JPH0786692B2 - Photoconductor - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor, for example, a photoconductor for electrophotography, and more particularly to a photoconductor which is used in a printer, a copying machine or the like and has high sensitivity to light having a wavelength longer than visible light and semiconductor laser light. Is.

B. 2. Description of the Related Art Conventionally, electrophotographic photoconductors having photosensitivity to visible light have been widely used in copying machines, printers and the like. As such an electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer containing an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide as a main component is widely used. However, such an inorganic photoreceptor is not always satisfactory in the characteristics such as photosensitivity, thermal stability, moisture resistance and durability required for an electrophotographic photoreceptor of a copying machine or the like. For example, selenium crystallizes due to heat or stains on fingerprints when it is touched with a hand, so that the above characteristics as an electrophotographic photoreceptor are likely to deteriorate. Further, the electrophotographic photoreceptor using cadmium sulfide is inferior in moisture resistance and durability, and the electrophotographic photoreceptor using zinc oxide has a problem in durability. In addition, the electrophotographic photoreceptor of selenium and cadmium sulfide has a drawback that there are great restrictions in terms of production and handling.

In order to improve such problems of inorganic photoconductive substances, it has been attempted to use various organic photoconductive substances in the photosensitive layer of electrophotographic photoreceptors, and research and development have been actively conducted in recent years. ing. For example, in Japanese Examined Patent Publication No. 50-10496,
Poly-N-vinylcarbazole and 2,4,7-trinitro-
An organophotoreceptor having a photosensitive layer containing 9-fluorenone is described. However, this photoreceptor is also insufficient in sensitivity and durability. Therefore, a function-separated electrophotographic photosensitive member has been developed in which the photosensitive layer is divided into two layers, the carrier generating layer and the carrier transporting layer are separately configured, and the carrier generating substance and the carrier transporting substance are contained in each. This is because the substances capable of generating a carrier and the function of transporting a carrier can be separately assigned to different substances, and therefore substances exhibiting each function can be selected from a wide range, so that an electrophotographic photosensitive material having arbitrary characteristics can be selected. The body is relatively easy to get. Therefore, it is expected that an organic photoreceptor having high sensitivity and high durability can be obtained.

As a carrier generating substance effective for the carrier generating layer of such a function-separated type electrophotographic photosensitive member, many substances have been proposed in the past. An example of using an inorganic substance is amorphous selenium as described in JP-B-43-16198. This carrier generation layer containing amorphous selenium is used in combination with the carrier transport layer containing an organic carrier transport substance. However, the carrier generation layer made of amorphous selenium has a problem that it is crystallized by heat or the like and its characteristics are deteriorated as described above. Examples of using an organic substance as the carrier generating substance include organic dyes and organic pigments. For example, those having a photosensitive layer containing a bisazo compound are disclosed in JP-A-47-37543 and JP-A-55-22834.
It is already known from Japanese Patent Laid-Open No. 54-79632 and Japanese Patent Laid-Open No. 56-116040.

However, although these known bisazo compounds have relatively good sensitivity in the short wavelength region or the medium wavelength region, they have low sensitivity in the long wavelength region and are used in a laser printer using a semiconductor laser light source expected to have high reliability. It was difficult.

At present, gallium-aluminum-arsenic (Ga.Al.As) based light emitting devices that are widely used as semiconductor lasers have an oscillation wavelength of about 750 nm or more. In order to obtain an electrophotographic photosensitive member having high sensitivity to such long-wavelength light, many studies have been made in the past. For example, Se having a high sensitivity in the visible light region, a method of adding a sensitizer for newly lengthening the wavelength of the photosensitive material such as CdS was considered, but Se and CdS are temperature and humidity as described above. There is still a problem because the environment resistance to such things is not sufficient. In addition, the sensitivity of many known organic photoconductive materials is usually limited to the visible light region of 700 nm or less as described above, and few materials have sufficient sensitivity in the longer wavelength region.

Of these, it is known that the phthalocyanine compound, which is one of the organic photoconductive materials, has a light-sensitive region expanded to a long wavelength region as compared with other compounds. Examples of these phthalocyanine compounds exhibiting photoconductivity include those disclosed in JP-A-61
Examples of the α-type titanyl phthalocyanine described in JP-A-239248. As shown in FIG. 2, this α-type titanyl phthalocyanine has peaks at a Bragg angle of 7.5, 12.3, 16.3, 25.3 and 28.7 with respect to X-ray of CuKα1.541Å. However, this α-type titanyl phthalocyanine has a low sensitivity and is inferior in potential stability against repeated use, and there is a problem that the fog is likely to occur in the electrophotographic process using the inversion phenomenon. Further, since the charging ability is poor, it is difficult to obtain a sufficient image density.

