JP3453953B2 - Method for producing oxytitanium phthalocyanine and electrophotographic photoreceptor using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing oxytitanium phthalocyanine (hereinafter abbreviated as "TiOPc") and an electrophotographic photoreceptor using this TiOPc.

[Prior art]

Since it was found that phthalocyanine compounds have good photoconductivity, much research has been conducted as photoelectric conversion materials such as electrophotographic photoreceptors, solar cells and sensors. In recent years, laser beam printers have been actively developed and researched by using laser light as a light source instead of conventional white light, which has advantages of high speed, high image quality and non-impact. In particular, the recent development of semiconductor lasers has been remarkable, and it has become possible to reduce the price of a compact 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
Since it is around nm, there is a strong demand for a photoreceptor having high sensitivity in the long wavelength region around 800 nm. Known organic photoconductive materials satisfying this demand include squaric acid, methine dyes, cyanine dyes, pyrylium dyes, thiapyrylium dyes, polyazo dyes, and phthalocyanine dyes. Of these, squalic acid, methine dyes, cyanine dyes, pyrylium dyes, thiapyrylium dyes are relatively easy to make the spectral sensitivity longer wavelength, but lack the practical stability of repeated use. However, polyazo dyes have difficulty in making absorption to a longer wavelength, and have manufacturing difficulties. On the other hand, many phthalocyanine dyes have an absorption peak in the wavelength range of 600 nm or more and further have an absorption wavelength extending to a relatively long wavelength range compared to other dyes, and thus are expected as a charge generating agent for a long wavelength light source. Has been widely considered.

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 to be selected for photographic photoreceptors. For example, it is reported that there are various crystal types in TiOPc, and there are large differences in chargeability, dark decay, sensitivity, etc. due to the difference in the crystal types. In Japanese Patent Laid-Open No. 59-49544, the Bragg angle (2θ ±
0.2 °) = 9.2 °, 13.1 °, 20.7 °, 2
It is described that those which give strong X-ray diffraction peaks at 6.2 ° and 27.1 ° are preferable. In addition, JP-A-59-1
In Japanese Patent No. 66959, a vapor-deposited film of TiOPc is left in saturated steam of tetrahydrofuran for 1 to 24 hours to change the crystal type to form a charge generation layer. The X-ray diffraction spectrum has a small number of peaks and a wide width, and Bragg angle (2θ ± 0.2 °) = 7.5 °, 12.6 °, 13.
It is shown that strong diffraction peaks are shown at 0 °, 25.4 °, 26.2 °, and 28.6 °.

As a result of various studies on the method for producing TiOPc, the present inventors have found that in the X-ray diffraction spectrum,
Bragg angle (2θ ± 0.2 °) 9.3 °, 10.6 °,
TiOPc (hereinafter referred to as "β-type Ti" having main diffraction peaks at 13.2 °, 15.2 °, 20.8 °, 26.3 °
OPc ") and 7.6 °, 10.2 °, 2
TiOPc having main diffraction peaks at 2.3 °, 25.3 °, and 28.6 ° (hereinafter abbreviated as “α-type TiOPc”), and further 7.0 °, 15.6 °, 23.4.
TiOPc having major diffraction peaks at 2 ° and 25.6 °
The existence of the crystal form was confirmed, and a method for producing them was devised (JP-A-62-256865, JP-A-62-25).
6867, JP-A-63-366).

In the above-mentioned production method, it is necessary to delicately control the temperature rising rate at the time of reacting orthophthalodinitrile with titanium tetrachloride, the filtration temperature after the reaction, etc. There was a tendency that crystal types coexist. Also,
According to JP-A-61-217050, dichlorotitanium phthalocyanine (hereinafter abbreviated as "TiCl ₂ Pc") is heated with concentrated ammonia water and then washed with acetone to obtain TiOPc, but the operation is complicated. However, the crystal form is liable to become a mixture of α type and β type.

[0006]

In the above-mentioned conventional method, T formed by the condensation reaction of orthophthalodinitrile with titanium tetrachloride or titanium trichloride is represented by the following formulas (1) and (2).
Although TiOPc is obtained by hydrolyzing iCl ₂ Pc with water, ammonia water, etc., not only the above-mentioned drawbacks but also the operation is complicated and the TiCl ₂ Pc in the following formula

[0007]

[Chemical 1]

Since the hydrolysis requires a long time, the obtained TiOPc has a low crystallinity and is amorphous, and it is a mixture of various crystal forms, the crystal form required for use in an electrophotographic photoreceptor is determined. 2-ethoxyethanol, diglyme, dioxane, tetrahydrofuran,
It involves problems such as the need for crystallization and crystal conversion by treatment with an organic solvent such as N, N-dimethylformamide, N-methylpyrrolidone, pyridine and morpholine.

