JPH08110649A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE: To obtain a photoreceptor stable to heat and light and having superior photosensitive characteristics even in a long wavelength region (near IR region) by blending an electric charge generating material with a specified phthalocyanine mixed crystal body. CONSTITUTION: When a photosensitive layer contg. an electric charge transferring material and an electric charge generating material is formed on an electrically conductive substrate to obtain an electrophotographic photoreceptor, a phthalocyanine mixed crystal body consisting of titanyl phthalocyanine and hydrogen phthalocyanine and having peaks at 6.8 deg., 7.4 deg., 15.0 deg., 24.7 deg., 26.2 deg. and 27.2 deg. Bragg angles (2θ±0.2 deg.) in its X-ray diffraction spectrum is incorporated into the electric charge generating material. In the spectrum, the ratio of peak intensity at 27.2 deg. to that at 6.8 deg. is >=1. That is, a phthalocyanine mixed crystal body consisting essentially of hydrogen phthalocyanine (metal-free phthalocyanine) and titanyl phthalocyanine is incorporated as an electron generating material into the photosensitive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member containing a phthalocyanine mixed crystal and having sensitivity in the visible region and near infrared region.

[0002]

2. Description of the Related Art Conventionally, electrophotographic photoreceptors having a photosensitive layer containing an inorganic photoconductor such as selenium, cadmium and zinc oxide as a main component have been widely used. The printability was not always satisfactory.

The organic photoconductor containing an organic photoconductive compound as a main component has many advantages such as variety of material design, excellent productivity, economical efficiency, no pollution and easy handling. Currently, active research and development are being conducted. In particular, a function-separated type photoconductor in which a different charge generation function and transport function are shared by different substances has become the main force of electrophotographic photoconductors.

On the other hand, in recent years, there has been a growing demand for using these organic photoconductors in the near infrared light region corresponding to semiconductor laser light (780 nm) as photoconductors for digital recording in laser printers, etc. The development of organic photoconductors having high-sensitivity characteristics is active.

[0005]

However, although the conventional electrophotographic photoreceptors have been partially put into practical use, they are not necessarily satisfactory in characteristics such as sensitivity, stability and life. is there. In addition, a new photoconductor having a high sensitivity in a long wavelength region which is a light emitting region of a semiconductor laser is desired to appear.

The present invention has been made from the above viewpoint, and provides a novel electrophotographic photosensitive member which is stable to heat and light and has sufficient sensitivity even in a long wavelength region (near infrared region). Is an issue.

[0007]

As a result of intensive studies to solve the above problems, the present inventor has found that the charge generation of an electrophotographic photosensitive member having a photosensitive layer containing a charge transport substance and a charge generating substance. By mixing a phthalocyanine mixed crystal obtained by mixing titanyl phthalocyanine and hydrogen phthalocyanine in a specific ratio to the substance, it is stable to heat and light, and has excellent photosensitivity even in the long wavelength region (near infrared region). The present invention has been completed by finding that an electrophotographic photoreceptor can be obtained.

That is, the present invention provides an electrophotographic photosensitive member comprising a conductive support and a photosensitive layer containing a charge transporting substance and a charge generating substance, wherein the charge generating substance comprises titanyl phthalocyanine and hydrogen phthalocyanine. , X
In the line diffraction spectrum, the Bragg angle (2θ ± 0.2
゜) 6.8 °, 7.4 °, 15.0 °, 24.7 °, 2
An electron containing a phthalocyanine mixed crystal having peaks at 6.2 ° and 27.2 ° and having a ratio of the peak intensity at 27.2 ° to the peak intensity at 6.8 ° of 1 or more. It is a photographic photoreceptor.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. <1> Phthalocyanine Mixed Crystal The photosensitive layer of the electrophotographic photosensitive member of the present invention contains a phthalocyanine mixed crystal composed mainly of hydrogen phthalocyanine (metal-free phthalocyanine) and titanyl phthalocyanine as electron generating substances.

The above-mentioned hydrogen phthalocyanine and titanyl phthalocyanine are synthesized by Moser and Thomas'"phthalocyaninecompound" (MOSER and THOMAS, "Phthalocianin").
e Compounds ") can be performed according to a known synthesis method, or any other synthesis method.

