example 2 were obtained in the same manner as in Production Example 1, except that the wet cake was treated with the solvent for 40 minutes.
FIG. 2 shows the X-ray diffraction spectrum pattern of this crystal. In the X-ray diffraction spectrum, the maximum diffraction peak is shown at the Bragg angle (2θ ± 0.2°) of 9.4° or 9.7°, and at least 7.3°, 9.4°, 9.7°, 26 It showed diffraction peaks at 0.2° and 27.3°, and the peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) was 0.10.

Production example 3
Crystals of Production Example 3 were obtained in the same manner as in Production Example 1, except that the solvent treatment time of the wet cake was changed to 1 hour and 30 minutes.
FIG. 3 shows the X-ray diffraction spectrum pattern of this crystal. In the X-ray diffraction spectrum, the maximum diffraction peak is shown at the Bragg angle (2θ ± 0.2°) of 9.4° or 9.7°, and at least 7.3°, 9.4°, 9.7°, 26 It showed diffraction peaks at 0.2° and 27.3°, and the peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) was 0.43.

Production example 4
After obtaining a dichlorotitanium phthalocyanine crude product in the same manner as in Production Example 1, this crude product was washed at room temperature with 200 ml of α-chloronaphthalene and then with 200 ml of methanol, and then suspended and washed in 500 ml of methanol for 1 hour. did The crude product obtained after filtration was repeatedly suspended and washed in 500 ml of water until the pH reached 6 to 7, and then dried to obtain crystals of Production Example 4.
FIG. 4 shows the X-ray diffraction spectrum pattern of this crystal. The X-ray diffraction spectrum shows a maximum diffraction peak at a Bragg angle (2θ±0.2°) of 27.3° and at least 7.3°, 9.4°, 9.7°, 26.2° and 27°. It showed a diffraction peak at 0.3°, and the peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) was 0.31.

Production example 5
Crystals of Production Example 5 were obtained in the same manner as in Production Example 1, except that the wet cake was treated with the solvent for 24 minutes.
FIG. 3 shows the X-ray diffraction spectrum pattern of this crystal. In the X-ray diffraction spectrum, the maximum diffraction peak is shown at the Bragg angle (2θ ± 0.2°) of 9.4° or 9.7°, and at least 7.3°, 9.4°, 9.7°, 26 It is an oxotitanyl phthalocyanine having diffraction peaks at .2° and 27.3° and a peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) of 0.04. rice field.

Production example 6
Crystals of Production Example 5 were obtained in the same manner as in Production Example 1, except that the wet cake was treated with the solvent for 2 hours.
FIG. 3 shows the X-ray diffraction spectrum pattern of this crystal. In the X-ray diffraction spectrum, the maximum diffraction peak is shown at the Bragg angle (2θ ± 0.2°) of 9.4° or 9.7°, and at least 7.3°, 9.4°, 9.7°, 26 It is an oxotitanyl phthalocyanine that exhibits diffraction peaks at .2° and 27.3° and has a peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) of 0.55. rice field.

Example 1
Coating liquid for forming undercoat layer 3 parts by weight of titanium oxide (manufactured by Showa Denko Co., Ltd., trade name: TS-043) and 2 parts by weight of copolyamide (nylon) (manufactured by Toray Industries, trade name: CM8000), methyl In addition to 25 parts by weight of alcohol, dispersion treatment was performed for 8 hours using a paint shaker (dispersing machine) to prepare 3 kg of a coating liquid for forming an undercoat layer. Next, the coating liquid was applied to the substrate by a dip coating method. Specifically, a coating tank was filled with the obtained coating liquid, and an aluminum drum-shaped substrate having a diameter of 30 mm and a length of 357 mm was immersed in the coating liquid as a conductive substrate, pulled up, and dried to a film thickness of 1.0 mm. An undercoat layer (intermediate layer) of 0 μm was formed.

Coating liquid for forming charge generation layer 1 part by weight of oxotitanyl phthalocyanine obtained in Production Example 1 and 1 part by weight of polyvinyl butyral (PVB) resin (manufactured by Sekisui Chemical Co., Ltd., trade name: BX-1) as a binder resin was added to 98 parts by weight of methyl ethyl ketone, and glass beads (AS ONE, trade name: BZ-1, bead diameter 1 mm) were used as media, and dispersion treatment was performed for 2 hours in a paint shaker to prepare 3 kg of a charge generation layer forming coating liquid. .
The average particle size D (50%) of oxotitanyl phthalocyanine in the resulting coating liquid for forming a charge generation layer was evaluated using a laser diffraction particle size distribution analyzer (manufactured by Nikkiso Co., Ltd., Microtrac MT-3000II). The average particle size D (50%) was 0.21 µm.

