JP2000330309A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high sensitivity, superior electrical characteristics and superior stability of electrification potential by forming a photosensitive layer containing two or more crystalline oxo-titanyl phthalocyanines chiefly containing microcrystals and exhibiting a specified X-ray diffraction spectrum as an electric charge generating material and at least one specified amine-hydrazone compound as an electric charge transferring material. SOLUTION: The electrophotographic photoreceptor has a photosensitive layer containing two or more crystalline oxo-titanyl phthalocyanines chiefly containing microcrystals and exhibiting a specified X-ray diffraction spectrum as an electric charge generating material and at least one amine-hydrazone compound of the formula as an electric charge transferring material. In the formula, R1-R5 are each lower alkyl, the residue of an aromatic hydrocarbon, the residue of a heterocyclic or aralkyl, R3 is H, halogen, lower alkyl, lower alkoxy, lower dialkylamino, trifluoromethyl or aralkyl and (n) is an integer of 1-3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor which uses an oxotitanyl phthalocyanine as a charge generating substance and an amine-human razone compound as a charge transporting substance, and has a high near-infrared wavelength range. The present invention relates to an electrophotographic photosensitive member having sensitivity.

[0002]

2. Description of the Related Art Electrophotographic photoconductors (hereinafter, also simply referred to as "photoconductors") currently in practical use are composed of an inorganic photoconductor using an inorganic photoconductive material having excellent sensitivity and durability and an organic photoconductor. Organic photoreceptors using photoconductive materials. A typical inorganic photoconductive material is Zn
There are O (zinc oxide) -based materials, Se (selenium) -based materials, CdS (cadmium sulfide) -based materials, and the like.

However, these inorganic photoconductive materials have been pointed out with various problems. In a ZnO-based material, the added sensitizer deteriorates its chargeability due to corona discharge or produces light brown upon exposure, so that stable image formation cannot be performed for a long period of time. Se-based materials are highly toxic, and crystallization easily progresses due to external factors such as temperature or humidity, and the chargeability is reduced and white spots are generated in images. Also, CdS-based materials cannot provide stable sensitivity in a humid environment.

On the other hand, an organic photoconductive material is generally easy to form a thin film by coating, has low manufacturing cost, and has high productivity. In addition, since there are many kinds of organic materials themselves, a photosensitive layer having low storage stability and low toxicity can be manufactured by appropriate selection, and can be easily discarded.
Further, the setting of the light absorption wavelength region can be easily changed, and the electrophotographic characteristics can be easily controlled by a combination of materials. Therefore, in recent years, further improvements in sensitivity and durability have been studied,
Organic materials are widely used.

A photoreceptor has a function-separated type in which a photosensitive layer having a laminated structure of a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance is formed on a conductive support. There is a single layer type in which a photosensitive layer containing a charge generating substance and a charge transporting substance is formed on a porous support. In the case of photoreceptors using organic materials, research and development have mainly been made on function-separated types.

As the charge transporting material, many materials having various molecular structures have been developed.
JP-A-59143 discloses a hydrazone system,
Japanese Patent Publication No. 98043 discloses a stilbene-styryl-based charge transporting substance, and Japanese Patent Publication No. 58-32373 discloses a triarylamine-based charge transporting substance. In addition,
Phenothiazine, triazole, quinoxaline,
Oxadiazole, oxazole, pyrazoline,
Triphenylmethane-based, dihydronicotinamide-based, indoline compounds, semicarbazone compounds and the like have been developed.

In recent years, an image forming apparatus such as a laser printer, which uses a laser light source instead of a white light source and achieves high speed, high image quality and non-impact, has been widely used. In particular, various methods using a semiconductor laser as a light source, which has remarkably progressed in recent years, have been attempted, and a photoconductor having high sensitivity to a long wavelength region of about 800 nm, which is a laser light wavelength band, is strongly desired.

As organic materials satisfying this requirement, for example, methine squaric acid dyes, indoline dyes,
Cyanine dyes, bilylium dyes, polyazo dyes,
There are phthalocyanine dyes and naphthoquinone dyes. However, methine squaric dyes, indoline dyes, cyanine dyes, and bilylium dyes can have longer wavelengths, but have low stability, particularly low repetition characteristics. Also, it is not easy to increase the wavelength of polyazo dyes,
And low productivity. Further, naphthoquinone dyes have low sensitivity.

On the other hand, phthalocyanine dyes have high sensitivity to long-wavelength light and are more stable than the above-mentioned dyes. Phthalocyanine-based compounds not only have different sensitivity peaks and physical properties depending on the presence or absence or type of central metal, but also have significant changes in physical properties depending on the crystal type thereof. "Dyes and Chemicals, Vol. 24, No. 6, p. .12
2, 1979, by Manabu Sawada. " Therefore, it is important to research and develop the photoreceptor including the examination of the crystal form of phthalocyanine.

A technique in which a phthalocyanine compound of a specific crystal type is selected for an electrophotographic photoreceptor has been reported. For example, JP-A-60-86551 discloses a metal-free phthalocyanine, and JP-A-63-133462 discloses a technique. Is a phthalocyanine containing aluminum;
No. 49544 describes examples using phthalocyanine using titanium as a central metal. Further, as the central metal of the phthalocyanine compound,
Many metals such as indium and gallium are known.

Among the phthalocyanine compounds, oxotitanyl phthalocyanine is particularly high in sensitivity, and "Electrographic Society of Japan, Vol. 32, No. 3, p. 282" describes a number of phthalocyanine compounds due to differences in diffraction angles of X-ray diffraction spectra. It is stated that it is classified into a crystal type. Further, as the crystal form of oxotitanyl phthalocyanine, α-type is disclosed in JP-A-61-217050 and JP-A-61-239248.
Japanese Patent Application Laid-Open No. Sho 62-67094 discloses an A type,
No. 366 and JP-A-63-198067 disclose the C-type, JP-A-63-20365 and JP-A-2-8.
No. 256, Japanese Unexamined Patent Publication No. 1-17066 and Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 65-65264 discloses an M type, Japanese Patent Application Laid-Open No. 3-54264 discloses an M-α type, Japanese Patent Application Laid-Open No. 3-128973 discloses an I-type, and Japanese Patent Application Laid-Open No. 62-67094 discloses an I-type and an II-type. Each is listed.

Crystals of oxotitanyl phthalocyanine whose lattice rule is known from structural analysis include C-type,
Phase I and Phase II. Pha
The type seII belongs to the triclinic system, and the phases I and C
The type belongs to the monoclinic system. When the crystal forms described in the above publication are analyzed from these known crystal lattice constants, A-type and I-type belong to Phase I-type, and α-type and B-type
It belongs to the case II type, and the M type belongs to the C type. Such an explanation is described, for example, in “J. of Imaging Science and Techn.
ology Vol. 37, No. 6, 1993, p. 605-p. 609 ".

JP-A-61-109056 discloses a photoconductor in which a charge transport layer containing a hydrazone compound and a binder resin is laminated on a charge generation layer containing an oxotitanyl phthalocyanine compound and a binder resin. Has been described.
Although this publication has sensitivity in a wavelength range of about 800 nm, it does not reach the sensitivity required for practically high image quality and high speed. As described above, oxotitanyl phthalocyanine is still low in sensitivity and inferior in potential stability against repeated use.

[0014]

As described above, phthalocyanine compounds, particularly oxotitanyl phthalocyanine, are useful as organic photoconductive materials having sensitivity in a long wavelength region. Although such oxotitanyl phthalocyanine has a plurality of crystal systems, in the X-ray diffraction spectrum, if the diffraction peaks in the triclinic system coincide with six diffraction peaks and in the monoclinic system four diffraction peaks coincide, the lattice constant is determined. Are the same, and the size and shape of the grid can be defined. Also, from the relative magnitude of the intensity of the diffraction peak,
The molecular arrangement in the crystal lattice of oxotitanyl phthalocyanine can be defined. Oxotitanyl phthalocyanine has such a difference in crystal type, and even in the same crystal lattice, due to a difference in molecular arrangement, chargeability,
Physical properties such as dark decay and sensitivity are different.

