JP2687235B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photosensitive member having a photoconductive layer provided on a conductive support.

"Conventional technology" An electrophotographic photosensitive member having photosensitivity to visible light is used in copiers,
It has been developed for application to optical printers and the like. As such an electrophotographic photosensitive member, a photosensitive member mainly containing an inorganic photoconductive substance such as selenium, zinc oxide, and cadmium sulfide has been widely used. However, such an inorganic photoreceptor has performance required for an electrophotographic photoreceptor such as a copying machine, for example, photosensitivity, heat stability, moisture resistance,
It does not always satisfy characteristics such as durability.

For example, the selenium photoconductor is crystallized by heat or stains on fingerprints when it is touched with a hand, so that the above-mentioned characteristics required as an electrophotographic photoconductor are easily deteriorated.

Further, an electrophotographic photosensitive member using cadmium sulfide is inferior in moisture resistance and durability, and an electrophotographic photosensitive member using zinc oxide has a problem in durability such as film strength. In addition, selenium and cadmium sulfide are toxic, and therefore have great restrictions on production or handling.

In recent years, electrophotographic photoreceptors using various organic substances have been studied and developed to eliminate the disadvantages of photoreceptors using these inorganic substances, and some of them have been put to practical use. For example, an electrophotographic photoreceptor comprising poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (U.S. Pat.
No. 484,237), those obtained by sensitizing poly-N-vinyl carbazole with a pyrylium salt dye (Japanese Patent Publication No. 48-25658),
Electrophotographic photoreceptor containing an organic pigment as a main component (JP-A-47-37)
No. 543), and an electrophotographic photoreceptor having a eutectic complex comprising a dye and a resin as a main component (JP-A-47-10785).

However, although these photoreceptors have improved the disadvantages of the inorganic photoreceptors to some extent, they generally have low photosensitivity, are not suitable for repeated use, and do not sufficiently satisfy the requirements as electrophotographic photoreceptors.

In order to remedy such drawbacks, an electrophotographic photoreceptor having a function-separated type photoconductive layer in which the charge generation function and the charge transport function are individually assigned to different substances has been proposed. I'm sorry. The function-separated type electrophotographic photoreceptor expands the selection range of materials, thereby improving the sensitivity, durability, and other characteristics of the electrophotographic photoreceptor. It has the advantage that it can be selected from a wide range.

Various organic dyes and organic pigments have been developed as effective organic charge generating substances used in the charge generation layer of such a function-separated type electrophotographic photoreceptor. For example, azo pigments and perylene pigments having various structures have been developed. And polycyclic quinone pigments, square methine dyes, and the like.

However, these pigments show relatively good sensitivity in the short wavelength or middle wavelength range, but have low sensitivity in the long wavelength range, and can be used for laser printers using semiconductor laser light sources that are expected to have high reliability. It was difficult.
At present, the oscillation wavelength of a potassium-aluminum-arsenic-based light-emitting element widely used as a semiconductor laser is 750 n
m or more.

"Problems to be Solved by the Invention" Phthalocyanine-based compounds, which are one of the organic photoconductive materials, are known to have a sensitivity range expanded to longer wavelengths compared to the pigments and dyes. Insufficient electrophotographic characteristics such as sensitivity, chargeability and the like are observed. In order to improve these drawbacks, various types of phthalocyanine having different central metals or various crystal forms have been developed. In the process of converting an unstable α-form phthalocyanine into a stable β-form crystal form, various crystal forms of phthalocyanine have been found. For example, ε-type copper phthalocyanine, X-type metal-free phthalocyanine, and m-type titanyl phthalocyanine are known. These phthalocyanines have sensitivity in the long wavelength region, but are insufficient in sensitivity for copiers and optical printers, and have drawbacks such as insufficient potential stability or large residual potential in repeated use. However, it could not be put to practical use.

On the other hand, as a method for improving the sensitivity of an electrophotographic photoreceptor containing a phthalocyanine pigment, the addition of a charge transporting compound such as a hydrazone compound or an oxazole compound, or the addition of an electron withdrawing compound such as tetranitrofluorene or trinitrofluorene. Has been tried, but although the sensitizing effect is recognized, the effect is insufficient,
Alternatively, these additives have adverse effects such as a decrease in chargeability, a decrease in potential stability upon repeated use, a decrease in sensitivity, an increase in residual potential, and the like. The electron-withdrawing compound is toxic and cannot be put to practical use.

As can be understood from the above description, the electrophotographic photoreceptor has high sensitivity, particularly high sensitivity to light having a long wavelength of 750 nm or more, has high potential stability in repeated use, and has little decrease in residual potential and sensitivity. The development of was desired.

"Object of the Invention" The object of the present invention is to provide high sensitivity, especially sufficient sensitivity to long wavelength light such as a semiconductor laser, and in repeated use, high potential stability, small residual potential, and durability. It is to provide a high electrophotographic photosensitive member.

"Means for solving the problem" As a result of intensive studies, we have found that the general formula (I) or the general formula (I
It has been discovered that the compound represented by the formula (I) sensitizes a phthalocyanine pigment, and the photoreceptor using the phthalocyanine pigment and the compound represented by the general formula (I) or the general formula (II) can use another pigment. As a result, the present inventors have found that they have superior potential stability and residual potential characteristics in repeated use as compared with the photoreceptor, and have arrived at this patent.

