KR100347324B1 - Mixed Phthalocyanine Crystal and Electrophotographic Photoreceptor Using Thereof - Google Patents

Abstract

The present invention is characterized by having a main diffraction peak at 7.5 °, 9.1 °, 16.7 °, 17.4 °, 21.4 °, and 27.3 ° at Bragg angle (2θ ± 0.2 °) by X-ray diffraction analysis in Cu K alpha light source. The present invention relates to a mixed crystal of metal-free phthalocyanine and oxo titanyl phthalocyanine and an electrophotographic photosensitive member using the mixed crystal as a charge generating material. The present invention has excellent sensitivity, chargeability, and dark attenuation characteristics, and is excellent in repeated use. An electrophotographic photosensitive member that exhibits light stability can be provided.

Description

Phthalocyanine mixed crystal and electrophotographic photosensitive member using the same {Mixed Phthalocyanine Crystal and Electrophotographic Photoreceptor Using Thereof}

The present invention relates to a mixed crystal of metal free phthalocyanine and oxotitanyl phthalocyanine and an electrophotographic photosensitive member prepared using the same.

In the conventional electrophotographic photoreceptor, inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide, which are formed by vacuum deposition on a substrate such as aluminum, which is a conductive material, are used. While these inorganic photoconductors have excellent durability and sensitivity characteristics, they are rarely used as electrophotographic photoconductors due to the disadvantages of complicated manufacturing process, high manufacturing cost, and deterioration of environmental stability.

On the other hand, as an organic photoreceptor to improve the disadvantages of the inorganic photoreceptor as a charge generating material Chlorocyan Blue or squalene (Squaraine) is formed on the aluminum substrate to a thickness of about 1㎛, polyvinylcarbazole ( Polyvinylcarbazole) or pyrazoline derivative compounds are used as charge transport materials. However, such a photoreceptor has a disadvantage in that it has no sensitivity at a wavelength of 700 nm or more.

Recently, a photoreceptor in which a metal-free phthalocyanine pigment, which absorbs light in the wavelength region of a laser diode, around 800 nm has been applied as a charge generating material. Absorption spectra and photoconductivity of metal-free phthalocyanines vary greatly depending on the crystalline form, and metal-free phthalocyanines of various crystal forms such as thermodynamically unstable α-type, γ-type, and stable β-type are known. Since the crystalline forms of the α, β and γ forms do not have sufficient sensitivity in the near-infrared region, which is the wavelength of a laser beam, the development of new crystalline forms has been advanced.

U.S. Patent No. 3,357,989 describes a TYPE-type metal-free phthalocyanine, JP-A-58-182639 describes τ-type metal-free phthalocyanine, and JP-A-60-243089 describes τ'-type metal-free phthalocyanine. X-type metal-free phthalocyanine has a problem in that it is applied as a charge generating material because the industrial manufacturing method is difficult and the sensitivity is slow. In addition, the τ, τ 'type metal-free phthalocyanine improves sensitivity, but has a disadvantage in that the change over time is not good in repeated use because of lack of chargeability and in particular, a bad attenuation characteristic.

Absorption spectrum and photoconductivity of the phthalocyanine compound have different properties depending on the center metal, in addition to the crystal form change. Oxotitanyl phthalocyanine, which is a titanium as the center metal, is used as an electrophotographic photosensitive member for various crystal forms. For example, the α crystal form is Japanese Patent Laid-Open No. 61-217050, US Patent No. 4,728,592, and the β crystal form is Japanese Patent Laid-Open No. 59-49544, US Patent No. 4,664,997, and C crystal form is Japanese Patent Laid-Open No. 62-256865, D crystal form. Are disclosed in Japanese Patent Application Laid-Open No. 62-67094, US Patent No. 5,183,886, Y Crystal Form in Japanese Patent Publication No. 64-17066, γ Crystal Form in Japanese Patent Publication No. 1-299874, and ω Crystal Form in Japanese Patent Publication No. 2-99969 have. However, oxo titanyl phthalocyanine has excellent sensitivity characteristics in the long wavelength range, but it is difficult to stably prepare a crystalline form having excellent sensitivity characteristics and to store it stably for a long time.