By the way, generally, in a photoreceptor, a carrier-transporting substance effective for a specific carrier-generating substance is not always effective for another carrier-generating substance, and conversely for a specific carrier-transporting substance. It cannot be said that an effective carrier generating substance is also effective for other carrier transporting substances. After all, in order to be used in the electrophotographic photoreceptor, a proper combination of both the carrier-generating substance and the carrier-transporting substance is necessary. If this combination is inappropriate, the sensitivity of the electrophotographic photoreceptor is increased. Not only becomes low, but also the discharge efficiency is low especially in a low electric field, so that the so-called residual potential becomes large, and in the worst case, when the electrophotographic photoreceptor is used in a copying machine, for example, it is repeatedly used. The electric charge may be accumulated every time the toner is charged, so that the toner may adhere to the non-image portion to cause the smear of the copy, or a clear copy image may not be obtained.

Thus, the combination of the carrier-generating substance and the carrier-transporting substance is important, but there is not necessarily a general law selection method for this combination, and it is necessary to find a carrier-transporting substance suitable for a specific carrier-generating substance. Is difficult.

C. As described above, as the organic carrier generating substance having sensitivity in the long wavelength region, a phthalocyanine compound can be mentioned.
The α-type titanyl phthalocyanine has problems in its production method and potential stability when it is repeatedly used as an electrophotographic photoreceptor.

Therefore, a first object of the present invention is to provide a photoconductor using titanyl phthalocyanine, which has high sensitivity especially to light having a wavelength of 600 nm or more.

A second object of the present invention is to provide a photoreceptor using a carrier-transporting material suitable for the above titanyl phthalocyanine.

A third object of the present invention is to provide a photoreceptor having high potential stability by repeated use.

A fourth object of the present invention is to provide a photoconductor having excellent charging ability.

A fifth object of the present invention is to provide a photoconductor most suitable for the reversal development process.

D. Structure of the Invention and Its Effect The present invention provides a compound represented by the following general formula [I] and titanyl phthalocyanine having a maximum Bragg angle 2θ of 27.3 ° ± 0.2 ° with respect to CuKα characteristic X-ray (wavelength 1.541Å). The present invention relates to an electrophotographic photosensitive member having a photosensitive layer contained therein.

General formula [I] (However, in this general formula, R ¹ represents a hydrogen atom, an allyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ² , R ³ , and R ⁴ are each a hydrogen atom. Represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group, m and l each represent an integer of 1 or 2, and n represents 0.
Or represents an integer of 1. In the above R ^{1 to} R ⁴ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and the like. The “substituted alkyl group” includes a substituted or unsubstituted aralkyl group, and examples of the aralkyl group include a benzyl group and a phenethyl group.

Examples of the aryl group for R ¹ include a phenyl group and the like.

Examples of the alkoxy group in R ² , R ³ and R ⁴ include a methoxy group, an ethoxy group and a butoxy group.
The “substituted alkoxy group” includes a substituted or unsubstituted arylalkoxy group, and examples of the arylalkoxy group include a benzyloxy group and a phenethyloxy group. Examples of the aryloxy group include a phenoxy group and the like.

The photoconductor of the present invention has a remarkable feature in that the specific titanyl phthalocyanine having the main peak of the Bragg angle is used as the carrier generating substance.

That is, the titanyl phthalocyanine has a high sensitivity to light having a wavelength of 600 nm or more, as described later, and the maximum value of its photosensitive wavelength range is 817 nm ± 5 nm.
Therefore, by adopting the above-mentioned titanyl phthalocyanine, it is possible to obtain a photoreceptor having high sensitivity to light in a long wavelength region such as a light emitting diode and a semiconductor laser. Further, since the titanyl phthalocyanine has excellent charging ability, it is possible to obtain a sufficient image density, and also excellent in potential stability against repeated use, and it is difficult for fog to occur even in an electrophotographic process using reversal development. . Furthermore, the above-mentioned titanyl phthalocyanine has an extremely stable crystal form, is unlikely to cause transition to another crystal form, and has excellent crystal stability against solvent, heat and mechanical strain. Therefore, as described above, it is not only excellent in the characteristics upon repeated use, but also advantageous in adjusting titanyl phthalocyanine, and has a great advantage in the production of an electrophotographic photoreceptor and its use.

Further, the photoreceptor of the present invention is characterized in that it contains the hydrazone compound represented by the above general formula [I] as a carrier transporting substance.