For example, in the case of titanyl phthalocyanine,
Heat melting of o-phthalonitrile and titanium tetrachloride, or
It can be obtained in good yield by a method of heating in the presence of an organic solvent such as α-chloronaphthalene or a method of heating 1,3-diiminoisoindoline and tetrabutoxytitanium with an organic solvent such as N-methylpyrrolidone. In the case of hydrogen phthalocyanine, it is synthesized by the above method without using a metal compound. In addition, the phthalocyanine-based compound thus synthesized may contain a chlorine-substituted phthalocyanine in which a hydrogen atom on the outer benzene ring is substituted with chlorine or the like.

The composition of the phthalocyanine mixed crystal used in the present invention is preferably such that the mole fractions of titanyl phthalocyanine and hydrogen phthalocyanine are 95 to 40% and 5 to 60%, respectively, and more preferably 95 to 50% and 5 to 50%. %, More preferably 95-60% and 5-40%, particularly preferably 9
It is 0 to 60% and 10 to 40%. If the mole fraction of titanyl phthalocyanine is too large, the stability of the mixed crystal may be lowered, and if it is too low, the sensitivity may be lowered and it may not be suitable for practical use.

As a method for producing a phthalocyanine mixed crystal,
For example, a method of dissolving titanyl phthalocyanine and hydrogen phthalocyanine in an acid and precipitating with a mixed solution of water and an organic solvent, or a method of precipitating the acid solution with alcohol, a method of dissolving titanyl phthalocyanine and hydrogen phthalocyanine in the same acid as above and precipitating in water Preferred is a method of treating the wet paste with an organic solvent, or a method of synthesizing hydrogen phthalocyanine (or titanyl phthalocyanine) in the presence of titanyl phthalocyanine (or hydrogen phthalocyanine) and treating it with an organic solvent in the presence of water. Can be mentioned.

Examples of the acid used in the above methods include inorganic acids such as sulfuric acid and phosphoric acid, and organic acids such as methanesulfonic acid, ethanesulfonic acid, fluoroacetic acid and chloroacetic acid. , Sulfuric acid, methanesulfonic acid and fluoroacetic acid are preferable, and further sulfuric acid,
Methanesulfonic acid is more preferred.

The amount of the acid used is not particularly limited as long as it dissolves the titanyl phthalocyanine and hydrogen phthalocyanine as the raw materials, but is preferably 10 to 1000 g with respect to 1 g of the total amount of the phthalocyanine compounds as the raw materials.
Is preferable, and 50 to 500 g is more preferable. The temperature of the reaction system during dissolution is preferably -20 to 80 ° C, more preferably -10 to 30 ° C. If the melting temperature exceeds 80 ° C, the raw material phthalocyanine compound may be decomposed, and if it is lower than -20 ° C, the solubility may deteriorate.

Examples of the alcohol used in the method (1) include aliphatic alcohols having 1 to 8 carbon atoms, alicyclic alcohols having 5 to 8 carbon atoms, and aromatic alcohols such as phenol. Of these, methanol, ethanol, propanol, butanol, pentanol, cyclopentanol, and cyclohexanol are preferable, and methanol, ethanol, propanol, butanol, and cyclohexanol are more preferable.

The amount of the mixed solution of water and an organic solvent, alcohol, or water used for precipitating the phthalocyanine mixed crystal from the acid solution of the phthalocyanine compound is 5 or 5 times the acid solution of the phthalocyanine compound.
The amount is preferably ˜100 times, more preferably 5 to 20 times. If the amount of the precipitation solvent with respect to the acid solution is less than 5 times, it is difficult to control heat generation, and
If the amount is more than 0 times, the operability may deteriorate as the amount increases. The deposition temperature in this case is preferably -20 to 80 ° C, more preferably -10 to 40 ° C.

As the organic solvent used in the methods 1 and 2, those having a relative dielectric constant of 20 or less are used. If an organic solvent having a relative dielectric constant of more than 20 is used, the polarity will be too high, and crystals that hinder the performance will grow, making it impossible to obtain the desired mixed crystal. Examples of the organic solvent having a relative dielectric constant of 20 or less include the following organic solvents. The relative dielectric constant at 20 ° C. of the compound is shown in parentheses after the name of each compound.