As a method other than hydrolysis, Japanese Patent Application Laid-Open No. 3-50270 discloses TiCl ₂ Pc or dibromotitanium phthalocyanine (hereinafter referred to as “TiBr ₂ P”).
abbreviated as “c”) with a specific organic solvent, TiOPc having a specific crystal type can be selectively produced. However, when this TiOPc is applied to an electrophotographic photosensitive member, sensitivity and charging property are improved. However, it was not sufficient in terms of dark decay, durability, that is, stability of potential due to repeated use.

The main object of the present invention is to provide a method for producing β-type TiOPc which solves the above-mentioned problems in production. Another object of the present invention is 80
An object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity in a long wavelength region around 0 nm and having more excellent potential stability by repeated use.

[0011]

The inventors of the present invention have made intensive studies to solve the above-mentioned problems in production and provide an electrophotographic photoreceptor having excellent characteristics. As a result, TiCl ₂ P
The present invention has found a method for obtaining β-type TiOPc from dihalogeno titanium phthalocyanine (hereinafter abbreviated as “TiX ₂ Pc”) such as c, TiBr ₂ Pc, etc., by a method other than conventionally known hydrolysis, and the present invention Reached

That is, the gist of the present invention resides in a method for producing β-type TiOPc, which comprises contacting TiX ₂ Pc with a mixed solvent containing N-alkyllactams and water in the presence of a deoxidizing agent. With this structure, β-type TiOPc can be manufactured very easily. In addition, other crystal type TiOPc recognized in the conventional method is not mixed,
Since the crystallinity is sufficiently high, it can be put to practical use as it is, but if necessary, water, methanol, acetone, N
-Methylpyrrolidone, Dimedyl sulfoxide, N, N-
It is also possible to purify with a solvent such as dimethylformamide. Further, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, β obtained by the above-mentioned method for the photosensitive layer is used.
The inclusion of the type TiOPc also achieves the object of providing an electrophotographic photoreceptor having high sensitivity in a long wavelength region around 800 nm and excellent durability.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The β-type TiOPc which is the object of the present invention is Cu-Kα.
In the X-ray diffraction spectrum using X-ray, the Bragg angle (2θ ± 0.2 °) 9.3 °, 10.6 °, 13.2
Usually, the main diffraction peaks are shown at °, 15.2 °, 20.8 °, and 26.3 °, but other crystallographically similar crystal forms are also included. The structural formula of the β-type TiOPc is represented by the following general formula [1].

[0014]

[Chemical 2]

(In the formula, X represents a halogen atom, and n is 0.
Represents a number from 1 to 1. )

The method for producing β-type TiOPc according to the present invention will be described with reference to specific examples. Although the method for synthesizing TiX ₂ Pc as a raw material is not limited, it can be usually 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 from the viewpoint of cost. Examples of the inert solvent include trichlorobenzene, α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenyl ether, diphenylmethane, diphenylethane, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, and triethylene glycol dialkyl ether. High boiling organic solvents that are inert to the reaction are preferred.

The reaction temperature is usually 150 to 300 ° C., especially 1
80-250 degreeC is preferable. After reaction, TiX _{2 formed}
Pc is usually filtered off and washed with the solvent used for the reaction to remove impurities formed during the reaction and unreacted components. Next, the solvent used in the reaction is usually removed by washing with an inert solvent such as alcohols such as methanol, ethanol and isopropyl alcohol, ethers such as tetrahydrofuran and diethyl ether.

The TiX ₂ Pc thus obtained was treated in the presence of a deoxidizing agent,
Β-type TiOPc can be obtained by contacting with a mixed solvent containing N-alkyl lactams and water. As the deoxidizer, any compound can be used as long as it is a basic compound, and for example, γ-picoline, triethylamine, NaOH, KOH, Na ₂ CO ₃ , CH ₃ COON.
a, ammonia and the like. The amount of these deoxidizers is usually 0.1 to 1 with respect to 1 mol of TiX ₂ Pc.
5 mol, especially 1 to 8 mol is preferred.

Examples of N-alkyllactams include N-methylpyrrolidone and 1,3-dimethyl-2-imidazolidine. In addition, the mixing ratio (volume ratio) of these N-alkyl lactams and water is preferably 1 to 50%, more preferably 1 to 30% with respect to N-alkyl lactams.
% Range is preferred. The mixed solvent preferably consists essentially of N-alkyl lactams and water,
Other solvents may be mixed as long as the N-alkyl lactams are mainly composed of water.