That is, when the combination of the carrier-generating substance and the carrier-transporting substance is inappropriate, the sensitivity is lowered, the residual potential is increased, and the potential stability during repeated use is lowered. Moreover, it is considered that there is no general law for selecting the above-mentioned combination, and the fact is that an advantageous combination is practically determined from a large number of substance groups.

Here, the present inventor has found that when the above-mentioned titanyl phthalocyanine compound is used as a carrier-generating substance in a photoreceptor, if the hydrazone compound is selected as a carrier-transporting substance, a photoreceptor having good properties can be obtained. Of.

That is, if the carrier transporting substance of the present invention is selected, carrier injection from the carrier generating substance to the carrier transporting substance is performed smoothly, probably because the ionization potential is compatible with the titanyl phthalocyanine of the present invention. It is possible to enjoy good residual potential characteristics, sensitivity characteristics upon repeated use, and charging potential characteristics.

Further, the hydrazone compound represented by the above general formula [I] according to the present invention has excellent compatibility with various polymer binders, and even if the amount thereof relative to the polymer binder is increased, turbidity and opacity occur. Therefore, the mixing range of the polymer binder can be made very wide, so that a photoreceptor having favorable carrier transporting performance and physical properties can be prepared. Since the compatibility is excellent, the carrier transport phase is uniform and stable, and as a result, it is possible to obtain a photoreceptor having high sensitivity and capable of forming a clear image without sensitivity, charging characteristics and fog. In addition, when it is used for repetitive transfer type electrophotography, it is possible to obtain the effect that fatigue deterioration does not occur.

Further, the carrier transport material of the present invention is safe, environmentally preferable, and scientifically stable.

As described above, according to the present invention, it is possible to provide a photoreceptor having high sensitivity to long-wavelength light, high potential stability due to repeated use, and excellent chargeability in a reversal development process.

In the photosensitive layer constituting the photoreceptor of the present invention, it is preferable that the granular carrier generating substance and the carrier transporting substance are bound by the binder substance (that is, dispersed in the form of pigment in the layer). . In this case, the printing durability and durability of the layer are improved, the memory phenomenon is small, and the residual potential is stable.

The titanyl phthalocyanine according to the present invention is used as a carrier generating substance when used as a function-separated type electrophotographic photoconductor, and is combined with a carrier transporting substance to form a photoconductor. This titanyl phthalocyanine according to the present invention is different from the above-mentioned α-type titanyl phthalocyanine, and as shown in FIG. 1, CuKα1.5
Bragg angle for 41Å X-ray (error 2θ ± 0.2 degrees)
Has an X-ray diffraction spectrum having major peaks at 9.5, 9.7, 11.7, 15.0, 23.5, 24.1 and 27.3. The Bragg angles of CuKα1.541Å of α-type titanyl phthalocyanine for X-rays are 7.5, 12.3, 16.3, 25.3, 2 as described above.
Since it is 8.7, it has a completely different crystal form from the α form.

The titanyl phthalocyanine according to the present invention exhibits a unique spectrum as described above, but its basic structure is represented by the following general formula.

(However, X ¹ , X ² , X ³ , and X ⁴ represent Cl or Br, and a, b,
c and d represent the integer of 0-4. The X-ray diffraction spectrum is measured under the following conditions (the same applies hereinafter).

X-ray tube Cu voltage 40.0 KV current 100.0 mA start angle 6.00 deg. Stop angle 35.00 deg. Step angle 0.020 deg. Measurement time 0.50 sec. The method for producing titanyl phthalocyanine according to the present invention will be exemplified.

First, for example, titanium tetrachloride and phthalodinitrile are α-
The reaction is carried out in a chloronaphthalene solvent, and dichlorotitanium phthalocyanine (TiCl ₂ Pc) thus obtained is hydrolyzed with aqueous ammonia or the like to obtain α-type titanyl phthalocyanine. This is preferably subsequently treated with an electron donating solvent such as 2-ethoxyethanol, diglyme, dioxane, tetrahydrofuran, N, N-dimethylformamide, N-methylpyrrolidone, pyridine, morpholine.

Next, the α-type titanyl phthalocyanine was added at 50 to 180 ° C,
Preferably, the titanyl phthalocyanine of the present invention is produced by stirring or milling at a temperature of 60 to 130 ° C. for a time sufficient for crystal conversion and with mechanical strain.

As another method for producing the above α-type titanyl phthalocyanine, TiCl ₂ Pc is preferably dissolved once in sulfuric acid at 5 ° C. or below or made into a sulfuric acid salt, poured into water or ice water, and reprecipitated or hydrolyzed. , Α-type titanyl phthalocyanine is obtained.

