JPH107925A - Preparation of oxytitanium phthalocyanine and electrophotographic photoreceptor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for preparing an oxytitanium phthalocyanine which can easily prepare an oxytitanium phthalocyanine as an excellent charge generating agent for an electrophotographic photoreceptor by converting a dihalogenotitanium phthalocyanine to TiOPc by a specified method and suspending the TiOPc in an org. solvent. SOLUTION: This process for preparing an oxytitanium phthalocyanine comprises the steps of: bringing a dihalogenotitanium phthalocyanine into contact with a mixed solvent composed of an N-alkyllactam compd. and water to prepare an oxytitanium phthalocyanine; and bringing the oxytitanium phthalocyanine into contact with a hydrophobic solvent. The hydrophobic solvent is pref. toluene. Further pref., the mixed solvent contains 1 to 50wt.% water. Still pref., the dihalogenotitanium phthalocyanine is brought into contact with the mixed solvent in the presence of a deoxygenating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for obtaining oxytitanium phthalocyanine having excellent electric characteristics when used in an electrophotographic photosensitive member, and to an electrophotographic photosensitive member using this oxytitanium phthalocyanine.

[0002]

BACKGROUND OF THE INVENTION Since the discovery of phthalocyanine compounds having good photoconductivity, many studies have been made on photoelectric conversion materials such as electrophotographic photosensitive members, solar cells and sensors. In recent years, research and development of laser beam printers using laser light as a light source instead of the conventional white light and having advantages of high speed, high image quality and non-impact have been actively conducted. Have been done. Particularly, the recent development of semiconductor lasers has been remarkable, and it has become possible to reduce the price of a small and stable laser oscillator, and it is being used as a light source for electrophotography. The wavelength of such a semiconductor laser light source is 800
Therefore, a photoreceptor having high sensitivity to a long wavelength region of about 800 nm is strongly desired. Squaric acid, methine dyes, cyanine dyes, pyrylium dyes, thiapyrylium dyes, polyazo dyes, phthalocyanine dyes, and the like are known as organic photoconductive materials that satisfy this requirement. Of these, squaric acid, methine dyes, cyanine dyes, pyrylium dyes, and thiapyrylium dyes are relatively easy to increase the wavelength of spectral sensitivity but lack practical stability such as repeated use. In addition, polyazo dyes have difficulty in increasing the absorption wavelength and have difficulty in production. On the other hand, phthalocyanine dyes have an absorption peak in the wavelength region of 600 nm or more, and the absorption wavelength is extended to a relatively longer wavelength region than other dyes. Has been widely studied.

[0003] Phthalocyanines not only have different absorption spectra and photoconductivity depending on the type of central metal, but also have different physical properties depending on the crystal type. Some examples have been reported in which is selected as an electrophotographic photosensitive member. For example, oxytitanium phthalocyanine (hereinafter referred to as “TiOP
c)), there are various crystal forms, and it is reported that there are large differences in chargeability, dark decay, sensitivity, etc. due to the difference of the crystal forms. In JP-A-59-49544, the crystal form of TiOPc is a Bragg angle (2θ ±
0.2 °) = 9.2 °, 13.1 °, 20.7 °, 2
Those which give a strong diffraction peak at 6.2 ° and 27.1 ° are described as suitable, and the X-ray diffraction spectrum is shown. JP-A-3-50270 discloses dichlorotitanium phthalocyanine (hereinafter referred to as “Ti
Cl ₂ Pc) or dibromotitanium phthalocyanine (hereinafter referred to as “TiBr ₂ Pc”) by contact with an organic solvent other than hydrocarbons, ethers, esters, alcohols, phenols, and naphthols. It is stated that TiOPc having a specific crystal form can be selectively produced. In addition, JP-A-62-2568
Various crystal forms and production methods are known as disclosed in JP-A-65-256, JP-A-62-256867, JP-A-63-366, JP-A-61-217050 and the like. .