The temperature at which TiX ₂ Pc and the mixed solvent are brought into contact with each other can be arbitrarily selected, but is preferably 50 to 200 ° C., particularly preferably 90 to 150 ° C. Also, TiX ₂ P
The contact time between c and the mixed solvent depends on the type and addition amount of the deoxidizer,
Although it depends on the type of organic solvent, the mixing ratio of water and the contact temperature, it is usually effective for 1 to 3 hours at 90 to 150 ° C.

The use ratio of TiX ₂ Pc and the mixed solvent is not particularly limited, 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 used is too low, the contact efficiency becomes poor and the production rate of TiOPc decreases. The method of contacting TiX ₂ Pc and the mixed solvent in the presence of a deoxidizing agent is not particularly limited, but a method of contacting and mixing both in a stirring tank is preferable. A method of flowing a mixed solvent containing a deoxidizing agent through a column packed with TiX ₂ Pc can also be adopted, but any method may be used as long as they are brought into contact with each other in the presence of the deoxidizing agent.

Β-type TiOPc thus obtained
Other than the crystal type TiOPc recognized in the conventional method is not mixed and the crystallinity is sufficiently high that it can be put to practical use as it is, but if necessary, water, methanol, acetone, N-methylpyrrolidone is used. , Dimethyl sulfoxide,
It is also possible to purify with a solvent such as N, N-dimethylformamide.

The TiOPc crystal is excellent in, for example, a function as a photoconductor, and is used as an electrophotographic photoreceptor, a solar cell,
It can be applied to electronic materials such as sensors and switching elements. Hereinafter, an example in which the TiOPc crystal of the present invention is applied as a charge generating agent in a photosensitive layer in an electrophotographic photosensitive member having a photosensitive layer on a conductive support 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 liquid for coating the photosensitive layer in a state of being mixed with the binder resin. Various solvents may be used as the dispersion medium. For example, diethyl ether, dimethoxymethane, tetrahydrofuran, 1,2-
Ethers such as dimethoxyethane; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; alcohols such as methanol, ethanol and propanol can be used alone or in admixture of two or more.

As the binder resin, polyvinyl butyral,
Polyvinyl acetal, polyester, polycarbonate, polystyrene, polyester carbonate, polysulfone, polyimide, polymethyl methacrylate, vinyl chloride and other vinyl polymers, and their copolymers, phenoxy, epoxy, silicone resins, etc. or partially cross-linked cured products thereof. Etc. can be used alone or in combination of two or more.

As a method of dispersing the TiOPc crystal, a known method such as a ball mill, a sand grind mill, a planetary mill or a roll mill can be used. Examples of the method for mixing the binder resin and the TiOPc particles include, for example, a method of dispersing the binder resin as powder or a polymer solution thereof at the same time during the dispersion treatment of the TiOPc particles, and a method of dispersing the dispersion liquid in the polymer solution of the binder resin. Any method such as a method of mixing or a method of mixing a polymer solution in a dispersion liquid may be used.

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

If necessary, a charge transfer agent or another charge generating agent may be included. Examples of the charge transfer agent include electron-withdrawing substances such as 2,4,7-trinitrofluorenone and tetracyanoxydimethane, heterocyclic compounds such as carbazole, indole, imidazole, oxazole, oxadiazole, pyrazoline and thiazole, Examples thereof include aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, and electron-donating substances such as polymers having a group composed of these compounds in the main chain or side chain. The charge generating agent may be any one 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 thereof include methine dyes, cyanine dyes, pyrylium dyes, thiapyrylium dyes, polyazo dyes, and phthalocyanine dyes other than the present invention. Regarding the ratio of the charge transfer agent or charge generating agent to the binder resin, the charge transfer agent or charge generating agent is used in the range of 5 to 500 parts by weight based on 100 parts by weight of the binder resin.

Using the dispersion liquid thus prepared,
(1) A charge generation layer is formed on a conductive support, and a charge transfer layer is laminated on the charge generation layer to form a photosensitive layer, or
(2) A charge transfer layer is formed on a conductive support, and a charge generating layer is formed on the charge transfer layer to form a photosensitive layer, or (3) the dispersion is formed on a conductive support. Can be used to form a charge generation layer to form a photosensitive layer, thereby forming the photosensitive layer. The film thickness of the charge generation layer is 0.1 when laminated with the charge transfer layer to form a photosensitive layer.
The range of μm to 10 μm is preferable, and the film thickness of the charge transfer layer is preferably 5 μm to 60 μm. The thickness of the charge generation layer is 5 when the photosensitive layer is formed with a single structure of only the charge generation layer.
The range of μm to 60 μm is preferable.