In addition, when the ionic impurity concentration of the polyvinyl butyral resin used as the binder resin was evaluated using an ion chromatography analyzer (manufactured by Thermo Fisher Scientific, ICS-1500, 2000), the total concentration of sulfate ions and chloride ions was It was 133 ppm.

Next, in the same manner as in the formation of the undercoat layer, the coating solution for forming the charge generation layer was applied to the surface of the undercoat layer by dip coating. That is, the obtained coating solution for forming the charge generation layer was filled in a coating bath, and the drum-shaped substrate having the undercoat layer formed thereon was immersed in the coating solution, pulled up, and air-dried to generate charges having a thickness of 0.2 μm. formed a layer.

Coating liquid for forming charge transport layer The following chemical formula (2) as a charge transport material:

で表されるトリフェニルアミン系化合物（ＴＰＤ）（東京化成工業株式会社製、商品名：Ｄ２４４８）２重量部、Ｚ型ポリカーボネート（帝人化成株式会社製、商品名：ＴＳ２０５０）３重量部、テトラヒドロフラン２４重量部を加え、電荷輸送層形成用塗布液３ｋｇを作製した。次に、浸漬塗布法にて電荷輸送層形成用の塗布液を電荷発生層表面に塗布した。すなわち、得られた電荷輸送層形成用の塗布液を塗布槽に満たし、電荷発生層の形成されたドラム状基体を塗布液に浸漬した後引きあげ、１３０℃で１時間乾燥して膜厚２８μｍの電荷輸送層を形成した。このようにして、図８に示す感光体Ｆを作製した。

Triphenylamine compound represented by (TPD) (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: D2448) 2 parts by weight, Z-type polycarbonate (manufactured by Teijin Chemicals Co., Ltd., trade name: TS2050) 3 parts by weight, tetrahydrofuran 24 Parts by weight were added to prepare 3 kg of a coating liquid for forming a charge transport layer. Next, a coating liquid for forming a charge transport layer was applied to the surface of the charge generation layer by dip coating. That is, the obtained coating solution for forming the charge transport layer was filled in a coating tank, and the drum-shaped substrate on which the charge generation layer was formed was immersed in the coating solution, pulled up, dried at 130° C. for 1 hour, and had a film thickness of 28 μm. A charge transport layer was formed. In this manner, a photoreceptor F shown in FIG. 8 was produced.

Example 2
A photoreceptor F was prepared in the same manner as in Example 1, except that the oxotitanyl phthalocyanine obtained in Production Example 2 was used in the charge generation layer forming coating liquid.

Example 3
Photoreceptor F was prepared in the same manner as in Example 1, except that the oxotitanyl phthalocyanine obtained in Production Example 3 was used in the charge generation layer forming coating liquid.

Example 4
Photosensitization was carried out in the same manner as in Example 1, except that the medium used in the charge generation layer forming coating solution was changed to glass beads (AS ONE, trade name: BZ-04, bead diameter 0.4 mm). Body F was created.
Here, the average particle diameter D (50%) of the obtained coating liquid for forming the charge generation layer was 0.15 μm.

Example 5
Photoreceptor F was prepared in the same manner as in Example 1, except that glass beads (AS ONE, trade name: BZ-2, bead diameter: 2 mm) were used as the medium in the coating liquid for forming the charge generation layer. was made.
Here, the average particle size D (50%) of the obtained coating liquid for forming the charge generation layer was 0.29 μm.

Example 6
Photosensitization was carried out in the same manner as in Example 1, except that the medium used in the charge generation layer forming coating solution was changed to glass beads (AS ONE, trade name: BZ-01, bead diameter 0.1 mm). Body F was created.
Here, the average particle size D (50%) of the obtained charge-forming coating liquid was 0.10 μm.

Example 7
Photoreceptor F was prepared in the same manner as in Example 1, except that glass beads (AS ONE, trade name: BZ-3, bead diameter: 3 mm) were used as media in the charge generation layer forming coating solution. was made.
Here, the average particle diameter D (50%) of the obtained coating liquid for forming the charge generation layer was 0.35 μm.

