JPH0747698B2 - α-type titanyl phthalocyanine composition, method for producing the same, and electrophotographic photoreceptor using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to an α-type titanyl phthalocyanine composition suitable for use as a photoconductor used in an image forming apparatus such as a copying machine and a laser beam printer, a method for producing the same, and the same. The present invention relates to an electrophotographic photosensitive member using.

<Prior Art and Problems to be Solved by the Invention> Conventionally, as a photoconductor for an image forming apparatus such as a copying machine, an electrophotographic photoconductor using a photoconductive substance such as phthalocyanine has been widely used.

Further, in recent years, a laser beam printer using a semiconductor laser as a light source is becoming widespread, which is advantageous in that a device can be downsized and a high-quality image can be formed at high speed by a non-impact method. Various studies have been conducted on photoconductive substances used for photoconductors for beam printers.

The electrophotographic process using the above photoconductor for a laser beam printer includes a charging step for uniformly charging the photoconductor by corona discharge, and an electrostatic latent image corresponding to the document image by irradiating the charged photoconductor with a document image by a semiconductor laser. A large amount of electrophotographic copying is carried out by repeating the electrophotographic process including an exposure step of forming an image on a photoreceptor.

In the charging step, it is required that the photoconductor has good charging characteristics and a small dark decay, and in the exposure step, it has high sensitivity in the wavelength range of about 780 to 820 nm which is the oscillation wavelength of the semiconductor laser. In addition to being required to have a small residual potential after irradiation with a semiconductor laser, the deterioration of the above characteristics due to repeated use is required to be small.

In order to meet these requirements, a phthalocyanine compound that has high sensitivity in the wavelength region of the semiconductor laser has been proposed as a photoconductive substance. The phthalocyanine compound includes a metal-free phthalocyanine having no central metal and a metal phthalocyanine having a central metal, and also has various crystal types such as α type, β type and γ type.

Not only the stability but also the absorption spectrum varies depending on the presence or absence of the central metal, the type of the central metal, and the crystal type. Therefore, these differences have a great influence on the charging property and the sensitivity.

More specifically, some metal-free phthalocyanines have excellent photoconductivity and exhibit high sensitivity in the above wavelength range (about 780 to 820 nm).

However, since the crystal of metal-free phthalocyanine is a metastable crystal type, it is difficult to obtain a photoreceptor having stable characteristics by using it.

Metal phthalocyanines such as copper phthalocyanine include α type,
There are crystal types such as β type, γ type, and ε type. Of these crystal forms, ε-type copper phthalocyanine is known to have an absorption region on the long wavelength side and also have a spectral sensitivity on the long wavelength side (Journal of the Electrophotographic Society, Vol. 22, No. 2). , Page 111, 1984).

However, copper phthalocyanine is still insufficient in terms of sensitivity.

A photoconductor containing a titanyl phthalocyanine having titanium as a coordination metal in the photoconductive layer, such as a composite type electrophotographic photoconductor having a photoconductive layer in which α-type titanyl phthalocyanine is dispersed in a binder, for example, α-type titanyl phthalocyanine A composite type electrophotographic photoreceptor having a photosensitive layer dispersed in a binder (see JP-A-61-239248), a charge generation layer in which a specific titanyl phthalocyanine is dispersed in a binder, and a charge There has been proposed an electrophotographic photoreceptor (see JP-A-62-67094) in which a transport layer is laminated.

The electrophotographic photosensitive member using the above-mentioned titanyl phthalocyanine as the photoconductive substance exhibits high sensitivity to some extent in the wavelength region of the semiconductor laser, and is also excellent in electrical characteristics such as charging property.

However, the electrophotographic photosensitive member has a charging property, dark decay,
There is a problem that electric characteristics such as residual potential and sensitivity are still insufficient.

An object of the present invention is to provide an α-type titanyl phthalocyanine composition excellent in not only electrical characteristics such as chargeability, dark decay, and residual potential, but also sensitivity, a method for producing the same, and an electrophotographic photoreceptor using the same. Is.

<Means for Solving the Problem> α according to the invention of claim 1 for achieving the above object
A type titanyl phthalocyanine composition has the formula: And 1,3-diiminoisoindolenine represented by the general formula: Ti (R ¹ ) ₂ (R ² ) ₂ (wherein R ¹ and R ² are the same or different and represent a lower alkoxy group) In the concentrated sulfuric acid solution of titanyl phthalocyanine obtained by reacting with an organotitanium compound represented by or a concentrated sulfuric acid solution obtained by adding metal-free phthalocyanine to the titanyl phthalocyanine is pigmented by the acid paste method into water, α-type Titanyl phthalocyanine 60-90% by weight and metal-free phthalocyanine 10-40
% By weight.

Since the above α-type titanyl phthalocyanine composition contains α-type titanyl phthalocyanine together with metal-free phthalocyanine, it is stable, has a wide absorption wavelength region, and has a large spectral sensitivity.

The method for producing an α-type titanyl phthalocyanine composition according to the present invention according to claim 2, wherein the 1,3-diiminoisoindolenin represented by the formula is reacted with the organotitanium compound to obtain titanyl phthalocyanine. The addition of a metal-free phthalocyanine if necessary to this, the titanyl phthalocyanine alone or pigmented by the acid paste method of injecting concentrated sulfuric acid solution containing the titanyl phthalocyanine and the metal-free phthalocyanine into water,
Then, 60-90% by weight of α-type titanyl phthalocyanine and 10-40% by weight of metal-free phthalocyanine, which are characterized by being subjected to wet milling in the presence of a chlorine-based solvent. A method for producing an α-type titanyl phthalocyanine composition.

According to the above production method, an α-type titanyl phthalocyanine composition containing α-type titanyl phthalocyanine and metal-free phthalocyanine can be easily produced.

The electrophotographic photoreceptor according to claim 3 is the 1,3-
Diiminoisoindolenine, titanyl phthalocyanine obtained by reacting the organotitanium compound or a concentrated sulfuric acid solution in which metal-free phthalocyanine is added thereto is pigmented by an acid paste method of injecting into water, α-type titanyl phthalocyanine A photosensitive layer containing 60 to 90% by weight and 10 to 40% by weight of meta-free phthalocyanine is formed on a conductive substrate.

According to the electrophotographic photoreceptor of the invention of claim 3,
Since the phthalocyanine in the photosensitive layer contains α-type titanyl phthalocyanine and metal-free phthalocyanine,
Not only is it excellent in charging property and dark decay property, but also exhibits high sensitivity in the oscillation wavelength region of the semiconductor laser and has a small residual potential.

The α-type titanyl phthalocyanine is represented by the following general formula.

(In the formula, X represents a halogen atom, and n represents 0 or an integer of 1 or more.) The halogen atom is preferably bromine or chlorine, and n is preferably 0.