On the other hand, an example of applying a mixture of metal-free phthalocyanine and metal phthalocyanine instead of using each of them is shown in Japanese Patent Application Laid-Open No. 1-163749. However, since two or more types of phthalocyanines are simply mixed and used, the effect of improving the electrophotographic properties is insufficient. On the other hand, patents relating to the mixed crystals of metal-based phthalocyanines including metal-free phthalocyanine are disclosed in Japanese Patent Laid-Open Nos. 2-84661 and 2-170166 and the like, and mixed crystals are produced by a vacuum deposition apparatus. In the X-ray diffraction analysis, the mixed peak having the maximum peak at Bragg angles (2θ ± 0.2 degrees) of 6.6 ° and 14.0 ° has a problem of low sensitivity and low stability for repeated use.

An object of the present invention is to provide an electrophotographic photosensitive member which is excellent in sensitivity, chargeability and dark attenuation characteristics and excellent in light stability and environmental stability in repeated use by solving the problems of the prior art as described above.

In other words, one aspect of the present invention is the main diffraction peak at 7.5 °, 9.1 °, 16.7 °, 17.4 °, 21.4 ° and 27.3 ° with Bragg angle (2θ ± 0.2 °) by X-ray diffraction analysis in Cu K alpha light source. It is to provide a mixed crystal of the metal-free phthalocyanine and oxo titanyl phthalocyanine characterized by having.

Another aspect of the present invention consists of a charge generation layer composed of a conductive substrate / a charge generation material and a binder resin / a charge transfer layer composed of a charge transfer material and a binder resin or a conductive substrate / charge generation material, a charge transfer material and An electrophotographic photosensitive member comprising a photosensitive layer composed of a binder resin, the electrophotographic photosensitive member characterized by using a mixed crystal of metal free phthalocyanine and oxo titanyl phthalocyanine as a charge generating material.

1 is a partial cross-sectional structure diagram of a stacked electrophotographic photosensitive member;

2 is a partial cross-sectional structure diagram of a tomographic electrophotographic photosensitive member;

3 is an X-ray diffraction spectrum of β-type metal-free phthalocyanine,

4 is an X-ray diffraction spectrum of τ-free metal phthalocyanine,

5 is an X-ray diffraction spectrum of α-type oxo titanyl phthalocyanine,

6 is an X-ray diffraction spectrum of β-type oxo titanyl phthalocyanine,

7 is an X-ray diffraction spectrum of a mixed crystal according to Example 1, and

8 shows the X-ray diffraction spectrum of the mixed crystal crystal of Example 3.

Hereinafter, the present invention will be described in detail.

The mixed crystal of the metal-free phthalocyanine and oxo titanyl phthalocyanine according to the present invention is Bragg angle (2θ of 7.5 °, 9.1 °, 16.7 °, 17.4 °, 21.4 °, 27.3 ° by X-ray diffraction analysis in Cu-K alpha light source) ± 0.2 °), with a major diffraction peak. When this is applied as a charge generating material of the electrophotographic photosensitive member it can provide a good photosensitive member having excellent sensitivity and dark attenuation characteristics and stability even when repeated use.

Said mixed crystal crystal is manufactured by the following method.

In order to prepare a mixed crystal of the metal-free phthalocyanine and the oxo titanyl phthalocyanine of the present invention, the phthalocyanine mixture of a certain composition is converted to an amorphous form by using an acid paste method, and then gradually added to distilled water kept at low temperature to determine the mixed crystal. Water is precipitated, and dried mixed crystals are treated in a paintsaker and then purified with a solvent.