That is, aliphatic hydrocarbons having 4 to 12 carbon atoms, preferably 5 to 8 carbon atoms (1.7 to 2.0), alicyclic having 4 to 12 carbon atoms, preferably 5 to 8 carbon atoms Aromatic carbonization of formula hydrocarbons (2.0 to 2.5), benzene (2.3), toluene (2.4), xylene (2.3 to 2.7), ethylbenzene (2.6), etc. Hydrogen, chloropentane (6.6), butyl chloride (7.4), propyl chloride (7.7), tetrachloroethane (2.3), dichloroethane (10.7), carbon tetrachloride (2.2) , Chloroform (4.8), methylene chloride (7.8), butyl bromide (7.1), propyl bromide (8.1), ethyl bromide (9.4), methyl bromide (9.8). ) And other halogenated aliphatic hydrocarbons, chlorobenzene (5.7), dichlorobenzene (2.4 to 9.9). , Bromobenzene (5.
4), halogenated aromatic hydrocarbons such as dibromobenzene (2.6 to 7.4), methyl ethyl ketone (18.
5), pentanone (15.4), hexanone (16.
4), methylcyclohexanone (14.0), cyclohexanone (18.3), dipropyl ketone (12.6)
Such as ketones, dibutyl ether (3.1), dihexyl ether, ethylene glycol monomethyl ether (16.0), ethylene glycol dimethyl ether (5.5), tetrahydrofuran (7.4), dioxane (2.2), etc. Ethers, methyl acetate (6.7),
Ethyl acetate (6.0), propyl acetate (6.0), butyl acetate (5.0), methyl propionate (5.5), ethyl propionate (5.6), propyl propionate,
Esters such as butyl propionate (4.8), diethyl oxalate (1.8) and diethyl malonate (7.9), ethylamine (7.0), dipropylamine (3.
1), butylamine (4.9), dibutylamine (3.
0), pentylamine, ethylhexylamine, cyclohexylamine (4.7), dicyclohexylamine,
Aniline (7.1), toluidine (5.0-6.3),
Examples include amines such as piperidine (5.8), pyridine (12.3) and morpholine (7.4).

Among the above organic solvents, in the present invention,
Toluene, xylene, chlorobenzene, dichlorobenzene, chloroform, methylene chloride, dichloroethane, tetrahydrofuran, dipropyl ketone, ethylamine,
Ethyl acetate and the like are preferably used, and further, toluene,
Chlorobenzene, dichlorobenzene, dichloroethane,
Tetrahydrofuran, ethylamine and the like are more preferably used.

The mixing ratio of water in the mixed liquid of water and the above organic solvent used in the above method is preferably 5 to 90% by weight, and further 20 to 20% by weight based on the total amount of the mixed liquid.
It is more preferably 80% by weight.

The organic solvent treatment in the method (1) is carried out by using a general stirring device, and also by using a homomixer, a paint mixer, a ball mill, a sand mill, an attritor, a disperser, an ultrasonic disperser or the like. be able to. The treatment time is 1 minute to 120 hours, preferably 5 minutes to 50 hours, more preferably 10 minutes to 24 hours.
It may be a time range.

The phthalocyanine mixed crystal obtained by any one of the above methods (1) to (4) is isolated from the reaction solution by filtration and dried to be used as a raw material for the photosensitive layer of the electrophotographic photoreceptor of the present invention. Become. Alternatively, the phthalocyanine mixed crystal may be isolated from the reaction solution without solvent isolation and the like to obtain a coating solution for the photosensitive layer without a drying step.

The phthalocyanine mixed crystal used in the present invention has a Bragg angle (2θ ± 2) in an X-ray diffraction spectrum.
0.2 °) 6.8 °, 7.4 °, 15.0 °, 24.7
6. It has peaks at 2 °, 26.2 ° and 27.2 °, and 6.
The ratio of the peak intensity at 27.2 ° to the peak intensity at 8 ° is 1 or more, and the ratio is more preferably 1 or more and 30 or less, still more preferably 1 or more and 20 or less. In the X-ray diffraction spectrum, the dark decay time tends to be short in the phthalocyanine mixed crystal in which the ratio of the 27.2 ° peak intensity to the 6.8 ° peak intensity is too large, and in the phthalocyanine mixed crystal in which this ratio is less than 1, The sensitivity may be reduced and it may not be suitable for practical use.