３で表されるエナミン系化合物を用いたことを除いて、実施例１と同様の方法で感光体Ｆを作製した。 Example 8
In the charge-transporting layer coating solution, the following chemical formula (3) as a charge-transporting substance:

Photoreceptor F was produced in the same manner as in Example 1, except that the enamine compound represented by 3 was used.

Comparative example 1
The same procedure as in Example 1 was performed except that the oxotitanyl phthalocyanine obtained in Production Example 4 and showing a maximum diffraction peak at 27.3° in the X-ray diffraction spectrum pattern was used in the charge generation layer forming coating liquid. Photoreceptor F was produced by the method.

Comparative example 2
In the coating liquid for forming the charge generation layer, the peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) in the X-ray diffraction spectrum pattern obtained in Production Example 5 was 0. Photoreceptor F was prepared in the same manner as in Example 1, except that oxotitanyl phthalocyanine having No. 04 was used.

Comparative example 3
In the coating liquid for forming the charge generation layer, the peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) in the X-ray diffraction spectrum pattern obtained in Production Example 6 was 0. Photoreceptor F was prepared in the same manner as in Example 1, except that oxotitanyl phthalocyanine having No. 55 was used.

Comparative example 4
Photoreceptor F was prepared in the same manner as in Example 1, except that another polyvinyl butyral resin (manufactured by Eastman Chemical Co., trade name: B-72) was used as the binder resin in the charge generation layer forming coating liquid. made.
Here, the total concentration of sulfate ions and chloride ions in the binder resin was 854 ppm.

Evaluation The sensitivity and environmental stability of the sensitivity of the photoreceptors F produced in Examples 1 to 9 and Comparative Examples 1 to 4 were evaluated as follows.
Photoreceptors F prepared in Examples 1 to 9 and Comparative Examples 1 to 4 were tested at low temperature/low humidity ( Under the L/L) environment, the halftone surface potential VH of the photosensitive member was measured. The surface potential VH represents the surface potential of the photoreceptor in the halftone portion during exposure.
VG: Very good (0≦|VH|<230).
G: Good (230≦|VH|<260).
NB: Fairly good (260≦|VH|<290).
B: Not good (290≦|VH|).

As an index of the environmental stability of sensitivity, a value ΔVH was calculated by subtracting the surface potential VH at low temperature/low humidity (L/L) from the surface potential VH under high temperature/high humidity (H/H) environment.
VG: Very good (0≤ΔVH<30).
G: Good (30≤ΔVH<60).
NB: Fairly good (60≦ΔVH<90).
B: Not good (90≦ΔVH).

Here, the surface potential VH is used as an evaluation index because the difference in the environmental stability of the sensitivity is more likely to occur than the photoreceptor surface potential VL of the solid black portion.

Next, the repeated fatigue stability of the photoreceptors F of Examples 1 to 9 and Comparative Examples 1 to 4 was evaluated as follows.
Using the above test copier, the photoreceptor F produced in Examples 1 to 9 and Comparative Examples 1 to 4 was subjected to 500,000 rotations from the initial charging potential (V0) under normal temperature/low humidity (N/L) environment. A value ΔV0 was calculated by subtracting the subsequent charging potential.
VG: Very good (0≤ΔV0<30).
G: Good (30≤ΔV0<60).
NB: Fairly good (60≦ΔV0<90).
B: Not good (90≤ΔV0).

Using the above test copier, the photoreceptors F produced in Examples 1 to 9 and Comparative Examples 1 to 4 under a high temperature/high humidity (H/H) environment had an initial surface potential (VL) of 500,000. A value ΔVL was calculated by subtracting the surface potential after rotation.
VG: Very good (0≤ΔVL<30).
G: Good (30≤ΔVL<60).
NB: Fairly good (60≦ΔVL<90).
B: Not good (90≤ΔVL).

Table 1 shows the above evaluation results.

As shown in Table 1, in Comparative Examples 1 and 2, ΔVH, which is an index of environmental stability of sensitivity, is 70 V and 95 V, respectively. In the X-ray diffraction spectrum, the maximum diffraction peak is shown at the Bragg angle (2θ ± 0.2°) of 9.4° or 9.7°, and at least 7.3°, 9.4°, 9.7°, 26 An oxo compound having diffraction peaks at 0.2° and 27.3° and a peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) of 0.10 to 0.45. Good results have been obtained using titanyl phthalocyanine.