The composition ratio for preparing a mixed crystal of the metal-free phthalocyanine and the oxo titanyl phthalocyanine of the present invention is preferably 70 to 99.5 weight% of metal-free phthalocyanine, 0.5 to 30 weight% of oxo titanyl phthalocyanine, and more preferably metal-free. 80 to 99.5 weight percent of phthalocyanine, 0.5 to 20 weight percent of oxo titanyl phthalocyanine, most preferably 90 to 99 weight percent of metal-free phthalocyanine, and 1 to 10 weight percent of oxo titanyl phthalocyanine.

More detailed description is as follows. Metal-free phthalocyanine and oxo titanyl phthalocyanine are mixed in an appropriate ratio, dissolved in an inorganic acid such as concentrated sulfuric acid, and then precipitated while gradually falling into distilled water or a mixed solution of distilled water and methanol at 0 to 5 ° C. Next, the precipitate is washed several times with distilled water while maintaining the pH 6-7 of the washing water. If the pH of the washing water is maintained below 6 or more than 7, the phenomenon that the electrostatic properties such as sensitivity, chargeability and residual potential is lowered. The precipitate is dried and crystallized in a paint shaker at room temperature. After washing with distilled water or methanol, washed with a weak acid and weak alkaline aqueous solution, and finally washed with distilled water and dried. The bead for sand mill may be glass beads, stainless steel beads, zirconia beads, and the like. As a dispersion solvent, cellulose solvents such as glycerin, ethylene glycol, polyethylene glycol, ethylene glycol monomethyl ether, ketone solvents, and ester ketones may be used. System solvents are used, and in some cases, milling is also possible under conditions other than a dispersion solvent. Meanwhile, if necessary, salt, sodium carbonate, boric acid, or the like may be used as a dispersing aid.

The electrophotographic photosensitive member provided by the present invention has a structure as shown in FIGS. 1 and 2. FIG. 1A shows a stacked structure in which a charge generating layer 2 and a charge transport layer 3 are formed on a conductive support 1, and FIG. 2A shows a structure in which a photosensitive layer 6 is formed on a conductive support 1. 1B or 2B, an undercoat 4 may be added between the conductive support 1 and the charge generating layer 2 or the photosensitive layer 6, and the photoconductor may be added as shown in FIG. 1C or 2C. A protective layer 5 for protection may be formed on the top layer.

As the conductive support 1, aluminum, alumite, aluminum alloy, copper, stainless, nickel which are conductive materials; Aluminum, alumite, aluminum alloy, dium oxide, etc. formed on the plastic surface; Deposition of a conductive polymer or conductive particles on plastic or paper is used.

The charge generating layer 2 consists of the mixed crystal and the binder resin of the present invention. As the binder resin, polyvinyl butyral, polyarylate, polycarbonate, polyester, polyvinylacetate, polyamide, epoxy resin, urethane resin, casein, polyvinyl alcohol and the like can be used. In this case, the binder resin is used in an amount of 200 wt% or less relative to the phthalocyanine mixed crystal, and preferably in the range of 10 to 100 wt%. When the ratio of the binder resin is lower than this, the dispersion stability of the coating liquid for forming the charge generating layer is greatly decreased. On the contrary, when the ratio of the binder resin is higher than the binder resin, the sensitivity of the charge generating layer is insufficient, and thus, the photoresist cannot function as a photosensitive member. When using the binder resin, additives such as a plasticizer, an antioxidant, a flow increasing agent, and a pinhole removing agent may be used as necessary. It is preferable to use 0.1 to 5% by weight of the other additives relative to the weight of the phthalocyanine mixed crystal, and more preferably, add 0.1 to 2% by weight.

The charge generating layer 2 is formed on the conductive support 1 by using the coating solution formed by uniformly dispersing the mixed crystal of the present invention, the binder resin, and the additive as needed in an organic solvent. As the organic solvent used in the coating liquid for the charge generating layer, it is preferable to use one which does not affect the conductive support 1 or the undercoat 4 when the charge generating layer is formed. Suitable organic solvents include alcohols such as methanol, ethanol, isopropanol, n-butanol, 2-ethoxyethanol and 1-methoxy-2-propanol; Ketones such as acetone, methyl ethyl ketone and cyclohexanone; Amides such as N, N-dimethylacetamide and N, N-dimethylformamide; Ethers such as tetrahydrofuran and dioxane; Esters such as methyl acetate, ethyl acetate and butyl acetate; Hydrocarbons of benzene, toluene, xylene, cyclohexane and the like.