As described above, the function of oxotitanyl phthalocyanine as an organic photoconductive material depends on the crystal type and the molecular arrangement in the crystal lattice. Therefore, an electrophotographic photoreceptor using oxotitanyl phthalocyanine having a combination of a crystal type and a molecular arrangement capable of obtaining a high-performance organic photoconductive material is desired.

An object of the present invention is to provide high sensitivity to near-infrared light for semiconductor lasers, excellent electrical characteristics, little decrease in sensitivity even after repeated use, and excellent stability of charging potential. An object of the present invention is to provide an electrophotographic photosensitive member.

[0017]

According to the present invention, there is provided an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer mainly contains two or more types of crystal-type microcrystals as a charge generating substance. Containing oxotitanyl phthalocyanine,
The oxotitanyl phthalocyanine contains at least one amine-hydrazone compound represented by the following general formula (I) as a charge transport material, and the oxotitanyl phthalocyanine has a Bragg angle (2θ ± 0.2 °) of 7.3 in an X-ray diffraction spectrum. °, 24.
Diffraction peaks common to 1 ° and 27.2 ° are shown, and diffraction peaks having different Bragg angles are shown in the range of 9.0 ° to 10.0 °, respectively;
The intensity of each diffraction peak in the range of 0 ° is Bragg angle 2
The intensity of the diffraction peak having a Bragg angle of 27.2 ° is larger than the intensity of the diffraction peak at 7.2 ° and the Bragg angle is 7.3.
An electrophotographic photoreceptor characterized in that the intensity of each of the diffraction peaks at 0 ° and 24.1 ° is greater than the intensity of each diffraction peak.

[0018]

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[In the general formula (I), R ¹ , R ² , R ⁴ , R
⁵ may be the same or different and may have a lower alkyl group, an aromatic hydrocarbon residue which may have a substituent, a heterocyclic residue which may have a substituent, or a substituent. Represents an aralkyl group. R ³ represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower dialkylamino group, a trifluoromethyl group, or an aralkyl group which may have a substituent. n is an integer of 1 to 3. According to the present invention, the photosensitive layer formed on the conductive support exhibits a specific X-ray diffraction spectrum as described above.
It contains oxotitanyl phthalocyanine mainly containing fine crystals of more than one kind of crystal as a charge generating substance, and contains an amine-hydrazone compound represented by the general formula (I) as a charge transporting substance. The electrophotographic photoreceptor having such a photosensitive layer exhibits excellent photosensitivity and repetitive use characteristics as compared with a photoreceptor containing oxotitanyl phthalocyanine having one kind of crystal as a charge generating substance. It turns out. Further, in an electrophotographic apparatus using reversal development, the initial stability of the charging potential, particularly the first charging potential after dark adaptation, is excellent, and the change in the potential characteristics due to environmental changes, particularly, changes in temperature, and a slight It was found to be excellent in suppressing the occurrence of image defects. Therefore,
It can be suitably mounted on a high-sensitivity image forming apparatus such as a laser printer and a digital copier using a semiconductor laser light source.

Further, according to the present invention, the Bragg angle of 9.0 °
Each diffraction peak in the range of 10.0 ° is due to a microcrystal of a different crystal type, and has a Bragg angle of 9.4.
And 9.6 ° diffraction peaks.

According to the present invention, as the oxotitanyl phthalocyanine mainly containing the above-mentioned two or more crystal forms of microcrystals, each of the above-mentioned diffraction peaks is exhibited, and each of the above-mentioned diffraction peaks is different from each other. It was found that the one based on crystals was preferred. That is, an electrophotographic photoreceptor having such a photosensitive layer containing oxotitanyl phthalocyanine as a charge generating substance is compared with a photoreceptor containing oxo titanyl phthalocyanine having one type of crystal as a charge generating substance. hand,
It was found that they exhibited better light sensitivity characteristics and repeated use characteristics. Further, in an electrophotographic apparatus using reversal development,
It is superior in the initial stability of the charging potential, especially the potential of the first charge after dark adaptation, and is superior in suppressing changes in potential characteristics due to environmental changes, particularly changes in temperature, and suppressing the occurrence of microscopic image defects. understood. Therefore, it can be suitably mounted on a high-sensitivity image forming apparatus such as a laser printer and a digital copier using a semiconductor laser light source.

Further, in the present invention, the photosensitive layer has a laminated structure of a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, and the charge generating layer has a butyralization degree of 50 mol%. It is characterized by containing polyvinyl butyral in an amount of at least 70 mol% and oxotitanyl phthalocyanine mainly containing two or more types of crystallites.

According to the present invention, the photosensitive layer is of a so-called function-separated type and has a laminated structure of a charge generation layer and a charge transport layer. Since the charge generation layer further includes polyvinyl butyral having a butyralization degree in the above-described range, the charge generation layer can be easily formed into a layer as compared with a photoreceptor containing no polyvinyl butyral as described above. It can be.

In the present invention, the weight ratio of the polyvinyl butyral to oxotitanyl phthalocyanine is 1: 3.
１1: 1.

According to the present invention, it has been found that the weight ratio of polyvinyl butyral and oxotitanyl phthalocyanine contained in the charge generation layer is preferably in the above-mentioned range.

Further, in the present invention, the photosensitive layer has a laminated structure of a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, wherein the charge generating layer is a polymer of a vinyl compound or It is characterized by containing a copolymer of a vinyl compound and oxotitanyl phthalocyanine mainly containing two or more types of crystallites.

According to the present invention, the photosensitive layer is of a so-called function-separated type, and has a laminated structure of a charge generation layer and a charge transport layer. Further, since the charge generation layer further contains a vinyl compound polymer or a vinyl compound copolymer, the charge generation layer is compared with a photoreceptor not containing the vinyl compound polymer or the vinyl compound copolymer as described above. The generating layer can be easily formed into a layer.

The present invention is also characterized in that the weight ratio between the polymer of the vinyl compound or the copolymer of the vinyl compound and oxotitanyl phthalocyanine is 1: 2 to 1: 1.

According to the present invention, it has been found that the weight ratio of the polymer of the vinyl compound or the copolymer of the vinyl compound and the oxotitanyl phthalocyanine contained in the charge generation layer is preferably in the above-mentioned range.

Further, the present invention is characterized in that the amine-human razone compound of the general formula (I) is represented by the following general formula (II).

[0031]

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[In the general formula (II), R ¹ , R ² , R ⁴ , R ⁵
May be the same or different and may be a lower alkyl group, an aromatic hydrocarbon residue which may have a substituent, a heterocyclic residue which may have a substituent, or an aralkyl which may have a substituent. Represents a group. R ³ represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower dialkylamino group, a trifluoromethyl group, or an aralkyl group which may have a substituent. n is an integer of 1 to 3. According to the present invention, it has been found that the amine-hydrazone compound is preferably represented by the general formula (II) described above.

The present invention also relates to an amine of the general formula (II)
The human razone compound is characterized by being represented by the following general formula (III).

[0034]

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[In the general formula (III), Ar ¹ and Ar ² are
It may be the same or different and represents an aromatic hydrocarbon residue which may have a substituent or a heterocyclic residue which may have a substituent. R ³ represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower dialkylamino group, a trifluoromethyl group, or an aralkyl group which may have a substituent. R ⁴ and R ⁵ may be the same or different and each have a lower aralkyl group, an aromatic hydrocarbon residue optionally having a substituent, a heterocyclic residue optionally having a substituent or a substituent. Represents an aralkyl group which may be substituted. j, k, and n are integers of 1 to 3. According to the present invention, it has been found that the amine-hydrazone compound is more preferably one represented by the above general formula (III).