The titanyl phthalocyanine obtained as described above is
It is preferable to use it in a dry state, but it is also possible to use a water paste. The dispersion medium for stirring and kneading may be one normally used for dispersion of pigments or emulsion mixing,
Examples thereof include glass beads, steel beads, alumina beads, and flint stone. However, the dispersion medium is not always necessary. As the grinding aid, those usually used as a grinding aid for pigments may be used, and examples thereof include common salt, sodium bicarbonate, and sodium sulfate. However, this grinding aid is not always necessary.

When a solvent is required at the time of stirring, kneading, and grinding, it may be liquid at the temperature at the time of stirring and kneading, for example, alcohol solvent, that is, glycerin, ethylene glycol, diethylene glycol or polyethylene glycol solvent, ethylene glycol monomethyl. ether,
It is preferable to select one or more kinds from the group of cellosolve-based solvents such as ethylene glycol monoethyl ether, ketone-based solvents, ester ketone-based solvents and the like.

Typical examples of the apparatus used in the crystal transition step include a general stirring apparatus such as a homomixer, a disperser, an agitator, a stirrer or a kneader, a Banbury mixer, a ball mill, a sand mill and an attritor.

The temperature range in the crystal transition step is 50 to 180 ° C, preferably 60 to 130 ° C. It is also effective to use crystal nuclei as in the usual crystal transition process.

Next, the hydrazone compound represented by the general formula [I] will be described.

In the general formula [I], R ¹ is preferably a phenyl group, R ² and R ³ are preferably lower alkyl groups or lower alkoxy groups, and R ⁴ is preferably a hydrogen atom.

The hydrazone compound represented by the general formula [I] can be easily produced by a known method.

For example, the following general formula [II] (In the formula, R ² , R ³ , m, l, and n are the same as those in the general formula [I].) Benzene, toluene, chlorobenzene, alcohol, acetone, N, N- In an organic solvent inert to the reaction, such as dimethylformamide, dimethylsulfoxide, tetrahydrofuran, dioxane, depending on the case, p-toluenesulfonic acid, benzenesulfonic acid, hydrochloric acid, sulfuric acid, potassium acetate,
In the presence of a reaction accelerator such as sodium acetate, the following general formula [III] (In the formula, R ¹ and R ⁴ are the same as above.) And a hydrazine or its hydrochloride or sulfate and 10 to 20
It can be obtained by reacting under a temperature condition of 0 ° C, preferably 20-100 ° C.

Further, acrolein represented by the general formula [II] and the following general formula [IV] (In the formula, R ⁴ is the same as above) and is inactive in the reaction of benzene, toluene, chlorobenzene, alcohol, acetone, N, N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, dioxane and the like. By reacting in a suitable organic solvent in the presence of a reaction accelerator such as p-toluenesulfonic acid, benzenesulfonic acid, hydrochloric acid, sulfuric acid, potassium acetate, sodium acetate, etc., the following general formula [V] (Wherein R ² , R ³ , R ⁴ , m, l and n are the same as those in the above general formula [I]), and then a hydrazone represented by the following general formula [VI] R is prepared. ^1- T ... [VI] (wherein R ¹ is the same as in the general formula [I],
T represents a halogen atom such as a chlorine atom, a bromine atom and an iodine atom. By using an alkylating agent, an allylating agent, an aralkylating agent represented by In an organic solvent inert to the reaction, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, pyridine,
By reacting in the presence of a deoxidizing agent such as trimethylbenzylammonium hydroxide at a temperature of 10 to 200 ° C, the hydrazone compound represented by the general formula [I] can be produced.

One of the raw materials, acrolein, is produced, for example, by the following known reaction.

Specific examples of the hydrazone compound represented by the general formula [I] include, but are not limited to, those having the following structural formulas.

In the present invention, in addition to the above titanyl phthalocyanine, another carrier generating substance may be used in combination. Carrier generating substances that can be used in combination include, for example, α type, β type, γ type,
Examples thereof include X type, τ type, τ ′ type, η type, η ′ type titanyl or metal-free phthalocyanine. In addition, phthalocyanine pigments, azo pigments, anthraquinone pigments, perylene pigments, polycyclic quinone pigments, squalic acid methine pigments, and the like other than the above are also included.

Examples of the azo pigment include the followings.