The method of forming the charge generating layer 2 using the coating liquid for the charge generating layer includes dip-coating, spray-coating, spin coating, and wire-bar coating. Coatting). It is preferable to carry out drying after coating as high as possible, and it is preferable to carry out within 5 minutes to 2 hours at 50-200 degreeC.

The charge generating layer 2 is preferably formed to a thickness of 0.05 to 5 탆, more preferably 0.05 to 2 탆. If the thickness of the charge generating layer is less than 0.05 µm, it is impossible to form a uniform layer and play a role as a charge generating layer. On the other hand, if the composition exceeds 5 μm, the electrostatic property, that is, the chargeability is lowered.

The charge transport layer 3 is composed of a charge transport material and a binder resin. Examples of charge transport materials include polymers such as poly-N-vinylcarbazole, polyvinylpyrene, polyvinyl benzothiophene, polyvinyl anthracene, oxadiazoles, triphenylamines, hydrazones, butadienes, stilbenes, and benzidines. The monomolecular compound of is applied. Structural formulas of representative transport materials are shown in Formulas 1-4.

The binder resin used for the charge transport layer 3 may be applied in the same manner as the resin used for the charge generating layer. The binder resin of the charge transport layer is preferably in the range of 30 to 500% relative to the weight of the charge transport material, and more preferably in the range of 50 to 300%. As a solvent for forming the coating solution, a kind that does not dissolve the charge generation layer 2 already formed may be used, and the coating method may also use the same method as used in the composition of the charge generation layer.

As for the thickness of the charge transport layer 3, 5-50 micrometers is suitable, More preferably, it is 10-40 micrometers. If the charge transport layer is less than 5 ㎛ composition, the initial chargeability is lowered, if more than 50 ㎛ composition has a disadvantage that the residual potential and sensitivity characteristics are sharply lowered.

In the photoconductor having a single layer structure as shown in FIG. 2, the photophthal layer 6 is formed by dispersing the phthalocyanine mixed crystal and the charge transport material in the binder resin in the present invention, and the mixing ratio of the charge transport material is higher than that of the bonding resin. The range of 30 to 200% by weight is effective, and the mixing ratio of the phthalocyanine mixed crystal is preferably 1 to 100% by weight relative to the charge transport material.

The undercoat 4 acts as a barrier for enhancing adhesion or charge transfer between the conductive support 1 and the charge generating layer 2 / photosensitive layer 6, and is casein, polyvinyl alcohol, polyvinyl butyral, polyamide And a material such as polyurethane. 0.1-10 micrometers is preferable and, as for thickness, 0.1-3 micrometers is more preferable. A conductive layer (not shown) may be formed between the conductive support 1 and the undercoat 4 to prevent interference caused by scattering in the image input by a defect or laser light on the surface of the support. The conductive layer is mainly composed of carbon black, metal powder, metal oxide and a suitable resin, and a thickness of 5 to 40 µm is appropriate, and more preferably 10 to 30 µm.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the scope of the present invention is not limited by the following examples.

Metal-free phthalocyanine and oxo titanyl phthalocyanine used in the following examples were prepared by the following method.

* Preparation of β-type metal-free phthalocyanine

14.5 g of aminoisoindoline was added to 50 g of trichlorobenzene, heated at 200 ° C. for 2 hours, and then the solvent was removed and washed sequentially with a 2% aqueous hydrochloric acid solution and a 2% aqueous sodium hydroxide solution. Next, while maintaining the pH of 6-7, it is sufficiently washed with distilled water and dried to obtain about 8 g of β-crystalline metal-free phthalocyanine. Figure 3 shows the X-ray diffraction spectrum of the β-type metal-free phthalocyanine prepared by the method as described above.

