JP2000034421A - Organic pigment dispersion, preparation of organic pigment dispersion and organic photoconductive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solvent wherein a titanyl phthalocyanine, which has a crystal form wherein the Bragg angle 2θ shows the main peaks at least at 9.3 deg.±0.2 deg., 13.1 deg.±0.2 deg. and 26.2 deg.±0.2 deg. in an X-ray diffraction spectrum against Cu-Kα ray, is stably and finely dispersed, and also to provide an organic photoconductor which contains a titanyl phthalocyanine, which has a crystal form wherein the Bragg angle 2θ shows the main peaks at least at 9.3 deg.±0.2 deg., 13.1 deg.±0.2 deg. and 26.2 deg.±0.2 deg. in an X-ray diffraction spectrum against Cu-Kα ray, and shows a good coating quality. SOLUTION: An organic pigment dispersion is prepared by dispersing an titanyl phthalocyanine, which has an amorphous crystal form in an X-ray diffraction spectrum against Cu-Kα ray, in the organic solvent to allow crystal conversion into a titanyl phthalocyanine having a crystal form wherein the Bragg angle 2θ exerts the main peaks at least at 9.3 deg.±0.2 deg., 13.1 deg.±0.2 deg. and 26.2 deg.±0.2 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanyl phthalocyanine dispersion having a specific crystal structure widely used for photoelectric conversion elements, a method for producing the same, and a titanyl phthalocyanine having a specific crystal structure produced using the same. Organic photoconductors. In particular, titanyl phthalocyanine exhibiting a specific X-ray diffraction spectrum (hereinafter, referred to as
Abbreviated as TiOPc).

[0002]

2. Description of the Related Art In recent years, the development of information processing systems using electrophotography has been remarkable. In particular, optical printers that convert information into digital signals and record information with light have significantly improved print quality and reliability. This digital recording technique is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, a copier equipped with this digital recording technology in a conventional analog copy is added with various information processing functions, and therefore, it is expected that the demand thereof will be further increased in the future.

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

The photosensitive wavelength range of an electrophotographic photosensitive member is almost determined by the photosensitive wavelength range of a charge generating substance used in the photosensitive member. Therefore, many charge generation materials such as various azo pigments, polycyclic quinone pigments, trigonal selenium, and various phthalocyanine pigments have been developed. Among them,
Since TiOPc exhibits high sensitivity to long-wavelength light of 600 to 800 nm, it is extremely important and useful as a material for a photoreceptor for an electrophotographic printer or a digital copying machine whose light source is an LED or LD.

[0005] Titanyl phthalocyanine has many types of crystal forms, and each crystal form often changes to another crystal form by contact with an organic solvent. Therefore, especially in the X-ray diffraction spectrum for Cu-Kα ray, the main peak of Bragg angle 2θ is at least 9.3 ° ± 0.2 °, 13.1 ° ± 0.2 ° and 2 °.
It has been difficult to stably disperse titanyl phthalocyanine having a crystal form at 6.2 ° ± 0.2 ° in a solvent. For this reason, a method for stably and mass-producing an organic photoconductive layer containing TiOPc having such a crystal form by a cast film forming method has not been established, and a dispersion containing TiOPc having the above-described crystal form and a dispersion thereof. The creation method was strongly expected.

On the other hand, conventionally, as a method for producing a photoreceptor using a photoconductive organic pigment, a photoconductive organic pigment is dispersed in a non-aqueous solvent, and then coated on an appropriate substrate and dried to form a photosensitive layer. Have been taken. As a method for producing such a photoconductive organic pigment dispersion, a photoconductive organic pigment powder is added to a non-aqueous solvent and dispersed by a known means such as a ball mill, a sand mill, an attritor, a vibration mill, a paint shaker, and a planetary mill. Liquids have been made.