The α-type titanyl phthalocyanine composition contains a metal-free phthalocyanine together with the α-type titanyl phthalocyanine. As described above, by containing α-type titanyl phthalocyanine and metal-free phthalocyanine, the stability of the α-type titanyl phthalocyanine composition can be increased, and at the same time, the charging property and the photosensitive property, particularly the sensitivity become remarkably excellent. .

The α-type titanyl phthalocyanine composition of the present invention contains 60-90% by weight of α-type titanyl phthalocyanine and 10-40% by weight of metal-free phthalocyanine. The α-type titanyl phthalocyanine composition having the above composition was used as a photoconductive substance of an electrophotographic photoconductor, which is particularly excellent in stability, even though it contains an unstable crystalline metal-free phthalocyanine. In this case, the charging property is excellent, the dark decay is small, the sensitivity is high, the residual potential is small, and the charging property and the photosensitivity property are excellent.

If the contents of α-type titanyl phthalocyanine and metal-free phthalocyanine deviate from the above range, the half-exposure amount E1 becomes an index of sensitivity in the oscillation wavelength region of the semiconductor laser.
/ 2 (μJ / cm ² ) becomes large, making it difficult to achieve high sensitivity.

The α-type titanyl phthalocyanine composition having the above proportion exhibits a half-exposure E 1/2 of 0.6 μJ / cm ² or less to a semiconductor laser having a wavelength of 780 nm.

The α-type titanyl phthalocyanine composition having the above composition may be prepared by mixing separately produced α-type titanyl phthalocyanine and metal-free phthalocyanine at a predetermined ratio.

Bragg angle (2θ ± 0.2 in X-ray diffraction spectrum
゜) 6.9 °, 9.6 °, 15.6 °, 17.6 °, 21.9 °, 23.6 °,
Strong diffraction peaks at 24.7 ° and 28.0 °, of which 6.
The α-type titanyl phthalocyanine composition having the largest diffraction peak at 9 ° is particularly excellent in charging characteristics and photosensitive characteristics.

The α-type titanyl phthalocyanine composition, other phthalocyanine, for example, copper phthalocyanine, vanadyl phthalocyanine, chloroaluminum phthalocyanine, in a range that does not impair electrical characteristics such as charging characteristics and photosensitive characteristics.
It may contain chloroindium phthalocyanine, chlorogallium phthalocyanine, magnesium phthalocyanine, or other crystalline titanyl phthalocyanine.

Further, β-type, γ-type, δ-type and ε-type titanyl phthalocyanine may be partially contained.

The α-type titanyl phthalocyanine composition does not have to be treated, but in order to enhance stability, a titanium coupling agent, a surface treatment agent such as a silane coupling agent, or a treatment with a silane coupling agent, among others. Those that have been processed are preferred.

This is because the α-type titanyl phthalocyanine composition treated with the surface treatment agent is particularly excellent in stability over time and exhibits stable charging characteristics when used as a photoconductive substance of the photosensitive layer.

The treatment amount with the surface treatment agent can be appropriately set, but is usually 0.001 to 5% by weight, preferably 0.01 to 1% by weight.

The α-type titanyl phthalocyanine composition can be produced by various methods. For example, it can be produced by producing titanyl phthalocyanine, and pigmenting it by an acid paste method in which a sulfuric acid solution containing at least titanyl phthalocyanine, in which a desired amount of metal-free phthalocyanine is added as necessary, is poured into water.

The above-mentioned titanyl phthalocyanine may be produced by reacting 1,2-dicyanobenzene with a titanium halide such as titanium tetrachloride, titanium trichloride, titanium tetrabromide and the like, but the following reaction It is preferably produced by hydrolyzing the titanyl phthalocyanine obtained by the formula.

(In the formula, R ¹ and R ² are the same or different and each represents a lower alkoxy group.) As the lower alkoxy group, methoxy, ethoxy,
Examples thereof include alkoxy groups having 1 to 6 carbon atoms such as propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy and hexyloxy groups.

In the above reaction, 1,3-diiminoisoindolenine and an organotitanium compound are quinoline; benzene, an alkylbenzene such as toluene and xylene; an inert solvent such as trichlorobenzene, 100 to 250 ° C., preferably 150 to 200. It is carried out at a temperature of ° C.

After the above reaction, the produced titanyl phthalocyanine composition is separated by filtration, washed with the above reaction solvent to remove impurities and unreacted raw materials, and if necessary, washed with an organic solvent such as alcohol or ether.

However, the obtained titanyl phthalocyanine composition is coarse, and the crystal type and the particle size are not uniform, and the charging characteristics and the photosensitive characteristics of the photoconductor are not sufficient, and it is difficult to obtain stable properties.

Therefore, the titanyl phthalocyanine composition obtained by the above reaction is pigmented by the acid paste method to produce an α-type titanyl phthalocyanine composition containing α-type titanyl phthalocyanine and metal-free phthalocyanine, which is excellent in charging characteristics and photosensitive characteristics. To do.

Pigmentation by the acid paste method is performed by dissolving the titanyl phthalocyanine in sulfuric acid having an appropriate concentration and injecting the resulting solution into water.

The conditions for pigmenting by the acid paste method are not particularly limited, and can be set appropriately according to desired characteristics.

The titanyl phthalocyanine is dissolved in concentrated sulfuric acid, and the resulting solution is poured into water at -5 to 40 ° C, preferably -5 to 20 ° C, more preferably about 0 ° C to form a pigment. This is because if the temperature of water for injecting the solution is lower than -5 ° C, the charging property and the photosensitive property are not sufficient, and if it exceeds 40 ° C, the charging property is deteriorated. By pigmenting under these conditions, an α-type titanyl phthalocyanine composition having excellent stability and excellent charging characteristics and photosensitive characteristics can be easily produced.

The concentration of sulfuric acid used in pigmentation can be appropriately set, for example, 92-105% (fuming sulfuric acid) concentration, preferably 94-105%, more preferably 98-100% concentrated sulfuric acid of titanyl phthalocyanine. 15 times or more, preferably 15
~ 60 times the amount of the concentrated sulfuric acid solution is maintained at 0 ~ 40 ℃, by pigmenting, to obtain an α-type titanyl phthalocyanine composition further excellent in stability, charging characteristics and photosensitivity To be

The reason why concentrated sulfuric acid with a concentration of 92 to 105% is used is that if the concentration is less than 92%, the photosensitivity decreases, and if it exceeds 105%, the chargeability decreases, and concentrated sulfuric acid is used in an amount 15 times that of titanyl phthalocyanine. The above use is because if the amount of concentrated sulfuric acid used is less than 15 times, it becomes difficult to uniformly dissolve titanyl phthalocyanine.