[0036]

FIG. 1 is a sectional view showing electrophotographic photosensitive members 8a to 8d according to an embodiment of the present invention. 1A is formed by forming a photosensitive layer 4 a on a conductive support 1. The photoconductor 8a includes a photosensitive layer 4a.
Is a so-called function-separated type photoconductor having a laminated structure of a charge generation layer 5 containing a charge generation substance 2 and a charge transport layer 6 containing a charge transport substance 3. In this embodiment, the charge generation layer 5 is disposed on the conductive support 1, and the charge generation layer 5
Although the charge transport layer 6 is disposed on the substrate, the charge generation layer 5 and the charge transport layer 6 may be disposed in reverse. FIG.
The photoreceptor 8b of (B) is substantially the same as the photoreceptor 8a, but includes an intermediate layer 7 disposed between the conductive support 1 and the photosensitive layer 4a.

The photosensitive member 8c shown in FIG. 1C is formed by forming a photosensitive layer 4b on the conductive support 1. Photoconductor 8c
Is a so-called single-layer type photoconductor in which the photosensitive layer 4b contains the charge generating substance 2 and the charge transporting substance 3. FIG.
The photoconductor 8d of (D) is substantially the same as the photoconductor 8c, but includes an intermediate layer 7 disposed between the conductive support 1 and the photosensitive layer 4b.

The photoconductors 8a to 8d (hereinafter collectively referred to as "photoconductor 8") are composed of photosensitive layers 4a and 4b (hereinafter, referred to as "photoconductor 8").
An overcoat layer (not shown) may be further arranged on the “photosensitive layer 4” when collectively referred to. The overcoat layer has a function of protecting the photosensitive layer 4.

The conductive support 1 is realized by a conductive metal material such as aluminum, aluminum alloy, stainless steel, copper, zinc, nickel and titanium. Also, for example, aluminum, a plastic film made of polyethylene and an insulating support surface such as paper,
The conductive support 1 may be realized by providing a conductive layer of gold, silver, copper, palladium, zinc, nickel, titanium, tin oxide, indium oxide, or the like. Such a conductive support 1 is realized in a shape such as a drum shape, a sheet shape, and a seamless belt shape.

The photosensitive layer 4 of the present invention contains oxotitanyl phthalocyanine described later as the charge generating substance 2 and contains an amine-hydrazone compound described later as the charge transporting substance 3.

The basic structure of oxotitanyl phthalocyanine is represented by the following general formula (IV).

[0042]

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In the general formula (IV), X represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent, and m is an integer of 0 to 4. Represent.

The oxotitanyl phthalocyanine used in the present invention mainly contains microcrystals of two or more crystal types. In the X-ray diffraction spectrum using CuKα ray,
Bragg angle (2θ ± 0.2 °) 7.3 °, 24.1 °,
It shows a common diffraction peak at 27.2 ° and a Bragg angle of 9.
Diffraction peaks having different Bragg angles are shown in the range of 0 ° to 10.0 °. The Bragg angle of 9.0 ° to 10.0
The intensity of each diffraction peak in the range of ° is the Bragg angle 27.
The intensity of the diffraction peak at a Bragg angle of 27.2 ° which is larger than the intensity of the diffraction peak at 2 ° is 7.3 ° at the Bragg angle,
It is larger than the intensity of each diffraction peak at 24.1 °. The Bragg angle is an angle 2θ of twice the angle θ formed between the surface of the microcrystal and the incident X-ray when X-rays are incident on the microcrystal and diffracted by satisfying the Bragg formula. This is an angle taking into account the error of °, and represents a so-called diffraction angle. In this specification, 9.0 ° to 10.0 ° means 9.0 ° or more and 10 ° or more.
Represents 0 ° or less.

Among the oxotitanyl phthalocyanines having the characteristics of the X-ray diffraction spectrum, those described in 9.
Diffraction peaks having different Bragg angles in the range of 0 ° to 10.0 ° are diffraction peaks due to microcrystals having different crystal types, and include diffraction peaks having Bragg angles of 9.4 ° and 9.6 °. Is particularly preferred.

The method for synthesizing oxotitanyl phthalocyanine is described in Mosa and Thomas, "Phthalocyanine Compounds".
(MOSER and Thomas. “Phthalocianine Compound
s ") or other known methods.

For example, dichlorotitanium phthalocyanine can be obtained in a high yield by heating and melting o-phthalonitrile and titanium tetrachloride or by heating in the presence of an organic solvent such as α-chloronaphthalene. Furthermore, oxotitanyl phthalocyanine is obtained by hydrolyzing dichlorotitanium phthalocyanine with a base or water. Also, oxotitanyl phthalocyanine can be obtained by heating 1,3-diiminoisoindoline and tetrabutoxytitanium with an organic solvent such as N-methylpyrrolidone. The oxotitanyl phthalocyanine obtained by these methods contains a phthalocyanine derivative in which the hydrogen atom of the benzene ring is substituted with any substituent such as chlorine, fluorine, nitro, cyano and sulfone. It doesn't matter.

The oxotitanyl phthalocyanine mainly containing two or more crystal forms of microcrystals used in the photoreceptor of the present invention can be obtained by converting the oxotitanyl phthalocyanine obtained as described above into water such as dichloroethane in the presence of water. Obtained by treatment with an immiscible organic solvent. As a method of treating with the organic solvent, a method of swelling the oxotitanyl phthalocyanine obtained as described above with water and treating with an organic solvent, and adding water to the organic solvent without performing the swelling treatment, Although a method in which the oxotitanyl phthalocyanine powder obtained as described above is charged therein may be mentioned, the present invention is not limited thereto. As the method of the swelling treatment, a method of dissolving the oxotitanyl phthalocyanine obtained as described above in sulfuric acid, precipitating in water to form a wet paste, and stirring / mixing such as a homomixer, a paint mixer, a ball mill, and a sand mill. A method of swelling the oxotitanyl phthalocyanine obtained as described above with water using a dispersing device with water to form a wet paste, and the like, are not limited to these methods.

The oxotitanyl phthalocyanine mainly containing two or more crystal forms of microcrystals used in the photoreceptor of the present invention is obtained by converting oxotitanyl phthalocyanine obtained by hydrolysis of dichlorotitanium phthalocyanine into a solution as described above. Alternatively, it can be obtained by stirring for a sufficient time in a solution in which a binder resin is dissolved, or by performing a milling treatment with a mechanical strain. As an apparatus used for such a treatment, in addition to a general stirring apparatus, a homomixer, a paint mixer, a disperser, an agitator, a ball mill, a sand mill, a paint shaker, a dyno mill, an attritor, an ultrasonic dispersion apparatus, and the like can be given. After the above-described processing, the oxotitanyl phthalocyanine used in the photoreceptor of the present invention is filtered, washed with methanol, ethanol, water, or the like, and isolated. After the treatment, a binder resin may be added and used as it is as a coating liquid. Also,
When a binder resin is added in advance during the treatment, it can be used as it is as a coating liquid.

The oxotitanyl phthalocyanine used for the photoreceptor of the present invention is not limited to those produced by the above-mentioned production method, but may be any method as long as it shows the above-mentioned X-ray diffraction spectrum specific to the present invention. It may be produced by

The thus obtained oxotitanyl phthalocyanine mainly containing two or more kinds of crystal-type microcrystals exhibits excellent characteristics as the charge generating substance 2 of the photoreceptor 8 of the present embodiment.