However, in the preparation of a dispersion containing titanyl phthalocyanine, not only the dispersibility but also the electrostatic properties of the produced electrophotographic photoreceptor are greatly affected by selection of the preparation method and dispersion conditions. . This is because the generation of charges due to the dissociation of excitons depends on the surface area and particle size of the particles. On the other hand, the particles are refined by the progress of crushing and dispersion, but conversely aggregation of the particles occurs when overdispersion occurs, and the dispersibility is reduced. It is difficult to obtain the dispersed state and the required electrostatic characteristics. Therefore, in order to obtain the required electrostatic characteristics, it is necessary to optimize the dispersion method and its conditions.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an X-ray diffraction spectrum for Cu-Kα ray in which the main peak of Bragg angle 2θ is at least 9.3 °.
± 0.2 °, 13.1 ° ± 0.2 ° and 26.2 ° ±
An object of the present invention is to provide a solvent in which titanyl phthalocyanine having a crystal form at 0.2 ° is stably and finely dispersed.
Another object of the present invention is to provide Cu-K having excellent coating quality.
In the X-ray diffraction spectrum for α-rays, the main peak of Bragg angle 2θ is at least 9.3 ° ± 0.2 °, 1
It is to provide an organic photoconductor containing titanyl phthalocyanine having a crystal form at 3.1 ° ± 0.2 ° and 26.2 ° ± 0.2 °.

[0009]

In view of the above, the present inventors have found that the main peak of Bragg angle 2θ is at least 9.3 ° in the X-ray diffraction spectrum for Cu-Kα ray.
± 0.2 °, 13.1 ° ± 0.2 ° and 26.2 ° ±
The present inventors have intensively studied a method for obtaining a stable dispersion in which titanyl phthalocyanine having a crystal form at 0.2 ° is finely dispersed. Further, by coating and drying this dispersion on a substrate, the main peak of the Bragg angle 2θ is at least 9.3 ° ± 0.2 in the X-ray diffraction spectrum with respect to the Cu—Kα ray having excellent coating quality. °, 13.1 ° ± 0.2 ° and 26.2 ° ± 0.2 ° have been found to be able to form an organic photoconductive layer containing titanyl phthalocyanine having a crystal form, and have completed the present invention. .

In other words, according to the present invention, (1) “the main peak of the Bragg angle 2θ in the X-ray diffraction spectrum with respect to Cu-Kα ray is obtained by dispersing titanyl phthalocyanine having an amorphous crystal form together with an organic solvent. Organic pigment dispersion characterized by being converted to titanyl phthalocyanine having a crystal form at least at 9.3 ° ± 0.2 °, 13.1 ° ± 0.2 ° and 26.2 ° ± 0.2 ° Liquid ", (2)" the organic pigment dispersion according to the above (1), wherein the organic solvent contains at least one selected from toluene, xylene, cyclohexane and methylcyclohexane ", and (3)" crystal ". Through a step of dispersing an amorphous titanyl phthalocyanine together with an organic solvent, the Bragg angle 2θ in the X-ray diffraction spectrum with respect to Cu-Kα Principal peaks at least 9.3 ° ± 0.2 °, 13.1 ° ± 0.2 ° and 2
(6) A method for producing an organic pigment dispersion characterized by obtaining a dispersion containing titanyl phthalocyanine having a crystal form at 2 ° ± 0.2 ° ”, (4)“ the organic solvent is toluene, xylene, or cyclohexane. And (3) the method for producing an organic pigment dispersion according to the above (3), wherein at least one selected from the group consisting of methylcyclohexane and methylcyclohexane is included.
(5) "X-ray diffraction spectrum for Cu-Kα radiation, characterized by being formed through a step of applying and drying the organic pigment dispersion according to the above (1) or (2) on a substrate. The main peaks of the Bragg angle 2θ in at least 9.3 ° ± 0.2 °, 13.1 ° ± 0.2 ° and 2
6.2 Organic photoconductive layer containing titanyl phthalocyanine having a crystal form at 2 ° ± 0.2 ° ”, (6)“ At least a charge generating layer and a charge transport layer on a conductive support, An organic photoconductive layer, wherein the generation layer is a layer formed through the step of applying and drying the organic pigment dispersion described in the above item (1) or (2).

Hereinafter, the present invention will be described in detail. The basic structure of the TiOPc pigment used in the present invention is represented by the following general formula (I).