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

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

A known barrier layer, which is commonly used, may be provided between the conductive support and the photosensitive layer.
Examples of the barrier layer include an inorganic layer such as aluminum anodic oxide coating, aluminum oxide and aluminum hydroxide, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, and other organic layers. Layers are used. The thickness of the barrier layer is preferably in the range of 0.1 μm to 20 μm, and 0.1 μm to 10 μm
It is most effective to be used in the range of.

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

[0035]

EXAMPLES 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 examples unless it exceeds the gist. Ti
Production Example of Cl ₂ Pc In a 1 L reaction flask equipped with a thermometer, a stirrer, and a reflux condenser, orthophthalodinitrile 92.
0 g and α-chloronaphthalene (600 ml) were charged, and 20 ml of titanium tetrachloride was added dropwise with stirring. After dropping, the temperature is raised to 2
After reacting at 00 to 220 ° C for 5 hours, it is allowed to cool to 130 ° C.
The mixture was hot filtered at 400 ° C., heated at 120 ° C. to 400 ml of α-chloronaphthalene, and then washed and dried with 200 ml of methanol to obtain 61.3 g of a blue powder of TiCl ₂ Pc. The elemental analysis values of the obtained TiCl ₂ Pc are as shown in Table 1 below.

[0036]

[Table 1]

Example 1 10.0 g of TiCl ₂ Pc (0.01584) was placed in a 200 ml reaction flask equipped with a thermometer, a stirrer and a reflux condenser.
mol) and 2.95 g of γ-picoline as a deoxidizer.
(0.03168 mol), N-methylpyrrolidone 98
100 ml of a mixed solvent (N-methylpyrrolidone 98 ml, water 2 ml) in which water 2 was mixed was charged to 135 ° C.
After heating to (reflux state) and stirring for 3 hours, the mixture was cooled to 100 ° C. and filtered, and the obtained cake was washed with methanol and dried to obtain 5.8 g of β-type TiOPc blue powder. The X-ray diffraction spectrum of the β-type TiOPc thus obtained is shown in FIG.

Example 2 NaOH 1.27 was used instead of γ-picoline as a deoxidizing agent.
g (0.03168 mol), the mixing ratio of N-methylpyrrolidone and water was changed to water 2 for N-methylpyrrolidone 98, and water 10 for N-methylpyrrolidone 90.
An experiment was conducted in the same manner as in Example 1 except that The X-ray diffraction spectrum of the β-type TiOPc thus obtained is shown in FIG.
Shown in.

Example 3 Instead of γ-picoline as a deoxidizing agent, Na ₂ CO ₃ 1.
68 g (0.01584 mol), Example 1 except that the mixing ratio of N-methylpyrrolidone and water was changed to water 2 for N-methylpyrrolidone 98 and water 10 for N-methylpyrrolidone 90. The same experiment was conducted. The X-ray diffraction spectrum of the β-type TiOPc thus obtained is shown in FIG.

Example 4 In place of γ-picoline as a deoxidizing agent, 5.79 g of 28% aqueous ammonia (ammonia: 0.09504 mol),
An experiment was conducted in the same manner as in Example 1 except that the mixing ratio of N-methylpyrrolidone and water was changed to N-methylpyrrolidone 98 of water 2 and N-methylpyrrolidone 90 of water 10. X of β-type TiOPc thus obtained
The line diffraction spectrum is shown in FIG.

Comparative Example 1 An experiment was conducted in the same manner as in Production Example 1 except that γ-picoline was not added as a deoxidizing agent. Β-type TiOP thus obtained
The X-ray diffraction spectrum of c is shown in FIG. Comparative Example 2 Without adding γ-picoline as a deoxidizing agent, the mixing ratio of N-methylpyrrolidone and water was changed to water 2 for N-methylpyrrolidone 98 and water 10 for N-methylpyrrolidone 90. An experiment was performed in the same manner as in Production Example 1 except that the above was performed. The X-ray diffraction spectrum of the β-type TiOPc thus obtained is shown in FIG.

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

[0043]

[Chemical 3]

14 parts by weight of the hydrazone compound shown below,

[0045]

[Chemical 4]

And 1.5 parts by weight of the following cyano compound

[0047]

[Chemical 5]

And a polycarbonate resin (trade name: Novalex (trademark) 7030A manufactured by Mitsubishi Chemical Corporation) 1
A liquid prepared by dissolving 100 parts by weight of 1000 parts by weight of 1,4-dioxane was applied by a film applicator, and a charge transfer layer was provided so that the film thickness after drying was 17 μm. The photoconductor thus obtained is referred to as photoconductor A.