If the holding temperature of the concentrated sulfuric acid solution is less than 0 ° C., it is not preferable from the viewpoint of a cold storage device and equipment. If the temperature exceeds 40 ° C, the sensitivity tends to decrease.

The temperature holding time of the concentrated sulfuric acid solution and the refining time by pigmentation can be set appropriately. Usually, it takes about 30 minutes to 12 hours.

In addition, a demetalization reaction may occur on the pigment, and the composition of titanyl phthalocyanine may change. In such a case, in order to accurately control the ratio of α-type titanyl phthalocyanine and metal free phthalocyanine, a predetermined amount of metal free phthalocyanine was added to the titanyl phthalocyanine obtained by the synthetic reaction, and again by the acid paste method, It is preferably pigmented.

In the above synthetic reaction, titanyl phthalocyanine containing metal-free phthalocyanine may be produced depending on the production conditions. More specifically, when quinoline was used as the inert solvent, metal-free phthalocyanine was produced in an amount of 10 to 20% by weight, tetrabutoxytitanium was used as the organic titanium compound, and trichlorobenzene and alkylbenzene were used as the inert solvent. In some cases, metal-free phthalocyanine may be produced in an amount of 0 to 10% by weight. In such a case, if the content of α-type titanyl phthalocyanine is within an appropriate range, without adding metal-free phthalocyanine,
It may be pigmented by the acid paste method.

Next, in order to remove the residual sulfuric acid and impurities, the α-type titanyl phthalocyanine composition is separated by filtration, washed, and then dried.

As the solvent in the washing step, various organic solvents such as water, alcohols such as methanol, ethanol and isopropanol, ethers such as diethyl ether, dioxane and tetrahydrofuran, acetone, dichloromethane and dimethylformamide can be used. .

The washing with the above solvent can be performed by an appropriate method. In order to improve the cleaning efficiency, it is preferable to perform the cleaning in a state where the α-type titanyl phthalocyanine composition is dispersed in the solvent. At that time, it is preferable to disperse with ultrasonic waves and wash.

The above-mentioned drying can be performed under normal pressure or reduced pressure conditions at an appropriate temperature, for example, a temperature of 50 to 150 ° C.

After the pigment is formed by the acid paste method, the product is wet-milled in the presence of a chlorinated solvent to improve the stability of the α-type titanyl phthalocyanine and to increase the sensitivity.

Examples of the chlorine-based solvent include dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, carbon tetrachloride, chloroform, chloromethyloxirane, chlorobenzene, dichlorobenzene and the like, and particularly, dichloromethane, chloroform, trichloroethane or chloromethyloxirane is used. Of these, dichloromethane is particularly preferable because it can provide a photoreceptor having a small residual potential. The chlorine-based solvent may be used alone or in combination of two or more.

Among the above solvents, aromatic compounds tend to transfer the crystal form of titanyl phthalocyanine to β form, and aliphatic hydrocarbons tend to form α form titanyl phthalocyanine, which is inferior in dispersibility.

The above organic solvent treatment is carried out by immersing the α-type titanyl phthalocyanine composition in an organic solvent heated to room temperature or an appropriate temperature higher than room temperature, or washing with the organic solvent. The treatment time with the above organic solvent can be appropriately set. However, the crystallization rate varies depending on the type of solvent, and when treated for a long period of time, the crystal form may change to the β form and the sensitivity may decrease. Therefore, it is preferably carried out for about 10 minutes to 10 hours depending on the type of organic solvent.

Further, the wet milling may be one that can mix and disperse the α-type titanyl phthalocyanine composition while applying a mechanical force to the α-type titanyl phthalocyanine composition. For example, it may be an attritor, a kneader, etc. Α with excellent charging characteristics
A ball mill is preferred which provides a titanyl phthalocyanine composition of the type.

The treatment time by the wet milling is not particularly limited, but can be appropriately set according to the desired characteristics, and is usually 1 to 48 hours.

The characteristics of the α-type titanyl phthalocyanine composition in each of the above steps will be described based on the X-ray diffraction spectra shown in FIGS.

As shown in FIG. 2A, the α-type titanyl phthalocyanine composition obtained by the acid paste method showed diffraction peaks at Bragg angles (2θ ± 0.2 °) of 6.9 °, 23.6 °, 24.7 ° and 28.0 °. The diffraction peak at 6.9 ° is the largest. Further, the α-type titanyl phthalocyanine composition obtained by the above acid paste method was added to cyclohexanone.
After soaking for a period of time, a Bragg angle of 6.
The diffraction peaks at 9 °, 21.9 °, 23.6 °, 24.7 ° and 28.0 ° become strong, and the diffraction peak at 6.9 ° is the largest, and crystallization proceeds.

When the α-type titanyl phthalocyanine composition obtained by the acid paste method was immersed in dichloromethane for 1 week, as shown in FIG. 2C, the Bragg angle was 6.9 °, 9.0
Not only °, 10.0 °, 12.9 °, 25.0 ° and 28.2 °,
The diffraction peak at 26.0 °, which is a characteristic of β-type crystals, appears remarkably, the diffraction peak at 6.9 ° is the largest, and β-type titanyl phthalocyanine is partially mixed.

On the other hand, when the α-type titanyl phthalocyanine composition obtained by the acid paste method was ball milled in the presence of a chlorine-based solvent, dichloromethane, as shown in FIG. 2D, Bragg angles 6.9 °, 10.6 °, 15.6 °, 17.6 ° were obtained. 21.9
Α-type titanyl phthalocyanine composition showing strong diffraction peaks at ゜, 23.6 ゜, 24.7 ゜ and 28.0 ゜, and the largest diffraction peak at 6.9 ゜ among the above Bragg angles, and further excellent in charging characteristics and photosensitivity. The thing is obtained.

When the wet milling is performed in the presence of the chlorine-based solvent, particularly dichloromethane, unlike the organic solvent treatment,
Probably because the crystal structure does not change even after wet milling for a long time, it is possible to easily produce a stable α-type titanyl phthalocyanine composition having excellent charging characteristics and photosensitive characteristics.

When the α-type titanyl phthalocyanine composition obtained by the acid paste method was ball milled in the presence of toluene, a Bragg angle of 9.4 was obtained as shown in FIG. 2E.
°, 10.7 °, 13.2 °, 15.1 °, 20.9 °, 23.4 °, 26.3
Diffraction peaks appear at 2 ° and 27.2 °, and among the above Bragg angles, the diffraction peak at 26.3 °, which is a characteristic of β-type crystals, becomes the largest, and the charging properties and the photosensitivity are inferior.

In order to enhance stability over time, α obtained by the above method
It is preferable to surface-treat the type titanyl phthalocyanine composition with a surface-treating agent.