* Preparation of τ Type Metal-Free Phthalocyanine

10 g of the β-type metal-free phthalocyanine prepared above was added to 100 g of concentrated sulfuric acid maintained at 10 ° C., and then stirred sufficiently to dissolve. The sulfuric acid solution is gradually dropped into 2,000 ml of distilled water kept at 5 占 폚 or lower to precipitate crystals, followed by washing with distilled water sufficiently. At this time, 9.5 g of the obtained phthalocyanine is milled together with 100 g of a dispersion solvent polyethylene glycol (polyethyleneglycol) at a sand mill at 70 to 120 ° C. for 8 to 15 hours. After washing with a sufficient amount of distilled water and methanol, and dried under reduced pressure in a drying oven at about 70 ℃ to obtain 9.0g of τ-type metal-free phthalocyanine. Figure 4 shows the X-ray diffraction spectrum of the τ-type metal-free phthalocyanine produced by the above method.

* Preparation of α-type oxo titanyl phthalocyanine

The synthesis of α-type oxo titanyl phthalocyanine used in the present invention was by the method disclosed in US Pat. No. 4,728,592. 40 g of 1,2-dicyanide benzene and 18 g of titanium tetrachloride were added to 500 ml of α-naphthalene and reacted for about 3 hours at a temperature of about 240 to 250 ° C. and a nitrogen atmosphere. It was then slowly cooled and purified to give a solid product. 300 ml of concentrated ammonia water and 300 ml of pyridine were added to the recovered product titanyl phthalocyanine and stirred with reflux for about 1 hour. The oxo titanyl phthalocyanine obtained at this time was washed with N, N-dimethylformaldehyde, washed with acetone, and dried under reduced pressure at room temperature. Figure 5 shows the X-ray diffraction spectrum of the α-type oxo titanyl phthalocyanine prepared by the method as described above.

* Preparation of β-type oxo titanyl phthalocyanine

In a nitrogen atmosphere, 335 ml of α-Chloronaphthalene is added to a flask containing 48.75 g of 1,2-dicyanated benzene, and 11 ml of titanium tetrachloride is diluted with about 40 ml of α-naphthalene. Drop it. At this time, the reactor is heated to 200-220 ° C. at room temperature for about 30-40 minutes, and the diluted titanium tetrachloride solution is added within the same time and then mixed for about 4-5 hours. The reaction solution is then cooled to about 100-130 ° C. and purified. At this time, it is first washed with about 100 ml of α-naphthalene and then with about 400 ml of hot methanol. After that, add about 400 ml of distilled water, stir while heating for about 1 hour, and wash until the pH of the washing water is 6-7. Subsequently, 400 ml of N-methyl-2-pyrrolidone at about 140 ° C. was added to the product oxo titanyl phthalocyanine, which was stirred for about 30 minutes, followed by washing. Wash with methanol. Finally, it is dried under reduced pressure at room temperature to obtain 43 g of oxo titanyl phthalocyanine. Fig. 6 shows the X-ray diffraction spectrum of β-type oxo titanyl phthalocyanine.

Example 1

9.7 g of β-type metal-free phthalocyanine and 0.3 g of α-type oxo titanyl phthalocyanine are slowly added to 100 g of concentrated sulfuric acid and stirred sufficiently to dissolve. Phthalocyanine is precipitated by slowly adding sulfuric acid solution to 2,000 ml of distilled water maintained at 5 ° C. or lower, washed with distilled water and dried. 9.5 g of the phthalocyanine obtained at this time, 50 g of a dispersing aid, and 300 g of polyethylene glycol were added together to a paint shaker mill and crystallized at room temperature for 3 to 8 hours. Then, phthalocyanine is recovered by washing with distilled water or methanol, followed by primary washing with 2% aqueous sulfuric acid solution. Finally, it is sufficiently washed with distilled water until it reaches pH 6-7 and dried to obtain 9.1 g of a mixed crystal of metal-free phthalocyanine and oxo titanyl phthalocyanine. Figure 7 shows the X-ray diffraction spectrum of the mixed crystal of the metal-free phthalocyanine and oxo titanyl phthalocyanine prepared by the method as described above.