Example 6 Example 5 was repeated, except that the β-type TiOPc produced in Example 2 was used in place of the β-type TiOPc used in Example 5.
A photoconductor was prepared in the same manner as in. The photoconductor thus obtained is referred to as photoconductor B. Example 7 Example 5 was repeated except that the β-type TiOPc used in Example 5 was replaced by the β-type TiOPc produced in Example 3.
A photoconductor was prepared in the same manner as in. The photoconductor thus obtained is referred to as a photoconductor C.

Example 8 Example 5 was repeated except that the β-type TiOPc produced in Example 4 was used in place of the β-type TiOPc used in Example 5.
A photoconductor was prepared in the same manner as in. The photoconductor thus obtained is referred to as a photoconductor D.

Comparative Example 3 Example 5 was repeated except that the β-type TiOPc produced in Comparative Example 1 was used instead of the β-type TiOPc used in Example 5.
A photoconductor was prepared in the same manner as in. The photoconductor thus obtained is referred to as a comparative photoconductor E. Comparative Example 4 Example 5 was repeated except that the β-type TiOPc used in Example 5 was replaced by the β-type TiOPc produced in Comparative Example 2.
A photoconductor was prepared in the same manner as in. The photoconductor thus obtained is referred to as a comparative photoconductor F.

Evaluation: The obtained photoreceptor was measured for initial electric characteristics in terms of charging potential, dark decay, residual potential, and half-exposure sensitivity using an electrostatic copying paper tester (Kawaguchi Denki Seisakusho, Model EPA-8100). did. That is, the photoreceptor is negatively charged by corona discharge by an applied voltage set so that the corona current becomes 35 μA in a dark place, and after 2 seconds, monochromatic light of 780 nm (1.0 μm) is emitted.
(W / cm ² ) is continuously exposed for 10 seconds, the decay of the surface potential is measured, and the exposure amount (sensitivity required to reduce the charging potential, dark decay, residual potential, and surface potential from -700V to -350V). ) Was asked. The results are shown in Table 2.

[0053]

[Table 2]

From Table 2, the photoconductors A, B, C and D
It can be seen that has a higher sensitivity to monochromatic light of 780 nm than the comparative photoconductors E and F. Next, the photoconductor D
For the comparative photoconductor F, the electrostatic exposure repetition potential stability was evaluated using an electrostatic copying paper test device (Kawaguchi Denki Seisakusho, Model EPA-8100). That is, in a dark place, the photoreceptor is negatively charged by corona discharge by an applied voltage set so that the corona current becomes 35 μA, and after 0.5 seconds, white light (400 lux) is continuously exposed for 3 seconds. Repeated 2000 times, using the initial charging potential as a reference, how much charge (V
o Retention rate: ratio of potential after repetition to initial potential) and change in residual potential (ΔVr: residual potential after repetition−initial residual potential) were determined. The results are shown in Table 3.

[0055]

[Table 3]

From Table 3, it can be seen that the photoconductor D is superior to the comparative photoconductor F in potential stability upon repeated use.

[0057]

The present invention provides a method for producing β-type TiOPc extremely easily as compared with the conventional method,
Manufacturing on an industrial scale is also very advantageous. Further, by applying β-type TiOPc obtained by the production method according to the present invention to an electrophotographic photosensitive member, an electron having high sensitivity in a long wavelength region around 800 nm and more excellent potential stability during repeated use is obtained. A photographic photoreceptor can be provided.

[Brief description of drawings]

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

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

FIG. 3 is an X-ray diffraction spectrum diagram of β-type TiOPc obtained in Example 3.

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

5 is an X-ray diffraction spectrum diagram of β-type TiOPc obtained in Comparative Example 1. FIG.

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

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-50270 (JP, A) JP-A-5-86302 (JP, A) JP-A-8-27392 (JP, A) JP-A-4- 246472 (JP, A) JP 62-256865 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09B 67/50 C09B 67/10-67/12 C09B 67/20 G03G 5/06 371 C09B 47/00 C07D 487/22

Claims (4)

(57) [Claims] 1. A method for producing β-type oxytitanium phthalocyanine, which comprises contacting dihalogeno titanium phthalocyanine with a mixed solvent containing N-alkyl lactams and water in the presence of a deoxidizing agent. 2. The production method according to claim 1, wherein the mixing ratio of water to the N-alkyllactams is 1 to 50%. 3. The production method according to claim 1, wherein the amount of the deoxidizing agent present is 0.1 to 15 mol with respect to 1 mol of dihalogeno titanium phthalocyanine. 4. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains an oxytitanium phthalocyanine obtained by the method according to claim 1.