As the surface treatment agent, various conventionally known ones can be used. For example, titanium coupling agents such as isopropyl triisostearoyl titanate, isopropyl tridecyl benzene sulfonyl titanate, tetraisopropyl bis (dioctyl phosphite) titanate and tetraoctyl bis (ditridecyl phosphite) titanate can be used.

However, it is preferable to use a silane coupling agent rather than these titanium coupling agents.

The silane coupling agent is appropriately selected and used depending on the desired stability over time. As silane coupling, vinylsilane such as trichlorovinylsilane, trimethoxyvinylsilane, triethoxyvinylsilane, tri (2-methoxyethoxy) vinylsilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane; acryloxysilane or Methacryloxysilane; aminosilane such as 3-aminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane; 3-chloropropyltrimethoxysilane, trimethoxy-3- Chlorosilane or mercaptosilane such as mercaptopropylsilane; 2
-(3,4-Epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (2,3-epoxypropoxy) propyltrimethoxysilane, 3- (2,3 -Epoxy silanes such as epoxypropoxy) propyltriethoxysilane are exemplified.

Of the above silane coupling agents, epoxy silane coupling agents are preferred.

The amount of surface treatment with the above-mentioned surface treatment agent can be set appropriately. Usually, it is 0.001 to 5% by weight. Preferably
It is 0.01 to 1% by weight.

The treatment with the surface treatment agent is performed by immersing the α-type titanyl phthalocyanine composition in a solution of the surface treatment agent, spraying the solution of the surface treatment agent, and then drying.

Hereinafter, the electrophotographic photoreceptor using the α-type titanyl phthalocyanine composition will be described.

The electrophotographic photoreceptor comprises a conductive base material and a photosensitive layer formed on the conductive base material.

The α-type titanyl phthalocyanine composition is contained in the photosensitive layer. More specifically, the photosensitive layer is a single layer type composed of the α-type titanyl phthalocyanine composition as a charge generating substance, a charge transporting substance, a binder resin and, if necessary, “another material”. It may be a photosensitive layer, or a laminated photosensitive layer in which a charge generating layer containing at least the α-type titanyl phthalocyanine composition and a charge transporting layer containing a charge transporting material and a binder resin are laminated. May be. The laminated photosensitive layer may have a structure in which the charge transport layer is laminated on the charge generation layer or a structure in which the charge transport layer is laminated in the reverse order.

Of the above-mentioned laminated type photosensitive layers, the charge generation layer contains an α-type titanyl phthalocyanine in an amount of 60 to 90% by weight and a metal free phthalocyanine in an amount of 10 to 40% by weight. In addition, it has high sensitivity, small residual potential, and excellent charging property and photosensitivity.

The photoreceptor using the α-type titanyl phthalocyanine composition treated with the silane coupling agent as a charge generating material is particularly excellent in stability when repeatedly used.
Therefore, this photoreceptor can form a high-quality image for a long period of time.

The conductive substrate may have a sheet shape or a drum shape. As the conductive base material, various conductive materials can be used. Metal simple substances such as aluminum, aluminum alloys, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass; metals listed above by means such as vapor deposition; Examples include plastic materials and glass on which layers such as indium oxide and tin oxide are formed.

Since the above α-type titanyl phthalocyanine composition functions as a charge generating material, another charge generating material is not always necessary. However, it is not limited to the oscillation wavelength region of the semiconductor laser, but may be used in combination with another charge generating substance because it is designed to have spectral sensitivity on the short wavelength side. in this case,
Care must be taken not to impair the charging characteristics and photosensitive characteristics of the photoconductor.

Other charge generating materials other than the α-type titanyl phthalocyanine composition include selenium, selenium-tellurium, amorphous silicon, pyrylium salts, azo compounds, disazo compounds, trisazo compounds, anthanthrone compounds, dibenzpyrenequinone. Examples thereof include system compounds, other phthalocyanine compounds, indigo compounds, triphenylmethane compounds, slene compounds, toluidine compounds, pyrazoline compounds, perylene compounds and quinacridone compounds.

These charge generating substances may be used alone or in combination of two or more.

As the charge transport material, an electron-accepting substance having an electron-accepting group such as a nitro group, a nitroso group, and a cyano group, for example,
Fluorenone compounds such as tetracyanoethylene and 2,4,7-trinitro-9-fluorenone; nitrated compounds such as dinitroanthracene and 2,4,8-trinitrothioxanthone; electron-donating substances such as N, N- Diethylaminobenzaldehyde, N, N-diphenylhydrazone, N
-Methyl-3-carbazolylaldehyde, hydrazone compounds such as N, N-diphenylhydrazone; 2,5-di (4-
N, N-Dimethylaminophenyl) -1,3,4-oxadiazole, 2,5-di (4-N, N-diethylaminophenyl)-
Oxadiazole compounds such as 1,3,4-oxadiazole; styryl compounds such as 9- (4-diethylaminostyryl) anthracene; carbazole compounds such as N-ethylcarbazole; 1-phenyl-3- (4 -Dimethylaminophenyl) pyrazolin, 1-phenyl-3- (4-dimethylaminostyryl) -5- (4-dimethylaminophenyl) pyrazolin, 1-phenyl-3- (4-dimethylaminostyryl) -5- (4 -Pyrazoline compounds such as dimethylaminophenyl) pyrazolin; Oxazole compounds such as 2- (4-diethylaminophenyl) -4- (4-dimethylaminophenyl) -5- (2-chlorophenyl) oxazole; Isoxazole compounds; 2-
Thiazole compounds such as (4-diethylaminostyryl) -6-diethylaminobenzothiazole; nitrogen-containing cyclic compounds such as thiadiazole compounds, imidazole compounds, pyrazole compounds, indole compounds, triazole compounds; anthracene, pyrene, phenanthrene Condensed polycyclic compounds such as; poly-N-vinylcarbazole; polyvinylpyrene; polyvinylanthracene; ethylcarbazole-formaldehyde resin.

The charge transport materials may be used alone or in combination of two or more.

The charge transport material according to the fourth invention has an oxidation potential of 0.
Those of 45 to 0.65 eV are used. The reason for this is as follows.

In order to move the charges generated from the charge generating material in the electrophotographic photoreceptor, it is necessary that the charges are injected into the charge transporting material and the injected charges hop between the charge transporting molecules. . Therefore, the energy relationship between the energy of the generated charge and the orbital energy of the charge transporting molecule into which the charge is injected becomes important. And
When the relationship between the two energies is optimal, the efficiency of injecting the generated charges into the charge transport material is improved, and the sensitivity of the photoconductor can be increased. And the charge generation material is α
In the case of the type titanyl phthalocyanine composition, the oxidation potential is 0.
The combination of using a charge transport material of 45 to 0.65 eV gives the most sensitive photoreceptor.