However, since phthalocyanines have a high reaction temperature of 200 to 300 ° C. during the synthesis, impurities are easily produced as by-products, and the solubility in a solvent is extremely small, so that it is difficult to purify the phthalocyanines with high purity. When phthalocyanines are used for an electrophotographic photoreceptor, even a very small amount of impurities can easily affect electrical properties such as charging potential, sensitivity, residual potential, and potential stability during repeated use. It is necessary to remove unnecessary impurities as much as possible.

[0005] As a method of purifying phthalocyanines, recrystallization with sulfuric acid, Soxhlet extraction with acetone or an organic solvent, or sublimation purification are known. Recrystallization with sulfuric acid is to precipitate crystals by diluting a sulfuric acid solution of phthalocyanines with water.At the time of crystal precipitation, there is a possibility that impurities may be adsorbed again, depending on the type of metal phthalocyanine, Since the demetalization reaction occurs, it is not common, and there are problems such as the remaining sulfuric acid adversely affecting the electrical characteristics. Methods such as recrystallization with an organic solvent or Soxhlet extraction do not show a sufficient effect for an electrophotographic photosensitive member because the solubility of phthalocyanines is extremely small. In addition, sublimation purification is the most excellent method for purifying phthalocyanines. For this reason, especially when the phthalocyanine is used as an electrophotographic photoreceptor having a charge generation layer, the charge generation layer is often formed by depositing the phthalocyanine for purification. However, even in the case of vapor deposition, it is not always possible to remove all impurities, and it is not suitable for mass production.

[0006] Heat suspension treatment with a high-boiling organic solvent is also known as a purification method, but it can be produced on an industrial scale and is extremely useful. However, in the known thermal suspension treatment, since the treatment is performed at a high temperature in order to remove impurities, phthalocyanines are decomposed conversely, and decomposed products remain as impurities. Was. For example, in Japanese Patent Application Laid-Open No. 61-171771,
It has been shown that TiOPc heat-suspended at 150 to 170 ° C. using 1-methylpyrrolidone is useful as a charge generating agent for an electrophotographic photoreceptor. It is difficult to control the temperature at which it is not used, and when this TiOPc is used for an electrophotographic photoreceptor, there are problems such as a large potential change during repeated use or a large change in characteristics due to the environment. Did not.

[0007]

As described above, the present inventors focused on the suspension treatment with an organic solvent which is advantageous for production on an industrial scale, and studied how to treat TiOPc with an organic solvent. The study was conducted from the viewpoint of whether it can be used as an excellent charge generating agent for an electrophotographic photosensitive member.

[0008]

As a result, an excellent dihalogenotitanium phthalocyanine (hereinafter referred to as "TiX ₂ Pc") is converted into TiOPc by a specific method, and this TiOPc is subjected to suspension treatment with an organic solvent. The present inventors have found a method for obtaining a charge generating agent for an electrophotographic photoreceptor extremely easily, and have reached the present invention.

That is, the first gist of the present invention is that TiX ₂ P
c is brought into contact with a mixed solvent of N-alkyl lactams and water in the presence of a deoxidizing agent to form TiOPc, and the TiOPc is contacted with a hydrophobic solvent. Further, a second gist of the present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive support,
An electrophotographic photoreceptor characterized in that the photosensitive layer contains the TiOPc.

However, with this configuration, β-type Ti as a charge generating agent for an electrophotographic photoreceptor can be extremely easily formed.
OPc can be easily obtained. Furthermore, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer contains the β-type TiOPc obtained as described above, so that the photosensitive layer has high sensitivity in a long wavelength region around 800 nm. The object of providing an electrophotographic photosensitive member having excellent durability is also achieved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
TiOPc according to the present invention is represented by the following general formula [1], and has a Bragg angle (2θ ± 0.2 °) of 9.3 ° in a powder X-ray diffraction spectrum using CuKα radiation.
10.6 °, 13.2 °, 15.2 °, 20.8 °, 2
An object of the present invention is to obtain β-type TiOPc showing a main diffraction peak at 6.3 °.