The charge generating layer 5 or the photosensitive layer 4b may contain, as the charge generating substance 2, a charge generating substance other than oxotitanyl phthalocyanine mainly containing two or more crystallites. For example, it may contain α-type, β-type, Y-type, and amorphous oxotitanyl phthalocyanine having different crystal types from oxotitanyl phthalocyanine used in the photoreceptor of the present invention. Further, other phthalocyanines, azo pigments, anthraquinone pigments, perylene pigments, polycyclic quinone pigments, squarium pigments and the like may be contained.

As described above, an oxotitanyl phthalocyanine specific to the present invention is produced, and a photosensitive layer containing the oxo titanyl phthalocyanine is prepared. Since oxotitanyl phthalocyanine exhibits high sensitivity even in a long wavelength range, a photoconductor having an optimum photosensitive wavelength range for an image forming apparatus using a light source in a long wavelength range, for example, a semiconductor laser or an LED (light emitting diode) as a light source, has been developed. can get. Further, the oxotitanyl phthalocyanine has a stable crystal form and is excellent in crystal stability against a solvent and heat. Therefore, a photoreceptor using this material exhibits excellent light sensitivity characteristics and repeated use characteristics. Excellent crystal stability is a great advantage not only in the production and properties of oxotitanyl phthalocyanine, but also in the production and use of photoreceptors.

The charge transport material contained in the photosensitive layer 4 of the present invention contains at least one amine-hydrazone compound represented by the following general formula (I).

[0055]

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Among the amine-hydrazone compounds represented by the above general formula (I), particularly, the following general formula (I)
The amine-hydrazone compound represented by I) is suitable from the viewpoint of synthesis cost.

[0057]

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In the above general formulas (I) and (II), R ¹ , R ² , R ⁴ and R ⁵ may be the same or different, and may be a lower alkyl group or an aromatic group which may have a substituent. Represents a hydrocarbon residue, a heterocyclic residue which may have a substituent, or an aralkyl group which may have a substituent. Examples of the lower alkyl group include a linear or branched alkyl group having 1 to 4 carbon atoms, and specifically, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl and t-butyl.
tert-butyl and the like. Examples of the aromatic hydrocarbon residue which may have a substituent include a phenyl group and 1-
And a naphthyl group. Examples of the heterocyclic residue which may have a substituent include a 1-pyridyl group.
Examples of the aralkyl group which may have a substituent include an alkyl group having a phenyl group at the terminal and having 1 to 3 carbon atoms, such as benzyl and phenethyl.

Examples of the substituent in the aromatic hydrocarbon residue, the heterocyclic residue and the aralkyl group include a lower alkyl group such as methyl and ethyl, a lower alkoxy group such as methoxy and ethoxy, methylamino, dimethylamino and ethyl. Examples thereof include amino groups such as amino, ethylmethylamino and diethylamino, and halogen atoms such as fluorine atom, chlorine atom and bromine atom, and preferably have one or two substituents.

R ³ represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower dialkylamino group, a trifluoromethyl group or an aralkyl group which may have a substituent. Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom. Examples of the lower alkyl group include the same lower alkyl groups as R ¹ , R ² , R ⁴ , and R ⁵ . Examples of the lower alkoxy group include a linear or branched alkoxy group having 1 to 4 carbon atoms, and specifically, methoxy, ethoxy, propoxy,
Isopropoxy, butoxy, sec-butoxy and t
ert-butoxy and the like. Examples of the lower dialkylamino group include an amino group substituted by a linear or branched alkyl group having 1 to 4 carbon atoms, and specific examples include dimethylamino, diethylamino, diisopropylamino, and dibutylamino. Can be Examples of the aralkyl group include the same lower aralkyl groups as those described above for R ¹ , R ² , R ⁴ , and R ⁵ .

Among the amine-hydrazone compounds represented by the above general formula (II), in particular, the following general formula (III)
The amine-hydrazone compound represented by is more preferable from the viewpoint of synthesis cost.

[0062]

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In the general formula (III), Ar ¹ and Ar ² may be the same or different, and may have an aromatic hydrocarbon residue which may have a substituent or a heterocyclic residue which may have a substituent. Represents a group. Examples of the aromatic hydrocarbon residue which may have a substituent include a phenyl group and 1-naphthyl group, and examples of the heterocyclic residue which may have a substituent include a 1-pyrezyl group. No. General formula (II
In I), R ^{3 to} R ⁵ represent the above-mentioned general formulas (I) and
Same as (II).

Table 1 shows specific examples of the amine-hydrazone compound.
, But is not limited thereto.

[0065]

[Table 1]

The charge transport layer 6 or the photosensitive layer 4b may contain one or more of the above-mentioned amine-hydrazone compounds as the charge transport material 3. Further, another charge transport material may be contained.

In the photosensitive layer 4 a of the function-separated type, the charge generation layer 5 preferably contains a binder resin in addition to the charge generation substance 2. As the binder resin, a butyralization degree of 5
0 mol% or more and less than 70 mol% of polyvinyl butyral,
Polymer of vinyl compound, for example, vinyl compound copolymer such as vinyl chloride-vinyl acetate copolymer, polyester, polyvinyl acetate, polyacrylate,
Polymethacrylate polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propiol, phenoxy resin, epoxy resin, urethane resin, cellulose ester, cellulose ether, nylon resin and copolymerized nylon resin, used alone or as a mixture of two or more types It doesn't matter.

The polyvinyl butyral used as the binder resin preferably has a degree of butyralization of not less than 50 mol% and less than 70 mol%. By using polyvinyl butyral having a butyralization degree in such a range,
The charge generation layer 5 can be easily formed into a layer as compared with the above-described photoreceptor in which the charge generation layer 5 does not contain polyvinyl butyral.

Further, as compared with the case where polyvinyl butyral having a butyralization degree of less than 50 mol% is used, a photosensitive member having higher sensitivity can be realized. This is presumably because, when polyvinyl butyral having a butyralization degree of less than 50 mol% is used, holes are not generated well, and satisfactory electrical characteristics cannot be obtained, resulting in insufficient sensitivity of the photoreceptor. Conversely, the residual potential is lower than when polyvinyl butyral having a butyralization degree of 70 mol% or more is used, and a photosensitive member excellent in forming a minute image can be realized. This is presumably because, when polyvinyl butyral having a degree of butyralization of 70 mol% or more is used, holes are successively trapped by repeated charging. For this reason, it is considered that the residual potential increases and fog occurs in the image.

The coating liquid for forming the charge generation layer 5 by a coating method contains a solvent in addition to the charge generation substance 2 and the binder resin. As the solvent, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate and acetic acid in consideration of the stability of the coating solution and the stability of the crystal form of oxotitanyl phthalocyanine used in the photoreceptor of the present invention. Esters such as butyl, ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as benzene, toluene and xylene, and aprotic polar solvents such as N, N-dimethylformamide and dimethyl sulfoxide, alone or in combination of two or more. It may be used.

The charge generation layer 5 is formed by, for example, a vapor deposition method such as a vacuum evaporation method, a sputtering method, and a CVD method. Further, the charge generating substance 2 and the binder resin are added to a solvent, and the mixture is pulverized and dispersed using a ball mill, a sand grinder, a paint shaker, an ultrasonic disperser, or the like to obtain a coating liquid. Using the coating liquid obtained in this manner, in the case of a sheet shape, by a coating method such as a baker applicator, a bar coater, casting and spin coating, and in the case of a drum shape, a spray method, a vertical ring method and immersion. The charge generation layer 5 may be formed by a coating method or the like. The thickness of the charge generation layer 5 is, for example, 0.05 μm.
m to 5 μm, preferably 0.08 μm to
It is selected in the range of 1 μm.

The proportion of oxotitanyl phthalocyanine mainly containing two or more kinds of crystallites used as the above-mentioned charge generation substance 2 in the charge generation layer 5 and the above-mentioned binder resin is determined by the type of each of the components. And the performance required for the electrophotographic photosensitive member.