As the charge transport material having an oxidation potential of 0.45 to 0.65 eV, for example, Etc.

The oxidation potential is measured using cyclic voltammetry (reference electrode Ag / Ag ⁺ electrode).

As the binder resin, various kinds can be used.
Styrene polymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic polymer, styrene-acrylic copolymer, ethylene-vinyl acetate copolymer, polychlorination Vinyl, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, acrylic modified urethane resin, epoxy resin, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl butyral resin, poly Examples include ether resins and phenol resins. In addition, a photocurable resin such as epoxy acrylate or urethane acrylate can be used. The photoconductive polymer used as a charge transport material such as poly-N-vinylcarbazole may be used as the binder resin.

As the "other materials", there are conventionally known sensitizers such as terphenyl, halonaphthoquinones and acenaphthylene; 9- (N, N
Examples include various additives such as fluorene compounds such as -diphenylhydrazino) fluorene and 9-carbazolyliminofluorene; plasticizers; antioxidants, deterioration inhibitors such as ultraviolet absorbers, and the like.

The proportions of the α-type titanyl phthalocyanine composition, the charge transporting substance and the binder resin in the single-layer type photosensitive layer can be appropriately selected according to the desired characteristics of the photoreceptor. The α-type titanyl phthalocyanine composition is used in an amount of 2 to 25 parts by weight, preferably 3 to 15 parts by weight, and the charge transport material is 25 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the binder resin.
Used by weight. When the α-type titanyl phthalocyanine composition and the charge transport substance are less than the lower limit amount used,
Not only is the sensitivity of the photoconductor insufficient, but the residual potential becomes large. If the above upper limit is exceeded, the surface potential of the photoconductor will be lowered. The thickness of the single-layer type photosensitive layer is preferably 3 to 50 μm, particularly preferably 5 to 20 μm.

The charge generation layer of the laminated photosensitive layer is formed by vapor deposition and sputtering of the α-type titanyl phthalocyanine composition at a temperature of 200 ° C. or lower while suppressing the crystal structure transition. In this formation, it is preferable to use a binder resin in order to improve the productivity without changing the crystal structure.

When the charge generation layer in the laminated photosensitive layer is formed by using the binder resin, the ratio of the α-type titanyl phthalocyanine composition and the binder resin can be appropriately set. Binder resin 10
Α-type titanyl phthalocyanine composition 5 relative to 0 part by weight
It is preferable to use ˜5000 parts by weight, particularly preferably 10 to 2500 parts by weight. When the amount of the α-type titanyl phthalocyanine composition is less than 5 parts by weight, the charge generation ability is small, and
If it exceeds 00 parts by weight, there is a problem that the adhesion of the photosensitive layer to the conductive substrate is lowered. The thickness of the charge generation layer is 0.01
-30 μm is preferable, and 0.1-20 μm is particularly preferable.

When the charge transport layer of the laminated photosensitive layer is formed, the ratio of the charge transport material and the binder resin is preferably 10 to 500 parts by weight, particularly 25 to 2 parts by weight with respect to 100 parts by weight of the binder resin.
It is preferable to use 00 parts by weight. This is because when the charge transport material is less than 10 parts by weight, the charge transport ability is insufficient, and
This is because if the amount exceeds 0 parts by weight, the mechanical strength and the like of the charge transport layer will decrease.

The thickness of the charge transport layer is preferably 2 to 100 μm, and 5 to 30 μm.
About μm is particularly preferable.

The single-layer type photosensitive layer is prepared by preparing a photosensitive layer dispersion containing an α-type titanyl phthalocyanine composition, a charge transport material, a binder resin, etc., and coating the photosensitive layer dispersion on a conductive substrate, It can be formed by drying.

The laminate type photosensitive layer comprises a charge generation layer dispersion containing an α-type titanyl phthalocyanine composition and a binder resin, and a charge transport layer coating solution containing a charge transport substance and a binder resin. It can be formed by adjusting, sequentially applying to a conductive base material, and drying.

When preparing the dispersion liquid and the coating liquid (hereinafter referred to as “dispersion liquid”), an appropriate organic solvent is used depending on the kind of the binder resin and the like. The organic solvent used is methanol,
Alcohols such as ethanol, propanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene and the like Halogenated hydrocarbons; dimethyl ether, diethyl ether,
Examples include ethers such as tetrahydrofuran, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformamide; dimethyl sulfoxide. These organic solvents may be used alone or in combination of two or more.

The dispersion or the like contains a surfactant in order to improve the dispersibility, coatability, etc. of the α-type titanyl phthalocyanine composition;
It may contain a leveling agent such as silicone oil.

The dispersion liquid and the like can be prepared by using a conventionally used mixing and dispersing method, for example, a mixer, a ball mill, a paint shaker, a sand mill, an attritor, an ultrasonic disperser or the like. For the application of the dispersion liquid or the like, a conventionally used coating method such as dip coating, spray coating, spin coating, roller coating, blade coating, curtain coating or bar coating is used.

An electrophotographic photoreceptor is obtained by applying the dispersion liquid or the like to a conductive substrate and then drying it.

The drying conditions can be appropriately set depending on the type of the solvent used. In order to prevent deterioration of the charge transport material, it is usually carried out at a temperature of 50 to 300 ° C. for 30 minutes to 24 hours.

An undercoat layer may be formed between the conductive base material and the photosensitive layer in order to enhance the adhesion between the conductive base material and the photosensitive layer. The undercoat layer has a thickness of about 0.01 to 1 μm after drying,
It is formed by applying a solution containing a natural or synthetic polymer.

In order to protect the photosensitive layer, a surface protective layer may be formed on the photosensitive layer. The surface protective layer is usually made of various binder resins; a mixed solution of the binder resin and additives such as an anti-deterioration agent, etc., so that the film thickness after drying is preferably about 0.1 to 10 μm, preferably 0.2 to 5 μm.
It is formed by coating so as to have a thickness of about μm.

Since the photosensitive layer of the electrophotographic photosensitive member contains the α-type titanyl phthalocyanine composition, it is excellent not only in electrical characteristics such as charging property, dark decay and residual potential but also in sensitivity. Therefore, the electrophotographic photoconductor is useful not only as a laser beam printer but also as an organic photoconductor used in an image forming apparatus such as a copying machine or a facsimile.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples.

Synthetic Example 1 4 mol of 1,3-diiminoisoindolenin, 1 mol of diisopropoxybis (1-acetyl, 2-propoxy) titanium, and a predetermined amount of alkylbenzene were charged into a reaction vessel, and the mixture was heated at 170 to 180 ° C. By reacting at temperature for 5 hours,
Titanyl phthalocyanine was synthesized.