Example 2

Example 1 was carried out in the same manner as in Example 1, except that β-type oxo titanyl phthalocyanine was used instead of α-type oxo titanyl phthalocyanine.

Example 3

9.5 g of β-type metal-free phthalocyanine and 0.5 g of β-type oxo titanyl phthalocyanine are slowly added to 100 g of concentrated sulfuric acid and stirred sufficiently to dissolve. Phthalocyanine is precipitated by slowly adding sulfuric acid solution to 2,000 ml of distilled water maintained at 5 ° C. or lower, and the phthalocyanine is washed with distilled water and dried. At this time, 9.4 g of phthalocyanine and 300 g of a polyethylene glycol / glycerine mixed solvent were added together to a paint shaker mill and crystallized at room temperature for 3 to 10 hours. Then, phthalocyanine is recovered by washing with distilled water or methanol, followed by primary washing with 2% aqueous sulfuric acid solution. Finally, the mixture was washed sufficiently with distilled water until pH 6-7 and dried to obtain 9.0 g of a mixed crystal of metal-free phthalocyanine and oxo titanyl phthalocyanine. 8 shows the mixed crystal X-ray diffraction spectrum prepared by the above method.

Example 4

9.5 g of β-type metal-free phthalocyanine and 0.5 g of β-type oxo titanyl phthalocyanine are slowly added to 100 g of concentrated sulfuric acid and stirred to dissolve sufficiently. Phthalocyanine is precipitated by slowly adding sulfuric acid solution to 2,000 ml of distilled water maintained at 5 ° C. or lower, and the phthalocyanine is washed with distilled water and dried. At this time, 9.4 g of phthalocyanine and 300 g of polyethylene glycol were added together to a paint shaker mill and crystallized at room temperature for 3 to 15 hours. Then, phthalocyanine is recovered by washing with distilled water or methanol, followed by primary washing with 2% aqueous sulfuric acid solution. Finally, the mixture is sufficiently washed with distilled water until pH 6-7 and dried to obtain 9.1 g of a mixed crystal of metal-free phthalocyanine and oxo titanyl phthalocyanine.

Comparative Example 1

9.7 g of β-type metal-free phthalocyanine and 0.3 g of β-type oxo titanyl phthalocyanine were simply mixed to obtain a phthalocyanine mixed composition. The X-ray diffraction spectrum of this mixed composition is the same as in FIG.

Comparative Example 2

A phthalocyanine mixed composition was obtained by simply mixing 9.7 g of τ-type metal-free phthalocyanine and 0.3 g of β-type oxo titanyl phthalocyanine. The x-ray diffraction spectrum of this mixed composition is the same as in FIG.

The electrophotographic photosensitive member of the present invention, to which the phthalocyanine mixed crystals were applied, was carried out as follows in the embodiment of the method for producing a mixed crystal of the metal-free phthalocyanine and the oxo titanyl phthalocyanine.

Example 5

7.5 g of phthalocyanine mixed crystals according to Example 1 of the present invention, 5 g of polyvinyl butyral (Denka butyral # 6,000-C, Nippon Electric Chemical Co., Ltd.) and 487.5 g of tetrahydrofuran (THF) are mixed and 1 to 1,000 g of glass beads of 1.5 mm were added and milled for 10 hours by a ball mill to be dispersed. The coating solution for the charge generating layer was used for sedimentation coating on cylindrical alumite (diameter 30 mm) and dried at 70 ° C. for 20 minutes. At this time, the thickness of the charge generation layer was 0.3㎛.