General formula (I) General formula (II) In formulas (I) and (II), Z represents a sulfur atom or an oxygen atom. R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each represent a hydrogen atom, an alkyl group or an aryl group, and may be the same or different. R ¹ and R ² , or R ³
And R ⁴ may be linked together. In formula (I), R ¹ to R ⁴ may be connected to each other to form a bridged ring. R ⁷ is a divalent arylene group, aralkylene group,
It represents a polymethylene group or a branched alkanediyl group.

Further, the monovalent group of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ^{6 and} the divalent group of R ⁷ may be unsubstituted or substituted.

That is, the present invention provides: (1) An electrophotographic photoreceptor having a photoconductive layer provided on a conductive support, wherein the photoconductive layer comprises a phthalocyanine pigment and a compound represented by the above general formula (I) or the general formula (II). An electrophotographic photosensitive member for a copying machine or an optical printer, comprising at least one kind.

(2) In an electrophotographic photoreceptor in which a single-layer photoconductive layer is provided on a conductive support, the photoconductive layer is a phthalocyanine pigment and at least one compound represented by the general formula (I) or the general formula (II). An electrophotographic photoconductor for a copying machine or an optical printer, which comprises:

(3) In an electrophotographic photoreceptor provided with a photoconductive layer having a laminated structure composed of a charge generation layer and a charge transport layer on a conductive support, the charge generation layer comprises a phthalocyanine pigment and the general formula (I) Alternatively, an electrophotographic photoreceptor for a copier or an optical printer, comprising at least one compound represented by the general formula (II).

(4) The electrophotographic photosensitive member for a copying machine or printer according to the above (1) to (3), wherein the light source of the copying machine and the optical printer is a laser beam.

According to the present invention, it is possible to obtain a highly durable electrophotographic photosensitive member having high sensitivity and exhibiting good characteristics in repeated use.

(Specific structure and effect of the present invention) As the phthalocyanine pigment used in the photoconductive layer of the electrophotographic photoreceptor of the present invention, those having different central metals, those having different crystal forms, and those having a substituent on the benzene ring are used. Various phthalocyanine pigments can be used. For example, Japanese Patent Publication No. 44-14106, Japanese Patent Publication No. 45-8102, Japanese Patent Publication No. 46-42511, Japanese Patent Publication No. 46-41212, Japanese Patent Publication No. 49-4338, JP-A-58-182639, JP-A-62-47054, etc. Metal phthalocyanine, JP-A-50-38543, JP-A-50-95852, JP-A-51-108847, Copper phthalocyanine described in JP-A-51-109841, etc., JP-A-59-49544, JP-A-59-166959, JP 62
-275272, JP 62-286059, JP 62-67094, JP 63-364, JP 63-365, JP 63-37163, JP 6
3-57670, JP-A-63-80263, JP-A-63-116158, JP-A-63-198067, etc., titanyl phthalocyanine, JP-A-57-90058, JP-A-62-163060, JP-A-62-163060 133462,
JP-A-62-177069, JP-A-63-73529, JP-A-63-43155
Aluminum phthalocyanine described in JP-A-57-14
6255, JP-A-57-144761, JP-A-57-148747, etc., vanadyl phthalocyanine, JP-A-59-44053, JP-A-59-44053
-128544, JP-A-59-133550, JP-A-59-133551, JP-A-59-174846, JP-A-59-174847, JP-A-60-59354,
JP-A-60-260054, JP-A-60-220958, JP-A-62-22292
54, JP-A-63-17457, JP-A-59-155851, JP-A-63-2
7562, and halogenated metal phthalocyanines described in JP-A-63-56564, but are not limited thereto, and various known phthalocyanines can be used.

As representative phthalocyanine central metals, various metals such as copper, nickel, iron, vanadium, aluminum, gallium, indium, silicon, titanium, magnesium, cobalt, platinum, and germanium, as well as non-metallic phthalocyanines are known. Have been.

The crystal form is confirmed by X-ray crystal diffraction for each metal phthalocyanine and non-metal phthalocyanine. For example, in copper phthalocyanine, α-form, β-form, γ-form
Polymorphs such as type, δ type, ε type, η type, ρ type, and in metal-free phthalocyanine, α type, β type, χ type, τ type and other polymorphs, and in titanyl phthalocyanine, α type, β type Type, m
Molds and other polymorphs are each known. Further, a substituted phthalocyanine in which the benzene ring of phthalocyanine is substituted with a halogen atom such as fluorine, chlorine, or bromine, or an alkyl group, a carboxyl group, an amide group, a sulfonyl group, or another substituent is also known.

Further, phthalocyanine pigments used in the present invention include JP-A-63-233886, JP-A-63-186251, and JP-A-63-186251.
Germanium naphthalocyanine described in 63-72761, etc., JP-A-63-55556, silicon naphthalocyanine described in JP-A-63-141070, JP-A-63-186251, JP-A-64-2061, etc. Tin naphthalocyanine described in JP
63-72761, various metal naphthalocyanines described in JP-A-63-231355 and the like can also be mentioned.