[0012]

Embedded image

(Wherein X represents a halogen atom, and n represents 0)
Represents a number from to 1. The TiOPc according to the present invention can be synthesized by a known method, for example, can be synthesized from orthophthalodinitrile and a titanium compound. That is, orthophthalodinitrile and a halide of titanium are heated and reacted in an inert solvent. As the titanium compound, titanium tetrachloride, titanium trichloride, titanium tetrabromide and the like can be used, but titanium tetrachloride is preferable in terms of cost. As the inert solvent, trichlorobenzene, α-chloronaphthalene, β-chloronaphthalene, methylnaphthalene, methoxynaphthalene, diphenyl ether, diphenylmethane, diphenylethane,
High boiling organic solvents which are inert to the reaction, such as ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, and triethylene glycol dialkyl ether, are preferred. The reaction temperature is usually 150 to 300 ° C, especially
80-250 ° C is preferred.

Since TiX ₂ Pc is produced by the reaction, it is filtered off and washed with the solvent used in the reaction to remove impurities produced during the reaction and unreacted components. Next, methanol,
The solvent used in the reaction is removed by washing with an inert solvent such as alcohols such as ethanol and isopropyl alcohol, and ethers such as tetrahydrofuran and diethyl ether.

Next, the obtained TiX ₂ Pc is brought into contact with a mixed solvent of N-alkyl lactams and water to obtain TiOPc. This TiOPc is usually in a β-type crystal form. N-alkyl lactams include N-
Methylpyrrolidone, 1,3-dimethyl-2-imidazolidin and the like can be mentioned. The mixing ratio of these solvents and water is such that water is 1 to 50% by weight, especially 1
The content of the N-alkyl lactam is preferably 50 to 99% by weight, particularly preferably 70 to 99% by weight based on the whole solvent.

It is preferable that a deoxidizing agent is present during the contact. As the deoxidizing agent, any compound can be used as long as it is a basic compound. For example, γ-picoline, triethylamine, NaOH, KOH, Na ₂
CO ₃ , CH ₃ COONa, ammonia and the like. The amount of these deoxidizing agents is preferably 0.1 to 15 mol, particularly preferably 1 to 8 mol, per 1 mol of TiX ₂ Pc.

The temperature at which the mixed solvent is brought into contact with TiX ₂ Pc can be arbitrarily selected.
~ 150 ° C is preferred. The contact time between TiX ₂ Pc and the mixed solvent depends on the mixing ratio and the contact temperature between the type of N-alkyllactams and water, and the type and amount of deoxidizing agent used when used. ~ 150 ° C
In this case, 1 to 3 hours are effective.

There is no particular limitation on the ratio of TiX ₂ Pc to the mixed solvent used, but a weight ratio of 1: 5 to 100 is preferable in consideration of contact efficiency, operability and the like. If the amount of the mixed solvent is too low, the contact efficiency becomes poor, and the production rate of TiOPc decreases. The method of contacting TiX ₂ Pc with the mixed solvent in the presence of the deoxidizing agent is not particularly limited, but a method of contacting and mixing both in a stirring tank is preferable. In addition, a method in which a mixed solvent containing a deoxidizing agent is passed through a column filled with TiX ₂ Pc can also be adopted. In short, any method may be used as long as the two are brought into contact in the presence of the deoxidizing agent.

After the treatment, the mixture is washed with an inert solvent such as alcohols such as methanol, ethanol and isopropyl alcohol, and ethers such as tetrahydrofuran and diethyl ether, and mixed solvent used in the reaction. Is removed. In the present invention, the thus obtained crude TiOPc is treated with a hydrophobic solvent, usually a hydrophobic organic solvent. Examples of the hydrophobic solvent include benzene, toluene, xylene, nitrobenzene and the like. Particularly, toluene is preferable.