The X-ray diffraction spectrum in the present invention is measured by the powder method, and the measurement conditions are as follows. Target: Cu Kα ray divergence slit: 1 ° Scattering slit: 1 ° Light receiving slit: 0.2 mm Step angle: 0.06 ° Counting time: 1 second <2> Electrophotographic photoconductor The electrophotographic photoconductor of the present invention is conductive. The photosensitive layer on the photosensitive support is characterized by containing at least one phthalocyanine mixed crystal composed of two types of phthalocyanine-based compounds having different central substances as charge generating substances together with a charge transporting substance. It may be in any known form.

That is, in the electrophotographic photoreceptor of the present invention, a photosensitive layer in which a charge generating layer containing a phthalocyanine mixed crystal as a charge generating substance as a main component and a charge transporting layer containing a charge transporting substance as a main component are laminated is made conductive. The structure may be provided on a support, or a photosensitive layer in which a charge generating substance is dispersed in a charge transporting substance may be provided on a conductive support. In addition, an intermediate layer made of an organic polymer such as polyamide resin, polyvinyl alcohol, or cellulose, or aluminum oxide may be provided between the conductive support and the photosensitive layer for the purpose of improving charging characteristics and adhesiveness. is there.

As described above, the electrophotographic photosensitive member of the present invention has a photosensitive layer formed on a conductive support, and the thickness of the photosensitive layer is preferably 5 to 50 μm. When a function-separated type of charge generation layer and charge transport layer is used as the photosensitive layer, the charge generation layer is preferably 0.001 to 10 μm
m, more preferably 0.2 to 5 μm. If the thickness of the charge generation layer is less than 0.001 μm, it is difficult to form the layer uniformly, and if it exceeds 10 μm, the electrophotographic properties tend to deteriorate. The thickness of the charge transport layer is preferably 5 to 50 μm, more preferably 8 to 20 μm.
Is. When the thickness is less than 5 μm, the initial potential becomes low,
If it exceeds 50 μm, the sensitivity tends to decrease.

In the electrophotographic photosensitive member of the present invention, the charge generating substance used in the photosensitive layer contains the above phthalocyanine mixed crystal, and in addition to this phthalocyanine mixed crystal, a charge generating substance other than the above phthalocyanine compound, azo It is also possible to use together an organic pigment or the like that generates an electric charge such as a pigment.

The charge-transporting substance used in the photosensitive layer of the electrophotographic photosensitive member of the present invention is, for example, an electron-accepting substance having a negative charge-transporting property such as trinitrofluorenone, tetranitrofluorenone, or the like. Polymers having a heterocyclic compound represented by N-vinylcarbazole in the side chain, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives,
Examples of the electron-donating substance having a positive charge transporting property include a polyarylalkane derivative, a phenylenediamine derivative, a hydrazone derivative, an amino-substituted chalcone derivative, a triarylamino derivative, a carbazole derivative, and a stilbene derivative. The substance is not limited to these.

When the photosensitive layer of the electrophotographic photosensitive member of the present invention is formed by mixing the charge generating substance and the charge transporting substance, the mixing ratio of the charge generating substance and the charge transporting substance containing the above phthalocyanine mixed crystal is included. However, the weight ratio is 1:10 to 1: 2.
It is preferred that

At this time, poly-N- is used as the charge transport material.
When a polymer having a heterocyclic compound such as vinylcarbazole in the side chain is used, the binder resin may or may not be used, but when other substances are used, the binder resin is necessary. The content of the binder resin is 30% by weight or more based on the total amount of the charge transport material and the charge generating material.
It is preferable to set it to 00% by weight or less. When using a binder resin, a plasticizer, a fluidity-imparting agent, a pinhole inhibitor, etc. can be further added, if necessary. When these additives are used, their content is preferably 5% by weight or less with respect to the total amount of the charge generating substance, the charge transporting substance and the binder resin.