These have different absorption wavelengths and are appropriately used depending on the application, but when used in a laser beam printer or the like having a semiconductor laser as a light source, 780 nm to 830 nm
Phthalocyanine pigments having an absorption in water are preferred.

Next, the compound represented by the general formula (I) or the general formula (II) for improving the photoconductivity of the photoconductive layer using the phthalocyanine pigment will be described.

 Z represents a sulfur atom or an oxygen atom.

In the general formula (I) or the general formula (II), R ¹ , R ² , R ³ , R
^{When any of 4} , R ⁵ and R ⁶ is an alkyl group, examples of the alkyl group include a linear or branched unsubstituted or substituted alkyl group having 1 to 22 carbon atoms.

Examples of the substituent bonded to the alkyl group include a halogen atom (chlorine atom, bromine atom, fluorine atom), a cyano group, a nitro group, a phenyl group, a tolyl group and a tolylfluoromethyl group, and the number of the substituents is 1 From 3 to 3.

When any ^{one of} R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is an aryl group,
Examples of the aryl group include a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, and a substituted or unsubstituted anthranyl group. As the substituent, a halogen atom (chlorine atom, bromine atom, fluorine atom), a cyano group, a nitro group, a trifluoromethyl group, a linear or branched alkyl group having 1 to 5 carbon atoms, a carboxyl group,
Alkoxycarbonyl group, cyano group, nitro group or 1 to 3 halogen atoms (chlorine atom, bromine atom, fluorine atom) substituted (in the case of having 2 or 3 substituents, they may be the same or different from each other). A straight-chain or branched alkyl group having 1 to 5 carbon atoms, a straight-chain or branched alkoxy group having 1 to 5 carbon atoms, and the number of substituents is 1 In the case of 2 to 3 substituents, which may be the same or different from each other.

When R ¹ and R ² , or R ³ and R ⁴ are linked,
Examples thereof include trimethylene, tetramethylene, pentamethylene, and oxydiethylene groups (—CH ₂ —CH ₂ —O—
CH ₂ —CH _{2 —} ) and 1 to 3 of the hydrogen atoms of these divalent groups are halogen atoms (chlorine atom, bromine atom, fluorine atom), cyano group, nitro group, phenyl group, tolyl group, benzyl Examples thereof include a group, a phenethyl group, and a divalent group substituted with a linear or branched alkyl having 1 to 5 carbon atoms. Further, the constituent part of these divalent groups may be a part of the aryl ring or the hetero ring.

When R ⁷ is a divalent arylene group, specific examples thereof include p
-Phenylene group, m-phenylene group, o-phenylene group, 1,4-naphthylene group, 2,3-naphthylene group, 4,4'-
And a biphenylylylene group. In the case of a polymethylene group, a polymethylene group having 1 to 22 carbon atoms can be used.
In the case of branched alkanediyl group, pentylidene group, 1,2
-Dimethylethylene group, 1,3-dimethyltrimethylene group, 1,4-dimethyltetramethylene group, 1,5-dimethylpentamethylene group, 1,6-dimethylhexamethylene group,
Examples thereof include a 1-ethylethylene group and a 1,2-diethylethylene group.

Aralkylene group Is raised.

The arylene group and aralkylene group may be substituted with a substituent. As the substituent, a halogen atom,
Cyano group, nitro group, trifluoromethyl group, carbon number 1
And 5 to 5 alkyl groups.

Next, specific examples of the compound represented by the above general formula are shown below, but the present invention is not limited to these compounds.

The urea and thiourea compounds represented by the general formula (I) or (II) in the present invention are both "J. Chem. So
c. " 1955 , 1573-1581.

It is known that an electrophotographic photosensitive member using a phthalocyanine pigment has an induction effect that delays the decay of the surface potential immediately after light irradiation, and this is a cause of sensitivity deterioration. Although the cause has not been clarified, it is considered that the carrier trap is present on the surface of the phthalocyanine particle and the carrier trapped by the light irradiation causes the carrier trap to be not attenuated during this period. The compound of the present invention is considered to be a sensitizer for reducing the induction effect, shortening the time during which the surface potential does not decay (induction period), and consequently improving the sensitivity.

The use of the compound represented by formula (I) or (II) of the present invention for the purpose of an electrophotographic photoreceptor is disclosed in
The description is given in JP-A-58-65438 and JP-A-58-65439. However, these claim the invention as a sensitizer for further sensitizing the dye-sensitized organic photoconductor, and sensitize the photoreceptor without dye sensitization as in the present invention. No sensational effects are described. Further, the above specification does not disclose the use of a phthalocyanine pigment which is a photoconductive pigment in the present invention. Regarding the use of the photoconductive pigment, there is a description of using ZnO which is an inorganic photoconductive pigment, but these are also known to be effective when the inorganic photoconductor such as ZnO is dye-sensitized. However, the effect of reducing the induction effect peculiar to the phthalocyanine pigment as in the present invention is completely unexpected.

Further, the electrophotographic photoreceptors described in JP-A-58-65438 and JP-A-58-65439 show good electrophotographic characteristics when they are used only once, but when they are repeatedly used several times, they are significantly charged. It causes a decrease in the photosensitivity, a decrease in the sensitivity, and an increase in the residual potential, and it cannot be used as a photoreceptor for a copier and an optical printer which are used repeatedly.