Synthesis Example 2 Titanyl phthalocyanine was prepared by charging 4 mol of 1,3-diiminoisoindolenin, 1 mol of tetrabutoxytitanium and a predetermined amount of quinoline into a reaction vessel and reacting them at a temperature of 170 to 180 ° C. for 5 hours. Was synthesized.

Example 1 Titanyl phthalocyanine synthesized in Synthesis Example 1 above
1500 parts by weight of concentrated sulfuric acid having a concentration of 98% was added to 100 parts by weight to dissolve the solution, and the mixture was allowed to stand at a temperature of 25 ° C. for 3 hours. A type titanyl phthalocyanine composition was deposited. Next, the α-type titanyl phthalocyanine composition was separated by filtration, dispersed in dichloromethane and washed.

The above-mentioned filtration and washing were repeated and dried at a temperature of 80 ° C. to obtain an α-type titanyl phthalocyanine composition.

The obtained α-type titanyl phthalocyanine composition and a predetermined amount of dichloromethane were charged in a ball mill and mixed for 20 hours to produce an α-type titanyl phthalocyanine composition.

The produced α-type titanyl phthalocyanine composition contained about 82.3% by weight of α-type titanyl phthalocyanine.

FIG. 2A shows an X-ray diffraction spectrum of the obtained α-type titanyl phthalocyanine composition.

Α-type titanyl phthalocyanine composition obtained in Example 1
100 parts by weight, 100 parts by weight of vinyl chloride-vinyl acetate copolymer (Sekisui Chemical Co., Ltd., trade name "Eslec C"), 300 parts by weight of dichloromethane and 200 parts by weight of tetrahydrofuran are dispersed and mixed using ultrasonic waves to generate an electric charge. A layer dispersion was prepared.

In addition, 70 parts by weight of 4-diethylaminobenzaldehyde N, N-diphenylhydrazone, bisphenol Z type polycarbonate (manufactured by Mitsubishi Gas Chemical Co., Inc., trade name "Z-300") 1
A charge transport layer solution was prepared using 00 parts by weight and 500 parts by weight of benzene.

Next, the charge generation layer dispersion liquid is applied to an aluminum sheet and dried at 100 ° C. for 1 hour to form a charge generation layer having a thickness of 1 μm or less, and then the charge generation layer is charged with the charge. A transport layer solution was applied and dried at a temperature of 100 ° C. for 1 hour to form a charge transport layer having a film thickness of about 15 μm on the charge generation layer to prepare an electrophotographic photoreceptor.

Comparative Examples 1 to 3 and Examples 2 to 6 A predetermined amount of metal-free phthalocyanine was added to the α-type titanyl phthalocyanine composition synthesized in the above Synthesis Example 1, and the content of the α-type titanyl phthalocyanine was smaller than that in the Synthesis Example 1. An α-type titanyl phthalocyanine composition was produced (Comparative Examples 1 to 3 and Examples 2 to 5).

Further, an α-type titanyl phthalocyanine composition containing 88.1% of α-type titanyl phthalocyanine was produced in the same manner as in Example 1 except that the titanyl phthalocyanine of Synthesis Example 2 was used (Example 6).

As described above, eight kinds of α-type titanyl phthalocyanine compositions having different contents of α-type titanyl phthalocyanine were produced.

Then, in the same manner as in Example 1, an electrophotographic photosensitive member was produced.

The electrostatic characteristics and photosensitivity characteristics of the electrophotographic photoconductors produced in Examples 1 to 6 and Comparative Examples 1 to 3 were measured by an electrostatic copying tester (trade name “Juntech” manufactured by Juntec Co., Ltd.).
Cynthia 30M ") to negatively charge the electrophotographic photoconductor by performing corona discharge under the condition of -6.0KV, and the surface potential Vs.p. (V) and flow-in of each electrophotographic photoconductor The current Ip (μA) was measured.

Further, using a semiconductor laser light having a wavelength of 780 nm, the electrophotographic photosensitive member is exposed to light, and the time until the surface potential Vs.p. is reduced to 1/2 is obtained, and the half-exposure amount E1 / 2 (μJ / cm ² ) is calculated, and the surface potential after exposure for 0.15 seconds is calculated as the residual potential.
It was determined as Vr.p. (V).

Table 1 shows the test results of the charging characteristics and the photosensitive characteristics of the electrophotographic photosensitive members obtained in the examples and the comparative examples. FIG. 1 shows the relationship between the α-type titanyl phthalocyanine content in the α-type titanyl phthalocyanine composition and the half-exposure amount which is an index of sensitivity.

In the figure, alpha-type titanyl phthalocyanine content of alpha type titanyl phthalocyanine composition, the infrared absorption spectra in alpha type titanyl phthalocyanine specific absorption wave numbers (870 cm ^-1), metal-free phthalocyanine specific absorption wave numbers (890 cm ^-1 ) And a calibration curve was created based on

As is clear from Table 1 and FIG. 1, the photoconductor containing the α-type titanyl phthalocyanine composition containing the α-type titanyl phthalocyanine and the metal-free phthalocyanine is excellent in charging property and has a small residual potential. ,
It was found to be highly sensitive. In particular, a photoreceptor containing an α-type titanyl phthalocyanine composition containing 60 to 90% by weight of α-type titanyl phthalocyanine has a half-exposure amount of 0.6.
It was less than μJ / cm ² , and it was found that the sensitivity was extremely high.

Examples 7 to 10 100 parts by weight of the titanyl phthalocyanine synthesized in Synthesis Example 1 above was dissolved in 1500 parts by weight of concentrated sulfuric acid having a concentration of 98%, and the solution was left at 25 ° C for 3 hours to obtain a concentrated sulfuric acid solution. Then, the resulting concentrated sulfuric acid solution was treated at -5 ° C (Example 7) and 18 ° C.
(Example 8), 40 ° C (Example 9) or 70 ° C (Example 10)
The α-type titanyl phthalocyanine composition was deposited by injecting each into a large amount of water.

Then, using each α-type titanyl phthalocyanine composition obtained as described above, four kinds of electrophotographic photoreceptors were prepared in the same manner as in Example 1, and Comparative Examples 1 to 3 and Example 2 The characteristics of the photoconductor were examined in the same manner as in No. 6. Table 2 shows
The results are shown below.

For reference, Example 1 in which a concentrated sulfuric acid solution containing an α-type titanyl phthalocyanine composition was injected into water at 0 ° C.
The data obtained in Table 1 are also shown in the table.

As is clear from Table 2 above, the electrophotographic photoreceptors of Examples 7 to 10, in particular, Examples 7 to 10 in which a concentrated sulfuric acid solution of the α-type titanyl phthalocyanine composition was poured into water at a temperature of -5 to 40 ° C.
It was found that each of the electrophotographic photoconductors of 9 has excellent charging characteristics and sensitivity characteristics.