In Comparative Example 3, although ΔVH, which is an index of environmental stability of sensitivity, was not significantly different from Examples 1 to 9, the peak intensity ratio of 26.2° and 27.3° in the X-ray diffraction spectrum ( 26.2°/27.3°) is as large as 0.55, it was found that sensitivity deterioration occurred due to β-transition, that is, change to β-type crystal form.

Further, from Examples 1 to 8, in the dispersion coating liquid comprising the oxotitanyl phthalocyanine of the present invention, at least one binder resin and solvent, the average particle diameter D (50%) of the oxotitanyl phthalocyanine was 0.15 μm. It has been found that good results can be obtained when the thickness is 0.35 μm or less.

In addition, from Examples 1 to 8 and Comparative Example 4, it was found that when the total concentration of sulfate ions and chloride ions contained in the polyvinyl acetal resin is 150 ppm or less, the increase in VL under high temperature/high humidity conditions can be further suppressed. understood.
Further, from Examples 1 and 9, it was found that better results were obtained by using the enamine compound represented by the chemical formula (3) as the charge-transporting substance.

From the evaluation results of the photoreceptors of Examples 1 to 8 and Comparative Examples 1 to 4 above, it was found that the charge generating substance had a Bragg angle (2θ±0.2°) of 9.4° or 9.7° in the X-ray diffraction spectrum. oxotitanyl phthalocyanine having a maximum diffraction peak at 26.2° and 27.3° (26.2°/27.3°) of 0.10 to 0.45; It was found that the electrophotographic photoreceptor, which is a polyvinyl butyral resin in which the total concentration of sulfate ions and chlorine (chloride) ions contained in the binder resin is 150 ppm or less, shows good results in all evaluations.

The present invention is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, this embodiment is merely an example in all respects and should not be construed in a restrictive manner. The scope of the present invention is indicated by the claims and is not restricted by the text of the specification. Furthermore, all modifications and changes within the equivalence range of claims are within the scope of the present invention.

According to the present invention, by using oxotitanyl phthalocyanine having a specific diffraction peak in the X-ray diffraction spectrum synthesized from cheap titanium tetrachloride as a charge-generating substance, excellent environmental stability and repetitive stability of sensitivity are obtained. It is possible to provide an electrophotographic photoreceptor that does not cause sensitivity deterioration and an image forming apparatus having the same.

700 Image forming apparatus F Electrophotographic photoreceptor F01 Electrophotographic photoreceptor F02 Electrophotographic photoreceptor F1 Substrate F21 Undercoat layer F22 Charge generation layer F23 Charge transport layer F24 Single layer type photoreceptor layer Fa Photoreceptor surface α1 Rotational axis α2 Rotational axis R Direction of rotation 710 Charger 711 High voltage application device 720 Exposure device 730 Developing device D Developer 730a Developing roller 730b Developing tank (casing)
740 transfer charger P recording medium W conveying direction of recording medium 741 high voltage applying means (high voltage applying device)
TN transfer nip portion 750 cleaner device 750a cleaning blade 750b toner recovery casing 760 fixing device 760a heating roller 760b pressure roller FN fixing nip portion 770 separation claw 780 casing (casing)
H Horizontal direction V Vertical direction

Claims (2)

A laminated photosensitive layer in which at least a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance are laminated in this order on a substrate, or a photosensitive layer containing a charge generation substance and a charge transport substance on a substrate. An electrophotographic photoreceptor composed of laminated single-layer photosensitive layers,
wherein the charge-generating substance exhibits a maximum diffraction peak at a Bragg angle (2θ±0.2°) of 9.4° or 9.7° in an X-ray diffraction spectrum and is at least 7.3°, 9.4°; In the peak intensity from the baseline of the X-ray diffraction spectrum at 9.7 °, 26.2 ° and 27.3 °, a diffraction peak with a peak intensity ratio of 9% or more to the maximum diffraction peak, 7.3 The peak intensity ratio of the diffraction peak at 26.2° and 27.3° to the maximum diffraction peak is 12% or more , and the peak intensity ratio between 26.2° and 27.3° (26.2°/27.3°) is 0.10 is an oxotitanyl phthalocyanine that is 0.45 from
The charge generation layer contains a binder resin, and the binder resin is a polyvinyl butyral resin having a total concentration of sulfate ions and chlorine (chloride) ions of 150 ppm or less,
The charge transport material has the following formula (3):

An electrophotographic photoreceptor characterized by being an enamine compound represented by: An image forming apparatus comprising the electrophotographic photoreceptor according to claim 1 .

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