The temperature at which the crude TiOPc is brought into contact with the hydrophobic solvent can be arbitrarily selected.
0-150 ° C is preferred. The contact time between the crude TiOPc and the hydrophobic solvent is determined by the type of the solvent and the contact temperature. In general, when the temperature is 90 to 150 ° C., the effective time is 1 to 3 hours. Although there is no particular limitation on the usage ratio of the crude TiOPc and the hydrophobic solvent, the weight ratio is preferably in the range of 1: 5 to 100 in consideration of contact efficiency, operability, and the like. If the use amount of the hydrophobic solvent is too low, the contact efficiency becomes poor and the purified TiOPc
Production speed decreases.

The method of contacting the crude TiOPc with the hydrophobic solvent is not particularly limited, but a method of contacting and mixing both in a stirring tank is preferable. Further, a method of flowing a hydrophobic solvent through a column filled with crude TiOPc can also be adopted, but any method may be used as long as the crude TiOPc is brought into contact with the hydrophobic solvent. The purified TiOPc thus obtained is usually β
And other crystalline forms of TiOP recognized in the prior art
Since c is not mixed and has a sufficiently high crystallinity, it can be put to practical use as it is. However, if necessary, water, methanol, acetone, N-methylpyrrolidone, dimethyl sulfoxide, N, N-dimethylformamide, etc. Further purification with a solvent is also possible.

The purified TiOPc crystal has, for example, an excellent function as a photoconductor, and can be applied to an electronic material such as an electrophotographic photosensitive member, a solar cell, a sensor, and a switching element. Hereinafter, an example in which TiOPc of the present invention is applied as a charge generating agent in an electrophotographic photoreceptor will be described.

The TiOPc crystal of the present invention is subjected to dispersion treatment in a dispersion medium, and finally prepared as a coating solution for coating a photosensitive layer in a state of being mixed with a binder resin. Various solvents may be used as the dispersion medium. For example, ethers such as diethyl ether, dimethoxymethane, tetrahydrofuran and 1,2-dimethoxyethane; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; alcohols such as methanol, ethanol and propanol alone. Alternatively, two or more kinds can be used as a mixture.

As the binder resin, polyvinyl butyral,
Vinyl polymers such as polyvinyl acetal, polyester, polycarbonate, polystyrene, polyester carbonate, polysulfone, polyimide, polymethyl methacrylate, polyvinyl chloride, and copolymers thereof, phenoxy, epoxy, silicone resins, and partially cross-linked cured products thereof Can be used alone or in combination of two or more.

As a method for dispersing the TiOPc crystal, a known method such as a ball mill, a sand grind mill, a planetary mill, a roll mill or the like can be used. As a method of mixing the binder resin and the TiOPc particles, for example, a method of simultaneously dispersing the TiOPc particles in the form of a powder or a polymer solution thereof while dispersing the TiOPc particles, or dispersing the dispersion in the polymer solution of the binder resin Any method such as a method of mixing, or conversely, a method of mixing a polymer solution in a dispersion may be used.

Next, the dispersion obtained here may be diluted with various solvents in order to obtain liquid properties suitable for coating. As the solvent, for example, the solvents exemplified as the dispersion medium can be used. Ti
The ratio between OPc and the binder resin is not particularly limited, but generally, the content of TiOPc is 5 to 500 parts per 100 parts by weight of the resin.
Used from parts by weight. In this dispersion, the concentration of TiOPc was 0.1% by weight to 10% by weight.
Is preferably used.

If necessary, a charge transfer agent and another charge generating agent can be contained. Examples of the charge transfer agent include electron-withdrawing substances such as 2,4,7-trinitrofluorenone and tetracyanodimethane, carbazole, indole, imidazole, oxazole, oxadiazole, pyrazoline, and heterocyclic compounds such as thiazole; An electron donating substance such as an aniline derivative, a hydrazone compound, an aromatic amine derivative, a stilbene derivative, or a polymer having a group consisting of these compounds in a main chain or a side chain is exemplified. As the charge generating agent, if it is generally used for electrophotographic photoreceptors, for example, bisazo compounds, trisazo compounds, perylene compounds, perinone compounds, polycyclic quinone compounds, anthraquinone compounds, quinacridone compounds, squaric acid, Examples include methine dyes, cyanine dyes, pyrylium dyes, thiapyrylium dyes, polyazo dyes, and other phthalocyanine dyes. The ratio of the charge transfer agent and the charge generator to the binder resin is in the range of 5 to 500 parts by weight based on 100 parts by weight of the binder resin.