Also, when various additives such as tetranitrofluorene and tetracyanoethylene are added for the purpose of increasing the sensitivity of phthalocyanine, the chargeability is reduced and the charge potential is reduced and the residual potential is increased upon repeated use. Is generated.

However, the compound represented by the general formula (I) or the general formula (II) of the present invention sensitizes phthalocyanine without causing the deterioration of the above repeating characteristics, and thus has high sensitivity and good repeatability. Suitable for use in photoconductors for copiers and optical printers that require

The electrophotographic photoreceptor of the present invention has a photoconductive layer containing the phthalocyanine pigment described above and a compound represented by the general formula (I) or (II). Various types of electrophotographic photoreceptors are known, but the electrophotographic photoreceptor of the present invention may be any type of photoreceptor. Usually, the electrophotographic photoreceptor of the present invention is used in a layer constitution type exemplified below.

(1) A single-layer photoconductive layer containing a phthalocyanine pigment and the compound of the formula (I) or (II) is provided on a conductive support.

(2) A structure in which a charge generation layer containing a phthalocyanine pigment and a compound represented by the general formula (I) or (II) is provided on a conductive support, and a charge transport medium layer is provided thereon.

(3) A charge transport medium layer is provided on a conductive support, and a phthalocyanine pigment and a general formula (I) or a general formula (II) are formed thereon.
Provided with a charge generation layer containing a compound represented by the formula:

In order to prepare an electrophotographic photoreceptor of the type (1), a phthalocyanine pigment is dispersed in a solution in which a compound represented by the general formula (I) or the general formula (II) and a binder are dissolved, and this is conductively supported. It may be applied and dried on the body. Alternatively, a coating liquid may be prepared by dispersing a phthalocyanine pigment in a binder solution and then dissolving the compound represented by the general formula (I) in the solution. Type (1)
In the case of the electrophotographic photoreceptor described above, a charge transporting agent described below can be contained in the photoconductive layer for the purpose of assisting the transfer of electric charge, and an electrophotographic photoreceptor having this composition is generally used. At this time, the thickness of the photoconductive layer is preferably 3 to 50 μm, and more preferably 5 to 30 μm.

To prepare an electrophotographic photoreceptor of the type (2), first, a phthalocyanine and a compound of the formula (I) are placed on a conductive support.
Alternatively, the compound represented by the general formula (II) is dispersed in an appropriate solvent or, if necessary, a solvent in which a binder is dissolved, and the resultant is coated and dried to form a charge generation layer. Or,
The coating liquid may be prepared by dispersing the phthalocyanine pigment in a solvent or a solvent in which a binder is dissolved, and then dissolving the compound represented by the general formula (I) or (II). Thereafter, a solution containing a charge transport compound and a binder is coated thereon and dried to provide a charge transport layer. At this time, the thickness of the charge generation layer is 4 μm.
Hereinafter, the thickness is particularly preferably 0.1 to 2 μm, and the thickness of the charge transport layer is preferably 3 to 50 μm, particularly preferably 5 to 30 μm.

Further, the charge generation layer of the present invention is provided with a thin layer containing the compound represented by the general formula (I) or the general formula (II) between the charge generation layer and the conductive support. A charge generation layer of a phthalocyanine pigment is provided, and the phthalocyanine pigment is mixed with the general formula (I) by diffusion of the upper layer coating solvent.
Or a method of containing a compound represented by the general formula (II), or a solution containing a phthalocyanine pigment deposited on a conductive support and containing the compound represented by the general formula (I) or (II) thereon Is applied and coexisted with a phthalocyanine pigment. In this case, the thickness of the phthalocyanine pigment deposited is 0.001 μm or more.
1μ, particularly preferably 0.01μ to 0.5μ, is preferred.

The type (3) electrophotographic photoreceptor is prepared by reversing the stacking order of the type (2) charge generation layer and the charge transport layer.

The type (1) photoreceptor of the present invention has relatively good repetition characteristics because phthalocyanine itself has a charge transfer ability as compared to azo pigments and the like, but the type (2) and (3) photoreceptors Compared to the body, the feeling is low, and the charge potential decreases and the residual potential increases slightly due to repeated use.

Therefore, types (2) and (3) are preferable as the use form of the present invention. In this form, the sensitivity is extremely high, the charge potential does not change much in repeated use, the residual potential is low, and the printing durability is high. Thus, a highly durable electrophotographic photosensitive member can be obtained.

(1) The phthalocyanine pigment used in the photoreceptors of the types (2) and (3) is pulverized and dispersed by a known dispersing machine, for example, a ball mill, a sand mill, a vibration mill or the like. Below, preferably 0.
Used after crushing to 1 to 2μ.

If the amount of the phthalocyanine pigment used in the electrophotographic photoreceptor of the type (1) is too small, the sensitivity is poor. If the amount is too large, the chargeability is deteriorated, and the strength of the electrophotographic photosensitive layer is weakened. The ratio of the phthalocyanine pigment in the layer is 0.01 to 2 times by weight, preferably 0.05 to 1 time by weight, relative to the binder.

When a charge transport compound is used in combination, the ratio of the charge transport compound is 0.1 to 2 times the weight of the binder, preferably 0.3 to 2 times.
A range of about 1.3 times by weight is preferred.