For example, when the above-mentioned polyvinyl butyral is used as the binder resin, the weight ratio of the polyvinyl butyral to the oxotitanyl phthalocyanine is 1: 3 to 1:
1 is preferable, and 1: 2 to 1: 1 is particularly preferable.

When a vinyl compound polymer or a vinyl compound copolymer is used as the binder resin, the weight ratio of the vinyl compound copolymer or the vinyl compound copolymer to the oxotitanyl phthalocyanine is 1%. : 2
1: 1, preferably 2: 3 to 1: 1.

The charge transport layer 6 containing the above-mentioned amine-hydrazone compound as the charge transport substance 3 preferably further contains the above-mentioned binder resin. The mixing ratio of the amine-hydrazone compound as the charge transporting substance 3 and the binder resin in the charge transporting layer 6 is appropriately selected depending on the type of each component and the performance required for the electrophotographic photoreceptor. You. Usually, the binder resin and the amine-hydrazone compound are used in a weight ratio of about 1: 3 to 1: 2.

In such a function-separated type photosensitive layer 4a, the charge transport layer 6 may contain various additives such as a leveling agent, an antioxidant and a sensitizer, if necessary. As antioxidants, α-tocopherol, hydroquinone, hindered amine, hindered phenol,
Paraphenylenediamine, arylalkanes and their derivatives, organic sulfur compounds, organic phosphorus compounds, and the like may be used.

Further, the charge transport layer 6 is
Can be formed by a known method such as a method of dissolving or dispersing a substance to be contained in a solvent and applying the obtained coating liquid. For example, the charge transport material 3 is dissolved in a solvent,
A coating liquid is prepared by adding a binder resin. Using this coating liquid,
In the case of a sheet-shaped photoconductor, it is formed by a coating method such as a baker applicator, a bar coater, casting and spin coating, and in the case of a drum-shaped photoconductor, it is formed by a spray method, a vertical ring type, and a dip coating method. can do.

Examples of the solvent used in the coating solution for the charge transport layer include halogen solvents such as dichloromethane and 1,2-dichloroethane, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and esters such as ethyl acetate and butyl acetate. , Ethers such as tetrahydrofuran and dioxane, benzene,
Aromatic hydrocarbons such as toluene and xylene, N,
Aprotic polar solvents such as N-dimethylformamide and dimethyl sulfoxide can be used. These solvents may be used alone or in combination of two or more.

The thickness of the charge transport layer 6 is, for example, 10 μm
６０60 μm, preferably 10 μm-40
It is selected in the range of μm.

The single-layer type photosensitive layer 4b is formed by dispersing the charge generating substance 2 in the charge transport layer 6 described above. In this case, it is preferable that the particle size of oxotitanyl phthalocyanine, which is the charge generating substance 2, is sufficiently small.
Particle sizes below μm are preferred. If the amount of the charge generating substance 2 dispersed in the photosensitive layer 4b is too small, the sensitivity becomes insufficient, and if the amount is too large, the chargeability and the sensitivity are reduced. Therefore,
It is used in the range of 0.5% by weight to 50% by weight, preferably in the range of 1% by weight to 20% by weight, based on the total weight of the photosensitive layer 4b.

The thickness of the photosensitive layer 4b is, for example, 5 μm to 5 μm.
0 μm, preferably 10 μm to 40 μm
Is selected in the range.

A known plasticizer for improving the film forming property, flexibility and mechanical strength, an additive for suppressing the residual potential, and an additive for improving the dispersion stability of the photosensitive layer 4b. A dispersing aid, a leveling agent for improving applicability, a surfactant such as silicone oil or fluorine-based oil, an antioxidant and other additives may be added. As the antioxidant, the same antioxidant as in the case of the function separation type can be used.

The intermediate layer 7 is made of an aluminum anodic oxide film,
Implemented with inorganic layers such as aluminum oxide, aluminum hydroxide and titanium oxide. Also, copolymerized nylon,
It may be realized by an organic layer such as polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, and polyamide. Further, particles such as titanium oxide, tin oxide, and aluminum oxide may be dispersed therein. The thickness of the intermediate layer 7 is, for example, 0.5
μm to 3 μm, preferably 0.5 μm to
It is selected in the range of 1.5 μm.

The overcoat layer which may be provided on the photosensitive layers 4a and 4b can be realized by a conventionally known layer mainly composed of, for example, a thermoplastic resin or a thermosetting resin.

The present invention will be specifically described below with reference to Production Examples and Examples, but the present invention is not limited to the following Production Examples and Examples as long as the gist is not exceeded.

(Production Example 1) o-Phthalodinitrile and titanium tetrachloride were reacted by heating and stirring at a temperature of 200 ° C. to 250 ° C. for 3 hours in α-chloronaphthalene under a nitrogen atmosphere.
After cooling to 00 ° C to 130 ° C, the mixture was filtered while hot, and the obtained solid was washed with α-chloronaphthalene heated to 100 ° C to obtain a crude dichlorotitanyl phthalocyanine product.
This crude product is washed with α-chloronaphthalene at room temperature, further washed with methanol, and further washed with methanol for 1 hour under hot suspension. This is filtered, and the obtained crude product is dissolved by stirring in concentrated sulfuric acid, and impurities contained in the crude product are collected by filtration.

The obtained filtrate is poured into water to precipitate crystals. The solid formed by the aggregation of the crystals thus precipitated is collected by filtration, and the solid is repeatedly subjected to hot washing in water until the pH becomes 6 to 7, and then filtered. The solid (wet cake) thus obtained is washed with dichloromethane, further washed with methanol, and then dried to obtain an oxo-form containing mainly two or more crystalline microcrystals used in the photoreceptor of the present invention. Titanyl phthalocyanine was obtained.

FIG. 2 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained as described above.
The horizontal axis in FIG. 2 shows the Bragg angle (2θ ± 0.2 °), and the vertical axis shows the X-ray intensity. The oxotitanyl phthalocyanine used for the photoreceptor of the present invention produced as described above has a diffraction pattern common to Bragg angles of 7.3 °, 24.1 ° and 27.2 ° in the X-ray diffraction spectrum of FIG. Indicates a peak. In addition, the Bragg angle is 9.0 ° to 10.0 °
In the range, diffraction peaks having different Bragg angles are shown. The intensity of each diffraction peak in the Bragg angle range of 9.0 ° to 10.0 ° is greater than the intensity of each diffraction peak in the Bragg angle range of 9.0 ° to 10.0 °. The intensity of the diffraction peak at 2 ° has a Bragg angle of 7.
It is larger than the intensity of each diffraction peak at 3 ° and 24.1 °. As described above, it is found that the oxotitanyl phthalocyanine of the present invention mainly contains two or more types of crystallites having diffraction peaks common to 7.3 °, 24.1 ° and 27.2 °.

The conditions for measuring the X-ray diffraction spectrum are as follows.

X-ray source CuKα = 1.54050 ° Voltage 30 kV to 40 kV Current 50 mA Start angle 5.0 deg. Stop angle 30.0 deg. Step angle 0.01 deg. To 0.02 deg. Measurement time 0.5 deg. /Min-2.0 deg. / Min Measurement method θ / 2θ Scan method (Comparative Production Example 1) A crude product of dichlorotitanyl phthalocyanine is obtained in the same manner as in Production Example 1 described above. The obtained crude product is washed with α-chloronaphthalene at room temperature, and further hot-washed in methanol for 1 hour. This was filtered, and the obtained crude product was repeatedly heated and washed in water until the pH reached 6 to 7, and then dried to obtain oxotitanyl phthalocyanine crystals.