Using the dispersion thus prepared,
A charge generation layer is formed on a conductive support, and a charge transfer layer is laminated thereon to form a photosensitive layer, or a charge transfer layer is formed on a conductive support, and the dispersion liquid is formed thereon. To form a photosensitive layer by using the dispersion to form a photosensitive layer on the conductive support. be able to. When the photosensitive layer is formed by laminating the charge generation layer and the charge transfer layer, the thickness of the charge transfer layer is preferably 0.1 μm to 10 μm, and the thickness of the charge transfer layer is preferably 5 μm to 60 μm. When the photosensitive layer is formed with a single structure including only the charge generation layer, the thickness of the charge generation layer is preferably in the range of 5 μm to 60 μm.

When a charge transfer layer is provided, the materials exemplified as the charge transfer agent can be used as the charge transfer agent. A binder resin is blended with these charge transfer agents as needed. As the binder resin, for example, those exemplified above as the binder resin can be used. In the photosensitive layer, if necessary, an antioxidant,
Various additives such as a sensitizer may be included.

Further, in order to protect these photosensitive layers from external impact, a thin protective layer may be provided on the surface of the photosensitive layer.
As the conductive support on which the photosensitive layer is provided, aluminum,
A metal material such as stainless steel and nickel, and an insulating support such as a polyester film, paper, and glass provided on the surface with a conductive layer such as aluminum, copper, palladium, tin oxide, and indium oxide are used. A well-known barrier layer, which is generally used, may be provided between the conductive support and the photosensitive layer.

Examples of the barrier layer include an anodized aluminum film, an inorganic layer such as aluminum oxide and aluminum hydroxide, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, And the like. The thickness of the barrier layer is 0.
A range of 1 μm to 20 μm is preferable, and a range of 0.1 μm to 10 μm is most effective.

As a method for applying the photosensitive layer, the protective layer and the barrier layer, known methods such as a dipping method, a spray coating method, a spinner coating method and a blade coating method can be used. Such an electrophotographic photoreceptor is a laser beam printer, L
It can be widely applied not only to printers such as ED printers and CRT printers, but also to general electrophotographic machines and other electrophotographic application fields.

[0033]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples and Examples, but the present invention is not limited to the following Production Examples and Examples as long as the gist thereof is not exceeded.

(Production Example of Crude TiOPc) 92.0 g of orthophthalodinitrile and 600 m of methylnaphthalene were placed in a 1 L reaction flask equipped with a thermometer, a stirrer, and a reflux condenser.
l, 20 ml of titanium tetrachloride was added dropwise with stirring.
After dropping, the temperature was raised, reacted at 200 to 220 ° C for 5 hours, allowed to cool, filtered at 130 ° C with hot filtration, washed with 400 ml of methylnaphthalene heated to 120 ° C, then washed and dried with 200 ml of methanol, and dried in blue of TiCl ₂ Pc. 61.3 g of a powder were obtained. Elemental analysis values of the obtained TiCl ₂ Pc are as shown in Table 1 below.

[0035]

TABLE 1 CH N Cl Theoretical% 60.88 2.55 17.75 11.23 Analytical% 60.88 2.56 17.73 11.03

Next, in the same reaction flask as above, the TiCl ₂ Pc wet cake obtained here and 28% as a deoxidizer were added.
34% ammonia water, N-methylpyrrolidone 6
And then heated to 145 ° C. (reflux state) and
After stirring for 100 hours, the mixture was cooled to 100 ° C., filtered, and the obtained cake was washed with methanol and dried to obtain crude β-type TiOPc
34.8 g of a blue powder were obtained. The crude β thus obtained
FIG. 2 shows a powder X-ray diffraction spectrum of the type TiOPc by CuKα radiation.