(VII-5) A-N = N-Ar 1 -CH = CH-Ar 2 -N = N-A (VII-6) A-N = N-Ar 1 -CH = CH-Ar 2 -CH = CH -Ar ³ -N = N
-A (VII-8) A-N = N-Ar ¹ -N = N-Ar ² -N = NA (VII-9) A-N = N-Ar ¹ -N = N-Ar ² -N = N -Ar ³ -N = N
-A (However, in this general formula, Ar ¹ , Ar ² and Ar ³ : are each a substituted or unsubstituted carbocyclic aromatic ring group, R ⁵ , R ⁶ , R ⁷ and R ⁸ are each an electron-withdrawing group. Or a hydrogen atom, at least one of R ^{5 to} R ⁸ is an electron withdrawing group such as a cyano group, (X is a hydroxy group, Or —NHSO ₂ —R ¹² <wherein R ¹⁰ and R ¹¹ are each a hydrogen atom or a substituted or unsubstituted alkyl group, R ¹² is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group>, Y Is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxyl group, a sulfo group, a substituted or unsubstituted carbamoyl group or a substituted or unsubstituted sulfamoyl group (however, when m is 2 or more, , Z may be different groups from each other.), Z is an atomic group necessary for constituting a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring, and R ⁹ is , A hydrogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof, A'is a substituted or unsubstituted ari Le group, p is an integer of 1 or 2, q is an integer of 0-4. )] Further, examples of the polycyclic quinone pigment include compounds of the following general formula [VIII].

General formula [VIII] (In this general formula, X'represents a halogen atom, a nitro group, a cyano group, an acyl group or a carboxyl group, and r is 0 to 4
Represents the integer. ) A concrete example is as follows.

In the photoreceptor of the present invention, as a carrier transporting material that can be used together in the case of function separation type, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives,
Bisimidazolidine derivative, pyrazoline derivative, oxazolone derivative, benzothiazole derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, poly-N-vinylcarbazole, poly-
1-vinylpyrene, poly-9-vinylanthracene and the like can be mentioned.

In order to form the photosensitive layer of the photoreceptor of the present invention, a layer in which the above-mentioned carrier generating substance is dispersed in a binder may be provided on the conductive support. Alternatively, the carrier generating substance and the carrier transporting substance may be combined to provide a laminated or dispersed so-called function-separated photosensitive layer. When the function-separated photosensitive layer is used, it is usually as shown in FIGS. That is, in the layer structure shown in FIG. 6, a carrier generating layer 2 containing titanyl phthalocyanine according to the present invention is formed on a conductive support 1, and a carrier transporting layer 3 containing a carrier transporting substance is laminated on this. A photosensitive layer 4 is formed, and FIG. 7 is a photosensitive layer 4'in which the carrier generating layer 2 and the carrier transporting layer 3 are reversed, and the layer structure of FIG. 8 is shown in FIG. The intermediate layer 5 is provided between the photosensitive layer 4 having the layer structure and the conductive support 1, and FIG. 9 shows the intermediate layer 5 between the photosensitive layer 4 ′ having the layer structure and the conductive support 1 shown in FIG.
Are provided to prevent injection of free electrons into the conductive support 1. The layer structure shown in FIG. 10 is combined with the carrier generating substance 6 mainly containing titanyl phthalocyanine according to the present invention. The photosensitive layer 4 ″ containing the carrier transporting material 7 has been formed.
In the layer structure shown in FIG. 11, the above-mentioned intermediate layer 5 is provided between the photosensitive layer 4 ″ and the conductive support 1.

The carrier generation layer 2 in the case of forming a photosensitive layer having a two-layer structure can be provided by the following method.

(A) A method of applying a solution in which a carrier-generating substance is dissolved in an appropriate solvent or a solution in which a binder is added and mixed and dissolved.

(B) A method in which a carrier-generating substance is made into fine particles in a dispersion medium by a ball mill, a homomixer, etc., and a binder is added as necessary to mix and disperse the resulting dispersion liquid.

In these methods, when the particles are dispersed under the action of ultrasonic waves, uniform dispersion becomes possible.

As the solvent or dispersion medium used for forming the carrier generation layer, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methylethylketone, cyclohexanone, benzene, toluene , Xylene, chloroform,
Examples thereof include 1,2-dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide and the like.

When a binder is used for forming the carrier generating layer or the carrier transporting layer, any binder can be used, but a polymer having a particularly hydrophobic and electrically insulating film forming ability with a high dielectric constant. Polymers are preferred. Examples of such polymers include, but are not limited to, the followings.

a) Polycarbonate b) Polyester c) Methacrylic resin d) Acrylic resin e) Polyvinyl chloride f) Polyvinylidene chloride g) Polystyrene h) Polyvinyl acetate i) Styrene-butadiene copolymer j) Vinylidene chloride-acrylonitrile copolymer k) Vinyl chloride-vinyl acetate copolymer 1) Vinyl chloride-vinyl acetate-maleic anhydride copolymer m) Silicon resin n) Silicon-alkyd resin o) Phenol-formaldehyde resin p) Styrene-alkyd resin q) Poly-N- Vinylcarbazole r) Polyvinyl butyral s) Polycarbonate Z resin These binders can be used alone or as a mixture of two or more kinds. The ratio of the carrier-generating substance to the binder is 10 to 600% by weight, preferably 50.
It is preferable that the content of the carrier-transporting substance be 400 wt% and the carrier-transporting substance be 10-500 wt%.

The thickness of the carrier generation layer 2 thus formed is 0.
It is preferably from 01 to 20 μm, more preferably
It is 0.05 to 5 μm. The thickness of the carrier transport layer is 2-100
μm, preferably 5 to 300 μm.

In the case of forming the photosensitive layer by dispersing the carrier-generating substance, the carrier-generating substance is 2 μm or less,
It is preferable that the particles have an average particle diameter of 1 μm or less. That is, if the particle size is too large, the dispersion in the layer becomes poor, and the particles partially project on the surface to deteriorate the smoothness of the surface, and in some cases discharge occurs at the projecting part of the particle, or there is Toner particles tend to adhere to cause a toner filming phenomenon. A carrier-generating substance that is sensitive to long-wavelength light (up to 700 nm) has a large particle size because the surface charge is neutralized by the generation of thermally excited carriers in the carrier-generating substance. It seems that the neutralizing effect is great. Therefore, high resistance and high sensitivity can be achieved only by reducing the particle size.

Further, the photosensitive layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential or reducing fatigue during repeated use. Examples of electron-accepting substances that can be used here include succinic anhydride, maleic anhydride, dibromosuccinic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3-nitrophthalic anhydride, and 4-nitrophthalic anhydride. Nitrophthalic anhydride, Pyromellitic anhydride, Mellitic anhydride, Tetracyanoethylene, Tetracyanoquinodimethane, o-
Dinitrobenzene, m-dinitrobenzene, 1,3,5-
Trinitrobenzene, paranitrobenzonitrile, picryl chloride, quinone chlorimide, chloranil, bulmannyl, dichlorodicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, 9-phenylenoylidene- [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene- [dicyano Methylene malonodinitrile], picric acid, o-nitrobenzoic acid, p
-Nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, mellitic acid, and other compounds having a high electron affinity can be mentioned. The addition ratio of the electron-accepting substance is the carrier generating substance by weight ratio:
The electron-accepting substance is 100: 0.01-200, preferably 100: 0.1-
Is 100.

The support 1 on which the photosensitive layer is to be provided is a metal plate, a metal drum or a conductive polymer, a conductive compound such as indium oxide, or a conductive thin layer made of a metal such as aluminum, palladium, or gold is applied, vapor-deposited, What is provided on a substrate such as paper or plastic film by means of lamination or the like is used. The intermediate layer functioning as an adhesive layer or a barrier layer is composed of a polymer such as the above-mentioned binder resin, an organic polymer such as polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose or aluminum oxide. Used.

E. Examples Hereinafter, examples of the present invention will be described. First, Synthesis Example 1 of the titanyl phthalocyanine according to the present invention and Synthesis Examples 2 and 3 of the α-type titanyl phthalocyanine of Comparative Example are shown.

(Synthesis Example 1) 10 parts of α-type titanyl phthalocyanine, 5 to 20 parts of salt as a grinding aid, and 10 parts of (polyethylene glycol) as a dispersion medium were put in a sand grinder, and the temperature was 60 ° C to 120 ° C.
It was ground for 7 to 15 hours. In this case, if the graining is performed at a high temperature, the β-type crystal form is likely to be exhibited and the decomposition is likely to occur. After taking out from the container and removing the grinding aid and the dispersion medium with water and methanol, the product was purified with a 2% dilute sulfuric acid aqueous solution, filtered, washed with water and dried to obtain a clear greenish blue crystal. This crystal was found to be the titanyl phthalocyanine of the present invention in FIG. 1 by X-ray diffraction and infrared spectroscopy.

The infrared absorption spectrum was as shown in FIG. The maximum wavelength (λmax) of the absorption spectrum is 817 nm.
It is at ± 5 nm, which is different from λmax = 830 nm of α-type titanyl phthalocyanine.

(Synthesis Example 2) A mixture of 40 g of phthalodinitrile, 18 g of titanium tetrachloride and 500 ml of α-chloronaphthalene was mixed at 240 to 250 ° C. under a nitrogen stream for 3 days.
The reaction was completed by stirring under heating for a while. Then filter,
The product, dichlorotitanium phthalocyanine, was obtained. A mixture of the obtained dichlorotitanium phthalocyanine and 300 ml of concentrated aqueous ammonia was heated under reflux for 1 hour to obtain 18 g of the target product, titanyl phthalocyanine. The product was thoroughly washed with acetone in a Soxhlet extractor. This product was α-type titanyl phthalocyanine shown in FIG.