40 g of the above-mentioned charge transport material of Formula 1, 40 g of charge transport material of Formula 3, and 100 g of polycarbonate resin (Panlite TS-2050, Nippon Chemical Industries, Ltd.) were added to 820 g of THF, followed by sufficient stirring to dissolve the charge transport layer. A coating solution was prepared. The charge transport layer was formed on the cylindrical alumite (diameter 30 mm) in which the charge generating layer was formed by the sedimentation coating method, and dried at 120 ° C. for 30 minutes. At this time, the thickness of the formed charge transport layer was 20㎛.

Dispersion stability of the coating solution for charge generation layer prepared above was left for 30 days in a thermostat repeating the temperature of 35 ℃ and -10 ℃ for 24 hours, and then visually observed whether the phthalocyanine crystals sink to the bottom of the mixture.

In addition, the physical properties of the prepared electrophotographic photosensitive member were measured by mounting the photosensitive drum prepared in the laser beam printer (Samsung Electronics Lazett ML-7050). When the photosensitive drum is used, the initial potential of the photosensitive member was initially charged at -800V when the charging roller was charged at -1.3kV under dark conditions, and the surface potential immediately after outputting 5,000 continuous images was -785V. The resistance to was excellent. In addition, sensitivity characteristics, dark attenuation characteristics and residual potentials were measured by Cynthia 91KSE (trade name Gentec), an electrostatic measuring device. Sensitivity (E ₁₀₀ ) was 1.02μJ / cm ² as the light energy required for the initial potential to fall to the potential level of -100V, dark attenuation was good at 95%, and residual potential was 1.0μJ / cm ² . When exposed to energy, the potential value of the drum surface, which appeared after 4 seconds, was -5V.

Examples 6-8

As shown in Table 1, instead of the phthalocyanine mixed crystals of Example 1, the crystals of Examples 2 to 4 were used in the same manner as in Example 5, and the results are shown in Table 1.

Comparative Examples 3 to 8

Instead of the phthalocyanine mixed crystal according to Example 1, as shown in Table 1, using the mixed composition of Comparative Examples 1 and 2, metal-free phthalocyanine, oxo titanyl phthalocyanine, respectively, was carried out in the same manner as in Example 5. Is shown in Table 1.

division Phthalocyanine Types Used Dispersion stability Initial potential potential (-V) 5kP continuous potential potential (-V) Sensitivity (μm / cm ² ) Darkness Attenuation (DD1,%) Residual potential (-V) E _1/2 E ₁₀₀ Example 5 Example 1 stability 800 785 0.46 1.02 95 5 Example 6 Example 2 stability 805 790 0.47 1.03 94 6 Example 7 Example 3 stability 795 785 0.45 1.00 95 5 Example 8 Example 4 stability 800 785 0.45 1.01 95 4 Comparative Example 3 β-type metal-free phthalocyanine stability 685 - 1.20 - 70 90 Comparative Example 4 τ type metal-free phthalocyanine stability 760 730 0.49 1.20 91 7 Comparative Example 5 α-type oxo titanyl phthalocyanine stability 805 735 0.43 0.98 94 5 Comparative Example 6 β-type oxo titanyl phthalocyanine Instability 800 750 0.51 1.38 96 10 Comparative Example 7 Comparative Example 1 Instability 700 - 1.05 - 75 60 Comparative Example 8 Comparative Example 2 Instability 770 745 0.49 1.22 92 7

As can be seen from the results of Table 1, Examples 5 to 8 have secured dispersion stability of the coating liquid compared to Comparative Examples 6 to 8. In addition, compared to Comparative Examples 3 and 4 using the metal-free phthalocyanine alone, the initial charging and darkening attenuation characteristics were better, and the aging over the repeated use was also excellent. In addition, compared to Comparative Examples 5 and 10 using oxo titanyl phthalocyanine alone, the stability against change with time was excellent.

Example 9

7.5 g of phthalocyanine mixed crystals according to Example 1 of the present invention, 5 g of polyvinyl butyral (BM-2, Nippon Co., Ltd.) and 487.5 g of 1-methoxy-2-propanol were mixed, 1,000 g of glass beads were added and dispersed by milling for 12 hours by a ball mill. Using the prepared coating solution for the charge generating layer was sedimentary coating on cylindrical alumite (diameter 30mm, length 25.1mm) and dried for 30 minutes at 120 ℃. At this time, the thickness of the charge generation layer was 0.3㎛.