When the photosensitive layer of the electrophotographic photosensitive member of the present invention is a function-separated type photosensitive layer comprising a charge generating layer and a charge transporting layer, the charge generating layer contains the phthalocyanine mixed crystal as a charge generating substance. However, as described above, it is also possible to contain an organic pigment or the like that generates an electric charge in addition to the above.
Further, the charge generation layer may contain a binder resin in addition to the above charge generation substance. In this case, it is preferable that the binder resin is contained in an amount of 500% by weight or less based on the amount of the charge generating substance. In addition, the above-mentioned additives (plasticizer,
A fluidity imparting agent, a pinhole inhibitor, etc.) may be added in an amount of 5% by weight or less based on the total amount of the charge generating substance and the binder resin.

The charge transport layer contains the charge transport material as described above. Also in the charge transport layer, the binder resin may be contained in an amount of, for example, 500% by weight or less based on the amount of the charge transport substance. When the charge transport material is a low molecular weight compound or the like, it is preferable that the binder resin is contained in an amount of 50% by weight or more based on the amount of the charge transport material. Further, if necessary, the charge transport layer may contain the above-mentioned additive in an amount of 5% by weight or less based on the total amount of the charge transport substance and the binder resin.

Examples of the binder resin include polycarbonate, polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, styrene-butadiene copolymer,
Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly- Examples thereof include insulating resins such as N-vinylcarbazole, polyvinyl butyral, fluororesins, urethane resins, alkyd resins, epoxy resins and melamine resins, and semiconductive resins such as polyvinylcarbazole and polysilane. Further, a thermosetting resin and a photocurable resin which are crosslinked by heat and / or light can also be used.

As the electrophotographic photosensitive member of the present invention, for example,
When a photosensitive layer containing a charge generating substance and a charge transporting substance is used, the production method thereof includes a charge generating substance containing the phthalocyanine mixed crystal obtained above and a charge transporting substance, if necessary, in a suitable solvent. In addition to the binder resin in, in a usual manner, for example, ball mill, attritor, ultrasonic disperser, homomixer, paint mixer,
Uniformly dissolve or disperse with a kneading disperser such as a sand mill or a disperser, and the obtained photosensitive layer coating liquid is an air doctor coater, blade coater, rod coater, reverse roll coater, spray coater, hot coater, squeeze coater, gravure coater. And the like, and then appropriately dried so as to have a sufficient charging potential as the photosensitive layer to form a photosensitive layer. Further, in this case, depending on the kind of the binder resin used, a curing reaction may be carried out after coating and drying the photosensitive layer coating liquid.

As the solvent used for the photosensitive layer coating liquid,
Charge generating substance, charge transporting substance, binder resin and the like are not particularly limited as long as it can be uniformly dissolved or dispersed, acetone, methyl ethyl ketone, ketone solvents such as cyclohexanone, ether solvents such as tetrahydrofuran, Preferable examples include aromatic solvents such as toluene and xylene, halogenated hydrocarbon solvents such as methylene chloride and carbon tetrachloride, and alcohol solvents such as methanol, ethanol and propanol.

The conductive support used in the electrophotographic photoreceptor of the present invention includes a metal plate, a metal drum or a conductive polymer, a conductive compound such as indium oxide, or a conductive material made of a metal such as aluminum, palladium or gold. Examples thereof include those in which a thin layer is provided on a substrate such as paper, ceramic, plastic or film by means of coating, vapor deposition, laminating and the like. These forms may take any form such as a sheet form, a drum form, a belt form, and a seamless belt form.

When the photosensitive layer of the electrophotographic photosensitive member is a function-separated type composed of a charge generating layer and a charge transporting layer, the charge generating layer and the charge transporting layer are laminated on the conductive support with the upper layer being the upper layer. Alternatively, the charge generation layer may be sandwiched between charge transport layers to form a photosensitive layer. The method of forming each layer on a conductive support is such that the photosensitive layer contains a charge generation substance and a charge transport substance. A method similar to the case of using can be used.

[0039]

The present invention will be described below with reference to examples. First, a production example of the phthalocyanine mixed crystal used in the present invention will be described.