(Synthesis Example 3) The titanyl phthalocyanine of Synthesis Example 2 was treated with an acid paste to obtain α-type titanyl phthalocyanine having the spectrum shown in FIG.

<Production of Photoreceptor> Next, production of the photoreceptors of Examples and Comparative Examples will be described.

(Examples 1 to 6) 1 part of the titanyl phthalocyanine of the present invention of Synthesis Example 1, a binder resin for dispersion, a polyvinyl butyral resin ("XYH
L "manufactured by Union Carbide Co., Ltd.) and 100 parts of tetrahydrofuran were dispersed for 15 minutes using an ultrasonic disperser. The obtained dispersion was applied with a wire bar onto a conductive support made of a polyester film on which aluminum was vapor-deposited to form a carrier generation layer having a thickness of 0.2 μm.

On the other hand, the compound (carrier transport substance) 3 shown in Table 1 below
Parts and polycarbonate resin ("Panlite L-1250" manufactured by Teijin Chemicals Ltd.) were dissolved in 30 parts of 1,2-dichloroethane, and the obtained solution was applied onto the carrier generating layer and dried to obtain a thickness. A carrier transporting layer having a thickness of 18 μm was formed, whereby the electrophotographic photosensitive member of the present invention was prepared.

Comparative Example 1 An electrophotographic photosensitive member similar to that of Example 1 was prepared except that the carrier transporting material of Example 1 was replaced by the carrier transporting material having the following structure.

(Comparative Example 2) An electrophotographic photosensitive member similar to that of Example 1 was prepared except that the carrier transporting material having the following structure was used instead of the carrier transporting material of Example 1. As for the spectral sensitivity distribution of this photoconductor, the long wavelength sensitivity was good as shown in FIG.

(Comparative Example 3) In the same manner as in Example 1 except that the carrier-generating substance having the X-ray diffraction spectrum diagram shown in FIG. A comparative photoconductor was prepared.

(Comparative Example 4) In the same manner as in Example 1 except that the carrier-generating substance having the X-ray diffraction spectrum shown in FIG. A comparative photoconductor was prepared.

(Example 7) A vinyl chloride-vinyl acetate-maleic anhydride copolymer (S-REC MF-10, manufactured by Sekisui Chemical Co., Ltd.) having a thickness of 0.1 μm on a polyester laminated with aluminum foil.
m intermediate layer was formed.

Next, the titanyl phthalocyanine of the present invention was ground as a CGM for 24 hours by a ball mill to contain 6% by weight of a polycarbonate resin (Panlite L-1250, manufactured by Teijin Chemicals Ltd.).
Add 1,2-dichloroethane solution to titanyl phthalocyanine /
The polycarbonate resin was added in an amount of 30/100 (weight ratio) and further dispersed by a ball mill for 24 hours. To this dispersion, 75% by weight of the carrier-transporting substance shown in Table 1 below was added with respect to the polycarbonate resin, and further adjusted so that monochlorobenzene / 1,2-dichloroethane = 3/7 (volume ratio). Was coated on the above-mentioned intermediate layer by a spray coating method to form a photosensitive layer having a thickness of 20 μm, and a photoreceptor sample of the present invention was obtained.

Example 8 An intermediate layer exactly the same as in Example 1 was formed on a polyester film laminated with aluminum foil.

Then, the carrier transporting substance / polycarbonate resin (Panlite L-1250, manufactured by Teijin Chemicals) shown in Table 1 below = 60
1,2-dichloroethane solution containing 16.5% by weight of 100/100 (weight ratio) was dip-coated on the intermediate layer, dried, and
A μm thick CTL was obtained.

Next, the titanyl phthalocyanine of the present invention was ground as a CGM by a ball mill for 24 hours, and contained 6% by weight of a polycarbonate resin (Panlite L-1250, manufactured by Teijin Chemicals Ltd.) 1,
The 2-dichloroethane solution was added so that titanyl phthalocyanine / polycarbonate resin = 30/100 (weight ratio), and further dispersed by a ball mill for 24 hours. To this dispersion, 75% by weight of the carrier-transporting substances shown in Table 1 below was added to the polycarbonate resin, and monochlorobenzene was further added to produce monochlorobenzene / 1,2-dichloroethane =
What was prepared so as to have a volume ratio of 3/7 was applied onto the CTL by a spray application method to form a CGL having a thickness of 5 μm to obtain a photoreceptor sample of the present invention.