Examples 11 to 16 Instead of the concentrated sulfuric acid having a concentration of 98% used in Example 1, a concentration of 82% was used.
(Example 11), 90% concentration (Example 12), 94% concentration (Example 13), 96% concentration (Example 14), 100% concentration (Example 1)
5) and concentrated sulfuric acid having a concentration of 105% (Example 16) were used, and an α-type titanyl phthalocyanine composition was produced in the same manner as in Example 1 using the titanyl phthalocyanine composition synthesized in the Synthesis Example.

Then, an electrophotographic photoreceptor was prepared in the same manner as in Example 1, and the charging characteristics and the photosensitive characteristics of each photoreceptor were examined in the same manner as in Examples 1 to 6. Table 3 shows the results.

As is clear from Table 3 above, Examples 11 to 16, among others,
It was found that the electrophotographic photoreceptors of Examples 13 to 16 using sulfuric acid having a concentration of 94 to 105% were excellent in charging characteristics and photosensitive characteristics.

Example 17 Titanyl phthalocyanine 100 synthesized in Synthesis Example 1
Parts by weight, except that dissolved in 6000 parts by weight of concentrated sulfuric acid having a concentration of 98%, in the same manner as in Examples 14 to 19, to prepare an α-type titanyl phthalocyanine composition, then to prepare an electrophotographic photoreceptor. . The characteristics of the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 1 above. Table 4 shows the results. The table also shows the characteristics of the electrophotographic photosensitive member produced in Example 1.

As shown in Table 4 above, it was found that the electrophotographic photosensitive member of Example 17 also showed good characteristics, but the charging characteristics were relatively low.

Example 18 The α-type titanyl phthalocyanine composition obtained in Example 6 was used as an epoxysilane-based silane coupling agent
It was treated with (3,4-epoxycyclohexyl) ethyltrimethoxysilane to prepare an α-type titanyl phthalocyanine composition having a treatment amount of about 0.03% by weight.

Using the obtained α-type titanyl phthalocyanine composition, an electrophotographic photoreceptor was prepared in the same manner as in Example 1.

The initial characteristics of the produced electrophotographic photosensitive member and the characteristics after 200 cycles of charging and exposure were evaluated in the same manner as in Example 1 above, and the results shown in Table 5 were obtained.

The table also shows the characteristics of the electrophotographic photoconductor of Example 6.

As shown in Table 5 above, the electrophotographic photoreceptor of Example 18 using the α-type titanyl phthalocyanine composition treated with the silane coupling agent has excellent repetitive characteristics and shows stable charging characteristics and photosensitive characteristics. It has been found.

Example 19 A predetermined amount of metal-free phthalocyanine was added to the titanyl phthalocyanine synthesized in Synthesis Example 1, and a concentrated sulfuric acid solution containing titanyl phthalocyanine was poured into water at 0 ° C. in the same manner as in Example 1 to obtain sulfuric acid. A purified α-type titanyl phthalocyanine composition was prepared. Then this α
The titanyl phthalocyanine composition was immersed in cyclohexanone for 5 hours to prepare an α titanyl phthalocyanine composition containing 76.3% by weight of α titanyl phthalocyanine.

Using the α-type titanyl phthalocyanine composition thus obtained, an electrophotographic photoreceptor was prepared in the same manner as in Example 1 above.

Examples 20 and 21 The sulfuric acid-purified α-type titanyl phthalocyanine composition obtained in Example 19 was placed in dichloromethane for 5 hours (Example 20).
Then, it was immersed for 1 week (Example 21) to prepare an α-type titanyl phthalocyanine composition.

Then, using each of the obtained α-type titanyl phthalocyanine compositions, an electrophotographic photoreceptor was prepared in the same manner as in Example 1.

Example 22 The sulfuric acid-purified α-type titanyl phthalocyanine composition obtained in Example 19 was mixed and dispersed in a ball mill for 24 hours in the presence of dichloromethane to prepare an α-type titanyl phthalocyanine composition.

Then, using the obtained α-type titanyl phthalocyanine composition, an electrophotographic photoreceptor was prepared in the same manner as in Example 1.

Comparative Example 4 The β-type titanyl phthalocyanine composition was prepared by mixing and dispersing the sulfuric acid-purified α-type titanyl phthalocyanine composition obtained in Example 22 in a ball mill for 24 hours in the presence of toluene.

Then, using the obtained β-type titanyl phthalocyanine composition, an electrophotographic photoreceptor was prepared in the same manner as in Example 1.

The characteristics of the electrophotographic photoreceptors of Examples 19 to 22 and Comparative Example 4 were evaluated in the same manner as in Example 1 above, and the results shown in Table 6 below were obtained.

As is clear from Table 6 above, the electrophotographic photoconductors of Examples 19 to 22 are excellent in charging property and photosensitivity property even if β-type titanyl phthalocyanine is partially mixed. In particular, the electrophotographic photoreceptor of Example 22 ball-milled in the presence of dichloromethane was found to have a particularly high sensitivity. On the other hand, the electrophotographic photosensitive member of Comparative Example 4 using β-type titanyl phthalocyanine has a high residual potential and is not sufficiently sensitive.

The X-ray diffraction spectra of the titanyl phthalocyanines of Examples 19, 21, 22 and Comparative Example 4 are shown in FIGS. 2B, C, D and E, respectively.

As is clear from the figure, the α-type titanyl phthalocyanine composition (B) soaked in cyclohexanone undergoes crystallization, and the β-type titanyl phthalocyanine partially mixed in the solution soaked in dichloromethane (C). On the contrary,
In the case of ball milling (D) in the presence of dichloromethane, a diffraction peak clearly appeared, and it was confirmed to be α-type titanyl phthalocyanine. Further, ball milling of the α-type titanyl phthalocyanine composition in the presence of toluene (E) showed β-type crystals.

Examples 23 and 24, Comparative Examples 5 and 6 To 100 parts by weight of the titanyl phthalocyanine obtained in Synthesis Example 2,
1500 parts by weight of concentrated sulfuric acid having a concentration of 98% was melted and left at a temperature of 25 ° C. for 3 hours. Then, the obtained solution was poured into a large amount of water at 0 ° C. to obtain a slurry containing the α-type titanyl phthalocyanine composition. The α-type titanyl phthalocyanine composition was filtered off from the obtained slurry. Then, it was dispersed in the filtered off dichloromethane and washed. Then, filtration and washing were repeated several times and dried at a temperature of 80 ° C. to obtain an α-type titanyl phthalocyanine composition.

The obtained α-type titanyl phthalocyanine composition and a predetermined amount of dichloromethane were charged in a ball mill and mixed for 20 hours to obtain an α-type titanyl phthalocyanine composition.

The obtained α-type titanyl phthalocyanine composition contained about 82.3% by weight of α-type titanyl phthalocyanine.

Ultrasonic dispersion was performed using 8 parts by weight of the α-type titanyl phthalocyanine composition having the above composition, 100 parts by weight of bisphenol Z-type polycarbonate (manufactured by Mitsubishi Gas Chemical Co., Inc.), 100 parts by weight of the charge transport material shown in Table 7 and 1000 parts by weight of tetrahydrofuran. The dispersion was prepared in a container and applied on an aluminum sheet to prepare an electrophotographic photoreceptor having a photosensitive layer having a thickness of about 20 μm.

The electrophotographic photoconductors obtained in Examples 23 and 24 and Comparative Examples 5 and 6 were positively charged by using an electrostatic copying tester (Gentec Cynthia 30M manufactured by Gentec Co., Ltd.) to obtain a surface potential V.
sp (V) was measured.

Also, by exposing the photoconductor using halogen light, the time until the surface potential becomes half the initial value is obtained, and the half-exposure amount E
1/2 (μJ / cm ² ) was calculated, and the surface potential after 0.15 seconds after exposure was determined as the residual potential Vrp (V).

The oxidation potential of each charge transport material shown in Table 7 above was measured by cyclic voltammetry. In this measurement, a platinum electrode was used as a working electrode, 0.1 mol of acetonitrile Ag / Ag ⁺ electrode was used as a reference electrode, and a platinum electrode was used as a counter electrode. A dichloromethane solution containing 1 mmol of each charge-transporting material and 0.1 mol of a supporting electrolyte (nC ₄ H ₉ ) ₄ NClO ₄ was bubbled with argon gas, and then the scanning speed was 10%.
It was measured at 0 mV / sec. Table 8 below shows the measurement results of the half-exposure amount and residual potential of each electrophotographic photosensitive member.

As is clear from Table 8 above, the electrophotographic photoreceptors of Examples 23 and 24 were found to have not only a lower residual potential than the electrophotographic photoreceptors of Comparative Examples 5 and 6 but also high sensitivity. . As described above, the electrophotographic photoreceptor containing the charge transport material having an oxidation potential of 0.45 to 0.65 eV has excellent sensitivity and low residual potential.

<Effects of the Invention> As described above, the α-type titanyl phthalocyanine composition according to claim 1 contains the metal-free phthalocyanine and α.
By containing the type titanyl phthalocyanine in a predetermined ratio, there is an effect that the absorption wavelength region is wide and the spectral sensitivity is large even though the metal-free phthalocyanine which is an unstable crystal type is contained.

According to the method for producing an α-type titanyl phthalocyanine composition according to claim 2, since the acid paste method of injecting a concentrated sulfuric acid solution containing at least titanyl phthalocyanine into water is used for pigmentation, wet milling is performed with a chlorine-based solvent. The effect is that an α-type titanyl phthalocyanine composition that is stable over time can be easily produced.

The electrophotographic photoreceptor according to claim 3 contains metal-free phthalocyanine and α-type titanyl phthalocyanine in a predetermined ratio in the photosensitive layer, and therefore has excellent charging property, small dark decay, high sensitivity, and residual potential. Has the effect of being small.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the α-type titanyl phthalocyanine content in the α-type titanyl phthalocyanine compositions and the sensitivity in Examples 1 to 6 and Comparative Examples 1 to 3. FIG. 2 shows an X-ray diffraction spectrum. Of these, FIG. A is an X-ray diffraction spectrum of the α-type titanyl phthalocyanine composition obtained by the sulfuric acid refining method. FIG. 6B is an X-ray diffraction spectrum of the α-type titanyl phthalocyanine composition obtained by immersing the α-type titanyl phthalocyanine composition obtained by the sulfuric acid refining method in cyclohexanone. FIG. 13C is an X-ray diffraction spectrum of the α-type titanyl phthalocyanine composition obtained by immersing the α-type titanyl phthalocyanine composition obtained by the sulfuric acid refining method in dichloromethane. Figure D
2 is an X-ray diffraction spectrum of the α-type titanyl phthalocyanine composition obtained by ball milling the α-type titanyl phthalocyanine composition obtained by the sulfuric acid refining method in the presence of dichloromethane. Fig. E shows α obtained by the sulfuric acid purification method.
Type titanyl phthalocyanine composition in the presence of toluene,
3 is an X-ray diffraction spectrum of the α-type titanyl phthalocyanine composition after ball milling.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-61-239248 (JP, A) JP-A-62-194257 (JP, A) JP-A-62-275272 (JP, A)

Claims (3)

[Claims] 1. A formula: And 1,3-diiminoisoindolenine represented by the general formula: Ti (R ¹ ) ₂ (R ² ) ₂ (wherein R ¹ and R ² are the same or different and represent a lower alkoxy group) In the concentrated sulfuric acid solution of titanyl phthalocyanine obtained by reacting with an organotitanium compound represented by or a concentrated sulfuric acid solution obtained by adding metal-free phthalocyanine to the titanyl phthalocyanine is pigmented by the acid paste method into water, α-type Titanyl phthalocyanine 60-90% by weight and metal-free phthalocyanine 10-40
An α-type titanyl phthalocyanine composition, characterized in that the α-type titanyl phthalocyanine composition is contained. 2. The formula: And 1,3-diiminoisoindolenine represented by the general formula: Ti (R ¹ ) ₂ (R ² ) ₂ (wherein R ¹ and R ² are the same or different and represent a lower alkoxy group) In order to obtain a titanyl phthalocyanine by reacting with an organotitanium compound represented by the following, if necessary, a metal free phthalocyanine is added thereto, the titanyl phthalocyanine alone or a concentrated sulfuric acid solution containing the titanyl phthalocyanine and the metal free phthalocyanine in water. Α-type titanyl phthalocyanine 60-90% by weight and metal-free phthalocyanine 10-40% by weight, which are characterized in that they are pigmented by the acid paste method of injecting into the mixture, and then wet milled in the presence of a chlorine-based solvent. Method for producing type titanyl phthalocyanine composition. 3. The formula: And 1,3-diiminoisoindolenine represented by the general formula: Ti (R ¹ ) ₂ (R ² ) ₂ (wherein R ¹ and R ² are the same or different and represent a lower alkoxy group) In the concentrated sulfuric acid solution of titanyl phthalocyanine obtained by reacting with an organotitanium compound represented by or a concentrated sulfuric acid solution obtained by adding metal-free phthalocyanine to the titanyl phthalocyanine is pigmented by the acid paste method into water, α-type Titanyl phthalocyanine 60-90% by weight and metal-free phthalocyanine 10-40
An electrophotographic photoreceptor having a photosensitive layer containing 1% by weight formed on a conductive substrate.