[0012]

Embedded image (In the formula, X ₁ , X ₂ , X ₃ , and X ₄ each independently represent various halogens, and n, m, l, and k each independently represent a number from 0 to _4. )

Various crystal forms are known for TiOPc, and are disclosed in JP-A-59-49544 and JP-A-59-16.
6959, JP-A-61-239248, JP-A-62-67094, JP-A-63-366, JP-A-63-116158, JP-A-63-1
JP-A-96067 and JP-A-64-17066 disclose TiOPc having different crystal forms.

TiOPc before dispersion used in the present invention
Is an X-ray using Cu-Kα characteristic X-rays (wavelength 1.54 °).
In the line diffraction spectrum, those having an amorphous (so-called amorphous) crystal form are used. Methods for obtaining the desired crystal form include a known method in the synthesis process, a method of changing crystals in the washing / purification process, and a method of providing a special crystal conversion step, and any method may be used.

TiOPc obtained by dispersion in the present invention
In the X-ray diffraction spectrum using Cu-Kα characteristic X-rays, the main peak at Bragg angle 2θ is at least 9.
3 ° ± 0.2 °, 13.1 ° ± 0.2 ° and 26.2
One having a crystal form at ° ± 0.2 ° is obtained. That is, by subjecting the TiOPc powder to a dispersion treatment with an optional or specific organic solvent, a dispersion in which the fine particles having the crystal form are dispersed can be produced in a single operation.

The dispersion of the present invention contains TiOPc, a binder resin and a non-aqueous solvent as main components. In addition, a sensitizer, an antioxidant, and the like may be added thereto. As the crystal form of TiOPc used in the present invention, all known crystal forms can be used and are useful. It also includes amorphous ones.

As the non-aqueous solvent as a dispersion medium, known ones can be widely used, and tetrahydrofuran, butanone,
Ethyl acetate, toluene and cyclohexane can be preferably used. These solvents are used alone or as a mixture. These solvents may be mixed with other solvents from the beginning and used.
May be mixed with another solvent as a diluting solvent. Examples of the binder resin that may be used as appropriate include polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, and polyacrylamide. Can be The ratio between the binder resin and the pigment is preferably from 0/3 to 3/1, and more preferably from 0/2 to 2/1. The binder resin may be added before the dispersion, or may be added after the dispersion with only the TiOPc and the solvent. Moreover, it is also possible to add during the dispersion.

Examples of the material of the medium include zirconia, glass, alumina, non-oxide, metal and the like. As a dispersion means for obtaining a dispersion by wet dispersion, a known method such as a ball mill, an attritor, a sand mill, a vibration mill, a disk vibration mill, a paint shaker, and a jet mill can be used. However, since the conditions for preparing the target dispersion differ depending on the respective dispersion conditions, they cannot be defined uniformly. It can be considered that the reason is that the ratio of crushing power, dispersing power, grinding power, etc. necessary for crystal conversion differs depending on the dispersing means or its use conditions, and also depending on the type of solvent used,
The crystal conversion conditions are different.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an organic photoconductive layer used in the present invention. A single-layer photosensitive layer (33) containing a charge generation material and a charge transport material as main components on a conductive support (31).
Is provided. FIG. 2 and FIG. 3 are cross-sectional views showing another example of the configuration of the organic photoconductive layer used in the present invention. And a charge transport layer (37). Organic photoconductive layer of such a configuration,
In this state, it can be used as an organic photoreceptor for electrophotography, or it can be used for an optical sensor, a photovoltaic cell, or the like by providing a counter electrode (not shown) on the conductive support (31).

As the conductive support (31), those having conductivity of not more than 10 ¹⁰ Ωcm, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver and platinum, tin oxide, etc. Film or cylindrical plastic or paper coated with metal oxides such as indium oxide by vapor deposition or sputtering, or plates of aluminum, aluminum alloy, nickel, stainless steel, etc., and methods such as extrusion and drawing A pipe or the like that has been surface-treated by cutting, superfinishing, polishing, or the like after it has been formed into a tube can be used. Also, Japanese Unexamined Patent Publication No. Sho 52-3
The endless nickel belt and the endless stainless belt disclosed in Japanese Patent Application Laid-Open No. 6016 are also applicable to the conductive support (3).
It can be used as 1).