FIG. 3 shows an X-ray diffraction spectrum of the oxotitanyl phthalocyanine crystal obtained as described above. The vertical and horizontal axes are the same as in FIG. From the X-ray diffraction spectrum of FIG. 3, the oxotitanyl phthalocyanine crystal obtained in Comparative Production Example 1 was found to have a Bragg angle (2θ ±
(0.2 °) It can be seen that the crystal is similar to the Y-type crystal described in Patent Publication No. 1950255 showing a maximum diffraction peak at 27.3 °.

(Production Example 2) Crystals of Y-type oxotitanyl phthalocyanine obtained in Comparative Production Example 1 above and methyl ethyl ketone were mixed, and glass beads having a diameter of 2 mm were obtained using the above-mentioned feint conditioner (manufactured by Red Level Co., Ltd.). After washing with methanol and drying, oxotitanyl phthalocyanine used in the present invention was obtained.

FIG. 4 shows an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained as described above.
The horizontal axis and the vertical axis are the same as in FIGS. The oxotitanyl phthalocyanine used for the photoreceptor of the present invention produced as described above has a diffraction pattern common to Bragg angles of 7.3 °, 24.1 ° and 27.2 ° in the X-ray diffraction spectrum of FIG. Indicates a peak. In the range of 9.0 ° to 10.0 ° of Bragg angle, diffraction peaks having different Bragg angles are shown. Bragg angle 9.0 ° -1
The intensity of each diffraction peak in the range of 0.0 ° is greater than the intensity of each diffraction peak in the range of 9.0 ° to 10.0 °, and the intensity of the diffraction peak at a Bragg angle of 27.2 °. Is greater than the intensity of each diffraction peak at the Bragg angles of 7.3 ° and 24.1 °. Thus, it can be seen that the oxotitanyl phthalocyanine of the present invention mainly contains two or more types of crystallites exhibiting diffraction peaks common to 7.3 °, 24.1 ° and 27.2 °.

(Comparative Production Example 2) A crude product of dichlorotitanyl phthalocyanine is obtained in the same manner as in Production Example 1 described above. The thus-obtained crude product is washed with α-chloronaphthalene at room temperature, washed with methanol, and further hot-washed in methanol for 1 hour. Filter this,
The crude product obtained by filtration was repeatedly hot-washed in water until the pH reached 6 to 7, then milled with 1.2-dimethoxyethane, and dried to obtain an oxotitanyl phthalocyanine crystal. .

FIG. 5 shows an X-ray diffraction spectrum of the oxotitanyl phthalocyanine crystal obtained as described above. The horizontal axis and the vertical axis are the same as those in FIG. FIG.
From the X-ray diffraction spectrum, the oxotitanyl phthalocyanine crystal obtained in Comparative Production Example 2 showed a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 °, and a Bragg angle of 7.3 °. 9.5 °, 9.7 °, 1
Patent Publication No. 270 having diffraction peaks at 1.7 °, 15.0 °, 18.0 °, 23.5 ° and 24.1 °.
It can be seen that the crystal is similar to the exemplary crystal described in JP 0859.

Example 1 On a conductive support 1 made of a polyester film on which aluminum was deposited, titanium oxide and copolymerized nylon (CM8000, manufactured by Toray Industries, Inc.) were mixed in a mixed solvent of methyl alcohol and dichloroethane. The dissolved coating liquid for an intermediate layer was applied and dried to form an intermediate layer 7 having a thickness of 1 μm.

Next, 1 part by weight of oxotitanyl phthalocyanine (charge generating substance 2) obtained in Production Example 1 and 1 part by weight of a polybutyral resin (binder resin) (Eslec BL-1 manufactured by Sekisui Chemical Co., Ltd.) : Butyralization degree of 63 ± 3 mol%) and 70 parts by weight of methyl ethyl ketone, and the mixture was dispersed with glass beads having a diameter of 2 mm by a paint conditioner (manufactured by Red Level Co., Ltd.) to obtain a coating for a charge generation layer. The liquid was applied on the intermediate layer 7 and dried to form a charge generation layer 5 having a thickness of 0.4 μm.

Further, an amine-hydrazone compound (Charge transporting substance 3) of Exemplified Compound 4 shown in Table 1 and a polycarbonate resin (binder resin) (PCZ, manufactured by Mitsubishi Gas Chemical Company, Inc.)
-200) in a weight ratio of 1: 1 to prepare a 15 wt% coating liquid for a charge transport layer using dichloromethane as a solvent, apply the coating liquid on the charge generation layer 5 and dry it. The charge transport layer 6 having a thickness of 20 μm was formed. As described above, a function-separated type photoconductor 8b including the intermediate layer 7 and the photosensitive layer 4a having the laminated structure of the charge generation layer 5 and the charge transport layer 6 was obtained.

(Examples 2 to 5) As the charge transport material 3,
Instead of the amine-hydrazone compound of Exemplified Compound 4,
A function-separated type photoconductor 8b was obtained in the same manner as in Example 1 except that the amine-hydrazone compounds of the exemplified compounds 3, 5, 10, and 16 were used.

Example 6 As the charge generating substance 2, 2 parts by weight of the oxotitanyl phthalocyanine obtained in Production Example 1 and 1 part by weight of a vinyl chloride-vinyl acetate copolymer resin (binder resin) (Nissin) Chemical company: Solvain A5) and 70
A part by weight of methyl ethyl ketone was mixed and dispersed by a paint shaker (manufactured by Asada Iron Works). A function-separated type photoconductor 8b was obtained in the same manner as in Example 1 except that the thus-obtained coating liquid for a charge generation layer was used for forming the charge generation layer 5.

Example 7 2 parts by weight of the oxotitanyl phthalocyanine obtained in Production Example 1 and 1 part by weight of a polybutyral resin (binder resin) (Eslec BL-1 manufactured by Sekisui Chemical Co., Ltd.) 70 parts by weight of methyl ethyl ketone were mixed and dispersed by the paint shaker. A function-separated type photoconductor 8b was obtained in the same manner as in Example 1 except that the thus-obtained coating liquid for a charge generation layer was used for forming the charge generation layer 5.

(Example 8) As the charge generating substance 2, the oxotitanyl phthalocyanine obtained in Production Example 2 was used instead of the oxotitanyl phthalocyanine obtained in Production Example 1 described above, and the other conditions were the same as in Example 1. Thus, a function-separated type photoconductor 8b was obtained.

(Example 9) 3 parts by weight of Production Example 1 described above
Oxotitanyl phthalocyanine (charge generating substance 2) obtained in 1 above and 1 part by weight of polybutyral resin (binder resin)
(Sekisui Chemical Co., Ltd .: ESLEC BL-1) and 70 parts by weight of methyl ethyl ketone were mixed and dispersed by a paint shaker. A function-separated type photoconductor 8b was obtained in the same manner as in Example 1, except that the obtained charge generation coating liquid was used for forming the charge generation layer 5.

(Example 10) 1 part by weight of oxotitanyl phthalocyanine (charge generating substance 2) obtained in Production Example 2 and 1 part by weight of a polybutyral resin (binder resin)
(Sekisui Chemical Co., Ltd .: ESLEC BL-1) and 70 parts by weight of methyl ethyl ketone were mixed and dispersed by the paint shaker. A function-separated type photoconductor 8b was obtained in the same manner as in Example 1 except that the thus-obtained coating liquid for a charge generation layer was used for forming the charge generation layer 5.