The content of the compound represented by the general formula (I) or the general formula (II) is 0.01 to 1 times the weight of the phthalocyanine pigment,
A range of 0.02 to 0.4 times by weight is preferable.

When the phthalocyanine pigment-containing layer serving as the charge generation layer is formed by coating on the electrophotographic photoreceptors of types (2) and (3), the amount of the phthalocyanine pigment to be used is preferably 0.1 to 50 times by weight, and more preferably less than the binder resin. Sufficient photosensitivity cannot be obtained. The proportion of the charge transport compound in the charge transport medium is 0.01 to 10 times by weight, preferably 0.2 to 2 times by weight the binder.

Also in this case, the content of the compound represented by the general formula (I) or the general formula (II) is appropriately 0.01 to 1 times by weight, preferably 0.02 to 0.4 times by weight, with respect to the phthalocyanine pigment.

In addition, the photosensitive members of the types (2) and (3)
60-196767, JP-A-60-254045, JP-A-60-262159
As described in the respective specifications, a charge transport compound such as a hydrazone compound and an oxime compound may be added to the charge generation layer.

Examples of the charge transport material used in combination with the photosensitive layer of the type (1) used in the present invention include a wide range of known charge transport materials. Charge transport materials can be classified into two types: compounds that transport electrons and compounds that transport holes.

The electron-transporting compound has a compound having an electron-withdrawing group, for example, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 9-
Dicyanomethylene-2,4,7-trinitrofluorenone,
9-dicyanomethylene-2,4,5,7-tetranitrofluorenone, tetranitrocarbazolechloranil, 2,3-
Examples thereof include dichloro-5,6-dicyanobenzoquinone, 2,4,7-trinitro-9,10-phenanthrenequinone, tetrachlorophthalic anhydride, tetracyanoethylene, and tetracyanoquinonedimethane.

As the hole transporting compound, a compound having an electron donating group. For example, in the case of polymers, (1) pyrivinylcarbazole and derivatives thereof described in JP-B-34-10966.

(2) polyvinylpyrene, polyvinylanthracene described in JP-B-43-18674 and JP-B-43-19192;
Poly-2-vinyl- (4'-dimethylaminophenyl)
-5-phenyl-oxazole, poly-3-vinyl-N
-Vinyl polymers such as ethylcarbazole.

(3) Polymers such as polyacenaphthylene, polyindene, and copolymers of acenaphthylene and styrene described in JP-B-43-19193.

(4) Pyrene described in Japanese Patent Publication No. 56-13940
Condensed resins such as formaldehyde resin, bromopyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin.

(5) Various triphenylmethane polymers described in JP-A-56-90883 and JP-A-56-161550.

Alternatively, for low molecular weight compounds, (6) triazole derivatives described in US Pat. No. 3,112,197 and the like.

(7) Oxadiazole derivatives described in U.S. Pat. No. 3,189,447.

(8) An imidazole derivative described in JP-B-37-16096 and the like.

(9) U.S. Patent Nos. 3,615,402 and 3,820,989,
3,542,544, JP-B-45-555, JP-B-51-10983,
JP-A-51-93224, JP-A-55-108667, JP-A-55-1
Polyarylalkane derivatives described in JP-A-56953, JP-A-56-36656, and the gazette.

(10) US Patent No. 3,180,729, US Patent No. 4,278,746
JP-A-55-88064, JP-A-55-880065, JP-A-4
9-105537, JP-A-55-51086, JP-A-56-80051
JP-A-56-88141, JP-A-57-45545, and JP-A-54
-112637, Japanese Patent Application Laid-Open No. 55-74546, publications, and the like, pyrazoline derivatives and pyrazolone derivatives.

(11) U.S. Patent No. 3,615,404, JP-B-51-10105,
JP-A-54-83435, JP-A-54-110836, JP-A-54-1
Phenylenediamine derivatives described in JP 19925, JP-B-46-3712, JP-B-47-28336 and the like;

(12) U.S. Patent No. 3,567,450, Japanese Patent Publication No. 49-35702,
West German Patent (DAS) 1110518, U.S. Patent 3,180,703
No., U.S. Pat.No. 3,240,597, U.S. Pat.No. 3,658,520,
U.S. Pat.No. 4,232,103, U.S. Pat.No. 4,175,961, U.S. Pat.No. 4,012,376, JP-A-55-144250, JP-A-56-1
Arylamine derivatives described in JP-A-19132, JP-B-39-27577 and JP-A-56-22437.

(13) Amino-substituted chalcone derivatives described in US Pat. No. 3,526,501.

(14) N, N described in US Pat. No. 3,542,456
-Bicarbazyl derivatives.

(15) Oxazole derivatives described in U.S. Pat. No. 3,257,203.

(16) Styryl anthracene derivatives described in JP-A-56-46234 and the like.

(17) Fluorenone derivatives described in JP-A-54-110837 and the like.

(18) U.S. Pat. No. 3,717,462, JP-A-54-59143 (corresponding to U.S. Pat. No. 4,150,987), JP-A-55-52063
JP-A-55-52064, JP-A-55-46760, JP-A-55-46760
No. -85495, JP-A-57-11350, JP-A-57-148749,
Hydrazone derivatives disclosed in JP-A-57-104144 and the like.

(19) U.S. Pat. No. 4,047948, U.S. Pat. No. 4,047,949
No., U.S. Pat.No. 4,265,990, U.S. Pat.No. 4,273,846,
Benzidine derivatives described in US Pat. No. 4,229,897 and US Pat. No. 4,306,008.

(20) Stilbene derivatives described in JP-A-58-190953, JP-A-59-95540, JP-A-59-97148, JP-A-59-195658 and the like.

In the present invention, the photoconductive substance is (1) to (20)
The compounds are not limited to those mentioned above, and all known photoconductive substances can be used.

Two or more kinds of these photoconductive substances may be used in combination depending on the case.

Examples of the conductive support used in the electrophotographic photoreceptor of the present invention include a metal plate such as aluminum, copper, zinc, and stainless steel, a metal drum, a sheet of plastic, paper, or the like, or aluminum or oxide oxide on a cylindrical substrate. Paper made by depositing or dispersing a conductive material such as Jum, SnO ₂ , or carbon, or by providing a conductive polymer, or paper that has been conductively treated with an inorganic salt such as sodium chloride or calcium chloride or an organic quaternary ammonium salt. ,
A paper tube, a phenolic resin drum molded by injecting carbon, and a bakelite drum are used.

The resin used for the type (2) and type (3) charge generation layers of the present invention can be selected from a wide range of insulating resins, for example, polyester resin, cellulose resin, acrylic resin, polyamide resin, polyvinyl butyral resin, Phenoxy resin, polyvinyl formal resin, polycarbonate resin, styrene resin, polybutadiene resin, polyurethane resin, epoxy resin, silicone resin,
Examples include, but are not limited to, vinyl chloride resins and vinyl chloride-vinyl acetate resins.

As the resin used for the charge transport layer, it is preferable to use a film-forming high molecular polymer that is hydrophobic, has a high dielectric constant, and is electrically insulating.

Examples of such a high-molecular polymer include, for example, the following, but are not limited thereto.

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,
Silicon-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole and the like can be mentioned.

The binder for the photoconductive layer of the type (1) can be appropriately selected from the binders for the charge generation layer and the charge transport layer.

These binders can be used alone or as a mixture of two or more.

When preparing the electrophotographic photoreceptor of the present invention, an additive such as a plasticizer or a sensitizer may be used together with the binder.

As a plasticizer, biphenyl, biphenyl chloride, o-terphenyl, p-terphenyl, dibutyl phthalate,
Dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphate, methyl naphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene, dilauryl thiodipropionate, 3,5-dinitrosalicylic acid, dimethyl phthalate, dibutyl phthalate, diisobutyl adipate, dimethyl seba Cate, dibutyl sebacate, butyl laurate, methylphthalyl ethyl glycolate, various fluorohydrocarbons and the like.

In addition, to improve the surface properties of the electrophotographic photoreceptor,
Silicon oil or the like may be added.

Examples of the sensitizer include chloranil, tetracyanoethylene, methyl violet, rhodamine B, cyanine dye, merocyanine dye, pyrylium dye, thiapyrylium dye, JP-A-58-65439, JP-A-58-102239, and JP-A-58-1.
Compounds described in Nos. 29439 and 62-71965 can be exemplified.

Alcohols (eg, methanol,
Ethanol, isopropanol, etc.), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), amides (eg, N, N-
Dimethylformamide, N, N-dimethylacetamide, etc.), esters (eg, methyl acetate, ethyl acetate,
Butyl acetate, etc.), ethers (eg, tetrahydrofuran, dioxane, monoglyme, diglyme, etc.), halogenated hydrocarbons (eg, methylene chloride, chloroform, methyl chloroform, carbon tetrachloride, monochlorobenzene, dichlorobenzene, etc.) alone Alternatively, they can be used as a mixture.

The application can be performed using a general-purpose coating method such as spraying, roller coating, spinner coating, blade coating, and dip coating.

In the present invention, an adhesive layer or a barrier layer can be provided between the conductive support and the photoconductive layer, if necessary. Materials used for these layers include, in addition to the high molecular polymer used for the binder, gelatin,
Casein, polyvinyl alcohol, ethyl cellulose,
Carboxy-methylcellulose, vinylidene chloride based polymer described in JP-A-59-84247, polymer latex,
The styrene-butadiene polymer latex described in 59-114544, aluminum oxide, or the like, and the thickness of these layers is preferably 0.1 to 5 μm.

In the present invention, an overcoat layer can be provided on the photoconductive layer if necessary. The overcoat layer may be a mechanically matted one or a resin layer containing a matting agent. In this case, as the matting agent, silicon dioxide, glass particles, alumina, starch, titanium oxide, zinc oxide, polymethyl methacrylate, polystyrene, polymer particles such as phenolic resin, and U.S. Pat.Nos. 2,701,245 and 2,992,101 Matting agents described in the book are included. These are 2
More than one species can be used in combination.

The resin used for the overcoat layer may be selected from various known resins in addition to the resin used for photoconductivity.

Although the present invention has been described in detail above, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having excellent sensitivity, a small change in the charging potential in repeated use, a small residual potential, and high printing durability and high durability. is there.