In addition, a support obtained by dispersing a conductive powder on a suitable binder resin on the above support and applying the same can also be used as the conductive support (31) of the present invention. As the conductive powder, carbon black, acetylene black, aluminum, nickel, iron, nichrome,
Metal powder of copper, zinc, silver, etc. or conductive tin oxide, ITO
And the like. Further, the binder resin used simultaneously, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer,
Styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral And thermoplastic, thermosetting or photo-curable resins such as polyvinylformal, polyvinyltoluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenolic resin and alkyd resin. Can be Such a conductive layer, these conductive powder and binder resin suitable solvent,
For example, THF (tetrahydrofuran), MDC
(Dichloromethane), MEK (methyl ethyl ketone),
It can be provided by dispersing and coating in toluene or the like. Note that the counter electrode which can be provided as necessary can be provided using a known material by a known method.

Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a stacked layer, but for convenience of explanation, the case where the photosensitive layer is composed of the charge generation layer (35) and the charge transport layer (37) will be described first. The charge generation layer (35) is obtained by dispersing the TiOPc together with a binder resin as necessary in a suitable solvent using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, and applying the resultant on a conductive support; It is formed by drying. As described above, the crystal form of TiOPc changes during dispersion.

If necessary, the binder resin used for the charge generation layer (35) may be polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polyvinyl ketone, polystyrene, Polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol And polyvinylpyrrolidone. The amount of the binder resin is suitably from 0 to 500 parts by weight, preferably from 0 to 300 parts by weight, per 100 parts by weight of the charge generating substance.

The charge generation layer (35) includes the above-described TiOP
It is also possible to use other charge generating materials in addition to c, and typical examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensed polycyclic compounds. And squaric acid dyes, phthalocyanine pigments, naphthalocyanine pigments, and azulenium salt dyes. The dispersion solvent used here is as described above, and is preferably at least one selected from toluene, xylene, cyclohexane, and methylcyclohexane.
It is desirable to include seeds. As a method for applying the dispersion, a method such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, and ring coating can be used. The thickness of the charge generation layer (35) is 0.01 to 5
The thickness is suitably about μm, and preferably 0.1 to 2 μm.

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

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

Examples of the hole transport material include poly-N-carbazole and its derivatives, poly-γ-carbazolylethylglutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole Derivatives,
Oxadiazole derivative, imidazole derivative, monoarylamine derivative, diarylamine derivative, triarylamine derivative, stilbene derivative, α-phenylstilbene derivative, benzidine derivative, diarylmethane derivative, triarylmethane derivative, 9-styrylanthracene derivative, pyrazoline Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bis-stilbene derivatives,
Other known materials such as enamine derivatives may be used. These charge transport materials are used alone or in combination of two or more.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polystyrene. Vinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, Urethane resin,
Thermoplastic or thermosetting resins such as phenolic resins and alkyd resins are exemplified.

The amount of the charge transport material is 20 to 300 parts by weight, preferably 40 to 15 parts by weight, per 100 parts by weight of the binder resin.
0 parts by weight is suitable. The thickness of the charge transport layer is 5
It is preferably about 100 μm. As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.

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

Next, the case where the photosensitive layer has a single layer structure (33) will be described. The single-layer photosensitive layer is prepared by converting the charge generating substance, the charge transporting substance used as required, and the binder resin into an appropriate solvent (preferably containing at least one selected from toluene, xylene, cyclohexane and methylcyclohexane). It can be formed by dissolving or dispersing, applying and drying this. Further, the photosensitive layer may be of a function-separated type in which the above-described charge transport material is added,
Can be used well. If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

As the binder resin, the charge transport layer (3
In addition to using the binder resin described in 7) as it is, the binder resin described in the charge generation layer (35) may be mixed and used. The amount of the charge generating substance is preferably 1 to 40 parts by weight, and the amount of the charge transporting substance is 0 to 1 part by weight based on 100 parts by weight of the binder resin.
It is preferably 90 parts by weight, more preferably 0 to 150 parts by weight. The single-layered photosensitive layer is formed by applying a coating liquid obtained by dispersing a charge generating substance and a binder resin together with a charge transporting substance, if necessary, using the above-described solvent using a dispersing machine or the like by a dip coating method, spray coating, bead coating, or the like. It can be formed by processing. The thickness of the single-layer photosensitive layer is suitably about 5 to 100 μm. In this case, it is needless to say that the process includes a process of changing the crystal of TiOPc in the dispersion process.

The electrophotographic photoreceptor of the present invention may have an undercoat layer between the conductive support (31) and the photosensitive layer. The undercoat layer can be formed and used by a known method using a known material. The thickness of the undercoat layer is 0 to 5 μm
m is appropriate. In the electrophotographic photoreceptor of the present invention, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. The protective layer can be formed by a known method using a known material and used. The thickness of the protective layer is 0.1
About 10 to 10 μm is appropriate.

[0034]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited by these examples. Note that all “parts” in the examples are parts by weight. First, a specific synthesis example of a titanyl phthalocyanine pigment used in Examples will be described.

Synthesis Example 52.5 parts of phthalodinitrile and 400 parts of 1-chloronaphthalene were stirred and mixed, and titanium tetrachloride 19
Drop the part. After completion of the dropwise addition, the temperature was gradually raised to 200 ° C., while maintaining the reaction temperature between 190 ° C. and 210 ° C.
The reaction was performed with stirring for 5 hours. After the reaction is completed, allow to cool 1
When the temperature reached 30 ° C., the solution was filtered while hot, then washed with 1-chloronaphthalene until the powder turned blue, then washed several times with methanol, and further washed several times with hot water at 80 ° C. Drying yielded 42.2 parts of crude TiOPc pigment. 6 parts of 9 of the obtained hot water washed crude TiOPc pigment
The mixture was stirred and dissolved in 100 g of 6% sulfuric acid at 3 to 5 ° C. and filtered. The obtained sulfuric acid solution was dropped into 3.5 liters of ice water with stirring, and the precipitated crystals were filtered and then washed repeatedly with water until the washing liquid became neutral to obtain a wet cake of the TiOPc pigment. Methanol 3 in this wet cake
After further adding 00 parts, the mixture was stirred at room temperature for 1 hour, and then filtered. After repeating this twice, drying was performed to obtain 5.1 parts of a TiOPc pigment.

An X-ray powder diffraction spectrum of the obtained TiOPc pigment was measured under the following conditions. X-ray tube: Cu Voltage: 40 kV Current: 20 mA Scanning speed: 1 ° / min Scanning range: 3 ° to 40 ° Time constant: 2 seconds

FIG. 4 shows the X-ray diffraction spectrum of the TiOPc pigment obtained as described above. It can be seen that the crystal form of the obtained TiOPc pigment is amorphous.

Example 1 A partially stabilized zirconium ball was filled in a Pyrex glass ball mill pot having an internal volume of 1 liter, and the following materials were charged and tumbled and dispersed at room temperature for 60 hours to obtain an intended dispersion. Was. 2 parts of the synthesized TiOPc pigment powder 1.4 parts of polyester 200 parts of toluene A part of the prepared dispersion was dried at room temperature and in the air,
Pc powder was obtained (see FIG. 5). The X-ray diffraction spectrum of this powder sample was measured in the same manner as described above. FIG. 5 shows the results. The obtained TiOPc pigment has a main peak of Bragg angle 2θ of at least 9.3 ° ± 0.2 °, 13.1 °.
It can be seen that the crystal forms at ° ± 0.2 ° and 26.2 ° ± 0.2 ° are retained.

Comparative Example 1 The same material as in Example 1 was charged into the same ball mill pot as used in Example 1, and tumbled and dispersed at room temperature for 2 hours to obtain a dispersion. A part of the prepared dispersion was dried at normal temperature and in the atmosphere to obtain a TiOPc powder (see FIG. 6). The X-ray diffraction spectrum of this powder sample was measured in the same manner as described above. FIG. 6 shows the results. It can be seen that the crystal form of the obtained TiOPc pigment is amorphous, as before the dispersion.

Example 2 The following materials were charged into the same ball mill pot as used in Example 1, and then tumbled and dispersed at room temperature for 60 hours to obtain a dispersion. 2 parts of the synthesized TiOPc pigment powder 1.8 parts of polyester 200 parts of p-xylene A part of the prepared dispersion was dried at room temperature and in the atmosphere,
Pc powder was obtained (see FIG. 7). The X-ray diffraction spectrum of this powder sample was measured in the same manner as described above. FIG. 7 shows the results. The obtained TiOPc pigment has a main peak of Bragg angle 2θ of at least 9.3 ° ± 0.2 °, 13.1 °.
It can be seen that the crystal forms at ° ± 0.2 ° and 26.2 ° ± 0.2 ° are retained.

Example 3 The following materials were charged into the same ball mill pot as used in Example 1, and then tumbled and dispersed at room temperature for 60 hours to obtain a dispersion. 2 parts of the synthesized TiOPc pigment powder 180 parts of methylcyclohexane A part of the prepared dispersion was dried at room temperature and in the air to obtain TiO 2.
Pc powder was obtained (see FIG. 8). The X-ray diffraction spectrum of this powder sample was measured in the same manner as described above. FIG. 8 shows the results. The obtained TiOPc pigment has a main peak of Bragg angle 2θ of at least 9.3 ° ± 0.2 °, 13.1 °.
It can be seen that the crystal forms at ° ± 0.2 ° and 26.2 ° ± 0.2 ° are retained.

Example 4 The following materials were placed in the same ball mill pot as used in Example 1, and then tumbled and dispersed at room temperature for 60 hours to obtain a dispersion. 2 parts of the above synthesized TiOPC pigment powder 200 parts of cyclohexane A part of the prepared dispersion was dried at room temperature and in the air to obtain TiO 2.
Pc powder was obtained (see FIG. 9). The X-ray diffraction spectrum of this powder sample was measured in the same manner as described above. FIG. 9 shows the results. The obtained TiOPc pigment has a main peak of Bragg angle 2θ of at least 9.3 ° ± 0.2 °, 13.1 °.
It can be seen that the crystal forms at ° ± 0.2 ° and 26.2 ° ± 0.2 ° are retained.

Comparative Example 2 The same material as in Example 4 was charged into the same ball mill pot as used in Example 1, and then tumbled and dispersed at room temperature for 2 hours to obtain a dispersion. A part of the prepared dispersion was dried at normal temperature and in the atmosphere to obtain a TiOPc powder (see FIG. 10). The X-ray diffraction spectrum of this powder sample was measured in the same manner as described above. The results are shown in FIG. It can be seen that the crystal form of the obtained TiOPc pigment is amorphous, as before the dispersion.

Each of the dispersions of Examples 1-4 and Comparative Examples 1-2 prepared as described above was placed in a glass tube having an inner diameter of 5 mm and a length of 30 cm and allowed to stand for 2 days. The length of the resulting supernatant (the length at which the dispersion became transparent) was measured. Next, using each of the prepared dispersions of Examples 1 to 4 and Comparative Examples 1 and 2, an organic light dispersed in TiOPc by a dip coating method at a lifting speed of 5 mm / s on an aluminum plate having a length of 0.2 mm. A conductive layer was formed. The state of the coating film at this time was visually determined. Further, Examples 1 to 5 produced as described above
4. Using the respective dispersions of Comparative Examples 1 and 2, an organic photoconductive layer having a dry film thickness of about 1 μm and dispersed with TiOPc was formed on a polyethylene terephthalate film on which aluminum was deposited by a spray coating method. The state of the coating film at this time was visually determined. Table 1 shows the results of the above measurements.