Example 11 An intermediate layer 7 was formed on a conductive support 1 in the same manner as in Example 1. Next, 1 part by weight of the oxotitanyl phthalocyanine obtained in Production Example 1 (charge generating substance 2) and 10 parts by weight of an amine-hydrazone compound of Example Compound 4 shown in Table 1 (charge transporting substance 3) and 10 parts by weight Polycarbonate resin (binder resin)
(Manufactured by Mitsubishi Gas Chemical Co., Ltd .: PCZ-200), and an 18 wt% coating solution was prepared using dichloromethane as a solvent.
Dispersion treatment was carried out together with glass beads having a diameter of 2 mm by the paint conditioner. The obtained coating liquid for a photosensitive layer was applied on the intermediate layer 7 and dried to form a photosensitive layer 4b having a thickness of 20 μm. As described above, the intermediate layer 7
And a photosensitive layer 4b containing the charge generating substance 2 and the charge transporting substance 3 to obtain a single-layer type photosensitive member 8d.

Comparative Example 1 In place of the oxotitanyl phthalocyanine used in Example 1, a crystal of oxotitanyl phthalocyanine having an X-ray diffraction spectrum pattern shown in FIG. 3 obtained in Comparative Production Example 1 was used. Except for the above, a function-separated type photoconductor was obtained in the same manner as in Example 1.

(Comparative Example 2) Instead of the oxotitanyl phthalocyanine used in Example 1, a crystal of oxotitanyl phthalocyanine having an X-ray diffraction spectrum pattern shown in FIG. 5 obtained in Comparative Production Example 2 was used. Otherwise in the same manner as in Example 1, a function-separated type photoconductor was obtained.

(Comparative Example 3) 2 parts by weight of oxotitanyl phthalocyanine (charge generating substance 2) obtained in Production Example 1 and 1 part by weight of a polybutyral resin (binder resin) (manufactured by Sekisui Chemical Co., Ltd .: Eslek BH) -S: butyralization degree of 70 mol% or more) and 70 parts by weight of methyl ethyl ketone were mixed and dispersed. Example 1 except that the thus obtained coating solution for a charge generation layer was used for forming a charge generation layer.
In the same manner as in the above, a function-separated type photoconductor was obtained.

Comparative Example 4 4 parts by weight of oxotitanyl phthalocyanine (charge generating substance 2) obtained in Production Example 2 and 1 part by weight of a polybutyral resin (binder resin) (manufactured by Sekisui Chemical Co., Ltd .: Eslec BL) -1) and 70 parts by weight of methyl ethyl ketone were mixed and dispersed. The coating liquid for a charge generation layer obtained in this manner was used for forming a charge generation layer, and in the same manner as in Example 1, except that a function-separated type photoreceptor was obtained.

Comparative Example 5 A function-separated type photoreceptor was obtained in the same manner as in Example 1, except that a compound represented by the following formula (V) was used as the charge transporting substance 6.

[0111]

Embedded image

The electrophotographic properties of the photoreceptors prepared in Examples 1 to 11 and Comparative Examples 1 to 5 were evaluated using an electrostatic recording paper test apparatus (EPA-8200, manufactured by Kawaguchi Electric Co., Ltd.) as follows. did. The measurement conditions for the function-separated type photoreceptor were as follows: applied voltage: -6 kV, static: No. 3, 780 nm monochromatic light (irradiation light: 2 μW
/ Cm ² ), the half-exposure amount E _1/2 (μJ / cm ² ) required to attenuate the potential from −500 V to −250 V.
And to measure the initial potential V ₀ (-V). The measurement conditions for the single-layer type photoreceptor are as follows: applied voltage: +6 kV, static:
No. 3, and the potential was increased by 780 nm monochromatic light (irradiation light: 10 μW / cm ² ) dispersed by an interference filter.
The half-life exposure amount E _1/2 (μJ / cm ² ) and the initial potential V ₀ (+ V) required to attenuate the voltage from 500 V to +250 V were measured.

A commercially available digital copying machine (AR5130, manufactured by Sharp Corporation) was modified to mount the photoconductors of Examples 1 to 11 and Comparative Examples 1 to 5 on the photoconductor drum, and the continuous emptying was performed 30,000 times. A durability test by copying was performed, and before and after the endurance test, a half-exposure amount E1 _{/ 2} was measured by using the electrostatic recording paper test apparatus. Further, an endurance test was performed by 30,000 continuous blank copies in a high-temperature, high-humidity environment (35 ° C., 85%), and the residual potential Vr was measured before and after that. Further, the image characteristics of a copy obtained by reversal development at a charging potential of -800 V under the high temperature and high humidity environment, that is, whether or not a defect was observed in a minute image were evaluated. Similarly, in a low-temperature and low-humidity environment (5 ° C., 20
%), That is, the measurement of the charge reduction (V) of the first rotation of the drum after dark adaptation was performed. Table 2 shows the results.

[0114]

[Table 2]

As shown in Table 2, in each of Examples 1 to 11, the amount of deterioration of the charging potential in the durability test was sufficiently small, and the initial sensitivity, ie, the half-exposure amount, was sufficiently high as compared with Comparative Examples 1 and 2. It can be seen that the sensitivity degradation after the test is small. Further, it can be seen that the rise in the residual potential after the durability test in a high-temperature and high-humidity environment is sufficiently smaller than in Comparative Examples 1 to 5.

Further, it can be seen that Examples 1 and 7 have better image characteristics than Comparative Example 3. In addition, it can be seen that in Example 8, the increase in the residual potential after the durability test under high temperature and high humidity was sufficiently small as compared with Comparative Example 4. Further, Examples 1 to
In No. 11, it can be seen that the decrease in the charge of the first rotation of the drum after dark adaptation in a low-temperature and low-humidity environment is smaller than in Comparative Examples 1 and 2. Further, it can be seen that Example 1 has a higher initial sensitivity (half-exposure amount) as compared with Comparative Example 5, and is excellent.

As described above, it was found that the electrophotographic photoreceptor of the present invention exhibited excellent light sensitivity characteristics and repetitive use characteristics. Further, in an electrophotographic apparatus using reversal development, the initial stability of the charging potential, particularly the first charging potential after dark adaptation, is excellent, and the change in the potential characteristics due to environmental changes, particularly, changes in temperature, and a slight It was found to be excellent in suppressing the occurrence of image defects.

This is because the photoreceptor of the present invention uses oxotitanyl phthalocyanine, which mainly contains two or more crystal forms of microcrystals, as the charge generating substance. This is presumed to be because crystal disorder during synthesis or crystal lattice disorder due to mechanical action in the dispersion step of coating liquid preparation is smaller than in the case where is used. This is because, in the X-ray diffraction spectrum of oxotitanyl phthalocyanine used in the photoreceptor of the present invention, among the diffraction peaks at each Bragg angle, the peaks other than the maximum diffraction peak having the maximum intensity can be obtained relatively sharply. I understand. That is, it is considered that the oxotitanyl phthalocyanine mainly contains microcrystals in which the long-range arrangement of molecules is good in order, in other words, the molecular arrangement is almost regular and the molecular arrangement is slightly different.

The photoreceptor using such an oxotitanyl phthalocyanine has a more stable crystal form compared to a photoreceptor using an oxo titanyl phthalocyanine which has a single crystal type as conventionally used. And the dispersion of the crystalline substance is stable. Furthermore, in an electrophotographic apparatus using a reversal phenomenon, the initial stability of the charged potential (especially the first charge after dark adaptation), the stability of the potential characteristics due to environmental changes, particularly temperature characteristics, and the suppression of the occurrence of minute image defects. Excellent.

Therefore, the electrophotographic photosensitive member of the present invention has
It is possible to design a process that can take a copy from the second time, has a small change in potential characteristics due to environmental changes, obtains a good copy without minute image defects, and has high sensitivity and high sensitivity. Therefore, it can be suitably used for photoconductors such as laser printers and digital copiers using a semiconductor laser beam as a light source, which has been remarkably developed recently.