80 g of the above-mentioned charge transport material of Formula 2 and 100 g of a polycarbonate resin (Toughzet, Japan Kwangkwang Heungsan Co., Ltd.) were added to 820 g of THF, followed by sufficient stirring to dissolve to prepare a coating solution for the charge transport layer. The charge transport layer was formed on cylindrical alumite having the charge generating layer formed by the sedimentation coating method, and dried at 120 ° C. for 30 minutes. At this time, the thickness of the formed charge transport layer was 20㎛.

The physical properties were measured in the same manner as in Example 5, and the results are shown in Table 2.

Example 10

Instead of the mixed crystal in Example 1 was used in the same manner as in Example 9 using the mixed crystal of Example 3, the results are shown in Table 2.

Comparative Example 9

Instead of the mixed crystals according to Example 1, τ-free metal phthalocyanine was used in the same manner as in Example 9, and the results are shown in Table 2.

Comparative Example 10

Instead of the mixed crystal of Example 1 was used in the same manner as in Example 9 using the mixed composition of Comparative Example 2, the results are shown in Table 2.

division Phthalocyanine Types Used Dispersion stability Initial potential potential (-V) 5kP continuous potential potential (-V) Sensitivity (μJ / cm ² ) Darkness Attenuation (DD1,%) Residual potential (-V) E _1/2 E ₁₀₀ Example 9 Example 1 stability 805 790 0.45 1.01 95 4 Example 10 Example 3 stability 805 795 0.44 0.99 96 5 Comparative Example 9 τ metal-free phthalocyanine stability 765 730 0.48 1.05 91 8 Comparative Example 10 Comparative Example 2 Instability 775 750 0.47 1.06 92 8

As can be seen in Table 2, Examples 9 and 10 are excellent in dispersion stability and initial chargeability, dark attenuation and stability over time compared to Comparative Examples 9 and 10.

An electrophotographic photosensitive member having excellent sensitivity, chargeability and dark attenuation characteristics, and excellent light stability and environmental safety against aging with repeated use by using a mixed crystal of metal-free phthalocyanine and oxo titanyl phthalocyanine according to the present invention. Can provide.

Claims (5)

Metal-free phthalocyanine characterized by having major diffraction peaks at 7.5 °, 9.1 °, 16.7 °, 17.4 °, 21.4 °, and 27.3 ° at Bragg angle (2θ ± 0.2 °) by X-ray diffraction analysis at Cu K alpha light source And a mixed crystal of oxo titanyl phthalocyanine. The mixed crystal of the metal-free phthalocyanine and oxo titanyl phthalocyanine according to claim 1, wherein the content of the metal-free phthalocyanine is 70 to 99.5% by weight and the content of the oxo titanyl phthalocyanine is 0.5 to 30% by weight. The method of claim 1, further comprising the steps of: 1) dissolving metal-free phthalocyanine and oxo titanyl phthalocyanine in an inorganic acid, 2) precipitating the solution by distilled water, 3) washing the precipitated material, 4) paintwash A crystallization crystal of metal free phthalocyanine and oxo titanyl phthalocyanine, which is prepared by crystallizing in a mill, and 5) washing the resultant. Charge generation layer composed of conductive substrate / charge generating material and binder resin / Photosensitive layer consisting of charge transfer layer composed of charge transfer material and binder resin An electrophotographic photosensitive member comprising: a mixed crystal of the metal-free phthalocyanine and oxo titanyl phthalocyanine according to claim 1 as the charge generating material. The method of claim 4, further comprising a protective layer for protecting the photoconductor, a lower layer formed on the conductive support to serve as a barrier for charge transfer, and / or a conductive layer for preventing interference during image input. Electrophotographic photosensitive member.