[0045]

[Table 1]

[0046]

As is apparent from the detailed and concrete explanations above, according to the present invention, by dispersing titanyl phthalocyanine having an amorphous X-ray diffraction spectrum with respect to Cu-Kα ray together with an organic solvent, The main peak of Bragg angle 2θ in the X-ray diffraction spectrum with respect to Kα ray is at least 9.3 ° ± 0.2 °, 13.1
A stable dispersion of finely dispersed titanyl phthalocyanine having a crystal form at ° ± 0.2 ° and 26.2 ° ± 0.2 ° was obtained. Thereby, in the X-ray diffraction spectrum with respect to the Cu-Kα ray, the main peak of the Bragg angle 2θ is at least 9.3 ° ± 0.2 °, 13.1 °.
A novel process for the preparation of a stable dispersion of finely dispersed titanyl phthalocyanine having crystal forms at ± 0.2 ° and 26.2 ° ± 0.2 ° has been completed. Further, by applying and drying this dispersion on a substrate, an X-ray diffraction spectrum with respect to Cu-Kα rays having excellent coating quality is obtained.
Main peak of Bragg angle 2θ is at least 9.3 ° ±
0.2 °, 13.1 ° ± 0.2 ° and 26.2 ° ± 0.2.
An organic photoconductive layer having excellent coatability containing titanyl phthalocyanine having a crystal form at 2 ° was obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a layer structure of a photoconductor according to the present invention.

FIG. 2 is a cross-sectional view illustrating another layer structure of the photoreceptor in the present invention.

FIG. 3 is a cross-sectional view showing still another layer structure of the photoconductor of the present invention.

FIG. 4 is a view showing an X-ray diffraction spectrum of a TiOPc powder in the present invention.

FIG. 5 is a view showing an X-ray diffraction spectrum of a TiOPc powder in the present invention.

FIG. 6 is a diagram showing an X-ray diffraction spectrum of a TiOPc powder in a comparative example.

FIG. 7 is a view showing an X-ray diffraction spectrum of the TiOPc powder in the present invention.

FIG. 8 is a view showing an X-ray diffraction spectrum of the TiOPc powder in the present invention.

FIG. 9 is a diagram showing an X-ray diffraction spectrum of TiOPc powder in the present invention.

FIG. 10 is a diagram showing an X-ray diffraction spectrum of a TiOPc powder in a comparative example.

[Explanation of symbols]

 31 conductive support 33 photosensitive layer 35 charge generation layer 37 charge transport layer

Continued on the front page F term (reference) 2H068 AA19 AA21 AA28 AA34 BA39 EA05 EA13 EA14 4J038 JA02 JA05 JC38 KA06 KA08 KA12 MA07 NA18 NA20 PA18 PB11 PC01 PC02 PC08

Claims (6)

[Claims] (1) Dispersing titanyl phthalocyanine having an amorphous crystal form together with an organic solvent to form Cu-
The main peak of Bragg angle 2θ in the X-ray diffraction spectrum with respect to Kα ray is at least 9.3 ° ± 0.2 °, 1
An organic pigment dispersion characterized by being crystallized into titanyl phthalocyanine having a crystal form at 3.1 ° ± 0.2 ° and 26.2 ° ± 0.2 °. 2. The organic pigment dispersion according to claim 1, wherein the organic solvent contains at least one selected from toluene, xylene, cyclohexane, and methylcyclohexane. 3. A process for dispersing a titanyl phthalocyanine having an amorphous crystal form together with an organic solvent to obtain Cu-
The main peak of Bragg angle 2θ in the X-ray diffraction spectrum with respect to Kα ray is at least 9.3 ° ± 0.2 °, 1
3. A process for producing an organic pigment dispersion, comprising obtaining a dispersion containing titanyl phthalocyanine having a crystal form at 3.1 ° ± 0.2 ° and 26.2 ° ± 0.2 °. 4. The method for producing an organic pigment dispersion according to claim 3, wherein the organic solvent contains at least one selected from toluene, xylene, cyclohexane, and methylcyclohexane. 5. A Bragg angle 2θ in an X-ray diffraction spectrum with respect to Cu-Kα radiation, wherein the Bragg angle is formed by applying and drying the organic pigment dispersion according to claim 1 on a substrate. At least 9.3
° ± 0.2 °, 13.1 ° ± 0.2 ° and 26.2 °
An organic photoconductive layer containing titanyl phthalocyanine having a crystal form at ± 0.2 °. 6. A conductive support having at least a charge generation layer and a charge transport layer, wherein the charge generation layer is formed by applying and drying the organic pigment dispersion according to claim 1 or 2. An organic photoconductive layer, which is a coated layer.