[0121]

According to the first aspect of the present invention, the photosensitive layer formed on the conductive support is composed of two or more types of crystallites having a specific X-ray diffraction spectrum as described above. It mainly contains oxotitanyl phthalocyanine as a charge generating substance, and contains an amine-hydrazone compound represented by the general formula (I) as a charge transporting substance. The electrophotographic photoreceptor having such a photosensitive layer exhibits excellent photosensitivity and repetitive use characteristics as compared with a photoreceptor containing oxotitanyl phthalocyanine having one kind of crystal as a charge generating substance. It turns out. Further, in an electrophotographic apparatus using reversal development, the initial stability of the charging potential, particularly the first charging potential after dark adaptation, is excellent, and the change in the potential characteristics due to environmental changes, particularly, changes in temperature, and a slight It was found to be excellent in suppressing the occurrence of image defects. Therefore, it can be suitably mounted on a high-sensitivity image forming apparatus such as a laser printer and a digital copier using a semiconductor laser light source.

According to the second aspect of the present invention, as the oxotitanyl phthalocyanine mainly containing the two or more types of crystallites, the oxotitanyl phthalocyanine exhibits the above-mentioned respective diffraction peaks, and the respective diffraction peaks are different from each other. It has been found that those based on crystalline microcrystals are preferred. That is, an electrophotographic photoreceptor having such a photosensitive layer containing oxotitanyl phthalocyanine as a charge generating substance is compared with a photoreceptor containing oxo titanyl phthalocyanine having one type of crystal as a charge generating substance. As a result, it was found that they exhibited better photosensitivity characteristics and repeated use characteristics. Further, in an electrophotographic apparatus using reversal development, the charge potential, particularly the initial stability of the first charge potential after dark adaptation, is excellent in the initial stability, and the change in the potential characteristics due to environmental changes, particularly, changes in temperature, and slight It was found to be superior due to suppression of the occurrence of image defects. Therefore, it can be suitably mounted on a high-sensitivity image forming apparatus such as a laser printer and a digital copier using a semiconductor laser light source.

According to the third aspect of the present invention, the photosensitive layer is of a so-called function-separated type, and has a laminated structure of a charge generation layer and a charge transport layer. Since the charge generation layer further includes polyvinyl butyral having a butyralization degree in the above-described range, the charge generation layer can be easily formed into a layer as compared with a photoreceptor containing no polyvinyl butyral as described above. It can be.

According to the fourth aspect of the present invention, it has been found that the weight ratio of polyvinyl butyral and oxotitanyl phthalocyanine contained in the charge generation layer is preferably in the above-mentioned range.

According to the present invention, the photosensitive layer is of a so-called function-separated type and has a laminated structure of a charge generation layer and a charge transport layer. Further, since the charge generation layer further contains a vinyl compound polymer or a vinyl compound copolymer, the charge generation layer is compared with a photoreceptor not containing the vinyl compound polymer or the vinyl compound copolymer as described above. The generating layer can be easily formed into a layer.

According to the sixth aspect of the present invention, the weight ratio of the polymer of the vinyl compound or the copolymer of the vinyl compound and the oxotitanyl phthalocyanine contained in the charge generation layer is preferably in the above-mentioned range. understood.

According to the present invention of claim 7, the amine-
It has been found that the hydrazone compound is preferably a compound represented by the above general formula (II).

According to the present invention of claim 8, the amine-
It has been found that the hydrazone compound is more preferably represented by the above general formula (III).

[Brief description of the drawings]

FIG. 1 shows an electrophotographic photosensitive member 8 according to an embodiment of the present invention.
It is sectional drawing which shows a-8d.

FIG. 2 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 1.

FIG. 3 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Comparative Production Example 1.

FIG. 4 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Production Example 2.

FIG. 5 is an X-ray diffraction spectrum of oxotitanyl phthalocyanine obtained in Comparative Production Example 2.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 charge generating substance 3 charge transporting substance 4, 4a, 4b photosensitive layer 5 charge generating layer 6 charge transporting layer 7 intermediate layer 8, 8a, 8b, 8c, 8d electrophotographic photoreceptor

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Kondo 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 2H068 AA13 AA19 AA20 AA21 AA28 AA37 BA24 BA39 BB11 BB12 BB16 BB20 BB51 BB54

Claims (8)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains, as a charge generating substance, oxotitanyl phthalocyanine mainly containing two or more types of crystal-type microcrystals. The oxotitanyl phthalocyanine contains at least one amine-hydrazone compound represented by the following general formula (I) as a transport substance, and the oxotitanyl phthalocyanine has a Bragg angle (2θ ± 0.2 °) of 7.3 in an X-ray diffraction spectrum.
°, 24.1 °, and 27.2 °, and diffraction peaks having different Bragg angles in the range of 9.0 ° to 10.0 °, respectively.
The intensity of each diffraction peak in the range of 0 ° to 10.0 ° is larger than the intensity of the diffraction peak at a Bragg angle of 27.2 °,
An electrophotographic photoreceptor, wherein the intensity of a diffraction peak at a Bragg angle of 27.2 ° is greater than the intensity of each diffraction peak at a Bragg angle of 7.3 ° or 24.1 °. Embedded image [In the general formula (I), R ¹ , R ² , R ⁴ and R ⁵ may be the same or different, and represent a lower alkyl group, an aromatic hydrocarbon residue which may have a substituent or a substituent. Represents an optionally substituted heterocyclic residue or an optionally substituted aralkyl group. R
³ represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower dialkylamino group, a trifluoromethyl group or an aralkyl group which may have a substituent. n is an integer of 1 to 3. ] 2. The diffraction peaks having a Bragg angle in the range of 9.0 ° to 10.0 ° are due to microcrystals having different crystal types, respectively, and have Bragg angles of 9.4 ° and 9. 2. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor exhibits a diffraction peak at 6 [deg.]. 3. The photosensitive layer has a laminated structure of a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, wherein the charge generating layer has a butyralization degree of 50 mol% to 70 mol. %
3. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor contains less than polyvinyl butyral and oxotitanyl phthalocyanine mainly containing two or more types of crystallites. 4. The electrophotographic photoreceptor according to claim 3, wherein the weight ratio of the polyvinyl butyral to the oxotitanyl phthalocyanine is from 1: 3 to 1: 1. 5. The photosensitive layer has a laminated structure of a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, wherein the charge generating layer is a polymer of a vinyl compound or a vinyl compound. 3. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor contains a copolymer and oxotitanyl phthalocyanine mainly containing two or more types of crystal microcrystals. 6. The electrophotographic photosensitive member according to claim 5, wherein the weight ratio of the polymer of the vinyl compound or the copolymer of the vinyl compound to oxotitanyl phthalocyanine is from 1: 2 to 1: 1. body. 7. The electrophotographic photoreceptor according to claim 1, wherein the amine-hitrazone compound of the general formula (I) is represented by the following general formula (II). Embedded image [In the general formula (II), R ¹ , R ² , R ⁴ and R ⁵ may be the same or different, and represent a lower alkyl group, an aromatic hydrocarbon residue which may have a substituent, Represents an optionally substituted heterocyclic residue or an optionally substituted aralkyl group.
R ³ represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower dialkylamino group, a trifluoromethyl group, or an aralkyl group which may have a substituent. n is an integer of 1 to 3. ] 8. The electrophotographic photoreceptor according to claim 7, wherein the amine-hitrazone compound of the general formula (II) is represented by the following general formula (III). Embedded image [In the general formula (III), Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon residue which may have a substituent or a heterocyclic residue which may have a substituent. Represent. R ³
Represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower dialkylamino group, a trifluoromethyl group, or an aralkyl group which may have a substituent. R ⁴ and R ⁵ may be the same or different and are a lower aralkyl group, an aromatic hydrocarbon residue which may have a substituent,
Represents a heterocyclic residue which may have a substituent or an aralkyl group which may have a substituent. j, k, and n are integers of 1 to 3. ]