[0040]

[Production Example 1] (Production of titanyl phthalocyanine) 58 g of 1,3-diiminoisoindoline and 51 g of tetrabutoxytitanium were mixed with α
After the reaction in 300 mL of -chloronaphthalene at 210 ° C for 5 hours, α-chloronaphthalene and dimethylformamide (DMF) were washed in this order. After that, hot DMF, hot water,
It was washed with methanol and dried to obtain 51 g of titanyl phthalocyanine. (Production of hydrogen phthalocyanine) After reacting 58 g of 1,3-diiminoisoindoline in 300 mL of α-chloronaphthalene at 210 ° C. for 5 hours, α-chloronaphthalene, D
It was washed in order of MF. Then, it was washed with hot DMF, hot water and methanol and dried to obtain 42 g of hydrogen phthalocyanine.

Using the titanyl phthalocyanine and hydrogen phthalocyanine thus obtained as raw materials, the following phthalocyanine mixed crystal was produced. (Production Example Phthalocyanine mixed crystal) 4 g of the above-obtained titanyl phthalocyanine and 0.9 mol of hydrogen phthalocyanine were prepared so that the mole fraction of titanyl phthalocyanine was 80%.
and g were added to 400 g of sulfuric acid cooled to 0 ° C., and subsequently stirred at 0 ° C. for 1 hour. After confirming that the phthalocyanine was completely dissolved, it was added to a water 800 mL / toluene 800 mL mixed solution cooled to 0 ° C. After stirring at room temperature for 2 hours, the precipitated phthalocyanine mixed crystal was filtered from the mixed solution and washed with methanol and water in this order. After confirming the neutrality of the wash water, the phthalocyanine mixed crystal was filtered off from the wash water,
After drying, 4.4 g of a phthalocyanine mixed crystal was obtained.

The X-ray diffraction spectrum of this mixed crystal is shown in FIG. Bragg angle (2θ ± 0.2 °) 6.8 °, 7.4
It has peaks at 15.0 °, 24.7 °, 26.2 °, 27.2 °, and the ratio of the peak intensity at 27.2 ° to the peak intensity at 6.8 ° is 5.2. It can be seen that this is a certain phthalocyanine mixed crystal of the present invention. <X-ray diffraction measurement conditions> Model: JEOL JDX-3500 target: Cu Kα ray tube voltage: 40 kV tube current: 200 mA Divergence slit: 1 ° Scattering slit: 1 ° Light receiving slit: 0.2 mm Step angle: 0.06 ° Counting time: 1 second or less, all X-ray diffraction measurements were performed under the same conditions.

For comparison, the following titanyl phthalocyanine crystal and a comparative phthalocyanine mixed crystal were produced. (Titanyl phthalocyanine crystal) The same treatment as in the production example of the above phthalocyanine crystal was performed except that 4 g of the titanyl phthalocyanine obtained above was used as a raw material to obtain 3.1 g of a titanyl phthalocyanine crystal. The X-ray diffraction spectrum of this titanyl phthalocyanine crystal is shown in FIG. Bragg angle (2θ ± 0.2 °) 7.3
It has peaks at °, 14.9 ° and 27.2 °, but 6.
It has no peaks at 8 °, 24.7 °, and 26.2 °, which is different from the phthalocyanine mixed crystal of the present invention. (Hydrogen phthalocyanine crystal) A hydrogen phthalocyanine crystal (3.0 g) was obtained by performing the same treatment as in the production example of the phthalocyanine mixed crystal except that 4 g of the hydrogen phthalocyanine obtained above was used as a raw material. The X-ray diffraction spectrum of this hydrogen phthalocyanine crystal is shown in FIG. Bragg angle (2θ ± 0.2 °) 6.8 °, 7.4 °, 14.
It has peaks at 9 °, 24.7 ° and 26.2 °, but 2
It has no peak at 7.2 °, which is different from the phthalocyanine mixed crystal of the present invention. Comparative Example Phthalocyanine Mixed Crystal The titanyl phthalocyanine had a mole fraction of 80% except that 1.0 g of titanyl phthalocyanine and 4.0 g of hydrogen phthalocyanine were used as raw materials so that the mole fraction of titanyl phthalocyanine was 20%. The same treatment as in the production example of the phthalocyanine mixed crystal was performed to obtain 4.3 g of the phthalocyanine mixed crystal. The X-ray diffraction spectrum of this mixed crystal is shown in FIG. Bragg angle (2θ ± 0.2 °) 6.8 °, 7.4 °, 1
It has peaks at 5.0 °, 24.7 °, 26.2 °, and 27.2 °, but has a peak intensity of 2 at 6.8 °.
The peak intensity ratio at 7.2 ° is 0.5, which is different from the phthalocyanine mixed crystal of the present invention. The obtained phthalocyanine mixed crystal having a titanyl phthalocyanine mole fraction of 20% is hereinafter referred to as Comparative Example phthalocyanine mixed crystal.

[0044]

[Production Example 2] The molar fraction of titanyl phthalocyanine was 80.
% So that the above-obtained titanyl phthalocyanine 4 g and hydrogen phthalocyanine 0.9 g are added to sulfuric acid 400 g.
It was added to the mixture and completely dissolved at 0 ° C. Then add 2 parts of this acid solution
After adding dropwise to 1500 mL of ethanol at 5 ° C, 1
Stirred for hours. Then, this was filtered, washed with water until the filtrate became neutral, and dried to obtain 4.2 g of a phthalocyanine mixed crystal. The X-ray diffraction spectrum of this mixed crystal is shown in FIG. Bragg angle (2θ ± 0.2 °) 6.8 °,
7.4 °, 15.0 °, 24.7 °, 26.2 °, 2
It has a peak at 7.2 ° and the ratio of the peak intensity at 27.2 ° to the peak intensity at 6.8 ° is 5.
It can be seen that it is the phthalocyanine mixed crystal of the present invention which is 2.

[0045]

[Production Example 3] The molar fraction of titanyl phthalocyanine was 70.
% So that the above-obtained titanyl phthalocyanine (3.5 g) and hydrogen phthalocyanine (1.3 g) are mixed with sulfuric acid (40%).
It was added to 0 g and completely dissolved at 0 ° C. Next, this acid solution was added dropwise to 800 mL of water and 2400 g of ice water, and the mixture was stirred at room temperature for 1 hour, filtered, and washed with sufficient water until the filtrate became neutral. This wet paste was added to 300 mL of dichloroethane and stirred at room temperature for 2 hours. Then, the mixture was filtered and washed with water until the filtrate became neutral to obtain 4.0 g of a phthalocyanine mixed crystal. The X-ray diffraction spectrum of this mixed crystal is shown in FIG. Bragg angle (2θ
± 0.2 °) 6.8 °, 7.4 °, 15.0 °, 24.
A phthalocyanine mixed crystal of the present invention having peaks at 7 °, 26.2 ° and 27.2 ° and having a ratio of the peak intensity at 27.2 ° to the peak intensity at 6.8 ° of 3.5. I understand.

[0046]

[Production Example 4] The molar fraction of titanyl phthalocyanine was 90.
% Of the titanyl phthalocyanine obtained above and 0.2 g of hydrogen phthalocyanine in 40% sulfuric acid
It was added to 0 g and completely dissolved at 0 ° C. Next, this acid solution was added dropwise to 800 mL of water and 2400 g of ice water, and the mixture was stirred at room temperature for 1 hour, filtered, and washed with sufficient water until the filtrate became neutral. This wet paste was added to 300 mL of dichloroethane and stirred at room temperature for 2 hours. Then, it was filtered and washed with water until the filtrate became neutral to obtain 4.2 g of a phthalocyanine mixed crystal. The X-ray diffraction spectrum of this mixed crystal shows the Bragg angle (2θ ± 0.2
゜) 6.8 °, 7.4 °, 15.0 °, 24.7 °, 2
It has peaks at 6.2 ° and 27.2 °, and the ratio of the peak intensity at 27.2 ° to the peak intensity at 6.8 ° is 14, indicating that the phthalocyanine mixed crystal of the present invention is obtained.

[0047]

Examples 1 to 7 Using the phthalocyanine mixed crystal obtained in each of the above Production Examples as a charge generating substance, the following method was used.
Two aluminum plates (conductive support) with a charge generation layer were prepared for each phthalocyanine mixed crystal of each production example.

50 mg of the phthalocyanine mixed crystal and 50 mg of polycarbonate "Iupilon E-2000" (manufactured by Mitsubishi Gas Chemical Co., Inc.) were added to 2.5 mL of tetrahydrofuran, and dispersed by a ball mill for 12 hours. This dispersion was applied onto an aluminum plate so that the film thickness when dried was 1 μm, and 5
After drying at 0 ° C., it was used as a charge generation layer.

Next, p-diethylaminobenzaldehyde diphenylhydrazone or 2,5 as a charge-transporting substance is formed on the charge-generating layer of the aluminum plate with the charge-generating layer.
-Bis (p-diethylaminophenyl) -1,3,4-
A charge-transporting layer was applied using oxadiazole by the following method to prepare seven types of electrophotographic photosensitive members having the configurations shown in Table 1.

200 mg of charge-transporting substance and polycarbonate "Iupilon E-2000" (manufactured by Mitsubishi Gas Chemical Company) 2
A solution prepared by dissolving 00 mg in 2.5 mL of tetrahydrofuran was applied so that the film thickness when dried was 15 μm,
It was dried at 50 ° C. to form a charge transport layer.

Similarly, a comparative electrophotographic photosensitive member using a titanyl phthalocyanine crystal, a metal-free phthalocyanine crystal, and a comparative phthalocyanine mixed crystal was prepared.

[0052]

[Table 1]

<Evaluation of Electrophotographic Photosensitive Member of the Present Invention> The electrophotographic characteristic of each photosensitive member obtained above was evaluated using a photosensitive member evaluation device (Cynthia-55, manufactured by Gentec).

First, the photoconductor was corona charged at a voltage of -6.0 kV, kept in the dark for 1 second to measure the initial surface potential, and then the xenon lamp light was dispersed using a monochromator to obtain a monochromatic light of 780 nm. Exposed with, the initial surface potential is 1
The time until it attenuated to / 2 was measured, and the sensitivity (E _1/2 (μJ / cm ² )) was obtained from the product of the intensity of incident light. The results are shown in the rightmost column of Table 1.

From these results, the electrophotographic photosensitive member of the comparative example has a large E _1/2 value at 780 nm of 1.8 or more, which is not very sensitive, whereas the electrophotographic photosensitive member of the present invention has 78.
It can be seen that the value of E _1/2 at 0 nm is as small as 0.7 or less and the sensitivity is very good.

[0056]

The electrophotographic photosensitive member of the present invention has a thickness of 780 nm.
Since it has high sensitivity in the long wavelength region before and after, it exhibits an excellent effect especially when used in a laser printer.
Further, since the phthalocyanine mixed crystal used as the charge generating substance is a crystal with good stability, it is possible to obtain an electrophotographic photoreceptor having excellent durability and storage stability. Further, this also improves the storage stability of the coating liquid for the photosensitive layer of the electrophotographic photosensitive member.

[Brief description of drawings]

FIG. 1 is a diagram showing an X-ray diffraction spectrum of a phthalocyanine mixed crystal of Production Example 1.

FIG. 2 is a diagram showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal.

FIG. 3 is a diagram showing an X-ray diffraction spectrum of a hydrogen phthalocyanine crystal.

FIG. 4 is a diagram showing an X-ray diffraction spectrum of a phthalocyanine mixed crystal of Comparative Example.

5 is a view showing an X-ray diffraction spectrum of a phthalocyanine crystal body of Production Example 2. FIG.

FIG. 6 is a view showing an X-ray diffraction spectrum of a phthalocyanine mixed crystal of Production Example 3.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuyuki Shigematsu 1000, Higashihuinana-cho, Ushiku-shi, Ibaraki Mitsubishi Chemical Co., Ltd. Tsukuba Plant

Claims (1)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and a photosensitive layer containing a charge transport substance and a charge generating substance, wherein the charge generating substance comprises titanyl phthalocyanine and hydrogen phthalocyanine, and X-ray Bragg angle (2θ ± 0.2 °) 6.8 ° in diffraction spectrum, 7.
4 °, 15.0 °, 24.7 °, 26.2 °, 27.2
An electrophotographic photoreceptor containing a phthalocyanine mixed crystal having a peak at 6 ° and a ratio of the peak intensity at 27.2 ° to the peak intensity at 6.8 ° of 1 or more.