<Measurement of photoconductor characteristics> Twelve types of photoconductors of Examples 1 to 8 and Comparative Examples 1 to 4 were mounted on a modified machine of a laser printer LP-3010 (manufactured by Konishi Rokusha Kogyo Co., Ltd.), and an initial unexposed portion potential (V _H ), the photosensitive portion potential (V _L ), and the differences ΔV _H and ΔV _L from the initial values of V _H and V _L after 10,000 copies were measured. The photoconductors of Examples 7 and 8 were positively charged. The table shows Δ | V _H | and Δ | V _L |.

In addition, the amount of light required to change the charging potential ± 600 V to ± 300 V
When I ₀ (erg / cm ² ), And

A semiconductor laser (oscillation wavelength: 780 nm) is used as the light source.
Was used.

The formulations and measurement results of each photoconductor are shown in the table below.

The electrophotographic photosensitive member using the carrier-generating substance and carrier-transporting substance of the present invention has good long-wavelength sensitivity, high chargeability, excellent potential stability upon repeated use, and provides a clear image without fog.

On the other hand, the comparative sample has a large decrease in sensitivity and chargeability after repeated use, which causes a decrease in image density and fog.

Next, an example applied to the reversal development process will be described.

The four types of photoconductors of Examples 1 and 2 and Comparative Examples 1 and 3 described above were mounted on a modified machine of a laser printer LP-3010 (manufactured by Konishi Rokusha Kogyo Co., Ltd.), and positive or negative was charged by positive or negative charging, respectively. Reverse development using a two-component developer containing toner,
The image formation was repeated 00 times, and the image density and the amount of black spots on the white background were each set to "◎", "○", and "x".
Judgment was made at each stage, and the results are shown in Table 2 below. A semiconductor laser (780 nm) and LED (680 nm) are used as the light source.
Was used.

However, the amount of black spots was 0 / cm ² ○ 3 / cm ² or less × 3 / cm ² or more The image density was measured with a Sakura Densitometer PDA-65 type.

⊚ Reflection density of 1.0 or more ○ 〃 0.6 to 1.0 × 〃 0.6 or less As described above, the photoreceptor according to the present invention is suitable for reversal development.

Also, the same procedure was performed using the following compounds (A) to (H) instead of the carrier transporting substance I-1 in Example 1.
These are Comparative Examples 5 to 12.

Also, instead of the carrier generating substance in Example 1, the carrier generating substance (oxytitanium phthalocyanine) described in Production Example 1 in JP-A-62-67094 was used in the same manner. This is Comparative Example 13.

The photoconductor thus obtained is used as a laser printer LP.
Attached to a modified model of -3010, the initial unexposed area potential (V _H ),
Absolute value of fluctuation value of exposed portion potential (V _L ) and V _H , V _L after 10,000 copies from the initial value | ΔV _H |, | ΔV _L |, Sλ (V · cm
² / erg), and the results are shown in Table-3.

According to this Table-3, it can be seen that the features of the combination of CGM and CTM of the present invention cannot be achieved by the combination of other CGM and CTM.

[Brief description of drawings]

The drawings illustrate the present invention, and FIG. 1 is an X-ray diffraction diagram of the titanyl phthalocyanine of the present invention, and FIGS. 2 and 3 are X-ray diffraction diagrams of two examples of α-type titanyl phthalocyanine. FIG. 4 is an absorption spectrum of the titanyl phthalocyanine of the present invention. FIG. 5 is a spectral sensitivity diagram of a photoconductor, and FIGS. 6, 7, 8, 9, 10 and 11 show the present invention. FIG. 3 is a cross-sectional view showing a specific example of the layer structure of the electrophotographic photoconductor of FIG. In the drawings, reference numerals 1 ... Conductive support 2 ... Carrier generation layer 3 ... Carrier transport layer 4, 4′4 ″ ... Photosensitive layer 5 ... Intermediate layer.

Claims (2)

[Claims] 1. A photosensitive layer containing titanyl phthalocyanine having a maximum Bragg angle 2θ of 27.3 ° ± 0.2 ° with respect to CuKα characteristic X-rays (wavelength 1.541Å) and a compound represented by the following general formula [I]. An electrophotographic photoreceptor characterized by the above. General formula [I] (However, in this general formula, R ¹ represents a hydrogen atom, an allyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ² , R ³ , and R ⁴ are each a hydrogen atom. Represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group, m and l each represent an integer of 1 or 2, and n represents 0.
Or represents an integer of 1. ] 2. The method according to claim 1, wherein the titanyl phthalocyanine is contained in the charge generation layer, and the compound represented by the general formula [I] is contained in the charge transport layer. Electrophotographic photoreceptor.