The present invention can be widely applied to the field of the electrophotographic photoreceptor of the present invention and a photoreceptor of a printer using a laser or a cathode ray tube as a light source as well as an electrophotographic copying machine. In particular, since it has high sensitivity even in a long wavelength region, it can be applied to a photoconductor of a printer using a laser such as a semiconductor laser and a He-Ne laser as a light source.

Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples. In the examples, “parts” means “parts by weight”.

Example 1 ε-type copper phthalocyanine (Riofoton EPPC: manufactured by Toyo Ink Co., Ltd.) 3.0 parts Exemplified compound (1) 0.3 part Polyester resin (Vylon 200: manufactured by Toyobo Co., Ltd.) 3.0 parts Hydrazone compound 3.0 parts 100 parts of tetrahydrofuran was put together with glass beads in a 500 ml glass container and dispersed with Paint Sieker (Toyo Seiki Seisakusho Co., Ltd.) for 60 minutes, and then the glass beads were filtered to obtain a dispersion liquid for the photoconductive layer.

Next, the dispersion liquid for a photoconductive layer is coated on a conductive support (75 μm polyethylene terephthalate film provided with a vapor-deposited aluminum film on the surface thereof; surface resistance: 10 ³ Ω) using a wire round rod and dried. Thus, an electrophotographic photosensitive member having a photoconductive layer of 20 μm was obtained.

Next, the electrical characteristics of the created electrophotographic photoreceptor were measured using EPA-810.
Using 0 (manufactured by Kawaguchi Electric Co., Ltd.), the measurement was performed under the condition that corona charging was performed at +8.0 kV by a static method and monochromatic light of 780 nm was exposed at a light intensity of 1 mw / m ² . Charging after surface potential (V _0), the ratio of the charge retention rate for V ₀ which the surface potential after 10 seconds from immediately after charging (DD _10), also as a sensitivity, the surface potential before exposure is 12 to optical attenuation Exposure amount (E ₅₀ ) and exposure amount that becomes 1/10 (E ₉₀ ) and exposure amount as residual potential (V _R ) 100μ
When the surface potential at J / cm ² was examined, it was V ₀ + 660V E ₅₀ 2.1 μJ / cm ² E ₉₀ 8.0 μJ / cm ² DD ₁₀ 72% V _R + 24V.

Comparative Example 1 From the coating solution for photoconductive layer of Example 1, Exemplified Compound (1)
An electrophotographic photoreceptor was prepared in exactly the same manner as in Example 1 except for the above. When the electrical characteristics of this electrophotographic photosensitive member were measured under the same conditions as in Example 1, it was V ₀ + 670V E ₅₀ 3.8 μJ / cm ² E ₉₀ 12.6 μJ / cm ² DD ₁₀ 75% V _R + 22V.

Example 2 3 parts of ε-type copper phthalocyanine (Liophoton EPPC), 0.3 parts of Exemplified compound (1) and 3 parts of polyester resin (Vylon 200) were dissolved in 100 parts of tetrahydrofuran with a ball mill and dispersed for 20 hours, and then the wire. Conductive support (aforesaid Al vapor deposition film) using a round rod
The resultant was coated and dried to obtain a charge generation layer having a thickness of 0.5 μm.

Next, a hydrazone compound is placed on the charge generation layer. A solution prepared by dissolving 9.3 parts and 10 parts of bisphenol A polycarbonate in 50 parts of dichloromethane was applied using a wire round rotor and dried to form a charge transport layer having a thickness of 20 μm to prepare an electrophotographic photoreceptor. . The electric characteristics of this electrophotographic photosensitive member were measured under the same conditions as in Example 1 except that corona charging was performed at -8 kv. As a result, V ₀ -730V E ₅₀ 1.1 μJ / cm ² E ₉₀ 2.8 μJ / cm ² DD ₁₀ 76% It was V _R -25V. After that, the two steps of charging and exposure were repeated 10,000 times, and the electrical characteristics were examined, but there was almost no change from the characteristics before the repetition.

Comparative Example 2 Example 2 was the same as Example 2 except that the exemplified compound (1) was omitted.
An electrophotographic photoreceptor was prepared in exactly the same manner as described above. When the electrical characteristics of this electrophotographic photosensitive member were measured under the same conditions as in Example 2, it was V ₀ -738V E ₅₀ 2.0 μJ / cm ² E ₉₀ 5.8 μJ / cm ² DD ₁₀ 79% V _R -24V.

Example 3 The ε-type copper phthalocyanine of Example 2 (Liofoton EP
PC) to X-type metal-free phthalocyanine (Dainippon Ink Co., Ltd.)
An electrophotographic photoreceptor was prepared in exactly the same manner as in Example 2 except that Fastogen Blue 8120 was used. The electrical characteristics of this electrophotographic photosensitive member were measured under the same conditions as in Example 2, and as a result, V ₀ -735V E ₅₀ 0.6 μJ / cm ² E ₉₀ 1.7 μJ / cm ² DD ₁₀ 77% V _R -13V. Thereafter, the two steps of charging and exposure were repeated 10,000 times, and the electrical characteristics were examined. As a result, there was almost no change from the characteristics before the repetition.

Comparative Example 3 Example 3 was the same as Example 3 except that the exemplified compound (1) was omitted.
An electrophotographic photoreceptor was prepared in exactly the same manner as described above. When the electrical characteristics of this electrophotographic photosensitive member were measured under the same conditions as in Example 2, it was V ₀ -740V E ₅₀ 0.9 μJ / cm ² E ₉₀ 2.7 μJ / cm ² DD ₁₀ 78% V _R −15V.

Example 4 ε-type copper phthalocyanine of Example 2 (Riofoton EP
PC) to α-type titanyl copper phthalocyanine (manufactured by Toyo Ink)
An electrophotographic photoreceptor was prepared in exactly the same manner as in Example 2 except that the above was replaced. The electrical characteristics of this electrophotographic photosensitive member were measured under the same conditions as in Example 2, and as a result, V ₀ -710V E ₅₀ 0.37 μJ / cm ² E ₉₀ 1.1 μJ / cm ² DD ₁₀ 75% V _R -12V. Thereafter, the two steps of charging and exposure were repeated 10,000 times, and the electrical characteristics were examined. As a result, there was almost no change from the characteristics before the repetition.

Comparative Example 4 Example 3 was the same as Example 4 except that the exemplified compound (1) was omitted.
The electrical characteristics of the electrophotographic photoreceptor were determined in exactly the same manner as in Example 2.
As a result of measurement under the same conditions as above, V ₀ −720V E ₅₀ 0.5 μJ / cm ² E ₉₀ 1.5 μJ / cm ² DD ₁₀ 77% V _R −11V.

Examples 5 to 10 Electrophotographic photoreceptors were prepared in exactly the same manner as in Example 2 except that the exemplified compounds of Table 1 were used instead of the exemplified compound (1) of Example 2. Table 1 shows the electronic characteristics of this electrophotographic photosensitive member. The measurement of the electrical characteristics was performed under the same conditions as in Example 2.

Example 11 X-type metal-free phthalocyanine (manufactured by Dainippon Ink and manufactured by Fastog
en Blue 8120) 3 parts polyester resin (Byron)
3 parts of chlorobenzene was dissolved in 100 parts of chlorobenzene and dispersed in a ball mill for 20 hours, then 0.3 parts of Exemplified Compound (1) was dissolved, coated on a conductive support using a wire round rod, and dried. As a result, a charge generation layer having a thickness of 0.5 μm was obtained. Thereafter, a charge transport layer was provided in the same manner as in Example 2 to prepare an electrophotographic photosensitive member. The electrical characteristics of this electrophotographic photosensitive member were measured under the same conditions as in Example 2, and as a result, V ₀ −730V E ₅₀ 0.6 μJ / cm ² E ₉₀ 1.7 μJ / cm ² DD ₁₀ 76% V _R −12V. . After that, two steps of charging and exposure were repeated 10,000 times, and the electrical characteristics were examined. As a result, there was almost no change from the characteristics before the repetition.

Comparison of Example 1 with Comparative Example 1, Examples 2, 5 to 10 with Comparative Example 2, Examples 3, 11 with Comparative Example 3, and Example 4 with Comparative Example 4 is represented by the general formula (I). The electrophotographic photoconductor with the addition of the compound shown in FIG.
It is twice as sensitive. However, it can be seen that there is no large difference in chargeability, dark decay, and residual potential, and good electrophotographic characteristics are maintained. Furthermore, in Examples 2, 3, 4, and 11, it was confirmed that the electric characteristics after 10,000 times of repeated use had almost no change from the initial characteristics.

As described above, the electrophotographic photoreceptor shown in the examples satisfies the object of the present invention "an electrophotographic photoreceptor having high sensitivity, high potential stability in repeated use, small residual potential, and high durability". It turns out to be something.

Continuation of the front page (56) Reference JP 61-20951 (JP, A) JP 58-65438 (JP, A) JP 58-65439 (JP, A)

Claims (4)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a photoconductive layer provided on a conductive support, wherein the photoconductive layer comprises a phthalocyanine pigment and at least one compound represented by the following general formula (I) or general formula (II). An electrophotographic photoreceptor for a copying machine or an optical printer, which is characterized by containing. General formula (I) General formula (II) In formulas (I) and (II), Z represents a sulfur atom or an oxygen atom, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each a hydrogen atom, an alkyl group or an aryl group. Represents,
R ¹ and R ² , or R ³ may be the same or different from each other.
And R ⁴ may be linked to each other, and in the general formula (I), R ¹ , R ² , R ³ and R ⁴ may be linked to form a bridged ring as a whole, and R ⁷ is 2 Represents a valent arylene group, aralkylene group, polymethylene group or branched alkanediyl group. 2. The copying machine according to claim 1, wherein the photoconductive layer is a single layer containing a phthalocyanine pigment and a compound represented by the general formula (I) or the general formula (II). Or an electrophotographic photoreceptor for an optical printer. 3. A photoconductive layer comprising a charge generation layer and a charge transport layer containing a phthalocyanine pigment and a compound represented by formula (I) or formula (II). An electrophotographic photoconductor for a copying machine or an optical printer as described above. 4. The electrophotographic photosensitive member for a copying machine or an optical printer according to claim 1, wherein the light source of the copying machine or the optical printer is a laser beam. body.