Example 1 10.0 g of the wet cake of crude β-type TiOPc obtained above and 100 ml of toluene were placed in a 200 ml reaction flask equipped with a thermometer, a stirrer and a reflux condenser.
, And the mixture was heated to reflux and stirred for 2 hours.
The resulting cake was washed with methanol and dried to obtain 9.1 g of purified β-type TiOPc blue powder. CuK of the purified β-type TiOPc thus obtained
FIG. 1 shows an X-ray powder diffraction spectrum by α-rays.

Comparative Example 1 Crude β-type TiOPc was placed in a 200 ml reaction flask equipped with a thermometer, a stirrer, and a reflux condenser.
Wet cake 10.0g and N-methylpyrrolidone 100m
After stirring for 2 hours while heating to reflux, 1
The mixture was cooled to 00 ° C., filtered, and the obtained cake was washed with methanol and then dried to obtain 8.2 g of a purified β-type TiOPc blue powder.
I got The thus obtained purified β-type TiOPc C
FIG. 3 shows a powder X-ray diffraction spectrum by uKα radiation.

Comparative Example 2 46.0 g of orthophthalonitrile and 300 ml of methylnaphthalene were charged into a 500-ml reaction flask equipped with a thermometer, a stirrer, and a reflux condenser, and the temperature was raised with stirring and the temperature was raised to 200 to 220 ° C. Titanium tetrachloride 1
After dropping 0 ml, the mixture was reacted for 5 hours. Thereafter, the mixture was allowed to cool, filtered by heating at 130 ° C., and washed with 200 ml of methylnaphthalene heated to 120 ° C. and then with 100 ml of methanol to obtain a TiCl ₂ Pc blue powder.

Then, in the same reaction flask, the TiCl ₂ Pc wet cake thus obtained was subjected to methanol hot suspension (reflux, 2 hours, hot filtration) and hot water boiling suspension (95 to 10).
0 ° C., 2 hours, hot filtration), N-methylpyrrolidone hot suspension (145-150 ° C., 2 hours, hot filtration), methanol hot suspension (reflux state, 2 hours, hot filtration) After drying, 32.1 g of β-type TiOPc blue powder was obtained. FIG. 4 shows the powder X-ray diffraction spectrum of the thus obtained β-type TiOPc by CuKα radiation.

(Example 2) 10 parts by weight of the purified β-type TiOPc produced in Example 1 was pulverized with 200 parts by weight of 4-methoxy-4-methylpentanone-2 by a sand grind mill for 6 hours, and subjected to atomization and dispersion treatment. went. Next, a dispersion was prepared by mixing 5 parts by weight of polyvinyl butyral (Denka Butyral # 6000C, manufactured by Denki Kagaku Kogyo KK) with a 10% solution of 4-methoxy-4-methylpentanone-2. A charge generation layer was provided on an aluminum vapor-deposited surface of this dispersion liquid on a polyester film so that the film thickness after drying was 0.4 μm by a bar coater. Next, 56 parts by weight of a hydrazone compound shown below was placed on the charge generation layer.

[0042]

Embedded image 14 parts by weight of a hydrazone compound shown below,

[0043]

Embedded image And 1.5 parts by weight of the following cyano compound

[0044]

Embedded image

A solution prepared by dissolving 100 parts by weight of a polycarbonate resin (manufactured by Mitsubishi Chemical Corporation, trade name NOVAREX 7030A) in 1,000 parts by weight of 1,4-dioxane is applied by a film applicator, and the film thickness after drying is applied. Was 17 μm. The photoreceptor thus obtained is referred to as photoreceptor A.

Comparative Example 3 In place of the purified β-type TiOPc used in Example 2, the β-type TiOP produced in Comparative Example 1 was used.
A photoconductor was prepared in the same manner as in Example 2, except that OPc was used. The photoreceptor thus obtained is referred to as photoreceptor B.

Comparative Example 4 In place of the purified β-type TiOPc used in Example 2, the β-type Ti produced in Comparative Example 2 was used.
A photoconductor was prepared in the same manner as in Example 2, except that OPc was used. The photoreceptor thus obtained is referred to as photoreceptor C.

(Evaluation) Each of the obtained photoreceptors was evaluated for the electrostatic potential, the residual potential, and the half-exposure sensitivity as initial electric characteristics by using an electrostatic copying paper tester (Model EPA-81, manufactured by Kawaguchi Electric Works, Ltd.).
00). That is, the photoreceptor is negatively charged by corona discharge with an applied voltage set so that the corona current is 35 μA in a dark place, and after 2 seconds, is continuously exposed to 780 nm monochromatic light (1.0 μW / cm ² ) for 10 seconds. ,
By measuring the decay of the surface potential, the charging potential (potential immediately after charging), the residual potential (potential after exposure for 10 seconds), and the exposure amount required for the surface potential to decrease from −600 V to −300 V ( Sensitivity). Table 2 shows the results.

[0049]

[Table 2]

Next, the photoreceptor A and the comparative photoreceptors B and C were evaluated for the charge exposure repetition potential stability using the above-described electrostatic copying paper test apparatus. That is, a cycle in which the photoconductor is negatively charged by corona discharge with an applied voltage set so that the corona current is 35 μA in a dark place, and white light (400 Lux) is continuously exposed for 3 seconds after 0.5 second is 2000. The repetition was repeated twice, and based on the initial charging potential, the degree of change in the charging value after the repetition of 2000 times was determined as the rate of change of the potential as Vo change rate {(initial potential−potential after repetition)} {initial potential}. Table 3 shows the results.
Shown in

[0051]

[Table 3]

As shown in Tables 2 and 3, photosensitive member A was comparative photosensitive member B
It can be seen that the film has higher sensitivity to 780 nm monochromatic light than C and C, and also has excellent potential stability when repeatedly used. As described in detail above, the photoreceptor of the present invention provides a method for producing β-type TiOPc very easily, and is extremely advantageous for production on an industrial scale. Β-type T obtained by the production method according to the present invention
By applying iOPc to an electrophotographic photoreceptor, 80
An electrophotographic photoreceptor having high sensitivity in a long wavelength region of about 0 nm and having more excellent potential stability upon repeated use can be provided.

[0053]

The present invention provides a method for producing TiOPc which is much simpler than conventional purification methods and on an industrial scale. Furthermore, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer contains TiOPc obtained by the production method according to the present invention, and thus has high sensitivity in a long wavelength region around 800 nm. ,
An electrophotographic photosensitive member having excellent durability can be provided.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction spectrum of the purified β-type TiOPc obtained in Example 1.

FIG. 2 shows crude β-type TiO obtained in a production example of crude TiOPc.
X-ray diffraction spectrum of Pc.

FIG. 3 is an X-ray diffraction spectrum of the purified β-type TiOPc obtained in Comparative Example 1.

FIG. 4 is an X-ray diffraction spectrum of β-type TiOPc obtained in Comparative Example 2.

Claims (6)

[Claims] 1. A process for producing oxytitanium phthalocyanine, comprising contacting dihalogeno-titanium phthalocyanine with a mixed solvent of N-alkyllactams and water to form oxytitanium phthalocyanine, and contacting the oxytitanium phthalocyanine with a hydrophobic solvent. Method. 2. The method according to claim 1, wherein the hydrophobic solvent is toluene. 3. The method according to claim 1, wherein the mixed solvent contains 1 to 50% by weight of water. 4. The method according to claim 1, wherein the contact between the dihalogenotitanium phthalocyanine and the mixed solvent is carried out in the presence of a deoxidizing agent. 5. The method according to claim 1, wherein β-oxytitanium phthalocyanine is obtained by contacting with a hydrophobic solvent. 6. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains the oxytitanium phthalocyanine according to claim 1. Description: